Oxidative Polycondensation Reaction Research Articles

Effect of ozonation conditions on transformation of the components of catalytic light gasoil

The results of comprehensive studies of transformation of hydrocarbons in light catalytic gasoil (LCG) by ozone in different ozonation conditions are reported. It was found that low-temperature oxidative cracking and oxidative polycondensation reactions take place as a result of electrophilic 1,3-addition of ozone to the components of the LCG. The flash point of the samples decreased, and the concentration of adsorption resins increased. Olefins have the highest activity in interaction with ozone. The optimum conditions of ozonation of LCG were selected.

SYNTHESIS, CHARACTERIZATION, THERMAL DEGRADATION AND ELECTRICAL CONDUCTIVITY OF OLIGO[2-(2-HYDROXYPHENYLIMINOMETHYL-BENZYLIDENE)AMINOPHENOL] AND OLIGOMER-METAL COMPLEXES

The oxidative polycondensation reaction conditions of 2-[(2-hydroxyphenyliminomethylbenzylidene)amino-phenol] (2-HPIMBAP) has been accomplished by using air O2 and NaOCl oxidants in an aqueous alkaline medium between 50–90°C. The optimum reaction conditions of the oxidative polycondensation and the main parameters of the process were established. At the optimum reaction conditions, yield of the products were found to be 67.72% and 61.49% for air O2 and NaOCl oxidants respectively. The structures of the monomer and oligomer were confirmed by FT-IR, UV-Vis, 1H-NMR and 13C-NMR and elemental analysis. Also, TGA-DTA, SEC techniques and solubility tests were applied for characterization. 1H-NMR and 13C-NMR data show that the polymerization proceeded by the C-C and C-O-C coupling systems of ortho and para positions and oxyphenylene according to -OH group of 2-HPIMBAP. The number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of oligo[2-(2-hydroxyphenylim...

The oxidative polycondensation of 2-[(4-pyridilmethylene)-imino]phenol by molecular O2 in alkaline medium: Synthesis and characterization

The polymer of 2-[(4-pyridilmethylene)-imino] phenol (2-PIP) has been formed from the oxidative polycondensation (OP) reaction by using molecular O2 as the oxidant in an aqueous alkaline medium between 60–90 °C. The optimum reaction conditions and the main parameters of the process were determined. The yield of polymer was found as 50.1%. The structures of synthesized monomer and polymer were confirmed by FT-IR, UV-vis, 1H-13C-NMR and elemental analysis. The characterization was made by TGA-DTA, size exclusion chromatography (SEC) and solubility tests. The 1H-13C-NMR data shows that the polymerization proceeded with C-C and C-O-C coupling system of ortho and para positions and oxyphenylene according to –OH group of 2-PIP. The molecular weight distribution values of the product were determined from SEC measurement. The number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of poly-2-[(4-pyridilmethylene)-imino]phenol (poly-2-PIP) were found to be 11350, 12600 g.mol-1 and 1.110, respectively. According to thermo gravimetric analysis (TGA), the carbon residues of 2-PIP and poly-2-PIP were found to be 18.17% and 45.10%, respectively, at 1000 °C.

Synthesis and characterization of thermally stable Schiff base polymers and their copper(II), cobalt(II) and nickel(II) complexes

