Crystal structure determination of new antimitotic agent bis(p-fluorobenzyl)trisulfide.

The purpose of this research was to investigate the physical characteristics and crystalline structure of bis(p-fluorobenzyl)trisulfide, a new anti-tumor agent. Methods used included X-ray single crystal diffraction, X-ray powder diffraction (XRPD), Fourier-transform infrared (FT-IR) spectroscopy, differential scanning calorimetric (DSC) and thermogravimetric (TG) analyses. The findings obtained with X-ray single crystal diffraction showed that a monoclinic unit cell was a = 12.266(1) A, b = 4.7757(4) A, c = 25.510(1) A, beta = 104.25(1) degrees ; cell volume = 1,448.4(2) A(3), Z = 4, and space group C2/c. The XRPD studies of the four crystalline samples, obtained by recrystallization from four different solvents, indicated that they had the same diffraction patterns. The diffraction pattern stimulated from the crystal structure data is in excellent agreement with the experimental results. In addition, the identical FT-IR spectra of the four crystalline samples revealed absorption bands corresponding to S-S and C-S stretching as well as the characteristic aromatic substitution. Five percent weight loss at 163.3 degrees C was observed when TG was used to study the decomposition process in the temperature range of 20-200 degrees C. DSC also allowed for the determination of onset temperatures at 60.4(1)-60.7(3) degrees C and peak temperatures at 62.1(3)-62.4(3) degrees C for the four crystalline samples studied. The results verified that the single crystal structure shared the same crystal form with the four crystalline samples investigated.

[Study on the mechanism of the interaction between montmorillonite and bacterium].

AIM: To investigate the mechanism of the interaction between montmorillonite and bacteria by studying the reactions of different charges of montmorillonites with bacteria. METHODS: Bacteriostatic test: one loop of E. coli and Staphylococcus aureus at the concentration of 1 x 10(6).mL-1 was incubated to the plate culture medium containing different concentrations of montmorillonite, and incubated 24 h to observe the growth of bacteria. Bacterial adsorptive test: different amounts of montmorillonite were added into the artificially simulated intestinal solution (containing bacteria 1 x 10(7).mL-1). After the culture, the bacterial colonies were counted. RESULTS: The results showed that montmorillonite per se showed no bacteriostatic or bactericidal effect, but after exchange with metal ion and functional groups which inhibits bacteria, then it showed these activities. Adsorption was the main way between montmorillonite and bacteria. The special way of fixing bacteria into the "carriage" of montmorillonite gel which carry this structure was its pharmacological basis of curing diarrhea. The adsorption effect was related to layer charge density of the montmorillonites. CONCLUSION: Montmorillonite showed adsorption ability of bacteria with minus related to its layer charge, but has no bacteriostatic and bactericidal effect.