Identification of Enantiomers Using Low-Frequency Raman Spectroscopy

Chiral induction in the crystallization of KIO3 and LiIO3: the role of amino acids in controlling the chirality of inorganic crystals

Chiral induction in crystals has attracted significant attention due to its implications for developing chiral materials and understanding mechanisms of symmetry-breaking enantioselective crystallization of naturally occurring chiral minerals. Despite its potential use in chiral discrimination, this area remains largely unexplored. Here, we investigate chiral induction during crystallization of naturally occurring chiral KIO3 and LiIO3 minerals using arginine and alanine as chiral inducers. The chiral nature of the crystallization and the effect of the chiral inducers were examined using circular dichroism, polarimetry, and low-frequency Raman spectroscopy. The impact of chiral molecules on the rate and final crystal structure was studied by electron microscopy including SEM and TEM. We demonstrate that it is possible to control the chirality with chiral exogenous molecules, mainly amino acids. Understanding chiral induction in crystal growth may open avenues for controlled assembly of chiral materials and development of novel functional materials with unique properties.

Chiral Discrimination of Penicillamine Enantiomers: The Role of Aggregation-Caused Quenching in Achieving High Selectivity

The recognition and separation of chiral isomers are of great importance in both industrial and biological applications. In this study, a chiral recognition system based on electrochemiluminescence was established for the detection of penicillamine (PA) enantiomers. The system utilized a homochiral [Zn2(BDC)(d-lac)] (Zn-BL) platform for the uniform distribution of Ru(bpy)32+ nanoparticles, effectively mitigating aggregation-caused quenching. The chiral recognition ability of Zn-BL was tested to distinguish between PA enantiomers, and the results indicated a substantial increase in the chiral electrochemiluminescence (ECL) signal when l-PA was present, in contrast to d-PA. The mechanism underlying ECL chiral discrimination was investigated using water contact angle measurements, DFT calculations, and electrochemical characterization. The system exhibited high selectivity, stability, and reproducibility for PA enantiomer detection. Furthermore, the proposed method can accurately identify one enantiomer of PA in a mixture. This study provides a reliable and sensitive approach for achieving the highly selective detection of chiral molecules.