EXAFS spectroelectrochemistry of coordination complexes in non-aqueous solutions

Advances in the development of synchrotron radiation as source of high x-ray photon flux for absorption spectroscopy and a reinterpretation of the extended x-ray absorption fine structure (EXAFS) phenomenon have made structural studies of materials in solution relatively straightforward. Efforts to extend the technique to study materials in nonaqueous solution are reported. One system investigated is trans- [Re(DEPE)2Cl2] PF6, (where DEPE represents 1,3-bis(diethylphosphino)ethane). The bis(phosphine)ligands are known to stabilize technetium in several oxidation states; cationic complexes of /sup 99m/Tc are of interest as myocardial imaging agents. EXAFS spectra on the solid complex and on the solution species have been measured. The Fourier transform exhibits one main peak for both the Re-P and Re-Cl interactions. A distance of 2.44 A for Re-P and 2.35 A for Re-Cl has been obtained. The complex [W2(CO)8(S-Benzyl)2] [Et4N]2 has been investigated. The interest in thiolate complexes of tungsten and molybdenum is related to their possible implication in the structure and function of molybdoenzymes