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   11篇
  免费   1篇
  国内免费   4篇
化学   15篇
物理学   1篇
  2024年   1篇
  2021年   1篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2017年   1篇
  2015年   1篇
  2014年   3篇
  2013年   1篇
  2011年   1篇
  2010年   1篇
  2007年   1篇
  2002年   1篇
排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
A new manganese coordination polymer(CP)has been synthesized under hydrothermal conditions.It’s formula is{Mn2(Oaobtc)(bpe)(H2O)4]}n,where H4Oobtc represents oxide azobenzene 2,2',3,3'-tetracarboxyl acid,and bpe is 1,2-bis(4-pyridine)ethylene.It was characterized by elemental analysis,infrared spectrum and X-ray single-crystal diffraction.The coordination polymer crystallizes in the monoclinic system,space group P21/c.The central ion was coordinated with H4Oobtc ligands using bridging model,and carboxylic group connects two adjacent Mn(Ⅱ)ions into dimer units.The oxygen from carboxylates connect these dimer units into a one-dimensional(1D)chain,and N atoms from the bpe further expanded them into three-dimensional(3D)supramolecular edifice,eventually.Variable-temperature magnetic measurements of CP 1 indicate the presence of weak antiferromagnetic exchange between two nearest Mn(Ⅱ)ions with J=–0.367 cm-1.  相似文献   
2.
合成了2个基于氮氧自由基配体且结构类似的双核配位化合物,其分子式分别为[Mn2(hfac)4(NIT-mo-pmy)2](1)和[CO2(hfac)4(NIT-mo-pmy)2](2),其中hfac=六氟乙酰丙酮,NIT-mo-pmy=2-(2-甲氧基-5′-嘧啶基)-4,4,5,5-四甲基咪唑啉基-3-氧-1-氧自由基。2个配合物均属于三斜晶系P1空间群,其双核配位单元进一步构筑为中心对称的平行四边形分子阵列。变温磁化率的测试表明,在2个配合物中,中心离子和氮氧自由基单元之间存在反铁磁交换作用。借助构效关系研究,分析了磁作用强度的差异。通过适当近似的磁化学模型,对Mn(Ⅱ)配合物的磁性行为进行了定量拟合,并与相关化合物磁作用强度进行了比对、分析。  相似文献   
3.
A new lanthanum coordination polymer formulated as {[La2(pyda) 2(μ4-SO4) ·5H2O]· 2H2O}n(1,H2pyda = 2,6-pyridine-dicarboxylic acid) has been synthesized from the reaction of H2pyda with lanthanide nitrate in the presence of sulfate as a counter anion. The compound was characterized by elemental analysis,IR spectroscopy and X-ray single-crystal diffraction. It crystallizes in the orthorhombic system,space group Pna21,with a = 18.8558(19) ,b = 6.5831(7) and c = 18.7543(19) . The compound is a 2D hybrid,in which the La(Ⅲ) ions were doubly connected by the carboxylic group of pyda2-ligand to form the La(Ⅲ) dimer followed by being grafted into 1D zig-zag chains which are further connected into a 2D network containing {[La(SO4) ]+}n helical chains. The interchain hydrogen bonding and π-π stacking interactions extended the 2D networks into a 3D supramolecular edifice.  相似文献   
4.
A d-f heteronuclear metal-organic framework(MOF),{[Tm_3Zn_6(bipy_2)_2(mimda)_7(H_2O)_3]·(H_2O)_5}_n(1,H3 mimda = 2-methyl-1-H-imidazole-4,5-dicarboxylic acid,and bipy = 4,4?-bipyridine),has been synthesized under solvothermal conditions,and structurally characterized by elemental analysis,IR spectra and X-ray single-crystal diffraction.It crystallizes in orthorhombic system,space group Pnma with a = 16.1102(9),b = 33.5805(19),c = 16.8593(10) ?,β = 97.344(11)°,V = 9120.7(9) ?~3,Z = 4,F(000) = 5184,the final R = 0.0530 and w R = 0.1306.In complex 1,the Tm(Ⅲ) ions adopt two types of coordination fashions.Complex 1 shows onedimensional(1-D) Tm-Zn heteronuclear zigzag chains,and these chains are further linked by H3 mimda ligands into Tm-Zn heteronuclear 2-D lattice-like arrays.The 2-D heteronuclear units were connected through [Zn_6(mimda)_6] rings to give rise to the Tm-Zn heteronuclear cages.Finally,H3 mimda ligands connected the cages into a 3-D heterometallic framework by the combination of [TmO_7]_n and Tm-Zn heteronuclear cages.In addition,the thermal stability and luminescent property have been investigated.  相似文献   
5.
