Composite host lattices of 4,4'-sulfonyldibenzoate water/boric acid in two tetrapropylammonium inclusion compounds

Two novel inclusion compounds of 4,4'-sulfonyldibenzoate anions and tetrapropylammonium cations with different ancillary molecules of water and boric acid, namely bis(tetrapropylammonium) 4,4'-sulfonyldibenzoate dihydrate, 2C₁₂H₂₈N⁺·C₁₄H₈O₆S^2-·H₂O (1), and bis(tetrapropylammonium) 4,4'-sulfonyldibenzoate bis(boric acid), 2C₁₂H₂₈N⁺·C₁₄H₈O₆S^2-·2H₃BO₃ (2), were prepared and characterized using single-crystal X-ray diffraction. In the two salts, the host 4,4'-sulfonyldibenzoic acid molecules, which are converted to the corresponding anions under basic conditions, can be regarded as proton acceptors which link different proton donors of the ancillary molecules of water or boric acid. In this way, an isolated hydrogen-bonded tetramer is constructed in salt 1 and a ribbon is constructed in salt 2. The tetramers and ribbons are then packed in a repeating manner to generate various host frameworks, and the tetrapropylammonium guest counter-ions are contained in the cavities of the host lattices to give the final stable crystal structures. In these two salts, although the host anion and guest cation are the same, the difference in the ancillary small molecules results in different structures, indicating the significance of ancillary molecules in the formation of crystal structures.