The Near- and Mid-Infrared Spectrum of the Creutz-Taube Ion in Aqueous Solution: An Application of FTIR Spectroelectrochemical Techniques

Abstract

Near- and mid-infrared studies of the Creutz-Taube ion by spectroelectrochemical techniques have facilitated the characterization of a low wavenumber electronic transition at 2000 cm-1 with ∊ ≈ 300 dm3 mol-1 cm-1 and full width at half height of ca. 1400 cm-1. The infrared spectra of {[Ru(NH3)5]2 pyrazine}n+, n = 4, 5, or 6, have been recorded in solution under identical conditions, the spectrum of the mixed-valence salt (n = 5) being shown to be intermediate between those of the oxidized and reduced forms of the complex. Thus, on the vibrational time scale the odd electron is fully delocalized between the two ruthenium centers, a conclusion in keeping with that based on other spectroscopic ..