Three Polyoxovanadoborates Constructed from “Sandwich”-Type {V10B24}, {V10B28}, and {V12B32} Clusters

Three distinct polyoxovanadoborates modified by transition metals, specifically {V10B26Cd8(phen)12} (1, phen = 1,10-phenanthroline), {V10B32Zn6} (2), and {V12B32Cu2} (3), have been synthesized under hydrothermal conditions. Compounds 1-3 feature three unique sandwich-type clusters, namely, {V10B24}, {V10B28}, and {V12B32}, each characterized by toroidal (O═VO2)n (n = 10, 12) rings. In the structure of 1, two pairs of {Cd(phen)} and {Cd(phen)2} units are grafted on the {B13} rings from the top and bottom of the {V10B24} cluster, respectively. Compound 2 is a 1D polymeric chain consisting of the bridging ligand {ZnO6} unit linked to {V10B28}, which accommodates the {Zn4B4O8} unit. The {V12B32} cluster in 3 is interconnected with [Cu(en)2]2+ (en = ethylenediamine) to create the sql layer, which is further stacked in an ABAB sequence to form a 3D supramolecular framework. Additionally, sulfide catalytic oxidation experiments revealed that compound 2 is an efficient and stable sulfide oxidation catalyst.