A comprehensive study of the solvent effects on the cycloaddition reaction of diethyl azodicarboxylate and ethyl vinyl ether: Efficient implementation of QM and TD-DFT study

Abstract

In this work, quantum chemistry calculations performed to study the kinetics and thermodynamic parameters of [212] cycloaddition reaction of diethyl azodicarboxylate and ethyl vinyl ether in eighty-three solvents and gas phase. The solvent effect on the reaction path and electron density of the C2AN6 critical bond as the reaction coordinate at the TS was investigated. Calculated rate constants in various solvents showed that increase in the activation dipole moment accelerates the reaction. Based on the time-dependent studies, using a conductor like polarizable continuum model solvation model, the solvent effects on the excitation energies of the reactants and transition states (TSs) and the corresponding chemical shifts were analyzed. Finally, some correlations between the rate constant and quantum reactivity indices such as electrophilicity index, chemical hardness, and electronic chemical potential were investigated.

Thermal decomposition mechanisms of the ionic liquids based on α-amino acid anion and N7,N9-dimethyladeninium cation: Quantum chemistry approach

“…Increase in the alkyl side chain length at the TS(B4) and TS(B5) decreases the electron density of C11…O27 bond. In the previous studies, we have shown the existence of a reasonable correlation between some of the molecular orbital and topology properties with the kinetic parameters [31,32]. Although our database of the ionic liquids is small in the present study, meanwhile the possible correlation between the Gibbs free energy of activation and electron density of the forming C12…O26 bond at the TS was investigated and depicted in Fig.…”

“…This figure shows that activation Gibbs free energy can be considered as a function of the electron density of the reaction coordinate. Obtained linear correlation is according to the previous works [31,32].…”

Understanding the role of noncovalent interactions on the rate of some Diels‐Alder reactions in different solvents

“…The energy difference between the highest occupied molecular orbital and the lowest unoccupied molecular orbital of the involved reactants controls the reaction kinetics. In the other words, a smaller energy difference between the frontier molecular orbitals corresponds with a higher rate of DA reaction …”

“…The obtained results indicate that endo product proportion in the solution phase is more than exo product in comparison with gas phase. Moreover, theoretical studies on different cycloaddtions reactions indicated that solvents have remarkable effects on the charge transfer, molecular orbital interactions, kinetic and thermodynamic parameters, IR vibrational frequencies at the TSs, topological parameters at the bond critical points and mechanism of the reaction . Although, in all cases, a change in the mentioned parameters was described in the presence of the solvent in comparison with gas phase, while our aim here, is to determine the nature of the solvent effects on different types of cycloaddition reactions (composed of different reactants) from the molecular viewpoint through the noncovalent interaction analysis.…”

DFT investigation and molecular dynamic simulation on the selective complexation of cis-cyclic nanopeptides with alkaline earth metal ions

“…Binding enthalpy of complexation (∆H) shows that oxygen-metal complexes of all CPs and only Be 2+ -N complex are exothermic in the gas phase and water.Calculated binding Gibbs free energies (∆G) inTable 1, reveals that Be 2+ -CPs complexes are the most stable complexes and confirmed that CPs have selective complexation with Be 2+ ion. Moreover, it is found better interaction of Be 2+ with CP2> CP3> CP1 and solvents have an important role in the interaction between the metal ions and CPs[54][55][56].…”