Rapid Structural Analysis of Minute Quantities of Organic Solids by Exhausting <sup>1</sup> H Polarization in Solid-State NMR Spectroscopy Under Fast Magic Angle Spinning
Zhiwei Yan, Rongchun Zhang
Abstract
Solid-state nuclear magnetic resonance (NMR) often suffers from significant limitations due to the inherent low signal sensitivity when low-γ nuclei are involved. Herein, we report an elegant solid-state NMR approach for rapid structural analysis of minute amounts of organic solids. By encoding staggered chemical shift evolution in the indirect dimension and staggered acquisition in the 1H dimension, a proton-detected homonuclear 1H/1H and heteronuclear 13C/1H chemical shift correlation (HETCOR) spectrum can be obtained simultaneously in a single experiment at a fast magic-angle-spinning (MAS) condition with barely increasing the experimental time. We further show that during the conventional 1H-detected HETCOR experimental time, multiple homonuclear 1H/1H correlation spectra can be recorded in addition to the HETCOR spectrum, enabling the determination of 1H–1H distances. We establish that abundant 1H polarization can be efficiently manipulated and fully utilized in proton-detected solid-state NMR spectroscopy for extraction of more critical structural information and thus reduction of the total experimental time.