EP2534207A1

EP2534207A1 - Stöber method for preparing silica particles containing a phthalocyanine derivative, said particles and the uses thereof

Info

Publication number: EP2534207A1
Application number: EP11704587A
Authority: EP
Inventors: Aurélien AUGER
Original assignee: Commissariat a lEnergie Atomique CEA; Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Current assignee: Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Priority date: 2010-02-11
Filing date: 2011-02-10
Publication date: 2012-12-19
Also published as: US20120308826A1; WO2011098504A1; FR2956109B1; FR2956109A1

Abstract

The present invention relates to a method for preparing a silica particle incorporating at least one phthalocyanine derivative, said particle being prepared from at least one silicon phthalocyanine derivative via hydrolysis of said derivative in an alcohol solution. The present invention also relates to the silica particles thus prepared and to the uses thereof.

Description

PROCESS FOR THE STOBER PREPARATION OF SILICA PARTICLES CONTAINING A PHTHALOCYANINE DERIVATIVE

PARTICLES AND THEIR USES

DESCRIPTION

TECHNICAL AREA

The present invention relates to the field of silica particles and in particular silica nanoparticles containing silica phthalocyanine dyes.

Indeed, the present invention relates to a process for preparing silica particles incorporating phthalocyanine and naphthalocyanine derivatives. It also relates to silica particles incorporating phthalocyanine and naphthalocyanine derivatives, capable of being prepared by this process and their various uses and applications.

STATE OF THE PRIOR ART

The synthesis and properties of dyes derived from complexes of phthalocyanines or silicone naphthalocyanines having axial ligands have been described in the literature by Kenney

[1], Joyner [2], and Esposito [3]. Considerable interest has developed in recent years for the physical and chemical properties of phthalocyanines. This interest comes partly from their possible applications in various fields such as electrophotography [4], liquid crystals [5], conducting polymers [6], electrochromic display [7], photoelectrochemical energy conversion [8], infrared absorbing agents for transparent thermoplastics and crosslinked polymers [9] and photoconductivity [10].

Indeed, phthalocyanines and other macrocyclic analogues have attracted considerable attention as molecular materials with exceptional electronic and optical properties. These properties come from the delocalization of the electronic cloud, and make these products interesting for different areas of research in materials science and especially in nanotechnology. Thus, phthalocyanines have been successfully incorporated into semi ^¬ conductor components, electrochromic devices, information storage systems.

A crucial problem to consider in incorporating phthalocyanines into technological devices is the control of the spatial arrangement of these macrocycles. This makes it possible to extend and improve the chemical and physical properties of phthalocyanines at the macromolecular or molecular scale. The co-facial superposition of the phthalocyanines is necessary in order to obtain supramolecular properties. For example, the increase in conductivity can be along the main axis of the phthalocyanine stacking system by delocalization of electrons through the co-planar macrocycles. Conductivity in phthalocyanine-based systems generally depends on the intrinsic properties of particular phthalocyanines. Thus, silicone phthalocyanines have been used for the preparation of devices such as field effect transistors. Good conductivity is also obtained in phthalocyanine-based polymers. Among a wide variety of semi ^¬ conductor polymers based on phthalocyanines, the most important family is that of siloxane phthalocyanine [PcSiC ^ ln -

Thus, nano-objects and other siloxane phthalocyanine polymers are well known in the art. These structures are made in various ways in the literature. Several methods have been validated for the polymerization of silica phthalocyanine.

The preparation of phthalocyanine polysiloxanes has been described in the literature. Thus polymers were synthesized using silicone phthalocyanines as precursors. These compounds are used in the Langmuir-Blodgett film preparation, one-dimensional films of very rigid polymer type [11]. The polymerization is carried out under vacuum at 350-400 ° C for 2 h, very extreme conditions. Another polymer synthesis is conducted with the same silicone phthalocyanine precursor in dimethylsulfoxide at 135 ° C for 24 h [12]. More recently, a new and more timely protocol has been reported to prepare oligomers of 3 to 4 monomer units (silicone phthalocyanine) [13], said protocol comprising condensation of the monomers in the presence of quinoline followed by silylation with tert-butyldimethylsilyl chloride (TBDMSC1).

Another approach has been developed to obtain a polymer crosslinked axially in terms of the aromatic macrocycle of phthalocyanine. Thus, axial functionalization has led to the production of silicone phthalocyanine conjugated axially with a poly (polyshepic acid anhydride). The product thus obtained was then used to form hydrophilic nanoparticles via a microphase inversion method [14].

It should be emphasized that, in general, these polymers produce high electrical conductivities. However, these materials are both insoluble in water and in common organic solvents, which makes their industrial preparation difficult. Indeed, the organic nature of phthalocyanine aromatic macrocycles makes them very insoluble. Insolubility is more evident when using naphthalocyanines or anthracene analogues. This phenomenon is partly due to the aggregates formed by π-π interactions. Thus, it is sometimes necessary to substitute the aromatic macrocycle in peripheral and / or non-peripheral positions in order to confer on this family of dyes a good solubility in organic solvents. Unfortunately, this functionalization can lead to changes in intrinsic properties. So in some cases it is better to keep the aromatic network of the unsubstituted macrocycle.

