Bimetallic Group 6 Tricarbonyls Containing Rigid Backbone Chelating Ligands Symmetrically Bridged by Bis(diphenylphosphino)alkane

Bimetallic tricarbonyl complexes with chelating bis(diphenylphosphino)ethane or 1,10- phenanthroline bridged by bis(diphenylphosphino)alkane ligands of the type fac-[(L)M(CO)3]2(μ- dppa) (M = Mo (1), W (2); L = dppe, phen; dppa = dppe (a), dppb (b), dpph (c), dppo (d), dppd (e)) were prepared by the reaction of the labile tricarbonyl complexes fac-(L)M(CO)3(py) with the desired dppa which acts as a bridging ligand. These complexes were characterized by FT-IR, 31P and 1H NMR spectroscopies and elemental analysis. A brief study of the thermodynamic stability of some of these complexes in chlorinated hydrocarbons at ambient temperatures was conducted employing FT-IR spectroscopy. All complexes are remarkably stable in solution for a prolonged period of time and show no fac-mer isomerization under conditions employed during this study.