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论文类型：期刊论文

发表时间：2006-11-15

发表刊物：JOURNAL OF ORGANOMETALLIC CHEMISTRY

收录刊物：SCIE

卷号：691

期号：23

页面范围：5045-5051

ISSN号：0022-328X

关键字：biomorganic chemistry; diiron dithiolate complexes; electrochemistry; iron-only hydrogenase; triazaphosphaadamantane ligand

摘要：In order to improve the hydro- and protophilicity of the active site models of the Fe-only hydrogenases, three diiron dithiolate complexes with DAPTA ligand(s) (DAPTA=3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonanc), (mu-pdt)[Fe(CO)(2)][Fe(CO)(2)(DAPTA)] (1, pdt = 1,3-propanedithiolato), (mu-pdt)[Fe(CO)(2)(DAPTA)](2) (2) and (mu-pdt)[Fe(CO)(2)(PTA)][Fe(CO)(2)(DAPTA)] (3), were prepared and spectroscopically characterized. The water solubility of DAPTA-coordinate complexes 1-3 is better than that of the PTA-coordinate analogues. With complexes 1-3 as electrocatalysts, the overvoltage is reduced by 460-770 mV for proton reduction from acetic acid at low concentration in CH(3)CN. Significant decrease, up to 420 mV, in reduction potential for the Fe(I)Fe(I) to Fe(I)Fe(0) process and the curve-crossing phenomenon are observed in cyclic voltammograms of 2 and 3 in CH(3)CN/H(2)O mixtures. The introduction of the DAPTA ligand to the diiron dithiolate model complexes indeed makes the water solubility of 2 and 3 sufficient for electrochemical studies in pure water, which show that the proton reduction from acetic acid in pure water is electrochemically catalyzed by 2 and 3 at ca. -1.3 V vs. NHE. (c) 2006 Elsevier B.V. All rights reserved.