Iron(II)-catecholate complexes of a monoanionic facial N3 ligand: Structural and functional models of the extradiol cleaving catechol dioxygenases
نویسندگان
چکیده
Two biomimetic iron(II)-catecholate complexes, [(Tp)Fe(CatH)] (1) and [(Tp)Fe(DBCH)] (2) (where Tp = hydrotris(3,5-diphenylpyrazole-1-yl)borate, CatH = monoanionic pyrocatecholate and DBCH = monoanionic 3,5-di-tertbutyl catecholate), have been isolated and characterized to study their reactivity towards dioxygen. The single-crystal X-ray structure of (1) reveals a high-spin iron(II) center ligated by the monoanionic facial N3 ligand and a monoanionic catecholate, giving rise to a trigonal bipyramidal coordination geometry. Complex (1) represents the first structurally characterized five-coordinate iron(II)-catecholate complex with an asymmetric bidentate binding motif of monoanionic catecholate. While (1) reacts with dioxygen to form the corresponding iron(III)-catecholate, (2) reacts with dioxygen to give 75 % extradiol and 25 % intradiol cleavage products via an iron(III)-catecholate intermediate species. Complex (2) is a potential functional model of extradiol cleaving catechol dioxygenases.
منابع مشابه
Catalytic and regiospecific extradiol cleavage of catechol by a biomimetic iron complex.
An iron(III)-catecholate complex of a facial tridentate ligand reacts with dioxygen in the presence of ammonium acetate-acetic acid buffer to cleave the aromatic C-C bond of 3,5-di-tert-butylcatechol regiospecifically resulting in the formation of an extradiol product with multiple turnovers.
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