Synthesis and structural characterization of [Bse Me]Ni(PPh 3)(NO), a nickel complex with a bent nitrosyl ligand

Abstract

The nickel nitrosyl compound [Bse Me]Ni(PPh 3)(NO) has been synthesized by the reaction of Ni(PPh 3) 2(NO)Br with potassium bis(2-seleno-1-methylimidazolyl)hydroborate, [Bse Me]K. X-ray diffraction studies demonstrate that (i) the B–H group of the [Bse Me] ligand interacts with the nickel center and (ii) the nitrosyl ligand is bent, with Ni–N–O bond angles of 149.1(3)° and 153.1(3)° for the two crystallographically independent molecules. The bent nature of the nitrosyl ligand in [Bse Me]Ni(PPh 3)(NO) is in marked contrast to the linearity observed for the tris(2-seleno-1-mesitylimidazolyl)hydroborato counterpart [Tse Mes]NiNO (180.0°). Density functional theory geometry optimization calculations demonstrate that the Ni⋯H–B interaction is not responsible for causing the nitrosyl ligand to bend, but rather the difference between [Tse Mes]NiNO and [Bse Me]Ni(PPh 3)(NO) is due to the [Tse Mes] ligand allowing the former molecule to adopt a structure with C 3 symmetry. In contrast, the steric and electronic asymmetry of [Se 2P] donor array of the [Bse Me] and PPh 3 ligand combination prevents [Bse Me]Ni(PPh 3)(NO) from having C 3 symmetry and the nitrosyl ligand bends to stabilize the occupied M–N σ ∗ antibonding orbital.