WO2008068258A1

WO2008068258A1 - Composition comprising a carbene and an organic matrix, production method thereof and use thereof

Info

Publication number: WO2008068258A1
Application number: PCT/EP2007/063294
Authority: WO
Inventors: Mathias Destarac; Gérard Mignani; Antoine Baceiredo; Tsuyoshi Kato; Fabien Bonnette
Original assignee: Rhodia Operations; C.N.R.S.
Priority date: 2006-12-06
Filing date: 2007-12-04
Publication date: 2008-06-12
Also published as: FR2909679A1

Abstract

The invention relates to a composition comprising a carbene and an organic matrix or a precursor of this matrix, a method for producing this composition and its use. The invention more particularly relates to the use of this composition as a catalyst for chemical reactions.

Description

COMPOSITION COMPRISING A CARBENE AND AN ORGANIC MATRIX, METHOD FOR PRODUCING THE SAME, AND USE THEREOF

The field of the invention is that of carbene chemistry. The invention relates to a composition comprising a carbene and an organic matrix or a precursor of this matrix, a process for obtaining this composition and its use. The invention relates more particularly to the use of this composition as a catalyst for chemical reactions.

Carbenes are known and developed compounds in organic chemistry and organometallic catalysis. These are very interesting compounds that are used in particular as a catalyst for chemical reactions. Carbenes are also used in polymerization reactions via the opening of carbon or silicone rings as catalysts. For example, the opening of lactides leads to polyesters, that of cyclic silicone oligomers to silicone polymers which are widely used in industry. They also act as transition metal ligands, such as palladium, platinum, rhodium, ruthenium, copper and so on.

The carbenes are sought, in particular in coordination chemistry and in organic synthesis. However, these compounds are very reactive with respect to water, alcohols, acids, oxygen etc., and it is therefore difficult to handle them in ambient air. Complex and constraining methods are currently used to manipulate them. It is necessary to use strictly anhydrous storage atmospheres which requires expensive specific equipment. For example, it is possible to use glove boxes or any other facility that can store and use these carbenes. Argon and nitrogen are the most commonly used inert gases. It is therefore sought to facilitate the handling of carbenes, in order to develop their use on a large scale.

For this purpose, the invention provides, in a first object, a composition comprising a carbene and an organic matrix or an organic matrix precursor, the composition having a duration di / ₁ 0 greater than or equal to 24 hours, di / ₁ 0 being the time corresponding to the degradation, by hydrolysis with ambient air, of 10% (molar) of the carbene initially present in the composition.

By carbene is meant a chemical species, generally neutral electronically, comprising a divalent carbon which carries two non-binding electrons ("electron doublet"). The two non-binding electrons can be: either paired in the same orbital (these are singular carbenes), or in two separate orbitals (these are triplet carbenes). Preferably the carbene is a singlet carbene. The divalent carbon of a carbene is most often surrounded by six valence electrons, and not loaded electronically. However, in the sense used herein, the concept of carbene also includes compounds of the aforementioned type where the divalent carbon carries an additional electronic doublet or is engaged in a delocalized bond and / or where the divalent carbon carries an electric charge (typically a negative charge possibly delocalized).

The duration di / ₁ 0 corresponding to the duration of the degradation, by hydrolysis in ambient air, of 10% (molar) of the carbene present initially in the composition, is determined using the degradation monitoring method. carbene in the composition of the invention described below. Advantageously the duration di / ₁ 0 is greater than or equal to 48 hours, preferably greater than or equal to 1 week.

When the organic matrix is a polymer, the precursor of the organic matrix may be a monomer of this polymer.

The organic matrix may be a polymer or any other organic compound such as a composition comprising a carbene and this compound has a duration di / ₁ 0 as defined above greater than or equal to 24 hours.

According to a particular embodiment of the invention, the organic matrix is a polymer. Advantageously, the organic matrix or the precursor is chosen from polyorganosiloxanes, organosiloxanes, linear or cyclic polysilanes, silanes such as alkoxysilanes, alkoxyalkylsilanes, etc., PMMA, ethylcellulose, cellulose acetate, fluorinated polymers such as fluorinated polyolefins (exemplified by fluorinated polethers). As an example of an organosiloxane, mention may be made of octamethylcyclotetrasiloxane (D ₄ ) or hexamethylcyclotrisiloxane (D ₃ ).

