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排序方式: 共有5992条查询结果,搜索用时 15 毫秒
991.
Lin MF Dyakov YA Tseng CM Mebel AM Lin SH Lee YT Ni CK 《The Journal of chemical physics》2005,123(5):054309
Photodissociation of pyridine, 2,6-d2-pyridine, and d5-pyridine at 193 and 248 nm was investigated separately using multimass ion imaging techniques. Six dissociation channels were observed at 193 nm, including C5NH5 --> C5NH4 + H (10%) and five ring opening dissociation channels, C5NH5 --> C4H4 + HCN, C5NH5 --> C3H3 + C2NH2, C5NH5 --> C2H4 +C3NH, C5NH5 --> C4NH2 + CH3 (14%), and C5NH5 --> C2H2 + C3NH3. Extensive H and D atom exchanges of 2,6-d2-pyridine prior to dissociation were observed. Photofragment translational energy distributions and dissociation rates indicate that dissociation occurs in the ground electronic state after internal conversion. The dissociation rate of pyridine excited by 248-nm photons was too slow to be measured, and the upper limit of the dissociation rate was estimated to be 2x10(3) s(-1). Comparisons with potential energies obtained from ab initio calculations and dissociation rates obtained from the Rice-Ramsperger-Kassel-Marcus theory have been made. 相似文献
992.
取代对苯二酚醚化物的合成研究 总被引:2,自引:0,他引:2
本文从取代的对苯三酚3出发、利用Williamson醚化反应合成了一系列它的醚化产物4a-4H,给出了它们的核磁共振数据(氢谱和碳谱)。讨论了影响醚化反应的一些因素,比较了不同烷化剂发生醚化反应的活泼性。 相似文献
993.
Lv Z Fu Y Hou S Wang D Wu H Zhang C Chu Z Zou D 《Physical chemistry chemical physics : PCCP》2011,13(21):10076-10083
A high-efficiency dye-sensitized solar cell prototype has been designed and fabricated, in which the working electrode and counter electrode are in direct contact and singly twisted. The cell is sealed in a capillary. In this solar cell configuration, the area ratio between the counter and working electrode is extremely low which allows the independent adjustment of electrolyte volume and the distance between counter electrode and photo-anode. Also it is more easily sealed compared to planar solar cell. The effects of TiO(2) film thickness, twisted pitch of counter electrode and length of device have been investigated. Our results indicate that this novel configuration has demonstrated excellent modularization function, three dimensional light harvesting capacities and the relative independence of incident light angles due to the symmetry structure. The power conversion efficiency of one cell of 9.5 cm in length can reach up to 5.41% at standard test condition (100 mW cm(-2)) and the power output may double under intense diffuse illumination. As far as we know, this is the longest and most efficient fiber-shaped dye-sensitized solar cell consisting of liquid electrolyte. The longer the fiber-shaped solar cell is, the more suitable it is for woven solar power textile if it is encapsulated in transparent flexible plastic capillary. 相似文献
994.
双N—乙酸取代氮氧杂大环及其镧系配合物的合成 总被引:1,自引:1,他引:1
首次合成了一种新的1.2-双(3,4:9,10-二苯并-5,8-二氧杂-1,12-二氮杂环十五烷-N-乙酸)乙烷大环配体,制备了它的8个镧系元素(La,Pr,Nd,Sm,EU,Gd,Dy,Yb)配合物,用红外光谱、元素分析、核磁共振谱及电导等方法进行了表征,讨论了可能的配位情况。 相似文献
995.
Mao Jiang-Gao Huang Jin-Shun Ma Jian-Fang Ni Jia-Zuan 《Transition Metal Chemistry》1997,22(3):277-280
The reaction of diglycolic acid, O(CH2CO2H)2, with Cu(NO3)2·2H2O and lanthanoid nitrate hydrate produces a series of novel Ln–Cu mixed metal complexes, [Ln2Cu3{O(CH2CO2)2}6]·nH2O (Ln=La, Nd, n=9; Ln=Er, n=6), which have been characterized by elemental analysis, i.r. spectroscopy, magnetic measurements and X-ray crystallography. The Ln3+ and Cu2+ ions are connected by the carboxylate groups of the ligands, resulting in the formation of a complicated network. 相似文献
996.
Synthesis of Enantioenriched Indolines by a Conjugate Addition/Asymmetric Protonation/Aza‐Prins Cascade Reaction 下载免费PDF全文
Blake E. Daniels Jane Ni Prof. Sarah E. Reisman 《Angewandte Chemie (International ed. in English)》2016,55(10):3398-3402
A conjugate addition/asymmetric protonation/aza‐Prins cascade reaction has been developed for the enantioselective synthesis of fused polycyclic indolines. A catalyst system generated from ZrCl4 and 3,3′‐dibromo‐BINOL enables the synthesis of a range of polycyclic indolines in good yields and with high enantioselectivity. A key finding is the use of TMSCl and 2,6‐dibromophenol as a stoichiometric source of HCl to facilitate catalyst turnover. This transformation is the first in which a ZrCl4?BINOL complex serves as a chiral Lewis‐acid‐assisted Brønsted acid. 相似文献
997.
