title: Arylazopyrazoles as Light-Responsive Molecular Switches in Cyclodextrin-Based Supramolecular Systems.
abstract: A simple and high yield synthesis of water-soluble arylazopyrazoles (AAPs) featuring superior photophysical properties is reported. The introduction of a carboxylic acid allows the diverse functionalization of AAPs. Based on structural modifications of the switching unit the photophysical properties of the AAPs could be tuned to obtain molecular switches with favorable photostationary states. Furthermore, AAPs form stable and light-responsive host-guest complexes with β-cyclodextrin (β-CD). Our most efficient AAP shows binding affinities comparable to azobenzenes, but more effective switching and higher thermal stability of the Z-isomer. As a proof-of-principle, we investigated two CD-based supramolecular systems, containing either cyclodextrin vesicles (CDVs) or cyclodextrin-functionalized gold nanoparticles (CDAuNPs), which revealed excellent reversible, light-responsive aggregation and dispersion behavior. To conclude, AAPs have great potential to be incorporated as molecular switches in highly demanding and multivalent photoresponsive systems.
authors.affiliation: Organic Chemistry Institute and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany.
authors.forename: Lucas
authors.initials: L
authors.lastname: Stricker
authors.affiliation: Organic Chemistry Institute and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany.
authors.forename: Eva-Corinna
authors.initials: EC
authors.lastname: Fritz
authors.affiliation: Institute of Materials Physics, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Peterlechner
authors.affiliation: Institute for Solid State Theory and Center for Multiscale Theory & Computation, Westfälische Wilhelms-Universität Münster , Wilhelm-Klemm-Str. 10, 48149 Münster, Germany.
authors.forename: Nikos L
authors.initials: NL
authors.lastname: Doltsinis
authors.affiliation: Organic Chemistry Institute and Center for Soft Nanoscience, Westfälische Wilhelms-Universität Münster , Corrensstrasse 40, 48149 Münster, Germany.
authors.forename: Bart Jan
authors.initials: BJ
authors.lastname: Ravoo