The reactions of methylgermanes with [µ4-Ge{Co2(CO)7}2]: extending the chain of linked GeCo2 triangles

Abstract

Methylgermanes GeMeRH₂(R = H or Me) react with [µ₄-Ge{Co₂(CO)₇}₂]1 to form [µ₄-Ge{Co₂(CO)₇}{Co₂(µ-GeMeR)(CO)₆}](R = H 2a or Me 2b) and [µ₄-Ge{Co₂(µ-GeMeR)(CO)₆}₂](R = H 3a or Me 3b), depending on reaction ratio and time. An alternative synthesis of 2a is from GeMeH₃ and [µ₄-Ge{Co(CO)₄}Co₃(CO)₉]. Corresponding reactions of 1 with silanes or stannanes do not give compounds of type 2 or 3, while the silicon analogue of 1 undergoes fragmentation with germanes, rather than cluster extension. ¹³CO-Exchange, CO-addition, and thermolysis reactions of 1, 2 and 3 are compared. An X-ray structure analysis of 3b[triclinic, space group P, a= 9.607(3), b= 14.796(4), c= 9.476(3)Å, α= 95.83(2), β= 91.94(2), γ= 98.83(2)°, R= 0.044, for 3353 data with I > 2σ(I)] confirms the extended core of four GeCo₂ triangles linked through the Ge apices and the Co–Co edges.