基于5-氯烟酸的锌（Ⅱ）和镉（Ⅱ）配合物的合成、晶体结构及荧光性质

通过水热方法,以5-氯烟酸（5-ClnicH）和2,2’-联咪唑（2,2’-biimidazole）分别与Zn（NO₃）₂·6H₂O和Cd（NO₃）₂·4H₂O反应,合成了2个配合物[Zn（5-Clnic）₂]_n（1）和[Cd（5-Clnic）₂（H₂biim）₂]（2）,并对其结构和荧光性质进行了研究。结构分析结果表明配合物1和2分别属于单斜晶系,C2c空间群和三斜晶系,P1空间群。配合物1具有二维层状结构,而且这些层通过Cl…Cl卤键作用进一步形成了三维超分子框架。2为单核镉配合物,通过分子间N-H…O、C-H…N和C-H…Cl氢键作用,单核的分子被进一步连接成了三维超分子结构。配合物1和2在室温下能分别发出很强的紫色和绿色荧光。     

基于配位键和次级作用力协同效应构建的两个Co (Ⅱ)/Cd (Ⅱ)配位超分子网络的结构及荧光性质

以3-羧基-1-（4-羧基苄基）吡啶溴酸盐（（H₂L） Br）分别与Co （Ⅱ）和Cd （Ⅱ）金属盐反应,制备了2个配合物[Co （L）₂（H₂O）₄]·2H₂O （1）和[Cd （L）2（H₂O）]·3H₂O （2）。晶体结构分析揭示配合物1是一个中性的单核配合物,其拥有丰富的并可作为超分子合成子的氢键和π-π作用力组分。对于1,单核的[Co （L）₂（H₂O）₄]实体首先通过氢键形成具有孔道结构的二维层,该二维层进一步通过π-π堆积作用形成三维的多孔配位超分子。配合物2具有一维的“之”字形链状结构,该链通过悬挂的L配体之间的π-π作用力形成一维梯形结构。该一维梯形链进一步通过梯形边之间存在的2种π-π堆积作用形成波浪状的二维层。二维层进一步通过8种类型的O—H…O氢键连接形成三维的超分子结构。根据拓扑的观点,配合物2中的一维链采取胶合板排列。此外,配合物2显示了强的紫外荧光发射,平均寿命为2.54 ns。     

3,5-二氨基苯甲酸构筑的Zn（Ⅱ）、Cd（Ⅱ）两种配合物的合成及晶体结构

利用3,5-二氨基苯甲酸配体合成了2种新的配合物[Cd（diaba）（phen）₂]NO₃·H₂O（1）和[Zn（diaba）（2,2’-bipy）₂]（2）（H₂diaba=3,5-diaminobenzoicacid;phen=1,10-phenanthroline,2,2’-bipy=2,2’-bipyridine）,并对其进行了元素分析、红外光谱和X射线单晶衍射测定。配合物1属于正交晶系,空间群为Fddd,a=1.42581（7）nm,b=2.56462（13）nm,c=3.09247（17）nm。配合物2属于单斜晶系,空间群为C2/c,a=1.27362nm,b=1.59278nm,c=1.51935nm,β=107.334°。配合物1和2都为单核晶体。配合物1的结构单元由1个Cd^Ⅱ、1个3,5-二氨基苯甲酸和2个phen构成。配合物2的结构单元由1个Zn^Ⅱ、1个3,5-二氨基苯甲酸和2个2,2’-bipy构成。两种配合物再通过氢键或π-π堆积形成三维超分子网络。研究了配合物的热稳定性和荧光性质。     

基于三唑配体的金属锰（Ⅱ）、锌（Ⅱ）配合物的合成、晶体结构与性质研究

在不同反应条件下,采用三唑衍生物作为配体与乙酸锰和硝酸锌反应,合成了2个具有三维结构的配位化合物{Mn（pytyba）（H₂O）₃]·2H₂O}_n（1）和{[Zn（pytyba）（H₂O）₃]·4H₂O}_n（2）,并通过元素分析、热重分析、荧光性、X射线单晶衍射对化合物进行分析。结构分析表明1和2有许多共同特征：两个聚合物的晶体均属于单斜晶系,C2/c空间群,Mn²⁺和Zn²⁺均为六配位畸变八面体配位结构,具有相似的热稳定性、荧光性以及相近的孔隙率。配体中的氧原子与金属离子配位形成一维链状结构,然后又通过O-H…N、O-H…O氢键作用和π…π芳香堆积形成超分子结构。此外,通过测定化合物抗氧化活性（SOD）的经典方法-Marklund法对配合物1和2的抗氧化活性进行了研究。     

