Chiral explosives: A theoretical investigation of structure and chiroptical properties of triacetone triperoxide and hexamethylene triperoxide diamine.

Triacetone triperoxide (TATP) and hexamethylene triperoxide diamine (HMTD) are cyclic peroxides that exhibit atropisomerism resulting from restricted rotation around three peroxide bonds. As a result, one pair of enantiomers with D symmetry and another pair of enantiomers with C symmetry can be identified. Previous studies, based on mass spectrometry data and computational results, have shown that conformations of TATP with D and C symmetry can be isolated. Assuming that enantiomer samples of TATP and HMTD can be obtained with sufficient enantiopurity, we investigated their chiroptical properties, namely, optical rotatory dispersion (ORD), vibrational circular dichroism (VCD), and Raman optical activity (VROA). ORD curves and VCD spectra are seen to be very similar for D - and C -symmetric atropisomers with the same overall helicity. Predicted VROA results, however, show significant differences between D - and C -symmetric atropisomers with the same overall helicity. The D -symmetric atropisomer is predicted to exhibit considerably larger magnitude vibrational optical activity signals than the C -symmetric atropisomer.