- Impact of photosensitizer orientation on the distance dependent photocatalytic activity in zinc phthalocyanine-nanoporous gold hybrid systems
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Nanoporous gold powder was functionalized in a two-step approach by an azide terminated alkanethiol self-assembled monolayer (SAM) and a zinc(ii) phthalocyanine (ZnPc) derivative by copper catalyzed azide-alkyne cycloaddition (CuAAC). A series of different hybrid systems with systematic variation of the alkyl chain length on both positions, the alkanethiol SAM and the peripheral substituents of the ZnPc derivative, was prepared and studied in the photooxidation of diphenylisobenzofuran (DPBF). An enhancement by nearly one order of magnitude was observed for the photosensitized singlet oxygen (1O2) generation of the hybrid systems compared to the same amount of ZnPc in solution caused by the interaction of the npAu surface plasmon resonance and the excited state of the immobilized sensitizer. This interaction was shown to be distance dependent, with decreasing activity for short SAMs with alkyl chain lengths 8 methylene groups due to decreasing energy transfer for long distances. An unexpected distance dependent behaviour was observed for the variation of the peripheral alkyl chain on the photosensitizer revealing a planar orientation of the immobilized photosensitizer on the nanoporous gold surface by a penta-coordinated central zinc ion through interaction with free azide groups from the self-assembled monolayer.
- Epp, Alexander,Klangnog, Khaetthariya,Kohr?de, Mathis,Schnurpfeil, Günter,Steinebrunner, David,Tapia Burgos, Jorge Adrian,W?hrle, Dieter,Wichmann, Andre,Wittstock, Arne
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- Synthesis and application of near-infrared absorbing morpholino-containing aza-BODIPYs
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Morpholino-containing aza-BODIPYs at 3,5-positions were synthesized. The maxima absorption and emission of these dyes locate at the near-infrared region. Aza-BODIPY 1 with the morpholino group as a pH-sensitive functionality could be used to be a pH probe, and the dramatic increase in fluorescence intensity at 675 nm by about 1500 folds. Moreover, the singlet oxygen generation of PS 2 with the dibromo groups at 2,6-positions was more effective than that of the parent dye 1.
- Jiang, Xin-Dong,Jia, Lei,Su,Li, Chen,Sun, Changliang,Xiao, Linjiu
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- OXIDATION OF DIENES BY TRIPHENYLPHOSPHINE PEROXOPALLADIUM
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Thermal reaction of 1,3-diphenylisobenzofuran and tetramethylcyclopentadienone with PdLO2 complex (L = PPh3) gives compounds identical to those produced by singlet molecular oxygen.Photochemical reaction of 1,9-diphenylanthracene with PdLO2 or PdL3 in the presence of oxygen gives the 9,10-endoperoxide adduct.
- Dagonneau, M.,Fauvarque, J. F.
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- A new protocol for the synthesis of new thioaryl-porphyrins derived from 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin: Photophysical evaluation and DNA-binding interactive studies
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A new protocol for the preparation of thioaryl-porphyrins is described. The compounds were prepared from different disulfides employing NaBH4 as a reducing agent. The methodology allowed the preparation of four different thioaryl-porphyrins in very-good to excellent yields under soft conditions, such as short reaction times and smooth heating. Additionally, the photophysical properties of new compounds were determined and experimental and theoretical DNA interactions were assessed.
- Foletto, Patrícia,Correa, Fabiula,Dornelles, Luciano,Iglesias, Bernardo A.,Da Silveira, Carolina H.,Nogara, Pablo A.,Da Rocha, Jo?o B. T.,Faustino, Maria A. F.,Rodrigues, Oscar E. D.
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- Titanium-Carboxylate Metal-Organic Framework Based on an Unprecedented Ti-Oxo Chain Cluster
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Titanium(IV)-based metal-organic frameworks (Ti-MOFs) have received significant attention in recent years due to their numerous photocatalytic applications. We herein prepare the single-crystalline Ti-carboxylate MOF (DGIST-1) composed of an unprecedented Ti-oxo chain cluster and the porphyrinic ligand, TCPP (tetrakis(4-carboxyphenyl)porphyrin). Preformed Ti-oxo clusters were used as Ti4+ sources to avoid the spontaneous hydrolysis and condensation reactions of traditional Ti-alkoxide precursors, thus, enabling the formation of the highly crystalline Ti-MOF. The successfully activated DGIST-1 exhibited a higher surface area (i.e., 1957.3 m2 g?1) than previously reported Ti-MOFs due to its high crystallinity. Furthermore, the visible-light-responsive photocatalytic activity of DGIST-1 was confirmed by the simultaneous generation of singlet oxygen (1O2) and superoxide (.O2?) species, in addition to the highly efficient and selective oxidation of benzyl alcohol to benzaldehyde.
- Keum, Yesub,Park, Seonghun,Chen, Ying-Pin,Park, Jinhee
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- The photochemistry of o-benzylbenzophenone: A pericyclic cornucopia
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UV irradiation of the title compound produces cis-1,2- diphenylbenzocyclobutenol quantitatively. While stable at temperatures below 0°, at room temperature it establishes a high enough equilibrium population of its EE o-xylylenol precursor to undergo slow reversion to ketone and rapid reaction with maleic anhydride or oxygen, as well as photoinduced cyclization to the trans cyclobutenol.
- Sobczak, Martin,Wagner, Peter J.
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- N,N′-bicarbazole-benzothiadiazole-based conjugated porous organic polymer for reactive oxygen species generation in live cells
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A π-conjugated porous organic polymer (BCzBz) was fabricated employingN,N′-bicarbazole and benzothiadiazole as molecular building units exhibiting broad visible light absorption. The photostable, water-dispersible, and cytocompatible BCzBz was demonstrated as an efficient probe for intracellular reactive oxygen species generation under photoirradiation.
- Behera, Biswajit,Giri, Arkaprabha,Kundu, Subhankar,Patra, Abhijit,Saha, Nitu
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- Self-Assembled PtII8Metallosupramolecular Tubular Cage as Dual Warhead Antibacterial Agent in Water
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Development of photosensitizer-based self-assembled metallosupramolecular architectures with important applications is an emerging trend in supramolecular chemistry. In this study, we report a new benzothiadiazole-based tetra-pyridyl ligand (L), which upon self-assembly with a cis-block 90° Pt(II) acceptor generated an unprecedented tetrafacial Pt(II)8 photoactive tubular molecular cage (PMB1). This cage could bring an extraordinary photosensitizer, benzothiadiazole, into water which is otherwise insoluble. PMB1 is fluorescent and shows photogeneration of singlet oxygen in an aqueous medium. These features make PMB1 a potent antimicrobial agent in water in both the presence and absence of light. In comparison to its building blocks and water-soluble alkylated charged ligand ([LMe4][4NO3]), the cage shows much enhanced photoinduced antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) as a representative of Gram-positive bacteria and Pseudomonas aeruginosa (PA) as a representative of Gram-negative bacteria. PMB1 is successful at inactivating the bacterial growth via both photoactivation of molecular oxygen and membrane depolarization mechanisms, thus proving to be a dual warhead. Inactivation of bacteria in water using such a supramolecular architecture is noteworthy and can shed light on the generation of new antimicrobial supramolecular systems.
- Bhattacharyya, Soumalya,De, Mrinmoy,Mukherjee, Partha Sarathi,Sahoo, Jagabandhu,Venkateswarulu, Mangili,Zangrando, Ennio
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- Kinetic and mechanistic aspects of solid state, nanostructured porphyrin diacid photosensitizers in photooxidation of sulfides
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In continuation of our studies on the photocatalytic performance of porphyrin diacids, the kinetics and mechanisms of the photooxidation of para-substituted phenyl methyl sulfides (para X = H, CH3, OCH3, Cl, and F) catalyzed by a series of meso-tetra(aryl)porphyrins (aryl = phenyl, 2-chlorophenyl, 2-methylphenyl, 4-chlorophenyl, 4-methylphenyl and 4-methoxyphenyl) immobilized on Amberlyst 15 nanostructures (nanoAmb), H2T(2 or 4-X)PP@nanoAmb, are reported. The immobilization of porphyrins on the polymer was confirmed by diffuse reflectance UV-vis spectroscopy and EDX analysis. While little or no catalyst degradation was observed for a reaction time of ca. 3 h, the electron-deficient porphyrins (pseudo-first-order rate constants, kobs = 0.0049-0.012 min-1) showed faster second-order kinetics than the electron-rich ones (kobs = 2.30 × 10-5-9.92 × 10-4 min-1). The order of photocatalytic activity of the porphyrins approximately correlates with the singlet oxygen quantum yield (φΔ) of the photosensitizers. Diffuse reflectance UV-vis spectra of the immobilized porphyrins demonstrated a large red shift of the Soret and Q bands of the porphyrins which was more dominant in the case of H2T(4-OMe)PP. The weak overlap between the emission spectrum of the light source and the absorption spectrum of the latter was used to explain the low photocatalytic activity of H2T(4-OMe)PP@nanoAmb. The observation of a slope (ρ) of -2.80 for the oxidation of methyl phenyl sulfide and para-substituted phenyl methyl sulfides is in accord with the involvement of an electrophilic oxidation mechanism mediated by singlet oxygen species. H2TPP@naoAmb was recovered and reused at least five times without significant loss of the catalytic activity and detectable catalyst degradation, giving a turnover number of 5 × 5000 for five successive reactions. The catalyst was successfully used for large-scale (up to 6.6 mmol of sulfide per batch, in a 1:10000 catalyst-to-sulfide molar ratio) photooxidation of a wide range of sulfides to the corresponding sulfoxide in a water/acetonitrile solvent mixture.
