WO2010038252A2

WO2010038252A2 - Carbonyl derivatives having a c3 symmetry, their preparation and uses thereof

Info

Publication number: WO2010038252A2
Application number: PCT/IT2009/000449
Authority: WO
Inventors: Liliana Bagala^ Rampazzo; Leonardo Matiello
Original assignee: Università Degli Studi Di Roma La Sapienza
Priority date: 2008-10-02
Filing date: 2009-10-02
Publication date: 2010-04-08
Also published as: ITRM20080523A1; WO2010038252A3; IT1391474B1; EP2334630A2

Abstract

The invention relates to 1,3,5-benzene derivatives and corresponding radical-anions and radical-cations of the general formula (I): wherein: Z is a group chosen from among C=O, CONH, CONR, CONAr; m is an integer >0, preferably m = 1; A is a group chosen from among the radicals of: biphenylene, carbazole, fluoranthene, fluorene, dibenzothiofene, dibenzofurane, fluorenone, bifluorenylidene, triphenylene, cyclooctatetraene (COT), dibenzocyclooctatetraene (DBCOT), coronene, acenaphtylene, triptycene, azulene, benzo(ghi)fluoranthene, 2-phenyl-l,3,4-oxadiazole, anthracene. R and Ar are alkyl and aryl respectively and have the meaning indicated herein below. The invention also relates to the method for synthesizing said compounds and to their use in particular as components of matrices in the molecular electronics, spintronics and telecom fields.

Description

"Carbonyl derivatives having a C3 symmetry, their preparation and uses thereof

Field of the Invention

The present invention relates to carbonyl derivatives of benzene having a C3 symmetry and of the general formula (I). The invention also relates to the method for synthesizing said compounds and to their use in particular as components of matrices in the molecular electronics, spintronics and telecom fields.

Prior Art

The components for molecular electronics are very complex and their functioning is based on the combined action of a plurality of components and materials. By way of example, the layers which can be interposed in between the cathode and the anode in a OLED device (Organic Light Emitting Device) are as follows: a layer containing a material suitable for generating positive charges or holes (Hole Injection Material, HIM), a layer containing a material for transporting holes or positive charges (Hole Transport Material, HTM), a layer for emitting fluorescent or phosphorescent light. Such a layer may in turn be made of a plurality of layers containing a material which blocks the electrons (Electron Blocking Material, EBM), a material which emits light (Light Emitting Material, LEM), a material which blocks the holes (Hole Blocking Material, HBM), a layer which contains a material which transports the electrons (Electron Transport Material, ETM).

The electron flow goes from cathode to anode. The materials layered onto the layers may in turn comprise single organic compounds or mixtures of different compounds similar in their nature to each other and which may have the same functions within the layer. From what has been described above, it can be gathered how complex the electronic devices available on the market can be, and how much it is felt the need for having a large range of organic compounds available.

As a matter of fact, often it is not sufficient to use one single organic compound, but it is preferable to have a plurality of compounds available among which to choose those showing such a behaviour as to endow the device with the applicative features required.

By C3 symmetry it is meant a molecular structure which shows a ternary symmetry axis, i.e., that a 120 degrees rotation around the axis which is perpendicular to the plane, in this case benzene, and which passes through its center, can reproduce the molecule itself.

Organic compounds with C3 symmetry are known, e.g., for their applications in electronics (J.A. Joule, Advances in Heterocyclic Chemistry (1984), 35, 83-198; Giebink, N. C; Forrest, S. R. Physical Review B: Condensed Matter and Materials Physics (2007), 76(7), 075318/1-075318/7 Hirota, K. et al. Synthetic Metals 157 (2007) 290- 296).

In particular, the 1,3,5-substituted benzene is known for some of the applications herein claimed (Yamaguchi, Yoshihiro; Ochi, Takanori; Miyamura, Satoshi; Tanaka, Takahiro; Kobayashi, Shigeya; Wakamiya, Tateaki; Matsubara, Yoshio; Yoshida, Zen-ichi. Journal of the American Chemical Society (2006), 128(14), 4504-4505), but none of the compounds described in what follows can be found in the Prior Art.

In the PCT application WO2006005627 a benzene derivative is described with a C3 symmetry and containing three spirobifluorene derivatives. These compounds, anyway, show the drawback that the spiro linkage which is their feature implies non-optimal physical forms for some applications, e.g., a too low glassy transition temperature Tg. These compounds also have E° values which are not compatible with a certain number of applications. For example, their reduction potential is too negative for accepting electrons (at least for the desired objectives for these compounds' applications). For a material to be suitable for being layered onto layer 3, this requisite is least acceptable.

The patent application WO2007/137725 describes compounds characterized by the presence of substituents in the position Y on the Ar. The compounds herein claimed do not show such a well characterized substitution. In addition, exactly for this feature they are particularly suitable, differing in that from the compounds described in WO2007/137725, to yield radical-anions (and radical cations) with a reversible electrochemical behaviour.

Carbonyl derivatives of different types are described in Pigge F. C. et al., Tetrahedron Letters, 42, no. 47, (2001), 8259-8261; Pigge F.C. et al., Tetrahedron Letters, 41, no. 34, (2000), 6545-6549; Pigge F.C. et al., J. Org. Chem., 73, no. 7, (2008), 2760-2767. These compounds are not suitable for the applications mentioned above because of their unsuitable reduction and/or oxidation potentials (E°ox, E°red).

Carbonyl derivatives of benzene with C3 symmetry have now been found which show interesting chemical-physical features in particular for use in the molecular electronics, spintronics and telecom fields, in particular E°red, such to make easier for the molecule to form the radical-anion. Such derivatives are characterized by having all the substituents which are identical to each other.

