A triazole-bearing picket fence type nickel porphyrin as a cyanide selective allosteric host.

A triazole-bearing picket fence type nickel porphyrin (1) has been synthesized as a host compound for anion binding. Among the various anionic species examined, cyanide was the only one that affected a spectral change of 1. Moreover, 1 exhibited strong homotropic positive allosterism against cyanide binding due to an electronic effect as well as multiple hydrogen bonds formed between cyanide and the triazole groups.