J. Phys. IV France 7 (1997) C2-639-C2-640
Cu Polyimidazole Thioether Complexes : Comparison of RDF's Reconstructed from XAFS and XRD DataS. Bénazeth1, 2, J. Purans2, 3, D. E. Over4 and J. C. Chottard4
1 LURE, Bât. 209D, 91405 Orsay, France
2 Laboratoire de Chimie Inorganique, UFR Pharmacie, Université Paris XI, 92296 Paris, France
3 ISSP, University of Latvia, Kengaraga 8, 1063 Riga, Latvia
4 Laboratoire de Chimie et de Biochimie pharmacologiques, URA 400, Université Paris V, 75270 Paris, France
Radial distribution functions (RDF) reconstructed from XAFS data (Cu K-edge at low and room temperatures) are compared with RDFs, constructed from XRD crystallographic data of Cu polyimidazole thioether complexes. New EDA software package possibilities are used to reconstruct RDFs: (i) model independent RDF reconstruction, and (ii) multi shell - cumulant fitting. RDFs obtained from XRD data are broadened with Debye Waller factors calculated from XAFS. This way the structural disorder (set of distances) and thermal (vibrational) disorder are quantitatively taken into account in each RDF reconstruction approach. Within experimental error the three sets of RDFs agree well with each other for the Cu-N bonds (N = imidazole) and the Cu-S bonds (S = thioether), which are in the range of 1.8 - 2.3 Å. However, they differ significantly for weakly bound ligands whose bond lengths are in the range 2.3-2.7 Å.
© EDP Sciences 1997