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Masahiko Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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Reversible Formation of Self-Assembly Gels Containing Giant Vesicles in Trifluoromethylbenzene Using Oxymethylenehelicene Oligomers with Terminal C16 Alkyl Groups
Bulletin of the Chemical Society of Japan, 2020Co-Authors: Tsukasa Sawato, Mieko Arisawa, Masahiko YamaguchiAbstract:A 1:1 mixture of pseudoenantiomeric oxymethylenehelicene (P)-pentamer and (M)-hexamer with terminal C16 alkyl groups in Trifluoromethylbenzene formed hetero-double-helices and their self-assembly g...
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Fibril Film Formation of Pseudoenantiomeric Oxymethylenehelicene Oligomers at the Liquid–Solid Interface: Structural Changes, Aggregation, and Discontinuous Heterogeneous Nucleation
Chemistry (Weinheim an der Bergstrasse Germany), 2015Co-Authors: Masanori Shigeno, Tsukasa Sawato, Masahiko YamaguchiAbstract:Oxymethylenehelicene (P)- and (M)-oligomers up to a nonamer were synthesized by a building block method. The oligomers formed dimeric homoaggregates in Trifluoromethylbenzene. A mixture of the pseudoenantiomeric (P)-pentamer and (M)-hexamer formed a heteroaggregate, which self-assembled into one-dimensional fibril films at the liquid-solid interface. Discontinuous heterogeneous nucleation occurred, which involved the formation of particles that were 50 nm in diameter and subsequent fibril growth from these particles. The fibril film was formed on the solid surface and the molecules remained dissociated in solution. The fibril film formation was affected by seeding and the solid surface materials.
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Material Clocking by Silica Nanoparticle Precipitation in Solution Phase that is Tunable by Organic Molecules.
ChemPlusChem, 2015Co-Authors: Masamichi Miyagawa, Masahiko YamaguchiAbstract:Material clocking is an important biological phenomenon through which the structure of a material changes sharply with time after activation. A suspension of silica (P)-nanoparticles in the presence of organic molecules in solution exhibits such a material clocking phenomenon during delayed precipitation with high accuracy and precision. A mixture of ethynylhelicene (P)-pentamer and silica (P)-nanoparticles with an average diameter of 70 nm grafted with (P)-helicene in Trifluoromethylbenzene is sonicated for activation and dispersion. The (P)-nanoparticles start to precipitate after 3 h of settling at 25 °C and precipitate completely after 4 h. UV/Vis, CD, and DLS analyses of the process show no change during the initial 3 h, but then an abrupt stair-shaped kinetic change occurs with concomitant precipitation and removal of the (P)-pentamer from the solution phase. The delay in the precipitation can be tuned by the structure of molecules added to the (P)-nanoparticle suspension.
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Equilibrium shift in solution: molecular shape recognition and precipitation of a synthetic double helix using helicene-grafted silica nanoparticles.
Chemistry (Weinheim an der Bergstrasse Germany), 2013Co-Authors: Masamichi Miyagawa, Wataru Ichinose, Masahiko YamaguchiAbstract:Chiral silica nanoparticles (70 nm) grafted with (P)-helicene recognized the molecular shape of double helix and random coil (P)-ethynylhelicene oligomers in solution. A mixture of the (P)-nanoparticles and double helix precipitated much faster than a mixture of the (P)-nanoparticles and random coil, and the precipitate contained only the double helix. The mixture of the (P)-nanoparticles and (P)-ethynylhelicene pentamer reversibly dispersed in Trifluoromethylbenzene upon heating at 70 °C and precipitated upon cooling at 25 °C. When a 10:90 equilibrium mixture of the double helix and random coil in solution was treated with the (P)-nanoparticles, the double helix was precipitated in 53 % yield and was accompanied by equilibrium shift.
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Heteroaggregation between isomeric amido-ethynyl-amidohelicene tridomain oligomers.
The Journal of organic chemistry, 2012Co-Authors: Wataru Ichinose, Jun Ito, Masahiko YamaguchiAbstract:Three isomers, i.e., P4M5P4-1, M4P5M4-1, and M4M5M4-1, of amido-ethynyl-amidohelicene tridomain oligomers were synthesized. P4M5P4-1 formed four homoaggregate states, i.e., all-dimer, amido-dimer, ethynyl-dimer, and random-coil states, by independent aggregation and disaggregation at the ethynyl and amido domains. Then, possible combinations of heteroaggregation were examined between the isomeric tridomain oligomers P4P5P4-1, P4M5P4-1, M4P5M4-1, and M4M5M4-1. When P4P5P4-1 and P4M5P4-1 were mixed in THF, to which Trifluoromethylbenzene was added, heteroaggregates with an all-dimer structure were formed without forming homoaggregates. The heteroaggregation initially occurred at the central ethynyl domain, which was followed by the aggregation at the amido domains. Heteroaggregates were also formed using the combinations P4P5P4-1/M4M5M4-1 and P4M5P4-1/M4P5M4-1, and the results indicated an important role for the central ethynyl domain for heteroaggregation.
