INOR 12 |
| A new method to synthesize Fe/S clusters has been developed, using Fe{N(TMS)2}2 (TMS = SiMe3) as the precursor. This new route has allowed us to build Fe/S clusters in non-polar solvents, and resulted in a series of unprecedented cluster structures resembling closely the active sites of nitrogenase and hydrogenase. For instance, the unusual [8Fe-7S] core structure of P-cluster (PN) of nitrogenase was self-assembled, and isolated are [{N(TMS)2}(tmtu)Fe4S3]2(µ6-S){µ-N(TMS)2}2 (1), (NEt4)2[{N(TMS)2}(SAr)Fe4S3]2(µ6-S){µ-N(TMS)2}2 (2) (Ar = 4-tBu-C6H4, 2-SiMe3-C6H4 etc.), and [(SAr){SC(NMe2) 2}Fe4S3]2(µ6-S){µ-N(TMS)}2 (Ar={2,6-(SiMe3)2-C6H4}) (3). Yet another type of [8Fe-7S] cluster, [(SDmp)Fe4S3]2(µ6-S)(µ-SDmp)2(µ-STip)} (4), was synthesized from the reaction between [Fe(Stip)]2(µ-SDmp)2 and S8. This cluster is topologically analogous to FeMo-co, and has an intriguing 5Fe(II)+3Fe(III) oxidation state with a doublet ground state. Unusual [4Fe-4S] clusters, Fe4S4(SDmp)3(THF)3 (5) and Fe4S4(SDmp)3(Imd) (6) (Imd = tetramethyl imidazole), were also isolated, the latter of which models the histidine-bound [4Fe-4S] cluster uniquely found in [NiFe] hydrogenase.
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Frontiers in Organometallic Chemistry
8:25 AM-12:00 PM, Sunday, August 19, 2007 BCEC -- 206 A/B, Oral
Division of Inorganic Chemistry |
