Excited state intramolecular proton transfer (ESIPT) has been documented from an amino NH group to a carbon atom of an adjacent aromatic ring. This finding changes the paradigm, as hitherto such processes have not been considered as plausible due to slow protonation of carbon and low (photo)acidity of the NH group. The ESIPT was studied by irradiation of 2-(2-aminophenyl)naphthalene in CHCN-DO, whereupon regiospecific incorporation of deuterium takes place at the naphthalene position 1, with a quantum yield of Φ = 0.11. A synergy of experimental and computational investigations completely unraveled the mechanism of this important photochemical reaction. Upon excitation to the photoreactive S(L) state, a favorable redistribution of charge sets the stage for ESIPT to the carbon atom in naphthalene position 1. HO molecules are needed, as they increase the excitation energy and oscillator strength for the population of the S(L) state. The gain in energy is used to surmount a small energy barrier on the pathway from the Franck-Condon geometry to the conical intersection with the S, delivering aza-quinone methide.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/acs.joc.2c00818 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Application of a New Thermal Model for the Determination of London Dispersive Properties of H-β-Zeolite/Rhodium Catalysts Using New 2D Chromatographic Models.
Materials (Basel)
December 2024
Faculty of Science and Engineering, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
A new methodology based on the Hamieh thermal model was applied for the determination of the surface properties of solid surfaces. The new approach consisted of the accurate quantification of the London dispersive surface energy of materials using the two-dimensional inverse gas chromatography technique at infinite dilution. This technique used the notion of the net retention volume of adsorbed molecules on the solid catalysts, allowing the determination of the free energy of adsorption.
View Article and Find Full Text PDFRepresenting Structural Isomer Effects in a Coarse-Grain Model of Poly(Ether Ketone Ketone).
Polymers (Basel)
January 2025
Micron School of Material Science and Engineering, Boise State University, Boise, ID 83725, USA.
Carbon-fiber composites with thermoplastic matrices offer many processing and performance benefits in aerospace applications, but the long relaxation times of polymers make it difficult to predict how the structure of the matrix depends on its chemistry and how it was processed. Coarse-grained models of polymers can enable access to these long-time dynamics, but can have limited applicability outside the systems and state points that they are validated against. Here we develop and validate a minimal coarse-grained model of the aerospace thermoplastic poly(etherketoneketone) (PEKK).
View Article and Find Full Text PDFMicrobe-mediated synthesis of defect-rich CeO nanoparticles with oxidase-like activity for colorimetric detection of L-penicillamine and glutathione.
Nanoscale
January 2025
College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, P.R. China.
To enhance production efficiency, curtail costs, and minimize environmental impact, developing simple and sustainable nanozyme synthesis methods has been the focus of relevant research. In this report, graphite-coated CeO nanoparticles (CeO NPs) with multiple defects (Ce defects, oxygen vacancies and carbon defects) were synthesized the culture filtrate of the extremely radioresistant bacterium R12 ( R12). The as-prepared CeO NPs exhibit remarkable oxidase (OXD)-like activity, efficiently catalyzing the oxidation of the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB) to form oxTMB, even in the absence of HO.
View Article and Find Full Text PDFNonprecious Triple-Atom Catalysts with Ultrahigh Activity for Electrochemical Reduction of Nitrate to Ammonia: A DFT Screening.
ACS Appl Mater Interfaces
January 2025
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR 999077, China.
Electrochemical nitrate reduction to ammonia (NORR) is promising to not only tackle environmental issues caused by nitrate but also produce ammonia at room temperatures. However, two critical challenges are the lack of effective electrocatalysts and the understanding of related reaction mechanisms. To overcome these challenges, we employed first-principles calculations to thoroughly study the performance and mechanisms of triple-atom catalysts (TACs) composed of transition metals (including 27 homonuclear TACs and 4 non-noble bimetallic TACs) anchored on N-doped carbon (NC).
View Article and Find Full Text PDFLaser Synthesis of Platinum Single-Atom Catalysts for Hydrogen Evolution Reaction.
Nanomaterials (Basel)
January 2025
Department of Materials, School of Natural Science, The University of Manchester, Oxford Road, Manchester M13 9PL, UK.
Platinum (Pt)-based heterogeneous catalysts show excellent performance for the electrocatalytic hydrogen evolution reaction (HER); however, the high cost and earth paucity of Pt means that efforts are being directed to reducing Pt usage, whilst maximizing catalytic efficiency. In this work, a two-step laser annealing process was employed to synthesize Pt single-atom catalysts (SACs) on a MOF-derived carbon substrate. The laser irradiation of a metal-organic framework (MOF) film (ZIF67@ZIF8 composite) by rapid scanning of a ns pulsed infrared (IR; 1064 nm) laser across the freeze-dried MOF resulted in a metal-loaded graphitized film.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!