H-Ge bond activation by tungsten carbonyls: An experimental and theoretical study

The activation of the Ge-H bond and the formation of several hydride complexes, characterized by high-field resonances, have been detected during the H-1 NMR spectroscopy monitoring of the photochemical reaction of Et3GeH and Et2GeH2 with W(CO)(6) and the norbornadiene complex [W(CO)(4)(eta(4)-nbd)]. The activation of the Ge-H bond of triethylgermane in the photochemical reactions of tungsten(0) complexes has been applied in the hydrogermylation of norbornadiene (nbd), which leads to the formation of endo-triethylgermylnorbornene as the major product. The complex [{W(mu-eta(2)-H-GeEt2)(CO)(4))(2)] has been fully characterized by NMR spectroscopy and by a single-crystal X-ray diffraction study. Evidence for the hydride ligand of the W(mu-eta(2)-H-GeEt2) group has been provided by H-1 NMR spectroscopy (delta = -9.02, (1)J(H-W) = 31 Hz) and by DFT calculations. A DFT study of the structural properties and H-1 NMR chemical shifts of several possible intermediate a and hydride complexes formed during the photochemical reaction of W(CO)(6) and Et2GeH2 has been performed. (C) 2011 Elsevier Ltd. All rights reserved.