The encapsulation of silicone phthalocyanines has also been the subject of some studies. In view of the pronounced and recognized hydrophobicity of phthalocyanine-based materials, it is thus very difficult to encapsulate them in silica nano-objects using a conventional wet process.

Thus, a derivative of silicone phthalocyanine bis-oleate has been introduced into lipoprotein nanoparticles, in order to use these products as lipoprotein-based nanoplateforms. These compounds are subsequently used as multifunctional and therapeutic diagnostic devices [15]. A patent application also relates to the encapsulation of copper phthalocyanine crystals (no silicone presence mentioned)

[16]. The study of the nanoparticles thus prepared for the inks containing dispersions, for the color filters and the photosensitive and colored resin composition is also reported [17].

Another study describes the formation of cadmium selenide nanoparticles (CdSe) conjugated to silicone phthalocyanines. The surface of the CdSe nanoparticles is thus functionalized by condensation of the active group (amino group) located in the axial position of the macrocycle of the silicone phthalocyanine and connected thereto via an alkyl group [18]. A similar study published in 2006 presents the introduction of tetrasulphonate Copper phthalocyanine on the surface of silica nanoparticles modified by functionalization with amino groups [19].

International application WO 2008/138727 reports the preparation of silica nanoparticles functionalized with copper phthalocyanine. The siloxane function carried by the copper phthalocyanine and necessary for the formation of silica nanoparticles, is in the peripheral position and requires a step of functionalization of the copper phthalocyanine

[20].

Finally, in 2006, phthalocyanine nanoparticles were designed and synthesized for the distribution of hydrophobic photosensors developed for photodynamic therapy against cancer. Phthalocyanine-stabilizing gold nanoparticles have an average diameter of 2 to 4 nm. Phthalocyanines are present on the surface of gold nanoparticles, and are functionalized with thiolated groups (-SH). Thus, the thiol function provides the necessary reactivity for the covalent assembly of the photosensor on the surface of the gold nanoparticles [21].

The methods of the state of the art for preparing phthalocyanine-based materials require, for the most part, several steps and / or the prior functionalization of the phthalocyanines, which makes them difficult to use industrially.

Thus, there is a real need for a simple, practical and industrial process for preparing phthalocyanine-based materials such as silica particles.

STATEMENT OF THE INVENTION

The present invention overcomes the disadvantages and technical problems listed above. Indeed, the latter proposes a process for the preparation of spherical silica-based particulate materials and in particular nanoparticulate materials incorporating phthalocyanine derivatives, said process being applicable at the industrial level, not requiring processes or heavy steps (e.g. and using easily accessible, non-hazardous and low-toxicity products.

The work of the inventors has demonstrated that the use of silicone phthalocyanine derivatives as precursors of silica makes it possible to manufacture silica particles such as silica nanoparticles incorporating phthalocyanine derivatives. The availability of axial ligands such as hydroxyls or chlorides, combined with the presence of the silica atom introduced into the cavity of the phthalocyanine macrocycle, makes it possible to use it as a precursor necessary for the proper synthesis of silica nanoparticles by the Stober route. classic.

Indeed, phthalocyanine has a central cavity allowing the incorporation of a large number of atoms, including silicon. The silicon atom being tetravalent and requiring two bonds for its incorporation into the cavity and the plane of the aromatic macrocycle of phthalocyanine, two bonds remain available. These two bonds are axial to the plane defined by the silicon atom and phthalocyanine, and are generally terminated by hydroxyl or chloride type functions. These functions being reactive, they participate as reagents in the sol-gel synthesis of silica nanoparticles.

Stober synthesis implemented in the context of the present invention is more suitable for the preparation of large amounts of silica, also more conducive to the preparation of industrial quantities of materials for marketing a product. The amount of material is preferred to control the size of the nano-objects thus prepared.

In addition, in the context of the present invention, the surface of the silica particles obtained by the process according to the invention can be functionalized thus making it possible to influence the polarity of the particles, and thus the affinity with the solvent to be used in the process. case of the application, that is to say, polar, apolar, etc. and therefore the desired dispersion. Thus, the present invention relates to a process for preparing a silica particle incorporating at least one phthalocyanine derivative, said particle being prepared from at least one silicone phthalocyanine derivative by hydrolysis of said silicone phthalocyanine derivative in an alcoholic solution. . The process used to prepare the silica particles in the context of the present invention uses the conventional Stöber method described in the article by Stöber et al., 1968 [22]. This technique involves hydrolyzing a silane derivative in an alcohol.

In the context of the present invention, the terms "silicone phthalocyanine derivative" and "phthalocyanine silane derivative" are equivalent and can be used interchangeably.

By "silicone phthalocyanine derivative" is meant a compound of formula (I):

(I)

in which :

R 1, R ₂ , 3 and R ₄ , which are identical or different, represent an optionally substituted arylene group and

R5 and R6, which are identical or different, are chosen from the group consisting of -Cl, -F, -OH and -OR 'with R' representing a linear or branched alkyl of 1 to 12 carbon atoms and in particular from 1 to 6 carbon atoms, optionally substituted. By "optionally substituted" is meant, in the context of alkyl groups, compounds of formula (I), substituted by a halogen, an amino group, a diamine group, an amide group, an acyl group, a vinyl group, a group hydroxyl, an epoxy group, a phosphonate group, a sulfonic acid group, an isocyanate group, a carboxyl group, a thiol (or mercapto) group, a glycidoxy group or an acryloxy group and in particular a methacryloxy group. Advantageously, R 'represents a methyl or an ethyl.

