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

Siva Krishna Mohan Nalluri, Jelle B Bultema, Egbert J Boekema, Bart Jan Ravoo

Research output: Contribution to journalArticle

15 Citations (Scopus)

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.
LanguageEnglish
Pages10297-10303
Number of pages7
JournalChemistry - A European Journal
Volume17
Issue number37
Early online date1 Aug 2011
DOIs
Publication statusPublished - 5 Sep 2011

Fingerprint

Molecular recognition
Adhesion
Agglomeration
Irradiation
Density (optical)
Calorimetry
Dynamic light scattering
Titration
Cryogenics
Transmission electron microscopy
azobenzene

Keywords

  • beta-cyclodextrins
  • molecular structure
  • alpha-cyclodextrins
  • stereoisomerism
  • photochemical processes
  • water
  • azo compounds

Cite this

Nalluri, Siva Krishna Mohan ; Bultema, Jelle B ; Boekema, Egbert J ; Ravoo, Bart Jan. / Photoresponsive molecular recognition and adhesion of vesicles in a competitive ternary supramolecular system. In: Chemistry - A European Journal . 2011 ; Vol. 17, No. 37. pp. 10297-10303.
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Photoresponsive molecular recognition and adhesion of vesicles in a competitive ternary supramolecular system. / Nalluri, Siva Krishna Mohan; Bultema, Jelle B; Boekema, Egbert J; Ravoo, Bart Jan.

In: Chemistry - A European Journal , Vol. 17, No. 37, 05.09.2011, p. 10297-10303.

Research output: Contribution to journalArticle

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AU - Nalluri, Siva Krishna Mohan

AU - Bultema, Jelle B

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N1 - Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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KW - beta-cyclodextrins

KW - molecular structure

KW - alpha-cyclodextrins

KW - stereoisomerism

KW - photochemical processes

KW - water

KW - azo compounds

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