TY - JOUR
T1 - X-ray absorption fine structure study of multinuclear copper(I) thiourea mixed ligand complexes
AU - Gaur, Abhijeet
AU - Shrivastava, B. D.
AU - Srivastava, K.
AU - Prasad, J.
AU - Raghuwanshi, V. S.
PY - 2013
Y1 - 2013
N2 - X-ray absorption fine structure spectra of five copper(I) thiourea complexes [Cu4(thu)6 (NO3)4 (H 2O)4] (1), [Cu4(thu)9 (NO 3)4 (H2O)4] (2), [Cu 2(thu)6 (SO4) H2O] (3), [Cu 2(thu)5 (SO4) (H2O)3] (4), and [Cu(thu)Cl 0.5H2O] (5) have been investigated. Complexes 1 and 3 are supposed to have one type of copper centers in trigonal planar and tetrahedral environment, respectively. Complexes 2 and 4 are supposed to have two types of copper centers, one center having trigonal planar geometry and another center having tetrahedral geometry. The aim of the present work is to show how extended X-ray absorption fine structure (EXAFS) spectra of these complexes, having different types of coordination environment, can be analyzed to yield the coordination geometry around one type of copper centers present in complexes 1 and 3, and two types of copper centers present in complexes 2 and 4. The crystal structure of complex 5 is unavailable due to inability of growing its single crystals, and hence the coordination geometry of this complex has been determined from EXAFS. The structural parameters determined from the EXAFS spectra have been reported and the coordination geometry has been depicted for the metal centers present in all the five complexes. Also, the chemical shifts have been used to determine the oxidation state of copper in these complexes. The X-ray absorption near edge spectra features have also been correlated with the coordination geometry. Also, the presence of both three and four coordinated Cu(I) centers in complexes 2 and 4 has been suggested from a comparison of the intensity of the feature at 8984 eV with those of 1 and 3. Further, in case of complex 5, the high intensity of peak A at 8986.5 eV is found to correspond to the presence of Cl coordinated to the copper center.
AB - X-ray absorption fine structure spectra of five copper(I) thiourea complexes [Cu4(thu)6 (NO3)4 (H 2O)4] (1), [Cu4(thu)9 (NO 3)4 (H2O)4] (2), [Cu 2(thu)6 (SO4) H2O] (3), [Cu 2(thu)5 (SO4) (H2O)3] (4), and [Cu(thu)Cl 0.5H2O] (5) have been investigated. Complexes 1 and 3 are supposed to have one type of copper centers in trigonal planar and tetrahedral environment, respectively. Complexes 2 and 4 are supposed to have two types of copper centers, one center having trigonal planar geometry and another center having tetrahedral geometry. The aim of the present work is to show how extended X-ray absorption fine structure (EXAFS) spectra of these complexes, having different types of coordination environment, can be analyzed to yield the coordination geometry around one type of copper centers present in complexes 1 and 3, and two types of copper centers present in complexes 2 and 4. The crystal structure of complex 5 is unavailable due to inability of growing its single crystals, and hence the coordination geometry of this complex has been determined from EXAFS. The structural parameters determined from the EXAFS spectra have been reported and the coordination geometry has been depicted for the metal centers present in all the five complexes. Also, the chemical shifts have been used to determine the oxidation state of copper in these complexes. The X-ray absorption near edge spectra features have also been correlated with the coordination geometry. Also, the presence of both three and four coordinated Cu(I) centers in complexes 2 and 4 has been suggested from a comparison of the intensity of the feature at 8984 eV with those of 1 and 3. Further, in case of complex 5, the high intensity of peak A at 8986.5 eV is found to correspond to the presence of Cl coordinated to the copper center.
UR - http://www.scopus.com/inward/record.url?scp=84903364008&partnerID=8YFLogxK
U2 - 10.1063/1.4813003
DO - 10.1063/1.4813003
M3 - Article
AN - SCOPUS:84903364008
SN - 0021-9606
VL - 139
JO - The Journal of Chemical Physics
JF - The Journal of Chemical Physics
IS - 3
M1 - 034303
ER -