Nature of the water/aromatic parallel alignment interactions

• Published in: Journal of computational chemistry Vol. 36; no. 3; pp. 171 - 180
• Main Authors: Mitoraj, Mariusz P., Janjić, Goran V., Medaković, Vesna B., Veljković, Dušan Ž., Michalak, Artur, Zarić, Snežana D., Milčić, Miloš K.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 30.01.2015; Wiley Subscription Services, Inc
• Subjects: Chemical bonds; Dispersion; Electrostatics; energy decomposition; Mathematical analysis; Models, Theoretical; Molecular chemistry; NOCV ETS; SAPT; supramolecular method; Symmetry; Thermodynamics; Water - chemistry; water/aromatic parallel interactions; NOCV ETS; SAPT; energy decomposition; supramolecular method; water/aromatic parallel interactions
• ISSN: 0192-8651; 1096-987X
• DOI: 10.1002/jcc.23783

The water/aromatic parallel alignment interactions are interactions where the water molecule or one of its OH bonds is parallel to the aromatic ring plane. The calculated energies of the interactions are significant, up to ΔECCSD(T)(limit) = −2.45 kcal mol−1 at large horizontal displacement, out of benzene ring and CH bond region. These interactions are stronger than CH···O water/benzene interactions, but weaker than OH···π interactions. To investigate the nature of water/aromatic parallel alignment interactions, energy decomposition methods, symmetry‐adapted perturbation theory, and extended transition state‐natural orbitals for chemical valence (NOCV), were used. The calculations have shown that, for the complexes at large horizontal displacements, major contribution to interaction energy comes from electrostatic interactions between monomers, and for the complexes at small horizontal displacements, dispersion interactions are dominant binding force. The NOCV‐based analysis has shown that in structures with strong interaction energies charge transfer of the type π → σ*(OH) between the monomers also exists. © 2014 Wiley Periodicals, Inc. The nature of interactions in parallel water/benzene complexes is investigated using ab initio calculations and energy decomposition methods. The calculated energies of the interactions are significant at large horizontal displacement. These interactions are stronger than CH···O water/benzene interactions, but weaker than OH···π interactions. Both energy decomposition methods, SAPT and ETS‐NOCV, agree the electrostatic force is more important, responsible for bonding in water/benzene parallel complexes at large horizontal displacement.