| Project/Area Number |
11640537
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Organic chemistry
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| Research Institution | Okayama University of Science |
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Principal Investigator |
TODA Fumio Okayama University of Science Professor, 理学部, 教授 (50036232)
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| Co-Investigator(Kenkyū-buntansha) |
TANAKA Koichi Ehime University Associate Professor, 工学部, 助教授 (10116949)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | naphthocyclobutenes / extremely long C - C bond / steric repulsion / through bond interaction / anthradicyclobutenes / phenanthradicyclobutenes / 最も長い炭素-炭素結合 / 立体的効果 / 電子的効果 / スル-ボンド相互作用 |
|---|
| Research Abstract |
Some naphthocyclobutenes substituted with four phenyl groups and with two phenyl and two t Bu groups are prepared. X-ray analysis of these naphthocyclobutenes showed that the cyclobutene C - C bonds are extremely long, 1.72 - 1.73 Å. Especially, the C - C cyclobutene bond of the naphthocyclobutene substituted with two phenyl and two t Bu groups is the longest 1.73 Å. π-Electron locarization in the naphthalene ring is also observed.
Reason for the extremely long C - C bond in naphthocyclobutenes would be a steric repulsion among bulky substituents on the four-membered ring. There is one another possible reason, namely, through bond interaction. In order to clarify which reason is more important, naphthocyclobutene derivatives substituted with cis- and trans-diphenyl groups were prepared. X-ray structural analysis of these showed there is no big difference between the bond length of cis- and trans-isomers. These results suggest that the steric repulsion is more important factor.
Similarly, anthradicyclobutenes and phenanthradicyclobutenes substituted with phenyl groups were prepared. X-ray structural analysis of these showed that the cyclobutene C - C bonds are also extremely long. Stabilities of these cyclobutane derivatives would be due to the following reasons : ring opening of the cyclobutene should produce sterically crowded biradical or resonance energy lost quinodimethane.
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