Thermal single crystal to single crystal transformation among crystal polymorphs in 2-dimethylamino-5,7-bis(trifluoromethyl)-1,8-naphthyridine and in a 1-quinoline analogue

Naomi Harada, Satoru Karasawa, Taisuke Matsumoto, Noboru Koga

研究成果: ジャーナルへの寄稿学術誌査読

30 被引用数 (Scopus)

抄録

2-Dimethylamino-5,7-bis(trifluoromethyl)-1,8-naphthyridine 1 was prepared as a new solid-state fluorophore. Recrystallization of 1 from CH 2Cl2/n-hexane afforded three crystal polymorphs, G, BM, and BO, with the space group (crystal class) C2/c (monoclinic), P21/c (monoclinic), and Pbca (orthorhombic), respectively, at 23 C. DSC curves for G showed one endothermic peak at 110 C in the high temperature region and two pairs of endo- and exothermic peaks at ca. 18 and 7 C in the low temperature region, which were assigned as crystal phase transitions. In the high temperature region, a reversible transformation from G to B (a mixture of BM and BO) by heating at 110 C and from B to G by grinding was observed with alteration of the emitted color. In the low temperature region, X-ray crystallography suggested that G transformed to G2 (10 C) and G4 (-50 C) with a subtle alteration of molecular arrangements through thermal single crystal to single crystal interconversion. Eventually, 1 provided five crystal polymorphs, G, G2, G4, BM, and BO, containing eight crystallographically independent molecules. In contrast, the 1-quinoline analogue, 2, provided two crystal polymorphs, 2α (23 C) and 2β (-123 C).

本文言語英語
ページ(範囲)4705-4713
ページ数9
ジャーナルCrystal Growth and Design
13
11
DOI
出版ステータス出版済み - 11月 6 2013

!!!All Science Journal Classification (ASJC) codes

  • 化学 (全般)
  • 材料科学(全般)
  • 凝縮系物理学

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