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Breaking Aggregation and Driving the Keto-to-gem-Diol Equilibrium of the N,N'-Dimethyl-2,6-diaza-9,10-anthraquinonediium Dication to the Keto Form by Intercalation in Cucurbit[7]uril
Journal of Organic Chemistry
  • Arumugam Thangavel
  • Ian A. Elder
  • Lia Sotiriou-Leventis, Missouri University of Science and Technology
  • Richard Dawes, Missouri University of Science and Technology
  • Nicholas Leventis, Missouri University of Science and Technology
Abstract
1H NMR, ESI-MS, and DFT calculations with the M062X/6-31G* method show that, in water, the bistetrafluoroborate salt of N,N'-dimethyl-2,6-diaza-9,10-anthraquinonediium dication (DAAQ·2BF4-) exists in equilibrium with both its gem-diol and several aggregates (from dimers to at least octamers). with high concentrations of HCl (e.g., 1.2–1.5 M), all aggregates break up and the keto-to-gem-diol equilibrium is shifted quantitatively toward the quinone form. the same effect is observed with 1.5 mol equiv of cucurbit[7]uril, CB[7], with which all equilibria are shifted toward the quinone form, which undergoes slow exchange with the CB[7] cavity as both the free and the CB[7]-intercalated quinone (DAAQ@CB[7]) are observed simultaneously by 1H NMR. the affinity of DAAQ for the CB[7] cavity (Keq = 4 × 106 M–1) is in the range found for tricyclic dyes (0.4–5.4 × 106 M–1), and among the highest observed to date. a computational comparative study of the corresponding CB[7] complex of the N,N'-dimethyl-4,4'-bipyridinium dication (N,N'-dimethyl viologen, MeV) suggests that the higher binding constant for intercalation of DAAQ may be partially attributed to a lesser distortion of CB[7] (required to maximize favorable nonbonding interactions) as a result of the flat geometry of DAAQ.
Department(s)
Chemistry
Keywords and Phrases
  • Binding constant,
  • Bipyridinium,
  • Comparative studies,
  • Cucurbit[7]uril,
  • DFT calculation,
  • Dications,
  • Non-bonding interactions,
  • Viologens, Aggregates,
  • Computational geometry, Polyols, 4,4' bipyridine,
  • anthraquinone derivative,
  • cucurbit[7]uril,
  • dimer,
  • dye,
  • heterocyclic compound,
  • hydrochloric acid,
  • ketone derivative,
  • unclassified drug, article,
  • binding affinity,
  • comparative study,
  • crystal structure,
  • density functional theory,
  • electrospray mass spectrometry,
  • intercalation complex,
  • mathematical computing,
  • molecular interaction,
  • proton nuclear magnetic resonance,
  • reaction analysis, Alcohols,
  • Bridged Compounds,
  • Cations,
  • Crystallography, X-Ray,
  • Imidazoles,
  • Isoquinolines,
  • Ketones,
  • Models, Molecular,
  • Molecular Structure,
  • Quantum Theory,
  • Quinones
Document Type
Article - Journal
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2013 American Chemical Society (ACS), All rights reserved.
Publication Date
9-1-2013
Disciplines
Citation Information
Arumugam Thangavel, Ian A. Elder, Lia Sotiriou-Leventis, Richard Dawes, et al.. "Breaking Aggregation and Driving the Keto-to-gem-Diol Equilibrium of the N,N'-Dimethyl-2,6-diaza-9,10-anthraquinonediium Dication to the Keto Form by Intercalation in Cucurbit[7]uril" Journal of Organic Chemistry Vol. 78 Iss. 17 (2013) p. 8297 - 8304 ISSN: 0022-3263
Available at: http://works.bepress.com/richard_dawes/43/