[Preparation and spectral characterisation of TiO2/polyaniline nanocomposites with 2D lamellar morphology].

Nanostructured polyanilines (PANIs) are selected quite often as the matrix for the synthesis of inorganic/conductive polymer composites due to their excellent optical, electrical and magnetic properties. Herein both 2D lamellar PANI and the cor responding composite loading TiO2 species were successfully prepared from a microemulsion system, as composed by dodecyl benzenesulfonic acid (DBSA) and water. The composite was achieved through a simultaneous polymerization of aniline in the presence of ammonium persulfate and hydrolysis of tetrabutyl titanate. Scanning electron microscopy (SEM) images indicate clearly that 2D PANI lamella are formed through organization of small PANI sheets. The inter-lamellar distance of PANI and that of TiO2/polyaniline composite, as derived from X-ray diffraction (XRD), is about 3.4 nm (nearly twice the length of one DBS molecule), suggesting that PANI and double-layered DBSA species are arranged in an alternated way. FTIR spectrum displays that PANI chains exhibit quinonoid and benzenoid strutures while both Raman and X-ray photoelectron spectroscopy (XPS) indicate that rutile TiO2 is produced upon hydrolyzation of tetrabutyl titanate in the microemulsion system. Moreover, UV-Vis spectrum suggests that the electronic absorption behaviour of PANI species is influenced upon loading TiO2.

[Spectroscopic analysis studies of organo-attapulgite/nylon 6 composites].

The surface organic modification of attapulgite with silane coupling reagent was studied by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Qrgano-attapulgite/nylon 6 composites with different content of attapulgite were prepared by means of melt blending, and the crystal structure and morphology were investigated. The results show that the surface content of Si, N and C of the modified attapulgite increased. Combined with the FTIR results, it was confirmed that an organic coating layer was formed on the surface of attapulgite. The adding of attapulgite does not change the crystal structure of nylon 6, but changes the crystallite size of nylon 6. The modified attapulgite was well dispersed in nylon 6 and the silane coupling coating on the attapilgite enhanced the interfacial adhesion.

[Preparation of microencapsulated red phosphorus and its flame-retardant application in PP composites].

In the present study, the melamine-formaldehyde prepolymer (MFP) was first synthesized at pH 8-8.5 under about 80 degrees C with melamine, formaldehyde, triethanolamine and methanol as the starting materials. Subsequently, the microencapsulated red phosphorus (MRP) was successfully prepared by in-situ polymerization at pH 5.5 under 65 degrees C, using MFP and red phosphorus (RP) powders as raw materials, and potassium persulphate (KPS) as catalyst. The obtained products were detected by differential scan calorimetry (DSC), scanning electron microscope (SEM), Fourier transform infrared (FTIR) and X-ray photo-electron spectroscopy (XPS). It was found that KPS is useful in enhancing the reaction activity of MFP, which can make RP be well encapsulated by melamine-formaldehyde resin (MF) and reduce the reaction time. The DSC, SEM and XPS results show that it won't get well-encapsulated MRP only under acidic condition and without any KPS. When a proper quantity of KPS is employed, the RP particles can be almost completely-encapsulated by MF and the peak temperature of oxidation reaction for MRP is 480 degrees C, which is much higher than that of RP, extending the applications for MRP. The FTIR spectrum demonstrates that the coating material on the surface of RP accurately is MF, in agreement with the reference. Polyproplene (PP) composites with different formulations were prepared by melt extrusion. It was shown that the flame-retardant efficiencies are very low when the PP composites only contain MRP or MH. However, the flame-retardant property can obviously improve if MRP and MH are both used in the PP composites. When PP : MRP: MH = 100 (phr) : 15 (phr) : 50 (phr), the limited oxygen index of the MRP/MH/PP composite is 26%, and vertical firing ranks UL-94 V-0. In addition, the possible flame-retardant mechanism of the PP composites has also been discussed, and further verified by FTIR and Raman spectroscopy.

Vibrational spectroscopic study of o-, m- and p-hydroxybenzylideneaminoantipyrines.

