Atomic XAFS as a Probe of Electron Transfer within Organometallic Complexes: Data analysis and Theoretical Calculations

Abstract

The atomic XAFS (AXAFS) contributions in the Pt L2,3 X-ray absorption fine structure spectra (XAFS) of [PtCl(NCN)-Z] pincer complexes are shown to be a sensitive probe of changes in the electron density on the Pt atom induced by changes in a para-substituent on the neighboring benzene ring. Such electron density information is similar yet complementary to NMR data. These complexes provide a unique system for examining inductive effects on the AXAFS data, since the geometry around the Pt atom remains unchanged. An initial brief report on this work has been given previously. In this paper a more complete description of the AXAFS isolation technique and theoretical interpretation is given. The isolation of the AXAFS contributions from the XAFS spectrum is extensively described. The dependence of the AXAFS shape and intensity on the Pt atom electron density are shown and discussed in detail.