Friday, July 20, 2007

Hiyam Journal Update

J. Am. Chem. Soc., 129 (21), 6704 -6705, 2007.

Ultrahigh-Field Solid-State 59Co NMR Studies of Co(C2B9H11)2- and Co(C5H5)2+ Salts

Kristopher J. Ooms, Victor V. Terskikh, and Roderick E. Wasylishen*

Cobalt-59 NMR spectra of stationary powder samples of salts containing Co(C2B9H11)2- and Co(C5H5)2+ have been acquired at 21.14 T using single-echo stepped-frequency experiments. The resulting central transition, mI = 1/2 mI = -1/2, line shapes span more than 2.0 MHz and are dominated by the second-order quadrupolar interaction. Analysis of the spectra leads to CQ values of ca. 163 MHz for both ions, among the largest 59Co CQ values reported. In addition, 59Co chemical shift anisotropies are significant for Co(C2B9H11)2- and Co(C5H5)2+, with values of 4500-4700 and 5650 ppm, respectively. Isotropic 59Co chemical shifts for the cobalticarborane anion are unavailable from NMR measurements of solution samples, probably because of the extremely short relaxation times anticipated for this complex.

Thursday, July 19, 2007

JMR up to Volume 187, Issue 2, August 2007

Journal of Magnetic Resonance
Volume 187, Issue 2, August 2007, Pages 343-351

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.

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

matNMR ( is a toolbox for processing, analyzing and visualizing magnetic-resonance data within the Matlab® environment ( ) 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.

Thursday, July 12, 2007

Inorganic Chemistry - up to Issue 14 (July 2007)

Kuhn, A.; Azcondo, M. T.; Amador, U.; Boulahya, K.; Sobrados, I.; Sanz, J.; Garcia-Alvarado, F.
"Structural Characterization and NMR Study of NaNbWO6 and Its Proton-Exchanged Derivatives." Inorg. Chem. 2007, 46(13), 5390-5397.

Abstract: The structural characterization of NaNbWO6, prepared by the ceramic route, has been performed. Electron diffraction has shown the presence of two related phases in a 1:1 ratio, whose lattice parameters correspond to those of the well-known tetragonal tungsten bronzes (TTB) and those of a monoclinically distorted phase. In addition to basic unit cells, the morphology of the two phases has been found to be similar, but they present a slight difference in the W/Nb ratio. 1H and 23Na magic-angle spinning nuclear magnetic resonance (MAS-NMR) spectra of NaNbWO6 and its proton-exchanged derivatives have been interpreted on the basis of the ideal TTB structure. The average structure and the morphology remain unchanged in Na1 - xHxNbWO6 derivatives. 1H and 23Na MAS-NMR spectroscopies have been used to monitor changes produced during exchange processes. It has been shown that the exchange of Na ions is mainly produced, but not exclusively, at tetragonal channels. However, a large amount of Na ions at the pentagonal channels do not exchange with protons, suggesting that these ions are needed to stabilize the TTB-like structure. A tentative distribution of sodium ions in the most-exchanged oxide, deduced from NMR results, ~(Na0.46)p(Na0.08)sH0.46NbWO6, has been proposed. NMR spectra of Na1 - xHxNbWO6 indicate that two different OH groups are formed upon exchanging. The study of samples hydrated with D2O allowed us to conclude that deuterons of adsorbed water exchange with protons of the two OH groups. The proton-deuteron exchange is slow at room temperature but is strongly enhanced at 90 C. This observation relates to the proton conductivity displayed by exchanged products under a humid atmosphere.

Solid-State NMR, up to Issue 4 (July 2007)

Solid-State NMR

Indirect covariance NMR spectroscopy of through-bond homo-nuclear correlations for quadrupolar nuclei in solids under high-resolution -

Bingwen Hu, Jean-Paul Amoureux and Julien Trebosc
UCCS, CNRS-8181, Lille University, FR-59652 Villeneuve d'Ascq, France
Received 20 November 2006; revised 26 February 2007. Available online 1 April 2007.


Indirect covariance NMR spectroscopy is demonstrated in solids, and we show that it can be used to obtain through-bond 2D homo-nuclear correlation spectra for quadrupolar nuclei under high-resolution. These spectra, generated with indirect covariance from a hetero-nuclear correlation spectrum, are equivalent to those recorded with the through-bond homo-nuclear hetero-nuclear single-quantum correlation (H-HSQC) method very recently proposed. However, the indirect covariance method can save a lot of experiment time, compared to the H-HSQC experiments, which allows introducing a high-resolution quadrupolar filter, thus providing a much better resolution, even on medium-field spectrometers. The covariance concept can be used to generate many different ‘indirectly-detected' high-resolution homo-nuclear correlation spectra with through-space or through-bond correlations for spin Click to view the MathML source or quadrupolar nuclei. We also propose a simple method that decreases the noise in all (direct or indirect) covariance methods.

