1,2,3-三唑二羧酸镉(II)配位聚合物的合成、晶体结构与性质

利用低温水热法合成了两个新的镉配位聚合物:[Cd(L1)(H2O)2]n(1)和[Cd(L2)(H2O)]n(2)(H2L1=1-羧甲基-4-(2-羧甲氧基苯基)-2H-1,2,3-三唑,H2L2=2-羧甲基-4-(2-羧甲氧基苯基)-2H-1,2,3-三唑,利用X-射线单晶衍射、红外光谱、核磁共振(1H NMR)、元素分析、X-射线粉末衍射和热重分析对配体和配位聚合物进行了表征.晶体结构分析表明配位聚合物1和2为二维结构;两种完全去质子化的配体以μ4为配位模式分别与镉离子形成二维配位聚合物,配位聚合物1呈现双节点(4,4)连接的{44·62}拓扑结构,配位聚合物2则呈现{43·63}拓扑结构.同时,在室温下研究了配体和配位聚合物的固体荧光性质.     

以1,2,5-噻二唑-3,4-二酸为配体的碱土金属配合物的合成、晶体结构及配位模式

以1,2,5-噻二唑-3,4-二酸为单一配体与第二主族碱土金属离子通过水热法合成了三个配合物,对其进行了元素分析及单晶衍射结构解析,并对H2tdzdc配体的配位能力、配位模式等特性作了初步研究.结果表明:单核配合物1,[Mg(tdzdc)(H2O)4]属于三斜晶系,空间群为P1;配位聚合物2,[Ca(tdzdc)(H2O)2]n,具有二维层状结构,属于单斜晶系,空间群为C2/c;配位聚合物3,[Sr(tdzdc)(H2O)3]n,具有二维层状结构,属于三斜晶系,空间群为P1.通过研究发现,当使用ⅡB主族的碱土金属与1,2,5-噻二唑-3,4-二酸根进行配位时,随着金属离子半径的增加和电子层数的增多,金属离子的配位数增多,得到的Mg、Ca、Sr的配合物结构愈加复杂,即从单核配合物到配位聚合物.     

一维梯状配位聚合物[Cd(nic)(bdc)0.5(H2O)2]n· 2nH2O的合成及表征

此文介绍一个一维梯状镉配位聚合物[Cd(nic)(bdc)0.5(H2O)2]n·2nH2O(1)(Hnic=烟酸,H2bdc=1,4-苯二甲酸),并通过X-射线单晶衍射、元素分析、红外光谱、热重分析对其结构进行表征.梯形梯框为[Cd(nic)(H2O)2]+链,梯级为bdc2-配体.梯状长链通过氢键相互作用连接形成三维超分子网状结构,在室温下,聚合物1显示蓝色荧光性能.     

两例Ni(Ⅱ)/Cu(Ⅱ)配位聚合物的合成、晶体结构及热稳定性研究

在溶剂热的条件下,合成了两例金属-有机配位聚合物:{[Ni(H2O)2(1,3-BIP)2]·TFBDC}n(1)和{[Cu3(H2O)4(1,3-BIP)6]·(BTC)2·(H2O)15}n(2)(1,3-BIP为1,3-二(咪唑)丙烷,H2TFBDC为2,3,5,6-四氟对苯二甲酸和H3BTC为1,3,5-均苯三酸),并利用红外光谱、元素分析和X-射线单晶衍射等技术手段对其结构进行了表征.X-射线单晶衍射结果表明配位聚合物1呈现一维环形链构型,并通过分子间氢键作用进一步连接形成三维超分子网络结构.配位聚合物2呈现出(4,4)拓扑的二维层状结构.此外,研究了两例配位聚合物的热稳定性能.     

