Nitrogen-15 shielding in trans-azobenzene

1989 ◽  
Vol 67 (7) ◽  
pp. 1219-1224 ◽  
Author(s):  
Roderick E. Wasylishen ◽  
William P. Power ◽  
Glenn H. Penner ◽  
Ronald D. Curtis
Keyword(s):  
Solid State Nmr ◽  
Experimental Error ◽  
Theoretical Calculations ◽  
Relative Orientation ◽  
General Direction ◽  
Molecular Plane ◽  
Shielding Constants ◽  
In Trans ◽  
Shielding Tensor ◽  
Trans Azobenzene

The principal values of the nitrogen nuclear magnetic resonance shielding tensor for trans-azobenzene have been measured and compared with theoretical values recently reported for trans-diazene. The shielding anisotropy for the two crystallographically nonequivalent molecules in trans-azobenzene is 925 and 880 ppm respectively, about 40% smaller than the value calculated for trans-diazene. Interestingly, the isotropic shielding constants for the two nonequivalent molecules are the same with in experimental error. The most shielded component of the 15N shielding tensor, σ33, is approximately perpendicular to the molecular plane, as it is in other planar π-systems; σ11, the least shielded component, is directed in the same general direction as the N—Cipso bond. The theoretical calculations overestimate the paramagnetic contribution to σ11. The magnitude and relative orientation of the nitrogen shielding tensor in trans-azobenzene are also compared with the corresponding phosphorus values in a diphosphene. Keywords: 15N chemical shielding anisotropy, solid state NMR, trans-azobenzene.

Resonant Raman excitation profile of the 220 cm−1 mode in trans-azobenzene

1992 ◽  
Vol 23 (3) ◽  
pp. 155-160 ◽  
Author(s):  
A. Biancalana ◽  
E. Campani ◽  
G. Gorini ◽  
G. Masetti ◽  
M. Quaglia
Keyword(s):  
Excitation Profile ◽  
In Trans ◽  
Resonant Raman ◽  
Trans Azobenzene

Probing solid iminobis(diorganophosphine chalcogenide) systems with multinuclear magnetic resonance

2009 ◽  
Vol 87 (1) ◽  
pp. 348-360 ◽  
Author(s):  
Bryan A Demko ◽  
Roderick E Wasylishen
Keyword(s):  
Solid State ◽  
Chemical Shift ◽  
Solid State Nmr ◽  
Magnetic Shielding ◽  
Chemical Shift Tensors ◽  
X Ray ◽  
X Ray Crystallography ◽  
Shielding Tensor ◽  
Nuclear Magnetic Shielding Tensors ◽  
Nuclear Magnetic

A 31P and 77Se solid-state NMR investigation of the iminobis(diorganophosphine chalcogenide) HN(R2PE)2 (R = Ph,iPr; E = O, S, Se) systems is presented. The NMR results are discussed in terms of the known HN(R2PE)2 structures available from X-ray crystallography. The phosphorus chemical shift tensors are found to be sensitive to the nature of the alkyl and chalcogen substituents. The nature of the R group also influences the selenium chemical shift tensors of HN(R2PSe)2 (R = Ph, iPr), which are shown to be sensitive to hydrogen bonding in the dimer structure of HN(Ph2PSe)2 and to the presence of disorder in the case of HN(iPr2PSe)2. Scalar relativistic ZORA DFT nuclear magnetic shielding tensor calculations were performed yielding the orientations of the corresponding chemical shift tensors. A theoretical investigation into the effect of the E-P···P-E “torsion” angle on the phosphorus and selenium chemical shift tensors of a truncated HN(Me2PSe)2 system indicates that the electronic effect of the alkyl group on the respective nuclear magnetic shielding tensors are more important than the steric effect of the E-P···P-E torsion angle.Key words: iminobis(diorganophosphine chalcogenide), solid-state NMR, 31P NMR, 77Se NMR, ZORA DFT.

S2 → S0 fluorescence in trans-azobenzene

1979 ◽  
Vol 68 (2-3) ◽  
pp. 267-271 ◽  
Author(s):  
C.G. Morgante ◽  
W.S. Struve
Keyword(s):  
In Trans ◽  
Trans Azobenzene

NMR spectroscopy of the phenyl derivative of germanium(IV) 5,10,15-tritolylcorrole

2016 ◽  
Vol 20 (01n04) ◽  
pp. 525-533
Author(s):  
Giampaolo Ricciardi ◽  
Daniel O. Cicero ◽  
Sara Lentini ◽  
Sara Nardis ◽  
Roberto Paolesse ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
2D Nmr ◽  
Functional Theory ◽  
Phenyl Derivative ◽  
Shielding Constants ◽  
Shielding Tensor ◽  
Experimental Values ◽  
Molecular And Electronic Structure

