Synthesis, characterization, and sorption properties of amorphous titanium phosphate and silica-modified titanium phosphates

Amorphous titanium hydroxyphosphate with formula Ti(OH)(1.36)(HPO(4))(1.32).2.3H(2)O and a new silica-modified titanium hydroxyphosphate with a general formula Ti(OH)(2x)(HPO(4))(2-x).ySiO(2).nH(2)O are synthesized and characterized using IR, TG, XRD, SEM, solid-state NMR, and BET techniques. It is concluded that SiO(2) is evenly distributed within the titanium phosphate (TiP) agglomerates and that neither the separate silica phase nor the titanium silicates are formed during the synthesis of silica-modified titanium hydroxyphosphate. Correlations between the texture, ion-exchange properties of the amorphous titanium hydroxyphosphate, and the amount of SiO(2) present within the TiP matrix are established. Sorption properties of silica-modified titanium hydroxyphosphate toward Cs(+) and Sr(2+) are studied in a series of samples with an increasing amount of silica, at different pH, and in NaCl solutions with a varying ionic strength. It is found that sorption of Cs(+) does not depend practically on the amount of SiO(2) present, whereas the Sr(2+) uptake drastically decreases with an increase of silica amount. The effects of pH and of the electrolyte concentration on the sorption behavior of titanium phosphate are discussed in terms of ionic hydration shell and titanium phosphate structural specificity. The kinetics of sorption processes is also investigated, and the diffusion coefficients for cesium and strontium are obtained.     

Synthesis,characterization and electrochemical properties of a compact titanium dioxide layer

In this paper, we report on the synthesis, characterization, and electrochemical properties of a compact titanium dioxide layer as well as its application in dye-sensitized solar cells (DSCs). The compact TiO₂ layer, which was prepared via a facile approach by the hydrolysis of TiCl₄ aqueous solution, has been characterized by XRD, SEM, UV–vis absorption spectroscopy, voltammetry, and electrochemical impedance spectroscopy (EIS). Experimental results show that the compact TiO₂ layer with the thickness of about 100 nm is composed of anatase-phase nanoparticles with the particle size of 10–15 nm. Impedance measurements display that the compact layer of TiO₂ can prevent the back reaction of electrons with tri-iodide ions under low applied potentials, increase the open circuit voltage (V_oc) and fill factor (FF), and finally improve the conversion efficiency (η) for the DSCs from 7.5 to 8.1%.     

Polyamide-bound metal complex catalysts: Synthesis,characterization and catalytic properties

A series of polyamides having different numbers of methylene groups in their repeating units have been synthesized by interfacial polycondensation of terephthaloyl chloride with piperazine and aliphatic diamines H₂N(CH₂)_nNH₂ (n = 2, 6, 10). These materials, which have high thermal stability, were used for immobilization of rhodium and platinum complexes. Chloroplatinic acid and the compounds PtCl₂(CH₃CN)₂ and [RhCl(CO)₂]₂ were used as precursors of the supported catalysts. Low molecular weight analogues of the polyamides were prepared for a study of the coordination mode between the metal ion and the polymer by IR spectroscopy. The results suggest that the carbonyl oxygen of the polyamide is the site of coordination to both rhodium and platinum. The bound catalysts exhibited high activity in hydrosilylation of hexene-1. The activities of the rhodium complexes were found to be dependent on the structure of the polyamide support, decreasing with increasing distance between the amide groups, and closely paralled the changes in the degree of crystallinity of the polymers. Repeated use of the polymers bearing rhodium complexes showed that the bond between the metal and polyamide is fairly stable.     

