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Takayuki Kawashima - One of the best experts on this subject based on the ideXlab platform.
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Regioselective and Stereospecific Dehydrogenative Annulation Utilizing Silylium Ion-Activated Alkenes.
The Journal of organic chemistry, 2016Co-Authors: Hidekazu Arii, Yuto Yano, Kenichi Nakabayashi, Syuhei Yamaguchi, Masaki Yamamura, Kunio Mochida, Takayuki KawashimaAbstract:Treatment of dialkylbenzylsilanes (1) with trityl tetrakis(pentafluorophenyl)borate (TPFPB) afforded the corresponding silylium ions in equilibrium with their intra- or intermolecular π-complexes, which underwent dehydrogenative annulation with various alkenes to form 1,2,3,4-tetrahydro-2-silanaphthalenes (4) in up to 82% isolated yield. Sterically bulkier substituents on the silicon atom tended to increase the yield of cyclic products 4. The annulation products retained the stereochemistry in cases of the reactions using internal alkenes. The use of diisopropyl(1-Naphthyl)silane (2) instead of 1 also resulted in annulation to obtain the 2,3-dihydro-1-sila-1H-phenalene derivatives 6. Electrophilic aromatic substitution at the 8-position was predominant, despite the two potentially reactive positions on the Naphthyl Group. The steric hindrance of the Naphthyl Group prevented addition of the cis-alkene to the silylium ion, which would considerably decrease yields of the desired products from 2 compared to t...
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Regioselective and Stereospecific Dehydrogenative Annulation Utilizing Silylium Ion-Activated Alkenes
2016Co-Authors: Hidekazu Arii, Yuto Yano, Kenichi Nakabayashi, Syuhei Yamaguchi, Masaki Yamamura, Kunio Mochida, Takayuki KawashimaAbstract:Treatment of dialkylbenzylsilanes (1) with trityl tetrakis(pentafluorophenyl)borate (TPFPB) afforded the corresponding silylium ions in equilibrium with their intra- or intermolecular π-complexes, which underwent dehydrogenative annulation with various alkenes to form 1,2,3,4-tetrahydro-2-silanaphthalenes (4) in up to 82% isolated yield. Sterically bulkier substituents on the silicon atom tended to increase the yield of cyclic products 4. The annulation products retained the stereochemistry in cases of the reactions using internal alkenes. The use of diisopropyl(1-Naphthyl)silane (2) instead of 1 also resulted in annulation to obtain the 2,3-dihydro-1-sila-1H-phenalene derivatives 6. Electrophilic aromatic substitution at the 8-position was predominant, despite the two potentially reactive positions on the Naphthyl Group. The steric hindrance of the Naphthyl Group prevented addition of the cis-alkene to the silylium ion, which would considerably decrease yields of the desired products from 2 compared to those from 1
Hidekazu Arii - One of the best experts on this subject based on the ideXlab platform.
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Regioselective and Stereospecific Dehydrogenative Annulation Utilizing Silylium Ion-Activated Alkenes.
The Journal of organic chemistry, 2016Co-Authors: Hidekazu Arii, Yuto Yano, Kenichi Nakabayashi, Syuhei Yamaguchi, Masaki Yamamura, Kunio Mochida, Takayuki KawashimaAbstract:Treatment of dialkylbenzylsilanes (1) with trityl tetrakis(pentafluorophenyl)borate (TPFPB) afforded the corresponding silylium ions in equilibrium with their intra- or intermolecular π-complexes, which underwent dehydrogenative annulation with various alkenes to form 1,2,3,4-tetrahydro-2-silanaphthalenes (4) in up to 82% isolated yield. Sterically bulkier substituents on the silicon atom tended to increase the yield of cyclic products 4. The annulation products retained the stereochemistry in cases of the reactions using internal alkenes. The use of diisopropyl(1-Naphthyl)silane (2) instead of 1 also resulted in annulation to obtain the 2,3-dihydro-1-sila-1H-phenalene derivatives 6. Electrophilic aromatic substitution at the 8-position was predominant, despite the two potentially reactive positions on the Naphthyl Group. The steric hindrance of the Naphthyl Group prevented addition of the cis-alkene to the silylium ion, which would considerably decrease yields of the desired products from 2 compared to t...
