SYNTHESIS OF MONOMERIC, OLIGOMERIC AND POLYMERIC SIGMA-ACETYLIDE COMPLEXES OF PLATINUM, PALLADIUM, NICKEL AND RHODIUM

Reaction of equimolar quantities of Me3SnC = CRC = CSnMe3 [R = p-C6H4; p-C6H2(CH3)2; p-C6H4-p-C6H4] with the group 10 metal dihalide complexes, [M(XnBu3)2Cl2] (M = Pt, Pd, Ni; X = P, As; Bu = butyl) affords the polymeric species trans-[-M(XnBu3)2(-C = CRC = C -)]n in excellent yields. By varying the stoichiometry of these reactions, complexes of the type trans-[M(XnBu3)2(-C = CRC = CSnMe3)2] and trans-[ClM(XnBu3)2 C = CRC = CM(XnBu3)2Cl], which are precursors to higher oligomers, can be prepared. Treatment of the former with an excess of trans-[M(XnBu3)2Cl2] affords the trimetallic compound trans-[ClM(XnBu3)2(-C = CRC = C-)M(XnBu3)2(-C = CRC = C-)M(XnBu3)2-Cl], while reaction of the latter with two equivalents of Me3SnC = CRC = CSnMe3 followed by two equivalents of trans-[M(XnBu3)2Cl2] gives the complex trans-[ClM(XnBu3)2(-C = CRC = C-)M-(XnBu3)2(-C = CRC = C-)M(XnBu3)2(-C = CRC = C-)M(XnBu3)2Cl]. Treatment of the complex [Rh(PPh3)3Cl] (Ph = Phenyl) with one equivalent of Me3SnC = CRC = CSnMe3 [R = p-C6H4-p-C6H4] gives the polymeric species [-Rh(PPh3)2(SnMe3)(-C = CRC = C-)]n. Model compounds for other rhodium-containing sigma-acetylide complexes have been obtained from the reaction between the complex [Rh(PMe3)4Cl] (Me = CH3) and Me3SnC = CC6H5, which yields the compound mer,trans-[Rh(PMe3)3-(SnMe3)(-C = CC6H5)2] via the intermediate [Rh(PMe3)4(-C = CC6H5)]. Reaction of [Rh(PMe3)4Cl] with one equivalent of Me3SnC = CRC = CSnMe3 [R = p-C6H4-p-C6H4] yields the polymer mer,trans-[-Rh(PMe3)3(SnMe3)(-C = CRC = C-)]n.