In the context of the present invention, the term "arylene group" means an aromatic or heteroaromatic carbonaceous structure, optionally mono- or polysubstituted, consisting of one (or more) aromatic or heteroaromatic ring (s) comprising each of 3 to 8 atoms, the (or) heteroatom (s) may be N, 0, P or S.

By "optionally substituted" is meant an arylene group which may be mono- or polysubstituted by a group selected from the group consisting of a carboxylate; an aldehyde; an ester; an ether; a hydroxyl; a halogen; aryl such as phenyl, benzyl or naphthyl; alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted such as methyl, ethyl, propyl or hydroxypropyl; an amine; a friend of ; a sulfonyl; a sulphoxide and a thiol.

Advantageously, the groups R 1, R ₂ , R 3 and R 4 are identical or different, each representing a phenylene, a naphthylene or a anthracene. More particularly, the groups R 1, R ₂ , R 3 and R 4 are identical and represent a phenylene, a naphthylene or an anthracene. In particular, the silicone phthalocyanine derivative used in the context of the present invention is a compound of formula (II):

in which :

the groups R7 to R22, which are identical or different, are chosen from the group consisting of hydrogen; a carboxylate; an aldehyde; a ketone; an ester; an ether; a hydroxyl; a halogen; aryl such as phenyl, benzyl or naphthyl; an alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted such as a methyl, a ethyl, propyl or hydroxypropyl; an amine; a friend of ; a sulfonyl; a sulphoxide and a thiol.

the groups R ₅ and R 6 are as previously defined.

A compound of formula (II) which is preferred in the context of the present invention is the compound in which the groups R 7 to R ₂₂ represent a hydrogen and the groups R ₅ and R 6 are as previously defined.

As a variant, the silicone phthalocyanine derivative used in the context of the present invention is a compound of formula (III) of the naphthalocyanine type:

(III)

in which : the groups R ₂₃ to R 46, which are identical or different, are chosen from the group consisting of hydrogen; a carboxylate; an aldehyde; a ketone; an ester; an ether; a hydroxyl; a halogen; aryl such as phenyl, benzyl or naphthyl; alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted such as methyl, ethyl, propyl or hydroxypropyl; an amine; a friend of ; a sulfonyl; a sulphoxide and a thiol.

the groups R ₅ and R 6 are as previously defined.

A compound of formula (III) that is preferred in the context of the present invention is the compound in which the groups R ₂ to R 46 represent a hydrogen and the groups R ₅ and R 6 are as previously defined.

In the formulas (I), (II) and (III), the dotted bonds represent coordination bonds or dative bonds.

Advantageously, the groups R 5 and R 6 in the compounds of formula (I), (II) or (III) are identical and are chosen from the group consisting of -Cl, -F, -OH and -OR 'with R' representing a alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted and in particular selected from the group consisting of -Cl, -F, -OH, -OCH ₃ and -OC ₂ H ₅ . More particularly, the groups R 5 and R 6 in the compounds of formula (I), (II) or (III) are identical and represent -OH or -Cl. The compounds of formula (II) and (III) most particularly used in the context of the present invention are a phthalocyanine dodichlorosilane complex, a phthalocyanine dihydroxysilane complex, a naphthalocyaninodichlorosilane complex and a naphthalocyaninatodihydroxysilane complex. These complexes can be represented with R representing -OH or -Cl as follows:

The process according to the invention comprises, more particularly, the following successive steps:

a) preparing a first solution (S _a ) containing at least one silicone derivative of phthalocyanine and optionally at least one silane compound, b) adding, to the solution (S _a ) obtained in step (a), a second solution (S ') comprising at least one compound allowing the hydrolysis of silane compounds and at least one alcohol,

c) adding to the solution (S _b ) obtained in step (b) a solvent for destabilizing said solution,

d) recovering the silica particles incorporating at least one silicone phthalocyanine derivative, precipitated during step (c).

Step (a) of the process according to the invention therefore consists in preparing a solution (S _a ) containing at least one silicone phthalocyanine derivative, in particular as previously defined. Any technique making it possible to prepare such a solution can be used in the context of the present invention.

Advantageously, the solution (S _a ) is obtained, during step (a) of the process according to the invention, by mixing together:

at least one silicone derivative of phthalocyanine,

at least one polar solvent and

optionally at least one silane compound.

Advantageously, the phthalocyanine silicone derivative, the polar solvent and the optional silane-based compound are added one after the other and, in the following order, silicone phthalocyanine derivative and then polar solvent and then the optional compound based on silane. By "polar solvent" is meant in the context of the present invention a solvent selected from the group consisting of water, deionized water, distilled water, acidified or basic, hydroxylated solvents such as methanol, the ethanol and isopropanol, low molecular weight liquid glycols such as ethylene glycol, dimethyl sulfoxide (DMSO), acetonitrile, acetone, tetrahydrofuran (THF) and mixtures thereof. Advantageously, the solution (S _a ) is an alcoholic solution and the polar solvent of the solution (S _a ) is a hydroxylated solvent such as methanol, ethanol and isopropanol. More particularly, the polar solvent of the solution (S _a ) is ethanol. More particularly, the solution (Sa) is an alcoholic solution which comprises, in addition to the hydroxylated solvent as defined above, a THF cosolvent for solubilizing the silicone phthalocyanine derivative. The silicone derivative (s) of phthalocyanine may be used during step (a) of the process according to the invention, in solid form, in liquid form or in solution in a polar solvent. When several different silicone phthalocyanine derivatives are used, they may be mixed at one time or added one after the other or in groups.

