Raman spectroscopic and theoretical investigation of polarity regulation and hydrogen bonding in DMSO binary systems

This study elucidates the molecular mechanisms underlying polarity modulation in dimethyl sulfoxide (DMSO)-based binary solvent systems, a critical factor for tuning solvent properties in chemical and biological applications. By integrating Raman spectroscopy with density functional theory (DFT (B3LYP/6-311G (d, p) basis set used)) calculations, we systematically investigated intermolecular interactions (particularly hydrogen bonding) in DMSO-water/ethanol/benzene systems. Our results reveal: A concentration-dependent structural reorganization at X_{V(W/Et/B)/V(Total)} = 0.4 across all systems, accompanied by an anomalous redshift of the CH_{3 (D-Et)} stretching mode (X_{V(Et)/V(Total)} = 0.8-0.9) in the system_(D-Et). Propose Type I/II assuming that the polarity gradient (water>ethanol>benzene) of the solvent effect governs the spectral behavior. In the binary system_(DW), the S=O_D-W stretching vibration peak of 1045 cm^-1 embodies both divisive (1045 cm^-1 → 1018 cm^-1/1028 cm^-1) and competitive behavior. These findings provide fundamental insights into dynamic polarity regulation and hydrogen-bonding interactions in tunable solvent systems, with direct implications for solution-phase process design.