Fluorescent probes for mercury ion based on small molecules

As one of the most toxic heavy metals, mercury ion causes severe environmental and healthy problems. Hence, its sensing methods have been widely studied. Due to their unique advantages, such as high sensitivity, low cost and fast detection, fluorescent probes have been one of the most important sensing methods for mercury ion. The mercury ion could be coordinated with specific receptors of fluorescent probes. Such complexation causes the changes of photophysical properties and realizes highly selective mercury ion detection. Herein, fluorescent probes for mercury ion based on small molecules reported in recent years have been reviewed. The design principles of probe materials, as well as their sensing mechanisms and applications are summarized. The structure-property relationships are also elucidated. Finally, the development and prospect are foreseen in the field of mercury ion probes.