Solvent-Dependent Self-Association of Chiral 2-Acetoxy-2-Phenylacetic Acid Revealed by Infrared and Vibrational Circular Dichroism Spectroscopy
Year: 2026
Type: preprint
Abstract: The solvent-dependent self-association of chiral 2-acetoxy-2-phenylacetic acid (APA) was investigated in CCl4, CDCl3, and DMSO-d6 solvents, using infrared (IR) and Vibrational Circular Dichroism (VCD) spectroscopy, supported by density functional theory calculations. Concentration-dependent IR measurements revealed progressive formation of self-associated species in CCl4 and CDCl3, whereas no significant concentration dependence was observed in DMSO-d6. Band-fitting analysis and comparison of experimental and calculated IR and VCD spectra indicate that hydrogen-bonded APA dimers with an antiarrangement of the phenyl rings are the dominant self-associated species in CCl4 and CDCl3. In contrast, the high polarity of DMSO-d6 suppresses self-association and favors a doubly hydrogen-bonded 1:1 APA–DMSO-d6 complex involving O-H…O and C-H…O interactions. The results demonstrate that solvent polarity strongly controls the balance between solutesolute and solute-solvent hydrogen bonding and highlight the sensitivity of VCD spectroscopy to molecular association and intermolecular interactions in solution.
Source: ChemRxiv
Authors: Anwesha Datta, Tapas Chakraborty
Institution: Indian Association for the Cultivation of Science
Language: English
Subfield: Spectroscopy
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7208727114