We study the microlaser in an optical standing-wave cavity injected with two-level atoms.The results have shown the obvious influence of atomic centre-of-mass motion on the microlaser,such as the photon distribution,the linewidth and the frequency shift.It was found that when the momentum of atoms is comparable to that of photons,the influence of atomic motion is dominated and the number of photons in the microlaser can be greatly enhanced,owing to part of the atomic kinetic energy being transferred to the resonator.This work provides a comparison of the related studies on the atomic motion under special assumptions.  相似文献   
6.
通过溶剂热合成了一个新的由2-羟基-6-甲基-异烟酸和草酸混合配体构筑的镝有机框架化合物,化学式为{[Dy(μ2-H2minca)(μ2-C2O4)·2H2O]·H2O}n,(其中,H3minca代表2-羟基-6-甲基-异烟酸).标题化合物呈现复杂的二维(2D)瓦楞状网络63拓扑结构,其中{DyO8}多面体是通过苯羧酸上的羧基和草酸联成片状结构.光致发光研究表明,标题化合物在可见光区域发射出Dy的特征f-f跃迁荧光光谱.热重和差热分析表明,该化合物具有较高的热稳定性.变温磁化率测量表明,相邻镝(Ⅲ)中心之间有可能存在弱的铁磁相互作用.  相似文献   
7.
A new cobalt(II) complex [Co(NO2-salen)2]·1.5H2O containing mono acetalization Schiff base ligand(NO2-salen = N-5-nitro-salicylideneamino ethanato) has been prepared through one-pot template condensation, and has been structurally characterized by elemental analysis, IR spectra and X-ray diffraction. It is formulated as C18H23CoN6O7.5, crystallizes in the hexagonal system, space group of R-3c with α = 25.895(18), b = 25.895(18), c = 35.075(6), γ = 120o, V = 20368(3) and Z = 36. The ligand of 5-nitrosalicylaldehyde-ethylene-diamine takes unusual mono asymmetry mode. The Co(II) ion exhibits a coordination number of six, and assumes a distorted octahedral geometry with a N2O4 donor set. The neutral monomeric units of [Co(NO2-salen)2]·1.5H2O are linked into a one-dimensional(1D) structure via the intermolecular hydrogen bonds and weak π-π stacking interactions. Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are irreversible in nature.  相似文献   
8.
Reaction of 3,5-pyridine-dicarboxylic acid(3,5-PydcH2) with iron salt in hydrothermal condition results in the formation of a three-dimensional self-assembly network formulated as [C14H14Fe2N2O12]n,and it has been structurally characterized by elemental analysis,IR spectra and X-ray diffraction.It crystallizes in the monoclinic system,space group C2/c with a=9.9633(15),b=12.0942(18),c=7.4297(11) and β=105.822o.The units of Fe2(pydc)2·2H2O are linked into a one-dimensional structure via the chelate carboxylate groups from the 3,5-pyridine-dicarboxylate.The interlayer hydrogen bonding interactions result in a three-dimensional supramolecular architecture.In the complex,the Fe(Ⅲ) ion displays a slightly distorted pentagonal bipyramidal geometry with seven coordination numbers.Cyclic-voltammetry measurement reveals the oxidation and reduction processes for the complex are quasi-reversible in nature.  相似文献   
9.
李进  冯勋  郭辉 《应用化学》2017,34(1):0-0
以十二烷基苯磺酸(DBSA)和钨酸钠为原料,在无其它辅助剂条件下,通过水热方法制备了由纳米棒组装成的三维多级微结构WO3·0.33H2O。 结果表明,反应原料DBSA不仅在反应中提供氢离子,而且还具备表面活性剂调控产物形貌的作用。 在可见光照射下,由于其特殊的多级结构,WO3·0.33H2O展现出较强的光催化降解罗丹明B活性,降解率达100%,重复使用5次后,降解率仍保持较高水平。  相似文献   
10.
合成了2个基于氮氧自由基配体且结构类似的双核配位化合物,其分子式分别为[Mn2(hfac)4(NIT-mo-pmy)2](1)和[Co2(hfac)4(NIT-mo-pmy)2](2),其中hfac=六氟乙酰丙酮,NIT-mo-pmy=2-(2-甲氧基-5′-嘧啶基)-4,4,5,5-四甲基咪唑啉基-3-氧-1-氧自由基。2个配合物均属于三斜晶系P1空间群,其双核配位单元进一步构筑为中心对称的平行四边形分子阵列。变温磁化率的测试表明,在2个配合物中,中心离子和氮氧自由基单元之间存在反铁磁交换作用。借助构效关系研究,分析了磁作用强度的差异。通过适当近似的磁化学模型,对Mn (Ⅱ)配合物的磁性行为进行了定量拟合,并与相关化合物磁作用强度进行了比对、分析。  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