FR2800081A1 - Purified preparation of homopolymer with N,N'-disubstituted 3,3'-bicarbazyl units involves excluding residues of iron chloride and compounds without substituted units - Google Patents

Abstract

Purified preparation of a homopolymer with N,N'-disubstituted 3,3'-bicarbazyl units involves excluding residues of iron chloride and compounds without the N,N'-disubstituted 3,3'-bicarbazyl units. Purified preparation of a homopolymer of formula (I) involves excluding residues of iron chloride and compounds of formula (II): (Y)m(Re)((B)(Ri))n(B)(Re)(Y)m (I) (Y)m(Re)(B)(Re)(Y)m (II) n = 1-150; m = 0-1; Y = functional group; Re and Ri = 2-18C alkyl, 3-12C aliphatic or aromatic; and B = 3,3'-bicarbazyl N,N'-disubstituted by Ri and Re(Y)m at the terminus. Independent claims are included for an electroluminescent diode including a layer(s) of the material purified as above and a semi-conductor material comprising a material purified as above.

Description

 The present invention relates to purified preparations of N, N'-disubstituted bicarbazyl-based homopolymers, to their process for obtaining and their uses, and to the process for their preparation. particularly in electronics and optoelectronics. The present invention also relates to light-emitting diodes and semiconductor materials that include such homopolymers.

The use of bicarbazyl has been proposed in the optoelectronic industry in order to overcome the drawbacks related to carbazole, the latter having photoactive and electroactive properties which are particularly interesting but which are not stable in the oxidized state, because of the very high reactivity of the oxidized species and, therefore, their degradation (JF A1vMrSE <I> et al., Journal of the </ I> Electrochemical <I> Society: </ I> Electrochemical <I> Science and </ I> Technology, 1975, 1 876 894).

Bicarbazyl results from the coupling at the 3,3 'position of two carbazole rings. It has been shown that such a dimer is particularly stable in the oxidized state (J.F.A.VMROSE <I> et al, </ I> ibid). It emits a blue-violet light (DB ROMERO <I> et al., Advanced </ I> Materials, 1997, 9, No. 15, 1158-1161), a much sought-after color in the fields of on-screen visualization, especially for televisions, and particularly difficult to reach with organic compounds. However, bicarbazyl has limited interest because of its thermomechanical characteristics unsuitable for the preparation of diodes. In particular, parasitic phenomena of crystallization of bicarbazyl occur very rapidly during the operation of the diode, leading ineluctably to the destruction of the device (WS BACSA <i> et al., Journal </ I> of Applied Physics, 1998, 84, 10, 5733-5738).

In order to overcome these problems, E. CLOUTET <I> et al. </ I> synthesized high molecular weight bicarbazyl-octylene homopolymers by oxidative polyboupling of bis (N-carbazolyl) octane with the aid of chloride. ferric, the terminating agent of the coupling reaction being N-octylcarbazole (Synthetic Metals, <B> 1999, </ b> 102, 1302-1303). These homopolymers can be used in the form of films in light-emitting diodes. However, they have the disadvantage, because of their method of preparation, to include ferric chloride residues and to give rise to many crystallization points due to the presence of the N-octylcarbazole dimer. Indeed, the coupling method implemented by E. CLOUTET <I> et al. </ I> (ibid) leads to a mixture of homopolymer and dimer resulting from the homocoupling of N-octylcarbazole, the latter being present at about 20 to 30% by weight. The presence of this dimer in the homopolymer, even in a small proportion, does not make reliable and stable optoelectronic devices: monolayer diodes made from such a material have only a few seconds of life.

The inventors have therefore set themselves the goal of supplying homopolymers based on bicarbazyl which are obtained in purified form, optionally also in isomolecular form, and whose thermomechanical characteristics and luminescence properties allow their use in electronics and optoelectronics. .

The subject of the present invention is thus a purified preparation comprising at least one homopolymer of general formula (I) m '(Re) - [(B) - (Ri)] n- (B) - (Re) - (Y) m excluding ferric chloride residues and the compound of formula (II) (Y) m- - (B) - (Re) - (Y).