Summary of the invention

Therefore, the object of the present invention resides in the 1,3,5 derivatives of benzene of the general formula (I):

wherein:

Z is a group chosen from among C=O, CONH, CONR, CONAr; m is an integer >0, preferably m = 1;

A is a group chosen from among the radicals of: biphenylene, carbazole, fluoranthene, fluorene, dibenzothiofene, dibenzofurane, fluorenone, bifluorenylidene, triphenylene, cyclooctatetraene (COT), dibenzocyclooctatetraene (DBCOT), coronene, acenaphtylene, triptycene, azulene, benzo(ghi)fluoranthene, 2-phenyl-l,3,4-oxadiazole, anthracene; with the proviso that the A group does not have arylamine-type and Y-type substituents, with Y having the following core, possibly substituted:

wherein E is C, a heteroatom chosen from among O, S,

N, P, possibly substituted, or a single link.

R and Ar are alkyl and aryl respectively and have the meaning indicated herein below.

Another object of the invention are the radical-anions and radical- cations, in particular mono-, di- and tri-anions and mono-, di- and tri- cations corresponding to the compounds of formula (I). By radical- anions it is meant the chemical species which is obtained by addition of one electron to the corresponding neutral species and, consequently, by radical-cations the chemical species obtained by subtraction of one electron from the corresponding neutral species.

A further object of the invention are the method for synthesizing the compounds of formula (I) and the method for synthesizing their corresponding radical-anions and/or radical-cations, alone or in a mixture thereof. Still a further object of the invention are the compositions comprising the compounds of formula (I) and/or their corresponding radical-anions and/or radical-cations, alone or in a mixture thereof to be employed in the manufacture of electronic components.

Still a further object of the invention are the electronic devices which contain the compounds of formula (I) of the invention and/or the corresponding radical anions and/or radical-cations, alone or in a mixture thereof.

Still a further object of the invention is the use of the compounds of formula (I) and/or of their corresponding radical anions and/or radical- cations, alone or in a mixture thereof, for the manufacture of molecular electronics components, in particular as electron transport compounds in ETM materials.

Further objects of the invention will become apparent from the detailed description of the invention.

Detailed Description of the Invention

Within the scope of the present invention with the term radical-anion a chemical species which has the ability to take an electron while keeping its negative charge and its radical feature is meant. Analogously, a compound which is deprived of one electron, bearing onto it a positive charge, is called radical-cation. The radical-anion and radical-cation species may be obtained by chemical or electrochemical route ["Organic Electrochemistry", 4a Ed., Henning Lund & Ole Hammerich Eds., Marcel Dekker Inc, New York (2001) and "Electrochemical methods", 2a Ed., A.J. Bard, L.R. Faulkner, Wiley, New York (2001)].

A radical-anion has a reversible behaviour when, by inverting the potential sign applied to a suitable value, it yields back the starting compounds (see examples reported in the technical literature cited above). The same is true with the radical-cation.

One of the fundamental layers in an electronic device which uses the compounds according to the invention is the one relating to the electron transport. The material to be layered in this layer should thus be able to easily take up electrons yielding the radical-anions of the molecules involved.

In addition, the compound in its neutral form must have the feature to form good amorphous films with elevated Tg to favour a stable operating condition inside the electronic device in the long run, when used.

The compounds of formula (I) of the present invention are characterized in that the energetic levels which can be obtained are particularly suitable for the claimed applications, especially if referred to taking up of electrons, photoemission, and to solubility in organic solvents in case of amide groups-containing molecules.

The present invention thus relates to a particular class of benzene derivatives with a C3 symmetry, characterized by the presence of C=O, CONH, CONR, CONAr groups interposed in between the benzene and the A groups and represented by the general formula (I).

The molecule is characterized by an high degree of symmetry, being all the A substituents identical to each other.

Within the purpose of the invention, by the term biphenylene a molecular structure of the formula (II) is meant; by the term carbazole a molecular structure of the formula (III) is meant; by the term fluoranthene a molecular structure of the formula (IV) is meant; by the term fluorene a molecular structure of the formula (V) is meant; by the term dibenzothiophene a molecular structure of the formula (VI) is meant; by the term dibenzofurane a molecular structure of the formula (VII) is meant; by the term fluorenone a molecular structure of the formula (VIII) is meant; by the term bifluorenylidene a molecular structure of the formula (IX) is meant; by the term triphenylene a molecular structure of the formula (X) is meant; by the term cyclooctatetraene a molecular structure of the formula (XI) is meant; by the term dibenzocyclooctatetraene a molecular structure of the formula (XII) is meant; by the term coronene a molecular structure of the formula (XIII) is meant; by the term acenaphtylene a molecular structure of the formula (XIV) is meant; by the term triptycene a molecular structure of the formula (XV) is meant; by the term azulene a molecular structure of the formula (XVI) is meant; by the term benzo(ghi)fluoranthene a molecular structure of the formula (XVII) is meant; by the term 2- phenyl-l,3,4-oxadiazole a molecular structure of the formula (XVIII) is meant; by the term anthracene a molecular structure of the formula (XIX) is meant.

(VII)

(XVI) XVII

All the structures shown above may have more than one possible binding position to the central benzentricarbonyl core, some more likely than others by the chemical point of view.

