熔体温度对负离子配位多面体生长基元聚集体结构的影响

据Na2SiO3与BaB2O4晶体和熔体的高温拉曼光谱测试结果综合分析后提出:熔体的温度对负离子配位多面体生长基元相互联结的聚集体结构有影响.在高温熔体中,高电价、离子半径小的阳离子配位多面体往往孤立存在.当熔体过冷度大时,孤立的负离子配位多面体顶角上的氧与低电价、离子半径大的阳离子配位构成大维度的聚集体.同质异构晶体的熔体拉曼谱都显示出相同的孤立负离子配位多面体振动峰.     

二维异核铜-钠配位聚合物的合成和晶体结构

合成了铜-钠混合金属配位聚合物 [(CuL)2(CH3OO)Na(H2O)4]2 (简写为1)并进行了元素分析和单晶X射线衍射分析,L为{2-(2′-酚基)- Δ 2-噻唑-4-羧酸}.晶体结构分析表明配合物形成Cu4Na2的六核混合金属大环.相邻的Cu4Na2环之间通过进一步的配位作用连结成包含更大的Cu8Na4大环的二维网状结构.该晶体属于三斜晶系Pī空间群,晶胞参数分别为:a = 1.0777(4) nm, b = 1.5221(6) nm, c = 1.6994(6) nm, α = 84.58(1)°, β = 76.31(1)°, γ = 89.97(1) °, V = 2.696 (2) nm3, Z = 2, Mr= 1447.26, dc = 1.783 g·cm-3, T = 293(2) K, μ = 1.816 mm-1, F(000) = 1472, R1 = 0.0794, wR2 = 0.1819 [I>2σ(I)].     

Synthesis and Characterization of Silica Aerogel-Polymer Hybrid Materials

Abstract

Silica aerogel-based hybrid composites containing three different polymers such as poly(styrene) (PS), poly(methyl methacrylate) (PMMA), and PS-co-PMMA were synthesized by two steps: sol-gel reaction to form vinyl silica aerogels and radical polymerization to combine the silica aerogels with the polymers. The reactions were confirmed using FTIR and FE-SEM, showing successful polymerization in the surface of the silica aerogel network. Incorporation of the polymers into the silica aerogel allows for the enhancement of thermal stabilities. From dielectric measurement, the polymer hybridization leads to an increase in the static dielectric constant, compared to bare silica aerogel.     

一维无机-有机杂化材料[Ni(2,2'-bipy)2]V2O6的水热合成与晶体结构

本文采用水热合成法制备了一维无机-有机杂化材料[Ni(2,2'-bipy)2]V2O6(1).反应起始原料摩尔配比为:Ni(Ac)2·H2O:NaVO3:H3BO3:B2O3:2,2-联吡啶:H2O=0.5:1:2.3:2:1.5:556.l属单斜晶系,P21/c空间群,晶胞参数:a=1.4482(3)nm,b=1.3747(3)nm,c=1.0456(2)nm,β=100.25(3)°,V=2.0484(7)nm3,Z=4.1是由VO4四面体通过共顶点联接构成一维链状结构.相邻链的2,2'-bipy分子的π-π相互作用对1分子的结构稳定起到重要的作用.     

一维无机-有机杂化材料[Ni(2,2'-bipy)_2]V_2O_6的水热合成与晶体结构

本文采用水热合成法制备了一维无机-有机杂化材料[Ni(2,2'-bipy)2]V2O6(1)。反应起始原料摩尔配比为:Ni(Ac)2.H2O:NaVO3:H3BO3:B2O3:2,2'-联吡啶:H2O=0.5:1:2.3:2:1.5:556。1属单斜晶系,P21/c空间群,晶胞参数:a=1.4482(3)nm,b=1.3747(3)nm,c=1.0456(2)nm,β=100.25(3)o,V=2.0484(7)nm3,Z=4。1是由VO4四面体通过共顶点联接构成一维链状结构。相邻链的2,2'-bipy分子的π-π相互作用对1分子的结构稳定起到重要的作用。     

