Supercycled SWf-TPPM sequence for heteronuclear dipolar decoupling in solid-state nuclear magnetic resonance

Refocused continuous-wave decoupling: A new approach to heteronuclear dipolar decoupling in solid-state NMR spectroscopy

“…attention has been devoted to improving the broadbandedness of the decoupling through frequency sweeping and supercycling, leading to decoupling sequences such as swept TPPM (SW f -TPPM), 12,13 swept SPINAL (SW f -SPINAL), 14 and supercycled-swept TPPM. 15 From comparative studies, it is evident that the optimal decoupling sequence to a large extent depends on the experimental conditions, including in particular the magic-angle-spinning (MAS) frequency and the applicable decoupling rf field strength. 16 These two parameters are of considerable practical importance as both sample spinning and high-power rf irradiation may cause substantial sample heating, unless special E-field free probes [17][18][19][20] or extensive sample cooling (which may cause temperature gradients in the sample) are used.…”

“…Experimental analysis of rCW C and state-of-the-art decoupling sequences addressing (a) broadbandedness with respect to rf offset and (b) variation of the rf amplitude as observed (peak height) for the 13 C α -spin of U-13 C,15 N-labeled glycine under conditions of 20 kHz sample spinning (2.5 mm rotor) on a Bruker Avance II 700 MHz NMR spectrometer. For direct comparison all decoupling sequences used 140 kHz rf field strength (for rCW C both for the CW and refocusing pulses; for the other sequences the pulse length and phase shift have been individually optimized).…”

Chapter 2. Solid‐State NMR in Drug Discovery and Development

“…In SSNMR applications of interest to pharmaceuticals, where rigid crystalline organic solids are often encountered, it is common to use high RF power levels of 100 kHz or more on the 1 H channel for TPPM or SPINAL decoupling. More recent developments include an improved super-cycled variant of the sweptfrequency TPPM sequence, 53 which has also been reported to show superior performance when fast MAS (n r ¼ 60 kHz) is concurrently employed. 54 The observation of 13 C spectra using a combination of CP, MAS and 1 H heteronuclear decoupling is one of the most basic and commonly executed experiments performed in drug discovery and development applications.…”

Two-Pulse Phase Modulation Based Decoupling Schemes for Removing Heteronuclear Spin Interactions in the NMR Spectroscopy of Isotropic Systems: An Analysis Using Experiments and Numerical Simulations

“…SW f -TPPM works admirably for heteronuclear dipolar decoupling in solid samples [5] and also in liquid crystals [7]. Currently, there exists a family of sequences in the literature [8][9][10][11][12][13][14] based on SW f -TPPM for heteronuclear dipolar decoupling in solids and liquid crystals.…”