The Experts below are selected from a list of 744 Experts worldwide ranked by ideXlab platform
Hiroshi Nishihara - One of the best experts on this subject based on the ideXlab platform.
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platinadithiolene conjugated Pyrylium Salt with strong intramolecular donor acceptor interaction
Chemical Communications, 2011Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Yuki Yamamoto, Shoko Kume, Masayuki Nihei, Hiroki Oshio, Hiroshi NishiharaAbstract:Protonation of a new platinum complex, Pt(1-pdtAq)(tBu2bpy), where 1-pdtAq is 1-(phenyldithiolenethynyl)anthraquinone, afforded a cyclized structure, [Pt(1-pdtPyl)(tBu2bpy)]+, with a unique electronic structure due to intense intramolecular charge transfer.
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Platinadithiolene-conjugated Pyrylium Salt with strong intramolecular donor–acceptor interaction
Chemical communications (Cambridge England), 2010Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Yuki Yamamoto, Shoko Kume, Masayuki Nihei, Hiroki Oshio, Hiroshi NishiharaAbstract:Protonation of a new platinum complex, Pt(1-pdtAq)(tBu2bpy), where 1-pdtAq is 1-(phenyldithiolenethynyl)anthraquinone, afforded a cyclized structure, [Pt(1-pdtPyl)(tBu2bpy)]+, with a unique electronic structure due to intense intramolecular charge transfer.
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Double protonation of 1,5-bis(triarylaminoethynyl)anthraquinone to form a paramagnetic pentacyclic diPyrylium Salt.
Journal of the American Chemical Society, 2010Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Shoko Kume, Fumiyuki Toshimitsu, Kiyotaka Inayoshi, Hiroshi NishiharaAbstract:Protonation-induced intramolecular cyclization reactions of new donor (D)−acceptor (A) and D−A−D conjugated molecules 1-triarylaminoethynylanthraquinone (1-AmAq) and 1,5-bis(triarylaminoethynyl)anthraquinone (1,5-Am2Aq), respectively, were achieved. The former undergoes monoprotonation with bis(trifluoromethanesulfone)imide acid (TFSIH) to give Pyrylium Salt [1-AmPyl]TFSI, whereas the latter undergoes a novel double proton cyclization reaction to yield 1,5-bis(triarylamino)diPyrylium Salt [1,5-Am2Pyl2](TFSI)2 with a new pentacyclic backbone. This divalent cationic Salt can be reduced to give the neutral species 2,8-bis(triarylamino)benzo[de]isochromeno[1,8-gh]chromene ([1,5-Am2Pyl2]0), which maintains the planar pentacyclic backbone. The obtained condensed-ring compounds show unique optical, electrochemical, and magnetic properties due to the extremely narrow HOMO−LUMO gap. In particular, the dication [1,5-Am2Pyl2]2+ shows paramagnetic behavior with two spins centered on two triarylamine moieties through ...
A. Criqui - One of the best experts on this subject based on the ideXlab platform.
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mechanistic approach to a photochemical thermal dual cure initiating system based on Pyrylium Salt hydroperoxide for epoxide cationic polymerization
Polymer Chemistry, 2017Co-Authors: M. Lecompère, Xavier Allonas, D. Maréchal, A. CriquiAbstract:Dual-cure initiating systems have emerged as promising alternatives to perform fast and on-demand curing of thick polymers. In this paper, a system based on Pyrylium Salt/hydroperoxide is reported to be efficient in the polymerization of epoxide resins. The chemical mechanisms involved are studied by ESR, laser flash photolysis and fluorimetry. It is found that the interaction between Pyrylium Salts and hydroperoxide releases a proton that could initiate the polymerization reaction at room temperature as well as under UV light. The combination of both methods allows the polymerization of a thick sample by photoinduced thermal polymerization.
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Mechanistic approach to a photochemical/thermal dual-cure initiating system based on Pyrylium Salt–hydroperoxide for epoxide cationic polymerization
Polymer Chemistry, 2017Co-Authors: M. Lecompère, Xavier Allonas, D. Maréchal, A. CriquiAbstract:Dual-cure initiating systems have emerged as promising alternatives to perform fast and on-demand curing of thick polymers. In this paper, a system based on Pyrylium Salt/hydroperoxide is reported to be efficient in the polymerization of epoxide resins. The chemical mechanisms involved are studied by ESR, laser flash photolysis and fluorimetry. It is found that the interaction between Pyrylium Salts and hydroperoxide releases a proton that could initiate the polymerization reaction at room temperature as well as under UV light. The combination of both methods allows the polymerization of a thick sample by photoinduced thermal polymerization.
Miguel A Miranda - One of the best experts on this subject based on the ideXlab platform.
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Experimental and theoretical studies on the radical-cation-mediated imino-Diels-Alder reaction.