The carbene of the invention advantageously corresponds to the general formula (I) below:

(R ^X ) _nx- 1 - X - C - Y - (R ^Y ) ny-1 (I)

wherein: • X and Y, identical or different, are atoms selected from the group consisting of C, N, S, P, Si and O;

• nx and ny are two integers, respectively equal to the valency of the atom X and the valence of the atom Y [ie 2 when the atom is S or O; 3 when the atom is N or P; and 4 when the atom is Si or C]; Each of the groups R ^x and R ^γ linked to the atoms X and Y represents, independently of the other groups, a hydrocarbon chain, aliphatic or aromatic, linear or branched, optionally cyclized in whole or in part, and optionally substituted, it being understood that groups R ^x carried by the atom X and one of the groups R ^γ carried by the atom Y may optionally be bonded together to form a ring with the X and Y atoms and the formally divalent carbon of the carbene [the ring thus formed comprising if appropriate, preferably 5 to 7 members].

Preferably each of the groups R ^x and R ^γ linked to the atoms X and Y represents, independently of the other groups, a hydrocarbon chain selected from the group comprising: an alkyl, alkenyl or alkynyl group, linear or branched, optionally substituted, for example with at least one perfluoroalkyl group, a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example with at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by at least one alkyl or alkoxy group;

According to a particular embodiment of the invention, X denotes a nitrogen atom. Advantageously, the carbene of the invention corresponds to the general formula (1-1) or (I-1 ') below:

R ¹ R ¹

(RY) ny-2 (1-1) ^{K) n} v- ² (1-1 ')

in which :

Y is a heteroatom selected from N, S, P, Si and O, Y being preferably a nitrogen atom;

Ny and R ^γ are as defined in claim 3; and • R ¹ denotes a hydrocarbon chain, linear or branched, optionally cyclized in whole or in part, and optionally substituted, this chain preferably being: an alkyl, alkenyl group - for example allyl or alkynyl, linear or branched, optionally substituted, for example by at least one perfluoroalkyl group, a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example with at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by an alkyl or alkoxy group

A denotes a nitrogen atom or a group CR ^lla , B denotes a nitrogen atom or a group CR ^IIIa ,

• R "and R ¹ ", and; where appropriate, R ^11a and R ^11a , identical or different, each denote a hydrogen atom, or a hydrocarbon chain, linear or branched, optionally cyclized in whole or in part, and optionally substituted, this chain being preferably: an optionally substituted linear or branched alkyl, alkenyl or alkynyl group, for example by at least one perfluoroalkyl group, the tert-butyl, isopropyl, propyl (nPr), butyl (nBu) and methyl groups being particularly preferred a linear or branched perfluoroalkyl group; ; a cycloalkyl group, optionally substituted, for example with at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, in particular by at least one alkyl or alkoxy group.

Preferably the carbene has the general formula (1-1a) or (1-1a ') below: R ¹ R ¹

in which :

R ¹ , R ", R" ^a , R '"and B are as defined in claim 7, and

• R ^ιv denotes a hydrocarbon chain, linear or branched, optionally cyclized in whole or in part, and optionally substituted, this chain preferably being: a linear or branched, optionally substituted alkyl, alkenyl or alkynyl group, for example by at least one group perfluoroalkyl, the tert-butyl, isopropyl, propyl (nPr), butyl (nBu) and methyl groups being particularly preferred a linear or branched perfluoroalkyl group; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, in particular with at least one alkyl or alkoxy group According to another particular embodiment of the invention, the carbene is a compound chosen from the following compounds:

Phosphino (amino) carbenes of formula (II):

(H) bisphosphinocarbenes of formula (III)

Carbodiphosphoranes corresponding to one of the following mesomeric formulas (IV) or (IV)

(IV) (IV)

where each of the groups R, R _P , R _P ¹ , R _P ² , R _P ³ , R _P ⁴ , R _N , and R _P 1 represents, independently of the other groups, a hydrocarbon chain, linear or branched, optionally cyclized into all or part, and optionally substituted, this chain being preferably: an alkyl, alkenyl or alkynyl, linear or branched optionally substituted, for example by at least one perfluoroalkyl group, - a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by at least one alkyl or alkoxy group, it being understood that, in each of the formulas (II), (III), (IV) and (IV), the group R and the group R ^p may optionally be bonded together to form a heterocycle with the two heteroatoms to which they are bonded and the divalent carbon [the heterocycle thus formed having, if appropriate, preferably from 5 to 7 members].

