1-metallacyclopropene complexes and eta(1)-vinyl complexes containing the Cp*W(NO) fragment

The solid-state molecular structure of Cp*W(NO)(CH2SiMe3)(eta(2)-CPhCH2) reveals that the vinyl ligand in this complex exists in a distorted form in the solid state that cannot be readily described by either of the classic eta(1)-vinyl or 1-metallacyclopropene limiting structures, by comparison to other crystallographically characterized vinyl complexes reported in the literature. However, the NMR parameters for the CPhCH2 fragment in this complex are characteristic of those of a 1-metallacyclopropene unit. In addition to these studies, a series of vinyl-containing species of the general formulas Cp*W(NO)(eta(2)-CPhCH2)(X) and Cp*W(NO)(eta(1)-CPh=CH2)(LX) (X = Cl, OTf; LX = O2CPh, (NHBu)-Bu-t, (PPh3)(H)) has been prepared, and the solid-state metrical parameters and solution NMR spectroscopic properties of these complexes have been examined and compared to those of other vinyl-containing complexes reported in the literature. It has been found that the nature of the tungsten-vinyl interaction in these compounds is dependent upon the donor strength of the one-electron (1e) X or 3e LX donor ligands that are also present in the tungsten coordination sphere.