Catalytic alcohol oxidation using cationic Schiff base manganeseIII complexes with flexible diamino bridge

Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N'-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV-Vis, and HR ESI-MS techniques. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N'-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Four Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N'-bis(salicy1idene)-1,2-cyclohexanediaminato)] were synthesized and characterized, showing good catalytic activity in oxidation reactions. Among them, Mn-4 complex was the most stable and selected for the oxidation of various alcohols, demonstrating promising potential for practical applications.