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Triplet-State Photochemistry of Dissolved Organic Matter: Triplet-State Energy Distribution and Surface Electric Charge Conditions
摘要： Excited triplet states of chromophoric dissolved organic matter (3CDOM*) are highly reactive species in sunlit surface waters and play a critical role in reactive oxygen species (ROS) formation and pollutant attenuation. In the present study, a series of chemical probes, including sorbic acid, sorbic alcohol, sorbic amine, trimethylphenol, and furfuryl alcohol, were employed to quantitatively determine 3CDOM* and 1O2 in various organic matters. Using a high concentration of sorbic alcohol as high-energy triplet states quencher, 3CDOM* can be first distinguished as high-energy triplet states (>250 kJ mol?1) and low-energy triplet states (<250 kJ mol?1). The terrestrial-origin natural organic matter (NOM) was found to mainly consist of low-energy triplet states, while high-energy triplet states were predominant in autochthonous-origin NOM and effluent/wastewater organic matter (EfOM/WWOM). The 1O2 quantum yields and electron transfer quantum yield coefficients (f TMP) generated from low-energy triplet states remained constant in all tested organic matters. External phenolic compound showed quenching effects on triplet-state formation and tended to have a higher quenching efficiency for aromatic ketone triplet states, which are the main high-energy triplet states. In comparison with terrestrial-origin NOM, autochthonous-origin NOM and EfOM/WWOM presented lower reaction rate constants for sorbic amines and higher reaction rate constants for sorbic acid, and these differences are likely due to dissimilar surface electric charge conditions. Understanding the triplet-state photochemistry of CDOM is essential for providing useful insights into their photochemical effects in aquatic systems.
关键词： surface charge,triplet-state photochemistry,energy distribution,dissolved organic matter,reactive oxygen species,chemical probes
更新于2025-11-19 16:56:35
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TiO <sub/>2</sub> metasurfaces: From visible planar photonics to photochemistry
摘要： TiO2 metasurfaces have been intensively studied in the past few years. To date, the TiO2 metadevices only used their high reflective index (n). The controllable light extinction coefficient (k) of TiO2 has not been exploited yet. Here, we converted TiO2 metasurfaces to black TiO2 metasurfaces and explored their new opportunities in photochemistry. A complementary metal oxide semiconductor (CMOS)–compatible technique has been developed to reversibly and precisely control the absorption of TiO2 metasurfaces without spoiling their internal nanostructures. Consequently, two types of black TiO2 metasurfaces were realized for photochemical experiments. The metasurface with an ultrawide absorption band can substantially enhance the white light absorption and accelerate the solar-based photochemistry process by a factor of 18.7. The other metasurface with an absorption band of <20 nm only responded to the resonant wavelengths, making the photochemistry process capable of being monitored in real time. In addition, the reversible switch between normal and black states makes TiO2 metasurfaces suitable for dynamic metadevices as well.
关键词： photochemistry,CMOS-compatible technique,black TiO2,dynamic metadevices,TiO2 metasurfaces
更新于2025-10-24 16:33:39
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Organoboron chemistry comes to light: Recent advances in photoinduced synthetic approaches to organoboron compounds
摘要： Photoinduced synthetic approaches to organoboron compounds have attracted significant attention in the recent years. Photochemical activation of organic molecules enables generation of reactive intermediates from a variety of precursors, resulting in borylation methods with improved and broader substrate scopes. The review summarizes recent developments in the area of photoinduced reactions of organoboron compounds with an emphasis on borylation of haloarenes, amine derivatives, and redox-active esters of carboxylic acids, as well as photoinduced rearrangements of organoboron compounds and photoinduced synthesis of organoboron compounds from alkenes and alkynes.
