Synthesis, 5-hydroxytryptamine1A receptor affinity and docking studies of 3-[3-(4-aryl-1-piperazinyl)-propyl]-1H-indole derivatives

A series of 3-[3-(4-aryl-1-piperazinyl)-propyl]-1H-indole derivatives (12a-h) was synthesized and evaluated for binding affinity at the human 5-hydroxytryptamine(1A) receptor (5-HT(1A)R) compounds (12b) and (12h) showed the highest 5-HT(1A) receptor affinity (IC(50)=15 nM). Molecular docking studies with all the compounds in a homology model of 5-HT(1A) showed that the main interaction anchoring the ligand in the receptor was a charge-reinforced bond between the protonated nitrogen atom (N-4) of the piperazine ring and Aspartate(3.32).     

Super impact strength of blends prepared from regular HIPS and poly(butyl acrylate)‐block‐poly(styrene) obtained by RAFT polymerization

S‐allyl‐4‐methyldithiobenzoate was synthesized and used as a chain transfer agent for the RAFT polymerization of butyl acrylate to produce a functionalized acrylic rubber. A solution of 8 wt% of this functionalized rubber was prepared in styrene and polymerized to generate a material called acrylic rubber‐modified polystyrene (AMP) constituted by well‐dispersed particles of poly(butyl acrylate)‐block‐poly(styrene) into a polystyrene matrix. Impact strength of injection‐molded samples of AMP was measured and compared with the general purpose polystyrene (GPPS) and the high impact polystyrene (HIPS). AMP itself showed an impact strength value similar to GPPS; however, when AMP was blended with conventional HIPS, the resulting material exhibited an improvement of 76–91% as compared to HIPS by itself, without affecting negatively tensile properties. Transmission electron microscopy analysis revealed both kinds of dispersed phases, i.e. the typical salami particles of polybutadiene coming from HIPS (size: 0.5–2 µ) and small particles from poly(butyl acrylate)‐block‐poly(styrene) (size: ～50 nm). We clearly showed that such a bimodality of the particle size distribution caused the positive synergistic effect on impact strength. Copyright © 2011 John Wiley & Sons, Ltd.     

Insights into the role of D-A-π-A type pro-aromatic organic dyes with thieno[3,4-b]pyrazine as A acceptor group into dye-sensitized solar-cells. A TD-DFT/periodic DFT study

Time-dependent density functional theory (TD-DFT)/periodic DFT calculations were performed to determine the role of pro-aromatic organic D-A -π -A type dyes (the NL1-NL17 family) with Thieno[3,4-b]pyrazine (Tpy) as A acceptor group into dye-sensitized solar-cells (DSSC). This work presents a discussion of the ground and excited states of these dyes along with the aromaticity analysis and the electron injection step using a dye@(TiO₂)₇₂ model. The results suggest that the pro-aromatic behavior increases from the thiophene ring to the pyrazine when an acceptor π-bridge such as phenyl is used. This strong pro-aromaticity is also reflected in the electron injection step, studied using a 3x2 3 layer (TiO₂)₇₂ slab model. The resulting adsorption energies (ΔE_ads and ΔG_ads) and the electron injection (ΔG_inject) in the stablest coordination mode, Bid_CN_COOH, indicate that the redox reaction (Dye* ➔ Dye⁺ + e⁻) is stronger and more spon than the adsorption reaction (Dye⁺ + TiO₂ [+e⁻] ➔ Dye@TiO₂) in the electron injection. In this way, the highest efficiency of NL6 and NL12 is a consequence of the more significant pro-aromatic characteristics and the more spontaneous redox process. Finally, these NL dyes are promising in the molecular engineering of D-A -π -A metal-free types dyes.     

Characterization of the end products of the hydrolysis of iron in aqueous solution

A characterization of the iron phases precipitated from aerated solutions of iron(II) sulfate heptahydrate was made using Mössbauer spectroscopy. The experimental conditions for the preparation of the samples were varied. The results are used to the further understanding of rust formation during atmospheric corrosion.     

