Preparation of highly thermally stable and conductive Schiff base polymer: Molecular weight monitoring and investigation of antimicrobial properties

WOS: 000430763000005A novel thermally stable polyazomethine with phenol group, Poly(4-[[4-(dimethylamino)benzylidene] amino]phenol) P(4-DBAP), was synthesized from 4-[[4-(dimethylamino)benzylidene]aminc]phenol) (4-DBAP) in aqueous alkaline medium via oxidative polycondensation with NaOCl, H2O2, and O-2 oxidants. The change of the yield and molecular weight distribution of P(4-DBAP) with oxidant type and concentration, monomer concentration, and polymerization temperature and time were analyzed. The structures of the monomer and polymer were confirmed by UV-Vis, FTIR, H-1-NMR, C-13-NMR and TGA techniques. The conductivity value of the polymer which was doped with iodine vapor for 24 h was reached 3.2 x 10(-5)S/cm and 1.1 x 10(-4) S/cm values by increasing 107 and 108 folds compared to the initial conductivity value at 20 degrees C and 60 degrees C, respectively. This conductivity value which was measured at 20 degrees C is the highest value reported in the literature for polyazomethines having phenol group in such a short time and at low temperature. Moreover, antimicrobial activity test was performed for 4-DBAP and P(4-DBAP) against Sarcina lutea, Enterobacter aerogenes, Escherichia coli, Enterococcus Feacalis, Klebsiella pneumoniae, Bacillus subtilis bacteria, and Candida albicans and Saccharomyces cerevisiae fungi. Although both monomer and polymer showed antibacterial activity, the polymer was more efficient compared to the monomer. (C) 2018 Elsevier B.V. All rights reserved.Ankara University Research Funds [13B4240008]We would like to thank Dr. Ashabil AYGAN (Kahramanmaras Sutcu Imam University, Faculty of Arts and Science, Department of Biology, Kahramanmaras, Turkey) for his help on antimicrobial tests. Moreover, we are grateful to Ankara University Research Funds for the financial support to this study (Project No. 13B4240008)

Synthesis and properties of novel Schiff base oligomers based on oligo-4-hydroxybenzaldehyde

Condensation of oligo-4-hydroxybenzaldehyde with aniline, 2-chloroaniline, 2-aminophenol, 2-aminotoluene, 4-aminotoluene, and 4-nitroaniline gave the corresponding Schiff base oligomers (OFAP, OKAP, OHAP, OOAP, OTAP, and ONAP, respectively). The products were characterized by H-1 NMR, Fourier transform infrared, ultraviolet-visible, and elemental analyses. The number-average molecular weight, mass-average molecular weight, and polydispersity index (PDI) values of the Schiff base oligomers were determined. Thermogravimetric analysis was used to compare the thermal stability of the oligomers, which showed the Schiff base oligomers to be resistant to thermooxidative decomposition. Weight loss of 5% and 50% occurred at temperatures of 122 and 475 degreesC; for OFAP, at 118 and 453 degreesC; for OKAP, at 182 and 491 degreesC; for OHAP, at 150 and 452 degreesC; for OOAP, at 132 and 401 degreesC; for OTAP, and at 193 and 414 degreesC for ONAP. (C) 2004 Wiley Periodicals, Inc

Highly effective and recoverable Pd(II) catalyst immobilized on thermally stable Schiff base polymer containing phenol group: Production, characterization and application in Suzuki coupling reactions

WOS: 000432600900011In this study, a novel highly efficient, recoverable, sustainable, and thermally stable Schiff base polymer-Pd(II) catalyst was designed for Suzuki coupling reactions in synthesis of biaryl compounds for the first time. Firstly, a novel Schiff base polymer containing phenol, Poly(4-((pyridine-2ylimino) methyl) benzene-1,3-diol) (P (4-PMB)), which was used as a support material in catalyst design, was synthesized in aqueous alkaline medium via oxidative polycondensation of 4-((pyridine-2-ylimino) methyl) benzene1,3-diol (4-PMB) with NaOCl oxidant. The effects of oxidant concentration, polymerization temperature, and time on yield and molecular weight of the polymer were investigated. The structures of the synthesized compounds were illuminated by UV-Vis, FTIR, (HNMR)-H-1, XRD, TG/DTG, and SEM/EDAX methods. Then, Pd(II) complex of P (4-PMB) was produced, and its catalytic performance was tested in the synthesis of various biaryl compounds by Suzuki reactions using microwave irradiation technique which is a highly effective, fast, solvent-free and green method. The designed Pd(II) catalyst exhibited superior catalytic effect against syntheses of various biaryl compounds with high conversion yields (99%) and very low catalyst loading (0.01 mol%) for 5min. Recyclability and reproducibility tests showed that the catalyst could be reused for seven successive runs without any great loss of its catalytic performance (84%). (C) 2018 Elsevier B.V. All rights reserved.Aksaray University Research Funds [2016-022]The authors would like to thank Aksaray University Research Funds for the financial support of this work (Project No. 2016-022)

Polyaniline grafted polyacylonitrile conductive composite fibers for reversible immobilization of enzymes: Stability and catalytic properties of invertase

WOS: 000267619700014Polyacylonitrile fibers (PAN) surfaces were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The effect of aniline concentration on the grafting efficiency and on the electrical surface resistance of PAN/PANI composite fibers was investigated. The surface resistance of the conductive composite fibers in this work was found to be between 8.0 and 0.5 k Omega/cm. As the amount of grafted PANI increased on the PAN fibers the electrical resistance of composite fibers decreased. The PAN/PANI composite fibers were characterized by SEM and FTIR studies. Composite PAN/PANI fibers were used for reversible immobilization of invertase. The immobilization efficiency and the activity of the immobilized invertase (from 1.0 mg/mL invertase solution at pH 5.5) were increased with increasing PANI contents of the composite fibers. The maximum amount of immobilized enzyme onto composite fibers containing 2.0% PANI was about 76.6 mg/g. The optimum pH for the free enzyme was observed at 5.0. On the other hand, immobilized invertase yielded a broad optimum PH profile between pH 5.0 and 7.0. Immobilized invertase exhibited 83% of its original activity even after two months storage at 4 degrees C while the free enzyme showed only 7% of its initial activity. (C) 2009 Elsevier Ltd. All rights reserved