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 1H NMR spectroscopy monitoring of the photochemical reaction of Et3GeH and Et2GeH2 with W(CO)6 and the norbornadiene complex [W(CO)4(η4-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(μ-η2-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(μ-η2-H–GeEt2) group has been provided by 1H NMR spectroscopy (δ = −9.02, 1JH–W = 31 Hz) and by DFT calculations. A DFT study of the structural properties and 1H NMR chemical shifts of several possible intermediate σ and hydride complexes formed during the photochemical reaction of W(CO)6 and Et2GeH2 has been performed.

The activation of the Ge–H bond of Et3GeH and Et2GeH2 in the photochemical reaction with W(CO)6 and [W(CO)4(η4-nbd)] has been observed by 1H NMR spectroscopy. The complex [{W(μ-η2-H–GeEt2)(CO)4}2] has been isolated and characterized by NMR spectroscopy and by a single-crystal X-ray diffraction study. The activation of the Ge–H bond of triethylgermane has been applied in the hydrogermylation of norbornadiene. The geometry of several possible intermediate σ and hydride complexes formed in reaction of W(CO)6 and Et2GeH2 was estimated by DFT calculations.Figure optionsDownload as PowerPoint slideHighlights
► The photochemical reaction of germanes with tungsten carbonyls has been studied.
► The activation of the Ge–H bond of germanes has been observed by 1H NMR spectroscopy.
► The structure of complex [{W(μ-η2-H–GeEt2)(CO)4}2] has been resolved by X-ray method.
► The geometry of complexes containing the W–Ge bond was estimated by DFT method.
► The 1H NMR chemical shifts of the hydride ligands have been calculated.