基于构象灵活的N-杂环配体构筑的3D拟卤化亚铜配合物的合成、结构和性质研究

溶剂热条件下,通过无机阶梯状链[Cu(SCN)]_n与柔性有机配体1,3-二(4-吡啶基)丙烷(bpp)自组装,得到了一例新型的3D有机-无机杂化配合物[Cu₄(SCN)₄(bpp)₂]_n (1)。值得关注的是,不对称单元中的bpp配体显示两种不同的构象(trans-gauche或trans-trans),并连接梯形的[Cu(SCN)]_n链形成结晶学独立的[Cu₂(SCN)₂(bpp)]_n (A和B)层。紧接着, 两个不同的层通过ABB′A′的顺序排列形成独特的三维褶皱结构。进一步对配合物1进行了红外光谱(FT-IR)、粉末衍射(PXRD)、热分析、固体紫外-可见漫反射光谱(UV-Vis)和光致发光性质研究。固体紫外-可见光谱表明配合物在紫外区有强的吸收并且具有半导体性质,带隙能E_g为3.20 eV。光催化性能测试结果表明,配合物1在紫外光照射下对中性红(NR)、甲基橙(MO)、天青I(AI)、亚甲基蓝(MB)和亮蓝(ED)这五种染料表现出不同的光催化活性,这可能与有机染料的尺寸和电荷差异有关。此外,荧光测试表明配合物在室温下表现出较强的绿色发光性质,在525 nm附近有强的荧光发射峰。这种发射可能与配体中心激发态有关,可能涉及金属到配体或配体到配体的电荷转移。     

Copper(II) and lead(II) complexes of 4,4′-bipyridine-<Emphasis Type="Italic">N,N</Emphasis>′-dioxide

Cu(II) and Pb(II) complexes of 4,4′-bipyridine-N,N′-dioxide have been prepared using a solvent-layering system. [Cu₂Cl₄(bpdo)₃(H₂O)₂] . 2(CH₃)₂SO (1) crystallises in P-1, a=8.731(2), b=8.943(2), c=14.408(3) ?, α=102.85(3), β=97.49(3), γ=109.77(3)°. The Cu(II) complex is a z-shaped discrete molecule with a DMSO molecule hydrogen bonded to the host through coordinated water molecule. Crystallisation of PbCl₂, PbBr₂ and PbI₂ with bpdo afforded isostructural 2D coordination polymers. [PbCl₂(bpdo)]_n is monoclinic, C2/c with a=16.3274(7), b=4.0708(1), c=18.6146(8) ?, β=93.73(1)°; [PbBr₂(bpdo)]_n is monoclinic, C2/c with a=16.403(3), b=4.2412(8), c=18.846(4) ?, β=92.59(3)° and [PbI₂(bpdo)]_n is monoclinic, C2/c with a=16.438(3), b=4.538(1), c=18.973(4) ?, β=91.04(3)°. The adjacent metal centres of these polymers are bridged by coordinated Cl⁻, Br⁻ or I⁻ anions as well as by bpdo ligands. These polymers possess no conventional hydrogen bonds.     

Difficulties in the growth and characterization of non-linear optical materials: A case study of salts of amino acids

In the crystallographic literature, there is an ever-increasing number of publications on crystals that are referred to as ‘new non-linear optical materials’, many of them reporting salts of amino acids. However, the term NLO material is used improperly in most cases. In fact, the establishment of any crystal species as such a material requires several experimental and computational procedures, which are seldom satisfied when characterizing a supposedly new species. Here, some frequent hazards and problems are addressed and observations of papers reporting amino acid compounds as supposedly new NLO materials are made.     

