MO-95 NUCLEAR-MAGNETIC-RESONANCE STUDIES ON MOLYBDENUM CARBONYL-COMPLEXES OF ISONITRILES AND AMINES

The Mo-95 NMR spectra of 28 molybdenum carbonyl complexes of isonitriles and amines are reported. Within similar classes of complexes excellent correlation is found between Mo-95 chemical shifts and ligand pi-acceptor ability and, more importantly, complex structures. Application to the analysis of diastereomeric complexes is reported. From analysis of linewidths and relaxation behavior, the surprising result is found that Mo-95 linewidths in isonitrile complexes are not due to coupling to the electric field gradient, but to scalar coupling between the Mo-95 and N-14 nuclei which, in turn, is inversely proportional to the substitution number n in complexes Mo(CO)6-n(CNR)n. A dependence of chemical shift on temperature of 0.3 ppm/-degrees-C is found for Mo(CO)6.