Mechanosensitive membrane probes: push-pull papillons. Issue 2 (1st February 2020)

• Record Type: Journal Article
• Authors: Humeniuk, Heorhii V.; Licari, Giuseppe; Vauthey, Eric; Sakai, Naomi; Matile, Stefan
• Is Part Of: Supramolecular chemistry. Volume 32:Issue 2(2020)
• Page Start: 106
• Page End: 111
• Publication Date: 2020-02-01
• Subjects: Mechanochemistry -- bent aromatics -- fluorescent probes -- lipid bilayer membranes -- push–pull systems; Macromolecules -- Periodicals; Supramolecular chemistry -- Periodicals; 547.005
• DOI: 10.1080/10610278.2019.1702193
• Languages: English
• ISSNs: 1061-0278

Abstract

ABSTRACT: Design, synthesis and evaluation of push-pull N, N ′-diphenyl-dihydrodibenzo[a, c]phenazines are reported. Consistent with theoretical predictions, donors and acceptors attached to the bent mechanophore are shown to shift absorption maxima to either red or blue, depending on their positioning in the chromophore. Redshifted excitation of push-pull fluorophores is reflected in redshifted emission of both bent and planar excited states. The intensity ratios of the dual emission in more and less polar solvents imply that excited-state (ES) planarization decelerates with increasing fluorophore macrodipole, presumably due to attraction between the wings of closed papillons. ES planarization of highly polarisable papillons is not observed in lipid bilayer membranes. All push-pull papillon amphiphiles excel with aggregation-induced emission (AIE) from bent ES as micelles in water and mechanosensitivity in viscous solvents. They are not solvatochromic and only weakly fluorescent (QY < 4%). Graphical Abstract: