TY - JOUR AU - Humeniuk, H.V. AU - Licari, G. AU - Vauthey, E. AU - Sakai, N. AU - Matile, S. TI - Mechanosensitive membrane probes: push-pull papillons PY - 2020 JF - Supramol. Chem. JA - Supramol. Chem. VL - 32 SP - 106 EP - 111 L1 - https://www.tandfonline.com/doi/pdf/10.1080/10610278.2019.1702193?needAccess=true L2 - https://www.tandfonline.com/doi/full/10.1080/10610278.2019.1702193 L3 - https://www.tandfonline.com/doi/full/10.1080/10610278.2019.1702193 M3 - 10.1080/10610278.2019.1702193 UR - http://dx.doi.org/10.1080/10610278.2019.1702193 N2 - 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%). ID - 1648 ER -