When the silicone derivative (s) phthalocyanine (s) is (are) used in solution in a polar solvent, the latter may be identical to or different from the polar solvent of the solution (S _a ). Advantageously, the polar solvent used to dissolve the phthalocyanine silicone derivative (s) is different from the polar solvent of the solution (S _a ). The polar solvent used to dissolve the derivative (s) ) silicone (s) phthalocyanine is, in particular, THF.

The mixture during step (a) is carried out with stirring using a stirrer, a magnetic bar, an ultrasonic bath or a homogenizer, and may be used at a temperature of between 10 and 40 ° C., advantageously between 15 and 30 ° C and, more particularly, at room temperature (ie 23 ° C ± 5 ° C).

In the solution (S _a ), the silicone phthalocyanine derivative or the silicone phthalocyanine derivative mixture has a molarity of between 50 μΜ and 100 mM, in particular between 100 μΜ and 50 mM and in particular between 1 mM and 10 mM. . The polar solvent or the mixture of polar solvents (polar solvent in which the phthalocyanine silicone derivative (s) is (are) in solution and / or other polar solvent of the solution (S _a )) is present, in the solution (S _a ), in a proportion of between 60 and 100%, especially between 70 and 90% and, in particular, between 75 and 85% by volume relative to the total volume of said solution.

The presence in the solution (S _a ) of a silane-based compound or of several silane-based compounds is optional. When a silane-based compound or more than one silane compound, which is the same or different, is (are) present, it (s) is (are) incorporated in the solution (S _a ) to give, just like the silicone derivative (s) phthalocyanine, by sol-gel reaction, the silica of the silica particles according to the 'invention.

The silane-based compound (s) can be introduced into the solution (S _a ) in solid form, in liquid form or in solution in a polar solvent. When several different silane compounds are used, they may be mixed at one time or added one after the other or in groups.

When the silane compound (s) is (are) used in solution in a polar solvent, the latter may be identical to or different from the polar solvent of the solution (S _a ). It may also be identical to or different from the polar solvent used to dissolve the phthalocyanine silicone derivative (s).

Advantageously, the compound (s) based on silane is (are) introduced into the solution (S _a ) in liquid form. In the solution (S _a ), the silane-based compound (s) is (are) present in a proportion of between 0.1 and 40%, in particular between 1 and 30%, and in particular, between 5 and 25% by volume relative to the total volume of said solution.

In the solution (S _a ), the silane-based compound (s) has (are) a molarity of between 50 μΜ and 100 mM, in particular between 100 μΜ and 50 mM and, in particular, between 1 mM. and 10 mM. Advantageously, said silane-based compound (s) is (are) of general formula SiR _a R _b R _c Rd in which R _a , R _b , R _c and R _d are, independently of one another, selected from the group consisting of hydrogen; a halogen; an amino group; a diamine group; an amide group; an acyl group; a vinyl group; a hydroxyl group; an epoxy group; a phosphonate group; a sulfonic acid group; an isocyanate group; a carboxyl group; a thiol group (or mercapto); a glycidoxy group; an acryloxy group such as a methacryloxy group; an alkyl group, linear or branched, optionally substituted, of 1 to 12 carbon atoms, especially 1 to 6 carbon atoms; an aryl group, linear or branched, optionally substituted, of 4 to 15 carbon atoms, in particular of 4 to 10 carbon atoms; an alkoxyl group of formula -OR _e with R _e representing an alkyl group as defined above and their salts.

By "optionally substituted" is meant, in the context of alkyl and aryl groups, silane compounds substituted with halogen, amino group, diamine group, amide group, acyl group, vinyl group, hydroxyl group, an epoxy group, a phosphonate group, a sulfonic acid group, an isocyanate group, a carboxyl group, a thiol group (or mercapto) a glycidoxy group or an acryloxy group and in particular a methacryloxy group.

In particular, said silane-based compound (s) is (are) alkyl (or) alkylsilane (s) and / or (or) alkoxysilane (s). Also, the silane compound is more particularly selected from the group consisting of dimethylsilane (DMSi), phenyltriethoxysilane (PTES), tetraethoxysilane (TEOS), tetramethoxysilane (TEMOS), n-octyltriethoxysilane, octadecyltriethoxysilane, dimethyldimethoxysilane (DMDMOS), (3-mercaptopropyl) trimethoxysilane, (3-mercaptopropyl) triethoxysilane, (mercapto) triethoxysilane, (3-aminopropyl) triethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane, 3- [bis (2-hydroxyethyl) amino] propyltriethoxysilane,

Hexadecyltrimethoxysilane, phenyltrimethoxysilane, N- [3- (trimethoxysilyl) propyl] -1,2-ethanediamine and acetoxyethyltriethoxysilane, 2-hydroxy-4- (3-triethoxysilylpropoxy) diphenyl ketone, methyltriethoxysilane, vinyltrimethoxysilane; (3-glycidoxypropyl) trimethoxysilane, (benzoyloxypropyl) trimethoxysilane, sodium 3-trihydroxysilylpropylmethylphosphonate, (3-trihydroxysilyl) -1-propanesulphonic acid, (diethylphosphonatoethyl) triethoxysilane, and mixtures thereof. More particularly, the silane compound is tetraethoxysilane (TEOS, Si (OC ₂ H ₅ ) ₄ ).

