Catalysts for hydrosilylation reactions

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 1 CATALYSTS FOR HYDROSILYLATION REACTIONS The invention relates to a catalyst suitable for the catalysis of hydrosilylation reactions.

The addition of an organosilyl compound having an Si — H unit to an olefin or to an acetylene derivative by formation of a carbonilicon bond (hydrosilylation reaction) is conventionally carried out in the presence of a metal catalyst.

The hydrosilylation reaction is shown schematically as follows in the case of olefins ~~ IIH As an example of a catalyst, platinum catalysts have been recommended by many authors.

Thus, US 2,823,218 describes a chloroplatinic acid as a catalyst. US 2 970 150 proposes the use of metallic platinum on a finely divided support.

The hydrosilylation methods described in these patents are, however, unattractive from an economic point of view since they require the use of large amounts of platinum catalyst.

Thus, to date, most industrial hydrosilylation reactions are catalyzed by Karstedt's solution which consists of platinum complexes with oxidation degree 0.

The general formula of the Karstedt complex is Pt2 (tetramethyldivinylsiloxane) 3:

Mes, ~ Met ~ Me M; Me ~ Me ~ Si Si S ~ Si ~ Me \ / Me \ p ~ Pt ~ - 'I ~ Pt p M. ~ \ S.

Me Me Me where Me represents methyl.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 2 One of the drawbacks of this catalyst lies in a possible instability of the catalyst during the reaction: it was possible to observe the precipitation of metallic platinum and the formation of colloids insoluble in the reaction medium: this instability of the catalyst in the reaction medium has the effect of reducing the catalytic activity.

In addition, this results in turbid and strongly colored solutions, little appreciated by the user insofar as they lead to the formation of strongly colored hydrosilylation products.

Another major drawback of the Karstedt catalyst is the concomitant formation of by-products of the hydrosilylation reaction: alongside the hydrosilylation products are isolated the products resulting from reactions of isomerization of the olefinic double bond and / or reactions of olefinic double bond. hydrogenation.

One of the objectives of the present invention is therefore to provide a catalyst complex. stable, allowing side reactions to be limited.

Owing to its excellent stability, the complex of the invention also makes it possible to operate at higher reaction temperatures.

The other advantages of the invention will become apparent to those skilled in the art on reading the preferred embodiments of the invention.

The invention relates more specifically to a metal complex of formula I:

2o R 5 R6 Y ~ X ~ Ra ~ M ~ L \ Y R3 ./~ I 2 R 1 R2 in which M represents a metal in the oxidation state 0 chosen from the metals of group 8 of the periodic table such as published in Handbook of Chemistry and Physics, 65th edition, 1984-1985;

X represents O, NRa or CRfR9;

Y ~ and Y2 represent, independently of one another, CRbR ~ or SiRdRe;

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 3 R ~, R2, R5 and R6, identical or different, are chosen from a hydrogen atom, an alkyl group and an aryl group optionally substituted by alkyl ;

R3, R4, Ra, Rb, R ~ are independently selected from a hydrogen atom; an alkyl group; acyl; aryl optionally substituted by alkyl;

cycloalkyl optionally substituted by alkyl; and arylalkyl in which the aryl part is optionally substituted by alkyl;

Rd and Re are independently selected from alkenyl; alkynyl; alkyl;

alkoxy;

acyl; aryl optionally substituted by alkyl; cycloalkyl optionally substituted by alkyl; and arylalkyl in which the aryl part is optionally substituted by alkyl; or when Y ~ and Y2 independently represent SiRdRe, two Rd groups bonded to two distinct silicon atoms together form a chain of formula R n R 'in which n is an integer from 1 to 3; X is as defined above; R and R ', identical or different, take any of the meanings given above for Re, it being understood that, when n is 2 or 3, a single silicon atom of said chain may be substituted by one or two alkenyl groups or alkynyl;

or else when Y, and Y2 independently represent SiRdRe, two Rd groups bonded to distinct silicon atoms together form a saturated hydrocarbon chain, the two Rb groups together with said silicon atoms and X forming a 6 to 10 membered ring; or when Y ~ and Y2 independently represent CRbR ~, two Rb groups linked to distinct carbon atoms together form a saturated hydrocarbon chain, the two Rb groups together with the carbon atoms which carry them and X form a ring from 6 to 10 links;

Rf and R9 represent, independently of one another, a hydrogen atom; an alkyl group; acyl; aryl optionally substituted by alkyl;

cycloalkyl CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 4 optionally substituted by alkyl; arylalkyl in which the aryl part is optionally substituted by alkyl; a halogen atom; an alkenyl group; an alkynyl group; or a SiG ~ G2G3 group where G ~, G2 and G3 are independently of each other alkyl; alkoxy; aryl optionally substituted by alkyl or alkoxy; or arylalkyl in which the aryl part is optionally substituted by alkyl or alkoxy;

L represents a carbene of formula IL1 or IL2 T ~ ~ s T4 äiN T4 \ A ~ B ~ II.1 ~ C: II.2 / g ~ N / ~ ~ N / T3 ~ T2 T2 T ~ in which - A and B independently represent C or N, it being understood that when A represents N, then T4 represents nothing and when B represents N, then T3 represents nothing;

- T3 and T4 independently represent a hydrogen atom; an alkyl group; cycloalkyl optionally substituted by alkyl or alkoxy; aryl optionally substituted by alkyl or alkoxy; alkenyl; alkynyl; or arylalkyl in which the aryl part is optionally substituted by alkyl or alkoxy;

- T ~ and T2 independently represent an alkyl group; an alkyl group which is perfluorinated or optionally substituted with a perfluoroalkyl group;

cycloalkyl optionally substituted by alkyl or alkoxy; aryl optionally substituted by alkyl or alkoxy; alkenyl; alkynyl; or arylalkyl in which the aryl part is optionally substituted by alkyl or alkoxy; or else - the substituents T ~, T2, T3 and T4, can form two by two, when they are located on two adjacent vertices in the formulas IL1 and II.2, a saturated or unsaturated hydrocarbon chain.

According to the invention, the degree of oxidation 0 of the metal M is an essential characteristic of the invention.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 Preferably, the metals of group 8 which M represents are palladium, platinum or nickel.

According to a more preferred embodiment of the invention, M represents platinum in oxidation state 0.

By alkyl, one understands according to the invention a saturated hydrocarbon chain, linear or branched, preferably from 1 to 10 carbon atoms, for example from 1 to 8 carbon atoms, better still from 1 to 7 carbon atoms.

