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Published on: April 19, 2019
Endo-complexation of alkylammonium ions by calix[4]arene cavity: facilitating cation-π interactions through the
Carmen Talotta1, Carmine Gaeta, Placido Neri
1Dipartimento di Chimica e Biologia, Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano, Salerno, Italy.
Abstract:
Notwithstanding its small dimensions, the narrow cavity of p-tert-butylcalix[4]arene macrocycle is still able to host alkylammonium guests in the presence of the tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (TFPB(-)) weakly coordinating (or "superweak") anion. As an artificial analogue of biological receptors, cone-shaped calix[4]arene 1d is able to recognize a n-BuNH3(+) guest mainly through a 4-fold cation-π interaction aided by a weak H-bonding interaction. This recognition motif can be used to assembly a 2:1 capsular architecture with a linear diammonium axle.
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