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Sulfur K-Edge XAS and DFT Calculations on [Fe4S4]2+ Clusters: Effects of H-bonding and Structural Distortion on Covalency and Spin Topology.

Authors :
Dey, Abhishek
Roche, Cara L.
Walters, Marc A.
Hodgson, Keith O.
Hedman, Britt
Solomon, Edward I.
Source :
Inorganic Chemistry. 11/14/2005, Vol. 44 Issue 23, p8349-8354. 6p. 2 Diagrams, 1 Chart, 1 Graph.
Publication Year :
2005

Abstract

Sulfur K-edge X-ray absorption spectroscopy of a hydrogen-bonded elongated [Fe4S4]2+ cube is reported. The data show that this synthetic cube is less covalent than a normal compressed cube with no hydrogen bonding. DFT calculations reveal that the observed difference in electronic structure has significant contributions from both the cluster distortion and from hydrogen bonding. The elongated and compressed Fe4S4 structures are found to have different spin topologies (i.e., orientation of the delocalized Fe2S2 subclusters which are antiferromagnetically coupled to each other). It is suggested that the H-bonding interaction with the counterion does not contribute to the cluster elongation. A magneto-structural correlation is developed for the Fe4S4 cube that is used to identify the redox-active Fe2S2 subclusters in active sites of HiPIP and ferredoxin proteins involving these clusters. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00201669
Volume :
44
Issue :
23
Database :
Academic Search Index
Journal :
Inorganic Chemistry
Publication Type :
Academic Journal
Accession number :
19056265
Full Text :
https://doi.org/10.1021/ic050981m