ChemPhotoChem最新文献

In microcavity, strong coupling between light and molecules leads to the formation of hybrid excitations, i. e., the polaritons, or exciton-polaritons. Such coupling may alter the energy landscape of the system and the optical properties of the material, making it an effective approach for controlling the light emission from molecular materials. However, due to the complexity of vibrational modes, spectroscopic calculations for organic exciton-polaritons remain to be challenging. In this work, based on the linear-response quantum-electrodynamical time-dependent density functional theory (QED-TDDFT), we employ the thermal vibrational correlation function (TVCF) formalism to calculate the molecular optical spectrum of the lower polaritons (LP) at first-principles level for three molecules, i. e., anthracene, distyrylbenzenes (DSB), and rubrene. The polaron decoupling effect is confirmed from our first-principles computations. The theoretical emission spectra of LP provide new insights for aiding molecular and device design in microcavities that are otherwise hindered due to the lack of vibrational information.

The Front Cover illustrates ultrafast spectroscopic insights into photoexcited energy relaxation pathways of the cationic green fluorescent protein (GFP) chromophore derivatives in aqueous solution. The electron-withdrawing and electron-donating groups (EWGs and EDGs) notably affect the ring-twisting rates on femtosecond-to-picosecond timescales, whereas excited-state proton transfer (ESPT) to solvent molecules occurs more rapidly in competition. Cover design by Jiawei Liu, Cheng Chen, and Chong Fang. More information can be found in their Research Article (DOI 10.1002/cptc.202400037).

The development of highly efficient deep red materials with emission wavelength beyond 650 nm remains a big challenge due to the constraints imposed by the energy gap rule. In this work, a donor-acceptor-donor type emitter, 4,7-bis (10-(4-(tert-butyl) phenyl)-10H-phenothiazin-3-yl) benzo[c][1,2,5] thiadiazole (TBPPTZ) is designed and synthesized. Resulting from the slight twist angle between the donor and acceptor units, TBPPTZ exhibits nearly planar conformation and an extended conjugated structure. TBPPTZ shows a deep red emission peak at 687 nm and aggregation induced emission property with a high photoluminescence quantum yield of 45 % in neat thin film. The optimized organic light-emitting diode (OLEDs) utilizing TBPPTZ as the non-doped emissive layer obtains a high external quantum efficiency (EQE) up to 2.51 % with an electroluminescence (EL) peak at 676 nm, aligning with the Commission Internationale de L'Eclairage (CIE) coordinates (0.68, 0.31), which shows a small EQE roll-off of only 5.6 % at 100 cd m⁻². Additionally, the doped OLED achieves an EQE up to 5.09 %, with an EL peak at 656 nm and CIE coordinates of (0.65, 0.34). The findings of this research not only contribute to achieve highly efficient deep red OLEDs but also offer a novel and effective deep red molecular strategy to realize high-quality OLEDs.

H₂S and CO₂ are common coexisted gases widely existing in natural gas resources, and they need to be treated harmlessly. The traditional Claus treatment process only focuses on H₂S treatment but ignores CO₂. This article systematically conducted theoretical thermodynamic research on the thermocatalytic conversion of H₂S and CO₂. It was found that increasing the reaction temperature and H₂S ratio would have a positive impact on the reaction, while increasing the pressure would lead to a decrease in the conversion rate of reactants and product yield, and introducing COS into the feed gas could have a promoting effect on the reaction. Furthermore, 5 %Mo/Al₂O₃ catalyst was used to preliminarily explore the thermal and photothermal catalysis for H₂S and CO₂ conversion. The results showed that the photothermal catalysis significantly promoted the production of syngas (H₂ and CO), and suppressed COS production in contrast to thermal catalysis. This indicates that the introduction of light could effectively convert H₂S and CO₂ into high-value product syngas, providing important reference value for further research on the conversion of H₂S and CO₂.

A pyrene base luminophore was designed and synthesised under ambient conditions using [4+2] annulation. The synthesised probe PYINDP exhibits good optical properties and emits greenish blue, with high colour purity in solid, solution, and thin film phases. In solution, the CIE coordinates were found to be (0.20, 0.48), and for an aggregated state emitting deep green colour, the CIE values are (0.27, 0.65). Room temperature phosphorescence (RTP) is generated by the luminophore PYINDP, owing to the ISC process. Moreover, the emitter demonstrated an excellent limit of detection values in detecting nitroaromatics (NACs). Bio-imaging studies on HEK, A549 cell lines were successfully carried out to verify the staining capability of PYINDP in biological systems.