Three structurally similar antipyrine derivatives of o-hydroxybenzylideneaminoantipyrine (o-HBAP), m-hydroxybenzylideneaminoantipyrine (m-HBAP) and p-hydroxybenzylideneaminoantipyrine (p-HBAP) were characterized by FT-IR, FT-Raman experimental techniques and density functional theoretical (DFT) calculations. The comparisons between the calculated and experimental results covering molecular structures, assignments of fundamental vibrational modes and thermodynamic properties were investigated. The optimized molecular geometries agree well with the corresponding experimental values by comparing with the XRD data. The comparisons and assignments of the vibrational frequencies indicate that the experimental spectra also coincide satisfactorily with those of theoretically simulated spectrograms except the hydrogen-bond coupling infrared vibrations, and compounds can be distinguished by the IR and Raman spectra due to the differences of the hydroxyl-substituted positions and molecular packing, and the strong Raman scattering activities of the compounds are tightly relative to the molecular conjugative moieties linked through the Schiff base imines. The thermodynamic functions and their correlations with temperatures were also obtained from the theoretical harmonic frequencies.

Hydrogen-bond-directed supramolecular arrays in 4,4'-bipyridinium tetrachloroterephthalate dihydrate and bis(1,10-phenanthrolinium) tetrachloroterephthalate tetrachloroterephthalic acid trihydrate.

The title compounds, C10H10N(2)(2+).C8Cl4O(4)(2-).2H2O, (I), and 2C12H9N2+.C8Cl4O(4)(2-).C8H2Cl4O4.3H2O, (II), both crystallize as charge-transfer organic salts with the dianionic or neutral acid components lying on inversion centres. The acid and base subunits in (I) arrange alternately to generate a linear tape motif via N-H...O hydrogen bonds; these tapes are further combined into a three-dimensional architecture through multiple O-H...O and C-H...O interactions involving solvent water molecules. In contrast, the neutral and anionic acid components in (II) are linked to form a zigzag chain by means of O-H...O hydrogen bonds between acid groups, with dangling 1,10-phenanthrolinium units connected to these chains by carboxylate-pyridinium interactions with R(2)(2)(7) hydrogen-bond notation. Adjacent chains are further extended to result in a two-dimensional corrugated layer network via pi-pi interactions. Inter-ion Cl...O interactions are also found in both (I) and (II).

Experimental and theoretical studies on 4-(2,4-dichlorobenzylideneamino)antipyrine and 4-(2,6-dichlorobenzylideneamino)antipyrine.

Two antipyrine derivates, with the same formula C(18)H(15)Cl(2)N(3)O, are structurally similar Schiff bases derived from the condensation of 2,4-dichlorobenzaldehyde or 2,6-dichlorobenzaldehyde and 4-aminoantipyrine in methanol solutions. The compounds were characterized by elemental analysis, FT-IR, FT-Raman and UV-vis techniques. Density functional calculations were performed to further optimize and characterize them. The calculated results indicate that the theoretical values show good agreements with experimental ones. They are similar in their IR spectra and different in their Raman spectra. The detailed vibrational and UV-vis absorption spectra of the compounds have been ascribed to their corresponding molecular structures and electrons orbital transitions. The statistical thermodynamic functions and their correlations with temperatures of the title compounds have been obtained from their theoretical vibrations of the optimized structures. The nonlinear optical and UV-vis properties indicate that the compounds are the promising photoelectronic materials.

Experimental and theoretical studies on vibrational spectra of 4-(2-furanylmethyleneamino)antipyrine, 4-benzylideneaminoantipyrine and 4-cinnamilideneaminoantipyrine.

This work deals with the IR and Raman spectroscopy of 4-(2-furanylmethyleneamino) antipyrine (FAP), 4-benzylideneaminoantipyrine (BAP) and 4-cinnamilideneaminoantipyrine (CAP) by means of experimental and quantum chemical calculations. The equilibrium geometries, harmonic frequencies, infrared intensities and Raman scattering activities were calculated by density functional B3LYP method with the 6-31G(d) basis set. The comparisons between the calculated and experimental results covering molecular structures, assignments of fundamental vibrational modes and thermodynamic properties were investigated. The optimized molecular geometries have been compared with the experimental data obtained from XRD data, which indicates that the theoretical results agree well with the corresponding experimental values. For the three compounds, comparisons and assignments of the vibrational frequencies indicate that the calculated frequencies are close to the experimental data, and the IR spectra are comparable with some slight differences, whereas the Raman spectra are different clearly and the strongest Raman scattering actives are relative tightly to the molecular conjugative moieties linked through their Schiff base imines. The thermodynamic properties (heat capacities, entropies and enthalpy changes) and their correlations with temperatures were also obtained from the harmonic frequencies of the optimized structures.

