Single Organic Ligands Act as a Bifunctional Sensor for Subsequent Detection of Metal and Cyanide Ions, a Statistical Approach toward Coordination and Sensitivity

The detection of key ions in environmental samples has garnered significant attention in recent years in the pursuit of a cleaner environment for living organisms. Bifunctional and multifunctional sensors, as opposed to single-species sensors, have emerged as a rapidly developing field. Many reports in the literature have documented the use of bifunctional sensors for the subsequent detection of metal and cyanide ions. These sensors, consisting of simple organic ligands, form coordination compounds with transition metal ions, resulting in clear visible or fluorescent changes that facilitate detection. In some cases, a single polymeric material can act as a ligand and coordinate with metal ions, forming a complex that serves as a sensor for cyanide ion detection in biological and environmental samples through various mechanisms. Nitrogen is the most dominant coordinating site in these bifunctional sensors, with the sensitivity of the sensors being directly proportional to the denticities of ligands for metal ions, while for cyanide ions the sensitivity was found independent of the denticity of the ligands. This review covers the progress made in the field over the past fifteen years (2007-2022), with most ligands detecting copper (II) and cyanide ions, but with the capability to detect other metals such as iron, mercury, and cobalt as well.

Automated summary

The detection of key ions in environmental samples has become a significant focus in recent years for achieving a cleaner living environment. Bifunctional and multifunctional sensors have emerged as a rapidly advancing field, enabling the detection of metal and cyanide ions. These sensors, composed of simple organic ligands, form coordination compounds with transition metal ions, resulting in detectable visible or fluorescent changes. The sensitivity of these bifunctional sensors relies on the denticity of ligands for metal ions, while for cyanide ions, the sensitivity is independent of the denticity of ligands. This review summarizes the progress made in the field over the last fifteen years (2007-2022), with an emphasis on copper (II) and cyanide ion detection, but also the potential for detecting other metals such as iron, mercury, and cobalt.