NMR studies of the reversible dimerization and guest exchange processes of tetra urea calix[4]arenes using a derivative with lower symmetry

Article abstract of DOI:10.1021/ja970078o

The calix[4]arene derivative 3 substituted at the wider rim by four urea residues was prepared in three steps from the corresponding tert-butyl calix[4]arene 2a. Due to the different ether residues attached to the narrow rim its constitution is C(2v)-symm