Vibrational spectra and conformational isomerism of calixarene building blocks. II. Bis(2-hydroxyphenyl)methane

The conformations and vibrational spectra of bis(2-hydroxyphenyl)methane have been analysed within the framework of density functional theory. The calculated force fields (B3LYP/6-31G*) of seven possible energy minima were transformed to internal coordinates, and a set of ten different scaling factors was applied. The scaled quantum mechanical (SQM) method reproduces the experimental IR and Raman spectra with high accuracy. The dependence of the CH2 stretching vibrations on the conformation and the possibility of its use as a probe for larger systems, e.g., calixarenes or polyphenols, are discussed.