Fikriye Tuncel Elmali

Synthesis in solvent-free conditions, characterization and biological activity of a new Schiff-base ligand and its Cu(II) complex

A new bis-imine Schiff base (N8O2 donor, LH2) has been synthesized by melt condensation of 3-amino-1,2,4-triazole with 1,5-bis(2′-formylphenyl)-1,5-dioksapentane in 2 : 1 molar ratio, in solvent and solvent-free conditions. The ligand has been characterized using FTIR, UV–Vis, 1H NMR, 13C NMR, mass spectra, elemental analysis, and thermal (TGA-DSC) techniques. A new complex of LH2 with Cu(II) has been synthesized in solvent and solvent-free conditions. FTIR, UV–Vis mass spectra, and thermal analysis (TGA-DSC) have been used to characterize the Cu(II) complex. Thermal degradation showed that the final products were black carbon and metallic copper. Distorted octahedral geometry has been observed around CuLH2Cl2 · LH2 and its Cu(II) complex have been screened for in vitro antifungal and antioxidant activities. Antioxidation was determined for their superoxide scavenging and reducing activities. The ligand and its Cu(II) complex have strong antifungal activity against Aspergillus niger. The compounds have significant superoxide anion radical scavenging activity and reducing power against various antioxidant systems in vitro.

Spectrophotometric method for the determination, validation, spectroscopic and thermal analysis of diphenhydramine in pharmaceutical preparation

A sensitive, simple and rapid spectrophotometric method was developed for the determination of diphenhydramine in pharmaceutical preparation. The method was based on the charge-transfer complex of the drug, as n-electron donor, with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ), as pi-acceptor. The formation of this complex was also confirmed by UV-vis, FTIR and (1)H NMR spectra techniques and thermal analysis. The proposed method was validated according to the ICH guidelines with respect to linearity, limit of detection, limit of quantification, accuracy, precision, recovery and robustness. The linearity range for concentrations of diphenhydramine was found to be 12.5-150 microg/mL with acceptable correlation coefficients. The detection and quantification limits were found to be 2.09 and 6.27 microg/mL, respectively. The proposed and references methods were applied to the determination of drug in syrup. This preparation were also analyzed with an reference method and statistical comparison by t- and F-tests revealed that there was no significant difference between the results of the two methods with respect to mean values and standard deviations at the 95% confidence level.

UV–Second Derivative Spectrophotometric and Colorimetric Methods for the Determination, Validation and Thermogravimetric Analysis of New Oral Antidiabetic Pioglitazone in Pure and Pharmaceutical Preparations

Abstract Three rapid, sensitive, and simple spectrophotometric methods have been developed for the determination of pioglitazone in pure and pharmaceutical preparations. For the first method, UV-spectrophotometry, standard solutions were measured at 270.2 nm. The first method was linear from 5.0–20.0 µgmL−1. The linearity was found to be 5.0–20.0 µgmL−1. For the second method, the distances between two extremum values (peak-to-peak amplitudes), 272.0 and 287.4 nm were measured in the second order derivative-spectra of standard solutions. Calibration curves were constructed by plotting d2 A/dλ2 values against concentrations, 2.0–12.0 µgmL−1 of pioglitazone standards in acetonitrile. The detection limits of pioglitazone were 0.10 and 0.16 µgmL−1 for UV and derivative spectrophotometric methods, respectively. The third method was based on the formation of an ion association complex with bromocresol green (BCG), bromocresol purple (BCP), bromophenol blue (BPB), and bromothymol blue (BTB). The assay was linear over the concentration range of 20.0–100.0 µgmL−1 for BCG, 10.0–100.0 µgmL−1 for BCP, 20.0–120.0 µgmL−1 for BPB, and 10.0–100.0 µgmL−1 for BTB. The detection limits of pioglitazone was found to be 0.14 µg mL−1 for BCG, 0.32 for BCP, 1.24 µgmL−1 for BPB, and 0.22 µgmL−1 for BTB. The thermal analysis of the pioglitazone was studied by Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC) techniques. Enthalpy change of pioglitazone was found to be 85.16 J/g. The proposed methods were validated according to the ICH guidelines (1996) with respect to specificity, linearity, limits of detection and quantification, accuracy, precision, and robustness. The results demonstrated that the procedure is accurate, precise, specific, and reproducible (percent relative standard deviation <2%), while being simple and less time consuming. The three proposed methods have been successfully applied to the assay of pioglitazone in pure and in pharmaceutical preparations. The results compared with those obtained by an ultraviolet spectrophotometric method using t and F tests.

