铜L-色氨酸配合物的合成与表征

利用液相反应合成法制得了铜(Ⅱ)和L-色氨酸的配合物,结合元素分析、差示扫描量热与热重分析联用、粉末X射线衍射法以及红外光谱实验手段对该配合物进行表征。结果表明,1个铜离子能够与2个L-色氨酸分子通过侧链氨基上的氮原子和羧基上的氧原子配合,形成稳定的配合物。利用太赫兹时域光谱法获得了室温条件下铜-L-色氨酸配合物在低频波段的光谱特征,并结合密度泛函理论计算对太赫兹光谱进行分析。该配合物在太赫兹波段的吸收对应于分子整体的振动,涉及吲哚环和侧链的扭曲振动。研究结果有助于深入了解铜离子与氨基酸的相互作用,以及铜离子在复杂生物体中所起的作用。     

卤离子桥联铜(Ⅱ)配合物的结构相变与热致磁性变化

以质子化2-丙胺为阳离子合成了铜(Ⅱ)配合物[(CH3)2CHNH3]CuBr3-xClx(x＝0~3), 该系列配合物是卤离子桥联的一维链状结构. 磁性研究表明, 配合物为反铁磁相互作用, 其χmT在高温时出现突跃, 对应于结构相变. Cu(Ⅱ)配离子在高温呈拉长八面体结构, 在低温呈四方锥结构, 伴随着桥连方式的改变, 配合物从低温相的反铁磁性变为高温相的铁磁性. 根据晶体场理论分析, 由于配位X-的不同导致晶体场分裂能发生变化, 相转变温度伴随着氯离子所占比例不同呈现规律性变化. 通过配合物[(CH3)2CHNH3]CuX3(X-=Br-或Cl-)的磁性比较提出了[(CH3)2CHNH3]CuBr3-xClx(x=1, 2)的可能结构, 并使用铁磁均匀一维链模型对高温相配合物磁性进行了拟合.     

多核过渡金属配合物的磁性研究

本文以双核Cu(II)配合物作为磁性研究的典型例子,扼要地介绍了磁性离子的基本性质,多原子桥联多核配合物的变温磁化率、超交換相互作用及其机理的理论模型,并对近年来多核配合物的磁性研究的某些进展作了简要评述。     

1,1-环丁烷二羧酸单、双核铜配合物的合成、晶体结构、热分析和磁性

Two new copper complexes, [Cu（cbdc）（phen）（H2O）]·2H2O （1） and [Cu2（cbdc）（phen）2（H2O）2]（ClO4）2·H2O （2） （cbdc= 1,1-cyclobutanedicarboxylate and phen= 1,10-phenanthroline）, were synthesized by reaction of cbdc with Cu（ClO4）2 and phen in ethanol aqueous solution. Complex 1 crystallizes in monoclinic system with space group P2（1）/c and a=0.9428（4） nm, b= 1.2183（5） nm, c= 1.6265（7） nm, β= 102.418（5）°, V= 1.8246（13） nm^3, Z=4, R=0.0445, wR2=0.0947. The structure of 1 is discretely mononuclear, which is packed by π…π interaction forming a 3D supramolecular structure where Cu（Ⅱ） ion is five-coordinated and has square-pyramidal coordination geometry. Its thermal decomposition procedure detail was studied by thermal analysis TG-DSC. Complex 2 belongs to monoclinic system with space group P2（1）/c and a=0.8897（3） nm, b= 1.9130（8） nm, c= 1.9936（8） nm,β=99.04（2）°, V=3.351（2） nm^3, Z=4, R=0.0540, wR2=0.1102. The structure of 2 is a discrete binucleus, where Cu（1） is four-coordinated by phen and cbdc in a square-planar geometry while Cu（2） is five-coordinated by phen, one O of cbdc and two H2O, which can be best described as distorted trigonal-bipyramidal geometry. Cu（1） and Cu（2） are linked by carboxylic group of cbdc in a bidentate bridging fashion. Variable-temperatttre magnetic susceptibilities of 2 in 2-300 K showed that its magnetic behavior obeyed Curie law.     