Hiroki Hirai Kiichi Nakajima Soichiro Nakatsuka Kazushi Shiren Jingping Ni Shintaro Nomura Toshiaki Ikuta Takuji Hatakeyama 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(46):13785-13789
The development of a one‐step borylation of 1,3‐diaryloxybenzenes, yielding novel boron‐containing polycyclic aromatic compounds, is reported. The resulting boron‐containing compounds possess high singlet‐triplet excitation energies as a result of localized frontier molecular orbitals induced by boron and oxygen. Using these compounds as a host material, we successfully prepared phosphorescent organic light‐emitting diodes exhibiting high efficiency and adequate lifetimes. Moreover, using the present one‐step borylation, we succeeded in the synthesis of an efficient, thermally activated delayed fluorescence emitter and boron‐fused benzo[6]helicene. 相似文献
998.
ZeMin Zhang FuSheng Guo PengHu Guo JunLiang Liu ZhaoPing Ni MingLiang Tong 《中国科学:化学(英文版)》2012,55(6):934-941
Four 3d-4f heterometallic complexes, [CuⅡ LnⅢ (bpt) 2 (NO 3 ) 3 (MeOH)] (Ln = Gd, 1; Dy, 2; bptH = 3,5-bis(pyrid-2-yl)-1,2,4- triazole), [CuⅡ 2 LnⅢ 2 (μ-OH) 2 (bpt) 4 Cl 4 (H 2 O) 2 ]·6H 2 O (Ln = Gd, 3; Dy, 4), have been synthesized under solvothermal conditions. X-ray structural analyses reveal that 1 and 2 are isostructural while 3 and 4 are isostructural. In each complex, the copper and gadolinium or dysprosium ions are linked by two triazolate bridges and form a CuⅡ -LnⅢ dinuclear unit. The intramolecular Cu-Ln distances are 4.542, 4.525, 4.545 and 4.538 for 1, 2, 3 and 4, respectively. Two dinuclear CuLn units are bridged by two OH- groups into the zig-zag tetranuclear {CuⅡ 2 LnⅢ 2 } structures with the Ln(Ⅲ) Ln(Ⅲ) distances of 3.742 and 3.684 for 3 and 4, respectively. Magnetic studies show that the antiferromagnetic CuⅡ-LnⅢ interactions occur in 1 (J CuGd = 0.21 cm-1 ) and 2. The antiferromagnetic interaction occurs in complex 3 with J CuGd = 0.82 cm-1 and J GdGd = 0.065 cm-1 , while dominant ferromagnetic interaction occurs in complex 4. 相似文献
999.
偶氮苯衍生物因其具有特殊的共轭体系常用作光开关特性的三阶非线性光学(NLO)开关材料,但有部分带有特殊基团的偶氮类分子在一般条件下无法显示其性能.然而,这类分子在被调节之后能展示出优异的光控的NLO开关性能.以无光控的NLO开关性能的5-(N-4-偶氮苯基)氨甲基间苯二甲酸为研究对象,并对其潜在的光控NLO开关性能进行调控.经过调节后的这类分子在光照条件下能顺利地经历可逆的顺反异构化反应,且产生三阶非线性性能的转换.其Z-扫描实验结果显示处于反式构型的材料展示出反饱和吸收和自散焦特性;在光照之后,这类材料转化为顺式构型并展现出饱和吸收和自聚焦行为.三阶NLO性能的转换是由于材料的结构发生转变其内部电子产生重排,使得它们在激光刺激下产生不同的响应机制. 相似文献
1000.
316L不锈钢基体上磁控溅射Er2O3/Er涂层的后处理研究 总被引:1,自引:0,他引:1
采用磁控溅射的方法在316L不锈钢表面制备了氧化铒涂层.选用金属铒作为过渡层,研究了不同热处理温度对涂层相组成、表面形貌以及涂层与基底结合情况的影响.XRD,SEM及膜基结合力分析结果表明,带有过渡层的氧化铒涂层表面致密、均匀,退火处理使氧化铒结晶性能提高,经过800℃热处理,生成了金属间化合物ErFe3提高了涂层与基底的结合强度.绝缘电阻率测试结果表明.Er2O3涂层绝缘电阻率在1×1013~1×1015Ω·cm,绝缘性能良好. 相似文献