Heterometallic decanuclear [Fe₆–Ln₄] coordination clusters with enzymatic mimic activity: Synthesis, structures, magnetic properties, and evaluation of catecholase activity

Abstract

Three [Fe 6 -Ln 4 ] clusters are isolated through N-methyldiethanolamine (H 2 mdea) and 3,5-dinitrobenzoic acid (Hdnbz) acting as ligands together with sodium azide. The X-ray study demonstrates that these compounds are isostructural formulated as [Fe 6 Ln 4 (μThe catecholase activity for the clusters (1-3) was also studied in methanol by ultraviolet-visible spectrophotometry via 3,5-di-tertiarybutyl catechol (3,5-DTBC) employed as a model substrate for the identification of the compounds as a functional model for metalloenzymes. During this study, the parameters for catecholase activity are estimated as K cat = 1022.12 (1), 827.76(2), 562.36 (3) h À1 ; KM = 0.6858 (1), 0.6467 (2), 0.4872 (3) M; and V max = 0.2840 (1), 0.2291 (2), 0.1556 (3) M min À1 . In the Fe-4f system, such a type of activity is determined for the first time. The magnetic studies indicate the antiferromagnetic (AF) interactions between the metal centers.