Examples of alkyl groups are especially methyl, ethyl, isopropyl, n-propyl, tert-butyl, isobutyl, n-butyl, n-pentyl, isoamyl and 1,1dimethylpropyl.

According to the invention, the alkyl part of the alkoxy radical is as defined above.

The perfluorinated alkyl radical or optionally substituted with a perfluoroalkyl group preferably has the formula ~ CH2) P ~ 9F29 + 1 in which p represents 0, 1, 2, 3 or 4; q is an integer of 1 to 10; and CqF2q + ~ is linear or branched.

Preferred examples of this radical are - (CHZ) 2 --- (CFz) 5-CF3 and - (CF2) ~ --CF3.

The expression aryl denotes an aromatic hydrocarbon group of 6 to 18 carbon atoms, monocyclic or polycyclic and preferably monocyclic or bicyclic. It should be understood that, in the context of the invention, by polycyclic aromatic radical is meant a radical having two or more aromatic rings, condensed with each other, that is to say having, two by two, at the minus two carbons in common. By way of example, mention may be made of the phenyl, naphthyl, anthryl and phenanthryl radicals.

The expression arylalkyl denotes an alkyl group as defined above, substituted by one or more aryl groups on its hydrocarbon chain, the aryl group being as defined above.

Examples are benzyl and triphenylmethyl.

By acyl is meant according to the invention, a Ro-CO- group where Ro represents alkyl as defined above; or else an Ar-CO- group where Ar represents an aryl group as defined above, or else arylalkyl in which aryl and alkyl are as defined above and in which the aryl part is optionally substituted by alkyl.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 6 By cycloalkyl is meant a saturated mono- or polycyclic hydrocarbon radical, preferably mono- or bicyclic, preferably having 3 to 10 carbon atoms, better still from 3 to 8.

The term “polycyclic saturated hydrocarbon radical” is understood to mean a radical having two or more cyclic rings attached to each other by α and / or / and condensed bonds in pairs.

Examples of polycyclic cycloalkyl groups are adamantane and norbornane.

Examples of monocyclic cycloalkyl groups are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl.

The term “alkenyl” is understood to mean an unsaturated, linear or branched hydrocarbon-based chain, having at least one olefinic double bond, and more preferably a single double bond.

Preferably, the alkenyl group has 2 to 8 carbon atoms, more preferably 2 to 6.

Preferred examples of alkenyl groups are vinyl and allyl groups.

By alkynyl is meant according to the invention, an unsaturated hydrocarbon chain, linear or branched, having at least one acetylene triple bond, and more preferably a single triple bond.

Preferably, the alkynyl group has 2 to 8 carbon atoms, more preferably 2 to 6 carbon atoms. By way of example, mention may be made of the acetylenyl group, as well as the propargyl group.

According to a preferred embodiment of the invention, Y ~ and Y2 represent either both CRbR ~ or both SiRdRe, such that the preferred compounds of the invention have either the formula L1 or the formula L2 R R5, 5 Rb R6 Rd ~ R6 Rc Re / i I.1 XR R3 ~ 2. 3 / ~ I.2 Rb ~ R1 Rd 12 R1 Rc Re R2 R2 where Rb 'and R ~' are the substituents Rb and R ~ of Y, in formula I.1;

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 7 Rb2 and R ~ 2 are the substituents Rb and R ~ of Y2 in the formula L2;

Rd 'and Re' are the Rd and Re substituents of Y ~ in the formula L1;

Rd2 and Re2 are the Rd and Re substituents of Y2 in the formula L2.

Thus, Rb 'can be the same or different from Rb2; R ~ 'may be the same or different from R ~ 2; Rd 'can be the same or different from Rd2; and Re 'can be the same or different from Re2.

Preferably, Rb '= Rb2; R ~ '= R ~ 2; Rd '= Rd2; and Re '= Re2.

Among the latter compounds, those for which R3 = R4; R5 = R2; and R, = R6, are still preferred.

According to another preferred variant of the invention, Rd 'and Rd2 together form RI (a) or an -X- (~~ -X) ~ chain in which n is an integer R' from 1 to 3; X is as defined above; and R and R ', identical or different, take any of the meanings given above for Re, it being understood that, when n is 2 or 3, a single silicon atom of said chain may be substituted by one or two alkenyl or alkynyl groups;

(b) or a saturated hydrocarbon chain, such that the two substituents Rd, together with the two silicon atoms which carry them and X, form a ring of 6 to 10 members, preferably of 6 to 8 members.

When Rd 'and Rd2 form the chain (a), it is preferred that n is 1 or 2 (better still n is 1) and that R = Re, the two Re groups carried by the two silicon atoms being identical.

In this case, Re preferably represents alkyl, for example methyl.

More preferably, in these compounds, R 'represents -CR3 = CR, R2 and R ~ = R6; R5 = Rz; and R3 = R4.

When Rd 'and Rd2 form chain (b), it is preferred that the two Rd groups, together with the two silicon atoms and the X group, form an 8-membered ring.

In this case, it is preferred that Re 'is identical to Re2.

These compounds have the general formula CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 8 R5 - 1 M ~ L R3 / 1 R1 R2 where T represents alkyl, i is an integer between 0 and 5, T being located on one or more of the vertices 1, 2, 3, 4 and 5 of the above formula.

In the same way, when Y1 and Y2 represent CRbR ~, the two Rb groups linked to distinct carbon atoms can together form a saturated hydrocarbon chain (c), such that the two Rb groups together with the carbons which carry them and X form a 6 to 10 membered ring.

Preferably, the ring formed is an 8-membered ring, in which case the metal complex corresponds to the formula R5 1 1 Rc R6 ~ CM ~ L ~ T ~ ia, C 5 R 2 I R1 c 2 where T represents alkyl; i is an integer between 0 and 5, T being located on one or more of the vertices 1, 2, 3, 4 and 5 of the above formula.

In the context of the invention, two Rd groups linked to two distinct silicon atoms can form a chain of formula CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 9 RI -X- (S iX) I n R 'When this is the case, it is preferred that X represents O in the compounds of the invention.

These preferred compounds have the general formula Rs R4 R3 R ~ R ~~ O \ \ R 5 SI R Si Re2 / 'OS iO ~ Re 1 ln R' Among these compounds, it is preferred that Re '= Re2.

