CONFORMATIONAL-ANALYSIS OF POLY(ETHYLENE OXIDE) OLIGOMERS - DIGLYME

The changes in energy of the diethylene oxide dimethylether H3C(OCH2CH 2)2OCH3, oligomer of poly(ethylene oxide), as a function of rotation a round C-C and C-0 bonds have been analyzed by ab initio calculations. For the highest level calculations, MP2/6-31 + + G*//HF/3-21 G a gauc he conformation around a C-C bond is nearly equal in energy with the a ll trans conformer. The torsional potentials for the C-C and C-0 bonds are presented. The activation energy for the chain motion of a crysta lline poly(ethylene oxide) derived from the NMR experiments is 28 kJ/m ol. This implies that rotation around more than one bond must be invol ved in the associated conformational change.