scholarly journals 7Li Solid State NMR Study of a TMEDA Complex of Trimethylsilylcyclopentadienyllithium

1993 ◽  
Vol 48 (11) ◽  
pp. 1555-1557 ◽  
Author(s):  
Tanja Pietraß ◽  
Paul K. Burkert
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Quadrupole Coupling Constant ◽  
Structural Features ◽  
Coupling Constant ◽  
X Ray ◽  
Nmr Study ◽  
Quadrupole Coupling ◽  
Increasing Temperature

7Li solid state NMR spectroscopy of Ν,Ν,N′,N′-tetramethylethylenediamine-trimethylsilylcyclopentadienyllithium yielded an unusually large quadrupole coupling constant, that decreases with increasing temperature (188-165 kHz in the temperature range 210-335 K). Structural features, known from the X-ray analysis, are compared with the NMR results.

Solid-state 25Mg NMR, X-ray crystallographic, and quantum mechanical study of bis(pyridine)-(5,10,15,20-tetraphenyl porphyrinato)magnesium(II)

2003 ◽  
Vol 81 (4) ◽  
pp. 275-283 ◽  
Author(s):  
Gang Wu ◽  
Alan Wong ◽  
Suning Wang
Keyword(s):  
Solid State ◽  
Bond Distance ◽  
Quadrupole Coupling Constant ◽  
Basis Set ◽  
Quantum Mechanical ◽  
Chemical Calculation ◽  
Porphyrin Ring ◽  
Coupling Constant ◽  
X Ray ◽  
Quadrupole Coupling

We report solid-state 25Mg NMR, X-ray crystallographic, and quantum-mechanical calculation results for bis(pyridine)(5,10,15,20-tetraphenylporphyrinato)magnesium(II), Mg(TPP)·Py2. Mg(TPP)·Py2 crystallizes in the triclinic form, in the space group P[Formula: see text]. The unit cell parameters are: a = 9.6139(13) Å, b = 11.0096(16) Å, c = 11.8656(15) Å; α = 102.063(3)°, β = 103.785(3)°, γ = 114.043(2)°; Z = 1. The Mg(II) ion is coordinated to four nitrogen atoms from the porphyrin ring and two nitrogen atoms from the axial pyridine ligands, forming a regular octahedron. The 25Mg quadrupole coupling constant (CQ) is 15.32 ± 0.02 MHz, which represents the largest value so far observed for 25Mg nuclei. The electric field gradient tensor at the Mg site is axially symmetric, ηQ = 0.00 ± 0.05. The 25Mg chemical shielding anisotropy is too small to be accurately determined. Quantum-mechanical calculations using a 6–31G(d) basis set reproduce reasonably well the observed 25Mg NMR data for Mg(TPP)·Py2. The calculations also suggest that the span of the 25Mg chemical shift tensor is less than 50 ppm. Using a theoretical approach, we also investigate the dependence of the 25Mg quadrupole coupling constant on the Mg—Nax bond distance. The calculation suggests that the 25Mg quadrupole coupling constant for an Mg(II) ion at the center of a porphyrin ring without axial ligands is approximately 22 MHz, which may be treated as an upper limit of the 25Mg quadrupole coupling constant for all Mg–porphyrin complexes.Key words: 25Mg NMR, crystal structure, quantum chemical calculation, quadrupole parameter, tetraphenylporphyrin.

7Li-Solid-State-NMR of [Li(N,N,N',N'-Tetramethylethylenediamine)] CLO4 and [Li (N,N,N', N'-Tetramethylethylenediamine)2] Al(CH3)4

1992 ◽  
Vol 47 (1-2) ◽  
pp. 117-119 ◽  
Author(s):  
Tanja Pietraß ◽  
Paul K. Burkert ◽  
Hans H. Karsch
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Quadrupole Coupling Constant ◽  
Positive Temperature ◽  
Coupling Constant ◽  
Axially Symmetric ◽  
Temperature Range ◽  
Central Transition ◽  
Quadrupole Coupling ◽  
Motional Narrowing