关键词： Diboron reagents,Organoboron compounds,Ring contraction,Borylation,Carboboration,Rearrangements,Photochemistry
更新于2025-09-23 15:23:52
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Oligo(ethylene glycol)/alkyl-modified chromophore assemblies for photon upconversion in water
摘要： Molecular self-assembly is a powerful means to construct nanoscale materials with advanced photophysical properties. Although the protection of the photo-excited states from oxygen quenching is a critical issue, it still has been in an early phase of development. In this work, we demonstrate that a simple and typical molecular design for aqueous supramolecular assembly, modification of chromophoric unit with hydrophilic oligo(ethylene glycol) chains and hydrophobic alkyl chains, is effective to avoid oxygen quenching of triplet-triplet annihilation-based photon upconversion (TTA-UC). While a TTA-UC emission is completely quenched when the donor and acceptor are molecularly dispersed in chloroform, their aqueous co-assemblies exhibit a clear upconverted emission in air-saturated water even under extremely low chromophore concentrations down to 40 μM. The generalization of this nano-encapsulation approach offers new functions and applications using oxygen-sensitive species for supramolecular chemistry.
关键词： photon upconversion,photochemistry,oxygen quenching,self-assembly,triplet-triplet annihilation
更新于2025-09-23 15:23:52
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Kinetics of singlet oxygen sensing using 9-substituted anthracene derivatives$$^{\#}$$#
摘要： Singlet oxygen (1O2), the lowest excited-state of molecular oxygen receives great attention in basic research and clinical and industrial settings. Despite several spectroscopic methods available for 1O2 sensing, fluorescence sensing receives great attention, for which many fluorogenic sensors based on substituted anthracene are reported. Nonetheless, the roles of substituents on the sensing efficiency, in terms of detection time, remain largely unknown. In this work, we examine the 1O2 sensing efficiency of a fluorescence sensor based on a coumarin–anthracene conjugate, which is an electron donor-acceptor dyad, and compare the efficiency with that of 9-methylanthracene. Here, 1O2 is generated using the standard photosensitizer Rose Bengal, which is followed by estimation of the rate of reaction of 1O2 to the sensor and 9-methylanthracene. The second order reaction rate of the sensor is an order of magnitude less than that of 9-methylanthracene. The lower reactivity of the sensor to 1O2 suggests that the roles of substituents, such as electronic interactions, steric interactions and the reactivity of precursor complexes, on sensing efficiency should be carefully considered during construction of fluorogenic molecular sensors.
关键词： photochemistry,reaction kinetics,anthracene,fluorescence sensing,Singlet oxygen
更新于2025-09-23 15:23:52
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Access to Disparate Soft Matter Materials by Curing with Two Colors of Light
摘要： A platform technology for multimaterial photoresists that can be orthogonally cured by disparate colors of light is introduced. The resist’s photochemistry is designed such that one wavelength selectively activates the crosslinking of one set of macromolecules, while a different wavelength initiates network formation of a different set of chains. Each wavelength is thus highly selective towards a specific photoligation reaction within the resist. Critically, the shorter wavelength does not induce ligation of the longer wavelength selective species within the same resist mixture, defined as “wavelength orthogonality.” Uniquely, this dual-color addressable resist system allows generating spatially resolved soft matter materials by simply selecting the curing wavelength, thus constituting a wavelength-orthogonal multimaterial resist with applications ranging from coatings to 3D additive manufacturing of multimaterial architectures.
关键词： photochemistry,λ-orthogonal curing,photoresists,multimaterial coatings,photoligation
更新于2025-09-23 15:23:52
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Excited State Dynamics of [Ru(bpy)3]2+ Thin Films on Sensitized TiO2 and ZrO2
摘要： The excited state dynamics of Tris(2,2'-bipyridine)ruthenium(II) hexafluorophosphate, [Ru(bpy)3(PF6)2], was investigated on the surface of bare and sensitized TiO2 and ZrO2 films. The organic dyes LEG4 and MKA253 were selected as sensitizers. A Stern-Volmer plot of LEG4-sensitized TiO2 substrates with a spin-coated [Ru(bpy)3(PF6)2] layer on top shows considerable quenching of the emission of the latter. Time-resolved emission spectroscopy interestingly reveals the presence of a fast-decay time component (25±5 ns), which is absent when the anatase TiO2 semiconductor is replaced by ZrO2. It should be specified that the positive redox potential of the ruthenium complex prevents electron transfer from the [Ru(bpy)3(PF6)2] ground state into the oxidized sensitizer. Therefore, we speculate that the fast-decaying time component observed may be identified with excited-state electron transfer from [Ru(bpy)3(PF6)2] to the oxidized sensitizer. Solid-state dye sensitized solar cells (ssDSSCs) employing MKA253 and LEG4 dyes, with [Ru(bpy)3(PF6)2] employed as a hole-transporting material (HTM), exhibit 1.2% and 1.1% power conversion efficiency, respectively. This result illustrates the possibility of the hypothesized excited-state electron transfer.