With the proviso that the C3 symmetry be maintained, the A group can be variously substituted and can carry one or more substituents, identical or different from each other, chosen from among: H, OH, COOH, CN, SO₃H, halogen, amino group N(R',R") wherein R' ed R", which are identical or different from each other, have the meaning of R or Ar as indicated below; thio group S-R; R group, O-R, COOR, wherein R = alkyl, oxyalkyl, alkenyl, alkynyl, linear, branched or cyclic, preferably with from 1 to 20 carbon atoms, possibly substituted with halogens, preferably C₁-C₇, more preferably C₁-C₄; Ar group, O-Ar, COOAr, wherein Ar is an aromatic or substituted aromatic group, possibly condensed, possibly containing eteroatoms, being Ar possibly substituted with halogens and/or aliphatic chains R'", wherein R'" = R with R having the meaning mentioned above.

Particularly preferred are the compounds wherein A is: carbazole radical, N-alkyl substituted carbazole (i.e., with an alkyl bound to the N atom), N-phenyl substituted carbazole (i.e., with a phenyl bound to the N atom), N-CN substituted carbazole (i.e., with a cyano group bound to the N atom), C-alkyl substituted carbazole (i.e., with an alkyl bound to the C atom), C-OH substituted carbazole (i.e., with a hydroxyl group bound to the C atom), C-SH substituted carbazole (i.e., with a thiol group bound to the C atom), C-halogen substituted carbazole (i.e., with a halogen bound to the C atom), C-CN substituted carbazole (i.e., with a cyano group bound to the C atom), biphenylene radical, alkyl substituted biphenylene, halogen substituted biphenylene, OH substituted biphenylene, SH substituted biphenylene, CN substituted biphenylene; fluorene radical, 9-alkyl substituted fluorene, 9-CN substituted fluorene (i.e., with a cyano group bound to the C atom at position 9), 9-9'-dialkyl substituted fluorene (i.e., with two alkyl groups bound to C atoms at position 9 and 9'), 9-9' di-CN substituted fluorene (i.e., with two cyano groups bound to C atoms at positions 9 and 9'), alkyl substituted fluorene, CN substituted fluorene; triphenylene and alkyl substituted triptycene; bifluorenylidene and alkyl substituted bifluorenylidene; fluorenone; benzo(ghi)fluoranthene (CAS Registry number 203-12-3), 2-phenyl-l,3,4-oxadiazole, anthracene.

The compounds of the invention can be easily synthesized by means of the Friedel Crafts reaction using e.g. AICI3 as the catalyst or equivalent catalysts. Such reactions are known to the expert in the art and can be carried out starting from compounds which are easily available on the market or are easily synthesized.

A method to synthesize the compounds of the invention comprises the following steps:

(i) starting from 1,3,5 benzenetricarbonyl-trihalogenide, preferably

—trichloride, and placing it in a solvent, preferably an organic sulphide, such as carbon sulphide, together with a stychiometric quantity (e.g., in a 3:1 ratio) of a Lewis acid, preferably aluminium trichloride at a temperature not above 15-20⁰C, preferably in a water/ice bath;

(ii) adding under stirring compound A possibly functionalized, and then heating under a reflux to bring the reaction to completion;

(iii) isolating the final product, generally by adding to the reaction an aqueous diluted solution in a mineral acid, e.g., HCl;

(iv) separating the organic phase and repeating the extractions collecting the extracts which contain the final compound;

(v) purifying the final product by cristallization or solvent evaporation, possibly by submitting it to further subsequent purification steps, e.g., by column chromatography.

The radical-anions of the compounds of the invention can be obtained, preferably by a chemical or an electrochemical route, by adding an electron to the corresponding neutral compound; particularly preferred is the electrochemical route because of its selectivity and ease in carrying it out.

To synthesize di-anion and tri-anion radicals, which can be paramagnetic species, it is sufficient to operate at more negative potentials with respect to those used to obtain the corresponding mono- or di-anions, indicated in the experimental conditions.

The electrochemical method to synthesize radical-anions in general is described in:

- "Organic Electrochemistry", 4th Ed., Henning Lund and Ole Hammerich Eds., Marcel Dekker Inc, New York (2001).

- "Electrochemical methods", 2nd Ed., A.J. Bard, L.R. Faulkner, Wiley, New York (2001).

The optimal conditions to synthesize the desired compounds are within the reach of the technical person in the art.

The compounds of the invention, thanks to the presence of the C=O group directly bound to benzene, more easily give radical-anions with respect to the corresponding compounds wherein C=O is absent.

The molecular structure of the compounds of the invention shows chemical-physical features which are mainly linked to the molecular symmetry class and are particularly interesting for the use in the molecular electronics, spintronics and telecom fields.

The compounds herein described can be used as monomers for the synthesis of oligomers and polymers useful for the applications described above.

The compounds of the invention can find application as coatings or thin films on suitable supports (metal or non-metal) by means of known techniques (chemical, chemical-physical, physical) known to the expert in the art. The electronic devices which incorporate them and/or onto which they are layered carry at least one active layer which comprises at least one compound of the invention, preferably mixtures, possibly comprising radical-anions and/or radical-cations, layered onto said supports.

The compounds can be layered onto the supports of electronic devices by means of sublimation or with deposition techniques in vapour phase (e.g., OVPD-organic vapour phase deposition) or by means of spin- coating or with printing techniques such as offset or ink-jet (all of which are techniques known to the expert in the field).

With the general term of molecular electronics it is meant the technical field wherein organic molecular species can be used for electronic applications, being electroluminescence, photoluminescence and conductivity both of electron and of holes comprised within this definition.

With the general term of spintronics the technical field wherein organic molecular species can be used using the spin properties of electrons which are present in the molecule. In other words, in the electronic devices of the molecular electronics the information is transmitted and stocked by the electricity flow in the form of subatomic particles negatively charged, called electrons, or positively charged, called holes. The zero and one of the binary code of a computer are represented by the presence or absence of electrons in a semiconductor or other material. In the molecular spintronics, the information is stocked and transmitted by using a different property of electrons, i.e., their spin.

