EP4683972A1 - Silicon phthalocyanine and tribenzophthalocyanine dyes and their use in diagnosis and therapy - Google Patents

Abstract

The present application relates to new A3B-type silicon phthalocyanine including new silicon tribenzophthalocyanine dyes.

Description

SILICON PHTHALOCYANINE AND TRIBENZOPHTHALOCYANINE DYES AND THEIR

USE IN DIAGNOSIS AND THERAPY

Background of the invention

The present invention relates (1 ) to new A₃B-type silicon phthalocyanine dyes including new silicon tribenzophthalocyanine (from here "3:1 naphthalo-/phthalocyanine hybrid") dyes and (2) to derivatives of these dyes wherein they bind covalently to molecules (e.g. antibodies) forming bioconjugates that specifically bind non-covalently to a biological structure (e.g. an antigen). The A₃B-type silicon phthalocyanines including the silicon 3:1 naphthalo- Zphthalocyanine hybrids, both as shown in formula I, according to the present invention can be advantageously used in diagnosis and therapy, in particular in targeted photodynamic therapy (from here: "TPDT") for which purpose a silicon phthalocyanine core or a 3:1 naphthalo- Zphthalocyanine hybrid core is connected via a linker "L" to a reactive or activable group "Q" which may form a covalent bond to certain molecules, which in turn bind to a well-defined biological structure. The silicon phthalocyanine dyes including 3:1 naphthalo-/phthalocyanine hybrid dyes according to the invention (from here for simplicity’s sake referred to as "silicon phthalocyanine dyes according to the present invention") absorb light (alone or when covalently bound to molecules, such as antibodies) from the red to the near-infrared (from here: "NIR") parts of the electromagnetic spectrum. This property may be used for diagnosis in order to indicate the location of the above-mentioned biological structure or for therapy since the energy of the red or NIR light is directed to the above-mentioned biological structures, which may be destroyed thereby. The silicon phthalocyanine dyes according to the present invention are dyes, not pigments. They are water-soluble (because they contain multiple charges introduced via their twice occurring substituents OR), which is important since these compounds are used in a biological (aqueous) environment.

The activation of many kinds of dyes by light for destroying e.g. tumor cells involves, as one believes, the formation of oxygen in its singlet excited-state (from here "singlet oxygen") via the following steps:

1 ) Absorption of light exclusively by a singlet ground-state dye molecule; as consequence thereof an electron is promoted from an occupied to an unoccupied molecular orbital; the dye molecule thus assumes a singlet excited-state. 2) Spin inversion of one electron in such an excited dye molecule; this provides a longer- lived triplet excited-state dye molecule in a process known as intersystem crossing.

3) Energy transfer between such a triplet dye molecule and molecular oxygen - omnipresent in the aqueous solutions which make up biological systems - which has a triplet ground-state; this regenerates a singlet ground-state dye molecule (ready to re-participate in step 1) and singlet oxygen.

4) Other than triplet oxygen such singlet oxygen attacks constituents of the surrounding biological systems and eventually destroys the latter (see step 5). In the absence of dye(s) with the mentioned properties, (visible) light cannot convert triplet oxygen (cell-compatible) into singlet oxygen (cell-damaging). That insight led to the notion of dyes "sensitizing" triplet oxygen towards the uptake of energy from light; accordingly, a dye for photodynamic therapy (from here "PDT"), TPDT, or photo/mmunotherapy (from here "PIT") is often referred to as a "photosensitizer" (from here: "PS").

5) Singlet oxygen can directly kill tumor cells by the induction of cell death within the light focus, including immunogenic cell death (ICD); it can cause destruction of tumor vasculature and it can produce an acute inflammatory response that induces a host immune response against released antigens from the dying tumor cells that amplifies the therapeutic effects. Such mechanisms result in the eradication of tumor cells even outside of the light focus, in particular circulating tumor cells or clusters of metastatic tumor cells.

An A₃B-type silicon phthalocyanine dye of the prior art which is deemed useful for binding covalently to molecules (e.g. antibodies) binding non-covalently to biological structures is disclosed in US Patent 7,005,518 as shown as structure Li-Cor-A below; it has an absorption maximum at λ = 680 nm (which corresponds to red light). The dye may be bound covalently to proteins, in particular to antibodies, by an aminolysis of an M-hydroxysuccinimide ester moiety. The silicon phthalocyanine dyes of the prior art claimed in this US Patent 7,005,518 have a silicon atom located in the center of the phthalocyanine core and thereby within an octahedral coordination sphere such that it binds to 4 nitrogen atoms equatorially and to 2 silyloxy (from here: "siloxy") groups axially. Furthermore, WO 2021/207691 discloses A₄-type phthalocyanine dye compounds of the prior art as shown as structure Rakuten-A below; they were developed, inter alia, for deriving "therapeutic conjugates as the photosensitizing agents in light-based therapies including photoimmunotherapy":

The A₃B-type silicon phthalocyanine-type dyes of the present invention differ from structures like Li-Cor-A (A₃B-type), Rakuten-A (A₄-type), and conceptually related A₄-type silicon phthalocyanines (K. Takahashi, A. Sugiyama, K. Ohkubo, T. Tasumi, T. Kodama, K. Yamatsugu, M. Kanai, Synlett 2021, 32, 1098-1023) or naphthalocyanines (M. A. Saad, R. Pawle, S. Selfridge, L. Contreras, M. Xavierselvan, C. D. Nguyen S. Mallidi, Tayyaba Hasan, M. J. Mol. Sci. 2023, 24, 2241 ), respectively, as disclosed in the prior art. The newly designed silicon phthalocyanine dyes according to the present invention have improved properties when used in diagnosis or therapy. The silicon phthalocyanine dyes according to the present invention can preferably be used in TPDT of tumors.

Summary of the invention

The present invention relates to A₃B-type silicon phthalocyanines having any of structures B and iso-B in Formula I including 3:1 naphthalo-/phthalocyanine hybrid dyes as represented by structures C and feo-C in the same

structure B or structure C or structure iso-B: or structure iso-C:

Formula I.

Therein:

-O-R is -O(-R¹)_p(-O)_q-R²(-R³)_s

R¹ is selected from C₁-C₃ alkyl and C(O), p is 0 or 1 , q is 0 or 1 , with the proviso that if p is 0, then q is 0,

R² is selected from alkyl, aryl, arylalkyl, (heteroaryl)alkyl, alkoxyalkyl, and heteroaryl,

R³ is -A¹ -A²,

A¹ is selected from (heterocyclyl)alkyl-(O)r, r is 0 or 1 A² is selected from di-, tri- and tetrasaccharides and -C₁-C₆ alkyl, which is substituted with at least one group selected from sulfonic acid, phosphonic acid, carboxylic acid, and salts thereof, and s is 1 , 2 or 3,

L is a linker unit -O~L¹-L² being bound via the oxygen either to C^β of structures B and C to form an ether motif C^β-O-L¹-L² or to C^αof structures iso-B and iso-C to form an ether motif C^α-O-L¹-L²,))

L¹ is selected from aryl, arylaryl, (arylalkyl)aryl, (arylalkoxy)aryl, [(arylalkyl)amino]aryl, aroylaryl, (arylsulfanyl)aryl, and arylsulfonylaryl

L² is selected from ureido(C₁-C₆ alkyl), ureido(C₂-C₆ alkenyl), ureido(C₂-C₆ alkynyl), carbamoyloxy(C₁-C₆ alkyl), carbamoyloxy(C₂-C₆ alkenyl), carbamoyloxy(C₂-C₆ alkynyl), (alkoxycarbonyl)amino(C₁-C₆ alkyl), (alkoxycarbonyl)amino(C₂-C₆ alkenyl), (alkoxycarbonyl)amino(C₂-C₆ alkynyl), [ureido(C₁-C₆ alkyl)]amino, [carbamoyloxy(C₁- C₆ aikyl)]amino, [(alkoxycarbonyl)amino(C₁-C₆ alkyl)]amino, ureido(C₁-C₆ alkoxy), carbamoyloxy(C₁-C₆ alkoxy), (alkoxycarbonyl)amino(C₁-C₆ alkoxy), [ureido(C₁-C₆ alkyl)]thio, [carbamoyloxy(C₁-C₆ alkyl)]thio, [(alkoxycarbonyl)amino(C₁-C₆ alkyl)]thio, {[ureido(C₁-C₆ alkyl)]amino}carbonyl, {[carbamoyloxy(C₁-C₆ alkyl)]amino}carbonyl, {[(alkoxycarbonyl)amino(C₁-C₆ alkyl)]amino}carbonyl, [ureido(C₁-C₆ alkoxy)]carbonyl, [carbamoyloxy(C₁-C₆ alkoxy)]carbonyl, [(alkoxycarbonyl)amino(C₁-C₆ alkoxy)]carbonyl, [ureido(C₁-C₆ alkyl)]carbonyl, [ureido(C₂-C₆ alkenyl)]carbonyl, [ureido(C₂-C₆ alkynyl)]carbonyl, [carbamoyloxy(C₁-C₆ alkyl)]carbonyl, [carbamoyloxy(C₂-C₆ alkenyl)]carbonyl, [carbamoyloxy(C₂-C₆ alkynyl)]carbonyl, [(alkoxycarbonyl)amino(C₁- C₆ alkyl)]carbonyl, [(alkoxycarbonyl)amino(C₂-C₆ alkenyl)]carbonyl, and [(alkoxycarbonyl)amino(C₂-C₆ alkynyl)]carbonyl, is -Q¹(-Q²)_t— Q^{3 1} is a linear or branched, preferably linear, C₁-C₆ alkyl group, 2 is selected from aryl and alkylaryl, is 0 or 1 , and 3 is selected from the group consisting of a) a carboxylic acid, a corresponding acyl halide, a corresponding mixed anhydride, preferably aza-analogs resulting from additions to carbodiimides or condensations with uranium salts, a corresponding activated ester, b) an electrophilic C,C double bonds, preferably α,β-unsaturated esters, α,β- unsaturated lactones (including α-alkylidene lactones), α,β-unsaturated amides, α,β-unsaturated imides (including halogenated ones), α,β-unsaturated nitriles, α,β- unsaturated ketones, α,β-unsaturated sulfones, α,β-unsaturated sulfoxides, alk-1- enylphosphonates, nitroolefins, c) an alkyl halide, preferably a-haloketones and (haloacet)amides, an alkyl sulfonate, d) an isocyanate, isothiocyanate, e) a disulfide, a thiosulfonic acid ester, a trisulfide-S,S-dioxide, f) a phosphoramidite and g) an N -aryl-1 , 2, 4-triazolin-3, 5-dione.

The silicon phthalocyanine dyes according to the present invention differ structurally from the A₃B-type silicon phthalocyanine dyes Li-Cor-A claimed in the US Patent 7,005,518 and particularly from the only dye of that kind whose synthesis is specifically described in this patent in various aspects. Most fundamentally by the silicon atom in the center of the molecules not binding axially to 2 siloxy groups but to 2 alkoxy groups, preferably to 2 arylalkoxy groups, or to 2 aryloxy groups or to 2 acyloxy groups or to 2 alkylcarbonato groups or 2 arylcarbonato groups. Bathochromic shifts of over 100 nm were achieved by another fundamental difference of the dye structures of the present invention compared to the structures Li-Cor-A claimed in US Patent 7,005,518, namely by extending the unsaturated core of the B-type silicon phthalocyanines to the unsaturated core of the C-type and /so-C-type silicon 3:1 naphthalo- /phthalocyanine hybrids. Any bathochromic shift of dyes for (T)PDT and PIT is beneficial because the light required for using dyes as PSs is known to penetrate the deeper into tissue the longer the absorption wavelength of the dye employed; as a consequence, e.g. more targets cells, can be affected by singlet oxygen in tissues than if this infrared shift was absent.

In another embodiment, the invention relates to the silicon phthalocyanines according to the present invention for use in therapy of tumor associated diseases.

In an embodiment, the invention relates to the silicon phthalocyanines according to the present invention for use in theranostics whereby the dye is activated by a light source in the red / near infrared wavelength for diagnosis and therapy.

In an embodiment, the invention relates to the silicon phthalocyanines according to the present invention for use in ex vivo diagnosis. In an embodiment, the invention relates to the use of a compound of formula HO-L¹-Hal in the preparation of the silicon phthalocyanines according to the present invention, wherein L¹ is defined as in claim 1 and Hal is a halogen selected from I, Br, and CL

In an embodiment, the silicon phthalocyanine of the present invention are for use in medicine for the selective removal of benign cells. Preferably, these benign cells are hyperplastic tissues or cells targeted for removal in aesthetic medicine.

In a further embodiment, the invention provides a pharmaceutical formulation comprising a silicon phthalocyanine according to the present invention. Preferably, the pharmaceutical formulation is a gel, a cream, a solution, or injectable, which facilitates the precise application and distribution of the dye in the targeted tissues.

Detailed description

The following definitions are relevant in connection with the embodiments of the present invention.

The prefix "C_y-C_x" as used herein refers to the number of carbon atoms of the respective group. For heteroaryl groups, the prefix "C_y-C_x" refers to the number of atoms (including heteroatoms) in the aromatic system.

As used herein, singular forms, such as "a", ''an'', and ''the”, include both singular and plural referents unless the context clearly dictates otherwise. By way of example, ''silicon phthalocyanine" means one silicon phthalocyanine or more than one silicon phthalocyanine.

The term "silicon phthalocyanine dyes according to the present invention" or "silicon phthalocyanines according to the present invention" refers to silicon phthalocyanine dyes as represented by structures B and iso-B in Formula I including 3:1 naphthalo-/phthalocyanine hybrid dyes as represented by structures C and iso-C in Formula I.

The term "aryl" as used herein by itself or as part of another group refers to a monocyclic, bicyclic or tricyclic aromatic ring system having from six to fourteen carbon atoms (i.e. , C₆-C₁₄ aryl). Non-limiting exemplary aryl groups include phenyl (abbreviated as "Ph"), naphthyl, phenanthryl, anthracenyl, indenyl, biphenylyl including fluorenyl. The term "aryl" as used herein encompasses phenyls, naphthyls, phenanthryls, anthracenyls, and biphenylyls including fluorenyls that are substituted by one or more substituents, e.g. halo, nitro, cyano, hydroxy, alkoxy, and alkyl.

The term "alkyl" as used herein by itself or as part of another group refers to a straight- or branched-chain aliphatic hydrocarbon containing one to twelve carbon atoms (i.e., C₁-C₁₂ alkyl).

In one embodiment, the alkyl group is chosen from a straight chain C₁-C₁₀ alkyl group. In another embodiment, the alkyl group is chosen from a branched chain C₃-C₁₀ alkyl group. In another embodiment, the alkyl group is chosen from a straight chain C₁-C₆ alkyl group. In another embodiment, the alkyl group is chosen from a branched chain C₃-C₆ alkyl group. In another embodiment, the alkyl group is chosen from a straight chain C₁-C₄ alkyl group. In another embodiment, the alkyl group is chosen from a branched chain C₃-C₄ alkyl group. In another embodiment, the alkyl group is chosen from a straight or branched chain C₃-C₄ alkyl group. Non-limiting exemplary C₁-C₁₀ alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, iso-butyl, 3-pentyl, hexyl, heptyl, octyl, nonyl, decyl, and the like. Non-limiting exemplary C₁-C₄ alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, sec- butyl, tert-butyl, and iso-butyl.

The skilled person will understand that the term "alkyl" as used herein also encompasses "alkylene", including as non-limiting examples e.g. methylene (-CH₂-), ethylene (-CH₂CH₂-), or propylene (-CH₂CH₂CH₂-), when the alkyl group is not a terminal group, but is part of a chain, such as e.g. R¹ and R² in -O(-R¹)_p(-O)_q-R²(-R³)_s. The same considerations also apply to other groups or substituents as defined in the present application when being part of a chain, and not a terminal group. For example, the term (hetero)aryl also encompasses “(hetero)arylene”.

Furthermore, the term "alkyl" also includes branched alkyls such as "alkan-1 ,ω -diyl", "alkan- 1 ,ω ,ω -triyl" and "alkan-1 ,ω ,ω ,ω -tetrayl", e.g. when -R²(-R³)_s, R² is "alkyl" and s is 1 , 2 or 3.

The term "heteroaryl" as used herein by itself or as part of another group refers to a monocyclic or bicyclic heteroaromatic ring system having from five to ten atoms (including 1 , 2, 3, or 4 heteroatoms independently chosen from oxygen, nitrogen and sulfur, i.e. C₅-C₁₀ heteroaryl). In one embodiment, the heteroaryl is a C₅ heteroaryl. In another embodiment, the heteroaryl is a C₆ heteroaryl. Non-limiting exemplary heteroaryl groups include but are not limited to furyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl, oxazolyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, 1 ,2,3-triazinyl, 1 ,2,4,5-tetrazinyl, benzofuryl, indolyl, benzothienyl, quinolinyl, isoquinolinyl, cinnolinyl, quinaziolinyl, quinoxalinyl, and phthalazinyl. The term "heteroaryl" as used herein encompasses heteroaryls that are substituted by one or more substituents, e.g. halo, nitro, cyano, hydroxy, and alkyl

The term "alkenyl" as used herein by itself or as part of another group refers to an alkyl group as defined above containing one, two or three carbon-to-carbon double bonds. In one embodiment, the alkenyl group is chosen from a C₂-C₆ alkenyl group having 2, 3, 4, 5 or 6 carbon atoms. In another embodiment, the alkenyl group is chosen from a C₂-C₄ alkenyl group having 2, 3, or 4 carbon atoms. Non-limiting exemplary alkenyl groups include ethenyl, propenyl, isopropenyl, butenyl, sec-butenyl, pentenyl, and hexenyl.

The term "alkynyl" as used herein by itself or as part of another group refers to an alkyl group as defined above containing one to three carbon-to-carbon triple bonds. In one embodiment, the alkynyl has one carbon-to-carbon triple bond. In one embodiment, the alkynyl group is chosen from a C₂-C₆ alkynyl group having 2, 3, 4, 5 or 6 carbon atoms. In another embodiment, the alkynyl group is chosen from a C₂-C₄ alkynyl group having 2, 3 or 4 carbon atoms. Non- limiting exemplary alkynyl groups include ethynyl, propynyl, butynyl, 2-butynyl, pentynyl, and hexynyl groups.

The term "alkoxy" as used herein by itself or as part of another group refers to an optionally substituted alkyl, optionally substituted alkenyl or optionally substituted alkynyl attached to a terminal oxygen atom. In one embodiment, the alkoxy group is chosen from a C₁-C₆ alkoxy group. In another embodiment, the alkoxy group is chosen from a C₁-C₄ alkyl attached to a terminal oxygen atom, e.g., methoxy, ethoxy, tert-butoxy, pentoxy and hexoxy. It is preferred that the term "alkoxy" refers to a linear C₁-C₆ alkyl group attached to a terminal oxygen atom.

