Tricobalt carbonyl clusters containing C-n (n=2, 4, 6) ligands

Abstract

Treatment of Co3(3-CBr)(-dppm)(CO)7 with zinc dust in refluxing thf afforded Co6(6-C2)(-dppm)2(-CO)(CO)12 (5), containing two Co3 triangles which are linked by a short Co-Co bond and the C2 ligand. The Pd(0)/Cu(I)-catalyzed reactions of Co3(3-CBr)(-dppm)(CO)7 or Co3(3-CBr)(CO)9 with Co3{3-C(CC)nAu(PPh3)}(-dppm)(CO)7 (n = 1, 2, respectively) gave {Co3(-dppm)(CO)7}2(3:3-CCCC) (6) and the unsymmetrical C6 derivative {(OC)9Co3}{3:3-C(CC)2C}{Co3(-dppm)(CO)7} (4). The former reacted further with dppm to give {Co3(-dppm)(CO)7}2(3:3-CCCC)(-dppm) (7), in which the two Co3 clusters are bridged by the third dppm ligand.