Synthesis and characterization of synthetic polymer colloids colloidally stabilized by cationized starch oligomers

A method is developed for anchoring enzymatically degraded cationized starch as electrosteric stabilizers onto synthetic latices, using cerium(IV) to create free‐radical grafting sites on the starch. Direct anchoring of debranched starch onto a poly(methyl methacrylate) seed latex yields a latex stabilized by well‐defined oligosaccharides. Using α‐amylase to randomly cleave starch to form (1→4)‐α‐glucans, and a comonomer, N‐isopropyl acrylamide (NIPAM), whose corresponding polymer exhibits a lower critical solution temperature (LCST), creates a means to synthesize block (or graft) oligomers of oligosaccharide and synthetic polymer, which are water soluble at room temperature. Above 30 °C, they become amphiphilic and form self‐emulsifying nanoparticles (sometimes termed “frozen micelles”) from which a synthetic latex is grown after addition of methyl methacrylate, the collapsed NIPAM‐containing entities functioning as a type of in situ seed. This synthesis of stable synthetic latex particles is shown to have a high grafting efficiency. The starch fragments were characterized by ¹H solution‐state NMR before grafting, and ¹³C solid‐state cross‐polarization magic‐angle spinning (CP‐MAS) NMR was used to characterize the starch oligomers actually grafted on the final latex. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1836–1852, 2009     

ChemInform Abstract: The Crystal Structures of m,o‐Ce3Pt4Sn6 and Ce1‐xPt6Al13+2x.

Single crystals of Ce₃Pt₄Sn₆ (I) and Ce_1‐xPt₆Al_13+2x (x = 0.207, (II)) are isolated by mechanical fragmentation of specimens grown from self‐fluxes (Sn or Al, resp.) by slow cooling from the melt.     

一种新奇的d-f异双核配合物[Fe(phen)_3]_2[FeCe(tiron)_3]·6H_2O的水热合成、晶体结构和磁性

硝酸铁,硝酸铈,邻菲咯啉(phen)和钛铁试剂(Tiron)通过水热方法合成了一种d-f异双核配合物[Fe(phen)3]2[FeCe(tiron)3]·6H2O,tiron=C6H2O8S2。X-射线单晶衍射分析表明,晶体属立方晶系,P213空间群,晶胞参数为:a=2.19409(4)nm,V=10.5624(3)nm3,Z=4,F(000)=4648,R1=0.0451,wR2=0.1077,S=1.072。在具有C3对称性的[FeCe(tiron)3]6-单元中,Fe髥与6个酚氧配位形成一个反三棱柱配位多面体,Ce髥则与3个桥联的酚氧μ2-O和3个磺酸基的氧形成另一个与FeO6共用底面的反三棱柱配位多面体CeO6。配阳离子通过phen-phen之间的π-π相互作用和与配阴离子间的静电引力等作用组装成一种三角梅状准主/客体型的超分子。在2~300K温度范围内测试了配合物的变温磁化率,结果表明,Ce髥-Fe髥之间存在典型的反铁磁性相互作用。     

用于 NH3 选择催化还原 NO 反应的新型 Ce-P-O 催化剂

 报道了一种新型的可用于氨选择催化还原氮氧化物的 Ce-P-O 催化剂. 在空速为 20 000 h?1, 较宽的温度范围内经 500 oC 焙烧的 Ce-P-O 催化剂上表现出了较高的 NO 转化率 (可达到 90% 以上). 与 V-W-Ti 催化剂相比, 该催化剂具有一定的耐水蒸气和 SO2 能力以及较好的抗碱中毒性能.     

Novel Lanthanide Complexes of Ciprofloxacin: Synthesis,Characterization, Crystal Structure and in vitro Antibacterial Activity Studies

Novel lanthanide coordination compounds with ciprofloxacin (CPFX), including eleven complexes Ln(CPFX)₂Cl(H₂O), (Ln=Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb; n = 7, 8, 9) and crystalline [Ce(CPFX)₂ (H₂O)₄] Cl (H₂O)_3.25 (C₂H₅‐OH)_0.25, were synthesized. The crystal is of triclinic space group Pi with a= 1.3865(2) nm, b = 1.3899(3) nm, c = 1.6505(2) nm, a = 92.73(1)°, β= 114.39(1)°, γ=115.55 (1)°, Z = 2 and R = 0.0449. FT‐IR, electronic spectroscopy and X‐ray diffraction were employed to show that the lanthanide ion, which displays an eight‐coordinate structure, is chelated by 3‐carboxyl and 4‐keto oxygen donors of CPFX and two six‐membered chelate rings are formed. Test of in vitro antibacterial activity against E. coli, P. aeruginosa and S. aureus indicated that the in vitro antibacterial activity of the ligand can be improved by complexation with Ce(III).     

Catalytic Ketonization over Oxide Catalysts, Part IV. Cycloketonization of Diethyl Hexanodiate

Activity of 20 wt.% MO₂/S catalysts, where M = Mn, Ce and Th, and S = Al₂O₃ or SiO₂, has been studied in cycloketonization of diethyl hexanodiate at the temperature range 573-698 K in a flow system. Only moderate yields of cyclopentanone (<35%) were achieved. The highest yields of ketone were obtained over MnO₂/Al₂O₃ and MnO₂/SiO₂ catalysts - 33 and 27%, respectively. ThO₂ containing catalysts were the most active, whereby ester transformations were detected below 573 K. In the presence of all catalysts the formation of the main product was accompanied by various amounts of 2-ethylcyclopentanone, cyclopent-2-en-1-one, cyclopentene, 2-cyclopentylidenecyclopentanone and numerous unidentified by-products.     

Studies on the Synthesis of Morphinan Alkaloid： Preparation of the Key Allylic Silyl Ether Precursor

Morphinan alkaloid consisting of many diverse molecules has been attracting much attention of synthetic chemists because of their biologically significant activities and the intriguing structures1. As shown in the common nucleus 1 of these polycyclic frameworks, there is a unique quaternary carbon center with an aryl substituent representing a central synthetic challenge2. In connection with our constant investigations on the quaternary carbon chemistry3, we proposed a general and conceptually…     

准球心弧线摆动高速抛光用的高纯氧化铈

本文阐述了准球心弧线摆动高速抛光中与聚氨基甲酸乙酯抛光模相匹配的高纯氧化铈抛光粉经烧制处理后的抛光效率,添加剂的作用以及回收处理。