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Главная страница Новости науки Journal of Photochemistry and Photobiology A: Chemistry
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ScienceDirect Publication: Journal of Photochemistry and Photobiology A: Chemistry
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ScienceDirect Publication: Journal of Photochemistry and Photobiology A: Chemistry
  • Preparation of CdS/BiOCl/Bi2O3 double composite system for visible light active photocatalytic applications
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Ashok Kumar Chakraborty, Sumon Ganguli, Sandipan Bera, Wan In Lee

    An efficient visible-light-harvesting (λ ≥ 420 nm) three component system heterojunction photocatalyst, CdS/BiOCl/Bi2O3 was prepared by anchoring of CdS nanoparticles on the surface of BiOCl/Bi2O3 composite. The effect of CdS nanoparticles on the surface of BiOCl/Bi2O3 composite photocatalyst had been justified in enhancing photocatalytic activity towards the degradation of organic pollutants in gas as well as aqueous phase. With the loading of CdS on to the BiOCl/Bi2O3 heterojunction composite photocatalyst, the photocatalytic activity of the CdS/BiOCl/Bi2O3 composite structure has been appreciably improved for the decomposition of 2-propanol (IPA) in gas phase and salicylic acid (SA) in aqueous phase under visible light irradiation (λ ≥ 420 nm). The amount of loading of CdS nanoparticles was optimized to 2 mol% CdS/BiOCl/Bi2O3. Compare to bare BiOCl/Bi2O3 photocatalyst, CdS/BiOCl/Bi2O3 heterojunction demonstrated 2 times decomposition of IPA in gas phase and 1.8 times of SA in aqueous phase after 120 min. of visible light irradiation. At the same time, with this composition the evolution of CO2 from degradation of IPA was 1.9 times higher than that of BiOCl/Bi2O3 composite. The enhanced photocatalytic efficiency is deduced from the electron (eˉ) and hole (h+) transfer among the component semiconductor nanoparticles Bi2O3, BiOCl and CdS due to their relative energy band positions. Several experimental evidences were also provided to confirm the electron-hole transfer among the semiconductors and a mechanistic way has been proposed.

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  • Comparative procedure of photodegradation of methylene blue using N doped activated carbon loaded with hollow 3D flower like ZnS in two synergic phases of adsorption and catalytic
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Shahram Nekouei, Farzin Nekouei

    In the present work, 3D flower like ZnS was synthesized by a sonochemical-solvothermal process and loaded on Nitrogen doped activated carbon (NAC-ZnS). photocatalytic degradation of methylene blue (MB) onto NAC-ZnS investigated in aqueous solution at room-temperature. The whole method was studied in two different processes of adsorption and photodegradation in detail separately with a synergic perspective. Influence of various operational parameters such as pH, composite dose, and contact time for adsorption process, and also pH, composite dose, and degradation time for catalytic process were examined in multivariate method through response surface methodology (RSM) based upon the central composite design (CCD) by design expert7 software. In addition, initial MB concentration as well as calculations of adsorption kinetic and isotherm and catalytic kinetic were done. In NAC-ZnS photodegradation process the mechanism of electron-hole pairs generation was fully studied. MB was successfully photo reduced by NAC-ZnS nanocomposite and investigated in two periodic phases of 110 min and 10 h of irradiation to decay all secondary pollutants resulted from first phase. The products (secondary pollutants) produced from first phase were identified by liquid chromatography–mass spectrometry (LC–MS/MS). Moreover, the NAC-ZnS morphological studies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), Thermo gravimetric analysis (TGA), and energy dispersion spectroscopy (EDS) were performed.

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  • Approach for the electrochemical analysis of hydrophobic compounds included in photo-responsive liposomes
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Silvia Soto Espinoza, Irene Rezzano, Santiago Sobral, Romina Carballo

    A highly hydrophobic porphyrin: di-octadecyl-amide deuteroporphyrin (D-ODA) was synthesized and incorporated into liposomes (Lipo-D-ODA) through self-assembling of the aliphatic chains. From the fluorescence spectra, it was concluded that the long alkyl carboxylate chains accommodate the sensitizer into the lipid bilayer, is less exposed to quenching induced by aggregation. The light excited liposome Lipo-D*-ODA activated the ground state molecular oxygen to produce oxygen singlet or superoxide anion. The electrochemical responses of two structurally different redox-active analytes were studied. Quercetin oxidation at 200 mV was only observed after irradiation on the Lipo-D-ODA/Quercetin, indicating that it is embedded in the liposome and requires membrane rupture. On the contrary, the signal of Ferrocene-ODA was independent of irradiation because the redox polar moieties (Ferrocene) were oriented in aqueous space.

