Theoretical Calculation of13C Chemical Shielding Anisotropy in Some Organic Compounds. II.
نویسندگان
چکیده
منابع مشابه
Continuous symmetry analysis of NMR chemical shielding anisotropy.
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...
متن کاملCalculation of the Effective Chemical Shielding Anisotropy in L-Alanyl-L-Alanine, Conformational and Charge Dependence Study
Abstract. DFT quantum-chemical calculations were carried out for the cationic, zwitterionic and anionic form of the L-Alanyl-L-Alanine di-peptide that can be experimentally accessed at different pH. The N NMR chemical shielding tensor of the amide nitrogen was used for theoretical modeling of the cross-correlated relaxations. In particular, effective chemical shielding anisotropies (effective C...
متن کاملChemical Simulation and Quantum Chemical Calculation of Lignin Model Compounds
The conformational preferences of the lignin guaiacyl structural unit were studied by several quantitative chemistry calculation methods using vanillin as a model compound. The potential energy surfaces of the vanillin molecule were scanned by the methods of HF and DFT to find the most stable conformation, as well as three local minimum conformations and six transient conformations. Bonds stren...
متن کاملPotentiometric Determination of Acidity Constants of Some Synthesized Organic Compounds in Organic-Water Media
The acidity constants of some synthesized protonated pyrazolo quinazoline compounds were determined potentiometrically at ionic strength of 0.1 M in DMF: water (60:40 v/v) system at different temperatures (298.15 K to 318.15 K). The pKa values have been found to increase with increasing electron-donating nature of substitutions. Some thermodynamics parameters such as enthalpy (ΔH°), Gibb’s free...
متن کاملMolecular aggregations and anisotropy photoinduction in organic compounds
The work is dedicated to a study of anisotropy photoinduction during the light-stimulated molecular aggregations in organic compounds. The case of gelatin or polyvinyl films saturated by azo dyes is considered. By using the video and spectral techniques, the time-formation picture of optical image is studied. It is shown that in this case the image is formed in a similar way as in silver emulsi...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Bulletin of the Chemical Society of Japan
سال: 1975
ISSN: 0009-2673,1348-0634
DOI: 10.1246/bcsj.48.841