The puckering coordinate in oxetane

Abstract

The recently determined a _pucker ^(xz) = ∂I_xz /∂Q _pucker constants for five isotopic species of oxetane have been interpreted quantitatively by allowing the ring-puckering normal coordinate to contain a small amount of methylene rocking and twisting motion. The observed data are most closely reproduced by assuming a methylene rock angle of about 3° and a twist angle for the α-methylene groups of about 1° at the equilibrium conformation of the ring.