锌(Ⅱ)配位聚合物{[Zn(CPGA)(DPPP)]H2O}n的合成和晶体结构

采用水热法合成了一个锌的新型配位聚合物{[Zn(CPGA)(DPPP)]·H2O｝n(1),[CPGA=3-(4-氯苯基)戊二酸根,DPPP=l,3-二(4-吡啶基)丙烷],用元素分析、红外光谱和X-射线单晶结构等进行了表征.结果表明该配位聚合物属于单斜晶系,P21/n空间群.晶胞参数为:a=1.3775(2) nm,b=1.20745(19) nm,c=1.4854(2) nm,F(000)=1080,Dc=1.419 g·cm-3,V=2.4446(7) nm3,Mr=522.28,Z=4,μ=1.151 mm-1,月1=0.0389,ωR2=0.1253.该配位聚合物晶体中,Zn(Ⅱ)与配体3-(4-氯苯基)戊二酸根和DPPP连接形成一维波浪面结构,水分子和3-(4-氯苯基)戊二酸根中未参与配位的氧原子形成的氢键将相邻的两层连接形成双层结构,双层结构没有进一步连接.     

配位聚合物{[Cd(pda)(4,4'-bipy)(H2O)]·H2O}n的合成、晶体结构与荧光性质

在水热条件下利用间苯二乙酸,4,4'-二联吡啶和硝酸镉反应生成配位聚合物{[Cd(pda)(4,4'-bipy)(H2O)]·H2O｝n(1)(1,3-H2pda=间苯二乙酸、4,4'-bipy=4,4'-二联吡啶).其晶体结构采用红外光谱、热重分析及单晶X射线衍射等手段进行了表征.结构分析表明该配位聚合物属三斜晶系,空间群为Pī;晶体学参数:a=0.7991(4)nm,b=1.1514(5) nm,c=1.2075(5) nm;α=107.352(6)°,β=97.505(6)°,γ=108.925(6)°,V=970.8(8) nm3.其基本结构单元由两个Cd(Ⅱ)离子、两个间苯二乙酸根、四个4,4'-二联吡啶、两个水分子组成.有趣的是所有的闭合环[Cd2(pda)2]通过两线状4,4 '-二联吡啶支撑连接形成一维管状配位聚合物.同时对该配位聚合物的荧光性质进行研究,发现在366 nm处呈现较强的荧光发射(λex=300 nm).     

水热合成三维超分子配位聚合物[Cd(C2O4)(H2O)2]·H2O及晶体结构

在水热条件下,制备了二维层状配位聚合物 [Cd(C2O4)(H2O)2] ·H2O(1)的单晶体,对其进行了X射线粉末衍射、元素分析、红外光谱、热重分析和X射线单晶衍射测定.单晶结构分析表明,该晶体属于三斜晶系,P-1空间群,晶胞参数a=0.60109(12)nm, b=0.66607(13)nm,c=0.84987(17)nm,α=74.72(3)°,β=74.33(3)°,γ=81.07(3)°,V=0.31473(11)nm3,Z=2,R1=0.015,ωR2=0.0368.草酸镉单晶结构由两个2D层构成,每一个2D层是由[Cd2(C2O4)2(H2O)4]·2H2O的重复单元形成,每个单元是由一个七配位独立镉原子配位而成(五个草酸氧原子和两个水分子氧原子).2D层与层之间通过不同层草酸分子与配位水分子之间及草酸与客体水分子之间形成的氢键将2D层状化合物连成一个3D超分子结构.热重分析表明该配位聚合物在340℃下稳定.     

基于4-(1H-吡唑-3-基)-吡啶构筑的新型Zn(Ⅱ)配位聚合物的合成、晶体结构和性质研究

采用水热法,合成了一个Zn(Ⅱ)配位聚合物[Zn3(4-PP)4(OH)2(SO4)2(H2O)2]n(1,4-PP=4-(1H-pyrazol-3-yl) pyridine),并用元素分析、红外光谱和X-射线单晶衍射对其进行了表征,测定了其热重性质和荧光性质.该配位聚合物1属于单斜晶系,P21/c群,其晶胞参数为:a=12.303(3) nm,b =6.0083(12) nm,c=25.308(5) nm,β=101.40(3)°,F(000)=1056,Dc=1.882 g/cm3,V=1833.8(6) nm3,Mr=1038.94,Z=2,μ(MoKα)=2.140 mm-1,R1=0.0672,wR2 =0.1300.在该配位聚合物1中,金属锌(Ⅱ)与SO24-以及OH-形成纯无机的二维层状结构,而4-PP配体仅作为端基配体;二维结构进一步通过氢键的作用形成三维超分子结构.     