- Nasrollahi, Rahele,Heydari-Turkmani, Akram,Zakavi, Saeed
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- Investigation on Optical and Biological Properties of 2-(4-Dimethylaminophenyl)benzothiazole Based Cycloplatinated Complexes
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The optical and biological properties of 2-(4-dimethylaminophenyl)benzothiazole cycloplatinated complexes featuring bioactive ligands ([{Pt(Me2N-pbt)(C6F5)}L] [L=Me2N-pbtH 1, p-dpbH (4-(diphenylphosphino)benzoic acid) 2, o-dpbH (2-(diphenylphosphino)benzoic acid) 3), [Pt(Me2N-pbt)(o-dpb)] 4, [{Pt(Me2N-pbt)(C6F5)}2(μ-PRnP)] [PR4P=O(CH2CH2OC(O)C6H4PPh2)2 5, PR12P=O{(CH2CH2O)3C(O)C6H4PPh2}2 6] are presented. Complexes 1–6 display 1ILCT and metal-perturbed 3ILCT dual emissions. The ratio between both bands is excitation dependent, accomplishing warm-white emissions for 2, 5 and 6. The phosphorescent emission is lost in aerated solutions owing to photoinduced electron transfer to 3O2 and the formation of 1O2, as confirmed in complexes 2 and 4. They also exhibit photoinduced phosphorescence enhancement in non-degassed DMSO due to local oxidation of DMSO by sensitized 1O2, which causes a local degassing. Me2N-pbtH and the complexes specifically accumulate in the Golgi apparatus, although only 2, 3 and 6 were active against A549 and HeLa cancer cell lines, 6 being highly selective in respect to nontumoral cells. The potential photodynamic property of these complexes was demonstrated with complex 4.
- Lara, Rebeca,Millán, Gonzalo,Moreno, M. Teresa,Lalinde, Elena,Alfaro-Arnedo, Elvira,López, Icíar P.,Larráyoz, Ignacio M.,Pichel, José G.
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- Generation of singlet oxygen from ozone catalysed by phosphinoferrocenes
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A novel chemical source of singlet oxygen based on the conversion of ozone by 1,1′-bis(triphenylphosphino)ferrocene as catalyst was developed into a feasible method for a preperative scale. This is, to our best knowledge, the first application of substituted ferrocenes as oxidation catalysts. Springer-Verlag 2004.
- Jary, Walther G.,Ganglberger, Thorsten,Poechlauer, Peter,Falk, Heinz
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- The development of 1,3-diphenylisobenzofuran as a highly selective probe for the detection and quantitative determination of hydrogen peroxide
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1,3-Diphenylisobenzofuran (DPBF) has been developed as a selective probe for the detection and quantitative determination of hydrogen peroxide in samples containing different reactive nitrogen and oxygen species (RNOS). DPBF is a fluorescent probe which, for almost 20 years, was believed to react in a highly specific manner toward some reactive oxygen species (ROS) such as singlet oxygen and hydroxy, alkyloxy or alkylperoxy radicals. Under the action of these individuals DPBF has been rapidly transformed to 1,2-dibenzoylbenzene (DBB). In order to check if DPBF can act as a unique indicator of the total amount of different RNOS, as well as oxidative stress caused by an overproduction of these individuals, a series of experiments was carried out, in which DPBF reacted with peroxynitrite anion, superoxide anion, hydrogen peroxide, hypochlorite anion, and anions commonly present under biological conditions, namely nitrite and nitrate. In all cases, except for hydrogen peroxide, the product of the reaction is DBB. Only under the action of H2O2 9-hydroxyanthracen-10(9H)-one (oxanthrone) is formed. This product has been identified with the use of fluorescence spectroscopy, NMR spectroscopy, high performance liquid chromatography coupled with mass spectrometry, infrared spectroscopy, elemental analysis, and cyclic voltammetry (CV). A linear relationship was found between a decrease in the fluorescence intensity of DPBF and the concentration of hydrogen peroxide in the range of concentrations of 0.196–3.941 mM. DPBF responds to hydrogen peroxide in a very specific way with the limits of detection and quantitation of 88 and 122.8 μM, respectively. The kinetics of the reaction between DBBF and H2O2 was also studied.
- ?amoj?, Krzysztof,Zdrowowicz, Magdalena,Rudnicki-Velasquez, Pawe? B?a?ej,Krzymiński, Karol,Zaborowski, Bart?omiej,Niedzia?kowski, Pawe?,Jacewicz, Dagmara,Chmurzyński, Lech
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- Determination of the quantum yield of singlet oxygen sensitized by halogenated boron difluoride dipyrromethenes
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The spectral–luminescent, photophysical, and photochemical properties of dichloro-, dibromo-, and diiodo-derivatives of boron dipyrromethenate (BODIPY) have been studied, as well as the feasibility of generating singlet oxygen (1O2) via its photosensitization by the dihalogenated derivatives of BF2 dipyrromethene in solutions. Quantum yields of singlet oxygen have been determined using 1,3-diphenylisobenzofuran as the 1O2 trap. The lowest fluorescence quantum yields have been shown to correspond to the maximum yields of singlet oxygen. It has been found that the best 1O2 photosensitizer among the three test dihalotetraphenylaza- BODIPY is dibromotetraphenylaza-BODIPY, which in addition possesses the highest photostability. Diiodotetramethyl-BODIPY results in the singlet oxygen yield close to unity, but it has significantly lower photostability. The yield of singlet oxygen is affected by the solvent. Dibromtetraphenylaza-BODIPY and diiodotetramethyl-BODIPY may find use as a medium in photodynamic therapy and photocatalysis of oxidation reactions.
- Kuznetsova,Aksenova, Iu. V.,Bashkirtsev,Shulev,Antina,Berezin,Bumagina
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- Synthesis, spectroscopic properties and photodynamic activity of a fulleropyrrolidine bearing a basic amino group and its dicationic analog against Staphylococcus aureus
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N-Methyl-2-[4-(3-N,N-dimethylaminopropoxy)phenyl]fulleropyrrolidine (MPC60) was synthesized by 1,3-dipolar cycloaddition reaction of 4-(3-N,N-dimethylaminopropoxy)benzaldehyde, N-methylglycine and fullerene C60 in 43% yield. The amine groups of MPC60 were methylated with dimethyl sulfate to obtain a dicationic fullerene DPC602+ in 96 % yield. Absorption spectra of these fullerenes in N,N-dimethylformamide (DMF) and toluene/sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/water reverse micelles showed strong absorptions in the UV region, with a peak at 430 nm and broader range of absorption up to 710 nm. Fluorescence quantum yields of about 10-4 were calculated for these compounds in DMF. A higher singlet molecular oxygen, O2(1Δg), generation was found for MPC60 than DPC602+ in DMF. The photodynamic activity of these photosensitizers remained high in a simple biomimetic AOT system. Also, the formation of superoxide anion radical induced by MPC60 and DPC602+ was detected in presence of NADH. Decomposition of l-tryptophan in DMF mediated by both fullerenes indicated a possible contribution of type I photoprocess. Photosensitized inactivation of Staphylococcus aureus was investigated using different conditions. Cell suspensions of 108 cells/mL incubated with 0.5 μM fullerene and irradiated for 30 min exhibited a 4.4 and 5.0 log decrease of cell survival by MPC60 and DPC602+, respectively. Therefore, these fullerene derivatives can be used as effective photosensitizers for the photodynamic inactivation of S. aureus cells.
- Agazzi, Maximiliano L.,Spesia, Mariana B.,Gsponer, Natalia S.,Milanesio, M. Elisa,Durantini, Edgardo N.
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- Trifluoromethanesulfonic acid catalyzed novel friedel-crafts acylation of aromatics with methyl benzoate
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Methyl benzoate, protolytically activated by superacidic trifluoromethanesulfonic acid, reacts with aromatic compounds to give benzophenone derivatives in good to excellent yields (70-93%). Even highly deactivated nitrobenzene as well as benzotrifluoride
- Hwang, Je Pil,Surya Prakash,Olah, George A.
