Wednesday, December 28, 2005

Hiyam Journals

Chemistry - A European Journal

Volume 12, Issue 2, Pages 363-375

X-ray Diffraction and Solid-State NMR Studies of a Germanium Binuclear Complex

Luís Mafra, Filipe A. Almeida Paz, Dr. , Fa-Nian Shi, Dr., João Rocha, Prof., Tito Trindade, Dr. , Christian Fernandez, Prof., Anna Makal, Krzysztof Wozniak, Prof., Jacek Klinowski, Prof.


A compound formulated as (C4H12N2)[Ge2(pmida)2(OH)2]4 H2O (where pmida4-=N-(phosphonomethyl)iminodiacetate and C4H12N22+=piperazinedium cation), containing the anionic [Ge2(pmida)2(OH)2]2- complex, has been synthesised by the hydrothermal approach and its structure determined by single-crystal X-ray diffraction analysis. Several high-resolution solid-state magic-angle spinning (MAS) NMR techniques, in particular two-dimensional 1H-X(13C,31P) heteronuclear correlation (HETCOR) and 1H-1H homonuclear correlation (HOMCOR) experiments incorporating a frequency-switched Lee-Goldburg (FS-LG) decoupling scheme, have been employed for the first time in such a material. Using these tools in tandem affords an excellent general approach to study the structure of other inorganic-organic hybrids. We assigned the NMR resonances with the help of CH and PH internuclear distances obtained through systematic statistical analyses of the crystallographic data. The compound was further characterised by powder X-ray diffraction techniques, IR and Raman spectroscopy, and by elemental and thermal analyses (thermogravimetric analysis and differential scanning calorimetry).

Chemistry - A European Journal
Volume 12, Issue 1, Pages 159-168

An Investigation of Lanthanum Coordination Compounds by Using Solid-State 139La NMR Spectroscopy and Relativistic Density Functional Theory (p 159-168) Mathew J. Willans, Kirk W. Feindel, Kristopher J. Ooms, Roderick E. Wasylishen


Lanthanum-139 NMR spectra of stationary samples of several solid LaIII coordination compounds have been obtained at applied magnetic fields of 11.75 and 17.60 T. The breadth and shape of the 139La NMR spectra of the central transition are dominated by the interaction between the 139La nuclear quadrupole moment and the electric field gradient (EFG) at that nucleus; however, the influence of chemical-shift anisotropy on the NMR spectra is non-negligible for the majority of the compounds investigated. Analysis of the experimental NMR spectra reveals that the 139La quadrupolar coupling constants (CQ) range from 10.0 to 35.6 MHz, the spans of the chemical-shift tensor () range from 50 to 260 ppm, and the isotropic chemical shifts (iso) range from -80 to 178 ppm. In general, there is a correlation between the magnitudes of CQ and , and iso is shown to depend on the La coordination number. Magnetic-shielding tensors, calculated by using relativistic zeroth-order regular approximation density functional theory (ZORA-DFT) and incorporating scalar only or scalar plus spin-orbit relativistic effects, qualitatively reproduce the experimental chemical-shift tensors. In general, the inclusion of spin-orbit coupling yields results that are in better agreement with those from the experiment. The magnetic-shielding calculations and experimentally determined Euler angles can be used to predict the orientation of the chemical-shift and EFG tensors in the molecular frame. This study demonstrates that solid-state 139La NMR spectroscopy is a useful characterization method and can provide insight into the molecular structure of lanthanum coordination compounds.

Monday, December 26, 2005

CP/MAS article: CPL 2006, 417, 58-62.

A new technique for cross polarization in solid-state NMR compatible with high spinning frequencies and high magnetic fields
Chemical Physics Letters, Volume 417, Issues 1-3, 9 January 2006, Pages 58-62
Weng Kung Peng, Kazuyuki Takeda and Masahiro Kitagawa


The idea of integrated cross polarization which has been utilized for electron-to-nucleus polarization transfer is applied to nucleus-to-nucleus polarization transfer. Instead of using a Click to view the MathML source pulse followed by a Click to view the MathML source phase-shifted locking pulse like in the conventional cross polarization, irradiation with a single phase is applied together with adiabatic frequency sweep from far off-resonance toward on-resonance. This is capable of locking individual spin packets even in the presence of considerable spectral distribution and/or line broadening. Thus, this technique can provide efficient polarization transfer for spin species having large chemical shifts and experiments in high static fields.

