Effects of Morphology and Solvent/Temperature on THz Spectra: Take Nucleosides as Example
Fang Wang1, Haifeng Lin2, Jiawen Tong1
1College of Electronic Engineering, Nanjing XiaoZhuang University, Nanjing 211171, China.
Molecules (Basel, Switzerland)
|February 25, 2023
Summary
Terahertz (THz) spectroscopy reveals how water molecules influence nucleoside properties. Crystalline water significantly impacts THz spectra, highlighting the importance of crystal structure in understanding these compounds.
Area of Science:
- Solid-state chemistry
- Molecular spectroscopy
- Computational chemistry
Background:
- Hydrates exhibit distinct properties compared to anhydrous compounds.
- Nucleosides are fundamental biological molecules whose solid-state properties are crucial for understanding their function.
Purpose of the Study:
- To investigate the influence of water molecules on the terahertz (THz) spectra of nucleosides.
- To analyze the structural and vibrational properties of nucleoside crystals using experimental and theoretical methods.
- To elucidate the role of molecular morphology, solvent effects, and temperature on THz spectra.
Main Methods:
- Experimental terahertz (THz) spectroscopy using Fourier-transform infrared spectroscopy (FTIR) for five nucleosides in solid and liquid phases (0.5–9 THz).
- Theoretical analysis using the generalized energy-based fragmentation approach under periodic boundary conditions (PBC-GEBF) for lattice energy, geometric structure, and vibrational spectra.
- Investigation of monomer, polymer, and crystal morphologies, as well as implicit and explicit water solvent models.
Main Results:
- Low-frequency THz spectral bands primarily originate from collective molecular vibrations, reflecting molecular structure and spatial distribution.
- Cell-stacking energy significantly influences the spectra, indicating that crystal structures under periodic boundary conditions are essential for accurate experimental description.
- Hydrophobic forces are key drivers of new chemical bonds and inter-molecular interactions; crystalline water strongly affects THz spectra, while free water has minimal impact.
Conclusions:
- The crystal structure of nucleosides plays a critical role in determining their terahertz spectral properties.
- Understanding the interplay between water molecules, particularly crystalline water, and nucleoside structures is vital for characterizing their physical and chemical behavior.
- Periodic boundary condition-based computational models are necessary for accurately simulating and interpreting experimental THz spectra of nucleoside crystals.
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