磁性聚合物微球的制备及其热重曲线的特征分析

采用改进的种子乳液聚合法制得了微米尺度表面羧基功能化的超顺磁性复合微球.通过动态光散射粒度仪(DLS)、透射电子显微镜(TEM)、振动样品磁强计(VSM)对所制备的磁性功能聚合物微球的各项性能进行了表征.通过热失重分析(TGA)、热质联用分析(TGA-MS)、拉曼光谱(RS)、X射线光电子能谱(XPS)对磁性功能聚合物...     

TATP-铜(II)-L-丝氨酸(L-精氨酸)配合物与DNA的相互作用

采用电子吸收光谱、荧光光谱、粘度测定和琼脂糖凝胶电泳方法研究了配合物[Cu(TATP)(L-Ser)(H2O)]·ClO4(1)和[Cu(TATP)(L-Arg)(H2O)]2ClO4·0.5H2O(2)(TATP=1,4,8,9-四氮三联苯, L-Ser=L-丝氨酸, L-Arg=L-精氨酸)与DNA之间的相互作用. 结果表明, 配合物电子吸收光谱的最大吸收峰在加入DNA后产生明显的减色效应, 配合物能极大地淬灭溴化乙啶(EB)-DNA体系的荧光, DNA的粘度随配合物浓度的增加而增大, 表明配合物对DNA有较强的插入作用, 作用力大小为配合物2>1; 另外, 凝胶电泳实验结果表明配合物在维生素C存在的条件下对pBR322 DNA具有显著的断裂作用.     

L-丙氨酸和L-组氨酸与铜离子混配合物的热化学

合成了一种新的氨基酸与铜 (Ⅱ )混配型配合物 ,并用具有恒定温度环境反应热量计 ,测定了配合物和反应物在 2 98 2K时 2mol·L-1HCl溶液中的溶解焓 ,由设计的热化学循环得出了配合反应焓变ΔrHm =1 45 92kJ·mol-1,根据热力学原理计算出该配合物的标准摩尔生成焓ΔfHm ,[Cu(Ala·His) ]·4H2 O =-2 0 0 6 5 8kJ·mol-1,为进一步研究这类物质提供了热化学基础参数。     

L-α-氨基酸铜(Ⅱ)-联吡啶混配配合物的合成及表征

合成了 4种氨基酸 铜 (Ⅱ ) 2 ,2′ 联二吡啶 (Bpy)的混配配合物 ,用元素分析、摩尔电导率、IR和UV -Vis对配合物进行了表征和结构推测。 4种混配配合物的组成分别为 :[Cu(Bpy) (L thre) ]·ClO4·H2 O ,[Cu(Bpy) (L ile) ]·ClO4·0 .5H2 O ,[Cu(Bpy) (L meth) ]·ClO4·0 .5H2 O ,[Cu(Bpy) (L ly) ]·ClO4·H2 O(L thre为苏氨酸 ,L ile为异亮氨酸 ,L meth为蛋氨酸 ,L ly为赖氨酸 )。Bpy和L 氨基酸皆作为双齿配体与中心铜离子发生配位。     

2-苯甲酰苯甲酸铜配合物的合成、电化学、荧光及磁性研究

以2-苯甲酰苯甲酸(HL)和1,10-邻菲啰啉(Phen)为配体合成了一个新的铜(Ⅱ)配合物{[Cu2(Phen)4(NO3)][Cu(Phen)2(L)]2(L)2(NO3)3}·2H2O(1)。该化合物晶体属三斜晶系,空间群P1,晶胞参数:a=1.138 57(5)nm,b=1.193 49(7)nm,c=2.615 31(13)nm,α=89.428 0(10)°,β=82.753(2)°,γ=74.537 0(10)°,V=3.3968(3)nm3,Dc=1.408 g·cm-3,Z=1,μ(Mo Kα)=0.700 mm-1,F(000)=1 480,最终偏离因子R1=0.057 1,wR2=0.133 4。在标题配合物分子中,有2个单核阳离子[Cu(Phen)2(L)]+和1个双核阳离子[Cu2(Phen)4(NO3)]3+,中心铜(Ⅱ)离子的配位数都是五。测定了标题配合物的电化学、荧光和磁性。结果表明:在循环伏安过程中,配合物的电子转移是准可逆的,对应的电极反应是Cu(Ⅱ)/Cu(Ⅰ);当激发波长为488 nm时,配合物在494 nm附近有较强的荧光发射峰;在300～52 K,配合物具有抗磁性。     

