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   81篇
  免费   14篇
  国内免费   32篇
化学   124篇
晶体学   1篇
物理学   2篇
  2023年   1篇
  2022年   3篇
  2021年   6篇
  2020年   6篇
  2019年   4篇
  2018年   4篇
  2017年   4篇
  2016年   6篇
  2015年   5篇
  2014年   8篇
  2013年   21篇
  2012年   5篇
  2011年   7篇
  2010年   4篇
  2009年   5篇
  2008年   5篇
  2007年   5篇
  2006年   2篇
  2005年   4篇
  2004年   2篇
  2003年   3篇
  2002年   2篇
  2000年   2篇
  1997年   1篇
  1996年   3篇
  1995年   4篇
  1993年   4篇
  1991年   1篇
排序方式: 共有127条查询结果,搜索用时 15 毫秒
1.
The new isocyanato carborane anion, [7-OCN-7-CB10H12] was prepared by the reaction of 7-H3N-7-CB10H12 with triphosgene in the presence of triethylamine. The structure of this compound was established by 1H, 11B and 13C NMR as well as IR spectroscopy. The reactivigty of this compound with a series of organic amines was investigated. The resulting ureas were obtained in good to excellent yields. This approach is suitable for development of compounds for use in tumor selective Boron Neutron Capture Therapy (BNCT).  相似文献   
2.
三齿单核三(3,5-二甲基-1-吡唑)硼氢钼配合物Tp*Mo(O)Cl2 (1)(Tp*=三(3,5-二甲基-1-吡唑)硼氢HB(C3H(Me2)N2)3)与含硫族元素碳硼烷的锂盐[(THF)2LiE2C2B10H10(THF)]<  相似文献   
3.
Structural isomers of thermo‐oxidatively stable poly(carborane‐siloxane‐arylacetylene) (PCSAA), namely, m‐PCSAA and p‐PCSAA, were synthesized by the reaction of the dimagnesium salts of m‐diethynylbenzene or p‐diethynylbenzene with 1,7‐bis(chlorotetramethyldisiloxyl)‐mcarborane. The developed polymers have exceptional thermo‐oxidative properties similar to their diacetylene counterpart poly(carborane‐siloxane‐acetylene), PCSA. Thermal treatment of either of the PCSAAs results in a fully crosslinked thermoset by 500 °C resulting from the cycloaddition reactions involving the acetylene and aryl functionalities and subsequent formation of bridging disilylmethylene entities as discerned from Fourier transform infrared, 13C and 29Si solid‐state NMR, and XPS studies. X‐ray diffraction analysis revealed that the thermosets obtained from p‐PCSAA possess enhanced crystallinity when compared to that obtained from m‐PCSAA possibly due to more efficient packing interactions of the p‐diethynylbenzene groups during thermoset formation. The presence of the aryl groups in the backbone of the PCSAAs' chains appeared to have enhanced the storage and bulk moduli of their thermosets when compared to the thermoset of PCSA. Dielectric studies of m‐PCSAA and p‐PCSAA revealed segmental relaxation peaks, α, above their glass transition temperatures with p‐PCSAA exhibiting a broader peak with a slower relaxation rate than m‐PCSAA. © 2013 Wiley Periodicals, Inc.? J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2638–2650  相似文献   
4.
半夹芯16e化合物CpCoS2C2B10H10(Cp:cyclopentadienyl)(1)与2-呋喃炔酮在物质的量比为1:1.5时反应分离得到1个顺磁性化合物CpCoS2C2B10H9(C12H10O2)(2)。在化合物2的合成过程中,一分子1中的Cp环与另一分子1中的B(3)/B(6)位连接;同时,该Cp环与1个2-呋喃炔酮分子发生Diels-Alder反应,生成1个双环[2.2.1]-2-庚烯基结构单元。此外,呋喃炔酮分子中的末端炔基碳原子与原料1中的1个硫原子相连,从而使得产物2中的钴中心离子是个17e中心。化合物2用红外、核磁、元素分析,质谱和单晶X-射线衍射分析等方法进行了表征。晶体属三斜晶系,空间群P1,晶胞参数:a=0.96657(11)nm,b=1.54423(15)nm,c=1.75650(18)nm,α=114.0800(10)°,β=105.433(2)°,γ=98.6390(10)°。  相似文献   
5.
