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.
Subject(s)
Coordination Complexes/chemical synthesis , Hydrogenase/metabolism , Iron-Sulfur Proteins/metabolism , Iron/chemistry , Catalysis , Catalytic Domain , Coordination Complexes/chemistry , Crystallography, X-Ray , Electrochemical Techniques , Hydrogen/chemistry , Hydrogenase/chemistry , Iron Compounds/chemistry , Iron-Sulfur Proteins/chemistry , Methane/analogs & derivatives , Molecular Conformation , Phosphines/chemistry , Tellurium/chemistryABSTRACT
In the title compound, C(8)H(6)BrNO(2), the dihedral angle between the planes of the benzene ring and the nitro group is 22.99â (12)°. In the crystal, inversion dimers associated by pairs of short Brâ¯O contacts [3.2319â (17)â Å] occur.