The formation of a σ-bond complex vs. an oxidation addition product in reaction of [M(CO)4(η4-nbd)] (M = W, Mo) and H–EEt3 (E = Si, Ge, Sn): DFT optimized structures and predicted chemical shifts of hydride ligands

• Structures of the sigma–bond complexes of Mo(0) and W(0) have been optimized by DFT.
• Structures of the intermediate complexes for hydrosilylation have been optimized.
• Structures of the intermediate complexes for hydrogermylation have been optimized.
• Structures of the intermediate complexes for hydrostannation have been optimized.
• Values of the NMR chemical shifts of the hydride ligands have been calculated.

Density functional theory calculations have been employed to understand the bonding and structural features of the key intermediate complexes formed during the catalytic cycle for the hydrogermylation, hydrosilylation and hydrostannation of norbornadiene (nbd) in the photochemical reaction of the tungsten(0) and molybdenum(0) carbonyl complex [M(CO)4(η4-nbd)] (M = Mo, W) and H–EEt3 (E = Si, Ge, Sn). The structure of the σ-bond complexes [M(CO)3(η2-H–EEt3)(η4-nbd)] (1) and the seven-coordinate hydride complexes [MH(EEt3)(CO)3(η4-nbd)] (2) have been optimized. The calculated values of the chemical shift for the σ-bond proton in complex 1 and the terminal hydride ligand in the oxidative addition product complex 2 have been compared with recently published experimental data for complexes of this type.

The structure of the σ-bond complexes [M(CO)3(η2-H–EEt3)(η4-nbd)] (M = Mo, W; E = Si, Ge, Sn) and the seven-coordinate hydride complexes [MH(EEt3)(CO)3(η4-nbd)] have been optimized by DFT calculation. The calculated values of the chemical shift have been compared with recently published experimental data for complexes of this type.Figure optionsDownload as PowerPoint slide