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- Synthesis of aza-BODIPY dyes bearing the naphthyl groups at 1,7-positions and application for singlet oxygen generation
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Using 2-vinylnaphthalene, aza-BODIPYs with the naphthyl groups at 1,7-positions were prepared and their photophysical properties were characterized. Due to attachment of the naphthyl groups at 1,7-positions, aza-BODIPYs show long-wavelength absorption and emission in the near-infrared region. The singlet oxygen generation of the dibromo substituted aza-BODIPY with the naphthyl groups at 1,7-positions as a photosensitizer was more effective than that of the corresponding aza-BODIPY with the phenyl groups at 1,7-positions. No photobleaching of the naphthyl-containing aza-BODIPY was observed and such NIR aza-BODIPY could be used for the singlet oxygen generation.
- Jiang, Xindong,Zhang, Tingjiang,Sun, Changliang,Meng, Yanqiu,Xiao, Linjiu
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- Monofunctional BODIPY-Appended Imidazoplatin for Cellular Imaging and Mitochondria-Targeted Photocytotoxicity
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Monofunctional platinum(II) complexes of formulation cis-[Pt(NH3)2(L)Cl](NO3), where L is an imidazole base conjugated to 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) with emissive (L1 in 1) and nonemissive (L2 in 2) moieties were prepared and characterized, and their singlet oxygen-mediated photoinduced cytotoxicity was studied. The 1-methylimidazole (1-MeIm) complex 3 was prepared as a control and for structural characterization by X-ray crystallography. Complexes 1 and 2 showed strong visible absorption bands at 500 nm (? = 2.7 × 104 M-1 cm-1) and 540 nm (1.4 × 104 M-1 cm-1). Complex 1 is emissive with a band at 510 nm (ψ F = 0.09) in 1% dimethyl sulfoxide/Dulbecco's Modified Eagle's Medium (pH 7.2). Singlet oxygen generation upon photoirradiation with visible light (400-700 nm) was evidenced from 1,3-diphenylisobenzofuran titration experiments showing significant photosensitizing ability of the BODIPY complexes. Both 1 and 2 were remarkably photocytotoxic in visible light (400-700 nm, 10 J cm-2) in skin keratinocyte HaCaT and breast cancer MCF-7 cells giving IC50 values in nanomolar concentration. The complexes were, however, essentially nontoxic to the cells in the dark (IC50 > 80 μM). Complex 2 having a diiodo-BODIPY unit is nonemissive but an efficient photosensitizer with high singlet oxygen generation ability in visible light (400-700 nm). Confocal microscopy using the emissive complex 1 showed significant mitochondrial localization of the complex. Cell death via apoptotic pathway was observed from the Annexin-V-FITC/PI assay. The formation of Pt-DNA adducts was evidenced from the binding experiments of the complexes 1 and 2 with 9-ethylguanine as a model nucleobase from 1H NMR and mass spectral studies.
- Raza, Md Kausar,Gautam, Srishti,Garai, Aditya,Mitra, Koushambi,Kondaiah, Paturu,Chakravarty, Akhil R.
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- Distinct photodynamics of κ-N and κ-C pseudoisomeric iron(ii) complexes
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Two closely related FeIIcomplexes with 2,6-bis(1-ethyl-1H-1,2,3-triazol-4yl)pyridine and 2,6-bis(1,2,3-triazol-5-ylidene)pyridine ligands are presented to gain new insights into the photophysics of bis(tridentate) iron(ii) complexes. The [Fe(N^N^N)2]2+pseudoisomer sensitizes singlet oxygen through a MC state with nanosecond lifetime after MLCT excitation, while the bis(tridentate) [Fe(C^N^C)2]2+pseudoisomer possesses a similar3MLCT lifetime as the tris(bidentate) [Fe(C^C)2(N^N)]2+complexes with four mesoionic carbenes.
- Dierks, Philipp,Kruse, Ayla,Bokareva, Olga S.,Al-Marri, Mohammed J.,Kalmbach, Jens,Baltrun, Marc,Neuba, Adam,Schoch, Roland,Hohloch, Stephan,Heinze, Katja,Seitz, Michael,Kühn, Oliver,Lochbrunner, Stefan,Bauer, Matthias
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- Light-Harvesting Antenna and Proton-Activated Photodynamic Effect of a Novel BODIPY?Fullerene C60 Dyad as Potential Antimicrobial Agent
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A covalently linked BODIPY?fullerene C60 dyad (BDP?C60) was synthesized as a two-segment structure, which consists of a visible light-harvesting antenna attached to an energy or electron acceptor moiety. This structure was designed to improve the photodynamic action of fullerene C60 to inactivate bacteria. The absorption spectrum of BDP?C60 was found to be a superposition of the spectra of its constitutional moieties, whereas the fluorescence emission of the BODIPY unit was strongly quenched by the fullerene C60. Spectroscopic, calculations, and redox studies indicate a competence between photoinduced energy and electron transfer. Protonating the dimethylaminophenyl substituent through addition of an acidic medium led to a substantial increase in the fluorescence emission, triplet excited state formation, and singlet molecular oxygen production. At physiological pH, photosensitized inactivation of Staphylococcus aureus mediated by 1 μM BDP?C60 exhibited a 4.5 log decrease of cell survival (>99.997 %) after 15 min irradiation. A similar result was obtained with Escherichia coli using 30 min irradiation. Moreover, proton-activated photodynamic action of BDP?C60 turned this dyad into a highly effective photosensitizer to eradicate E. coli. Therefore, BDP?C60 is an interesting photosensitizing structure in which the light-harvesting antenna effect of the BODIPY unit combined with the protonation of dimethylaminophenyl group can be used to improve the photoinactivation of bacteria.
- Agazzi, Maximiliano L.,Durantini, Javier E.,Gsponer, Natalia S.,Durantini, Andrés M.,Bertolotti, Sonia G.,Durantini, Edgardo N.
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- Kinetically labile ruthenium(ii) complexes of terpyridines and saccharin: effect of substituents on photoactivity, solvation kinetics, and photocytotoxicity
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Herein, we designed six kinetically labile ruthenium(ii) complexes containing saccharin (sac) and 4′-substituted-2,2′:6′,2′′-terpyridines (R-tpy),viz. trans-[Ru(sac)2(H2O)3(dmso-S)] (1) and [RuII(R-tpy)(sac)2(X)] [X = solvent molecule] (2-6). We intentionally kept the labile hydrolysable Ru-X bonds that were potentially activatedviasolvent-exchange reactions. This strategy generates a coordinative vacancy that allows further binding with potential biological targets. To gain insight into the electronic effects of ancillary ligands on Ru-X ligand-exchange kinetics or photoreactions, we have used a series of substituted terpyridines (R-tpy) and studied their solvation kinetics. The ternary complexes were also studied for their potential utility in Ru-assisted photoactivated chemotherapy (PACT) synergized with release of saccharin as a highly selective carbonic anhydrase IX (CA-IX) inhibitor, over-expressed in hypoxic tumors. The ternary complexes exhibit distorted octahedral geometry around Ru(ii) from two monodentatetransoidalsaccharin in the axial position, and tridentate terpyridines and labile solvent molecules at the basal plane (2-6). We studied their speciation, solvation kinetics, and photoreactivity in the presence of green LED light (λirr= 530 nm). All the complexes are relatively labile and undergo solvation in coordinating solvents (e.g.DMSO/DMF). The complexes undergo the ligand-substitution reaction, and their speciation and kinetics were studied by UV-Vis, ESI-MS,1H-NMR, and structural analysis. We also attempted to assess the effect of various substituents on the ancillary terpyridine ligand (R-tpy) in photo-reactivity and ligand-exchange reactions. The photo-induced absorption and emission measurements suggested dissociation of the saccharin from the Ru-center supporting PACT pathways. The complexes display a significant binding affinity with CT-DNA (Kb~ 104-105M?1) and bovine serum albumin (BSA) (KBSA~ 105M?1). Cytotoxicity was studied in the dark and the presence of low energy UV-A light (365 nm) in cervical cancer cells (HeLa) and breast cancer cells (MCF7). Photoirradiation of the complexes induces the generation of reactive oxygen species (ROS) assessed using 1,3-diphenylisobenzofuran (DPBF) and intracellular DCFDA assays. The complexes are sufficiently internalized in cancer cells throughout the cytoplasm and nucleus and induce apoptosis as studied by staining with dual dyes using confocal microscopy.