In this study, the Schiff base monomers [(M 1; N, N′- p-phenylenebis(salicylideneimine)) and ethylenediamine (M 2; N, N′- p-ethylenebis(salicylideneimine))] were synthesized by the condensation reaction between p-phenylenediamine and aromatic aldehydes. The Schiff base polymers (SBPs) having double azomethine groups were prepared by oxidative polycondensation (OP) reaction of monomers in aqueous alkaline medium with NaOCl [P 1; poly-( N, N′- p-phenylenebis(salicylideneimine)) and P 2; poly-( N, N′- p-ethylenebis(salicylideneimine))] as the oxidant at 90 °C. Average molecular weights of SBP were determined by gel permeation chromatography (GPC). Metal complexes of the SBP were synthesized by the reaction of polymers and metal salts. The monomers and SBP were characterized by elemental analyses, GPC, thermogravimetric analyses, UV–Vis, FT-IR, 1H and 13C NMR spectroscopic studies. Also the new Cu(II), Ni(II) and Co(II) complexes of SBP were prepared and characterized by elemental analyses, UV–Vis, FT-IR, atomic absorption spectroscopy (AAS), thermogravimetric analyses and magnetic susceptibility measurements. The results suggested that the SBP and metal ions in 1:1 molar ratio produced binuclear complexes with oxygen and nitrogen donor atoms. All synthesized complexes have dimeric structures by the polymeric ligand units. The weight losses of P 1–Cu, P 2–Ni and P 1–Co complexes were found as 57%, 60% and 61%, at 900 °C, respectively. Thermal stability of P 1 complexes is higher than that of P 2 complexes. Magnetic moment studies showed that all complexes have various configurations. The metal ion uptake studies were done by batch technique. The polymer P 1 was determined to be more effective in removing Cu(II) ions than the P 2 polymer in batch technique.

Synthesis, characterization, conductivity, band gap and thermal analysis of poly-2-[(4-mercaptophenyl) imino methyl] phenol and some of its polymer–metal complexes

The oxidative polycondensation reaction conditions of 2-[(4-mercaptophenyl) imino methyl] phenol (4-MPIMP) was studied in an aqueous alkaline medium between 30 and 90 °C by using oxidants such as air O 2, NaOCl and H 2O 2. Polymer–metal complex compounds were synthesized from the reactions of poly-2-[(4-mercaptophenyl) imino methyl] phenol (P-4-MPIMP) with Cr 3+, Co 2+, Ni 2+, Cu 2+, Mn 2+, Zn 2+, Pb 2+, Cd 2+ and Zr 4+ ions. The structures of these monomer and polymer were identified from UV–vis, FT-IR, 1H NMR, 13C NMR and elemental analysis. While thermal analysis of P-4-MPIMP and polymer–metal complexes were made by TGA–DTA, the number-average molecular weight ( M n), weight-average molecular weight ( M w) and polydispersity index (PDI) values of this polymer were determined by size exclusion chromatography (SEC). According to TG–DTA analyses, P-4-MPIMP–Cu was found to be higher stable than other synthesized polymer and polymer–metal complexes. While conductivity measurements of polymer and polymer–metal complexes were done by electrometer using four point probe techniques, electrochemical and optical band gap values of 4-MPIMP, P-4-MPIMP and polymer–metal complexes were determined by using cyclic voltammetry and UV–vis measurements. Conductivity and band gap values show that this polymer and polymer–metal complexes are a typical semiconductor.

Synthesis, characterization, thermal stability, conductivity, and band gap of a new aromatic polyether containing an azomethine as a side

AbstractIn this study, the oxidative polycondensation reaction conditions of 4‐[(4‐methylphenyl)iminomethyl]phenol (4‐MPIMP) were studied by using oxidants such as air O2, H2O2, and NaOCl in an aqueous alkaline medium between 50 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FTIR, UV–vis, 1H–13C‐NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(4‐methylphenyl)iminomethyl]phenol (P‐4‐MPIMP) was found to be 28% for air O2 oxidant, 42% for H2O2 oxidant, and 62% for NaOCl oxidant. According to the SEC analysis, the number–average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index values of P‐4‐MPIMP were found to be 4400 g mol−1, 5100 g mol−1, and 1.159, using H2O2, and 4650 g mol−1, 5200 g mol−1, and 1.118, using air O2, and 5100 g mol−1, 5900 g mol−1, and 1.157, using NaOCl, respectively. According to TG analysis, the weight losses of 4‐MPIMP and P‐4‐MPIMP were found to be 85.37% and 72.19% at 1000°C, respectively. P‐4‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐4‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels and electrochemical energy gaps (E) of 4‐MPIMP and P‐4‐MPIMP were found to be −5.76, −5.19; −3.00, −3.24; 2.76 and 1.95 eV, respectively. According to UV–vis measurements, optical band gaps (Eg) of 4‐MPIMP and P‐4‐MPIMP were found to be 3.34 and 2.82 eV, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