关键词： Photochemistry,Excited-state electron transfer,DSSCs,Ru(bpy)3,Solid state
更新于2025-09-23 15:23:52
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Asymmetric Diarylethenes with Oxidized 2-Alkylbenzothiophen-3-yl Units: Chemistry, Fluorescence, and Photoswitching
摘要： Reversibly photoswitchable diarylethenes (DAEs) with fluorescent closed forms are applied in biology- and material science-related super-resolution microscopy. Yet, their full photoswitchable capacities remain unrevealed and unexplored. Due to limitations in synthesis, only 1,2-[bis-(2-ethyl-1-benzothiophene-1,1-dioxide-3-yl)]perfluorocyclopentenes with two identical or very similar aryl groups attached to C-6 and C-6′ have been prepared so far. DAEs with increased Stokes shifts related to asymmetric structures and the presence of 'push–pull' substituents are introduced in the present study, and their switching power is studied. The new 'simplified' asymmetric DAEs possess higher cycloreversion quantum yields, but lower emission efficiencies than their known analogs with extended π-conjugation paths. Fatigue resistance in organic (acetonitrile and methanol) and aqueous solvents is studied, and the performance in reversible saturable optical fluorescence transition (RESOLFT) microscopy is evaluated. The push–pull structures show an outstanding increase in fatigue resistance, compared with a reference (H/H) diarylethene. Fatigue resistances on the order of thousands of cycles have been observed in acetonitrile solutions without exclusion of air oxygen. The structure–property relationships and facile preparation procedures enable rational design of DAEs applicable as photoswitchable fluorescent probes. A new setup and methodology for measuring switching performance of fluorescent DAEs are introduced.
关键词： photoluminescence,photonics,photochemistry,structure–property relationships
更新于2025-09-23 15:23:52
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Photomechanical organic crystals as smart materials for advanced applications
摘要： Photomechanical molecular crystals are receiving great attention due to their efficient conversion of light into mechanical work and surpassing advantages including faster response time, higher Young’s modulus and ordered structure various measured photomechanical crystals with different motions (contraction, expansion, bending, fragmentation, hopping, curling and twisting) are springing up in the forefront of smart materials research. The photomechanical motions of these single crystals during irradiation is triggered by solid-state photochemical reactions and accompanied with phase transformation. This short review intends to summarize recent developments in the growing research on photoresponsive molecular crystals. The basic mechanisms of different kinds of photomechanical materials are described in detail, the recent advances of photomechanical crystals for promising applications as smart materials are also highlighted.
关键词： crystal engineering,photomechanical crystals,photochemistry,molecular machines,photochromism
更新于2025-09-23 15:23:52
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Synthesis of tetra-substituted phthalocyanines bearing 2-(ethyl(m-tolyl)amino)ethanol: Computational and photophysicochemical studies
摘要： This work presents the synthesis of 4-(2-(ethyl(m-tolyl) amino) ethoxy) phthalonitrile (1) as ligand and its peripherally tetrasubstituted metal-free (2) and metallophthalocyanines (3-5) derivatives. Synthesized compounds were characterized by standart spectroscopy methods. The molecular structure of the ligand (1) was confirmed by single-crystal X-ray diffraction experiment. The crystallographic information file (cif) was uploaded to the data center with CCDC number 1853485. The optimized structure of the ligand (1) and the phthalocyanines (2-5) were obtained by using different metods such as B3lyp, HF and m062x method 3-21g, 6-31g, sdd basis set. In b3lyp/6-31++g(d,p) basis set, 1H and 13C NMR chemical shifts, IR spectrum and UV-Vis spectrum were measured in gas, chloroform and dimethylsulfoxide phase by means of the obtained optimized structure. Besides, the photophysical and photochemical properties of newly synthesized phthalocyanines (2-5) were investigated in DMSO, comparatively. Singlet oxygen quantum yields of the phthalocyanines (2-5) are ranging from 0.28 to 0.70.
关键词： synthesis,Phthalocyanine,photochemistry.,crystal structure,computational studies
更新于2025-09-23 15:23:52