The use of the compounds herein claimed allows manufacturing more efficient nanodevices for the applications mentioned above.

Particular aromatic compounds derivatives are among those classes of molecules which can be used instead of inorganic species, mostly in ways which are related to their organic molecular structure, in the arrangement and manufacture of electronic devices. In particular, the compounds mentioned above can be used (non comprehensive list) for the components of: OLEDS, organic semiconductors, field-effect transistors (OFETS), molecular rectifiers, organic molecules for laser applications, organic photovoltaic devices, organic spin valves, solar cells, electrochromic and thermochromic materials, in general for electronic components and devices on a molecular scale, components and devices for gaseous H2 sensors, components and devices for the manufacture, transmission and detection of electromagnetic frequencies also in the field of far infra-red, components and devices for spintronics, for chemical sensors, and for the industrial manufacture of metamaterials in general, useful for the above mentioned applications.

The compounds claimed in the present patent application can be useful as materials which transport negative charges (electrons) or positive charges (holes) or as guest materials in electronic devices. It is therefore claimed the use of the compounds herein described in electronic devices (e.g., OLEDS), i.e., devices for light-emitting diodes based on organic compounds, in particular emitting in the visible, in the blue and green-blue and emitting white light (nowadays used also in television screens), in the OFETS, i.e., field-effect transistors based on organic compounds, integrated circuits based on organic compounds, solar cells based on organic compounds, light-emitting transistors based on organic compounds, light-emitting electrochemical cells, organic photoreceptors and organic laser-diodes, electrochromic materials, organic spin valves, gaseous H2 sensors.

The compounds herein claimed can therefore be used as active means in electroluminescent devices (lasers included) or photovoltaic devices and as materials carrying charges in electroluminescent devices, transistors, photovoltaic devices, in telecom devices, i.e., for the manufacture, transmission and detection of electromagnetic frequencies, and in general for the industrial manufacture of metamaterials useful for the above mentioned applications. The compounds herein described can be used in combination with others as additional species in the manufacture of the above mentioned applications.

It is known that the standard potential E° of an organic molecule shifts itself toward more positive values with respect to a reference molecule when its properties as an electron acceptor are better than those of the reference molecule.

With reference to the derivatives and salts according to the present invention and to their corresponding radical-anions, the standard potential E° shifts itself toward more positive values of a quantity ΔE°.

For example, the increase ΔE° toward more positive potentials with respect to values of corresponding compounds which do not contain the functional group C=O bears the advantage of an energy saving by using the molecules of the invention. The compounds of the invention and the corresponding radical-anions, thanks to the presence of a plurality of conjugated C=O groups, can be advantageously used in the electroluminescence field in general, in particular for light-emitting diodes (OLEDs), more in particular blue light OLEDs, as components of a molecular switching, for non-linear optics, in molecular-based computing systems, in field-effect transistors (FET), in negative differential resistance semiconductors (NDR). Thanks to the presence of a number of conjugated C=O groups, the compounds of the invention allow an easy transfer of more electrons with respect to analogous compounds, thus allowing to obtain anionic species which can be used as molecular magnets.

The following examples are given by way of description of the invention and are not to be considered as limiting its scope. Example 1: Synthesis of benzene-l,3,5-tri-[3-carbonyl-(N-ethyl-)- carbazolel (BTCEC)

328 mg of anhydrous, finely pulverized AlCl₃ (P.F. = 133.30; 2.458 mmol) are added to 181 mg of 1,3,5-benzenetricarbonyl trichloride (P.F. = 265.48; 0.683 mmol) in 5 ml of CS₂ at 0⁰C (water-ice bath). A solution containing 400 mg of N-ethylcarbazole (P.F. = 195.26; 2.049 mmol) in 5 ml of CS₂ is added dropwise under stirring, in a period of time of half an hour, and is left to reach room temperature. Subsequently, it is refluxed and is kept under stirring for further 2 hours. After treatment with water and ice, then with dilute HCl, the organic phase is separated. The organic extracts are pooled, treated with a saturated solution of sodium carbonate, washed with water and dried on anhydrous sodium sulphate. A column chromatography then follows using a mixture of dichloromethane-exane 30% as the eluent (yield D 45%).

¹H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.71 - 7.25 (24H, me, ArH); 4.32 (6H, q, CH₂); 1.37 (9H, t, CH₃).

^!3C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 13.70 (CH₃); 37.81 (CH₂); 108.19; 109.00; 120.07; 120.90; 122.86; 123.12; 123.96; 126.59; 127.74; 128.47; 133.35; 139.48; 140.67; 142.78 (all quaternary aromatic C and aromatic CH groups); 195.07 (CO).

Example 2: Synthesis of benzene-l,3,5-tri-(-2-carbonyl-biphenylene) (BTCB)

96 mg of finely pulverized anhydrous AlCl₃ (P.F. = 133.30; 0.723 mmol) are added to 324 mg of 1,3,5-benzenetricarbonyl trichloride (P.F. = 265.48; 0.219 mmol) in 10 ml of CS₂ at 0⁰C (water-ice bath). A solution containing 100 mg of biphenylene (P.F. = 152.19; 0.657 mmol) in 5 ml of CS₂ is added dropwise under stirring, in a time period of half an hour, and is left to reach room temperature. Subsequently, it is refluxed and kept under stirring for further 2 hours. It is treated with water and ice, then with dilute HCl and the organic phase is then separated. The organic extracts are pooled, treated with a saturated solution of sodium carbonate, washed with water and dried on anhydrous sodium sulphate. A column chromatography then follows using a mixture of dichloromethane-exane 20% as the eluent (yield D

%)

¹H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.24 - 6.68 (me, ArH) 1³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 116.37; 116.96; 118.56;

118.97; 129.12; 129.95; 132.98; 133.94; 136.59; 138.48; 149.58; 150.14;

151.88; 157.06 (all quaternary aromatic C and aromatic CH groups);

193.88 (CO).

