Incorporation of fused tetrathiafulvalenes (TTFs) into polythiophene architectures: varying the electroactive dominance of the TTF species in hybrid systems

A novel polythienylenevinylene (PTV) and two new polythiophenes (PTs), featuring fused tetrathiafulvalene (TTF) units, have been prepared and characterized by ultraviolet-visible (UV-vis) and electron paramagnetic resonance (EPR) spectroelectrochemistry. All polymers undergo two sequential, reversible oxidation processes in solution. Structures in which the TTF species is directly linked to the polymer backbone (2 and 4) display redox behavior which is dictated by the fulvalene system. Once the TTF is spatially removed from the polymer chain by a nonconjugated link (polymer 3), the electroactivity of both TTF and polythiophene moieties can be detected. Computational studies confirm the delocalization of charge over both electroactive centers (TTF and PT) and the existence of a triplet dication intermediate. PTV 4 has a low band gap (1.44 eV), is soluble in common organic solvents, and is stable under ambient conditions. Organic solar cells of polymer 4:[6,6]-phenyl-C(61) butyric acid methyl ester (PCBM) have been fabricated. Under illumination, a photovoltaic effect is observed with a power conversion efficiency of 0.13% under AM1.5 solar simulated light. The onset of photocurrent at 850 nm is consistent with the onset of the pi-pi absorption band of the polymer. Remarkably, UV-vis spectroelectrochemistry of polymer 4 reveals that the conjugated polymer chain remains unchanged during the oxidation of the polymer.     

Piano‐stool Ru (II) arene complexes that contain ethylenediamine and application in alpha‐alkylation reaction of ketones with alcohols

A series of piano‐stool Ru (II) complexes ( Ru _1–7 ) bearing ethylenediamine with aryl and aliphatic groups were prepared and fully characterized by ¹H, ¹³C, ¹⁹F and ³¹P NMR spectroscopy, FT‐IR and elemental analysis. The crystal structures of Ru _2–4 and Ru ₇ were determined by X‐ray crystallography. They were successfully applied to the alpha(α)‐alkylation of aliphatic and aromatic ketones with alcohols via the borrowing hydrogen strategy in mild reaction conditions within a short time. The catalytic system has a broad substrate scope, which allows the synthesis of alpha alkylated ketones with excellent yields. The electronic and steric effects of complexes on catalytic activity were analysed. The influence of the carbon chain length of the ligand on the alpha‐alkylation reaction of ketones was also investigated. The catalytic cycle was also examined by ¹H‐NMR spectroscopy in d₈‐toluene.     

Anodic stripping voltammetric determination of vardenafil hydrochloride at pencil graphite electrode

In this paper, we present a very popular and low-cost sensor material as disposable pencil graphite electrode (PGE) system for the trace-level determination of vardenafil hydrochloride (VRL). Electrochemical behavior and determination of VRL was carried out by cyclic and square-wave adsorptive anodic stripping (SW-AdAS) voltammetry. The proposed method was highly sensitive and had a linear calibration range from 3 × 10^?10 to 1 × 10^?7 M with a correlation coefficient of 0.997. The limit of detection and limit of quantitation values were calculated as 1 × 10^?10 and 3 × 10^?10 M, respectively. Developed method with disposable PGE shows high sensitivity, selectivity and stability in a wide concentration range for VRL determination without the necessity of any modification. Additionally, this system was successfully applied in Levitra^® tablets and spiked human serum in trace level of VRL. Some kinetic parameters of VRL’s were represented for the first time. The results showed that the proposed method is highly sensitive, easy and low cost for trace-level determination of VRL.     

Determination of Minimum Enzymatic Decolorization Time of Reactive Dye Solution by Spectroscopic & Mathematical Approach

Synthetic dyes are very important for textile dyeing,paper printing,color photography and petroleum products.Traditional methods of dye removal include biodegradation,precipitation,adsorption,chemical degradation,photo degradation,and chemical coagulation.Dye decolorization with enzymatic reaction is an important issue for several research field(chemistry,environment)In this study,minimum decolorization time of Remazol Brilliant Blue R dye with Horseradish peroxidase enzyme was calculated using with mathematical equation depending on experimental data.Dye decolorization was determined by monitoring the absorbance decrease at the specific maximum wavelength for dye.All experiments were carried out with different initial dye concentrations of Remazol Brilliant Blue R at 25 ℃ constant temperature for 30 minutes.The development of the least squares estimators for a nonlinear model brings about complications not encountered in the case of the linear model.Decolorization times for completely removal of dye were calculated according to equation.It was shown that mathematical equation was conformed exponential curve for dye degradation.     