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  • {Ru(CO)x}-core terpyridine complexes: Lysozyme binding affinity, DNA and photoinduced carbon monoxide releasing properties
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Ahmed M. Mansour, Ola R. Shehab

    Reaction of 4′-(2-pyridyl)-2,2′:6′,2″-terpyridine (LPY) and 4′-(4-phenylmorpholine)-2,2′:6′,2″-terpyridine (Lmorph) with {[RuCl2(CO)3]}2 in methanol affords [RuCl2(LPY2 N1N2 )(CO)2] (1) and a mixture of [RuCl2(Lmoph2 N1N2 )(CO)2]/[RuCl2(Lmorph3 N1N2N3 )(CO)] (2), respectively. Their photoactivatable CO releasing properties are investigated upon the exposure to light source at 365 nm. One CO molecule is released from 1 at the excitation wavelength 365 nm, while the ligand changes its bidentate mode into the meridional tridentate one. The illumination profile and the influence of the uncoordinated pyridine arm on CO release are examined by solution 1H and 13C NMR spectroscopy. The electronic transitions are studied by TDDFT. The DNA and hen white egg lysozyme binding affinity of the complexes are studied by UV/Vis. and electrospray ionization mass spectrometry. Stable lysozyme complexes, capable of photo induce CO, are formed via the loss of the labile chloride ligands or terpyridine moiety.

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  • New cyanopyridine based conjugative polymers as blue emitters: Synthesis, photophysical, theoretical and electroluminescence studies
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Naveenchandra Pilicode, Nimith K M, Satyanarayan M N, Airody Vasudeva Adhikari

    Herein, we report the design of three new blue light emitting conjugated polymers (Th-Py-1, Th-Py-2 and Th-Py-3), carrying cyanopyridine ring as a strong electron accepting unit and thiophene as well as phenylene vinylene scaffolds with different substituents, as electron donating moieties. The newly designed monomers/polymers were synthesized using well-known synthetic protocols such as cyclocondensation, O-alkylation, Suzuki cross coupling, Wittig and Knoevenagel reactions. They were well-characterized by spectral, thermal, photophysical, electrochemical and gel permeation chromatography (GPC) techniques. Further, they were subjected to theoretical studies using DFT simulations, performed at B3LYP/TZVP level using Turbomole 7.2 V software package. The new polymers were tested in PLED devices (ITO/PEDOT: PSS/Polymer/Al) as emissive materials. Optical studies revealed that, all the polymers displayed light absorption in the range of 377–397 nm and blue light emission in the order of 432–482 nm, respectively. Further, their band-gaps were calculated to be in the order of 2.55–2.64 eV using both optical and electrochemical data. Furthermore, the TGA study indicated that, they possess good thermal stability with onset decomposition temperature, greater than 300 ⁰C under nitrogen atmosphere. Interestingly, use of these polymers in new PLEDs as emissive layers, has shown improved performance when compared to previously reported polymers in similar type of devices. They show blue light emission with a low threshold voltage of 3.5–3.9 V, affirming an efficient electron injection in the diodes.

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  • The electronic structure and photoactivity of TiO2 modified by hybridization with monolayer g-C3N4
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Hongtao Gao, Jun Jia, Fengjuan Guo, Bijun Li, Dongmei Dai, Xiaoyan Deng, Xien Liu, Chongdian Si, Guangjun Liu

    In this work, first-principles calculation based on density functional theory (DFT) was used to study the enhanced photocatalytic mechanism of TiO2 hybridized with pristine and defective g-C3N4 systematically. The theoretical investigations on both geometry structure and electronic properties, involving band structure, density of states, electron population and charge density difference, were carried out to characterize the improved property of TiO2. It was found that the combination TiO2 with g-C3N4 could be verified for high thermodynamic stability. The interaction between TiO2 and g-C3N4 led to form a built-in electric field at the interface, which facilitated the separation of electron-hole pairs and restrained photo-generated carrier recombination. Furthermore, electrons transiting from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO) promoted the separation of electrons and holes. The effective separation of electron-hole pairs prolonged the lifetime of carries and enhanced the photocatalytic activity of TiO2/g-C3N4. The theoretical investigations could verify the experimental observation results [Chem. Sci., 5(2014), 3946–3951, Phys. Chem. Chem. Phys., 17(2015), 17406–17412] and illustrate the mechanisms of photocatalytic enhancement of TiO2/g-C3N4 composite photocatalysts. Furthermore, the calculated optical absorption curves demonstrated that the absorption edge of TiO2/g-C3N4 composites shifted to visible-light region and its photocatalytic activity increased under visible-light irradiation. The theoretical investigation might provide referable and valuable information for understanding the observed enhanced photocatalytic mechanism in experiments.

