Affiliation:
1. Department of Chemistry Faculty of Technology Tomas Bata University in Zlín Vavrečkova 5669 760 01 Zlín Czech Republic
2. Institut für Chemie und Biochemie Freie Universität Berlin Arnimallee 20 14195 Berlin Germany
3. Department of Environmental Protection Engineering Faculty of Technology Tomas Bata University in Zlín, Nad Ovčírnou 3685 760 01 Zlín Czech Republic
4. Department of Chemistry Faculty of Science Masaryk University Kotlářská 2 602 00 Brno Czech Republic
Abstract
AbstractRedox–active components are highly valuable in the construction of molecular devices. We combined two p‐phenylenediamines (p‐PDA) with a biphenyl (BiPhe) unit to prepare a supramolecular guest 4 consisting of three binding sites for cucurbit[7/8]uril (CBn) and/or cyclodextrins (CD). Supramolecular properties of 4 were investigated using NMR, UV‐vis, mass spectrometry and isothermal titration calorimetry. Our analysis revealed that 4 forms higher–order host–guest complexes, wherein a CD unit occupies the central BiPhe site, secured by two CBn units at the terminal p‐PDA sites. Additionally, 1 : 1 complexes with α‐CD and β‐CD, a 1 : 2 complex with γ‐CD and 2 : 1 complexes with CB7 and CB8 were identified. Through UV‐vis and cyclic voltammetry, redox processes leading to the formation of a stable, deep blue dication diradical of 4 are elucidated. Furthermore, it is demonstrated that CB7 selectively protects oxidised 4 from reduction in the presence of a reducing agent. The supramolecular and redox properties of the structural motif represented by 4 render it an interesting candidate for the construction of supramolecular devices.
Funder
Univerzita Tomáše Bati ve Zlíně
Ministerstvo Školství, Mládeže a Tělovýchovy