Bulent Caglar

Structural Characterization of Aniline-Bentonite Composite by FTIR, DTA/TG, and PXRD Analyses and BET Measurement

ABSTRACT The aniline species incorporated into the acid-activated bentonite matrices leads to the decay of the skeletal stretches centered at 1041 cm−1 and the rise of new features in the phenyl ring frequency region, 1700–1400 cm−1, demonstrates clearly the influence of the acid activation on the Lewis sites necessary for coordination of aniline to bentonite. The exothermic DTA features at 507, 684, and 725°C indicate the release of both the clusters and the decomposed fragments of the aniline-clay composite, and the highly stable carbonaceous residue, respectively. The basal difference by ∼1.0 nm and the much smaller surface area (33.8 m2/g) than that of the nonintercalated bentonite (129.2 m2/g) prove the presence of the tilted aniline species between the interlamellar grooves of the bentonite framework.

New metal complexes with diclofenac containing 2-pyridineethanol or 2-pyridinepropanol: synthesis, structural, spectroscopic, thermal properties, catechol oxidase and carbonic anhydrase activities

Abstract Four new neutral diclofenac-based complexes, [Co(dicl)2(2-pyet)2] 1, [Ni(dicl)2(2-pyet)2] 2, [Cu2(dicl)2(2-pyet)2] 3, and [Cu2(dicl)2(2-pypr)2] 4 have been synthesized and characterized by elemental analysis, FT-IR, thermal analysis. Complexes 1, 3, and 4 have also been characterized by X-ray single-crystal structural analysis. The compounds of Co(II) and Ni(II) have octahedral geometry with two diclofenac and two 2-pyridineethanol ligands in the coordination sphere. The compounds of Cu(II) have square-pyramidal geometry and Cu(II) ions are linked via oxygens to the bridging 2-pyridineethanol or 2-pyridinepropanol ligands. The Δν values acquired by FT-IR are in agreement with the single XRD data. Studies on the thermal properties are reported and the complexes are stable to 196, 216, 215, and 201 °C in air, respectively. Two dinuclear Cu(II) complexes have demonstrated catalytic activity on oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone showing saturation kinetics at high substrate concentrations. The diclofenac complexes are investigated as inhibitors of the human cytosolic isoforms hCA I and II. The complexes are good as hCA I inhibitors (Kis of 1.52–55.06 μM) but only moderately efficient as hCA II inhibitors (Kis of 0.23–5.61 μM).

Electrochemical Determination of Copper(II) in Water Samples Using a Novel Ion-Selective Electrode Based on a Graphite Oxide–Imprinted Polymer Composite

ABSTRACT A novel copper(II)-selective electrode based on graphite oxide/imprinted polymer composite was developed for the electrochemical monitoring of copper(II) (Cu2+) ions. The electrode exhibited highly selective potentiometric response to Cu2+ with respect to common alkaline, alkaline earth and heavy metal cations. The composite composition studies indicated that the most suitable composite composition performing the most promising potentiometric properties was 20.0% ionophore (Cu2+-ion imprinted polymer), 10.0% paraffin oil, 5.0% multiwalled carbon nanotubes, and 65.0% graphite oxide. The fabricated electrode exhibited a linear response to Cu2+ over the concentration range of 1.0 × 10− 6–1.0 × 10− 1 M (correlation coefficient of 0.9998) with a sensitivity of 26.1 ± 0.9 mV decade− 1. The detection limit of the fabricated electrode was determined to be 4.0 × 10− 7 M. The electrode worked well in the pH range of 4.0–8.0. The electrode had stable, reversible and fast potentiometric response (3 s). In addition, the electrode had a lifetime of more than 1 year. The analytical applications of the proposed electrode were performed using as an indicator electrode for the potentiometric titration of Cu2+ with ethylene diamine tetraacetic acid solution and for the determination of Cu2+ of spiked river, dam, and tap water samples. The obtained results for potentiometric titration and water samples were satisfactory.

Structural, thermal and morphological properties of a novel poly(acrylamide-co-methacrylic acid)/organoclay nanocomposite

ABSTRACT A novel poly(acrylamide-co-methacrylic acid)/organoclay nanocomposite was prepared and its structural, thermal, and morphological properties were investigated by various techniques. The absence of diffraction peaks for the organomodified-smectite nanocomposite showed that dispersion of the clay nanolayers within the polymer matrix was in the form of an exfoliated nanostructure. Morphological studies confirmed that organomodified-clay dispersed homogeneously in the polymer matrix. Infrared spectroscopy results indicated that the organosmectite is physically dispersed in the polymer network without forming any chemical bonds. The thermal analysis data revealed that there are significant increases in temperatures of decomposition and softening points of polymer with addition of organoclay.

