The ability to manipulate excited-state decay cascades using molecular structure is essential to the application of abundant-metal photosensitizers and chromophores. Ligand design has yielded some spectacular results elongating charge-transfer excited state lifetimes of Fe(II) coordination complexes, but triplet metal-centered (MC) excited states─recently demonstrated to be critical to the photoactivity of isoelectronic Co(III) polypyridyls─have to date remained elusive, with temporally isolable examples limited to the picosecond regime. With this report, we show how strong-field donors and intramolecular π-stacking can conspire to stabilize a long-lived MC excited state for a remarkable 4.1 ± 0.3 ns in fluid solution at ambient temperature. Analysis of variable-temperature time-resolved absorption data using theoretical models ranging from Arrhenius to semiclassical Marcus theory, combined with computational modeling and X-ray crystallography, reveal a Jahn-Teller stabilized excited state with a high activation barrier for ground-state recovery. The net result is a chromophore with a MC excited-state lifetime that is orders of magnitude longer than anything yet observed for an Fe(II) complex.
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http://dx.doi.org/10.1021/jacs.4c12650 | DOI Listing |
J Voice
January 2025
Speech-Language Pathology Department, Universidade Federal de São Paulo - UNIFESP, Rua Botucatu, 802 Vila Clementino, 04023-062, São Paulo, São Paulo, Brazil. Electronic address:
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State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China. Electronic address:
Polyvinyl chloride (PVC) is a widely used plastic, but the potential risk of heavy metal additive release from PVC microplastics (MPs) has not been fully explored. This study evaluates the release of lead (Pb) from recycled PVC MPs under natural conditions. The released Pb concentration in the dark was 1079.
View Article and Find Full Text PDFWater Res
December 2024
State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
Dissolved organic matter (DOM) represents one of the most active elements in aquatic systems, whose fraction is engaged in chemical and biological reactions. However, fluorescence, molecular diversity and variations of DOM in groundwater systems with the alteration of surface water recharge remain unclear. Herein, Excitation-emission matrix (EEM) fluorescence spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with principal component coefficients, parallel factor analyses (PARAFAC) with two‒dimensional correlation spectroscopy (2D-COS) were applied in this study.
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View Article and Find Full Text PDFChemistry
January 2025
Shandong University, School of Chemistry and Chemical Engineering, 27 Shanda Nan Road, 250100, Jinan, CHINA.
Photophysical properties of condensed systems generally originate from collective contributions of all components in their stochastically fluctuated structures and are strongly influenced under strain of chromophores. To precisely identify how the stochastically fluctuated monomers synergistically manipulate the properties, we propose a statistic strategy over sufficient ab initio molecular dynamics (AIMD) samplings and for the first time uncover that synergistic oscillatory twisting (SOT) of neighboring under-strain monomers manipulates the bifunction of rubrene crystal. The under-strain trunk SOT can regulate both singlet fission (SF) and triplet-triplet annihilation (TTA), enabling their coexistence and dominance switching by dynamically modulating the matching of excitation energies.
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