Example 3: Synthesis of benzene-l,3,5-tri-(carbonyl-fluoranthene) (BTCFA)

500 mg of fluoranthene (P.F. = 202.25; 2.472 mmol) dissolved in 10 ml of nitrobenzene are added dropwise to 220 mg of 1,3,5- benzenetricarbonyl trichloride (P.F. = 265.48; 0.828 mmol) dissolved in 10 ml of nitrobenzene under stirring.

The reaction vessel is brought to 0⁰C (water-ice bath), then 360 mg of anhydrous finely pulverized AlCl₃ (P.F. = 133.30; 2.719 mmol) are added under stirring.

The reaction is left to come down to room temperature. It is then refluxed and is kept under agitation for further 2 hours.

It is treated with ice and dilute HCl, again under stirring for 10 minutes and the organic phase is separated. A further extraction from the aqueous phase is then carried out. The organic extracts are pooled, they are treated with a saturated solution of sodium carbonate, they are washed with water and are dried on anhydrous sodium sulphate.

A mixture of isomers which can be separated is obtained.

¹H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.57 - 7.24 (me, ArH) 1⁵C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 118.26; 120.80; 120.99; 121.14; 121.59; 122.27; 122.93; 123.42; 125.79; 127.33; 127.48; 127.83; 128.05; 128.14; 128.35; 128.86; 129.21; 129.86; 129.96; 130.18; 132.64; 133.11; 134.12; 134.43; 135.41; 135.65; 137.21; 138.13; 138.89; 139.63; 139.68; 140.31; 141.58; 143.82 (all quaternary aromatic C and aromatic CH); 194.80; 195.26 (CO).

Example 4: Synthesis of TAMPO (Nl,N3,N5-tris(5-(4-metoxyphenvD- l,3,4-oxadiazol-2-yl)benzene-l,3,5-tricarboxamide))

Chemical Formula C₃₆H₂₇NgOg

Molecular Weight 729,65

TAMPO

/V^Λp.Λ^-tπsfS^-methoxyphenylJ-IΛ^xadiazol-Σ-ylJbenzene-I Λδ-tπcarboxamide

2.2 equiv (2.2 mmol; 222.62 mg; MW: 101.19; d = 0.726 g/ml; 306.62 μl) of triethylamine, followed by 0.33 equiv (0.33 mmol; 87.60 mg; MW: 265.48) of 1,3,5-benzenetricarbonyl trichloride in DCM (10 ml) are added to a solution of 2-amino-5-(4-methoxyphenyl)-l,3,4-oxadiazole (1.0 mmol; 191,19 mg; MW: 191.19) in DCM (dichloromethane) (10 ml). Subsequently, the mixture is stirred for 3 hours and the solvent is removed under vacuum. The residue is washed with water and dried under vacuum.

¹H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.29 (3H, s, ArH); 8.18 (3H, s, NH); 7.72 (6H, d, ArH); 7.11 (6H, d, ArH); 3.81 (9H, s, OCH₃). 1³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 55.45 (OCH₃); 114.33, 114.58, 127.60, 128.85, 132.04, 136.23, 151.51, 154.32 (aromatic CH and C_q groups); 163.38 (CONH).

Example 5: Synthesis of TAMPOE - (Nl,N3,N5-trietyl-Nl,N3,N5- tris(5-(4-methoxyphenyl)-l,3,4-oxadiazol-2-yDbenzene-l,3,5- tricarboxamide) .

TAMPOE

W¹.Λ/'.Λ^-triethyl-Λ/¹ ,Λ/³,Λ/⁵-tris(5-(4-methoxyphenyl)-1 ,3,4-oxadiazol-2-yl)benzene-1 ,3,5-tricarboxamide

Chemical Formula: C₄₂H₃₉N₉Og

Molecular Weight: 813,81

To a solution of TAMPO prepared in the preceding Example (180 mg in 10 ml of DMF) a solution of NaOH (29.6 mg) in DMF (5 ml) is added dropwise within 30 min. Then 230.86 mg of iodoethane are added.

The mixture is stirred at room temperature and is followed by TLC until the starting compound (ca. 2-3 h) is used up, it is mixed with water (10 ml) and extracted with 10 ml of CH2CI2.

The organic layer is washed with water (10 ml) for three times and dried with anhydrous potassium carbonate (1 g).

After solvent removal, the residue is purified by column chromatography using a mixture of solvents (acetone and hexane). 1H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.40 (3H, s, ArH); 7.82 (6H, d, ArH); 6.95 (6H, d, ArH); 3.84 (9H, s, OCH3); 3.09 (6H, q, CH₂); 1.38 (9H, t, CH₃). 1³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 14.30 (CH₃); 55.31 (OCH₃); 60.52 (NCH₂); 113.50, 114.19, 122.99, 127.25, 128.74, 130.79, 131.47, 163.23 (aromatic CH and C_q groups); 166.30 (CONEt).

Example 6. Synthesis of T2AA (Nl,N3,N5-tris(anthracen-2-yl)benzene- 1,3,5-tricarboxamide).

