Dual-Ligand-Regulated Tb-Containing Antimonotungstate for the Heterogeneous Catalytic Synthesis of N-Heterocycles in Ethanol.

A novel Tb-containing antimonotungstate, [(CH)NH]Na[Tb(mal)(OAc)(WO)(SbWO)(HO)]·47HO, regulated by dl-malic acid and acetic acid (, Hmal = malic acid; HOAc = acetic acid), has been successfully synthesized. The structural analysis reveals that the polyanion of consists of four {B-α-SbWO} units interconnected by a decanuclear metal cluster {TbW(mal)(OAc)}. The flexible malic acid ligands involved in the coordinating process create a certain torsion angle, resulting in a twisted rectangular structure of polyanion . In addition, exhibits excellent heterogeneous catalytic activity for the synthesis of 3,4-dihydro-2-1,2,4-benzothiadiazine-1,1-dioxides through the condensation reaction of 2-aminobenzenesulfonamide and benzaldehydes under environmentally benign reaction conditions.