Connecting the Practice of Modern Qualitative and Quantitative NMR Analysis with Its Theoretical Foundation.

Abstract

This Perspective seeks to reconnect the current practice of nuclear magnetic resonance (NMR) spectroscopy in chemical structure and quantitative (qNMR) analysis with its roots in classical physics and quantum mechanics (QM). Rationales for this approach are derived from various angles, including focused reviews of the key parameters of the nuclear resonance phenomenon, the structural information richness of NMR spectra, and significant progress in both computational and spectrometer hardware. This provides collective reasoning for the reintegration of computational quantum mechanical spectral analysis (QMSA) into the contemporary practice of NMR spectral interpretation. Retethering operator-dependent visual phenotypic with QM-driven computational genotypic analysis yields more objective and accurate information by taking advantage of QM as the foundational reference point for NMR. Powerful computational tools for compound genotyping are available and evolve rapidly toward automation. In addition to enhancing the rigor and reproducibility of structure elucidation of new and the dereplication of known compounds, QM anchoring enables competent resolution of peak overlap, with resulting benefits in qNMR and low-field/benchtop NMR analysis. Furthermore, examination of common definitions and documentation practices shows that an evolutionary reconciliation of NMR terminology helps resolve ambiguities: shifting from phenotypic peak focus to genotypic QM-based pattern analysis is not only the logical next step when communicating structures of natural products and other molecules reproducibly but also a timely approach, as it yields QMSA-verified data for evolving knowledge bases for molecules of biomedical relevance.