Terpyridine-Based Fluorescent Sensors: Investigating the Analytical Properties for Diverse Applications

The research area involving fluorescent probes have gained attention in recent years due to their multiple advantages including ease of visualization, simplicity of use, instant biological imaging, and cost-effectiveness. Several fluorescent cores are available that can be used to design fluorescent sensors for various applications. Terpyridine is a core that has been widely synthesized involving carbon–carbon coupling reactions or by central ring assembly. The lateral phenyl (4′-phenyl) position of terpyridine can be functionalized easily by incorporation of additional organic functionalities that makes terpyridine more advantageous and highly explored fluorescent core. The emission wavelength of terpyridine can be tuned on substitution of electron withdrawing or donating functionalities. Terpyridine based probes has been reported for their use in environmental application, such as sensing of cation and anion, nerve agent in water, food, milk, cell imaging and disease diagnosis, etc. In this review we have compiled the recent developments in terpyridine based sensors that can be utilized for biological and non-biological applications. The mechanism of sensing along with the limit of detection and photophysical parameters of terpyridine based sensors have been discussed. The applications ranging from cell imaging, sensing of pH, detection of citrate, oxygen, H2S, nitro aromatic compounds, sulfonamide antibiotics, vitamin C, single oxygen, and radioactive metals, such as uranium in variety of sample matrix is covered in this review. In this review we have incorporated the most common synthetic methods for synthesis of terpyridine core using the cross-coupling reaction and central ring assembly.