He I and He II photoelectron spectra of trans-[MCl2L2](M = Pd, L = PEt3 or AsEt3; M = Pt, L = NMe3, PMe3, PEt3, or AsEt3) and trans-[PtH(Cl)(PEt3)2], and Hartree-Fock–Slater calculations on model compounds

Abstract

U.v. photoelectron spectra of trans-[MCl₂L₂](M = Pd, L = PEt₃ or AsEt₃; M = Pt, L = NMe₃, PMe₃, PEt₃, or AsEt₃) are reported, as well as Hartree-Fock–Slater calculations on the model compounds trans-[MCl₂(EH₃)₂](M = Pd, E = N or P; M = Pt, E = N). The results from these calculations and empirical assignment criteria such as He I/He II intensity differences and shift effects upon substitution have enabled a full assignment of the upper valence ionizations. Evidence is found for a through-space interaction of phosphorus and arsenic orbitals with orbitals localized on the chloride ligands. The energy levels for ionizations in corresponding complexes of Pd and Pt are rather similar, with the exception of ionizations from orbitals due to π interaction of chloride orbitals with d orbitals of appropriate symmetry. It appears that these interactions are much stronger with Pt than with Pd.