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121.
首先用溶胶-凝胶法制备符合SrAl2O4:Eu^2 ,Dy^3 化学组成的溶胶,然后通过机械研磨、水热反应和微波加热反应三种不同的组装方法和微波还原扩散法使其进入主体ZSM-5沸石的孔道中。主客体材料的荧光光谱出现显著蓝移,余辉光谱出现400nm和517nm两个发射峰,两个余辉峰的相对发射强度随组装方法和组装浓度的改变而具有可调性,呈现有规律的变化。分析其原因是由于发光材料进入沸石的纳米级孔洞引起的。 相似文献
122.
Two new bismuth hydroxyl borates, Bi(2)O(2)[B(3)O(5)(OH)] (I) and Bi(2)O(2)[BO(2)(OH)] (II), have been synthesized under hydrothermal conditions. Their structures were determined by single-crystal and powder X-ray diffraction data, respectively. Compound I crystallizes in the orthorhombic space group Pbca with the lattice constants of a = 6.0268(3) ?, b = 11.3635(6) ?, and c = 19.348(1) ?. Compound II crystallizes in the monoclinic space group Cm with the lattice constants of a = 5.4676(6) ?, b = 14.6643(5) ?, c = 3.9058(1) ?, and β = 135.587(6)°. The borate fundamental building block (FBB) in I is a three-ring unit [B(3)O(6)(OH)](4-), which connects one by one via sharing corners, forming an infinite zigzag chain along the a direction. The borate chains are further linked by hydrogen bonds, showing as a borate layer within the ab plane. The FBB in II is an isolated [BO(2)(OH)](2-) triangle, which links to two neighboring FBBs by strong hydrogen bonds, resulting in a borate chain along the a direction. Both compounds contain [Bi(2)O(2)](2+) layers, and the [Bi(2)O(2)](2+) layers combine with the corresponding borate layers alternatively, forming the whole structures. These two new bismuth borates are the first ones containing [Bi(2)O(2)](2+) layers in borates. The appearance of Bi(2)O(2)[BO(2)(OH)] (II) completes the series of compounds Bi(2)O(2)[BO(2)(OH)], Bi(2)O(2)CO(3), and Bi(2)O(2)[NO(3)(OH)] and the formation of Bi(2)O(2)[B(3)O(5)(OH)] provides another example in demonstrating the polymerization tendency of borate groups. 相似文献
123.
Xiaolan Tong Shan Wang Jun Zuo Yingchong Ge Qiang Gao Suijun Liu Jianhua Ding Fen Liu Jianqiang Luo Jianbo Xiong 《中国化学快报》2021,32(2):604-608
Two new hydrostable two-dimensional(2 D) uranyl coordination complexes [(UO_2)_5(μ_3-O)_2(nbca)_2].7 H_2O(1) and [(UO_2)_3(nbca)_2(H_2O)_3]·2 H_2O(2)(H_3 nbca=5-nitro-1,2,3-benzenetricarboxylic acid) were hydrothermal synthesized.Single-crystal structural refinements reveal that both of the two complexes were formed by the packing of 2D uranyl coordination sheets via the hydrogen bonds.The nbca ligand coordinating to the uranyl polyhedron centers constructed the 2D sheets.There are UO_8 hexagonal bipyramids and UO_7 pentagonal bipyramids in 1 while only U07 pentagonal bipyramids in 2.Photocatalytic degradation of rhodamine B(RhB) in aqueous solution was studied.Complex 2 possesses better performance than 1 with 96.2 % of the RhB was degraded in only 60 min.Mechanism studies reveal that the dissolved oxygens are essential to the RhB degradation.The photocurrent density of 2 is more stable than that of 1,which indicating the stronger ability to separate photoexcited electrons and hole pairs of 2. 相似文献
124.
Organic quantum well and superlattice characteristics in quasi-one-dimensional multiblock copolymers
A tight-binding calculation was presented to describe multiblock copolymers, such as [...-(PA)x-(PPP)y-...] composed of PA (polyacetylene) and PPP (poly(p-phenylene). It is found that a copolymer has a quantum well and superlattice characteristics, and evident is the effect of the composite lengths, the interfacial couplings and the electron-phonon interactions on the electronic properties of a copolymer. The quantum tunneling, the Franz-Keldysh effect and the quantum confinement can be generated under an applied electric field. These results were compared to those of traditional inorganic quantum well and superlattice systems. 相似文献
125.
