Multiple-quantum relaxation in the magic-angle-spinning NMR of 13C spin pairs

✍ Scribed by T. Karlsson; A. Brinkmann; P.J.E. Verdegem; J. Lugtenburg; M.H. Levitt

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 305 KB
• Volume: 14
• Category: Article
• ISSN: 0926-2040
• DOI: 10.1016/s0926-2040(99)00008-9

✦ Synopsis

We determine the decay rate constants of zero-, double-and single-quantum coherence for 13 C spin pairs in magic-angle-spinning solid-state NMR. The double-quantum coherence is excited by a C7 pulse sequence and converted into zero-quantum coherence by a frequency-selective pair of pr2 pulses. The zero-quantum coherence is reconverted into observable magnetization by a second pair of pr2 pulses followed by a second C7 sequence. In a magnetically dilute system where the 13 C-13 C distance is 0.296 nm, the relaxation rate constants are consistent with a model of uncorrelated random fields at the two labeled 13 C sites. In a fully-labelled system with a short 13 C-13 C distance of 0.153 nm, the measured rate constants are inconsistent with the uncorrelated random field model.