2-苯甲酰苯甲酸铜配合物的合成、电化学、荧光及磁性研究

以2-苯甲酰苯甲酸(HL)和1,10-邻菲啰啉(Phen)为配体合成了一个新的铜(Ⅱ)配合物{[Cu₂(Phen)₄(NO₃)][Cu(Phen)₂(L)]₂(L)₂(NO₃)₃}·2H₂O (1)。该化合物晶体属三斜晶系,空间群P1,晶胞参数:a=1.138 57(5) nm,b=1.193 49(7) nm,c=2.615 31(13) nm,α=89.428 0(10)°,β=82.753(2)°,γ=74.537 0(10)°,V=3.3968(3) nm³,D_c=1.408 g·cm^-3,Z=1,μ(MoKα)=0.700 mm^-1,F(000)=1 480,最终偏离因子R₁=0.057 1,wR₂=0.133 4。在标题配合物分子中,有2个单核阳离子[Cu(Phen)₂(L)]⁺和1个双核阳离子[Cu₂(Phen)₄(NO₃)]³⁺,中心铜(Ⅱ)离子的配位数都是五。测定了标题配合物的电化学、荧光和磁性。结果表明:在循环伏安过程中,配合物的电子转移是准可逆的,对应的电极反应是Cu(Ⅱ)/Cu?髣;当激发波长为488 nm时,配合物在494 nm附近有较强的荧光发射峰;在300~52 K,配合物具有抗磁性。     

Synthesis,characterization, thermal,electrical and magnetic properties of polyaniline composites with rare earth gadolinium coordination complex

Novel polyaniline/gadolinium (PANI/Gd) composites were successfully synthesized by “in‐situ” polymerization at the presence of rare earth Gd coordination complex and D‐tartaric acid (an a dopant). It is rarely to find the studies on related field to add rare earth Gd coordination complex as fillers. Fourier transform infrared (FTIR) spectra, X‐ray diffraction (XRD) and scanning electron microscope (SEM) were used to examine the structure and surface appearance characterization of materials. The thermal stability performance of composites was investigated by thermogravimetry and derivative thermogravimetry (TG‐DTG). Electrochemical performance was measured by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge–discharge test. The magnetic property was investigated by physical property measurement system (PPMS). The structure and surface appearance characterization and the magnetic properties jointly demonstrate the polymerization of rare earth Gd coordination complex and PANI–D‐tartrate (DTA) not only simple physical mixing but also chemical mixing. TG‐DTG analysis suggests that thermal stability of PANI/Gd composites is higher than that of PANI–DTA. Electrochemical performance tests and SEM indicate that the composite (PANI/Gd = 3.3:1,mass ratio) has the most regular morphology and best specific capacitance. The magnetization of the composite (PANI/Gd = 3.3:1,mass ratio)is evidently smaller compared with PANI–DTA and rare earth Gd coordination complex. Copyright © 2016 John Wiley & Sons, Ltd.     

Enhancing the electro-optical properties of ferroelectric liquid crystals by doping ferroelectric nanoparticles

The effects on the physical and electro-optical properties of ferroelectric liquid crystals (FLCs) after the doping of a dilute suspension of ferroelectric nanoparticles (BaTiO₃) have been studied. Due to the permanent electric dipole moments of the ferroelectric nanoparticles, the spontaneous polarisation of FLCs with low doping concentration was about twice that of pure FLCs, in addition to a significant improvement in the dielectric properties, the response time and the V-shaped switching in the chiral smectic C (SmC?) phase. The results obtained point the way to an alternative for improving the applicability of FLCs without resorting to chemical synthesis.     