The proportion of carbene in the composition of the invention is advantageously between 0.1 and 50% by weight relative to the weight of the composition, preferably between 1 and 30%.

The composition of the invention may be in any form known to those skilled in the art. However, shapes that allow easy manipulation of the composition are preferred. The latter is advantageously in the form of a solution, a liquid dispersion or a solid mixture. The invention also relates, in a second object, to a process for preparing the composition comprising a step of mixing the carbene (or a precursor) and the organic matrix or the organic matrix precursor. If a carbene precursor is used, for example the imidazolium salts, a strong base such as potassium tert-butoxide or a mixture of potassium tert-butoxide and sodium hydride is generally added.

This mixing step can be carried out according to any method known to those skilled in the art. The mixture is generally carried out at room temperature.

According to a particular embodiment of the invention, the process comprises a step of polymerizing an organic matrix precursor in the presence of a carbene or a precursor. According to this embodiment, the polymeric organic matrix is prepared in situ in the presence of carbene. This embodiment makes it possible to prepare a homogeneous composition. By varying the degree of progress of the polymerization reaction, polymers of different viscosities, and thus a variable viscosity composition, are obtained. This simple, inexpensive process, and using industrial raw materials, is therefore flexible since it makes it possible to obtain a wide range of viscosity levels of the composition. The desired viscosity of the composition varies depending on the subsequent use of the composition. In general, a low viscosity composition is desired, giving an easy flow, for example less than 10,000 centipoise, which allows easy handling. The invention also relates, in a third subject, to the use of the composition of the invention as a catalyst for chemistry reactions. Indeed the composition of the invention can intervene, as well as a single carbene, in the chemistry reactions. The advantage of using the composition of the invention with respect to the carbene alone is that the composition can be easily handled in the ambient air, without any particular precaution, which is not the case of the carbene alone, which is very responsive. Indeed the organic matrix plays a protective role of the carbene vis-à-vis the moisture and / or oxygen of the air, and / or vis-à-vis the liquid water. In addition, the presence of the organic matrix does not affect the reactivity of the carbene of the composition in the chemical reactions in which the carbenes intervene. This represents a considerable advantage. After chemical reaction involving the carbene composition of the invention, the organic matrix of the composition can easily be removed, for example by distillation, extraction or decantation, the reaction medium. This is particularly the case of a polysiloxane matrix.

Advantageously, the composition of the invention is used as a catalyst for reactions of the polymerization of organosiloxanes, cyanosilylation of aldehydes, transesterification, polymerization via the opening of rings such as lactides, lactones and caprolactones. cyclic anhydrides.

The carbene in the composition of the invention can also be used, as well as carbene alone, as ligand of organometallic complexes.

Other details or advantages of the invention will appear more clearly in view of the examples given below.

Method for monitoring the degradation of the carbene in the composition The composition is placed in ambient air (20 ^° C.) in a closed bottle. The monitoring of the degradation of the carbene is carried out by opening the flask, taking a sample and then analyzing it by proton NMR in distilled solvent C ₆ D ₆ (10% by weight of composition in C ₆ D ₆ distilled on sodium - <100 ppm water-). The analyzes are carried out in 16 scans with a field of 300.13 MHz at 298.6 ° K. The calculation of the degradation of the carbene in the composition is carried out by comparing the integrations of the signal corresponding to one or more characteristic protons to the two protons of the degradation product by hydrolysis or oxidation of the carbene (generally the degradation product corresponds to the opening of the carbene ring with the formation of an imine-amide or amine-amide) and proton signal that are carried by the carbene; whether it is hydrolyzed or not. By relative integration, the monitoring of carbene degradation is carried out. For example, in the case of 1, 3-carboxy-2-ylidene carbol, the degradation product by hydrolysis is 1,4-di (tert-butyl) -4-formyl-1,4-diaza. -but-1-ene, we compare the integrations of the doublet at 4.15 ppm representing the two protons of the produced carbene hydrolysis and the singlet at 1, 4 ppm corresponding to protons of ter-Butyl carried by the carbene.