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  • Investigation of photophysical properties of 1,8-naphthalimides with an extended conjugation on naphthalene moiety via Suzuki coupling reaction
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Eunju Jang, Ting Ding, Meng Xie, Haishi Cao

    Five 4-substituted 1,8-naphthalimides (1-5), with an extended conjugation on the naphthalene ring, have been synthesized via Suzuki coupling reaction. These derivatives showed a large Stokes shift (up to 200 nm) and longer emission due to the increase of conjugation. Besides strong solvation effect, the low quantum yield were observed in protic solvents compared to in aprotic solvents. The anion forms of 1-5 obtained from reacting with NaH gave a significant red-shift for both absorption and emission spectra. These results provided a new strategy for preparation of fluorescent dyes with a long emission on the basis of 1,8-naphthalimde structure by using Suzuki coupling reaction.

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  • One-pot synthesis, physicochemical and photophysical properties of deep blue light-emitting highly fluorescent pyrene-imidazole dye: A combined experimental and theoretical study
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Salman A. Khan, Abdullah M. Asiri, Al-Anood M. Al-Dies, Osman I. Osman, Mohammad Asad, Mohie E.M. Zayed

    A one-pot multi-component synthesis of 4,5,-diphenyl-2-(pyren-1-yl)-1H-imidazole (DPI) chromophore was performed by the reaction of benzil, pyrene-1-carboxaldehyde and ammonium acetate in acetic acid. Structure elucidation of DPI chromophore was confirmed by spectroscopic techniques (FT-IR, 1H NMR, 13C NMR and mass spectra). The physicochemical and photophysical parameters of DPI chromophore such as extinction coefficient, oscillator strength, dipole moment, stokes shift and fluorescence quantum yield were calculated experimentally and theoretically on the basis of the different solvents polarity to see the effect of the solvents on DPI chromophore. DPI chromophore was also applicable for determination of critical micelle concentration (CMC) of cationic and anionic surfactant such as cetyl trimethyl ammonium bromide (CTAB) and sodium dodecyl sulfate (SDS).

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  • Highly lipophilic and solid emissive N-annulated perylene bisimide synthesis for facile preparation of bright and far-red excimer fluorescent nano-emulsions with large Stokes shift
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Shin-ya Sekida, Tomoe Kameyama, Tomoko Koga, Shingo Hadano, Shigeru Watanabe, Yosuke Niko

    In this study, we synthesized a novel perylene bisimide (PBI) derivative, whose bay area (1, 6, 7, and 12-positions) was annulated by nitrogen atoms (PBI-NC8), and incorporated it into a nano-emulsion for the rapid preparation of bright nanoprobes for bio-imaging. PBI-NC8 was easily obtained and exhibited outstanding solubility in the liquid core of the nano-emulsions (up to 20 wt%), while the parent PBI exhibited limited dissolution (only 0.3 wt%). The resulting nano-emulsions exhibited several ideal features such as greater brightness at a large Stokes shift (140 nm) than that of a quantum dot (QDot 655), sufficient photostability, and long storage stability. These properties were derived from not only the solubility of PBI-NC8, but also its more efficient static excimer fluorescence in the red to far-red region in the aggregated state (Φfl, solid = 0.22) than that of PBI (Φfl, solid = 0.053).

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  • A selective Fluorescence Chemosensor: Pyrene motif Schiff base derivative for detection of Cu2+ ions in living cells
    Publication date: 1 September 2018
    Source:Journal of Photochemistry and Photobiology A: Chemistry, Volume 364

    Author(s): Saravanan Arjunan, Subashini Gopalan, Shyamsivappan Selvaraj, Suresh Thangaraj, Kadirvelu Krishna, Bhuvanesh Nanjan, Nandhakumar Raju, Mohan Palathurai Subramaniam

    A Schiff-base molecule, pyrene motif chemosensor 1 has been synthesized and performed for the fluorescent detection of Cu2+ ions via the inhibition of the photoinduced electron transfer (PET) process. Results were observed the exceptional selectivity towards Cu2+ in DMSO-H2O, (1:1 v/v, HEPES = 50 mM, pH = 7.4) and the association constant (Ka) for chemosensor 1 was binding to Cu2+ system have a value of 1.16 × 104 M−1. In addition, the chemosensor 1 has been used as a fluorescence probe for detecting Cu2+ ions in living cells and its binding phenomenon abilities were confirmed by bio-imaging and spectroscopic methods.

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