Photoresponsive molecular recognition and adhesion of vesicles in a competitive ternary supramolecular system

Nalluri, Siva Krishna Mohan and Bultema, Jelle B and Boekema, Egbert J and Ravoo, Bart Jan (2011) Photoresponsive molecular recognition and adhesion of vesicles in a competitive ternary supramolecular system. Chemistry - A European Journal, 17 (37). pp. 10297-10303. ISSN 0947-6539 (https://doi.org/10.1002/chem.201100789)

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Abstract

A competitive photoresponsive supramolecular system is formed in a dilute aqueous solution of three components: vesicles of amphiphilic α-cyclodextrin host 1a, divalent p-methylphenyl guest 2 or divalent p-methylbenzamide guest 3, and photoresponsive azobenzene monovalent guest 5. Guests 2 and 3 form weak inclusion complexes with 1a (K(a)≈10(2) M(-1)), whereas azobenzene guest 5 forms a strong inclusion complex (K(a)≈10(4) M(-1)), provided it is in the trans state. The aggregation and adhesion of vesicles of host 1a is mediated by guest 2 (or 3) due to the formation of multiple intervesicular noncovalent links, as confirmed by using isothermal titration calorimetry (ITC), optical density measurements at 600 nm (OD600), dynamic light scattering (DLS), and cryogenic transmission electron microscopy (cryo-TEM). The addition of excess monovalent guest trans-5 to vesicles of 1a aggregated by divalent guest 2 (or 3) causes the dispersion of vesicles of 1a because trans-5 displaces 2 (as well as 3) from the vesicle surface. Upon UV irradiation of a dilute ternary mixture of vesicles of 1a, guest 2 (or 3), and competitor trans-5, compound trans-5 isomerizes to cis-5, and renewed aggregation of vesicles of 1a by guest 2 (or 3) occurs because 2 (as well as 3) displaces cis-5 from the vesicle surface. Subsequent visible irradiation causes the redispersion of vesicles of 1a because cis-5 reisomerizes into trans-5, which again displaces guest 2 (or 3) from the vesicle surface. In this way, the competitive photoresponsive aggregation and dispersion of vesicles can be repeated for several cycles.

  • Item type:Article
    ID code:45510
    Dates:
    Date
    Event
    5 September 2011
    Published
    1 August 2011
    Published Online
    Notes:Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Subjects:Science > Chemistry
    Department:Faculty of Science > Pure and Applied Chemistry
    Depositing user: Pure Administrator
    Date deposited:01 Nov 2013 09:45
    Last modified:08 Apr 2024 20:53
    URI:https://strathprints.strath.ac.uk/id/eprint/45510
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