Design and Synthesis of a Coumarin-based Acidichromic Colorant

Shih-Lun Lin, Pei-Yu Kuo, Ding-Yah Yang
2007 Molecules  
This paper describes the fine-tuning of the acidichromic properties of a coumarin-containing colorant 1 by incorporation of electron-donating and electronwithdrawing 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
more » ... , 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.
doi:10.3390/12071316 pmid:17909487 fatcat:vljvl4q3kvexzgtjz5ph7hpqwy