Towards Nanoscopic Mn-Containing Hybrid Polyoxomolybdates: Synthesis, Structure, Magnetic Properties, and Solution Behavior of a {Mn6Mo10} Cluster


  • Dedicated to Professor Michael T. Pope on the occasion of his 80th birthday


A manganese-containing organic–inorganic hybrid polyoxomolybdate, (TBA)2[MnII6MoVI10(O)12(μ-O)143-O)4(tert-butyl-PO3)6(Ac)2(pyridine)4(H2O)6]·(CH3CN)6 (1; Ac = CH3COO, TBA = tetrabutylammonium), was synthesized and characterized by single-crystal X-ray diffraction, elemental analysis, and IR spectroscopy. Lindqvist hexamolybdate and manganese(III) acetylacetonate were used as starting Mo and Mn sources, respectively. Hexadecanuclear, mixed-metal 1 is characterized by a sandwich-type structural motif, whereby a central {Mn6} unit is capped by two {Mo5} moieties. In addition, six fully deprotonated tert-butylphosphonate ligands bridge these metal centers by adopting η1124 binding modes. MALDI-MS studies demonstrated that 1 displays interesting fragmentation behavior involving a series of {Mn6Mo10}, {Mn6Mo9}, {Mn6Mo8}, {Mn6Mo7}, {Mn6Mo6}, {Mn6Mo5}, and {Mn6Mo4} moieties. Investigation of the magnetic properties of 1 highlights typical antiferromagnetic interactions between the MnII spin centers.