基于二苯甲酰酒石酸构筑的钴（Ⅱ）、镍（Ⅱ）配合物的合成、结构、荧光及磁性质

在室温条件下合成了2个配合物[Ni（DBTA）（DMF）（H₂O）₄]（1）和[Co（DBTA）（DMF）（H₂O）₄]（2）（D-H₂DBTA=D-（+）-二苯甲酰酒石酸,DMF=N,N-二甲基甲酰胺）,并通过元素分析、FT-IR光谱、X射线单晶及粉末衍射表征了2个配合物的结构。X射线单晶衍射结果表明,2个配合物同构,属于单斜晶系,P2₁空间群。配合物由配位键形成零维结构,再通过分子间氢键形成三维网状结构。荧光分析表明当激发波长为280 nm时,配合物1和2具有较强的荧光。尽管2个配合物同构,但表现出不同的磁性质：配合物1主要表现出Ni²⁺离子间弱的反铁磁相互作用,而配合物2则表现为Co²⁺离子的磁各向异性以及Co²⁺离子间强的反铁磁相互作用。     

La（Ⅲ）、Nd（Ⅲ）与甜菜碱类衍生物形成的包含（H2O）6分子簇的配合物的晶体结构

利用配体1,5-二（3-羧基吡啶基）-N-甲基二乙胺（L）合成2种稀土金属配合物{[La₂L₄（H₂O）₂]（ClO₄）₆·6H₂O}_n（1）和[Nd₂L₄（DMF）₆（H₂O）₂]₂（ClO₄）₆·4H₂O（2）。用红外光谱和X-射线单晶衍射表征配合物的晶体结构。结构分析表明：配合物1属于三斜晶系,P1空间群,其晶胞参数为a=1.4966（3）nm,b=1.5597（4）nm,c=1.9568（4）nm,α=86.776（6）°,β=77.723（7）°,γ=87.168（7）°,Z=2。在配合物1中,一对La（Ⅲ）原子被2个羧基桥联,形成双核结构;双核结构进一步被羧基连接,从而形成平行于c轴的一维链。值得注意的是配合物1的晶体结构中包含着由氢键连接的6个H₂O分子组成的水分子簇。配合物2属于三斜晶系,P1空间群,晶胞参数为a=1.0408（4）nm,b=1.3541（5）nm,c=2.975（1）nm,α=94.390（8）°,β=91.720（7）°,γ=95.230（4）°,Z=2。配合物2中4个羧基连接一对Nd（Ⅲ）原子,形成四轮状结构,其中2个羧基采取syn-syn双原子桥联模式,而其余2个羧基则采取单原子桥联模式。     

两个3-氧乙酸基苯丙烯酸构筑的Cd（Ⅱ）配合物的合成、晶体结构和荧光性质

用水热法合成得到2个Cd（Ⅱ）配合物,[Cd（L）（4,4’-bipy）_0.5（H₂O）₂]_n（1）和[Cd（L）（bpp）（H₂O）]_n·2nH₂O（2）（L=3-氧乙酸基苯丙烯酸,4,4’-bipy=4,4’-联吡啶,bpp=1,3-二吡啶基丙烷）,并测定了他们的晶体结构。结构分析表明,在配合物1中,L配体连接Cd（Ⅱ）中心形成一维[CdL]_n链,4,4’-联吡啶配体进一步桥联形成二维层状结构;配合物2是一个二重穿插的二维层状结构。此外,对配合物的荧光性能测试表明,它们在绿光区域有荧光发射。     

基于双吡啶脲类Cd(Ⅱ)、Zn(Ⅱ)、Hg(Ⅱ)配合物的合成及晶体结构

间苯二胺和3-吡啶异氰酸酯在甲苯中加热回流得到双吡啶脲类配体L,然后将配体分别与CdSO₄·8H₂O,ZnI₂,HgI₂,HgCl₂进行配位反应,得到4个配合物{[Cd（L）（SO₄）（H₂O）₃]·H₂O}_n（1）,{[Zn（L）I₂]·2C₂H₅OH}_n（2）,{[Hg（L）I₂]·C₂H₅OH}_n（3）,[Hg（L）Cl₂]·H₂O（4）,并用元素分析、FT-IR、X射线单晶衍射、粉末衍射对其进行了表征。配合物1形成一维螺旋链结构,配合物2和3形成一维“之”字链结构,配合物4形成32元环状结构。     

