@article{12a8a5a31d24448b9da53602629ac3ab,
title = "The influences of carbon donor ligands on biomimetic multi-iron complexes for N2reduction",
abstract = "The active site clusters of nitrogenase enzymes possess the only examples of carbides in biology. These are the only biological FeS clusters that are capable of reducing N2 to NH4+, implicating the central carbon and its interaction with Fe as important in the mechanism of N2 reduction. This biological question motivates study of the influence of carbon donors on the electronic structure and reactivity of unsaturated, high-spin iron centers. Here, we present functional and structural models that test the impacts of carbon donors and sulfide donors in simpler iron compounds. We report the first example of a diiron complex that is bridged by an alkylidene and a sulfide, which serves as a high-fidelity structural and spectroscopic model of a two-iron portion of the active-site cluster (FeMoco) in the resting state of Mo-nitrogenase. The model complexes have antiferromagnetically coupled pairs of high-spin iron centers, and sulfur K-edge X-ray absorption spectroscopy shows comparable covalency of the sulfide for C and S bridged species. The sulfur-bridged compound does not interact with N2 even upon reduction, but upon removal of the sulfide it becomes capable of reducing N2 to NH4+ with the addition of protons and electrons. This provides synthetic support for sulfide extrusion in the activation of nitrogenase cofactors.",
author = "Nagelski, {Alexandra L.} and Fataftah, {Majed S.} and Bollmeyer, {Melissa M.} and McWilliams, {Sean F.} and MacMillan, {Samantha N.} and Mercado, {Brandon Q.} and Lancaster, {Kyle M.} and Holland, {Patrick L.}",
note = "Funding Information: This work was funded by the National Institutes of Health (GM-065313 to P. L. H.) and R35GM124908 (to K. M. L.). A. L. N. was supported in part by a Berson Graduate Research Fellowship. M. M. B. is an NSF Graduate Research Fellow. We thank Dr Nicholas Bingham and Prof. Peter Schiffer for magnetometry measurements. We thank Dr Daniel DeRosha for thoughtful discussion that contributed to the synthetic improvement of 1. We thank Reagan Hooper for assistance with calculations. We thank Ragnar Bj{\"o}rnsson for helpful discussions on calculations, and for sharing pre-publication data on nitrogenase calculations. We thank Dr Kazimer Skubi for thoughtful feedback on the manuscript. We thank the Yale Center for Research Computing for guidance and use of the research computing infrastructure. XAS data were obtained at SSRL, which is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract no. DE-AC02-76SF00515. The SSRL Structural Molecular Biology Program is supported by the Department of Energy's Office of Biological and Environmental Research and by NIGMS (including P41GM103393). The work at SSRL was also supported by the U.S. Department of Energy Office of Basic Energy Sciences proposal no. 100487. Publisher Copyright: {\textcopyright} 2020 The Royal Society of Chemistry.",
year = "2020",
month = dec,
day = "21",
doi = "10.1039/d0sc03447a",
language = "English (US)",
volume = "11",
pages = "12710--12720",
journal = "Chemical Science",
issn = "2041-6520",
publisher = "Royal Society of Chemistry",
number = "47",
}