M. Levent Aksu

Thermal characterization and theoretical and experimental comparison of picryl chloride derivatives of heterocyclic energetic compounds

There were 10 nitrogen-rich energetic compounds prepared by the reaction of 2,4,6-trinitrochlorobenzen (picryl chloride) with pyrazole, 1,2,4-triazole, imidazole, 3-aminopyrazole, 3-nitropyrazole, 3-amino-1,2,4-triazole, 3-nitro-1,2,4-triazole, 3,5-diamino-1,2,4-triazole and guanidine. These compounds were characterized with IR spectra, elemental analysis and 1H NMR and 13C NMR methods. They were also examined with thermogravimetry and differential thermal analyses. The heat generated after the explosion was measured by the use of differential scanning calorimetry. The formation enthalpies of some of the products synthesized were determined by the use of Gaussian 09 software, and probable products were estimated from the data reported in the literature. Finally, theoretical explosion energies of these compounds were calculated using the theoretical formation enthalpies and compared with experimental data.

Crystal structure of a new homo trinuclear Ni(II) complex with μ-cyanoacetato bridge

Abstract Ni(II)-Ni(II)-Ni(II) homo-trinuclear linear complex was prepared using bis-N,N′(2-hydroxybenzyl)-1,3-propanediamine in DMF (dimethyl formamide) medium. μ-bridges between metal nuclei are formed using formate, acetate, chloroacetate and benzoate ions. The structure of the homo-trinuclear complex was determined with X-ray diffraction method. It was found that the terminal Ni(II) ions have a N2O4 coordination sphere and central Ni(II) ion has a O6 octahedral coordination sphere. The chelate ring, formed by the coordination of terminal Ni atoms and aminic nitrogen atoms, was found to have a chair conformation. The complexes were elucidated by the use of thermogravimetry and differential thermal analysis method. In acetate, chloroacetate, cyanoacetate and benzoate containing complexes thermal dissociation of DMF took place first while in formate containing complex it was observed that formate bridges and the complex degraded together with the dissociation of DMF moiety. It was observed that the thermal stability of carboxylate μ-bridge affects the thermal stability of the homo-nuclear complex. The average bond energies of coordinated DMF molecules were determined and these coordinative bond energies were found to be in the dimension of that of hydrogen bonds.

Fabrication and Characterization of Boron Doped Ni/Zn Acetate Nanofibers

This study is related to the preparation of boron doped Nickel/Zinc metal fibers prepared by the use of electrospinning technique. The originality of this study is the addition of boron to metal acetates. The addition of boron did not only increase the thermal stability of the fibers, but also increased their diameters, which gave stronger fibers. The FT-IR spectra of the fibers were in good accordance with literature. The differential scanning calorimetry (DSC) results indicate that the glass transition (Tg) and melting temperatures (Tm) showed great change with the addition of boron and boron doped fibers were observed to degrade at higher temperatures. The SEM appearance of the fibers showed that the addition of boron resulted in the formation of cross linked bright surfaced fibers.

A novel and highly sensitive electrochemical sensor based on a high-quality modified graphene electrode for the determination of hydrochlorothiazide in pharmaceutical formulations and human plasma

This study is concerned with the development of a practical, efficient and highly sensitive electrochemical sensor for the determination of hydrochlorothiazide (HCT) in pharmaceutical dosage forms or clinical samples using a high-quality modified graphene electrode (H-GRE) which has recently emerged as a very promising material for sensor applications. High-quality graphene (H-GR) was synthesized efficiently by a single-step reduction method from graphene oxide (GO). It was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and transmission electron spectroscopy (TEM). The electrochemical behavior of HCT was investigated using adsorptive stripping differential pulse voltammetry on the H-GRE. The H-GRE showed excellent electrochemical activity for the oxidation of HCT. Under the optimized experimental conditions, the linear response range of HCT was found to be 0.1–48.0 μM with a detection limit (based on S/N = 3) of 19 nM. This improved electrode may provide a promising alternative sensor for the determination of HCT in pharmaceutical formulations and clinical samples.

Electrochemical Investigation of Zinc(II)-Furdap Amide Complex in DMSO Medium

The electrochemical behavior of Zinc(II)-furdap amide complex has been investigated by the use of several electrochemical methods in DMSO on platinum electrode. Both the ligand and the complex gave one electron transfer re- duction. Although there was no oxidation peak observed corresponding to the reduction of ligand, there was a correspond- ing oxidation peak appeared for the complex. The number of electrons transferred was calculated as 1 by the use of bulk electrolysis, rotating disc electrodes employing Kouteck� -Levich equation. The reversibility tests revealed that the reac- tion followed a quasi reversible mechanism. The mechanism was also confirmed by simulation studies. ks and  values were found to be 1.0 10 -7 cm s -1 and 0.4, respectively. The diffusion coefficient (D) was found as 6.93  10 -5 cm 2 s -1 by the use of Cottrell slope obtained from chronoamperometry experiments and ultra micro disc steady state current (iss).