Wednesday, May 12, 2010

Bryan's Journal Update, Part I

I know you've all been on the edge of your seats!


This may be useful for the purposes of CASTEP calculations. I think.

Chemical Physics Letters
Volume 484, Issues 4-6, 7 January 2010, Pages 374-379

Influence of plane wave cut-off on structural and electronic properties in Sn-BEA and Ti-BEA zeolite water molecule interaction

Bhakti S. Kulkarnia, Sailaja Krishnamurtyb and Sourav Pala,

a Physical Chemistry Division, National Chemical Laboratory, Pune 411 008, India

b Electrochemical Research Institute (CECRI), Karaikudi 630 006, India

Received 12 October 2009;
accepted 21 November 2009.
Available online 26 November 2009.


Periodic systems are best described by the pseudo-potential methods. However, the accuracy of its description depends on the cut-off of plane wave basis. This is much more critical in the case of weak interactions, where a clear understanding on the influence of plane wave cut-off on the structural and electronic properties is not readily available in the literature. In the present work, we have taken a metal substituted beta zeolite–H2O complex for understanding this objective. Our studies show that while a lower cut-off of 500 eV is sufficient for the convergence of the structural parameters, description of energy-dependent properties necessitates a high cut-off value.


Chemical Physics Letters
Volume 485, Issues 1-3, 18 January 2010, Pages 217-220

NMR spectroscopy in the milli-Tesla regime: Measurement of 1H chemical-shift differences below the line width

Stephan Appelta, , Stefan Glögglerb, Friedrich W. Häsinga, Ulrich Sielinga, Ali Gordji Nejada and Bernhard Blümichb

a Zentralinstitut für Elektronik, Forschungszentrum Jülich, D-52425 Jülich, Germany

b Institut für Technische Chemie und Makromolekulare Chemie, RWTH Aachen University, D-52056 Aachen, Germany

Received 16 October 2009;
accepted 29 November 2009.
Available online 1 December 2009.


NMR spectroscopy for chemical analysis at high field employs precision measurements of resonance frequencies governed by chemical shift and nuclear spin interactions. At low field and in the absence of hetero-nuclear J-couplings the natural line width limits the chemical shift measurements. We have performed chemical-shift resolved proton NMR spectra in the milli-Tesla regime, and found that in the presence of hetero-nuclear J-coupling, proton chemical-shift differences smaller than the line width can be measured down to nuclear Larmor frequencies of 41 kHz. The measurement of J-couplings and chemical shifts with simple NMR devices operating in the milli-Tesla regime may develop as an attractive tool for chemical analysis.


Chemical Physics Letters
Volume 485, Issues 4-6, 26 January 2010, Pages 275-280

Proton micro-magic-angle-spinning NMR spectroscopy of nanoliter samples

Andreas Brinkmanna, b, , Suresh Kumar Vasaa, Hans Janssena and Arno P.M. Kentgensa, ,

a Physical Chemistry/Solid State NMR, Institute for Molecules and Materials, Radboud University Nijmegen, P.O. Box 9010, 6500 GL Nijmegen, The Netherlands

b Steacie Institute for Molecular Sciences, National Research Council, 1200 Montreal Road, M-40 Ottawa, Ontario, Canada K1A 0R6

Received 22 October 2009;
accepted 16 December 2009.
Available online 23 December 2009.


We present our recent progress in the development of micro-magic-angle-spinning solenoid-based probeheads for the application in high-resolution 1H solid-state NMR of nanoliter sample volumes. The use of fused-silica capillaries as sample holders results in spectra without any 1H background signal. It is possible to obtain 1H spectra of 40–80 nl samples in a few scans. We obtained high-resolution 1H spectra employing different homonuclear decoupling sequences on powdered samples of l-alanine, the tripeptide AGG, and a single crystal of l-tyrosine·HCl. In addition, we recorded high-resolution two-dimensional proton-detected 1H–13C heteronuclear correlation spectra of [U-13C3, 15N]-l-alanine and AGG with natural abundant isotope distribution.


Chemical Physics Letters
Volume 485, Issues 4-6, 26 January 2010, Pages 335-342

NMR polarization transfer by second-order resonant recoupling: RESORT

Ingo Scholza, Beat H. Meiera and Matthias Ernst, a,

a ETH Zurich, Physical Chemistry, 8093 Zurich, Switzerland

Received 13 November 2009;
accepted 15 December 2009.
Available online 22 December 2009.


We describe a resonant second-order dipolar recoupling condition for magic-angle spinning (MAS) solid-state NMR where the active spins are irradiated by continuous-wave irradiation and the passive spins by a phase-alternating sequence. The phase-modulation frequency is matched to an integer multiple of the MAS frequency to produce a second-order homonuclear dipolar coupling Hamiltonian that promotes broadband homonuclear zero-quantum polarization transfer on the spin-locked active spins. The recoupling sequence is based on second-order cross terms between two heteronuclear dipolar couplings. Similarities and differences to the proton-assisted recoupling sequence are discussed.

