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  • Küçük Resim
    Öğe
    Synthesis, characterization, reaction conditions, conductivity and thermal properties of poly(phenoxy-imine)s containing methoxy unit
    (Elsevier, 2023) Kaya, İsmet; Koca, Semra; Karaer Yağmur, Hatice
    Two Schiff bases were accomplished through a condensation reaction between salicylaldehyde and ortho-anisidine or para-anisidine. The oxidative polycondenzation reaction conditions of 2-[(2-methoxyphenylimino)methyl)phenol (SB1) and 2-[(4-methoxyphenylimino)methyl] phenol (SB2) were determined by H2O2, NaOCl, and air oxidants in an aqueous alkaline medium at different temperatures and reaction times. The % conversion ratios (oligo-2-[(2-methoxyphenylimino)methyl)phenol (oligo-SB1) and oligo-2-[(4-methoxyphenylimino) methyl]phenol (oligo-SB2) were studied in optimum reaction conditions. The structural characterizations of compounds were defined with H-1-C-13-NMR, FT-IR, and size exclusion chromatography (SEC) measurements. Electrochemical and thermal features of compounds were studied by UV-Vis spectroscopy, cyclic voltammetry (CV), FE-SEM, and TG-DTA, respectively. Moreover, conductivity and surface morphologies measurements of oligo-SB1 and oligo-SB2 were carried out by four-point probe technique and FE-SEM, respectively. The conductivity values of the oligo-SB1 and oligo-SB2 were found to be 4.12x10(-6) S cm(-1) and 4.87x10(-4) S cm(-1), respectively. The residue amounts of oligo-SB1 and oligo-SB2 at 1000 degrees C were found as 45.52% and 55.46%, respectively. Thermal stability, optical properties and conductivity values of oligo-SB2 were better than oligo-SB1. (C) 2022 Elsevier B.V. All rights reserved.
  • Küçük Resim
    Öğe
    The green synthesis of oligo(azomethine)s based on p-anisidine and o-anisidine: reaction conditions, electrochemical and thermal properties
    (Taylor & Francis Inc, 2022) Kaya, İsmet; Koca, Semra; Karaer Yağmur, Hatice
    Schiff bases and their conjugated oligo(azomethine)s have been synthesized via condensation and oxidative polycondensation of o-anisidine (OA) with 2-hydroxy-1-naphthaldehyde (2-HNA) and p-anisidine (PA) with 4-hydroxy benzaldehyde (4-HBA), respectively. The oxidative polycondensation reaction conditions of 1-[(2-methoxyphenylimino)methyl]naphthalen-2-ol (1,2-MPIMN) and 4-[(4-methoxyphenylimino)methyl]phenol (4,4-MPIMP) were studied by oxidants such as air and aqueous solutions of H2O2 and NaOCl in different concentrations in an aqueous alkaline medium between 50 degrees C and 90 degrees C at different reaction times. The structures of polymers were confirmed by FT-IR, UV-Vis and H-1-C-13-NMR measurements. The molecular weights and surface morphologies of oligomers were determined by size exclusion chromatography (SEC) and scanning electron microscopy (SEM), respectively. Electrochemical and thermal features of compounds were studied using UV-Vis spectroscopies, cycling voltammetry (CV), and TG-DTA. The mass losses values of the 1,2-MPIMN, oligo(1,2-MPIMN), 4,4-MPIMP, and oligo(4,4-MPIMP) were calculated from the thermogravimetric curves as 98.00%, 53.52%, 69.00%, and 58.70%, respectively, at 1000 degrees C. The HOMO, LUMO levels, electrochemical (E-g(')), and optical band gap energies (E-g) values of the compounds were calculated from CV and UV-Vis data. The E-g(') values of 1,2-MPIMN, oligo(1,2-MPIMN), 4,4-MPIMP, and oligo(4,4-MPIMP) were found to be 2.64, 1.54, 2.31, and 2.16 eV, respectively. The electrical properties of monomers and oligomers were determined at room temperature.