Theoretical Studies and Design Strategies of Highly Efficient Two-Photon Excited Fluorescent Probes for Hydrogen Sulfide Detection through Simulation of Excited-State Dynamics

Abstract

Hydrogen sulfide (H2S) plays a critical role in numerous physiological and pathological processes, but an abnormal level of H2S in living systems can cause various diseases. To detect the level of endogenous H2S in a complicated biological system, the luminous mechanism of “turn-on” probe for H2S monitoring has been deeply explored through the simulation of excited-state dynamic processes, and the effect of different geometric modifications on optical properties has been minutely investigated based on molecular modeling. TD-DFT calculations demonstrate that line-type π-expanding in the molecular skeleton is beneficial for improving two-photon absorption (TPA) ability, but it can give rise to extremely large geometric relaxation, going against fluorescence emission. It is an effective way to suppress molecular skeleton scissoring vibration by introducing strong electron-withdrawing substituent groups (F, Cl, Br, CN) in benzopyran, and these compounds also have superior TPA properties in NIR. One of the potential materials in the application of biological imaging and H2S detection has been obtained, which simultaneously possesses easily distinguished spectra (with a Stokes shift as large as 77 nm), high luminous efficiency (with a quantum yield up to 20.07%), and large TPA cross section (952 GM at 950 nm).

Photophysical Exploration of Alectinib and Rilpivirine: Insights from Theory and Experiment

“…Conversely, the smaller the non-radiative decay process, the larger of the . Internal conversion (IC), as a non-radiative decay from the first excited state to ground state, is the most important component during the non-radiative process [ 56 ]. The IC rate can be calculated under harmonic oscillator approximation though Fermi’s golden rule and is expressed as [ 57 ]: …”

Theoretical characterization of two-photon fluorescent probes for nitric oxide detection: sensing mechanism, photophysical properties and protonation effects

“…Γ is the spectral broadening factor (see part II in the ESI†) and is assumed to be 0.05 eV. 69 The common unit of σ tpa is Göppert–Mayer (GM), and 1 GM equals 10 −50 cm 4 s photon −1 .…”

Design, Synthesis and Evaluation of Fluorescent Properties of Benzothiazole Derivatives

“…Thus, alkyne group substitution at 3position of the thiazole ring led to the smaller transition orbital overlap and further reduced the oscillator strength of 11 A. [19] Compared with molecule 11 A (f: 0.6082), molecule 11 B following with amine group substituted in para-position of benzene ring had larger oscillator strengths (f: 0.9824) likely due to that the amine substitution in para-position enhanced the corresponding transition orbital overlap (see Figure S4).…”

“…[16][17][18] Furthermore, some potential fluorescent compounds, which were investigated by systemic theoretical investigation, need to be synthesized to verify the excellent optical properties. [19][20] Therefore, it is urged to develop more novel small molecular fluorescence compounds for various bioimaging applications by theoretical and experimental methods.…”