UV-photoelectron spectra of [M(eta(3)-C3H5)(2)] (M = Ni, Pd, Pt) revisited: A quasi-relativistic density functional study

The molecular and electronic structure of [M(eta (3)-C3H5)(2)] (M = Ni, Pd, Pt) has been investigated by means of quasi-relativistic gradient-correcte d density functional calculations. Geometries have been fully optimized by considering both trans and cis arrangements of the bis(eta (3)-allyl) moiet y. Binding energy differences between isomers are always smaller than 0.2 k cal/mol; in particular, cis-[Ni(eta (3)-C3H5)(2)] is computed to be more st able than trans-[Ni(Ni-C3H5)(2)], while a reversed order is obtained for Pd and Pt analogues. Computed geometrical parameters of trans-[Ni(eta (3)-C3H 5)(2)] compare very well with available structural data. Moreover, a new as signment of variable energy photoelectron spectroscopy measurements [Li, X. ; Bancroft, G. M.; Puddephatt, R. J.; Liu, Z. F.; Hu, Y. F.; Tan, K, H. J. Am. Chem. Sec. 1994, 116, 9543-9554] is proposed by assuming that the trans :cis ratio in the gas phase is close to one.