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- MakaleAçık Erişim2026Scopus SJRQ1Comparative Study of Enzymatic and Oxidative Polymerization of a Benzothiazole-Based Schiff Base and Its Antibacterial Properties
Kaya, İsmet; Solmaz, Adnan; Abuawad, Mohammed Majed Shible
In this study, the Schiff base 1-(((6-nitrobenzo[d]thiazol-2-yl) imino)methyl)naphthalen-2-ol (NBTIMN) was synthesized and subsequently polymerized by two different methods. Oxidative polymerization in the presence of organic (o-(NBTIMN)-O) and aqueous alkaline media (o-(NBTIMN)-A) was one of the techniques. The other was enzyme-catalyzed oxidative polymerization (o-(NBTIMN)-E), which was conducted at room temperature with hydrogen peroxide and the enzyme horse radish peroxidase (HRP). The structures of the obtained oligomers were characterized using FT-IR, 1H-13C-NMR, UV–Vis, CV, and GPC analyses, and their electrochemical and optical band gaps were determined as 2.68, 2.66, and 2.49 eV, and 3.08, 2.90, and 3.07 eV for o-(NBTIMN)-O, o-(NBTIMN)-A, and o-(NBTIMN)-E, respectively. Thermal analyses demonstrated that the o-(NBTIMN)-O and o-(NBTIMN)-A derivatives exhibited enhanced thermal stability, characterized by higher decomposition temperatures and LOI values. SEM analyses revealed distinct differences in surface morphologies depending on the polymerization conditions. Antibacterial assays showed that o-(NBTIMN)-O exhibited the strongest broad-spectrum inhibition, whereas NBTIMN displayed pronounced activity against S. aureus. In contrast, o-(NBTIMN)-A and o-(NBTIMN)-E were found to be inactive. These results highlight the critical influence of polymerization conditions on both the physicochemical characteristics and the biological activities of the synthesized structures. Importantly, the comparative design of enzymatic and chemical polymerization demonstrates the potential for environmentally friendly synthesis strategies. The distinct electrochemical and thermal properties suggest applicability in electronics and sensor-related fields, while the pronounced antibacterial activity of o-(NBTIMN)-O holds promise for biomedical and antimicrobial applications.
- MakaleYalnız künye2026Scopus SJRQ1Oxidative Polycondensation of Pyrazolone-Based Schiff Bases: Synthesis, Structural Characterization, Thermal and Electrical Properties
Solmaz, Adnan; Çakmak, Reşit; Kaya, İsmet
Schiff base derivatives, namely 3-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1-phenyl-1-pyrazole-5-one (3-APPHNA) and 4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3-one (4-APPHNA), were synthesized via the condensation reaction of 3-amino-1-phenyl-2-pyrazolin-5-one (3-APP) and 4-amino-2,3-dimethyl-1-phenyl-3-pyrazolin-5-one, (4-APP) with 2-hydroxynaphthaldehyde (2-HNA) in ethanol. Synthesized monomers were then converted into their oligomeric derivatives via oxidative polycondensation carried out using NaOCl. The structural, thermal, optical, electrochemical, and morphological properties of the obtained monomers were comprehensively characterized using fourier transform infrared (FT-IR), proton nuclear magnetic resonance (1H-NMR), carbon-13 nuclear magnetic resonance (13C-NMR), ultraviolet-visible spectrophotometer (UV–vis), thermogravimetry-derivative thermogravimetry (TG-DTG), and cyclic voltammetric analyses. Spectroscopic studies confirmed the successful synthesis of Schiff bases and the presence of stable azomethine bonds. Molecular weight, glass transition temperature, and surface morphologies of oligomers were determined by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and field emission scanning electron microscope (FE-SEM) measurements, respectively. The Mn values of oligo(3-APPHNA) and oligo(4-APPHNA) were found to be 3400 and 2900 Da, respectively. The results revealed an oxidative oligomerization process yielding relatively narrow molecular weight distributions. Oligo(4-APPHNA) has shown more pronounced semiconductor properties compared to other oligomers, considering its 2.30 eV optical band gap and frequency-dependent electrical behavior. Additionally, dielectric measurements showed that oligo(4-APPHNA) exhibited higher dielectric constant, dielectric loss, and AC conductivity values throughout the investigated frequency range. These findings suggest that the synthesized oligomers are promising candidate materials for future optoelectronic and semiconductor applications, but further research at the device level is needed.
- MakaleAçık Erişim2025Scopus SJRQ2Synthesis and characterization of oligomers contain phenylhydrazyne unit via oxidative polycondensation: Adsorption studies, kinetic modeling and validation methods
Bayır, Erdal; Solmaz, Adnan; Kaya, İsmet; Yağmur, Hatice Karaer
In this study, 4-((2-phenylhydrazono)methyl)benzene-1,2-diol (4-PHBD) Schiff base was obtained from the condensation reaction between 3,4-dihydroxybenzaldehyde (3,4-DHBA) and phenylhydrazine (PH). The obtained Schiff base (4-PHBD) was polymerized using H2O2, NaOCl, and O2 oxidants in an aqueous basic medium (10 % KOH) and 4-PHBD was converted to o-(4-PHBD)-P (by H2O2 oxidant), o-(4-PHBD)-H (by NaOCl oxidant) and o-(4-PHBD)-O (by O2 oxidant). The structures of Schiff base and oligomers were characterized with FT-IR, NMR, SEM, TGA, UV-Vis, CV and GPC measurements. The Cyclic Voltammetry and UV-Vis measurements were used to ascertain the compounds' optical (Eg) and electrochemical (Eg’) band gaps, respectively. The Eg values of o-(4-PHBD)-P, o-(4-PHBD)-O and o-(4-PHBD)-H were found be 2.99, 2.63 and 3.26 eV, respectively. o-(4-PHBD)-O was used as an adsorbent in the removal of methylene green (MG) from an aqueous solution. The obtained data were applied to pseudo-first order and pseudo-second order kinetic models. It was determined that the adsorption process obeyed the pseudo first order kinetic model. The kinetic model was validated with R2, RMSE, SSE, SD, Δqe (%), MSE and ARE validation methods. The activation energy (Ea) was calculated as 7.31 kJ mol−1 using the Arrhenius equation. It was determined that the adsorption of MG on o-(4-PHBD)-O was physical adsorption.
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