Electrochemical and spectroscopic studies of tungstencarbonyl complexes containing nitrogen and phosphorous ligands

the present work deals with the synthesis, spectroscopic investigation and electrochemical behaviour of the compounds [w(co)4(bipy)] (1), [w(co)3(bipy)(dppm)] (2) and [w(co)3(bipy)(dppf)] (3), bipy = 2,2'-bipyridine; dppm = bis(diphenylphosphino)methane; dppf = 1,1'-bis(diphenylphosphino)ferrocene. the ir and 31p{1h} nmr spectroscopic data have shown an octahedral coordination geometry for the tungsten atom with the diphosphines acting as monodentate ligands. the electrochemical behaviour of the complexes was investigated by cyclic voltammetry and controlled potential coulometry. cyclic voltammograms have indicated that the compounds containing diphosphines ligands are more stable towards oxidation than compound (1).