Alkali (alkaline-earth) metal,aluminum, and titanium complex orthophosphates: Synthesis and characterization

Phase formation in the A_{1 + x} Al _x Ti_{2 ? x} P₃O₁₂ (A = Li, Na, K, Rb, or Cs; 0 ≤ x ≤ 2.0) and B_{0.5(l + x)}Al _x Ti_{2 ? x} P₃O₁₂ (B = Mg, Ca, Sr, or Ba; 0 ≤ x ≤ 2.0) systems was studied using X-ray powder diffraction, electron probe microanalysis, and IR spectroscopy. The following double and triple orthophosphates were found to exist: A_{1 + x} Al _x Ti_{2 ? x} (PO₄)₃ with A = Li (0 ≤ x ≤ 0.3), Na (0 ≤ x ≤ 1.0), K (x = 0, 1.0, or 2.0), Rb (x = 0, 1.0, or 2.0), or Cs (0 ≤ x ≤ 1.0) and B_{0.5(l + x)}Al _x Ti_{2 ? x} (PO₄)₃ with B = Mg and Ba (x = 0), Ca and Sr (0 ≤ x ≤ 0.2). These orthophosphates crystallize in the structure types of kosnarite, langbeinite, cesium titanium arsenate, potassium aluminum phosphate, or rubidium aluminum phosphate. Their crystal parameters were calculated. For CsTi₂(PO₄)₃ (x = 0), Rietveld refinement was carried out: space group Ia \(\bar 3\) d, Z = 32, a = 19.909(5) Å, V = 7892(1) ų. This compound has a framework structure. The framework is built of TiO₆ octahedra and PO₄ tetrahedra; eight- and 12-coordinated Cs⁺ cations populate interstices.     

Synthesis,characterization, and magnetic properties of mixed-valence europium-ammonia intercalation compounds of titanium disulfide

Europium-ammonia intercalation compounds of titanium disulfide have been synthesized by reaction of EuNH₃ solutions with TiS₂, characterized by thermogravimetric analysis and powder X-ray diffraction, and investigated by electron paramagnetic resonance, magnetization, and magnetic susceptibility measurements. These materials crystallize in a 3R-type structure in which every layer is occupied by intercalated species. The intercalation of NH₃ is accompanied by the formation of NH⁺₄ until a critical electron concentration of 0.22 mole el/mole TiS₂ have been transferred to the TiS₂ conduction band. Although Eu³⁺ is the predominant Eu species for x > 0.001, Eu²⁺ is also formed, possibly from the reduction of Eu³⁺ in the van der Waals gap. These mixed-valence compounds are best described by the formulas (Eu³⁺)_x′(Eu²⁺)_x″(NH⁺₄)_y′(NH₃)_y″TiS^{(3x′+2y″+y′)−}₂ for 3x′ + 2x″ + y′ < 0.22 and (Eu³⁺)_x′(Eu²⁺)_x″(NH₃)_y″TiS^{(3x′+2x″)−}_n2 for 3x′ + 2x″ ≥ 0.22.     

Synthesis,spectroscopic characterization and redox properties of titanium and vanadium substituted Keggin-type heteropolyanions

The Ti-substituted heteropolytungstates K7[TiIVW11–BO40] and K6[VVTiIVW10PO40] have been synthesized and characterized by elemental analyses and spectroscopic techniques. Their redox properties have been studied by cyclic voltammetry, and the compounds were found to be more difficult to reduce than the unsubstituted heteropolyanion. The one- and two-electron reduced heteropoly blues of [VVTiIVW10PO40]6–, namely [VIVTiIVW10PO40]7– and [VIVTiIIIW10PO40]8–, have also been prepared by chemical methods. Their optical spectra show low-energy intervalence charge-transfer bands as well as the expected d–d transitions. The optical and e.s.r. investigations indicate that VIV and TiIII are not vicinal in [VIVTiIIIW10PO40]8–.     

