A new tetrameric neodymium-silsesquioxane cage complex {[(i-C4H9)7(Si7O12)Nd]4NaCl} (1) was prepared by the reaction of NdCl3 with i-PrONa, and subsequent treatment with trisilanol [(i-C4H9)7(Si7O9)(OH)3] in toluene. The molecular structure of the complex was determined by single crystal X-ray diffraction. Preliminary study shows that complex 1 is active for highly cis-1,4 polymerization of isoprene (92% selectivity) in the presence of AlEt3 and Me3SiCl. 相似文献
A prominent methanol-tolerant characteristic of the PtCeOx/C electrocatalyst was found during oxygen reduction reaction process. The carbon-supported platinum modified with cerium
oxide (PtCeOx/C) as cathode electrocatalyst for direct methanol fuel cells was prepared via a simple and effective route. The synthesized
electrocatalysts were characterized by X-ray diffraction and transmission electron microscopy. It was found that the cerium
oxide within PtCeOx/C present in an amorphous form on the carbon support surface and the PtCeOx/C possesses almost similar disordered morphological structure and slightly smaller particle size compared with the unmodified
Pt/C catalyst. 相似文献
Zirconia (ZrO2) nanotubes have been synthesized using a facile anodizing process in organic electrolyte systems containing a low content
of fluoride. The nanotube architecture evolution was recorded at different anodization periods (1–24 h) by scanning electron
microscopy. A compact layer was found between the Zr substrate and its upper tubular layer after 1 h of anodization, whereas
after further anodization for 3 h the compact layer disappeared. Meanwhile, ZrO2 nanotubes turned to a uniform structure from top to bottom. However, after 18–24-h-long anodization, the uniform tubular
layer was replaced by a random layer composed of various structural defects. Since the compact layer was not completely dissolved,
the retained compact layer yielded O-rings with double walls on the outer surface of the nanotubes. 相似文献
Summary: Copolymers of poly(ethylene oxide) (PEO) and 5,5′‐azodisalicylic acid (Olsalazine, OLZ) were synthesized and evaluated by hydrolysis and in‐vitro biodegradation with azoreductase. It was found that changing the molecular weight of the PEO blocks affected the loading ratio of OLZ, and resulted in significant differences in the hydration and degradability of the copolymers. These novel azo‐containing copolymers can be used in colon‐specific drug delivery.
Release of 5‐ASA from OLZ and PEO‐OLZ copolymers incubated with rat cecum content in the presence of benzyl viologen and α‐D ‐glucose. 相似文献