The term "arylalkoxy" as used by itself or as part of another group refers to an aralkyl group attached to a terminal oxygen atom. A non-limiting exemplary arylalkoxy group is PhCH₂O-.

The term "heterocyclyl" as used by itself or as part of another group refers to saturated and partially unsaturated (e.g., containing one or two double bonds) cyclic groups containing one, two, or three rings having from three to fourteen ring members (i.e. , a 3-, 4-, 5-, 6-, 7-, 8-, 9-, 10-, 11-, 12-, 13- or 14-membered heterocyclyl) and at least one heteroatom. Each heteroatom is independently selected from the group consisting of oxygen, sulfur, including sulfoxide and sulfone, and/or nitrogen atoms. The term "heterocyclyl" encompasses heteroaryl groups. The heterocycle may be unsubstituted or optionally substituted with one to four substituents independently selected from halo, nitro, cyano, hydroxy, amino, alkoxy, alkyl, alkenyl, alkynyl, aryl, heteroaryl, heterocyclyl, alkoxyalkyl, and (heteroaryl)alkyl. Substitution may occur on any available carbon or nitrogen atom, and may form a spirocycle. Non-limiting exemplary heterocyclyl groups include [1 ,2,3]triazolyl (D), tetrahydrocycloocta[1,2,3]triazolyl (E), 3,4,5- triazatricyclo[5.2.1.0]decyl (F), 3,4,5-triazatricyclo[5.2.1.0]dec-3-enyl (G), and 1 ,6- dihydropyridazinyl (H).

The term "alkylcarbonato" as used herein by itself or as part of another group refers to a carbonate group (-O-C(-O)-O-) that is linked to an alkyl group. Non-limiting examples of alkylcarbonato include methylcarbonato (-O-C(=O)-O-CH₃). Likewise, the term "arylcarbonato" as used herein by itself or as part of another group refers to a carbonate group (-O— C(=O)- O-) that is linked to an aryl group. Non-limiting examples of arylcarbonato include phenylcarbonato (-O-C(=O)-O-C₆H₅).

The term "arylal kyl" as used herein by itself or as part of another group refers to an alkyl group substituted with one, two, or three, preferably one, aryl groups. In one embodiment, the arylalkyl group is a C₁ -C₄ alkyl substituted with one optionally substituted aryl group. Non- limiting exemplary aralkyl groups include benzyl and phenethyl.

The term "ureido" as used herein by itself or as part of another group refers to a radical of the formula -NH-C(=O)-NH₂.

The term "carbamoyloxy" as used herein by itself or as part of another group refers to a radical of the formula -O-C(=O)-NH₂.

The term "alkoxycarbonyl)amino" as used herein by itself or as part of another group refers to a radical of the formula -NH-C(=O)-O-alkyl.

The term "ureido(C₁-C₆ alkyl)" as used herein refers to a group of formula -C₁-C₆ alkyl-NH- C(=O)-NH₂. The term "ureido(C₂-C₆ alkenyl)" as used herein refers to a group of formula -C₂- C₆ alkenyl-NH-C(=0)-NH₂.The term "ureido(C₂-C₆ alkynyl)" as used herein refers to a group of formula -C₂-C₆ alkynyl-NH-C(=O)-NH₂.

The term "carbamoyloxy(C₁-C₆ alkyl)'' as used herein refers to a group of formula -C₁-C₆ alkyl— 0-C(=0)-NH₂. The term "carbamoyloxy(C₂-C₆ alkenyl)'' as used herein refers to a group of formula -C₂-C₆ alkenyl-O-C(=O)-NH₂.The term "carbamoyloxy(C₂-C₆ alkynyl)" as used herein refers to a group of formula -C₂-C₆ alkynyl-O-C(=O)-NH₂.

The term "(alkoxycarbonyl)amino(C₁-C₆ alkyl)" as used herein by itself or as part of another group refers to a group of formula -(C₁-C₆ alkyl)-NH-C(=O)-O-alkyl. The term "(alkoxycarbonyl)amino(C₂-C₆ alkenyl)" as used herein by itself or as part of another group refers to a group of formula -(C₂-C₆ alkenyl)-NH-C(=O)-O-alkyl. The term "(alkoxycarbonyl)amino(C₂-C₆ alkynyl)" as used herein by itself or as part of another group refers to a group of formula -(C₂-C₆ alkynyl)-NH-C(=O)-O-alkyl.

The term "salt" used herein refers to but is not limited to, alkaline metal salts such as a sodium salt, potassium salt, cesium salt; alkaline earth metals such as a magnesium salt, calcium salt, and ammonium salts.

Composite terms as used herein, such as "heteroarylalkoxy", are to be understood in their broadest technically sensible way and may refer to a connectivity of -heteroarylalkoxy or heteroarylalkoxy-. However, it is preferred that composite terms are interpreted in that the last- mentioned group is connected "first", e.g. -O-alkyl-heteroaryl. In case the composite term has more than one bond/connection, it is preferred that the last-mentioned group is connected first and the first mentioned group connects the group to the next substituent. For example, for -O- L¹-L²-Q and L² being ureido(C₂-C₆ alkynyl), it is preferred that the connectivity is -O-L¹-(C₂- C₆ alkynyl)-NH-C(=O)-NH-Q.

The term "aroyl" as used herein by itself or as part of another group refers to a carbonyl group substituted with one aryl group. Non limiting exemplary aroyl groups include -C(=O)-C₆H₅.

The term "arylsulfonyl" as used herein by itself or as part of another group refers to a sulfonyl (SO2) group substituted with one aryl group. Non limiting exemplary arylsulfonyl groups include -SO2-C₆H₅. Non-limiting examples for "di-, tri- or tetrasaccharides" as used herein are maltose, cellobiose, isomaltose, gentiobiose, mannobiose, xylobiose, lactose, maltotriose, panose, 2’- fucosyllactose, 3-fucosyllactose, and maltotetraose.

Preferred embodiments according to the invention are defined hereinafter. The preferred embodiments are preferred alone or in combination. Further, it is to be understood that the following preferred embodiments refer to all aspects of the present invention, i.e. the silicon phthalocyanine, silicon phthalocyanine for use, and the use of a compound of formula HO-L¹- Hal.

The naphthalo-/phthalocyanine hybrid dyes as represented by structures C and iso-C in Formula I are preferred. It has been found that these dyes as represented by structures C and /so-C in Formula I can be prepared, in particular, purified more easily than the silicon phthalocyanine dyes of the prior art and even the silicon phthalocyanine dyes as represented by structures B and iso-B in Formula I.

In a preferred embodiment, p is 1 and R¹ is C₁-C₃ alkyl. In a preferred embodiment, q is 0.

In a preferred embodiment, R² is selected from a linear or branched, more preferably linear, C₁-C₆ alkyl group, phenyl, naphthyl, phenanthryl, anthracyl, biphenylyl, pyridyl, pyrimidinyl, and pyridazinyl. In a more preferred embodiment, R² is selected from C₁-C₆ alkyl, phenyl, and pyridyl.

In case s is 2 or 3, each R³ may be selected independently. It is, however, preferred that each R³ is identical.

In a preferred embodiment, A¹ is ([1 ,2,3]triazolyl)alkoxy, tetrahydrocycloocta[1 ,2,3]triazolyl)alkoxy, (3,4,5-triazatricyclo[5.2.1.0]decyl)alkoxy, (3,4,5- triazatricyclo[5.2.1 ,0]dec-3-enyl)alkoxy or 1 ,6-dihydropyridazinyl)alkoxy.

In a preferred embodiment, A² is a C₁-C₆ alkyl substituted with a group from sulfonic acid, phosphonic acid, and salts thereof.

The linker unit L (-O-L¹-L²) is described below.

In a preferred embodiment, L² has the following structure.

, wherein n is 1 or 0,

X is selected from aryl, NH and O,

Y is selected from alkyl, aryl, NH, N_{without H} and O, and

Het and Het’ are independently selected from NH, O and S.

It is particularly preferred that Het is NH and Het’ is NH, Het is O and Het’ is NH, or Het is NH and Het’ is O.

In a preferred embodiment, L¹ is aryl, more preferably phenyl or naphthyl. In a preferred embodiment, L² is ureido(C₂-C₆ alkynyl), carbamoyloxy(C₂-C₆ alkynyl) or (alkoxycarbonyl)amino(C₂-C₆ alkynyl).

In an a particularly preferred embodiment, the linker L has a structure selected from the group consisting of any one of

Q is a reactive or an activable group which can form a covalent bond to a molecule specifically, whereupon the resulting entity, a bioconjugate, binds non-covalently to a biological structure. In particularly preferred embodiments the linker L is one of the (alk-l-ynylaryl)oxy structures

DD or EE of

The structure of Q -is -Q¹(-Q²)_t-Q³ is depicted below.

In a preferred embodiment is selected from the following structure: a preferred embodiment is selected from the following structure a preferred embodiment, is selected from any one of the following structures

In a preferred embodiment, accordingly, Q is selected from any one of the following structures:

or from the following structures according to Formula IIIe:

In a more preferred embodiment, Q is selected from any one of the structures W, WW, XX and YY of or from any one of the structures ZZ, AAA, BBB and CCC of

In a particularly preferred embodiment, Q is selected from any of the structures DDD, EEE and FFF of or from any one of the structures GGG, HHH and III of In the silicon phthalocyanine of the present invention, the residue Q according to Formula III is designed such as to form a covalent bond specifically or designed to be activable to form a covalent bond specifically to molecules binding non-covalently to biological structures. The mentioned molecules are preferably selected from but not limited to the group of antibodies, antibody fragments, nanoparticles, nanobodies, antigens, ligands, proteins, peptides, small molecules, inhibitors, aptamers, cells, phages, viruses, RNA, DNA, lipids, carbohydrates, polysaccharides, nanomaterials or chemical drugs.

An example of a preferred molecule-dye conjugate comprises therefore the following elements: a silicon phthalocyanine dye of the present invention which is conjugated (i.e. covalently bound) to a molecule (e.g. antibody) which can bind to a biological structure (e.g. antigen). Another example of such specific biological interaction is the binding of a ligand to its receptor.

The p-substituent in the B-part of the A₃B-type silicon phthalocyanines B or C or the a- substituent in the B-part of the A₃B-type silicon phthalocyanines iso-B or iso-C, all according to the present invention, contains β- or a-bound oxygen, a linker L, and a reactive or activable grouping Q as a -O-L-Q moiety. The -O-L- part of said -O-L-Q moiety may be synthesized advantageously from bifunctional reactants containing both a hydroxyarene moiety and a haloarene moiety - including halohydroxyarenes, but not limited to them. The aryloxy moiety of these reactants allows to synthesize A₃B-type silicon phthalocyanines, which display an 0- Ar group at C-β or at C-α, in a straightforward manner. The haloarene moiety of the same reactant acts as a re-functionalization site because it allows to vary the then-present A₃B-type silicon phthalocyanine into structurally different A₃B-type silicon phthalocyanines in a straightforward manner, namely by Cu-catalyzed, Pd-catalyzed or Cu-/Pd-cocatalyzed C,C or C, heteroatom coupling reactions. These re-functionalizations play a key-role in the synthesis of the silicon phthalocyanines of the invention. This is, firstly, because of their versatility, and secondly, because of making our phthalocyanine syntheses convergent and thereby shorter and higher-yielding than syntheses performed according to the prior art.

Such incorporations of combined hydroxyarene/haloarene precursors by forming an aryl- oxygen bond in conjunction with subsequent cross-couplings of the resulting haloarene moieties add up to an unprecedented strategy in the synthesis of A₃B-type phthalocyanines of whatever kind. The HO-C_aryl bond and the Hal-C_aryl bond can reside in one and the same mono- or multinuclear benzenoid aromatic of any kind or in two different mono- or multinuclear benzenoid aromatics of any kind which need not be annulated to each other yet can have a different connectivity with one another, Hal being I, Br or Cl. Thus, the use of a compound of formula HO-L¹-Hal in the preparation of the silicon phthalocyanines according to the present invention results in a unique and unprecedented synthetic strategy.

In preferred embodiments of the hydroxyarene/haloarene precursors (HO-L¹-Hal) of the 4- substituted or 3-substituted phthalodinitrile from which the B-part of the A₃B-type silicon phthalocyanines according to the present invention and thus their substituent -L-Q originate synthetically, the haloarene moiety of the respective A₃B-type silicon phthalocyanine intermediate is coupled by Pd-catalyzed or Cu-/Pd-cocatalyzed C,C coupling reactions. In a preferred embodiment, said coupling reaction is a Sonogashira coupling reaction.

In a preferred embodiment, the compound of formula HO-L¹-Hal is selected from any one of the structures JJJ, KKK, LLL, MMM, NNN, OOO, PPP and QQQ of

In the silicon phthalocyanines according to the present invention, the silicon atom located in the center of the molecule binds 2 identical groups OR axially; these groups may contain charged groups in the form of ion pairs (i.e. a salt) or di-, tri-, or tetrasaccharides. These groups increase the solubility of the silicon phthalocyanines according to the present invention in water.

In a preferred embodiment, the substituent R has any of the following structures of

In a more preferred embodiment, the substituent R of the silicon phthalocyanines according to the present invention has any of the structures UUU and VVV or of the following structures WWW and WWWW or of the following structure XXXX or of the following structures YYYY and ZZZZ

Preferred examples for structure XXXX include the following structures XXXXA and XXXXB:

In particularly preferred embodiments, the substituent R has the following structure WWW

Introducing the water-solubility conferring ion-pair moieties of all preferred silicon phthalocyanines according to the present invention may include "click reactions" between alkyne-containing silicon phthalocyanines and azide-containing sulfonates or azide-containing anions of other strong organic acids.

Each synthesis according to Figures 3-6 and 8-12 of the silicon phthalocyanines according to the present invention requires relatively few steps altogether. Moreover, each synthesis is very convergent. This convergency is a significant advantage compared to the synthesis of the silicon phthalocyanine dye Li-Cor-A of the prior art known from the US Patent 7,005,518.

Screening the most recent review articles in this regard makes more than clear that the vast majority of silicon phthalocyanine studies concerns silicon phthalocyanines of the A₄-type which cannot form bioconjugates. The A₄-type silicon phthalocyanines Rakuten-A from patent application WO 2021/207691 , which can form bioconjugates, are extremely exceptional in that regard. A₃B-type silicon phthalocyanines of the prior art can form bioconjugates also only in the very few cases where they were appropriately designed. Till date, syntheses of A₃B-type silicon phthalocyanines need not be longer than syntheses of A₄-type silicon phthalocyanines but current synthetic methodologies imply that the maximum theoretical yields of A₃B-type silicon phthalocyanine syntheses are lower than the maximum theoretical yields of A₄-type silicon phthalocyanine syntheses. It is therefore a particular advantage of the present invention that it furnishes A₃B-type silicon phthalocyanines according to the present invention very convergently and hence in considerably fewer steps in the longest linear sequence compared to the synthesis of the A₃B-type silicon phthalocyanine Li-Cor-A known from US Patent 7,005,518 or compared even to non-bioconjugating A₃B-type silicon phthalocyanines known from prior art. Very little has been established yet in terms of structure/activity relationships in essence because silicon phthalocyanine dyes with an ability to bioconjugate are very rare and hence almost exotic compounds. The most fundamental structure change in the A₃B-type silicon phthalocyanine Li-Cor-A from US Patent 7,005,518, which can bioconjugate, compared to the silicon phthalocyanines according to the present invention, which can also bioconjugate, concerns different choices for each dye’s pair of axial OR groups: In Li-Cor-A, both OR are silyloxy, whereas in the silicon phthalocyanines according to the present invention, both OR are alkoxy or aryloxy or acyloxy or alkylcarbonato or alkylcarbonato. The same kind of structure changes differentiates the A₄-type silicon phthalocyanine 36 of the prior art (formula: Figure 16), which cannot bioconjugate, from the A₄-type silicon phthalocyanine 37 of the prior art (formula: ibid.), which also cannot bioconjugate. A recent PIT study of these compounds led to the conclusion that compound 36 should cause more cell damage than compound 37 (H. Takakura, S. Matsuhiro, M. Kobayashi, Y. Goto, M. Harada, T. Taketsugu, M. Ogawa, "Axial- ligand-cleavable silicon phthalocyanines triggered by near-infrared light toward design of photosensitizers for photoimmunotherapy", J. Photochem. Photobiol. 2022, 426, 113749).

The absorption maxima in the UV/VIS spectra of the representative silicon phthalocyanine EMBODIMENT 1 (= "WB692-LB1"; formula: Figure 1), EMBODIMENT 2 (= "WB692-LB2"; formula: Figure 1 ), EMBODIMENT 3 (= "WB692-CB1"; formula: Figure 1 ), and EMBODIMENT 4 (= "WB692-CB2"; formula: Figure 1), all representatives of the silicon phthalocyanines B according to Formula I according to the present invention, occur at λ_max = 692 nm; this amounts to a bathochromic shift of 12 nm compared to the absorption maximum of the silicon phthalocyanine Li-Cor-A disclosed in US Patent 7,005,518 which occurs at λ_max = 680 nm. The absorption maxima in the UV/VIS spectra of the representative silicon phthalocyanine EMBODIMENT 5 (= "WB795-LB1"; formula: Figure 2) and EMBODIMENT 6 (= "WB795-CB1"; formula: Figure 2), both representatives of the silicon phthalocyanines C according to Formula I according to the present invention, occur at λ_max = 795 nm; this amounts to a bathochromic shift of 115 nm compared to the absorption maximum of the silicon phthalocyanine Li-Cor-A of the prior art disclosed in US Patent 7,005,518.

The structures of 6 representative particularly preferred embodiments of the silicon phthalocyanines according to the present invention are shown in Figures 1-2, and the synthetic sequences leading to them are detailed in Figures 3-6 and 8-12. One of the most preferred application areas of the silicon phthalocyanine dyes according to the present invention is TPDT. In the following some important terms are explained in more detail.

PDT (Photodynamic Therapy)

PDT is a clinical treatment modality for various diseases, including cancer. It involves the topical or systemic administration of a dye followed by selective irradiation of the target lesion with a specific wavelength of non-ionizing light, which activates the dye to trigger death of the target cells. Due to this two-step therapeutic process, PDT is a safe and minimally-invasive therapy. Nevertheless, classical non-targeted dyes lack sufficient tumor selectivity and are taken up into neighboring normal tissues, resulting in adverse side effects.

PDT employs nontoxic dyes and harmless visible light in combination with oxygen to produce cytotoxic reactive oxygen species that destroy malignant cells and tissues by multifactorial mechanisms including a direct cell-killing, destruction of vasculature to deprive the malignant tissues of oxygen and nutrient and the induction of acute inflammation that attracts leukocytes.

