Inorganic Chemistry, Vol.38, No.1, 38-43, 1999
Conformational influence of dithiocarbazinic acid bishydrazone ligands on the structure of Zinc(II) complexes: A comparative XANES study
(1,2-Ethanediyliden)-bis(S-methylhydrazonecarbodithionate) ligands la-g form zinc chelates with [ZnN2S2] units, as shown by means of IR, NMR, XPS, X-ray crystal structure analysis, and Zn and N K-edge XANES. The conformation of ligands la-g strongly determines the structure of the corresponding zinc complexes 2a-g. Powder samples of these complexes were studied by Zn K-edge XANES. The Zn K-edge XANES results agree with those of X-ray crystal structure data, when available. A tetrahedral ligand environment was confirmed fur only one complex (2a). The other zinc chelates (2b-g) show dimeric structures with square pyramidal complex geometry. With pyridine, five-coordinated zinc complexes 3a-c form, as shown by Zn K-edge XANES in comparison with X-ray crystal structure data. XANES studies afford considerable advantage for obtaining structural information, in particular when crystals of sufficient quality cannot readily be obtained.
Keywords:X-RAY-ABSORPTION;MOLECULAR-STRUCTURE;TRANSITION-METALS;NEAR-EDGE;CO;ZN;DERIVATIVES;CRYSTAL;CU;NI