Oxidized Bis(indolyl)methane: A Simple and Efficient Chromogenic-Sensing Molecule Based on the Proton Transfer Signaling Mode

Abstract
Oxidized bis(indolyl)methane, 1, a simple chromophore containing an acidic H-bond donor moiety and a basic H-bond acceptor moiety, can act as a selective colorimetric sensor either for F- in aprotic solvent or for HSO4- and weak acidic species in water-containing medium. The deprotonation/protonation of oxidized bis(indolyl)methane 1 is responsible for the dramatic color change.