In order to functionalize the surface of the silica particles obtained according to the invention, the silane compound used may be a mixture containing less than 20% and in particular 5 to 15% of a prefunctionalized silane relative to to the total amount of silane compounds. For example, a mixture containing TEOS and from 5 to 15% of mercaptotriethoxysilane can be used for the preparation of silica particles according to the invention and functionalized with thiol groups.

Stage (b) of the process according to the invention aims to provide for the hydrolysis of a silane-based compound in an alcoholic solution by adding to the solution (S _a ) a compound allowing this hydrolysis and an alcohol in the form of an alcoholic polar solvent.

Step (b) consists, more particularly, in adding to the solution (S _a ), a solution (S ') obtained by mixing together:

optionally at least one non-alcoholic polar solvent,

at least one polar solvent alcoholic and

at least one compound for hydrolyzing the silane compound.

Advantageously, the (or any) non-alcoholic polar solvent (s), the alcoholic polar solvent (s) and the compound (s) (s) ( s) allowing the hydrolysis of the silane compound are added one after the other and, in the following order:

eventual non-alcoholic polar solvent (s) and then

polar solvent (s) alcoholic (s) then

- any non-alcoholic polar solvent (s), identical to or different from (or any possible non-alcoholic polar solvent (s) previously added and then

compound (s) for hydrolyzing the silane compound.

The solution (S ') can be prepared before, after or simultaneously with step (a) of the process according to the present invention. Advantageously, the solution (S ') is prepared before step (a) of the process according to the present invention.

The optional non-alcoholic polar solvent (s) is (are) chosen from the group consisting of water, deionized water and distilled water, acidified. or basic, low molecular weight liquid glycols such as ethylene glycol, dimethyl sulfoxide (DMSO), acetonitrile, acetone, tetrahydrofuran (THF) and mixtures thereof.

Advantageously, the nonalcoholic polar solvents present in the solution (S ') are especially deionized water and THF. More particularly, during the preparation of the solution (S '), the alcoholic polar solvent is mixed with the water, in particular deionized water, before adding the THF.

The (or any) non-alcoholic polar solvent (s) is (are) present in the solution (S ') in a proportion of between 30 and 80%, especially between 40 and 70% and, in particular, between 50 and 60% by volume relative to the total volume of the solution (S '). The alcoholic polar solvent (s) corresponds to the solvent (s) hydroxylated (s) such as methanol, ethanol and isopropanol. More particularly, the alcoholic polar solvent of the solution (S ') is ethanol.

The (or any) alcoholic polar solvent (s) is (are) present in the solution (S ') in a proportion of between 10 and 95%, especially between 20 and 70% and, in particular, between 30 and 50% by volume relative to the total volume of the solution (S ').

It should be noted that the term "compound allowing the hydrolysis of silane-based compounds" means a compound which allows not only the hydrolysis of a silane-based compound but also the hydrolysis of a silicone phthalocyanine derivative. .

The compound for hydrolyzing the silane compound is advantageously selected from the group consisting of ammonia, sodium hydroxide (KOH), lithium hydroxide (LiOH), sodium hydroxide (NaOH) , triethylamine and pyridine and, advantageously, a solution of such a compound in a polar solvent, which is identical or different, to the polar solvent (s) used during step (a). The compound for hydrolyzing the silane-based compound is, more particularly, ammonia or a solution of ammonia in a polar solvent as defined above. Indeed, ammonia acts as reagent (¾0) and as a catalyst (NH ₄ OH) of the hydrolysis of the silane-based compound or silicone phthalocyanine derivative. The compound allowing the hydrolysis of the silane-based compound, when it is in solution in a polar solvent, is present in a proportion of between 5 and 50%, in particular between 10 and 40% and, in particular, between 20 and 50%. 30% by volume relative to the total volume of said solution.

In addition, said solution is present in a proportion of between 0.05 and 20%, especially between 0.1 and 10% and, in particular, between 0.5 and 5% by volume relative to the total volume of the solution ( S ').

Step (b) of the process according to the present invention therefore consists in adding the solution (S ') to the solution (S _a ) prepared during step (a). This addition is slow and, in particular, drip.

The ratio [volume of solution (S _a )] / [volume of solution (S ')] is advantageously between 1/1 and 1/20, in particular between 1/2 and 1/10 and, in particular, between 1 / 4 and 1/8.

