Cobalt,Nickel and Copper Complexes of Benzylamino-p-chlorophenylglyoxime. Thermal and thermodynamic data

Vic-dioxime ligandsand their metal complexes are used in analytical, bio, pigment and medicinal chemistry. Complexes of nickel(II), copper(II), and cobalt(II) with benzylamino-p-chlorophenylglyoxime (BpCPG) are synthesised. Thermal behaviour of these complexes was studied in dynamic nitrogen atmosphere by DTA, DTG and TG techniques. GC-MS combined system was used to identify the products during pyrolytic decomposition. The pyrolytic end products were identified by X-ray powder diffraction. Thermoanalytical data of these complexes are presented in this communication. Interpretation and mathematical analysis of these data and evaluation of order of reaction, the energy and entropy of activation based on the integral method using the Coats-Redfern equation and the approximation method using the Horowitz-Metzger equation are also given. The metal complexes undergo decomposition in three stages and metal oxides remained as end products of the complexes. This revised version was published online in August 2006 with corrections to the Cover Date.     

Synthesis of oxime bearing cyclophosphazenes and their reactions with alkyl and acyl halides

Two novel cyclophosphazenes containing oxime groups were prepared from the hexakis(4‐formylphenoxy)cyclotriphosphazene ( 2 ) and hexakis‐(4‐acetylphenoxy)cyclotriphosphazene ( 7 ). The reactions of these oximes with acetyl chloride, chloroacetyl chloride, methyl iodide, propyl chloride, mono‐ chloroacetone, and 1,4‐dichlorobutane were studied. Hexasubstituted compounds were obtained from the reactions of hexakis(4‐[(hydroxyimino)methyl]phenoxy)cyclotriphosphazene ( 3 ) with acetyl chloride ( 4 ) and chloroacetyl chloride ( 5 ); however, tetrasubstituted product was obtained from methyl iodide ( 6 ). Tetra‐ and trisubstituted products were obtained from the reactions of hexakis(4‐[(1)‐N‐hydroxyethaneimidoyl]phenoxy)cyclotriphosphazene ( 8 ) with acetyl chloride ( 9 ) and chloroacetyl chloride ( 10 ), respectively. All products were obtained in high yields. Pure and defined product could not be obtained from the reaction of 8 with methyl iodide, and could not be also obtained from the reactions of 3 and 8 with propyl chloride, monochloroacetone, and 1,4‐dichlorobuthane. The structures of the compounds were defined by elemental analysis, IR, ¹H, ¹³C, and ³¹P NMR spectroscopy. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:112–117, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20176     

Effect of ball-milling conditions on microstructure during production of Fe–20Mn–6Si–9Cr shape memory alloy powders by mechanical alloying

Phase transitions associated with Fe?C20?wt% Mn?C6?wt% Si?C9?wt% Cr alloy during mechanical alloying and after subsequent annealing of that are studied experimentally. The conventional powder metallurgy route was used in preparing the sample. The milling time ranged from 5 to 20?h. Changes in microstructure as a function of milling time were investigated by using X-ray diffraction analysis, differential scanning calorimeter, and scanning electron microscopy. The grain sizes of powder milled are determined. The critical temperatures associated with the transformations are found to change with increasing ball-milling time.     

Upper and lower bounds on subcarrier collision for inter-cell interference scheduler in OFDMA-based systems: Voice traffic

This study investigates upper and lower bounds on subcarrier collision for inter-cell interference (ICI) schedulers in orthogonal frequency division multiple access (OFDMA)-based wireless systems carrying voice traffic. It is shown that the amount of knowledge regarding the reserved resources in the neighboring cell plays a crucial role in the performance of ICI schedulers. Also, it is proven that the upper bound of subcarrier collision for ICI schedulers corresponds to the case which is driven by the absence of knowledge about the reserved resources in the neighboring cell. On the other hand, the lower bound of subcarrier collision for ICI schedulers corresponds to the case which is driven by the perfect knowledge about the reserved resources in the neighboring cell. Based on the lower bound analysis, a minimum expected number of collision scheduler is developed and its performance is investigated as well. Moreover, the impact of scheduling period on the performance of schedulers is examined. Numerical results are presented along with related discussions.     

GC–MS Determination of Atenolol Plasma Concentration after Derivatization with N-methyl-N-(trimethylsilyl)trifluoroacetamide

An analytical procedure was developed and validated for the determination of atenolol in human plasma. Atenolol and metoprolol (internal standard) were extracted from human plasma with a mixture of chloroform and butanol at basic pH. The extracts were derivatized with N-methyl-N-(trimethylsilyl)trifluoroacetamide and analyzed by GC–MS. Calibration curves were linear over the concentration range 15–250 ng mL^?1. Intra- and inter-day precision values for atenolol in human plasma were less than 7.4, and accuracy (relative error) was better than 6.4%. Recovery of atenolol from human plasma averaged 90.46%. The limits of detection (LOD) and quantitation (LOQ) of atenolol were 5.0 and 15 ng mL^?1. This method was successfully applied to six patients with hypertension who had been given an oral tablet of 50 mg atenolol.     

