title: The electronic structure of the tris(ethylene) complexes [M(C2H4)3] (M=Ni, Pd, and Pt): a combined experimental and theoretical study.
abstract: In this article we analyze in detail the electronic properties of the D(3h)-symmetric tris(ethylene) complexes of nickel, palladium, and platinum ([M(C(2)H(4))(3)] M=Ni, Pd, Pt). In the case of [Pd(C(2)H(4))(3)] the analysis is based on new experimental IR and Raman spectra for the matrix-isolated molecules and in all cases on the results of quantum-chemical (DFT) calculations. The experimental spectra collected for [Pd(C(2)H(4))(3)] provide evidence for several previously unobserved vibrational modes, including the in-phase and out-of-phase nu(C-C) and delta(CH(2)) modes, and the in-phase nu(M-C) mode. Special consideration is given to possible inter-ligand interactions. The interaction force constant f(CC,CC) between two C(2)H(4) ligands can be directly estimated from the spectra, and its very small value (0.002 N m(-1)) indicates the absence of any significant inter-ligand interaction. An analysis of the topology of the theoretical electron density distribution, rho(r), and the corresponding Laplacian, nabla(2)rho(r), for [Pd(C(2)H(4))(3)] and its lighter and heavier homologues [Ni(C(2)H(4))(3)] and [Pt(C(2)H(4))(3)], respectively, is in full agreement with the conclusions drawn from the experimental results. The combined experimental and quantum-chemical results provide detailed insights in the electronic properties of these prototypical ethylene complexes.
authors: Institut für Technische Chemie und Polymerchemie, Universität Karlsruhe, Engesserstrasse 20, 76131 Karlsruhe, Germany.
authors: Nicole
authors: N
authors: Hebben
authors: Hans-Jörg
authors: HJ
authors: Himmel
authors: Georg
authors: G
authors: Eickerling
authors: Carmen
authors: C
authors: Herrmann
authors: Markus
authors: M
authors: Reiher
authors: Verena
authors: V
authors: Herz
authors: Manuel
authors: M
authors: Presnitz
authors: Wolfgang
authors: W
authors: Scherer