Preparation and characterization of a novel strong-fluorescent hydrotalcite-like compound (Al-HTLc)

A novel strong-fluorescent hydrotalcite-like compound (Al-HTLc) was synthesized by coprecipitation. In the sample, the content of aluminum(III) in the layers was decreased to a proper value. The Al3 ions coordinated with 8-hydroxyquinolines (8-HQ) which were dispersed into the anions in the interlayer region. The sample was characterized by XRD, XPS, FT-IR, TG-DSC, UV-Vis, and fluorescence spec- troscopy; its composition and structure were also determined. The results indicate that the sample can emit fluorescence (487 nm) with a strong fluorescence intensity (4.9×105 (a.u.)). The fluorescent lifetime and fluorescence quantum yield of Al-HTLc were measured to be 21.24 ns and 67%, respectively, higher than those of pure 8-hydroxyquinoline aluminum (Alq3). The result of TG-DSC measurement clearly shows the enhanced thermal stability of Al-HTLc compared with that of MgAl-LDH and pure Alq3. Al-HTLc may be used as a novel luminescent functional material.     

Synthesis and characterization of a Eu-containing polymer precursor featuring thenoyltrifluoroacetone and 5-acrylamido-1,10-phenanthroline

A polymerizable ligand, 5-acrylamido-1,10-phenanthroline (L), was synthesized. Its Eu(III) complex with 2-thenoyltrifluoroacetone (HTTA) was prepared and characterized by elemental analysis, IR, MS, and ¹H NMR spectra. The photophysical properties of the complex were studied in detail by using UV, luminescence spectra, luminescence lifetime and quantum yield. The complex shows a remarkable luminescence quantum yield at room temperature (40.1%) upon ligand excitation and a long ⁵D₀ lifetime (590 μs), which makes it not only a promising light-conversion molecular device but also an excellent luminescent polymer precursor.     

单核稀土Gd配合物的合成及表征

采用溶剂热法构筑一例单核稀土Gd配合物(1),采用X射线单晶衍射、元素分析、X射线粉末衍射及热重分析对其进行了结构解析和基本表征.配合物1属于三斜晶系,空间群是P-1,单胞参数为a=0.807 84(5)nm,b=1.410 47(16)nm,c=1.545 81(15)nm,α=82.007(8)°,β=78.940(7)°,γ=75.911(7)°.结构解析表明,配合物1中的中心离子Gd~(3+)与配体的羧基O原子和配位的DMF分子的O原子结合形成八配位的畸变四方反棱柱体,分子间通过配体桥联,形成三维框架结构.     

钴铬水滑石的合成及表征

采用共沉淀法合成了一系列不同Co/Cr物质的量比的碳酸根型水滑石。用X－衍射、红外光谱、差热、热重、分光光度等方法对其组成和结构进行了研究。结果表明Co/Cr投料比为2到3时能形成结晶度好、纯度高的水滑石。初步推测了部分产物的组成及所含水滑石的化学式。     

电化学聚合漆酚-钆螯合物的合成与表征

利用电化学方法及渗透扩散方法合成了电化学聚合漆酚-钆螯合物(EPU—Gd^3 )，采用X光电子能谱、红外光谱、ESR、荧光、动态机械热分析(DMTA)和元素分析法表征螯合物膜，分析了螯合物可能存在的结构．元素分析表明，Gd^3 含量达11．99％．由于存在Gd^3 与EPU的配位作用，EPU进一步交联，使分子间作用力进一步增大．DMTA分析表明，螯合物中有两个玻璃化转变温度tg，且tg明显增大，耐热性能显著提高。结构分析表明，一个Gd^3 与三个漆酚单元配位．     

两种铯的水杨酸化合物的合成与表征

一直以来,水杨酸(2-羟基苯甲酸)及其衍生物被认为具有抗肿瘤活性,将水杨酸及其衍生物制成各种金属化合物,它们的活性会大大增强。通常人们对碱金属Na 、K 研究的比较多,原因是它们在生物体中大量存在。近年来,人们对稀碱金属Rb 、Cs 日益感兴趣,主要在于Rb 、Cs 的生物必需性及     

Synthesis and characterization of the intermetallic compound NiSbS

The results recently obtained by our group to get new thermoelectric materials belonging to the M–Pn–Ch ternary systems (M=Co, Fe, Ni; Pn=P, As, Sb, Ch=S, Se, Te) are here reported. We have considered the Ni–Sb–S ternary system, and some homogeneous samples of composition near to 1:1:1 were prepared employing a new and simple synthetic route, starting from pure elements. Scanning electronic microscopy, electron-probe microanalysis and X-ray powder diffraction were used to investigate the microstructure. The NiSbS lattice parameters were determined and the crystal structure was refined by Rietveld method. The crystal cell of NiSbS belongs to the P213 space group with a = 0.5931 nm. The thermal stability of the ternary compounds Ni–Sb–S was investigated by DSC technique. Electrical resistivity and thermoelectric power measurements at room temperature and at 77 K were performed on platelets obtained by cleavage of the bulk.     

