Molybdenum tricarbonyl complexes containing unidentate diphosphine. NMR study of fac-mer isomers and crystal structure of fac-Mo(CO) 3(η 2-phen)(η 1-dppm)

Abstract

The preparation of Mo(CO) 3(η 2-NN)(η 1-dppm) (NN = 2,2′-bipyridyl (bipy), 1,10-phenanthroline (phen), 2,9-dimethyl-1,10-phenanthroline (dmp); dppm = bis(diphenylphosphino)methane) by reactions of Mo(CO) 4(η 2-NN) with dppm have given a fac isomer or a fac-mer mixture depending on the nature of the NN ligand and on the reaction conditions. 1H, 13C and 31P NMR spectroscopy have been used for the characterization of fac and mer isomers. The X-ray structure of one of the phen derivative shows a fac configuration (monoclinic, P2 1 c , a 16.843(3), b 11.220(2), c 19,358(4) Å, β 111.72(2)°, V 3398 Å 3, Z = 4). A transformation in solution has been observed for both isomers, and the fac judged to be more stable than the mer isomer.