The synthesis of the nitrogen containing heterocyclic compounds is one of the leading research areas throughout the organic chemistry due to their significant activities in biological systems. Among the various biologically active molecules, pyridine-fused ring systems are of prime importance on the grounds of their proven clinical roles. The coupling reactions with 6-membered heterocyclic compounds and diazepines gave rise to new pharmalogical compounds in recent years. Therefore, our object was the synthesis of pyridine-fused 6- and 7-membered heterocycles. Starting from bromopyridine, two different methods were applied for the synthesis of target compounds. In the first part of the this thesis, coupling products were synthesized using Sonogashira coupling reaction. After synthesis of the coupling derivatives, ring-closure under the basic conditions generated the heterocyclic units without using any catalyzer. In the second part of study, nicotinic acid and pyridopyranone derivatives were synthesized by using intramolecular cyclization reactions. The formed products were conscientiously purified and characterized by means of spectroscopics method.

Dopamine is a neurotransmitter found in central nerve system which has a vital role for human health. Dopamine oxidation in body is an important issue since it may form reactive metabolites which can be toxic to the cell. Surface-enhanced Raman scattering (SERS) is currently recognized as one of the most sensitive spectroscopic tools, which can be exploited for ultrasensitive chemical and biological detection, addition to providing structural information on the systems of interest. SERS of dopamine displays three strong bands at 1269, 1331 and 1479 cm-1. These bands are the signature of dopamine molecule. The most intense band at 1479 cm-1 is contributed mainly from stretching of the carbon-carbon bond to which the oxygens are attached. A bidentate silver-dopamine complex or in general bidentate metal-dopamine complex formation is required for the SERS detection of dopamine and other catecholamines. In other words, for acquiring the characteristic dopamine SERS signature, both of the catechol oxygens should take a part in the adsorption of dopamine to the silver metal surface which is used as a SERS substrate. Therefore, the reactivity of different oxidation forms of dopamine for the formation of bidentate silver-dopamine complex was investigated by obtaining their SERS spectra and following the characteristic C-C ring vibration at 1479 cm-1. Dopamine oxidation was carried out electrochemically, utilizing platinum and silver electrodes as working electrode. Oxidation products formed were identified with UV-vis Spectrometer. Also, silver metal ions were used to oxidize dopamine, leading to formation silver nanoparticles. Dopamine functionalized silver nanoparticles were characterized by Scanning Electron Microscope, Transmission Electron Microscope, UV-vis Spectrometer. Surface- enhanced Raman spectra of polydopamine on the surface of synthesized silver nanoparticles and the electrodeposited dopamine on the porous surface of silver electrode were also obtained.

ABSTRACT LEAD(II) AND AMMONIUM EXCHANGE on Na-FORM of G&Ouml / RDES CLINOPTILOLITE ASiroglu, Sedat M.S., Department of Chemical Engineering Supervisor Prof. Dr. Hayrettin Y&uuml / cel September 2006, 89 pages Natural zeolites, especially clinoptilolite, have the ability of removing certain cations from wastewater by utilizing ion exchange and adsorption. In this study, ion exchange behaviour of G&ouml / rdes clinoptilolite at particle size range (0.5-0.25 mm) for lead and ammonium removal was investigated to establish the conditions under which clinoptilolite may be used in an economical and effective manner. Experiments were divided into two parts. Batch and continuous (column) experiments were carried out. In the batch experiments, experimental isotherms of NH4+-Na+, Pb2+-Na+ binary systems and NH4+-Pb2+-Na+ ternary system were obtained as the graphs of equivalent fractions of exchanging cation in solution versus equivalent fractions of cation in zeolite. It was determined that clinoptilolite has affinity for Pb2+ and NH4+ ions. Finally, the selectivity sequence of G&ouml / rdes clinoptilolite in the presence of Pb2+ and NH4+ together was determined as Pb2+ &gt / NH4+ &gt / Na+. In the column studies, removal of lead, ammonium and simultaneous removal of lead-ammonium solutions were investigated. The loading flow rates were selected as 8, 15, and 30 mL/min. The ion exchange capacity of clinoptilolite for lead and ammonium removal showed good performance. Flow rates at 8, 15, 30 mL/min, breakthrough capacities were found as 0.398 meq/g (Pb2+) and 0.337 meq/g (NH4+), 0.299 meq/g (Pb2+) and 0.297 meq/g (NH4+), 0.197 meq/g (Pb2+) and 0.198 meq/g (NH4+) for lead-ammonium-sodium system and corresponding column efficiencies were 63.36%, 51.38%, 34.05%, respectively.

