Insights from 125Te and 57Fe nuclear resonance vibrational spectroscopy: A [4Fe-4Te] cluster from two points of view

Wittkamp, F. and Mishra, N. and Wang, H. and Wille, H.-C. and Steinbrügge, R. and Kaupp, M. and Cramer, S.P. and Apfel, U.-P. and Pelmenschikov, V.

Volume: 10 Pages: 7535-7541
DOI: 10.1039/c9sc02025j
Published: 2019

Iron-sulfur clusters are common building blocks for electron transport and active sites of metalloproteins. Their comprehensive investigation is crucial for understanding these enzymes, which play important roles in modern biomimetic catalysis and biotechnology applications. We address this issue by utilizing (Et4N)3[Fe4Te4(SPh)4], a tellurium modified version of a conventional reduced [4Fe-4S]+ cluster, and performed both 57Fe- and 125Te-NRVS to reveal its characteristic vibrational features. Our analysis exposed major differences in the resulting 57Fe spectrum profile as compared to that of the respective [4Fe-4S] cluster, and between the 57Fe and 125Te profiles. DFT calculations are applied to rationalize structural, electronic, vibrational, and redox-dependent properties of the [4Fe-4Te]+ core. We herein highlight the potential of sulfur/tellurium exchange as a method to isolate the iron-only motion in enzymatic systems. © 2019 The Royal Society of Chemistry.

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