Thermal isomerisation of 25,26,27,28-tetrapropoxy-2,8,14,20-tetrathiacalix[4]arene: isolation of all four conformers

Abstract

25,26,27,28-Tetrapropoxy-2,8,14,20-tetrathiacalix[4]arene undergoes a thermal equilibration at elevated temperature yielding a mixture of conformers. The rate and equilibrium constants of this process were established using NMR spectroscopy. For the first time the equilibrating process was also used on a preparative scale for the isolation and characterisation of all four basic thiacalix[4]arene conformations.