Synthesis, characterization, and thermal stability of azomethine oligomer and its metal complexes

AbstractThe oxidative polycondensation reaction conditions of N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (2‐HNMU) has been accomplished using NaOCl, H2O2, and air O2 oxidants in an aqueous alkaline medium. The structures of the obtained monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13C NMR, and elemental analysis. The characterization was made by TG‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo‐N,N′‐bis[(2‐hydroxy‐1‐naphthyl)methylene]urea (O‐2‐HNMU) was found to be 95% (for air O2 oxidant), 51% (for H2O2 oxidant), 96% (for NaOCl oxidant). According to the SEC analysis, the number‐average molecular weight (Mn), weight‐average molecular weight (Mw), and polydispersity index values of O‐2‐HNMU was found to be 1036, 1225 g/mol, and 1.182, respectively, using H2O2, and 765, 1080 g/mol, and 1.412, respectively, using air O2, and 857, 1105 g/mol, and 1.289, respectively, using NaOCl. TG‐DTA analyses showed that O‐2‐HNMU was more stable than 2‐HNMU. According to TG analyses, the carbonaceous residue of 2‐HNMU and O‐2‐HNMU was found to be 0.49% and 2.11% at 1000°C, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Synthesis, characterization, thermal analysis, and band gap of oligo‐2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol

AbstractThe oxidative polycondensation reaction conditions of 2‐methoxy‐6‐[(4‐methylphenyl)imino]methylphenol (2M‐4‐MPIMP) by using oxidants such as air O2, H2O2 and NaOCl were studied in an aqueous alkaline medium between 30 and 90°C. The structures of synthesized monomer and oligomer were confirmed by FTIR, UV–vis, 1H NMR, 13CNMR, and elemental analysis. The characterization was made by TG–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of oligo (O)‐2M‐4‐MPIMP was 68% for air O2 oxidant, 68% for H2O2 oxidant, and 82% for NaOCl oxidant. According to the SEC analysis, the number– average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index (PDI) values of O‐2M‐4‐MPIMP were found to be 695, 1000 g mol−1 and 1.439, using air O2, and 670, 795 g mol−1 and 1.187, using NaOCl, and 645, 790 g mol−1 and 1.225, using H2O2, respectively. TG–DTA analyses were shown to be stable of O‐2M‐4‐MPIMP against thermal decomposition. The weight losses of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were found to be 98.46% and 89.54% at 1000°C, respectively. Also, electrical conductivity of the O‐2M‐4‐MPIMP was measured, showing that the polymer is typical semiconductor. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of monomer and oligomer were determined from the onset potentials for n‐doping and p‐doping, respectively. Optical energy gaps (Eg) of 2M‐4‐MPIMP and O‐2M‐4‐MPIMP were calculated from UV–vis measurements. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

New soluble azophenol polymers prepared by oxidative polycondensation

New azophenol polymers (P1, P2 and P3) 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, 1H NMR and 13C 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, P2 and P3 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 (P1), 263, 609 (P2) and 100, 809 °C (P3), 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. Copyright © 2007 Society of Chemical Industry

SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL PROPERTIES OF 4-[(4-HYDROXYBENZYLIDENE) AMINO] PHENOL AND ITS POLYMER

