title: Synthesis, characterization, and electrochemical properties of diiron propaneditellurolate (PDTe) complexes as active site models of [FeFe]-hydrogenases.
abstract: Parent complex (μ-PDTe)Fe(2)(CO)(6) (1, PDTe = μ-TeCH(2)CH(2)CH(2)Te-μ) is prepared via a new synthetic route involving the reaction of (μ-Te(2))Fe(2)(CO)(6) with Et(3)BHLi, followed by treatment of (μ-LiTe)(2)Fe(2)(CO)(6) with Br(CH(2))(3)Br in a 43% yield. Further reactions of 1 with 1 equiv of monophosphines in the presence of the decarbonylating agent Me(3)NO afford the corresponding monophosphine-substituted complexes (μ-PDTe)Fe(2)(CO)(5)(L) (2, L = PPh(3); 3, PPh(2)H; 4, PMe(3)) in 37%-47% yields, whereas the N-heterocyclic carbene I(Mes)-monosubstituted complex (μ-PDTe)Fe(2)(CO)(5)(I(Mes)) (5) can be prepared in a 26% yield by treatment of 1 with the in situ generated I(Mes) from the 1,3-bis(mesityl)imidazolium salt I(Mes)·HCl and n-BuLi. While the diphosphine-bridged single-butterfly complexes (μ-PDTe)Fe(2)(CO)(4)(dppm) (6) and (μ-PDTe)Fe(2)(CO)(4)(dppn) (7) can be prepared in 28% and 21% yields by treatment of 1 with 1 equiv of the corresponding diphosphines in refluxing xylene, treatment of 1 with 0.5 equiv of diphosphines in the presence of Me(3)NO results in the formation of the corresponding diphosphine-bridged double-butterfly complexes [(μ-PDTe)Fe(2)(CO)(5)](2)(dppp) (8), [(μ-PDTe)Fe(2)(CO)(5)](2)(dppb) (9), and [(μ-PDTe)Fe(2)(CO)(5)](2)(dppf) (10) in 25-37% yields. All the new substituted model complexes 2-10 are characterized by combustion analysis and spectroscopy, and particularly for 2, 3, 5, and 7-10, by X-ray crystallography. In addition, a comparative study on the electrochemical and electrocatalytic properties of the PDTe-type model complexes 1 and 7 with their corresponding selenium and sulfur analogs are reported.
authors.affiliation: Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China. lcsong@nankai.edu.cn
authors.forename: Li-Cheng
authors.initials: LC
authors.lastname: Song
authors.forename: Qian-Li
authors.initials: QL
authors.lastname: Li
authors.forename: Zhan-Heng
authors.initials: ZH
authors.lastname: Feng
authors.forename: Xiao-Jing
authors.initials: XJ
authors.lastname: Sun
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Xie
authors.forename: Hai-Bin
authors.initials: HB
authors.lastname: Song
mesh_terms: D002384:Catalysis; D020134:Catalytic Domain; D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D055664:Electrochemical Techniques; D006859:Hydrogen / Q000737:chemistry; D006864:Hydrogenase / Q000737:chemistry / Q000378:metabolism*; D007501:Iron / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry / Q000378:metabolism*; D008697:Methane / Q000031:analogs & derivatives; D008968:Molecular Conformation; D010720:Phosphines / Q000737:chemistry; D013691:Tellurium / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D058085:Iron Compounds; D007506:Iron-Sulfur Proteins; D010720:Phosphines; C030011:carbene; D006859:Hydrogen; D007501:Iron; C118830:iron hydrogenase; D006864:Hydrogenase; C044646:phosphine; D013691:Tellurium; D008697:Methane