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    Synthesis, characterization of poly(E)-3-amino-4-((3-bromophenyl)diazenyl)-1H-pyrazol-5-ol: Investigation of antibacterial activity, fluorescence, and optical properties
    (2012) Turan, Nevin; Kaya, Esin; Gündüz, Bayram; Çolak, Naki; Körkoca, Hanifi
    The oxidative polycondensation reaction conditions of (E)-3-amino-4-((3-bromophenyl)diazenyl)-1H-pyrazol-5-ol (Schiff base monomer) has been accomplished using NaOCl, and air O 2 oxidants in an aqueous alkaline medium. The optical conductivity, dielectric and optical properties of synthesized poly(Schiff base) were examined. The magnitude of the refractive index decreases with increasing of photon energy up to about 2. 5 eV, then refractive index of the poly(Schiff base) increases with increasing of photon energy. The E 0 and E d values of the poly(Schiff base) were found to be 5.34 and 9.22 eV, respectively. An indirect energy-gap value of the poly(Schiff base) was found to be 0.94±0.009 eV. A direct energy-gap value of the poly(Schiff base) was found to be 1.38±0.01 eV and 1.96±0.009 eV at first region and second region, respectively. Absorption coefficient K changes from 11.87 to 18.25 cm -1. In addition to fluorescence property of poly(Schiff base) was investigated. Finally, poly(Schiff base) and Schiff base monomer were tested for antibacterial activities against some bacteria. © 2012 The Korean Fiber Society and Springer Netherlands.
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    Öğe
    Synthesis, characterization of poly-2- (2-hydroxybenzylideneamino)-6- phenyl-4,5,6, 7-tetrahydrobenzo[b]thiophene-3-carbonitrile: Investigation of antibacterial activity and optical properties
    (2012) Kaya, Esin; Turan, Nevin; Gündüz, Bayram; Çolak, Naki; Körkoca, Hanifi
    The oxidative polycondensation reaction conditions of 2-(2- hydroxybenzylideneamino)-6-phenyl-4,5,6,7-tetrahydrobenzo[b]thiophene-3- carbonitrile were examined. The magnitude of the reflectance of the polymer decreases sharply with increasing of wavelength up to 524 nm, then reflectance of the polymer increases slowly with increasing of wavelength. The refractive index values of the polymer vary from 1.474 to 2.350. The E p and E d values of the polymer were found to be 4.56 and 7.068 eV, respectively. Absorption coefficient K of the polymer is of the order 817.062-1434.77 m -1. Angle values of incidence and refraction of the polymer vary from 57.36 to 66.95° and from 23.05 to 32.65°, respectively. The film-phase thickness of the polymer increases with increasing photon energy. The thickness, d, of the polymer was of the order 439.3-4184.7 Å for 190 and 1100 nm, respectively. The real part of dielectric constant of the polymer decreases slowly with increasing of frequency up to about 600 THz, then the real part of dielectric constant of the polymer increases sharply with increasing of frequency. The real and imaginary parts of dielectric constant of the polymer vary from 2.17 to 5.52 and from 5.81 × 10 -5 to 3.58 × 10 -4, respectively. Finally, polymer was tested for antibacterial activities against some bacteria. Copyright © 2012 Society of Plastics Engineers.
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    Öğe
    The photo-electrical properties of the p-Si/Fe(II)-polymeric complex/Au diode
    (2013) Gündüz, Bayram; Turan, Nevin; Kaya, Esin; Çolak, Naki
    In this study, the Schiff base monomer was prepared by a common condensation method of salicylaldehyde and (E)-3-amino-4-((3-bromophenyl)diazenyl)-1H-pyrazol-5-ol. The poly(Schiff base) was synthesized from the oxidative polycondensation of the Schiff base monomer with NaOCl in an aqueous alkaline medium. After obtaining Schiff base polymer, Fe(II)–polymeric complex with Fe(II) of Schiff base polymer was successfully synthesized. Ligand, monomer, Schiff base polymer and Fe(II)–polymeric complex were characterized using elemental analysis, 1H NMR, 13C NMR, FT IR, GPC, UV–vis and magnetic susceptibility. Then, we fabricated the p-Si/Fe(II)–polymeric complex/Au diode and investigated the electronic and photoconductivity properties of the p-Si/Fe(II)–polymeric complex/Au diode by current–voltage measurements under dark and various illumination conditions. We calculated the electrical and photo-electrical parameters of the p-Si/Fe(II)–polymeric complex/Au diode such as the rectification ratio (r), ideality factor (n), barrier height (?b), Richardson constant (A*), series (Rs) and shunt resistance (Rsh) and photocurrent (Iph), responsivity (R) and photoconductivity sensitivity (S). The obtained n values confirm the presence of a combination of recombination and diffusion currents in the p-Si/Fe(II)–polymeric complex/Au diode. The r, n, ?b, Rs and Rsh values of the p-Si/Fe(II)–polymeric complex/Au diode decreased with increasing illumination intensity. The Iph, R and S values of the p-Si/Fe(II)–polymeric complex/Au diode increased with increasing illumination intensity. The synthesized Fe(II)–polymeric complex exhibits semiconductor property, it can be used in production of the metal-semiconductor (Schottky) diode and it is sensitive to light. The p-Si/Fe(II)–polymeric complex/Au diode exhibits a photoconductivity effect.