Aryl Oligogermanes as Ligands for Transition Metal Complexes

The ligand properties of a series of aryl oligogermanes R3Ge-GeAr3, 3-7 [Me3Ge-GePh3 (3), Me3Ge-Ge(pTol)(3) (4), Ph3Ge-GePh3 (5), (C6F5)(3)Ge-GePh3 (6), Ph3Ge-GeMe2GePh3 (7)] for the synthesis of transition metal carbonyl complexes such as R3Ge-GeAr2(R'C6H4-eta(6))M(CO)(3) (M = Cr, 3a-7a; M = Mo, 3b; M = W, 3c) were investigated. The target complexes were obtained in moderate yields using several different synthetic approaches. The physicochemical properties of these new derivatives were investigated by IR, UV/Vis, NMR spectroscopy, electrochemistry, and DFT calculations. The molecular structures of 3c, 4a, and 5a were studied by single-crystal X-ray diffraction analysis. A comparative analysis of donor and acceptor properties of aryl oligogermanes as ligands for transition metal carbonyl complexes is reported.