Molecular spectra of oxaziridines and diaziridines

Simple oxaziridines and diaziridines do not absorb in the near UV. Lack of absorption was one argument to distinguish between true three-membered ring structures and unsaturated open chain isomers like nitrones or hydrazones. 

An investigation of acylaziridines was carried out by comparison of IR, NMR and MS data and included some 1,2-dibenzoylaziridines as well as 2-p-nitrobenzoyl-3-phenyl-oxaziridine (68IZV1530). Amide conjugation in acylated nitrogen-containing three-membered rings is weaker than in open chain acid amides. 

The IR spectra of oxaziridines often show a band between 1430 and 1470 cm , which is assumed to be due to C—H bending (57JA5739). 

IR spectra of diaziridinones show carbonyl absorption at relatively high wave numbers, as found for aziridinones and cyclopropanones, absorbing at 1855-1880 cm (69JOC2254). 

Vibrational spectra including Raman data of 3,3-dimethyldiaziridine and its hexadeutero compound were recorded in the gas phase and in the crystalline state. Assuming C2 symmetry and employing isotopic shifts and comparison with azetidine, a classification of bands which regarded 33 normal modes could be given (75SA(A)1509). 

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