title: Photoresponsive switches at surfaces based on supramolecular functionalization with azobenzene-oligoglycerol conjugates.
abstract: The synthesis, supramolecular complexation, and switching of new bifunctional azobenzene-oligoglycerol conjugates in different environments is reported. Through the formation of host-guest complexes with surface immobilized β-cyclodextrin receptors, the bifunctional switches were coupled to gold surfaces. The isomerization of the amphiphilic azobenzene derivatives was examined in solution, on gold nanoparticles, and on planar gold surfaces. The wettability of functionalized gold surfaces can be reversibly switched under light-illumination with two different wavelengths. Besides the photoisomerization processes and concomitant effects on functionality, the thermal cis to trans isomerization of the conjugates and their complexes was monitored. Thermal half-lives of the cis isomers were calculated for different environments. Surprisingly, the half-lives on gold nanoparticles were significantly smaller compared to planar gold surfaces.
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin (Germany) http://www.polytree.de.
authors.forename: Olaf
authors.initials: O
authors.lastname: Nachtigall
authors.forename: Christian
authors.initials: C
authors.lastname: Kördel
authors.forename: Leonhard H
authors.initials: LH
authors.lastname: Urner
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D005990:Glycerol / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006207:Half-Life; D053768:Metal Nanoparticles; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D001391:Azo Compounds; D047392:beta-Cyclodextrins; D006046:Gold; C009850:azobenzene; C031215:betadex; D005990:Glycerol
keywords: azobenzene; half-life; host-guest chemistry; molecular switches; surface chemistry