The oxidative polycondensation reaction conditions of 4-[(4-hydroxybenzylidene) amino] phenol (4-HBAP) were studied with H2O2, air oxygen and NaOCl in an aqueous alkaline medium between 50 and 90°C. The structures of the obtained monomer and polymer were confirmed by FT-IR, UV-Vis, 1H- and 13C-NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of poly[4-(4-hydroxybenzylidene amino) phenol] (P-4-HBAP) was found to be 48.3% (for H2O2 oxidant), 80.5% (for air O2 oxidant) and 86.4% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of P-4-HBAP was found to be 8950, 10970 g mol-1 and 1.225, respectively, using H2O2; and 11610, 15190 g mol-1 and 1.308 respectively, using air O2 and 7900, 9610 g mol-1 and 1.216, respectively, using NaOCl. According to TG-DTA analyses, P-4-HBAP was more stable than 4-HBAP against thermal decomposition. The weight loss of P-4-HBAP was found to be 49.27% at 1000°C. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) values calculated from electrochemical measurement. Electrochemical energy gaps (Eg′) of 4-HBAP and P-4-HBAP were found to be -5.46, -5.28; -2.26, -2.67; 3.20 and 2.61 eV, respectively. According to UV-Vis measurements, optical band gap (Eg) of 4-HBAP and P-4-HBAP were found to be 3.34 and 3.01 eV, respectively. Also, antimicrobial activities of 4-HBAP and P-4-HBAP were examined against selected some bacteria. The electrical conductivity of the polymer was measured after doping with iodine.

Conductivity and band gap of oligo-2-[(4-fluorophenyl) imino methylene] phenol and some of its oligomer-metal complexes

Schiff base oligomer of 2-[(4-fluorophenyl) imino methylene] phenol (FPIMP) was synthesized via oxidative polycondensation reaction in an alkaline medium. Oligomer-metal complex compounds were synthesized from the reactions of oligo-2-[(4-fluorophenyl) imino methylene] phenol (OFPIMP) with Co +2, Ni +2 and Cu +2 ions. The synthesis was achieved by oxidative coupling based on air oxygen as an oxidant. While synthesized Schiff base oligomer was soluble in most common organic solvents, its metal complexes were only soluble in dimethylsulfoxide. Electrochemical HOMO and LUMO band gap ( E g) of monomer, oligomer and its metal complexes were calculated from oxidation and reduction onset values. According to cyclic voltammetry (CV) and UV–vis measurements, electrochemical energy gaps ( E g ′ ) and optical band gap ( E g) values of monomer and oligomer were found to be 3.26 and 3.10; 3.15 and 2.96 eV, respectively. Conductivity measurements of doped and undoped Schiff base oligomer and its metal complexes were carried out by electrometer at a room temperature and atmospheric pressure and were calculated from four-point probe technique. When iodine was used as doping agent, conductivity of this oligomer and its metal complexes were observed to be increased.

Synthesis, characterization, and thermal degradation of oligo‐2‐(morpholinoiminomethyl)phenol and its Pb(II) complex compound

AbstractThe oxidative polycondensation reaction conditions of 2‐(morpholinoiminomethyl)phenol were studied with H2O2, air O2, and sodium hypochloride (NaOCl) oxidants in an aqueous alkaline medium between 40 and 90°C. The structure of oligo‐2‐(morpholinoiminomethyl)phenol was characterized with 1H‐ and 13C‐NMR, Fourier transform infrared, ultraviolet–visible, size exclusion chromatography, and elemental analysis techniques. Under the optimum reaction conditions, the yield of oligo‐2‐(morpholinoiminomethyl)phenol was 28% for the H2O2 oxidant, 12% for the air O2 oxidant, and 58% for the NaOCl oxidant. According to the size exclusion chromatography analysis, the number‐average molecular weight, weight‐average molecular weight, and polydispersity index of oligo‐2‐(morpholinoiminomethyl)phenol were 2420 g/mol, 2740 g/mol, and 1.187 with H2O2, 1425 g/mol, 2060 g/mol, and 1.446 with air O2, and 1309 g/mol, 1401 g/mol, and 1.070 with NaOCl, respectively. Thermogravimetry/dynamic thermal analysis showed that the oligo‐2‐(morpholinoiminomethyl)phenol–lead complex compound was more stable than 2‐(morpholinoiminomethyl)phenol and oligo‐2‐(morpholinoiminomethyl)phenol against thermal degradation. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:3795–3804, 2006

Synthesis, characterization, and antimicrobial properties of oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol

