Thermal gravimetry, mass spectrometry and solid-state 13C NMR spectroscopy—simple and efficient methods to characterize the inclusion behaviour of p-tert-butylcalix[n]arenes

Abstract

The solid state inclusion of various organic solvent molecules in p-tert-butylcalix[4]arene and p-tert-butylcalix[6]arene has been studied by thermal gravimetry and electron impact mass spectrometry (EI-MS). The host–guest ratio varies from 1∶2 to 4∶1 and the nature of included guest has been determined by EI-MS. Thermal gravimetric analysis of solvent–p-tert-butylcalix[n]arene complexes gives a qualitative order of intramolecular forces involved. Structural information obtained by cross-polarization magic angle spinning (CP-MAS) ¹³C NMR spectroscopy is in good agreement with known data from single-crystal X-ray diffraction analysis.