The Charge Transfer Spectra of d8 Transition Metal Halide Complexes and the 1849 Å Photolysis of Aqueous PtCl42−

Abstract

The ultraviolet spectra of the d8 complexes PtX42−, AuX4−, and Pd2X62− (X = Cl− or Br−) are reported. The assignments are based on a standard ordering of molecular orbital energy levels and on the trends in the band frequencies as related to the different metals and ligands. In addition to the low intensity d–d bands, two distinct high intensity regions are identified, an initial set of charge transfer ligand to metal bands followed by a sequence of essentially d → p bands. The 1849 Å irradiation of aqueous PtCl42− results in a redox reaction via photoelectron formation with [Formula: see text].The primary photolytic act is interpreted as initial excitation of the d → p transition 1A1g → 1Eu(3) (egπ* → a2uπ*).