MICROWAVE-SPECTRUM, CONFORMATION, INTRAMOLECULAR HYDROGEN-BONDING ANDAB-INITIO CALCULATIONS FOR ETHYLENE-GLYCOL VINYL ETHER

The microwave spectra of ethylene glycol vinyl ether and one deuterate d species (hydroxyl group) have been investigated in the 26.0-39.0 GHz spectral region at -15 degrees C. One rotamer, denoted Conformer I, w as assigned. This rotamer is stabilized by an intramolecular O-H ... O hydrogen bond formed between the hydrogen atom of the hydroxyl group and the oxygen atom of the ether group. The C-C-O-C=C chain of atoms i s practically planar, with the double bond and the O-CH2 bonds in a sy n conformation. The O-CH2-CH2-O link is in a gauche conformation, allo wing the hydrogen bond to be formed. Absolute intensity measurements i ndicate that this rotamer is at least 3 kJ mol(-1) more stable than an y other rotameric form of the molecule. The microwave work has been as sisted by infrared spectra of the gas as well as ab initio computation s made at the MP2/6-31G* lever of theory.