TPDT (Targeted Photodynamic Therapy)

PDT is therefore being investigated as a target specific treatment, also called TPDT. For this, the dyes are conjugated to carrier molecules, which specifically bind to antigens of the target cells. Dyes are preferred with high absorption in the red or NIR light spectrum, which offers deepest tissue penetration.

PIT (Photoimmunotherapy)

When molecules concerning the immune system, e.g. antibodies or antibody fragments, are used as binding moieties, TPDT is also called photoimmunotherapy (PIT).

Site-specific conjugation of dyes

To generate homogeneous products with predictable and often also improved characteristics, site-specific conjugation of diagnostic or therapeutic drugs to carrier molecules, is the preferred method. One method is to mutate amino acids in the carrier molecule to cysteines or to add cysteines for the conjugation of a dye via maleimide linkers. In an IgG antibody molecule, cysteines form disulfide bridges for the inter- and intra-chain connections of the heavy and light chains. When the dyes include maleimide linkers for the conjugation to cysteine residues, selective reduction of disulfide bonds in the hinge region or between the heavy and light chains of the IgG antibodies is necessary to generate free SH groups for conjugation. With such procedures, however, heterogeneous conjugates consisting of heavy chain-light chain molecules with only monovalent binding, or single heavy or light chains that can no longer bind to the target antigen, are produced.

Therefore, a preferred method for TPDT is to conjugate dyes to engineered cysteines in the binding moieties that do not influence their folding or binding for avoidance of heterogeneous conjugates with undefined binding properties.

• Modifications for stable linkage

Antibodies with engineered cysteines can be used for the site-specific conjugation of cytotoxic drugs having e.g. maleimide linkers and are also called thiomabs. In principle, all amino acids of an antibody molecule can be mutated to cysteines. The site-specific location of the conjugation site, however, can impact the stability of the linkage between a drug and an IgG antibody. In the following some preferred modifications are shown, whereby, however, variants thereof are within the knowledge of the person skilled in the art.

The preferred amino acids for stable linkage of an antibody with drugs via maleimide linkers in the CH₂ and CH3 domains comprise (EU numbering; abbreviations of the amino acids, see Table 1 ):

V262, I336, S337, R344, E388, N421, S424, E345, Q438, L443,

The preferred amino acids in the CL domain are:

A118, Q124, K126, T129, R142, K149, Q155, S171 , E195, L201 , V205, T206

• Modifications to modulate antibody effector functions

The structure of an IgG antibody is comprised of two antigen-binding Fab arms linked to a Fc domain via the hinge region. This structural arrangement allows antibodies to link bound antigens with humoral and cellular components of the immune system. Engagement of the humoral immune response is governed, in large part, by interactions of the antibody with the protein C1q and the initiation of a series of proteolytic events known as the complement cascade. Cytotoxicity initiated via the complement cascade is also termed complement dependent cytotoxicity (CDC).

The cellular immune response occurs mostly due to the interactions between the antibody and Fc gamma receptors (FcyRs). Intracellular signaling through the activating receptors is modulated through the phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs), which leads to effector functions such as antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and inflammation via the induction of cytokine secretion.

Moreover, half-life of IgG antibodies is attributed, in large part, to their ability to bind the neonatal Fc receptor (FcRn) through the Fc domain.

Preferred single amino acids for direct C1q interactions are (EU numbering):

D270, K322, P329, P331

Preferred key sequence motifs for FcyR interactions are

P232-S239, D265-D270, Y296-T299, N325-I332

Preferred key sequence motifs for FcRn interactions are

L251-S254, L309-Q311 , N434-Y436

Various studies have shown that mutations of specific amino acids in an antibody, which are inside or outside the key sequence motifs for C1q, FcyR or FcRn, can influence effector functions. These amino acids should be used preferentially for the cysteine mutations to simultaneously enhance the efficacy and/or safety of a TPDT.

In the case that increased effector function is desired (e.g. target cells outside the light focus are to be damaged during TPCT, like metastases that also express the target antigen), the preferred amino acids in the antibody molecule to be mutated to cysteines are for enhanced CDC (12):

S267, H268, S324, K326, E333, E345, E430, S440 for enhanced ADCC: L234, L235, G236, S239, F243, H268, D270, R292, S298, Y300, V305, K326, A330, 1332, E333, K334, P396

- for enhanced ADCP:

G236, S239, 1332

In the case that reduced effector functions are desired (e.g. for the reduction of off-target toxicities or to reduce the induction of pro-inflammatory cytokines), the preferred amino acids to be mutated to cysteines are:

- L234, L235, G236, P238, N₂97, L328, A330, P331(for lgG1 )

- V234, G237, P238, H268, V309, A330, P331 (for lgG2)

- S228, F234, L235, L236, G237, E318 (for lgG4)

In the case that a prolonged serum half-life is desired (e.g. for lowering the therapeutic dose and/or frequency of administration), the preferred amino acids for cysteine mutations are:

- T250, M252, S254, T256, V259, T307, V308, E380, M428, N434

Table 1 shows the meaning of the mutated amino acids in the one letter code.

Table 1

Induction of immunogenic cell death

It was found that PDT and TPDT/PIT resulted not only in functional damage of cell membranes of the targeted cells, but also to a rapid induction of an immunogenic cell death (ICD). Following IR700-based PIT, ICD was marked by activation of stress markers including heat shock proteins 70 and 90, dying signals such as calreticulin, ATP and HMGB1 , which promote maturation of immature dendritic cells, and initiation of a host immune response against released antigens from dying cancer cells that amplifies the therapeutic effect. Therefore, combination therapies that further enhance tumor-cell-selective systemic host-immunity are under investigation, e.g. use of T-cell activating type 1 cytokines, such as IL-2 and IL-15, immune-checkpoint inhibitors, such as anti-CTLA4 or anti-PD1/PDL1 antibodies, or depletion of immune-suppressor cells such as the negative regulatory T-cells (T_reg) or the myeloid derived suppressor cells (MDSC). This could lead to responses in distant metastases that are out of the light focus and may also inhibit recurrences due to activation of systemic anticancer immunity and long-term immune memory without the systemic autoimmune adverse effects often associated with immune checkpoint inhibitors.

The silicon phthalocyanine dyes according to the present invention can be detected or activated with red/NIR light that can penetrate deeper into tissue than light with a shorter wavelength. This makes diagnosis and therapy based on such dyes more effective, e.g. the diagnosis and therapy of skin diseases or superficial tumors (e.g. melanomas, esophageal, head and neck colon or urothelial tumors). Moreover, when bioconjugates, consisting of the dyes of the present invention linked to a molecule targeting tumor cells, are used e.g. in the operation field after surgical excision of a tumor it is of utmost importance that the NIR light can penetrate the tissue as deeply as possible in order to eliminate specifically remaining tumor cells that were not removed by surgery and that were targeted by the bioconjugate for complete removal of the tumor cells, avoidance of tumor recurrence and improved therapeutic outcome.

Moreover, the silicon phthalocyanine dyes according to the present invention having a maximal absorption wavelength of 795 nm might be preferred for specific clinical use. For example, light of about 800 nm wavelength has been shown to have maximum penetration through the cranium and into the brain, so that dyes with an appropriate absorption wavelength of about 800 nm are considered optimal for detection and therapy of lesions in the skull as well as in bones or in areas that are covered by bone. This particularly concerns the detection and treatment of brain tumors, bone metastases or lesions associated with neurodegenerative diseases.

The silicon phthalocyanines according to the present invention might also be used in a dual- labeled molecule targeting tumor cells (e.g. antibody or ligand), where the first label is the silicon phthalocyanine and the second label is a radioactive tracer for pre-, intra- and post- operative diagnosis and therapy. E.g. the radioactive tracer can be used for the diagnosis of the tumor, e.g. via positron emission tomography (PET), followed by PIT/PDT of the tumor. Alternatively, the silicon phthalocyanines according to the present invention in a dual-labeled molecule might be used for tumor diagnosis and the radioactive tracer for the following targeted radiotherapy.

List of frequently used abbreviations:

3:1 naphthalo-/phthalocyanine hybrid = tribenzophthalocyanine

APCI = atmospheric pressure chemical ionization

ESI = electrospray ionization

HRMS = high-resolution mass spectrum

IR = infrared

NIR = near-infrared

NMR = nuclear magnetic resonance

PDT = photodynamic therapy

PIT = photoimmunotherapy

PS = photosensitizer

PSMA = prostate-specific membrane antigen silicon phthalocyanines according to the invention = silicon phthalocyanines including 3:1 naphthalo-/phthalocyanine hybrids according to the invention silicon phthalocyanine dyes according to the invention = silicon phthalocyanine dyes including

3:1 naphthalo-/phthalocyanine hybrid dyes according to the invention siloxy = silyloxy

TPDT = targeted photodynamic therapy

US Patent 7,005,518 = X. Peng, D. R. Draney, J. Chen, Li-Cor Inc., Lincoln, Nebraska, Phthalocyanine Dyes, US-Patent 7,005,518 B2, February 28th, 2006. WO 2021/207691 = J. Betancourt, L Makings, T. Wiemann, R. Hoey, Rakuten Medical nc.,

San Mateo, California, Phthalocyanine Dye Compounds, Conjugates and Methods of Use Thereof, WO Application number 2021/207691 A1 , October 14th, 2021.

UV/VIS = ultraviolet and visible light

WB692-LB1 (for Wolf-Bruckner silicon phthalocyanine dye with λ_max = 692 nm, lysine-binding variant #1) = EMBODIMENT 1 (formula: Figure 1)

WB692-LB2 (for Wolf-Bruckner silicon phthalocyanine dye with λ_max = 692 nm, lysine-binding variant #2) = EMBODIMENT 2 (formula: Figure 1 )

WB692-CB1 (for Wolf-Bruckner silicon phthalocyanine dye with λ_max = 692 nm, cysteine- binding variant #1 ) = EMBODIMENT 3 (formula: Figure 1 )

WB692-CB2 (for Wolf-Bruckner silicon phthalocyanine dye with λ_max = 692 nm, cysteine- binding variant #2) = EMBODIMENT 4 (formula: Figure 1 )

WB795-LB1 (for Wolf-Bruckner 3:1 naphthalo-/phthalocyanine hybrid dye with λ_max = 795 nm, lysine-binding variant #1) = EMBODIMENT 5 (formula: Figure 2)

WB795-CB1 (for Wolf-Bruckner 3:1 naphthalo-/phthalocyanine hybrid dyes with λ_max = 795 nm, cysteine-binding variant #1 ) = EMBODIMENT 6 (formula: Figure 2)

Examples

The present invention is further illustrated by the following Examples and the Figures which represent preferred embodiments of the present invention:

I. Preparative Examples and Experimental Methods

1.1 Chemicals

Under a dry atmosphere of N₂, tetrahydrofuran (THF) was distilled over potassium, n-hexane likewise, and diethyl ether (Et₂O) over Na/K alloy. Dichloromethane (CH₂CI₂) and acetonitrile (MeCN) were distilled over CaH₂ under a dry atmosphere of N₂. Cyclohexane (C₆H₁₂) and ethyl acetate (EtOAc) for flash chromatography and workup were distilled using a rotary evaporator. Chloroform (CHCI₃), dichloromethane (CH₂CI₂), diethyl ether (Et₂O), methanol (MeOH), all for workup and/or flash chromatography, were purchased as "p.a. grade" and used without further purification. 1 .2 Laboratory hardware

Reactions were carried out in oven-dried (80°C) glassware. Chemicals were transferred under N₂atmosphere in plastic syringes, which were connected to oven-dried or packaged sterile steel cannulas. All apparatuses were used with a connection to a Schlenk line to prevent contact with water or air.

1 .3 Thin-layer chromatography

Thin-layer chromatography on Merck silica plates (TLC Silica gel 60 F254; supporting material = glass) served for monitoring reactions and assessing purification procedures. If possible, chromatograms were marked in UV light at 254 nm and subsequently stained using Ce(ll)stain [CeSO4 - 4 H₂O with molybdophosphoric acid (6.25 g) and cone. H₂SO₄ (15 mL) in H₂O (230 mL)]. For ionic compounds Merck C18 reversed-phase silica gel plates were used.

1 .4 Flash chromatography

Covalent compounds were purified by column chromatography in glass columns filled with silica gel as the solid phase, using compressed air for accelerating elution. Purification conditions are documented in the following style: (0 [cm], h [cm], F [mL], solvl :solv2 a:b, Fx- Fy); this means: A column with an inner diameter of 0 was packed with silica gel to a height of h. Fractions of the size F were collected. The product was eluted with the solvent solvl and solv2 in a ratio of a:b or, when a gradient of solvent mixtures was employed (solvl :solv2 a:b — > a’:b’), in ratios which are mentioned in the respective experiment. The fractions containing the product are specified as Fx-Fy.

Ionic compounds were purified in a Buchi flash machine consisting out of two pump modules C-605, a pump manager C-615, a UV photometer C-635, and a fraction collector C-660. The machine was charged with polypropylene cartridges prepacked either by Macherey-Nagel with reversed-phase silica gel (surface-modified with n-H₃₇C₁₈-SiCI₃; "Cis reversed-phase silica gel”) or by Interchim with reversed-phase silica gel (surface-modified with n-H₉-SiCI₃; "C₄ reversed phase silica gel”). Purification conditions are documented in the same style as detailed for purifications by flash chromatography on silica gel (cf. supra). 1 .5 Nuclear magnetic resonance spectroscopy

Nuclear magnetic resonance (from here "NMR") experiments were performed at the Institute for Organic Chemistry of the Albert-Ludwigs-Universitat Freiburg on a Broker DRX 500 MHz (¹H, ¹³C), a Bruker Avance II 400 MHz (¹H, ¹³C) or a Bruker Avance III 300 MHz (¹H, ¹³C). In the ¹H-NMR spectra the internal standard was residual protio-chloroform (CHCI₃: = 7.26 ppm). In ¹³C-NMR spectra CDCI₃was used as an internal standard (middle peak of the 3-line resonance has δ = 77.10 ppm). Other NMR solvents and the residual hydrogen equivalents therein, which served as the respective internal standard, were CD3OD (¹H [3.31 ppm], ¹³C [49.00 ppm]), D₂O (¹H [4.79 ppm]), C₆D₆(¹H [7.15 ppm], ¹³C [128.00 ppm]), and DMSO-d₆ (¹H [2.50 ppm], ¹³C [39.52 ppm]). All NMR spectra were processed and analyzed by Bruker’s program TopSpin. ¹H-NMR data are reported as follows: chemical shift (δ in ppm), multiplicity (s for singlet; d for doublet; t for triplet; m for multiplet; m_c for symmetrical multiplet; br for broad signal), coupling constant(s) (in Hz; ³ J couplings implied unless otherwise noted), integral (always complying with the assignment), and nucleus-specific assignment (referring to the numbers in the accompanying drawing; those may differ from the numbering which underlies the respective compound’s IUPAC name). All resonances - except AB signals - were interpreted as being due to first-order splittings; in AB signals, the high-field proton is denoted "A"' and the low-field proton "B". Integrate over the ¹H-NMR signals were consistent with our assignments. ¹³C NMR data are reported in terms of chemical shift (δ in ppm ) and nucleus- specific assignment (again, the numbering refers to that of the accompanying drawing and may differ from the numbering which underlies the respective compound’s IUPAC name).

1.6 Mass spectrometry

Mass spectrometry: High resolution mass spectra (from here "HRMSs") were recorded by C. Warth on a Thermo Scientific Exactive mass spectrometer equipped with an orbitrap (ion trap) analyzer. Ionization method: electrospray ionization (from here "ESI"; spray voltage: 2.5- 4.0 kV) or atmospheric pressure chemical ionization (from here "APO"; spray current: 5 pA).

1.7 Syntheses of EMBODIMENT 1 (= silicon phthalocyanine WB692-LB1 ) and EMBODIMENT 2 (= silicon phthalocyanine WB692-LB2); [the corresponding reactions are visualized in Figures 3 - 6] Preparation 1 : 4-(4-lodophenoxy)phthalodinitrile (1)

4-Nitrophthalodinitrile (3; 15.0 g, 86.6 mmol), K₂CO₃ (89.80 g, 649.8 mmol, 7.5 equiv.) and 4-iodophenol (28.6 g, 130 mmol, 1.5 equiv.) were dissolved in DMF (420 mL). The resulting mixture was stirred for 32 h. Saturated aqueous NH4CI (200 mL) and H₂O (500 mL) were added. Extraction with Et₂O (5 x 250 mL) followed. The combined organic phases were washed with aq. NaOH (2 M, 1 × 100 mL, 2 × 50 mL) and dried over Na₂SO₄ All volatiles were removed under reduced pressure. This gave the title compound (1; 28.3 g, 81.8 mmol, 94%) as a colorless solid.

Preparation 2: 5-(4-lodophenoxy) isoindoline-1, 3-diimine (5)

4-(4-lodophenoxy)phthalodinitrile (1; 14.94 g, 43.16 mmol) was dissolved in MeOH (100 mL). NaOMe was added (2.09 g, 38.9 mmol, 0.9 equiv.). The resulting mixture was heated at 50°C. A saturated solution of NH₃ in MeOH (150 mL) was added. The resulting mixture was refluxed for 2 h. All volatiles were removed under reduced pressure. H₂O (100 mL) was added. The precipitate was filtered off. It was dried over KOH in vacuo. This delivered the title compound (5) as a slightly greenish solid (15.18 g, 41.79 mmol, 96%). Preparation 3: lsoindoline-1 ,3-diimine (6)

NaOMe (15 g, 27 mmol, 0.70 equiv.) was dissolved in MeOH (400 mL). The resulting mixture was heated at 50°C. Phthalodinitrile (4; 50.0 g, 390 mmol) was added. The resulting mixture was heated under reflux. A solution of NH₃ in MeOH (200 mL, 7M, 1.40 mol, 3.6 equiv.) was added. Heating under reflux was continued for 2.5 h. All volatiles were removed under reduced pressure. H₂O (200 mL) was added. A precipitate formed. It was filtered off 30 min later. It was washed with H₂O (150 mL) and dried over KOH in vacuo for 2 d. The title compound (6) resulted as a slightly blue solid (38.96 g, 268.4 mmol, 69%). There was no need for further purification.

