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• The complex affinity with FQs has an order of Fe(III) > Cu(II) > Al(III). • Photochemistry properties of FQs were affected by metal complexation. • FQs-Cu(II) complex was verified by FTIR and theory of electrostatic potential. • Significant changes in toxicity of antibiotics were found after metal coordination. Acid-base dissociable antibiotic-metal complexes are known to be emerging contaminants in the aquatic environments. However, little information is available on the photochemical properties and toxicity of these complex forms. This study investigated the spectral properties of three fluoroquinolones (FQs) with and without metal ions Fe(III), Cu(II), and Al(III) in solutions under different pH conditions, as well as evaluated the changes in toxicity due to the complex with these metal ions using luminescent bacteria (vibrio fischeri). FQs showed a higher tendency to coordinate metal ions under alkaline conditions compared to neutral and acidic conditions, and the formation of complexes weakened the ultraviolet-absorbing ability of FQs. At pH = 7.0, Cu(II) quenched the fluorescence intensity of FQs. Moreover, their Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy were explored, revealing that the coordination sites of Cu(II) in three FQs were situated in a bidentate manner through the oxygen atom of the deprotonated carboxyl group and cyclic carbonyl oxygen atom. This conclusion was further verified by the theory of molecular surface electrostatic potential. In addition, except for complexes of ciprofloxacin-metals, enhanced toxicity of FQs upon coordination with Fe(III) was observed, while reduced toxicity was found for coordination with Cu(II) and Al(III). These results are important for accurately evaluating the photochemical behavior and risk of these antibiotics in aquatic environments contaminated with metal ions. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein we report that readily available 4‐alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4‐alkenylisocoumarins were selectively converted to the corresponding benzo‐homophthalates through a fluoride‐induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4‐alkenylisocoumarins directly yields diversely poly‐substituted naphthalenes and anthracenes without formation of any regioisomer. Photophysical evaluation of a set of thus obtained 1,3‐di‐ and 1,3,4‐trisubstituted anthracenes reveals their distinct intramolecular charge transfer (ICT) character during light absorption in polar solutions and excimer emission from the solid state when a face‐to‐face π‐stacked molecular assembly is present in the crystal packing. [ABSTRACT FROM AUTHOR]

Radical thermally initiated homopolymerization of methacrylic monomers based on aurone has been studied. Photochemical properties of these methacrylic monomers by UV-visible spectroscopy were investigated. It is shown that the new compounds are capable to radical homopolymerization and photoinduced cis-trans isomerization. It was found that increasing the electron donation of the substituent accelerates the process of radical homopolymerization of monomers. It was found that increasing the electron acceptance of the substituent accelerates the process of cis-trans isomerization. The rate constants and half-transformation times of cis-trans photoisomerization were determined by the tangent of the slope of the dependence Ln(Dfss-D0)/(Dfss-Dt) on the irradiation time of the solutions. [ABSTRACT FROM AUTHOR]

1,3‐Disubstituted N‐aryl‐2H‐isoindoles have been synthesized by a cascade reaction of divinyl ethers, which are derived from easily available 4‐bromoisocoumarins, with substituted anilines in HFIP. This cascade reaction consists of a ring‐opening step through addition‐elimination mechanism and the following 5‐exo‐tet type ring‐closing step via the intramolecular nucleophilic substitution reaction. Thus obtained 2H‐isoindoles have been derivatized to high‐order nitrogen‐containing polycycles including less accessible benzo[a]ullazines. [ABSTRACT FROM AUTHOR]

Photophysical properties of a series of bis(arylydene)cycloalkanone dyes with various donor substituents are studied using quantum chemistry. Their capacity for luminescence and nonradiative relaxation through trans–cis isomerization is related to their structure, in particular, to the donor capacity of the substituents and the degree of conjugation due to the central cycloalkanone moiety. It is shown that cyclohexanone central moiety introduces distortions and disrupts the conjugation, thus leading to a nonmonotonic change in their properties. The increasing donor capacity of the substituents causes increase in the HOMO energy (rise in the oxidation potential) and decrease in the HOMO–LUMO gap, which results in the red shift of the absorption spectra. The ability of the excited dye to relax through fluorescence or through trans–cis isomerization is governed by the height of the barrier between the Franck–Condon and S1–S0 conical intersection regions on the potential energy surface of the lowest π-π* excited state. This barrier also correlates with the donor capacity of the substituents and the degree of conjugation between the central and donor moieties. The calculated fluorescence and trans–cis isomerization rates are in good agreement with the observed fluorescence quantum yields. [ABSTRACT FROM AUTHOR]

