JMR up to Volume 187, Issue 2, August 2007

Journal of Magnetic Resonance
Volume 187, Issue 2, August 2007, Pages 343-351
doi:10.1016/j.jmr.2007.05.020

Title: Use of SPAM and FAM pulses in high-resolution MAS NMR spectroscopy of quadrupolar nuclei

Thomas J. Ball and Stephen Wimperis
Department of Chemistry and WestCHEM, University of Glasgow, Glasgow G12 8QQ, UK
Received 15 March 2007; revised 18 May 2007. Available online 9 June 2007.

Abstract
The merits of SPAM and FAM pulses for enhancing the conversion of triple- to single-quantum coherences in the two-dimensional MQMAS experiment are compared using 87Rb (spin I = 3/2) and 27Al (I = 5/2) NMR of crystalline and amorphous materials. Although SPAM pulses are more easily optimized, our experiments and simulations suggest that FAM pulses yield greater signal intensity in all cases. In conclusion, we argue that, as originally suggested, SPAM and FAM pulses are best implemented in phase-modulated whole-echo MQMAS experiments and that the use of SPAM pulses to record separate echo and antiecho data sets, which are then combined, generally yields lower signal-to-noise ratios.

Keywords: NMR; Solid-state NMR; MAS NMR; Composite pulses; MQMAS; STMAS; FAM; SPAM

Journal of Magnetic Resonance
Vol: 187, Issue: 1, July, 2007

Title: First principles NMR calculations of phenylphosphinic acid C6H5HPO(OH): Assignments, orientation of tensors by local field experiments and effect of molecular motion
Authors: Gervais, C.a; Coelho, C.a; Azai¨s, T.a; Maquet, J.a; Laurent, G.a; Pourpoint, F.a; Bonhomme, C.a; Florian, P.b; Alonso, B.c; Guerrero, G.d; Mutin, P.H.d; Mauri, F.e
Keywords: Solid state NMR; 1H CSA; GIPAW calculations; Tensors

Abstract (English):
The complete set of NMR parameters for 17O enriched phenylphosphinic acid C6H5HP*O(*OH) is calculated from first principles by using the Gauge Including Projected Augmented Wave (GIPAW) approach [C.J. Pickard, F. Mauri, All-electron magnetic response with pseudopotentials: NMR chemical shifts, Phys. Rev. B 63 (2001) 245101/1–245101/13]. The analysis goes beyond the successful assignment of the spectra for all nuclei (1H, 13C, 17O, 31P), as: (i) the 1H CSA (chemical shift anisotropy) tensors (magnitude and orientation) have been interpreted in terms of H bonding and internuclear distances. (ii) CSA/dipolar local field correlation experiments have allowed the orientation of the direct P–H bond direction in the 31P CSA tensor to be determined. Experimental and calculated data were compared. (iii) The overestimation of the calculated 31P CSA has been explained by local molecular reorientation and confirmed by low temperature static 1H31P CP experiments.

Journal of Magnetic Resonance
Vol: 187 Issue: 1, July, 2007 pp: 19-26
DOI: 10.1016/j.jmr.2007.03.017

Title: matNMR: A flexible toolbox for processing, analyzing and visualizing magnetic resonance data in Matlab®

Jacco D. van Beek, Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland

Received 9 March 2007; revised 23 March 2007

Abstract
matNMR (matnmr.sourceforge.net) is a toolbox for processing, analyzing and visualizing magnetic-resonance data within the Matlab® environment ( www.mathworks.com ) that aims for control, flexibility and extendability. Processing can be done using either a graphical user interface or with command-line scripts, both of which allow user-defined processing or analysis functions to be incorporated at any time. The direct access to data points during processing, and the extensive library of mathematical and visualization routines provided by Matlab, afford the high degree of control and flexibility needed in modern magnetic-resonance research.
Keywords: Magnetic resonance; Processing toolbox; Matlab; Visualization; Data analysis.

Journal of Magnetic Resonance
Vol: 186 Issue: 2, June, 2007 pp: 220-227
DOI: 10.1016/j.jmr.2007.02.015

Title: Through-space R3 -HETCOR experiments between spin-1/2 and half-integer quadrupolar nuclei in solid-state NMR

J. Trebosc a, B. Hu a, J.P. Amoureux a, , Email Address, Z. Gan b
a UCCS, CNRS-8181, Université de Lille, FR-59652 Villeneuve d'Ascq, France
b National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL 32310, USA

Received 25 January 2007 Abstract
We present several new methods that allow to obtain through-space 2D HETCOR spectra between spin-1/2 and half-integer quadrupolar nuclei in the solid state. These methods use the rotary-resonance concept to create hetero-nuclear coherences through the dipolar interaction instead of scalar coupling into the HMQC and refocused INEPT experiments for spin n /2 (n > 1). In opposite to those based on the cross-polarization transfer to quadrupolar nuclei, the methods are very robust and easy to set-up.

Keywords: Solid-state NMR; Quadrupolar nuclei; HETCOR; Dipolar coupling; HMQC; R-INEPT.