Abstract The temperature dependent 7Li-solid-state-NMR spectra of the two compounds [Li(N,N,N',N'- tetramethylethylenediamine)]ClO4 and [Li(N,N,N\N tetramethylethylenediamine)2]Al(CH3)4 are presented. Both compounds were investigated in the temperature range 160 K ≦ T ≦ 360 K. Above room temperature, the spectra for the tetramethylaluminate show the typical line shape for a first-order quadrupolar-disturbed central transition with an axially symmetric asymmetry parameter and a slightly positive temperature dependence of the quadrupole coupling constant. The mean temperature coefficient ά = + 9 • 10-4 K -1 . The quadrupole coupling constant is in the range of 36-39 kHz. In the Temperature range 240 K ≦ T ≦ 275 K the quadrupolar splitting cannot be resolved. Below 240 K the quadrupole coupling constant is about 100 kHz. Contrarily, in the Perchlorate the quadrupole coupling constant is 75 kHz and is temperature independent. With increasing temperature the satellites lower in intensity and the central transition undergoes motional narrowing

The Structure of Glasses Studied by MAS-NMR Spectroscopy of Quadrupolar Nuclei

1996 ◽  
Vol 51 (5-6) ◽  
pp. 585-590 ◽  
Author(s):  
W. Müller-Warmuth
Keyword(s):  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Quadrupole Coupling Constant ◽  
Oxide Glass ◽  
Ternary Oxide ◽  
Quadrupolar Nuclei ◽  
Coupling Constant ◽  
Structure Of Glasses ◽  
Quadrupole Coupling ◽  
Satellite Transition

High-resolution solid state NMR spectroscopy of quadrupolar nuclei (preferentially27Al) has been employed to study the microstructure of glasses. Importance has been attached tothe extraction of the fundamental NMR parameters like chemical shift, quadrupole coupling constantetc., from the spectra, first of all by applying satellite transition spectroscopy. Exemplary resultsare represented for ternary oxide glass systems such as K2O-Al2O3-SiO2, B2O3-Al2O3-P2O5, Na2O-B2O3-SiO2 and Na2O-B2O3-Al2O3.

scholarly journals A New Methodological Approach to Correlate Protective and Microscopic Properties by Soft X-ray Microscopy and Solid State NMR Spectroscopy: The Case of Cusa’s Stone

2021 ◽  
Vol 11 (13) ◽  
pp. 5767
Author(s):  
Veronica Ciaramitaro ◽  
Alberto Spinella ◽  
Francesco Armetta ◽  
Roberto Scaffaro ◽  
Emmanuel Fortunato Gulino ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Methodological Approach ◽  
Polymer Chains ◽  
General Question ◽  
Protective Agent ◽  
Vapour Permeability ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Hydrophobic treatment is one of the most important interventions usually carried out for the conservation of stone artefacts and monuments. The study here reported aims to answer a general question about how two polymers confer different protective performance. Two fluorinated-based polymer formulates applied on samples of Cusa’s stone confer a different level of water repellence and water vapour permeability. The observed protection action is here explained on the basis of chemico-physical interactions. The distribution of the polymer in the pore network was investigated using scanning electron microscopy and X-ray microscopy. The interactions between the stone substrate and the protective agents were investigated by means of solid state NMR spectroscopy. The ss-NMR findings reveal no significant changes in the chemical neighbourhood of the observed nuclei of each protective agent when applied onto the stone surface and provide information on the changes in the organization and dynamics of the studied systems, as well as on the mobility of polymer chains. This allowed us to explain the different macroscopic behaviours provided by each protective agent to the stone substrate.

scholarly journals Synthesis, characterization and modeling of self-assembled porphyrin nanorods

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1346-1354 ◽  
Author(s):  
Danielle Laurencin ◽  
Pascal G. Yot ◽  
Christel Gervais ◽  
Yannick Guari ◽  
Sébastien Clément ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Dft Calculations ◽  
Powder Diffraction ◽  
Solid State Nmr ◽  
Molecular Level ◽  
Ion Association ◽  
Free Base ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

Porphyrin nanorods were prepared by ion-association between free-base meso 5,10,15,20-tetrakis-(4-[Formula: see text]-methylpyridinium)porphyrin cations and tetraphenylborate anions. The nanorods have variable lengths (up to a few micrometers long) and diameters ([Formula: see text]50–500 nm). Their structure at the molecular level was elucidated by combining multinuclear solid state NMR spectroscopy, synchrotron X-ray powder diffraction and DFT calculations.

