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Öğe Media effects on the optical properties of proton donor group containing azobenzene derivatives(ELSEVIER SCIENCE BV, 2009) Oertel, Ulrich; Mart, Hasan; Komber, Hartmut; Boehme, FrankA series of hydroxy and carboxy group containing azobenzene compounds were synthesized and investigated by UV-vis and fluorescence spectroscopy. It could be shown that the ambient medium exerted a strong influence on the absorption behavior and the trans-cis isomerization behavior of the azo compounds. Especially in the case of hydroxy group functionalized azobenzenes, deprotonation with NaOH or a polymeric base changed the spectral behavior of the compounds remarkably. A strong bathochromic shift of the dyes' longest wavelength absorption band was observed. Furthermore, the influence of different solvents and different polymeric matrices on the trans-cis isomerization behavior of the azobenzenes was investigated. The results are discussed in terms of utilization of the azo dyes as probe molecules for interactions in polymer blends. (C) 2009 Elsevier B.V. All rights reserved.Öğe New soluble azophenol polymers prepared by oxidative polycondensation(WILEY, 2007) Canakci, Dilek; Tuncel, Mehmet; Mart, Hasan; Serin, SelahattinNew azophenol polymers (P-1, P-2 and P-3) were synthesised by the oxidative polycondensation (OP) reaction of three different azophenol monomers in aqueous alkaline medium with NaOCl as the oxidant. The monomers and the polymers were characterised by elemental analyses, and UV-visible, Fourier transform infrared, H-1 NMR and C-13 NMR spectroscopic studies, which revealed that the polymers synthesised by OP are composed of oxyphenylene (C-O-C) and phenylene (C-C) units. The polymers obtained are soluble in dimethylformamide and dimethylsulfoxide. Average molecular weights of the polymers were determined by gel permeation chromatography. Additionally, P-2 and P-3 are soluble in water and methanol. On the basis of thermogravimetric analyses, 5 and 50% weight-loss temperatures of the polymers were found to be 218, 700 (P-1), 263, 609 (P-2) and 100, 809 degrees C (P-3), respectively, suggesting a high thermal stability. Thermal analyses using differential scanning calorimetry revealed that the azophenol polymers are highly amorphous, and melting peaks were not observed in the heating cycles. This suggests that all the polymers are highly amorphous. The azophenol polymers show a reversible trans-cis-trans isomerisation process. These properties of the polymer could be promising for their technological usage. (C) 2007 Society of Chemical Industry.Öğe Oksidatif polikondensasyon metoduyla yeni tip oligomerlerin sentezi ve karakterizasyonu(Niğde Üniversitesi, 2002) Mart, Hasan; Yürük, Hüseyin; Saçak, MehmetÖZET OKSİDATİF POLİKONDENSASYON METODUYLA YENİ TİP OLİGOMERLERİN SENTEZİ VE KARAKTERİZASYONU MART, Hasan Niğde Üniversitesi Fen Bilimleri Enstitüsü Kimya Anabilim Dalı Danışman : Prof.Dr. Hüseyin YÜRÜK 2. Danışman : Prof.Dr. Mehmet SAÇAK Temmuz 2002, 97 sayfa Bu çalışmada 4-hidroksibenzaldehit (HBA)'in hidrojen peroksitle oksidatif polikondensasyon reaksiyonu şartları ve ürünleri incelendi. Bu reaksiyonda optimum reaksiyon şartı belirlendi. Oligo-4-hidroksibenzaldehit (OHBA), sulu alkali ortamda, hidrojen peroksitle, 75-95 °C arasında HBA'in oksidatif polikondensasyonuyla elde edildi. Ürünler, H-NMR, FT-IR, UV-Vis ve elementel analiz yöntemleriyle karakterize edildi. Hidrojen peroksit ortamında sentezlenen OHBA'in, sayıca ortalama molekül ağırlığı, ağırlıkça ortalama molekül ağırlığı ve polidisperslik derecesi sırasıyla 5171, 8625 ve 1.668 olarak bulundu. Optimum reaksiyon