PNNL

Abstract

Two doubly charged transition metal complexes, PTðCNÞ2_ 4 and PTðCNÞ2_ 6 commonly found in the condensed phases, are produced as isolated species from solutions to the gas phase using electrospray ionization. Their stability and electronic structures are investigated by photodetachment photoelectron spectroscopy and density functional theory (DFT) calculations. The adiabatic electron detachment energies for the dianions to monoanions are measured to be 1.69 and 3.85 eV for PTðCNÞ2_ 4 and PTðCNÞ2_ 6 , respectively. The magnitude of the repulsive Coulomb barrier is estimated to be _2.5 eV for PtðCNÞ2_ 4 , and _1.7 eV for PTðCNÞ2_ 6 . Well-resolved and distinct peaks are observed in the spectra, yielding rich electronic structure information for these complexes. DFT calculations including scalar relativistic and spin–orbit effects are carried out to determine the geometries and to interpret the observed spectral features. The calculations show that the frontier occupied molecular orbitals are largely metal-based for PTðCNÞ2_ 4 and ligand-based for PTðCNÞ2_ 6 , in contrast to the standard ligand field theory description.