Drug Delivery and NMR Tensors Studies of Methamphetamine and Carbon-Nanotube Binding

Far, Johann; Ziglari, Alireza; Sayadian, Masoumeh; Shahriari, Sara; Khalilimofrad, M. S.; Malakian, Fariba; Elsagh, A; Моллаамин, Ф.

doi:10.1166/jctn.2015.4331

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“…Theoretical prediction of the two main parameters observed in NMR spectra, chemical shifts and indirect spin–spin coupling constants, could advance the analysis of experimental spectra, as well as predict spectral parameters of new, proposed chemical structures with improved in vivo activity, or a new method of drug delivery to target tissue. In this respect, computational chemistry has been considered as a widely used theoretical tool, supporting the synthesis of potential drugs [ 12 , 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Factors Governing the Chemical Stability and NMR Parameters of Uracil Tautomers and Its 5-Halogen Derivatives

et al. 2020

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We report on the density functional theory (DFT) modelling of structural, energetic and NMR parameters of uracil and its derivatives (5-halogenouracil (5XU), X = F, Cl, Br and I) in vacuum and in water using the polarizable continuum model (PCM) and the solvent model density (SMD) approach. On the basis of the obtained results, we conclude that the intramolecular electrostatic interactions are the main factors governing the stability of the six tautomeric forms of uracil and 5XU. Two indices of aromaticity, the harmonic oscillator model of aromaticity (HOMA), satisfying the geometric criterion, and the nuclear independent chemical shift (NICS), were applied to evaluate the aromaticity of uracil and its derivatives in the gas phase and water. The values of these parameters showed that the most stable tautomer is the least aromatic. A good performance of newly designed xOPBE density functional in combination with both large aug-cc-pVQZ and small STO(1M)−3G basis sets for predicting chemical shifts of uracil and 5-fluorouracil in vacuum and water was observed. As a practical alternative for calculating the chemical shifts of challenging heterocyclic compounds, we also propose B3LYP calculations with small STO(1M)−3G basis set. The indirect spin–spin coupling constants predicted by B3LYP/aug-cc-pVQZ(mixed) method reproduce the experimental data for uracil and 5-fluorouracil well.

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Section: Introductionmentioning

confidence: 99%