Step (b) can be carried out with stirring using a stirrer, a magnetic bar, an ultrasonic bath or a homogenizer. Advantageously, this agitation is implemented once the addition of the solution (S ') is complete. Step (b) may be carried out at a temperature of between 10 and 40 ° C., advantageously between 15 and 30 ° C. and, more particularly, at room temperature (ie 23 ° C. ± 5 ° C.) for a period of time. between 6 and 48 hours, particularly between 12 and 36 hours and, in particular, during When the silane compound used is TEOS, the reaction that occurs during step (b) of the process ie the condensation of the phthalocyanine silicone derivative with TEOS in the presence of ammonia can be schematized as follows:

Step (c) of the process according to the invention aims at precipitating the silica particles by adding a solvent which does not denature the structure of the particles but which destabilizes or denatures the solution (Sb) obtained in step (b). ).

Advantageously, the solvent used is a polar solvent as defined above. A particular polar solvent to be used in step (c) is selected from the group consisting of ethanol, acetone and methanol. Advantageously, the solvent used in step (c) of the process according to the invention is ethanol. Thus, is added to the solution (S _b ), a volume of solvent greater than the volume said solution, in particular greater by a factor of 1.5; in particular, greater by a factor of 2; and even greater by a factor 3. Any technique making it possible to recover the silica particles incorporating at least one phthalocyanine derivative precipitated during step (c) may be implemented during step (d) of the process according to the invention. Advantageously, this step (d) implements one or more steps, identical or different, chosen from the centrifugation, sedimentation and washing steps.

The washing step (s) is (are) carried out in a polar solvent as defined above. When the recovery step uses several washes, the same polar solvent is used for several or even all washes or several different polar solvents are used at each wash.

Regarding one (or more) centrifugation stage (s), it (they) can be implemented by centrifuging the silica particles, in particular in a wash solvent at room temperature, at a speed between 4000 and 8000 rpm and, in particular, of the order of 6000 rpm (ie 6000 ± 500 rpm) and this, for a period of between 5 min and 2 h, in particular between 10 min and 1 h and, in particular, during 15 min.

Advantageously, step (d) of the process according to the present invention consists of 4 successive washes, each followed by sedimentation by centrifugation. More particularly, the first 3 washes are carried out with a hydroxylated solvent and in particular with ethanol and the last with water.

The method according to the present invention may comprise, following step (d), an additional step of purifying the silica particles obtained hereinafter referred to as "step (e)".

Advantageously, this step (e) consists in putting the recovered silica particles after step (d) of the process according to the invention in contact with a very large volume of water. By "very large volume" is meant a volume greater by a factor of 50, in particular by a factor of 500 and, in particular, by a factor of 1000 to the volume of silica particles, recovered after step (d) of process according to the invention. Step (e) may be a dialysis step, the silica particles being separated from the volume by a cellulose membrane, of the Zellu trans type (Roth company). Alternatively, an ultrafiltration step may be provided instead of the dialysis step, via a polyethersulfone membrane.

Step (e) may, in addition, be carried out with stirring using a stirrer, a magnetic bar, an ultrasonic bath or a homogenizer, at a temperature of between 0 and 30 ° C., advantageously between 2 and 20 ° C. ° C and, more particularly, cold (ie 6 ° C ± 2 ° C) and this, for a period of between 30 h and 15 d, especially between 3 and 10 days and in particular for 1 week.

The present invention also relates to the solution (S _b ) that can be implemented in the context of the process according to the invention. This solution includes:

one (or more) polar solvent (s) alcoholic (s), including such (s) as previously defined (s),

one (or more) non-alcoholic polar solvent (s), in particular such as previously defined (s),

one (or more) phthalocyanine silicone derivative (s), especially such as previously defined and typically of formula (I) as previously defined,

optionally one (or more) silane compound (s), especially such as previously defined (s), and

one (or more) compound (s) capable (s) of hydrolyzing a compound based on silane, especially such as previously defined (s). Advantageously, the solution (S _b ) which is the subject of the present invention comprises:

one or more alcoholic polar solvent (s) in an amount of between 20 and 80% and in particular between 30 and 70%, at least one non-alcoholic polar solvent in an amount of between 15 and 75% and in particular between 20 and 65%,

one (or more) phthalocyanine silicone derivative (s) in an amount of between 10 μΜ and 20 mM, in particular between 20 μΜ and 10 mM and in particular between 200 μΜ and 2 mM,

optionally at least one silane compound in an amount of between 10 μΜ and 20 mM, in particular between 20 μΜ and 10 mM and in particular between 200 μΜ and 2 mM, and

at least one compound capable of hydrolyzing a silane-based compound in an amount of between 0.1 and 10%, especially between 0.5 and 5% and, in particular, between 1 and 3%,

the percentages being expressed in volume relative to the volume of said solution.

The present invention further relates to a silica particle capable of being prepared by the process of the present invention. This particle is a silica particle comprising at least one phthalocyanine derivative, as previously defined. It differs from the silica particles of the state of the art by the two covalent bonds which bind the silium atom to the phthalocyanine derivative, the phthalocyanine derivative not being a moiety which functionalizes the silica particle. The particle according to the invention is thus distinguished from the silica particles of the state of the art at the structural level precisely because of the bonds covalents participating in the silica network and the central position of the silicon atom. This structural difference results in a high stability of the particles according to the invention thus obtained.

Advantageously, the silica particles according to the invention are nanoparticles having an average size greater than 100 nm. Indeed, the silica particles according to the invention are nanoparticles having an average size greater than or equal to 105 nm, especially between 110 and 600 nm and, in particular, between 120 and 400 nm. The silica particles being advantageously spherical, the sizes previously defined correspond to the average diameter of these particles. The silica particles according to the invention may be optionally functionalized.

