Accurate Single-Molecule Indicator of Solvent Effects.

The study of the microscopic structure of solvents is of significant importance for deciphering the essential solvation in chemical reactions and biological processes. Yet conventional technologies, such as neutron diffraction, have an inherent averaging effect as they analyze a group of molecules. In this study, we report a method to analyze the microstructure and interaction in solvents from a single-molecule perspective. A single-molecule electrical nanocircuit is used to directly analyze the dynamic microscopic structure of solvents. Through a single-molecule model reaction, the heterogeneity or homogeneity of solvents is precisely detected at the molecular level. Both the thermodynamics and the kinetics of the model reaction demonstrate the microscopic heterogeneity of alcohol-water and alcohol-n-hexane solutions and the microscopic homogeneity of alcohol-carbon tetrachloride solutions. In addition, a real-time event spectroscopy has been developed to study the dynamic characteristics of the segregated phase and the internal intermolecular interaction in microheterogeneous solvents. The development of such a unique high-resolution indicator with single-molecule and single-event accuracy provides infinite opportunities to decipher solvent effects in-depth and optimizes chemical reactions and biological processes in solution.