Abstract
Two types of isostructural iron-cobalt/nickel-antimony-oxo tartrate cluster-based compounds, namely (H(3)O)(Me(2)NH(2))[M(H(2)O)(6)](2)[Fe(II)(2)Sb(III)(12)(μ(4)-O)(3)(μ(3)-O)(8)(tta)(6)]·6H(2)O (M = Co (1); Ni (3)), H(5/3)[Co(2.5)Fe(II)(4/3)Fe(III)(3)(H(2)O)(13)Sb(V)(1/3)Fe(III)(2/3)(μ(4)-O)(2)(μ(3)-O)(4)Sb(III)(6)(μ(3)-O)(2)(tta)(6)]·2H(2)O (2) and H(2)[Ni(2.25)Fe(II)(1.5)Fe(III)(3)(H(2)O)(14)Sb(V)(0.25)Fe(III)(0.75)(μ(4)-O)(2)(μ(3)-O)(4)Sb(III)(6)(μ(3)-O)(2)(tta)(6)]·2H(2)O (4) (H(4)tta = tartaric acid) were synthesized via simple solvothermal reactions. All the clusters in the structures adopt sandwich configurations, that is, bilayer sandwich configuration in 1 and 3 and monolayer sandwich configuration in 2 and 4. Interestingly, the monolayer sandwiched compounds 2 and 4 represent rare examples of cluster-based compounds containing mixed-valence Sb(III, V), whose center of the intermediate layer is the co-occupied [Fe(x)Sb(V)(1-x)]. This is different from that of previously reported sandwich-type antimony-oxo clusters in which the center position is either occupied by a transition metal ion or a Sb(V) alone. Thus, the discovery of title compounds 2 and 4 makes the evolution of center metal ion more complete, that is, from M, M(x)Sb(V)(1-x) to Sb(V). All the title compounds were fully characterized, and the photocatalysis, proton conduction and magnetism of compounds 2 and 4 were studied.