As a new zero‐dimensional carbon‐based material, carbon dots (CDs) have attracted extensive attention owing to their advantages such as easy preparation and surface modification, good biocompatibility and water solubility, and tunable photochemical properties. CDs have become one of the most promising nanomaterials in the field of fluorescent sensing, bioimaging, and cancer therapy. How to precisely regulate the photochemical properties, especially the absorption, fluorescence, phosphorescence, reactive oxygen species generation, and photothermal conversion of the CDs, is the key to developing highly efficient phototheranostics for cancer treatment. Although many studies on cancer therapy using CDs have been published, no review has focused on the regulation of photochemical properties of CDs for phototheranostic applications. In this review, we summarized the strategies such as the selection of suitable carbon source, heteroatomic doping, optimum reaction conditions, surface modification, and assembly strategy to efficiently regulate the photochemical properties of the CDs to meet the requirements of different practical applications. This review might provide some valuable insight and new ideas for the development of CDs with excellent phototheranostic performance. This article is categorized under:Therapeutic Approaches and Drug Discovery > Emerging TechnologiesNanotechnology Approaches to Biology > Nanoscale Systems in BiologyDiagnostic Tools > In Vivo Nanodiagnostics and Imaging [ABSTRACT FROM AUTHOR]

Triangular all‐metal complexes have aroused our research interest due to their unique structural and properties. Herein, through the facile reduction of μ3‐oxo complex [μ3‐O(PPh3Au)3]+BF4− (1), we synthesized and isolated the triphenylphosphine stabilized triangular tri‐gold complex [(PPh3Au)3]+BF4− (2) for the first time (yield=90 %). Both complexes showed interesting photochemical sensitivity to temperatures and solvents. The cyclic voltammetry of these complexes showed one single oxidation process in CH3CN. These tri‐gold complexes (2 mol % based on the complex itself) were further applied in the catalytic hydroaminations for substituted phenylacetylenes with anilines and gave the corresponding imine products with great catalytic reactivity and regioselectivity without aiding any promoters or additives. When the loading of the tri‐gold complexes was decreased to 1.0 mol%, 95 % and 97 % of conversions were obtained using 1 and 2, respectively. When further decreased the catalyst loading to 0.5 mol% in preparative scale, 83 % and 80 % of isolated yields were achieved, respectively. This method presented great significance for the syntheses of a series of imine‐containing pharmaceutical intermediates even in preparative scale. Moreover, the investigations of catalytic mechanisms of this reaction indicated that these tri‐gold complexes played important roles as efficient pre‐catalysts in hydroaminations. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dye-sensitized solar cells (DSSCs) • Using DFT and TD-DFT, to investigate the impact of the diphenylamine moieties on the planarity, photochemical and photophysical properties of a modeled dyes. • The dyes all have donor and acceptor groups linked by a π-linker group (D-π-A). • Designed dyes have smaller energy band-gap, larger λ max , higher electron-donating power, and higher electron-accepting power. • All the dyes have the potential to be used as photosensitizers in DSSCs. Dye-sensitized solar cells (DSSCs) play a significant role in the development of affordable, safe, and efficient solar energy technology. In this research, we have designed nine new dyes (J01-09) by modifying an experimentally reported thiophene-based dye (DSS) in the literature. The diethylaniline in the DSS as the electron donating group was replaced with diphenylamine to reduce planarity in the dye. The designed dyes all have donor and acceptor groups linked by a π-linker group (D-π-A). Using DFT and TD-DFT, we investigated the impact of the diphenylamine moieties on the planarity, photochemical and photophysical properties of the modeled dyes in isolation. The optimized structures, UV–Vis absorption, photochemical, and photovoltaic parameters were computed to study the photosensitizing capability of the modeled dyes. The photochemical and photovoltaic parameters of the study include; open-circuit voltage (V OC), light-harvesting efficiency (LHE), driving force of electron injection (ΔGinj), driving force of regeneration (ΔGreg), excited-state lifetime (τ), ionization potential (IP), adiabatic ionization potential (AIP), vertical ionization potential (VIP), electron affinity (EA), chemical hardness (η), electrophilicity index (ω), electron-donating power (ω-) and electron-accepting power (ω+) were calculated. Our findings indicate that only J03 and J08 absorb at longer wavelengths (719 and 753 nm respectively) indicating lower absorption energy bandgap compared to the DSS dye, attributed to the extension of conjugation between the thiophene and donor groups. Also, only J03 and J08 exhibited lower ΔGinj values (−0.985 and −0.667 eV respectively) and ΔGreg values (0.245 and 0.179 eV respectively) implying the dyes can be regenerated spontaneously compared to the DSS dye. Therefore, J03 and J08 are more promising to be developed as a superior photosensitizer in DSSCs. [ABSTRACT FROM AUTHOR]

