ENERGY FACTORED C-O AND N-N FORCE-CONSTANTS FOR THE NI(CO)4-X(N2)X SERIES (X=0-4)

Approximate energy factored force constants for C-O and N-N groups of the Ni(CO)4-x(N2)x series are calculated from ligand effect constants. These force constants are markedly different to those calculated by O zin and co-workers from spectra produced after co-condensing CO, N2 an d Ar at cryogenic temperatures. The discrepancies are traced to errors in the assignment of nu(CO) and nu(NN) bands. The revised assignments and re-calculated force constants for Ni(CO)4-x(N2)x give a much simp ler picture of the bonding trends within the molecules as the level of substitution of CO by N2 increases.