The sensing mechanism studies of the fluorescent probes with electronically excited state calculations

Recent research has indicated that fluorescent probes have tremendous potential for the selective detection of chemical and biological species. Over the past decade, researchers have proposed a series of fluorescence‐based sensing mechanisms of such probes by the calculation of their electronic excited states. Investigations of sensing mechanisms have been based on deep insights into the interactions between probe molecules and their target species, as well as their fluorescence properties. Advances in calculation methods, modeling software, and computational power have enabled researchers to use excited‐state theoretical calculations to reproduce experimental fluorescence phenomena and then provide molecular‐level explanations thereof. In this advanced review, we describe the evolution of theoretical studies on excited‐state sensing mechanisms for fluorescent probes that respond to target species. Focusing on calculation methods that facilitate investigation of the photophysical properties and excited‐state dynamics of probes, we emphasize sensing mechanisms mainly reported by our group. Most of these studies have been supported by theoretical predictions based on time‐dependent density functional theory. For this most popular excited‐state calculation method, vertical excitation energy, excited‐state geometrical optimization and a scan of the excited‐state potential energy surface should be noted in the calculation of electronic and molecular differences between the excited‐state probe and its reaction product with the target analyte. These state‐of‐the‐art calculations are of great importance for unraveling details of fluorescence‐based sensing mechanisms, including photochemical reactions (such as twist intramolecular charge transfer and excited‐state proton transfer) and excited‐state electronic processes (such as intramolecular charge transfer and photoinduced electron transfer). These studies have generated new and inspirational mechanistic proposals and have provided a systematic approach for the development of efficient fluorescent sensors. WIREs Comput Mol Sci 2018, 8:e1351. doi: 10.1002/wcms.1351 This article is categorized under: Structure and Mechanism > Computational Biochemistry and Biophysics Theoretical and Physical Chemistry > Spectroscopy