Vibrational spectra and potential energy distributions of normal modes of 3-nitroso- and 3-nitrocyclopropenes

Abstract

The structural stability of 3-nitrosocyclopropene c-C 3H 3–NO and 3-nitrocyclopropene c-C 3H 3–NO 2 was investigated by density functional B3LYP and ab initio MP2 calculations using 6-311+G ∗∗ basis set. From the calculation, 3-nitrosocyclopropene was predicted to exist predominantly in the trans conformation (NO bond is trans to the ring and eclipse α-hydrogen of the ring) with high trans– cis rotational barrier of about 8 kcal/mol. The NO 2 rotational barrier in 3-nitrocyclopropene was predicted from the symmetric potential scan to be of about 4.4 kcal/mol. The vibrational frequencies were computed at DFT-B3LYP/6-311+G ∗∗ level for both molecules. Normal coordinate calculations were carried out and potential energy distributions were calculated for the two molecules.