A Novel Three Dimensional Organic–Inorganic Hybrid Based Porous Phase: Synthesis and Characterization of Reduced Oxovanadium pyromellitate, [VIV2O2(H2O)2(C6H2(COO)4)]

The hydrothermal reaction of a mixture of VOSO₄ · xH₂O, 1,2,4,5-benzenetetracarboxylic acid (pyromellitic acid) and 0.1 M H₂SO₄ for 72 h at 160 °C gives blue needle like crystals of [V^IV ₂O₂(H₂O)₂(C₆H₂(COO)₄)] in 30% yield. The compound has a porous 3-D extended network structure having a rigid architecture which is held together by the multidentate functionalities of 1,2,4,5-benzenetetracarboxylate ligand. Crystal data for the compound: monoclinic space group C 2/c (No:15), a = 11.756(5) ?, b = 9.645(3) ?, c = 11.822(7) ?, β = 107.10(4)°, Z = 8. The compound constitutes the first example of a fully reduced oxovanadium based solid incorporating the organic ligand. This article consists of synthesis, crystal structure and characterization of [V^IV ₂O₂(H₂O)₂(C₆H₂(COO)₄)].     

[KCl<Subscript>3</Subscript>{H<Subscript>2</Subscript>dabco}]: A Unique 3-D Charge-Assisted Hydrogen-Bonded Hybrid Network of Anionic KCl<Subscript>3</Subscript> Chains and Organic Cations

Abstract  The 3-D hybrid network [KCl₃{H₂dabco}] resulted from the assemblage of KCl and [{H₂dabco}Cl₂] (1,4-diazabicyclo[2.2.2]octane) in H₂O. The compound crystallizes in the trigonal space group R-3c with a = b = 16.0437(2) Å, and c = 22.3094(2) Å. The structure consists in polymeric chains of anionic {KCl₃}²⁻ linked to {H₂dabco}²⁺ units by hydrogen bonds. Each organic cation establishes such charge-assisted H···Cl interactions with two inorganic arrays leading to a 3-D network. Index Abstract  Assemblage of KCl and [{H₂dabco}Cl₂] (1,4-diazabicyclo[2.2.2]octane) in H₂O resulted in a 3-D hybrid network of inorganic {KCl₃}²⁻ chains H-bonded to bridging organic cations.      

Crystal Engineering: A Unique Cyclic Assembly of a 40 Membered Module Composed from Two Alternating Units Each of Benzenehexacarboxylic Acid (Mellitic Acid,MA) and 2,5-Bis-(4-pyridyl)-1,3,4-oxadiazole (4-BPO): Assembly of Modules to Macromolecules by Intermolecular Hydrogen Bonding

Abstract  Individually prepared, equivalent amounts of 2,5-bis-(4-pyridyl)-1,3,4-oxadiazole (4-BPO) and benzenehexacarboxylic acid (mellitic acid, MA) when mixed, deposited long rods, whose X-ray structure showed a unique assembly of 40 membered planar modules composed from two alternating units each of MA and 4-BPO, rather than the anticipated helical profile. Several novel features of complexes of MA with organic molecules are seen here. In almost all cases the intermolecular hydrogen bonding between MA anions is so stable that the MA anions and the complementary cations lie in separate planes. This barrier is overcome in the present case. The basic module associates to form quartets by very simple hydrogen bonding of the carboxylic groups of MA. The quartet assembly is characterized by the rotation of the left hand pair compared to the right hand pair. The mode of the macromolecular assembly is clear, that is, they are layered in alternating planes. Space group: P2₁/c with a = 9.181(1) ?, b = 9.624(1) ?, c = 29.390(2) ?, and β = 94.626(4)°. The modules are embedded in an extensively hydrogen bonded MA network. The assembly profile of MA and 4-BPO is unique and should be a harbinger for the design of novel functional assemblies. The 40-membered module mimics the self-assemblies of peptides and can be important in the design of “Haptens” from simple molecules. Index Abstract  Rod like crystals from water that are formed on mixing MA and 4-BPO are shown to consist of 4-molecule modules (MA–4-BPO–MA–4-BPO–) that contain a 40-membered ring, MA–BPO.