şartlarında reaksiyon ürünü verimi % 58 olarak bulundu. Termogravimetrik analizler OHBA'in termooksidatif bozunmaya dirençli olduğunu gösterdi. OHBA'in % 5, % 50 ve % 51.8 ağırlık kayıpları sırasıyla 170, 845 ve 900 °C olarak bulundu. Ayrıca OHBA'in anilin, 2-kloranilin, 4-aminotoluen, 2-aminotoluen, 4-nitroanilin ve 2-aminofenolle kondensleşme reaksiyonlarıyla yeni oligomer Schiff bazları sentezlendi ve sentezlenen bu bileşiklerin yapı ve özellikleri belirlendi. Anahtar sözcükler: 4-hidroksibenzaldehit. Oksidatif polikondensasyon. Oligomer Schiff bazları ıııÖğe Oxidative polycondensation reaction(VSP BV, 2006) Mart, HasanIn the last few years, some monomers such as phenols, anilines, pyridines, naphtols, Schiff bases and azo phenols have been subjected to oxidative polycondensation (OP) using NaOCl, H2O2 and air O-2 as the oxidants in aqueous alkaline or aqueous acidic medium. This resulted in oligomers with potential useful properties. The major reason behind these investigations was the economic and environmentally benign reaction process of OP. Therefore, this review diccusses OP and the obtained oligomers in detail. Additionally, chemical structures, physical properties, UV-Vis, FT-IR, H-1- and C-13-NMR analyses, thermal properties and coupling mechanism of all oligomers synthesized via OP are discussed and compared to those of polymers prepared by other oxidative methods. The probable potential applications of the obtained polymers and oligomers, such as antistatic and semi-conductivity, fluorescent, photoresist, opto-electronic, electrochromic, antimicrobial and photoresponsive properties, are also discussed in the last section.Öğe Synthesis and characterization of conducting graft copolymers based on oligophenols(TAYLOR & FRANCIS INC, 2006) Sahmetlioglu, Ertugrul; Arikan, Ufuk; Toppare, Levent; Yuruk, Huseyin; Mart, HasanOligo-2-aminophenol (OAF) was synthesized with oxidative polycondensation of 2-aminophenol and hydrogen peroxide in an aqueous alkaline medium at 80 degrees C. Oligo-2-aminophenol with thiophene side groups (TOAF) was obtained by the reaction of OAF and thiophene-3-acetic acid. Graft copolymers of TOAF and pyrrole were synthesized by electrochemical polymerization in p-toluene sulfonic acid (PTSA)/water medium. Characterization of the graft copolymer (TOAF-g-Py), was carried out by combination of techniques including thermal gravimetry (TGA), cyclic voltametry, size-exclusion chromatography, H-1-NMR and FTIR. The conductivities were measured by the four-probe technique.Öğe Synthesis and characterization of thermally stable oligomer-metal complexes of copper(II), nickel(II), zinc(II) and cobalt(II) derived from oligo-p-nitrophenylazomethinephenol(CHEM SOC ETHIOPIA, 2006) Vural, Ufuk S.; Mart, Hasan; Demir, H. Okkes; Sarioez, Ozlem; Muradoglu, Vefa; Koc, M. CihangirThermally stable metal complexes based on oligomers were prepared by the reaction between oligo-p-nitrophenilazomethinephenol (ONPAP) and Cu(II), Ni(II), Zn(II) and Co(II) ions. The properties of oligomer-metal complexes were studied by elemental, FT-IR and magnetic moments analyses. The thermal stabilities of the oligomer-metal complexes were compared by thermogravimetric (TG) and differential thermal (DTA) analyses. According to TG, oligomer-metal complexes were stable against to temperature and thermooxidative decomposition. The weight losses of oligomer-metal complexes were found to be 5 and 50 % at 200 and > 850 (Cu(II)), 172 and 600 (Ni(II)), 252 and > 850 (Zn(II)) and 174 and 510 (Co(II)), degrees C, respectively. Based on half degradation temperature parameters Cu(II) and Zn(II) complexes were more resistant than the others.
