Theoretical study of ionization and one‐electron oxidation potentials of N‐heterocyclic compounds

Abstract

A number of density functionals was utilized to predict gas-phase adiabatic ionization potentials (IPs) for nitrogen-rich heterocyclic compounds. Various solvation models were applied to the calculation of difference in free energies of solvation of oxidized and reduced forms of heterocyclic compounds in acetonitrile (AN) for correct reproduction of their standard oxidation potentials. We developed generally applicable protocols that could successfully predict the gas-phase adiabatic ionization potentials of nitrogen-rich heterocyclic compounds and their standard oxidation potentials in AN. This approach is supported by a MPW1K/6-31+G(d) level of theory which uses SMD(UA0) approximation for estimation of solvation energy of neutral molecules and PCM(UA0) model for ionized ones. The mean absolute derivation (MAD) and root mean square error (RMSE) of the current theoretical models for IP are equal to 0.22 V and 0.26, respectively, and for oxidation potentials MAD = 0.13 V and RMSE = 0.17.

Are the reduction and oxidation properties of nitrocompounds dissolved in water different from those produced when adsorbed on a silica surface? A DFT M05-2X computational study

“…The parameters of the compounds in this study that characterize their ability to be reduced or oxidized are presented in Tables and 2. Despite the accuracy of the chosen computational method and according to our previous publications, we cannot expect the experimental accuracy in case of silica for the values of adsorption energy. Therefore, we presume that the parameters presented in Tables and 2 that characterize electron donor and acceptor properties of adsorbed species are not as accurate as in the case of gas phase or solution calculations.…”

“…It has been previously shown that M05/tzvp density functional theory (DFT) augmented by inclusion of continuum model of hydration provides nearly experimental accuracy in the prediction of the values of redox potentials. [31,32] In this study, the same level of computational modeling is used for the prediction of redox potentials for nitrocompounds TNT, DNT, DNAN, and NTO, dissolved in water and adsorbed on a silica surface, taken here as the (001) surface of a-quartz. To determine whether the compounds in this study will be able to be reduced under natural conditions, we used a wide range of redox potentials which characterize the half-reaction in the iron system: Fe(II)/Fe(III) system and zero valence (metallic) iron Fe(0).…”

“…Recently, we have verified the accuracy of different quantum‐chemical solvation models to predict reduction and oxidation potentials for a wide range of organic compounds (mostly nitrogen containing environmental contaminants) in several organic solvents including water. It has been previously shown that M05/tzvp density functional theory (DFT) augmented by inclusion of continuum model of hydration provides nearly experimental accuracy in the prediction of the values of redox potentials . In this study, the same level of computational modeling is used for the prediction of redox potentials for nitrocompounds TNT, DNT, DNAN, and NTO, dissolved in water and adsorbed on a silica surface, taken here as the (001) surface of α‐quartz.…”

DFT study on the tautomerism of organic linker 1H-imidazole-4,5-tetrazole (HIT)

“…In the present scenario, the role of heterocyclic compounds as an organic linker is ubiquitous due to their strong metal coordination ability. Most of these heterocyclic compounds inherently exhibit tautomeric forms [12][13][14]. These tautomeric forms can provide versatile organic linkers for the design of an efficient MOF with desired pore size.…”

Computational Study on Structure and Properties of New Energetic Material 3,7-BIS(DINITROMETHYLENE)-2,4,6,8-TETRANITRO-2,4,6,8-TETRAAZA-BICYCLO[3.3.0]OCTANE

“…18,19 Vibrational analyses at the same level of theory were performed to confirm that all of the optimized structures correspond to be the local energy minima on the potential energy surfaces. Meanwhile, natural bond orbital (NBO) analysis 20 was carried out to investigate the trigger bond.…”