VANADIUM-METAL BONDS IN CARBONYLVANADIUM COMPLEXES: A 51V NMR SPECTROSCOPIC INVESTIGATION

Article abstract of DOI:10.1016/S0022-328X(00)99119-8

The complexes (ERm =SnPh3, SnEt3, PbPh3, AuPPh3), and 2 (E=Sn, Pb), and 5-C5H5)(EPh3)(CO)3>(E=Si, Ge, Sn, Pb) have been prepared and investigated by 51V NMR spectroscopy.Shielding of the vanadium nucleus decreases in the order Sn>Ge>Si>Pb as a result of counteracting effects upon the paramagnetic deshielding term.The trends are discussed in the general context of molecular parameters (polarizability, covalency, electronegativity, and ligand strength) influencing metal shielding in transition metal carbonyl derivatives.In the case of , ion pair formation (⁺<(CO)6>^-) rather than seven-coordination is predicted. 5-C5H5)(SnPh3)(CO)3>^- extends the low-frequency region of the δ(51V) scale to -2054 ppm relative to VOCl3.