Mixed-valent tetranuclear manganese complexes with an {MnII3MnIV} core

Two new examples of mixed-valent phenyl 2-pyridyl ketoxime complexes with an {MnII3MnIV-μ4-O} core are presented: cationic {MnII3MnIVO(OH)[Ph(py)CNO]3[Ph(py)CNOH](ClC6H4COO)3}+ (1) and neutral {MnII3MnIVO[Ph(py)CNO]4(IC6H4COO)4} (2), representing two different structural types (types I and II, respectively). Also preliminary data are mentioned for two further complexes with (2-pyrimidylthio)acetate (3) or 2-(methylthio)nicotinate (4) ligands. 1 and 2 differ in magnetic properties, 1 representing the first {MnII3MnIV-μ4-O}-core cationic complex with dominating antiferromagnetic interactions.