Longest C-C Single Bond among Neutral Hydrocarbons with a Bond Length beyond 1.8 angstrom
| Autor: | Takashi Takeda, Ryo Katoono, Yusuke Ishigaki, Takuya Shimajiri, Takanori Suzuki |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Eclipsed conformation
hexaphenylethane Materials science General Chemical Engineering extreme structure scissor effect DFT calculation 010402 general chemistry 01 natural sciences Biochemistry Ring strain chemistry.chemical_compound Hexaphenylethane Materials Chemistry Environmental Chemistry Single bond strained hydrocarbon 010405 organic chemistry Diradical Biochemistry (medical) long bond General Chemistry polycyclic hydrocarbons 0104 chemical sciences Bond length Crystallography core-shell chemistry Covalent bond Intramolecular force Raman spectroscopy X-ray analysis |
| Zdroj: | Chem. 4(4):795-806 |
| ISSN: | 2451-9294 |
| Popis: | Summary On the basis of the intramolecular "core-shell strategy," we designed dihydropyracylene with two spiro(dibenzocycloheptatriene) units, for which theoretical calculations predicted a very weak C–C bond with a bond length around 1.8 A. This bond is expanded by the forced adoption of an eclipsed conformation and by angle strain through a "scissor effect." The highly strained hydrocarbon was isolated as a thermally stable compound with no signs of diradical contribution because the weak C–C bond (core) is protected by the shape-persistent fused-ring structure (shell). A Raman shift corresponding to the C–C stretching vibration (587 cm −1 ) was very different from that for ethane (993 cm −1 ). The bond length determined by X-ray (1.806(2) A) was greater than the shortest non-bonded intramolecular C … C contact (1.80(2) A). The assumed limit for a C–C bond (1.803 A) by supposing linear correlation between bond length and bond-dissociation energy for covalent bonding was proven to be invalid. |
| Databáze: | OpenAIRE |
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