Multiple acquisitions in a single scan: exhausting abundant 1H polarization at fast MAS

Zhiwei Yan; Rongchun Zhang

doi:10.1016/j.jmr.2022.107338

Multiple acquisitions in a single scan: exhausting abundant ¹H polarization at fast MAS

J Magn Reson. 2023 Jan:346:107338. doi: 10.1016/j.jmr.2022.107338. Epub 2022 Nov 24.

Authors

Zhiwei Yan¹, Rongchun Zhang²

Affiliations

¹ South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter (SESM), South China University of Technology, Guangzhou 510640, PR China.
² South China Advanced Institute for Soft Matter Science and Technology (AISMST), School of Emergent Soft Matter (SESM), South China University of Technology, Guangzhou 510640, PR China; Guangdong Provincial Key Laboratory of Functional and Intelligent Hybrid Materials and Devices, South China University of Technology, Guangzhou 510640, PR China. Electronic address: zhangcr@scut.edu.cn.

PMID: 36463686
DOI: 10.1016/j.jmr.2022.107338

Abstract

Proton-detected solid-state NMR spectroscopy is emerging as a unique tool for atomic characterization of organic solids due to the boost of resolution and sensitivity afforded by the combined use of high magnetic field and ultrafast magic angle spinning (MAS). Here, we proposed a new set of proton-detected solid-state NMR sequences that hybrid multi-dimensional ¹H-¹H homonuclear chemical shift correlation (HOMCOR) and two-dimensional ¹H-¹³C heteronuclear chemical shift correlation (HETCOR) sequences into a single experiment, enabling the simultaneous acquisition of multidimensional HOMCOR and HETCOR spectra and thus significant time savings. Based on the core idea of exhausting ¹H polarization in each transient scan, we firstly demonstrated that 3D ¹H multiple-quantum (MQ) HOMCOR sequence can be combined with 2D HETCOR sequence into a single experiment, leading to the simultaneous acquisition of a 3D ¹H MQ HOMCOR and a 2D ¹H-¹³C HETCOR spectrum. Besides, we also showed that 2D ¹H/¹H double-quantum/single-quantum (DQ/SQ) and single-quantum/single-quantum (SQ/SQ) HOMCOR sequence can be simultaneously combined with HETCOR sequence either, and thus three spectra can be simultaneously obtained from one experiment, including 2D ¹H DQ/SQ, 2D ¹H SQ/SQ and 2D ¹H-¹³C HETCOR spectra. Since there is only one recycle delay in each experiment, experimental time is substantially reduced compared to separate acquisition of each multi-dimensional solid-state NMR spectrum. Furthermore, those new sequences can be implemented on any standard solid-state spectrometer with only one receiver. Thus, we foresee that these approaches can be valuable for the study of a broad range of molecular systems, including polymers, pharmaceuticals, covalent-organic frameworks (COF) and so on.

Keywords: Fast MAS; Multiple acquisitions; Multiple quantum; Proton detection; Solid-state NMR.