Relationships between torsional angles and ring-puckering coordinates Part IV.Application to four-membered rings

Modular chemical geometry and symbolic calculation

“…These include the determination of the puckering or planarity of many 4‐atom ring compounds from experimental data. Recent work includes x‐ray crystallography of trimethylene imine, oxetane, and thietane by Esteban et al 30 and in many studies of silaheterocycles by Weidenbruch, e.g., Ref. 31 Nuclear magnetic resonance (NMR) of caryophyllenes by Clericuzlo et al 32 and trimethylene imine in relation to its polymers 33 Electron diffraction of 1,1Me 2 silaCB by Novikov et al 34 Infrared (IR) spectra of 1,1F 2 CB by Lesarri et al 35, oxetane by Moruzzi et al 36, thietane and seletane by Pousa et al 37, and complexes of oxetane and thietane with HCl by Rode and Dobrowolski 38 Raman spectra in Ref.…”

“…x‐ray crystallography of trimethylene imine, oxetane, and thietane by Esteban et al 30 and in many studies of silaheterocycles by Weidenbruch, e.g., Ref. 31…”

“…41. Coupling between ring puckering and methylene rocking is considered in Refs. 30, 44, 50. The puckering of the CB ring in thymine dimers is important in a photofragmentation that serves as a model process for the reactivation of pyrimidine dimer in the repair of toxic and mutagenic effects of far ultraviolet (UV) irradiation of DNA 42. “A correct description of the CB ring puckering is indispensable to predict minimum energy geometry of … sesquiterpenes of common and widespread occurrence in nature” 32. The puckering of the heavily halogenated CBs computed in Ref. 48 is relevant to the action of related anesthetics.…”