Robust Computation and Analysis of Vibrational Spectra of Layered Framework Materials Including Host–Guest Interactions

• Published in: Journal of chemical theory and computation 2024-11, Vol.20 (21), p.9547-9561
• Main Authors: Bas, Ekin Esme, Garcia Alvarez, Karen Marlenne, Schneemann, Andreas, Heine, Thomas, Golze, Dorothea
• Format: Article
• Language: English
• Subjects: Chemical bonds; Chemical synthesis; Computation; Correlation; Covalent bonds; Dipole moments; Infrared analysis; Infrared spectra; Molecular dynamics; Porous materials; Raman spectra; Robustness; Software; Solvents; Spectroscopy and Excited States; Tensors; Time correlation functions; Vibration monitoring; Vibrational spectra
• ISSN: 1549-9618; 1549-9626; 1549-9626
• DOI: 10.1021/acs.jctc.4c01021

Layered framework materials, a rapidly advancing class of porous materials, are composed of molecular components stitched together via covalent bonds and are usually synthesized through wet-chemical methods. Computational infrared (IR) and Raman spectra are among the most important characterization tools for this material class. Besides the a priori known spectra of the molecular building blocks and the solvent, they allow for in situ monitoring of the framework formation during synthesis. Therefore, they need to capture the additional peaks from host–guest interactions and the bands from emerging bonds between the molecular building blocks, verifying the successful synthesis of the desired material. In this work, we propose a robust computational framework based on ab initio molecular dynamics (AIMD), where we compute IR and Raman spectra from the time-correlation functions of dipole moments and polarizability tensors, respectively. As a case study, we apply our methodology to a covalent organic framework (COF) material, COF-1, and present its AIMD-computed IR and Raman spectra with and without 1,4-dioxane solvent molecules in its pores. To determine robust settings, we meticulously validate our model and explore how stacking disorder and different methods for computing dipole moments and polarizabilities affect IR and Raman intensities. Using our robust computational protocol, we achieve excellent agreement with experimental data. Furthermore, we illustrate how the computed spectra can be dissected into individual contributions from the solvent molecules, the molecular building blocks of COF-1, and the bonds connecting them.