Miscellaneous Papers by Burak Coban
Journal of Polymer Research, 2010
Microbial bioelastomers prepared by the autoxidation of the unsaturated medium-long chain length ... more Microbial bioelastomers prepared by the autoxidation of the unsaturated medium-long chain length co-poly-3-hydroxyalkanoate’s (mlcl-PHAs) based on soybean oily acids (Sy) have been reported. Pseudomonas oleovorans were grown on a series of the mixture of octanoic acid (OA) and Sy with the weight ratio of 20:80, 28:72 and 50:50 in order to obtain unsaturated mlcl-copolyesters coded PHO-Sy-2080, PHO-Sy-2872, and PHO-Sy-5050, respectively. The microorganism was also grown on the mixture of Sy and 10-undecenoic acid (UA) with the weight ratio of 50:50 to obtain unsaturated copolyester coded PHU-Sy-5050. The PHAs obtained were characterized by 1H NMR and GC-MS techniques. Double bond contents of the unsaturated PHAs obtained were varying between 0.8 to 20 mol %. Autoxidation of the unsaturated copolyesters were carried out on exposure to air at room temperature in order to obtain new biomaterials whose mechanical strength was improved. Autoxidation kinetics, shelf life, mechanical and thermal properties of these biomaterials were evaluated.
Structural studies of complex compounds of 6,6’-diacetyl-2,2’-bipyridine dioxime with copper(I/II), platinum(II), and palladium(II) metal ions
Turkish Journal of Chemistry 35:25-36., 2011
The tetradentate ligand 6,6-diacetyl-2,2-bipyridine dioxime (L) was obtained in high yield by the... more The tetradentate ligand 6,6-diacetyl-2,2-bipyridine dioxime (L) was obtained in high yield by the condensation reaction of 6,6-diacetyl-2,2-bipyridine with hydroxyl amine in alkaline solution. Density functional calculations and 3D modeling of the structure at the B3LYP/6-31G(d) level of theory for L revealed that the energy difference between the global trans conformer (trans-L), which possesses the C2h point group, and the distorted cis conformer (cis-L) was 5.214 kcal/mol. Synthesis and characterization of the metal complexes with Cu(I), Cu(II), Pt(II), and Pd(II) metal ions were reported. L acted as a N4 - donor ligand to coordinate to the metal centers via N atoms of the 2,2-bipyridine and the imine moieties to afford tetrahedral complex [CuI L]PF6 (1), distorted octahedral complex [CuII L(OH2)2 ](NO3)2 (2), and square-planar complexes [Pt II L]Cl 2 (3) and [PdII L]Cl (4), respectively. The CHN analysis for 1 implies that L coordinated to 2 copper(I) ions as a bridging ligand to form a dinuclear metal complex, [Cu2L2 ]2+ , due to the twisting of the coordinated bonds exposed by the tetrahedral geometry preference for the metal ion. The ligand formed intramolecular hydrogen bonds between the oxime groups in 4, as revealed by the spectroscopic studies. The most stable conformations of the compounds were obtained by using the molecular mechanics optimization feature in CAChe software with an augmented MM2 force field.
Effects Of Pellet And Extruded Feed On Fatty Acid Composition Of European Sea Bass (Dicentrarchus Labrax) Using HRGC-MS
Fresenius Environmental Bulletin 18:112-116., 2009
Total lipid amount and fatty acid composition were determined and compared for cultivated Europea... more Total lipid amount and fatty acid composition were determined and compared for cultivated European sea bass (Dicentrarchus labrax) from Turkey, which were fed with pellet and extruded commercial feed two or three times a day. Fatty acid analyses were carried out by gas chroma-tography-mass spectrometry. Among total fatty acids, palmitic (16:0), palmitoleic (16:1n-7), oleic (18:1n-9), linoleic (18:2n-6), eicosapentaenoic acid = EPA (20:5n-3) and docosahexaenoic acid = DHA (22:6n-3) were found to be the predominant fatty acids. The fish which received extruded feed (three times a day) had a slightly higher n-3/n-6 ratio of 1.41 compared to the other feeding types. It was found that the extruded feed given two times a day as fish diet resulted in the highest amounts of EPA, DHA, and total n-3 fatty acids.
Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of... more Pseudomonas oleovorans was grown with either 10-undecenoic acid alone or the equimolar mixture of octanoic acid and 10-undecenoic acid to obtain unsaturated poly(3-hydroxy alkanoates) (PHA)s; poly(3-hydroxy-10-undecenoate) (PHU) and poly(3-hydroxyoctanoate-co-3-hydroxy-10-undecenoate) (PHOU), respectively. The addition of bromine to olefinic double bond, by reacting the unsaturated PHA with bromine in homogeneous solution in dark, was readily carried out. The brominated PHA was reacted with polyethylene glycol (PEG) in the presence of a base to obtain PHA-g-PEG graft copolymers. The polymers were characterized by 1H NMR and FTIR spectroscopy, gel permeation chromatography (GPC), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
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Miscellaneous Papers by Burak Coban