Synthesis, Crystal Structure and Spectrometry Study of Chiral N-Ethyl-N'-(2',3',4',6'-tetra-O-acetyl-β-D-glycosyl)-thiocarbamide

The structure of chiral N-ethyl-N-(2,3,4,6-tetra-O-acetyl-b-D-glycosyl)-thio- carbamide was determined by X-ray diffraction method. It crystallizes in the monoclinic system, space group P21 with a = 7.6560(15), b = 10.311(2), c =14.181(3) ? b =100.88(3), C17H26N2O9S, Mr = 434.46, V = 1099.3(4) ?, Z = 2, Dc = 1.312 g/cm3, F(000) = 460, m = 0.196 mm-1, R = 0.0704 and wR = 0.1655. The total independent reflections were 5098, of which 1875 were observed with I ≥2s(I). The hexopyranosyl ring adopts a chair conformation. All the ring substituents are in the equatorial positions. The acetoxylmethyl group is in the gauche-gauche conformation. The S atom is in synperiplanar conformation, while the NCNC linkage is antiperiplanar. X-ray analysis shows that the absolute configuration of the chiral carbon atom at C(1) was proved to be b-form. The 1H NMR spectra and IR are in good agreement with the result of crystallography analysis. The NH…O intermolecular hydrogen bonds link the molecules into infinite chains connected by CH…O interactions.

Theoretical Study on the Structural and Electronic Properties of Thiocarbamide Hydrochloride

In the present paper, the electronic band structure, density of states （DOS）, and projected density of states （PDOS） analysis of thiocarbamide hydrochloride are reported. Calculations of the electronic properties have been carried out on the basis of fully self-consistent pseudopotential method using DFT. The results show that near the Fermi level, more prominent densities of states are seen between -8 eV and -6 eV in the valence band mainly due to the Cl-3p, N-2p and S-3p orbitals.

Thermodynamics and Kinetics of Au（Ⅲ） and Ag（Ⅰ） Sorption on to Silicon-Organic Polymer

Sorption method is used for analysis of teclmological, geological and hydro-chemical samples with low content of precious metals and chemical pre-concentration of technological solution. Synthesized silicon-organic polymer containing thiocarbamide group, which named poly[bis -N,N＇-（3-silsesquioxanilpropyl）-thiocarbamide]-（PSTM-3T） was used in this investigation. Sorption of Au（III） and Ag（I） ions from aqueous solutions of nitric acid has been studied using the silicon-organic polymer （PSTM-3T） under different experimental conditions. Better sorption was obtained at temperature 55 ℃, 3 mol/L of nitric acid solution and contact time 300 min and 240 min for Ag（I） and Au（Ⅲ）.Thermodynamic parameters were calculated by Van＇t Hoffequation. The negative values of△G0 at different temperatures indicate the feasibility of the process and the values become more negative with increase in temperature. The positive values of △H0 and AS0 indicate that the sorption process is endothermic and determine the disorderliness of the sorption at solid-liquid interface. Experimental data were evaluated to find out kinetic characteristics and found that the sorption of Au（Ⅲ） followed pseudo-second order model and the sorption of Ag（Ⅰ） followed pseudo-first order model. The sorption capacity increased with the increase in temperature and reached maximum value at 323 K and 328 K for Au（Ⅲ） and Ag（Ⅰ）. The maximum sorption capacity of PSTM-3T for Au（Ⅲ） and Ag（Ⅰ） evaluated 333 and 129 mg/g.