Liquid-Phase Exfoliated 2D Nanomaterials for Enhanced Vibrational Circular Dichroism of Chiral Molecules

Abstract

Vibrational circular dichroism (VCD) spectroscopy is a powerful technique for stereochemical analysis, but its application is often limited by inherently weak polarization-dependent signal absorption intensities (e.g., 10^-4 to 10^-5). This study investigates liquid-phase exfoliated (LPE) two-dimensional (2D) nanomaterials as a readily accessible and versatile platform for enhancing molecular VCD signals. We explored the optical interactions between chiral molecules (R)- and (S)-1,1'-bi(2-naphthol) (BINOL) and a range of LPE 2D materials possessing diverse electronic properties: semiconducting 2H-WS₂, semimetallic 2H-TiS₂ and 2H-NbS₂, metallic 3R-NbS₂ and Ti₃C₂T_z, and magnetic metallic 2H-VS₂. Significant VCD signal enhancement for BINOL was observed, reaching up to 2 orders of magnitude relative to BINOL alone. Overall, the 2D materials induced varied effects, including signal enhancement, signal dampening, peak shifts, and inversion of VCD handedness. This work demonstrates potential platforms for modulating and enhancing molecular VCD characteristics, offering a promising route toward more sensitive chiroptical molecular analysis and detection.

Keywords: 2D Materials; Exfoliation; MXene; TMDC; Thin Film; Vibrational Circular Dichroism.