Takudrei

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The synergetic interplay of weak interactions in the ion pair recognition of quaternary and diquaternary ammonium salts by halogenated resorcinarenes

N. K. Beyeh, M. Göth, L. Kaufmann, C.A. Schalley, K. Rissanen— 2013

The influence of halogens on the non-covalent interactions of different upper-rim-substituted hexyl resorcinarenes with quaternary and diquaternary ammonium iodide salts were investigated in the gas phase by electrospray ionization Fourier-transform ion-cyclotron-resonance (ESI-FTICR) mass spectrometry and in solution by 1H NMR titrations studies. The electronic nature of the substituents on the upper rim of the resorcinarene is directly reflected in the order of binding strengths of the hosts towards the quaternary and diquaternary ammonium cations in the gas phase. In solution, the opposite trend of increasing binding constants with increasing electronegativity of the halogens was observed with generally higher binding constants for the diquaternary over the quaternary salts. This phenomenon is explained by the synergetic effect originating from the interaction of the halogenated resorcinarenes with the counter anions through enhanced hydrogen bonding leading to ion pair binding in solution. The electronegativity of the halogens renders the hydrogen of the hydroxyl group more acidic and hence enhances hydrogen bonding in solution. The collective effect of several weak interactions is manifested in solution thereby emphasizing the benefits of comparing solution and gas phase studies in recognition processes.

Title190
The synergetic interplay of weak interactions in the ion pair recognition of quaternary and diquaternary ammonium salts by halogenated resorcinarenes
AuthorN. K. Beyeh, M. Göth, L. Kaufmann, C.A. Schalley, K. Rissanen
Date20131021
IdentifierDOI 10.1002/ejoc.201300886
Source(s)
CitationEur. J. Org. Chem. 2014, 80-85