Second generation calix[6]trenamides-Highly selective graftable receptors for neutral guests and contact ion pairs

摘要

With the aim of designing graftable calix[6]tren-based receptors, calix[6]trenamides decorated with an appended functional arm were synthesized through [1+1] macrocyclization reactions between calix[6]trisamines and NTA-lysine derivatives. NMR spectroscopy and ESI-MS studies showed that one of these calix[6]trenamides, 5, behaves as a unique heteroditopic receptor towards charged or neutral species. Notably, it can selectively bind contact ammonium fluoride salts through a highly cooperative process. In addition, acid-base control of its binding properties was clearly evidenced. This second generation of graftable receptors opens new perspectives in the design of sensors for charged or neutral species.