Synthetic and Structural Studies on l-Cysteinyl Group-Containing Diiron/Triiron Azadithiolates as Active Site Models of [FeFe]-Hydrogenases

Five new l-cysteinyl group-containing diiron/triiron azadithiolate complexes (3−6, 10), which could be regarded as the active site models of [FeFe]-hydrogenases, have been successfully synthesized. Treatment of l-cysteinyl sodium mercaptide CytSNa (1, Cyt = CH2CH(CO2Et)NH(CO2Bu-t) with complex [(μ-S...

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Veröffentlicht in:Inorganic chemistry 2009-12, Vol.48 (23), p.11376-11381
Hauptverfasser: Song, Li-Cheng, Yan, Jing, Li, Yu-Long, Wang, De-Fu, Hu, Qing-Mei
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Sprache:eng
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Zusammenfassung:Five new l-cysteinyl group-containing diiron/triiron azadithiolate complexes (3−6, 10), which could be regarded as the active site models of [FeFe]-hydrogenases, have been successfully synthesized. Treatment of l-cysteinyl sodium mercaptide CytSNa (1, Cyt = CH2CH(CO2Et)NH(CO2Bu-t) with complex [(μ-SCH2)2NCH2CH2Br]Fe2(CO)6 (2) in THF at room temperature resulted in formation of model complex [(μ-SCH2)2NCH2CH2SCyt]Fe2(CO)6 (3). Further treatment of 3 with decarbonylating agent Me3NO in MeCN at room temperature afforded model complex [(μ-SCH2)2NCH2CH2SCyt]Fe2(CO)5 (4). Similarly, treatment of 3 with an equimolar mixture of Me3NO and Ph3P gave model complex [(μ-SCH2)2NCH2CH2SCyt]Fe2(CO)5(Ph3P) (5) and further treatment of 5 with Me3NO produced model complex [(μ-SCH2)2NCH2CH2SCyt]Fe2(CO)4(Ph3P) (6). More interestingly, model complex [(μ-SCH2)2NCH(CO2Et)CH2SFe(CO)2Cp]Fe2(CO)5 (10) could be synthesized by a “one pot” reaction of the in situ prepared (μ-HS)2Fe2(CO)6 (9) with 37% aqueous formaldehyde followed by treatment with the N-deprotected l-cysteinyl iron mercaptide Cp(CO)2FeSCH2CH(CO2Et)NH2 (8). Complex 8 is new, which was prepared by treatment of complex Cp(CO)2FeSCyt (7) with CF3CO2H followed by 25% aqueous NH3. All the new complexes 3−6, 8, and 10 were characterized by elemental analysis and various spectroscopic techniques, whereas complexes 5 and 10 were further characterized by X-ray crystallography.
ISSN:0020-1669
1520-510X
DOI:10.1021/ic9006179