Tensor magnetic shielding

Table 2. GIAO DFT-B3LYP/cc-pCVDZ-sd C magnetic shielding tensors (in ppm) in Ceo> C70 and C,...

When comparing the magnetic shielding tensors in Cgo and it is observed that the six extra electrons in the latter yield an important increase in the anisotropy and a strong shielding effect in the isotropic part of the nuclear shielding. 

Aluminum Magnetic Shielding Tensors and Electric Field Gradients for Aluminum(I) Hydride, Aluminum(I) Isocyanide, and the Aluminum(I) Halides Ab Initio Calculations... 

Results and Discussion. The calculated aluminum shielding tensors for A1H, A1F, A1C1 and A1NC for a variety of basis sets are presented in Table II. This particular family of basis sets was chosen as it is the one most commonly used in shielding calculations, especially for large systems. The experimental magnetic shielding tensors are obtained from... 

Table II Aluminum Magnetic Shielding Tensors for A1H, A1F, A1C1 and AlNCa...

Table III Nuclear Magnetic Shielding Tensors (in ppm) for Group 13 Nuclei of Several Diatomic Molecules1...

Phosphorus magnetic shielding tensors, general phosphido ligands in transition metal complexes, 1, 472 Phosphorus(III) mercury compounds, preparation, 2, 425-426 Phosphorus—metal complexes, characteristics, 2, 34 Phosphorus—nitrogen-containing rings, chromium carbonyl link, 5, 225... 

Another important extension of the theory concerns NMR chemical shift. Yamazaki et al. proposed a theory for computing the chemical shift of solvated molecules [17]. The nuclear magnetic shielding tensor o-x of a nucleus X can be represented as a mixed second derivative of the free energy A with respect to the magnetic field B and the nuclear magnetic moment mx ... 

The first term, cr0(T), is a statistical average of the nuclear magnetic shielding tensor over all possible orientation of the molecule in the magnetic field and is different for the isotopomers. Theoretical aspects of isotope shifts were covered by Jameson and Osten.7... 

Calculation of nuclear magnetic shielding tensors for embedded molecules... 

The magnetic shielding tensor a is the sum of a diamagnetic part crd and a paramagnetic part ap,... 

Fig. 7a, b The relationship between the distance d between the sulfur and the carbon in the P=S H-C and the P-S- H-C units and the values of the principal elements of the P nuclear magnetic shielding tensors calculated by the DPT GIAO method... 

The NMR characteristics of phosphirenes once again include a strong upfield shift of the 31P resonance and very high J (C—P) coupling constants. The parameters for a representative phos-phirene are listed in Table 4. The 31P magnetic shielding tensor components of phosphirene (3) have also been measured <87CPL(136)224>. 

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