Synthesis,characterization and metal chelating properties of silica-physisorbed and chemisorbed-2,5-dioxypiperazine

2,5-Dioxypiperazine (DOPZ) was covalenty bonded as a chelating compound to chloropropyltrimethoxysilane (Si–Cl) for the formation of a new chemisorbed silica [Si–(CH₂)₃–DOPZ]. Physisorbed silica-loaded-2,5-dioxypiperazine [Si–DOPZ] was also synthesized via a physical adsorption approach. Elucidation of the chemisorption and physisorption of 2,5-dioxypiperazine onto silica was confirmed on the basis of 70 eV electron impact mass spectrometric (70 eV EI-MS) mode of ionization via a direct insertion probe (DIP) as a promising technique for providing characteristic fragment ion peaks. The metal probe testing method and elemental analysis were applied to determine the surface coverage values and these were found to be 0.179 and 0.160 mmol g⁻¹ for [Si–(CH₂)₃–DOPZ] and 0.251 mmol g⁻¹ for [Si–DOPZ]. [Si–(CH₂)₃–DOPZ] was characterized by high stability in acidic and buffer solutions, pH 1–7, compared to [Si–DOPZ]. Differential scanning calorimetry studies (DSC) for the modified silica were performed to evaluate the various thermodynamic and kinetic parameters of the thermal degradation processes, and these have been enumerated. The results obtained by both EI-MS and DSC are very similar in many respects. Metal chelation and stoichiometric properties of chemically modified silica were evaluated on the basis of the metal binding capacity, distribution coefficient and separation factor for a series of metal ions. The evaluated results refer to the high metal chelating properties of [Si–(CH₂)₃–DOPZ] for cadmium(II), lead(II) copper(II) and mercury(II). These four [Si–(CH₂)₃–DOPZ]–metal complexes were also synthesized and the identified stoichiometric ratios were found to be 1:2 based on the nitrogen and metal analysis. EI-MS via 70-eV ionization was also used as a potential method for further confirmation of the metal complex formation based on structure and fragmentation elucidation. DSC studies of these four metal complexes were also performed and evaluated.     

Synthesis and characterization of ferrocenyl-acridine dyads and their multiresponse to proton and metal cations

Two new π-conjugated linked ferrocenyl-acridine dyads, (9-ethynylferrocenyl)acridine (3a) and (1-(ferrocenylethynyl)-4-ethynylbenzenyl)-acridine (3b), have been synthesized and investigated. UV-Vis spectroscopic and electrochemical studies reveal that 3a offers stronger electronic communication between terminal subunits than the extended system 3b, as shown by a stronger and lower-energy metal-to-ligand charge transfer (MLCT) transition and a more positive redox potential. Both of 3a and 3b show multiresponse to protons and selected metal ions (M = Zn²⁺, Pb²⁺, Hg²⁺, Fe³⁺, Cr³⁺), with a MLCT transition shift to the lower-energy, a redox potential shift to anode, and a luminescence increasing.     

Synthesis,characterization and properties of polyaniline doped with transition metal substituted silicotungstate

Polyaniline hybrid material doped with transition metal mono-substituted silicotungstate β₂-K₆[SiW₁₁M(H₂O)O₃₉]?·?xH₂O (M?=?Mn²⁺, Co²⁺, Cu²⁺, Fe²⁺) were prepared for the first time. Their scanning electron microscopy (SEM), infrared (IR), UV–Vis, and X-ray diffraction (XRD) patterns confirm the existence of Keggin anions and form the space reticular structure. The material exhibits excellent proton conduction, its proton conductivity is 9?×?10^?2?s?cm^?1 at room temperature (20°C).     

