2008年7月
Structural properties and degree of intramolecular charge transfer of an N-alkyl indoline-tricyanoquinodimethane system
BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN
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- 巻
- 81
- 号
- 7
- 開始ページ
- 869
- 終了ページ
- 884
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1246/bcsj.81.869
- 出版者・発行元
- CHEMICAL SOC JAPAN
A series of intramolecular charge-transfer compounds comprised of 1-alkyl-3,3-dimethyl-2-methyleneindoline (I-n, donor, n = alkyl chain length; 1-8, 10, 14, 16, 18, 20, and 22) and 7,8,8-tricyanoquinodimethane (=2-(4'-cyanomethylene-2'.5'-cyclohexadienylidene)malononitrile (3CNQ), acceptor) moieties linked through a pi-bond, I-n-3CNQ were prepared. and their structures are discussed. The melting points of the I-n-3CNQ solids decreased with increasing alkyl chain length until reaching a minimum point (95 degrees C) at n = 18, and then began to gradually increase, indicating self-aggregation of the alkyl chains. The I-n-3CNQ derivatives with long alkyl chains (n >= 6) produced supercooled liquids displaying conspicuous color changes after melting. Diverse molecular packing patterns were observed in the crystal structures. Most I-n-3CNQ derivatives formed face-to-face and/or side-by-side dimeric motif's to cancel net dipole moments. I-20-3CNQ formed a two-dimensional bilayer structure by pi-stacking and self-assembly of the alkyl chains. Two types of molecular conformation, which significantly affect the electronic structures, were observed to be dependent on the alkyl chain length. A parameter to evaluate the degree of intramolecular charge transfer, namely bond length ratio, was proposed: it exhibited good agreement with solvatochromic shifts and molecular orbital calculations.
- リンク情報
- ID情報
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- DOI : 10.1246/bcsj.81.869
- ISSN : 0009-2673
- eISSN : 1348-0634
- CiNii Articles ID : 10021076916
- Web of Science ID : WOS:000258738600010