| 研究課題/領域番号 |
15K05413
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| 研究機関 | 筑波大学 |
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研究代表者 |
Lee Vladimir 筑波大学, 数理物質系, 講師 (90375410)
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| 研究期間 (年度) |
2015-04-01 – 2018-03-31
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| キーワード | cluster / group 14 element / group 15 element / housene / pyramidane / cyclobutadiene dianion / NMR spectroscopy / X-Ray crystallography |
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| 研究実績の概要 |
The goal of this project is the development of new synthetic approaches for the preparation of a novel class of the highly strained polyhedral clusters, pyramidanes, pyramidal compounds of the heavier main group elements.
Given their non-classical structures, pyramidanes are very interesting objects for the fundamental studies, both experimental and computational, to reveal their peculiar structural features and unusual bonding situations. On the other hand, pyramidanes could serve as very promising precursors for novel type of ceramics and nanostructural objects in material science.
In accord with the initially proposed plan, during the second year of the project we successfully synthesized a series of the cationic pyramidanes with the heavier group 15 element (P, Sb, Bi) at the apex of the square-pyramid. These target compounds were prepared by the straightforward reaction of the readily available cyclobutadiene and tetrasilacyclobutadiene dianion derivatives with the group 15 element halides EX3 (E = group 15 element). Reaction conditions (solvents, temperature, ratio of reagents) were optimized to maximize the yields of target pyramidanes. The structures of all pyramidanes were thoroughly studied both experimentally (X-Ray, NMR) and computationally (high-level DFT calculations), and then compared with those of their heavier group 14 element analogues.
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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
During the second year of the project, all plans were successfully fulfilled and all synthetic targets were realized. As was originally planned, the target cationic pyramidanes were prepared by the coupling reaction of the readily available cyclobutadiene dianion derivatives and group 15 element halides followed by the oxidative dehalogenation of the initially formed (halo)housenes. Accordingly, a whole series of the cationic hybrid group 14/group 15 element pyramidanes E'[E4(SiR3)4] (E' = group 15 element, E = group 14 element) was synthesized, fully structurally characterized, and comprehensively computationally studied.
Thus, during its second year, the project was running very smoothly with no any troubles, according to the originally proposed research plans and schedule.
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| 今後の研究の推進方策 |
During the third year of the project, we will focus on the synthesis of anionic hybrid group 13/group 14 element pyramidanes E'[E4(SiR3)4] (E' = group 13 element, E = group 14 element) which could be prepared by the reaction of cyclobutadiene dianion derivatives and group 13 element halides followed by the reductive dehalogenation of the initially formed (halo)housenes. The structures of these anionic pyramidanes will be thoroughly studied, both experimentally and theoretically.
Finally, the reactivity of all prepared pyramidanes (neutral, cationic, anionic) will be investigated towards their practical use in the synthetic organometallic chemistry and their application in material science as the promising precursors for the new advanced materials.
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| 次年度使用額が生じた理由 |
For the second year of the project, the originally proposed and actually used money to purchase equipment and chemical reagents were nearly the same, 900000 yen vs. 863470 yen. However, some money remaining after the first year of the project were transferred to the second year (955385 yen) These money were partially used for the conference traveling to attend very important major international symposiums abroad where invited plenary lectures were delivered. That is why the amount for traveling is greater than was originally planned.
After the second year of the project, the remaining amount was 266621 yen.
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| 次年度使用額の使用計画 |
The amount of money remaining after the second year of the project will be used within the third year of the project to purchase chemical reagents necessary to fulfill the research goals and perform the required experimental work. The successful realization of the research plan of the third year of the project requires the use of such reagents.
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