An approach to water-soluble hydrogenase active site models: Synthesis and electrochemistry of diiron dithiolate complexes with 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo 3.3.1 nonane ligand(s)
2006 (English)In: Journal of Organometallic Chemistry, ISSN 0022-328X, E-ISSN 1872-8561, Vol. 691, no 23, 5045-5051 p.Article in journal (Refereed) Published
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 CH3CN. 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 CH3CN/H2O 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.
Place, publisher, year, edition, pages
2006. Vol. 691, no 23, 5045-5051 p.
biomorganic chemistry, diiron dithiolate complexes, electrochemistry, iron-only hydrogenase, triazaphosphaadamantane ligand, fe-only hydrogenases, iron hydrogenase, 1,3,5-triaza-7-phosphaadamantane, coordination
IdentifiersURN: urn:nbn:se:kth:diva-16149DOI: 10.1016/j.jorganchem.2006.08.082ISI: 000242304900030ScopusID: 2-s2.0-33750282563OAI: oai:DiVA.org:kth-16149DiVA: diva2:334191
QC 201005252010-08-052010-08-05Bibliographically approved