title: Origins of the stability of imidazole-imidazole, benzene-imidazole, and benzene-indole dimers: CCSD(T)/CBS and SAPT calculations.
abstract: The respective structures and stabilities of imidazole-imidazole, benzene-imidazole, and benzene-indole dimers have been investigated using different DFT-D functional, MP2, CCSD(T), and SAPT levels of theory with a medium basis set. Comparative analysis of binding energies and structural parameters of the dimers points to a preference for stacking contact or hydrogen bond in an imidazole-imidazole dimer. In contrast, a T-shaped configuration with H-π interaction is maximally advantageous for benzene-imidazole and benzene-indole dimers. High-level ab initio calculations at the CCSD(T)/CBS and DFT-SAPT levels show that classical hydrogen-bonded tilted imidazole-imidazole dimer is a global minimum structure and that it has high electrostatic energy. However, for benzene-imidazole and benzene-indole dimers, the global minimum (N-H···π) structure has high electrostatic energy as well as dispersion energy.
authors.affiliation: Department of Theoretical and Computational Molecular Science, Institute of Molecular Science, Myodaiji, Okazaki 444-8585, Aichi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Karthikeyan
authors.forename: Shigeru
authors.initials: S
authors.lastname: Nagase
mesh_terms: D001554:Benzene / Q000737:chemistry*; D019281:Dimerization; D006860:Hydrogen Bonding; D007093:Imidazoles / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry*; D008958:Models, Molecular; D013816:Thermodynamics
chemical_list: D007093:Imidazoles; D007211:Indoles; D001554:Benzene