Preparation 4: Methyl 3,4,5-Tris[(prop-2-yn-1-yl)oxy]benzoate (10)

Methyl gallate (7; 1.513 g, 8.216 mmol) and K₂CO₃ (5.64 g, 40.8 mmol, 4.96 equiv.) were dissolved in DMF (22 mL). Propargyl bromide (80% in toluene, 6.0 mL, 6.408 g pure, 53.86 mmol) was added dropwise. The resulting mixture was stirred for 5 d. Half-saturated aqueous NH4CI (50 mL) and Et₂O (50 mL) were added. The layers were separated. The aqueous layer was extracted with Et20 (4 × 50 mL). The combined organic layers were washed with brine (2 × 20 mL) and dried over Na2SO4. All volatiles were removed under reduced pressure and the residue was purified by flash chromatography on silica gel [0 - 3.5 cm, h = 14 cm, F = 50 mL, c-C₆H₁₂EtOAc 90:10, from F15 80:20] . F25-36 delivered the title compound (10) as a colorless solid (2.399 g, 8.046 mmol, 97%). Purification of larger quantities of 10 can be realized by crystallization from c-C₆H₁₂EtOAc or MeOH, which resulted in slightly lower yields (86-89%). Preparation 5: (3,4,5-Tris[{prop-2-yn-1-yl}oxy]phenyl)methanol (9)

The benzoate 10 (8.00 g, 26.82 mmol) was dissolved in THF (280 mL). LiAIH₄ (3.70 g, 97.5 mmol, 3.64-fold molar amount) was suspended in THF (150 mL). As a first portion, 50 mL of this suspension was added dropwise to the solution of 10. The reaction mixture was cooled to 0°C. The remainder of the suspension of the reductant was added. An extra portion of LiAIH₄ (4.50 g,119 mmol, 4.42-fold molar amount) was suspended in THF (200 mL) and added as well. The reaction mixture was warmed to room temp, and stirred for 7 h. It was cooled to 0°C. H₂O (8 mL) was added carefully followed by an aqueous solution of NaOH (15%, 8 mL) and pure H₂O (32 mL). MgSO₄was added MgSO₄ or taking up the excess water. The resulting mixture was filtered. The filter cake was triturated with Et₂O (300 mL). The combined filtrates were liberated from volatile material under reduced pressure. This delivered the title compound (9) as a colorless solid (6.528 g, 24.15 mmol, 90%).

Preparation 6: Sodium 3-azidopropane-1 -sulfonate (12)

Propanesultone (2.82 g, 23.1 mmol) and NaN₃ (3.00 g, 46.2 mmol, 2.0 equiv.) were dissolved in 1 ,4-dioxane and H₂O (25 mL, v:v = 1 :1). The resulting mixture was stirred at room temp, for 3 d. All volatiles were removed under reduced pressure. The residue was suspended in a mixture of EtOH (25 mL) and H₂O (1 mL). The resulting mixture was stirred under reflux. A suspension resulted which was filtered hot. The filtrate was evaporated under reduced pressure. This gave the title compound (12) as a colorless solid (3.74 g, 19.9 mmol, 86%). Preparation 7: 29,31-(Dichlorosilanediyl)-2-(4-iodophenoxy)-29H,31H-silicon phthalocyanine (8) and 29,31-Bis{[3,4,5-tris(prop-2-yn-1-yloxy)phenyl]methoxy}silanediyl-2-(4-iodophenoxy)-

29H,31H-silicon phthalocyanine (11)

The diiminoisoindolines 5 (1.00 g, 2.75 mmol) and 6 (3.20 g, 22.0 mmol, 8.0 equiv.) were suspended in quinoline (40 mL). Under an atmosphere of N₂, SiCU (2.80 mL, 4.14 g, 24.4 mmol, 8.86 equiv.) was added dropwise. The resulting mixture was heated under reflux for 1.5 h. The reaction mixture was cooled to 120°C and then filtered. The residue was washed with CH₂CI₂ (2 × 25 mL). The filtrate was diluted with toluene (250 mL), refluxed, and filtered hot. The residue was washed with acetone (20 mL) to deliver a dark blue solid (1.66 g); it contained the expected mixture of the monosubstituted, i. e. A₃B-type silicon phthalocyanine

8 (desired) and its unsubstituted analog 29,31-Bis{[3,4,5-tris(prop-2-yn-1- yloxy)phenyl]methoxy}silanediyl-29H,31H-silicon phthalocyanine, i. e. the A₄-type parent- silicon phthalocyanine (undesired, not depicted).

Such a "crude silicon phthalocyanine 8" (1.60 g, ≤1.93 mmol), K₂CO₃ (1.653 g, 11.96 mmol, >6.20 equiv.) and the benzyl alcohol 9 (2.69 g, 9.97 mmol, >5.17 equiv.) were suspended in toluene (120 mL). The resulting mixture was heated under reflux for 5 h. It was cooled to room temp, and filtered over a pad of silica. The filter cake was triturated with EtOAc (500 mL) and then discarded. All volatiles were removed from the filtrate under reduced pressure. The resulting residue was purified by flash chromatography on silica gel [∅ = 5.5 cm, h = 18 cm, F = 70 mL, toluene:EtOAc 96:4, from F24 94:6]. This delivered (F26-F47) a crude material containing the title silicon phthalocyanine (11) admixed with a small amount of the unsubstituted, i. e. A₄-type silicon phthalocyanine. A second purification by flash chromatography on silica gel [∅ = 3.0 cm, h = 21 cm, F = 60 mL, c-C₆H₁₂EtOAc 85:15, from F30 80:20] delivered (F43-54) the title compound (11) as a dark green solid (0.4925 g, 0.3797 mmol, 13%).

Preparation 8: 2-(4-lodophenoxy)-29,31-bis[(3,4,5-tns{[1-(sodium 3-sulfonatopropyl)-1,2,3- triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H,31H-silicon phthalocyanine (13)

The silicon phthalocyanine 11 (300 mg, 231 μmol), sodium 3-azidopropane-1 -sulfonate (12; 433 mg, 2.31 mmol, 10 equiv.) and PPh₃ (38.5 mg, 147 μmol, 63 mol-%) were dissolved in DMSO (3 mL). Cul (25.7 mg, 135 μmol, 58 mol-%) was added and then NEt₃ (0.6 mL) was added dropwise. The resulting mixture was stirred for 24 h. It was added dropwise to acetone (14 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (15 mL) and purified by flash chromatography on "C₁₈ reversed-phase silica gel" [0 = 2.0 cm, h = 15 cm, F = 20 mL, 25 mL/min, 10 mM HNEt₃ ^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 85:15 to 70:30 in 15 min]. The collected fractions (F14-18) were concentrated under reduced pressure and the resulting solution was freeze dried. The residue was dissolved in H₂O (4 mL). The resulting solution was added dropwise to a saturated solution of Nal in acetone (15 mL). A precipitate was formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (10 mL), dissolved in H₂O (10 mL), and freeze-dried to deliver the title compound (13) as a green solid (0.4429 g, 0.1830 mmol, 79%).

Preparation 9: 2-[4-(4-Hydroxybut-1-ynyl)phenoxy]-29,31-bis[(3,4,5-tris{[1-(sodium 3- sulfonatopropyl) -1,2, 3-triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H, 31 H -silicon phthalocyanine (14)

The silicon phthalocyanine 13 (0.100 g, 41.3 μmol) and (meta-NaO₃S-H₄C₆)₃P (6.00 mg, 10.3 μmol, 25 mol-%) were dissolved in degassed H₂O (3 mL). Pd(OAc)₂ (10 mM in MeCN, 0.2 mL, 2 μmol, 5 mol-%), Cul (10 mM in MeCN, 0.4 mL, 4 μmol, 10 mol-%), and NEt3(0.6 mL) were added. But-3-yn-1-ol (0.5 M in degassed H₂O, 0.82 mL, 41 mmol, 10 equiv.) was added dropwise during 5 h. The resulting mixture was stirred at room temp, for 16 h. Nal (0.3 g) was added. The resulting mixture was added dropwise to acetone (15 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was purified by flash chromatography on "C₁₈ reversed-phase silica gel" [0 = 2.0 cm, h = 15 cm, F = 20 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 85:15 75:25 in 20 min]. The collected fractions (F15-25) were concentrated under reduced pressure. The resulting solution was freeze-dried. The resulting residue was dissolved in aqueous Nal (10 weight-%, 1 mL). The resulting solution was added dropwise to acetone (15 mL). A precipitate formed. It was centrifuged, washed with acetone (15 mL) and dissolved in H₂O (6 mL). The solution was freeze-dried to deliver the title compound (14) as a green solid (0.76 g, 0.032 mmol, 78%).

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C₉₂ ¹H₈6¹⁴N₂6¹⁶O₂8³²S6²⁸Si]^6- (tantamount to z = 6) with m/z = 370.5709 which deviates from the calculated m/z = 370.4039 by -0.21 ppm.

¹H NMR (500.42 MHz, DMSO-d₆): 8 = AB signal (& = -0.73, & = -0.70, ²J_A,B = 14.3 Hz, 4H, 2 × SiOC-H₂R), 1.97-2.07 (tt, ³J₂;₃- = = ³J₂-,r = 6.8 Hz, 4H, B: 2 × 2’-H₂), 2.09-2.21 (m_c, 8H, A: 4 × 2’-H₂), 2.39-2.44 (m_c, 4H, B: 2 × 3’-H₂), 2.47-2.50 (m overlapping with DMSO-d₆-Signal, 8H, B: 4 × 3'-H₂), 2.65 (t, ³J_3,4 = 6.8 Hz, 2H, C: 3-H₂), 3.64 (s overlapping with signal of C: 4- H₂, 4H, 4 × 2”-H), 3.67 (t overlapping with signal of 2”-H₂, ³J₄,₃ = 6.8 Hz, 2H, C: 4-H₂), 3.92 (s, 8H, A: 4 × I-H₂), 4.38 (t, ³ J_{1, 2} = 6.8 Hz, 4H, B: 2 × 1’-H₂), 4.48 (t, ³ J₁, ₂' = 6.8 Hz, 8H, A: 4 × 1 ’-H₂), 4.58 (s, 4H, B: 2 × 1-H₂), br. s (5.01 , 1 H, C: 4-OH), 7.41 (m_c, 2H, 2 × 2’-H), 7.57 (m_c, 2H, 2 × 3’-H), 7.76 (s, 2H, B: 2 × 3 H), 7.98 (s, 4H, A: 4 × 3-H), 8.10 (d, ^orthoJ_3,4 = 8.1 Hz, 1 H, 3-H) 8.38-8.51 (m, 6H, 6 × β -H = 9-H, 10-H, 16-H, 17-H, 23-H, 24-H), s (9.04, 1H, 1-H), 9.54-9.69 ppm (m, 7H, 7 x _ff-H = 4-H, 8-H, 11-H, 15-H, 18-H, 22-H, 25-H).

¹³C NMR (125.85 MHz, DMSO-d₆): 8 = 23.38 (C: C-3), 26.38 (B: 2 × C-2’), 26.43 (A: 4 × C-2’), 47.96 (B: 2 × C-3’), 48.02 (A: 4 × C-3’), 48.42 (B: 2 × C-1), 48.55 (A: 4 × C-1’), 57.43 (2 × SiOCH₂R), 59.86 (C: C-4), 60.85 (A: C-1 ), 65.69 (B: C-1 ), 80.58 (C: C-1), 88.50 (C: C-2), 101.23 (C-2”), 111.21 (C-1 ), 119.50 (C-4’), 119.97 (C-2’), 123.34 (C-3), 123.47 (C-X), 123.57 (C-X), 123.67 (C-X), 124.11 (A: C-3), 124.14 (B: C-3), 125.75 (C-X), 130.23 (C-X), 131.98 (C-X), 132.05 (C-X), 132.11 (C-X), 133.59 (C-3’), 134.04 (C-4”), 134.67 (C-1”), 134.87 (C-X), 134.93 (C-X), 135.02 (C-X), 135.05 (C-X), 136.98 (C-X), 142.14 (A: C-2), 143.52 (B: C-2), 148.00 (C-X), 148.57 (C-X), 148.60 (C-X), 148.80 (C-X), 148.97 (C-X), 149.24 (C-X), 149.28 (C-X), 150.19 (C-3”), 155.71 (C-1 ’), 160.11 ppm (C-X). Resonances which are attributed to nuclei denoted as "C-X" could not be assigned more specifically based on 1 D-NMR data alone. Altogether, compound 14 contains ¹³C nuclei in potentially as many as 57 different chemical environments. We detected (and listed above) 48 different ¹³C-NMR resonances.

Preparation 10: 2-({4-[(lmidazol-1-yl)carbonyloxy]but-1-ynyl}phenoxy)-29,31-bis[(3,4,5-tris{[1- (sodium 3-sulfonatopropyl)-1 , 2, 3-triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H, 31 H- silicon phthalocyanine (15)

The silicon phthalocyanine 14 (100 mg, 42.3 μmol ) was dissolved in DMSO (1.5 mL). Carbonyldiimidazole (68.0 mg, 423 μmol, 10 equiv.) was added. The atmosphere was exchanged with N₂. Pyridine (0.5 mL) was added and the resulting mixture was stirred at 70°C for 5.5 h. It was cooled to room temp, was added dropwise to a saturated Nal-solution (8 mL) in acetone. A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (2 × 10 mL). It was dried in vacuo to deliver the title compound (15) as a slightly impure green solid (97.7 mg, 39.8 μmol, 94%). HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C96¹H₈8¹⁴N₂₈ ¹⁶O29³²S₆ ²⁸Si]^6e (tantamount to z = 6) with m/z = 386.0731 which deviates from the calculated m/z - 386.0733 by -0.64 ppm.

Preparation 11 : 2-[4-({[(5-Carboxylpentyl)amino]carbonyloxy}but-1-ynyl)phenoxy]-29,31- bis[(3, 4, 5-tris{[ 1 -(sodium 3-sulfonatopropyl)- 1, 2, 3-triazol-4-yl]methoxy}phenyl)methoxy]- silanediyl-29H,31H-silicon phthalocyanine (16)

The silicon phthalocyanine 15 (25.0 mg, 10.2 μmol) was dissolved in DMSO (0.2 mL). Pyridine (0.1 mL) and sodium 6-aminohexanoate (0.7 M in H₂O, 60pL, 6.5 mg, 42 μmol, 4.2 equiv.) was added. The resulting mixture was stirred at room temp, for 21 h. It was added to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (10 mL). It was purified by flash chromatography on "C₄ reversed-phase silica gel” [0 = 2.0 cm, h = 14 cm, F = 20 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 — > 70:30 in 28 min]. Fractions 25-27 were concentrated under reduced pressure. The resulting solution was freeze-dried. The solid which resulted was dissolved in H₂O and precipitated by pouring into a saturated solution of Nal in acetone (8 mL). This precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (8 mL) and thereafter dissolved in H₂O (4 mL) and freeze-dried. This delivered the title compound (16) as a green solid (10 mg, 3.9 μmol, 38%).

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C9₉ ¹H₉₇ ¹⁴N₂7¹⁶O3i³²S6²⁸Si]^6e (tantamount to z = 6) with m/z = 396.5825 which deviates from the calculated m/z = 396.5828 by -0.80 ppm.

Preparation 12: 2-({[({6-[(2,5-Dihydro-1H-2,5-dioxopyrrol-1-yl)oxy]-6-oxohex-1-yl}amino)- carbonyloxy]but-1-ynyl}phenoxy)-29, 31 -bis[(3, 4, 5-tris{[ 1 -(sodium 3-sulfonatopropyl)- 1, 2, 3-tri- azol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H, 31 H -silicon phthalocyanine

(EMBODIMENT 1 = WB692-LB1)

The silicon phthalocyanine 16 (10.0 mg, 3.93 μmol) was dissolved in DMSO (0.2 mL). Disuccinimidyl carbonate (1 .8 mg, 7.0 μmol, 1.8 equiv.) was added. The resulting mixture was heated at 60°C for 1.5 h. Additional disuccinimidyl carbonate (3.8 mg, 14 μmol, 3.8 equiv.) was added. Stirring at 60°C was continued for 5 min. After cooling to room temp., the reaction mixture was added dropwise to a saturated solution of Nal in acetone. This caused the reaction product to precipitate. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (8 mL). All volatiles were removed under reduced pressure to deliver the title compound (EMBODIMENT 1 = WB692- LB1) as an impure green solid (12 mg, "116%'').

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C₁₀₃ ¹H₁₀0¹⁴N₂₈ ¹⁶O₃₃ ³²S₆ ²⁸Si]^6e (tantamount to z = 6) with m/z = 412.7520 which deviates from the calculated m/z = 412.7522 by ”0.60 ppm.

Preparation 13: 2-(4-[4-({[7-oxo-7-(perf/uorophenoxy)heptyl]carbamoyl}oxy)but-1-yn-1- yl]phenoxy)-29,31-bis[(3,4,5-tris{[1 -(sodium 3-sulfonatopropyl)-1,2,3-triazol-4- yl]methoxy}phenyl)methoxy]silanediyl-29H,3W-silicon phthalocyanine (EMBODIMENT 2 = WB692-LB2) The silicon phthalocyanine 16 (20 mg, 7.9 μmol) and bis(pentafluorophenyl) carbonate (31.3 mg, 79.4 μmol, 10 equiv.) were dissolved in a mixture of DMSO (0.4 mL) and pyridine (0.2 mL). The resulting solution was stirred at 50°C for 4 h. It was cooled to room temp, and added to a saturated solution of Nal in acetone (8 mL). A precipitated formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (3 x 10 mL). Evaporation of excess acetone under reduced pressure delivered the title compound (EMBODIMENT 2 = WB692-LB2) as a somewhat impure green solid (15.5 mg, 5.77 μmol, 72%).

HRMS (neg. ion mode ESI): [M - 3 x Na®] observed as

[¹³C¹²Ci04¹H96¹⁴N₂7¹⁶O3i¹⁹F5³²S6²³Na3²⁸Si]^3e (tantamount to z = 3) with m/z = 871.8174 which deviates from calculated m/z = 871.8174 by -0.03 ppm.

1.8 Synthesis of silicon phthalocyanines 17, 18, 19, 20, and 21. All of them differ from the key intermediate silicon phthalocyanine 13 concerning the axially substitution and are water- soluble (see Figure 7). The appropriate silicon phthalocyanine analogue of 11 containing six alkyne moieties (128.4 mg, 96.89 μmol) was dissolved in DMSO. Cul (11.1 mg, 58.1 μmol, 60 mol-%), PPh₈ (16.2 mg, 62.0 μmol, 64 mol-%), NEt₈ (0.5 mL), and sodium 3-azidopropane-1 -sulfonate (12; 145 mg, 0.775 mol, 8 equiv.) were added. This mixture was stirred for 17 h. The reaction mixture was added dropwise to a solution of Nal (4 g) in acetone (40 mL). The resulting precipitate was centrifuged, the supernatant liquid was decanted. The remaining pellet was washed with acetone (40 mL) and purified by flash chromatography on "C₄ reversed-phase silica gel" [0 = 2.0 cm, h = 15 cm, F = 20 mL, 30 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 80:20 in 1 min, 80:20 -> 60:40 in 12 min, 60:40 10:90 in

5 min]. The collected fractions (F11-14) were freeze dried. The residue was dissolved in a minimum amount of H₂O and added dropwise to a saturated Nal solution in acetone (10 mL). The resulting precipitate was centrifuged and the supernatant liquid was decanted. The remaining pellet was washed with acetone (10 mL) and all volatiles were removed under reduced pressure to deliver the title compound 17 as a green solid (167 mg, 68.3 μmol, 71%) contaminated by traces of an unknown silicon phthalocyanine compound.