EXAMPLES

EXAMPLE 1 Synthesis of 1,3-diisopropylimidazol-2-ylidene

2 g of 1,3-diisopropylimidazolium tetrafluoroborate (8.3 mmol) are introduced into a Schlenk and 220 mg of sodium hydride (9.2 mmol) and 47 mg of potassium tert-butoxide (0.4 mmol). 15 ml of THF are then introduced into the Schlenk, with the appearance of a strong release of gas. The reaction medium is stirred for 24 hours at room temperature (formation of a precipitate) and then filtered. The filtrate is drawn to dryness and the residue is distilled under reduced pressure. 600 mg of carbene in the form of a slightly orange liquid are obtained (yield = 45%). ¹ H NMR (C ₆ D ₆ ) δ (ppm): 6.55 (s, 2H); 4.41 (sep, 2H, J = 6.7 Hz); 1.25 (d, 12H, J = 6.0 Hz).

NMR ¹³ C (C ₆ D ₆ ) δ (ppm): 211.6 (C _carbo ne); 116.3 (C = C); 52.8 (i-pr) 24.9 (Me).

EXAMPLE 2 Synthesis of 1,3-diterbutylimidazol-2-ylidene

To a solution of 1,3-di-tert-butylimidazolium chloride (9.22 mmol, 2 g) in 15 mL of THF is added, dropwise at -78 ° C, 13.8 mmol of n-BuLi (8.7 mL of a 1.6M solution in hexane). The reaction medium is stirred at -78 ° C. for 30 min and then left to return to ambient temperature. Stirred at room temperature until the end of gassing (2h). The medium is then placed under vacuum to remove the volatiles and the carbene is purified by sublimation. 1.4 g of a white crystalline powder are obtained (yield = 84%). ¹ H NMR (C ₆ D ₆ ), δ (ppm): 6.77 (s, 2H, CH); 1, 51 (s, 18H, t-Bu).

¹³ C NMR (C ₆ D ₆ ), δ (ppm): 212.2 (carbene); 114.7 (C = C); 55.5 (t-Bu); 31.1 (Me).

EXAMPLE 3 Preparation of a Composition with 1,3-Diterbutylimidazol-2-ylidene

Operating mode:

In a glovebox, 300 mg (1.66 mmol) of the 1,3-tert-butylimidazol-2-ylidene obtained according to Example 2 are introduced into a small Schlenk tube. Then 2.06 ml (6.65 mmol) of octamethylcyclotetrasiloxane (D ₄ ) are added at room temperature.

With stirring, 3.5 μl (0.0166 mmol) of hexamethyldisiloxane (M ₂ ) are added.

The medium is closed and then heated at 80 ^° C. for 16 hours. After cooling, the reaction medium (oil) is transferred to air in a closed bottle.

Performed analyzes:

NMR (C ₆ D ₆ ) δ (ppm): 6.36 (s, 2H), 1.40 (s, 18H). The carbene concentration is calculated by relative integration of the singlet at 1.4 ppm corresponding to the protons of tert-Butyl carried by the carbene while the integration of 0.195 to 0.30 ppm represents the dimethylsiloxane unit.

Thus, the carbene concentration is 0.859 mmol / g, ie 154 mg / g of matrix.

EXAMPLE 4 Preparation of a Composition with 1,3-Diterbutylimidazol-2-ylidene

Operating mode:

5 g of paraffin ([CAS]: 8042-47-5, highly hydrocracked white paraffinic mineral oil) are solubilized in 15 mL of pentane. Three washes with 10 mL of water are made. The phase containing the pentane is dried over MgSO ₄ and then filtered. The pentane is evaporated under reduced pressure. 5 ml of distilled toluene are added and then evaporated. This last operation is performed three times. Then, 1.5 g of paraffin are introduced under argon in a Schlenk and 150 mg (0.84 mmol) of 1,3-diterbutylimidazol-2-ylidene are added. After homogenization, the reaction medium is transferred to air in a bottle which is then closed.

