Oxygen-bridged iron-copper assemblies pertinent to heme-copper oxidases: Synthesis and structure of an [Fe[sup III]-(OH)-Cu[sup II]] bridge and EXAFS multiple-scattering effects of linear oxo and nonlinear hydroxo bridges
- Harvard Univ., Cambridge, MA (United States)
- Stanford Univ., CA (United States)
Recently, we have reported the successful use of the GNXAS analysis package to determine reliable metric information (including angles) beyond the first coordination sphere. Of particular present relevance is the significant amplitude enhancement when a backscatter and an intervening atom form a linear or near-linear relationship, such as might occur in an [Fe-X-Cu] bridge. We have used the GNXAS MS protocol to analyze EXAFS data of (1)(ClO[sub 4]) and (3)(ClO[sub 4]) at the Fe K-edge. The EXAFS Fourier transforms (FTs) of the data and of the fit to the data are presented. The fits of both complexes include the two-body contributions Fe-O, Fe-N, and Fe-C[sub [alpha]] and the three-body MS components Fe-N-C[sub [beta]], Fe-O-Cu, and Fe-N-C[sub [gamma]]. The bridge structural differences in linear (1) and nonlinear (3) give rise to dramatic changes in their EXAFS spectra. GNXAS analysis is effective in quantifying the sensitivity of the MS signals to the geometry of the bridging configuration between metal centers. As shown here and for a related case, this technique is relatively sensitive and accurate when the bridge approaches linearity. However, in heme-based Fe-X-Cu bridged assemblies, porphyrin MS effects do not contribute to the Cu EXAFS. 15 refs., 2 figs.
- OSTI ID:
- 6868332
- Journal Information:
- Journal of the American Chemical Society; (United States), Vol. 117:1; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
59 BASIC BIOLOGICAL SCIENCES
COPPER COMPLEXES
SYNTHESIS
IRON COMPLEXES
MOLECULAR STRUCTURE
MULTIPLE SCATTERING
OXIDOREDUCTASES
X-RAY SPECTROSCOPY
COMPLEXES
ENZYMES
ORGANIC COMPOUNDS
PROTEINS
SCATTERING
SPECTROSCOPY
TRANSITION ELEMENT COMPLEXES
400201* - Chemical & Physicochemical Properties
400102 - Chemical & Spectral Procedures
550200 - Biochemistry