scholarly journals Heteronuclear and homonuclear radio-frequency-driven recoupling

2021 ◽  
Vol 2 (1) ◽  
pp. 343-353
Author(s):  
Evgeny Nimerovsky ◽  
Kai Xue ◽  
Kumar Tekwani Movellan ◽  
Loren B. Andreas
Keyword(s):  
Radio Frequency ◽  
Numerical Simulations ◽  
Crucial Role ◽  
Pulse Sequence ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Dipolar Interactions ◽  
Phase Cycling ◽  
Angle Spinning

Abstract. The radio-frequency-driven recoupling (RFDR) pulse sequence is used in magic-angle spinning (MAS) NMR to recouple homonuclear dipolar interactions. Here we show simultaneous recoupling of both the heteronuclear and homonuclear dipolar interactions by applying RFDR pulses on two channels. We demonstrate the method, called HETeronuclear RFDR (HET-RFDR), on microcrystalline SH3 samples at 10 and 55.555 kHz MAS. Numerical simulations of both HET-RFDR and standard RFDR sequences allow for better understanding of the influence of offsets and paths of magnetization transfers for both HET-RFDR and RFDR experiments, as well as the crucial role of XY phase cycling.

scholarly journals Heteronuclear and Homonuclear Radio Frequency Driven Recoupling

2021 ◽  
Author(s):  
Evgeny Nimerovsky ◽  
Kai Xue ◽  
Kumar Tekwani Movellan ◽  
Loren B. Andreas
Keyword(s):  
Radio Frequency ◽  
Numerical Simulations ◽  
Crucial Role ◽  
Pulse Sequence ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Dipolar Interactions ◽  
Phase Cycling ◽  
Angle Spinning

Abstract. The Radio Frequency Driven Recoupling (RFDR) pulse sequence is used in magic-angle spinning (MAS) NMR to recouple homonuclear dipolar interactions. Here we show simultaneous recoupling of both the heteronuclear and homonuclear dipolar interactions by applying RFDR pulses on two channels. We demonstrate the method, called HETeronuclear RFDR (HET-RFDR) on microcrystalline SH3 samples at 10 kHz and 55.555 kHz MAS. Numerical simulations of both HET-RFDR and standard RFDR sequences allow better understanding of the influence of offsets, paths of magnetization transfers for both HET-RFDR and RFDR experiments as well as the crucial role of XY phase cycling.

Heteronuclear and Homonuclear Finite Pulse Radio Frequency Driven Recoupling

2020 ◽  
Author(s):  
Evgeny Nimerovsky ◽  
Kai Xue ◽  
Kumar Tekwani Movellan ◽  
Loren Andreas
Keyword(s):  
Radio Frequency ◽  
Solid State Nmr ◽  
Magnetization Transfer ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Phase Cycling ◽  
The Past ◽  
Pulse Radio ◽  
Dipolar Truncation ◽  
Angle Spinning

Abstract. Homonuclear finite-pulse radio frequency driven recoupling (fp-RFDR) has been broadly used in multi-dimensional magic-angle spinning (MAS) solid-state NMR experiments over the past 20 years. The theoretical and the simulated descriptions of this method were presented during that time, resulting in an understanding of the influence of chemical shift offset, finite pulse effects, and dipolar truncation. Here we present an operator analysis of both heteronuclear and homonuclear fp-RFDR. By numerical simulation, we show which operators are involved in the longitudinal exchange for both heteronuclear and the well-known homonuclear sequences. This results in a better understanding of the influence of phase cycling of the fp-RFDR pulses, which is typically a variant of XY cycling. We investigate the heteronuclear and homonuclear fp-RFDR signals and evolution of the operators through the fp-RFDR block. We show the convergence of the evolutions of the heteronuclear and homonuclear fp-RFDR signals at even numbers of rotor periods and completely different evolution between them. We demonstrate heteronuclear 1H- 13C and 1H-15N fp-RFDR magnetization transfer using a microcrystalline SH3 sample at 100 kHz MAS.

Improving selectivity by using a multipurpose cross polarization magic angle spinning NMR pulse sequence

1993 ◽  
Vol 283 (3) ◽  
pp. 1025-1031 ◽  
Author(s):  
Ivan Hoogmartens ◽  
Peter Adriaensens ◽  
Dirk Vanderzande ◽  
Jan Gelan
Keyword(s):  
Pulse Sequence ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Angle Spinning

scholarly journals TmDOTP : An NMR- based Thermometer for Magic Angle Spinning NMR Experiments

2019 ◽  
Author(s):  
Dongyu Zhang ◽  
Boris Itin ◽  
Ann E. McDermott
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Radio Frequency ◽  
Solid State Nmr ◽  
Lanthanide Complex ◽  
Magic Angle Spinning ◽  
Sample Temperature ◽  
Proton Spectrum ◽  
Magic Angle ◽  
Angle Spinning

AbstractSolid state NMR is a powerful tool to probe membrane protein structure and motions in native lipid structures. Sample heating, caused by magic angle spinning and radio frequency irradiation in solid state NMR, produces uncertainties in sample temperature and thermal broadening caused by temperature distributions, which can also lead to sample deterioration. To measure the sample temperature in real time, and to quantify thermal gradients and their dependence on radio frequency irradiation or spinning frequency, we use the chemical shift thermometer TmDOTP, a lanthanide complex. Compared to other NMR thermometers (e.g., the proton NMR signal of water), the proton spectrum of TmDOTP exhibits higher thermal sensitivity and resolution. In addition, the H6 proton in TmDOTP has a large chemical shift (−175 ppm at 275 K) and is well resolved from the rest of the proton spectrum. We identified two populations of TmDOTP, with differing temperatures and dependency on the radio frequency irradiation power, within proteoliposome samples. We interpret these populations as arising from the supernatant and the pellet, which is sedimented from the sample spinning. Our results indicate that TmDOTP is an excellent internal standard for monitoring temperatures of biophysically relevant samples without distorting their properties.

scholarly journals Optimizing nitroxide biradicals for cross-effect MAS-DNP: the role of g-tensors’ distance

2020 ◽  
Vol 22 (6) ◽  
pp. 3643-3652 ◽  
Author(s):  
Frédéric Mentink-Vigier
Keyword(s):  
Solid State ◽  
Dynamic Nuclear Polarization ◽  
Solid State Nmr ◽  
Nuclear Polarization ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Effect ◽  
Angle Spinning

Nitroxide biradicals are common polarizing agents used to enhance the sensitivity of solid-state NMR experiments via Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP).

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