Λ/',/V³,N⁵-tπ(anthracen-2-yl)benzene-1,3,5-tncarboxamide

Chemical Formula C₅₁H₃₃N₃O₃

Molecular Weight 735,83

T2AA

2.2 equiv (4.4 mmol; 445.2 mg; MW: 101.19; d = 0.726 g/ml; 613.3 μl) of triethylamine followed by 1.32 equiv (0.660 mmol; 175.2 mg; MW: 265.48) of 1,3,5-benzenetricarbonyl trichloride in DCM (15 ml) are added to a solution of 2-aminoanthracene (2.0 mmol; 386.5 mg; MW: 193.24) in DCM (dichloromethane) (20 ml). Then the mixture is stirred for 3 hours and the solvent is removed under vacuum. The solid residue is washed with water and dried under vacuum. 1H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 9.02 - 7.52 (3OH, me, ArH); 11.22 (3H, s, NH).

¹³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 114.35, 120.57, 123.89, 124.12, 124.41, 124.65, 126.55, 126.85, 127.42, 127.61, 129.02, 129.43, 130.33, 130.51, 134.10, 135.07 (aromatic CH and C_q groups); 163.66 (CONH). Example 7. Synthesis of T2AAE (Nl,N3,N5-tris(anthracen-2-vD- Nl, N3, N5-triethylbenzene-l,3,5-tricarboxamide

A solution of NaH (18 mg) in DMF (10 ml) is added dropwise to a solution of T2AA prepared in Example 6 (100 mg in 10 ml of DMF) in 20 min. Then 128 mg of iodoethane are added. The mixture is stirred at room temperature and is followed by TLC until the starting compounds is used up (ca. 2-3 h), mixed with water (10 ml), and extracted with 10 ml of CH2CI2. The organic layer is washed with water (10 ml) for three times and dried with anhydrous potassium carbonate (1 g), After solvent removal, the residue is purified by column chromatography using a mixture of solvents (acetone and exane).

¹H-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 9.00 - 7.50 (30H, me, ArH); 2.96 (6H, q, CH₂); 1.15 (9H, t, CH₃).

¹³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 12.81 (CH₃); 45.33 (CH₂); 125.59, 125.83, 125.98, 126.14, 126.36, 128.02, 128.17, 129.23, 129.57, 129.64, 130.94, 131.90, 132.04, 135.73, 139.23, 139.34 (aromatic CH and Cq groups); 168.39 (CONEt). Example 8. Synthesis of benzene-l,3,5-triyltris((fluorenon-2- yl)methanone)tricofluorenone

Step 1.

Fluorene l_j

265 mg of anhydrous finely pulverized AICI3 (2.0 mmol) are added to 160 mg of 1,3,5-benzenetricarbonyl trichloride (0.6 mmol) in 10 ml of CS2 at 0⁰C. Then, a solution containing 300 mg of fluorenone (1.8 mmol) in 10 ml of CS2 is added dropwise and is stirred for 30 minutes and the solution is then left to get down to room temperature. The mixture is then heated under reflux and kept stirred for further 3 hours. After treatment with ice, water and dilute HCl, the organic phase is separated. The organic extracts are then treated with a saturated solution of sodium carbonate, washed with water and dried on anhydrous sodium sulphate. The solvent phase is then filtered onto Celite and evaporated under vacuum to yield 362 mg of tricofluorene [benzene-l,3,5-triyltris((9H-fluoren-2-yl)methanone)] (yield 91%). iH-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.53 (s, 3 H, ArH); 8.07 - 7.31 (me, 21 H, ArH); 3.85 (s, 6H, CH₂).

¹³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 36.87 (CH2); 119.86, 125.03, 125.256, 127.12, 128.26, 134.72, 134.76, 138.79, 140.20, 141.62, 143.16, 143.42, 144.50, 146.71 (aromatic CH and C_q groups); 194.89 (CO). Step 2.

A solution of 350 mg of TRICOFl (MW 654.75, 0.53 mmol) in 10 ml of pirydine is stirred with 350 mg of potassium permanganate (MW

153.08, 2.29 mmol) at room temperature for 24 h. The mixture is then partitioned with dilute HCl and dichloromethane and then purified by flash chromatography with chloroform/exane 4:1 as the eluent to yield

320 mg of tricofluorenone (MW 696.70, yield 87%). iH-NMR (CDCl₃, 200 MHz, δ vs SiMe₄): 8.38 (s, 3 H, ArH); 8.05 - 7.32

(me, 21 H, ArH).

¹¹³C-NMR (CDCl₃, 50 MHz, δ vs SiMe₄): 120.58, 121.39, 124.59, 125.46,

130.36, 134.17, 134.23, 134.66, 135.07, 136.83, 137.02, 138.09, 142.99,

148.51 (aromatic CH e C_q groups); 192.18, 193.09 (CO).

Example 9. Process for the synthesis of benze ne- 1,3,5- triyltris(benzorg/u1fluoranthen-6-γl methanone (TRICOB)

benzene-1 ,3,5-triyltris(benzo[gΛ/]fluoranthen-6-ylmethanone)

Chemical Formula: C₆₃H₃₀O₃

Molecular Weight: 834,91

141 mg of finely pulverized anhydrous AICI3 (1.061 mmol) dissolved in 10 ml of CS2 are added to 78 mg of 1,3,5-benzenetricarbonyl trichloride (0.295 mmol) at 0⁰C. Subsequently, a solution containing 200 mg of benzo[g/ιi]fluoranthene (0.884 mmol) in 10 ml of CS2 is added dropwise while stirring within 30 minutes and then left to go down to room temperature (RT).

The mixture is then heated under reflux and kept stirring for further 3 hours. After treatment with ice, water and dilute HCl, the organic phase is separated. The organic extracts are treated with a saturated solution od sodium carbonate, washed with water and dried on anhydrous sodium sulphate. The desired compound is subsequently obtained by column chromatography.

