Cobalt metal-mixed organic complex-based hybrid micromaterials: ratiometric detection of cyanide

A micrometer-sized hybrid crystalline material was facilely fabricated from the synergistic coordination chemistry of two types of 2-hydroxyazobenzene building blocks and cobalt ions. This hybrid crystalline material functioned as both receptor and signal reporter in cyanide (CN(−)) sensing with ratiometric absorption responses at 456 nm and 537 nm. The mechanism of CN(−) sensing involves partial ligand dissociation accompanied by the formation of a new organic metal–CN(−) adduct. We believe that this protocol would be valuable in achieving the expected selectivities and sensitivities for a wide variety of analytes in many chemical and biological systems in the future.