Synthesis and Crystal Structure of (7R,8S,9S,12S)-13,14-dehydro-1-(4-fluorobenzy oxy)-N-methyl-2,13-dimethoxy-12-hydroxymorphinane

The title compound (7R,8S,9S,12S)-13,14-dehydro-1-(4'-fluorobenzyloxy)-N-methyl-2,13-dimethoxy-12-hydroxymorphinane was synthesized by the reaction of O-4-bromobenzyl-sinomenine with lithium aluminum hydride. Its chemical structure was determined by Ⅹ-ray single-crystal diffraction. The crystal belongs to triclinic, space group P1 with Mr = 439.51, a=7.7236(1), b = 8.7282(1), c = 9.9342(2) A, a = 81.176(1),β= 67.43, γ= 64.577(1)°,μ = 0.76 mm<'-1>,V= 558.45(2) A<'3>, Z = 1, Dc = 1.307 mg/m<'3>, F(000) = 234 and T= 133 K.     

Crystal Structure and Photoluminescence of a New Cadmium Complex with 6,7-Dicyanodipyridoquinoxalin

The reaction of CdCl2 with 6,7-dicyanodipyridoquinoxaline (DICNQ) by solvothermal reaction gives rise to a coordination polymer [CdCl2(DICNQ)]n 1. Single-crystal X-ray diffraction analysis reveals that the compound in space group Pbcn creates 1-D chloro-bridging chains. Crystal data for 1: a = 6.756(1), b = 35.371(6), c = 7.027(1) , V = 1679.1(5) 3, Z = 4.00, C16H6CdCl2N6, Mr = 465.57, Dc = 1.842 g/cm3, μ = 1.630 mm-1, F(000) = 904, S = 1.005 and T = 293(2) K. The final R = 0.0376 and wR = 0.1029 for 1291 observed reflections with I > 2σ(I), and R = 0.0499 and wR = 0.1125 for all data. The 1-D chloro-bridging chains are parallel-stacked in the a and b directions, and further stabilized through π-stacking interactions, hydrogen-bonding interactions and C≡N···π interactions to generate a 3-D structure. Compound 1 displays intense bluish-green photoluminescence from the intraligand charge-transfer of the DICNQ ligand and the Cl--to-DICNQ charge-transfer mechanism which is probed by the density of states (DOS) calculations.     

锂离子电池负极CaSnO3制备及性能

应用水热法合成前驱物CaSn（OH）6,经高温煅烧而得CaSnO3.XRD、SEM、DSC-TGA表征其物相、表面形貌和相变过程,调节溶剂水和乙醇比例,可有效地控制前驱物的形态,从立方块到内凹立方块乃至枝状结构变化,高温煅烧前驱体可得到CaSnO3样品.CaSnO3电极比容量为334.4 mAh/g,呈现出优良的循环寿...     

Review on underwater sound absorption materials and mechanisms

随着我国加速实施海洋强国战略,对先进水下吸声材料的需求日益迫切.与空气吸声不同,水下的高静水压力和复杂的海洋环境对水下吸声材料提出了更为苛刻的要求.吸声问题的本质是如何将弹性能高效地转化为热能或其他形式能量.本文综述了主要以聚合物分子内摩擦机制及界面耗能机制为基础的传统水下吸声材料.传统水下吸声材料面临的主要是其在低频及高静水压力下吸声性能差的问题.这是因为：一方面受质量密度定律的限制,有限厚度的水下吸声材料无法有效吸收水中传来的低频声波;另一方面,在高静水压力下,弹性材料如高分子聚合物会变“硬”,从而大大降低了声波弹性能的转换效率.随着局域共振理论及超材料概念的提出,发展出了一系列新型水下吸声材料,为解决水下吸声材料遇到的难题提供了新思路.局域共振理论的特点是可以用小尺度结构控制长波声波的传播,从而可以解决低频吸声问题.本文重点综述了局域共振理论,以及由此发展出的声子木堆、声子玻璃等新型水下吸声材料.声子玻璃材料在局域共振理论基础上,通过引入多孔金属骨架结构提高了材料的抗压性能,从而解决了高静水压力下材料吸声性能变差的问题.本文最后对水下吸声材料未来发展方向进行了展望.     

Enhanced Survivin siRNA Delivery Using Cationic Liposome Incorporating Fatty Acid-modified Polyethylenimine

We described a novel approach for survivin siRNA cellular delivery via a cationic liposome incorporating fatty acid-modified polyethylenimine. A linoleic acid derivative of branched polyethylenimine(PEI, M_w=25 kDa), PEI-LA, was synthesized and incorporated into the liposome. The properties of the liposome, cytotoxicity, cellular uptake of cancer cells for survivin siRNA, survivin protein downregulation levels were investigated. PEI-modified liposome showed a lower cytotoxicity and delivered survivin siRNA into HeLa cells and A549 cells efficiently compared with PEI-25kDa.