EXAMPLE 5 Preparation of a Composition with 1,3-Diterbutylimidazol-2-ylidene

Operating mode: 1.5 g of a polyorganosiloxane of the general formula Me ₃ SiO- (SiMe ₂ O) ₆₆ (SiMePhO-) _7, iSiMe ₃ ("MDD ^ph -M") are introduced into a Schlenk under argon. 5 ml of toluene are added and then the toluene is evaporated under reduced pressure. This operation is repeated three times. Then 150 mg (0.84 mmol) of 1,3-tert-butylimidazol-2-ylidene are added with stirring. After homogenization, the reaction medium is transferred to air in a bottle which is then closed.

EXAMPLE 6 Preparation of a Composition with 1,3-Diterbutylimidazol-2-ylidene

Operating mode:

1.5 g of a polyorganosiloxane of general formula Me3SiO- (SiMe ₂ θ-) ₄ SiMe3 ("MD ₄ -M") are introduced into a Schlenk. 5 ml of toluene are added and then the toluene is evaporated under reduced pressure. This operation is repeated three times. Then, 150 mg (0.84 mmol) of 1,3-tert-butylimidazol-2-ylidene are added with stirring. After homogenization, the reaction medium is transferred to air in a bottle which is then closed.

EXAMPLE 7 Preparation of a composition with the 1, 3-di / ^{'sopropylimidazol-2-} ylidene:

Operating mode:

400 mg of 1,3-diisopropylimidazol-2-ylidene (2.65 mmol) obtained according to the example

1 are added dropwise to 3.57 g of D ₄ (12 mmol). The reaction medium takes up rapidly. Then, it is stirred for 16 hours at room temperature and becomes an oil. The reaction medium (oil) is then transferred to air in a closed bottle.

Performed analyzes:

NMR (C ₆ D ₆ ) δ (ppm): 6.50 (s, 2H); 4.38 (Sep, 2H, J = 6.7 Hz); 1, 26 (d, 12H, J = 6.0 Hz).

The carbene concentration is calculated by relative integration of the doublet at 1.26 ppm corresponding to the carbene-borne protons of / s-propyl while the integration of 0.195 to 0.30 ppm represents the dimethylsiloxane unit.

Thus, the carbene concentration is 0.49 mmol / g, ie 74 mg / g of matrix.

EXAMPLE 8 Comparative Stabilities of a Composition Comprising 1,3-Diterbutylimidazol-2-Ylidene and Solid 1,3-Diterbutylimidazol-2-Ylidene Only: The Carbene Degradation of the Composition of Example 3 is Followed by method described above as well as that of carbene crystals (as comparative).

The results are shown in Table 1 below.

Table 1

EXAMPLE 9 Comparative Stabilities of a Composition Comprising 1,3-Diterbutylimidazol-2-ylidene and Solid 1,3-Diterbutylimidazol-2-ylidene Only

The carbene degradation of the composition of Example 4 is followed according to the method described above as well as that of carbene crystals (as comparative).

The results are shown in Table 2 below.

Table 2

EXAMPLE 10 Comparative Stabilities of a Composition Comprising 1,3-Diterbutylimidazol-2-ylidene and Solid 1,3-Diterbutylimidazol-2-ylidene Alone

The carbene degradation of the composition of Example 5 is followed according to the method described above as well as that of carbene crystals (as comparative).

The results are shown in Table 3 below.

Table 3

EXAMPLE 11 Comparative Stabilities of a Composition Comprising 1,3-Diterbutylimidazol-2-ylidene and Solid 1,3-Diterbutylimidazol-2-ylidene Alone

The carbene degradation of the composition of Example 6 is followed according to the method described above as well as that of carbene crystals (as comparative).

The results are shown in Table 4 below.

