Inconvertible p-tert-butylthiacalix[4]arene-core-star polystyrene conformers

Abstract

Inconvertible p-tert-butylthiacalix[4]arene-core-star-shaped polystyrene conformers were synthesized by atom transfer radical polymerization (ATRP) using initiators of different conformations from p-tert-butylthiacalix[4]arene. ¹H NMR and selective 1D NOESY analyses confirmed that the spatial structures of the initiator cores in the 4-arm star polymers were preserved during the polymerization process. While size exclusion chromatography (SEC) analyses revealed a diminishing difference in the hydrodynamic volume of the star polymer conformers as the molar mass increases, reversed phase liquid chromatography distinguishes the 4-arm star polymer having a cone-shaped core from the polymer having a 1,3-alternate-shaped core likely due to their isomeric locations of the hydrophobic tBu groups of the core. This result demonstrates that the inconvertible conformational structures of star polymers having the same composition exhibit distinguishable properties.