Wednesday, December 21, 2005

K. Mueller, 27Al and 29Si NMR, J. Phys Chem B 2005, ASAP

Joel, 27Al and 29Si NMR

J. Phys. Chem. B, ASAP Article 10.1021/jp055401l S1089-5647(05)05401-5
Web Release Date: December 21, 2005
Solid-State NMR Identification and Quantification of Newly Formed Aluminosilicate Phases in Weathered Kaolinite Systems

Garry S. Crosson, Sunkyung Choi, Jon Chorover, Mary Kay Amistadi, Peggy A. O'Day, and Karl T. Mueller*

Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, Department of Soil, Water and Environmental Science, University of Arizona, Tucson, Arizona 85721, and School of Natural Sciences, University of California, Merced, California 95344

In Final Form: November 15, 2005


The weathering of a specimen kaolinite clay was studied over the course of 369 d via solid-state 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy and high-field 27Al MAS NMR. The chosen baseline solution conditions (0.05 mol kg-1 of Al, 2 mol kg-1 of Na+, 1 mol kg-1 of NO3-, 1 mol kg-1 of OH-, and pH ~13.8) approximate those of solutions leaking from waste tanks at the Hanford Site in Richland, WA. Nonradioactive Cs and Sr cations were added to this synthetic tank waste leachate (STWL) solution at concentrations of 10-3, 10-4, and 10-5 molal (m) to represent their radionuclide counterparts. The transformations of silicon- and aluminum-containing solid phase species were monitored quantitatively by using NMR spectroscopy, with the resulting spectra directly reporting the influence of the initial Cs and Sr on formation and transformation of the neo-formed solids. At the lowest concentration of Cs and Sr employed (10-5 m in each cation) peaks consistent with the formation of zeolite-like minerals were detected via 29Si and 27Al MAS NMR as early as 33 d. At concentrations of 10-3 m in each cation, new silicon species are not detected until 93 d, although neophases containing four-coordinate aluminum were detectable at earlier reaction times via 27Al MAS NMR. At the highest magnetic field strengths employed in this NMR study, deconvolutions of resonances detected in the tetrahedral region of the 27Al MAS spectra yielded multiple components, indicating the existence of at least four new aluminum-containing phases. Two of these phases are identified as sodalite and cancrinite through comparison with diffuse-reflectance infrared (DRIFT) spectra and powder X-ray diffraction (XRD) results, while a third phase may correlate with a previously detected aluminum-rich chabazite phase. All measurable solid reaction products have been quantified via their 27Al MAS resonances acquired at high magnetic field strengths (17.6 T), and the quantitative nature of the 27Al NMR data shows that cancrinite growth increases while sodalite reaches a steady state with respect to total aluminum in the solid phases. The data also relate the coupling of Cs sorption to the ripening of feldspathoid phases in this heterogeneous system as a function of time, and illustrate the important influence of co-contaminants on the environmental reaction kinetics studied here.

Monday, December 19, 2005

Latest online articles: Dec 19/05

December 19, 2005 - New articles

Cory, interesting 31P NMR
Chemical Communications, 2005, (Advance Article)
DOI: 10.1039/b513037a
No aromaticity of P64– observed via solid state 31P-NMR spectroscopy
Florian Kraus, Jörn Schmedt auf der Günne, Brian F. DiSalle and Nikolaus Korber
The solid state NMR spectra of the binary alkali hexaphosphides Rb4P6 and Cs4P6 unambiguously show the P64– anion not to be aromatic.

