ChemPhotoChem最新文献

Understanding the fundamental mechanisms of ultrafast charge-transfer dynamics in organic solar cells is crucial for developing efficient and sustainable energy technologies. Despite intensive efforts in the last two decades, a complete understanding of the interplays among radiation, electrons, and vibrations has not been achieved yet. In this work, the laser-induced charge-transfer dynamics of quaterthiophene/fullerene, a prototypical donor/acceptor complex, are investigated using real-time time-dependent density functional theory coupled with Ehrenfest nuclear dynamics. Femtosecond radiation in resonance with the lowest-energy transitions in the donor reveals three distinct excitation regimes: weak pulses with intensities below 3 GW cm$$ fail to initiate charge transfer, medium pulses with intensities between 3 and 36GW cm$$ effectively trigger charge transfer in agreement with experiments, while stronger fields significantly perturb the system, inducing relevant transient effects. Detailed analysis of the population dynamics highlights the critical role of vibrations in quaterthiophene in facilitating electron transfer to the acceptor. This study demonstrates the high sensitivity of charge-transfer dynamics to pulse intensity and the interplay between electronic and vibronic couplings, providing crucial insights into the initial light-matter interaction processes responsible for charge transfer in organic donor/acceptor interfaces.

Barrett, S.; Nieves, J.; Collins, E.; Fieglein, V.; Burns, M.; Guerrero, J.; Mouer, L.; Brittain, W. J. Isomer-Dependent Melting Behavior of Low Molar Mass Azobenzene Derivatives: Observation of a Higher Melting Z-Isomer ChemPhotoChem 2024, 8(9), e202400084.

In the Acknowledgements, we incorrectly cited an award number. The text “This work was supported by the National Science Foundation: Texas State-UT PREM Center for Intelligent Materials Assembly, DMR-21,122,041, and the Research Experience for Undergraduates Site: A Chemistry REU on Molecular Innovation and Entrepreneurship, CHE-1,757,843” is incorrect. This should have read: “This work was supported by the National Science Foundation: Texas State-UT PREM Center for Intelligent Materials Assembly, DMR-2,122,041, and the Research Experience for Undergraduates Site: A Chemistry REU on Molecular Innovation and Entrepreneurship, CHE-1,757,843.”

The conclusions of the work are not altered.

We apologize for this error.

Conventional electronic circular dichroism (ECD) spectroscopy fails when it comes to distinguishing chiral compounds with identical or nearly similar spectra. But what if we could harness solid-state anisotropy to break this limitation? In this article, it is demonstrated how CD anisotropy (CDA) uncovers critical differences between two well-known packing polymorphs of finasteride despite their nearly similar pellet ECD spectra. Using ECD imaging (ECDi) and TDDFT-simulated spectra from X-ray structures, it is shown that the second polymorphic form exhibits a unique CDA signature, setting it apart from the first polymorphic form. This proof-of-concept study paves the way for a new strategy to differentiate chiral solid-state systems that conventional methods might struggle to resolve.

The synthesis and photophysical properties of highly substituted symmetrical difluoro-boron-triaza-anthracene (BTAA) 5a–g and nonsymmetrical difluoro-boron-triaza-cyclopentanaphthalene 8a–h (BTCPN) derivatives are reported. Herein, the 2-pyridone was used as a platform to render these highly substituted structures. The BTAA and BTCPN derivatives were efficiently obtained in five steps and characterized by different spectroscopy methods and X-ray data. An experimental analysis of the substituent effect on the photophysical properties of 5a–g and 8a–h was performed. The leading absorption bands of 5a–g and 8a–h are observed at ca. 348 nm, and the emission bands at ca. 536 nm. From series 5a–g and 8a–h, the compounds 5c and 8c showed the highest fluorescence quantum yield obtained in CH₂Cl₂ (φ = 58 and 76%, respectively). The large quantum yield of 5c and 8c is related to a small HOMO-LUMO gap, analyzed by cam-B3LYP/6-311++g**/6-311+g*. A bifurcation of the excitation pattern improves the quantum yield 8a compared to 5a. The large quantum yield of 8a is explained by two probable transitions involving the HOMO-LUMO and HOMO-LUMO + 1 excitation processes.

Photoelectrochemical hydrogen production is a promising and cost-effective strategy to provide clean and sustainable fuel. Due to its excellent electrical and optical properties, tungsten trioxide (WO₃) is one of the most studied electrode materials in this field, and it is well known that the incorporation of pores into the semiconductor can improve its photoelectrochemical performance. Using a facile and scalable template-assisted sol–gel technique, porous WO₃ thin films were tailored by simply varying the number of dip coating cycles. By crystallizing these films at 400 °C, a $$-orthorhombic/$$-monoclinic crystal structure and an average surface area of 32 m² g⁻¹ were obtained. By optimizing the layer thickness of these photoanodes on fluorine-doped tin oxide, photocurrents of up to 3.3 mA cm⁻² at 1.23 V_RHE (in 0.1M H₂SO₄, pH = 0.71) were achieved without the use of any co-catalysts or sacrificial agents. Our photoelectrodes also showed highly reproducible photocurrents, and their high stability was proven in cycling tests, long-term measurement and post-photoelectrochemical characterization. Our work represents a very simple preparation optimization to achieve high-performing WO₃ photoanodes for photoelectrochemical applications.

