Lanthanide-Potassium Biphenyl-3,3'-disulfonyl-4,4'-dicarboxylate Frameworks: Gas Sorption, Proton Conductivity, and Luminescent Sensing of Metal Ions.

A novel sulfonate–carboxylate ligand of biphenyl-3,3′-disulfonyl-4,4′-dicarboxylic acid (H4–BPDSDC) and its lanthanide–organic frameworks {[LnK(BPDSDC)(DMF)(H2O)]·x(solvent)}n (JXNU-2, where JXNU denotes Jiangxi Normal University, DMF indicates dimethylformamide, and Ln = Sm3+, Eu3+, and Pr3+) were synthesized and structurally characterized. The three isomorphous lanthanide compounds feature three-dimensional frameworks constructed from one-dimensional (1D) rod-shaped heterometallic Ln–K secondary building units and are an illustration of a Kagome-like lattice with large 1D hexagonal channels and small 1D trigonal channels. The porous material of the representive JXNU-2(Sm) has an affinity to quadrupolar molecules such as CO2 and C2H2. In addition, the JXNU-2(Sm) compound exhibits humidity- and temperature-dependent proton conductivity with a large value of 1.11 × 10–3 S cm–1 at 80 °C and 98% relative humidity. The hydrophilic sulfonate group on the surface of channels facilitates enrichment of the solvat...