Synthesis, characterization, and reaction of a ketone-derived 1,4-dienolate compound

The tetrahydrofuran tetrasolvated dimeric lithium dienolate derived from 2,2,7,7-tetramethyloctan-3,6-dione is characterized in the solid state by X-ray diffraction analysis and in solution by diffusion NMR. This dienolate was reacted with tropanone to yield two new products that are also described.     

Preparation and characterization of Mg-Al hydrotalcite-like compounds containing cerium

Hydrotalcite-like compounds (HTlcs) containing Mg(2+), Al(3+), and Ce(3+) in the hydroxide layer and with carbonate as charge-balancing anion have been prepared by a co-precipitation (at constant pH) method. The Al/Ce ratio in the final product depends on the concentration in the initial solution. The crystallinity of the layered materials decreases with the increase in cerium content, probably, due to the distortions introduced by the large difference in the ionic radii of the cations. All the synthesized materials were characterized by XRD, FT-IR spectroscopy and TG/DTA. The textural properties were determined from low-temperature nitrogen adsorption-desorption measurements.     

Synthesis and structural characterization of the novel cluster compound

Reaction of [Mo3Y(mu-S)3(dtp)4(H2O)] (Y = O, S; dtp = S2P(OC2H5)2(-)) with HgI2 gave the novel compound [[Mo3S7(dtp)3]4 x I][(HgI3)3] x 4H2O (1), which contains a [[Mo3S7(dtp)3]4 x I] tetramer and (HgI3)-. Compound 1 has been characterized by IR, Raman, UV/Vis, and NMR spectroscopy and single-crystal X-ray diffraction analysis. It is shown that this formation process can be referred to as a new cluster reaction. The structure and spectroscopic data of the tetramer is also compared with that of the related discrete cluster [Mo3S7(dtp)3 x I]. Crystal data: space group F23, a = 26.786(3) A, V = 19218.7(4) A3, Z = 4, R = 0.059.     

Synthesis, characterization and catalytic activity of a Wilkinson's type metal-organic-polyoxometalate hybrid compound

A metal-organic-polyoxometalate hybrid compound with two functional centers consisting of a rhodium(I)bis(diphenylphospine) unit connected through two alkylene bridging groups to a lacunary Keggin type polyoxometalate was synthesized and used as an effective, recyclable hydrogenation catalyst in monophasic and aqueous biphasic reaction modes.     

Intercalation of iron(III) hexacyano complex in a Ni,Al hydrotalcite-like compound

The product obtained by the intercalation of hexacyanoferrate(III) inside a Ni, Al hydrotalcite-like compound (Htlc) has been characterized using XRD, FT-IR, Raman, and XAS spectroscopy. The intercalation was carried out by anionic exchange of the originally existing chloride ions. The combined use of those techniques gave more insight on the insertion chemistry of Htlcs. Extended X-ray absorption fine structure spectra of the intercalated Htlc demonstrated that the native structure was stable during the iron complex insertion, whereas the exchange process occurred with a partial reduction of hexacyanoferrate(III). Both Raman and FT-IR spectroscopy pointed out the concomitant formation of K(2)NiFe(II)(CN)(6) and KNiFe(III)(CN)(6). The effect of aging on the intercalated product is also addressed.     

Thixotropic properties of aqueous suspensions containing cationic starch and aluminum magnesium hydrotalcite-like compound

The rheological properties of aqueous suspensions consisting of cationic starch (CS) and positively charged aluminum magnesium hydrotalcite-like compound (HTlc) were investigated. Special emphasis was placed on the thixotropic phenomena. With the increase of mass ratio (R) of HTlc to CS, the equilibrium viscosity (eta(eq)) and the consistency coefficient (m) values of the suspensions increase in the range of neutral and alkaline pH (higher than 6.5) while decrease in the range of acid pH (lower than 6.5). With the increase of pH value, the eta(eq) and m values of the suspensions in the R range of 0-0.08 studied increase initially and then decrease, appearing a maximum value at about pH 7.41+/-0.25. The CS/HTlc suspensions display viscid character and the yield point of the suspensions was not observed except the suspension with R=0.08 in the pH range of 7.66-9.70, which showed a yield point and viscoelasticity. The CS/HTlc suspensions may display different thixotropic types: negative, complex or positive thixotropy, depending on pH and R value. The thixotropic type of the CS/HTlc suspension may be transformed from negative (pure CS solution), through complex (R=0.02), into positive thixotropy (R=0.05 and 0.08) with the increase of R in the studied R range of 0-0.08, and the thixotropic strength of the suspensions increases initially and then decreases with pH value in the pH range studied. The mechanism of the thixotropic phenomenon is discussed.     

