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 = CH(2)CH(CO(2)Et)NH(CO(2)Bu-t) with complex [(mu-SCH(2))(2)NCH(2)CH(2)Br]Fe(2)(CO)(6) (2) in THF at room temperature resulted in formation of model complex [(mu-SCH(2))(2)NCH(2)CH(2)SCyt]Fe(2)(CO)(6) (3). Further treatment of 3 with decarbonylating agent Me(3)NO in MeCN at room temperature afforded model complex [(mu-SCH(2))(2)NCH(2)CH(2)SCyt]Fe(2)(CO)(5) (4). Similarly, treatment of 3 with an equimolar mixture of Me(3)NO and Ph(3)P gave model complex [(mu-SCH(2))(2)NCH(2)CH(2)SCyt]Fe(2)(CO)(5)(Ph(3)P) (5) and further treatment of 5 with Me(3)NO produced model complex [(mu-SCH(2))(2)NCH(2)CH(2)SCyt]Fe(2)(CO)(4)(Ph(3)P) (6). More interestingly, model complex [(mu-SCH(2))(2)NCH(CO(2)Et)CH(2)SFe(CO)(2)Cp]Fe(2)(CO)(5) (10) could be synthesized by a "one pot" reaction of the in situ prepared (mu-HS)(2)Fe(2)(CO)(6) (9) with 37% aqueous formaldehyde followed by treatment with the N-deprotected L-cysteinyl iron mercaptide Cp(CO)(2)FeSCH(2)CH(CO(2)Et)NH(2) (8). Complex 8 is new, which was prepared by treatment of complex Cp(CO)(2)FeSCyt (7) with CF(3)CO(2)H followed by 25% aqueous NH(3). 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.
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China. lcsong@nankai.edu.cn
Li-Cheng
LC
Song
Jing
J
Yan
Yu-Long
YL
Li
De-Fu
DF
Wang
Qing-Mei
QM
Hu
D001372:Aza Compounds / Q000737:chemistry*; D001665:Binding Sites; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry*; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D007501:Iron / Q000737:chemistry*; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D001372:Aza Compounds; D007506:Iron-Sulfur Proteins; D009942:Organometallic Compounds; D013438:Sulfhydryl Compounds; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; D003545:Cysteine