Synthesis of asymmetrical tridendate Schiff bases and metal complexes and investigation of anticarcinogen effects on human colon and cervical cancers

The metal complexes of Zn(II), Ni(II), Cu(II) and Pb(II) with asymmetrical Schiff bases were synthesized. The asymmetrical Schiff base was obtained through the condensation of 1,2-phenylenediamine, 4-methyl-1,2-phenylenediamine, 2-hydroxy-1-napthaldehyde and biphenyl-4-carbaldehyde. The new Schiff base ligands (L₁' and L₂') and their metal complexes were characterized by TG/DTG, FT-IR, ¹H-NMR, UV–Vis, ESR, powder XRD, elemental analysis, magnetic moment and fluorescence studies. The powder XRD studies indicate that Co(II) and Cu(II) complexes are amorphous, while Ni(II) and Zn(II) complexes are crystalline. The anticarcinogenic effects of L₁' and L₂' were also investigated against colon (SW-620) and cervical cancer (HeLa) cell lines and compound L₂' was found to possess the highest anticarcinogenic potential, with 16.7 µM and 27.5 µM of IC₅₀ values for HeLa and SW620 cells, respectively.     

Enhanced reactivity in a heterogeneous oxido-peroxido molybdenum(VI) complex of salicylidene 2-picoloyl hydrazone in catalytic epoxidation of olefins

A molybdenum(VI) oxido-diperoxido complex of salicylidene 2-picoloyl hydrazine (sal-phz) was synthesized and successfully grafted onto chloro-functionalised Fe₃O₄ nanoparticles. The resulting heterogeneous and magnetically recoverable nanoscale catalyst MoO₃(sal-phz)/Fe₃O₄ was characterized by physicochemical and spectroscopic techniques. The activity of this heterogeneous catalyst for the oxidation of olefins to corresponding epoxides was efficiently increased by increasing the reaction temperature up to 95 °C. The nanocatalyst proved to be efficient for the selective epoxidation of a variety of alkenes using t-BuOOH with high conversion and selectivity. Leaching and recycling tests showed that the nanocatalyst can be reused at least six times without significant decrease in efficiency.     

Enzymatic Decolorization of Anthraquinone and Diazo Dyes Using Horseradish Peroxidase Enzyme Immobilized onto Various Polysulfone Supports

In this study, covalent immobilization of the horseradish peroxidase (HRP) onto various polysulfone supports was investigated. For this purpose, different polysulfones were methacrylated with methacryloyl chloride, and then, nonwoven fabric samples were coated by using solutions of these methacrylated polysulfones. Finally, support materials were immersed into aquatic solution of HRP enzyme for covalent immobilization. Structural analysis of enzyme immobilization onto various polysulfones was confirmed with Fourier transform infrared spectroscopy, atomic force microscopy, and proton nuclear magnetic resonance spectroscopy. Decolorization of textile diazo (Acid Black 1) and anthraquinone (Reactive Blue 19) dyes was investigated by UV–visible spectrophotometer. Covalently immobilized enzyme has been used seven times in freshly prepared dye solutions through 63 days. Dye decolorization performance of the immobilized systems was observed that still remained high (70 %) after reusing three times. Enzyme activities of immobilized systems were determined and compared to free enzyme activity at different conditions (pH, temperature, thermal stability, storage stability). Enzyme activities of immobilized systems and free enzyme were also investigated at the different temperatures and effects of temperature and thermal resistance for different incubation time at 50 °C. In addition, storage activity of free and immobilized enzymes was determined at 4 °C at different incubation days.     

Quantum chemical studies on prototautomerism of 1H‐imidazo[4,5‐c]pyridine

The structural features of the 1H‐imidazo[4,5‐c]pyridine (ICPY) tautomers and homodimers of the most stable tautomers have been studied by quantum chemical methods. FTIR and Raman spectra of the ICPY were recorded in the range of 4000–60 cm^?1 and 3500–5 cm^?1. The predominant tautomer among four possible isomers of ICPY were determined. The optimized geometries and vibrational frequencies of possible ICPY tautomers and dimers were computed by B3LYP/DFT method with 6‐311++G(d,p) and 6‐31G(d) basis sets. All vibrational frequencies assigned in detail with the help of total energy distribution (TED) and isotopic shifts. ICPY dimeric forms were also characterized according to their hydrogen bonding interactions, and it has been found that the most stable ICPY homodimer establishes moderate strong N ? H …N type hydrogen bond. ¹H NMR, ¹³C NMR, and ¹⁵N NMR properties have been calculated for all tautomeric forms using the gauge independent atomic orbital (GIAO) method. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011