Group 6 homo-bimetallic carbonyl complexes containing polydentate phosphine ligands

Article abstract of DOI:10.1016/0022-328X(95)05574-4

The group 6 homo-bimetallic carbonyl complexes (M = Cr, Mo or W; Pf-Pf-Pf = PhP(CH2CH2PPh2)2) and (M = Cr, Mo or W; P-Pf3 = P(CH2CH2PPh2)3), were prepared by the chemical oxidation method with TMNO (Me3NO*2H2O) as initiator, and by the labile ligand substitution method with NBD (NBD = norbornadiene) as labile ligand.Crystals of the five-membered chelating ring compounds, (Ia), are monoclinic, with space group P2₁/c, and with a = 16.116(4), b = 14.493(4), c = 18.015(7) Angstroem, β = 96.33(3) deg, Z = 4 and R = 0.093 for 1633 observed reflections.Crystals of the eight-membered chelating ring compound, (II), are monoclinic, with space group P2₁/n, and with a = 12.812(2), b = 22.807(4), c = 15.611(2) Angstroem, β = 90.84(1) deg, Z = 4 and R = 0.050 for 3907 observed reflections.Crystals of the double chelating ring compound 1/n, and with a = 11.618(2), b = 17.526(3), c = 26.080(3) Angstroem, β = 98.48(1) deg, Z = 4 and R = 0.033 for 4936 observed reflections.The M-P bond lengths, M-P-C and P-C-C bond angles in the eight-membered ring were found to be greater than the corresponding ones in the five-membered ring, revealing the larger ring strain for the eight-membered chelating ring.Keywords: Chromium; Molybdenum; Tungsten; Group 6 complexes; Homo-bimetallic complex; Metal carbonyl derivative