杂环烯酮缩胺:构筑分子多样性稠杂环化合物的合成先导分子

杂环烯酮缩胺（HKAs）是一类构建分子多样性稠杂环化合物的多功能合成砌块,已被广泛应用于构筑多种多样的类天然杂环化合物和合成药物中。随着杂环烯酮缩胺研究的深入开展,其作为双亲核试剂与多种亲电底物反应取得了较大的进展。本文将基于HKAs的结构特征、反应性能,对以HKAs及1,1-烯二胺为合成子构建各种类型具有潜在生物活性的类天然多环稠杂环化合物进行综述。     

超小金纳米簇用于荧光及CT双模态成像的研究

基于金纳米簇强烈的量子限制效应（strong quantum confinement effect,SQCE）,采用一步合成法,制备了同时具有高效近红外荧光与CT双模态成像能力的超小金纳米簇.实验表明,通过优化合成比例以及合成条件,所合成的超小金纳米簇具有很大的斯托克斯（Stokes）位移、较高的荧光强度和X射线吸收效率.除此之外,该超小金纳米簇具有良好的单分散性、稳定性和生物相容性.4T1肿瘤细胞荧光成像实验结果表明,该纳米粒子可被肿瘤细胞快速、高效地摄取.     

4GPa超高压凝固Mg-6Zn-3Y合金的凝固组织及相分析

利用X射线衍射仪、扫描电镜并配合能谱分析研究了Mg-6Zn-3Y合金4 GPa超高压凝固组织.结果表明:在4 GPa超高压条件下凝固时,实验合金的凝固组织得到显著细化,基体α-Mg相的晶格间距有所减小;Zn在基体α-Mg中溶解度大幅提高,Y不溶于基体α-Mg;实验合金凝固组织中出现呈对称性的四瓣或六瓣花的初晶Y固溶体,该初晶花瓣形貌完整、尺寸较大,显示其充分自由生长;先发生的共晶反应的共晶组织为成“簇”分布的共晶团,共晶相呈点状或棒状;后发生的共晶反应的组织为离异共晶.超高压凝固显著地改变了实验合金的凝固过程.     

HO3+ 杂Ge-In-Sb-S玻璃陶瓷光谱特性

采用熔融淬冷法和热处理工艺制备了系列掺Ho3+的透明G eS2-In2S3-Sb2S3硫系玻璃陶瓷.测试了Ho3掺杂的基质玻璃和玻璃陶瓷样品的密度、显微硬度、红外光谱以及在900 nm激光泵浦下的近红外及中红外荧光光谱.结果表明:热处理后样品析出的晶相为In2S3和Sb2S3颗粒的混合体,晶粒尺寸限制在～100 nm以...     

The influence of KH-550 on properties of ammonium polyphosphate and polypropylene flame retardant composites

Ammonium polyphosphate (APP)/polypropylene (PP) composites were prepared by melt blending and extrusion in a twin-screw extruder. APP was first modified by a silane coupling agent KH-550 then added to polypropylene. The surface modification of APP by the coupling agent decreased its water solubility and its interface compatibility with the PP matrix. Limiting oxygen index (LOI) and thermogravimetric analysis (TGA) were used to characterize the flame retardant property and the thermal stability of the composites. The addition of APP improved the flame retardancy of PP remarkably. The crystal structures of APP/PP composites were characterized by X-ray diffraction (XRD). The results indicated that β-crystal phase PP may be formed. The structures and morphologies of APP, KH-550/APP and APP/PP composites were characterized by field-emission scanning electron microscope (FESEM). The mechanical property tests showed good mechanical properties of composite materials. Compared with unmodified one, the impact strength, tensile strength and elongation of modified APP/PP were all improved.     

Preparation and characterization of modified graphite oxide/poly(propylene carbonate) composites by solution intercalation

Modified graphite oxide (MGO)/Poly (propylene carbonate) (PPC) composites with excellent thermal and mechanical properties have been prepared via a facile solution intercalation method. An intercalated structure of MGO/PPC composites was confirmed by X-ray diffraction and scanning electron microscope. The thermal and mechanical properties of MGO/PPC composites were investigated by thermal gravimetric analysis, differential scanning calorimetric, dynamic mechanical analysis, and electronic tensile tester. Due to the nanometer-sized dispersion of layered graphite in PPC matrix and the strong interfacial interaction between MGO and PPC, the prepared MGO/PPC composites exhibit improved thermal and mechanical properties in comparison with pure PPC. Compared with pure PPC, the MGO/PPC composites show the highest thermal stability and the T_g is 13.8 °C higher than that of pure PPC, while the tensile strength (29.51 MPa) shows about 2 times higher than that of pure PPC when only 3.0 wt.% MGO is incorporated. These results indicate that this approach is an efficient method to improve the properties of PPC.     

Asymmetric iodoamination of chalcones and 4-aryl-4-oxobutenoates catalyzed by a complex based on scandium(III) and a N,N'-dioxide ligand

Highly diastereo‐ and enantioselective iodoamination of chalcones, 4‐aryl‐4‐oxobutenoates, and a trifluoro‐substituted enone has been accomplished in the presence of a chiral N,N′‐dioxide/[Sc(OTf)₃] complex (0.5–2 mol %), delivering the desired vicinal anti‐α‐iodo‐β‐amino carbonyl compounds regioselectively in high yields (up to 97 %) and with excellent diastereoselectivities (>99:1 d.r.) and enantioselectivities (up to 99 % ee). Enantiopure syn‐α‐iodo‐β‐amino products could also be obtained from the isomerization of particular iodo compounds. TsNHX species (X=Cl, Br, I), generated from the reactions between the halo sources and TsNH₂, were further confirmed as the active species in the haloamination reactions involved in the formation of the key halonium ion intermediates. A typical haloamination dependency was observed, with reactivity decreasing in the order NBS>NIS?NCS.     

钌基氨合成催化剂的制备方法

与铁催化剂相比较,钌基氨合成催化剂具有低温、低压、高活性的特点。对于不同的载体、制备方法和制备条件对催化剂性能影响较大。本文从载体的前处理、活性组分钌和助剂的加入方式等方面简要阐述了钌基氨合成催化剂制备方法的研究进展,介绍了熔融法、升华法、离子交换法、超声法、沉淀法、溶胶-凝胶法、浸渍法、微波辅助法等钌基氨合成催化剂制备方法,指出了一些制备方法的不足之处,并展望了钌基氨合成催化剂制备方法的研究方向。     

羧甲基淀粉与烷基二甲基苄基氯化铵的相互作用研究

通过电导法、荧光法、粒度法等方法研究了羧甲基淀粉与3种不同碳数烷基二甲基苄基氯化铵之间的相互作用。结果表明,羧甲基淀粉与长链烷基二甲基苄基氯化铵在小于单纯表面活性剂临界胶束浓度（cmc）1～2个数量级的浓度下发生复合,并产生沉淀。当表面活性剂烷基链增加且浓度增大时,表面活性剂长碳链间的疏水作用及与羧甲基淀粉间的疏水作用...     

2-亚磷酸二乙酯基杂环烯酮缩胺类化合物的合成

用廉价易得原料Mn(OAc)2-KMnO4体系代替昂贵的Mn(OAc)3催化二甲缩硫醚(1)与亚磷酸二乙酯反应获得结构新颖的2-亚磷酸二乙酯基缩硫醚化合物2a～2d.然后,化合物2a～2d与二胺类化合物3反应以较高产率合成了一系列2-亚磷酸二乙酯基杂环烯酮缩胺(4).