Crystal structure of p-chloro-N-benzylhexahomotriazacalix[3]arene and of the complex of its zwitterionic form with neodymium(III) nitrate

摘要

p-Chloro-N-benzylhexahomotriazacalix[3]arene reacts with neodymium(III) nitrate to form a 1:1 complex in which the cation is bound to the three phenoxide oxygen atoms and to three bidentate nitrate ions. In the uncomplexed ligand, the three phenolic oxygen atoms form hydrogen bonds with the nitrogen atoms, whereas, in the complexed form, the three amine groups are transformed into ammonium cations by intramolecular transfer of protons (zwitterionic form) and form hydrogen bonds with the complexed phenoxide groups. The formation of this complex is peculiar among other lanthanide complexes of calixarenes since it occurs without addition of a basic agent, other than the amine groups included in the ligand molecule itself. [References: 36]