Abstract
The incorporation of proton ionizable moieties, such as 1H-1,2,4-triazole rings, within cyclophanes and π-donor/π-acceptor [2]catenanes is explored as a tool of inducing chemical switchability through either the inherent prototropic tautomerism or chemical deprotonation. Bearing this in mind, in this paper we describe the template-directed synthesis of two tetracationic cyclophanes incorporating two bipyridinium units linked by either one 3,5-bis(methylene)-1H-1,2,4-triazole unit and a p-xylyl unit or two 3,5-bis(methylene)-1H-1,2,4-triazole units, as well as the template-directed synthesis of two [2]catenanes wherein these π-acceptor cyclophanes are interlocked with (bis-p-phenylene-34-crown-10), as the π-electron rich polyether macrocycle. We also report on the full characterization of the cyclophanes and the [2]catenanes by electrospray mass spectrometry (ESMS) and fast atom bombardment mass spectrometry (FABMS), X-ray crystallography of the [2]catenanes and dynamic 1H NMR spectroscopy. We reveal that the [2]catenane incorporating one triazole ring in the tetracationic cyclophane exists, in the solid-state, as hydrogen bond cross-linked enantiomeric pair stacks, whereas the [2]catenane incorporating two triazole rings in the tetracationic cyclophane does not form polar stacks, unlike most of the [2]catenanes of this class. Finally, we studied the chemical stability of these π-donor/π-acceptor motifs to explore their chemical switchability, to show the triazolate-bipyridinium pair is a challenging one in this sense.
Original language | English (US) |
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Pages (from-to) | 300-317 |
Number of pages | 18 |
Journal | New Journal of Chemistry |
Volume | 33 |
Issue number | 2 |
DOIs | |
State | Published - 2009 |
ASJC Scopus subject areas
- Catalysis
- General Chemistry
- Materials Chemistry
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CCDC 708197: Experimental Crystal Structure Determination
Ramos, S. (Creator), Alcalde, E. (Creator), Fraser, S. J. (Contributor), White, A. J. P. (Creator), Williams, D. J. (Creator) & Pérez-García, L. (Contributor), Cambridge Crystallographic Data Centre, 2009
DOI: 10.5517/ccrry2h, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccrry2h&sid=DataCite
Dataset
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CCDC 708196: Experimental Crystal Structure Determination
Ramos, S. (Creator), Alcalde, E. (Creator), Fraser, S. J. (Contributor), White, A. J. P. (Creator), Williams, D. J. (Creator) & Pérez-García, L. (Contributor), Cambridge Crystallographic Data Centre, 2009
DOI: 10.5517/ccrry1g, http://www.ccdc.cam.ac.uk/services/structure_request?id=doi:10.5517/ccrry1g&sid=DataCite
Dataset