Dual-Functional Coordination Polymer with High Proton Conductivity and a Low-Detection-Limit Fluorescent Probe

A coordination polymer with dual functions of high proton conductivity and highly sensitive fluorescent sensors demonstrates a great application potential. In this work, a cadmium-based coordination polymer (denoted as CP ) with hydrothermal stability was synthesized. The abundant coordination water, lattice water, and amino groups make an extended hydrogen-bonding pathway for efficient proton migration, which endows CP with the highest proton conductivity of 2.41 × 10 S·cm at 353 K and 98% RH. Especially, the proton conductivity of the chitosan (CS) hybrid membrane containing CP reaches a maximum value of 2.62 × 10 S·cm under 343 K and 98% RH, which increases almost 7 times higher than that of the pure CS membrane due to the host-guest collaboration. Furthermore, luminescence studies revealed that CP is a high-sensitivity and good-selectivity fluorescent probe for the detection of trace amounts of l-histidine with a lowest detection limit of 1.0 × 10 M.