Keywords: Indirect-covariance; GEN2D; H-HSQC experiment; J-coupling; MQ-HETCOR; ST-HETCOR; MQ-HOMCOR; ST-HOMCOR


A 27Al MAS NMR study of a sol–gel produced alumina: Identification of the NMR parameters of the theta-Al2O3 transition alumina phase -

L.A. O'Dell, S.L.P. Savin, A.V. Chadwick and M.E. Smith
Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
School of Physical Sciences, University of Kent, Canterbury, Kent, CT2 7NH, UK
Received 29 December 2006; revised 6 April 2007. Available online 13 May 2007.


27Al MAS NMR has been used to study a sol–gel prepared alumina annealed at various temperatures. Two-field simulation of the sample heated to 1200 °C confirmed the presence of corundum, as suggested by XRD, and also the presence of nanocrystalline ?-Al2O3. 27Al MAS NMR chemical shifts, quadrupolar coupling constants and asymmetry parameters are reported for the tetrahedral and octahedral aluminium sites within ?-Al2O3.

Keywords: 27Al MAS NMR; theta-alumina; NMR interaction parameters


Phosphorus-31 spin–lattice NMR relaxation in bone apatite and its mineral standards -

Agnieszka Kaflak and Waclaw
Medical University of Warsaw, Faculty of Pharmacy, Department of Inorganic and Analytical Chemistry, ul. Banacha 1, 02-097 Warszawa, Poland
Received 9 February 2007; revised 25 April 2007. Available online 16 May 2007.


Phosphorus-31 spin–lattice relaxation, both in the laboratory (B0=4.7 T) and rotating frame (B1=2.2 mT), was studied in the following samples: mineral of whole human bone (samples B1–B6), apatite prepared from bone (BHA), natural brushite (BRU), synthetic hydroxyapatite hydrated (HAh) and calcined (HAc), and synthetic carbonatoapatite of type B (CHA-B) with 9 wt% of CO32-. The T1P relaxation time was determined directly using the saturation recovery technique, while the Click to view the MathML source relaxation time was measured via 1H?31P CP by incrementing the 31P spin-lock. In order to avoid an effect of magic-angle spinning (MAS) on CP and relaxation, the experiments were carried out on static samples. The 31P spin–lattice relaxation was discussed for trabecular and cortical bone tissue from adult subjects in comparison to the synthetic mineral standards. None of the reference materials has matched accurately the relaxation behaviour of the bone mineral.

The most striking differences between the examined substances were observed for T1P, which for human bone was sample dependent and appeared in the range 55–100 s, while for HAh, HAc, and CHA-B was 7.2, 10.0, and 25.8 s, respectively. Possible reasons of so large relaxation diversity were discussed. It has been suggested that T1P of apatites is to some extent dependent on the concentration of the structural hydroxyl groups, and this in turn is controlled by the material crystallinity. It was also found that T1P decreased on hydration by ca. 30%.

Keywords: Bone; Mineral; Apatite; 31P NMR; Cross-polarization; Relaxation


Letter to the Editor: Two-dimensional 11B–11B exchange NMR study in mesoporous boron carbon nitride at 21.8 T -

Miwa Murakami, Tadashi Shimizu, Masataka Tansho, Ajayan Vinu, Katsuhiko Ariga, Toshiyuki Mori and K. Takegoshi
National Institute for Materials Science, 3-13 Sakura, Tsukuba, Ibaraki 305-0003, Japan
National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan

Tuesday, July 10, 2007

CPL Update

Single-scan 2D NMR spectroscopy on a 25 T bitter magnet
vol.442, iss 4-6, Pages 478-482
Boaz Shapira, Kiran Shetty, William W. Brey, Zhehong Gan and Lucio Frydman

2D NMR relies on monitoring systematic changes in the phases incurred by spin coherences as a function of an encoding time t1, whose value changes over the course of independent experiments. The intrinsic multi-scan nature of such protocols implies that resistive and/or hybrid magnets, capable of delivering the highest magnetic field strengths but possessing poor temporal stabilities, become unsuitable for 2D NMR acquisitions. It is here shown with a series of homo- and hetero-nuclear examples that such limitations can be bypassed using recently proposed 2D ‘ultrafast’ acquisition schemes, which correlate interactions along all spectral dimensions within a single-scan.