Spray‐processable thiazolothiazole‐based copolymers with altered donor groups and their electrochromic properties

Two novel thiazolo[5,4‐d]thiazole containing donor–acceptor type alternating copolymers, poly[2‐(5‐(2‐decyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)thiophen‐2‐yl)‐5‐(thiophen‐2‐yl)thiazolo[5,4‐d]thiazole] (BTzTh) and poly[2‐(5‐(2‐decyl‐2H‐benzo[d][1,2,3]triazol‐4‐yl)furan‐2‐yl)‐5‐(furan‐2‐yl)thiazolo[5,4‐d]thiazole] (BTzFr) were synthesized by Stille coupling polymerization and their electrochemical and electrochromic properties were explored. Electrochemical activities of the spray‐casted polymer films were determined by cyclic voltammetry. To evaluate the effect of thiophene and furan moieties on the optical properties of the copolymers, spectroelectrochemistry studies were performed. To examine the switching abilities, copolymer films were subjected to a double potential step chronoamperometry in their local maximum absorptions. Both thiazolothiazole‐containing copolymers showed multichromic properties with low band‐gap values 1.7 and 1.9 eV for BTzTh and BTzFr, respectively. The decent electrochromical properties together with solution processability make them important candidates for electrochromic applications. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3901–3906     

Electrochemical Determination of Cu(II) Ions by 4‐Formylphenylboronic Acid Modified Gold Electrode

A self‐assembled monolayer (SAM) modified by 4‐formylphenylboronic acid was formed on the gold electrode, which was applied for the determination of trace concentrations of Cu(II). The formation of advanced SAM on the gold electrode was evidenced by electrochemical impedance spectroscopy, atomic force microscopy and contact angle measurements. Electrochemical determination of Cu(II) ions was performed by square wave voltammetry. Some mutual interferences caused by Cd(II), Co(II), Fe(II), Ni(II) and Pb(II) ions were investigated and it was demonstrated how the negative effects of these interfering ions could be eliminated by adjustment of proper parameters of square wave voltammetry.     

Synthesis of new iron–NHC complexes as catalysts for hydrosilylation reactions

A series of new piano‐stool iron(II) complexes comprising N‐heterocyclic carbene ligands [Fe(Cp)(CO)₂(NHC)]I (NHC = 1,3‐disubstituted imidazolidin‐2‐ylidene) have been synthesized and analyzed by ¹H NMR, ¹³C NMR, IR, elemental analysis and mass spectrometric techniques. These compounds were easily prepared from the reaction of disubstituted imidazolidin‐2‐ylidene with [FeI(Cp)(CO)₂] in toluene at room temperature. These complexes were tested in the catalytic hydrosilylation reaction of aldehydes and ketones with phenylsilane in solvent‐free conditions. After a basic hydrolysis step, the corresponding alcohols were obtained in good yields. Copyright © 2013 John Wiley & Sons, Ltd.     

Crystal Structure of 4-Amino-3-(thiophen-2-ylmethyl)-1H-1,2,4-triazole-5(4H)one Monohydrate

The molecular structure of the 4-amino-3-(thiophen-2-ylmethyl)-1H-1,2,4-triazole-5(4H)one monohydrate was determined by X-ray diffraction. The compound crystallizes in the monoclinic sp. gr. C2/c with Z = 4 in the unit cell. The title compound is not planar. The dihedral angle between the thiophene and 1,2,4-triazole rings is 73.4(5)°. In the crystal structure, the molecules are connected by intermolecular N–H···O, N–H···N, O–H···O, and C–H···N type hydrogen bonds. The N–H···N and C–H···N hydrogen bonds link the molecules into infinite chains along the c axis.     

Codes over an infinite family of rings with a Gray map

Codes over an infinite family of rings which are an extension of the binary field are defined. Two Gray maps to the binary field are attached and are shown to be conjugate. Euclidean and Hermitian self-dual codes are related to binary self-dual and formally self-dual codes, giving a construction of formally self-dual codes from a collection of arbitrary binary codes. We relate codes over these rings to complex lattices. A Singleton bound is proved for these codes with respect to the Lee weight. The structure of cyclic codes and their Gray image is studied. Infinite families of self-dual and formally self-dual quasi-cyclic codes are constructed from these codes.     