半夹芯16e化合物CpCoS2C2B10H10(Cp:cyclopentadienyl) (1)与HC≡CCO2Me在2-甲基二硫代丙酸存在下反应生成化合物{(C5H4CoS2C2B9H9)(CH=CHCO2Me)(Me2c=CS2H)} (2)和(Me2c=CS2H)3Co (3)。在化合物2中, 原料化合物1中的一个S-Co键断裂, 该S原子与一分子HC≡CCO2Me末端炔基碳原子连接。Co原子与2-甲基二硫代丙酸的S原子连接成键, 2-甲基二硫代丙酸分子中的SH基团与Co原子通过配位键相连;同时, Cp环的一个碳原子与碳硼烷笼体的B(3)/B(6)位相连, 该B(3)/B(6)位的氢原子迁移到炔烃HC≡CCO2Me的内部炔基碳原子上形成反式烯键。3个2-甲基二硫代丙酸分子中的3个S原子分别与1中的Co原子通过共价键连接, 3个SH基团与Co原子通过配位键相连, 从而形成化合物3。化合物23分别用红外、核磁、元素分析、质谱和单晶X-射线衍射分析等方法进行了表征。  相似文献   
6.
邻位碳硼烷分别与正丁基锂、硫粉和Me4CpCo(CO)I2反应合成得到半夹芯16电子碳硼烷化合物Me4CpCoS2C2B10H10 (1).1与二茂铁炔酮在二氯甲烷中反应得到产物{(Me4CpCoS2C2B10H10)[FcC(O)CHCCHCC(O)Fc]} (2)(Fc=二茂铁基).2是一个1:2的加成产物,2个二茂铁炔酮分子以头-尾的方式加成到分子1中的1个Co-S键上.12分别用红外、核磁、元素分析、质谱和单晶X-射线衍射等表征方法进行了结构表征.  相似文献   
7.
A new compound [CpCo(Se2C2BIoH9)CH2C(O)C4H30] has been synthesized and characterized by elemental analysis, IR spectroscopy, NMR, MS and single-crystal X-ray diffraction. The complex crystallizes in the monoclinic system, space group P21/c with a = 10.9481(10), b = 24.6600(12), c = 25.7430(14) A, β = 100.863(3)°, C42H57B30Co306Se6"CH2C12"0.25H20, Mr = 1722.16, V = 6825.6(8) A3, Dc= 1.676 g/cm3, Z = 1 and F(000) = 3346. The molecular structure shows a 1:1 ratio product of the two reactants of 16e half-sandwich complex CpCo(Se2C2B10H10) and alkyne 1-(2-furyl)-2-propyn-l-one. The hydrogen atom in the B(3) position of CpCo(Se2C2B10HIo) has been activated and migrated to the terminal carbon of 1-(2-furyl)- 2-propyn-l-one to form the B-CH2 unit. The title compound molecules are linked and extended further into a one-dimensional chain through atypical hydrogen bonds.  相似文献   
8.
Half-sandwich zirconium complex 3 containing tridentate carborane [S,S,O] ligand 2 [(HOC6H2R2-4,6)(CH2)SC(B10H10) C(Ph)2P=S, R=tBu] was synthesized by the reaction of CpZrCl3(Cp=η5-C5H5) with sodium salt of ligand 2. Zirconium complex 3 was characterized by elemental and NMR analyses. DFT calculations were also performed on complex 3 to analyze the stereochemistry. The results from DFT calculations indicate that structure S1, in which no sulfur atom bonds to the zirconium atom, exists at the lowest energy level. In the presence of methylaluminoxane(MAO), complex 3 exhibited good catalytic activities for ethylene polymerization and long life-time up to 10 h. Moreover, the complex 3/MAO system displayed excellent catalytic activities toword ethylene copolymerization with 1-hexene or polar olefins.  相似文献   
9.
半夹芯16电子碳硼烷化合物Cp~*CoS_2C_2B_(10)H_(10)分别与二苯基甲基膦、苯基二甲基膦和三甲基膦反应得到碳硼烷衍生物(Cp~*CoS_2C_2B_(10)H_(10))(PPh_2Me)(1)、(Cp~*CoS_2C_2B_(10)H_(10))(PPhMe_2)(2)和(Cp~*CoS_2C_2B_(10)H_(10))(PMe_3)(3)。分别用红外、核磁、元素分析、质谱和单晶X射线衍射等表征方法对1、2和3进行了结构表征。紫外可见吸收光谱结果显示化合物1、2和3在乙腈溶剂中均有2个吸收峰,第一个吸收峰分别位于321、316和321 nm;第二个吸收峰分别位于425、399和407 nm。荧光光谱结果显示化合物1、2和3在乙腈中的最大发射波长位于406 nm左右。  相似文献   
10.
New phosphorus‐containing, five‐membered P,P,P and P,N,P heterocycles were synthesized and fully characterized. The P,P,P heterocycles, 1,2,3‐triphospholanes, can be synthesized by two different facile pathways, whereas the P,N,P compound, a 1‐aza‐2,5‐diphospholane, can only be obtained with silylamine.  相似文献   
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