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Regioselective and Stereospecific Dehydrogenative Annulation Utilizing Silylium Ion-Activated Alkenes
2016Co-Authors: Hidekazu Arii, Yuto Yano, Kenichi Nakabayashi, Syuhei Yamaguchi, Masaki Yamamura, Kunio Mochida, Takayuki KawashimaAbstract:Treatment of dialkylbenzylsilanes (1) with trityl tetrakis(pentafluorophenyl)borate (TPFPB) afforded the corresponding silylium ions in equilibrium with their intra- or intermolecular π-complexes, which underwent dehydrogenative annulation with various alkenes to form 1,2,3,4-tetrahydro-2-silanaphthalenes (4) in up to 82% isolated yield. Sterically bulkier substituents on the silicon atom tended to increase the yield of cyclic products 4. The annulation products retained the stereochemistry in cases of the reactions using internal alkenes. The use of diisopropyl(1-Naphthyl)silane (2) instead of 1 also resulted in annulation to obtain the 2,3-dihydro-1-sila-1H-phenalene derivatives 6. Electrophilic aromatic substitution at the 8-position was predominant, despite the two potentially reactive positions on the Naphthyl Group. The steric hindrance of the Naphthyl Group prevented addition of the cis-alkene to the silylium ion, which would considerably decrease yields of the desired products from 2 compared to those from 1
Huanli Dong - One of the best experts on this subject based on the ideXlab platform.
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Substitution site effect of Naphthyl substituted anthracene derivatives and their applications in organic optoelectronics
Journal of Materials Chemistry C, 2020Co-Authors: Mingxi Chen, Jinyu Liu, Zhengsheng Qin, Yajing Sun, Yangyang Dang, Yonggang Zhen, Huanli DongAbstract:By introducing the Naphthyl Group into the 2,6-positions of anthracene, two different anthracene derivatives, 2,6-di(2-Naphthyl)anthracene (2,6-di(2-Na)Ant) and 2,6-di(1-Naphthyl)anthracene (2,6-di(1-Na)Ant) were synthesized. The tiny change in the substitution site of the Naphthyl Group leads to a significant difference in the molecular packing and further exerts a great impact on their optoelectronic properties. Thin film field-effect transistors for 2,6-di(2-Na)Ant show charge transport mobility up to 2.1 cm2 V−1 s−1, while 2,6-di(1-Na)Ant demonstrates no mobility. Moreover, thin film phototransistors of 2,6-di(2-Na)Ant show a photoresponsivity of 6.9 × 103 A W−1, a high photosensitivity of 2.6 × 106 and an excellent detectivity of 3.4 × 1016 Jones, which is one of the highest performances of thin film organic phototransistors reported to date.
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Naphthyl substituted anthracene combining charge transport with light emission
Journal of Materials Chemistry C, 2015Co-Authors: Jie Liu, Yonggang Zhen, Lingqiang Meng, Ying Wang, Huanli DongAbstract:By simply introducing the Naphthyl Group into the 2-position of anthracene, we synthesized a new anthracene derivative, NaAnt, which showed good charge transporting properties up to 1.10 cm2 V−1 s−1 and a photoluminescence quantum yield (PLQY) of 40.30%. The results indicate its potential applications in multifunctional optoelectronics.
Kohei Tamao - One of the best experts on this subject based on the ideXlab platform.
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generation of intramolecular sulfur or selenium coordinated silylenes by the thermolysis of pentacoordinate disilanes bearing an 8 thio or 8 seleno 1 Naphthyl Group and a methoxy Group on the same silicon atom
Organometallics, 2003Co-Authors: Tomoyuki Saeki, And Akio Toshimitsu, Kohei TamaoAbstract:Pentacoordinate disilanes bearing an 8-thio- or 8-seleno-1-Naphthyl Group and a methoxy Group on the same silicon center undergo thermal degradation to generate intramolecular sulfur- or selenium-coordinated silylenes. The chalcogen-coordinated silylenes behave as nucleophilic sila-ylides during the reaction with diphenylacetylene to afford a silacyclopropene and, in the case of selenium, a silaphenalene as intermediates.
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Trapping of ammonium sila-ylide with pentaphenylfulvene or dibenzofulvene
Silicon Chemistry, 2003Co-Authors: Tomoyuki Saeki, Akio Toshimitsu, Kohei TamaoAbstract:The thermolysis of a pentacoordinate fluorodisilane bearing an 8-(dimethylamino)-1-Naphthyl Group in the presence of 2,3,4,5,6-pentaphenylfulvene or 14-phenyldibenzofulvene affords a silylene-fulvene adduct bearing a zwitterionic structure attributable to the silaylide, but it spontaneously undergoes subsequent intramolecular cyclization reaction between the silicon atom and the aromatic carbon atom in the fulvene moiety followed by a sigmatropic proton migration to form a neutral silicon-containing six- or five-membered ring product.