AbstractThe oxidative polycondensation reaction conditions of 4‐[(pyridine‐3‐yl‐methylene) amino]phenol (4‐PMAP) were studied using H2O2, atmospheric O2, and NaOCl oxidants in an aqueous alkaline medium between 30°C and 90°C. Synthesized oligo‐4‐[(pyridine‐3‐yl‐methylene) amino] phenol (O‐4‐PMAP) was characterized by 1H‐, 13C NMR, FTIR, UV–vis, size exclusion chromatography (SEC), and elemental analysis techniques. The yield of O‐4‐PMAP was found to be 32% (for H2O2 oxidant), 68% (for atmospheric O2 oxidant), and 82% (for NaOCl oxidant). According to the SEC analysis, the number–average molecular weight, weight–average molecular weight, and polydispersity index values of O‐4‐PMAP was found to be 5767, 6646 g mol−1, and 1.152, respectively, using H2O2, and 4540, 5139 g mol−1, and 1.132, respectively, using atmospheric O2, and 9037, 9235 g mol−1, and 1.022, using NaOCl, respectively. According to TG and DSC analyses, O‐4‐PMAP was more stable than 4‐PMAP against thermal decomposition. The weight loss of O‐4‐PMAP was found to be 94.80% at 1000°C. Also, antimicrobial activities of the oligomer were tested against B. cereus, L. monocytogenes, B. megaterium, B. subtilis, E. coli, Str. thermophilus, M. smegmatis, B. brevis, E. aeroginesa, P. vulgaris, M. luteus, S. aureus, and B. jeoreseens. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3327–3333, 2006

Synthesis, characterization, conductivity and thermal degradation of oligo-2-[(4-morpholin-4-yl-phenyl)imino]methylphenol and its oligomer–metal complex compounds

Schiff base oligomer of 2-[(4-morpholin-4-yl-phenyl)imino]methylphenol (2-MPIMP) was synthesized via oxidative polycondensation reaction by using air O 2 and NaOCl oxidants in an alkaline medium between 40 and 90 °C. The structure of oligo-2-[(4-morpholin-4-yl-phenyl)imino]methylphenol (O-2-MPIMP) was characterized by using 1H, 13C NMR, FT-IR, UV–vis, size exclusion chromatography (SEC) and elemental analysis techniques. At the optimum reaction conditions, the yield of O-2-MPIMP was found to be 73% (for air O 2 oxidant) and 97% (for NaOCl oxidant). According to the SEC measurements, the number-average molecular weight ( M n), weight-average molecular weight ( M w) and polydispersity index (PDI) values of O-2-MPIMP was found to be 1725, 2030 mol −1 and 1.177, respectively, using air O 2 and 1345, 1490 g mol −1 and 1.108, using NaOCl, respectively. Oligomer–metal complex compounds were synthesized from the reactions of O-2-MPIMP with Cu 2+, Co 2+, Cd 2+, Zn 2+, Pb 2+ and Zr 4+ ions. Electrochemical the highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical energy gaps ( E ′ g ) for 2-MPIMP and O-2-MPIMP were found to be between −5.85 and −5.82, −2.63 and −2.87, 3.22 and 2.95 eV. Also, conductivity values of oligomer and oligomer–metal complex compounds were determined from their solid conductivity measurements. Conductivity measurements of doped and undoped Schiff base oligomer and its metal complexes were carried out by electrometer at room temperature and atmospheric pressure and were calculated from four-point probe technique. When iodine was used as doping agent, conductivity of this oligomer and its metal complexes were observed to be increased.

The Oxidative Polycondensation of 4-[(Phenylimino) Methyl] Phenol Using NaOCl, Air Oxygen, and H2O2 at Alkaline and Neutral Medium: Synthesis and Characterization