The current study describes the synthesis, electrochemical, computational, and photochemical properties of octa (3-hydroxypropylthio) substituted cobalt (II) (4), copper (II) (5), nickel (II) (6) and zinc(II) (7) phthalocyanine derivatives. These novel compounds were characterized by elemental analysis, ¹H, ¹3C NMR, FT-IR, UV-Vis, and MS. The redox behaviors of these metallophthalocyanines were investigated by the cyclic voltammetric method. The optimized molecular structure and gauge-including atomic orbital (GIAO) ¹H and ¹3C NMR chemical shift values of these phthalocyanines in the ground state had been calculated by using B3LYP/6--31G(d,p) basis set. The outcomes of the optimized molecular structure were given and compared with the experimental NMR values. The photochemical properties including photodegradation and singlet oxygen generation of zinc(II) phthalocyanine were studied in DMSO solution for the determination of its photosensitizer behaviors. [ABSTRACT FROM AUTHOR]

Photodynamic therapy (PDT) is a non-invasive therapeutic modality based on the interaction between a photosensitive molecule called photosensitizer (PS) and visible light irradiation in the presence of oxygen molecule. Protoporphyrin IX (PpIX), an efficient and widely used PS, is hampered in clinical PDT by its poor water-solubility and tendency to self-aggregate. These features are strongly related to the PS hydrophilic–lipophilic balance. In order to improve the chemical properties of PpIX, a series of amphiphilic PpIX derivatives endowed with PEG550 headgroups and hydrogenated or fluorinated tails was synthetized. Hydrophilic–lipophilic balance (HLB) and log p-values were computed for all of the prepared compounds. Their photochemical properties (spectroscopic characterization, photobleaching, and singlet oxygen quantum yield) were also evaluated followed by the in vitro studies of their cellular uptake, subcellular localization, and photocytotoxicity on three tumor cell lines (4T1, scc-U8, and WiDr cell lines). The results confirm the therapeutic potency of these new PpIX derivatives. Indeed, while all of the derivatives were perfectly water soluble, some of them exhibited an improved photodynamic effect compared to the parent PpIX.

Quinoline Schiff bases display potential applications in optoelectronics and laser fields because of their unique optical properties that arise from extensive delocalization of the electron cloud, and a high order of non-linearity. In this context, a new class of conjugated quinoline-derivative viz. N-(quinolin-3-ylmethylene)anilines were synthesized from 2-hydroxyquinoline-3-carbaldehyde in two good yielding steps. The ability of these imines to accept an electron from a donor is denoted by their electron acceptor number and sites, which is calculated using density functional theory (DFT). The optical properties such as FT-IR, Raman, UV-VIS, and EDS spectra were calculated using TD-DFT, which also provided the energy gap, HOMO-LUMO structure. The optical properties of the synthesized imino quinolines were experimentally studied using photoluminescence and absorption spectroscopy. The properties such as Stokes shift and quantum yield were calculated using experimental data. Furthermore, the compound bearing a methyl group on the aryl ring and ZnO nanoparticles (hydrothermally synthesized) were dissolved in toluene, and optically excited with a 355 nm nanosecond laser, which produced a random laser.