Preparation and Performance of Dual-functional Magnetic Phase-change Microcapsules

The fabrication of desired anti-magnetic materials for irradiation shielding remains a challenge to date. In this work, a new type of dual-functional magnetic shielding phase change microcapsules with paraffin as the core, melamine-formaldehyde (MF) resin as the shell and doped with magnetic particles in the shell were successfully prepared by in situ polymerization. The magnetic particles were dispersed in the shell layer by coating a hydrophilic emulsifier on the surface. These microcapsules were specifically applied to the field of magnetic shielding by the screen printing method. The effect of magnetic particles on the performance of phase-change microcapsules was examined by differential scanning calorimetry and thermogravimetric analyses. The magnetic type and magnetic strength of the microcapsules were studied by the vibrating sample magnetometer. Moreover, the effects of different magnetic particles (Fe₃O₄, CrO₂) on the performance of phase change microcapsules and the magnetic strength of microcapsules were compared. The results showed that these two kinds of magnetic particles can greatly improve the phase change latent heat, thermal stability, and thermal conductivity of the microcapsules. Finally, the great magnetic shielding role of these microcapsules was demonstrated in both static and pulsed magnetic fields through the screen printing of magnetic shielding ink on wallpaper. Incorporating 0.5 g Fe₃O₄ inside of microcapsules, specifically, the magnetic intensity was effectively reduced by ∼250 Oe within a short distance in the static field. We expect that these magnetic microcapsules hold great potential for the shielding of irradiations via the screen printing on various substrates.     

Structure and thermal properties of bamboo viscose,Tencel and conventional viscose fiber

Comparative investigations of new regenerated cellulosic fibers, bamboo viscose fiber and Tencel, together with conventional viscose fibers have been carried out to explain the similarity and difference in their molecular and fine structure. The analyses jointly using SEM, XRD and IR reveal that all the three fibers belong to cellulose II. Tencel consists of longer molecules and has a greater degree of crystallinity, while bamboo viscose fiber has a lower degree of crystallinty. TG-DTG-DSC study shows three fibers resemble in thermal behavior with a two-step decomposition mode. The first step is associated to water desorption, suggesting that bamboo viscose fiber holds better water retention and release ability, the second a depolymerization and decomposition of regenerated cellulose, indicating that Tencel is more thermally stable in this process than bamboo and conventional viscose fiber.     

Multifunctional polythreading coordination polymers: spontaneous resolution, nonlinear-optic, and ferroelectric properties

The reactions of methylenediisophthalic acid (H₄L) and N‐auxiliary ligands (1,2‐bis(4‐pyridyl)ethylene, 1,2‐bis(4‐pyridyl)ethane) with transition‐metal centers (Co²⁺/Mn²⁺) have given rise to four unprecedented polythreading coordination polymers. Single‐crystal X‐ray diffraction analyses revealed that the compounds can be described as 3D^2??2[1D²⁺]+2D^6? for 1 , 3D^4??1D²⁺+1D^6? for 2 , and 2D^4??0D²⁺+2[1D^3?] for 3 and 4 . All the polymers are formed through the assembly of two kinds of motifs with opposite charges. Noncentrosymmetric structures and multifunctionality in 2 – 4 are established by varying ligands and metal centers. Spontaneous resolution upon crystallization occurred in compounds 3 and 4 in the absence of any chiral source. The enantiomers of 3 and 4 consist of three chiral building blocks of L^4?/HL^3? and Mn²⁺ centers. In the solid state, polar compounds 2 – 4 exhibit nonlinear‐optic (NLO) and ferroelectric properties at room temperature. The assembly of two kinds of motifs with opposite charges provides a useful method for the preparation of multifunctional compounds.     

