The title compound, meso‐C13H12O2S2, is in an anti conformation, with R and S configurations around the S atoms. The two O atoms are trans to each other, and the same applies for the two benzene rings. The phenylsulfinyl groups are nearly orthogonal to the central dithiomethane group, and the orientation of the two phenyl rings are determined by the interactions in which they are involved. The packing is built from molecular columns stabilized by weak C—H⋯O interactions. 相似文献
Trace quantities of laser ablated organic polymers were analyzed by using commercial capillary column gas chromatography/mass spectrometry; the instrument was modified so that the iaser ablation products could be introduced into the capillary column directly and the constituents of each peak in the chromatogram were identified by using a mass spectrometer. The present study takes advantage of the selective ion monitoring mode for significantly improving the sensitivity of the mass spectrometer as a detector, which is critical in anatyzing the trace quantities and confirming the presence or absence of the species of interest in laser ablated polymers. The initial composition of the laser ablated polymers was obtained by using an electron impact reflectron time-of-flight mass spectrometer and the possible structure of the fragments observed in the spectra was proposed based on the structure of the polymers. 相似文献
A simple approach to improve the structural ordering in block copolymer/nanoparticle nanocomposites is presented. It is to blend a small molecular weight homopolymer with the composites, which can uniformly swell the preferred domain where the nanoparticles locate and increase the conformational entropy of the domain. Consequently, the interfaces between the block copolymer domains become smooth that improves the long range order in the nanocomposites. Furthermore, the uniform swelling of the preferred domain by the homopolymer will allow higher loading of nanoparticles without adversely affecting the long range order.
Summary: Statistical random copolymers of 1H,1H‐perfluorooctyl methacrylate and 2‐dimethylaminoethyl methacrylate, poly(FOMA‐co‐DMAEMA), effectively stabilized the dispersion polymerization of methyl methacrylate in supercritical carbon dioxide. Free‐flowing, micron‐sized spherical PMMA particles could be produced with poly(FOMA‐co‐DMAEMA) containing 34 w/w% FOMA.
SEM image of PMMA particles prepared with poly(FOMA‐co‐DMAEMA) (34:66). 相似文献
A 3D‐QSAR study of celebrex‐based compounds of PDK1 inhibitors using comparative molecular field analysis (CoMFA) was carried out. The structures of the compounds were obtained using quantum chemistry calculation. CoMFA calculations for a number of grouped subsets of compounds gave q2 values of correlation in the range from 0 to 0.8. The low q2 values should be mainly due to the narrow span of biological activity. Calculations for several subsets of 11–13 compounds gave high q2 values, with 0.5–0.8. Factors affecting the results of the calculations are discussed. Calculated results with high q2 values suggest that further chemical modifications of the compounds could lead to enhanced activity and could be an aid in the design of celebrex‐based cancer drugs. 相似文献
We determined the minute amount of non-polar ginsenosides in red ginseng with a reversed-phase high-performance liquid chromatography-pulsed amperometric detection (RP-HPLC-PAD) method. Non-polar ginsenosides efficiently extracted by ethyl acetate were well separated in 40 min using a water–acetonitrile gradient eluent and detected by PAD under NaOH alkaline conditions. The ginsenoside detection limits (S/N = 3) were 0.03–0.10 ng. The coefficients of linear regression were 0.9972–0.9990. Intra- and inter-day precision (RSDs) was less than 8.34% and average recovery was 98.06–102.73%. The total amount of non-polar ginsenosides in hairy root of red ginseng was slightly higher than in the main root. 相似文献