Henri Doucet - One of the best experts on this subject based on the ideXlab platform.
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Regiodivergent Late‐Stage Pd‐ or Ru‐Catalyzed C–H Bond Functionalization Applied to the Straightforward Synthesis of N‐Methylated Diflufenican Derivatives
European Journal of Organic Chemistry, 2020Co-Authors: Mohamed Elhadi Benhalouche, Abdellah Miloudi, Amal Benzai, Marie-pierre Cordier, Jean-françois Soulé, Henri DoucetAbstract:The late-stage C-H diversification methodology was applied to the preparation of arylated Diflufenican derivatives. Using a palladium catalyst associated with potassium pivalate, a regioselective arylation of the C-H bond flanked by the two fluorine atoms was observed. The reaction tolerated a wide range of useful functional groups on the aryl bromide. Conversely, the use of a ruthenium catalyst allowed to arylate the Trifluoromethylbenzene ring of Diflufenican. To the best of our knowledge, these synthetic schemes are the first ones allowing the preparation of such arylated Diflufenican derivatives.
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Regiodivergent Late-Stage Pd- or Ru-Catalyzed C-H Bond Functionalization Applied to the Straightforward Synthesis ofN-Methylated Diflufenican Derivatives
European Journal of Organic Chemistry, 2020Co-Authors: Mohamed Elhadi Benhalouche, Abdellah Miloudi, Amal Benzai, Jean-françois Soulé, Marie Cordier, Henri DoucetAbstract:The late-stage C-H diversification methodology was applied to the preparation of arylated Diflufenican derivatives. Using a palladium catalyst associated with potassium pivalate, a regioselective arylation of the C-H bond flanked by the two fluorine atoms was observed. The reaction tolerated a wide range of useful functional groups on the aryl bromide. Conversely, the use of a ruthenium catalyst allowed to arylate the Trifluoromethylbenzene ring of Diflufenican. To the best of our knowledge, these synthetic schemes are the first ones allowing the preparation of such arylated Diflufenican derivatives.
Mohamed Elhadi Benhalouche - One of the best experts on this subject based on the ideXlab platform.
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Regiodivergent Late‐Stage Pd‐ or Ru‐Catalyzed C–H Bond Functionalization Applied to the Straightforward Synthesis of N‐Methylated Diflufenican Derivatives
European Journal of Organic Chemistry, 2020Co-Authors: Mohamed Elhadi Benhalouche, Abdellah Miloudi, Amal Benzai, Marie-pierre Cordier, Jean-françois Soulé, Henri DoucetAbstract:The late-stage C-H diversification methodology was applied to the preparation of arylated Diflufenican derivatives. Using a palladium catalyst associated with potassium pivalate, a regioselective arylation of the C-H bond flanked by the two fluorine atoms was observed. The reaction tolerated a wide range of useful functional groups on the aryl bromide. Conversely, the use of a ruthenium catalyst allowed to arylate the Trifluoromethylbenzene ring of Diflufenican. To the best of our knowledge, these synthetic schemes are the first ones allowing the preparation of such arylated Diflufenican derivatives.
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Regiodivergent Late-Stage Pd- or Ru-Catalyzed C-H Bond Functionalization Applied to the Straightforward Synthesis ofN-Methylated Diflufenican Derivatives
European Journal of Organic Chemistry, 2020Co-Authors: Mohamed Elhadi Benhalouche, Abdellah Miloudi, Amal Benzai, Jean-françois Soulé, Marie Cordier, Henri DoucetAbstract:The late-stage C-H diversification methodology was applied to the preparation of arylated Diflufenican derivatives. Using a palladium catalyst associated with potassium pivalate, a regioselective arylation of the C-H bond flanked by the two fluorine atoms was observed. The reaction tolerated a wide range of useful functional groups on the aryl bromide. Conversely, the use of a ruthenium catalyst allowed to arylate the Trifluoromethylbenzene ring of Diflufenican. To the best of our knowledge, these synthetic schemes are the first ones allowing the preparation of such arylated Diflufenican derivatives.
