A colorimetric chemosensor for both fluoride and transition metal ions based on dipyrrolyl derivative was written by Ghosh, Tamal;Maiya, Bhaskar G.;Samanta, Anunay. And the article was included in Dalton Transactions in 2006.Reference of 322-46-3 This article mentions the following:
The synthesis, characterization and ion binding studies of 2,3-di(1H-2-pyrrolyl)pyrido[2,3-b]pyrazine (1) were described. Compound 1, which was targeted with a view to sensing both F– and transition metal ions, exhibits binding-induced color changes from yellowish green to red/brown observable by the naked eye. The binding site for the metal ion in the system was unambiguously established by single-crystal x-ray diffraction study of a Ni(II) complex of 1. While the estimated value of the binding constant of 1 with F– is 4.9 × 103 M-1, the binding constants for the cations are two orders higher in magnitude in acetonitrile. Even though 1 possesses two sep. binding sites for F– and metal ions, the presence of the cation influences the binding of the anion and vice versa. The binding constant values of an ion in the presence of oppositely charged species are significantly lower. In the experiment, the researchers used many compounds, for example, Pyrido[2,3-b]pyrazine (cas: 322-46-3Reference of 322-46-3).
Pyrido[2,3-b]pyrazine (cas: 322-46-3) belongs to pyrazine derivatives. Pyrazine heterocycles and their benzo derivatives possess many interesting properties, including chemical reactivity profiles, and have diverse applications in total synthesis, medicine, chemical biology, materials, dyes, and imaging. Pyrazines undergo nearly all of the same reactions as pyrimidines, from nucleophilic substitution (SNAr) to palladium-catalyzed cross coupling reactions.Reference of 322-46-3