ChemPhotoChem最新文献

Metallophotoredox catalysis is very useful in transforming the chemical moieties for readily available diverse scaffolds. This study presents an efficient and concise methodology devised for decarboxylative oxidation of aliphatic carboxylic acid through manganese (II) acetate-catalyzed visible blue light-induced homolysis. The control experiments showed the presence of peroxide radical along with singlet oxygen suggesting the radical pathway. The light on/off experiment proved that continuous irradiation of light is essential for efficient photocatalytic decarboxylative oxygenation reaction. The established protocol is applicable for both primary and secondary carboxylic acids to afford aldehydes and ketones, respectively, in good yields.

This article presents an in-depth study on the use of tetrazine-based coordination polymers as photocatalysts for the treatment of wastewater contaminated with organic pollutants. The synthesis of a Zn-based MOF incorporating s-tetrazine dicarboxylic acid as an organic ligand is detailed, following a solvothermal method. Analysis of the crystalline structure reveals a three-dimensional porous network characterized by pores approximately 8 Å wide, forming a highly interconnected material. The photocatalytic activity of this material is then investigated for the degradation of ibuprofen under simulated solar irradiation. The reaction mechanism and the intermediate species involved in the degradation pathway are elucidated. This research contributes to a better understanding of tetrazine-based materials in aqueous-phase applications and highlights their potential for sustainable environmental treatment strategies.

Freshwater pollution is a critical global issue, requiring efficient, eco-friendly treatment technologies. In this study, a new ternary nanocomposite photocatalyst was fabricated by combining silver phosphate (Ag₃PO₄) with platinum nanoparticles (Pt NPs) and polymethyl methacrylate (PMMA), a flexible long-chain polymer. The nanocomposite was prepared using coprecipitation, ultrasonic blending, and light-induced reduction. Structural and chemical analyses confirmed successful integration of all components. (XRD) X-ray Diffraction verified the body-centered-cubic phase of Ag₃PO₄, while X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy evidenced the presence and interaction of Ag₃PO₄, Pt, and PMMA. (TEM) Transmission Electron Microscopy revealed PtNPs (5–15 nm) uniformly anchored to the PMMA-coated Ag₃PO₄ surface, displaying varied morphological features. Optical characterization via UV–vis spectroscopy showed a clear reduction in bandgap, enhancing visible light absorption. The Pt@PMMA/Ag₃PO₄ photocatalyst demonstrated outstanding contaminant removal under visible light, achieving 94.20% breakdown of imidacloprid (IM) insecticide in 60 min and near-total removal of acridine orange (ACO) dye in just 15 min. This enhanced performance is attributed to increased light utilization from Pt, larger reactive surface area, and efficient charge separation and transport facilitated by the polymer network, as evidenced by photocurrent response and reduced photoluminescence. The currently developed Pt@PMMA/Ag₃PO₄ nanocomposite shows strong potential as a high-performance, sustainable photocatalyst for light-driven water purification.

Metastable-state photoacid (mPAH) has become a common tool for controlling and driving chemical processes with light. mPAHs with fast reverse reactions are desirable for precise temporal control or generating quick pulses of proton concentration. In this work, different approaches towards fast reversing mPAHs are studied. Experimental and computational results showed that stabilizing the charge–transfer intermediate is an effective way to increase the rate. A novel mPAH with a reverse reaction ≈500 times faster than the most used mPAH in methanol is developed. Another water-soluble mPAH showed a reverse reaction with a rate constant of 7.8 s⁻¹, which is the fastest ever reported. The half-life of the acidic state is calculated to be 89 ms, which allowed to demonstrate sub-second switching using this mPAH.

Beginning in 2017, the groups of Nicewicz, Burton, Lambert, and others have reported an ever-widening array of formally redox neutral nucleophilic aromatic substitution (S_NAr) reactions that proceed via an aromatic radical cation intermediate. However, the roots of this reaction extend far back more than 50 years to foundational work by Nyberg, Kochi, Cornelisse, and Eberson. Unfortunately, much of this early precedent appears to have been overlooked, despite the fact that it offers many potentially useful mechanistic insights into the more modern transformations. Additionally, it is found that this early work has not previously been reviewed in the unified context of nucleophilic aromatic substitution. In this review, a glimpse into the past is provided before discussing the exciting developments of the last decade in this area. The review is concluded with an overview of some of the potential growth opportunities that remain.

Cancer remains a major global health challenge, necessitating the development of alternative therapies that minimize side effects and overcome drug resistance associated with conventional treatments. In this study, it reports the synthesis and characterization of a series of platinum(II) complexes based on azadipyrromethene (ADPM) ligands as novel photosensitizers for photodynamic therapy (PDT). These complexes are designed to enhance light absorption and photochemical activity through the incorporation of heavy atoms. Their photophysical properties—including absorption spectra, fluorescence emission, and singlet oxygen generation efficiency—are systematically investigated. The complexes exhibited strong absorption in the visible region and high singlet oxygen yields, indicating their suitability for PDT applications. In vitro assays using several cancer cell lines demonstrate low cytotoxicity under dark conditions, whereas light activation induces a significant cytotoxic response. Flow cytometry analysis further confirms that the treatment induces apoptotic cell death. These effects were found to be both light- and concentration-dependent. Overall, this study's results demonstrate the potential of these platinum–ADPM complexes as effective and selective PDT agents, offering a promising strategy for the development of safer and more targeted cancer therapies.