This article in view of the Compound 1 to Compound 6 (six) kinds of organic small molecule photovoltaic material preparation, thermal properties, UV-vis absorption spectroscopy, fluorescence spectroscopy, electrochemical properties and its ontology with PC60BM heterostructure of solar cell device is analyzed, in order to explore the performance differences of different organic small molecules, provide theoretical guidance for the preparation and development of photovoltaic materials. The results show that increase in the compound rigid structure helps to improve its thermal stability. The UV absorption spectra and fluorescence spectra of organic photovoltaic small molecules are mainly determined by receptor units, when the receptor cell contains three different kinds of donor cells of organic small molecule optical performance difference is not very big, and the UV absorption spectrum of DPP series is wider than that of the benzothiadiazole series. The bandgap size of the six compounds containing triphenylamine depends mainly on the narrow band gap in the small molecule; the triphenylamine is stronger than the carbazole hole transport capacity and fluorene, but its solubility is relatively poor; the DPP series of optical performance and benzothiadiazole is better, but the PV performance is not as benzothiadiazole series. [ABSTRACT FROM AUTHOR]

Abstract The aim of the present paper was to optimize the properties of phenothiazine photosensitizers (PSs), Azure B and its monobrominated derivative. They were entrapped in multilamellar liposomes of egg phosphatidylcholine (EPC) and dipalmitoylphosphatidylcholine (dpPC). The higher partition coefficient of both PSs in the EPC/water system compared with that of both PSs in the dpPC/water system allowed the selection of EPC to be used for the development of third generation photosensitizers. The optimal phospholipid/phenothiazine ratio and the location of these dyes in the lipid bilayer systems were established. These dyes were found to be located within the polar head group region of the lipid bilayer, which would enhance the effectiveness of the irradiation procedure. In addition, the encapsulation of both photosensitizers in liposomes led to a decrease in the aggregation of these compounds, and consequently to an increase in their singlet oxygen quantum yield (ϕ Δ). The encapsulation of the PSs in lipid vesicles significantly increased their photochemical reactivity, doubling the ϕ Δ value of AzBBr and increasing that of AzB by 60%. The results obtained demonstrate that the vehiculization of these PSs in liposomes allowed the development of third generation photosensitizers with better photochemical properties to be used in potential therapeutic applications. Highlights • Azure B and its monobrominated derivative were encapsulated in multilamellar liposomes. • Liposome encapsulation decreased the aggregation of phenothiazine dyes. • Encapsulated photosensitizers exhibited higher singlet oxygen quantum yield. [ABSTRACT FROM AUTHOR]

In this work we report preliminary results obtained for methacrylic polymers incorporating aurone side-group as photochemical active molecule. The aurone polymers were obtained by a three-step synthetic approach: (2Z)-6-hydroxy-2-(4-R-benzyliden)-1-benzofuran-3(2H)-ones were synthesized by using condensation reation of 6-hydroxybenzofuran-3-one with benzaldehydes; then methacrylate monomers were synthesized by reaction the alcohols with methacryloyl chloride; and the polymers were synthesized by free radical polymerization. Polymers were characterized by 1HNMR spectroscopy and DSC techniques. Their physicochemical properties are determined by absorption, fluorescence excitation and emission spectroscopies. [ABSTRACT FROM AUTHOR]

Arsenic (As) presents high toxicity and strong carcinogenicity, and its health risks are regulated by its oxidation state and speciation. As can form complexes with the surface of minerals or organic matter through adsorption, affecting its toxicity and bioavailability. However, the regulation effect of the interaction of coexisting minerals and organic matter on As fate remains largely unknown. Here, we discovered that minerals (e.g., pyrite) and organic matter (e.g., alanyl glutamine, AG) can form pyrite-AG complexes, promoting As(III) oxidation under simulated solar irradiation. The formation of pyrite-AG was explored in terms of the interaction of surface oxygen atoms, electron transfer and crystal surface changes. From the perspective of atoms and molecules, pyrite-AG showed more oxygen vacancies, stronger reactive oxygen species (ROS) and a higher electron transport capacity than pyrite alone. Compared with pyrite, pyrite-AG effectively promoted the conversion of highly toxic As(III) to less toxic As(V) due to the enhanced photochemical properties. Moreover, quantification and capture of ROS confirmed that hydroxyl radicals (•OH) played an important role in As(III) oxidation in the pyrite-AG and As(III) system. Our results provide previously unidentified perspectives on the effects and chemical mechanisms of highly active complexes of mineral and organic matter on As fate and provide new insights into the risk assessment and control of As pollution. [Display omitted] • Pyrite and alanyl glutamine (AG) formed pyrite-AG complexes in water. • Pyrite-AG enhanced photochemical properties and As adsorption sites. • ROS generated by pyrite-AG was 25.41–30.61% higher than that generated by pyrite. • Pyrite-AG significantly (p < 0.05) promoted As(III) oxidation compared with pyrite. [ABSTRACT FROM AUTHOR]

