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The exploitation of excited state chemistry for solar energy conversion or photocatalysis has been continuously increasing, and the needs of a transition to a sustainable human development indicate this trend will continue. In this scenario, the study of mixed valence systems in the excited state offers a unique opportunity to explore excited state electron transfer reactivity, and, in a broader sense, excited state chemistry. This Concept article analyzes recent contributions in the field of photoinduced mixed valence systems, i. e. those where the mixed valence core is absent in the ground state but created upon light absorption. The focus is on the utilization of photoinduced intervalence charge transfer bands, detected via transient absorption spectroscopy, as key tools to study fundamental phenomena like donor/acceptor inversion, hole delocalization, coexistence of excited states and excited state nature, together with applications in molecular electronics.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9805035 | PMC |
http://dx.doi.org/10.1002/cphc.202200384 | DOI Listing |
Chemistry
September 2025
Department of Chemistry and the Manitoba Institute for Materials, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada.
The coordination chemistry of the planar, doubly π-extended bipyridine analog, 6,6',7,7'-biphenanthridine (p-biphe), is presented. The phenanthridine units in p-biphe are fused together at the 6- and 7- positions, and the resulting rigid ligand is compared with the more flexible parent "biphe" fused only at the 6-positions. p-Biphe is intensely fluorescent in solution with a much higher quantum yield, but, unlike biphe, at 77 K the fluorescence is not accompanied by any significant phosphorescence.
View Article and Find Full Text PDFChemistry
September 2025
Julius-Maximilians-Universität Würzburg, Institut für Organische Chemie, Würzburg, 97074, Germany.
Photosensitization has emerged as a versatile tool to facilitate access to excited states under mild conditions, allowing for efficient and selective photochemical transformations. Herein, we report a very simple molecule, coronene bisimide (CBI), as a potent visible-light photosensitizer featuring a high extinction coefficient with a broadband absorption spanning from ultraviolet to green region of the visible spectrum, along with a long-lived triplet state generated via efficient intersystem crossing (ISC). Utilizing the triplet-triplet energy transfer (TTEnT) strategy, CBI catalyzes diverse reactions under green light irradiation.
View Article and Find Full Text PDFACS Appl Mater Interfaces
September 2025
College of Engineering and Applied Sciences, Nanjing University, Nanjing 210093, P. R. China.
Exhaled breath analysis offers noninvasive, early lung cancer detection via volatile organic compound (VOC) biomarkers, surpassing blood-based methods. Surface-enhanced Raman spectroscopy (SERS) is ideal for this purpose, combining molecular fingerprint specificity with single-molecule sensitivity. However, conventional SERS substrates face a fundamental limitation: while porous materials such as metal-organic frameworks effectively adsorb VOCs through their subnanometer pores (0.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
Ionization of alkanes to form radical cations activates their otherwise unreactive C-H bonds, facilitating important chemical processes such as hydrocarbon cracking. This work investigates the radical cation dissociation dynamics of hexane (CH) structural isomers by using femtosecond time-resolved mass spectrometry and quantum chemical calculations. All five isomers exhibit competition between the yields of fragment ions arising from direct C-C bond cleavage or dissociative rearrangement with hydrogen migration on dynamical time scales of ∼50-300 fs, suggesting that hydrogen migration in the metastable cations operates on such short time scales.
View Article and Find Full Text PDFAnal Chim Acta
November 2025
Key Laboratory of Analytical Science and Technology of Hebei Province, College of Chemistry and Materials Science, Hebei University, Baoding, 071002, PR China; Engineering Research Center of Ecological Safety and Conservation in Beijing-Tianjin-Hebei (Xiong'an New Area) of Ministry of Education, Bao
Background: In the contemporary era of rapid digital advancement, information security is closely associated with our daily life. From personal information to state secrets, all domains are intricately linked with information. Consequently, the significance of information security has garnered growing attention from an ever-increasing number of individuals.
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