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹³C¹²C₈9¹H₈₅ ¹⁴N₂₆ ¹⁶O₂₇ ³²S₆ ²⁸Si¹²⁷l]^6e (tantamount to z = 6) with m/z = 384.8880 which deviates from calculated m/z = 384.8880 by -0.09 ppm

Preparation 15: 2-(4-lodophenoxy)-29,31-bis[(3,5-bis{[1-(sodium 3-sulfonatopropyl)-1 ,2,3- triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H,31H-silicon phthalocyanine (18)

The appropriate silicon phthalocyanine analogue of 11 containing four alkyne moieties (328.6 mg, 276.4 μmol), PPha (32 mg, 0.12 mmol, 44 mol-%), and Cul (21.1 mg, 111 μmol, 40 mol-%) were dissolved in DMSO (4 mL). NEts (0.5 mL) and sodium 3-azidopropane-1- sulfonate (12; 310 mg, 1.66 mol, 6 equiv.) were added. The resulting mixture was stirred for 24 h. The reaction mixture was added dropwise to a solution of Nal (3 g) in acetone (43 mL) and H₂O (2 mL). A precipitate formed, which was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (45 mL) and purified by flash chromatography on "C₁ 8 reversed-phase silica gel" [0 = 5.5 cm, h = 15 cm, F = 20 mL, 90 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 —> 80:20 in 6 min, 80:20 — > 74:26 in 2 min, 74:26 —» 60:40 in 15 min]. The collected fractions (F57-66) were freeze dried. The residue was dissolved in a minimum amount of H₂O and added dropwise to a saturated Nal solution in acetone (45 mL). The resulting precipitate was concentrated as a pellet by centrifugation, the supernatant liquid was decanted and the remaining pellet was washed with acetone (45 mL). All volatiles were removed under reduced pressure to deliver the title compound 18 as a green solid (178.8 mg, 92.28 μmol, 33%). HRMS (neg. ion mode ESI): [M - 4 × Na®] observed as [¹²C₇6¹H65¹⁴N₂o¹⁶0₁₉ ³²S4²⁸Si¹²⁷l]^4e (tantamount to z = 4) with m/z = 461.0623 which deviates from calculated m/z = 461.0613 by +2.12 ppm

The appropriate silicon phthalocyanine analogue of 11 containing four alkyne moieties (200 mg, 187 μmol), sodium 3-azidopropane-1 -sulfonate (12; 209 mg, 1.12 mol, 6 equiv.), PPhs (31.3 mg, 120 μmol, 64 mol-%), and Cul (21.3 mg, 135 μmol, 60 mol-%) were dissolved in DMSO (3 mL). NEt3 (0.5 mL) was added and the resulting mixture was stirred for 19 h. The reaction mixture was added dropwise to acetone (20 mL). Nal (2 g), H₂O (4 mL), and acetone (21 mL) were added. The resulting precipitate was concentrated as a pellet by centrifugation and the supernatant liquid was decanted. The residue was washed with acetone (45 mL) and purified by flash chromatography on "C₁ 8 reversed-phase silica gel" [0 = 4.0 cm, h = 17 cm, F = 20 mL, 90 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 for 2 min, 90:10 80:20 in 10 min, 80:20 -> 60:40 in 10 min]. The collected fractions (F49-71 ) were freeze dried. The residue was dissolved in a minimum amount of H₂O and added dropwise to a saturated Nal solution in acetone (15 mL). Acetone (30 mL) was added and the resulting precipitate was concentrated as a pellet by centrifugation, the supernatant liquid was decanted and the remaining pellet was washed with acetone (45 mL). All volatiles were removed under reduced pressure to deliver the title compound 19 as a green solid (192 mg, 106 μmol, 57%).

HRMS (neg. ion mode ESI): [M - 4 × Na®] observed as [¹²C70¹H₅5¹⁴N₂2¹⁶Oi₅ ³²S₄ ²⁸Si¹²⁷l]^4e (tantamount to z = 4) with m/z = 431.5474 which deviates from calculated m/z = 431 .5484 by -2.26 ppm

Preparation 17: 2-(4-lodophenoxy)-29,31-bis[(3,4-bis{[1 -(sodium 3-sulfonatopropyl)- 1,2,3- triazol-4-yl]methoxy}phenyl)methoxy]silanediyl~29H,3W-silicon phthalocyanine (20)

The appropriate silicon phthalocyanine analogue of 11 containing four alkyne moieties (280.0 mg, 235.5 μmol) was dissolved in DMSO (4 mL). Cul (18.0 mg, 94.2 pmol, 40 mol-%), PPh3 (27.2 mg, 104 μmol, 44 mol-%), NEts (0.5 mL), and sodium 3-azidopropane-1 -sulfonate (12; 264 mg, 1 .41 mmol, 6 equiv.) were added. The resulting mixture was stirred for 21 h. The reaction mixture was added dropwise to a solution of Nal (2 g) in acetone (45 mL). H₂O (2 mL) was added. The resulting precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted, the residue washed with acetone (45 mL) and purified by flash chromatography on "C₁ 8 reversed-phase silica gel" [0 = 5.5 cm, h = 15 cm, F = 20 mL, 90 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), HzO:MeCN 90:10 for 1 min, 90:10 -> 80:20 in 1 min, 80:20 — > 60:40 in 12 min, 60:40 -> 30:70 in 5 min, 30:70 for 5 min]. The collected fractions (F52-62) were freeze dried. The residue was dissolved in a minimum amount of H₂O and added dropwise to a saturated Nal solution in acetone (40 mL). The resulting precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted and the residue was washed with acetone (40 mL). All volatiles were removed under reduced pressure to deliver the title compound 20 as a green solid (102 mg, 52.6 μmol, 22%) contaminated by traces of an unknown silicon phthalocyanine compound.

HRMS (neg. ion mode ESI): [M - 4 × Na®] observed as [¹³C¹²C₇₅ ¹H6₅ ¹⁴N₂0¹⁶Oi9³²S₄ ²⁸Si¹²⁷l]^4e (tantamount to z = 4) with m/z = 461.3122 which deviates from calculated m/z = 461.3122 by +0.10 ppm

Preparation 18: 2-(4-lodophenoxy)-29,31-bis[2,2-bis{[1 -(sodium 3-sulfonatopropyl)-1,2,3- triazol-4-yl]methyl}ethoxy]silanediyl-29H,31H-silicon phthalocyanine (21 )

The appropriate silicon phthalocyanine analogue of 11 containing four alkyne moieties (114 mg, 114 μmol) was dissolved in DMSO (2 mL). Cul (8.7 mg, 46 μmol, 40 mol-%), sodium 3-azidopropane-1 -sulfonate (12; 127 mg, 0.683 mmol, 6 equiv.), PPhs (13.1 mg, 50.1 μmol, 44 mol-%), and NEts (0.5 mL) were added. The resulting mixture was stirred for 16 h. The reaction mixture was added dropwise to a solution of Nal (2 g) in acetone (45 mL). H₂O (2 mL) was added. The resulting precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted, the residue washed with acetone (45 mL) and purified by flash chromatography on "C₁ 8 reversed-phase silica gel” [0 = 5.5 cm, h = 15 cm, F = 20 mL, 90 mL/min, 10 mM HNEts^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 for 1 min, 90:10 —► 80:20 in 2 min, 80:20 — ► 70:30 in 5 min, 70:30 for 5 min, 70:30 —> 40:60 in 5 min]. The collected fractions (F40-45) were freeze dried. The residue was dissolved in a minimum amount of H₂O and added dropwise to a saturated Nal solution in acetone (40 mL). The resulting precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted and the residue was washed with acetone (40 mL). All volatiles were removed under reduced pressure to deliver the title compound 21 as a blue solid (87.4 mg, 50.0 pmol, 44%). HRMS (neg. ion mode ESI): [M - 4 × Na®] observed as [¹²C₆6¹H₆i¹⁴N₂₀ ¹⁶Oi₅ ³²S4²⁸Si¹²⁷l]^4e (tantamount to z = 4) with m/z = 414.0588 which deviates from calculated m/z = 414.0586 by +0.50 ppm

1.9 Synthesis of EMBODIMENT 3 (= silicon phthalocyanine WB692-CB1 ; the corresponding reactions are visualized - or referred to - in Figure 8)

Preparation 19: 6-(2,5-Dioxo-2,5-dihydro-1^-pyrrol-1-yl)hexanoic acid (23)

23

6-Aminohexanoic acid (2.00 g, 15.3 mmol) and maleic anhydride (1.50 g, 15.3 mmol, 1.0 equiv.) were dissolved in AcOH (40 mL). After 30 min a colorless precipitate had formed. The resulting suspension was heated under reflux for 16 h. It was cooled to room temperature. All volatiles were removed under reduced pressure. The resulting residue was dissolved in EtOAc (50 mL) and CH₂CI₂ (150 mL). It was washed with HCI (4 M, 20 mL) and H₂O (20 mL). The organic layer was dried over Na₂SO4. All volatiles were removed under reduced pressure. This delivered the title compound (23; 2.69 g, 12.7 mmol, 83%) sufficiently pure.

Preparation 20: 1-(5-lsocyanatopentyl)-1H-pyrrole-2, 5-dione (22)

22

The carboxylic acid 23 (300 mg, 1.42 mmol) was dissolved in CH₂CI₂ (10 mL). (COCI)₂ (0.38 ml, 0.56 g, 4.4 mmol, 3.1 equiv.) was added dropwise. The resulting mixture was stirred at room temp, for 16 h. All volatiles were removed under reduced pressure. The residue was dissolved in MeCN (5 mL). NaNa (92.3 mg, 1.42 mmol, 1.0 equiv.) was added. The reaction mixture was stirred vigorously at room temp, for 2 h and at 70°C for another 2 h. It was cooled to room temp, and filtered over celite and silica. The filter cake was triturated with CH₂CI₂ (5 mL) and then discarded. All volatiles were removed from the filtrate under reduced pressure, leaving behind the title compound (22) as a slightly yellow oil (0.308 g, 1.34 mmol, 94%) almost pure (yet susceptible to decompose when being stored). Purification by flash chromatography on silica gel [0 = 2 cm, h = 27 cm, F = 20 mL, c-C₆H₁₂EtOAc 75:25] delivered (F9-13) the title compound (22) as a colorless solid (0.122 g, 0.531 mmol, 37%).

Preparation 21 : 2-[({5-[( 1H-2,5-Dioxopyrrol-1-yl)pent-1-yl]amino]carbonyloxy)}but-1-yn- yl)phenoxy]-29, 31 -bis[(3, 4, 5-tris{[ 1 -( sodium 3-sulfonatopropyl) - 1, 2, 3-triazol-4-yl]methoxy}- phenyl)methoxy]silanediyl-29H,31H-silicon phthalocyanine (EMBODIMENT 3 = WB692-CB1)

The silicon phthalocyanine 14 (58.7 mg, 24.8 pmol) and the isocyanate 22 (23.0 mg, 110 μmol, 4.46 equiv.) were dissolved in DMF (2.0 mL). MoO2d₂(DMF)2 (1.0 mg, 2.9 μmol, 12 mol-%,) was added. The resulting mixture was stirred at room temp, for 3 h. Additional amounts of isocyanate 22 (26.0 mg, 125 μmol, 5.04 equiv.) and MoO₂Cl2(DMF)₂ (3.0 mg, 8.7 μmol, 35 mol-%) were added. Stirring at room temp, was continued for 16 h. An aqueous solution of Nal [10% (w:w), 2 mL] was added. The resulting mixture was added to pure acetone (12 mL) forming a precipitate. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (8 mL). It was purified by flash chromatography on "Cw reversed-phase silica gel" [0 = 2.0 cm, h = 15 cm, F = 20 mL, 25 mL/min, 10 mM HNEts^+-OAc (which buffered at pH = 7.0), HzCLMeCN 80:20 —>■ 70:30 in 17 min]. The fractions (F13-F20) were concentrated under reduced pressure. The resulting solution was freeze-dried. The residue was dissolved in an aqueous solution of Nal [10% (w:w), 1 mL]. The resulting solution formed a precipitate when it was added to pure acetone (12 mL). This precipitate was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone. It was dissolved in H₂O whereupon freeze-drying delivered the title compound (EMBODIMENT 3 = WB692-CB1) as a green solid (7.5 mg, 2.9 μmol, 12%).

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²Ci02¹Hg8¹⁴N₂8¹⁶O3i³²S6²⁸Si]^6e (tantamount to z = 6) with m/z = 405.0848 which deviates from the calculated m/z = 405.0847 by +0.31 ppm.

1.10 Synthesis of EMBODIMENT 4 (= silicon phthalocyanine WB692-CB2; the corresponding reactions are visualized - or referred to - in Figure 9)

Preparation 22:

25

Phthalimide (1.946 g, 13.23 mmol) and PPhs (3.47 g, 13.2 mmol, 1.0 equiv.) were dissolved in THF (60 mL). But-3-yn-1-ol (1.00 mL, 0.927 g, 13.2 mmol, 1.0 equiv.) and diisopropyl azodicarboxylate (2.60 mL, 2.67 g, 13.2 mmol, 1.00 equiv.) was added dropwise. The resulting mixture was stirred for 3 d at room temperature. All volatiles were removed under reduced pressure. The solid residue was suspended in CH₂CI₂ (10 mL). The resulting suspension was applied to flash chromatography on silica gel [0 = 4.0 cm, h = 20 cm, F = 50 mL, c-C₆Hi2:EtOAc 17:83, from F1825:75], F10-16 delivered the title compound (25) as a colorless solid (2.144 g, 10.76 mmol, 81 %). Preparation 23:

Phthalimid 25 was dissolved in MeOH (12 mL). Hydrazine hydrate (0.16 mL, 0.17 g, 3.3 mmol, 1 .3 equiv.) was added dropwise. The resulting mixture was stirred for 24 h. A solid precipitated. It was filtrated and rinsed off with MeOH (8 mL). The filtrate was acidified with 1M HCI until pH = 1 was reached. A solid precipitated. It was collected by centrifugation. The solid was suspended in H₂O (10 mL) and the resulting suspension was filtrated. The filtrate was evaporated under reduced pressure to deliver the title compound (24) as a slightly yellow solid (0.192 g, 1.82 mmol, 72%).

Preparation 24: 2-[4-(4-Aminobut-1-ynyl)phenoxy]-29,31-bis[(3,4,5-tris{[1-(sodium 3- sulfonatopropyl)- 1, 2, 3-triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H, 31H-silicon phthalocyanine (26)

The silicon phthalocyanine 13 (0.080 g, 33.06 μmol) and (meta-NaO₃S-H₄C₆sP (4.7 mg,

8.3 μmol, 25 mol-%) were dissolved in degassed H₂O (3 mL). Pd(OAc)₂ (16 mM in MeCN, 0.10 mL, 1.7 μmol, 5 mol-%), Cul (16 mM in MeCN, 0.1 mL, 1.7 μmol, 5 mol-%), and NEts (0.4 mL) were added. A solution of But-3-in-1-amin hydrochlorid (34.9 mg, 331 μmol, 10 equiv.) in degassed H₂O (1.0 mL) was added dropwise during 5 h. The resulting mixture was stirred at room temp, for 2.5 h. The resulting mixture was added dropwise to a solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was purified by flash chromatography on "Cw reversed-phase silica gel" [0 = 2.5 cm, h = 12 cm, F - 20 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 90:10 -> 85:15 in 2 min, H₂O:MeCN 85:15 — » 75:25 in 15 min, H₂O:MeCN 75:25 70:30 in 3 min, H₂O:MeCN

70:30 —► 0:100 in 2 min]. The collected fractions (F12-14) and (F15-19) were freeze dried. The resulting residue of the collected fractions (F12-14) was dissolved in a minimum amount H₂O and the resulting solution was added to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted and the residue washed with acetone (2 × 10 mL). It was dissolved in H₂O and freeze dried to deliver one portion of the title compound (26) as a green solid (0.0171 g, 0.00724 mmol, 22%). The residue of the collected fractions (F15-19) was purified again by flash chromatography on "aqueous Cw reversed-phase silica gel" [0 = 2.5 cm, h = 12 cm, F = 20 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 100:0 90:10 in 2 min, H₂O:MeCN 90:10 80:20 in 10 min, H₂O:MeCN 80:20 70:30 in 5 min,

H₂O:MeCN 70:30 0:100 in 5 min]. The collected fractions (F9-10) were freeze dried. The resulting residue was dissolved in a minimum amount H₂O and the resulting solution was added dropwise to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted and the residue was washed with acetone (2 × 10 mL) and dissolved in H₂O. The aqueous solution was freeze dried to deliver a second portion of the title compound (26) as a green solid (0.0258 g, 0.0109 mmol, 33% combined yield: 55%).

Prepa ration 25: 2-[({5-[( 1 H -2, 5-Dioxopyrrol- 1 -yl)pent- 1 -yl]amino]carbonylamino) }but- 1 -yn- yl)phenoxy]-29, 31-bis[(3, 4, 5-tris{[ 1 -(sodium 3-sulfonatopropyl)-1 , 2, 3-triazol-4-yl]methoxy}- phenyl)methoxy]silanediyl-29H,31H-silicon phthalocyanine (EMBODIMENT 4 = WB692-CB2)

The silicon phthalocyanine 26 (25.0 mg, 10.58 μmol) was dissolved in dimethylsulfoxide (0.4 mL). A solution of isocyanate 22 (34.0 mg, 163 μmol, 15 equiv.) in dimethylsulfoxide (0.2 mL) was added. The resulting mixture was stirred for 9 h at room temperature. The reaction mixture was added dropwise in a saturated solution of Nal in acetone (8 mL). A precipitate formed, which was collected by centrifugation. The resulting pellet was triturated with a mixture of acetone (10 mL) and H₂O (0.8 mL) and then concentrated again by centrifugation. The supernatant liquid was decanted. The residue was purified by flash chromatography on "aqueous Cw reversed-phase silica gel" [0 = 2 cm, h = 12 cm, F = 18 mL, 20 mL/min, 10 mw HNEt₃ ^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 95:5 -> 80:20 in 4 min, H₂O:MeCN 80:20 -> 75:25 in 15 min, H₂O:MeCN 75:25 70:30 in 5 min, H₂O:MeCN

70:30 — > 0:100 in 4 min]. The collected fractions (F12-16) were freeze dried. The resulting residue was dissolved in a minimum amount H₂O. The resulting solution was added dropwise in a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was collected by centrifugation. The pellet was washed with acetone (2 × 10 mL). It was dissolved in H₂O whereupon freeze-drying delivered the title compound (EMBODIMENT 4 = WB692-CB2) as a green solid (13 mg, 5.1 μmol, 48%). 1.11 Synthesis of EMBODIMENT 5 (= silicon phthalocyanine WB795-LB1; the corresponding reactions are visualized in Figures 10 - 11)

Preparation 26: But-3-yn-1-yl 1 H-imidazole-1 -carboxylate (33)

33

Carbonyl-N.N’-diimidazol (3.216 g, 19.84 mmol, 1.50 equiv.) was dissolved in THF (100 mL). The resulting solution was cooled to 0°C. A solution of But-3-yn-1-ol (1.00 mL, 0.927 g, 13.2 mmol) in CH₂CI₂ (20 mL) was added over a period of 1 h. The reaction mixture was warmed to room temp, and was stirred for 3 h. All volatiles were removed under reduced pressure. The resulting residue was purified by silica column chromatography [0 = 4 cm, h = 17 cm, F = 50 mL, c-C₆H₁₂EtOAc — > 75:25] which delivered the title compound (33; 1.963 g, 11.96 mmol, 90%, F9-18) as a colorless solid.

