首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   4篇
  免费   2篇
  国内免费   4篇
化学   8篇
物理学   2篇
  2022年   1篇
  2021年   1篇
  2011年   3篇
  2010年   1篇
  2009年   1篇
  2008年   1篇
  2007年   1篇
  2004年   1篇
排序方式: 共有10条查询结果,搜索用时 15 毫秒
1
1.
张晓燕  宋海滨  唐良富 《化学学报》2011,69(21):2567-2573
通过三苯基锡基-双(3,5-二甲基吡唑)甲烷与羰基钼的反应合成了钼锡键合的四元金属杂环化合物CH(3,5- Me2Pz)2Mo(CO)3SnPh3 (Pz=1-吡唑基). 当用叔丁基异腈处理该化合物及其钨类似物时, 伴随着有机锡结构单元的丢失, 金属钼(钨)上发生还原消除并分解得到化合物CH2(3,5-Me2Pz)2M(CO)3(CNBu-t) (M为Mo或W). 另外, 该化合物与三苯基膦或亚磷酸甲酯及异丙酯反应时, 只发生羰基取代反应得到化合物CH(3,5-Me2Pz)2Mo(CO)2(PR3)SnPh3 (R为苯基、甲氧基及异丙氧基). 而用亚磷酸苯酯与之反应, 除得到羰基取代产物外, 还伴随着P-O/C键的交换, 得到金属钼上还原消除的产物(PhO)2PCH(3,5-Me2Pz)2Mo(CO)3.  相似文献   
2.
针对充放电模式对电极储锂性能的影响开展综合实验研究与机理分析.设计了4种充放电模式,进行不同充放电模式下还原氧化石墨烯电极的储锂性能实验,并从电极动态反应性能和应变两方面开展实验分析充放电模式对储锂时间和容量的影响机理.实验结果显示,不同充放电模式下电极储锂时间越短容量折损越多,综合数据分析指出电荷转移阻抗、扩散系数、过电位和应变均表现出了非线性和阶段性的特点.最后提出“大电流-小电流”模式为可行的充放电优化方案,利用电化学进程的非线性平衡了快充技术中时间和容量之间的矛盾,为快速充电技术的设计和优化提供了一定的指导.  相似文献   
3.
以5种苄氧基/烷氧基苯胺为基础, 设计合成了系列新颖的N-苄氧/烷氧苯基-4,6-二取代嘧啶胺类化合物, 其结构经1H NMR、MS及元素分析确证, 其中化合物5r的单晶结构经X射线单晶衍射分析确证. 油菜平皿法和稗草小杯法测试除草活性结果表明, 4种苄氧基/烷氧基苯胺3a, 3b, 3d, 3e具有较好的除草活性, 在100 μg/mL浓度下对单子叶稗草生长抑制率可达到77.3%—88.5%. KARI活性测试结果表明, 化合物5a—5s有较弱的KARI抑制活性.  相似文献   
4.
The title compound 2-amino-4-chloro-5-(4-methylbenzyl)-6-methylpyrimidine (C26H28Cl2N6, Mr = 495.44) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis. The crystal belongs to monoclinic, space group P21/c with a = 14.892(7), b = 6.129(3), c = 14.889(7) , β = 109.795(8)°, V = 1278.7(10) 3, Z = 2, F(000) = 520, Dc = 1.287 g/cm3, μ = 0.280 mm-1, the final R = 0.0577 and wR = 0.1589 for 1357 observed reflections with I > 2σ(I). A total of 6091 reflections were collected, of which 2257 were independent (Rint = 0.033). The X-ray analysis reveals that the chlorine atom and methyl of the title compound are disordered.  相似文献   
5.
近年来,多齿含氮的配体在有机配合物的合成和研究中日益受到重视,不仅用在高氧化态、缺电子中心的高价过渡金属有机配合物上,而且已开始在低氧化态、富电子中心的低价过渡金属有机配合物上应用,其中一个重要原因是自然界中许多金属酶普遍含有以氮为配位原子的配体.我们合成了N,N'-二(3,5-二甲基吡唑)烷的衍生物1,同时分离得到了一种新型的环状化合物2.  相似文献   
6.
以4-氰基苯酚和2-氯丙酸乙酯(或2-氯乙酸甲酯)为起始原料进行反应,得到2-(4-(1H-四唑-5-基)苯氧基)丙酸/乙酸酯,进而发生Huisgen反应合成了一系列新型1,3,4-噁二唑类标题化合物,其结构经~1H NMR,~(13)C NMR,IR,MS及元素分析或高分辨质谱得到表征和确认.用X射线衍射测定了化合物3q的晶体结构.初步生物活性测试结果表明,含有较小体积取代基的噁二唑化合物3c和3d在200μg/mL测试浓度下对水稻KARI酶分别具有94.5%和83.1%的抑制活性.化合物3p在100μg/mL浓度下对双子叶油菜(Brassica campestris)胚根生长抑制率可达82.4%.  相似文献   
7.
