[CP'(CO)2MN-GEI-MN(CO)2CP']-, THE 1ST GERMANIUM INIDENE COMPLEX

GeI2 reacts with Na[{Cp'(CO)2Mn}H] to form the inidenetype compound [C p'(CO)2Mn-GeI-Mn(CO)2Cp']- (1). The anion 1 contains Ge(0) in a trigon al-planar coordination, embedded between two Cp'(CO)2Mn groups and an iodo ligand. The intrinsic stability of the cumulene [Cp'(CO)2Mn = Ge = Mn(CO)2Cp'] is still apparent in the structure of 1: The Ge-Mn bonds are short (229 pm) while the Ge-I distance is rather long (284 pm). T he inidene-type anion 1 can only be obtained from the above-mentioned reaction if the reaction is quenched by addition of unpolar solvents, thus eliminating starting materials and coproducts. Direct workup of t he reaction mixture instead leads to [Cp'(CO)2MnGeI3]- (2) as the only isolated product. The transformation of 1 into 2, which contains Ge i n the formal oxidation state + 2, necessarily implies redox processes, which are well documented in inidene chemistry.