The first alternating MnII–MnIII 1D chain: structure, magnetic properties and catalytic oxidase activities

Abstract

An unprecedented one-dimensional mixed-valence chain, [{MnIII(L)2}{MnII(bpy)2}(ClO4)(H2O)0.5]∞ (H2L = N-salicylidene-l-alanine and bpy = 2,2′-bipyridine), has been synthesized. The complex has been characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction analysis, and variable-temperature magnetic measurements. The structural analysis reveals that the [Mn(bpy)2]2+ unit is linked to the pendent carboxylate arm of the [MnIII(L)2]- unit to produce a unique syn-anti carboxylate bridged 1D coordination polymer. Variable-temperature (2-300 K) magnetic susceptibility measurements show the presence of antiferromagnetic interaction between the MnIII and MnII centres with J = -0.98(2) cm-1. Using 3,5-di-tert-butylcatechol (3,5-DTBC) and o-aminophenol (OAPH) as the substrates, the catecholase-like activity and phenoxazinone synthase-like activity of the complex have been studied; the turnover numbers (kcat) for these oxidase reactions have been calculated to be 126.9 and 738.0 h-1, respectively. © 2018 The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.