pH-responsive molecular assemblies of pyridylbutadiene derivative with cucurbit[7]uril

Abstract

The interaction between red-emitting pyridinium derivative [4-((1E,3E)-4-(4-(dimethylamino)phenyl)buta-1,3-dien-1-yl)-1-methylpyridin-1-ium] (DABP) and cucurbit [7]uril was investigated using optical absorption, steady-state and time-resolved fluorescence and anisotropy measurements. The changes in the UV/Vis absorption, fluorescence spectral characteristics and lifetime, with a change in pH, reveal efficient binding of CB7 to the dye molecule. The cucurbit [7]uril encapsulated DABP brings $1.5 units upward pK a shift. The formation of supramolecular assemblies with 1 : 1 and 2 : 1 host-guest stoichiometries with CB7 at different pH conditions have been verified from 1 H NMR, isothermal titration calorimetric studies and geometry optimization calculations. CB7-dye complexation and the ensuing morphological changes were revealed by SEM, AFM and optical microscopy images. This pH-responsive supramolecular assemblies of red-emitting DABP dye can find potential applications in biological imaging, optical pH-sensor and the construction of building blocks for the supramolecular architectures.

Innovative Microstructural Transformation upon CO2 Supercritical Conditions on Metal-Nucleobase Aerogel and Its Use as Effective Filler for HPLC Biomolecules Separation

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Host–guest complexation of APP+ with cucurbit[7]uril. Theoretical and experimental studies on the supramolecular inhibition of its cytotoxicity on SERT

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