A spiropyran derivative containing a dinitrophenolate moiety (2: 1′, 3′, 3′-trimethyl-6, 8- dinitro-spiro-[2H-1-benzopyran-2, 2′-indoline]) behaves as a receptor for selective detection of cyanide anion (CN−) in aqueous media. Compound 2, when dissolved in aqueous media, spontaneously produces the spirocycle-opened merocyanine (MC) form even in dark condition. The absorption band of the MC form decreases selectively upon ...
[Keum, Sam-Rok; Lee, Ki-Bong; Kazmaier, Peter M.; Manderville, Richard A.; Buncel, Erwin Magnetic Resonance in Chemistry, 1992 , vol. 30, # 11 p. 1128 - 1131]