Knowledge Bank

The infrared (4000 --- $30cm-1$) and Raman spectra of carbonylbis (1-aziridine), sulfinylbis (1-aziridine) and 1-aziridinyl carboxamide have been recorded. A complete assignment of the normal vibrations of carbonylbis (1-aziridine) has been based on Raman polarizations and analogies to ethylenimine and urea. A partial normal coordinate analysis was carried out to substantiate the assignments of the skeletal vibrations. The results indicated considerable mixing of several of the low frequency modes. The approximate barrier to internal rotation of the aziridine ring in this molecule has been calculated from the observed torsional frequency. The fundamental vibrations of sulfinylbis (1-aziridine) and 1-aziridinyl carboxamide have been assigned by comparisons with carbonylbis (1-aziridine). The absorptions arising from the sulfoxide group in sulfinylbis (1-aziridine) were identified from frequency shifts produced by intermolecular association of the sulfoxide linkage with chloroform. The vibrational modes of the $NH2$ group in 1-aziridinyl carboxamide were assigned on the basis of the observed shifts of the corresponding absorptions in the spectrum of 1-aziridinyl carboxamide-$d2$.