title: Amino-functionalized pillar[5]arene.
abstract: The recently introduced pillar[n]arenes have provided chemists with receptors that, when incorporated into materials, confer unique properties upon them. The symmetrical rims and cylindrical shape of pillar[5]arene begs the question--can these pillar-like receptors be linked covalently end-to-end in order to create tubular structures by a growth-from-template approach? In our efforts to produce these one-dimensional extended structures, we have developed a new method of functionalizing pillar[5]arene in which one of the five hydroquinone units is converted into a diaminobenzoquinone analogue. The resulting diaminopillar[5]arene derivative, which undergoes a stereochemical inversion process that is slow on the (1)H NMR timescale, can be chemically modified yet further in a direction that is orthogonal to the plane of its methylene bridging carbons through the formation of oxazole heterocycles. This strategy has been employed to create rigid oligomers that resemble one-dimensional tubular arrays. As a proof-of-principle, a rigid pillar[5]arene dimer has been isolated and characterized in the solution state as a 1:1 complex with an extended viologen for which it acts as a receptor.
authors: Center for the Chemistry of Integrated Systems and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208-3113 (USA), Fax: (+1) 847-491-1009.
authors: Nathan L
authors: NL
authors: Strutt
authors: Huacheng
authors: H
authors: Zhang
authors: Severin T
authors: ST
authors: Schneebeli
authors: J Fraser
authors: JF
authors: Stoddart
keywords: host-guest systems; macrocycles; nanostructures; oxazoles; supramolecular chemistry