Structures and spectroscopic properties of low-energy candidate structures for toluene-(H2O)n (n=1-10) clusters

In this study, the dynamic behavior, geometric structure, electron density parameters and infrared spectra for toluene(T)-water(W) systems were calculated using molecular dynamics simulation, quantum chemistry calculation and wavefunction analysis. Dynamic simulations demonstrate that there are three interaction ways, H-w...pi(T), H-w...C-T and O-w...C-T, in TW system, and due to these interactions, each toluene can form 5 similar to 10H-bonds with water molecules, indicating that the toluene are easy to form H-bonds with H2O particularly at low temperature, while high temperature is harmful for that. Analyses of the TWn(n=1-10) cluster by quantum chemistry calculations and wavefunction analysis indicate that H-W...pi(T) is primarily responsible for the stabilization of TWna (n=1-2), while O-W...H-T is primarily responsible for the stabilization of TWna (n=3-10). In addition, H-w...pi(T), H-w...C-T and O-w...C-T show the dispersion and electrostatic nature. Furthermore, the degeneracy and delocalization of free OH and donor O-H modes are changed due to the formation of H-w...pi(T), H-w...C-T and O-w...C-T. The results displayed here have potential application prospects for the development of molecular recognition systems involving aromatic interactions. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

In this study, the dynamic behavior, geometric structure, electron density parameters, and infrared spectra for toluene-water systems were investigated using molecular dynamics simulation, quantum chemistry calculation, and wavefunction analysis. The results showed that toluene molecules can easily form multiple H-bonds with water molecules, with primary contributions to stabilization coming from H-W...pi and O-W...H-T interactions.