X-ray k-absorption studies of cobalt (II) imidazoles

X-ray K-absorption edges along with their extended x-ray absorption fine structure (EXAFS) have been recorded using a laboratory XAFS spectrometer for the Co(II) imidazoles viz., Co(etImz)2Cl2, Co(iprImz) 2Cl2, Co(tvImz)2Cl2, Co(vImz) 4Cl2, Co(vImz)4(SCN)2, Co(tvImz)4Cl2, and Co(tvImz)4(SCN)2. The chemical shifts for these samples have been reported and the present studies reveal that the anions in Co(ligand)4Cl2/(SCN) 2 do not interact strongly with the metal ion. The studies further show that the complexes have tetrahedral structure in which anions Cl 2/(SCN)2 remain outside the first coordination shell in Co(ligand)4Cl2/(SCN)2 type complexes. The total phase shifts δ1 and phase parameters β1 for these samples have been estimated using the modified graphical method for the determination of bond distances. The values for phase parameter β1 explain the dominance of backscattering in the various complexes studied. © Physica Scripta 2005.