Table 4

EXAMPLE 12 Reactivity of the Composition Comprising 1,3-Diterbutylimidazol-2-

67 mg of the composition of Example 3 formed since 1 day (48 micromoles) are introduced into a Schlenk previously dried and put under argon. Then, 3 mL of D ₄ (9.69 mmol) are added at room temperature. The reaction medium is brought to 80 ° C with stirring for 16 hours. The reaction medium is then analyzed by GPC.

163 mg of carbene encapsulated for 1 week (1 16.7μmoles) are introduced into a Schlenk previously dried and put under argon. Then 7.25 ml of D ₄ (23.35 mmol) are added at room temperature. The reaction medium is brought to 80 ⁰ C with stirring for 16 hours. The reaction medium is then analyzed by GPC.

Results: time (days) conversion (% r Mn (g.mol ^"1 ) Ip

1 88 100723 1, 57

7 86 94445 1, 62 a) calculated by GPC

The reactivity of the composition of Example 3 is comparable to that of carbene alone.

EXAMPLE 13 Reactivity of the Composition Comprising 1,3-Diterbutylimidazol-2-ylidene in the Pvaldéhvde Cvanosililation Reaction

166 mg of the composition according to the example formed for 23 days (80 μmol) are introduced into a Schlenk previously dried and put under argon. In a second Schlenk, 950 μl of Pdealdehyde (8.53 mmol) are introduced and then 5 ml of

THF and finally 1, 13 mL (8.53 mmol) of trimethylsilylcyanide. The content of the second

Schlenk is immediately cannulated in the first Schlenk. After stirring for 10 minutes at room temperature, the volatiles are removed by evaporation under reduced pressure. The expected product is then purified by distillation. 1.36 g of a colorless liquid are obtained (yield = 86%).

¹ H NMR (CDCl ₃ ) δ (ppm): 3.98 (s, 1H); 1.00 (s, 9H); 0.19 (s, 9H). ¹³ C NMR (CDCl ₃ ) δ (ppm): 19.29 (CN); 70.82 (CH); 35.79 (f-Bu); 24.92 (SiMe ₃ ).

EXAMPLE 14 Reactivity of the Composition Comprising 1,3-Diterbutylimidazol-2-ylidene in the Transesterification Reaction

69 mg (50 μmol) of the composition according to Example 3 formed for 25 days are introduced into a Schlenk then 0.8 g of 4 A molecular sieve and 1.7 mL of THF. 116 μl of methyl acetate (1.68 mmol) are added and then 190 μl of benzyl alcohol (1.68 mmol) are added dropwise. The reaction medium is stirred at room temperature for 3 days. Volatiles are removed under reduced pressure then the residue is distilled to obtain the expected product as a colorless liquid with a yield of 84%.

¹ H NMR (CDCl ₃ ), δ (ppm): 7.3-7.1 (m, 5H); 5.00 (s, 2H); 1, 98 (s, 3H).

¹³ C NMR (CDCl ₃ ), δ (ppm): 170.9 (C = O); 136.0 ( _Clpo ); 128.6 (C _aro ); 128.5 (C _aro ); 128.3 (C _aro ); 66.3 (CH ₂ ); 21, 0 (Me).

The reactivity of the composition according to Example 3 is comparable to that of carbene alone.

EXAMPLE 15 Reactivity of the Composition Comprising 1,3-Diterbutylimidazol-2-ylidene in the Organometallic Complexation Reaction with Palladium (II)

316 mg of the composition according to Example 3 formed for 23 days (0.25 mmol) are introduced into a Schlenk previously dried and put under argon. Then 3 ml of THF are added. 45.5 mg of palladium dimer (0.125 mmol) are then introduced into the schlenk. The reaction medium is stirred at room temperature for 1 h 30. Then, the volatiles are removed under reduced pressure. The residue is washed twice with 10 ml of pentane. 81 mg of the expected composition are obtained in the form of a beige powder (yield = 93%).

¹ H NMR (C ₆ D ₆ ) δ (ppm): 6.61 (s, 2H); 4.90 (m, 1H); 4.17 (dd, 1H, J = 2.4 Hz, J = 7.4 Hz); 3.35 (d, 1H, J = 13.2 Hz); 3.04 (d, 1H, J = 6.9 Hz); 2.00 (d, 1H, J = 12.0 Hz); 1, 67 (s, 9H); 1, 48 (s, 9H).