Synthesis and characterization of four novel palladium(II) and platinum(II) complexes with 1-(2-aminoethyl)pyrrolidine, diclofenac and mefenamic acid: In vitro effect of these complexes on human serum paraoxanase1 activity

In this study, the effects of four novel mononuclear palladium(II) and platinum(II) complexes on the activity of human serum paraoxanase1 were examined. First, four novel mononuclear palladium(II) and platinum(II) complexes were synthesized with a nitrogen donor ligand 1‐(2‐aminoethyl)pyrrolidine and nonsteroidal anti‐inflammatory drugs diclofenac, mefenamic acid. These complexes were characterized by spectroscopic, thermal, and elemental analyses. The crystal structures of complex [Pd(2‐amepyr)2](dicl)2 1 and [Pd(2‐amepyr)2](mef)2 3 were determined by X‐ray crystallography. Then, paraoxonase1 enzyme was purified from human serum. The effects of these complexes on enzyme were evaluated in vitro. The complexes consist of the cationic unit and the counterions. The diclofenac and mefenamic acid acted as a counterion in the complexes. It was observed that all the complexes were stable up to high temperatures. These complexes, even at low doses, inhibited the activity of the enzyme with different inhibition mechanisms.

Structural characterization of the silk of two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae)

Abstract The present investigation was undertaken to obtain information about the structural and morphological properties of the silk of two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) by means of the atomic force microscope (AFM), scanning electron microscope (SEM), energy dispersive X-ray spectrophotometer (EDX) and attenuated total reflection Fourier transmission infrared spectroscopy (ATRFTIR) techniques. AFM images show that the shapes of silken threads produced by both female and male mites are similar and have non-uniform cylindrical structure. In general, the appearance of silks produced by female mites is smoother than those of the male mites. In addition, it is determined that the silk threads produced by both female and male individuals have single and double stranded structure. There were differences in the thread dimensions of female and male which could depend on the body size of the mites. However, there is no statistically significant correlation between the body size of the mites and their thread dimensions. The silk material was found to consist predominantly of C, N and O elements and minor fractions of Al, P, Cl and K. The ATR-FTIR spectrum of the silk of two-spotted spider mite exhibited characteristic vibrational modes originating from amid groups, which were attributed to random coil and β-sheet molecular conformation in the protein structure of the silk of two-spotted spider mite. Understanding the features of the two-spotted spider mite silks may be of practical importance for the future studies related to biomaterial and material science.

CCDC 1440608: Experimental Crystal Structure Determination

Related Article: Sema Caglar, Esra Dilek, Bulent Caglar, Ekrem Adiguzel, Ersin Temel, Orhan Buyukgungor, Ahmet Tabak|2016|J.Coord.Chem.|69|3321|doi:10.1080/00958972.2016.1227802

Key words: Sound Diffraction; Lined Duct; Integral Transform; Wiener-Hopf Technique; Expansion Coefficients; Pole Removal Technique

The intercalation of dimethyl sulphoxide (DMSO), pyridine (Py), ethanolamine (Ea), and Nmethyl formamide (NMF) molecules into the kaolinite interlayers led to an appreciable decrease of 3697 cm−1 of the hydroxyl band. The appearance of the peaks at 3662, 3541, and 3504 cm−1 proved that the DMSO species are intercalated between the kaolinite layers through forming H-bonds with internal-surface hydroxyl groups. The intensities of the 942 and 796 cm-1 bending peaks arising from inner-surface hydroxyls decreased and new vibrational features appeared due to the intercalation of the guest species. The d001 value of pure kaolinite was found at 7.18 A° , and the d001 values were seen at 11.26, 11.62, 10.77, and 10.67 °A for kaolinite-dimethyl sulphoxide (K-DMSO), kaolinite-pyridine (K-Py), kaolinite-ethanolamine (K-EA), and kaolinite-N-methyl formamide (K-NMF) composites, respectively. The endothermic differential thermal analysis (DTA) peaks at a temperature of 108 - 334 ◦C reflected the changes in the physicochemical properties of the intercalated species. The thermal stability increase followed the order of K-Py<K-NMF<K-Ea<K-DMSO. Based on the thermal analysis data, the intercalation ratios of the composites above were determined as 80.0, 40.0, 81.6, and 82.0%, respectively. The specific surface areas are affected by the intercalation geometry of the composites within the gallery spacing. The surface areas of the K-DMSO, K-Py, and K-EA complexes increased whereas the surface area of K-NMF decreased with respect to that of untreated kaolinite.