In addition, the silica particles according to the invention may be optionally porous. For this purpose, a blowing agent such as those customarily used may be added to the solution (S _a ). As porogenic agents which can be used, mention may be made of glycerol, 3-aminopropyltriethoxysilane,

Octadecyltrimethoxysilane (C18TMS), a platinum precursor, a surfactant such as cetyltrimethoxyammonium bromide (CTAB) or an adamantane type thermal porogen.

The present invention finally relates to the use of a silica particle according to the invention in fields selected from the group consisting of catalysis, printing, paints, filtration, polymerization, heat exchange, thermal stability, material chemistry, hydrocarbon refining, hydrogen production, sorbents, food industry, active agent transport, biomolecules, pharmaceuticals, insulated coatings, bioelectronic compounds and electronic, optical, semiconductor and sensor devices.

Other features and advantages of the present invention will become apparent to those skilled in the art on reading the examples below given for illustrative and non-limiting, and with reference to the appended figure.

BRIEF DESCRIPTION OF THE DRAWINGS

The single FIGURE shows a view obtained by transmission electron microscopy (TEM) of the silica nanoparticles prepared by the process according to the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

I. Process for the preparation of silica nanoparticles according to the invention

The preparation of two solutions is necessary for the experiment, a first solution containing the hydrolysis agent (ammonia) in alcohol and a second ethanolic solution containing the silane derivative of phthalocyanine. The mixture The reaction mixture was prepared by mixing the appropriate amounts of ethanol, water and THF, aqueous ammonia solution and TEOS. Ammonia acts as a reagent (¾0) and as a catalyst (NH ₄ OH) for the hydrolysis of TEOS.

A first solution (1) is generated by adding, in this order, the following chemicals: deionized water (2 mL), ethanol (5 mL), THF (6 mL) and ammonia 25% aqueous (1 mL).

This first solution (1) is added dropwise to a second solution (2) prepared subsequently, with magnetic stirring, and containing, in this order, the following chemicals: the silane derivative of phthalocyanine (silicone dihydroxide naphthalocyanine, CAS No: 92396-90-2) dissolved in THF (10 mg at 775 g mol ^-1 in 1.25 mL THF), ethanol (0.75 mL) and optionally TEOS (0.5 mL , d = 0.934, M = 208.33 g mol ^-1 ).

The second solution (2) contains, in this order, the following chemicals: the silane derivative of phthalocyanine (silicone dihydroxide naphthalocyanine, CAS No: 92396-90-2) dissolved in THF (10 mg to 775 g / mol ^{) 1} in 1.25 mL of THF) and ethanol (0.75 mL) This solution is used for the future.

Alternatively, the solution (2) may contain, in this order, the following chemicals: the silane derivative of phthalocyanine (silicone dihydroxide naphthalocyanine, CAS No. 92396-90-2) dissolved in the THF (10 mg at 775 g mol ^-1 in 1.25 mL THF), ethanol (0.75 mL) and TEOS (0.5 mL, d = 0.934, M = 208.33 g. mol ^"1 ).

Once the addition of (1) was complete, the solution was then stirred at room temperature for 24 hours. The hydrolysis of the silane derivatives (phthalocyanine and TEOS) was initiated by the addition of 25% aqueous ammonia.

The reaction mixture is destabilized by the addition of ethanol (200 ml) and the silica beads obtained are washed three times with ethanol and once with water, each washing being followed by centrifugal sedimentation (15 ml). min at 6000 rpm).

After the washing step, the purification of the nanoparticles obtained was completed by dialysis in water (1 L) with magnetic stirring for one week.

II. Characterization of silica nanoparticles according to the invention.

The silica nanoparticles dispersed in water (10 mL) prepared according to the method of Part I are then characterized by transmission electron microscopy (TEM) analysis which allows to appreciate the nanostructure of these nanoparticles.

Thus, spherical nanoparticles whose diameter varies between 120 and 400 nm are observed (single figure). REFERENCES

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Claims

1) Process for the preparation of a silica particle incorporating at least one phthalocyanine derivative, said particle being prepared from at least one silicone phthalocyanine derivative by hydrolysis of said silicone phthalocyanine derivative in an alcoholic solution,

said silicone phthalocyanine derivative being a compound of formula (I):

(I)

in which :

R5 and R6, which are identical or different, are chosen from the group consisting of -Cl, -F, -OH and -OR 'with R' representing a linear or branched alkyl of 1 to 12 carbon atoms and in particular from 1 to 6 carbon atoms, optionally substituted. 2) Process according to the claim characterized in that said silicone phthalocyanine derivative is a compound of formula (II):

(Π)

in which :

the groups R7 to R22, which are identical or different, are chosen from the group consisting of hydrogen; a carboxylate; an aldehyde; an ester; an ether; a hydroxyl; a halogen; aryl such as phenyl, benzyl or naphthyl; alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted such as methyl, ethyl, propyl or hydroxypropyl; an amine; a friend of ; a sulfonyl; a sulfoxide and a thiol;

the groups R ₅ and R 6 are as defined in claim 1. 3) Process according to claim 1, characterized in that said silicone phthalocyanine derivative is a compound of formula (III) of the naphthalocyanine type:

(III)

in which :

the groups R ₂₃ to R 46, which are identical or different, are chosen from the group consisting of hydrogen; a carboxylate; an aldehyde; an ester; an ether; a hydroxyl; a halogen; aryl such as phenyl, benzyl or naphthyl; alkyl, linear or branched, of 1 to 12 carbon atoms and in particular of 1 to 6 carbon atoms, optionally substituted such as methyl, ethyl, propyl or hydroxypropyl; an amine; a friend of ; a sulfonyl; a sulfoxide and a thiol; the groups R ₅ and R 6 are as defined in claim 1.