基于柔性双吡啶双酰胺和两种不同多羧酸配体的三个Cu（Ⅱ）/Co（Ⅱ）配位聚合物：组装、结构和性质

通过水热合成得到3个有机金属配位聚合物,即[Cu（1,2-BDC）（L）]（1）,[Cu（HBTC）（L）]·2H₂O（2）,[Co（HBTC）（L）]·H₂O（3）,（L=N,N-双（3-氨基吡啶）乙二酰胺,1,2-H₂BDC=1,2-邻苯二甲酸和H₃BTC=1,3,5-均苯三甲酸）。配合物1是基于1D[Cu-1,2-BDC]_n和[Cu-L]_n链形成的一个3DCdSO₄-型拓扑结构。配合物2~3是同构的,均显示出2D双层（3,5）-连接的{4²·6⁷·8}{4²·6}拓扑结构。相邻的2D双层网络通过分子间的氢键（配合物2）和π-π堆积（配合物3）作用进一步拓展成3D超分子框架。我们对芳香羧酸和中心金属离子对配合物结构的影响进行了详细的讨论。此外,还研究了配合物1~3的电化学性质和固态荧光性质。     

由联苯三羧酸和含氮配体构筑的钴(Ⅱ)、铅(Ⅱ)和锌(Ⅱ)配合物的合成、晶体结构及荧光性质

采用水热方法，用联苯三羧酸配体（H₃btc）和菲咯啉（phen）或2，2''-联吡啶（2，2''-bipy）分别与CoCl₂·6H₂O、PbCl₂和ZnCl₂反应，合成了一个单核配合物[Co（Hbtc）（phen）₂（H₂O）]·3H₂O（1）以及2个一维链状配位聚合物[Pb（μ₃-Hbtc）（2，2''-bipy）]_n（2）和{[Zn₃（μ₂-btc）₂（μ₂-H₂O）（2，2''-bipy）₃（H₂O）₅]·8H₂O}_n（3），并对其结构和荧光性质进行了研究。结构分析结果表明3个配合物分别属于正交和三斜晶系，Pna2₁和P1空间群。配合物1具有零维单核结构，而且这些单核钴单元通过O-H…O氢键作用进一步形成了三维超分子框架。而配合物2和3具有基于双核单元的一维链结构。研究表明，配合物2和3在室温下能发出蓝色荧光。     

Ab-initio study of electronic,optical, thermal,and transport properties of Cr4AlB6

Theoretical investigation of different physical parameters of Cr₄AlB₆ have been done within the framework of density functional theory. Cr₄AlB₆ is a no band gap material. Its Cr-3d states contributes the most at the Fermi level. Thermal properties are investigated using quasi-harmonic Debye model as implemented in Gibbs code for different values of pressure and temperature. Study of transport property suggests that its electrical conductivity increases nonlinearly with increase in temperature but the relative change in its value is very low whereas its thermal conductivity increases linearly with the increase in temperature and relative increase in thermal conductivity is very high. The behavior of Cr₄AlB₆ is anisotropic and property is ceramic. It has potential applications in making ceramic capacitors. Its reflectivity is high in low energy region. It suggests that material can be used as coating material for far-infrared radiation. Study of the transport property suggests that because of very high value of thermal conductivity, it can be used for heat sink applications.     

Thermal,structural and electrical properties

The chloro compound of 3-hydroxy-2-quinoxalinecarboxylic acid with nickel(II) has been prepared in ethanolic solution from which a solid compound was isolated. Spectral and magnetic measurements show that the nickel ions are in an octahedral environment. Thermogravimetry, differential thermal analysis and electrical conductivity data are reported for 3-hydroxy-2-quinoxalinecarboxylic acid and its nickel complex. The conductivity measurements indicate that electron/hole traps are emptied during heating of the complex but repopulation occurs in about 24 h at room temperature.     