- Kumar, Priyaranjan,Pakira, Sandip,Patra, Ashis K.,Saren, Sanjoy,Singh, Prerana,Sivakumar, Sri
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- Consecutive cross-coupling of o-phenylenedizinc compound with acyl and/or aryl halides in the presence of Pd(0)-tris(2,4,6- trimethoxyphenyl)phosphine
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Consecutive cross-coupling of an o-phenylenedizinc compound 1 with two different acyl or aryl halides or acyl and aryl halides was accomplished in one pot by the catalysis of Pd(0)-tris(2,4,6-trimethoxyphenyl)phosphine to yield a variety of functionalized unsymmetrical 1,2-disubstituted benzenes in good yields. (C) 2000 Elsevier Science Ltd.
- Saiga, Akihiro,Hossain, Kabir M.,Takagi, Kentaro
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- The anti-cancer potency of photodynamic therapy of a novel chlorin derivative Amidochlorin p6 (ACP)
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Photodynamic therapy (PDT) is a minimally invasive method in cancer treatment and has attracted considerable attention recently. In this paper, we have performed a detailed study of photodynamic activity of a chlorophyllous derivative, Amidochlorin p6 (ACP), and evaluated its potential as a photosensitizer in PDT. The singlet oxygen quantum yield (ΦΔ), the photoreaction mechanisms in PDT, the anti-photobleaching ability in phosphate buffer saline (PBS), the photocytotoxicity and dark toxicity against HeLa cells, cellular uptake and the influence on the expression of survivin and cyclin-dependent kinase (CDK2), were all investigated. The title compound showed significant photocytotoxicity and negligible toxicity in dark, and remarkable photostability. Moreover, ACP could be uptaken by HeLa cells successfully at 20 min leading to damage of cancer cells under light, during which Type I and Type II photodynamic reactions occurred simultaneously on HeLa cells in PDT treatment, and the influence of Type I (the generation of hydroxyl radicals) is slightly larger than Type II (the generation of singlet oxygen). In addition, real-time fluorescent quantitative PCR (RT-qPCR) suggested that ACP could significantly regulate the expression of survivin, which partly explained why ACP could induce the HeLa cell apoptosis and accelerate cell death.
- Zhang, Hongyue,Li, Wenting,Tan, Guanghui,Ding, Guohua,Wang, Zhiqiang,Jin, Yingxue
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- Phosphorescent biscyclometallated iridium(iii) ethylenediamine complexes functionalised with polar ester or carboxylate groups as bioimaging and visualisation reagents
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We report the synthesis, characterisation and photophysical properties of new phosphorescent biscyclometallated iridium(iii) ethylenediamine (en) complexes functionalised with polar ester or carboxylate groups [Ir(N^C)2(en)]n(X) (n = +1, X = Cl-, HN^C = methyl 4-(2-pyridyl)benzoate Hppy-COOMe (1a), methyl 2-phenyl-4-quinolinecarboxylate Hpq-COOMe (2a); n = -1, X = Li+, HN^C = 4-(2-pyridyl)benzoate Hppy-COO- (1b), 2-phenyl-4-quinolinecarboxylate Hpq-COO- (2b)). In aqueous solutions, the carboxylate complexes 1b and 2b displayed emission quenching (ca. 7 and 74 fold, respectively) and lifetime shortening upon protonation, and their pKa values were determined to be 5.13 and 3.46, respectively. The pq complexes 2a and 2b exhibited hypsochromic shifts in their emission maxima and a significant increase in emission intensity (ca. 84 and 15 fold, respectively) upon nonspecific binding to the protein bovine serum albumin (BSA). Inductively coupled plasma-mass spectroscopy (ICP-MS) and laser-scanning confocal microscopy (LSCM) results revealed that the ester complexes 1a and 2a were efficiently internalised by the human cervix epithelioid carcinoma (HeLa) cells through energy-requiring pathways and subsequently localised in endosomes and mitochondria, respectively. They showed good biocompatibility in the dark, but became significantly cytotoxic upon photoirradiation due to the generation of singlet oxygen. In contrast, in aqueous solutions of physiological pH, the carboxylate complexes 1b and 2b existed as the anionic form and hardly entered cells due to limited membrane permeability, as evidenced by the intense emission surrounding the plasma membrane of the cells. They showed negligible cytotoxicity and the cell viability remained over 95% for an incubation period of 24 hours. In view of the low cytotoxicity and strongly emissive nature of the hydrophilic ppy-COO- complex 1b in an aqueous medium, the potential application of the complex as a visualisation reagent has been demonstrated using zebrafish (Danio rerio) as an animal model. This journal is
- Tang, Tommy Siu-Ming,Leung, Kam-Keung,Louie, Man-Wai,Liu, Hua-Wei,Cheng, Shuk Han,Lo, Kenneth Kam-Wing
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- Photocatalytic coatings based on a zinc(ii) phthalocyanine derivative immobilized on nanoporous gold leafs with various pore sizes
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A series of singlet oxygen sensitizing hybrid materials is reported consisting of a zinc(ii) phthalocyanine (ZnPc) derivative immobilized on nanoporous gold leafs (npAu) with various pore sizes. The resulting photocatalytic coatings exhibit a thickness of around 100 nm and pore sizes between 9-50 nm. Herein, we report the synthesis and characterization of those hybrid materials which were synthesized by functionalization of npAu leafs by an azide terminated alkanethiol self-assembled monolayer (SAM) and subsequent copper catalyzed azide-alkyne cycloaddition (CuAAC). The characterization of the samples morphology included scanning electron microscopy (SEM), UV-Vis spectroscopy as well as energy dispersive X-ray spectroscopy (EDX). The morphology-reactivity relationship was investigated employing the hybrid photocatalysts in the photooxidation of diphenylisobenzofuran (DPBF) as selective singlet oxygen quencher. An increasing photocatalytic activity was found for smaller pore sizes up to 15 nm, due to the gain in specific surface area concomitant with an increasing amount of immobilized photosensitizer, completely dominating the effect of the higher spectral overlap caused by the shift of the plasmon resonance of npAu, until mass transport and diffusion limitation gets predominant for pore sizes below 15 nm.
- Steinebrunner, David,Schnurpfeil, Günter,W?hrle, Dieter,Wittstock, Arne
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- Sulfanyl porphyrazines with morpholinylethyl periphery—synthesis, electrochemistry, and photocatalytic studies after deposition on titanium(Iv) oxide p25 nanoparticles
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The syntheses, spectral UV–Vis, NMR, and electrochemical as well as photocatalytic properties of novel magnesium(II) and zinc(II) symmetrical sulfanyl porphyrazines with 2-(morpholin-4-yl)ethylsulfanyl peripheral substituents are presented. Both porphyrazine derivatives were synthe-sized in cyclotetramerization reactions and subsequently embedded on the surface of commercially available P25 titanium(IV) oxide nanoparticles. The obtained macrocyclic compounds were broadly characterized by ESI MS spectrometry, 1D and 2D NMR techniques, UV–Vis spectroscopy, and subjected to electrochemical studies. Both hybrid materials, consisting of porphyrazine derivatives embedded on the titanium(IV) oxide nanoparticles’ surface, were characterized in terms of particle size and distribution. Next, they were subjected to photocatalytic studies with 1,3-diphenylisobenzofuran, a known singlet oxygen quencher. The applicability of the obtained hybrid material consisting of titanium(IV) oxide P25 nanoparticles and magnesium(II) porphyrazine derivative was assessed in photocatalytic studies with selected active pharmaceutical ingredients, such as diclofenac sodium salt and ibuprofen.
- Goslinski, Tomasz,Koczorowski, Tomasz,Szczolko, Wojciech,Teubert, Anna
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- Squaraines bearing halogenated moieties as anticancer photosensitizers: Synthesis, characterization and biological evaluation
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We report the synthesis and characterization of a series of symmetrical indolenine-based squaraine dyes along with the evaluation of their singlet oxygen generation efficiency. The photodynamic activity of these new photosensitizers has been evaluated on a human tumor fibrosarcoma (HT-1080) cell line. The cytotoxicity increased over time and is induced by the photoactivation of bromo (Br-C4) and iodio (I-C4) long carbon chain squaraine dyes and the consequent increase in reactive oxygen species (ROS) production (p 0.001), which leads to necrosis 6 h after treatment. Induction of cytochrome c release, DNA damage and up-regulation of GPX1, NQO1 and SOD2 mRNA gene expression after PDT were investigated.
- Serpe, Loredana,Ellena, Silvano,Barbero, Nadia,Foglietta, Federica,Prandini, Federica,Gallo, Maria Pia,Levi, Renzo,Barolo, Claudia,Canaparo, Roberto,Visentin, Sonja
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- Synthesis of o-arylenedizinc compounds from 1-Iodo-2- trifluoromethylsulfonyloxybenzenes and Zinc Powder and their synthetic application
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1-Iodo-2-trifluoromethylsulfonyloxybenzenes readily reacted with Zn powder to yield o-arylenedizinc compounds, efficient synthetic equivalents of o-arylene dianions in Pd(0)-catalyzed cross-coupling reactions, wherein the novel insertion of Zn powder into the C-O bond of aryl triflates took place.