[Display omitted] • The photophysical properties of heterocyclic analogs of 1,4-cyclohexadiene were studied by theoretical calculation and experiment. • Their photophysical and photochemical properties were found to be related to the incorporation of different heteroatoms on the 1,4-cyclohexadiene ring. • The photophysical properties of heterocyclic analogs of 1,4-cyclohexadiene are meaningful for explaining their photochemical reactivity. The photophysical and photochemical properties of a series of heterocyclic analogs of 1,4-cyclohexadiene were studied by theoretical calculation and experiment. With the incorporation of different heteroatoms, the analogs presented distinct photophysical and photochemical properties from 1,4-cyclohexadiene. Their ultraviolet–visible absorption spectra were measured and found to be related to the heteroatoms on the 1,4-cyclohexadiene ring. Calculation of the geometrical and electronic structures of the ground-states revealed that incorporation of the heteroatom affected the photophysical properties of the molecule. The de-excitation processes and electron transition modes were discussed according to the calculated values of the spin–orbit coupling matrix and the electron-hole distributions of the excited states. The reactive sites and geometrical structures showed that incorporation of a heteroatom into 1,4-cyclohexadiene changed the spin density distribution and thus influenced the photochemical properties. These findings are meaningful in explaining the photo-reactivities of these molecules, and provide foundations for further experimental/theoretical investigations and pharmacological applications based on established structure–property correlations. [ABSTRACT FROM AUTHOR]

The development of industry and the increase in population have caused energy shortages and environmental pollution problems. Developing clean and storable new energy is identified as a key way to solve the problems above. Hydrogen is viewed as the most potential energy carrier due to its high calorific value and pollution-free. To convert solar energy into hydrogen energy, three nickel-based catalysts, Ni(aps)(pys) 2 (aps=2-amino-2-phenylacetic salicylaldehyde) (1), Ni(ads)(pys) 2 (ads=aniline salicylaldehyde, pys=pyridine-2-thiolate) (2), Ni(acs)(pys) 2 (acs=aniline 5-chlorosalicylaldehyde) (3), were synthesized and explored as photocatalysts for hydrogen production. A three-component photocatalytic system for hydrogen production was constructed using target complex as photocatalyst, triethanolamine (TEOA) as electron sacrificial agent and fluorescein (FL) as photosensitizer. Under the optimum conditions, about 1504 μmol of H 2 can be obtained with 25 mg catalyst 2 after 3 hours of irradiation. Finally, the hydrogen-production mechanism was discussed by experimental and theoretical methods., (© 2023 Wiley-VCH GmbH.)

The photochemical properties of 1-aryl-2,4,6-triphenyl-1,4-dihydropyrazines 1 were investigated in conventional solvents. The results demonstrated that 1 were unstable to form N-arylbenzamide 2 and N-arylbenzenecarboximidic acid 3 under irradiation with UV light. The photoreaction mechanism was proposed via a photooxygenation. The photoreaction products were determined by ¹H and 13C NMR, high-resolution mass spectrometry (HRMS), and single crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

As a new zero-dimensional carbon-based material, carbon dots (CDs) have attracted extensive attention owing to their advantages such as easy preparation and surface modification, good biocompatibility and water solubility, and tunable photochemical properties. CDs have become one of the most promising nanomaterials in the field of fluorescent sensing, bioimaging, and cancer therapy. How to precisely regulate the photochemical properties, especially the absorption, fluorescence, phosphorescence, reactive oxygen species generation, and photothermal conversion of the CDs, is the key to developing highly efficient phototheranostics for cancer treatment. Although many studies on cancer therapy using CDs have been published, no review has focused on the regulation of photochemical properties of CDs for phototheranostic applications. In this review, we summarized the strategies such as the selection of suitable carbon source, heteroatomic doping, optimum reaction conditions, surface modification, and assembly strategy to efficiently regulate the photochemical properties of the CDs to meet the requirements of different practical applications. This review might provide some valuable insight and new ideas for the development of CDs with excellent phototheranostic performance. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Diagnostic Tools > In Vivo Nanodiagnostics and Imaging., (© 2022 Wiley Periodicals LLC.)

