Structural, spectral, cytotoxic and biocatalytic studies of a dinuclear phenoxo bridged Zn(II) complex from NNO donor tridentate Schiff base

Abstract

• A zinc(II) complex derived from an NNO donor Schiff base system is discussed. • Complex is a centrosymmetric dinuclear phenoxo bridged compound. • Type I halogen interaction present in the crystal system is investigated. • Complex exhibits in vitro cytotoxicity against Dalton's lymphoma ascites cell lines. • Complex shows catecholase like activity in DMF medium. A zinc(II) complex of an NNO donor tridentate Schiff base, 4‑chloro-2-(((3-(methylamino)propyl)imino)methyl)phenol (HL) was synthesised and characterized by different physicochemical methods including single crystal XRD, elemental analysis, IR and electronic spectral analysis. Zinc(II) complex is a centrosymmetric dinuclear phenoxo bridged compound which crystallized in triclinic P 1 ¯ space group. There are a large number of intermolecular hydrogen bonding interactions present in the crystal system which give rise to the formation of a 2D supramolecular assembly and the visual analysis of those intermolecular interactions was done by Hirshfeld surface analysis. Type I halogen interactions, which are quite uncommon, are also discussed based on angular preference, intermolecular distance, and the size of the Cl atom. Complex exhibited negative solvatochromism. Luminescent properties were investigated and quenching of fluorescence was observed which is supported by the quantum yield values. Cytotoxic activity of the complex has been screened in vitro against lymphoma ascites cell lines. In addition, catecholase activity of the complex has been investigated in DMF medium and found that complex was able to catalyze the aerobic oxidation of 3,5-di‑ tert -butylcatechol (3,5-DTBC) to the corresponding quinone.