Solvothermal Synthesis, Structural Diversity, and Properties of Alkali Metal–Organic Frameworks Based on V‑shaped Ligand

A series of four new metal–organic frameworks, [Na₂(SBA)] (1 or CYCU-6), [K₈(H₂O)₂(SBA)₄(DMF)] (2), [Rb₂(SBA)] (3), and [Cs­(H₂O)­(HSBA)]·DMF (4), have been constructed under solvothermal conditions by using 4,4′-sulfonyldibenzoic acid (H₂SBA) as ligand. The structure of the complexes has been determined by single-crystal X-ray diffraction analysis and further characterized by elemental analyses, reflectance UV–vis, and IR spectra, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). The single crystal X-ray structural studies showed that all the complexes display three-dimensional (3D) structures containing inorganic motifs with one-dimensional chains connected through organic linkers and forming 3D networks. Among the four complexes, the Na­(I) complex (1) displays very high thermal stability, which was inferred from TGA and PXRD results. Moreover, the solid state luminescent properties of the new complexes have been investigated at room temperature. In addition, the gas sorption properties of 1 toward nitrogen, hydrogen, carbon dioxide, and methane are reported.