Preparation 27: Naphthalene-2,3-dicarbonitrile (29)

29 alpha, alpha, alpha', a/pha'-Tetrabromo-o-xylene (20.00 g, 47.42 mmol), fumaronitrile (7.404 g, 94.84 mmol, 2.0 equiv) and Nal (15.64 g, 104.3 mmol, 2.2 equiv.) were dissolved in DMF (200 mL). The resulting mixture was stirred at 80°C for 21 h. It was cooled to room temperature and poured onto ice water and saturated aqueous NazSCh-solution (-250 mL, v:v = 1 :1). The precipitate was filtrated, washed with EtOAc (3 x 20 ml) and H₂O (100 mL). The residue was dried under vacuum over KOH for 2 d. Which delivered the title compound (29; 7.174 g, 40.26 mmol, 84%). The product crystallizes from EtOH:Aceton (v:v, 2:1 ) as slightly brown needles.

Preparation 28: 1-lmino-1H-benzo[f]isoindol-3-amine (28)

28

Naphthalodinitrile 29 (3.00 g, 16.8 mmol) was suspended in MeOH (100 mL). NaOMe (0.636 g, 11.8 mmol, 0.7 equiv.) was addded. The resulting mixture was heated under reflux and a solution of NH₃ in MeOH (7M, 20 mL) was added. The reaction mixture was stirred under reflux for 2.5 h. All volatiles were removed under reduced pressure. H₂O (100 mL) was added. The precipitate was filtrated, washed with H₂O (2 × 20 mL) and acetone (3 x 10 mL). The residue was dried under vacuum to deliver the title compound (28; 2.42 g, 12.4 mmol, 73%) as a slightly brown solid.

Preparation 29: 29,31-(Dichlorosilanediyl)-2-(4-iodophenoxy)-29H,31H-silicon

The diiminoisoindolines 5 (0.5 g, 1.38 mmol) and 28 (2.15 g, 11.0 mmol, 8.0 equiv.) were suspended in quinoline (15 mL). Under an atmosphere of N₂, SiCL (1.40 mL, 2.07 g, 12.2 mmol, 8.85 equiv.) was added dropwise. The resulting mixture was heated at 200°C for 1 h. The reaction mixture was cooled to room temp, and acetone (50 mL) was added. The resulting mixture was filtrated. The residue was washed with acetone (20 mL), MeOH (10 mL), CH₂CI₂ (20 mL) and acetone (3 x 10 mL). This delivered a black solid, which are the raw Dichloro Si-Phthalocyanines as a mixture containing A3B and A₄ (2.7031 g); it contained the expected mixture of the monosubstituted, i. e. A₃B-type silicon phthalocyanine 27 (desired) and its unsubstituted analog 29,31 -Bis{[3,4,5-tris(prop-2-yn-1 -yloxy)phenyl]methoxy}silane- diyl-29H, 31 /-/-silicon tetrabenzophthalocyanine, i. e. the A₄-type parent-silicon phthalocyanine (undesired, not depicted).

An aliquot of this crude mixture (1.2031 g), K2C03(2.00 g, 14.47 mmol) and the benzyl alcohol 9 (2.79 g, 10.3 mmol) were suspended in toluene (50 mL). The resulting mixture was heated under reflux for 8 h. It was cooled to room temperature and it was filtrated over silica with C-C₆H12 as solvent. The filter cake was rinsed off with c-C₆H-^EtOAc (v:v = 76:24) until the dark green color disappeared. All volatiles were removed under reduced pressure. The residue was purified by silica column chromatography [0 = 4 cm, h = 22 cm, F = 50 mL, c-C₆Hi2:EtOAc -> 76:24] which delivered the title compound (30; 78.5 mg, 54.2 μmol, 9% yield over 2 steps) as dark green solid.

The silicon phthalocyanine 30 (200 mg, 138 μmol), sodium 3-azidopropane-1 -sulfonate (12) (206.8 mg, 1.105 mmol, 8.0 equiv.), PPhs (23.9 mg, 91.2 μmol, 66 mol-%) and Cul (15.8 mg, 82.9 μmol, 60 mol-%) were dissolved in DMSO (2 mL). NEt₃ (0.6 mL) was added. This mixture was stirred for 8 h. The reaction mixture was added dropwise to a saturated solution of Nal in acetone (15 mL). The resulting precipitate was centrifuged, the supernatant liquid was removed. The residue was washed with acetone (2 × 10 mL). The resulting residue was purified by C₁ 8 reversed phase flash chromatography [0 = 2.0 cm, h = 15 cm, F = 20~mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN -> 80:20 in 2 min, 80:20 70:30 in 20 min, 70:30 -» 65:35 in 5 min, 65:35 -» 20:80 in 3 min]. The collected fractions (F20-25) were freeze dried. The residue was dissolved in H₂O and the resulting solution was added dropwise to a saturated Nal solution in acetone (15 mL). The resulting precipitate was centrifuged. The supernatant liquid was removed. The residue was washed with acetone (10 mL), dissolved in H₂O (10 mL) and freeze dried to deliver a first portion of the title compound (31; 0.2718 g, 0.1057 mmol, 76%) as a dark green solid. The collected fractions (F26-32) were freeze dried and the residue was purified by a second aqueous C₄ reversed phase flash chromatography [0 = 2.0-cm, h = 15 cm, F = 20 mL, 25 mL/min, 10 mM HNEt₃ ^+-OAc (which buffered at pH = 7.0), H₂O:MeCN = 100:0 90:10 in 2 min, 90:10

85:15 in 8 min, 85:15 -> 80:20 in 10 min, 80:20 — > 30:70 in 10 min]. The collected fractions (F39-45) were freeze dried. The residue was dissolved in a minimum amount of H₂O. The resulting solution was added dropwise to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated by centrifugation. The supernatant liquid was decanted and the residue washed with acetone (2 × 10 mL). It was dissolved in H₂O and freeze dried to deliver a second portion of the title compound (31; 0.0477 g, 18.6 μmol, 13% combined yield 89%).

Preparation 31 : 2-[4-({[(3-Carboxypropyl)amino]carbonyloxy}but-1-ynyl)phenoxy]-29,31- bis[(3, 4, 5-tris{[ 1 -(sodium 3-sulfonatopropyl)-1 , 2, 3-triazol-4-yl]methoxy}phenyl)methoxy]- silanediyl-29H,31H-silicon phthalocyanine (34)

The imidazolide 33 (95.80 mg, 583.6 μmol, 10 equiv.) was dissolved in degassed dimethylsulfoxide (0.5 mL). A solution of 4-aminobutyric acid (66.2 mg, 642 μmol, 11.0 equiv.) and NaOH (25.6 mg, 642 μmol, 11.0 equiv.) in degassed H₂O (0.5 mL) was added. The resulting mixture was stirred for 1 h at room temperature.

The silicon phthalocyanine 31 (0.150 g, 58.4 μmol) and (mete-NaOsS-H^eJsP (8.29 mg, 14.6 μmol, 25 mol-%) were dissolved in degassed H₂O (3 mL). Pd(OAc)2 (29 mM in MeCN, 0.1 mL, 2.9 μmol, 5 mol-%), Cul (29 mM in MeCN, 0.1 mL, 2.9 μmol, 5 mol-%), and NEts(1 mL) were added. The before mentioned reaction mixture was added dropwise during 5 h. The resulting mixture was stirred at room temp, for 24 h. The resulting mixture was added dropwise to a saturated solution of Nal in acetone (15 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The residue was washed with acetone (1 x 10 mL). The remaining pellet was purified by flash chromatography on "aqueous C₄ reversed-phase silica gel" [0 = 2.0 cm, h = 15 cm, F = 19 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), H₂O:MeCN 100:0 90:10 in 2 min, H₂O:MeCN

90:10 -> 80:20 in 8 min, H₂O:MeCN 80:20 70:30 in 15 min, H₂O:MeCN 70:30 20:80 in

10 min]. The collected fractions (F18-28) were freeze dried. The resulting residue was dissolved in a minimum amount of water and added dropwise to a saturated solution of Nal in acetone (15 mL). A precipitate formed. It was centrifuged, washed with acetone (2 × 10 mL) and dissolved in H₂O. The solution was freeze-dried to deliver the title compound (34; 0.1217 g, 0.0457 mmol, 78%) as a green solid.

The silicon phthalocyanine 34 (20.0 mg, 7.57 μmol) was dissolved in dimethylsulfoxide (0.4 mL) and pyridine (0.2 mL) was added. The resulting mixture was stirred for 10 min. Disuccinimidyl carbonate (19.4 mg, 75.7 μmol, 10 equiv.) was added. The resulting mixture was heated at 60°C for 6 h. The reaction mixture was cooled to room temp, and added dropwise to a saturated solution of Nal in acetone (8 mL). This caused the reaction product to precipitate. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was washed with acetone (2 × 10 mL). All volatiles were removed under reduced pressure to deliver the title compound (EMBODIMENT 5 = WB795- LB1) as a green solid (20 mg, 7.30 μmol, 96%). HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C₁₁₃ ¹H₁₀₂ ¹⁴N₂₈ ¹⁶O₃₃ ³²S₆ ²⁸Si]^6- (tantamount to z = 6) with m/z = 433.2552 which deviates from the calculated m/z = 433.2561 by - 2.2805 ppm.

1.12 Synthesis of EMBODIMENT 6 (= silicon phthalocyanine WB795-CB1; the corresponding reactions are visualized - or referred to - in Figure 12)

Preparation 33: 2-[4-(4-Aminobut-1-ynyl)phenoxy]-29,31-bis[(3,4,5-tris{[1-(sodium 3- sulfonatopropyl)-1 , 2, 3-triazol-4-yl]methoxy}phenyl)methoxy]silanediyl-29H,31 H -silicon tribenzophthalocyanine (35)

The silicon phthalocyanine (31; 80.0 mg, 31.1 μmol) and (meta-NaO₃S-H₄C₆)₃P (4.4 mg, 7.7 μmol, 25 mol-%) were dissolved in degassed H₂O (3 mL). Pd(OAc)2 (16 mM in MeCN, 0.10 mL, 1.7 μmol, 5 mol-%), Cul (16 mM in MeCN, 0.1 mL, 1.7 μmol, 5 mol-%) and NEt₂ (0.4 mL) were added. A solution of But-3-in-1-amin hydrochlorid (32.8 mg, 311 μmol, 10 equiv.) in degassed H₂O (1.0 mL) was added dropwise over a period of 5 h. The resulting mixture was stirred at room temp, for 2.5 h. It was added dropwise to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted. The remaining pellet was purified by flash chromatography on "C18 reversed-phase silica gel'' [0 = 2.5 cm, h = 12 cm, F = 20 mL, 25 mL/min, 10 mM HNEt3^+-OAc (which buffered at pH = 7.0), HzO:MeCN 90:10 85:15 in 2 min, H₂ O:MeCN 85:15 -+ 75:25 in 15 min, H₂ O:MeCN 75:25 -+ 70:30 in 3 min, H₂ O:MeCN 70:30 — » 0:100 in 2 min]. The collected fractions (F17-24) were freeze dried. The resulting residue was dissolved in HzO and the resulting solution was added to a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was concentrated as a pellet by centrifugation. The supernatant liquid was decanted and the residue washed with acetone (2 × 10 mL). It was dissolved in H₂O and freeze dried to deliver the title compound (35; 0.0521 g, 0.0207 mmol, 67%) as a green solid.

Preparation 34: 2-[({5-[(1H-2,5-Dioxopyrrol-1-yl)pent-1-yl]amino]carbonylamino)}but-1-yn- yl)phenoxy]-29, 31 -bis[(3, 4, 5-tris{[ 1 -(sodium 3-suifonatopropyl)-1 , 2, 3-triazol-4-yl]methoxy}~ phenyl)methoxy]silanediyl-29H,31H-silicon tribenzophthalocyanine (EMBODIMENT 6 =

WB795-CB1)

The silicon phthalocyanine 35 (25.0 mg, 9.95 μmol) was dissolved in dimethylsulfoxide (0.4 mL). A solution of isocyanate (22; 34.0 mg, 163 μmol, 15 equiv.) in dimethylsulfoxide (0.2 mL) was added. The resulting mixture was stirred for 9 h at room temperature. The reaction mixture was added dropwise in a saturated solution of Nal in acetone (8 mL). A precipitate formed, which was collected by centrifugation. The resulting pellet was triturated with a mixture of acetone (10 mL) and H₂O (0.8 mL) and then concentrated again by centrifugation. The supernatant liquid was decanted. The residue was purified by flash chromatography on "aqueous Cis reversed-phase silica gel" [0 = 2 cm, h = 12 cm, F = 18 mL, 20 mL/min, 10 mM HNEts^+-OAc (which buffered at pH = 7.0), HzO:MeCN 95:5 — > 80:20 in 4 min, HaCIMeCN 80:20 75:25 in 15 min, H₂O:MeCN 75:25 — ► 70:30 in 5 min, H₂O:MeCN

70:30 -+ 0:100 in 4 min]. The collected fractions (F20-26) were freeze dried. The resulting residue was dissolved in a minimum amount H₂O. The resulting solution was added dropwise in a saturated solution of Nal in acetone (8 mL). A precipitate formed. It was collected by centrifugation. The pellet was washed with acetone (2 × 10 mL). It was dissolved in H₂O whereupon freeze-drying delivered the title compound (EMBODIMENT 6 = WB795-CB1) as a green solid (15.1 mg, 5.55 μmol, 56%).

HRMS (neg. ion mode ESI): [M - 6 x Na®] observed as [¹²C_1i0 ¹H₁06¹⁴N₂9¹⁶O₃3³²S6²⁸Si]^6e (tantamount to z = 6) with m/z = 430.0934 which deviates from the calculated m/z = 430.0939 by -1.2088 ppm.

1.13 Cell culture

The human prostate carcinoma cell lines LNCaP, PC₃ , PC₃ -PSMA and C₄-2 as well as the bladder cancer cell line RT112 were purchased from the American Type Culture Collection (ATCC, Manassas, USA). The colon cancer cell line HCT-116 was purchased from Merk/Sigma Aldrich. The PC3-PSMA cell line was kindly provided by P. Giangrande, University of Iowa, USA. The human breast cancer cell line SK-BR3 was kindly provided by T. Erbes, University Medical Center, University of Freiburg, Germany. Cell line identity was verified by short tandem repeat (STR) analysis (CLS GmbH, Eppelheim, Germany). PC₃ - .PC₃-PSMA, LNCaP and C₄ -2 cells were routinely propagated in RPMI 1640 medium (Thermo Fischer Scientific, Waltham, USA) and SKBR-3 and RT112 cells in DMEM medium (Thermo Fischer Scientific, Waltham, USA), and HCT-116 cells in MSCB medium (Cell systems) all supplemented with 10% fetal bovine serum (Sigma-Aldrich, St. Louis, USA) and 1% penicillin/streptomycin (Sigma-Aldrich, St Louis, USA). All cells were cultured at 37°C and 5% CO₂.

1.14 Western Blot Analysis

Antigen expression was confirmed by Western Blot Analysis. In brief, target cells were lysed in RIPA buffer supplemented with 1X complete™ Protease Inhibitor Cocktail (Roche, Basel, Switzerland). Protein concentration was determined by using the QuickStart Bradford Protein Assay (Bio-Rad Laboratories, Inc., Hercules, USA). For detection of PSMA or HER2, the monoclonal mouse anti-PSMA antibody AK7 (17) or the monoclonal rabbit anti-HER2/ErbB2 antibody (Cell Signaling Technology, Danvers, USA) was used, respectively. HRP- conjugated polyclonal rabbit anti-mouse or goat anti-rabbit antibodies (DAKO by Agilent Technologies, Santa Clara, USA) were used as secondary antibodies. β-Actin was used as a loading control and was detected with help of the HRP-conjugated polyclonal rabbit anti-β-Actin antibody (Cell Signaling Technologies, Leiden, Netherlands). Western Blots were developed with an enhanced chemiluminescence (ECL) substrate (Bio-Rad Laboratories, Inc., Hercules, USA) and protein bands were detected using the ChemiDoc MP Imaging System with the Image Lab software (Bio-Rad Laboratories, Inc., Hercules, USA).

1.15 Cloning, expression and purification of the recombinant antibodies

For generation of recombinant lgG1 antibodies, the variable domains of the light (VL) and heavy chains (VH) were amplified from existing DNA vectors (provided by collaboration partners or synthesized by GeneArt, Thermo Fischer Scientific, Waltham, USA) by PCR using primers containing the corresponding restriction sites. The amplified VLs and VHs were cloned into the vectors pCSL3k and pCSEHI c, respectively, the latter containing the mutated cysteine residues.

For enzymatic digestion of the heavy and light chain vectors and inserts, the restriction endonucleases BssHII and Nhel from New England Biolabs (Ipswich, USA) and Agel and Xhol from Promega (Madison, USA) were used, respectively. Reaction buffers and incubation temperatures were chosen according to the manufacturer's instructions. For gel extraction, the QIAquick Gel Extraction Kit (Qiagen, Hilden, Germany) was used. Ligation was performed in a molar ratio of 1:3 (vector: insert) using the Rapid DNA Ligation Kit (Roche, Basel, Switzerland). The transformation of the XL1-Blue MRF' Supercompetent bacteria (Agilent Technologies, Santa Clara, USA) was performed as described in the manufacturer’s protocol. The bacteria were plated on LB agar plates (Sigma-Aldrich, St. Louis, USA) containing 0.1 mg/ml ampicillin (Sigma-Aldrich, St. Louis, USA) and single clones were transferred into liquid LB medium (Sigma-Aldrich, St. Louis, USA) containing 0.1 mg/ml ampicillin (Sigma-Aldrich, St. Louis, USA). Plasmid DNA was prepared from transformed bacteria using the NucleoSpin Plasmid Kit (Macherey-Nagel, Duren, Germany). DNA was eluted in ddHzO and concentration was determined by using the NanoDrop Lite Spectrophotometer (Thermo Fischer Scientific, Waltham, USA). Correct sequences of the plasmids were verified by sequencing (Microsynth, Balgach, Switzerland).

