Synthesis, characterization and magnetic properties of mono- and dinuclear complexes of Manganese (III) and (IV) supported by (E)- N ′-(1-(thiophene-2-yl)ethylidene)benzohydrazide arising from an unusual Mn(III) to Mn(IV) disproportionation reaction

A new MnIV dinuclear complex [MnIV2(μ-O)2(L′)4].2CH3OH (HL′=(E)-N′-(1-(thiophen-2-yl)ethylidene)benzohydrazide) was obtained from MnIII(acetate)3.2H2O by an unusual MnIII disproportionation reaction. This compound exhibits a strong antiferromagnetic coupling with a J value of −149(5) cm−1. Moreover, a new MnIII mononuclear complex bearing L′ named [MnIII(acac)(L′)2] (acac = acetylacetonate) was obtained from [MnIII(acac)3] and is described as a part of a systematic research work around manganese complexes of magnetic interest.