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Title: EXAFS Studies of Cobalt(II) Complexes with Amino Acids

Abstract

X-ray K-absorption edges along with their extended X-ray absorption fine structure (EXAFS) have been recorded for Co(II) complexes with amino acids using a laboratory XAFS spectrometer. The samples studied are biologically important because amino acids are very small bio molecules and are the principal building blocks of proteins and enzymes. The samples studied include cobalt glycinate, cobalt alanate, cobalt valinate and cobalt glutamate. Using the experimentally observed X-ray absorption chemical shifts, effective nuclear charge (ENC) and percentage covalency have been estimated and a relative order of covalency amongst the studied complexes established which follows the sequence: alanate > glutamate > glycinate > valinate. Both X-ray absorption near edge structure (XANES) and EXAFS have been utilized to obtain the average near neighbour distances in the samples. Further, the total phase shifts {delta}1 and phase parameters {beta}1 i.e., back scattering phase shifts for these samples have been estimated. The values of {beta}1 support the view that the environment around the central metal ion cobalt is similar in these complexes. The appearance of white lines (WL) at the K-absorption edges in these samples is discussed.

Authors:
 [1];  [2];  [3]
  1. Physics Department, Government Post-Graduate Arts and Science College, Ratlam 457001 (India)
  2. Mandsaur Institute of Technology, Mandsaur 458001 (India)
  3. School of Studies in Physics, Vikram University, Ujjain 456010 (India)
Publication Date:
OSTI Identifier:
21054625
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 882; Journal Issue: 1; Conference: XAFS13: 13. international conference on X-ray absorption fine structure, Stanford, CA (United States), 9-14 Jul 2006; Other Information: DOI: 10.1063/1.2644518; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ABSORPTION SPECTRA; ABSORPTION SPECTROSCOPY; AMINO ACIDS; BACKSCATTERING; CHEMICAL SHIFT; COBALT COMPLEXES; COBALT IONS; COPPER; COVALENCE; ENZYMES; FINE STRUCTURE; K ABSORPTION; MOLECULES; PHASE SHIFT; X-RAY SPECTRA; X-RAY SPECTROSCOPY

Citation Formats

Joshi, S. K., Hinge, V. K., and Shrivastava, B. D.. EXAFS Studies of Cobalt(II) Complexes with Amino Acids. United States: N. p., 2007. Web. doi:10.1063/1.2644518.
Joshi, S. K., Hinge, V. K., & Shrivastava, B. D.. EXAFS Studies of Cobalt(II) Complexes with Amino Acids. United States. doi:10.1063/1.2644518.
Joshi, S. K., Hinge, V. K., and Shrivastava, B. D.. Fri . "EXAFS Studies of Cobalt(II) Complexes with Amino Acids". United States. doi:10.1063/1.2644518.
@article{osti_21054625,
title = {EXAFS Studies of Cobalt(II) Complexes with Amino Acids},
author = {Joshi, S. K. and Hinge, V. K. and Shrivastava, B. D.},
abstractNote = {X-ray K-absorption edges along with their extended X-ray absorption fine structure (EXAFS) have been recorded for Co(II) complexes with amino acids using a laboratory XAFS spectrometer. The samples studied are biologically important because amino acids are very small bio molecules and are the principal building blocks of proteins and enzymes. The samples studied include cobalt glycinate, cobalt alanate, cobalt valinate and cobalt glutamate. Using the experimentally observed X-ray absorption chemical shifts, effective nuclear charge (ENC) and percentage covalency have been estimated and a relative order of covalency amongst the studied complexes established which follows the sequence: alanate > glutamate > glycinate > valinate. Both X-ray absorption near edge structure (XANES) and EXAFS have been utilized to obtain the average near neighbour distances in the samples. Further, the total phase shifts {delta}1 and phase parameters {beta}1 i.e., back scattering phase shifts for these samples have been estimated. The values of {beta}1 support the view that the environment around the central metal ion cobalt is similar in these complexes. The appearance of white lines (WL) at the K-absorption edges in these samples is discussed.},
doi = {10.1063/1.2644518},
journal = {AIP Conference Proceedings},
number = 1,
volume = 882,
place = {United States},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007}
}