Evidence of a host:guest complex between p-t-butylcalix[4] arene and carbon dioxide

In this paper we report evidence for an inclusion complex between carbon dioxide and p-t-butylcalix[4] arene. The complex was studied with infrared spectroscopy, single-crystal X-ray diffraction, solid-state NMR, and thermogravimetric analysis. Results indicate that 70% of the p-t-butylcalix[ 4] arene cavities could be occupied by a CO2 molecule following exposure at 30 MPa and 40degreesC.