Dr. Shihui Li Dr. Meiyan Wang Bo Liu Lei Li Prof. Jianhua Cheng Dr. Chunji Wu Dr. Dongtao Liu Prof. Dr. Jingyao Liu Prof. Dr. Dongmei Cui 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(47):15493-15498
The first four‐coordinate methanediide/alkyl lutetium complex (BODDI)Lu2(CH2SiMe3)2(μ2‐CHSiMe3)(THF)2 (BODDI=ArNC(Me)CHCOCHC(Me)NAr, Ar=2,6‐iPr2C6H3) ( 1 ) was synthesized by a thermolysis methodology through α‐H abstraction from a Lu–CH2SiMe3 group. Complex 1 reacted with equimolar 2,6‐iPrC6H3NH2 and Ph2C?O to give the corresponding lutetium bridging imido and oxo complexes (BODDI)Lu2(CH2SiMe3)2(μ2‐N‐2,6‐iPr2C6H3)(THF)2 ( 2 ) and (BODDI)Lu2(CH2SiMe3)2(μ2‐O)(THF)2 ( 3 ). Treatment of 3 with Ph2C?O (4 equiv) caused a rare insertion of Lu–μ2‐O bond into the C?O group to afford a diphenylmethyl diolate complex 4 . Reaction of 1 with PhN=C?O (2 equiv) led to the migration of SiMe3 to the amido nitrogen atom to give complex (BODDI)Lu2(CH2SiMe3)2‐μ‐{PhNC(O)CHC(O)NPh(SiMe3)‐κ3N,O,O}(THF) ( 5 ). Reaction of 1 with tBuN?C formed an unprecedented product (BODDI)Lu2(CH2SiMe3){μ2‐[η2:η2‐tBuNC(=CH2)SiMe2CHC?NtBu‐κ1N]}(tBuN?C)2 ( 6 ) through a cascade reaction of N?C bond insertion, sequential cyclometalative γ‐(sp3)‐H activation, C?C bond formation, and rearrangement of the newly formed carbene intermediate. The possible mechanistic pathways between 1 , PhN?C?O, and tBuN?C were elucidated by DFT calculations. 相似文献
126.
Nicolaou KC Stepan AF Lister T Li A Montero A Tria GS Turner CI Tang Y Wang J Denton RM Edmonds DJ 《Journal of the American Chemical Society》2008,130(39):13110-13119
The molecular design, chemical synthesis, and biological evaluation of two distinct series of platensimycin analogues with varying degrees of complexity are described. The first series of compounds probes the biological importance of the benzoic acid subunit of the molecule, while the second series explores the tetracyclic cage domain. The biological data obtained reveal that, while the substituted benzoic acid domain of platensimycin is a highly conserved structural motif within the active compounds with strict functional group requirements, the cage domain of the molecule can tolerate considerable structural modifications without losing biological action. These findings refine our present understanding of the platensimycin pharmacophore and establish certain structure-activity relationships from which the next generation of designed analogues of this new antibiotic may emerge. 相似文献
127.
多批次肝衰竭患者呼出气体的电喷雾萃取电离质谱检测及代谢组学数据分析 总被引:1,自引:0,他引:1
采用高分辨电喷雾萃取电离质谱(EESI-MS)技术对肝衰竭患者和健康志愿者呼出气体样本进行快速检测, 结合多块偏最小二乘分析(MB-PLS)方法, 对多批次获取的呼出气体代谢数据进行统计建模分析, 并与传统的PLS方法进行比较. 结果表明, MB-PLS方法能有效消除批次差异对统计建模的影响. 此外, 利用MB-PLS模型变量VIP值对变量进行筛选, 可降低数据的冗余, 消除无关变量对模型的影响, 从而有效提高了模型的性能. 相似文献
128.
129.
大学化学教学中绿色化学教育的渗透 总被引:56,自引:0,他引:56
本文列举了有机化学教学中大量的绿色化学教育实例 ,指出在大学化学教学中渗透绿色化学教育的必要性和可行性 相似文献
130.