Novel water-soluble metallophthalocyanines (M: Co, Ni, Cu, Zn) containing azo dye were characterized. The structures were confirmed by IR, UV/vis, ¹H NMR, 13C NMR, mass spectroscopy, and elemental analysis. Photochemical properties and aggregation behavior of zinc phthalocyanines were investigated. Singlet oxygen quantum yields of the zinc phthalocyanines (2d, 3d, 5d, and 6d) were 0.8, 0.57, 0.71, and 0.46, respectively. [ABSTRACT FROM AUTHOR]

Abstract: We report a photochemically tunable photonic crystals (PCs) system, based on azobenzene derivatives covalently grafted onto mesoporous silica photonic crystals (azo-MS-PCs), of which the reflectance at the stopband position can be modulated by alternating UV/Visible (UV/Vis) light irradiation. The stopband position of azo-MS-PCs was found to be dependent on the photoisomerization of azo ligands. The decreased effective refractive index of azo-MS-PCs at the cis-state under UV light irradiation led to a blue-shift of stopband position. Upon irradiation with Vis light, the stopband position was recovered after photoisomerization from the cis-state to the trans-state. The introduction of mesoporous silica matrix could not only enhance the grafting content, mechanical, chemical, and thermal stability of the responsive moieties, but also meet the steric demands of azo photoisomerization process. This work may open a new way to fabricate multi-functional PCs materials with the tunable band gap. [Copyright &y& Elsevier]

Abstract: Organic–inorganic nanohybrids, 3,4-dihydroxycinnamic acid/layered double hydroxide (CA/LDH), 4-hydroxy-3,5-dimethoxycinnamic acid/layered double hydroxide (SA/LDH), and 3-amino-5-triflouromethylbenzoic acid/layered double hydroxide (FBA/LDH) have been synthesized by co-precipitation reaction of organic ultraviolet (UV) ray absorbents such as 3,4-dihydroxycinnamic acid, 4-hydroxy-3,5-dimethoxycinnamic acid, 3-amino-5-triflouromethylbenzoic and Zn2Al layered double hydroxide (LDH). Detailed structural and absorption properties of the nanohybrids were studied by using X-ray diffraction (XRD), FT-IR and UV-Vis transmittance spectra which revealed that organic UV absorbents have been intercalated into the interlayer spaces of LDH and all nanohybrids showed excellent UV ray absorption. All the nanohybrids showed a lower catalytic activity as compared to the net organic UV ray absorbents by applying air oxidation to castor oil. [Copyright &y& Elsevier]

Polyethylene imines having 4-methoxyazobenezene group through methylene spacer groups (PEI6 M) were synthesized and their photochemical, thermooptical as well as photoorientational behavior were investigated. PEI6 M films showed high dichroism and order parameter values after annealing and developed out-of-plane order. Multiply-layered films exhibited reflection band and reflection band was almost disappeared by annealing the films at 80°C. In addition reflection band was again observed by UV light irradiation because of reorientation of azobenzene groups from out-of-plane order to random state. The photochemical control of molecular orientation of PEI6 M between random state and out-of-plane structures were achieved by combination of thermal and photochemical processes. [ABSTRACT FROM AUTHOR]

Abstract: A novel combination for an inorganic–organic nanocomposite material was demonstrated. Anthryl dendron, i.e., poly(amidoamine) dendron with an anthracene chromophore group at the focal point, was incorporated in the interlayer space of ZnAl–NO3 type layered double hydroxide (LDH) through an anion-exchange reaction. The photoabsorption and fluorescence properties of the resulting material were different from those of the bare anthryl dendron molecule. It was suggested that the change in photochemical properties was due to the organization and π–π interaction of anthracene chromophores within the interlayer of the LDH. [Copyright &y& Elsevier]

Abstract: We have demonstrated the synthesis of regioisomerically pure unsymmetrical xanthene derivatives consisting of three units which can be independently modified to control their physical properties. The photochemical properties of the synthetic unsymmetrical xanthene derivatives were investigated in solution by UV–vis absorption and fluorescence measurements, and their cell imaging properties were examined by confocal laser-scanning microscopy. [Copyright &y& Elsevier]

