Noncovalent interactions play a crucial role in various biomolecular processes, including the remarkable catalytic activity of enzymes. The vibrational Stark effect (VSE) provides a unifying spectroscopic framework to quantify local electric fields—and thereby noncovalent interactions—in biomolecular environments. In this scheme, the investigation of X-H···π (X = C, N, O, S) interaction contributes to the understanding of interaction of X-H with aromatic amino acid residues, such as Trp, Phe, and Tyr. Recent studies have shown terminal alkyne C-H is a promising vibrational probe to study the interactions using various vibrational spectroscopy tools. Here, we investigate C-H···π interaction using 1-hexyne as solute in the solutions of derivatives of benzene-based solvents. By incorporating vibrational spectroscopic tools (FTIR and vibrational Stark spectroscopy) and computations (AMOEBA polarizable force field molecular dynamics simulations and DFT), a quantitative correlation between complex formation and calculated electric fields was established.
Ta et al. (Sun,) studied this question.