A thoroughly structural characterization of (TTC)GePh (TTC [Formula: see text] 5,10,15-tritolylcorrole; Ph [Formula: see text] phenyl) in solution has been carried out through a combination of 2D NMR (1H-1H COSY, 1H-1H ROESY, 1H-[Formula: see text]C HSQC and 1H-[Formula: see text]C HMBC) experiments and density functional theory (DFT) calculations of the molecular and electronic structure and the shielding constants. The 1H and [Formula: see text]C chemical shifts computed at DFT-S12g and DFT-SAOP levels of theory nicely reproduce the experimental values, the agreement between theory and experiment being especially good for the DFT-S12g results. The calculations prove to be able to capture the fine details of the NMR spectra and to resolve some assignment ambiguities related to the inherent conformational flexibility of the macrocycle. The calculations also provide an explanation of the observed chemical shift trends in terms of diamagnetic and paramagnetic components of the shielding tensor.

Revisiting Magnesium Chelation by Teichoic Acid with Phosphorus Solid-State NMR and Theoretical Calculations

2009 ◽  
Vol 113 (7) ◽  
pp. 2177-2183 ◽  
Author(s):  
Jason R. Wickham ◽  
Jeffrey L. Halye ◽  
Stepan Kashtanov ◽  
Jana Khandogin ◽  
Charles V. Rice
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Theoretical Calculations ◽  
Teichoic Acid

A Deuteron NMR Study on the Rotational Dynamics and the Orientation of Benzene Molecules Adsorbed on Graphite and Boron Nitride

1986 ◽  
Vol 41 (12) ◽  
pp. 1361-1368 ◽  
Author(s):  
B. Boddenberg ◽  
R. Grosse
Keyword(s):  
Boron Nitride ◽  
Solid State Nmr ◽  
Nmr Spectra ◽  
Static Field ◽  
Carbon Blacks ◽  
Graphitized Carbon ◽  
Nmr Study ◽  
Shielding Tensor ◽  
Axis Rotation ◽  
Set Up

The 52.7 MHz deuteron (2H) solid state NMR spectra of benzene-d6 adsorbed on microcrystalline boron nitride and on two graphitized carbon blacks (G raphon and Sterling MT) were measured at temperatures between 75 and 120 K. Both on boron nitride and on the graphitized carbons the benzene molecules exhibit hexad axis rotation which is fast on the NMR time scale. From the spectra of benzene on the graphitized carbon blacks it is deduced that the molecules are oriented with their planes parallel to the graphite basal planes exposed. At the deuteron sites the shielding tensor which is set up by the action of the static field on the susceptibility tensor of the graphite microcrystallites possesses a shielding anisotropy of + 150 ppm and + 200 ppm for the Graphon and Sterling MT blacks, respectively.

Characterization of Covalent Linkages in Organically Functionalized MCM-41 Mesoporous Materials by Solid-State NMR and Theoretical Calculations

2007 ◽  
Vol 111 (15) ◽  
pp. 3877-3885 ◽  
Author(s):  
Jerzy W. Wiench ◽  
Yamini S. Avadhut ◽  
Niladri Maity ◽  
Sumit Bhaduri ◽  
Goutam Kumar Lahiri ◽  
...  
Keyword(s):  
Solid State ◽  
Mesoporous Materials ◽  
Solid State Nmr ◽  
Theoretical Calculations ◽  
Mcm 41

Isotropie and Anisotropie Nuclear Magnetic Shielding of 113Cd in Cadmiumhalides, Cadmiumchalcogenides and in Cadmiumcarbonate

1978 ◽  
Vol 33 (6) ◽  
pp. 666-671 ◽  
Author(s):  
A. Nolle
Keyword(s):  
The Other ◽  
Magnetic Shielding ◽  
Axially Symmetric ◽  
Reference Scale ◽  
Cadmium Chalcogenides ◽  
Shielding Constants ◽  
Powder Samples ◽  
Shielding Tensor ◽  
Nmr Signals ◽  
Nuclear Magnetic

Abstract The NMR signals of 113Cd have been observed in powder samples of the cadmium halides CdF2, CdCl2, CdBr2· 4H2O, Cdl2, of the cadmium chalcogenides CdO, CdS, CdSe, CdTe and of CdCO3 . For 113Cd in CdCl2 , CdBr2-4H2O, CdS and in CdSe anisotropics of the nuclear magnetic shielding have been detected. The shielding tensor in these powders is axially symmetric. For the other specimens no anisotropics of the magnetic shielding have been found. The principal values of the magnetic shielding tensor and the shielding constants are given in an atomic reference scale.

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