Organic letters, 2011Co-Authors: Raúl Pérez-ruiz, Luis R. Domingo, M. Consuelo Jiménez, Miguel A MirandaAbstract:The feasibility of an electron transfer imino-Diels–Alder reaction between N-benzylideneaniline and arylalkenes in the presence of a Pyrylium Salt as a photosensitizer has been demonstrated by a combination of product studies, laser flash photolysis (LFP), and DFT theoretical calculations. A stepwise mechanism involving two intermediates and two transition states is proposed.
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Abatement of the major contaminants present in olive oil industry wastewaters by different oxidation methods: ozone and/or UV radiation versus solar light.
Water science and technology : a journal of the International Association on Water Pollution Research, 2001Co-Authors: Miguel A Miranda, Ana M. Amat, Antonio ArquesAbstract:Four different cinnamic acids (caffeic acid, ferulic acid, p-coumaric acid and cinnamic acid) present in olive oil wastewaters, were treated with advanced oxidation methods: ozone and/or UV radiation. Basic and acid media were tested. Differences between all four acids were found, both in the reaction times and the intermediates formed. Based on a careful study of these intermediates and the variation of their concentrations all along the reaction time, a general mechanism for the degradative oxidation of cinnamic acids is proposed. These results are compared with those obtained with solar light, using a Pyrylium Salt as a catalyst.
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Pyrylium Salt photosensitised degradation of phenolic contaminants present in olive oil wastewaters with solar light
Applied Catalysis B-environmental, 2001Co-Authors: Miguel A Miranda, Francisco Galindo, A M Amat, A ArquesAbstract:Abstract Solar light photodegradation, catalysed by a Pyrylium Salt, of seven benzoic acids present in olive oil mill, has been studied. Significant percentages of photodegradation (20–40%) have been achieved after 6 h of solar exposure for six of the acids, even though they were expected to be difficult to oxidise, due to the presence of an electron-withdrawing carboxylic acid group directly attached to the aromatic ring. Quenching constants for the electron-transfer process between the substrate and the excited catalyst were calculated by means of fluorescence measurements for syringic acid (66×10 9 M −1 s −1 ), gallic acid (51×10 9 M −1 s −1 ), veratric acid (51×10 9 M −1 s −1 ), vanillic acid (48×10 9 M −1 s −1 ), protocatechuic acid (37×10 9 M −1 s −1 ) and p -hydroxybenzoic acid (15×10 9 M −1 s −1 ); no quenching was found for benzoic acid. These photophysical measurements are in good correlation with the yields obtained in the Pyrylium Salt photocatalysed degradation of those phenolic acids.
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Pyrylium Salt photosensitized degradation of phenolic contaminants derived from cinnamic acid with solar light
Applied Catalysis B-environmental, 2000Co-Authors: Miguel A Miranda, Francisco Galindo, A M Amat, A ArquesAbstract:Abstract Solar light photodegradation of three cinnamic acid derivatives (ferulic acid, caffeic acid and p -coumaric acid) present in olive oil industry wastewater has been achieved using 2,4,6-triphenylPyrylium hydrogen sulfate as an electron transfer photosensitiser. The parent cinnamic acid undergoes no photodegradation under the employed reaction conditions. The relative reactivities are in agreement with expectations based on qualitative reasoning: the substrates with two electron-donating groups, ferulic and caffeic acid, react faster than p -coumaric acid, which has only one activating substituent; while the non-activated cinnamic acid is nearly unreactive. The data obtained from fluorescence measurements show that the excited singlet state of the Pyrylium Salt is quenched by the acids, with the following rate constants: 3.6×10 9 M −1 s −1 for cinnamic acid, 4.4×10 10 M −1 s −1 in the case of p -coumaric acid, 8.7×10 10 M −1 s −1 for caffeic acid, and 1.0×10 11 M −1 s −1 for ferulic acid. These values are in good agreement with the order of reactivities observed in the preparative solar reactions.
Koya Prabhakara Rao - One of the best experts on this subject based on the ideXlab platform.
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platinadithiolene conjugated Pyrylium Salt with strong intramolecular donor acceptor interaction
Chemical Communications, 2011Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Yuki Yamamoto, Shoko Kume, Masayuki Nihei, Hiroki Oshio, Hiroshi NishiharaAbstract:Protonation of a new platinum complex, Pt(1-pdtAq)(tBu2bpy), where 1-pdtAq is 1-(phenyldithiolenethynyl)anthraquinone, afforded a cyclized structure, [Pt(1-pdtPyl)(tBu2bpy)]+, with a unique electronic structure due to intense intramolecular charge transfer.
