A new approach to recognizing the correct pattern of cross-peaks from a noisy 2D asynchronous spectrum by detecting intrinsic symmetry via the Kolmogorov-Smirnov test

Linchen Xie; Ran Guo; Limin Yang; Yukihiro Ozaki; Isao Noda; Yizhuang Xu; Kun Huang

doi:10.1039/d2cp05350k

A new approach to recognizing the correct pattern of cross-peaks from a noisy 2D asynchronous spectrum by detecting intrinsic symmetry via the Kolmogorov-Smirnov test

Phys Chem Chem Phys. 2023 May 10;25(18):12863-12871. doi: 10.1039/d2cp05350k.

Authors

Linchen Xie^{1

2}, Ran Guo^{2

3}, Limin Yang⁴, Yukihiro Ozaki^{2

5}, Isao Noda^{2

6}, Yizhuang Xu², Kun Huang¹

Affiliations

¹ School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China. huangkun@ustb.edu.cn.
² Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China. xyz@pku.edu.cn.
³ Beijing CKC, PerkinElmer Inc., Beijing 100015, P. R. China.
⁴ State Key Laboratory of Nuclear Physics and Technology, Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China. yanglm@pku.edu.cn.
⁵ School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo 669-1330, Japan.
⁶ Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA.

PMID: 37165857
DOI: 10.1039/d2cp05350k

Abstract

The characteristic cluster pattern of cross-peaks in a 2D asynchronous spectrum provides an effective way to reveal the specific physicochemical nature of subtle spectral changes caused by intermolecular interactions. However, the inevitable presence of noise in the 1D spectra used to construct a 2D asynchronous spectrum is significantly amplified, which poses a serious challenge in identifying the correct cluster pattern of the cross-peaks. While mirror symmetry occurs in some types of cross-peaks, it does not occur in other types. The Kolmogorov-Smirnov test provides a statistical means to check whether the mirror symmetry exists or not between a pair of cross-peaks covered by heavy noise. Thus, different types of cross-peak clusters can be distinguished by excavating intrinsic spectral features from the noisy 2D asynchronous spectrum. The effectiveness of this approach in investigating the nature of intermolecular interactions was showcased in both a simulated model system and a real artemisinin/N-methyl pyrrolidone system.