Knowledge Bank

The microwave spectrum of ethylene glycol clearly shows effects due to the internal rotation of the two hydrogen bonds. Rapid exchange between equivalent conformations is possible through simultaneous internal rotation of the hydroxyl groups. Low J $\mu a$. R-branch transitions have been identified for $CH2OD-CH2OD$ by mw-mw double resonance measurements. The deuterated molecule was investigated primarily because its internal rotation splittings are much smaller than those in the unlabeled species. All transitions appear as doublets with almost constant splitting. The centers follow a rigid rotor pattern.