In this study, the oxidative polycondensation reaction conditions of 4-[(phenylimino) methyl] phenol (4-PIMP) with air oxygen, H2O2, and NaOCl oxidants in aqueous alkaline and neutral medium between 50° and 90°C were examined. 4-PIMP and its condensation product, oligo-4-[(phenylimino) methyl] phenol (O-4-PIMP), were characterized by 1H-13C-NMR, FT-IR, UV-vis techniques, and elemental analysis. At the optimum reaction conditions, the yield of oligo-4-[(phenylimino) methyl] phenol was found to be 73% for NaOCl, 65% for air O2, and 70% for H2O2. According to size exclusion chromatography (SEC) analyses, the number-average molecular weight (Mn), weight-average molecular weight (Mw), and polydispersity index (PDI) values of O-4-PIMP were 5268, 10320 g mol−1, and 1.959, respectively, using air O2; 8215, 17789 g mol−1, and 2.165, respectively, using NaOCl; and 4800, 5260 g mol−1, and 1.096, respectively, using H2O2. The carbon residues for 4-PIMP and O-4-PIMP were found to be 42.4% and 53.4%, respectively, at 1000°C by using TG-DTA analyses.

Synthesis, characterization, thermal stability, conductivity and band gap of oligo-4-[(2-hydroxybenzylidene)amino]benzoic acid

In this study, the oxidative polycondensation reaction conditions of 4-[(2-hydroxybenzylidene)amino]benzoic acid (4-HBAB) by using oxidants such as air O 2, H 2O 2 and NaOCl were studied in an aqueous alkaline medium between 40 and 90 °C. The structures of the synthesized monomer and oligomer were confirmed by FT-IR, UV–vis, NMR and elemental analysis. The characterization was made by TG-DTA, size exclusion chromatography (SEC) and solubility tests. At the optimum reaction conditions, the yield of oligo-4-[(2-hydroxybenzylidene)amino]benzoic acid (O-4-HBAB) was found to be 68% (for air O 2 oxidant), 70% (for air H 2O 2 oxidant) 53% (for NaOCl oxidant). According to the SEC analysis, the number-average molecular weight ( M n), weight-average molecular weight ( M w) and polydispersity index (PDI) values of O-4-HBAB were found to be 932, 1469 g mol −1 and 1.576, using H 2O 2, and 1895, 2560 g mol −1 and 1.354, using air O 2 and 2320, 3015 g mol −1 and 1.300, using NaOCl, respectively. According to TG analysis, the weight losses of 4-HBAB and O-4-HBAB were found to be 96.86% and 73.10% at 1000 °C, respectively. O-4-HBAB was shown higher stability against thermal decomposition. Also, electrical conductivity of the O-4-HBAB was measured, showing that the polymer is a typical semiconductor. Electrochemical HOMO, LUMO and energy gaps ( E g) of 4-HBAB and O-4-HBAB were found to be −6.28, −6.36; −2.39, −2.64; 3.89 and 3.72 eV, respectively. According to UV–vis measurements, optical band gap ( E g) of 4-HBAB and O-4-HBAB were found to be 3.23 and 3.09 eV, respectively.

Conductivity and band gap of oligo-2-[(4-chlorophenyl) imino methylene] phenol and its oligomer–metal complexes

Schiff base oligomer of 2-[(4-chlorophenyl) imino methylene] phenol (CPIMP) was synthesized via oxidative polycondensation reaction in an alkaline medium. Oligomer–metal complex compounds were synthesized from the reactions of oligo-2-[(4-chlorophenyl) imino methylene] phenol (OCPIMP) with Co+2, Ni+2 and Cu+2 ions. The synthesis was achieved by oxidative coupling based on air oxygen as an oxidant. While synthesized Schiff base oligomer was soluble in most common organic solvents, its metal complexes were only soluble in dimethylsulfoxide. Electrochemical HOMO and LUMO band gap (Eg) of this oligomer and its metal complexes were found to be between −6.17, −5.28 and −2.91, −3.26 and 3.29 and 2.02 eV, respectively. However optical band gap (Eg) of this oligomer and its metal complexes were calculated from their absorption edges and were found between 2.26 and 3.18 eV. Conductivity measurements of doped and undoped Schiff base oligomer and its metal complexes were carried out by electrometer at room temperature and atmospheric pressure and were calculated from four-point probe technique. When iodine was used as doping agent, conductivity of this oligomer and its metal complexes were observed to be increased.