6Li NMR, spin-1 nuclei

Chem. Mater., ASAP Article 10.1021/cm0508773 S0897-4756(05)00877-X
Web Release Date: November 22, 2005

6Li NMR Studies of Cation Disorder and Transition Metal Ordering in Li[Ni1/3Mn1/3Co1/3]O2 Using Ultrafast Magic Angle Spinning

L. S. Cahill, S.-C. Yin, A. Samoson, I. Heinmaa, L. F. Nazar, and G. R. Goward*

Revised Manuscript Received October 13, 2005


Studies of Li[Ni1/3Mn1/3Co1/3]O2 prepared under six different conditions are compared using high-resolution solid-state 6Li NMR. Differing degrees of cation disorder are established via integration of the NMR resonances, and this quantification of cation disorder is compared with Rietveld refinements of powder X-ray and neutron diffraction studies. Chemical shift trends to high frequency with decreasing degrees of disorder are established among this family of samples and explained according to the orbital overlap experienced by Li nuclei in the two environments: within the lithium layers and exchanged with nickel into the transition metal layers. Finally, an interesting case of local transition metal charge ordering is observed. Three unique environments are described, which can be accounted for based on electroneutrality arguments, and the known clustering of Ni2+ and Mn4+. This effect has not been detected in these materials by other methods including neutron and X-ray diffraction. Thus, the local ordering, which is observed in the dominant NMR resonance of Li in its own layers is thought to be pervasive (affecting the majority of the NMR nuclei), but very local, so as to be seen only by techniques such as NMR which probe immediate neighborhoods.

Cory, 31P NMR
J. Phys. Chem. A, ASAP Article 10.1021/jp0555910 S1089-5639(05)05591-X
Web Release Date: December 3, 2005

A Theoretical Study of 31P NMR Chemical Shielding Models for Concentrated Phosphoric Acid Solution
D. B. Chesnut
P. M. Gross Chemical Laboratory, Duke University, Durham, North Carolina 27708
In Final Form: November 5, 2005

Calculations on the hydrates, dimer, and trimer of phosphoric acid were carried out in an effort to obtain a viable model of the phosphorus NMR chemical shielding in 85% phosphoric acid solution. The theoretical approaches used the gauge-including-atomic-orbital (GIAO) 6-311+G(nd,p) basis set at both scaled density functional theory (sB3LYP) and estimated infinite order Mller-Plesset (EMPI) approaches and with the aug-cc-pvtz basis in the sB3LYP approach. Shieldings and hydrogen bonding stabilization energies are similar in the three approaches and indicate that the faster sB3LYP/6-311+G(nd,p) approach can be used with larger systems. The changes in shielding compared to the isolated species are small and suggest that the undissociated acid dihydrate could serve as a model entity for modeling the phosphorus shielding in concentrated phosphoric acid solution.

Andy, Joel

J. Phys. Chem. B, ASAP Article 10.1021/jp055130e S1089-5647(05)05130-8
Web Release Date: December 14, 2005

Dynamics of p-Nitroaniline Molecules in Micoporous Aluminophosphate AlPO4-5 Studied by Solid-State NMR
Yoshihiko Komori and Shigenobu Hayashi*

Research Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan

In Final Form: November 7, 2005


Dynamics of deuterated p-nitroaniline (pNA-d) molecules in the micropores of AlPO4-5 has been investigated by means of solid-state NMR. The adsorbed amounts of pNA-d were 5.0 and 10.1 mass % of the total mass. We have measured 13C magic-angle-spinning (MAS) and 2H NMR spectra of the guest molecules and 31P and 27Al MAS NMR spectra of the host framework. The pNA-d molecules distribute rather inhomogeneously in the channel, and do not coordinate to Al strongly like H2O. The intermolecular hydrogen bonds are formed between a part of the guest molecules only when the loading level is high. The 2H NMR spectra are successfully analyzed, elucidating the orientation and the motion of the guest molecules. The molecular axis of pNA-d is inclined to the channel axis, and the molecular plane is perpendicular to the inner wall. The guest molecule jumps among 12 sites or 12 orientations. This motion is faster in the sample of 5.0 mass % than in the sample of 10.1 mass %, suggesting that the guest-guest interaction hinders the motion. The mean residence times of the molecules are estimated from the analysis of the 2H NMR spectra, which are affected by the size of the nanospace as well as the property of the adsorbed site.