Wataru Ichinose - One of the best experts on this subject based on the ideXlab platform.
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Equilibrium shift in solution: molecular shape recognition and precipitation of a synthetic double helix using helicene-grafted silica nanoparticles.
Chemistry (Weinheim an der Bergstrasse Germany), 2013Co-Authors: Masamichi Miyagawa, Wataru Ichinose, Masahiko YamaguchiAbstract:Chiral silica nanoparticles (70 nm) grafted with (P)-helicene recognized the molecular shape of double helix and random coil (P)-ethynylhelicene oligomers in solution. A mixture of the (P)-nanoparticles and double helix precipitated much faster than a mixture of the (P)-nanoparticles and random coil, and the precipitate contained only the double helix. The mixture of the (P)-nanoparticles and (P)-ethynylhelicene pentamer reversibly dispersed in Trifluoromethylbenzene upon heating at 70 °C and precipitated upon cooling at 25 °C. When a 10:90 equilibrium mixture of the double helix and random coil in solution was treated with the (P)-nanoparticles, the double helix was precipitated in 53 % yield and was accompanied by equilibrium shift.
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Heteroaggregation between isomeric amido-ethynyl-amidohelicene tridomain oligomers.
The Journal of organic chemistry, 2012Co-Authors: Wataru Ichinose, Jun Ito, Masahiko YamaguchiAbstract:Three isomers, i.e., P4M5P4-1, M4P5M4-1, and M4M5M4-1, of amido-ethynyl-amidohelicene tridomain oligomers were synthesized. P4M5P4-1 formed four homoaggregate states, i.e., all-dimer, amido-dimer, ethynyl-dimer, and random-coil states, by independent aggregation and disaggregation at the ethynyl and amido domains. Then, possible combinations of heteroaggregation were examined between the isomeric tridomain oligomers P4P5P4-1, P4M5P4-1, M4P5M4-1, and M4M5M4-1. When P4P5P4-1 and P4M5P4-1 were mixed in THF, to which Trifluoromethylbenzene was added, heteroaggregates with an all-dimer structure were formed without forming homoaggregates. The heteroaggregation initially occurred at the central ethynyl domain, which was followed by the aggregation at the amido domains. Heteroaggregates were also formed using the combinations P4P5P4-1/M4M5M4-1 and P4M5P4-1/M4P5M4-1, and the results indicated an important role for the central ethynyl domain for heteroaggregation.
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Heteroaggregation between Isomeric Amido-ethynyl-amidohelicene Tridomain Oligomers
2012Co-Authors: Wataru Ichinose, Jun Ito, Masahiko YamaguchiAbstract:Three isomers, i.e., P4M5P4-1, M4P5M4-1, and M4M5M4-1, of amido-ethynyl-amidohelicene tridomain oligomers were synthesized. P4M5P4-1 formed four homoaggregate states, i.e., all-dimer, amido-dimer, ethynyl-dimer, and random-coil states, by independent aggregation and disaggregation at the ethynyl and amido domains. Then, possible combinations of heteroaggregation were examined between the isomeric tridomain oligomers P4P5P4-1, P4M5P4-1, M4P5M4-1, and M4M5M4-1. When P4P5P4-1 and P4M5P4-1 were mixed in THF, to which Trifluoromethylbenzene was added, heteroaggregates with an all-dimer structure were formed without forming homoaggregates. The heteroaggregation initially occurred at the central ethynyl domain, which was followed by the aggregation at the amido domains. Heteroaggregates were also formed using the combinations P4P5P4-1/M4M5M4-1 and P4M5P4-1/M4P5M4-1, and the results indicated an important role for the central ethynyl domain for heteroaggregation
Chuanjun Xia - One of the best experts on this subject based on the ideXlab platform.