 I) in which n is between 1 and 150, m is 0 or 1, Y represents a reactive function, (Re) and represents groups selected from the group consisting of linear or branched alkyl groups comprising from 2 to at 18 carbon atoms, the linear or branched unsaturated aliphatic groups comprising from 3 to 12 carbon atoms and the aromatic groups, and (B) represents 3,3'-bicarbazyl N, N'-disubstituted by the groups (R 1) and by the groups (Re) - (Y) ,, at the chain end.

The ferric chloride and the compound of formula (II) correspond respectively to a residue and a by-product of the synthesis of said homopolymer of formula (I), as will be detailed hereinafter in connection with the description of the process for obtaining purified preparations object of the present invention.

The constituent homopolymers of the purified preparation according to the present invention may have molar masses of between 2000 and 100 000 g / mol, depending on their degree of polymerization and the nature of the (Ri) and (Re) groups.

The groups (R 1) act as spacer arms between the bicarbazyl units. They are attached by each of their ends to the nitrogen carbazolic rings.

When Y is present (i.e., when m is zero), the homopolymers of formula (I) are said to be α, û -difunctionalized, or else telechelic, which gives them the possibility of being able to be coupled together. other polymers suitably functionalized for the synthesis of block copolymers and three-dimensional networks. Indeed, the condensation reaction between the ends Y of the homopolymers of formula (I) and the functional end Z of any homopolymer (I ') can lead to the formation of a triblock copolymer of type (I') - (I) - (I '). The function Z can be chosen, depending on the nature of Y, among condensable functions such as alcohols, acids, esters, acid chlorides, amines, isocyanates, etc. In the case where the homopolymer (I ') has two functional ends Z (in the case of a telechelic polymer), the condensation reaction with the Y ends of the telechelic polymer of formula (I) can lead to a multiblock copolymer of the type [(I) - (I ')] X-, where x is the number of blocks (1) and (I') which make up the copolymer. In the case where the homopolymer has on average more than two functional ends Z, the condensation leads to a three-dimensional network whose meshes consist of polymers (I) and (I ').

The coupling of the homopolymer of formula (I) with other polymers offers the possibility of combining, within the same material, the opto-electrical properties (provided by the homopolymer (I)) with all other properties. physico-chemical (solubility, thermal, mechanical properties ...) provided by the polymer (I ').

According to an advantageous arrangement of the purified preparation according to the present invention, the homopolymers of general formula (I) are in the form of an isomolecular fraction, that is to say in the form of polymers of well-defined and homogeneous chain lengths. within the fraction. This isomolecularity makes it possible to obtain materials whose properties are reproducible which are well film-forming.

The reactive function Y optionally present at the end of the constituent homopolymers of the purified preparation according to the present invention is preferably selected from the group consisting of aldehyde, ester, alcohol, halogen, amine, isocyanate, epoxide, sulfonate, nitrile, acid functions. and acid chloride.

Said unsaturated aliphatic groups present in the homopolymers according to the present invention are preferably dienes comprising from 4 to 8 carbon atoms, while said aromatic groups are, for example, phenyl derivatives and are preferably selected from the group consisting of benzene, biphenyl, diphenylmethane, stilbene, diphenylacetylene and xylene.

According to another advantageous arrangement of the present invention the homopolymers general formula (I) are such that m is equal to 0, (Re) represents an ethyl group and (Ri) represents an n-octyl group.

According to another advantageous arrangement of the present invention the homopolymers general formula (I) are such that m is equal to 1, Y represents ester function -COOCH3, (Re) represents an n-pentyl group and (Ri) represents a n-butyl group .

According to yet another advantageous arrangement of the present invention, the homopolymers of general formula (1) are such that m is equal to 1, Y represents a chlorine atom, (Re) represents an n-pentyl group and (R 1) represents a para-xylene group.