¹³ C NMR (C ₆ D ₆ ), δ (ppm): 178.1 (C _carb ); 118.0 (C = C); 117.6 (C = C); 68.23 _(C ,, _yl); 58.2 (C (CH ₃ ) ₃ ); 58.1 (C (CH ₃ ) ₃ ); 51.0 (C _a , _yl ); 31, 6 (ffiu); 31, 3 (ffiu).

EXAMPLE 16 Reactivity of the Composition Comprising 1,3-Diterbutylimidazol-2-

371 mg of the composition according to Example 3 formed for 23 days (0.29 mmol) are introduced into a Schlenk previously dried and put under argon. 1.5 ml of toluene are then added. The reaction medium is brought to 0 ^° C. and then 353 μl of a 16.5% solution of platinum in polydimethylsiloxane (0.29 mmol) are added dropwise. The reaction medium is stirred for 16 hours at room temperature, forming a white precipitate. The reaction medium is drawn to dryness and then washed with twice 10 ml of pentane. 112 mg of expected product are obtained in the form of a white powder (yield = 64%). ¹ H NMR (CDCl ₃ ) δ (ppm): 7.17 (s, 2H); 2.19 (dd, 2H, J = 11.1Hz, J = 54.0Hz); 1.90-1.70 (m, 4H); 1.53 (s, 9H); 1.43 (s, 9H); 0.24 (s, 3H); -0.35 (s, 3H).

¹³ C NMR (CDCl ₃ ), δ (ppm): 181.2 (C _carb ); 118.2 (C = C); 117.4 (C = C); 58.8 (C (CH ₃ ) ₃ ); 58.5 (C (CH ₃ ) ₃ ); 46.7 (Si-C, J = 184.5 Hz); 31.8 (C = C, J = 123.7 Hz); 31.0 (ffiu); 30.7 (tBu); 1.6 (Me); -2.7 (Me).

Claims

1. A composition comprising a carbene and an organic matrix (or an organic matrix precursor), the composition having a duration di / ₁ 0 greater than or equal to 24 hours, di / ₁ 0 being the duration corresponding to the degradation, by hydrolysis to the ambient air, 10% (molar) of the carbene initially present in the composition

2. Composition according to claim 1, characterized in that di / ₁ 0 is greater than or equal to 48 hours

3. Composition according to claim 1 or 2, characterized in that the organic matrix is a polymer

4. Composition according to one of the preceding claims, characterized in that the organic matrix or the precursor is chosen from polyorganosiloxanes, organosiloxanes, polysilanes, silanes, PMMA, ethylcellulose, cellulose acetate, fluorinated polymers such as fluorinated polyolefins.

5. Composition according to one of the preceding claims, characterized in that the carbene comprises, in α of its divalent carbon, a heteroatom selected from N, S, P, Si and O

6. Composition according to one of the preceding claims, characterized in that the carbene corresponds to the general formula (I) below:

(R ^X ) _nx- 1 - X - C - Y - (R ^Y ) ny-1 (I)

7. Composition according to claim 6, characterized in that each of the groups

R ^x and R ^γ linked to the atoms X and Y represents, independently of the other groups, a hydrocarbon-based chain chosen from the group comprising: an optionally substituted linear or branched alkyl, alkenyl or alkynyl group, for example by at least one perfluoroalkyl group, a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by at least one alkyl or alkoxy group;

8. Composition according to claim 6 or 7, characterized in that X denotes a nitrogen atom.

9. Composition according to one of the preceding claims, characterized in that the carbene corresponds to the general formula (1-1) or (1-1 ') below:

R ¹ R

( ^R ) n-2 Ji- ₁ J ( ^R ) n-2 ^ _-1 , j

in which : Y is a heteroatom selected from N, S, P, Si and O, Y being preferably a nitrogen atom;