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preparation structure and reactivity of pentacoordinate disilanes bearing an 8 charcogeno 1 Naphthyl Group and a heteroatom on the same silicon atom
Heteroatom Chemistry, 2001Co-Authors: Akio Toshimitsu, Masahiro Asahara, Tomoyuki Saeki, Shino Hirao, Kohei TamaoAbstract:The pentacoordinate disilanes bearing an 8-chalcogeno-1-Naphthyl Group and an ethoxy Group (or a fluorine atom) on the same silicon center are found to be thermally stable, in sharp contrast to the thermal lability of the analogous disilanes coordinated by the Group 15 elements, such as nitrogen and phosphorus, to α-elimination of the ethoxysilane (or fluorosilane) to generate the base-coordinated silylenes. As the reasons for this different behavior, two possibilities are pointed out as follows: (1) the nitrogen-coordinated disilanes are destabilized due to the distortion of the Naphthyl moiety, and (2) silylenes are more stabilized by coordination with the Group 15 elements than with the Group 16 elements. © 2001 John Wiley & Sons, Inc. Heteroatom Chem 12:392–397, 2001
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Trimerization of a Divalent Silicon Species Bearing the 8-Dimethylamino-1-Naphthyl Group Accompanied by the Migration of Methyl and Dimethylamino Groups
Chemistry Letters, 2000Co-Authors: Kohei Tamao, Masahiro Asahara, Akio ToshimitsuAbstract:A divalent silicon species bearing the 8-(dimethylamino)-1-Naphthyl Group trimerizes to afford a 1,2-disilaacenaphthene framework incorporated in a trisilane chain and accompanied by the migration of the methyl and dimethylamino Groups.
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Nucleophilic Addition of a Divalent Silicon Species Bearing the 8-Dimethylamino-1-Naphthyl Group to Diphenylacetylenes to Form the 1-Amino-1-silaphenalene Skeleton
Chemistry Letters, 2000Co-Authors: Kohei Tamao, Masahiro Asahara, Tomoyuki Saeki, Shengyu Feng, Atsushi Kawachi, Akio ToshimitsuAbstract:A 1-amino-1-silaphenalene skeleton is formed by the reaction of a divalent silicon species bearing the 8-(dimethylamino)-1-Naphthyl Group with diphenylacetylene via an alkenyl anion intermediate.
Tatsuo Arai - One of the best experts on this subject based on the ideXlab platform.
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photochromism thermochromism and solvatochromism of naphthalene based analogues of salicylideneaniline in solution
Journal of Photochemistry and Photobiology A-chemistry, 2004Co-Authors: Asuka Ohshima, Atsuya Momotake, Tatsuo AraiAbstract:Abstract A series of salicylideneaniline ( SA ) derivatives 1–3 were prepared to study the substituent effect on the chromic properties. Compounds 1 and 3 , introduced Naphthyl Group on the A ring in the parent compound SA , exhibited the solvatochromism, thermochromism and photochromism, while compound 2 , introduced the Naphthyl Group on the B ring in SA , did not show the solvatochromism or thermochromism. The discussion in this study is mainly focused on the behaviour of compounds 1 and 2 . The UV absorption spectra of 1 dramatically changed with increasing the solvent polarity as well as cooling temperature, suggesting that 1 takes Z -NH form in polar solvents at room temperature or even in non-polar solvents at below 120 K. Compound 1 emits fluorescence (FL) only at low temperature with small Stokes shift, while 2 exhibits fluorescence emission with considerably large Stokes shift. On UV irradiation, 1 in benzene underwent intramolecular hydrogen atom transfer to give E -NH form. The large Stokes shift observed in 2 indicates that 2 takes E -OH form even at low temperature in any solvents, and underwent intramolecular hydrogen atom transfer in the excited state to give Z -NH form, which emits the fluorescence at low temperature, or undergoes isomerization around CC double bond to give E -NH form. The potential energy diagrams for 1 and 2 were also determined.
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Effects of β-substituents on internal rotation of the anthryl Group of 2-anthrylethylenes in the excited singlet state
Journal of Photochemistry and Photobiology A: Chemistry, 1992Co-Authors: Tatsuo Arai, Hirochika Sakuragi, Katsumi Tokumaru, Takashi Karatsu, Naoto Tamai, Iwao YamazakiAbstract:Abstract 2-Vinylanthracene and its β-alkyl derivatives undergo, in the excited singlet state, almost one-way rotational isomerization around the single bond connecting the anthracene nucleus and CC double bond, while no rotational isomerization takes place for 2-anthrylethylenes with a phenyl or 2-Naphthyl Group in the β-position.
