FOTOKATALİZÖR ÖZELLİK GÖSTEREN YENİ FTALOSİYANİN- TİTANYUMDİOKSİT NANOKOMPOZİTLER
Thesis Type: Doctorate
Institution Of The Thesis: Yildiz Technical University, Graduate School of Natural and Applied Sciences, Chemistry, Turkey
Approval Date: 2019
Thesis Language: Turkish
Student: Seher Neccaroğlu Işık
Principal Supervisor (For Co-Supervisor Theses): Gülşah Gümrükçü Köse
Co-Supervisor: Oğuzhan Avcıata
Open Archive Collection: AVESIS Open Access Collection
Abstract:The utilization of phthalocyanines having 18-π electron system, one of the macromolecular systems, in various reactions through end groups such as carboxyl and amide is an important factor that increases the application areas of phthalocyanine compounds. The phthalocyanines which have high thermal and chemical stability, have been studied intensively in recent years for their use in many different technological areas such as phototodynamic therapy, solar cell and photocatalytic studies. One of the methods investigated in the development of environmentally friendly systems for the removal of environmental pollution is heterogeneous photocatalysis, and studies have shown that nano-sized TiO2, a semiconductor metal oxide, is the most effective photocatalyst in the breakdown of harmful chemicals in environmental treatment and wastewater. However, because organic pollutants adsorb in very low amounts on the TiO2 surface, they cause limitations in the application of the method. Therefore increasing the photocatalytic efficiency of TiO2 by surface modification is an alternative for the solution of the problem. In this thesis study, synthesis of symmetrical and unsymmetrical tetra substitue phthalocyanines, bearing carboxylic acid groups at the peryphral positions by cyclotetramerisation of the phthalonitrile derivatives is aimed. In the first part of the study, 4-nitrophthtalonitrile (1) and 6-hydroxy-2-napthoic acid (2) were reacted under suitable conditions and with the nucleophilic aromatic substitution reaction, the corresponding 4-(6-carboxy-2-naphthoxy)phthalonitrile (3) a new compound that was not previously found in the literature was synthesized. The ligand (3) was reacted with Zn(CH3COO)2, CuCl2, CoCl2 and Ni(CH3COO)2 to yield symmetrically tetra substituted metallo (6, 7, 8, 9) and metal-free (10) phthalocyanines bearing carboxylic acid groups at the peripheral positions. In the second part of the study, 4-nitro-phthalonitrile (1) and 2,4-di-tert-butylphenol (4) were reacted in dry DMF to yield 4-(2,4-di-tert-butylphenoxy) phthalonitrile (5). The ligand (5) was reacted with 4-(6-carboxy-2-naphthoxy)phthalonitrile (3). Unsymmetrical metallophthalocyanines of [2,9,16-tri-(2,4-di-tert-butylphenoxy)-23-(4-[6-carboxy-2-naphthoxy])-phthalocyaninato zinc (II), cobalt (II), cupper (II), nickel (II) (11, 12, 13 ve 14) and metal-free (15) phthalocyanines which carry peripheral 2,4-di-tert-butylphenoxy substituents on each of three of the benzenoid groups while the fourth one carries 6-carboxy-2-naphtoxy groups, were synthesized under statistical condensation conditions. The structures of synthesized symmetrical and unsymmetrical mono phthalocyanine complexes were elucidated by FT-IR, UV-Vis, 1H-NMR and MALDI-TOF MS and LC MS spectroscopy techniques. In the third part of the study, thin films have been produced where symmetrical phthalocyanine compounds (6-10) that carry –COOH groups at their ends, are used as sensors and a study was made for the detection of 7 different evaporating organic vapors, n-hexane, dichloromethane, diethylamine, ethanol, methanol, isopropanol and acetone. Ethanol adsorption onto the thin films of these compounds and the effects of operating temperature on the sensing properties were also studied. The sensing data show that all of the films of phthalocyanine compounds show response to ethanol, among which, [2,9,16,23-tetra-(4-(6-carboxy-2-naphthoxy)-phthalocyaninato-nickel (II)] based sensor show the highest response, demonstrating central metal atom dependence of ethanol sensitivity. Surface topography of the sensing films were analyzed by atomic force microscopy. In the last part of the study, symmetric and asymmetric phthalocyanine compounds were loaded on nano TiO2. The physical and chemical properties of synthesized nanocomposites were characterized by XRD, FTIR, FEG-SEM, EDX, BET, UV-DRS. In order to investigate the photocatalytic properties of synthesized nanocomposite materials, the effects of methylene blue on the photocatalytic degradation of cationic dyes under visible light were investigated.