A Pentacene with a 144 Twist
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- 作者：Jun Lu ; Douglas M. Ho ; Nancy J. Vogelaar ; Christina M. Kraml ; and Robert A. Pascal ; Jr.
- 刊名：Journal of the American Chemical Society
- 出版年：2004
- 出版时间：September 15, 2004
- 年：2004
- 卷：126
- 期：36
- 页码：11168 - 11169
- 全文大小：76K
- 年卷期：v.126,no.36(September 15, 2004)
- ISSN：1520-5126
文摘
9,10,11,20,21,22-Hexaphenyltetrabenzo[a,c,l,n]pentacene (1) was prepared by the reaction of 1,3-diphenylphenanthro[9,10-c]furan with the bisaryne equivalent generated from 1,2,4,5-tetrabromo-3,6-diphenylbenzene in the presence of n-butyllithium, followed by deoxygenation of the double adduct with low-valent titanium. The X-ray structure of 1 shows it to be the most highly twisted polycyclic aromatic hydrocarbon known, with an end-to-end twist of 143.6
. Compound 1 was resolved by chromatography on a chiral support, and the pure enantiomers have specific rotations in excess of 7000, but the molecule racemizes slowly at 25 C (t1/2 = 9.3 h, 
G
rac = 23.8 kcal/mol).
. Compound 1 was resolved by chromatography on a chiral support, and the pure enantiomers have specific rotations in excess of 7000, but the molecule racemizes slowly at 25 C (t1/2 = 9.3 h, Grac = 23.8 kcal/mol).