Iron (III) complex exhibiting efficient catechol oxidase activity: Experimental, kinetic and theoretical approach

The catecholase activity, DFT calculations, Hirshfeld surface analysis and docking studies were performed on hexanuclear iron(III) cluster, [Fe6III(µ3-O)(edteH)2(piv)6(N3)2] (1) (where H4edte = N,N,N′,N′-tetrakis(2-hydroxyethyl)ethylenediamine and piv = pivalic acid). The catecholase activity was evaluated in acetonitrile through the UV–vis spectrophotometry through 3,5-di-tert-butylcatechol (3,5-DTBC) and calculated as Kcat = 1461.03 h−1. As far as we know, that it is first hexnuclear iron cluster with catecholase activity. DFT calculations are in line with the experimental evaluation of the catecholase activity in terms of the percent contribution of HOMO and LUMO. Further, DFT calculations (vide-infra) provide best justification to the catecholase activity. Hirshfeld surface analysis mapped over a dnorm range – 0.5 Å to 1.5 Å displays a plenty of non-covalent interactions in the molecular units. The docking study reveals various theoretical features like hydrogen bonding, free binding energy (FEB), and hydrophobic interaction between the complex and the DNA. The accessible surface residues exhibit a favoured binding of 1 in between A-T base pairs and also it is seen that a DNA molecule accommodates the complex between both the base pairs of the DNA helix.