Double Orthogonal Sample Design Scheme and Corresponding Basic Patterns inTwo-Dimensional Correlation Spectra for Probing Subtle Spectral Variations Caused byIntermolecular Interactions

摘要

This paper introduces a new approach named double orthogonal sample design scheme (DOSD) to probeintermolecular interactions based on a framework of two-dimensional (2D) correlated spectroscopy. In thisapproach, specifically designed concentration series are selected according to the mathematical analysis onorthogonal vectors to generate useful 2D correlated spectra. As a result, the interfering portion can be completelyremoved from both synchronous and asynchronous spectra, and complementary information concerningintermolecular interactions can be obtained from the set of 2D spectra. A model system, where intermolecularinteractions occur between two solutes in a solution, is used to investigate the behavior of 2D correlatedspectra generated by using the DOSD approach. Simulation results demonstrate that the resultant spectralpatterns can reflect subtle spectral variation in bandwidths, peak positions, and absorptivities brought aboutby intermolecular interaction, which are hardly visualized in conventional ID spectra because of the severeband-overlapping problem. The ability to reveal a subtle variation in a characteristic peak in detail by usingthe DOSD approach provides a new opportunity to understand the nature of intermolecular interactions froma molecular structural point of view. Intermolecular interactions between iodine and benzene in CCl4 solutionswere investigated by using the proposed DOSD approach to prove the applicability of the DOSD method inreal chemical systems.