Phosphorus-Nitrogen Compounds: Part 25. Syntheses,Spectroscopic, Structural and Electrochemical Investigations,Antimicrobial Activities,and DNA Interactions of Ferrocenyldiaminocyclotriphosphazenes

Abstract

The condensation reactions of hexachlorocyclotriphosphazene (N₃P₃Cl₆) with mono (1 and 2) and bisferrocenyldiamines (3–5 and 7) resulted in the formation of tetrachloro mono- (8 and 9) and bisferrocenylspirocyclotriphosphazenes (10–13). In addition the tetramorpholino mono- (8a and 9a) and bisferrocenylphosphazenes (10a–12a) were obtained from the reactions of the corresponding tetrachlorophosphazenes (8–12) with excess morpholine. The structures of all the phosphazenes were determined using FTIR, MS, ¹H, ¹³C, and ³¹P NMR and 2-dimensional NMR techniques. The structures of 9a and 13 were determined by single crystal X-ray diffraction techniques. Cyclic voltammetric investigations of compounds 8a, 9a, and 11a revealed that ferrocene redox centers undergo reversible oxidation. These ferrocenylphosphazenes appear to be quite robust electrochemically. Interactions between the compounds 8a, 9a, 11a, and 12a and pBR322 plasmid DNA were investigated by agarose gel electrophoresis.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfer, and Silicon and the Related Elements for the following free supplemental files: Additional text and figures.]     

Biofuel Cell Based on Anode and Cathode Modified by Glucose Oxidase

A single compartment biofuel cell (BFC) based on an anode and a cathode powered by the same fuel glucose is reported. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose consuming biocatalyst for both anode and cathode of the BFC. The 5‐amino‐1,10‐phenanthroline modified graphite rod electrode (GRE) with cross‐linked GOx was used as the bioanode, and the GRE with co‐immobilised horseradish peroxidase and GOx was exploited as the biocathode of the BFC. The open‐circuit voltage of the designed BFC exceeded 450 mV and a maximal power density of 3.5 µW/cm² was registered at a cell voltage of 300 mV.     

Ionic Liquid Modified Single‐use Electrode Developed for Voltammetric Detection of miRNA‐34a and its Application to Real Samples

The ionic liquid (IL) modified chemically activated (CA) pencil graphite electrodes (PGEs) were developed for label‐free voltammetric detection of miRNA‐34a, and implemented to the real samples. Firstly, the electrochemical characterization of unmodified PGE, CA‐PGE, IL‐PGE and IL‐CA‐PGE was performed by cyclic voltammetry (CV) as well as their DNA binding capacity was studied by electrochemical impedance spectroscopy (EIS) technique. The microscopic characterization of the surface of each electrodes was investigated by scanning electron microscopy (SEM). Differential pulse voltammetry (DPV) technique was used for measuring the oxidation signal of guanine in order to perform a label‐free voltammetric monitoring of a full‐match hybridization specific to miRNA‐34a. The selectivity of biosensor was tested against to miRNA‐155, miRNA‐660 as well as to the mismatch sequence of miRNA‐34a. The further selectivity of this proposed biosensor was studied in the mixture of samples containing miRNA‐34a with other miRNAs (1 : 1). The voltammetric detection of miRNA‐34a was also explored in the artificial serum medium as fetal bovine serum (FBS) and also in total RNA samples isolated from HUH‐7 human hepatocellular carcinoma cell line.     

Low-Dimensional Description of Oscillatory Thermal Convection: The Small Prandtl Number Limit

 Low-dimensional models are derived for transitional, buoyancy-driven flow in a vertical channel with prescribed spatially periodic heating. Stationary characteristic structures (empirical eigenfunctions) are identified by applying proper orthogonal decomposition to numerical solutions of the governing partial differential equations. A Galerkin procedure is then employed to obtain suitable low-order dynamical models. Stability analysis of the fixed points of the low-order systems predicts conditions at the primary flow instability that are in very good agreement with direct numerical solutions of the full model. This agreement is found to hold as long as the low-order system possesses a possible Hopf bifurcation (minimum two-equation) mechanism. The effect of the number of retained eigenmodes on amplitude predictions is examined. Received 25 January 1996 accepted 19 July 1996