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.