Synthesis,structural characterization,and photocatalytic study of transition metal coordination polymers constructed from mixed ligands

Three 3-D coordination polymers, [Cu(cca)(4,4′-bipy)]_n (1), [Co₃(pda)₃(1,10′-phen)₂]_n (2), and [Co(pda)(1,10′-phen)]_n (3), have been synthesized from 4-carboxycinnamic acid (cca), 1,4′-phenylenediacrylic acid (pda), 4,4′-bipyridine (4,4′-bipy), 1,10′-phenanthroline (1,10′-phen), and Cu and Co salts under different conditions. The X-ray crystal structures of these three complexes are presented. Complex 1 exhibits a threefold 3-D α-Po interpenetration network. Complex 2 with a 3-D framework with six-connected single α-Po framework constructed from Co₃ unit has been synthesized and characterized. Complex 3 shows a 3-D framework with bcu topology composed of 1-D rod-shaped secondary building units. Furthermore, the photocatalytic properties of 2 were studied. When excited by UV light, 2 exhibits photocatalytic activity, in 300?min, about 71% Rhodamine B decomposes.     

Synthesis,characterization, thermal,and redox properties of a vic-dioxime and its metal complexes

A new vic-dioxime ligand containing benzophenone hydrazone units, N′-(benzophenone hydrazone)glyoxime [LH₂] has been prepared from benzophenone hydrazone and anti-chloroglyoxime in absolute ethanol. Mononuclear nickel(II), cobalt(II), copper(II), zinc(II), and cadmium(II) complexes were also synthesized. Ligand and complexes were characterized by elemental analyses, FT-IR, ¹H NMR, and ¹³C NMR spectroscopy, magnetic moments, and DTA/TG techniques. On the basis of the magnetic and spectral evidences a square-planar geometry for Ni(II) and Cu(II) complexes, tetrahedral for Cd(II) and Zn(II) complexes, and octahedral for Co(II) complex were proposed. Redox behaviors of ligand and its complexes were also investigated by cyclic voltammetry at the glassy carbon electrode.     

Synthesis,crystal structure and properties of thiaheterohelicenes containing phenolic hydroxy functions

A convenient method for preparation of dimethoxythiahelicene 4 and dihydroxythiahelicene 5 is described; these helical molecules showed self-assembling properties such as enantiomorphic crystal growth and clathrate formation.     

Synthesis,characterization and redox properties of a new vic-dioxime and its transition metal complexes

A novel vic-dioxime, 1,2 dihydroxyimino-1-p-tolyl-3-aza-6-morpholine heptane (LH₂) was prepared by reacting anti-p-tolylchloroglyoxime with 4-(3-aminopropyl)morpholine in absolute THF. Mononuclear complexes with a metal–ligand ratio of 1:2 were prepared using Co^II, Cu^II and Ni^II salts. The ligand and its complexes were characterized by elemental analyses, FT-IR, u.v.–vis., ¹H- and ¹³C-n.m.r. spectra, magnetic susceptibility measurements, thermogravimetric analyses (t.g.a.), and by cyclic voltammetry.     

Synthesis, structure and magnetic behaviour of mixed metal leucophosphite

A synthetic analogue of leucophosphite, an iron phosphate, was synthesized hydrothermally at 180 °C and its chemical composition determined to be {K[(FeV)(PO₄)₂(OH)(H₂O)]·H₂O}. The compound crystallizes in the monoclinic P2₁/c space group, with a=9.7210(19) Å, b=9.6500(19) Å, c=12.198(4) Å and β=128.569(18)°. While the original all-iron compound is reported to be antiferromagnetic, the inclusion of substitutional vanadium(III) ions renders the structure ferrimagnetic. Diffraction studies and magnetic characterization show that iron and vanadium are disordered throughout the crystallographic sites. The magnetic behaviour of this system was interpreted in terms of a classic ferrimagnetic mean field model, consisting of two antiferromagnetically coupled non-crystallographic “sublattices”.     