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CCC–Pincer–NHC Osmium Complexes: New Types of Blue-Green Emissive Neutral Compounds for Organic Light-Emitting Devices (OLEDs)
Organometallics, 2014Co-Authors: Roberto G. Alabau, Beatriz Eguillor, Jim Esler, Miguel A. Esteruelas, Montserrat Oliván, Enrique Oñate, Jui-yi Tsai, Chuanjun XiaAbstract:Novel homoleptic and heteroleptic NHC carbene containing bis(tridentate) osmium(II) complexes have been designed, synthesized, and characterized, and their photophysical properties have been studied. The complex OsH6(PiPr3)2 (1) reacts with the tetrafluoroborate salts of 1,3-bis(3-methylbenzimidazolium-1-yl)benzene and 1,3-bis(3-methylimidazolium-1-yl)benzene, in dimethylformamide, under reflux to afford the hydride–carbonyl derivatives [OsH(CNHCCarylCbenzimidazolium)(CO)(PiPr3)2]BF4 (2) and [OsH(CNHCCarylCimidazolium)(CO)(PiPr3)2]BF4 (3), as a result of the direct metalation of one of the NHC units of the salts, the activation of the C–H bond at the 6-position of the bridged aryl group, and metal carbonylation by solvent decarbonylation. In contrast to the BF4 salts, under the same conditions, the iodide salts of 1,3-bis(3-methylbenzimidazolium-1-yl)benzene, 1,3-bis(3-methylimidazolium-1-yl)benzene, and 1,3-bis(3-methylbenzimidazolium-1-yl)-5-Trifluoromethylbenzene undergo direct metalation of both NHC u...
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CCC–Pincer–NHC Osmium Complexes: New Types of Blue-Green Emissive Neutral Compounds for Organic Light-Emitting Devices (OLEDs)
2014Co-Authors: Roberto G. Alabau, Beatriz Eguillor, Jim Esler, Miguel A. Esteruelas, Jui-yi Tsai, Montserrat Oliván, Enrique Oñate, Chuanjun XiaAbstract:Novel homoleptic and heteroleptic NHC carbene containing bis(tridentate) osmium(II) complexes have been designed, synthesized, and characterized, and their photophysical properties have been studied. The complex OsH6(PiPr3)2 (1) reacts with the tetrafluoroborate salts of 1,3-bis(3-methylbenzimidazolium-1-yl)benzene and 1,3-bis(3-methylimidazolium-1-yl)benzene, in dimethylformamide, under reflux to afford the hydride–carbonyl derivatives [OsH(CNHCCarylCbenzimidazolium)(CO)(PiPr3)2]BF4 (2) and [OsH(CNHCCarylCimidazolium)(CO)(PiPr3)2]BF4 (3), as a result of the direct metalation of one of the NHC units of the salts, the activation of the C–H bond at the 6-position of the bridged aryl group, and metal carbonylation by solvent decarbonylation. In contrast to the BF4 salts, under the same conditions, the iodide salts of 1,3-bis(3-methylbenzimidazolium-1-yl)benzene, 1,3-bis(3-methylimidazolium-1-yl)benzene, and 1,3-bis(3-methylbenzimidazolium-1-yl)-5-Trifluoromethylbenzene undergo direct metalation of both NHC units and C–H bond activation of the bridged aryl group at the 2-position to give the respective osmium(IV) dihydrides [OsH2(CNHCCarylCNHC)(PiPr3)2]I (4a–6a), which by deprotonation with KtBuO yield the osmium(II) monohydrides OsH(CNHCCarylCNHC)(PiPr3)2 (7–9). The reactions of 7 with 1,3-bis(3-methylbenzimidazolium-1-yl)benzene tetrafluoroborate and of 9 with 1,3-bis(3-methylbenzimidazolium-1-yl)-5-Trifluoromethylbenzene tetrafluoroborate lead to the homoleptic derivatives Os(CNHCCarylCNHC)2 (10, 11), whereas the reactions of 9 with the tetrafluoroborate salts of 1,3-bis(3-methylbenzimidazolium-1-yl)benzene and 1,3-bis(3-methylimidazolium-1-yl)benzene generate heteroleptic Os(CNHCCarylCNHC)(CNHCCaryl′CNHC) (12) and Os(CNHCCaryl′CNHC)(CNHC′CarylCNHC′) (13). Treatment of 7 with 3,5-bis(3-methylbenzimidazolium-1-yl)-2,6-dimethylpyridine tetrafluoroborate affords the salt [Os(CNHCCarylCNHC)(CNHCCaryl′CNHC)]BF4 (14), with Caryl′ being a pyridinium group. Its deprotonation generates the neutral heteroleptic derivative Os(CNHCCarylCNHC)(CNHCCaryl′CNHC) (15). Complexes 10–13 and 15 are emissive in the blue-green spectral region with high quantum yields in the solid state, which reach 0.62 for 11. OLEDs using this compound as an emitting material show blue emission (CIE coordinates: (0.14, 0.26)). The brightness of the device reaches 10000 cd/m2 at 9.5 V. The maximum external quantum efficiency (EQE) was 19.2% at 1000 cd/m2