Ny and R ^γ are as defined in claim 3; and

• R ¹ denotes a hydrocarbon chain, linear or branched, optionally cyclized in whole or in part, and optionally substituted, this chain preferably being: an alkyl, alkenyl group - for example allyl or alkynyl, linear or branched, optionally substituted, for example by at least one perfluoroalkyl group; a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by an alkyl or alkoxy group;

• A denotes a nitrogen atom or a group CR ^lla,,

B denotes a nitrogen atom or a group CR ^IIIa ,

• R "and R ¹ ", and; where appropriate, R ^11a and R ^11a , which are identical or different, each denote a hydrogen atom, or a linear or branched hydrocarbon-based chain, optionally cyclized in whole or in part, and optionally substituted, this chain preferably being: alkyl, alkenyl or alkynyl group, linear or branched optionally substituted, for example by at least one perfluoroalkyl group, the tert-butyl, isopropyl, propyl (nPr), butyl (nBu) and methyl groups being particularly preferred a linear or branched perfluoroalkyl group; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example with at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, in particular by at least one alkyl or alkoxy group.

10. Composition according to one of the preceding claims, characterized in that the carbene corresponds to the general formula (1-1 a) or (1-1 a ') below:

wherein: • R ¹ , R ", R" ^a , R '"and B are as defined in claim 7, and

• R ^ιv denotes a hydrocarbon chain, linear or branched, optionally cyclized in whole or in part, and optionally substituted, this chain preferably being: a linear or branched, optionally substituted alkyl, alkenyl or alkynyl group, for example by at least one group perfluoroalkyl, the tert-butyl, isopropyl, propyl (nPr), butyl (nBu) and methyl groups being particularly preferred a linear or branched perfluoroalkyl group; a cycloalkyl group, optionally substituted, for example by at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, in particular by at least one alkyl or alkoxy group;

Composition according to one of the preceding claims, characterized in that the carbene is a compound chosen from the following compounds:

Phosphino (amino) carbenes of formula (II):

bisphosphinocarbenes of formula (III)

(IV) (IV)

where each of the groups R, R _P , R _P ¹ , R _P ² , R _P ³ , R _P ⁴ , R _N , and R _P 1 represents, independently of the other groups, a hydrocarbon chain, linear or branched, optionally cyclized into all or part, and optionally substituted, this chain being preferably: a linear or branched, optionally substituted alkyl, alkenyl or alkynyl group, for example by at least one perfluoroalkyl group, a perfluoroalkyl group, linear or branched; a cycloalkyl group, optionally substituted, for example with at least one alkyl or alkoxy group; an aryl group optionally substituted, for example by at least one alkyl or alkoxy group; an alkylaryl or arylalkyl group, where the aryl part is optionally substituted, for example by at least one alkyl or alkoxy group, it being understood that, in each of the formulas (II), (III), (IV) and (IV), the group R and the group R ^p may optionally be bonded together to form a heterocycle with the two heteroatoms to which they are bonded and the divalent carbon [the heterocycle thus formed having, if appropriate, preferably from 5 to 7 members].

12. Composition according to one of the preceding claims, characterized in that the proportion of carbene is between 0.1 and 50% by weight relative to the weight of the composition, preferably between 1 and 30%.

13. Composition according to one of the preceding claims, characterized in that it is in the form of a solution, a liquid dispersion or a solid mixture

14. Process for preparing the composition according to one of claims 1 to 13 comprising a step of mixing the carbene (or a precursor) and the organic matrix or precursor

15. Process for the preparation of the composition according to one of claims 1 to 13 comprising a step of polymerization of an organic matrix precursor in the presence of carbene or a precursor

16. Use of the composition according to one of claims 1 to 13 as a catalyst for chemistry reactions.

17. Use of the composition according to claim 16, characterized in that the reaction is the polymerization of organosiloxanes, the cyanosilylation of aldehydes, the transesterification, the polymerization via the opening of rings such as lactides, lactones, caprolactones, cyclic anhydrides

18. Use of the carbene in the composition according to one of claims 1 to 13 as ligand of organometallic complexes

19. Use of an organic matrix or an organic matrix precursor as described in one of claims 1 to 13 for protecting a carbene, as described in one of claims 1 to 13, from water. (liquid and / or vapor) and / or oxygen