60911-45-7Relevant academic research and scientific papers
An Investigation of Adduct Complexes of M(S2CNEt2)2(CO)2 (M = Mo, W) by 95Mo and 183W N.M.R. Spectroscopy
Young, Charles G.,Enemark, John H.
, p. 997 - 1006 (2007/10/02)
The seven-coordinate adducts M(S2CNEt2)2(CO)2L and 2-μ-L (M = Mo, W; L below), derived from the 16-electron complexes M(S2CNEt2)2(CO)2, have been investigated by 95Mo and 183W n.m.r. spectroscopy.The molybdenum and tungsten adducts exhibit resonances in the regions from 310 to -430 and from -465.5 to -1500 ppm, respectively.All the resonances are shielded relative to those of the M(S2CNEt2)2(CO)2 precursors.The dependence of the nuclear shielding on L is as follows.For M = Mo: NH2NHSO2C6H4Me less than Cl- less than OPPh3 less than μ-pyrazine less than pyridine less than NH2NHCOPh less than NH2NMe2 less than μ-NH2NHMe less than μ-NH2NH2 less than μ-NH2CH2CH2NH2 less than NH3 less than N3- less than F- less than AsPh3 less than PPh3 less than SbPh3 less than PPh2Et less than PPh2Me less than PMe3 less than P(OPh)3 less than P(OEt)3 less than P(OMe)3 less than CO.For M = W; NH2NHCOPh less than AsPh3 less than Ph2PCH2PPh2 less than PPh3 less than PPh2Et less than Ph2PCH2CH2PPh2 less than PPh2Me less than PMe3 less than P(OPh)3 less than P(OEt)3 less than P(OMe)3 less than CO.The OPPh3, halide and nitrogen donor ligand adducts participate in a dynamic equilibrium with Mo(S2CNEt2)2(CO)2 on the n.m.r. time scale.The remaining adducts do not exhibit such behaviour.The chemical shifts of both the molybdenum and tungsten adducts are correlated with the ?-acceptor ability of the ligand, L, and the stereochemistry of the adducts.A linear relationship between the chemical shifts of analogous molybdenum and tungsten complexes is observed; the equation of the line is δ(183W) = 1.46δ(95Mo)-857.5.