The improvement of photodynamic inactivation (PDI) significantly depends on the development of new families of photosensitizers (PSs). In this sense, three BOPHY derivatives (BP, BP-Br and BP-I) were synthetized, studied, and compared to assess their antimicrobial photodynamic properties. BP is an interesting fluorescent probe for cell imaging, while the halogenated analogs (BP-Br and BP-I) are excellent oxygen photosensitizing agents. BP compound presented a fluorescence quantum yield close unity and showed no reactive oxygen species (ROS) production. In contrast, BP-I did not show emission properties but exhibited a high production of ROS through both photodynamic mechanisms, generating singlet oxygen (type II) and superoxide radical anion (type I) under aerobic light irradiation. BP-Br presented an adequate balance between ROS production and emission properties. The photokilling action and the binding to bacterial cells of these macrocycles were evaluated in vitro against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli bacteria. Our results demonstrated that the halogenated BOPHY derivatives were effective PSs in inactivating MRSA using shorter irradiation periods. In addition, the antimicrobial action sensitized by these BOPHYs was potentiated by adding KI. The combination of halogenated BOPHY and KI led to a complete elimination of both Gram-positive and Gram-negative bacteria. Hence, BP-Br and BP-I prove to be potent broad-spectrum antimicrobial PSs. To the best of our knowledge, this is the first time that BOPHY derivatives have been applied to photokill pathogenic microorganisms.

The reactions occurred at excited states are promising and flourished. Many strategies have been discovered reactions initiated by visible light and without transition metals and organic dyes. Diboron ester (B₂cat₂) has special activity towards unsaturated bonds at excited states. In this work, azobenzene and derivatives are reduced to hydrazo with high yield and high selectivity by a very convenient and rapid reaction. Only three factors, B₂cat₂, water and 400 nm lighting or sunlight are necessary. Density functional theory (DFT) studies and NMR results show that azobenzene is excited and a trans to cis isomerization occurs under 400 nm and B₂cat₂ reacts with cis azobenzene through B−B bond cleavage rather than with ground state trans azobenzene. Hydrazo compounds are obtained after hydrolysis with water. Gram level hydrazobenzenes are obtained under sunlight with moderate yields. This strategy is benefit to sustainable chemistry.

The (6–4) photolesion is a key photodamage that occurs when two adjacent pyrimidine bases in a DNA strand bond together. To better understand how the absorption of UVB and UVA radiation by the 2-pyrimidinone moiety in a (6–4) lesion can damage DNA, it is important to study the electronic deactivation mechanism of its 2-pyrimidinone chromophore. This study employs theoretical (MS-CASPT2/cc-pVDZ level) and experimental (steady state and femtosecond broadband spectroscopic) methods to elucidate the photochemical relaxation mechanisms of 2-(1H)-pyrimidinone and 1-methyl-2-(1H)-pyrimidinone in aqueous solution (pH 7.4). In short, excitation at 320 nm leads to the population of the S₁ ¹(ππ*) state with excess vibrational energy, which relaxes to the S₁ ¹(ππ*) minimum in one picosecond or less. A trifurcation event in the S₁ ¹(ππ*) minimum ensued, leading to radiative and nonradiative decay of the population to the ground state or the population of the long-lived and reactive T₁ ³(ππ*) state in hundreds of picoseconds. Collectively, the theoretical and experimental results support the idea that in DNA and RNA, the T₁ ³(ππ*) state of the 2-pyrimidinone moiety in the (6–4) lesion can further participate in photosensitized chemical reactions increasing DNA and RNA damage.

Defect-enriched mesoporous CuO nanosheets (NSs) were constructed to investigate the cooperative photo-Fenton and photothermal-Fenton catalysis on degradation of fluoroquinolones (FQ) antibiotics. The oxygen vacancies provide abundant active sites to bind the substrates and inhibit charge recombination, by all means to enhance Fenton-like activity. Two disparate spectral selective functions of photoexcitation and photothermal conversion were achieved on CuO NS, which to promote the Fenton activity synergistically. Visible light induced photoexcitation to facilitate the generation of Cu⁺ and ⋅OH, while near-infrared light converted into heat to promote charge separation and accelerate medium transport. Ultimately, as a unitary catalyst system, the CuO NS integrated the Lewis acid catalysis, Fenton-like catalysis and photothermal catalysis that rapidly and sustainably degraded antibiotics under near-neutral conditions.

Covalent organic frameworks (COFs), newly developed materials, exhibit considerable promise in the field of catalysis. COFs exhibit captivating catalytic characteristics, including thermal and chemical stability, customizable porosities, and the ability to place active sites flexibly with tunable functions. To establish a connection between structure and activity, this paper provides a thorough justification of the planned creation of covalent organic frameworks for photocatalysis, encompassing H₂ production, carbon dioxide reduction, pollutants reduction and transformation of organic substances. We have investigated the catalytic sites that are active within covalent organic frameworks, encompassing the metals, molecular catalysts, and catalyst with single atom (SACs); the reactive skeleton/linkages; and the reactive pendant groups. This exploration aims to establish the benefits of using COF-based catalysts compared to traditional catalysts. Despite the new advantages, numerous difficulties have also been noted with regard to the future. The objective of this review is to make it easier to design COF-based composite materials for practical uses.