The present invention also relates to a purified preparation as described above, characterized in that it can be obtained by the process which comprises the following steps a) reaction, in a suitable solvent and in the presence of chloride ferric acid, between bis (N-carbazolyl) monomer (Ri) and a terminating agent N - [(Re) (Y),] carbazole, (Re), (Ri), Y and m being as defined in one of any one of the preceding claims, the ratio of molar ferric chloride monomer concentrations (rFe) being in the range of 6 to 8 and the ratio of molar monomer to terminator (rAT) concentrations being about 2, b) treatment of the organic phase obtained with a dilute solution of acid, preferably 0.01 M hydrochloric acid, c) isolation of the homopolymer obtained in unpurified form, comprising ferric chloride residues and compound of formula (He) as defined above, and d) fractionating and isolating the purified homopolymer, by selective precipitation in a solvent / non-solvent mixture of said homopolymer.

During this process, the coupling of the carbazole units gives rise to the formation of bicarbazyl units (B).

Such a process advantageously makes it possible to obtain a polymer free of ferric chloride residues and the compound of formula (11) indicated before, which corresponds to the dimer B - [(Re) - (Y), 12 resulting from the homocoupling of the terminating agent.

Cleared of the dimer, the purified preparation according to the present invention, obtained by the process described above, becomes very easily film-forming and the films have no detectable crystallization point, contrary to that observed with the homopolymers of the prior art ( E. CLOUTET <I> et al., </ I> Synthetic iLletals, 1999, 102, 1302-1303).

According to an advantageous embodiment of the purified preparations according to the present invention, their method of production uses, in step a), a halogenated solvent, for example chloroform.

For the purposes of the present invention, the term dilute solution used during step b) mentioned above, a concentration solution of between 0.005 and 0.1 M.

The process described above can comprise, between steps c), a step of washing the organic phase with distilled water until a neutral pH is reached followed by a step of evaporation of the solvent. The appropriate solvent described in step a) is, for example, chloroform.

According to another advantageous embodiment of the purified preparations according to the present invention, their method of obtaining comprises, after the step, a step e) of selective fractionation by repetition of step d) of precipitation of the homopolymer in a mixture solvent / non-solvent. This step advantageously carried out two to three times. .

Such selective fractionation makes it possible to obtain isomolecular fractions, that is to say of well-defined molar masses, of homopolymer formula (1).

The solvent / non-solvent mixture in which the homopolymer is precipitated in step d) is preferably an 80/20 toluene / methanol mixture by volume. The thermomechanical properties and luminescence properties of the constituent homopolymers of the purified preparations according to the present invention allow their use in the form of diodes in ultra-flat screen-type color display devices.

The present invention therefore relates to a light-emitting diode, characterized in that it comprises at least one layer of a purified preparation according to the present invention.

The purified preparations according to the invention can be used techniques conventionally used in the electronics industry. Thin films of controlled thickness can thus be obtained by evaporation of solvent from a solution of the purified preparation spread on a substrate (conductive or not) by the so-called spin coating technique.

The electrodes used in the diodes according to the present invention are of conventional type, for example in semiconductor glass coated with indium oxide and tin for the anode and magnesium / silver alloy or aluminum for the cathode. The diodes according to the invention may be monolayers, that is to say comprise only the purified preparation according to the invention as electroluminescent material. The diodes according to the present invention may also be multilayer, in which case the diode may comprise several layers of preparations one according to the invention, the same or different from each other, or the layer of p <1 1 </ b> purified preparation according to the invention is used in combination with other electroactive materials conventionally used in diodes.

Whether the diode is monolayer or multilayer, the thickness of each purified preparation layer may be, for example, between 5000 Angstroms and other applications that that of electroluminescence can be envisaged, particularly in the field of electronics .

The present invention therefore also relates to semiconductor materials, characterized in that they comprise at least one purified preparation according to the present invention.

By way of example and without limitation, the semiconductor materials according to the invention can be used in field effect transistors.