Advantageously Re '_ Re2 represents alkyl (for example methyl).

Preferably, n is 1 or 2 and R = Re ', it being understood that when n is 2, a single silicon atom of the O- (SiRR'-O) ~ - chain can be substituted by one or two alkenyl groups or alkynyl.

More preferably, R '_ -CR3 = CR ~ R2 and R, = Rs; R2 = R5 and R3 = R4.

The expression "represents nothing" means that the substituents -T3, respectively -T4, are non-existent.

In fact, in formulas II.1 and IL2, the nitrogen atom is trivalent, such that when A or B represents N, the nitrogen atom cannot have an additional substituent.

According to a particular embodiment of the invention, the carbenes of formulas II.1 and IL2 have at least two condensed rings, that is to say that two substituents at least among T ~, T2, T3 and T4, located on two adjacent vertices, together form a saturated or unsaturated hydrocarbon chain, preferably having 3 to 6 carbon atoms.

By saturated or unsaturated hydrocarbon chain is meant a linear or branched hydrocarbon chain which may or may not have one or more unsaturations of the olefinic double bond or acetylenic triple bond type.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 When the carbenes IL1 and II.2 have two condensed rings, they therefore correspond to one of the following formulas, in which (aik) represents a saturated hydrocarbon chain or unsaturated 5 T ~ ~ 1 (alk) A'N 'A ~ N ~~ A ~ N II.1 I ~ yh Ç ~ (alk) II Ç:

(N 8 'alk T3 IN 10 () T2 T2 T3 (alk) ~ 3 4 2 ~ ~~ ~ ~ .-. A ~ B I. A' ~ C: j ~ C; (alk) ~ ~:

N ~ N 'T N'N ~ ~' N ~ (alk) 1 ~ 1 It should be understood, however, that the carbenes IL1 and II.2 may have more than two condensed nuclei.

When Rf and / or R9 represents SiG ~ G2G3, it is preferred that Rf and / or R9 is trialkylsilyl, for example SiG ~ G2G3 where G ~ = G2 = G3 = alkyl.

Subgroups of the metal complexes of the invention consist of the complexes for which - X = O; Y ~ and Y2 independently represent SiRdRe; or - X = NRa; Y1 and Y2 independently represent CRbR ~; or - X = NRa; Y ~ and Y2 independently represent SiRdRe; or - X = CRfRg; Y ~ and Y2 independently represent CRbR ~; or - X = CRfR9; Y ~ and YZ independently represent SiRdRe.

Among these metal complexes of formula I, preference is given to those for which - when X represents O, Y ~ and Y2 independently represent SiRdRe;

or CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 11 - when X represents NRa, Y ~ and Y2 independently represent CRbR ~; or - when X represents CRfR9, Y ~ and Y2 independently represent CRbR ~.

Most preferably, X represents O and Y, and Y2 independently represent SiRdRe in the metal complex of formula I.

In the context of the invention, the expression “independently represent” means that the designated substituents are either identical or different.

More preferably, R ~, R2, R5 and R6 are hydrogen atoms.

Preferred meanings of R3 and R4 are in particular a hydrogen atom; an alkyl group; aryl optionally substituted by alkyl;

and cycloalkyl optionally substituted by alkyl.

Among these preferred meanings, it is particularly advantageous that R3 and R4, which are identical, represent a hydrogen atom; (C3-C $) cycloalkyl or (C, -C $) alkyl.

More preferably, the diolefin ligand of the complex of formula I is symmetrical, that is to say that R5 = R2; R6 = R ~; R3 = R4 and the two groups Y ~, Y2 are either strictly identical to each other, or Y ~ = CRb 'R ~ and Y2 = CRb2R ~ where Rb' and Rb2 together form a symmetrical chain, or Y ~ = SiRd'Re and Y2 = SiRd2Re where Rd 'and Rd2 together form a symmetrical chain.

A preferred group of complexes according to the invention consists of complexes of formula I in which L represents a carbene of formula IL1.

Preferably, A and B in formulas IL1 and IL2 both represent a carbon atom.

Preferred meanings of T ~ and T2 are alkyl; cycloalkyl;

arylalkyl;

and aryl optionally substituted by alkyl.

Preferred meanings of T3 and T4 are hydrogen; alkyl;

cycloalkyl; arylalkyl; and aryl optionally substituted by alkyl.

Preferably, when T ~, T2, T3 or T4 represents alkyl, then alkyl is methyl, isopropyl or tert-butyl.

Likewise, when T ~, T2, T3 or T4 represents aryl, then aryl is phenyl.

When T ~, T2, T3 or T4 represents aryl optionally substituted by alkyl, then T ~, T2, T3 or T4 is tolyl or xylyl.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 12 When T ~, T2, T3 or T4 represents arylalkyl, then arylalkyl is preferably benzyl or triphenylmethyl.

When T ~, T2, T3 or T4 represents cycloalkyl, then cycloalkyl is preferably cyclopentyl, cyclohexyl or adamantyl.

A preferred group of complexes of formula I consists of complexes for which in the carbene of formulas II.1 or IL2, T3 and T4 represent a hydrogen atom.

Likewise, the complexes of formula I in which T ~ and T2 are chosen from (C, -C8) alkyl and (C3-C8) cycloalkyl form a preferred subgroup.

More preferably, T, and T2 are the same and represent (C3-C $) cycloalkyl.

Advantageously, T ~ and T2, identical or different, represent (C ~ C8) alkyl or (C3-C8) cycloalkyl; or else R3 and R4, identical or different, represent (C, -Ca) alkyl or (C3-C8) cycloalkyl; or even T ~, T2, R3 and R4, which are identical or different, represent (C, -C $) alkyl or (C3-C8) cycloalkyl.

A particularly preferred group of metal complexes of formula I consists of complexes of formula Rd T 2o Re gi R3 / NO Pt E --_: C \ R3 NR / ¿i T2 d Re in which R3 represents a hydrogen atom; a (C ~ -C $) alkyl group; or a (C3-C $) cycloalkyl group optionally substituted by (C ~ -C4) alkyl;

T ~ and T2 are identical and represent (C ~ -C8) alkyl or (C3-C8) cycloalkyl;

Rd and Re are as defined above.

