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Design and Synthesis of a Coumarin-based Acidichromic Colorant
Department of Chemistry and Center for Nanoscience and Technology, Tunghai University, 181, Taichung-Kang Rd. Sec.3, Taichung, Taiwan 407
* Author to whom correspondence should be addressed.
Received: 6 June 2007; in revised form: 1 July 2007 / Accepted: 1 July 2007 / Published: 6 July 2007
Abstract: This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electron-withdrawing substituents on the coumarin moiety. Colorant 1 can undergo two distinct and reversible color changes under both strongly acidic and basic conditions, but not in the presence of gaseous ammonia. The results indicated that the bromo-substituted compound 5b changes from red to yellow when exposed to gaseous ammonia, both in solution and on polycarbonate film, suggesting that an electron-withdrawing group at the 7-position of the coumarin moiety made the enolic hydrogen on 5b more susceptible to deprotonation by a base than in the unsubstituted compound 1.
Keywords: Coumarin; triketone; acidichromism; gas sensor; acid-base sensor
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Lin, S.-L.; Kuo, P.-Y.; Yang, D.-Y. Design and Synthesis of a Coumarin-based Acidichromic Colorant. Molecules 2007, 12, 1316-1324.
Lin S-L, Kuo P-Y, Yang D-Y. Design and Synthesis of a Coumarin-based Acidichromic Colorant. Molecules. 2007; 12(7):1316-1324.
Lin, Shih-Lun; Kuo, Pei-Yu; Yang, Ding-Yah. 2007. "Design and Synthesis of a Coumarin-based Acidichromic Colorant." Molecules 12, no. 7: 1316-1324.