Reliability of flexible electrically conductive adhesives

Based on our previous work about electrically conductive adhesives (ECAs), a flexibilizer named 1,3‐propanediol bis (4‐aminobenzoate) was used to fabricate flexible ECAs (FECAs). ECAs, FECAs, and electronic devices connected by them were carried out the hot and humid aging test under constant humidity level of 85% relative humidity at 85 °C for 600 h. After aging, the bulk resistance change of ECAs was about 26%, that of FECAs was a little higher, about 29%. The contact resistance change of devices connected by ECAs and FECAs was very great, about 450% and 410%, respectively. The bonding area at connection interface between colloids and devices had delamination, even cracks. The delamination of ECAs was calculated about 60%, the average shear strength of ECAs was reduced about 45%, and those of FECAs were about 50% and 30%, respectively, so FECAs had a higher bonding stability in hot and humid environment. Copyright © 2012 John Wiley & Sons, Ltd.     

Assimilation of manganese metal ion doped hydroxyapatite by Co-Precipitation technique

Calcium phosphate mineral [HAp] is a vital ingredient in orthopaedics, dental and hard tissue applications in mammals. Since it can absorb a large number of impurities, the doped HAp has the potential for biomedical applications using its physical and structural properties. In this research, the Mn-doped HAp in which x calcium atoms are replaced by Mn (Ca_10-x Mn_x (PO₄)₆(OH)₂ where x = 0.2, 0.4, 0.6, 0.8 mol) is obtained by the co-precipitation method. The physical properties of Mn-doped HAp, such as average crystallite size and degree of crystalline, are determined through XRD studies. The peaks corresponding to the functional groups PO4^3?, CO, and OH of the samples are identified by FTIR studies. The impedance spectroscopy method helps in the investigation of electrical conductivity, and dielectric loss in the impedance spectra for various doping concentrations. The average molar ratio of HApMn is determined with the help of EDX. It was found that there is a decrease in the degrees of crystallization with the doping element concentration (Mn) in all the samples. The diffraction (hkl) indices are confirmed from the selected area electron diffraction (SAED) rings, and the morphological study of the samples using TEM confirms the shape as a rod-like structure. To conclude, the variation in the characteristics of HAp relies on the doping concentration of Mn.     

Typical superparamagnetism with improved electrical properties of nano modified bismuth ferrite multiferroic composites

Multiferroic composites with the chemical formula, (0.5) BiFeO₃ + (0.5) Ni_0.5Zn_0.5Fe₂O₄, in bulk and nano forms were synthesized by preparing bismuth ferrite (BiFeO₃ or BFO) in bulk (B) and nano (N) forms and nickel zinc ferrite (Ni_0.5Zn_0.5Fe₂O₄or NZFO) in nano form. Single phase BFO was synthesized using conventional solid-state reaction as well as sol-gel autocombustion methods and NZFO powders were prepared by using sol-gel autocombustion method, respectively. X-ray diffraction (XRD) studies reveal the existence of rhombohedrally distorted perovskite structure for BFO and cubic spinel phase for NZFO in single phase as well as composite samples. Microstructural studies and energy dispersive spectroscopy (EDS) data reveal the formation of grains, intergranular porosities and chemical purity of the synthesized samples. Dielectric and AC conductivity measurements confirm the existence of space charge polarization along with the small polaron model in these composites. Ferroelectric and magnetic studies show that there was a considerable enhancement in the ferroelectric and magnetic orders for the nano form of the BFO (N) + NZFO composite. The observed remnant polarization values 2.80388 & 7.75901 μC/cm², saturation magnetization values 37.96072 & 40.47491emu/gm for bulk BFO (B) + NZFO and nano BFO (N) + NZFO composites, respectively. Interestingly, both the samples exhibit superparamagnetic behaviour at room temperature with coercivities close to zero. This typical behaviour is attributed to the corresponding anisotropic contributions originated from the individual constituents. The observed variations in BFO (N) + NZFO sample attributed to the corresponding structural modifications brought about by the variations due to its size effect in the present work.     

