Solid state structure of WCl2(OCH2CH2CH2CH2PPh2)2 and π-bonding ability of alkoxide in chelating P-O ligand

The solid state structure of the WCl2(OCH2CH2CH2CH2PPh2)(2) (1) is determined by X-ray crystallography. Compound 1 crystallizes in the space group C-2 with the following unit cell parameters: a = 16.474(3) Angstrom, b = 11.001(2) Angstrom, c = 10.741(2) Angstrom, beta = 127.21(3)degrees, and Z = 2. The molecule is described as a distorted octahedral structure with two oxygen atoms trans, two chlorine atoms cis and two phosphorus atoms cis. Substantial pi-bonding from alkoxide to tungsten is suggested by the relatively short distance of W-O with 1.816(11) Angstrom. Stereochemistry of alkoxide ligand and substantial pi-bonding is consistent with the fact that in octahedral d(2) systems, two pi donors seek a mutual trans arrangement, regardless of the chelating -OCH2CH2CH2CH2PPh2 ligand. (C) 2002 Elsevier Science B.V. All rights reserved.