A comparison of the C‒H bond dissociation enthalpies of sulfur-containing fused heterocyclic compounds to the C‒H bond dissociation enthalpies in other heterocycles

Abstract

The C‒H bond dissociation enthalpies (BDEs) of 26 N, O, S-containing mono-heterocyclic compounds were assessed by the composite high-level ab initio methods G4 and CBS-QB3. In addition, the C‒H BDEs of 32 heterocyclic compounds were evaluated by 13 density functional theory methods. The BMK method showed the lowest root mean square error of 7.2 kJ/mol and the correlation coefficient (R²) was 0.9874 after being compared with the experimental values. Subsequently, we used this method to study the C‒H BDE values of the different positions as well as the substituent effects on benzene and heterocycles in sulfur-containing fused heterocyclic compounds. Both the natural charge distributions of benzo[b]thiophene and benzothiazole and natural spin densities of benzo[b]thiophene derivative radicals were conducted by NBO analysis for further understanding the essence of the C‒H bond.

GRAPHICAL ABSTRACT

Keywords:

• C‒H bond dissociation enthalpies
• sulfur-containing fused heterocyclic compounds
• DFT
• substituent effect
• NBO analysis

Acknowledgements

We also thank Shanghai Supercomputer Center for the computational resources.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This study was financed by the graduate research and innovation funding [13KY0402].

Supplemental material

Supplemental data for this article can be accessed at http://dx.doi.org/10.1080/17415993.2014.996222.