J. Phys. Chem. B, ASAP Article 10.1021/jp054022p S1089-5647(05)04022-8
Web Release Date: December 15, 2005

31P NMR Chemical Shifts in Hypervalent Oxyphosphoranes and Polymeric Orthophosphates
Yong Zhang and Eric Oldfield*

Departments of Chemistry and Biophysics, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801

In Final Form: November 14, 2005


We report the first quantum chemical investigation of the solid- and solution-state 31P NMR chemical shifts in models for phosphoryl transfer enzyme reaction intermediates and in polymeric inorganic phosphates. The 31P NMR chemical shifts of five- and six-coordinate oxyphosphoranes containing a variety of substitutions at phosphorus, as well as four-coordinate polymeric orthophosphates and four-coordinate phosphonates, are predicted with a slope of 1.00 and an R2 = 0.993 (N = 34), corresponding to a 3.8 ppm (or 2.1%) error over the entire 178.3 ppm experimental chemical shift range, using Hartree-Fock methods. For the oxyphosphoranes, we used either experimental crystallographic structures or, when these were not available, fully geometry optimized molecular structures. For the four-coordinate phosphonates we used X-ray structures together with charge field perturbation, to represent lattice interactions. For the three-dimensional orthophosphates (BPO4, AlPO4, GaPO4), we again used X-ray structures, but for these inorganic systems we employed a self-consistent charge field perturbation approach on large clusters, to deduce peripheral atom charges. For pentaoxyphosphoranes, the solvent effect on 31P NMR chemical shieldings was found to be very small (<0.5 r2 =" 0.923)">

Cory, others doing EFG calculations

J. Phys. Chem. A, ASAP Article 10.1021/jp0554947 S1089-5639(05)05494-0
Web Release Date: December 17, 2005

Influence of N-H???O and C-H???O Hydrogen Bonds on the 17O NMR Tensors in Crystalline Uracil: Computational Study

Ramsey Ida, Maurice De Clerk, and Gang Wu*

Department of Chemistry, Queen's University, Kingston, Ontario, Canada K7L 3N6

In Final Form: November 14, 2005

We report a computational study for the 17O NMR tensors (electric field gradient and chemical shielding tensors) in crystalline uracil. We found that N-H???O and C-H???O hydrogen bonds around the uracil molecule in the crystal lattice have quite different influences on the 17O NMR tensors for the two C=O groups. The computed 17O NMR tensors on O4, which is involved in two strong N-H???O hydrogen bonds, show remarkable sensitivity toward the choice of cluster model, whereas the 17O NMR tensors on O2, which is involved in two weak C-H???O hydrogen bonds, show much smaller improvement when the cluster model includes the C-H???O hydrogen bonds. Our results demonstrate that it is important to have accurate hydrogen atom positions in the molecular models used for 17O NMR tensor calculations. In the absence of low-temperature neutron diffraction data, an effective way to generate reliable hydrogen atom positions in the molecular cluster model is to employ partial geometry optimization for hydrogen atom positions using a cluster model that includes all neighboring hydrogen-bonded molecules. Using an optimized seven-molecule model (a total of 84 atoms), we were able to reproduce the experimental 17O NMR tensors to a reasonably good degree of accuracy. However, we also found that the accuracy for the calculated 17O NMR tensors at O2 is not as good as that found for the corresponding tensors at O4. In particular, at the B3LYP/6-311++G(d,p) level of theory, the individual 17O chemical shielding tensor components differ by less than 10 and 30 ppm from the experimental values for O4 and O2, respectively. For the 17O quadrupole coupling constant, the calculated values differ by 0.30 and 0.87 MHz from the experimental values for O4 and O2, respectively.