Other preferred subgroups of the invention are defined as follows - Metal complexes of formula I in which Y ~ and Y2, which are identical, represent SiRdRe; R ~ = Rz = R3 = R4 = R5 = R6 = H; X = O; Rd and Ro are CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 13 independently selected from alkyl; aryl optionally substituted by alkyl;

alkenyl; and alkynyl.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = O; R1 = R6; R2 = R5; R3 = R4; R ~ and R2 independently represent alkyl; R3 represents alkyl or aryl optionally substituted by alkyl; Rd and Re independently represent alkyl; alkenyl; alkynyl; or aryl optionally substituted by alkyl.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = O; R, = R2 = R3 = R4 = R5 = R6 = H; and Rd = Re = methyl or else Rd = methyl and Re = phenyl.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = O; R, = R3 = R4 = R6 = H; R2 = R5 = alkyl.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = CRfRg; Rf = R9 = a hydrogen atom; Rd and Re, identical or different, are chosen from alkyl; and aryl optionally substituted by alkyl; R, = R6; R2 = R5; R3 = R4; R ~ and R2 are selected from a hydrogen atom and an alkyl group; R3 represents a hydrogen, alkyl or aryl atom optionally substituted by alkyl.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = CRfR9 where Rf and R9 represent a halogen atom, preferably a chlorine atom or a bromine atom; Rd = Re = alkyl, preferably methyl; R ~ = R2 = R3 = R4 = R5 = R6 = H.

- Metal complexes of formula I in which Y ~ and Y2, identical, represent SiRdRe; X = CRfR9 where Rf and Rg represent SiG ~ G2G3 such as trialkylsilyl (for example Si (CH3) 3); Rd = Re = alkyl, preferably methyl; R ~ = R2 = R3 = R4 = R5 = R6 = H.

- Metal complexes of formula I in which X represents -NRa;

Y ~ and Y2 identical represent SiRdRe; R ~ = R6; R2 = R5; R3 = R4.

- Metal complexes of formula I in which X represents NRa; Y ~ = YZ = SiRdRe; the two Rd groups together form the chain -NRa- (SiReRd ° -NRa) ~ _ in which Rd ° represents -CR3 = CR ~ R2; n represents from 1 to 3; R ~ _ R6; R2 = RS; andR3 = R4.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 14 The complexes of the invention are prepared in a conventional manner, for example from complexes known from the state of the art by ligand exchange, c ' that is to say by adding the appropriate carbene of formula II.1 or IL2 to a metal complex of the metal M, in solution, designated precursor complex.

Suitable precursor complexes are the Karstedt complex of formula - Pt2 [ViMe2Si-O-SiMe2Vi] 3 in which Vi represents the vinyl radical; and more generally M2 [RSR6C = CR4-Y ~ -X-Y2-CR3 = CR ~ R2] 3 where M, R5, R6, R4, R3, R ~, R2, Y ~, X and Y2 are as defined herein above, such as for example M2 [CRSR6 = CR4-SiRdRe-O-SiRdRe-CR3 = CR ~ RZ] 3 it being understood that M, Ri, R2, R3, R4, R5, R6, Rd and Re are as defined above;

- Pt (COD) 2 in which COD represents cyclooctadiene and more generally M (COD) 2 where M is a group 8 metal; or else metal complexes of olefin and bisphosphine.

The complexes of formula I are generally prepared from precursor complexes having, as ligand, at least one diolefinic compound of formula III R6 Y 1 R4 III R3 Y2 R1 R2 in which R ~, R2, R3, R4, R5, R6, X, Y ~ and Y2 are as defined above for formula I.

These ligands are either commercially available or readily prepared by those skilled in the art from commercial compounds.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 When X represents NRa and Y ~ and Y2, independently of one another, represent CRbR ~, the compounds of formula III are amines which is easy to prepare by carrying out conventional methods of organic chemistry.

Thus, when Ra is distinct from a hydrogen atom, these amines can be easily prepared from the corresponding primary amine of formula RaNH2 by the action of suitable chlorides preferably in the presence of an organic or inorganic base.

When the diolefin III is symmetrical (i.e., R4 = R3; R5 = R2;

R, = R6; and Y, = Y2), RaNH2 is reacted with two equivalents of a chloride of formula CI-CRbR ~ -CR3 = CR1R2 (IV) in the presence of a base.

When the diolefin III is disymmetric, it is preferable to protect the amino group of RaNH2 with an appropriate conventional protecting group P before reacting the resulting compound of formula RaNHP with the chloride of formula V CI-CRb2R ~ 2-CR3 = CR ~ R2 (V) in the presence of a suitable base.

Then, after deprotection, the resulting amine is reacted with a chloride of formula CI-CRb 'R ~' -CR4 = CR5R6 (VI) so as to obtain the expected amine.

In formulas IV, V and VI above, the substituents R ~, R2, R3, R4, R5 and R6 are as defined for formula I; Rb 'and Rb2 are as defined for Rb;

and R ~ 'and RAZ are as defined for R ~.

The protective groups P of the amine functions as well as the corresponding deprotection methods are described in Protective Groups in Organic Synthesis, Greene TW and Wuts PGM, ed.

John Wiley and Sons, 1991, and in Protecting Groups, Kocienski PJ, 1994, Georg Thieme Verlag.

When Ra represents a hydrogen atom, it is desirable to select, as starting compound, the amine of the following formula VII, previously protected at the level of the amino function by a protective group P as defined above CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 16 NH2-CRb2 RAZ-CR3 = CR ~ R2 (VII).

The protected amine VII is reacted with a chloride of formula VI as defined above, preferably in the presence of a base, then by deprotection of the amino function, the expected compound of formula III is isolated.

Suitable bases are for example an organic base chosen from triethylamine, diisopropylamine, pyridine and N, N-dimethylaniline or an inorganic base such as NaOH, KOH, NaHCO3, Na2CO3, KHC03 and K2CO3.

When X represents O and Y represents CRbR °, the compounds of formula III are ethers.

These ethers are commercially available or prepared in a manner known per se from commercially available compounds.

The compounds of formula III in which X represents CRfR9 and Y represents CRbR ~ are diolefins easily accessible to those skilled in the art by synthesis or available commercially.

The compounds of formula III in which X represents NRa where Ra represents H or alkyl; R, = R6; R2 = R5; R3 = R4; and Y, = Y2 = SiRdRe can be prepared by the action of an amine Ra-NH2 with two equivalents of a silyl chloride of formula CISiRdRe-CR3 = CRI R2 in which Re, Rd, R ~, R2 and R3 are such as defined above.