Investigating Sorption on Iron−Oxyhydroxide Soil Minerals by Solid-State NMR Spectroscopy:  A6Li MAS NMR Study of Adsorption and Absorption on Goethite

2005 ◽  
Vol 109 (39) ◽  
pp. 18310-18315 ◽  
Author(s):  
Ulla Gro Nielsen ◽  
Younkee Paik ◽  
Keinia Julmis ◽  
Martin A. A. Schoonen ◽  
Richard J. Reeder ◽  
...  
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Mas Nmr ◽  
Iron Oxyhydroxide ◽  
Soil Minerals ◽  
Solid State Nmr Spectroscopy ◽  
Nmr Study

scholarly journals Characterization and Quantitation of Clarithromycin Polymorphs by Powder X-Ray Diffractometry and Solid-State NMR Spectroscopy

2002 ◽  
Vol 50 (8) ◽  
pp. 1128-1130 ◽  
Author(s):  
Yuichi Tozuka ◽  
Atsutoshi Ito ◽  
Hiroko Seki ◽  
Toshio Oguchi ◽  
Keiji Yamamoto
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
X Ray ◽  
Solid State Nmr Spectroscopy

scholarly journals Layer-by-Layer Structural Identification of 2D Ruddlesden-Popper Hybrid Lead Iodide Perovskites by Solid-State NMR Spectroscopy

2020 ◽  
Author(s):  
Jeongjae Lee ◽  
Woocheol Lee ◽  
Keehoon Kang ◽  
Takhee Lee ◽  
Sung Keun Lee
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Structural Features ◽  
Layer By Layer ◽  
Lead Iodide ◽  
Materials Properties ◽  
Non Invasive ◽  
Local Bonding ◽  
Halide Perovskites

Application of two-dimensional (2D) organic-inorganic hybrid halide perovskites for optoelectronic devices requires detailed understanding of the local structural features including the Pb-I bonding in the 2D layers and the capping ligand-perovskite interaction. In this study, we show that <sup>1</sup>H and <sup>207</sup>Pb solid-state Nuclear Magnetic Resonance (NMR) spectroscopy can serve as a non-invasive and complementary technique to quantify the composition and to probe the local structural features of 2D Ruddlesden-Popper phase BA<sub>2</sub>MA<i><sub>n</sub></i><sub>-1</sub>Pb<i><sub>n</sub></i>I<sub>3<i>n</i>+1</sub> (<i>n</i>=1-4) with butylammonium (BA) spacers. <sup>207</sup>Pb echo and <sup>1</sup>H-detected <sup>207</sup>Pb→<sup>1</sup>H heteronuclear correlation (HETCOR) experiments enables layer-by-layer structural detection of 2D halide perovskites. We show that the observed correlation between <sup>207</sup>Pb NMR shifts and mean Pb-I bond lengths around each Pb site allows us to probe the local bonding environment of Pb via its <sup>207</sup>Pb NMR shift. We envisage that this technique will be vital for better understanding the materials properties as determined by the local atomistic environments in multi-dimensional halide perovskites.

Dissecting the Effects of Water Guest Adsorption and Framework Breathing on the AlO4(OH)2 Centers of Metal-Organic Framework MIL-53 (Al) by Solid State NMR and Structural Analysis

2021 ◽  
Author(s):  
Alexander G. Stepanov ◽  
Alexander E. Khudozhitkov ◽  
Sergei S. Arzumanov ◽  
Alexander V. Toktarev ◽  
Svetlana Cherepanova ◽  
...  
Keyword(s):  
Solid State Nmr ◽  
Metal Organic Framework ◽  
Structural Phase ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Aluminium Atom ◽  
Quadrupole Coupling ◽  
Adsorption Of Water ◽  
Metal Organic ◽  
The Relationship

The relationship between the adsorption of water on MIL-53 (Al) MOF, the structural phase of MIL-53 (Al), and quadrupole coupling constant of 27Al framework aluminium atom (QCC) of the MOF...

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