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Long-lived triplet states are critical intermediates of thiobases for their applications in photodynamic therapy and as photoprobes for DNA/RNA-protein interactions, where thiobases are embedded in DNA/RNA and exist as thionucleosides. However, sugar moieties accelerate triplet decay rates, which is a common issue that must be resolved for thionucleosides. Here, we explore whether protonation of 2-thiocytosine (2tCyt) and 2-thiocytidine (2tCyd) under acidic pH can alter their triplet decays. Femtosecond spectroscopy demonstrates that 2tCytH and 2tCydH exhibit similar triplet lifetimes (3.1 ns), suggesting protonation diminishes the influence of ribose on triplet decay. Notably, the triplet lifetime of 2tCydH is 2-fold prolonged compared to 2tCyd. Further calculations reveal protonation effectively weakens the influence of ribose by altering electronic structures of triplet states and inhibiting the photoisomerization leading to rapid decay. These findings point to a new avenue of using protonation to modulate triplet decay dynamics of thionucleosides and develop pH-responsive strategy in photochemical applications.
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http://dx.doi.org/10.1021/acs.jpclett.4c02575 | DOI Listing |
Phys Chem Chem Phys
September 2025
Department of Chemistry and Key Laboratory for Preparation and Application of Ordered Structural Materials of Guangdong Province, Shantou University, Shantou 515063, P. R. China.
The photophysical properties of two new Bodipy dimers are investigated using a variety of techniques, including steady-state UV-vis absorption and fluorescence spectroscopy, femtosecond and nanosecond transient absorption spectroscopy, and pulse laser-excited time-resolved electron paramagnetic resonance (TREPR) spectroscopic methods. The dimers are formed by the Bodipy units rigidly linked by the orthogonal phenylene bridge. One of the dimers is composed of iodinated units, and the other is not.
View Article and Find Full Text PDFJ Hazard Mater
August 2025
State Key Laboratory of Water Pollution Control and Green Resource Recycling, School of the Environment, Nanjing University, Nanjing, China; Institute for the Environment and Health, Nanjing University Suzhou Campus, Suzhou, China. Electronic address:
The in-situ utilization of dissolved organic matter (DOM) for photosensitized activation of chemical oxidants towards micropollutant abatement presents a promising strategy aligned with the UN's Sustainable Development Goals. This study investigates the degradation of micropollutants via DOM-mediated photosensitized activation of peracetic acid (PAA) under solar irradiation and elucidates the underlying mechanisms. In wastewater effluent containing 5 mg/L DOM and 83 μM PAA, sunlight exposure facilitated DOM-mediated PAA activation, increasing the concentration of oxidative reactive species (ORS) by 50 % compared to DOM-free conditions.
View Article and Find Full Text PDFAdv Mater
August 2025
State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis, Key Laboratory of Synthetic and Self-Assembly Chemistry for Organic Functional Molecules, Ningbo Zhongke Creation Center of New Materials, Shanghai Institute of Organic Chemistry, Universit
Biomedical hydrogels are integral to a wide range of applications, with their efficacy critically hinging on precise delivery and successful gelation at targeted sites. Nevertheless, existing technologies that provide reliable, visual confirmation of gelation and accurate localization remain very limited. Here organic afterglow emitters are reported that are designed with small phosphorescence rate (k ≈ 0.
View Article and Find Full Text PDFMacromol Rapid Commun
August 2025
State Key Laboratory of Flexible Electronics (LOFE) & Institute of Flexible Electronics (IFE), Northwestern Polytechnical University, Xi'an, China.
Amorphous organic polymers with long-lived room-temperature phosphorescence (RTP) characteristics offer intriguing possibilities to advance information security, biological imaging, optoelectronic devices, and intelligent sensors. Despite the recent advances, access to phosphorescent polymers with excellent stretchability and shape memory performance remains a challenge. Herein, nanostructured RTP block copolymers biomimicking mussel cuticles were achieved by atom transfer radical polymerization (ATRP).
View Article and Find Full Text PDFJ Chem Phys
August 2025
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Conical intersections (CIs) play an important role in photochemistry, allowing for ultrafast radiationless decay in processes such as photodissociation. In addition to these natural CIs, an external electric field can create light-induced conical intersections (LICIs), as the dipole-field interaction shifts the coupled potential energy surfaces. This work explores the effect of LICIs on the minor molecular (NH + H2) channel of ammonia photodissociation, building on prior work that studied the major radical (NH2 + H) channel.
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