The compounds of formula III in which X represents NRa, Ra being as defined above in formula I; Y ~ = Y2 = SiRdRe where Re is as defined above in formula I; the two Rd groups together form the chain -NRa- (SiReRd ° -NRa) n in which Ra and Re are as defined above; n represents an integer of 1 to 3; Rd ° represents -CR3 = CR, R2; R ~ = R6; R2 = R5 and R3 = R4, can be prepared by reacting the amine Ra-NHZ with silyl chloride of formula Cl2SiRe-CR3 = CR ~ R2 in which Re, R ~, R2 and R3 are as defined above. above.

The compounds of formula III in which X represents O, and Y ~ and Y2 represent SiRdRe are linear, branched or cyclic siloxanes which are marketed or the preparation of which is possible from commercial compounds, by carrying out the conventional methods of state of the technical CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 17.

Examples of preferred formula III siloxanes are ViMe2SiOSiMe2Vi and (MeViSiO) 3, the second formula representing a cyclosiloxane in which Vi is vinyl.

In the case of symmetrical compounds of formula III, that is to say those for which R i = R6; R2 = R5; R3 = R4 and Y ~ = Y2, one of the following synthesis variants can be implemented.

(Variant a): For the preparation of said symmetrical siloxanes of formula III for which R ~, R2, R3, Rd and Re are independently chosen from alkyl, aryl, alkenyl and alkynyl, it is possible to react a silyl chloride of formula Cl2SiRdRe with an organometallic compound of formula CRI R2 = CR3-Mg-Hal where R ~, R2, R3 are as defined above and hal represents a halogen atom under the usual reaction conditions involving magnesians.

(Variant b): For the preparation of said symmetrical siloxanes of formula III for which R ~ = R2 = R3 = H and R ~, Rd are chosen from alkenyl, alkynyl, aryl and alkyl, it is possible to react a silyl chloride of formula Cl2SiRd-CH = CHZ with an organometallic compound of formula Re-Mg-hal in which Re is as defined above and hal represents halogen.

For the implementation of this variant, those skilled in the art may refer to J.

Gen.

Chem., USSR, 1977, 47, 1402-1406.

(Variant c): For the preparation of said symmetrical siloxanes of formula III in which R ~ = R3 = H and R2 represents alkyl, a siloxane of formula H-SiRdRe-O-SiRdReH can be reacted with two equivalents of an acetylenic hydrocarbon of formula H C --- C-R2 in which RZ is as defined above.

Cyclic siloxanes of formula III are described in US 4,593,084.

The compounds of formula III in which X represents CRfR9 and Y, and Y2 independently represent -SiRdRe can be prepared by carrying out a process analogous to one of those described in CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 18 - J. of Organometallic Chemistry, 1996, vol. 521, 99-107 (which process is more particularly suitable for the preparation of symmetrical compounds of formula III in which Y ~ = YZ; Rf = R9 = H; Rd, Re represent alkyl or aryl optionally substituted by alkyl; R3 represents an atom hydrogen;

alkyl; or optionally substituted aryl; and R ~, R2 are selected from a hydrogen atom and alkyl);

- J. of Organometallic Chemistry, 1997, vol. 545-546, 185-189 (which process is more particularly suitable for the preparation of symmetrical compounds of formula III in which Y, = Y2; Rf = Rg = CI or Br; Rd and Re represent alkyl; R ~ = RZ = R3 = a hydrogen atom);

- J.

Chem.

Soc., Perkin Trans II, 1987, p. 381 (which process is more particularly suitable for the preparation of symmetrical compounds of formula III in which Y ~ = Y2; Rf = R9 = SiG ~ G2Gs; Rd and Re represent alkyl; R ~ _ R2 = R3 = a hydrogen atom ).

The carbenes of formulas II.1 and II.2 can be prepared by deprotonation of imidazolium salts, tetrazolium salts, triazolium salts, or pyrazolium salts as appropriate, under the action of a base.

These reactions can be schematized as follows T ~ T4 / T4v iN 'A ~ N \ 2o AC bai ~~ C:

T ~~ N / XT / BaN / 3 3 1 T2 VIII.I II.I ~ 3 T ~ 3 T4v / B 4 \, ~~ BC ba ~ ~ C:

T 'N / X _ / NON / 2 ~ T2 1 T ~ T1 VIII.2 II.2 CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 19 In these reaction schemes, T ~, T2, T3 , T4, A and B are as defined above for formula I and X - represents an anion.

The nature of the anion X - is not critical according to the invention. The anion X - is the anion derived from an organic or inorganic Brénsted acid (protic acid).

Usually the X - anion is derived from an acid with a pKa less than 6.

Preferably, X - is derived from an acid with a pKa less than 4, more preferably less than 2.

The pKas referred to here are the pKas of acids as measured in water.

Examples of acids are the carboxylic acids of formula GoCOOH in which Go represents alkyl, and for example (C, -C22) alkyl; or else aryl, and for example (C6-C ~ 8) aryl optionally substituted with one or more alkyl, preferably one or more (C ~ -C6) alkyl; sulfonic acids of formula Go-SO3H in which Go is as defined above; and phosphonic acids of formula Go-P03H in which Go is as defined above;

other acids are HF, HCl, HBr, HI, H2S04, H3PO4 and HC104.

Preferred examples of carboxylic acids are acetic acid, benzoic acid, and stearic acid. As preferred sulfonic acid, there will be mentioned benzene sulfonic acid and as preferred phosphonic acid, there will be mentioned phenylphosphonic acid.

According to the invention, the X - anions derived from HF, HCl, HBr, HI, H2SO4 and H3PO4 acids are more particularly preferred.

Thus, particularly preferred X - anions, according to the invention, are the halide, sulphate, hydrogen sulphate, phosphate, hydrogen phosphate and dihydrogen phosphate anions.

Mention may also be made, as anion, of tetrafluoroborates and hexaphenylphosphate.

The bases which can be used for the deprotonation of the salts of formulas VIIL1 and VIIL2 are strong bases chosen from alkali metal hydrides, alkali metal hydroxides, alkali metal carboxylates, alkali metal alcoholates and alkali metal amides.

Examples of a suitable base are therefore sodium hydride, potassium hydroxide, sodium methoxide, potassium tert-butoxide, lithium düsopropylamide and mixtures thereof.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 The deprotonation reaction is preferably carried out in a solvent capable of dissolving the starting salt of formula VIII.1 or VIII.2, as well as the other reagents.

The nature of the solvent also depends on the strength of the base.

