Water-mediated proton conduction in two stable fluorophenyl imidazole dicarboxylate-based cadmium(II) complexes

Recently, crystalline solid materials as proton conductors have attracted intensive attention. Herein, two highly stable complexes, 2D coordination polymer [Cd(3,5-DFPhH2IDC)(2)]center dot H2O (1) and supramolecule [Cd(3,5-DFPhH2IDC)(2)(phen)(H2O)]center dot 0.5H(2)O (2) (phen = 1,10-phenanthroline), have been synthesized by using 2-(3,5-difluorophenyl)imidazole-4,5-dicarboxylic acid (3,5-DFPhH3IDC) as organic ligand. The water-assisted proton-conductive properties of 1 and 2 were investigated by impedance spectroscopy. Notably, the proton conductivity of both complexes attains the optimized value of 4.90 x 10(-5) S cm(-1) for 1 and 2.04 x 10(-4) S cm(-1) for 2 under 100 degrees C and 98% RH. Consequently, their proton-conducting mechanisms based on the E-a values were highlighted. [GRAPHICS] .