本文研究小分子有机胺辅助长链有机多胺模板剂导向合成过渡金属磷酸盐微孔晶体材料.通过在二乙烯三胺为模板剂的反应体系中添加正丁胺或者正丙胺,合成了一种具有十六元环超大微孔磷酸锌钻晶体材料CoZnPO4-V研究发现,虽然添加两种小分子有机胺都能辅助生成CoZnPO4-V但是它们对于合成体系晶化产物的影响不同,加入正丁胺可以获得该物质的纯相,而正丙胺则有利于生成该物质的高品质大单晶.单晶结构解析结果显示CoZnPO4-V是一种新结构金属磷酸盐.它属于单斜晶系,空间群为P21/c(No.14),晶胞参数为a=31.936(3)A,b=8.3775(7)A,c=15.7874(13)A,α=7=90°,β=97.0530(10)°,V=4191.8(6)A°,Z=4结构解析偏离因子为R1=0.0455,wR2=0.0869.其基本结构单元可以看做为三个共边连接的四元环,称为43单元.此结构单元在垂直于b轴的平面上“顶角”相连形成一条无限长链,长链之间通过四元环连接起来,形成了构建超大微孔的十六元环;沿b轴方向上,43单元之间通过四元环连接形成无限的“之”字型链,从而构筑起CoZnPO4-V的三维骨架结构和十六元环孔道.  相似文献   
8.
The title compounds(Z)-3-(2-(3-chloropyridin-2-yl)hydrazono)indolin-2-one(A) and 7-bromo-(Z)-3-((4-pyridinyl)carboxlichydrazono)-2-indolinone(B) have been synthesized and structurally determined by elemental analysis and single-crystal X-ray diffraction studies.Compound A(C13H8ClN4O) belongs to the orthorhombic crystal system,space group Pca21 with a = 20.799(4),b = 4.9312(10),c = 11.764(2),V = 1206.6(4)3,Mr = 271.68,Dc = 1.496 g/cm3,μ = 0.313 mm-1,F(000) = 556,Z = 4,the final R = 0.0346 and wR = 0.0831 for 2683 observed reflections with I > 2σ(I).Compound B(C14H9BrN4O2) belongs to the triclinic crystal system,space group P1 with a = 6.6834(13),b = 7.0727(14),c = 14.285(3),α = 95.56(3),β = 99.00(3),γ = 102.95(3)°,V = 643.8(2)3,Mr = 345.16,Dc = 1.780 g/cm3,μ = 3.203 mm-1,F(000) = 344,Z = 2,the final R = 0.0487 and wR = 0.1167 for 2334 observed reflections with I > 2σ(I).The preliminary herbicidal bioassay reveals that compounds A and B have some inhibition both in vivo and in vitro against AHAS.  相似文献   
9.
With an aim to discover novel AHAS inhibitors,the title compound (S)-ethyl-2(2-methoxy-phenylsulfenamido)-3-(1H-indol-3-yl)propanoate (C 21 H 22 N 2 O 4 S,M r=398.47) has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction analysis.The crystal belongs to orthorhombic,space group P2 1 2 1 2 1 with a=8.078(2),b=12.824(4),c=18.788(6),V=1946.2(10) 3,Z=4,F(000)=840,D c=1.360 mg/m 3,μ=0.197 mm-1,the final R=0.0433 and wR=0.1035 for 3075 observed reflections with I > 2σ(Ⅰ).The absolute structure Flack parameter X of this compound is 0.00(8).A total of 14375 reflections were collected,of which 3431 were independent (R int=0.0437).X-ray analysis reveals that the crystal structure involves two intermolecular N-H···O and one N-H···S intermolecular hydrogen bonds with the neighboring molecules.The crystal structure was compared with our previously reported (S)-methyl 2-(4-R-phenylsulfonamido)-3-(1H-indol-3-yl)propanoate (R=H(1) and Cl(2)),which provided some useful information of these compounds.  相似文献   
10.
Lithium-ion batteries suffer from mechano–electrochemical coupling problems that directly determine the battery life. In this paper, we investigate the electrode electrochemical performance under stress conditions, where seven tensile/compressive stresses are designed and loaded on electrodes, thereby decoupling mechanics and electrochemistry through incremental stress loads. Four types of multi-group electrochemical tests under tensile/compressive stress loading and normal package loading are performed to quantitatively characterize the effects of tensile stress and compressive stress on cycle performance and the kinetic performance of a silicon composite electrode. Experiments show that a tensile stress improves the electrochemical performance of a silicon composite electrode, exhibiting increased specific capacity and capacity retention rate, reduced energy dissipation rate and impedances, enhanced reactivity, accelerated ion/electron migration and diffusion, and reduced polarization. Contrarily, a compressive stress has the opposite effect, inhibiting the electrochemical performance. The stress effect is nonlinear, and a more obvious suppression via compressive stress is observed than an enhancement via tensile stress. For example, a tensile stress of 675 k Pa increases diffusion coefficient by 32.5%, while a compressive stress reduces it by 35%. Based on the experimental results, the stress regulation mechanism is analyzed. Tensile stress loads increase the pores of the electrode material microstructure, providing more deformation spaces and ion/electron transport channels. This relieves contact compressive stress, strengthens diffusion/reaction, and reduces the degree of damage and energy dissipation. Thus, the essence of stress enhancement is that it improves and optimizes diffusion, reaction and stress in the microstructure of electrode material as well as their interactions via physical morphology.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号