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 C2 with the following unit cell parameters: a=16.474(3) Å, b=11.001(2) Å, c=10.741(2) Å, β=127.21(3)°, 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 π-bonding from alkoxide to tungsten is suggested by the relatively short distance of WO with 1.816(11) Å. Stereochemistry of alkoxide ligand and substantial π-bonding is consistent with the fact that in octahedral d2 systems, two π donors seek a mutual trans arrangement, regardless of the chelating OCH2CH2CH2CH2PPh2 ligand.