EXPI293F cells (Thermo Fischer Scientific, Waltham, USA) were cultured in serum-free FreeStyle F17 medium supplemented with 8 mM glutamine (PAN-Biotech, Aidenbach, Germany) and 0.1% pluronic F68 (PAN-Biotech, Aidenbach, Germany) at 37°C, 110 rpm and 5% CO2. Two days before transient transfection, EXPI293F cells were seeded at 0.5*10⁶ cells/ml, reaching ~ 1.5-2.0*10⁶ cells/ml (> 90% viability) on the day of transfection. For DNA:PEI complex formation, 1 pg DNA/ml transfection volume and 5 pg of 40 kDa PEI (Polysciences, Warrington, USA) were first diluted separately in 5% transfection volume in supplemented Free-Style F17 media. DNA (1 :1 ratio of heavy and light chain vector) and PEI was then mixed and incubated 30 min at room temperature before addition to the cells. 48 h later, the culture volume was doubled by feeding HyClone SFM4Transfx-293 media (Cytiva, Marlborough, USA) supplemented with 8 mM glutamine and 20% HyClone Boost 6 supplement (Cytiva, Marlborough, USA). One week after transfection, supernatant was harvested by centrifugation (15 min, 1500 x g) and antibodies were purified using a protein G affinity chromatography column (Cytiva, Marlborough, USA). Successful purification of the antibodies was verified by Coomassie staining (Protein Ark, Sheffield, UK) and Western Blot using a HRP conjugated polyclonal rabbit anti-human IgG antibody (DAKO by Agilent Technologies, Santa Clara, USA) for detection. Protein concentration was determined by using the Pierce BCA Protein Assay Kit (Thermo Fischer Scientific, Waltham, USA).

1.16 Conjugation of recombinant antibodies bearing engineered cysteine residues with thiol reactive dyes

For conjugation, antibodies were first adjusted with 1xPBS containing 1 mM EDTA (pH 7.4) (Serva Electrophoresis GmbH, Heidelberg, Germany) and then reduced with 40 equimolar TCEP (Carl Roth, Karlsruhe, Germany) for 3 hours at 37°C. After dialysis in 1xPBS, 1mM EDTA (pH 7.4) using the Slide-A-Lyzer Dialysis Cassettes (20K MWCO, Thermo Fischer Scientific, Waltham, USA) at 4 °C overnight, the antibodies were re-oxidized with 30 equimolar dehydroascorbic acid (Sigma-Aldrich, St. Louis, USA) for 4h at room temperature. For conjugation, the antibodies were incubated with 10 x equimolar dye at room temperature for 1 hour. To quench the reaction, 25 equimolar N-acetyl-L-cysteine (Sigma-Aldrich, St. Louis, USA) was added (15 min, room temperature), followed by dialysis against 1xPBS (pH 7.4) overnight (4°C). Unbound dye was removed by protein G affinity chromatography (Cytiva, Marlborough, USA) and dialysis against PBS. Successful conjugation and purification of the conjugates was verified by reducing or non-reducing SDS-PAGE followed by red (Amax = 680 nm) or NIR (Amax = 800 nm) fluorescence-based imaging (IVIS Spectrum, In Vivo Imaging System, PerkinElmer, Waltham, USA) or Coomassie staining (Protein Ark, Sheffield, UK). Protein concentration was determined by the Pierce BCA Protein Assay Kit (Thermo Fischer Scientific, Waltham, USA). The degree of labeling was calculated according to the TechTip#31 protocol "Calculate dye:protein (F/P) molar ratios" (Thermo Fischer Scientific, Waltham, USA).

1.17 Conjugation of recombinant antibodies with amine reactive dyes

Recombinant antibodies were incubated with 10 x equimolar dye in 0.1 M Na2HPO4 (pH 8.5) at room temperature for 2 h. Unbound dye was removed by protein G affinity chromatography purification (Cytiva, Marlborough, USA) and dialysis. Successful conjugation and purification of the conjugates was verified by reducing or non-reducing SDS-PAGE using red or NIR fluorescence-based imaging (IVIS Spectrum In Vivo Imaging System, PerkinElmer, Waltham, USA) and Coomassie staining (Protein Ark, Sheffield, UK). Protein concentration was determined by using the Pierce BCA Protein Assay Kit (Thermo Fischer Scientific, Waltham, USA). The degree of labeling was calculated according to TechTip#31 "Calculate dye:protein (F/P) molar ratios" (Thermo Fischer Scientific, Waltham, USA).

1.18 Fab fragment preparation

Fab fragments were prepared from conjugated antibodies using the Pierce Fab Preparation Kit (Thermo Fischer Scientific, Waltham, USA). Successful conjugation and purification of the conjugates was verified by reducing or non-reducing SDS-PAGE followed by red or NIR fluorescence-based imaging (IVIS Spectrum In Vivo Imaging System, PerkinElmer, Waltham, USA) or Coomassie staining (Protein Ark, Sheffield, UK). Protein concentration was determined by the Pierce BCA Protein Assay Kit (Thermo Fischer Scientific, Waltham, USA). The degree of labeling was calculated according to the TechTip#31 protocol "Calculate dye:protein (F/P) molar ratios" (Thermo Fischer Scientific, Waltham, USA).

1.19 Flow cytometry

Specific binding of the produced antibodies or conjugates was tested on cells expressing the respective surface antigen. Mean fluorescence values of stained cells were determined with a FACS Calibur Flow Cytometer and the CellQuestPro software (BD Biosciences, Heidelberg, Germany). Binding affinity of the antibodies was calculated with help of the GraphPad Prism 7 software (GraphPad Software Inc., San Diego, USA) and KD values were defined as the antibody or conjugate concentrations leading to half-maximal specific binding.

1.20 PIT

2.5*10⁵ cells were seeded per well in 35 mm cell culture dishes (Thermo Fischer Scientific) and cultivated for 24 h in the incubator (37°C, 5% CO2). On the next day, cell culture medium was removed and fresh medium containing the appropriate treatment (medium, 10 pg/ml antibody, 10 pg/ml conjugate or the equimolar amount of free dye) was administered to the cells. After incubation (37°C, 5% CO2, 24h), the cells were washed with 1x PBS and irradiated with a red light-emitting diode (LED), which emits light at A_max = 690 nm (L690-66-60, Marubeni, Tokyo, Japan) or a LED, which emits light at (A_max = 780 nm) (L780-66-60-550) at various mean irradiation doses. Power densities were quantified with an optical power meter (PM 100, Thorlabs, Newton, USA). After 24h, cell viability was analyzed using the vital dye erythrosin B (Logos Biosystems, Gyeonggi-do, South Korea) and a Neubauer Counting Chamber. Significance of the data was calculated with the Student's t test (unpaired, parametric with Welch's correlation) using the GraphPad Prism 7 software (GraphPad Software Inc., San Diego, USA).

In accordance with the above-described preparatory examples, the person skilled in the art can provide variants of the compounds according to the present invention in an analogous manner.

1,21, In vivo tumor uptake

10⁶ PC₃ -PSMA^|UC/GFP cells in 50% PBS/50% Matrigel were injected subcutaneously into the right flank of nude mice. When the tumors reached a volume of approximately 30-70 mm³ (= Day 0), the animals were injected intravenously with 100 pg h3/F11.19^T120C/D265C-WB692-CB2 or an equimolar amount of WB692-CB2 in 100 pl PBS. Fluorescence imaging (FLI) was performed 0, 1 , and 5 hours, as well as 1 , 2, 3, 4, 7, and 10 days after conjugate or dye administration using the I VIS Imaging System and the Living Image 3.0 Software. Regions of interests (ROIs) were placed over the tumor and tumor uptakes of the conjugate or dye were measured by determining the total flux (p/s) in the tumor. 1.22. In vivo PIT

For in vivo PIT, 10⁶ PC₃ -PSMA^luc/GFP cells in 50% PBS / 50% Matrigel were subcutaneously injected into the right flank of nude mice. When the tumors reached a volume of approximately 30-70 mm³ (= day 0 of treatment), the animals were intravenously injected on days 0 and 10 with 100 pg h3/F11.19^T120C/D265C-WB692-CB2 or 100 pl PBS, respectively (n=3 each). Red light irradiation of the tumors with doses of 100 J/cm²each was performed on days 3, 5, 11 and 13 using a red light emiting diode (A = 690+M Onm, 50 mW/cm²). Tumor growth was measured by palpation during treatment.

Experiment 1

PIT of prostate cancer cells with the humanized anti-PSMA antibody h3/F11var16^A118C/DZ65C linked to the dye WB692-CB1

PSMA expression was confirmed by Western Blotting in the prostate cancer cell lines LNCaP, C₄ -2, and PC₃ -PSMA, whereas PC3 cells were shown to be negative (Figure 17A).

The dye WB692-CB1 was conjugated to a humanized version of the anti-PSMA mAb 3/F11 (3/F11) containing two engineered cysteines on positions 118 (A118C) and 265 (D265C). The antibody was named h3/F11-var16^A118C/D265C. The antibody dye conjugate was named h3/F11 - var16^A118C/D285C-WB692-CB1. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 17B).

SDS gel under non-reducing conditions confirmed that the antibody was still intact after dye conjugation as an about 150 kDa molecule consisting of two heavy and two light chains. This proved that reduction of the engineered cysteines during dye conjugation does not lead to marked reduction of intrachain disulfide bonds as required for the conjugation of dyes to cysteines naturally occurring in the antibody molecule (Figure 17C).

Flow cytometry demonstrated that there was no significant difference in cell binding of the antibody dye conjugate h3/F11-var16^A118C/D265C-WB692-CB1 (KD = 0.5 pg/ml) in comparison to the free antibody h3/F11-var16^A118C/D265C (KD = 0.57 pg/ml) (Figure 17D). This confirmed that conjugation of the dye to the cysteines on positions 118 and 265 of the antibody did not impact the antigen binding. PIT using h3/F11-var16^A118C/D265C-WB692-CB1 was tested on PSMA-positive prostate cancer cells of the lines PC3-PSMA, C₄ -2 and LNCaP. The PSMA-negative cell line PC₃ was used as control. PIT using h3/F11-var16^A118C/D265C-WB692-CB1 ted to death of 96.8 % PC3-PSMA cells, 74.7% (C₄ -2) and 85.6 % (LNCaP) of PSMA-positive cells after irradiation with 32 J/cm². PSMA-negative PC3 cells remained unaffected (Figure 17E).

Surprisingly, irradiated cells incubated with equimolar concentrations of the free WB692-CB1 dye remained alive (Figure 17E). This means that the dye must be administered with help of a cell-binding molecule to be cytotoxic after red light irradiation. The free dye, on the other hand, is not cytotoxic in therapeutic concentrations, which contributes to the increased safety of our therapeutic approach.

Cells, which were treated with h3/F11-var16^A118C/D265C-WB692-CB1 , but were not irradiated, also survived. This underlines the high safety of our therapy that cells are only affected, which have bound the antibody dye conjugate and have been irradiated with red light.

Experiment 2

PIT of prostate cancer cells with the humanized anti-PSMA antibody h3/F11. ig^T1Z0C/D265C linked to the dye WB692-CB1

The dye WB692-CB1 was conjugated to another humanized version of the anti-PSMA mAb 3/F11 with two engineered cysteines on positions 120 (T120C) and 265 (D265C), called h3/F11 .19^T120C/D265C. The antibody dye conjugate was named h3/F11.19^T120C/D265C-WB692- CB1 . SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 18A). SDS gel under non-reducing conditions showed that the antibody was still intact after dye conjugation as an about 150 kDa molecule consisting of two heavy and two light chains (Figure 18B).

PIT using h3/F11.19^T120C/D265C-WB692-CB1 was tested on PSMA-positive prostate cancer cells of the line PC3-PSMA. The PSMA-negative cell line PC3 was used as control. PIT caused death of 89.9 % PC3-PSMA cells (Figure 18C), PSMA-negative PC₃ cells remained unaffected by treatment (Figure 18D). Experiment 3

PIT of prostate cancer cells with the humanized anti-PSMA Fab fragments Fab-varltf¹¹⁸⁰ linked to the dye WB692-CB1

Fab fragments were generated by digest of the antibody h3/F11-var16^A118C/D265C with papain. The Fab fragments, containing the cysteine mutation on position 118, were called Fab- var16^A118C. The dye WB692-CB1 was successfully conjugated to the Fab (Figure 19A, B) and revealed a specific killing of PSMA-positive LNCaP prostate cancer cells by PIT (Figure 19C).

Experiment 4

PIT of prostate cancer cells with the murine anti-PSMA antibody 3/F11 linked to the dye WB692-LB1

The dye WB692-LB1 was conjugated to the murine anti-PSMA mAb 3/F11 . The antibody dye conjugate was named 3/F11-WB692-LB1. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 20A). SDS gel under non-reducing conditions showed that the antibody was still intact after dye conjugation as an about 150 kDa molecule consisting of two heavy and two light chains (Figure 20B).

PIT using 3/F11-WB692-LB1 was tested on PSMA-positive PC₃ -PSMA prostate cancer cells4. The conjugate caused significant death of PC₃ -PSMA cells after irradiation, whereas cells remained alive without irradiation. Moroeover, cells that were incubated with the free dye WB692-LB1 were also not affected by treatment (Figure 20C).

Experiment 5

PIT of breast cancer cells with an anti-Her2 antibody and the dye WB692-CB1

Her-2 expression of SK-BR-3 breast cancer cells was confirmed by Western Blotting (Figure 21A). The dye WB692-CB1 was conjugated to an anti-Her2 antibody variant, derived from Trastuzumab (DBAN: DB00072) containing two cysteine mutations on positions 120 (T120C) and 265 (D265C). The antibody variant was named TRA^T12OC/D265C and the antibody dye conjugate was named TRA^T120C/D265C-WB692-CB1 . SDS gel under red light confirmed the conjugation of the dye on the heavy chain of the antibody (Figure 21 B, C). Incubation of Her- 2 expressing SK-BR-3 breast cancer cells with the conjugate followed by red light irradiation with 32 J/cm² ted to specific death of 98,9 % of the cells (Figure 21 D). Treatment of SK-BR-3 cells with TRA^T120c/D265C-WB692-CB1 and irradiation with increasing doses of red light induced increasing percentages of cell death. This proved that the cytotoxicity of the conjugate is dependent on red light irradiation dose.

Experiment 6

PIT of bladder cancer cells with an anti-EGFR antibody and the dye WB692-CB1

The dye WB692-CB1 was conjugated to an anti-EGFR antibody variant, derived from Cetuximab (DBAN: DB00002) containing two cysteine mutations on positions 120 (T120C) and 265 (D265C). The antibody variant was named Cmb^T120C®^265C and the antibody dye conjugate was named Oetuximab^T120C/D265C-WB692-CB1. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 22A). PIT using Cmb^T120C/D265C -WB692-CB1 was tested on EGFR-positive bladder cancer cells of the line RT112. The conjugate caused death of RT112 cells after irradiation with red light, whereas cells remained alive without irradiation (Figure 22B). EGFR-negative CHO cells remained unaffected by treatment (Figure 22C).

Experiment 7

PIT of prostate cancer cells with the humanized anti-PSMA antibody h3/F11.19 and the dye WB795-CB1

The dye WB795-CB1 was conjugated to the humanized version of the anti-PSMA mAb 3/F11 with two engineered cysteines on positions 120 (T120C) and 265 (D265C), called h3/F11 .19^T120C/D265C. The antibody dye conjugate was named h3/F11.19T^120C/D265C-WB795- CB1. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under NIR light (Figure 23A). PIT with h3/F11.19T^120C/D265C- WB795-CB1 specifically induced death in PC₃ -PSMA cells after irradiation with NIR light (Figure 23B) Experiment 8

PIT of prostate cancer cells with the humanized anti-PSMA antibody h3/F11. 19 and the dye WB692-CB2

The dye WB692-CB2 was conjugated to the humanized version of the anti-PSMA mAb 3/F11 with two engineered cysteines on positions 120 (T120C) and 265 (D265C), called h3/F11.19^T120C/D265C. The antibody dye conjugate was named h3/F11.19^T120C/D265C-WB692- CB2. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 24A). PIT using h3/F11.19^T120C/D265C- WB692-CB2 was tested on PSMA-positive prostate cancer cells of the line PC₃-PSMA. PIT caused death of the PC₃ -PSMA cells (Figure 24B).

Experiment 9

PIT of colon cancer cells with the chimeric anti-CD133 antibody chAC133.1 and the dye WB692-CB1

The dye WB692-CB1 was conjugated to the chimeric anti-CD133 antibody chAC₁33.1 with two engineered cysteines on positions 120 (T120C) and 265 (D265C), called chAC₁ 33.1^T120C/D265C. The antibody dye conjugate was named chAC₁ 33.1^T120C/D265C -WB692- CB1. SDS gel under reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 25A). PIT using chAC₁ 33.1^T120C/D265C - WB692-CB1was tested on CD133-positive colon cancer cells of the line HCT-116. PIT caused death the colon cancer cells depending on red light irradiation dose (Figure 25B).

^ExierimentlO

PIT of prostate cancer cells with an anti-CD44 antibody and the dye WB692-CB2

The dye WB692-CB2 was conjugated to an antibody targeting CD44 (CD44s) with two engineered cysteines on positions 120 (T120C) and 265 (D265C), called CD44^T120C/D265C. The antibody dye conjugate was named CD44^T120C/D265C-WB692-CB2. SDS gel under non-reducing and reducing conditions confirmed the conjugated dye on the heavy chain (ca. 50 kDa) of the antibody under red light (Figure 26A). PIT using CD44^T120C/D265C-WB692-CB2 was tested on CD44s-positive PC₃ -PSMA prostate cancer cells of. PIT caused specific death of the target cells (Figure 26B).

Experiment 11

Tumor uptake of the conjugate h3/F11. 19^T120C/D265C-WB692-CB2

A long-lasting fluorescence of the dye after injection of h3/F11 ,19^T120C/D265C-WB692-CB2 was detected in the subcutaneous PC₃ -PSMA tumors in nude mice over several days. This enables a long therapeutic window for subsequent single or repeated light irradiation of the tumor (Figure 27). Tumor uptake of the dye by our conjugate is thus advantageous to that by a conjugate consisting of another anti-PSMA antibody and IR700, which was tested in a comparable mouse model. With this conjugate highest tumor uptake was already measured after 24 h with a steady decrease in fluorescence over time (Nagaya et al., Mol Cancer Res. 2017 Sep; 15(9): 1153-1162).

