Synthesis, Structures, and Properties of π-Extended Double Helicene: A Combination of Planar and Nonplanar π-Systems
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- Takao Fujikawa
- Graduate School of Science, ‡JST, ERATO, Itami Molecular Nanocarbon Project, and §Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya 464-8602, Japan
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- Yasutomo Segawa
- Graduate School of Science, ‡JST, ERATO, Itami Molecular Nanocarbon Project, and §Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya 464-8602, Japan
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- Kenichiro Itami
- Graduate School of Science, ‡JST, ERATO, Itami Molecular Nanocarbon Project, and §Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Nagoya 464-8602, Japan
書誌事項
- 公開日
- 2015-06-11
- 資源種別
- journal article
- DOI
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- 10.1021/jacs.5b03118
- 公開者
- American Chemical Society (ACS)
この論文をさがす
説明
The synthesis, structures, and properties of a π-extended double helicene 1 are described. This double helicene 1 was synthesized by a four-fold oxidative C-H biphenylation of naphthalene followed by the Scholl reaction or via five steps including the Suzuki-Miyaura cross-coupling reaction and the Scholl reaction. Due to the two helical substructures, 1 has three isomers, i.e., two enantiomers in a twisted form [(P,P) and (M,M)] and one diastereoisomer in a meso form. X-ray crystallographic analysis of the twisted isomers (twisted-1) revealed a tightly offset packing pattern of (P,P)- and (M,M)-twisted isomers, affording a three-dimensional lamellar stacking structure. A high isomerization barrier (43.5 kcal mol(-1)) and the relative thermal stability of twisted-1 isomer over meso-1 by 0.9 kcal mol(-1) were estimated by DFT calculations. The three isomers were successfully separated by chiral HPLC and characterized by circular dichroism spectroscopy as well as by TD-DFT studies. Electronic state variation resulting from the molecular geometry difference between the two diastereoisomers (twisted-1 and meso-1) was observed by UV-vis absorption and fluorescence spectra.
収録刊行物
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- Journal of the American Chemical Society
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Journal of the American Chemical Society 137 (24), 7763-7768, 2015-06-11
American Chemical Society (ACS)