In this study, it is investigated how the N-substitution pattern modulates the excited-state intramolecular proton transfer (ESIPT) in polysubstituted imidazoles, a class of compounds with promising photophysical properties. The selective use of a single isomer, either enol or keto, has emerged as a valuable strategy in developing new functional molecules. Using a combination of experimental and theoretical methods, it is addressed how N-alkyl substituents in combination with a 2-(methoxy)phenyl group significantly influence the conformation and stabilization of enol and keto tautomers involved in the ESIPT process. Single-crystal X-ray diffraction reveals a clear influence on the dihedral angle involved in the ESIPT pathway in the crystalline solid state, while (time-dependent) density functional theory reveals the importance of conformational flexibility and substituent π-donation in shaping the excited-state potential energy surface to access a regime of tunable ESIPT. Supported by steady-state solvent-polarity-dependent emission, aggregation-induced emission, and viscosity-dependent emission, an enhanced emission correlated with the stabilization of a specific isomer is demonstrated.

The advent of photoredox catalysis has created a massive buzz in the field of synthetic organic chemistry. As the photoredox process is invariably mediated by the transfer of single electrons, species such as radical cations are inevitable. These species have orcastracized various synthetic transformations that otherwise would have been difficult to achieve. One such class of transformations is the cycloaddition reaction. For driving such reactions, it is often necessary that the radical and cation sites are present on different atoms, in other words, are distal or “distonic” in nature. In the present review, the development of distonic radical cations has been brought forth and their tactical exploitation over the years for the purpose of cycloaddition reactions in the visible-light realm. The entirety of the manuscript has been divided into categories discussing [2 + 2], [3 + 2], and [4 + 2] cycloadditions. In each case, the distonic radical cation that drives the cycloaddition has been highlighted along with necessary discussions, providing readers with an opportunity to appreciate the power of these wonderful intermediates.

This study reports the synthesis of γ-Al₂O₃ supported CuO (C-AlO14) material via impregnation technique. The synthesized C-AlO14 photocatalyst successfully degraded crystal violet (CV) dye via photoactivation of peroxymonosulfate (PMS). The synthesized photocatalysts are thoroughly examined using a variety of techniques, including energy dispersive X-ray spectroscopy, scanning electron microscopy, X-ray diffraction analysis, and fourier transform infrared spectroscopy. The Tauc plots indicated the band gap energy of C-AlO14 was 2.1 eV compared to 1.67 eV for CuO and 3.3 eV for γ-Al₂O. The results indicated that CV (10.0 mg L⁻¹) is almost entirely eliminated (99%) by using C-AlO14 (30 mg) in the presence of PMS (2.0 mM) at pH 6.8 under 30 min of UV irradiation. Scavenger studies indicate that the reaction system produces SO₄^•−, ^•OH, h⁺, and O₂^•−. Accordingly, detailed charge transfer pathway mechanism is explored for UV/C-AlO14/PMS system. Furthermore, degradation intermediates of CV are identified, and subsequently degradation pathways are proposed. Ecological structure activity relationships analysis indicated that UV/C-AlO14/PMS process degrades organic contaminants by environmentally safe route.

Multiresonant thermally activated delayed fluorescence (MR-TADF) materials have emerged as next-generation OLED emitters owing to their narrowband emission, high color purity, and potential for 100% exciton utilization. Among the various MR-TADF scaffolds, carbonyl/nitrogen-based, quinolino[3,2,1-de]acridine-5,9-dione (QAO) cores have attracted significant attention due to their modularity and electronic tunability. This review article presents a systematic analysis of recent advancements in QAO-based emitters, categorized into three molecular design strategies: core locking, core substitution, and core extension. Core locking enhances rigidity, minimizes vibrational loss, and narrows emission profiles critically mandated by blue-emitting MR-TADF systems. Substitution at key positions enables fine control over emission wavelength, ΔE_ST, and photoluminescence quantum yield (Φ_PL). Core extension via π-conjugation elongation or fused aromatic units leads to improved device efficiencies and diverse emission colors, including green and deep-blue electroluminescence. Collectively, these strategies have produced emitters with Φ_PL exceeding 90%, EQEs above 30%, and full-width half maximums as low as 20 nm. We conclude by highlighting current limitations, including RISC bottlenecks, doping concentration effects, and synthetic challenges, while proposing design pathways toward next-generation multifunctional, solution-processable, and chiral MR-TADF materials. This review article provides a roadmap for advancing carbonyl-nitrogen based MR-TADF emitters toward high-performance OLED technologies.