Syntheses and molecular structures of some compounds containing many-atom chains end-capped by tricobalt carbonyl clusters

Abstract

Several complexes containing Co₃ carbonyl clusters end-capping carbon chains of various lengths are described. Pd(0)/Cu(I)-catalysed reactions between {Co₃{μ₃-C(Ctriple bond; length of mdashC)₂Au(PPh₃)}(μ-dppm)(CO)₇ and I(Ctriple bond; length of mdashC)₂SiMe₃ or FcCtriple bond; length of mdashCI gave {Co₃{μ₃-C(Ctriple bond; length of mdashC)xR}(μ-dppm)(CO)₇ [x = 4, R = SiMe₃3; x = 3, R = Fc 8]; treatment of 3 with NaOMe and AuCl(PPh₃) gave 4 [x = 4, R = Au(PPh3)]. Related preparations of Co₃{μ₃-C(Ctriple bond; length of mdashC)₂[Ru(PP)Cp′]}(μ-dppm)n(CO)9−2n [PP = (PPh₃)₂, Cp’ = Cp, n = 1, 5; PP = dppe, Cp′ = Cp∗, n = 1, 6; 0, 7] are also described. Syntheses of bis-cluster complexes {Co₃(μ-dppm)(CO)₇}₂(μ-Cx) (x = 14, 12; 16, 9; 18, 11; 26, 10) – the latter being the longest cluster-capped Cx chains so far described – and the mercury-bridged compounds Hg{(Ctriple bond; length of mdashC)xC[Co₃(μ-dppm)(CO)₇]}₂ (x = 1, 13; 2, 14) are reported. The molecular structures of 7, 12, 13 and 14, as well as of Co₃(μ₃-CCtriple bond; length of mdashCSiMe₃)(μ-dppm)(CO)₆(PPh₃) (15) and Co₃{μ₃-CC(O)OEt}(μ-dppm)(CO)₇ (16), are reported.