Other very diverse applications can also be envisaged for purified preparations according to the invention, in fields such as electronic insulation (passive materials), electro-optics (electrochromic device materials, laser diodes), opto-electronics (photovoltaic systems, photorefractive), opto-optics (active third-harmonic generation systems, photo-luminescent systems, optical pump lasers, passive ultra-violet protection systems).

In addition to the foregoing, the invention further comprises other arrangements which will become apparent from the following description, which refers to examples of obtaining purified preparations according to the present invention, and to the accompanying drawings, in which FIG. 1 represents the 1 H NMR spectrum of the homopolymer of formula 1 prepared according to example 1; FIG. 2 represents the NMR spectrum of the homopolymer of formula 1 prepared according to example 1, FIGS. 3a to 3c represent the chromatograms obtained by steric exclusion chromatography (eluent: THF) for the homopolymer of formula 1 prepared according to Example 1 obtained in raw form (FIG. 3a), the homopolymer of formula 1 obtained in purified form, that is to say after extraction of the dimer (FIG. 3b), and the isomolecular samples obtained after selective fractionation (FIG. 3c). The elution volume (Ve) is represented on the abscissa, the elution being carried out at the rate of 1 ml / min (1 top = ml / min). The ordinates represent the refractive index increment An / OC (n: refractive index, C concentration of the sample), - Figures 4a and 4b represent the solid-state bicarbazyl luminescence spectra (FIG. ) and the homopolymer of formula 1 prepared according to example 1, with a number average molar mass of about 40,000 g / mol, in the solid state (FIG. 4b). The wavelength λ, (in nm) is represented on the abscissa and the absorbance (arbitrary units) is shown on the ordinate.

It should be understood, however, that examples are given solely by way of illustration of the object of the invention, of which they in no way constitute a limitation.

<U> EXAMPLE 1 </ U>: Synthesis of purified preparations according to the invention and their use in a diode.

a) <U> Protocol </ U>.

In a 250 ml bicot flask surmounted by a condenser, 2 g (4.5.l0 "3 mol) of bis (N-carbazolyl) octane monomer, 664 mg (2.25 × 10 -3 mol) of N ethylcarbazole, used as coupling reaction termination agent, and excess ferric chloride 10-Z moles). The molar ratio of monomer and terminating agent (rAT) is therefore 2 and the molar ratio between ferric chloride and monomer (rFe) is 6. Then, under argon, <B> 150 ml distilled chloroform.

After stirring for 3 hours at room temperature, the reaction mixture is treated several times with a dilute hydrochloric acid solution (0.01 M HCl) and washed with distilled water until neutral. The organic phase is dried over Na 2 SO 4 and filtered. The polymer precipitated in a large volume of methanol (volume ratio between the polymer solution and methanol 1/10). The white powder of polymer obtained is filtered on sintered glass and then dried under vacuum. 2.6 g of poly (bicarbazolylene-N, N'-1,8-octylene) α, α-carbazolyl-N-ethyl (compound of formula 1 represented in FIG. 1) are obtained, which corresponds to a quantitative yield. . The chromatogram of this crude polymer, obtained by size exclusion chromatography (eluent: THF), is represented in FIG. 3a, reveals a peak corresponding to the dimer resulting from homocoupling of the terminating agent (N-ethylcarbazole). .

 The homopolymer thus obtained corresponds to the general formula (1) indicated above, in which m is equal to 0, (Re) represents an ethyl group and (R 1) represents an n-octyl group.

The polymer is then treated with a toluene / methanol (that is to say solvent / non-solvent) mixture in an 80/20 volume ratio in order to eliminate the residual dimer resulting from the homocoupling of the terminating agent. . For this purpose, methanol is slowly added in a 2 liter Erlenmeyer flask to a solution of the 1% material in toluene. The addition of the methanol is stopped after the appearance of a disorder. The mixture is then brought back to the limpid state by a slight heating. The medium is then allowed to stand for about two days until a white precipitate corresponding to a purified preparation exclusively comprising a homopolymer of high molar mass (number-average molar mass of 100,000 g / mol, determined by size exclusion chromatography) and of narrow distribution (polydispersity index equal to about 1.4). This homopolymer fraction is recovered and dried under vacuum. No trace of residual dimer resulting from the homocoupling of the terminating agent is detectable by both nuclear magnetic resonance of the proton (FIG. 1) and carbon (FIG. 2) and by steric exclusion chromatography (FIG. 3b). .

