Rj. Deeth et Cn. Field, A COMPUTATIONAL STUDY OF METAL-DINITROGEN COORDINATION, Journal of the Chemical Society. Dalton transactions, (13), 1994, pp. 1943-1948
Local density functional theory (DFT) discrete variational Xalpha (DVX
alpha) calculations have been performed on the model metal-dinitrogen
system trans-[MA4(N2)2] (M = Mo, A = PH3 or SH2; M = W, A = PH3) and t
rans-[MClA4(N2)] (M = Mo, A = PH3 or SH2). Molecular-orbital and charg
e density analyses demonstrate a reasonable qualitative correlation be
tween theory and experiment with respect to metal-ligand bonding, N-N
stretching frequencies, and the sites and relative rates of attack on
co-ordinated N2 by protons and organic radicals. Comparisons with ab i
nitio Hartree-Fock theory results for [Mo(PH3)(N2)2] show that the DVX
alpha method gives a better description of the charge distribution. At
tempts to quantify the theoretical predictions via binding-energy calc
ulations have been less successful. Evidently, a more sophisticated DF
T treatment will be required for improved quantitative accuracy.