- Amano, Masayuki,Saiga, Akihiro,Ikegami, Ryo,Ogata, Takeshi,Takagi, Kentaro
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- High-yielding synthesis and full spectroscopic characterization of 5,6:11,12-di-o-phenylenetetracene and its synthesis intermediates
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Herein we present a synthetic gram-scale route to 5,6:11,12-di-o-phenylenetetracene (DOPT, 8), which is a member of the class of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs). Full analytical characterization of the title compound was carried out by IR, Raman, UV/Vis, and high-field 1H NMR spectroscopy, as well as by mass spectrometry. A unique double-elimination of phenylide moieties, as the key reaction step, gave DOPT for the first time in high purity and in an isolated yield of >70 %. Re-aromatization of the annulated π-ring system occurred following the reductive elimination of the two phenyl groups from the DOPT precursor. Two alternative reaction pathways for this process are discussed. The synthetic method described herein may allow development of the chemistry of the title compound further, for example, to investigate the organometallic chemistry of DOPT as well as its semiconducting behavior in organic electronics. Diels-Alder chemistry has allowed the high-yielding synthesis of the carbon framework of the aromatic hydrocarbon 5,6:11,12-di-o-phenylenetetracene (DOPT). All the reaction intermediates have been fully characterized for the first time. A final unprecedented re-aromatization sequence employing a two-fold reductive dephenylation yielded crystalline, blue DOPT in gram-scale quantities.
- Wombacher, Tobias,Foro, Sabine,Schneider, J?rg J.
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- Unusually Large Singlet Oxygen (1O2) Production by Very Weakly Emissive Pyrene-Functionalized Iridium(III) Complex: Interplay between Excited 3ILCT/3IL and 3MLCT States
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The photophysical properties of a few Ir(III) and Rh(III) complexes have been attempted to be correlated (1–4) with their 1O2 generation efficiencies. A very weakly emissive pyrene-functionalized Ir(III) complex (1) produces 1O2 more efficiently than the other more emissive Ir(III) complexes. All of them have excited triplet state lifetimes (τT) in the microsecond regime. However, the pyrene-functionalized Ir(III) complex possesses the largest τT and has reasonable HOMO (highest occupied molecular orbital) energy (1O2 production. 1–4 emit mostly from the 3MLCT state. The lowest triplet emissive state of 3 and 4 is the 3MLCT state while it is the 3ILCT/3IL state for 1 which is mostly non-emissive. However, the large excited state lifetime and the small energy gap between the 3ILCT/3IL states and the ground electronic state for complex 1 facilitates efficient energy transfer to molecular 3O2 producing 1O2.
- Seth, Sourav Kanti,Purkayastha, Pradipta
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- Molecular complexes and main-chain organometallic polymers based on Janus bis(carbenes) fused to metalloporphyrins
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Janus bis(N-heterocyclic carbenes) composed of a porphyrin core with two N-heterocyclic carbene (NHC) heads fused to opposite pyrroles were used as bridging ligands for the preparation of metal complexes. We first focused our attention on the synthesis of gold(i) chloride complexes [(NHC)AuCl] and investigated the substitution of the chloride ligand by acetylides to obtain the corresponding [(NHC)AuC?CR] complexes. Polyacetylides were then used to obtain molecular multiporphyrinic systems with porphyrins fused to only one NHC ligand, while main-chain organometallic polymers (MCOPs) were obtained when using Janus porphyrin bis(NHCs). Interestingly, MCOPs incorporating zinc(ii) porphyrins proved to be efficient as heterogeneous photocatalysts for the generation of singlet oxygen upon visible light irradiation.
- Clément, Sébastien,Laurencin, Danielle,Lebrun, Aurélien,Lo, Mamadou,Longevial, Jean-Fran?ois,Richeter, Sébastien
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- Post-synthetically elaborated BODIPY-based porous organic polymers (POPs) for the photochemical detoxification of a sulfur mustard simulant
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Designing new materials for the effective detoxification of chemical warfare agents (CWAs) is of current interest given the recent use of CWAs. Although halogenated borondipyrromethene derivatives (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene or BDP or BODIPY) at the 2 and 6 positions have been extensively explored as efficient photosensitizers for generating singlet oxygen (1 O2) in homogeneous media, their utilization in the design of porous organic polymers (POPs) has remained elusive due to the difficulty of controlling polymerization processes through cross-coupling synthesis pathways. Our approach to overcome these difficulties and prepare halogenated BODIPYbased porous organic polymers (X-BDP-POP where X = Br or I) represents an attractive alternative through post-synthesis modification (PSM) of the parent hydrogenated polymer. Upon synthesis of both the parent polymer, H-BDP-POP, and its post-synthetically modified derivatives, Br-BDP-POP and I-BDP-POP, the BET surface areas of all POPs have been measured and found to be 640, 430, and 400 m2 g-1, respectively. In addition, the insertion of heavy halogen atoms at the 2 and 6 positions of the BODIPY unit leads to the quenching of fluorescence (both polymer and solution-phase monomer forms) and the enhancement of phosphorescence (particularly for the iodo versions of the polymers and monomers), as a result of efficient intersystem crossing. The heterogeneous photocatalytic activities of both the parent POP and its derivatives for the detoxification of the sulfur mustard simulant, 2-chloroethyl ethyl sulfide (CEES), have been examined; the results show a significant enhancement in the generation of singlet oxygen (1 O2). Both the bromination and iodination of H-BDP-POP served to shorten by 5-fold of the time needed for the selective and catalytic photo-oxidation of CEES to 2-chloroethyl ethyl sulfoxide (CEESO).
- Atilgan, Ahmet,Beldjoudi, Yassine,Cetin, Furkan M.,Cetin, M. Mustafa,Deria, Pravas,Farha, Omar K.,Hupp, Joseph T.,Islamoglu, Timur,Liu, Jian,Stern, Charlotte L.,Stoddart, J. Fraser,Yu, Jierui
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- Kinetics of the reaction between 1,3-diphenylisobenzofuran and nitrogen dioxide studied by steady-state fluorescence
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1,3-Diphenylisobenzofuran (DPBF) is a fluorescent molecule which is believed to react highly specifically toward reactive oxygen species such as singlet oxygen (1O2), hydroxy (HO·), alkyloxy (RO·), and alkylperoxy (ROO·) radicals. In all cases the reaction product is 1,2-dibenzoylbenzene. In order to prove that DPBF gives the same product in contact with reactive nitrogen species, its reaction with nitrogen dioxide radical has been studied in 2,2,4-trimethylpentane using the steady-state fluorescence method and mass spectrometry. The progress of the studied reaction was measured by observation of changes in fluorescence intensity of DPBF after addition of nitrogen dioxide (NO2). The rate constants of DPBF fluorescence decay affected by NO2 have been determined. Experiments were conducted over the temperature range of 13-37 C and for NO2 concentrations from 0.02 to 0.14 mmol dm-3. It has been found that the reaction between 1,3-diphenylisobenzofuran and nitrogen dioxide proceeds in two steps. The first step is a very rapid reaction whose rate could not be measured under established experimental conditions. The second step is slower. The reaction product was identified by registration of mass spectra. The probable reaction mechanism is proposed.
- ?amoj?, Krzysztof,Jacewicz, Dagmara,Zdrowowicz, Magdalena,Chmurzyński, Lech
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- Dually-Passivated Perovskite Solar Cells with Reduced Voltage Loss and Increased Super Oxide Resistance
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In recent years, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) has witnessed rapid progress. Nevertheless, the pervasive defects prone to non-radiative recombination and decomposition exist at the surface and the grain boundaries (GBs) of the polycrystalline perovskite films. Herein, we report a comprehensive dual-passivation (DP) strategy to effectively passivate the defects at both surface and GBs to enhance device performance and stability further. Firstly, a fluorinated perylene-tetracarboxylic diimide derivative is permeated in the perovskite metaphase during antisolvent treatment, and then a fluorinated bulky aromatic ammonium salt is introduced over the annealed perovskite. The reduction of defect density can be unambiguously proved by the superoxide species generation/quenching reaction. As a result, optimized planar PSCs demonstrate a decreased open-circuit voltages deficit from 0.47 to 0.39 V and the best efficiency of 23.80 % from photocurrent scanning with a stabilized maximum power output efficiency of 22.99 %. Without encapsulation, one typical device can maintain over 85 % of the initial efficiency after heating on a hot plate at 100 °C for 30 h under relative humidity (RH) of 70 %. When the device is aged under 30±5 % RH, over 97 % of its initial PCE is retained after 1700 h.
