Formation and reactions of mono- and di-substituted derivatives of [µ4-Ge{CO2(CO)7}2], containing functional µ-GeRH or µ-GeRCl groups
Abstract
The reaction of µ4-Ge{Co2(CO)7}2]1 with GeRH3(R = Et or Ph) has been found to give [µ4-Ge{Co2(CO)7}{Co2(CO)6)(µ-GeRH)}]2 or [µ4-Ge{Co2(CO)6(µ-GeRH)}2]3 depending on the stoichiometries and conditions. Analogues of 2 or 3 with µ-GeMeCl groups form from 1 and GeMe(Cl)H2. Reaction of 2 with [Co2(CO)8] gives an open cluster with a µ-Ge(R)Co(CO)4 group which readily condenses to a closo-cluster with a Ge2Co4 core. Analogous reactions of 3 with [Co2(CO)6] ultimately give clusters [Co4(µ4-GeR)2{µ-GeCo2(CO)7}(CO)10] again via more-open intermediates. Corresponding species are obtained from the µ-GeMeCl compounds and [Co(CO)4]–. An X-ray structure analysis of [Co4(µ4-GeEt)2{µ-GeCo2(CO)7}(CO)10] has been performed: triclinic, space group P, a= 10.617(1), b= 16.895(3), c= 9.822(4)Å, α= 104.22(2), β= 94.40(2), γ= 102.03(1)°, Z= 2, R= 0.027, for 3516 data with l > 2σ(l). It reveals a structure consisting of a pseudo-octahedral Ge2Co4 unit, with one of the Co-Co bonds edge-bridged by a µ-GeCo2(CO)7 moiety.