Synthetic Entry into Polynuclear Bismuth–Manganese Chemistry: High Oxidation State BiIII2MnIV6 and BiIIIMnIII10 Complexes

The first high nuclearity, mixed-metal BiIII/MnIV and BiIII/MnIII complexes are reported. The former complexes are [Bi2MnIV6O9(O2CEt)9(HO2CEt)(NO3)3] (1) and [Bi2MnIV6O9(O2CPh)9(HO2CPh)(NO3)3] (2) and were obtained from the comproportionation reaction between Mn(O2CR)2 and MnO4– in a 10:3 ratio in the presence of Bi(NO3)3 (3 equiv) in either a H2O/EtCO2H (1) or MeCN/PhCO2H (2) solvent medium. The same reaction that gives 2, but with Bi(O2CMe)3 and MeNO2 in place of Bi(NO3)3 and MeCN, gave the lower oxidation state product [BiMnIII10O8(O2CPh)17(HO2CPh)(H2O)] (3). Complexes 1 and 2 are near-isostructural and possess an unusual and high symmetry core topology consisting of a MnIV6 wheel with two central BiIII atoms capping the wheel on each side. In contrast, the [BiMnIII10O8]17+ core of 3 is low symmetry, comprising a [BiMn3(μ3-O)2]8+ butterfly unit, four [BiMn3(μ4-O)]10+ tetrahedra, and two [BiMn2(μ3-O)]7+ triangles all fused together by sharing common Mn and Bi vertices. Variable-temperature, solid-state dc and ac magnetization data on 1–3 in the 1.8–300 K range revealed that 1 and 2 possess an S = 0 ground state spin, whereas 3 possesses an S = 2 ground state. The work offers the possibility of access to molecular analogs of the multifunctional Bi/Mn/O solids that are of such great interest in materials science.