Tetrametallic macrocyclic frameworks constructed from ferrocenedicarboxylato and 2,2-bipyridine: synthesis, molecular structures and characteristics

Four novel tetranuclear macrocyclic compounds [Cd₂(η²-O₂CFcCO₂)₂(2,2^′-bpy)₂(H₂O)₂] · 2H₂O (1), [Zn₂(η²-O₂CFcCO₂)₂(2,2^′-bpy)₂(H₂O)₂] · CH₃OH · H₂O (2), [Co₂(O₂CFcCO₂)₂(2,2^′-bpy)₂(μ₂-OH₂)₂] · CH₃OH · 2H₂O (3), and [Ni₂(O₂CFcCO₂)₂(2,2^′-bpy)₂(μ₂-OH₂)₂] · CH₃OH · 2H₂O (Fc=(η⁵-C₅H₄)Fe(η⁵-C₅H₄) (4) have been synthesized and structurally characterized by single crystal diffraction. The magnetic behaviors for compounds (3) and (4) are studied in the temperature range of 5.0-300 K. The results show that the antiferromagnetic coupling of Co^II-Co^II pairs occurs in (3), and unusual global ferromagnetic coupling between nickel (II) ions exists in (4). The solution-state differential pulse voltammetries of compounds (1)-(4) all show two peaks with large separations (ΔE) that indicate strong interactions between two ferrocene moieties. Their fluorescent and thermal properties were also investigated.     

Insight into the electronic,optical, thermodynamic,and thermoelectric properties of novel chalcogenides: An ab initio study

Ternary chalcogenides with direct band gaps are remarkable for being used in many optoelectronic applications. We investigated for structural, electronic, optical, and transport characteristics of new Ba₂CdCh₃ (Ch = S, Se, Te) semiconductors using the full-potential linearized augmented plane wave (FP-LAPW) approach. The band structures of these compounds confirm a direct type of band gap. The phonon dispersion plots along with the predicted negative formation energies suggest these compounds to be thermodynamically stable. Additionally, important optical characteristics were computed and thoroughly explained. The different ELF spectra were calculated in which strong peak correlate precisely with plasma resonance. Moreover, we also explored the thermodynamic characteristics of the ternary systems by employing the quasi-harmonic Debye model. These compounds were also suitable for thermoelectric applications based on the detailed discussion of the computed significant thermoelectric properties. In general, the advancement of various and promising semiconducting devices and their applications will be supported by the present study.     

Structural,mechanical, electronic,and thermodynamic properties of pure tungsten metal under different pressures: A first-principles study

The structural, mechanical, electronic, and thermodynamic properties of pure W metal under different pressures have been investigated using the first-principles method. Our calculated structural parameters are in good agreement with experimental and previous theoretical results. The obtained elastic constants show that pure W metal is mechanically stable. Elastic properties such as the bulk modulus (B), shear modulus (G), Young's modulus (E), Poisson's ratio (ν), Cauchy pressure (C′), and anisotropy coefficients (A) are calculated by the Voigt-Reuss-Hill method. The results show that the pressure can improve the strength of pure tungsten and has little effect on the ductility. In addition, the total density of states as a function of pressure is analyzed. Thermodynamic properties such as the Debye temperature, phonon dispersion spectrum, free energy, entropy, enthalpy, and heat capacity are also discussed.     

Mechanical and Morphological Properties of Bio-Phenolic/Epoxy Polymer Blends

Polymer blends is a well-established and suitable method to produced new polymeric materials as compared to synthesis of a new polymer. The combination of two different types of polymers will produce a new and unique material, which has the attribute of both polymers. The aim of this work is to analyze mechanical and morphological properties of bio-phenolic/epoxy polymer blends to find the best formulation for future study. Bio-phenolic/epoxy polymer blends were fabricated using the hand lay-up method at different loading of bio-phenolic (5 wt%, 10 wt%, 15 wt%, 20 wt%, and 25 wt%) in the epoxy matrix whereas neat bio-phenolic and epoxy samples were also fabricated for comparison. Results indicated that mechanical properties were improved for bio-phenolic/epoxy polymer blends compared to neat epoxy and phenolic. In addition, there is no sign of phase separation in polymer blends. The highest tensile, flexural, and impact strength was shown by P-20(biophenolic-20 wt% and Epoxy-80 wt%) whereas P-25 (biophenolic-25 wt% and Epoxy-75 wt%) has the highest tensile and flexural modulus. Based on the finding, it is concluded that P-20 shows better overall mechanical properties among the polymer blends. Based on this finding, the bio-phenolic/epoxy blend with 20 wt% will be used for further study on flax-reinforced bio-phenolic/epoxy polymer blends.