Dodecanuclear Manganese(III) Phosphonates with Cage Structures

Treatments of Mn(O2CR)2 (R = Me, Ph) with NBu4MnO4 in CH3CN or CH3CN/CH2Cl2 in the presence of acetic acid, δ1-cyclohexenephosphonic acid (C6H9PO3H2), and 2,2‘-bipyridine or 1,10-phenanthroline result in three novel dodecamanganese(III) clusters [Mn12O8(O2CMe)6(O3PC6H9)7(bipy)3] (1), [Mn12O8(O2CPh)6(O3PC6H9)7(bipy)3] (2), and [Mn12O8(O2CPh)6(O3PC6H9)7(phen)3] (3). They have a similar Mn12 core of [MnIII12(μ4-O)3(μ3-O)5(μ-O3P)3] with a new type of topologic structure. Solid-state dc magnetic susceptibility measurements of complexes 1−3 reveal that dominant antiferromagnetic interactions are propagated between the magnetic centers. The ac magnetic measurements suggest an S = 2 ground state for compounds 1 and 3 and an S = 3 ground state for compound 2.