Oxidation of Organic Functionalities by PhI(OAc)2 Catalysed by Magnetically Separable Fe3O4@dopa-Supported Mn(III) Complexes: Combined Experimental and Theoretical Approach

Three newly designed ligands N, N′-bis (3, 5-diX)-2, 2-dimethylpropane-1, 3 diamine, where X=Cl/Br/I (H2L1-H2L3) having N2O2binding sites, have been chosen to synthesize mononuclear manganese(III) complexes 1–3 with an aim to study their catalytic activity towards oxidation of various substrates using PhI(OAc)2as a terminal oxidant. All these complexes have been characterized by routine physico-chemical techniques. Complexes 1 (MnL1Cl ) and 2 (MnL2Cl ) have further been structurally characterized by X-ray single crystal structure analysis. Detailed analysis of ESI-MS, UV-Vis and cyclic voltammetry studies along with theoretical calculations helped us to put forward probable mechanistic pathway for these efficient catalytic reactions. Complex 1exhibited the highest catalytic efficiency in every reaction and therefore it was selected for building a magnetically separable catalyst by attaching it to surface modified magnetic nanoparticles. The new Fe3O4@dopa@MnL1Cl(dopa=dopamine hydrochloride) [FDM-1] catalyst was characterized by solid state UV-VIS, FT-IR, SEM, TEM, TGA, PXRD, EDX and SQUID analyses. The catalytic activity towards oxidation of various substrates by FDM-1 was studied using PhI(OAc)2 and results indicated excellent efficiency along with reusability.