4) Method according to any one of claims 1 to 3, characterized in that said method comprises the following successive steps:

a) preparing a first solution (S _a ) containing at least one silicone derivative of phthalocyanine and optionally at least one silane compound,

b) adding, to the solution (S _a ) obtained in step (a), a second solution (S ') comprising at least one compound allowing the hydrolysis of silane compounds and at least one alcohol,

5) Process according to claim 4, characterized in that said solution (S _a ) is obtained, during step (a), by mixing together at least one silicone phthalocyanine derivative, at least one polar solvent and optionally at least one a silane compound.

6) Process according to the claim characterized in that said polar solvent is hydroxylated solvent such as methanol, ethanol and isopropanol.

7) Process according to any one of claims 4 to 6, characterized in that said (or said) compound (s) based on silane is (are) of general formula:

SlR _a RbRcRd

wherein R _a , R _b , R _c and R _d are, independently of one another, selected from the group consisting of hydrogen; a halogen; an amino group; a diamine group; an amide group; an acyl group; a vinyl group; a hydroxyl group; an epoxy group; a phosphonate group; a sulfonic acid group; an isocyanate group; a carboxyl group; a thiol group (or mercapto); a glycidoxy group; an acryloxy group such as a methacryloxy group; an alkyl group, linear or branched, optionally substituted, of 1 to 12 carbon atoms, especially 1 to 6 carbon atoms; an aryl group, linear or branched, optionally substituted, of 4 to 15 carbon atoms, in particular of 4 to 10 carbon atoms; an alkoxyl group of formula -OR _e with R _e representing an alkyl group as defined above and their salts.

8) Process according to any one of claims 4 to 7, characterized in that said (or said) compound (s) based on silane is (are) chosen from the group consisting of dimethylsilane (DMSi) ), phenyltriethoxysilane (PTES), tetraethoxysilane (TEOS), tetramethoxysilane

(TEMOS), n-octyltriethoxysilane, n-octadecyltriethoxysilane, dimethyldimethoxysilane

(DMDMOS), (3-mercaptopropyl) trimethoxysilane, (3-mercaptopropyl) triethoxysilane, (mercapto) triethoxysilane, (3-aminopropyl) triethoxysilane, 3- (2-aminoethylamino) propyltrimethoxysilane,

[bis (2-hydroxyethyl) amino] propyltriethoxysilane,

Hexadecyltrimethoxysilane, phenyltrimethoxysilane, N- [3- (trimethoxysilyl) propyl] -1,2-ethanediamine and acetoxyethyltriethoxysilane, 2-hydroxy-4- (3-triethoxysilylpropoxy) diphenyl ketone, methyltriethoxysilane, vinyltrimethoxysilane; , (3-glycidoxypropyl) trimethoxysilane, (benzoyloxypropyl) trimethoxysilane, sodium 3-trihydroxysilylpropylmethylphosphonate, (3-trihydroxysilyl) -1-propanesulphonic acid,

(diethylphosphonatoethyl) triethoxysilane, and mixtures thereof.

9) Process according to any one of claims 4 to 8, characterized in that said solution (S ') is obtained by mixing together:

optionally at least one non-alcoholic polar solvent,

at least one polar solvent alcoholic and

at least one compound for hydrolyzing the silane compound. 10) Process according to any one of claims 4 to 9, characterized in that said compound for hydrolyzing the silane compound is selected from the group consisting of ammonia, sodium hydroxide (KOH), lithium hydroxide (LiOH), sodium hydroxide (NaOH), triethylamine and pyridine.

11) Solution (S _b ) that can be implemented in the context of a process as defined in any one of the preceding claims, comprising:

one or more polar solvent (s) alcoholic (s),

at least one non-alcoholic polar solvent,

one (or more) phthalocyanine silicone derivative (s) of formula (I) as defined in claim 1,

optionally at least one silane-based compound, and

at least one compound capable of hydrolyzing a silane compound.

12) Solution according to claim 11, characterized in that it comprises:

one or more polar alcoholic solvents in an amount of between 20 and 80% and in particular between 30 and 70%,

at least one non-alcoholic polar solvent in an amount of between 15 and 75% and in particular between 20 and 65%, one (or more) phthalocyanine silicone derivative (s) in an amount of between 10 μΜ and 20 mM, in particular between 20 μΜ and 10 mM and in particular between 200 μΜ and 2 mM,

13) silica particle comprising at least one phthalocyanine derivative capable of being prepared by a process as defined in any one of claims 1 to 10, characterized in that it has an average size greater than or equal to 105 nm , in particular between 110 and 600 nm and, in particular, between 120 and 400 nm.