具有蓝光性能的二维Zn~Ⅱ配位聚合物的合成、晶体结构和光谱性质研究(英文)

在水热条件下,合成了一个二维配位聚合物{[Zn2(L)(m-bix)]2·0.5(H2O)}n[H4L=5,5'-亚甲基二间苯二甲酸,m-bix=1,3-双(咪唑基-1-甲基)-苯],并通过红外和X-射线单晶衍射进行了表征。X-射线衍射结果表明,该配位聚合物晶体属于三斜晶系,P-1空间群,a=1.10294(17)nm,b=1.10806(15)nm,c=1.2605(2)nm,α=73.259(2)°,β=74.304(3)°,γ=67.576(2)°,V=1.3410(4)nm3,Z=1。配位聚合物中,Zn(II)原子采取四面体构型,三个氧原子分别来与三个L4-配体,一个氮原子来于配位的m-bix分子。每个L4-配体桥联六个Zn(II)中心,形成一个波浪状的二维面[Zn2(L)]∞,然后m-bix分子在[Zn2(L)]∞的上下方连结双核Zn(II)单元,形成二维层状化合物[Zn2(L)(m-bix)]∞。室温下研究了配位聚合物的固体荧光光谱特性。     

1,3-间苯咪唑及间苯二甲酸根一维镍(Ⅱ)配位聚合物的合成、晶体结构及性质

以间苯咪唑(1,3-bib)和间苯二甲酸(H2MPA)为配体,采用水热法合成了1个一维镍(Ⅱ)配位聚合物[Ni(1,3-bib) (MPA)·2H2O]n(1).并对该配位聚合物进行了元素分析、红外光谱、固体紫外、热重(TGA)和Ⅹ-射线粉末衍射(PXRD)等表征,并用Ⅹ-射线单晶衍射法测定了它的单晶结构.该配位聚合物属于正交晶系,Pnma空间群,为一维结构.室温下固体紫外测试结果显示,配位聚合物具有强的紫外吸收.     

Calculation of phase diagrams in AlxIn1−xAs/InP,AsxSb1−xAl/InP and AlxIn1−xSb/InSb nano-film systems

The models for calculation of phase diagrams of semiconductor thin films with different substrates were proposed by considering the contributions of strain energy, the self-energy of misfit dislocations and surface energy to Gibbs free energy. The phase diagrams of the Al_xIn_1−xAs and As_xSb_1−xAl thin films grown on the InP (1 0 0) substrate, and the Al_xIn_1−xSb thin films grown on the InSb (1 0 0) substrate at various thicknesses were calculated. The calculated results indicate that when the thickness of film is less than 1 μm, the strain-induced zinc-blende phase appears, the region of this phase extends with decreasing of the layer thickness, and there is small effect of surface energies of liquid and solid phases on the phase diagrams.     

Elastic properties of GexAsySe100−x−y glasses

The elastic properties of Ge_xAs_ySe_100−x−y (0x30; 10y40) glasses have been studied. The results were analyzed in terms of the dependence on the theoretical mean coordination number (mean number of covalent bonds per atom) m (m=2+(2x+y)×0.01). Three ranges of m (2.1m2.51, 2.51<m2.78, 2.78<m3) were revealed, where different dependencies of elastic moduli (Young’s modulus, shear modulus) and Poisson’s ratio of glasses on m were observed.     

