Linear trinuclear mixed valance Mn-III-Mn-II-Mn-III complex: Synthesis, crystal structure and characterization

A new linear trinuclear Mn-III-Mn-II-Mn-III complex 1 has been synthesized and characterized by elemental, spectral, X-ray and magnetic analysis. X-ray diffraction studies show that the central Mn-II ion is located at a crystallographic inversion center and is triply bridged to the terminal Mn-III ions through one methoxide, one syn-syn carboxylate and one hydroxyl oxygen bridges with the short Mn-III center dot center dot center dot Mn-II distance that is 3.047 angstrom. The intermolecular C-H center dot center dot center dot O, C-H center dot center dot center dot pi and ring-metal interactions are observed in the hydrogen-bonded assembly of 1. Magnetic studies reveal that themixed-valence complex 1 has S = 3/2 ground state with antiferromagnetic exchange interactions between Mn-II and Mn-III ions.