- Zhou, Qin,Gao, Yifeng,Cai, Chunsheng,Zhang, Zhuangzhuang,Xu, Jianbin,Yuan, Zhongyi,Gao, Peng
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- Synthesis dibromo substituted BOPHY dye for the singlet oxygen generation
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A dibromo substituted BOPHY derivative (2) was prepared and found to exhibit photo-sensitization capability. Rapid oxidation of 80% DPBF at the first 6 min was observed suggesting that 2 is a superior photo-sensitizer than methylene blue. The HOMO–LUMO band gap for the lowest energy absorption bands of the BOPHY 1 is smaller than that of PS 2, which is in good agreement with the red shift in the absorption observed between 1 and 2.
- Cui, Tian-Fang,Zhang, Jing,Jiang, Xin-Dong,Su, Ya-Jun,Sun, Chang-Liang,Zhao, Jiu-Li
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- Ortho-Phenylenedizinc(II) Compounds. Ultrasound-Promoted Synthesis from o-Diiodobenzene and Zinc Powder and Its Synthetic Application
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A facile and efficient synthetic procedure of o-phenylenedizinc(II) compound from o-diiodobenzene and zinc powder under the irradiation of ultrasound is reported.The compound was proved to be a unique reagent supplying o-phenylenedianion of high chemoselectivity.Symetrically 1,2-diaryl or diaroyl substiituted benzenes were obtained in good yields by Pd(0)-catalyzed cross-coupling of the compound with aryl halides or acyl halides.
- Takagi, Kentaro,Shimoishi, Yasuaki,Sasaki, Ken
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- Novel distyryl BODIPY-fullerene dyads: Preparation, characterization and photosensitized singlet oxygen generation efficiency
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Novel types of mono- and bis-distyryl-BODIPY-fullerene dyads, 6 and 7, were prepared by Bingel cyclopropanation. Distyryl-BODIPY derivative (3) was reacted with methyl malonyl chloride and malonyl dichloride respectively for the synthesis of compounds 4 and 5 as light-harvesting antennae that contain one and two BODIPY units. Through the Bingel cyclopropanation of these BODIPYs (4 and 5) with fullerene-C60 in the presence of CBr4 and DBU, distyryl-BODIPY-fullerene dyads 6 and 7 were obtained. All newly synthesized compounds were characterized by MALDI-MS, 1H and 13C NMR and elemental analysis. Moreover, the photophysical and photochemical properties of these heavy atom free dyads were investigated for the determination of their photosensitizer and fluorescence abilities in the near IR region to generate singlet oxygen.
- ünlü, Hasan,Okutan, Elif
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- Switching of the Triplet Excited State of Rhodamine/Naphthaleneimide Dyads: An Experimental and Theoretical Study
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Rhodamine-bromonaphthaleneimide (RB-NI) and rhodamine-bromonaphthalenediimide (RB-NDI) dyads were prepared for switching of the triplet excited states. Bromo-NI or bromo-NDI parts in the dyads are the spin converters, i.e., the triplet state producing modules, whereas the RB unit is the acid-activatable electron donor/energy acceptor. NI and NDI absorb at 359 and 541 nm, and the T1 state energy levels are 2.25 and 1.64 eV, respectively. RB undertakes the reversible spirolactam (RB-c) 虠 opened amide (RB-o) transformation. RB-c shows no visible light absorption, and the triplet-state energy level is ET1 = 3.36 eV. Conversely RB-o shows strong absorption at 557 nm, and ET1 is 1.73 eV. Thus, the acid-activated fluorescence-resonance-energy-transfer (FRET) competes with the ISC of NI or NDI. No triplet state was observed for the dyads with nanosecond time-resolved transient absorption spectroscopy. Upon addition of acid, strong fluorescence and long-living triplet excited states were observed. Thus, the producing of triplet state is acid-activatable. The triplet state of RB-NI is localized on RB-o part, whereas in RB-NDI the triplet state is delocalized on both the NDI and RB-o units. The ISC of spin converter was not outcompeted by RET. These studies are useful for switching of triplet excited state.
- Cui, Xiaoneng,Zhao, Jianzhang,Lou, Zhangrong,Li, Shujing,Wu, Huijian,Han, Ke-Li
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- Pd-NHC catalysed Carbonylative Suzuki coupling reaction and its application towards the synthesis of biologically active 3-aroylquinolin-4 (1H)-one and acridone scaffolds
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We have unfolded a convenient and mild protocol for the synthesis of diaryl ketones via Pd- NHC catalysed carbonylative Suzuki coupling reaction. Notably, this method offers advantages like no use of toxic CO gas, shorter reaction time, high yield, and broad substrate scope. Several sensitive functional groups (like-COMe, -COOMe, -F, -Cl, -Br, -NH2, -CN) are well tolerated in this reaction. In addition, we have also demonstrated a new efficient route for the synthesis of biologically active and pharmaceutically important 2-substituted 3-Aroylquinolin-4(1H)-ones and acridone scaffolds.
- Ghosh, Prasanjit,Ganguly, Bhaskar,Das, Sajal
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- A new Phenol Red-modified porphyrin as efficient protein photocleaving agent
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Protein affinity is of importance for porphyrins in their application in photodynamic therapy (PDT). A new Phenol Red-modified porphyrin (R-TPP) was designed and synthesized to fully take advantage of the binding character of Phenol Red towards protein. Detailed comparisons of absorption spectra, fluorescence spectra, n-octanol/water partition coefficients, 1O 2 quantum yields, as well as protein photocleaving abilities between R-TPP and its parent porphyrin Br-TPP clearly demonstrate the benefits stemming from the modification of Phenol Red. On one hand, the presence of Phenol Red moiety greatly enhances the binding affinity of R-TPP towards model proteins (bovine serum albumin and hen egg lysozyme), and therefore improves the availability of 1O2. On the other hand, the presence of Phenol Red moiety provides R-TPP with amphiphilic character, and therefore restricts aggregation and favors the generation of 1O2. As a result, R-TPP photocleaves proteins efficiently, showing promising application potential in PDT.
- Jiang, Guo-Yu,Lei, Wan-Hua,Zhou, Qian-Xiong,Hou, Yuan-Jun,Wang, Xue-Song,Zhang, Bao-Wen
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- BODIPY-vinyl dibromides as triplet sensitisers for photodynamic therapy and triplet-triplet annihilation upconversion
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We devised a new generation of halogen-based triplet sensitisers comprising geminal dibromides at the vinyl backbone of a BODIPY fluorophore. Incorporating geminal dibromides into the π-conjugation of BODIPY enhanced intersystem crossing due to the heavy atom effect, which in turn improved the extent of excited triplet states.
- Dartar, Suay,Ucuncu, Muhammed,Karakus, Erman,Hou, Yuqi,Zhao, Jianzhang,Emrullahoglu, Mustafa
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- Stereoselective Synthesis of cis-2-Ene-1,4-diones via Aerobic Oxidation of Substituted Furans Catalyzed by ABNO/HNO3
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We report a highly efficient and selective catalytic system, ABNO (9-azabicyclo-[3.3.1]nonane N-oxyl)/HNO3, for the aerobic oxidation of substituted furans to cis-2-ene-1,4-diones under mild reaction conditions using oxygen as the oxidant. The catalyst system is amenable to various substituted (mon-, di-, and tri-) furans and tolerates diverse functional groups, including cyano, nitro, naphthyl, ketone, ester, heterocycle, and even formyl groups. Based on the control and 18O-labeling experiments, the possible mechanism of the oxidation is proposed.
- Yang, Liqun,Wang, Jingyang,Wang, Yue,Li, Xiaotong,Liu, Wei,Zhang, Zhaoguo,Xie, Xiaomin
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p. 14311 - 14320
(2021/10/25)
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- Oxidative Cleavage of Indoles Mediated by Urea Hydrogen Peroxide or H2O2 in Polar Solvents
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The oxidative cleavage of indoles (Witkop oxidation) involving the use of H2O2 or urea hydrogen peroxide in combination with a polar solvent has been described. Among these solvents, 1,1,1,3,3,3-hexafluoroisopropanol (HFIP) stands out as the one affording the corresponding 2-ketoacetanilides generally in higher yields The protocol described has also enabled the oxidation of different pyrroles and furans derivatives. Furthermore, the procedure was implemented in a larger-scale and HFIP was distilled from the reaction mixture and reused (up to 4 cycles) without a significant detriment in the reaction outcome, which remarks its sustainability and applicability. (Figure presented.).
