Mixed valence manganese-( II , III ) and -( III , IV ) dinuclear complexes: preparation, structure, magnetochemistry, and e.s.r. spectra of Mn 2 (biphen) 2 (biphenH)(bpy) 2 and Mn 2 O 2 Cl 2 (OAc)(bpy) 2 (biphenH 2 = 2,2′-biphenol, bpy = 2,2′-bipyridine)

The preparation and properties of two new mixed valence Mn complexes, Mn2(biphen)2(biphenH)(bpy)2(3) and Mn2O2Cl2(OAc)(bpy)2(2)(bpy = 2,2′-bipyridine, biphenH2= 2,2′-biphenol) are reported; complex (3) has a rare S= 9/2 ground state confirmed by magnetization studies.