Zhang W, Chen S, Cai S, Chen Z. Detection and characterization of intermolecular multiple-quantum coherence NMR signals of IS (I=1/2; S=3/2) spin systems.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2011;
78:1051-1057. [PMID:
21216661 DOI:
10.1016/j.saa.2010.12.047]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 12/10/2010] [Accepted: 12/14/2010] [Indexed: 05/30/2023]
Abstract
Intermolecular multiple-quantum coherences (iMQCs) have some intrinsic properties different from conventional single-quantum coherences in solution NMR. In this paper, we extended our study to heteronuclear iMQCs in IS (I=1/2, S=3/2) spin systems. A sample of sodium chloride (NaCl) water solution was taken as an example. Heteronuclear COSY revamped by asymmetric Z-gradient echo detection (CRAZED) experiments were performed. One- and two-dimensional heteronuclear iMQC spectra were obtained. The quantum-mechanical treatment was used to deduce the signal expressions. Magic angle experiments validate that the signals are indeed from intermolecular dipolar interaction and insensitive to the imperfection of radio-frequency (RF) flip angles. Both experimental results and theoretical analysis indicate that heteronuclear CRAZED experiment allows coherence transfer from spin-3/2 nuclei to spin-1/2, and vice verse. Furthermore, the dependences of iMQC signal intensities on RF pulse flip angles follow the same rules as those for heteronuclear IS (I=1/2, S=1/2 or 1) spin systems.
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