[2]pseudorotaxanes derived from 27-and 29-membered oxaazacyclophanes and 1,2-bis(benzimidazolium)ethane salts

Viviana Reyes-Márquez, Jorge Tiburcio, Herbert Höpfl, Mario Sanchez-Vazquez, Iran F. Hernández-Ahuactzi, Ramón Moreno-Corral, Karen O. Lara

Research output: Contribution to conferencePaperpeer-review

3 Scopus citations


Four novel 27- and 29-membered oxaazacyclophanes were synthetized via the high dilution method in moderate to good yields, employing aromatic dialdehydes and diamines as precursors to generate first the corresponding cyclic Schiff bases, which were then reduced in almost quantitatively yields to the corresponding macrocyclic diamines. All compounds were characterized by conventional techniques such as IR and NMR (1H, 13C) spectroscopy, elemental analysis, and mass spectrometry. Besides, two macrocycles were studied by single-crystal X-ray diffraction analysis, which revealed that their cavities are appropriate to include small molecules. Using two representative oxaazacyclophanes (OX-3 and OX-4) as wheels and 1,2-bis(benzimidazolium)ethane salts as axles, [2]pseudorotaxanes were formed in 1:1 (v/v) solvent mixtures of CHCl3 and MeCN and studied by 1H NMR and ultraviolet/visible (UV/Vis) spectroscopy, and electrospray ionization-time-of-flight mass spectrometry, finding in all cases the formation of stable 1:1 complexes. The binding constants of the complexes were determined by UV/Vis and 1H NMR titration experiments, giving values ranging from 0.52×103 to 4.6×103M-1. Likely, complex structures were investigated in the gas-phase using density functional theory calculations at the B3LYP/6-31G(d) level of theory. The complexation experiments together with the results from the molecular modeling studies indicate that dicationic axles can penetrate the cavity of the oxaazacyclophanes synthesized herein to give a new family of [2]pseudorotaxanes. These supramolecular structures are held together by φ-φ stacking interactions (charge-transfer), charge-assisted hydrogen bonds, and ion dipole forces. Copyright © 2012 John Wiley & Sons, Ltd.
Original languageAmerican English
Number of pages11
StatePublished - 1 Nov 2012
EventJournal of Physical Organic Chemistry -
Duration: 1 Nov 2012 → …


ConferenceJournal of Physical Organic Chemistry
Period1/11/12 → …


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