Example 10. Synthesis of radical-anions

The radical anions of the compounds of the invention are preferably obtained by the chemical or the electrochemical route by means of addition of an electron to the corresponding neutral compound; particularly preferred is the electrochemical route due to its selectivity and ease of execution.

To obtain diradical dianions, in cases where this is possible, and which can be paramagnetic species, it is enough to operate at more negative potentials with respect to those used for radical anions and indicated in the experimental conditions.

The general electrochemical method to obtain radical-anions is described in:

"Organic Electrochemistry", 4a Ed., Henning Lund & Ole Hammerich Eds., Marcel Dekker Inc, New York (2001).

"Electrochemical methods", 2a Ed., A.J. Bard, L.R. Faulkner, Wiley, New York (2001).

This method is carried out using an electrochemical cell comprising two sections: an anodic and a cathodic one; in the cathodic one a working electrode and a reference calomel electrode are placed. An aprotic solvent or mixtures of: typically N,N-dimethylformamide, acetonitrile, tetrahydrofuran, N-methylpyrrolidone, dimethyl sulphoxide, preferably N,N-dimethyl formamide, acetonitrile and, particularly preferred N,N- dimethylformamide, is made anhydrous according to the current procedures, and to it a supporting electrolyte, typically tetraethylammonium perchloride, tetrabutylammonium tetrafluoroborate, lithium perchlorate, particularly preferred is tetraethylammonium perchloride, also made anhydrous, is added so that a concentration comprised in between IM and 0.01 M, preferably 0.2M and 0.05M, particularly preferred about 0.1 M is obtained.

The electrolyte solution thus prepared is placed in the cathodic section which is separated from the anodic one by a portion of the same electrolyte solution conveniently gelified and wherein the anode is placed (Pt net). The selected compound is added to the electrolyte solution present in the cathodic section of a divided cell, under nitrogen flux, so that a concentration comprised in between 0.01 M and 1 mM, preferably comprised in between 0.01 M and 0.5 mM, and particularly preferred 1 mM is obtained. In the cathodic section of the cell a reticulated vitreous carbon electrode (RVC) as the cathode and a calomel electrode (SCE) as the reference electrode are placed. In the anodic section of the cell, separated from the cathodic section by means of a gelified electrolyte solution, an electrode, preferably a platinum gauze electrode, is placed. Other electrode materials which can be used to make the working electrodes are: mercury, lead, silver, composite materials based on Ti, conducting carbon materials, carbon-containing conducting materials, chemically modified electrodes, particularly preferred is vitreous carbon due to the following features: wide electrochemical window, low cost, absence of toxicity and ease of use.

The supporting electrolytes which can be used are those which preferably contain: perchloride anions, tetrafluoroborate anions, hexafluorophosphate anions, lithium cations, sodium cations, tetraalkylammonium cations and mixtures thereof; particularly preferred are the perchloride anions and the tetraethylammonium cations.

A convenient voltage is applied in between the electrodes so that the desidered radical-anion is obtained, usually a voltage about 0.2 V more negative than the standard potential E° of the compound to be treated (vs SCE).

The working temperatures can be comprised in between -2O⁰C and +50⁰C; particularly preferred is room temperature. An example of radical anions mono-, di-, tri-, anions is shown in the experimental part and their relative E^c _p/E° are expressed in the following Table 1 and 2. Table 1

Compounds E^c _pi E^cp2 E^cp3

(V vs SCE*) (V vs SCE*) (V vs

SCE*)

-tri-(3-carbonvl-(N-eth vD- -1.72 -2.14 -2.46 carbazole)

Benzene-l,3,5-tri-(2-carbonyl-biphenylene) -1.42 -1.75 -2.24

E^c _pi, E^C _P2, E^C _P3, represent, respectively, the peak potentials detected in the voltammetries and relative to one electron, two electrons and three electrons reception for the compounds indicated. * Saturated Calomel Electrode.

Table 2

Compound E°i* E^C _P2 E^C _P3

(V vs SCE*) (V vs SCE*) (V vs SCE*)

Benzene-1,3,5- -1 20 -1 83 -2.23 triyltris((fluorenon-2- yl)methanone

Fluorenone** -1.39** -2.10** -2 67**

* to illustrate the reversibility feature, at this first stage of reduction it presents with a standard reduction potential (E⁰).

** comparative data regarding fluorenone which show that in the experimental conditions used, fluorenone gets reduced at more negative potentials, confirming that the extended conjugation which is a feature of the structures according to the invention, brings about a lowering (in module) of the reduction potentials, i e. a greater ability to get reduced.

Claims

1. 1,3,5-benzene derivatives and corresponding radical-anions and radical-cations of the general formula (I):

wherein:

A is a group selected among radicals of: biphenylene, carbazole, fluoranthene, fluorene, dibenzothiophene, dibenzofurane, fluorenone, bifluorenylidene, triphenylene, cyclooctatetraene (COT), dibenzocyclooctatetraene (DBCOT), coronene, acenaphthylene, triptycene, azulene, benzo(ghi)fluoranthene, 2-phenyl-l,3,4-oxadiazole, anthracene;

Ar is an aromatic or substituted aromatic group, possibly condensed, possibly containing heteroatoms, Ar possibly being substituted with halogens and/or aliphatic chains R'" wherein R'" = R;

R is alkyl, oxyalkyl, alkenyl, alkynyl, linear, branched or cyclic, preferably with from 1 to 20 carbon atoms, possibly substituted with halogens, preferably C₁-C₇, more preferably C₁-C₄; Ar group, O-Ar,

COOAr; with the proviso that the A group does not carry arylamine and Y type substituents, with Y having the following core, possibly substituted:

wherein E is carbon, a heteroatom chosen from among

O, S, N, P, possibly substituted, or a single link.

