Solvent and temperature effects on the tautomerization of a carbonitrile molecule: A conductor-like polarizable continuum model (CPCM) study

Article type: Research Article

Authors: Khanjari, Zohreh^a | Mohtat, Bita^{a; *} | Ghiasi, Reza^b | Djahaniani, Hoorieh^b | Behbahani, Farahnaz Kargar^a

Affiliations: [a] Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj, Iran | [b] Department of Chemistry, East Tehran Branch, Islamic Azad University, Tehran, Iran

Correspondence: [*] Corresponding author: Bita Mohtat, Department of Chemistry, Karaj Branch, Islamic Azad University, Karaj, Iran. E-mail: [email protected].

Abstract: This research examined the effects of solvent polarity and temperature on the tautomerization of a carbonitrile molecule at CAM-B3LYP/6-311G (d,p) level of theory. The selected solvents were n-hexane, diethyl ether, pyridine, ethanol, methanol, and water. The solvent effects were examined by the self-consistent reaction field theory (SCRF) based on conductor-like polarizable continuum model (CPCM). The solvent effects were explored on the energy barrier, frontier orbitals energies, and HOMO-LUMO gap. Dependencies of thermodynamic parameters (ΔG and ΔH) on the dielectric constants of solvents were also tested. Specifically, the temperature dependencies of the thermodynamics parameters were studied within 100–1000 K range. The rate constant of the tautomerism reaction was computed from 300 to 1200 K, in the gas phase.

Keywords: Tautomerism, solvent effect, temperature effect, thermodynamics parameters, rate constant

DOI: 10.3233/MGC-210016

Journal: Main Group Chemistry, vol. 20, no. 1, pp. 59-68, 2021