Jump to main content
Jump to site search

Issue 10, 2018
Previous Article Next Article

Protonation-induced ultrafast torsional dynamics in 9-anthrylbenzimidazole: a pH activated molecular rotor

Author affiliations

Abstract

We report the photophysical properties and excited state dynamics of 9-anthrylbenzimidazole (ANBI) which exhibits protonation-induced molecular rotor properties. In contrast to the highly emissive behavior of neutral ANBI, protonation of the benzimidazole group of ANBI induces efficient nonradiative deactivation by ultrafast torsional motion around the bond connecting the anthracene and benzimidazole units, as revealed by ultrafast transient absorption and fluorescence spectroscopy. Contrary to viscosity-independent fluorescence of neutral dyes, protonated ANBI is shown to display linear variation of emission yield and lifetime with solvent viscosity. The protonation-induced molecular rotor properties in the studied system are shown to be driven by enhanced charge transfer and are corroborated by quantum chemical calculations. Potential application as a microviscosity sensor of acidic regions in a heterogeneous environment by these proton-activated molecular rotor properties of ANBI is discussed.

Graphical abstract: Protonation-induced ultrafast torsional dynamics in 9-anthrylbenzimidazole: a pH activated molecular rotor

Back to tab navigation

Supplementary files

Publication details

The article was received on 15 Dec 2017, accepted on 01 Feb 2018 and first published on 02 Feb 2018


Article type: Paper
DOI: 10.1039/C7CP08408K
Citation: Phys. Chem. Chem. Phys., 2018,20, 7014-7020
  •   Request permissions

    Protonation-induced ultrafast torsional dynamics in 9-anthrylbenzimidazole: a pH activated molecular rotor

    A. Nandi, A. Kushwaha, D. Das and R. Ghosh, Phys. Chem. Chem. Phys., 2018, 20, 7014
    DOI: 10.1039/C7CP08408K

Search articles by author

Spotlight

Advertisements