Benchmark calculations for bond dissociation energies and enthalpy of formation of chlorinated and brominated polycyclic aromatic hydrocarbons

Shenying Xu; Quan-De Wang; Mao-Mao Sun; Guoliang Yin; Jinhu Liang

doi:10.1039/d1ra05391d

Benchmark calculations for bond dissociation energies and enthalpy of formation of chlorinated and brominated polycyclic aromatic hydrocarbons

RSC Adv. 2021 Sep 6;11(47):29690-29701. doi: 10.1039/d1ra05391d. eCollection 2021 Sep 1.

Authors

Shenying Xu¹, Quan-De Wang^{1

2}, Mao-Mao Sun², Guoliang Yin¹, Jinhu Liang^{1

3}

Affiliations

¹ Faculty of Materials and Chemical Engineering, Yibin University Yibin Sichuan 644000 People's Republic of China quandewang@cumt.edu.cn.
² Low Carbon Energy Institute and School of Chemical Engineering, China University of Mining and Technology Xuzhou 221008 People's Republic of China.
³ School of Environment and Safety Engineering, North University of China Taiyuan 030051 People's Republic of China jhliang@nuc.edu.cn.

Abstract

Thermodynamic properties, i.e., bond dissociation energies and enthalpy of formation, of chlorinated and brominated polycyclic aromatic hydrocarbons play a fundamental role in understanding their formation mechanisms and reactivity. Computational electronic structure calculations routinely used to predict thermodynamic properties of various species are limited for these compounds due to large computational cost to obtain accurate results by employing high-level wave function theory methods. In this work, a number of composite model chemistry methods (CBS-QB3, G3MP2, G3, and G4) are used to compute bond dissociation energies and enthalpies of formation of small to medium-size chlorinated and brominated polycyclic aromatic hydrocarbon compounds. The enthalpy of formation is derived via the atomization method and compared against the recommended values. Statistical analysis indicates that G4 is the best method. For comparison, three commonly used density functional theory (DFT) methods (M06-2X, ωB97X-D and B2PLYP-D3) with various basis sets including 6-311++G(d, p), cc-pVTZ, and cc-pVQZ in the prediction of bond dissociation energies and enthalpies of formation have been tested using the optimized geometries at the same M06-2X/6-311++G(d, p) level of theory. It is found that ωB97X-D/6-311++G(d, p) shows the best performance in computing the bond dissociation energies, while ωB97X-D/cc-pVTZ exhibits the best prediction in enthalpy of formation of the studied reaction systems. The structural effect on the bond dissociation energies and enthalpy of formation of chlorinated and brominated polycyclic aromatic hydrocarbons are then systematically analyzed. Based on comparisons of the various methods, reliable DFT methods are recommended for future theoretical studies on large chlorinated and brominated polycyclic aromatic hydrocarbons considering both accuracy and computational cost. This work, to the authors' knowledge, is the first to systematically benchmark theoretical methods for the accurate prediction of thermodynamic properties for chlorinated and brominated polycyclic aromatic hydrocarbons.