Interaction in the indole⋯imidazole heterodimer: structure, Franck–Condon analysis and energy decomposition

Hill, J. G. and Das, A. (2014) Interaction in the indole⋯imidazole heterodimer: structure, Franck–Condon analysis and energy decomposition. Physical Chemistry Chemical Physics, 16(23), pp. 11754-11762. (doi: 10.1039/c4cp01360c)

Abstract

The complex of indole and imidazole has been studied using a combination of theoretical chemistry techniques, with the relevant calculations compared to existing experimental resonant two-photon ionisation data. Results of fitted multidimensional Franck–Condon simulations based on ground and excited state geometry optimizations and harmonic vibrational frequencies confirm that the V-shaped herringbone structure is that observed by experiment. The ground state interaction energy of these important biomolecular building blocks has been evaluated at a benchmark quality level using explicitly correlated coupled cluster theory, and the V-shaped structure is shown to be approximately 2 kcal mol−1 more strongly bound than other possible conformers. The non-covalent interaction energy is decomposed into physical components using symmetry-adapted perturbation theory and it can be seen that although electrostatics dominate the interaction, dispersion plays a vital role in determining the optimal geometry.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Hill, Dr John
• Authors: Hill, J. G., and Das, A.
• College/School: College of Science and Engineering > School of Chemistry
• Journal Name: Physical Chemistry Chemical Physics
• Publisher: Royal Society of Chemistry
• ISSN: 1463-9076
• ISSN (Online): 1463-9084