Synthesis, Structures, and Properties of Hexapole Helicenes: Assembling Six [5]Helicene Substructures into Highly Twisted Aromatic Systems.
Hexapole helicenes 1, which contain six [5]helicene substructures, were synthesized by Pd-catalyzed [2+2+2]- cycloadditions of aryne precursor 6. Among the possible 20 stereoisomers, which include ten pairs of enantiomers, HH-1 was obtained selectively. Density functional theory (DFT) calculations i...
| Publicado en: | Journal of the American Chemical Society Vol. 139; no. 51; pp. 18512 - 18522 |
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| Autores principales: | , , , , , , , |
| Formato: | Artículo |
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American Chemical Society
12/27/2017
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=127082115&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 127082115 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 12/27/2017 vid: 139 iid: 51 pid: 997 pub: American Chemical Society artinfo: ui: 127082115 10.1021/jacs.7b07113 ppf: 18512 ppct: 10 formats: tig: atl: Synthesis, Structures, and Properties of Hexapole Helicenes: Assembling Six [5]Helicene Substructures into Highly Twisted Aromatic Systems. aug: au: Hosokawa, Tomoka Takahashi, Yusuke Matsushima, Tomoya Watanabe, Soichiro Kikkawa, Shoko Azumaya, Isao Tsurusaki, Akihiro Kamikawa, Ken affil: Department of Chemistry, Graduate School of Science, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan Department of Biomolecular Science, Faculty of Science, and Research Center for Materials with Integrated Properties, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan su: Helicenes Chemical structure Chemical synthesis X-ray diffraction Density functional theory Electrochemical analysis Isomers sug: subj: Helicenes Chemical structure Chemical synthesis X-ray diffraction Density functional theory Electrochemical analysis Isomers ab: Hexapole helicenes 1, which contain six [5]helicene substructures, were synthesized by Pd-catalyzed [2+2+2]- cycloadditions of aryne precursor 6. Among the possible 20 stereoisomers, which include ten pairs of enantiomers, HH-1 was obtained selectively. Density functional theory (DFT) calculations identified HH-1 as the second most stable isomer that quantitatively isomerizes under thermal conditions into the most stable isomer (HH-2). Both enantiomers of HH-2 can be separated by chiral HPLC. Single-crystal X-ray diffraction analyses revealed a saddle-like structure for (P,M,P,P,M,P) HH-1 and a propeller-like structure for (P,M,P,M,P,M) HH-2. Because of the helical assembly and the resulting steric repulsion, the structure of HH-1 is significantly distorted and exhibits the largest twisting angle reported so far (up to 35.7° per benzene unit). Electrochemical studies and DFT calculations indicated a narrow HOMO-LUMO gap on account of the extended π-system. Kinetic studies of the isomerization from HH-1 to HH-2 and the racemization of enantiomerically pure HH-2 were conducted based on 1H NMR spectroscopy, HPLC analysis, and DFT calculations. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2017 holdings: @attributes: islocal: N |
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