Indeed, in the case of a strong base and particularly reactive starting salts, it may be necessary to operate at low temperature.

Generally, the reaction temperature is between 40 ° C and 78 ° C, preferably between 30 and -50 ° C, more preferably between 25 and -40 ° C, for example between 20 and -30 ° C.

10 Solvents which can be used in the process for preparing the carbenes are ethers, whether cyclic or not, such as diethyl ether, düsopropyl ether, tetrahydrofuran, dioxane, dimethoxyethane or dimethyl ether of diethylene glycol.

Other suitable solvents are dimethylsulfoxide, dimethylformamide, dimethylacetamide, hexamethylphosphorylamide [(CH3) 2N] 3P0 and hexamethylphosphoramide [(CH3) 2N] 3P.

The carbenes of formula II.1 in which A and B both represent a carbon atom can also be prepared by reduction of the corresponding thiones of formula IX 2o T ~ ~ T ~ T4wAi Ivi T4wA ~ N ~ CS ~ ~ C:

OT ~~ T ~ T 2 2 IX This reaction was described by N.

Kuhn in Synthesis, 1993, 561.

Preferably, the reduction is carried out in a solvent of the ether or amide type, as defined above, at a temperature of between 50 and 150 ° C., in the presence of potassium.

The starting salts of formula VIII.1 and VIIL2 can for their part be prepared by reaction of the corresponding imidazoles, pyrazoles, triazoles and tetrazoles with an appropriate acid.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 21 The nature of the anion X 'in the salts of formulas VIII.1 and VIII.2 depends on the acid used in this step.

The acids which can be used are, for example, those listed above and from which X - is derived.

Another method of synthesizing salts of formula VIIL1 in which A = B = C is described in US 5,077,414.

This process comprises the reaction of an α-dicarbonyl compound X of the formula C -C -T3 X in which T3 and T4 are as defined above with HCHO and two amines of the formulas T, -NH2 and T2-NH2 in the presence of a suitable acid.

Other methods of preparing the salts of formula VIII.1 and VIIL2 are proposed in Chem.

Eur. J. 1996, 2, No. 12, pages 1627-1636 and Angew.

Chem.

Int.

Ed.

Engl. 1997, 36, 2162-2187.

Compounds of formula IX can be prepared by condensation of a suitable thiourea of ​​formula XI ST ~ HN ~ -NHT2 with an α-hydroxyketone of formula XII HO O ~ CH_C ~ T ~ 'T4 in which T ,, T2, T3 and T4 are as defined above.

Appropriate operating conditions are described in particular by N.

Kuhn in Synthesis, 1993, 561.

According to a particularly preferred embodiment of the invention, the metal complex of the invention has the formula CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 22 H Me H Me-Si H p Pte LHM eS i H Me H where L is as defined above.

A simple method of preparing this complex consists in reacting the carbene L with the Karstedt catalyst of average formula Pt2 [ViMe2Si-O SiMe2Vi] 3 in which Vi represents the vinyl radical.

This reaction can be carried out in bulk or in a solvent.

Examples of suitable solvents are ethers, cyclic or not, such as diethyl ether, düsopropyl ether, tetrahydrofuran, dioxane, dimethoxyethane or dimethyl ether of diethylene glycol; amides such as dimethylformamide or dimethylacetamide; aromatic hydrocarbons (such as toluene, xylenes and more particularly toluene);

and aliphatic alcohols of the (C, -C4) alkanol type (such as ethanol or isopropanol).

Advantageously, the reaction is carried out in an ether, and preferably in tetrahydrofuran.

The reaction temperature usually varies between 10 and 50 ° C, preferably between 15 and 35 ° C, most preferably between 20 and 25 ° C.

It is desirable to operate in the presence of a slight excess of carbene relative to the platinum.

Thus, the molar ratio of carbene L to platinum generally varies between 1 and 1.3, preferably between 1 and 1.1.

A simple way of proceeding consists in pouring, at the appropriate temperature, a solution of the carbene in a solvent, in a reactor containing a solution of the Karstedt catalyst in this same solvent.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 23 The molarity of the solutions of the carbene and of the catalyst is not critical according to the invention.

According to another of its aspects, the invention relates to a catalytic composition comprising, as active material, one or more metal complexes according to the invention.

The complexes of formula I of the invention can be used as a catalyst for hydrosilylation reactions.

The catalysts of the invention allow homogeneous catalysis of the reaction.

By hydrosilylation reaction is meant according to the invention the reaction of a compound having an ethylenic double bond or a triple acetylene bond (unsaturated compound) with a compound having at least one unit, s ~ -H, so as to form a C-Si bond.

The hydrosilylation reaction can be schematized as follows, in the case of a compound with an ethylenic double bond CC / '~' \ Si-H ~ CC \ ~ Si H and, in the case of a compound with an acetylenic triple bond -CC + -Si-H ~ ~ C = C ~ S ~ \ H / I \ Compounds with an ethylenic double bond may contain one or more double bonds and from 2 to 40 carbon atoms.

These compounds may be aliphatic hydrocarbons with a linear or branched hydrocarbon chain, or else cyclic hydrocarbons, said cyclic or aliphatic hydrocarbons optionally carrying one or more substituents of (C6C ~ $) aryl type optionally substituted by (C ~ -C6) alkyl.

Double bonds are generally terminal.

Preferably, the compound having an ethylenic double bond has a single double bond.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 24 Examples of olefins are ethylene, propylene, 1-butylene, 1pentene, 2-methylbutene-1, 1-hexene, 1-heptene, 1-octene, 3ethylhexene-1, 1-decene, 4,4-dimethylnonene-1, vinylcyclohexene, styrene and 2-vinylnaphthalene.

Acetylenic triple bond compounds can have one or more triple bonds and from 2 to 40 carbon atoms.

These compounds are generally aliphatic hydrocarbons with a linear or branched hydrocarbon chain, optionally substituted by (C3-C ~ o) cycloalkyl (which cycloalkyl may optionally bear one or more (C ~ -C6) alkyl) or / and by (C6C ~ o) aryl (which aryl can optionally carry one or more (C ~ -C6) alkyl).

Preferably, the acetylene triple bond compounds have a single triple bond.

Triple bonds are generally terminal.

Examples are ethynyl, 2-propynyl, 1-propynyl and 2-penten-4-ynyl.

