A broad perspective on metal complex-based optical recognition of fluoride ions: Twelve years (2014-2025) of innovations and applications

Abstract

The fluoride ion (F -) is one of the most important anions because of its usefulness in the maintaining of oral health and bonegrowth, and existence in a variety of clinical, environmental, and food samples. The U.S. Public Health Service recommends a [F -] of 0.7 mg L -1 as the optimal level for the prevention of dental caries in drinking water. Excessive F -exposure for long time causes dental and skeletal fluorosis, joint stiffness, interfere with thyroid hormone production, kidney problem and reproductive issues. Therefore, there is a need for analytical and practical techniques for the selective, sensitive, fast trace detection and quantification of fluoride ion in food, drinks and beverages. The photophysical properties of the metal complexes have been widely exploited in the design of chemosensors for F -ion detection. During the recent past, many metal-complex-based probes have been recognized in the reports, and they are assumed to be promising for the progress of efficient, selective, and sensitive methods for fluoride ion recognition. To the best of our knowledge, several reviews have been written so far, but the majority of them concentrate on organic small molecular chemosensors and some selective metal-based receptors for F -detection but there are hardly any report exists that systematically summarised metal-complex and coordination polymeric frameworks-based receptors for F -ion recognition. This review provides an overview of recent advances in the development of metal-complex-based receptors, including metal-organic frameworks, for selective recognition of fluoride since the last couple of years (2014-2025). This review will particularly address the design concepts, structural features, mechanism of action, recognition efficiency, sensitivity, selectivity, and practical uses of metal-based receptors in fluoride sensing