[Si(SiMe(3))(3)](3)Ge(9)M(CO)(3)(-) (M = Cr, Mo, W): coordination chemistry with metalloid clusters

Very recently it was shown that the metalloid cluster compound Ge(9)[Si(SiMe(3))(3)](3) (-) 1 can be used for subsequent reactions as the shielding of the cluster core is rather incomplete. So the reaction of 1 with Cr(CO)(3)(CH(3)CN)(3) leads to a cluster enlargement where the chromium atom is incorporated into the cluster core. Here further applications of 1 as a flexible ligand in coordination chemistry are presented where the reaction of 1 with Mo(CO)(3)(EtCN)(3) and W(CO)(3)(CH(3)CN)(3) leads to [(CO)(3)MoGe(9)R(3)](-) 4 and [(CO)(3)WGe(9)R(3)](-) 5 respectively (R = Si(SiMe(3))(3)), showing that 1 can indeed be used as a flexible ligand in coordination chemistry. Structural and electronic properties of the Ge(9)M clusters 4 and 5 are discussed as well as mechanistic aspects of their formation