Hexa- and nonanuclear manganese clusters based on the chelating ligand 2-pyridinealdoxime

A hexanuclear Mn(II) complex [Mn6(Hpao)4(pao)8](ClO4)4 (1) and a nonanuclear mixed-valent Mn complex [Mn9(μ4–O)2(μ3–O)4(CH3CO2)4(pao)8(Hpao)2] · 4H2O (2) have been synthesized from the reaction of simple Mn(II) salts with syn-2-pyridinealdoxime (Hpao) in the presence of base. Structural characterization reveals in both cases the presence of protonated uncoordinated oxime functions, a topology solely held by oxime bridges in 1 and rare Mn(II)–Mn(III)–Mn(IV) mixed-valences in 2. Magnetic studies reveal a spin ground state of S = 0 for complex 1.