Substituted carbonyl derivatives of the Group VI transition metals. II. Complexes with tritolylphosphines

Abstract

The reactions of the three tritolylphosphines (ortho, meta, and para) with the metal hexacarbonyls, M(CO)₆ (M = Cr, Mo, W), have been investigated under a variety of conditions of temperature, ultraviolet irradiation, and molar ratio. The products were of the general formulae M(CO)₅L and cis and trans M(CO)₄L₂ [L = tri-tolylphosphine] although not all the tetracarbonyl complexes could be prepared. Infrared and nuclear magnetic resonance spectra of these compounds showed interesting trends as the ligand was varied.     In addition, a novel series of derivatives with tri(o- tolyl)phosphine (pot) has been isolated, which on the basis of infrared, N.M.R., and mass spectral data are formulated as π- (pot)M(CO)₃.     The nature of the above reactions and the properties of the products are explained in terms of an argument based on steric effects.