PREPARATION AND PROPERTIES OF GROUP VI METAL CARBONYLS CONTAINING THE LIGAND BIS(DI-o-TOLYL)PHOSPHINOMETHANE. CRYSTAL AND MOLECULAR STRUCTURE OF DICARBONYLBIS(DI-o-TOLYL)PHOSPHINOMETHANECHROMIUM

Article abstract of DOI:10.1016/0022-328X(83)87023-5

Complexes of Group VI metal carbonyls with the ligand bis(di-o-tolyl)phosphinomethane have been prepared and characterised by NMR spectroscopy.The crystal structure of Cr(CO)2(BDT_oM) has been determined by conventional X-ray diffraction techniques.The orange tabular crystals are monoclinic, space group Cc, a 24.197(1), b 8.162(1), c 16.736(1) Angstroem, β 124.14(1)^o, V 2735.8 Angstroem³, Z=4.Refinement by full-matrix least-squares methods employed anisotropic thermal parameters for the heavier atoms and the coordinated o-tolyl group.One carbonyl ligand was positioned from a 'difference' map.The final residual, R, is 0.078 for 1673 observed reflections.The complex is monomeric.The BDT_oM ligand coordinates to chromium through one phenyl ring (three sites) and one phosphorus atom, with two carbonyl groups completing an octahedral 'piano stool'-like arrangement.The coordinated arene ring is planar and is in a staggered arrangement relative to the other donors.The Cr-C(arene) bonds range from 2.166(10) to 2.260(9) Angstroem (average 2.210 Angstroem); the distance of Cr from the plane of the ring is 1.698 Angstroem.The o-methyl carbon and the non-coordinated phosphorus atom are significantly displaced from the ring plane.