| 研究課題/領域番号 |
26810041
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| 研究機関 | 独立行政法人理化学研究所 |
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研究代表者 |
HU SHAOWEI 独立行政法人理化学研究所, 環境資源科学研究センター, 特別研究員 (30713036)
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| 研究期間 (年度) |
2014-04-01 – 2016-03-31
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| キーワード | C-C bond cleavage / benzene / titanium polyhydride |
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| 研究実績の概要 |
Aromatic compounds are widely found in natural resources such as petroleum and biomass, and breaking them into smaller hydrocarbon fragments plays an important role in the production of fuels and valuable chemicals. However, carbon-carbon bonds of aromatic compounds are very stable and difficult to break under ordinary conditions. We found the C-C bond cleavage and rearrangement of benzene by a trinuclear titanium polyhydride complex. A benzene ring can be transformed sequentially to methylcyclopentenyl and 2-methylpentenyl species through hydrogenating and breaking the aromatic carbon skeleton at the multi-titanium sites. It is the first example of carbon-carbon bond cleavage and rearrangement of benzene by a well-defined molecular system. These findings demonstrate that multinuclear titanium hydrides can serve as a unique platform for the activation of aromatic molecules, and may help design and construct new catalysts for more efficient and selective production of useful materials from natural resources.So far, part of this research result has been published on Nature in 2014.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
So far we have investigated the fundamental aspects of this C-C bond cleavage and skeletal rearrangement reactions of benzene promoted by trinuclear titanium heptahydride complex. We have explored and characterized all the reaction products and isolated the key intermediate in the transformation. This results has been published in Nature. Besides, we are now cooperating with some specialist in computation area to clarify the detailed mechanisms of this cleavage and transformation of the extremely inert aromatic rings. Currently the collection of the data has been completed and manuscript is under preparation.
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| 今後の研究の推進方策 |
In the future, we will focus our research in the liberation of the activated carbon unit and make catalytic cycle for the transformation of aromatic hydrocarbons to isomerized compounds.
a.through hydrogenolysis reactions.
b.through reaction with hydride reagent (for organic synthesis).
Further elaboration of the catalytic reaction mechanisms will be conducted (through monitoring the reactions and isolating the key intermediates) as well.
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| 次年度使用額が生じた理由 |
Last fiscal year we have investigated the stoichiometric reactions of aromatic molecule activation including the structure characterization and processes analysis. However, the conferences expense and the reagents cost are not as much as we expected at early time, and at same time we have't bought some apparatus because the research progress is not as scheduled. So we apply to move the rest of the kakenhi to the next year. For the further research, we will explore the catalytic reactions to liberate the activated carbon fragment through using H2 or some simple hydride reagents. These studies definitely need more input, no matter for reagents, glasswares or high pressure apparatus.
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| 次年度使用額の使用計画 |
Catalytic transformation of aromatic hydrocarbons to isomerized cycloalkanes or branched alkanes will be developed.
Based on the results in last fiscal year, attempts to achieve catalytic transformation of aromatic hydrocarbons to isomerized compounds will be conducted. The carbon skeletal from benzene activation by titanium hydride complex will be liberated to afford methylcyclopentane or iso-hexane (or substituted methylcyclopentane) through hydrogenolysis (or addition of simple hydride reagent) under mild conditions. Other aromatic substrates will also be checked,such as toluene, xylene and naphthalene.The reaction mechanism will be elucidated through NMR monitoring and isolating key intermediates.
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