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...

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...

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.

In this work, experimental and theoretical study on the molecular structure and the vibrational spectra of Maleic anhydride is presented. The vibrational frequencies of the title compound were obtained theoretically by HF and DFT calculations employing the standard 6-311++G(d,p) basis sets for optimized geometry and were compared with Fourier transform infrared spectrum (FTIR) in the range of 1...

Combination of the dithiol N,N'-bis(2-mercaptoethyl)isophthalamide, abbreviated as BDTH2 and as 1, with excess H2SeO3 in aqueous acidic (pH ≈ 1) conditions resulted in precipitation of BDT(S-Se-S) (6), with a (77)Se NMR chemical shift of δ = 675 ppm, and oxidized BDT. When the reaction is conducted under basic conditions Se(IV) is reduced to red Se(0) and oxidized 1. No reaction takes place bet...

The orientational effect of p-YC(6)H(4) (Ar) on delta(Se) is elucidated for ArSeR, based on experimental and theoretical investigations. Sets of delta(Se) are proposed for pl and pd employing 9-(arylselanyl)anthracenes (1) and 1-(arylselanyl)anthraquinones (2), respectively, where Se-C(R) in ArSeR is on the Ar plane in pl and perpendicular to the plane in pd. Absolute magnetic shielding tensors...

The molecular structure of 1-thia-closo-decaborane(9), 1-SB(9)H(9), has been determined by the concerted use of gas electron diffraction and quantum-chemical calculations. Assuming C(4v) symmetry, the cage structure was distorted from a symmetrically bicapped square antiprism (D(4d) symmetry) mainly through substantial expansion of the tetragonal belt of boron atoms adjacent to sulfur. The S-B ...

Different lipase enzymes have been tested in order to perform regioselective acetylations on the eudesmane tetrol from vulgarin. High yields (95%) of 1,12-diacetoxy derivative (4) were achieved in 1 h with Candida antarctica lipase (CAL). However, only the 12-acetyl derivative (6) was obtained in similar yield with Mucor miehei (MML) or Candida cylindracea (CCL) lipases. The enzymatic protectio...

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,...