Modulating the excited-state intramolecular proton transfer (ESIPT) reaction to achieve anticipant performance is always fascinating for chemists. However, feasible methods and a definite mechanism for tuning the ESIPT reaction remain insufficient. In this work, we reported the feasibility of continuously modulating the ESIPT dynamics in 2-(2'-hydroxyphenyl)oxazole (HPO) derivatives with different substitutions on the positions 5 and 5' of the core HPO through steady-state/transient spectroscopy and theoretical calculations. We found that the main factor affecting the tendency of the ESIPT reaction is the variation of electron population on proton donor and acceptor. An index Δ was proposed to evaluate the overall promotion effect on proton transfer caused by the variation of electron population on proton donor and acceptor, which shows high reliability in interpreting the ESIPT tendency. This method, for its capacity to quickly estimate the tendency of ESIPT, shows great potential in ESIPT molecular design with chemical substitution of electron-donating/withdrawing moieties.
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http://dx.doi.org/10.1021/acs.jpclett.2c01025 | DOI Listing |
Langmuir
January 2025
National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, P. R. China.
To balance the stability and dissolution of polyacrylamide (PAM), emulsion drag reducers dominate the successful operation of volumetric fracturing. Herein, a pH-switchable four-tailed ionic liquid surfactant (OA/Cyclen) is synthesized by oleic acid (OA) and 1,4,7,10-tetraazacyclododecane (Cyclen). The four-tailed structure of OA/Cyclen enhances the stability of the emulsion polymerization reactor and supplies enough switchable sites for triggering the intensified release of the PAM emulsion.
View Article and Find Full Text PDFSensors (Basel)
December 2024
Institute of Autmatic Control, University of Kaiserslautern-Landau, 67653 Kaiserslautern, Germany.
Harsh operating conditions imposed by vehicular applications significantly limit the utilization of proton exchange membrane fuel cells (PEMFCs) in electric propulsion systems. Improper/poor management and supervision of rapidly varying current demands can lead to undesired electrochemical reactions and critical cell failures. Among other failures, flooding and catalytic degradation are failure mechanisms that directly impact the composition of the membrane electrode assembly and can cause irreversible cell performance deterioration.
View Article and Find Full Text PDFPolymers (Basel)
December 2024
Department of Organic and Polymer Chemistry, College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, China.
Stimulus-responsive luminescent materials are pivotal in the field of sensing. Fluorescent transition metal complexes with a charge transfer excited state, especially terpyridine-coordinated polymers, are of particular interest due to their tunable emission. In this paper, a novel bis-terpyridine ligand was synthesized and assembled into a coordination polymer, which showed intense visible light absorption and fluorescence emission in the solid state that could be regulated by an acidic or basic pH.
View Article and Find Full Text PDFMolecules
December 2024
Institute of Resources and Environmental Engineering, Shanxi University, Taiyuan 030032, China.
The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group dl-alanine to synthesise a water-soluble Al fluorescent probe (Probe A).
View Article and Find Full Text PDFMolecules
December 2024
Departamento de Química, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Ab initio calculations of cross sections for electron capture by protons in collisions with CO are carried out at energies between 100 eV/u and 50 keV/u, employing a semiclassical method within the Franck-Condon framework. The scattering wave function is expanded in a set of ab initio electronic wave functions of the HCO supermolecule. The calculation is performed on several trajectory orientations to obtain orientation-averaged total cross sections.
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