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Platinadithiolene-conjugated Pyrylium Salt with strong intramolecular donor–acceptor interaction
Chemical communications (Cambridge England), 2010Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Yuki Yamamoto, Shoko Kume, Masayuki Nihei, Hiroki Oshio, Hiroshi NishiharaAbstract:Protonation of a new platinum complex, Pt(1-pdtAq)(tBu2bpy), where 1-pdtAq is 1-(phenyldithiolenethynyl)anthraquinone, afforded a cyclized structure, [Pt(1-pdtPyl)(tBu2bpy)]+, with a unique electronic structure due to intense intramolecular charge transfer.
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Double protonation of 1,5-bis(triarylaminoethynyl)anthraquinone to form a paramagnetic pentacyclic diPyrylium Salt.
Journal of the American Chemical Society, 2010Co-Authors: Koya Prabhakara Rao, Tetsuro Kusamoto, Ryota Sakamoto, Shoko Kume, Fumiyuki Toshimitsu, Kiyotaka Inayoshi, Hiroshi NishiharaAbstract:Protonation-induced intramolecular cyclization reactions of new donor (D)−acceptor (A) and D−A−D conjugated molecules 1-triarylaminoethynylanthraquinone (1-AmAq) and 1,5-bis(triarylaminoethynyl)anthraquinone (1,5-Am2Aq), respectively, were achieved. The former undergoes monoprotonation with bis(trifluoromethanesulfone)imide acid (TFSIH) to give Pyrylium Salt [1-AmPyl]TFSI, whereas the latter undergoes a novel double proton cyclization reaction to yield 1,5-bis(triarylamino)diPyrylium Salt [1,5-Am2Pyl2](TFSI)2 with a new pentacyclic backbone. This divalent cationic Salt can be reduced to give the neutral species 2,8-bis(triarylamino)benzo[de]isochromeno[1,8-gh]chromene ([1,5-Am2Pyl2]0), which maintains the planar pentacyclic backbone. The obtained condensed-ring compounds show unique optical, electrochemical, and magnetic properties due to the extremely narrow HOMO−LUMO gap. In particular, the dication [1,5-Am2Pyl2]2+ shows paramagnetic behavior with two spins centered on two triarylamine moieties through ...
A Arques - One of the best experts on this subject based on the ideXlab platform.
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Pyrylium Salt photosensitised degradation of phenolic contaminants present in olive oil wastewaters with solar light
Applied Catalysis B-environmental, 2001Co-Authors: Miguel A Miranda, Francisco Galindo, A M Amat, A ArquesAbstract:Abstract Solar light photodegradation, catalysed by a Pyrylium Salt, of seven benzoic acids present in olive oil mill, has been studied. Significant percentages of photodegradation (20–40%) have been achieved after 6 h of solar exposure for six of the acids, even though they were expected to be difficult to oxidise, due to the presence of an electron-withdrawing carboxylic acid group directly attached to the aromatic ring. Quenching constants for the electron-transfer process between the substrate and the excited catalyst were calculated by means of fluorescence measurements for syringic acid (66×10 9 M −1 s −1 ), gallic acid (51×10 9 M −1 s −1 ), veratric acid (51×10 9 M −1 s −1 ), vanillic acid (48×10 9 M −1 s −1 ), protocatechuic acid (37×10 9 M −1 s −1 ) and p -hydroxybenzoic acid (15×10 9 M −1 s −1 ); no quenching was found for benzoic acid. These photophysical measurements are in good correlation with the yields obtained in the Pyrylium Salt photocatalysed degradation of those phenolic acids.
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Pyrylium Salt photosensitized degradation of phenolic contaminants derived from cinnamic acid with solar light
Applied Catalysis B-environmental, 2000Co-Authors: Miguel A Miranda, Francisco Galindo, A M Amat, A ArquesAbstract:Abstract Solar light photodegradation of three cinnamic acid derivatives (ferulic acid, caffeic acid and p -coumaric acid) present in olive oil industry wastewater has been achieved using 2,4,6-triphenylPyrylium hydrogen sulfate as an electron transfer photosensitiser. The parent cinnamic acid undergoes no photodegradation under the employed reaction conditions. The relative reactivities are in agreement with expectations based on qualitative reasoning: the substrates with two electron-donating groups, ferulic and caffeic acid, react faster than p -coumaric acid, which has only one activating substituent; while the non-activated cinnamic acid is nearly unreactive. The data obtained from fluorescence measurements show that the excited singlet state of the Pyrylium Salt is quenched by the acids, with the following rate constants: 3.6×10 9 M −1 s −1 for cinnamic acid, 4.4×10 10 M −1 s −1 in the case of p -coumaric acid, 8.7×10 10 M −1 s −1 for caffeic acid, and 1.0×10 11 M −1 s −1 for ferulic acid. These values are in good agreement with the order of reactivities observed in the preparative solar reactions.
