• Iron and cobalt complexes of 4,4,9,9-tetramethyl-5,8-diazadodecane-2, 11-dione dioxime ligand: Synthesis, characterization and reactivity studies

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      https://www.ias.ac.in/article/fulltext/jcsc/123/06/0839-0846

    • Keywords

       

      Iron; cobalt; oximate ligand; oxidation; catechol cleavage; solid-state structure.

    • Abstract

       

      Two oximate bridged dinuclear complexes [Co$^{\text{II}}_2$ (HL)2](ClO4)2 (1) and [Fe^{text{II}}_2$ (HL)2](ClO4)2 (2), and a biomimetic iron(III)-catecholate complex [FeIII(HL)(DBC)] (3) of a dioxime ligand (H2L = 4,4,9,9-tetramethyl-5,8-diazadodecane-2,11-dione dioxime and DBCH2 = 3,5-di-tert-butylcatechol) were synthesized and characterized. X-ray single-crystal structures of both the dinuclear complexes exhibit an out-of-plane oximate bridge where the six-membered M2(NO)2 ring adopt a boat conformation with the metal ions in a fivecoordinate distorted trigonal bipyramidal geometry. Complexes 1 and 2 react with dioxygen at ambient condition to form the corresponding hydroxo- or oxo-bridged dinuclear cobalt(III) or iron(III) complexes. On the other hand, the iron(III)-catecholate complex (3) activate dioxygen to undergo oxidative C-C bond cleavage of catechol. The selective formation of extradiol catechol cleavage products in the reaction of 3 with dioxygen mimics the functional aspect of extradiol-cleaving catechol dioxygenases. The flexibility of ligand backbone is proposed to control the dioxygen reactivity of metal complexes.

    • Author Affiliations

       

      Oindrila Das1 Sayanti Chatterjee1 Tapan Kanti Paine1

      1. Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, 2A and 2B, Raja S C Mullick Road, Jadavpur, Kolkata 700032, India
    • Dates

       
  • Journal of Chemical Sciences | News

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