Ab-Initio Study of Hydrogen Bond Networks in 1,2,3-Triazole Phases.

Christopher Peschel,Daniel Sebastiani,Christian Dreßler

doi:10.3390/molecules25235722

Christopher Peschel, Daniel Sebastiani + Show 1 more

Open Access

https://doi.org/10.3390/molecules25235722

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Abstract

The research in storage and conversion of energy is an everlasting process. The use of fuel cells is very tempting but up to now there are still several conceptual challenges to overcome. Especially, the requirement of liquid water causes difficulties due to the temperature limit. Therefore, imidazoles and triazoles are increasingly investigated in a manifold of experimental and theoretical publications as they are both very promising in overcoming this problem. Recently, triazoles were found to be superior to imidazoles in proton conduction. An ab-initio molecular dynamics simulation of pure triazole phases for investigating the behavior of both tautomer species of the triazole molecule has never been done. In this work, we investigate the structural and dynamical properties of two different solid phases and the liquid phase at two different temperatures. We are able to show how the distinct tautomers contribute to the mechanism of proton conduction, to compute dynamical properties of the four systems and to suggest a mechanism of reorientation in solid phase.

Highlights

Modern society demands an ongoing development in energy conversion, storage and overall efficiency. This is caused by a progressive increase in world population and the use of electronic devices, which is undeniably further growing in the decades
Within ab-initio molecular dynamics simulation timescales it is reasonable that there is no diffusion determinable which leads to zero diffusion coefficient in solid phases
When we investigated imidazole-based polymers [52] with NMR methods we saw great potential in proton conduction and storage originating from the nitrogen-based imidazole part of the polymer

Summary

Introduction

Modern society demands an ongoing development in energy conversion, storage and overall efficiency. We have investigated liquid 1,2,3-triazole at two different temperatures (413 K and 313 K) and two different crystal structures namely an orthorhombic phase at 280 K and a monoclinic phase at 269 K When it comes to triazoles, lately the conduction of lithium ions received attention [46,47,48] which makes our research even more important as an understanding of the proton conducting properties can be utilized to investigate lithium diffusion from a different perspective. The 2H-triazole instead carries the acidic hydrogen atom at the middle nitrogen atom making it symmetrical This symmetry influences the behavior dramatically as the resulting dipole is 42 times bigger in case of the non symmetrical 1H-triazole [45]. We show that the dynamics of our simulated systems reproduces the diffusion coefficient of experimental data [43]

Orientation in Liquid and Crystalline Phases

H-Network and Role of Tautomers

Reorientation Mechanism

Diffusion Coefficients

Discussion

Materials and Methods