Zeolites are crystalline, hydrated aluminosilicate minerals that are characterized by their ability to exchange some of their constituent cations with cations in aqueous solutions, without a major change in their crystalline structure. Clinoptilolite is the most abundant ype of zeolite and it has received extensive attention due to its favorable selectivity for mmonium and certain heavy metal cations. The aim of this study is to investigate the binary and ternary (multicomponent) ion xchange behavior of sodium form of G&ouml / rdes type clinoptilolite for ammonium,cadmium and sodium ions. For this purpose, NH4 +-Na+,Cd2+-Na+ binary systems and NH4 +-Cd2+-Na+ multicomponent system were investigated both in batch and column systems at 0.1 and 0.01 constant total normality respectively and at 250C constant temperature. As a result of binary and ternary experiments, clinoptilolite&rsquo / s affinity for both ions but greater affinity to NH4+ ion than Cd2+ ion was observed and the selectivity sequence of G&ouml / rdes clinoptilolite was determined as NH4+&gt / Cd2+&gt / Na+ in binary and multicomponent batch and column operations. Additionally, total ion exchange capacities and maximum exchange levels of G&ouml / rdes clinoptilolite for both ions were determined in batch systems whereas breakthrough capacities and column efficiencies (for three different flow rates) were determined in column systems. Finally, it was concluded that the increase of the flow rate reduced the breakthrough capacities and column efficiencies of G&ouml / rdes clinoptilolite for ammonium and cadmium ions in multicomponent column systems involving more than one cation.

Level densities and spin cut-off factors have been investigated within the microscopic approach based on BCS Hamiltonian. In particular the spin cut-off parameters have been calculated at neutron binding energies over a large range of nuclear mass using the BCS theory. The results are compared with their corresponding macroscopic values. It is found that the values of spin cut-off parameter do not increase smoothly with A as expected based on macroscopic theory. Instead, the values of spin cut-off parameter show structures re&deg / ecting the angular momentum of the shell model orbitals near the Fermi energy. The spin cut-off parameter has also been computed from the knowl- edge of nuclear level density, at neutron binding energy, Bn and the average s-wave neutron spacing. The values of spin cut-off parameter are compared with their corresponding values from the model calculations. The in&deg / uence of the isospin in nuclear level density in particular the isospin cut-off parameter has also been investigated and are compared with their corre- sponding spin cut-off parameters.

Controlled drug delivery systems deliver drugs at predetermined rates for extended periods. Although there are various types such as capsules, tablets etc, micro and nano spheres are the most commonly used systems. In this study, a set of chitosan-polyvinylpyrrolidone (CH-PVP) microspheres containing different amounts of polyvinylpyrrolidone as semi inter penetrating networks (semi-IPN) were prepared as controlled release systems. Emulsification method was applied for the preparation of microspheres and some of them were conjugated with a monoclonal antibody which is immunoglobulin G (IgG). CH-PVP films were also prepared by solvent casting method with the same composition as in the microspheres and, mechanical and surface properties of the films were examined. Prepared microspheres were characterized by SEM, stereo and confocal microscopes. Some microspheres were loaded with a model chemotherapeutic drug, 5-Fluorouracil (5-FU), and in-vitro release of 5-FU were examined in phosphate buffer solutions (pH 7.4, 0.01 M.) It was shown that for semi-IPN samples release was faster compared to pure CH samples and the total release was achived 30 days for CH:PVP-2:1, CH:PVP-3:1 semi-IPNs and CH microspheres and 27 days for CH:PVP-1:1 semi-IPN microspheres. The antibody conjugated microspheres were targeted to MDA-MB (human causasian breast carcinoma cancer cells and coculture cells in culture medium. For the CH-PVP films, it was obtained that as the amount of PVP increased, hydrophobicity as well as mechanical strength of the system was decreased.

