The 1H NMR spectra of a number of alkenes of known geometry were recorded in CDCl3 solution and assigned, namely ethylene, propene, 4-methylcyclohexene, 1,4-dimethylcyclohexene, methylene cyclohexane (in CFCl3 –CD2Cl2 at 153 K), 5-methylene-2-norbornene, camphene, bicyclopentadiene, styrene and 9-vinylanthracene. These results together with literature data for other alkenes, i.e. 1,3and 1,4-cyc...

magnesium oxide nanotubes of finite length are investigated by the density functional theory (dft) at the b3lyp/6-31g (d) level. the (6, 0) zigzag and (4, 4) armchair of mgo nanotubes were considered and nuclear magnetic resonance properties including isotropic and anisotropic chemical shielding parameters (csi and csa) were calculated for 25mg and 17o atoms of the optimized structures for the ...

as drug delivery systems nanoparticulan widely investigated because of many advantages such as smaller size,controlled drug release potential targeting ability, enhancement of therapeutic efficacy and reduction oftoxicity. so, carbon nanotubes have recently received considerable attention as alternative drug delivery carrierin this study we investigate interaction of tamoxifen with open-end of ...

Computational chemistry is an important tool for signal assignment of 27Al nuclear magnetic resonance spectra in order to elucidate the species of aluminum(III) in aqueous solutions. The accuracy of the popular theoretical models for computing the 27Al chemical shifts was evaluated by comparing the calculated and experimental chemical shifts in more than one hundred aluminum(III) complexes. In ...

Ring formation in phosphate systems is expected to influence both the magnitude and orientation of the phosphorus (P) nuclear magnetic resonance (NMR) chemical shielding anisotropy (CSA) tensor. Ab initio calculations of the P CSA tensor in both cyclic and acyclic phosphate clusters were performed as a function of the number of phosphate tetrahedral in the system. The calculation of the P CSA t...

conclusions comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations. materials and methods a retrospective, observational cross-sectional study on the application of...

D. Direct Nuclear Spin-Spin Interactions in Free Molecules. Internuclear Spacings and Shapes of Molecular Vibrational Potential IS. Direct Nuclear Spin-Spin Interactions in Rigid Solids. Atomic Spacings and Bond Angles F. Nuclear Paramagnetic Resonance Line Widths in Liquids and Gases Collision Narrowing G. The Effect of Nuclear Motion on Nuclear Resonance Spectra in Crystals. Hindered Rotatio...

Molecular symmetry is a key parameter which dictates the NMR chemical shielding anisotropy (CSA). Whereas correlations between specific geometrical features of molecules and the CSA are known, the quantitative correlation with symmetry--a global structural feature--has been unknown. Here we demonstrate a CSA/symmetry quantitative relation for the first time: We study how continuous deviation fr...

Introduction: The role of radiotherapy as a part of cancer management increases every year around the world. Thus, Radiation protection in the design of radiotherapy rooms are of great importance.   Materials and Methods: In present study using Monte Carlo method, MCNPX code, fourteen types of developed high density concretes with densities ranging from 2.45 ...

Geometrical structure, nuclear magnetic resonance (N1,1It) chemical shielding tensors, and chemical shiftsof silicon and carbon nucler are investigated for twn infinite size zigzag and armchair single-walled siliconcarbide nanotabes (SiCNTs). Geometrical structures of SieNTs, Sit bonds and bond angles of St and Cvertices in both zigzag and armchair nanotubes, Indicate that bond lengths are appr...