Synthesis, characterization and nonlinear absorption of novel octakis-POSS substituted metallophthalocyanines and strong optical limiting property of CuPc

In this study, the preparation of some novel metallophthalocyanine (MPcs) complexes substituted with octakis(mercaptopropylisobutyl-POSS) functional group was achieved. By the reaction of [1-(3-mercapto)propyl-3,5,7,9,11,13,15-isobutylpentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane 1 with 4,5-dichloro-1,2-dicyanobenzene 2 in THF as the solvent in the presence of K2CO3 as the base, the phthalonitrile derivative 3 was synthesized. Compound 3 reacted with CoCl2 x 6H2O in ethylene glycol to furnish a novel cobalt(II) phthalocyanine . The tetramerization of 3 with urea and CuCl in the absence of solvent gave the novel Cu(II) phthalocyanine 4; while with Zn(OAc)2 x 2H2O in dry DMF gave the novel zinc(ii) phthalocyanine 6. The structures of the target compounds were confirmed by elemental analysis, UV/VIS, IR, MALDI-TOF MS and 1H NMR spectra. Nonlinear absorptions of MPcs in chloroform solution were investigated by using Z-scan measurement technique with 4 ns pulses at 532 nm wavelength. While CuPc 5 showed very high nonlinear absorption, MPcs 4 and 6 did not show considerable nonlinear absorption. Investigations of optical limiting properties of 5 revealed that this material is a very good candidate for optical limiting applications.     

Folic‐Acid‐Modified Conducting Polymer: Electrochemical Detection of the Cell Attachment

Here, postfunctionalization and bioapplication of a π‐conjugated polymer named 4‐[4H‐dithieno(3,2‐b:2′,3′‐d)pyrrol‐4‐yl]aniline (DTP‐aryl‐NH₂) are reported, which is successfully synthesized via electropolymerization onto the glassy carbon electrode. Folic acid (FA) is used to modify the amino functional polymer via N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride/N‐hydroxysuccinimide chemistry for the further steps. The selective adhesion of folate receptor positive cells on the surface is followed by the electrochemical methods. Cyclic voltammetry and electrochemical impedance spectroscopy have been used to characterize stepwise modification of the electroactive surface. After optimization studies such as scan rate during the polymer deposition, FA amount for the efficient surface targeting, incubation time with the cells etc., analytical characterization is carried out. The surface morphologies at each step are imaged by using fluorescence microscopy.

     

Synthesis, characterization and electrical properties of novel mono- and cofacial bisphthalocyanines bridged with four [1a,8b-dihydronaphtho[b]naphthofuro[3,2-d]furan-7,10-diyl] units

Novel mono phthalocyanines and cofacial bisphthalocyanines were synthesized from 4,4′-(1a,8b-dihydronaphtho[b]naphthofuro-[3,2-d]furan-7,10-diyl)bis(oxy)diphthalonitrile 1. The products were characterized by elemental analysis, UV-vis, IR, ¹H NMR and mass spectroscopy. Both the direct current (dc) and alternating current (ac) electrical properties of the product films were investigated as a function of temperature in the frequency range 40-10⁵ Hz. It was observed that the ac response of the films can be represented by the ω^s law. The temperature dependence of dc conductivity showed typical Arrhenius behavior for all compounds.     

Synthesis, characterization and chromotropic properties of MnII, CoII, NiII and CuII with bis (acesulfamato) bis ( 3 -methylpyridine) complexes

The novel 3- [M: Mn^II, Co^II, and Ni^II] and 3- complexes (acs: acesulfamate; 3-pic: 3-methylpyridine) have been synthesized and characterized using elemental analyses, magnetic moments, UV–Vis and FT-IR spectra. The thermal behaviour of the complexes was also studied by simultaneous TG, DTG and DTA methods in static air atmosphere. The chromotropic properties of all complexes have been studied using thermal and spectral analysis. While the complexes of Co^II and Ni^II show reversible continuous thermochromism, an irreversible discontinuous thermochromism is observed in the Mn^II and Cu^II) complexes in the solid state. The observed thermochromism in the Mn^II, Co^II and Ni^II complexes is due to the different ligand field strength associated with the deaquation reaction. The solvatochromic behaviour of the complexes is also studied and all anhydrous complexes (except Mn^II) exhibit solvatochromic properties depending on the donor number of the solvent.     

Matrix elimination method for the determination of precious metals in ores using electrothermal atomic absorption spectrometry