Comparative study of 2‐amino and 3‐aminobenzoic acid copolymerization with aniline synthesis and copolymer properties

Polyanilines soluble in an aqueous basic medium were synthesised by copolymerization of aniline (ANI) with both 2 and 3‐aminobenzoic acids (ABA). Different composition copolymers were prepared by varying the ANI/ABA feed ratio. Poly(aniline‐co‐2‐aminobenzoic acid) (PANI2ABA) and poly(aniline‐co‐3‐aminobenzoic acid) (PANI3ABA) displayed differences in their properties, such as specific charge and fluorescence behavior because the reactivity of 2‐aminobenzoic (2ABA) and 3‐aminobenzoic (3ABA) acids are very different. The new materials were characterized by X‐ray photoelectron, Fourier transform infrared, and Raman spectroscopies. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 5587–5599, 2004     

Thermal oxidation of metallocene ethylene-1-olefin copolymer films during one year oven aging

Metallocene ethylene homopolymer, ethylene-1-hexene and ethylene-1-octadecene copolymer films were characterized and analysed during their aging in a forced draft oven at 60 °C and compared to commercial polymers (HDPE and LDPE). Each polymer is essentially different in its structure, and the variables used in the present study are comonomer size and content in the main linear backbone polymer. The polymers were characterized initially using GPC, DSC, FTIR, and tensile tests. Later, at different time intervals, samples were removed from the oven and characterized using FTIR and GPC in order to detect changes in chemical structure, size, and molecular weight distribution due to thermo-oxidative aging. At the end of aging, films were subjected to tensile tests to quantify the effect of time on their useful life. As a qualitative reference parameter, the carbonyl index, the ratio of the infrared absorbance of the CO stretching band at 1715 cm⁻¹ and the absorbance of a reference band at 718 cm⁻¹, was determined. Kinetic thermo-oxidation is related to comonomer size and content in the main backbone polymer. As comonomer size decreases or comonomer content increases, degradation rate increases. The scission factor (S) and carbonyl index (CI) graphs of each material show a slope increase which is related to the autocatalytic rate of oxidation.     

2,6-Bis[(o-hydroxy)phenyliminomethyl]-1-hydroxybenzene as a reagent for the selective spectrofluorimetric determination of aluminium

A spectrofluorimetric method for the determination of aluminium at ng/ml level has been developed. The method is based on the formation of a fluorescent 11 complex between Al(III) and 2,6-bis[(o-hydroxy)phenyliminomethyl]-1-hydroxybenzene at an apparent pH of 5.0 in an aqueous-ethanol medium (70% v/v ethanol). The influence of reaction variables is discussed. The range of concentration of the method is 1.0–10.0 ng/ml aluminium, the relative standard deviation 1.5% and the limit of detection 0.1 ng/ml. The advantages of the proposed method include high sensitivity and selectivity. The method has been applied to the determination of aluminium in natural waters.     

Determination of unsulphonated quinoline yellow in soft drinks by solid-phase spectrophotometry

A spectrophotometric method for determination of quinoline yellow spirit soluble (QYSS) in the presence of sulphonated quinoline yellow water soluble (QYWS) in soft drinks at trace levels is reported. The method is based on the fixation of QYSS on C-18 silica gel, followed by measurement of its absorbance at = 418 nm in the solid phase after being packed in a 1-mm cell. The applicable concentration range was 1.5–15.0 ng/ml, the detection limit 0.4ng/ml and the relative standard deviation 5.2%. The method was applied satisfactorily to the determination of this compound in samples of commercial soft drinks.     

Synergistic mechanical behaviour and improved processability of poly(ether imide) by blending with poly(trimethylene terephthalate)

Fully miscible poly(ether imide) (PEI)/poly(trimethylene terephthalate) (PTT) blends were obtained by melt mixing in an extruder followed by injection moulding. The viscosity of PEI, represented by the pressure at the extruder output, almost halved upon the addition of only 10% PTT, allowing the use of PEI in applications where either complex parts or thin sections must be moulded. The modulus of elasticity showed a synergistic behaviour which was absolute (modulus higher than that of any of the two components) in the blend with 10% PTT. This was attributed mainly to the decrease in specific volume upon blending. The additional absolute synergism in the yield stress of PEI‐rich blends and their ductile nature depict a set of properties that make these new materials attractive in a number of new applications. Copyright ­© 2003 John Wiley & Sons, Ltd.     

Density, Excess Volumes, and Partial Volumes of the Binary Systems of Dimethyl Sulfoxide + Ethyl Acrylate, Butyl Acrylate, Methyl Methacrylate, and Styrene at 298.15 K

Densities of the binary systems of dimethyl sulfoxide with ethyl acrylate, butyl acrylate, methyl methacrylate, and styrene have been measured as a function of the composition at 298.15 K and atmospheric pressure using an Anton Paar DMA 5000 oscillating U-tube densimeter. The calculated excess volumes were correlated with the Redlich–Kister equation and with a series of Legendre polynomials. The excess volumes are negative for the four binaries, probably as a result of the large dipole moment of DMSO, becoming smaller as the monomer becomes more branched or longer, and the dipole moment per monomer unit becomes larger.