- Llopis, Natalia,Gisbert, Patricia,Baeza, Alejandro
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supporting information
p. 3245 - 3249
(2021/06/08)
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- Visible-Light-Induced Oxazoline Formations fromN-Vinyl Amides Catalyzed by an Ion-Pair Charge-Transfer Complex
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Visible-light photoredox catalysis plays an important role in various reactions which are inaccessible under typical thermal conditions. Distinctly different from common visible-light photoredox catalysis which often involves transition-metal complexes, conjugated organic dyes, or electron donor-acceptor complexes, herein, the use of ion-pair charge-transfer (IPCT) complex-induced visible-light photoredox catalytic reactions are described, wherein the cyclization-methoxylation ofN-vinyl amides in methanol was achieved under irradiation with blue LEDs. The reaction employs a heteroarenium iodide as the photocatalyst and can be extended to cyclization-alkoxylation, ?acyloxylation, and ?hydroxylation. This protocol provides an eco-friendly synthetic route to a wide range of oxazoline derivatives. Mechanistic investigations with UV-visible spectroscopy and control experiments confirm the existence of the IPCT absorption band in the visible region for the heteroarenium iodide, which is responsible for the observed reactivity.
- Sun, Rui,Yang, Xiao,Ge, Yicen,Song, Jintong,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Chen, Hua,Fu, Haiyan
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p. 11762 - 11773
(2021/09/28)
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- Auto-tandem PET and EnT photocatalysis by crude chlorophyll under visible light towards the oxidative functionalization of indoles
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Chlorophyll is the most abundant photocatalytic pigment that enables plants to absorb solar energy and convert it to energy storage molecules. Herein, we report a tandem photocatalytic approach utilizing the natural pigment chlorophyll in crude form to achieve photoinduced electron transfer (PET) and energy transfer (EnT) towards the oxidative functionalization of indoles. Redox potentials, ESR, fluorescence quenching and UV experiments have evidenced the dual catalytic activity of chlorophyll. The highlight of the study is the auto-tandem photocatalytic role of chlorophyll to enable the green oxidation of indoles using molecular oxygen as the oxidant, water as the reaction medium, and photochemical energy from the visible region of the spectrum.
- Banu, Saira,Choudhari, Shubham,Patel, Girija,Yadav, Prem P.
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supporting information
p. 3039 - 3047
(2021/05/05)
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- Epoxy platinum complex as well as preparation method and application thereof
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The invention relates to an epoxy platinum complex as well as a preparation method and application thereof, the epoxy platinum complex has a structure as shown in a formula I, the epoxy platinum complex can recognize tyrosinase through fluorescence change, experimental verification proves that the epoxy platinum complex has melanoma and breast cancer cell resisting activity, and the series of compounds can be used as antitumor drugs and can be used for preparing anti-tumor drugs. And a foundation is laid for photodynamic tumor treatment.
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Paragraph 0104-0106
(2021/03/18)
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- Charge Transfer from Donor to Acceptor in Conjugated Microporous Polymer for Enhanced Photosensitization
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Photosensitization associated with light absorption and energy/electron-transfer represents the central processes for photosynthesis. However, it's still a challenge to develop a heavy-atom-free (HAF) strategy to improve the sensitizing ability of polymeric photosensitizers. Herein, we propose a new protocol to significantly improve the photosensitization by decorating mother conjugated microporous polymer (CMP-1) with polycyclic aromatic hydrocarbons (PAHs), resulting in a series of CMPs (CMP-2–4). Systematic study reveals that covalent modification with PAHs can transfer charge to Bodipy in CMP to further facilitate both intersystem crossing and electron-hole separation, which can dramatically boost energy-/electron-transfer reactions. Remarkably, CMP-2 as a representative CMP can efficiently drive the photosynthesis of methyl phenyl sulfoxide with 92 % yield, substantially higher than that of CMP-1 (32 %). Experiments and theory calculations demonstrate the structure-property-activity relationship of these CMPs, opening a new horizon for developing HAF heterogeneous photosensitizers with highly efficient sensitizing activity by rational structure regulation at a molecular level.
- Guo, Guang-Chen,Guo, Song,Kong, Li-Hui,Lu, Tong-Bu,Peng, Yuan-Zhao,Zhang, Zhi-Ming
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supporting information
p. 22062 - 22069
(2021/08/30)
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- EFFICIENT AND SELECTIVE ROUTE FOR THE SYNTHESIS OF ALKYL 2-BENZOYLBENZOATE
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A method for preparing an alkyl 2-benzoylbenzoate comprising reacting a dialkyl phthalate with a Grignard reagent in the presence of an oxygenated solvent. The Grignard reagent may be selected from phenyl magnesium bromide, phenyl magnesium chloride, and phenyl magnesium iodide.
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Paragraph 0028
(2021/08/27)
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- Visible-light-initiated catalyst-free oxidative cleavage of (Z)-triaryl-substituted alkenes containing pyridyl motif under ambient conditions
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The catalyst-free oxidative cleavage of (Z)-triaryl-substituted alkenes bearing a pyridyl motif in ambient air under the irradiation of blue LEDs at room temperature has been developed. The reaction was facile and scalable, and proceeded with good functional group tolerance, affording pharmaceutically useful 2-acyl pyridines. The electron paramagnetic resonance (EPR) studies together with control experiments showed that the singlet oxygen (1O2) and superoxide anion (O2˙?) are the reactive oxidants. The1O2generation mechanism correlated well with the photophysical properties of the substrate (Z)-triaryl-substituted alkenes, the excited state of which was proved to serve as the triplet sensitizer for the generation of1O2
- Chen, Hua,Fu, Haiyan,Ge, Yicen,Li, Ruixiang,Li, Shun,Li, Wenjing,Luo, Lihua,Xu, Jiaqi,Yuan, Maolin,Zheng, Xueli
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supporting information
p. 3649 - 3655
(2021/06/06)
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- Pd-Catalysed carbonylative Suzuki-Miyaura cross-couplings using Fe(CO)5under mild conditions: generation of a highly active, recyclable and scalable ‘Pd-Fe’ nanocatalyst
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The dual function and role of iron(0) pentacarbonyl [Fe(CO)5] has been identified in gaseous CO-free carbonylative Suzuki-Miyaura cross-couplings, in which Fe(CO)5supplied COin situ, leading to the propagation of catalytically active Pd-Fe nanoparticles. Compared with typical carbonylative reaction conditions, CO gas (at high pressures), specialised exogenous ligands and inert reaction conditions were avoided. Our developed reaction conditions are mild, do not require specialised CO high pressure equipment, and exhibit wide functional group tolerance, giving a library of biaryl ketones in good yields.
- Zhu, Zhuangli,Wang, Zhenhua,Jian, Yajun,Sun, Huaming,Zhang, Guofang,Lynam, Jason M.,McElroy, C. Robert,Burden, Thomas J.,Inight, Rebecca L.,Fairlamb, Ian J. S.,Zhang, Weiqiang,Gao, Ziwei
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supporting information
p. 920 - 926
(2021/02/09)
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- Iodination/Amidation of the N-Alkyl (Iso)quinolinium Salts
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The NaIO4-mediated sequential iodination/amidation reaction of N-alkyl quinolinium iodide salts has been first developed. This cascade process provides an efficient way to rapidly synthesize 3-iodo-N-alkyl quinolinones with high regioselectivity and good functional group tolerance. This protocol was also amenable to the isoquinolinium salts, thus providing a complementary method for preparing the 4-iodo-N-alkyl isoquinolinones.
- Tang, Juan,Chen, Xue,Zhao, Chao-Qun,Li, Wen-Jing,Li, Shun,Zheng, Xue-Li,Yuan, Mao-Lin,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua
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supporting information
p. 716 - 730
(2020/12/22)
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- Visible-Light-Promoted Regio- and Stereoselective Oxyalkenyl-ation of Phosphinyl Allenes
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A highly regio- and stereoselective oxyalkenylation of phosphinyl allenes is revealed for the first time. This protocol, merging visible light photoredox and palladium catalysis, provides a direct approach to conjugated tertiary allylic alcohol derivatives with broad functional group tolerance in moderate to excellent yields. Mechanistic studies suggest that, although two possible pathways exist in the transformation, radical oxyalkenylation promoted by visible light photoredox takes over the major pathway. (Figure presented.).
- Sun, Xue,Liu, Teng,Yang, Yan-Tong,Gu, Yue-Jie,Liu, Yu-Wei,Ji, Yi-Gang,Luo, Kai,Zhu, Jie,Wu, Lei
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supporting information
p. 2701 - 2708
(2020/05/18)
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- Photodelivery of β-phenylethylamines
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We have developed the first photodonors for the trace amino neurotransmitters, β-phenylethylamine (DPSY1) and β-methylphenylethylamine (DPSY2). Our photodonors react rapidly with photosensitized singlet dioxygen (1O2) to yield the amines. The photodeliver
- Lee, Sumin,Yi, Seung Yeon,You, Youngmin
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supporting information
p. 7842 - 7847
(2020/11/02)
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- Palladium-Catalyzed Regioselective Acylation of Diazines with Toluenes: A New Approach to the Synthesis of ortho-Diacylbenzenes
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A highly efficient and practical procedure for chemo- and regioselective synthesis of ortho-diacylbenzenes through Pd-catalyzed oxidative C–H bond activation has been developed. Using this method, a variety of ortho-diacylbenzenes were prepared in moderate to good yields, by direct acylation of diazines with toluene derivatives as acylation source. Ortho-diacylbenzenes may be used as precursors in synthesis of pharmaceuticals and agrochemicals.