Ceramide and Cerebroside from the stem bark of Ficus mucuso (Moraceae)

Two new sphingolipids mucusamide (1) and mucusoside (2) have been isolated from methanol soluble part of the stem bark of Ficus mucuso WELW., together with fifteen known secondary metabolites including cellobiosylsterol (3), β-sitosterol (4), stigmasterol (5), β-sitosterol 3-O-β-D-glucopyranoside (6), lupeol acetate (7), ursolic acid (8), procatechuic acid (9), 2-methyl-5,7-dihydroxychromone 8-C-β-D-glucoside (10), apigenin (11), (-)-epicatechin (12), (+)-catechin (13), N-benzoyl-L-phenylalanilol (14), α-acetylamino-phenylpropyl α-benzoylamino-phenylpropionate (15), asperphenamate (16) and bejaminamide (17). Structures of compounds 1 and 2 were elucidated by spectroscopic analysis and chemical methods.     

Multi-colored electrochromic polymer with enhanced optical contrast

A new π-conjugated monomer was synthesized which contains an electron-donating unit 3,4-ethylenedioxythiophene and electron withdrawing quinoxaline-based heterocycle to examine the effects of imine unit on the optoelectronic and redox properties of the resulting polymer. Electroactivity of monomer and electrochemical redox behavior of its polymer were investigated by cyclic voltammetry. An irreversible anodic wave at +0.85 V vs Ag wire reference electrode corresponding to the monomer oxidation was observed. Spectroelectrochemical analysis revealed that the neutral polymer has an absorbance at 820 nm. The band gap of the polymer was determined as 1.0 eV from the onset of the π-π∗ transition. The polymer shows multi-colored electrochromic behavior with five distinct states: brick red (−0.3 V), orange (+0.4 V), brown (+0.7 V), green (+0.85 V), gray (+1.2 V). The polymer revealed 34% optical contrast at 460 nm and an excellent optical contrast of 99% in the NIR region.     

Magnetic nanocomposite spinel and FeCo core-shell and mesoporous systems

The fabrication of condensed silica and mesoporous silica coated spinel CoFe₂O₄ and FeCo alloy magnetic nanocomposites are reported. The encapsulation of well-defined 5 nm thick uniform silica layer on CoFe₂O₄ magnetic nanoparticles was performed. The formation of mesopores in the shell was a consequence of removal of organic group of the precursor through annealing. The NiO nanoparticles were loaded into the mesoporous silica. The mesoporous silica shells leads to a larger coercivity than that of pure CoFe₂O₄ magnetic nanoparticles due to the decrease of interparticle interactions and magneto-elastic anisotropy. In addition, the FeCo nanoparticles were coated by condensed and mesoporous silica. The condensed silica can protect the reactive FeCo alloy from oxidation up to 300 °C. However, saturation magnetization of FeCo nanoparticles coated by silica after 400 °C annealing is dramatically decreased due to the oxidation of the FeCo core. The mesoporous silica coated magnetic nanostructure loaded with NiO as a final product could be used in the field of biomedical applications.     

Normal coordinate analysis and crystal structure of N,N-dimethyl-N'-(2-chloro-benzoyl)thiourea

In the present paper, the crystal structural and vibrational analysis of the N,N-dimethyl-N'-(2-chloro-benzoyl)thiourea molecule is reported. The molecular structure of the title compound was determined by single crystal X-ray diffraction method. The compound crystallizes monoclinic, space group P2(1)/c with a=5.6601(13)A, b=10.748(2)A, c=17.778(4)A, beta=94.266(5) degrees , and V=1078.5(4)A(3) with Z=4 for d(calc)=1.495 g/cm(3). Calculations of the vibrational frequencies have been carried out on the basis of normal coordinate analysis using simple general valence force field in Wilson's GF matrix method with the SPSIM computer program. With the help of this modern technique we were able to complete the assignment of the vibrational spectrum of the title compound.     

Thermal Decomposition Kinetics of Some Metal Complexes of N,N-diethyl-n '-benzoylthiourea

Thermogravimetry (TG) and differential thermal analysis (DTA) were performed on the complexes with general formula (M(DEBT)_n (where M =Fe, Co, Ni, Cu or Ru; n =2, or 3 and DEBT=N,N-diethyl-N'-benzoylthiourea). Derivative thermogravimetric (DTG) curves were also recorded in order to obtain decomposition data on the complexes. The complexes of Fe(III), Co(II), Ni(II), Cu(II) and Ru(III) displayed two- or three-stage decomposition patterns when heated in a dynamic nitrogen atmosphere. Mass loss considerations relating to the decomposition stages indicated the conversion of the complexes to the sulfides or to the corresponding metal alone (Cu, Ru, NiS, CoS or FeS). Mathematical analysis of the TG and DTG data showed that the order of reaction varied between 0.395 and 0.973. Kinetic parameters such as the decomposition energy, the entropy of activation and the pre-exponential factor are reported. This revised version was published online in July 2006 with corrections to the Cover Date.