[Study on the preparation and spectral characteristics of Bi2S3 nanoribbons].

In the present study, bismuth sulfide (Bi2S3) nanoribbons were prepared by the hydrothermal method using bismuth nitrate (Bi(NO3)3 x 5H2O), thioacetamide (C2H5NS) and nitrilotriacetic acid (C6H9NO6) as raw materials at 180 degrees C for 12 h. The reaction time was largely reduced and the route has been unreported. The constituent, structure and morphology of the products were characterized by XRD, XPS and TEM, respectively. The powder X-ray diffraction (XRD) pattern shows that the Bi2S3 crystals belong to the orthorhombic phase (JCPDS:17-320) with calculated lattice constants a = 1.1106 nm, b = 1.0993 nm and c = 0.3892 nm, which are consistent with the reported values (a = 1.1149 nm, b = 1.1304 nm and c = 0.3981 nm). Transmission electron microscopic (TEM) studies reveal that the appearance of as-prepared Bi2S3 is nanoribbon-like with the typical width of about 100 nm; and the high-resolution transmission electron microscope (HRTEM) image shows that the crystal grows along the y axis. The quantification of X-ray photoelectron spectra (XPS) analysis peaks gives an atomic ratio of 2 : 3 for Bi : S, which is consistent with the given formula of Bi2S3. Furthermore, the Raman and UV-Vis spectra of the product were also studied. Compared with bulk Bi2S3 (236 cm(-1)), the Raman absorption band of the Bi2S3 nanoribbons (195 cm(-1)) red-shifts 41 cm(-1), which is because of the surface effect of nanomaterials. Furthermore, the product has absorption at the wavelength of about 450 nm in the UV-Vis region. The direct bang gap energy (Eg) was estimated to be about 1.58 eV(Eg of the bulk Bi2S3 is 1.3 eV), which indicates that the product has potential application in the optical and electrical areas.

Bis[2,6-bis-(4,5-dihydro-1H-imidazol-2-yl)pyridine]manganese(II) bis-(per-chlorate) acetonitrile solvate.

In the cation of the title compound, [Mn(C(11)H(13)N(5))(2)](ClO(4))(2)·CH(3)CN, the metal atom is located on a twofold rotation axis and is six-coordinated by six N atoms from two different 2,6-bis-(4,5-dihydro-1H-imidazol-2-yl)pyridine (bip) ligands in a distorted octahedral geometry. The O atoms of the perchlorate anions are disordered with occupancies in the ratio 0.593 (10):0.407 (10). In the crystal, mol-ecules are stabilized by two N-H⋯O hydrogen bonds, forming zigzag chains along the a axis, which are further inter-connected by N-H⋯O hydrogen bonds and π-π inter-actions [centroid-centroid distance = 3.50 (1) Å] into a three-dimensional network.

1,4-Bis(4,5-dihydro-1H-imidazol-2-yl)benzene-4-amino-benzene-sulfonic acid-water (1/2/2).

The asymmetric unit of the title compound, C(12)H(14)N(4)·2C(6)H(7)NO(3)S·2H(2)O, contains one half of a centrosymmetric 1,4-bis-(4,5-dihydro-1H-imidazol-2-yl)benzene (bib) molecule, one 4-amino-benzene-sulfonic acid molecule and one water mol-ecule. In the bib molecule, the imidazole ring adopts an envelope conformation. The benzene rings of bib and 4-aminobenzenesulfonic acid are oriented at a dihedral angle of 21.89 (4)°. In the crystal structure, inter-molecular N-H⋯O, O-H⋯N and O-H⋯O inter-actions link the mol-ecules into a three-dimensional network. Weak π-π contacts between the benzene and imidazole rings and between the benzene rings [centroid-centroid distances = 3.895 (1) and 3.833 (1) Å, respectively] may further stabilize the structure.

