UV-Photoelectron Spectra of [M(µ3-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-corrected density functional calculations. Geometries have been fully optimized by considering both trans and cis arrangements of the bis(eta (3)-allyl) moiety. Binding energy differences between isomers are always smaller than 0.2 kcal/mol; in particular, cis-[Ni(eta (3)-C3H5)(2)] is computed to be more stable 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)-C3H5)(2)] compare very well with available structural data. Moreover, a new assignment 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.