Lower rim dimerization of a calixarene through the encapsulation of sodium ions

Here we report the tail-to-tail dimerization of tetra(carboxymethoxy)calix[4]arene in both solution and solid state phases using ESI-orbitrap UHRMS, 1 H-NMR and single-crystal X-ray diffraction techniques. Three sodium ions are encapsulated into the dimeric structure which is also stabilized by hydrogen bonds between carboxyl moieties undergoing partial deprotonation. Here we report the tail-to-tail dimerization of tetra(carboxymethoxy)calix[4]arene in both solution and solid state phases.