Thermal Stability and Stereoelectronic Effects on Trifluoromethyl Peroxynitrates: A Combined Experimental and Computational Approach

Abstract

Organic peroxynitrates are important reservoir species in the atmosphere. In this work we examine the correlation between the structural features (geometric parameters and normal vibrational modes) of CF3OONO2, CF3 C(O)OONO2, CF3OC(O)OONO2, and their thermal stabilities. The dissociation energy for the O─N bond, involving in the rupture of molecules was calculated using the Gaussian16 program, with the B3LYP/6–311 + G(2df) method and basis set (103.2, 118.2, and 115.8 kJ/mol for CF3OONO2, CF3, C(O)OONO2, and CF3OC(O)OONO2, respectively) and compared with previously reported. The investigation of stereoelectronic effects on the O─N bond, such asanomeric and mesomeric interactions was performed to provide their influence in the dissociation energy values using a detailed NBO (Natural Bond Orbital) analysis. Results indicate that the anomeric effect contributes significantly to the increase in electronic density on the antibonding O─N orbital (0.39553, 0.38689, and 0.38477 for CF3OONO2, CF3OC(O)OONO2, CF3C(O)OONO2 respectively). This is in agreement with the upward trend of the experimental and calculated dissociation energy (CF3OONO2 < CF3OC(O)OONO2 < CF3C(O)OONO2) and suggests that anomeric effect plays a key role in the bond dissociation.