- Afaridoun, Hadi,Kianmehr, Ebrahim,Seifinoferest, Behnoush
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- Acyl radicals from α-keto acids using a carbonyl photocatalyst: Photoredox-catalyzed synthesis of ketones
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Acyl radicals have been generated from α-keto acids using inexpensive and commercially available 2-chloro-thioxanthen-9-one as the photoredox catalyst under visible light illumination. These reactive species added to olefins or coupled with aryl halides via a bipyridylstabilized Ni(II) catalyst, enabling easy access to a diverse range of ketones. This reliable, atom-economical, and eco-friendly protocol is compatible with a wide range of functional groups.
- Zhu, Da-Liang,Wu, Qi,Young, David James,Wang, Hao,Ren, Zhi-Gang,Li, Hong-Xi
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supporting information
p. 6832 - 6837
(2020/10/12)
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- Directed ortho-Metalation of Arenesulfonyl Fluorides and Aryl Fluorosulfates
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Studies on directed ortho -metalation (DoM) of arenesulfonyl fluorides (ArSO 2 F) with in situ electrophile trapping are presented. Under optimized conditions (LDA, THF, -78 °C), a series of model substrates was mono- and difunctionalized with trimethylsilyl chloride in good yields. The synthetic results reveal powerful directing character of the SO 2 F group, being ahead of bromine and methoxy substituents. Under the same metalation conditions, aryl fluorosulfates (ArOSO 2 F) display fragmentation to arynes and migration of the SO 2 F group to the ortho position (anionic thia-Fries rearrangement).
- Talko, Alicja,Antoniak, Damian,Barbasiewicz, Micha?
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p. 2278 - 2286
(2019/05/24)
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- Facile photochemical synthesis of α-ketoamides and quinoxalines from amines and benzoylacetonitrile under mild conditions
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A selective protocol for the synthesis of either α-ketoamides or quinoxaline derivatives under the same reaction conditions has been achieved simply by varying substitution number of amino-groups. The method features metal-free, room temperature and broad substrate scopes as well as no extra oxidant. This process applies to various substituent groups and gives products in moderate to good yield. Finally, a rational mechanism was proposed.
- Zhou, Chao,Diao, Pinhui,Li, Xiaoji,Ge, Yanqin,Guo, Cheng
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supporting information
p. 371 - 374
(2018/06/27)
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- Synthesis and photodynamic effects of new porphyrin/4-oxoquinoline derivatives in the inactivation of S. aureus
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New porphyrin/4-oxoquinoline conjugates were synthesized from the Heck coupling reaction of a β-brominated porphyrin with 1-allyl-4-oxoquinoline derivatives, followed by demetallation and deprotection affording the promising photosensitizers 9a-e. Singlet oxygen studies have demonstrated that all the porphyrin/4-oxoquinoline conjugates 9a-e were capable of producing cytotoxic species and found to be excellent photosensitizing agents in the inactivation of S. aureus by the antimicrobial photodynamic therapy (aPDT) protocol.
- Sagrillo, Fernanda Savacini,Dias, Cristina,Gomes, Ana T.P.C.,Faustino, Maria A.F.,Almeida, Adelaide,Gon?alves De Souza, Alan,Costa, Amanda Rodrigues Pinto,Boechat, Fernanda Da Costa Santos,Bastos Vieira De Souza, Maria Cecília,Neves, Maria G.P.M.S.,Cavaleiro, José A.S.
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p. 1910 - 1922
(2019/08/20)
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- Cobalt-Catalyzed Oxygenation/Dearomatization of Furans
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The dearomatization of aromatic compounds using cobalt(II) acetylacetonate with triplet oxygen and triethylsilane converts furans, benzofurans, pyrroles, and thiophenes to a variety of products, including lactones, silyl peroxides, and ketones.
- Oswald, Jonathan P.,Woerpel
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p. 9067 - 9075
(2018/05/29)
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- Visible Light Promotes Decyanation Esterification Reaction of β - Ketonitriles with Dioxygen and Alcohols to α-Ketoesters
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A green and mild method has been developed for the conversion of β-ketonitriles into α-ketoesters under catalyst-free conditions. A plausible mechanism is that visible light promotes singlet oxygen generation to form the products through oxidative C-H bond functionalization and C-C σ -bond cleavage.
- Xu, Chen,Zhang, Nan-Nan,Li, Xiao-Ji,Ge, Yan-Qin,Diao, Pin-Hui,Guo, Cheng
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p. 1065 - 1070
(2018/05/01)
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- Carbazole-triazine based donor-acceptor porous organic frameworks for efficient visible-light photocatalytic aerobic oxidation reactions
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We report the synthesis of a series of carbazole-triazine based donor-acceptor (D-A) POFs and their photocatalytic activities for aerobic oxidation reactions. The simultaneous introduction of a carbazole-based electron donor and a triazine-based electron acceptor in D-A POFs stabilizes the charge transfer state and enables an efficient triplet-triplet energy transfer to generate 1O2. Meanwhile, systematic variation of the D-A distance results in the tunable photoredox properties and consequently the efficiency for generation of reactive oxygen species (ROSs). Upon visible light excitation, all three D-A POFs exhibit excellent capability to promote three aerobic oxidations: sulfide oxidation, oxidative amine coupling, and Mannich reactions. This systematic study validates the design principle of D-A POFs as high-performance photo-oxidation catalysts with wide substrate scope and excellent stability and recyclability.
- Luo, Jian,Lu, Jingzhi,Zhang, Jian
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supporting information
p. 15154 - 15161
(2018/08/17)
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- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
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A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
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p. 3275 - 3284
(2018/03/25)
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- Singlet oxygen generation from poly[4-diacetoxyiodo]styrene and hydrogen peroxide
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Treatment of hydrogen peroxide with a polymer-supported hypervalent iodine compound, poly[4-diacetoxyiodo] styrene (PDAIS), generates singlet molecular oxygen (1O2). Singlet oxygen generation was proved by trapping with typical organic compounds such as conjugated dienes, aromatic dienes, and electron-rich alkene. When compared to monomer analogue, the use of PDAIS in peroxidation of substrates gave slightly better yields (45%–96%). Regeneration and reuse of PDAIS showed similar activity. The mechanism underlying generation of singlet oxygen and reaction scope was examined.
- ?atir, Mustafa
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p. 467 - 475
(2017/09/15)
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- Bifunctional photocatalysts for enantioselective aerobic oxidation of β-ketoesters
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A novel visible-light-responsive chiral ligand has been developed by grafting a triplet state photosensitizer to chiral bisoxazoline ligands. Complexation of this ligand with Ni(acac)2 results in a powerful catalyst for the asymmetric oxidation reaction of β-ketoesters, which uses oxygen or air as the green oxidant and visible light or sunlight as the ideal driving force. Using this protocol, Products containing the α-hydroxy-β-dicarbonyl motif are produced in high yields and with excellent enantiopurities.
- Ding, Wei,Lu, Liang-Qiu,Zhou, Quan-Quan,Wei, Yi,Chen, Jia-Rong,Xiao, Wen-Jing
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supporting information
p. 63 - 66
(2017/05/16)
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- Visible light-driven photogeneration of hydrogen sulfide
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The combined use of a singlet oxygen photosensitizer and 1,3-diarylisobenzothiophene enables efficient generation of hydrogen sulfide under visible light illumination.
- Yi, Seung Yeon,Moon, Yu Kyung,Kim, Sinheui,Kim, Sonam,Park, Gyurim,Kim, Jin Ju,You, Youngmin
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supporting information
p. 11830 - 11833
(2017/11/03)
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- Pd(II)-Catalyzed Direct ortho-C-H Acylation of Aromatic Ketones by Oxidative Decarboxylation of α-Oxocarboxylic Acids
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A Pd-catalyzed decarboxylative acylation of aromatic ketones with α-oxocarboxylic acids was developed, and 1,2-diacylbenzenes were formed in up to 90% yield with excellent ortho-selectivity. This work demonstrates the first successful attempt to direct C-H acylation of aromatic ketones without the need for prederivatization to imines. The acylation reaction was inhibited by radical scavengers such as TEMPO, and 2,2,6,6-tetramethylpiperidin-1-yl benzoate, the adduct of TEMPO and a benzoyl radical, has been isolated and characterized. This finding is compatible with the intermediacy of acyl radicals. A mechanism involving the reaction of the palladacyclic complexes of aryl ketones with acyl radicals is proposed.
- Lee, Pui-Yiu,Liang, Peiwen,Yu, Wing-Yiu
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p. 2082 - 2085
(2017/04/28)
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