镍铁类水滑石对偶氮阴离子染料的吸附脱色作用

采用镍铁类水滑石作为吸附剂,对偶氮阴离子染料酸性大红G、活性艳红X-3B和直接耐酸大红4BS废水进行脱色处理,研究了时间、镍与铁的物质的量之比、初始pH和无机电解质添加剂等因素对脱色率的影响,并结合红外光谱和X射线衍射分析结果讨论了其吸附脱色机理.结果表明,三种染料在镍铁类水滑石上的吸附均为层间的阴离子交换吸附和外表面的吸附.通过阴离子交换进入层间后,不同于直接耐酸大红4BS阴离子,酸性大红G和活性艳红X-3B两种阴离子与水滑石层间水分子之间产生氢键作用;在化学键合过程中,染料分子被镍铁类水滑石表面Fe3+氧化,同时偶氮键断裂导致脱色.     

Physicochemical characterization and adsorption behavior of calcined Zn/Al hydrotalcite-like compound (HTlc) towards removal of fluoride from aqueous solution

A Zn/Al hydrotalcite-like compound (HTlc) was prepared by co-precipitation (at constant pH) method and was characterized by XRD, TG/DTA, FTIR, and BET surface area. The ability of Zn/Al oxide to remove F- from aqueous solution was investigated. All the adsorption experiments were carried out as a function of time, pH, concentration of adsorbate, adsorbent dose, temperature etc. It was found that the maximum adsorption takes place within 4 h at pH 6.0. The percentage of adsorption increases with increase in the adsorbent dose, but decreases with increase in the adsorbate concentration. From the temperature variation it was found that the percentage of adsorption decreases with increase in temperature, which shows that the adsorption process is exothermic in nature. The adsorption data fitted well into the linearly transformed Langmuir equation. Sulfate and phosphate were found to have profound effects on fluoride removal. Thermodynamic parameters such as DeltaG0, DeltaH0, and DeltaS0 were calculated. The negative value of DeltaH0 indicates that the adsorption process is exothermic. The apparent equilibrium constants (Ka) are also calculated and found to decrease with increase in temperature. With 0.01 M NaOH the adsorbed F- could be completely desorbed from Zn/Al oxide in 6 h.     

3,4-二羟基苯甲酸镉配合物的合成,结构表征及荧光性质

采用碳酸镉和3,4-二羟基苯甲酸、2,2’-联吡啶合反应得到了配位聚合物[Cd(C7H5O4)2·(H2O)3·2H2O(1).采用元素分析、红外光谱、荧光光谱对配合物进行了表征.用X射线单晶衍射仪测定了配合物的晶体结构.配合物为单斜晶系,P2(1)/c空间群,昌胞参数Z=4,a=0.78338(8)nm,b=1.98...     

Synthesis, spectral and solid state characterization of a new bioactive hydrazine bridged cyclic diphosphonium compound

The facile preparation of a racemic hydrazine bridged diphosphonium compound possessing a ring system analogous to bicyclo[3.3.2]decane is reported. Although the reaction yield is low, the structure of the compound, which possesses an eight-membered ring, two phosphonium cationic centers, a biimino bridge, molecular chirality and two fused aromatic rings locked into roughly perpendicular planes is unusual. The compound displays substantial biological activity in the brine shrimp test and cleaves plasmid DNA.     

Electrochemical characterization of carbon paste electrodes modified with MgZnGa and ZnGaAl hydrotalcite-like compounds

Two hydrotalcite-like compounds (HTs) were synthesized by coprecipitation. The electrochemical behavior of MgZnGa ([Mg_0.58 Zn_0.17Ga_0.25 (OH)₂] (CO₃)^2? _0.125 1.5 H₂O) and ZnGaAl ([Zn_0.75Ga_0.19 Al_0.06 (OH)₂] (CO₃)^2? _0.125·1.5 H₂O) Hydrotalcite-like compounds (HTs) was studied in NaOH at different concentrations. Voltammetric and chronoamperometric studies were performed to identify oxidation and reduction processes and the effect of the cations in total reactivity. Electrocatalytic effect of HTs on hydroxide electrochemical oxidation shows better performance of MgZnGa; this is apparently due to the presence of Mg and a greater amount of Ga³⁺ in the lattice of this HT. As far as reduction is concerned, Zn(II) reduction process is observed within the lattices of both HTs and is influenced by both the amount of OH^? in the solution and the potential which the previous oxidation has been performed.