Everyone loves 3H NMR!

Chemical Physics Letters
Volume 486, Issues 1-3, 5 February 2010, Pages 21-26

3H NMR of the tritiated isotopologues of methane in nematic liquid-crystal solvents
Dedicated to the memory of Annalaura Segre (deceased 25 April 2008) and Jaap G. Snijders (deceased 13 August 2004).

E. Elliott Burnella, Cornelis A. de Langeb, , Donatella Capitanic, Giancarlo Angelinic and Ornella Ursinic

a Chemistry Department, University of British Columbia, 2036 Main Mall, Vancouver (BC), Canada V6T 1Z1

b Atomic, Molecular and Laser Physics, Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands

c Chemical Methodologies Institute, Consiglio Nazionale delle Ricerche, Area della Ricerca di Roma, C.P. 10 00016 Monterotondo Staz. (RM), Italy

Received 18 November 2009;
accepted 29 December 2009.
Available online 4 January 2010.


The NMR spectra of the tritiated isotopologues of methane dissolved in several nematic liquid-crystalline solvents are measured. The spectral parameters obtained agree extremely well with those predicted from earlier NMR studies of the deuterated isotopologues, providing excellent confirmation of the theory for vibration–reorientation interaction developed earlier.


Chemical Physics Letters
Volume 487, Issues 4-6, 5 March 2010, Pages 232-236

Solid-state 95Mo NMR of mixed-valence polyoxomolybdates (V, VI) with localized or delocalized d1 electrons

Takahiro Iijimaa, Toshihiro Yamaseb, Masataka Tanshoc, Tadashi Shimizuc and Katsuyuki Nishimuraa, ,

a Institute for Molecular Science, Okazaki 444-8585, Japan

b Tokyo Institute of Technology, Nagatsuta, Yokohama 226-8503, Japan

c National Institute for Materials Science, Tsukuba 305-0003, Japan

Received 23 October 2009;
accepted 19 January 2010.
Available online 25 January 2010.


We report solid-state 95Mo NMR of MoV, MoV,VI and MoVI species in mixed-valence polyoxomolybdates (V, VI) with localized or delocalized d1 electrons. Parameters about chemical shift and quadrupole interactions of 95Mo in diamagnetic crystals of View the MathML source with localized electrons and View the MathML source with delocalized ones were obtained by simulation of magic-angle-spinning (MAS) 95Mo NMR spectra. The isotropic and anisotropic chemical shifts of sites of MoV in 1 and MoV, VI in 2, respectively, exhibited absolute values quite larger than those of other MoVI sites, which is examined by quantum chemical calculations.


Chemical Physics Letters
Volume 487, Issues 4-6, 5 March 2010, Pages 285-290

Oxygen coordination of aluminum cations in dehydrated AlPW12O40 investigated by solid-state NMR spectroscopy

Arne Bressela, Jörg Freya, Urszula Filekb, Bogdan Sulikowskib, Dieter Freudec and Michael Hungera

a Institute of Chemical Technology, University of Stuttgart, Stuttgart, Germany

b Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Kraków, Poland

c Institute of Experimental Physics, University of Leipzig, Leipzig, Germany

Received 4 December 2009;
accepted 20 January 2010.
Available online 25 January 2010.


Dehydrated aluminumdodecatungstophosphate (AlPW12O40) was investigated by 27Al MAS NMR spectroscopy in magnetic fields of 9.4 and 17.6 T. Two kinds of octahedrally coordinated (δ27Al = 1–2 ppm, CQ = 2.4–2.5 MHz, and δ27Al = 4–6 ppm, CQ = 6.0–6.5 MHz), two kinds of penta-coordinated (δ27Al = 24–30 ppm, CQ = 7.0–7.3 MHz, and δ27Al = 44 ppm, CQ = 7.5–8.7 MHz), and a small amount of tetrahedrally coordinated aluminum cations (δ27Al = 65 ppm, CQ = 8.2–8.5 MHz) were found. Comparison with 1H MAS NMR spectroscopic studies indicates that the dehydroxylation of aluminum OH groups (δ1H = 4.2 ppm and 5.6 ppm) at temperatures of 473 and 573 K is accompanied by a partially irreversible change of the oxygen coordination of aluminum cations.


Chemical Physics Letters
Volume 488, Issues 1-3, 12 March 2010, Pages 10-16

Broadband magnetization transfer using moderate radio-frequency fields for NMR with very high static fields and spinning speeds

Markus Weingartha, Geoffrey Bodenhausena, b and Piotr Tekelya

a Département de chimie, associé au CNRS, Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris, France

b Institut des Sciences et Ingénierie Chimiques, BCH, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland

Received 4 January 2010;
accepted 29 January 2010.
Available online 4 February 2010.