Crystal growth of NdAl3(BO3)4 from K2O/MoO3/Nd2O3/B2O3/KF flux

NdAl₃(BO₃)₄ single crystals were grown by the flux method and the TSSG technique using a K₂O/3MoO₃/B₂O₃/0.5Nd₂O₃/KF flux system. Light-violet clear crystals could be obtained. The effects of fluoride on the growth of NAB crystals were investigated. As the content of KF was gradually increased, the growth form of NAB was changed from the equant to the columnar and the primary crystalline region of NAB was shrinked. At the ratio of KF/K₂O = 0.75, NAB crystals could not be grown.     

Synthesis and structure of new phases of the Am?1Bi2BmO3m+3 (m = 2) type

Three polycrystalline bismuth-containing layered perovskite-like oxides are synthesized by high-temperature solid-state reactions. One of these compounds was described previously, namely, Bi₃Ti_1.5W_0.5O₉, for which the unit cell parameters a = 5.372(5) Å, b = 5.404(4) Å, and c = 24.95(2) Å are determined in this study. The other two compounds, namely, Na_0.75Bi_2.25Nb_1.5W_0.5O₉ with the unit cell parameters a = 5.463(1) Å, b = 5.490(7) Å, and c = 24.78(0) Å and Ca_0.5Bi_2.5Ti_0.5Nb_1.5O₉ with the unit cell parameters a = b = 3.843(2) Å and c = 24.97(6) Å, are synthesized for the first time. The compositions of these compounds are based on the composition of the well-known compound Bi₃TiNbO₉ with a high Curie temperature (T _C = 1223 K), in which bismuth, niobium, and titanium atoms are partially or completely replaced by other atoms. The experimental and calculated interplanar distances determined from the X-ray diffraction patterns of the studied compounds are presented. __________ Translated from Kristallografiya, Vol. 50, No. 1, 2005, pp. 59–64. Original Russian Text Copyright ? 2005 by Geguzina, Shuvaev, Shuvaeva, Shilkina, Vlasenko.     

Vapour epitaxial growth and characterization of InAs1-xPx

The vapour growth of InAs_1-xP_x layers has been carried out by the hydride process. The phosphorus rich part of the system (0.7 ? x ? 1) was especially investigated. Heteroepitaxial deposits of InAs_1-xP_x and InP have been performed on substrates such as InAs, GaAs and GaP. A systematic study of the influence of the substrate orientation on the quality of the layer has been carried out by growth on hemispherical substrates. Preferential planes have been pointed out: (100) and (111) A for InAs, (111) for GaAs and GaP. The band gap variation as a function of the composition has been determined by photoluminescence at 4.2 °K and X-ray diffraction measurements. It fits the equation: E_G(x) eV = 0.425 + 0.722 x + 0.273 x² at 4.2 °K.     

Crystallization behaviours ofCo100−1(x+y)NbxBy amorphous alloys

The crystallization behaviours of Co_100?1(x+y)Nb_xB_y amorphous alloys were investigated by means of differential thermal analysis and a conventional X-ray diffractometer. The crystallization sequences are discussed in terms of the equilibrium phase diagram of the ternary alloy system.Assuming crystallization occurs as a result of nucleation and growth, the stabilizing effect of eutectic phase separation on the crystallization is shown by introducing the effective free energy of the critical nucleus.     

Precipitation of In2O3 nano-crystallites from glasses in the system Na2O/B2O3/Al2O3/In2O3

Glasses in the system Na₂O/B₂O₃/Al₂O₃/In₂O₃ were melted and subsequently tempered in the range from 500 to 700 °C. Depending on the chemical composition, various crystalline phases were observed. From samples without Al₂O₃, In₂O₃ could not be crystallized from homogeneous glasses, because either spontaneous In₂O₃ crystallization occurred during cooling, or other phases such as NaInO₂ were formed during tempering. The addition of alumina, however, controlled the crystallization of In₂O₃. Depending on the crystallization temperature applied, the crystallite sizes were in the range from 13 to 53 nm. The glass matrix can be dissolved by soaking the powdered glass in water. This procedure can be used to prepare nano-crystalline In₂O₃-powders.