This study presents studies on camptothecin (CPT), a potent antitumor agent in order to improve its stability and solubility without reducing its activity. The work describes the modification of camptothecin at 20-OH position a new strategy to overcome the stability and solubility problems of the free drug. Camptothecin is conneted to linker that could be processed to a terminal thiol group and this thiol group was connected to gold surface, to obtain CPT-gold nanoparticles. In the first part of the study / undecenol was chosen as the starting material and reacted with azobisisobutylonitrile to obtain S-11-hydroxyundecyl ethanethioate. 11-hydroxyundecyl ethanethioate was reacted with NaOMe to synthesize the target linker 11, 11&rsquo / -disulfanediyldiundecan. After synthesis of the target linker, the 20- OH functional group of CPT was replaced with this linker to obtain 20- (11, 11&rsquo / -disulfanediyldiundecan) - captothecin. The second part of the study, gold nanoparticles were synthesized by using HAuCl4 solution and the camptothecin derivative containing thiol group at 20-OH position was connected to the gold surface.

The microstructural, electrochemical and optical properties of sol-gel derived tungsten oxide electrochromic coatings have been investigated. Coatings were formed by spinning of tungsten metal based aqueous sol on glass with native ITO layer. Three sol formulations / acetylated peroxotungstic acid (APTA), peroxotungstic acid (PTA) and titanium-doped peroxotungstic acid (Ti-PTA) were employed to obtain 200-300 nm thick multi-layered coatings. Material and electrochromic characterization of the coatings have been performed by DSC, XRD, SEM, cyclic voltammetry and UV-Vis spectroscopy. The electrochromic performance of the WO3 coatings was influenced by calcination temperature, by sol chemistry and by the adsorbed water content. For all sol formulations the coatings calcined at 250 &deg / C were amorphous and have shown better performance compared to crystalline counterparts calcined at 400 &deg / C. High calcination temperature also leads to formation of WO3 nanocrystals for APTA and PTA derived coatings, titanium doping retards crystallization. Presence of acetic acid as in APTA sol improved the electrochromic and electrochemical performance. This was related to removal of organics- acetic acid and peroxo ligands- during calcination, which results in an open W-O network providing more ion insertion sites. The water adsorption affected the electrochromic performance in different ways for the coatings calcined at 250 &deg / C and 400 &ordm / C. The amorphous coatings with limited structural water removal and excessive hydroxyl groups tend to crystallize by condensation of W-OH groups upon storage in open atmosphere, therefore exhibiting degrading electrochromic activity with aging. Conversely, hydroxyl groups enhanced Li+ ion insertion for the stable crystalline coatings calcined at 400 &deg / C.

A phytochemical investigation on methanolic extract of roots of yellow rose led to the isolation of a catechin gallate. The crude extract first underwent fractionation using petroleum ether, chloroform, ethylacetate, butanol with water as solvents in their respective order. The emerging solvent fractions were subjected to further separation using lipophilic sephadex (LH-20), and silica gel column chromatography to isolate pure compounds. Analytical thin layer chromatography (TLC) was used to confirm the presence of a catechin in butanol fraction. Purified catechin compound was subjected to 2,2-diphenyl-1-picrylhydrazyl (DPPH) experiment to determine its Radical Scavenging Capacity, which was found quite promising. Chemical structure of purified compound was established by using Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) experiments.

The healing effects of fillers on bitumen have been known for many years. In this study, the effects of fillers, e.g. manganese dioxide, barium sulfate, perlite and vermiculite, and filler concentrations on morphological, mechanical, flow and sound insulation characteristics of bitumen were examined. It was also aimed to improve the mechanical and sound insulation properties of bituminous composites. Bituminous composites were prepared by using Brabender Plasti-Corder. Mixing was made at 130&deg / C with 60 rpm for 20 minutes. 20/30 and 50/70 penetration grades bitumen, SBS polymer and CaO used in the composites were kept constant. While the amount of CaCO3 was decreased, other fillers (i.e., MnO2, BaSO4, perlite and vermiculite) were added in the same proportion to investigate their effects. According to the test results, all fillers were covered by bitumen as observed in SEM figures. MnO2 composites did not give good results in the tests and they were very brittle. While perlite seemed to have good mechanical properties, it was too viscous to be processed easily. Increase in the amount of vermiculite in the composite caused adverse effects on the rheological properties of composites. However, vermiculite composites provided a remarkable sound insulation in terms of the sound damping ratios. BaSO4 composites gave the best results in the mechanical, flow and sound insulation tests.