Poly(N-(hydroxymethyl)methacrylamide)-1-allyl-2-thiourea) hydrogels, poly(NHMMA-ATU), were synthesized by gamma radiation using ⁶⁰Co γ source in the ternary mixture of NHMMA-ATU-H₂O. These hydrogels were used for the specific gold, silver, platinum and palladium recovery, pre-concentration and matrix elimination from the solutions containing trace amounts of precious metal ions. Elimination of inorganic matrices such as different transition and heavy metal ions, and anions was performed by adjusting the solution pH to 0.5 that was the selective adsorption pH of the precious metal ions. Desorption of the precious metal ions was performed by using 0.8 M thiourea in 3 M HCl as the most efficient desorbing agent with recovery values more than 95%. In the desorption medium, thiourea effect on the atomic signal was eliminated by selecting proper pyrolysis and atomization temperatures for all precious metal ions. Precision and the accuracy of the results were improved in the graphite furnace-atomic absorption spectrometer (GFAAS) measurements by applying the developed matrix elimination method performing the adsorption at pH 0.5. Pre-concentration factors of the studied precious metal ions were found to be at least 1000-fold. Detection limits of the precious metal ions were found to be less than 10 ng L⁻¹ of the all studied precious metal ions by using the proposed pre-concentration method. Determination of trace levels of the precious metals in the sea-water, anode slime, geological samples and photographic fixer solutions were performed using GFAAS clearly after applying the adsorption-desorption cycle onto the poly(NHMMA-UTU) hydrogels.     

Structural characterization of <Emphasis Type="Italic">N</Emphasis>,<Emphasis Type="Italic">N</Emphasis>′-bis(2-methoxyethyl) -4,5-bis(2,4,6-trimethylphenyl)imidazolinium hexafluorophosphate

The crystal and molecular structure of the N,N′-bis(2-methoxyethyl)-4,5-bis(2,4,6-trimethylphenyl)- imidazolinium hexafluorophosphate, which is the first example of 1,3- and 4,5-disubstituted imidazolinium salts, have been determined and characterized by X-ray single crystal diffraction technique,¹H, ¹³C, ³¹P and ¹⁹F NMR spectroscopy. The compound, C₂₇H₃₉N₂O₂ ⁺·PF₆ ^?, crystallizes in the orthorhombic space group Pba2 with a = 15.8139(4) Å, b = 22.9346(7) Å, c = 8.069(3) Å. Two charge-assisted C–H\(\cdots\)F type crystal packing interactions between the imidazolinium C–H bonds and the F atoms of hexafluorophosphate counteranions build up zigzag chains along a-axis of the unit cell and indicate that the C–H bonds of the imidazolinium ring are also polarized. In addition, the title salt was modeled by DFT calculations in order to verify charge transfer mechanism observed in its imidazolinium ring.     

Thermo-economic optimization of a hybrid photovoltaic and thermoelectric power generator using overall performance index

A thermo-economic assessment of a hybrid concentrated photovoltaic–thermoelectric power generator (CPV–TEG) is performed based on the first law of thermodynamics and principles of costing. This study aims at estimating the optimum water-cooled CPV–TEG design parameters that yield the maximum overall performance. The influence of key parameters (such as direct normal irradiance (DNI), geometric concentration, thermoelectric figure of merit, temperature ratio of thermoelectric junction and heat sink thermal resistance) and their significance on the performance and cost of the system is examined. A performance measure known as the overall performance index (OPI) is used to evaluate the optimum design of the CPV–TEG system operating within the limits of allowable cell temperatures. OPI can incorporate several performance indicators that are crucial for performance estimation of a hybrid system by using a mass coefficient for each indicator based on its priority in the overall system performance. OPI accounts for three performance indicators of the CPV–TEG system, namely: energy efficiency, cost of the solar receiver (COSR) and levelized cost of energy (LCOE). The variation of the OPI provides an indication of the performance of the hybrid system under different design parameters and the selection of the appropriate design of the system to be at a point where the OPI is a maximum. Two scenarios are considered such that different mass coefficients are assigned to the performance indicators when evaluating the system performance. In the first scenario (performance case), energy efficiency is given the highest priority while for the second scenario (economic case), the cost of the solar receiver (CPV–TEG system) is given more emphasis. Optimization is performed for the water-cooled CPV–TEG design such that the PV temperature is kept below the maximum allowable cell temperature of 100 °C. LCOE of 0.0392 $ kWh^?1 was obtained with an optimum OPI of 94.7% for the economic case.

     

Synthesis and characterization of folic acid-chitosan nanoparticles loaded with thymoquinone to target ovarian cancer cells

The aim of the present research was to formulate and characterize radioiodinated folic acid-chitosan conjugated thymoquinone nanoparticles (FATQCSNPs) and to increase targeting ability on ovarian cancer cell. The dose of drug-loading into the FATQCSNPs and the amount of folic acid on the FATQCSNPs surface were determined as a 20.0?±?1% and 46.0?±?0.5%, respectively. Cell viabilities (%) determined on SKOV-3 and Caco-2 cells for 48 h. TQ, TQCS and FATQCS were very cytotoxic with lower IC₅₀ values on both cell lines. At specific-activity-dependent incorporation study, the incorporation efficiencies of ¹³¹I-FATQCSNPs was higher than that of ¹³¹I-TQ on SKOV3 cell lines.

     

Rational Chebyshev collocation method for solving higher‐order linear ordinary differential equations

A collocation method to find an approximate solution of higher‐order linear ordinary differential equation with variable coefficients under the mixed conditions is proposed. This method is based on the rational Chebyshev (RC) Tau method and Taylor‐Chebyshev collocation methods. The solution is obtained in terms of RC functions. Also, illustrative examples are included to demonstrate the validity and applicability of the technique, and performed on the computer using a program written in maple9. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 27: 1130–1142, 2011