We introduce a new dipolar recoupling scheme, dubbed PARIS-xy (phase-alternated recoupling irradiation scheme using orthogonal radio-frequency phases), to promote efficient broadband magnetization exchange between 13C nuclei using moderate radio-frequency amplitudes at very high magnetic field strengths and spinning speeds. Experimental observations for a wide range of spinning frequencies 30 less-than-or-equals, slant νrot less-than-or-equals, slant 60 kHz and magnetic field strengths (B0 = 9.4, 17.6 and 21.2 T) are backed up by numerical simulations.

A solid-state NMR scheme dubbed PARIS-xy affords efficient low-power recoupling of dipolar interactions between nuclei such as carbon-13 over a wide range of isotropic chemical shifts. The scheme is suitable for very high magnetic fields up to 21.2 T (900 MHz) and spinning speeds up to 60 kHz.


Chemical Physics Letters
Volume 488, Issues 4-6, 22 March 2010, Pages 168-172

DFT study of possible lattice defects in methane-hydrate and their appearance in 13C NMR spectra

Péter Terleczkya and László Nyulászi

a Budapest University of Technology and Economics, Department of Inorganic and Analytical Chemistry, H-1521 Szt Gellért tér 4, Budapest, Hungary

Received 14 December 2009;
accepted 9 February 2010.
Available online 12 February 2010.


The effect of the possible cell defects in the methane-hydrate crystal on the chemical shift of the carbon core has been investigated by DFT calculations. The clathrate structure was modeled as a water monolayer, in mono and bicavital clusters. The results show that the radius of the clathrate cell correlates with the chemical shielding of the carbon core. The calculated chemical shifts for the most stable clusters are in good agreement with the observed NMR signals supporting the previous spectral assignment. The occupancy of a neighbouring cell in a bicavital cluster has a small effect on the calculated NMR shift.


Chemical Physics Letters
Volume 489, Issues 1-3, 1 April 2010, Pages 35-38

A theoretical study of the stationary structures of the methane surface with special emphasis on NMR properties

Ibon Alkorta and José Elgueroa

a Instituto de Química Médica (CSIC), Juan de la Cierva, 3, E-28006 Madrid, Spain

Received 22 January 2010;
accepted 18 February 2010.
Available online 21 February 2010.


The seven stationary points of the methane hypersurface were first explored concerning geometries and energies to check previous data. On these geometries, absolute 1H and 13C NMR shieldings as well as 1J(CH) and 2J(HH) coupling constants were calculated. The results show important variations in the NMR parameters depending on the stationary point considered. Relationships have been found between the 1H and 13C shieldings and between these NMR parameters and the relative energy of the different species.


Chemical Physics Letters
Volume 489, Issues 1-3, 1 April 2010, Pages 107-112

1H NMR noise measurements in hyperpolarized liquid samples

Patrick Giraudeaua, 1, Norbert Müllerb, Alexej Jerschowc and Lucio Frydmana

a Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel

b Institute of Organic Chemistry, Johannes Kepler University, Altenbergerstraße 69, A-4040 Linz, Austria

c Chemistry Department, New York University, New York, NY 10003, United States

Received 31 August 2009;
accepted 9 February 2010.
Available online 12 February 2010.


Noise measurements of nuclear spin systems using a tuned circuit can reveal the signatures of two different phenomena: Thermal circuit noise absorbed by the spin system, and nuclear spin-noise leading to tiny fluctuating magnetization components. Polarization enhancement can increase the observed noise amplitudes due to an enlarged coupling with the reception circuit. In this work we explore the detection of noise in 1H NMR of liquid water samples whose spin alignment is enhanced via ex situ dynamic nuclear polarization. A number of ancillary phenomena related to this kind of experiments are also documented.


Chemical Physics Letters
Volume 489, Issues 4-6, 9 April 2010, Pages 248-253

Characterization of the 19F chemical shielding tensor using cross-correlated spin relaxation measurements and quantum chemical calculations

S. Begam Elavarasia and Kavita Doraib

a Department of Physics, Indian Institute of Technology-Madras, Chennai 600 036, India

b Department of Physics, Indian Institute of Science Education and Research (IISER) Mohali, Chandigarh 160 019, India

Received 14 January 2010;
accepted 28 February 2010.
Available online 3 March 2010.


The 19F chemical shift anisotropy (CSA) tensor is an indispensable structure estimation tool in the NMR investigations of flourinated biomolecules. This work focuses on the characterization of the 19F CSA tensor in small molecules, through the combined use of quantum chemical methods and liquid-state NMR cross-correlated spin relaxation experiments. The effect of different basis sets and quantum computational methods on the magnitude and orientation of the 19F CSA tensor are discussed. The results from ab initio methods and the liquid-state relaxation experiments match well and are comparable to values of the CSA tensor obtained from previous solid-state studies and from theoretical investigations of similar molecules.


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