–NH2 Driven Dynamic Reconstruction of Hydrogen-Bond Networks in 3-Aminopropanol–Water System Revealed by Two-Dimensional Correlation Raman Spectroscopy

The hydrogen-bond (HB) network dynamics and intermolecular interactions in 3-aminopropanol (3AP)–water mixtures were systematically investigated using spontaneous and stimulated Raman spectroscopy (SRS), two-dimensional correlation Raman spectroscopy (2D Raman-COS), and density functional theory (DFT) calculations. Concentration-dependent Raman spectral analyses revealed distinct vibrational shifts in −OH, −NH₂, and −CH₂ stretching modes, with nonlinear trends and critical transitions at 3AP volume fractions of 0.3 and 0.7. 2D Raman-COS demonstrated preferential −NH₂ restructuring of the HB network, followed by −CH₂ and water OH perturbations, indicating a sequential response mechanism. DFT calculations elucidated the stable configurations of the 3AP-(H₂O)₂, 3AP-H₂O, and (3AP)₂–H₂O clusters, demonstrating the competitive O–H:N/O HB synergy in the 3AP–water system and validating the molecular basis of the three-stage solvation mechanism. This study provides molecular-level insights into the dynamic regulation of solvent microenvironments by amphiphilic molecules, offering a new perspective for understanding HB network reorganization in solution systems.