Abstract: Organic ultraviolet (UV) ray absorbents such as cinnamic acid (CA), 3,4-dimethoxycinnamic acid (DMOCA) and p-hydroxycinnamic acid (PHCA) were intercalated into Zn2Al layered double hydroxides (Zn2Al-LDHs) by co-precipitation reaction. The organic–inorganic nanocomposites, Zn2Al-LDH/CA, Zn2Al-LDH/DMOCA and Zn2Al-LDH/PHCA were obtained. XRD patterns showed that the basal spacing of Zn2Al-LDH/CA, Zn2Al-LDH/DMOCA and Zn2Al-LDH/PHCA was 1.80, 1.91 and 1.76nm, respectively. The UV-VIS transmittance spectra of thin films of the samples indicated that all Zn2Al-LDH/organic UV absorbent nanocomposites showed excellent UV ray absorption ability. The catalytic activity studies showed their catalytic activity for the air oxidation of castor oil greatly decreased when the organic UV ray absorbents were intercalated into the interlayer spaces of the Zn2Al-LDHs. [Copyright &y& Elsevier]

Abstract: Self-assembled monolayers (SAMs) of alkylthiol on metals, especially on gold, with photo-functionalities, such as photo-induced electron transfer, control of photo-electrochemical properties, control of electron transfer by photoisomerization, luminescence, and photo-patterning, are reviewed. [Copyright &y& Elsevier]

Abstract: In recent years, it has been shown that chemically modified bacteriorhodopsin (BR) containing large organic cations has a long lifetime of the O state. So it can be used to study the photochemical conversion between the O state and the P state. Chemically modified BR was obtained by adding cations to the deionized blue membrane (dIbR). However, BR molecules were easy to aggregate because the large organic cations were bound to dIbR. In this paper, a water-soluble polymer, polyvinyl alcohol (PVA), was used as a protectant and added to dIbR before the addition of large organic cations. It can prevent the aggregation of the molecules of chemically modified BR. The surface binding of PVA not only affected the stability properties but also played a very important role in controlling the photochemical properties of chemically modified BR. [Copyright &y& Elsevier]

The appearance of quantum size effects in ultradisperse semiconductors, their quantitative analysis, and their effect on the absorption of light and on the photophysical (vibrational relaxation of photogenerated “hot” charge carriers, band-band and “defect” luminescence) and certain primary photochemical processes (the accumulation of excess negative charge by the semiconductor nanoparticles, interphase electron transfer, etc.) are discussed. [ABSTRACT FROM AUTHOR]

The spectro-optical properties of nanoparticles of ZnS have been studied and the structure of the long wavelength edge of the absorption bands of the semiconductor has been analyzed. The influence of the synthesis conditions on the size and optical properties of the nanoparticles of ZnS formed has been investigated. It has been established that oxidative photo-corrosion of zinc sulfide colloids is accompanied by a decrease in the average size of ZnS nanoparticles and an increase in the defectiveness of their surfaces. [ABSTRACT FROM AUTHOR]

The synthesis of a number of new methacrylate esters containing aryl-oxycarbonyl group are described. The monomers produced from the reaction of corresponding aryl-oxycarbonyl methylchlorides with sodium methacrylate, were polymerized in 1,4-dioxane with AIBN as an initiator at 60 °C. The monomers and their polymers were characterized by IR, 1H and 13C NMR spectroscopy. The glass transition temperature and thermal decomposition temperature of the polymers were investigated by DSC-50 and TGA-50 thermobalance, respectively. The activation energies of these polymers of thermal decomposition were evaluated by using the MHRK method. The molecular weights (Mw and Mn) of the polymers were determined by the GPC technique. The photochemical properties of the polymers were also examined. [Copyright &y& Elsevier]