Synthesis and properties of hydroxy tail-terminated cyanobiphenyl liquid crystals

Two series of new hydroxy tail-terminated cyanobiphenyl compounds are described. The 4′-ω-hydroxyalkynyl-4-cyanobiphenyl compounds (1a–1g) were synthesised as the key intermediates to the 4′-?ω-hydroxyalkyl-4-cyanobiphenyl compounds (2a–2g) obtained upon reduction of the acetylenes. Many of these ω-hydroxyalkynyl and ω-hydroxyalkyl cyanobiphenyl compounds exhibit nematic mesophases and they also serve as precursors for the synthesis of other interesting materials. Using density functional theory, we calculate the dipole moment of all relevant ω-hydroxyalkynyl and ω-hydroxyalkyl cyanobiphenyl compounds and find a correlation between the calculated dipole moments and measured crystalline to nematic or isotropic liquid transition temperatures.     

Synthesis,characterization, crystal structures,and magnetic properties of two new dissymmetrical Schiff-base metal complexes

Two dissymmetrical Schiff-base metal complexes, [CuL1]₂ (1) (L1 = N-3-carboxylsalicylidene-N-5-bromosalicylaldehyde-1,3-diaminopentane) and [NiL2] · H₂O (2) (L2 = N-5-bromosalicylaldehyde-1,3-diaminopentane), have been synthesized and characterized by IR, elemental analyses, magnetic studies, and the crystal structures. The crystal structure of 1 contains one binuclear molecule in which each central Cu has N₂O₃ coordination. The magnetism of 1 has been determined in the temperature range of 5–300 K. Results indicate that interaction between the two Cu ions is weak antiferromagnetic. The crystal structure of 2 shows mononuclear structure with similar structural features. Through intermolecular hydrogen-bonding interactions, 2 gives an infinite chain structure.     

二氧化钛介孔分子筛的合成和表征

以高嵌段共聚物为模板剂在中性条件下制备二氧化钛介孔分子筛,并以TG-DTA,XRD,TEM和N~2吸附方法对脱除模板剂后的样品进行了表征。实验结果表明,该介孔分子筛具有较高的比表面,以及六方堆积的均匀孔道,焙烧过程中孔壁可部分晶化成锐钛矿型TiO~2的小晶粒。在分子筛孔壁中引入稀土元素可提高介孔结构稳定性。     

Synthesis, characterization and antitumour properties of metal(II) solid complexes with Morin

Summary Six metal(II) complexes with Morin ML₂·nH₂O [L = Morin(2-OH group deprotonated); M = Mn, Co, Ni, Cu, Zn, or Cd; n = 2 or 3] have been synthesized and characterized by elemental analysis, molar conductance, i.r., ¹H-n.m.r., t.g.-d.t.a and u.v.-vis. spectroscopic techniques and by fluorescence analysis. Comparative antitumour activities of Morin·2H₂O and two complexes [ZnL₂·3H₂O and CuL₂·2H₂O] were tested by in vitro screening. The results show that the inhibitory ratio of complexes against the tested tumour cells was higher than that of Morin.     

Synthesis, characterization and thermal properties of metal-containing polyurethane-ureas from hexadentate Schiff base metal complexes

Metal-containing polyurethane-ureas and copolyurethane-ureas have been synthesized by the reaction between hexadentate Schiff base metal complexes and isocyanate-terminated prepolymers. The metal complexes employed were MSal₂trien, where (M=Ni and Zn, Sal=salicylaldehyde and trien=triethylenetetramine). The NCO-terminated prepolymers used were tolylene 2,4-diisocyanate terminated poly(1,4-butanediol) (PB), tolylene 2,4-diisocyanate terminated poly(propylene glycol) (PP) prepolymers and the prepolymers synthesized from 4,4^′-diphenylmethane diisocyanate (MDI) and diols. The diols employed were polycaprolactone diol (PCL) and poly(tetramethylene oxide) (PTMO). Copolyurethane-ureas were synthesized by the reaction between MSal₂trien, PB or PP prepolymers and MDI. Characterizations of polymers were carried out using IR spectroscopy, elemental analysis, solubility and viscosity. Flammability of polymers was investigated by measuring limiting oxygen index (LOI) values and thermal stability was studied by thermogravimetric analysis (TGA).