DFT and IR spectroscopic analysis of p-tert-butylthiacalix[4]arene

Vibrational analysis of p-tert-butylthiacalix[4]arene based on an experimental mid and far IR spectra is described here. Density functional calculations of a most stable cone conformer related to crystalline solid FT-IR spectra in the temperature range up to 180 °C as well spectra of dilute solution have been used to obtain a better understanding of conformational state and a hydrogen bonding of p-tert-butylthiacalix[4]arene. Complete assignments were made for experimental FT-IR spectra of the cone conformer. Heating (up to 180 °C) of crystalline p-tert-butylthiacalix[4]arene did not change both conformational and cooperative H-bonding state of its molecules. A temperature spectral effect seems to be due to some relaxation of crystal packing mostly viewed on the OH bands.