The hydrosilylation of compounds comprising both one or more ethylenic double bonds and one or more acetylenic triple bonds can also be envisaged within the framework of the invention.

Under the operating conditions normally prescribed in the literature for hydrosilylation reactions, the formation of two types of hydrosilylation reaction by-products is observed, namely the isomerization products and the hydrogenation products.

Isomerization products result from the isomerization of double bonds.

Hydrogenation products result from the hydrogenation of double and triple bonds.

Surprisingly, when the hydrosilylation is carried out using the metal complexes of the invention as a catalyst, the formation of these by-products is greatly limited.

More particularly, there is a strong reduction in the rate of isomers formed.

The hydrosilylation reaction can be carried out in a solvent or in the absence of a solvent.

As a variant, one of the reagents can act as a solvent, for example the compound with an ethylenic double bond or with an acetylenic triple bond.

Suitable solvents are solvents miscible with the Si-H unit compound.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 Under the conditions of the hydrosilylation reaction, the catalyst complex of the invention must be dissolved in the reaction medium.

According to a preferred embodiment of the invention, the reaction medium for the reaction for preparing the catalyst complex is used as it is or after dilution, without intermediate isolation.

The compound with Si-H unit can be a silicon hydride of formula XIII aS iX 3_a ~ IIH in which X is a radical comprising a heteroatom such as O, Si, a halogen atom or the carbon atom of a aliphatic or aromatic group;

R is a hydrogen atom, an alkyl group, an aryl group, a cycloalkyl group, an alkoxy group, an aryloxy group or a cycloalkoxy group;

a is an integer from 0 to 3.

It should be understood that, according to the invention, the aliphatic, aromatic, alkyl, aryl, cycloalkyl, alkoxy, aryloxy, cycloalkoxy groups may or may not be substituted.

The nature of the substituents is defined so as not to give rise to side reactions during the hydrosilylation reaction.

Suitable examples of the silane are HSi (OC2H5) 3 and HSi (C2H5) 3.

The compound with Si-H unit can be a siloxane of formula XIV P3 H P4 ~ Si-O-Si ~ P ~ XIV P in which P ~ to P5 are independently chosen from alkyl, aryl, alkoxy, aryloxy, arylalkyl or arylalkoxy optionally substituted, P3, P4 and / or P5 may also represent a hydrogen atom.

Preferably, P ~ to P5 are independently selected from a (C ~ C22) alkyl group, preferably (C ~ -C ~ o) alkyl; a (C6-C ~ o) aryl group optionally substituted by one or more (C ~ -C ~ o) alkyl and / or (C ~ -C ~ o) alkoxy; an alkoxy group (C, CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 26 C22), preferably (C ~ -C ~ o) alkoxy; (C6-C ~ o) aryloxy in which the aryl part is optionally substituted by (C ~ -C6) alkyl and / or (C ~ -C6) alkoxy;

(C6C ~ o) aryl- (C ~ -C ~ o) alkyl in which the aryl part is optionally substituted by (C ~ -C6) alkyl and / or (C ~ -C6) alkoxy; or else (C6-C ~ o) aryl (C ~ -C, o) alkoxy in which the aryl part is optionally substituted by (C ~ -C6) alkyl and / or (C ~ C6) alkoxy.

The compound containing Si — H unit can be a polymer of polyhydrogenosiloxane type. Other suitable polymers and copolymers are polyhydrosilanes comprising a large number of repeating units containing Si — H bonds.

Preferably, the polymers which can be used have repeating units of formula HI -XS i I Ro in which X is a radical comprising a heteroatom such as O, Si or the carbon atom of an aliphatic or aromatic group; and Ro is a hydrogen atom or an organic group selected from alkyl, aryl, cycloalkyl, alkoxy, aryloxy or cycloalkoxy. As examples, there may be mentioned the polyhydrosiloxanes of formula R ~ R 1 ~ '' 11 i ~ 8 ¿~ ~ i ~ ~~ ~ ~ R12 R9 H n R13 in which R ~ to R ~ 3 are independently an atom hydrogen or an organic group.

Preferably, R ~, R8, R9, Rio, R ~~, R ~ 2 and R ~~ are chosen from a hydrogen atom, an alkyl, aryl, cycloalkyl, alkoxy, aryloxy and cycloalkoxy group;

n is an integer at least equal to 1 and preferably at least equal to 10 and, better still, between 10 and 100.

Appropriate polymers are polymethylhydrogenosiloxane, polydimethylsiloxane containing a -SiH group, methylhydro copolymers CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 27 genodimethylsiloxane, methylhydrogenomethyloctylsiloxane copolymers, and methylhydrogenomethyloctylsiloxane polymers, and methylhydro-methyloxiloxilocyloxane polymers.

In general, the polymers usable in the reaction have an average molecular weight of 300 or more and preferably between 300 and 10,000 (g / mol).

Examples of silicon hydrides are described in US 5,359,113.

Examples of solvents which can be used for hydrosilylation are in particular aliphatic hydrocarbons (such as pentane, hexane, heptane, pentamethylheptane or petroleum distillation fractions); aromatic hydrocarbons (such as benzene, toluene and xylenes: ortho-xylene para xylene and meta-xylene); halogenated aliphatic or aromatic hydrocarbons (such as tetrachlorethylene); or ethers (such as tetrahydrofuran or dioxane).

The hydrosilylation reaction can be carried out at a temperature between 15 ° C and 300 ° C, for example between 20 and 240 ° C, better still between 70 and 200 ° C, in particular between 50 and 140 ° C, very preferably between 50 and 100 ° C.

The relative amount of unsaturated compound and compound containing Si-H unit can be controlled so as to ensure the reaction of all unsaturations with Si-H bonds.

It is nevertheless preferable to operate in the presence of a molar excess of unsaturation.

Generally, the molar ratio of unsaturations to Si-H bonds varies between 1: 100 and 10: 1.

The concentration of unsaturated compound in the reaction medium is between 2 and 50% by weight.

According to the invention, the hydrosilylation reaction is carried out in the presence of a catalytic amount of one or more complexes according to the invention.

By catalytic amount is meant less than one molar equivalent of platinum relative to the amount of unsaturations present in the reaction medium.

In general, it suffices to introduce into the reaction medium less than 1000 ppm, preferably less than 100 ppm, better still less than 50 ppm of platinum calculated relative to the total mass of the unsaturated compound and of the compound containing Si — H units. .

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 28 According to a preferred embodiment of the invention, the unsaturated compound, the catalyst and the solvent are placed, with stirring, in a reactor.

