Promising catalytic activity of a mononuclear copper(II) complex: Functional mimic for amine and catechol oxidases

Abstract

Mononuclear mixed ligand copper(II) complex, [Cu(L)(Hdpa)](ClO4) [(H(L)) = 2-((2-dimethylamino)ethyliminomethyl)phenol, tridentate NNO donor ligand and Hdpa = 2,2′-dipyridylamine] has been isolated. The coordination geometry is best described as (4+1) square pyramidal with CuN4O chromophore. In solid-state, it displays self-assembled inter-pair dimer due to (i) inter-pair π-π anti-parallel stacking, and (ii) NH⋅⋅⋅O intermolecular hydrogen bonding, and in solution also it is maintained. The reversible change of oxidation state (Cu(II) ⇌ Cu(I)) occurs at high positive redox potential. The present complex acts as good catalyst to convert benzylamine to benzaldehyde and 3,5-di-tert-butylcatechol to 3,5-di-tert-butyl-o-quinone, hence mimicking the functional properties of amine (type-2) and catechol (type-3) oxidases.