Chemistry of polynuclear metal complexes with bridging carbene or carbyne ligands. Part 59. Reactions of the alkylidyne compounds [M(CR)(CO)2{HB(pz)3}][M = Cr, Mo, or W, R = C6H4Me-4; M = W, R = Me, HB(pz)3= hydrotris(pyrazol-1-yl)borate] with d10 complexes; crystal structure of [PtW2(µ-CMe)2(CO)4{HB(pz)3}2]

Treatment of the compound [W(CMe)(CO)2{HB(pz)3}][{HB(pz)3}= hydrotris(pyrazol-1-yl)borate] with [Ni(cod)2](cod = cyclo-octa-1,5-diene) or [Pt(C2H4)3] affords the trimetal complexes [M′W2(µ-CMe)2(CO)4{HB(pz)3}2](M′= Ni or Pt). Similarly, reactions between the species [M (CC6H4Me-4)(CO)2{HB(pz)3}](M = Cr, Mo, or W) and [Pt(C2H4)3] yield the related compounds [PtM2(µ-CC6H4Me-4)2(CO)4{HB(pz)3}2]. The molecular structure of [PtW2(µ-CMe)2(CO)4{HB(pz)3}2] has been established by X-ray diffraction. The molecule has a nearly linear W–Pt–W spine [172.8(1)°], with mean Pt–W separations of 2.716 A. Each metal–metal bond is bridged by an ethylidyne group [mean values µ-C–W 1.885, µ-C–Pt 2.040 A] and semi-bridged by a carbonyl ligand [W–C–O 166°]. The dihedral angle between the two dimetallacyclopropene rings is 79°. Each tungsten atom carries a terminally bound CO ligand and a HB(pz)3 group. If the metal–metal bonds are ignored, each tungsten is in a pseudo-octahedral environment defined by the three nitrogen atoms of its associated HB(pz)3 ligand, the two CO groups and a µ-CMe fragment. A gold salt [AuW2(µ-CMe)2(CO)4{HB(pz)3}2][PF6] has been obtained by treating [W(CMe)(CO)2{HB(pz)3}] with [AuCl(tht)](tht = tetrahydrothiophene) in the presence of TIPF6. Reactions between the complexes [M(CR)(CO)2{HB(pz)3}](M = Cr, Mo, or W, R = C6H4Me-4; M = W, R = Me) and [Pt(C2H4){P(OMe)3}2] give dimetal compounds [PtM(µ-CR)(CO)2{P(OMe)3}2{HB(pz)3}], but only the ethylidyne-bridged platinum–tungsten compound is reasonably stable in solution. A molybdenum–platinum salt formulated as [PtMo{µ-σ:η3-CH(C6H4Me-4)}(CO)2{P(OMe)3}2{HB(pz)3}][BF4] has also been prepared. Spectroscopic data for the new compounds are reported.