The whole is brought to the desired temperature and the compound with a motif, s ~ -H is introduced with stirring. The invention is illustrated below in the light of the following examples.

EXAMPLE 1 1 - Preparation of the carbene of formula i 6H11 N: CNI C6H11 (cf.

Chem.

Eur. J. 1996, 2, 1627).

For this reaction, all the glassware used is dried in an oven at 150 ° C. overnight and then cooled under argon.

The THF is distilled over sodium / benzophenone just before use.

A 100 ml knit is loaded with 2.70 g (10 mmol) of 1,3dicyclohexylimidazolinium chloride then purged with a stream of argon before being suspended in 20 ml of THF.

About 50 ml of ammonia are then condensed at 78 ° C. in the knitting causing partial dissolution of the salt.

The acetone / dry ice bath is removed and 270 mg of 95% NaH (10.7 mmol - 1.07 eq.) Are added slowly using a solid-state funnel.

Each addition of NaH is followed by a significant evolution of gas (H2) and the salt in suspension gradually dissolves.

The reaction mixture is stirred for 1 hour 30 minutes at reflux of the solvent. The ammonia is then evaporated off and a pale yellow solution is obtained as well as a solid in suspension (NaCl).

This solution, the carbene concentration of which is 0.5M in THF, is used immediately for the preparation of the complexes.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 29 2 - Preparation of the platinum complex of formula CH3 \ ​​ÇH3 S i ~ N p Pt ~: C \ N CH ~ A Karstedt solution of 10 is prepared. % by weight of platinum (i.e. 1.52 mmol of platinum) according to the procedure described in US Pat. No. 3,775,452.

To 3 g of this solution, kept under stirring and diluted in 10 ml of tetrahydrofuran, is added dropwise using a dropping funnel, 3.2 ml of a 0.5 M solution of the carbene of formula i 6H11 N ~ C ~ NI C6H11 in tetrahydrofuran. The addition is complete after 10 minutes.

The reaction mixture is then stirred for 50 minutes at room temperature.

If necessary, the light insoluble matter is filtered off and the reaction mixture is concentrated in vacuo.

After concentration, a slightly yellow viscous residue is obtained.

In a few hours, an abundant white solid precipitates in the residual divinyltetramethyldisiloxane.

This is filtered, washed with a few milliliters of hexamethyldisilazane, then with pentane.

In this way 570 mg (yield 60%) of an analytically pure white powder is obtained.

CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 A fraction of this powder is recrystallized from a dichloromethane / absolute ethanol mixture.

The resulting crystals are analyzed by X-ray diffraction. The analysis confirms the structure of the complex obtained.

5 EXAMPLE 2 1 -Preparation of the carbene of formula CH3: CC H3 This carbene is prepared by carrying out the procedure illustrated in Example 1, paragraph 1, except that the 2.7 g (10 mmol) of chloride of 1, 3dicyclohexylimidazolinium are replaced by 2.3 g (10 mmol) of 1,3dimethylimidazolinium iodide.

2 - Preparation of the platinum complex of formula C H3 \ Ç ~ CH Si I 3 N 0 Pt E ---: Ç NI CH3 CH3 CH3 CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 31 This complex is prepared by carrying out the procedure of Example 1, other than that the carbene used as starting product has the formula:

~ Hs N: CNI CH3 After concentration, a yellow paste is obtained.

This is filtered, washed thoroughly with hot pentane.

An off-white solid is isolated (yield 35%), which is recrystallized from ethanol.

The resulting crystals are analyzed by X-ray diffraction. The analysis confirms the structure of the complex obtained.

EXAMPLE 3 Hydrosilylation of oct-1-ene by the action of (CH3) 3Si-O-Si (CH3) (H) OSi (CH3) 3 In a 250 ml knitted reactor equipped with a condenser, with magnetic stirring, with a thermometric sheath and heated by an oil bath, 5 g (45 mmol) of oct-1-ene, 10 g (1 equivalent of SiH units relative to the oct1 ene) of (CH3) 3SIO are placed -SI (CH3) (H) -OSI (CH3) 3.5 g of dodecane (used as an internal standard for analysis by gas chromatography), and orthoxylene in a sufficient quantity so as to ensure a concentration of 0.5M in silyl reagent and in oct-1-ene. The whole is brought to 70 ° C. and kept under stirring.

Then, a solution of the catalyst in dichloromethane containing 30 ppm of platinum calculated with respect to the total quantity of silyl derivative and of oct-1-ene is added to the preceding mixture, all at once.

The progress of the reaction is followed by gas chromatography (GPC).

The successive samples analyzed by GC are eluted beforehand on an activated carbon column.

The above hydrosilylation reaction is carried out under the same conditions using three different catalysts CA 02393629 2002-06-06 WO 01/42258 PCT / FR00 / 03362 32 - the Karstedt catalyst prepared according to US Pat. No. 3,775,452;

- the catalyst prepared in Example 1;

- the catalyst prepared in Example 2.

The results obtained expressed as degree of conversion (~) of SiH bonds in the silylated derivative and as percentage of isomerization (p) are reported in the following table.

TABLE Catalyst ~ (%) p (%) Karstedt 80 17 example 1 82 4.5 example 2 85 3.7 It is observed that the catalysts of the invention lead to much lower isomerization percentages (by a factor of 3) .

EXAMPLE 4 In this example, the hydrosilylation of 1-octene is carried out by the action of (CH3) 3SIO-SI (H) (CH3) -OSI (CH3) 3 in the presence of the complex of Example 2 as catalyst.

The amounts of reagents and of catalyst brought into contact are the same as in Example 3.

Only the way of proceeding has been changed.

In a 100 ml knitting equipped with magnetic stirring, a condenser and heated by an oil bath, 5 g (45 mmol) of oct-1-ene, 5 g of dodecane and the catalyst solution are placed. in dichloromethane (which contains 30 ppm of platinum calculated relative to the total amount of silyl derivative and oct-1ene).

This solution is kept under stirring and brought to 70 ° C.

Then 10 g (1 equivalent of Si-H units relative to oct-1-ene) of (CH3) 3Si0-Si (CH3) (H) OSi (CH3) 3 are introduced dropwise into the reaction medium.

The progress of the reaction is followed by gas chromatography.

A degree of conversion of Si — H bonds in the silylated derivative of 96% and a percentage of isomerization of 1.5% is obtained.