Synthesis of monomeric, oligomeric and polymeric σ-acetylide complexes of platinum, palladium, nickel and rhodium

Reaction of equimolar quantities of Me₃SnCCRCCSnMe₃ [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(-CCRCC-)]_n in excellent yields. By varying the stoichiometry of these reactions, complexes of the type trans-[M(XⁿBU₃)₂(-CCRCCSnMe₃)₂] and trans-[ClM(XⁿBU₃)₂CCRCCM(Xⁿ BU₃)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(-CCRCC-)M(XⁿBU₃)₂(-CCRCC-)M(XⁿBU₃)₂Cl], while reaction of the latter with two equivalents of Me₃SnCCRCCSnMe3 followed by two equivalents of trans-[M(XⁿBu₃)₂Cl₂] gives the complex trans-[ClM(XⁿBU₃)₂(-CCRCC-)M(XⁿBu₃)₂(-CCRCC-)M(XⁿBu₃)₂(-CCRCC-)M(XⁿBu₃)₂Cl]. Treatment of the complex [Rh(PPhl)₃Cl] (Ph = Phenyl) with one equivalent of Me₃SnCCRCCSnMe₃ [R = p-C₆H₄-p-C₆H₄] gives the polymeric species [-Rh(PPh₃)₂(SnMe₃)(-CCRCC-)]_n. Model compounds for other rhodium-containing σ-acetylide complexes have been obtained from the reaction between the complex [Rh(PMe₃)₄Cl] (Me = CH₃) and Me₃SnCCC₆H₅ which yields the compound mer,trans-[Rh(PMe₃)₃-(SnMe₃)(-CCC₆H₅)₂] via the intermediate [Rh(PMe₃)₄(-CH₅]. Reaction of [Rh(PMe₃)₄Cl] with one equivalent of Me₃SnCCRCCSnMe3 [R = p-C₆H₄-p-C₆H₄] yields the polymer mer,trans[-Rh(PMe₃)₃(SnMe₃)(-CCRCC-)]_n.