The molecular configuration of two complexes with σ and π-nickel  carbon bonds.

Abstract

The molecular conformation of two square planar π-pentenylnickel(II) complexes with σ and π nickelcarbon bonds, (π-pentenyl)(diisopropylphenylphosphine) methylnickel(II) and (π-pentenyl)(dimenthylmethylphosphine) methylnickel(II), have been determined from single crystal X-ray data collected at room temperature with counter methods. Molecule I crystallizes in the monoclinic space group P 2 1 / c with four molecules in a unit cell of the dimensions a 8.927(3), b 26,031(9), c 8.718(2)A, β 110.88(2)°;II crystallizes in the orthorhombic system, space group P 2 1 2 1 2 1 , with four molecules in a cell a 14.446(1) b 13.727(1), c 11.895(1)A. Both structures have been refined anisotropically to R values of 6.26 and 3.65%, respectively. The absolute configuration of II has been determined to be R on a 99.5% confidence level. Comments are made on the bonding situation of the π-allylic fragments as well as on the steric conformation of the phosphine ligands. The NiC(σ) bond distances were found to be 1.99(1) in compound I and 1.975(4)A in compound II.