title: Cavity-Directed Chromism of Phthalein Dyes.
abstract: Phthalein dyes in the quinone dianion form (pseudo-D3, colored) are transformed into the lactone dianion form (pseudo-T(d), colorless) through encapsulation in a T(d)-symmetric host even under basic conditions (pH ∼10). The compatibility in size and symmetry between the lactone and the cavity is essential to the transformation. Upon addition of a guest that strongly binds to the cavity, the encapsulated phenolphthalein is expelled, the color of the basic solution is regained, and the host-guest complexation is thus visualized.
authors.affiliation: †Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Takezawa
authors.affiliation: †Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Shouta
authors.initials: S
authors.lastname: Akiba
authors.affiliation: ‡Department of Material and Biological Chemistry, Faculty of Science, Yamagata University, 1-4-12 Kojirakawa-machi, Yamagata-shi, Yamagata 990-8560, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Murase
authors.affiliation: †Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Fujita