Preparation, structures and properties of manganese complexes containing amine-(amido or amidato)-phenolato type ligands

Complexation of 2-hydroxy-N-(n-aminoalkyl)benzamides, where n-aminoalkyl substituents are 2-amino-2-methylpropyl (H(2)L2(Me2)), (R)-2-aminopropyl {(R)-H(2)L2(Me)} and 3-aminopropyl (H(2)L3), with manganese(II)chloride or perchlorate were examined. With the 2-aminopropyl derivatives, dinuclear methoxido-bridged manganese(III) complexes bearing the dianionic ligands, [{Mn(L2(Me2) or (R)-L2(Me)) (MeOH)}(2)(mu-OMe)(2)] (2 or 4), were isolated and their crystal structures were determined. There was a weak antiferromagnetic interaction between two axially distorted Mn-III centers in 2. Also, with the ligand of (L2(Me2))(2) a mononuclear manganese(IV)complex, [Mn(L2(Me2))(2)]center dot DMF (3 center dot DMF) was obtained. In the crystal of 3 center dot DMF a heterochiral dimerization via the intermolecular double hydrogen-bonds was observed. In the case of reactions with H(2)L3, mononuclear manganese(III)complexes, [Mn(H(2)L3 ')(2)Cl-2] Cl (6)and [Mn(H(2)L3 ')(2)(MeOH)(2)]Cl-2(ClO4)(7), were afforded, where the ligand (H(2)L3 ')has a phenolateamide-ammonium type zwitterionic form of H(2)L3 and coordinates to a Mn-III center via the phenolato-O and amide-O atoms to form a six-membered chelate ring. Furthermore, a tetranuclear (Mn2Mn2III)-Mn-II double incomplete-cubane type cluster compound, [Mn-4(HL3)(2)Cl-2(OMe)(6)(MeOH)(2)]center dot 4MeOH (5a center dot 4MeOH) was revealed by the single-crystal X-ray diffraction study, although the bulk crystals (5)obtained from the reaction mixture showed a different PXRD pattern. The elemental analysis of the bulk crystals of 5 suggested that they consist of the same tetranuclear clusters. It is interesting that the bulk crystals of 5 were highly efflorescent, and it was suggested that their coordinated MeO and MeOH ligands were easily substituted by OH and H2O, respectively, in atmospheric air. This conversion changed their magnetic behaviors drastically. (C) 2016 Elsevier B.V. All rights reserved.