Vibrational spectra and molecular mechanics and ab initio calculations for 1,3-dioxole. Confirmation of non-planarity

Abstract

Infrared and Raman spectra of the vapor, liquid, and solid phases of 1,3-dioxole have been recorded and analyzed. Much of the spectra can be interpreted assuming C 2v symmetry. However, several combination bands with the ring-puckering vibration along with the observation of an otherwise inactive mode confirm the non-planarity of this molecule. The observed frequencies are compared with predicted values from molecular mechanics (MM3) and ab initio (STO3-21G∗) calculations. These calculated values provide useful estimates but about half of them differ from the observed values by more than 50 cm −1. Several predicted values disagree by more than 200 cm −1.