Synthesis and structural and magnetic characterization of a hexadecanuclear cobalt phosphonate compound

摘要

A wheel-like hexadecanuclear cobalt phosphonate [Co_(16)(OH) _6(chp)_(22)(O_3PC_6H_9) _2(H_2O)_4] has been synthesized by reactions of cobalt perchlorate with cyclohexenephosphonic acid (H_2O _3PC_6H_9) and 6-chloro-2-hydroxypyridine (Hchp) in the presence of Et_3N. Magnetic studies on the compound show a general decline of χ_MT with decreasing T. The appeared maximum of χ_MT at low temperature suggests the presence of a non-diamagnetic ground state. The alternating current susceptibilities show frequency-dependent signals.