ChemPhotoChem最新文献

Photomechanical organic crystals have gained considerable attention both from the perspective of fundamental research and applications in actuators and soft robots. Needle-like crystals of 1,4-di-p-toluidinoanthraquinone (1), an aminoanthraquinone derivative, oscillate when irradiated with unpolarized pulsed light, based on photothermally resonated natural vibration. However, their photomechanical motion in response to polarized light has not yet been investigated in detail. In this study, the photomechanical behavior of 1 upon linearly polarized light irradiation is examined. The crystal oscillats with a different magnitude depending on the polarization direction of the incident light. The greater the absorption, the larger and more significant the oscillation. Furthermore, the crystal exhibits different oscillation anisotropy depending on the wavelength of the light (375, 520, and 638 nm). This is because the crystal exhibits distinct absorption anisotropy depending on the wavelength of the light, which originates from the directions of the transition dipole moments. This work highlights that the polarization direction can serve as a control parameter, providing an additional degree of freedom to photomechanical crystals.

In the quest for efficient photoelectrolysis devices for solar-driven water splitting, designing a high-performance photoanode compatible with the electrolyte buffer of the photocathode for tandem photoelectrochemical (PEC) cells remains a challenge. One promising solution is the development of an efficient and durable photoanode under acidic conditions. Despite the potential benefits, the limiting factors affecting performance under such conditions are not well understood yet. Two main strategies to enhance photocurrent density and durability are generally considered: applying a surface co-catalyst, or passivating using ultrathin titanium oxide layers as a barrier. In this study, we present a scalable alternative method that combines sol–gel chemistry and dip-coating, to create thinner TiO₂ layers on Mo doped-BiVO₄ photoanodes for surface passivation. We developed Mo-doped-BiVO₄/Co-Pi photoanodes with cobalt-phosphate (Co-Pi) as co-catalyst, which resulted in a major breakthrough by achieving a photocurrent density of 1.9 mA cm⁻² at 1.23V_RHE (pH 6) under standardized illumination conditions, along with a significant improvement in photoanode durability. Additionally, our investigation explores the evolution of the photoanode chemistry within the material after doping, and at the surface after Co-Pi deposition at different stages of the PEC process.

In this work, the photochemical properties of Acid violet 3 (AV3), along with a sacrificial oxidant, MV²⁺, are used to promote its own degradation in aqueous solutions. Irradiation of light at 375 nm produces excited-state AV3 (*AV3) that is able to be oxidized by MV²⁺, as monitored through UV–visible spectroscopy. MV²⁺ is added in various concentrations, showing an increased degradation rate with increasing MV²⁺ concentrations. Degradation of AV3 is still observed in control experiments in which AV3 is illuminated without the presence of MV²⁺. Photodegradation experiments are also performed in deuterated water, showing a five times increased rate of degradation, providing evidence of an inverse kinetic isotope effect. Based on these results, two different degradation pathways are proposed: an energy transfer pathway and an electron transfer pathway. In the electron transfer pathway, *AV3 is oxidized by MV²⁺, which produces MV^•+. MV^•+ interacts with dissolved oxygen to produce reactive oxygen species, likely superoxide radicals (O₂^•−), that are highly reactive and further attack AV3 until it is degraded. In the energy transfer pathway, *AV3 populates a triplet state that is energetically able to sensitize triplet oxygen (³O₂) to singlet oxygen (¹O₂), which can break down AV3.

Carbonyl-containing derivatives have emerged as powerful candidates for room-temperature phosphorescence and thermally activated delayed fluorescence (TADF) due to their ability to harness both singlet and triplet excitons, enabling high device efficiency and exceptional color purity. In this review, the evolution of multiresonant TADF (MR-TADF) molecules derived from benzophenone through direct heteroatom fusion (e.g., acridone, xanthone, thioxanthone) is explored. While benzophenone holds great promise as a TADF emitter, its structural flexibility often leads to nonradiative energy loss. To address this, fused benzophenone derivatives have been developed to enhance TADF performance; however, their intrinsic rigidity presents challenges in achieving blue emission due to the planar nature of the acceptor core. Notably, extended fused-benzophenone structures containing a single carbonyl group have shown remarkable potential for MR-TADF applications. This review highlights key design strategies for engineering TADF and MR-TADF emitters based on benzophenone frameworks. It is critically examined how functional properties are influenced by carbonyl or heteroatom fusion, revealing that the incorporation of oxygen, nitrogen, or sulfur leads to rigid TADF-active emitters, while additional carbonyl fusion enables the development of narrow-band MR-TADF emitters. These insights pave the way for next-generation organic light-emitting materials with superior performance.

Photoprotection is a crucial strategy for preventing the harmful effects of ultraviolet (UV) radiation on human skin, including sunburn, photoaging, and skin cancer. Currently, there is a growing need to develop more sustainable UV filters, as the existing ones may pose environmental risks. In addition to UV protection, cosmetic formulations incorporate antioxidants such as ascorbic acid to neutralize the free radicals generated by UV radiation, helping to reduce the oxidative stress and DNA damage caused. Addressing this challenge, this study explores analogs of naturally absorbing molecules (mycosporine-like amino acids and gadusol) as potential eco-friendly UV filters. These compounds, found in marine organisms, exhibit strong UV absorption and antioxidant properties while being less harmful to aquatic ecosystems. Structural analogs of these molecules are synthesized and evaluated to assess their efficacy as novel UV filters. The findings suggest that these bioinspired compounds provide effective photoprotection, photostability, and safety, and their research and development could contribute to safer and more sustainable cosmetic formulations.

The photoelectrochemical (PEC) platform has been a critical tool in biomolecules detection for its sensitive and selective properties. Herein, a novel signal on–off type PEC biosensing system is designed for sensitive detection of carcinoembryonic antigen (CEA) based on water-soluble pillar[5]arenes (WP5) functionalized the Ag@Au nanowires coated on reduced graphene oxide and graphitic carbon nitride composites (Ag@Au@WP5/RGO-C₃N₄). The RGO-C₃N₄ acts as a carrier for materials due to its large specific surface. Meanwhile, benefiting from the photogenerated electron-holes of RGO-C₃N₄, the local surface plasmon resonance effect of Ag@Au nanowires, the host–guest interaction of WP5 and ascorbic acid (serving as the electron donor), the fabricated PEC sensor shows favorable PEC performance for monitoring the CEA. Under optimal conditions, the detection sensitivity ranges from 0.0005 to 50 ng mL⁻¹ and the limit of detection is 0.18 pg mL⁻¹ (S/N = 3). Most importantly, the PEC sensor shows an excellent performance, satisfying human serum sample analysis. This PEC platform is expected to offer a reliable approach for early cancer diagnosis and demonstrate significant potential for clinical applications.

Photodynamic inactivation (PDI) of microorganisms is an alternative to the use of antibiotics in certain applications, reducing the proliferation of multidrug-resistant pathogens that hinder the control of infectious diseases. In this study we synthesize and evaluate riboflavin derivatives for PDI. The photostability of the compounds and their ability to generate singlet oxygen under visible blue light irradiation are also analyzed. Various homogeneous and heterogeneous systems containing riboflavin derivatives exhibit moderate efficacy in inhibiting the growth of Staphylococcus aureus cultures. These results place the groundwork for designing and developing new photosensitizers based on slightly modified natural products.

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.