Structures and vibrational spectra for the conformers of CH 3OCH 2CH 2OH

Abstract

The structures of the relevant conformations of 2-methoxyethanol (CH 3OCH 2CH 2OH, abbreviated C 1E 1) are determined by ab initio MO calculations with different basis sets (STO-3G, STO-3G ∗, 3-21G, 3-21G ∗, 4-21G ∗, 6-31G, 6-31G ∗, 6-31G ∗∗, MP2/6-31G ∗//6-31G ∗, MP2/6-31G ∗. Normal coordinate analyses and calculation of vibrational frequencies were performed using the ab initio derived force fields for the 3-21G ∗ and 6-31G ∗ basis sets. A comparison of the performances of the various basis sets is made for the conformational energy differences, the structures of the conformers and the ab initio derived vibrational spectra, leading to the general conclusion that the 3-21G ∗ basis set is the lowest level of calculation which is able to reproduce adequately the conformational energy differences and the changes in the structural parameters for the various conformers as given by the MP2/6-31G ∗ calculations, thus accounting in a reliable way for the interplay between the conformational and intramolecular hydrogen bonding interactions in C 1E 1.