Friday, December 16, 2005

Rob's journals - Dec. 2005 - Jan. 2006

Rob's journals - Dec. 2005 - Jan. 2006

Acc. Chem. Res. (ACS) - last issue - Volume 38 Issue 11 (November 15, 2005) Chem. Phys. Chem. (Elsevier) -
Volume 6, Issue 12 (December 9, 2005) Chemical Reviews (ACS) - last issue - Volume 105 Issue 12 (December 14, 2005) Chemical Society Reviews (RSC) - last issue - Dec 2005, Vol. 34, i12.
Concepts in NMR
(Wiley) - last issue - Volume 27A Issue 2 - November 2005 (55 - 123)
Faraday Disc.
(RSC) - last issue -
2005, 130, 3 J. Magn. Reson. (Elsevier)** - see articles below - Sept. 2005 - Jan. 2006 ( v.178, i. 1)
Magn. Reson. Chem. (Wiley) - up to Jan. 2006 issue
Progress in NMR (Elsevier)** - see articles below - Issue 47, Dec 15, 2005
Solid State NMR (Elsevier)** - Feb. 2006 last issue

CPC 6, 2005:
In Situ 1H NMR Study on the Trioctylphosphine Oxide Capping of Colloidal InP Nanocrystals (p 2578-2584) Zeger Hens, Iwan Moreels, Jose C. Martins

JMR 178, 2006:
EasySpin, a comprehensive software package for spectral simulation and analysis in EPR Stoll, Stefan; Schweiger, Arthur pp. 42-55

Sample patterning on NMR surface microcoils Ehrmann, K.; Gersbach, M.; Pascoal, P.; Vincent, F.; Massin, C.; Stamou, D.; Besse, P.-A.; Vogel, H.; et. al. pp. 96-105

Hadamard NMR spectroscopy in solids Ashida, Jun; Kupče, Ä'riks; Amoureux, Jean-Paul pp. 129-135

Chemical shift anisotropy amplification with high amplification factor and improved sensitivity Shao, Limin; Crockford, Charles; Titman, Jeremy J. pp. 155-161

JMR 177, 2005:
Rotor-synchronized acquisition of quadrupolar satellite-transition NMR spectra: practical aspects and double-quantum filtration Ashbrook, Sharon E.; Wimperis, Stephen pp. 44-55

Solid state 31P and 207Pb MAS NMR studies on polycrystalline O,O′-dialkyldithiophosphate lead(II) complexes Larsson, Anna-Carin; Ivanov, Alexander V.; Pike, Kevin J.; Forsling, Willis; Antzutkin, Oleg N. pp. 56-66

Fresco paintings studied by unilateral NMR Proietti, N.; Capitani, D.; Lamanna, R.; Presciutti, F.; Rossi, E.; Segre, A.L. pp. 111-117

Progress in NMR, 47, 2005:
Measuring heteronuclear dipolar couplings for I=1/2, S>1/2 spin pairs by REDOR and REAPDOR NMR : 1/2 spin pairs by REDOR and REAPDOR NMR" type="hidden"> Gullion, Terry; Vega, Alexander J. pp. 123-136

SSNMR, 28, 2005:
Multiple-magnetic field 139La NMR and density functional theory investigation of the solid lanthanum(III) halides 139La NMR and density functional theory investigation of the solid lanthanum(III) halides" type="hidden"> Ooms, Kristopher J.; Feindel, Kirk W.; Willans, Mathew J.; Wasylishen, Roderick E.; Hanna, John V.; et. al. pp. 125-134

93Nb NMR chemical shift scale for niobia systems 93Nb NMR chemical shift scale for niobia systems" type="hidden"> Lapina, Olga B.; Khabibulin, Dzhalil F.; Romanenko, Konstantin V.; Gan, Zhehong; Zuev, Mikhail G.; et. al. pp. 204-224

SSNMR, 29, 2006:
High-field QCPMG NMR of strontium nuclei in natural minerals
Bowers, Geoffrey M.; Lipton, Andrew S.; Mueller, Karl T. pp. 95-103

A combined Formula Not Shown RAPT and MQ-MAS NMR study of l-leucine
Prasad, Subramanian; Clark, Ted M.; Sharma, Ramesh; Kwak, Hyung-Tae; Grandinetti, Philip J.; et. al. pp. 119-124