Structure of copper mixed ligand complex with tetramethylethylenediamine as primary ligand by EXAFS

Abstract

Extended X-ray absorption fine structure (EXAFS) has been studied at the Cu K-edge in a copper mixed ligand complex, namely, [Cu(tmen)(acac)](ClO4) (complex I) (were tmen = tetramethylethylenediamine and acac = acetylacetonate). The crystallographic data of the complex I is not available, though it is known to have square pyramidal geometry. Survey of literature shows that crystal structure of an analogous complex, namely, [Cu(tmen)(acac)(H2O)](PF6) (complex II) is available. Tetramethylethylenediamine (tmen) and acetylacetonate (acac) are the common ligands in both the complexes I and II. The analogous complex II has Cu ion in square pyramidal geometry with acac and tmen ligands in the basal plane and H2O molecule in the axial site, O1 and O2 from acac and N1 and N2 from tmen form the square planar structure, O3 from H2O forms the axial site. Hence, the crystal structure of complex II has been used for generation of theoretical model. The theoretical model generated for the analogous complex II has been fitted to the experimental EXAFS data of complex I. The structural parameters for complex I have thus been determined. The values of these parameters have been reported and the coordination geometry of complex I has been depicted in a figure.