METAL-OLEFIN BONDING. THE PREPARATION AND PROPERTIES OF GROUP VI METAL CARBONYL COMPLEXES CONTAINING THE LIGANDS 1,6-BIS(DIPHENYLPHOSPHINO)-trans-HEX-3-ENE AND 1,6-BIS(DIPHENYLARSINO)-trans-HEX-3-ENE. THE CRYSTAL AND MOLECULAR X-RAY STRUCTURE OF TRICARBONYL-1,6-BIS(DIPHENYLPHOSPHINO)-tra

Article abstract of DOI:10.1016/S0022-328X(00)87075-8

The complexes M(CO)3(BDPH) and M(CO)3(BDAH) (M=Cr, Mo or W, BDPH=1,6-bis(diphenylphosphino)-trans-hex-3-ene and BDAH=1,6-bis(diphenylarsino)-trans-hex-3-ene), have been prepared.These complexes have been characterised as octahedral complexes in which the tertiary unsaturated diphosphine and diarsine act as tridentate ligands.The complexes have been characterised by infrared, mass spectral, 1H nuclear magnetic resonance, 13C nuclear magnetic resonance and analytical data.The crystal structure of Mo(CO)3(BDPH) has been determined by conventional X-ray diffraction techniques.The straw-coloured needles are orthorhombic, space group Pbca, a 16.991(2), b 20.073(4), c 17.333(2) Angstroem, Z=8.Refinement was by full-matrix least-squares methods and methods and employed anisotropic thermal parameters for all non-hydrogen atoms.Hydrogen atoms were included in calculated positions but were not refined.The final residuals are R=0.048 and R_w=0.048.The compound is monomeric.The unsaturated phosphine ligand is tridentate, through the two phosphorus atoms (trans) and the olefin, and the octahedral coordination is completed by the three carbonyl groups.Distances and angles are Mo-P 2.450, 2.474(4) Angstroem, Mo-CO 2.03, 2.01(1) Angstroem (trans to CO) and 1.97(1) Angstroem (trans to C=C).The olefin coordination has nearly symmetrical Mo-C, 2.504(12), 2.541(14) Angstroem, a short olefin bond 1.38(2) Angstroem, and a twisted olefin configuration.