Synthesis and structural characterization of the mono- and diphosphine-containing diiron propanedithiolate complexes related to [FeFe]-hydrogenases. Biomimetic H2 evolution catalyzed by (mu-PDT)Fe2(CO)4[(Ph2P)2N(n-Pr)].
As the new H-cluster models, six diiron propanedithiolate (PDT) complexes with mono- and diphosphine ligands have been prepared and structurally characterized. The monophosphine model complex (mu-PDT)Fe(2)(CO)(5)[Ph(2)PNH(t-Bu)] (1) was prepared by reaction of parent complex (mu-PDT)Fe(2)(CO)(6) (A) with 1 equiv of Ph(2)PNH(t-Bu) in refluxing xylene, whereas A reacted with 1 equiv of Me(3)NO.2H(2)O in MeCN at room temperature followed by 1 equiv of Ph(2)PH to give the corresponding monophosphine model complex (mu-PDT)Fe(2)(CO)(5)(Ph(2)PH) (2). Further treatment of 2 with 1 equiv of n-BuLi in THF at -78 degrees C followed by 1 equiv of CpFe(CO)(2)I from -78 degrees C to room temperature afforded monophosphine model complex (mu-PDT)Fe(2)(CO)(5)[Ph(2)PFe(CO)(2)Cp] (3), whereas the diphosphine model complexes (mu-PDT)Fe(2)(CO)(4)(Ph(2)PC(2)H(4)PPh(2)) (4), (mu-PDT)Fe(2)(CO)(4)[(Ph(2)P)(2)N(n-Pr)] (5) and (mu-PDT)Fe(2)(CO)(4)[(Ph(2)P)(2)N(n-Bu)] (6) were obtained by reactions of A with ca.1 equiv of the corresponding diphosphines in refluxing xylene. All the new model complexes were characterized by elemental analysis, spectroscopy and particularly for 1 and 3-6 by X-ray crystallography. On the basis of electrochemical and spectroelectrochemical studies, model 5 was found to be a catalyst for HOAc proton reduction to H(2), and for this electrocatalytic reaction an ECCE mechanism was proposed.
Song
Li-Cheng
LC
Department of Chemistry, State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China. lcsong@nankai.edu.cn
Li
Chang-Gong
CG
Ge
Jian-Hua
JH
Yang
Zhi-Yong
ZY
Wang
Hu-Ting
HT
Zhang
Juan
J
Hu
Qing-Mei
QM
D032701:Biomimetics; D002384:Catalysis; D018360:Crystallography, X-Ray; D004563:Electrochemistry; D006859:Hydrogen / Q000378:metabolism*; D006864:Hydrogenase / Q000737:chemistry* / Q000378:metabolism; D058085:Iron Compounds / Q000138:chemical synthesis / Q000737:chemistry; D007506:Iron-Sulfur Proteins / Q000737:chemistry* / Q000378:metabolism; D008024:Ligands; D010084:Oxidation-Reduction; D010720:Phosphines / Q000737:chemistry*; D011407:Propane / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism
D058085:Iron Compounds; D007506:Iron-Sulfur Proteins; D008024:Ligands; D010720:Phosphines; D013438:Sulfhydryl Compounds; C522648:propanedithiolate; D006859:Hydrogen; C118830:iron hydrogenase; D006864:Hydrogenase; D011407:Propane