Photodynamic therapy (PDT) is a non-invasive therapeutic modality based on the interaction between a photosensitive molecule called photosensitizer (PS) and visible light irradiation in the presence of oxygen molecule. Protoporphyrin IX (PpIX), an efficient and widely used PS, is hampered in clinical PDT by its poor water-solubility and tendency to self-aggregate. These features are strongly related to the PS hydrophilic–lipophilic balance. In order to improve the chemical properties of PpIX, a series of amphiphilic PpIX derivatives endowed with PEG550 headgroups and hydrogenated or fluorinated tails was synthetized. Hydrophilic–lipophilic balance (HLB) and log p-values were computed for all of the prepared compounds. Their photochemical properties (spectroscopic characterization, photobleaching, and singlet oxygen quantum yield) were also evaluated followed by the in vitro studies of their cellular uptake, subcellular localization, and photocytotoxicity on three tumor cell lines (4T1, scc-U8, and WiDr cell lines). The results confirm the therapeutic potency of these new PpIX derivatives. Indeed, while all of the derivatives were perfectly water soluble, some of them exhibited an improved photodynamic effect compared to the parent PpIX. [ABSTRACT FROM AUTHOR]

Quinoline Schiff bases display potential applications in optoelectronics and laser fields because of their unique optical properties that arise from extensive delocalization of the electron cloud, and a high order of non-linearity. In this context, a new class of conjugated quinoline-derivative viz. N-(quinolin-3-ylmethylene)anilines were synthesized from 2-hydroxyquinoline-3-carbaldehyde in two good yielding steps. The ability of these imines to accept an electron from a donor is denoted by their electron acceptor number and sites, which is calculated using density functional theory (DFT). The optical properties such as FT-IR, Raman, UV-VIS, and EDS spectra were calculated using TD-DFT, which also provided the energy gap, HOMO-LUMO structure. The optical properties of the synthesized imino quinolines were experimentally studied using photoluminescence and absorption spectroscopy. The properties such as Stokes shift and quantum yield were calculated using experimental data. Furthermore, the compound bearing a methyl group on the aryl ring and ZnO nanoparticles (hydrothermally synthesized) were dissolved in toluene, and optically excited with a 355 nm nanosecond laser, which produced a random laser. [ABSTRACT FROM AUTHOR]

One attractive way to harvest solar energy is to use the concepts of natural photosynthesis in an artificial system. In green plant photosynthesis, the solar energy is transformed into usable energy in the form of reduced compounds. The electrons come from water which is oxidized to molecular oxygen, thereby providing the plants with a never ending supply of reducing equivalents. In photosystem II, the photosensitizer is a chlorophyll species, P680, which is coupled to a cluster composed of four manganese ions that catalyses the water oxidation. We have tried to mimic this by the synthesis of a binuclear compound [Ru(bpy)(Mebpy-Mebpy)MnCl(HO)]Cl built on bipyridine ligands containing a Ru(II) moiety (the photosensitizer) and a Mn(II) ion (the donor) linked via a bridging ligand. In the complex, which is structurally defined by NMR, elemental analysis and electrospray mass spectroscopy, we have observed, (1) the Mn is sufficiently close (about 13Å) to interact with the Ru(II) ion, and (2) intramolecular, photochemically induced electron transfer from Mn(II) to the photogenerated Ru(III) moiety after a light flash in the presence of an electron acceptor. We suggest that the synthesis, characterization and observation of intramolecular electron transfer in this novel Ru-Mn compound is an important step towards artificial photosynthesis. [ABSTRACT FROM AUTHOR]

• The porous S-doped ZnO nanowires were fabricated by direct reaction of zinc foil. • The as-synthesized S-doped ZnO nanowire represents a half-arc mesoporous superstructure. • An enhanced photochemical property was observed in the as-prepared nanowires. • The S-doped ZnO nanowires have potential applications in optoelectronic applications. The photochemical properties of nanomaterials have always been a research focus in the preparation and optoelectronic applications of nanomaterials. In this work, the porous S-doped ZnO nanowires with cigarette shape were firstly fabricated by direct reaction of zinc foil in aqueous solution of sodium hyposulfite at constant temperature (65 °C). It can be determined that the as-synthesized nanomaterial is elemental S-doped ZnO nanowire with a half-arc mesoporous superstructure characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersion spectroscopy (EDX). Further, through the characterization of photochemical properties, an enhanced photochemical property was observed, indicating the S-doped ZnO nanowire with half-arc mesoporous superstructur have potential applications in dye sensitized photoelectrochemical cells, gas sensors, biosensors, optoelectronic devices, and so on. [ABSTRACT FROM AUTHOR]