High nuclearity manganese(III) compounds containing phenol-pyrazole ligands: the influence of the ligand on the core geometry

Three high-nuclearity manganese(III) clusters have been synthesized and characterized: [Mn(8)(mu(4)-O)(4)(phpzH)(8)(thf)(4)] (1), [Mn(8)(mu(4)-O)(4)(phpzH)(4)(EtOH)(4)]center dot 2EtOH (2), and [Mn(6)(mu(3)-O)(4)(mu(3)-Br)(2)(HphpzEt)(6)(phpzEt)] (3). Compounds 1 and 2 contain a [Mn(8)(mu(4)-O(4))(phpzH)(8)] core in which antiferromagnetic interactions between the manganese(III) ions are found. Compound 3 is a hexanuclear manganese(III) cluster in which weak ferromagnetic interactions appear to be operative. The formation and the stability of the cluster cores in relation to the type of phenol-pyrazole ligand and the reaction conditions are discussed.