Photodynamic therapy (PDT) is a noninvasive therapeutic approach for treating cancer and various other diseases. A PDT system relies on three key components: a light source, photosensitizers (PSs), and oxygen. Conventional PDT, which utilizes external light sources to activate PSs, has already been approved for clinical use. However, external light has limited tissue penetration depth and may sometimes cause photoallergic reactions. As a result, internal light sources, such as chemiluminescence (CL) and bioluminescence (BL), have emerged as promising alternatives for future PDT applications. In this review, recent advances in CL/BL-based PDT systems over the past five years are summarized and future trends and design strategies are proposed to guide further research. Specifically, 1) “All-in-one”; 2) covalent linkage; 3) direct PDT for CL-based PDT systems and 1) fusion protein; 2) gene transfection and 3) engineered microorganisms for BL-based PDT systems are discussed. Among these strategies, the “All-in-one” approach—which encapsulates all necessary components within a single delivery system—is possibly the most feasible for optimizing PDT efficacy and the easiest to integrate with chemotherapy or immunotherapy. To advance CL/BL-based PDT toward clinical translation, further evaluation is needed regarding the toxicity and cost of well-designed systems.

The extensive use and improper disposal of nitro-antibiotics in veterinary medicine pose significant environmental and health risks, necessitating sensitive and selective detection methods. Furthermore, distinguishing between nitroimidazoles and nitrofurans remains challenging. Here, an amino acid-scaffolded metal nanocluster-based differential nitro-antibiotic detection strategy leveraging the inner filter effect (IFE) is presented. Nanoclusters are engineered to align with the distinct absorption maxima of nitroimidazoles (λ_abs^max = 320 nm) and nitrofurans (λ_abs^max = 370 nm). L-tyrosine-capped silver nanoclusters (Tyr-Ag NCs) (excitation/emission: 320/410 nm) showed significant photoluminescence (PL) quenching in response to both nitro-antibiotics classes, enabling a turn-off-based detection method. In contrast, L-tryptophan- and L-cysteine-capped copper nanoclusters (Trp-Cu and Cys-Cu NCs), with excitation/emission around 380/500 nm, overlapped spectrally only with nitrofurans, enabling selective quenching and simple visual detection without instrumentation. All three NCs demonstrated nanomolar sensitivity, high selectivity, and minimal interference from non-target species, with their detection mechanisms elucidated in detail. The practicality of the assay is validated through the successful detection of nitro-antibiotics in cow milk and groundwater, demonstrating its reliability in real-world samples. Overall, this study establishes a strategic sensing platform that intentionally leverages the IFE—traditionally considered an experimental artifact—as a powerful and selective tool for antibiotic detection.

Organic room-temperature phosphorescence (RTP) materials have received considerable research interest in photoelectric devices, sensing and imaging, and information encryption owing to the advantageous properties, including low toxicity, broad structural tunability, outstanding processability, and good biocompatibility. Despite the progress made in the past two decades, obstacles such as limited material structure and complex regulation processes are still persisting. In this minireview, the research advances in the RTP of propeller-like organic molecules according to the molecular skeleton will be summarized. Future perspectives and remaining challenges will be discussed at the end.

Optical readouts have gained a considerable attention due to their high spatial resolution, high signal to noise ratio and fast response times. Among these, light-emitting diodes (LEDs) as optical transducers enable to encode chemical information in the current passing through the diode and as a consequence in its light emission amplitude. Recently, the synergy between the principle of bipolar electrochemistry and the optical and electric advantages of LEDs have been explored, in order to develop novel and straightforward approaches to visualize chemical information. This has been increasingly exploited in multiple applications ranging from electroanalysis to chiral recognition, dynamic systems, and multimodal imaging. This review aims to highlight the use of endogenous (thermodynamically spontaneous) and exogenous (externally driven) bipolar electrochemistry for the design of wireless optical readouts based on the operating principle of LEDs.

A new concept for fluorescent probes capable of reporting on the concentrations of weak bases in aqueous solution was recently reported, and suggested as a potential tool for studying cellular buffer systems and metabolite pools (Jakobsen et al., Chem Sci, 2025, 16, 7450). These probes are based on proton coupled electron transfer (PCET) quenching of a phenol substituted diazaoxatriangulenium (DAOTA⁺) fluorophore, promoted by the weak bases acting as proton acceptors for the phenol group. The fluorescence lifetime is reduced as function of the proton transfer (PT) rate and base concentration. Herein, we report the synthesis of a new series of related DAOTA+ probes designed to elucidate the involvement of water bridges in PT. The 5-hydroxy-3-benzoic acid substituted DAOTA⁺ probe showcases intramolecular PT that can only happen by water bridging between the carboxylate proton acceptor and phenol donor groups. This exemplifies how the PCET based PT probes can be designed to investigate the role of Grotthuss-like water bridges in acid/base reactions. Furthermore, the negatively charged carboxylate group, through electrostatic repulsion, prohibits ground state association between the probe and negatively charged bases. These new probes showcase a further development of dynamic PCET probes for studies of PT rates in complex systems.