Theoretical study on the coupling of imidazole derivatives and haloalkanes: investigation of structures, effects of substituents and Gibbs free energy of reactions

N-Arylazoles which are produced from coupling aryl halides and imidazoles are important building blocks in numerous agrochemicals, pharmaceuticals, biological active compounds, and N-heterocyclic carbene chemistry (1-2). In this work density functional theory has been used for investigation of the structure and formation of some N-arylazole compounds. For this purpose the geometries of all N-arylazoles were optimized with B3LYP method combined with SVP basis set. Vibrational frequency analyses, was calculated at the same level of theory, indicated that optimized structures are located at the stationary points corresponding to local minima without any imaginary frequency. The solvation energy (Gsolv) was calculated with the CPCM model by using DMF as a solvent. After that the Gibbs free energy in solution was calculated by using equation Ggas + Gsolv = G(aq).We considered substitution effect including H, F, Me and CF3 groups on imidazole and 1,4-diboromo and 1,4-dichloroarylhalids for synthesis of N-arylazole compounds (see Figure 1). Our calculations show that the G(aq)amounts for all N-Arylazole compounds is exothermic and those with H and CF3groups as R substituents have maximum and minimum amount of G(aq), respectively. About aryl halids, it should be noted that the best obtained results is for 1,4-diboromo compound.