13C cross-polarization magic angle spinning (CP/MAS) NMR data for 2,2,5,7,8-pentamethylchroman-6-ol (2), 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox c) (3) and its acetate (4), 2-methoxy-2,2,5,7,8-pentamethylchroman-6-ol (5), 2-hydroxy-2,2,5,7,8-pentamethylchroman-6-ol (6) and 2,2,5,7,8-pentamethylchroman (7) are reported. A deshielding of 7.7 ppm for the carboxylic carbon wa...

The structures of three NH-indazoles (3-methyl, 3-trifluoromethyl and 3-trifluoromethyl-4,5,6,7tetrafluoroindazoles) have been determined by X-ray crystallography. These three compounds, together with 3-methyl-4,5,6,7-tetrafluoroindazole, whose X-ray structure could not be determined, have been studied using multinuclear magnetic resonance spectroscopy, including solid-state CPMAS. They all are...

The structure of the ortho-, meta- and para- hybrid diindolylmethane-phenylboronic acids and their interactions were optimized with by a quantum chemical method, using density functional theory at the (DFT) level. Thus, infrared bands were assigned based on the scaled theoretical wavenumbers by correlating the respective experimental data of the molecules. In addition, the corresponding ¹H-/13C...

3-(3-Dimethylammonio)propylammonio propanoate bromide (1), 4-(3-dimethylammonio)propylammonio butanoate bromide (2), and 5-(3-dimethylammonio)propylammonio pentanoate bromide (3) have been obtained in reaction of 1,1-dimethyl-1,3-propylenediamine with 3-bromopropionic acid, ethyl 4-bromobutyrate and 5-bromovaleric acid, respectively. The products have been characterized by FTIR, Raman and NMR s...

Nuclear magnetic shielding tensors computed by the gauge including atomic orbital ~GIAO! method in the Hartree–Fock self-consistent-field ~HF-SCF! framework are partitioned into magnetic contributions from chemical bonds and lone pairs by means of natural chemical shielding ~NCS! analysis, an extension of natural bond orbital ~NBO! analysis. NCS analysis complements the description provided by ...

The H and C Nuclear Magnetic Resonance (NMR) spectra of the retinyl chromophore in rhodopsin are investigated by using Quantum Mechanics/Molecular Mechanics (QM/MM) hybrid methods at the Density Functional Theory (DFT) B3LYP/631G*:Amber level, in conjunction with the Gauge Independent Atomic Orbital (GIAO) method for the ab initio Self-Consistent-Field (SCF) calculation of NMR chemical shifts. ...

Viên chức phục vụ đào tạo có vai trò quan trọng trong sự phát triển của Nhà trường. Thời gian qua, đội ngũ viên Trường Đại học Đồng Tháp đã nâng cao ý thức, trách nhiệm đối với công tác phục vụ tạo; không ngừng phấn đấu tập, lao động, sáng tạo, huy khả năng, trí tuệ để hoàn thành tốt nhiệm được giao.

we have evaluated the nmr shielding tensors for a:t,g:c,a:u in watson-crick, and u-quartet. we have computed nmr shielding tensors at b31yp level by using 6-31g(d) basis set. we have compute anisotropy and asymmetry in a:t,g:c,a:u and u-quartet. the nmr shielding tensors were calculated using the giao method. the natural bonding orbital analysis (nbo) were performed. nbo calculation have been ...

influence of aluminum, gallium, indium- doping on the boron-nitride nanotubes (bnnts) investigated with density functional theory (dft) and hartreefock (hf) methods. for this purpose, the chemical shift of difference atomic nucleus was studied using the gauge included atomic orbital (giao) approch. in the following, structural parameter values, electrostatic potential, thermodynamic parameters,...