Mononuclear Mn(III) complex with sterically constrained phenol-based ligand: Synthesis, structure and catecholase activity

• Published in: Journal of molecular structure 2020-11, Vol.1220, p.128723, Article 128723
• Main Authors: Mandal, Bikramaditya, Haldar, Anwesha, Saha, Rajat, Mandal, Debdas
• Format: Article
• Language: English
• Subjects: Catecholase activity; Characterization; Synthesis; X-ray structure
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2020.128723

A mononuclear Mn(III) complex of a sterically constrained phenol-based tetradentate N2O2 ligand N,Nʹ-dimethyl-N,Nʹ-bi(2-hydroxy-3,5-dichlorobenzyl)-ethylenediamine (H2L) have been reported. Benzoylacetone (bzac) has been used as an ancillary ligands to obtain the mixed ligand mononuclear complex [MnIIIL(bzac)] 1. The syntheses, molecular and supra molecular structure, spectroscopic studies and catecholase activity of the complex are described. Complex 1 crystallizes in orthorhombic space group P212121 with a = 12.935(4) Å, b = 13.536(4) Å and c = 16.804(5) Å. Mn(III) complex acts as an effective catalyst towards the oxidation of 3,5-di-tert-butylcatechol in methanol solvent. The kinetic studies confirm the Kcat value for the oxidation reaction is 2.086 × 103 h−1. Mechanistic study of the catalytic behavior by ESI-MS spectra and estimation of hydrogen peroxide formation suggest that the catalytic process takes place through the reduction of Mn(III) to Mn(II). [Display omitted] •A mononuclear mixed ligand octahedral Mn(III) complex [MnL(bzac)] was synthesized.•The Mn (III) complex has been synthesized by using facially coordinating tetradentate N2O2 ligand together with benzoylacetone as an ancillary ligand.•The crystal structure of this complex was determined from single crystal X-ray diffraction study.•Catecholase activity of the complex was observed.