2. 1,3,5-benzene derivatives and corresponding radical-anions and radical-cations according to claim 1 wherein A carries one or more substituents identical or different from each other, selected from among: H, OH, COOH, CN, SO₃H, halogen, amino group N(R',R") wherein R' and R", identical or different from each other, have the meaning of R or Ar as indicated below; thiol group S-R; group R, O-R, COOR, wherein R=alkyl, oxyalkyl, alkenyl, alkynyl, linear, branched or cyclic, with from 1 to 20 carbon atoms, possibly substituted with halogens, preferably alkyl C₁-C_n with n integer >0, preferably C₁-C₇, more preferably C₁-C₄; Ar group, O-Ar, COOAr, wherein Ar is an aromatic or substituted aromatic group, possibly a condensed aromatic group, possibly containing heteroatoms, Ar being possibly substituted with halogens and/or R'" aliphatic chains in which R'"=R wherein R have the same meaning as mentioned above.

3. 1,3,5-benzene derivatives and corresponding radical-anions and radical-cations according to claims 1-2 wherein A is selected among: carbazole radical, N-alkyl substituted carbazole, N-phenyl substituted carbazole, N-CN substituted carbazole, C-alkyl substituted carbazole, C-OH substituted carbazole, C-SH substituted carbazole, C-halogen- substituted carbazole, C-CN substituted carbazole, biphenylene radical, alkyl substituted biphenylene, halogen substituted biphenylene, OH substituted biphenylene, SH substituted biphenylene, CN substituted biphenylene; fluorene radical, 9-alkyl substituted fluorene, 9-CN substituted fluorene, 9,9'-dialkyl substituted fluorene, 9,9' di-CN substituted fluorene, alkyl substituted fluorene, CN substituted fluorene; alkyl substituted triphenylene and triptycene; bifluorenylidene and alkyl substituted bifluorenylidene; fluorenone aromatic radical, benzo(ghi)fluoranthene, 2-phenyl-l,3,4-oxadiazole, anthracene.

4. Method for synthesizing the derivatives according to claims 1-3 comprising the following steps:

(i) starting from the 1,3,5-benzentricarbonyl-trihalide, preferably trichloride, placing it in a solvent, preferably an organic sulphide, such as, e.g., carbon sulphide, together with a stoichiometric quantity of a Lewis acid, such as e.g., aluminium trichloride, at a temperature not above 15-20⁰C, preferably in a water/ice bath;

(ii) adding the functionalized compound A under stirring and then heating by refluxing to complete the reaction;

(iii) dissolve the final compound by adding to the reaction an aqueous diluted solution of a mineral acid, for example HCl;

(iv) separating the organic phase and repeating the extraction operations collecting the extracts containing the final compound;

(v) recovering the final product by crystallization or evaporation of the solvent, possibly by carrying out further purifications steps.

5. Electrochemical method for synthesizing the radical anions corresponding to the derivatives according to claims 1-3, characterised in that said derivatives, to be transformed into radical anions, at a concentration between 0.01 M and 1 mM, preferably in between 0.01 M and 0.5 mM, more preferably about 1 mM, are added to an anhydrous aprotic solvent containing a supporting electrolyte, also anhydrous, in order to obtain a concentration of the latter ranging between 1 M and 0.01 M, preferably 0.2 M and 0.05 M, more preferably about 0.1 M; the mixture being then placed in an electrolytic cell and a voltage being applied between the electrodes in order to obtain the desired radical anion.

6. Electronic devices and components, selected among: OLEDS, organic semiconductors, field-effects transistors (OFETS), molecular rectifiers, lasers; organic photovoltaic devices; computational systems on a molecular basis; negative differential resistance semiconductors, molecular magnets, organic spin valves; solar cells; electrochromic and thermochromic materials, for electronic components and devices on a molecular scale; components and devices for H2 gas sensors; components and devices for the production, transmission and detection of electromagnetic frequencies also in the far infrared field; components and devices for spintronics, for chemical sensors and in general metamaterials useful for the applications mentioned above, at least comprising one of the derivatives and corresponding radical- anions and radical-cations according to claims 1-3 and mixtures thereof.

7. Use of the derivatives and corresponding radical-anions and radical-cations according to claims 1-3, alone or in a mixture thereof as negative charge (electrons) or positive charge (holes) transporting materials or as guest materials in electronic devices.

8. Use of the derivatives and corresponding radical anions and radical-cations according to claim 7, wherein said electronic devices are selected among: OLEDS, i.e. devices for light emitting diodes, in particular emitting in the visible, in the blue and green-blue and white light, in particular for television screens; OFETS, i.e. transistors based on organic compounds having a field effect; computational systems on a molecular basis; semiconductors with negative differential resistance; molecular magnets; integrated circuits based on organic compounds; solar cells based on organic compounds; light emitting transistors based on organic compounds; light emitting electrochemical cells; organic photoreceptors and organic laser-diodes; electrochromic materials, organic spin valves, H2 gas sensors.

9. Use of the derivatives and corresponding radical anions and radical-cations according to claims 1-3, alone or in a mixture thereof, as active means in photovoltaic devices and electroluminescent devices, including lasers; and as charge-transporting materials in electroluminescent devices; transistors; photovoltaic devices; telecommunication devices, i.e. for the production, transmission and detection of electromagnetic frequencies; and in general for the industrial manufacture of metamaterials useful for the above mantioned applications.