A new soluble Schiff base polymer with a double azomethine group synthesized by oxidative polycondensation

A Schiff base monomer was synthesized by the condensation reaction between salicylaldehyde and ethylenediamine. The Schiff base polymer, with a double azomethine group, was prepared by oxidative polycondensation (OP) reaction of monomer in aqueous alkaline medium with NaOCl as an oxidant at 90°C. The monomer and polymer were characterized by UV-Vis, FT-IR, 1H- and 13C-NMR spectroscopic studies, which revealed that the polymer synthesized by OP is composed of oxyphenylene (55%) and phenylene (45%) units. The polymer was soluble in aqueous alkaline, THF, DMF and DMSO. The thermal properties of monomer and polymer were evaluated by differential thermal analysis (DTA) and thermogravimetric (TG) analyses. According to TG, the 5% and 50% weight loss temperatures of the polymer were 200°C and 800°C, respectively.

Synthesis, Characterization, and Thermal Degradation of Oligo-2-[(4-Chlorophenyl) Imino Methylene] Phenol and Its Oligomer-Metal Complexes

The oxidative polycondensation reaction conditions of 2-[(4-chlorophenyl) imino methylene] phenol (CPIMP) were studied by air O2 and NaOCl oxidants at various temperatures and times. Optimum reaction conditions of air O2 and NaOCl were determined for CPIMP. Oligo-2-[(4-chlorophenyl) imino methylene] phenol (OCPIMP) was synthesized from the oxidative polycondensation of CPIMP with air O2 and NaOCl in alkaline medium between 50 and 90°C. The number-average molecular weight (Mn) weight-average molecular weight (Mw) and polydispersity index (PDI) values of OCPIMP were found to be 470 g mol−1, 895 g mol−1, and 1.90, using NaOCl, and 455 g mol−1, 765 g mol−1, and 1.68, using air O2, respectively. At the optimum reaction conditions, the yield of OCPIMP was found to be 62.80% (for air O2 oxidant) and 87.50% (for NaOCl oxidant). The OCPIMP was characterized by 1H-NMR, FT-IR, UV-Vis and elemental analysis. The thermogravimetric (TGA)-DTA analyses were shown to be stable of OCPIMP and its oligomer metal complexes (such as Co+2, Ni+2, and Cu+2) against thermo-oxidative decomposition. The weight loss of OCPIMP and its oligomer metal complexes (such as Co+2, Ni+2, and Cu+2) were found to be 98%, 85%, 80%, and 82%, respectively, at 1000°C.

The Oxidative Polycondensation of Benzylidene-4′-hydroxyanilene using Air O2, NaOCl and H2O2: Synthesis and Characterization

In this work, the oxidative polycondensation reaction conditions of benzylidene-4′-hydroxyanilene (B-4′-HA) were studied using oxidants such as air O2, H2O2 and NaOCl in an aqueous alkaline medium between 40 and 95 ○C. Oligo-benzylidene-4′-hydroxyanilene was characterized by 1H-NMR, FT-IR, UV-Vis, size exclusion chromatography (SEC) and elemental analysis techniques. The solubility of oligomer using organic solvents such as DMF, THF, DMSO, methanol, ethanol, CHCl3, CCl4, toluene, acetonitrile, ethyl acetate was investigated. According to air O2 oxidant (flow rate 8.5 L/h), the conversion of B-4′-HA was 82.0% in optimum conditions such as [B-4′-HA]0=[KOH]0=0.1015 mol/L at 50 ○C for 25 h. According to the SEC analysis, the number-average molecular weight (Mn), weight-average molecular weight (Mw) and polydispersity index (PDI) values of O-B-4′-HA were found to be 1852 g mol−1, 3101 g mol−1 and 1.675; 2123 g mol−1, 4073 g mol−1 and 1.919; 2155 g mol−1, 4164 g mol−1 and 1.932, using air oxygen, NaOCl and H2O2 oxidants, respectively. Also, Thermo gravimetric analysis (TGA) showed oligo-benzylidene-4′-hydroxyanilene to be unstable against thermo-oxidative decomposition. The weight loss of O-B-4′-HA was found to be 95.87% at 1000 ○C.