Proton-Conductive Coordination Polymers Based on Diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylate with Well-Defined Hydrogen Bonding Networks.

The diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylic acid (H-DPSDSDC) ligand and its coordination polymers, [KZn(CHSO)(HO)] () and {[Cu(μ-OH)(CHSO)(HO)(DMF)]·3(HO)} () (CHSO = diphenylsulfone-3,3'-disulfo-4,4'-dicarboxylate), were synthesized. The Zn(HO) units in are connected by DPSDSDC ligands to generate a one-dimensional (1D) chain, which is bridged by K-O bonds associated with bridging water molecules and sulfonate groups to yield a two-dimensional (2D) layer. In , the 1D hydroxyl-bridging Cu(II) chains are connected by DPSDSDC ligands to give a 2D layer. The 2D layers in and are further connected by interlayered hydrogen bonds to give three-dimensional (3D) frameworks. Compounds and have good conductivities of 1.57 × 10 and 5.32 × 10 S cm, respectively. Continuous well-defined hydrogen bonding networks associated with water molecules, sulfonate groups, and carboxylate groups were observed in compounds and . Such hydrogen bonding networks provide hydrophilic domains and effective transfer pathways for protons. Here, we present elegant examples of a precise determination of the pathways for proton transport.