ic301348f_si_002.cif (1.17 MB)

A Nitrogenase Cluster Model [Fe8S6O] with an Oxygen Unsymmetrically Bridging Two Proto-Fe4S3 Cubes: Relevancy to the Substrate Binding Mode of the FeMo Cofactor

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posted on 05.11.2012, 00:00 by Shun Ohta, Yasuhiro Ohki, Takayoshi Hashimoto, Roger E. Cramer, Kazuyuki Tatsumi
An oxygen-encapsulated iron sulfido cluster, [(DmpS)­Fe4S3O]­[(DmpS)­Fe4S3]­(μ-SDmp)2(μ-OCPh3) (2; Dmp = 2,6-(mesityl)2C6H3), has been synthesized by the reaction of the preformed dinuclear iron thiolate/alkoxide [(Ph3CO)­Fe]2(μ-SDmp)2 (1) with 1/8S8 and 1/4H2O in toluene. In the [Fe8S6O] core, the oxygen atom bridges unsymmetrically two incomplete Fe4S3 cubes, and two coordinatively unsaturated iron atoms are weakly bound to mesityl rings. Relevance of the cluster structure of 2 to the nitrogenase FeMo cofactor and its substrate binding mode is discussed.