The NMR spectra are obtained using a BRUCKER AC 200 device at a frequency of 200 MHz for the proton and 50 MHz for the carbon. Steric exclusion chromatography was performed using a WATERS apparatus equipped with five micro-styragel columns (pores of 10, 104, 10 ', and 100 Angstroms) packed in THF. The solvent flow rate is 1 ml / minute. The measurements are performed at room temperature.

The preceding treatment with the toluene / methanol mixture can be repeated two to three times if it is desired to obtain a selective fractionation of the material; it is thus possible, for the same sample, to obtain three fractions of homopolymers of different molar masses (Mn of 100,000, 000 and 40,000 g / mole) and quasi-isomolecular (index of polydispersity 1 of between 1.4 and 1, 5 as shown in Figure 3c).

The glass transition temperatures of the polymers of these different fractions are all close to 70.degree.

b) <U> Use of purified </ U> preparations <U> obtained in a diode </ U>.

By making spin-on films (or spin coating) from the crude polymer (before extraction of the residual dimer resulting from the homocoupling of the terminating agent) in solution in THF, films having numerous points of crystallization are obtained. because of the presence of the dimer of N-ethylcarbazole. Monolayer diodes made from a material have only a few seconds of life, the emitted light being white.

Cleared of the dimer, the isomolecular fractions of the homopolymer, obtained after extraction in the toluene / methanol mixture, become very easily film-forming and the films have no detectable crystallization point. These films have an absorption whose maximum is at nm and a blue-violet luminescence emission corresponding to a maximum located around 430-450 nm (FIG. 4b), in a manner similar to that observed for bicarbazyl (FIG. 4a). .

 EXAMPLE <U> 2 </ U>: Synthesis of a purified preparation comprising an α, o-difunctionalized homopolymer.

a) <U> Protocol </ U>.

Under the same conditions as in the example but using bis (N carbazolyl) butane as a monomer and carbazole N-substituted with methyl hexanoate as a terminating agent, the following homopolymer is obtained, with a quantitative yield: poly (bicarbazolylene N'-1,4-butylene) α, co-carbazolyl-N-hexanoate methyl. This homopolymer is treated and isolated as described in Example 1. The homopolymer thus obtained corresponds to the general formula (1) indicated above, in which m is equal to 1, (Re) represents an n-pentyl group (- (CHz) 5-), (R1) represents an n-butyl group and Y represents an ester function -COOCH3.

b) Characterization <U> of </ U> the homopolymer.

The ends of the polymer chains can be characterized by 13 carbon NMR on low molecular weight fractions, a characteristic signal of the carbonyl terminal ester functions appearing at 172 ppm.

The glass transition temperature of an isomolecular sample with a molar mass of 50,000 g / mol is close to 150 ° C. EXAMPLE 3 Synthesis of another purified preparation comprising a α-functionalized homopolymer.

Under the same conditions as in Example 1, but using bis (V-carbazolyl) para-xylene as the monomer and the carboxole N-substituted with chloropentyl as the terminating agent, the poly (bicarbazolylene-N) , N'-para-xylylene), α-carbazolyl-N-chloropentyl, which is treated and isolated as described in Example 1.

 The homopolymer thus obtained corresponds to the general formula (1) indicated above, in which m is equal to 1, (Re) represents an n-pentyl group, (R 1) represents a group <I> para </ I> xylene (-CHZ-C6I4-CHz-) and Y represents a chlorine atom.

The glass transition temperature of an isomolecular sample with a molar mass of 70,000 g / mol is close to 180 ° C.

