Elucidating the Structure–Spectrum Relationship of Choline and Citicoline: Approaches From Experimental FT-IR and Theoretical DFT/HF Methods

In this study, the structural and vibrational properties of choline and citicoline at the molecular level were investigated comprehensively through the integration of experimental and theoretical methods. The main purpose of the study is to provide an accurate interpretation of FT-IR spectra of these molecules and to contribute to molecular identification processes. Experimentally, spectral data obtained from pure citicoline powder using ATR/FT-IR spectroscopy were compared theoretically with Hartree–Fock (HF) and density functional theory (DFT) approaches; in this context, B3LYP functional and 6–311++G(d,p) basis set were taken as basis. Thanks to this method, supported by theoretical calculations, full vibrational (IR and Raman) spectra and structural parameters of choline and citicoline were modeled in detail, and systematic assignments were made to vibrational modes. The obtained findings show that experimental and theoretical data are in high agreement; this situation emphasizes the complementarity and reliability of both approaches, especially in terms of functional group analysis of citicoline molecule. In addition, this holistic analysis method provides a strong basis for predicting the potential interactions, chemical stabilities, and possible side effects of choline and citicoline molecules in biological systems at the molecular level. The obtained results contribute to the development of a deeper understanding of the roles of such compounds in biochemical processes, as well as providing guidance for structural optimization and targeted design studies in future pharmaceutical and biotechnological applications.