Dependence of dielectric,ferroelectric, and piezoelectric properties on crystalline properties of p(VDF‐co‐TrFE) copolymers

Thermal processing at various temperatures has been used to fabricate poly(vinylidene fluoride‐co‐trifluoroethylene) [P(VDF‐co‐TrFE)] films with varied crystalline properties in an attempt to improve their piezoelectric properties. Although the dielectric constant of the films annealed at higher temperature is smaller than that of cooled and quenched ones, it has been shown that the annealed films possess larger crystallinity and stacked lamellar crystal grain size. The ferroelectric domains deriving from crystal region in all the samples are effectively improved by hot polarization. As a result, the remnant polarizations (P_r) and coercive electric field (E_c) of the corresponding films are improved at a low frequency due to the response of dipoles in crystal phase, and the largest piezoelectric constant in the longitudinal thickness mode (d₃₃=?25 pC/N) is obtained in an annealed copolymer film. The results illustrate improving the crystal structure of P(VDF‐co‐TrFE) is an effective way to realize high electromechanical properties, which provides broadly applied scenery for this kind of copolymer in piezoelectric components. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Polymerization,structure and thermal properties of ODPA-DMB polyimide films

A new high molecular weight polyimide based on 4,4-oxidiphthalic anhydride (ODPA) dianhydride and 2,2-dimethyl-4,4-diaminobiphenyl (DMB) diamine has been synthesizedvia a one-step polymerization method. This polyimide is soluble in phenolic solvents. Films from 7 to 30 m thick were cast from the polymer solution and show in-plane orientation on a molecular scale detected by Fourier transform infrared spectroscopy experiments. This anisotropic structure leads to anisotropic optical properties arising from two different refractive indices along the inplane and out-of-plane directions. ODPA DMB possesses high thermal and thermo-oxidative stability. The glass transition temperature has been determined to be 298 °C. Dynamic mechanical analyses show two relaxation processes appearing above room temperature: the - and the -relaxation processes. The -relaxation corresponds to the glass transition while the -relaxation is a secondary relaxation process associated with the non-cooperative subsegmental motion.Dedicated to Professor Bernhard Wunderlich on the occasion of his 65th birthdayYHK acknowledges the support from the Yonam Foundation, Korea. This work was also supported by the Center of Molecular and Microstructure of Composites (CMMC) of NSF/EPIC/Industry, SZDC gratefully acknowledges the support from his PYI Award (DMR-9157738) from the National Science Foundation.     

Effects of metal salts on the thermal decomposition of edta-gel precursors for ferroelectric ceramic powders

Raw chemicals such as metal nitrates and chlorides were found to affect the thermal decomposition behaviour of EDTA-gel precursors used for the production of ceramic powders. Fine, homogeneous ceramic powders were produced from nitrate solutions while chlorides gave segregated phases. In studies on the production of lead zirconate titanate (PZT) using chlorides, the segregation and loss of lead was observed and shown to be caused by the formation and evaporation of PbCl₂. Thermal analysis (DTA/TG) quantitatively proved the suggested reaction mechanism for this phase segregation. Crystallization of the desired perovskite phase of lead zirconate titanate (PZT) and barium titanate (BT) initiated at temperatures as low as 250°C in the nitrate-EDTA precursors. Water of crystallization and formation of BaCO₃ in the barium titanate precursor were suggested to account for differences in the observed decompositional behaviours of the BT and PZT precursors.     

Transition metal coordination complexes based on V-shaped bis-triazole ligand: syntheses,structures, and properties

Hydrothermal reactions of 1,3-bis(1,2,4-triazol-1-yl)benzene (btb) and M(NO₃)₂ (M = Co²⁺ (1), Cu²⁺ (2)) afforded two new coordination polymers, [Co(btb)₂(NO₃)(H₂O)]_n·NO₃·H₂O (1) and [Cu(btb)₂(NO₃)₂]_n (2), respectively. Single-crystal X-ray diffraction reveals that 1 crystallizes in the space group P2₁/m and 2 crystallizes in the space group Pī, both showing a double-stranded chain structure. The 1-D chains are interconnected via π?π interactions to lead to 2-D ladder-like supramolecular architectures. In addition, magnetic behavior and thermal stability of 1 and 2 have been investigated. For 1, weak antiferromagnetic interactions are observed at low temperature, and the data obey the Curie–Weiss law χ_M = C/(T?θ), with C = 3.22 cm³·mol^?1·K and θ = ?10.39 K. For 2, the decrease of the χT vs. T curve at low temperature is the result of intermolecular antiferromagnetic magnetic interactions.