Experiment 13

In vivo PIT with the conjugate h3/F11. 19^T120C/D265C-WB692-CB2

Mice with subcutaneous PC3-PSMA tumors were injected with h3/F11.19^T120C/D265C-WB692- CB2 or PBS as control followed by tumor irradiation with red light. Compared to the control animals, mice that were injected with the conjugate showed significantly inhibited tumor growth (*p<0.05, Figure 28).

Brief description of the Figures

Figure 1 shows representative particularly preferred embodiments of the silicon phthalocyanines B and their nomenclature.

Figure 2 shows representative particularly preferred embodiments of the silicon phthalocyanines C and their nomenclature.

Figure 3 shows the first part of the synthesis of the multiply used building blocks 13 and 14, namely the preparation of the building blocks 8 and 9. Figure 4 shows the accomplishment of the multiply used building block 13 in the course of the second part of the synthesis of the multiply used building block 14. The building block 13 precedes the fully elaborated silicon phthalocyanines EMBODIMENT 1 (= WB692-LB1), EMBODIMENT 2 (= WB692-LB2), EMBODIMENT 3 (= WB692-CB1), and EMBODIMENT 4 (= WB692-CB2B).

Figure 5 shows the accomplishment of the multiply used building block 14. It precedes the fully elaborated silicon phthalocyanine EMBODIMENT 1 (= WB692-LB1), EMBODIMENT 2 (= WB692-LB2), and EMBODIMENT 3 (= WB692-CB1).

Figure 6 shows the fourth part and thereby the end of the syntheses of the fully elaborated A₃B-type silicon phthalocyanines EMBODIMENT 1 = WB692-LB1 and EMBODIMENT 2 = WB692-LB2.

Figure 7 shows five additional silicon phthalocyanines 17, 18, 19, 20, and 21, which were synthesized in the same manner as the silicon phthalocyanine 13 (synthesis: Figure 4). Each of the silicon phthalocyanines 17, 18, 19, 20, and 21 is water-soluble.

Figure 8 shows the conversion of the silicon phthalocyanine intermediate 14 into the fully elaborated A₃B-type silicon phthalocyanine EMBODIMENT 3 = WB692-CB1.

Figure 9 shows the conversion of the silicon phthalocyanine intermediate 13 into the fully elaborated A₃B-type silicon phthalocyanine EMBODIMENT 4 = WB692-CB2.

Figure 10 shows the synthesis of the common precursor 31 of the fully elaborated A₃B-type silicon phthalocyanines EMBODIMENT 5 = WB795-LB1 and EMBODIMENT 6 = WB795-CB1.

Figure 11 shows the synthesis of the fully elaborated A₃B-type silicon phthalocyanine EMBODIMENT 5 = WB795-LB1 from the silicon phthalocyanine intermediate 31.

Figure 12 shows the synthesis of the fully elaborated A₃B-type silicon phthalocyanine EMBODIMENT 6 = WB795-CB1 from the silicon phthalocyanine intermediate 31.

Figure 13 shows the UV/VIS spectrum of the fully elaborated silicon phthalocyanine WB692- CB1 (= EMBODIMENT 3; 5 - 16 pM in H₂O; λ_max = 692 nm; pathlength = 1 cm). Figure 14 shows the UV/VIS spectrum of the precursor 31 (formula: Figure 10) of the fully elaborated silicon phthalocyanine WB795-CB1 (= EMBODIMENT 6; 4 - 15 pM in H₂O; λ_max = 795 nm, Almost max = 765 nm; pathlength - 1 cm).

Figure 15 shows the UVA/IS spectra of the silicon phthalocyanines WB692 (Abs A_max = 692 nm / Em A_max = 704 nm, Figure 13A), WB692-CB1 (= EMBODIMENT 3, Abs A_max = 693 nm / Em A_max = 703 nm, Figure 13B), and WB692-CB2 (= EMBODIMENT 4, Abs A_max = 692 nm / Em Amax = 703 nm, Figure 13C).

Figure 16 shows that the A₄-type silicon phthalocyanines 36 vs. 37 (both non-bionconjugable and studied by H. Takakura, S. Matsuhiro, M. Kobayashi, Y. Goto, M. Harada, T. Taketsugu, M. Ogawa, J. Photochem. Photobiol. 2022, 426, 113749) differ structurally from one another similarly as the A₃B-type silicon phthalocyanines Li-Cor-A from US Patent 7,005,518 differs from, e. g., compound WB692-LB1 from this invention (all bioconjugable): In 36 (judged less promising) and in Li-Cor-A the octahedrally coordinated silicon atom binds to two O-Si motifs, while in 37 (judged more promising) and, e. g., compound WB692-LB1 from this invention the octahedrally coordinated silicon atom binds to two O-C motifs.

Figure 17. (A) Western Blot of PSMA expression in prostate cancer cells, B-actin was blotted as loading control. (B) SDS PAGE of the antibody dye conjugate h3/F11-var16^A118C/D265C- WB692-CB1 under reducing conditions and (C) under non-reducing conditions after Coomassie staining and under redlight. (D) Cell binding of h3/F11-var16^A118C/D265C-WB692- CB1 to LNCaP cells in comparison to the uncoupled antibody h3/F11 ^A118C/D265C. (E) Viability of prostate cancer cells incubated with h3/F11-var16^A118C/D265C-WB692-CB1 or equimolar concentrations of free antibody or free dye 24 h after irradiation with a mean dose of 32 J/cm² red light. ****p<0.0001. The cytotoxicity of the dye on PSMA⁺ cells after irradiation is extremely strong.

Figure 18. (A) SDS PAGE of the antibody dye conjugate h3/F11 ,19^T120/D265C-WB692-CB1 under reducing conditions and (B) under non-reducing conditions after Coomassie staining and under red light. Viability of (C) PSMA-positive PC3-PSMA or (D) PSMA-negative PC3 cells incubated with h3/F11.19^T120/D265C-WB692-CB1 or equimolar concentrations of free antibody or free dye 24 h after irradiation with a mean dose of 32 J/cm² red light. ***p<0.001. A comparison of Figure 17 (C) and (D) shows the surprising activity of the construct according to the invention. Figure 19. (A) SDS PAGE of the Fab dye conjugate Fab-var16^A118C-WB692-CB1 under reducing conditions and (B) under non-reducing conditions after Coomassie staining and under

NIR light. (C) Viability of LNCaP prostate cancer cells incubated with Fab-var16^A118C -WB692- CB1 24 h after irradiation with a mean dose of 32 J/cm² red light. Controls were left untreated or incubated with Fab fragments alone or the dye alone. ***p<0.001.

Figure 20. (A) SDS PAGE of the antibody dye conjugate 3/F11-WB692-LB1 under reducing conditions and (B) under non-reducing conditions after Coomassie staining and under red light. (C) Viability of PC3-PSMA prostate cancer cells incubated with 3/F11-WB692-LB1 24 h after irradiation with a mean dose of 32 J/cm² red light. Controls were left untreated or incubated with free 3/F11 antibody or free WB-692-LB1dye.***p<0.001. Again Figure 19 (C) shows the specific activity of the construct according to the invention after irradiation.

Figure 21. (A) Western Blot of Her-2 expression in SK-BR-3 breast cancer cells, li-actin was blotted as loading control. (B) SDS PAGE of the antibody dye conjugate -[-R^^T120C/D265C_ WB692-CB1 under reducing conditions and (C) under non-reducing conditions after Coomassie staining and under red light. (D) Viability of SK-BR-3 cells incubated with TRA -WB692-CB1 or equimolar concentrations of free antibody or free dye 24 h after irradiation with a mean dose of 32 J/cm² red light. (E) Viability of SK-BR-3 cells 24 h after treatment with the conjugate TRA^T120C/D265C-WB692-CB1 and irradiation with different red light doses. * * * *p<0.0001 . Figure 20 demonstrates that the invention can be successfully performed with another tumor antigen, namely Her-2.

Figure 22. (A) SDS PAGE of the antibody dye conjugate Cetuximab^1120C/D265C-WB692-CB1 under reducing conditions after Coomassie staining and under NIR light. (B) Viability of EGFR- expressing RT112 bladder cancer cells incubated with Cetuximab -WB692-CB1 24 h after irradiation with a mean dose of 32 J/cm² red light. (C) Viability of EGFR-negative CHO cells incubated with Cextuximab^T120C/D265C-WB692-CB1 24 h after irradiation with 32 J/cm² red light. Controls were left untreated or incubated with free antibody or free WB692- CB1dye.***p<0.001.

Figure 23.(A) SDS PAGE of the antibody dye conjugate h3/F11.19^T120C/D265C-WB795-CB1 under reducing conditions after Coomassie staining and under NIR light. (B) PIT of PC₃-PSMA cells after incubation with h3/F11.19^T120C/D265C-WB795-CB1 and irradiation with different NIR light doses. PSMA-negative PC3 cells served as control *p<0.05.

Figure 24. (A) SDS PAGE of the antibody dye conjugate h3/F11.19^T120C/D265C-WB692-CB2 under reducing conditions after Coomassie staining and under red light. (B) Viability of PC₃ - PSMA prostate cancer cells incubated with h3/F11.19^T120C/D265C-WB692-CB2 24 h after irradiation with a mean irradiation dose of 32 J/cm² red light. Controls were left untreated or incubated with free antibody or free dye.

Figure 25. (A) SDS PAGE of the antibody dye conjugate chAC₁ 33.1^T120C/D265C-WB692-OB1 under reducing conditions after Coomassie staining and under red light. (B) Viability of HCT- 116 colon cancer cells incubated with chAC₁ 33.1^T120C/D265C-WB692-CB1 24 h after irradiation with increasing irradiation doses of red light.

Figure 26. (A) SDS PAGE of the antibody dye conjugate CD44^T120C/D265C-WB692-CB2 under non-reducing and reducing conditions after Coomassie staining and under red light. (B) Viability of PC3-PSMA prostate cancer cells incubated with CD44^T120C/D265C-WB692-CB2 24 h after irradiation with a mean dose of 32 J/cm² red light.

Figure 27. Tumor uptake of the conjugate h3/F11.19^T120C/D265C-WB692-CB2 in mice bearing subcutaneous PC3-PSMA tumors as measured by fluorescence imaging. The control group received the free dye WB692-CB2.

Figure 28. Tumor growth in mice bearing subcutaneous PC₃ -PSMA tumors after PIT with the conjugate h3/F11.19^T120C/D265C-WB692-CB2. The control group received the PBS as vehicle. Significant differences in tumor growth were calculated by using the Student’s t-test (unpaired, parametric with Welch's correlation (* p<0.05)).

Claims

Claims

1. Silicon phthalocyanine according to structure B or structure C or structure iso-B: or structure iso-C; of formula I, wherein:

-O-R is -O(-R¹)_p(-O)_q-R²(-R³)_s

R¹ is selected from C₁-C₃ alkyl and C(O), p is 0 or 1 , q is 0 or 1 , with the proviso that if p is 0, then q is 0,

R² is selected from alkyl, aryl, arylalkyl, (heteroaryl)alkyl, alkoxyalkyl, and heteroaryl,

R³ _is -A¹ -A²,

A¹ is selected from (heterocyclyl)alkyl-(O)_r, dihydroheteroaryl)alkyl-(O)_r, r is 0 or 1

A² is selected from di-, tri- and tetrasaccharides and -C₁-C₆ alkyl, which -C₁-C₆ alkyl is substituted with at least one group selected from sulfonic acid, phosphonic acid, carboxylic acid, and salts thereof, and s is 1 , 2 or 3,

L is a linker unit -O-L¹-L² being bound via the oxygen either to C^βof structures B and C to form an ether motif C^β-O-L¹-L² or to C^α of structures iso-B and iso-C to form an ether motif C^α-O-L¹-L² ))

L¹ is selected from aryl, arylaryl, (aryialkyl)aryl, (arylalkoxy)aryl, [(arylalkyl)amino]aryl, aroylaryl, (arylsulfanyl)aryl, and arylsulfonylaryl

L² is selected from ureido(C₁-C₆ alkyl), ureido(C₂-C₆ alkenyl), ureido(C₂-C₆ aikynyl), carbamoyloxy(C₁-C₆ alkyl), carbamoyloxy(C₂-C₆ alkenyl), carbamoyloxy(C₂-C₆ aikynyl), (alkoxycarbonyl)amino(C₁-C₆ alkyl), (alkoxycarbonyl)amino(C₂-C₆ alkenyl), (alkoxycarbonyl)amino(C₂-C₆ aikynyl), [ureido(C₁-C₆ alkyl)]amino, [carbamoyloxy(C₁-C₆ alkyl)]amino, [(alkoxycarbonyl)amino(C₁-C₆ alkyl)]amino, ureido(C₁-C₆ alkoxy), carbamoyloxy(C₁-C₆ alkoxy), (alkoxycarbonyl)amino(C₁-C₆ alkoxy), [ureido(C₁-C₆ alkyl)]thio, [carbamoyloxy(C₁-C₆ alkyl)]thio, [(alkoxycarbonyl)amino(C₁-C₆ alkyl)]thio, {[ureido(C₁-C₆ alkyl)]amino}carbonyl, {[carbamoyloxy(C₁-C₆ alkyl)]amino}carbonyl,

{[(alkoxycarbonyl)amino(C₁-C₆ alkyl)]amino}carbonyl, [ureido(C₁-C₆ alkoxy)]carbonyl, [carbamoyloxy(C₁-C₆ alkoxy)]carbonyl, [(alkoxycarbonyl)amino(C₁-C₆ alkoxy )]carbonyl, [ureido(C₁-C₆ alkyl)]carbonyl, [ureido(C₂-C₆ alkenyl)]carbonyl, [ureido(C₂-C₆ alkynyl)]carbonyl, [carbamoyloxy(C₁-C₆ alkyl)]carbonyl, [carbamoyloxy(C₂-C₆ alkenyl)]carbonyl, [carbamoyloxy(C₂-C₆ alkynyl)]carbonyl, [(alkoxycarbonyl)amino(C₁-C₆ alkyl)]carbonyl, [(alkoxycarbonyl)amino(C₂-C₆ alkenyl)]carbonyl, and [(alkoxycarbonyl)amino(C₂-C₆ alkynyl)]carbonyl

Q is -Q¹(-Q²)t-Q³

Q¹ is a linear or branched, preferably linear, C₁-C₆ alkyl group,

Q² is selected from aryl and alkylaryl, t is 0 or 1 , and

Q³ is selected from the group consisting of a) a carboxylic acid, a corresponding acyl halide, a corresponding mixed anhydride, preferably aza-analogs resulting from additions to carbodiimides or condensations with uronium salts, a corresponding activated ester, b) an electrophilic C,C double bonds, preferably α,β-unsaturated esters, α,β- unsaturated lactones (including a-alkylidene lactones), α,β-unsaturated amides, α,β-unsaturated imides (including halogenated ones), α,β-unsaturated nitriles, α,β- unsaturated ketones, α,β-unsaturated sulfones, α,β-unsaturated sulfoxides, alk-1 - enylphosphonates, nitroolefins, c) an alkyl halide, preferably a-haloketones and (haloacet)amides, an alkyl sulfonate, d) an isocyanate, isothiocyanate, e) a disulfide, a thiosulfonic acid ester, a trisulfide-S,S-dioxide, f) a phosphoramidite and g) an A/-aryl-1 , 2, 4-triazolin-3, 5-dione.

2. Silicon phthalocyanine according to claim 1, wherein the linker L has a structure selected from the group consisting of any one of

(either Het = NH and Het' = NH or Het = O and Het' = NH or Het = NH and Het' = O)

3. Silicon phthalocyanine according to any of claims 1 or 2, characterized in that Q has a structure selected from the group consisting of any one of

4. Silicon phthalocyanine according to any of claims 1 to 3, wherein the residue R of the

OR groups has a structure as shown in

5. Silicon phthalocyanine according to any of claims 1 to 4 characterized in that Q³ is a reactive or an activable functional group which is configured to form a covalent bond to a molecule capable of target-directed binding, wherein said molecule is selected from the group consisting of, but not limited to, antibodies, antibody fragments, nanoparticles nanobodies, antigens, ligands, receptors, enzymes, proteins, peptides, small molecules, hormones, inhibitors, aptamers, cells, phages, viruses, DNA, RNA, lipids, carbohydrates, polysaccharides, nanomaterials or chemical drugs.

6 Silicon phthalocyanine according to any of claims 1 to 5, wherein the residue Q³ is covalently bound to a molecule capable of target-directed binding, wherein said molecule is selected from the group consisting of, but not limited to, antibodies, antibody fragments, nanoparticles, nanobodies, antigens, ligands, receptors, enzymes, proteins, peptides, small molecules, hormones, inhibitors, aptamers, cells, phages, viruses, DNA, RNA, lipids, carbohydrates, polysaccharides, nanomaterials or chemical drugs.

7. Silicon phthalocyanine according to claim 5 or 6, wherein said molecule binds to a target structure which is associated with a disease.

8. Silicon phthalocyanine according to any of claims 5 to 7, characterized in that the target structure is selected from the group of, but not limited to tumor associated antigens.

9. Silicon phthalocyanine according to any of claims 1 to 8 for use in therapy of tumor associated diseases.

10. Silicon phthalocyanine according to any of claims 1 to 8 for use in theranostics whereby the dye is activated by a light source in the red / near infrared wavelength for diagnosis and therapy.

11. Silicon phthalocyanine according to any of claims 1 to 8 for use in ex vivo diagnosis.

12. Silicon phthalocyanine according to any of claims 1 to 8 for use in a dual-labeled molecule, where the first label is the silicon phthalocyanine and the second label is a radioactive tracer for pre-, intra- and post-operative diagnosis and therapy

13. Silicon phthalocyanine according to any of claims 1 to 8 for use in combination with drugs that further enhance tumor-cell-selective systemic host-immunity

14. Use of a compound of formula HO-L¹-Hal in the preparation of a silicon phthalocyanine, wherein L¹ is defined as in claim 1 and Hal is a halogen selected from I, Br, and CL

15. Use according to claim 14, wherein the silicon phthalocyanine is according to any of claims 1 to 8 and the compound of formula HO-L¹-Hal is selected from

16. Silicon phthalocyanine according to any of claims 1 to 8 for use in medicine for the selective removal of benign cells.

17. Silicon phthalocyanine for use according to claim 16, wherein the benign cells are hyperplastic tissues or cells targeted for removal in aesthetic medicine.

18. A pharmaceutical formulation comprising a silicon phthalocyanine according to any one of claims 1 to 8.

19. A pharmaceutical formulation according to claim 18, wherein the formulation is a gel, a cream, a solution, or injectable.