As is apparent from the foregoing, the invention is not limited to those of its embodiments of implementation and application which have just been described more explicitly; it encompasses all the variants that may come to the mind of the technician in the field, without departing from the scope or scope of the present invention.

Claims (1)

 1) purified preparation comprising at least one homopolymer of general formula (1) excluding ferric chloride residues and the compound of formula (11) (#) m- (Re) -1L) - (Re) - ( where n is between 1 and 150, m is 0 or 1, Y represents a reactive function, and (Re) and (Ri) represent groups selected from the group consisting of linear or branched alkyl groups. comprising 2 to 18 carbon atoms, the linear or branched unsaturated aliphatic groups comprising from 3 to 12 carbon atoms and the aromatic groups, and (B) represents 3,3'-bicarbazyl N, N'-disubstituted by groups and by the groups (Re) - (Y) ,,, at the chain end. 2) purified preparation according to claim 1, characterized in that said homopolymer of formula (1) is in the form of an isomolecular fraction. 3) purified preparation according to claim 1 or claim 2, characterized in that said polycondensable function Y is selected from the group consisting of the functions aldehyde, ester, alcohol, halogen, amine, isocyanate, epoxide, sulfonate, nitrile, acid and chloride acid. 4) purified preparation according to any one of the preceding claims, characterized in that said unsaturated aliphatic groups are dienes comprising from 4 to 8 carbon atoms. 5) purified preparation according to any one of the preceding claims, characterized in that said aromatic groups are selected from the group consisting of benzene, biphenyl, diphenylmethane, stilbene, diphenylacetylene and xylene. 6) purified preparation according to any one of the preceding claims, characterized in that, in the formula (1), m is equal to 0, (Re) represents an ethyl group and (R1) represents an n-octyl group. 7) purified preparation according to any one of claims 1 to characterized in that, in the formula (I), m is equal to 1, Y represents an ester function -COOCH3, (Re) represents an n-pentyl group and Ri) represents n-butyl group. 8) purified preparation according to any one of claims 1 to 5, characterized in that, in the formula (I), m is equal to 1, Y represents a chlorine atom, (Re) represents an n-pentyl group and (R1) represents a para-xylene group. 9) purified preparation according to any preceding claim, characterized in that it is obtainable by the method comprises the following steps a) reaction, in a suitable solvent and in the presence of ferric chloride, between a monomer bis (N-carbazolyl) (R 1) and a terminating agent [(Re) (Y) n, J carbazole, (Re), (R 1), Y and m being as defined in any preceding claim, the ratio of the molar concentrations of ferric chloride and of monomer being between 6 and 8 and the ratio between the molar concentrations of monomer and of terminating agent being equal to approximately 2, b) treatment of the organic phase obtained with a dilute acid solution c) isolating the homopolymer obtained in unpurified form, comprising ferric chloride residues and of compound of formula (II) as defined in claim 1, and d) fractionation and isolation of the am purified omopolymer, by selective precipitation in a solvent / non-solvent mixture of said homopolymer. 10) purified preparation according to claim 9, characterized in that said suitable solvent used in step a) is a halogenated solvent. 11) purified preparation according to claim 9 or claim 10, characterized in that, to obtain isomolecular fractions of said homopolymer, said process comprises, after step d), step e) selective fractionation by repetition of the step d) precipitation of the homopolymer in a solvent / non-solvent mixture. 12) purified preparation according to claim 1 characterized in that said step e) is carried out two to three times. 13) purified preparation according to any one of claims 9 to characterized in that said diluted acid solution is a dilute solution of hydrochloric acid. 14) purified preparation according to any one of claims 9 to characterized in that said solvent / non-solvent mixture of said homopolymer is a mixture toluene / methanol 80I20 by volume. 15) Light-emitting diode, characterized in that it comprises at least one layer of a purified preparation according to any one of claims 1 to 8. i6) Semiconductor materials, characterized in that they comprise at least one purified preparation according to any one of claims 1 to 8.