1,4-Bis(4,5-dihydro-1H-imidazol-2-yl)benzene-terephthalic acid-water (1/1/4).

The asymmetric unit of the title compound, C(12)H(14)N(4)·C(8)H(6)O(4)·4H(2)O, consists of one half of the 1,4-bis-(4,5-dihydro-1H-imidazol-2-yl)benzene (bib) mol-ecule, one half of the terephthalic acid (TA) mol-ecule and two water mol-ecules. Both the bib and the TA mol-ecules reside on crystallographic inversion centers, which coincide with the centroids of the respective benzene rings. The bib and the TA, together with the water mol-ecules, are linked through inter-molecular O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds, forming a three-dimensional network of stacked layers. Weak inter-molecular C-H⋯O contacts support the stability of the crystal structure.

2,3,5,6-Tetra-fluoro-1,4-bis-(2-pyridylmethyl-eneamino-meth-yl)benzene.

The title compound, C(20)H(14)F(4)N(4), is a flexible bis-pyridine-type ligand with an extended fluorinated spacer group between the two pyridyl functions. The centroid of the central aromatic ring is situated on a crystallographic center of inversion. The dihedral angle between the pyridine ring and the central benzene ring is 63.85 (9)°. The crystal structure exhibits inter-molecular C-H⋯F hydrogen-bonding inter-actions.

[Study on the preparation and spectral characteristics of nano-NiO].

The NiO nanoparticles with the size of 9-30 nm were prepared by solid state method using nickel acetate and sodium hydroxide as the raw materials, and Tween 80 as the dispersant. The structure, morphology, size, and infrared and UV-Vis spectra were characterized by XRD, TEM, FTIR and UV-Vis, respectively. The XRD and TEM revealed that the products are spherical with cubic structure. The infrared absorption band of the NiO nanoparticles (437 cm(-1)) red-shifts 47 cm(-1) compared with that of bulk NiO(484 cm(-1)). The UV-Vis optical absorption is related with the size of the particles. The bulk NiO has no absorption in the UV-Vis region, while the 10 nm NiO nanoparticles have stronger absorption observed at the wavelength about 309 nm, and the direct band gap energy is estimated to be about 4.2 eV which is obviously blue-shifted 0.55 eV compared to that of bulk NiO (3.65 eV). The surface effect and quantum size effect of the NiO nanoparticles indicated that the products will have potential application in the optical and electrical areas.

[XPS investigation on the modified nano-Al2O3 by surface grafting].

Steric hindrance layer can be established when the surfaces of nano-Al2O3 were grafted with polyacetal, which increased the dispersibility of the nano-particles as well as the compatibility between the particles and the resin matrix. Examination of X-ray photoelectron spectroscopy (XPS) demonstrated that the peak of Al(2p) on polyacetal grafted Al2O3 surfaces almost disappeared, while that of O(1s) increased. On the contrary, peak of C(1s) increased obviously. Results of fine scanning and deconvolution into multiple sub-peaks of C(1s) indicated that 61.92% of carbon on the surfaces of nano-Al2O3 was attributed to the grafting polyacetal. This shows that an effective modification layer formed on Al2O3 surfaces, and the grafting polyacetal was chemically bound with nano-Al2O3. Based on XPS and TG analysis, it is conjectured that the grafting polyacetal is mainly distributed on nano-Al2O3 surfaces.

[Fading spectrophotometric determination of heparin with brilliant cresyl blue].

A new fading spectrophotometric method for determining trace heparin is proposed in the present paper. In pH 3.0 Britton-Robinson (B-R) buffer solution, brilliant cresyl blue can react with heparin resulting in the decrease of absorbance of BCB at 592 nm. The conditions for the interaction were optimized, and the interferences of coexisting substances were investigated. Under the optimal conditions the reduction of the absorbance is proportional to the concentration of heparin in the range of 0.6-6.0 mg x L(-1) with the detection limit of 0.173 mg x L(-1). The molar absorptivity of the method was calculated to be 1.03 x 10(6) L x mol(-1) x cm(-1). The method has been applied to determine the heparin sodium injection solution with satisfactory results.