Supramolecular Complexation of Azobenzene Dyes by Cucurbit[7]uril.

ABSTRACT: This report describes cucurbit[7]uril (CB7) complexation of azobenzene dyes that have a 4-(N,N'-dimethylamino) or 4-amino substituent. Absorption and NMR data show that CB7 encapsulates the protonated form of the azobenzene and that the complexed dye exists as its azonium tautomer with a trans azo conformation and substantial quinoid resonance character. Because CB7 complexation stabilizes the dye conjugate acid, there is an upward shift in its pK_a, and in one specific case, the pK_a of the protonated azobenzene is increased from 3.09 to 4.47. Molecular modeling indicates that the CB7/azobenzene complex is stabilized by three major noncovalent factors: (i) ion-dipole interactions between the partially cationic 4-(N,N'-di

SUBMITTER: Kommidi SSR 

PROVIDER: S-EPMC10843849 | biostudies-literature | 2023 Jul

REPOSITORIES: biostudies-literature