Highly sensitive spectrophotometric methods for the determination, validation and thermogravimetric analysis of antiulcer drugs, nizatidine and ranitidine in pure and pharmaceutical preparations

Two sensitive, simple and rapid UV and second order derivative spectrophotometric methods were developed for the determination of nizatidine and ranitidine hydrochloride in pure form and pharmaceutical preparations. For the first method, UV spectrophotometic method, nizatidine was determined at 325 nm and ranitidine at 325.5 nm with detection limits of 0.07 and 0.04 μg/mL, respectively. For the second method, the distances between two extremum values (peak-to-peak amplitudes), 328/356.5 nm for nizatidine and 326/357 nm for ranitidine were measured in the second order derivative-spectra. The detection limits were found to be 0.02 μg/mL for nizatidine and 0.016 μg/mL for ranitidine, respectively. The thermal analysis of the two drugs was studied by Thermogravimetric Analysis-Differential Scanning Calorimetry (TGA-DSC) techniques. Enthalpy changes were obtained 121.9 and 124.15 J/g for nizatidine and ranitidine, respectively. The proposed method was successfully applied to the analysis of pharmaceutical preparations. The results were in good agreement with those obtained using the reference method; no significant difference were found in the accuracy and precision as revealed by the accepted values of t- and F-tests.

The Synthesis, Spectroscopic, Fluorescence, and Thermal Properties of a 1,10-phenanthroline Containing Derivative of Phenoxycyclotriphosphazene and its Ru(II) Complex

A new phenoxycyclotriphosphazene derivative ligand, 2-chloro -2-salicylideneimino-1,10-phenanthrolino-4,4,6,6-bis[spiro(2′,2″-dioksi-1′,1″-bifenil)]cyclotriphosp- hazane (CS-CP), has been synthesized from the reaction of 2,2-dichloro-4,4,6,6-bis[spiro(2′,2″-dioxybiphenyl)] cyclotriphosphazane and 5-salicylideneimino-1,10-phenanthroline and Ru(II) complex of this ligand has been prepared. The newly synthesized compounds have been verified by FTIR,1H NMR, 31P NMR, UV-vis., mass, and fluorescence spectra, together with elemental and thermal analysis.

Synthesis, characterization and biological activity of a new long-chain imine ligand and some transition metal complexes in solvent-free conditions

A new N-alkyl long-chain alkyl imine ligand (N-dodecyl-N1-dacanimine) has been synthesized by the reaction of dodecylamine (laurylamine) with decanal in molar 1 : 1 ratio and its Cu(I), Cu(II), Ni(II) and Co(II) complexes have been prepared under solvent-free conditions. The newly synthesized compounds have been verified by FTIR, UV-vis. and mass spectra. All of the compounds were tested for antimicrobial activity against Staphylococcus aureus ATCC 6538, meticillin resistant Staphylococcus aureus (MRSA) ATCC 33591, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Proteus mirabilis ATCC 14153 and the yeast, Candida albicans ATCC 10231. Among the compounds, the ligand was found the most active compound against all strains. The Cu(II)complex exhibited very strong antibacterial activity against bacteria except for Pseudomonas aeruginosa ATCC 1539, Proteus mirabilis ATCC 14153. Also, all compounds showed very strong antifungal effects against C. albicans ATCC 10231.

Synthesis of Pyridyloxycyclophosphazene and its Cu(I) Complex

A new pyridyloxycyclophosphazene, called 2,2′-bis[2-oxy-6-methylpyridine]-4,4,6,6-bis[spiro(2′,2”-dioxy-1,1′biphenyl)]cyclotriphosphazane (BB-CP) has been synthesized from the reaction of 2,2-dichloro-4,4,6,6-bis[spiro(2’,2”dioxybiphenyl)] cyclotriphosphazane (2Cl-CP) and 2-hydroxy-6-methylpyridine (HMP). The Cu(I) complex of this ligand has been prepared. The new ligand and Cu(I) complex were characterized by FT-IR, 1 H NMR, 31P NMR, UV-vis, mass spectra, elemental and thermal analyses.

Validated spectrophotometric method for the determination, spectroscopic characterization and thermal structural analysis of duloxetine with 1,2-naphthoquinone-4-sulphonate

A novel, selective, sensitive and simple spectrophotometric method was developed and validated for the determination of the antidepressant duloxetine hydrochloride in pharmaceutical preparation. The method was based on the reaction of duloxetine hydrochloride with 1,2-naphthoquinone-4-sulphonate (NQS) in alkaline media to yield orange colored product. The formation of this complex was also confirmed by UV-visible, FTIR, 1H NMR, Mass spectra techniques and thermal analysis. This method was validated for various parameters according to ICH guidelines. Beer’s law is obeyed in a range of 5.0–60 μg/mL at the maximum absorption wavelength of 480 nm. The detection limit is 0.99 μg/mL and the recovery rate is in a range of 98.10–99.57%. The proposed methods was validated and applied to the determination of duloxetine hydrochloride in pharmaceutical preparation. The results were statistically analyzed and compared to those of a reference UV spectrophotometric method.

2-[(E)-(1,10-Phenanthrolin-5-yl)imino­meth­yl]phenol methanol monosolvate

In the title multi-donor Schiff base compound, C19H13N3O·CH3OH, the dihedral angle between the mean planes of the phenanthroline and phenol rings is 59.3 (1)°. The Schiff base molecule is linked to the solvent molecule by an O—H⋯O hydrogen bond. In the crystal, the components are linked by O—H⋯N hydrogen bonds, weak O—H⋯N interactions and π–π stacking interactions [centroid–centroid distances = 3.701 (1) and 3.656 (1) Å].

Synthesis and Characterization of 5-Salicylideneimino-1, 10-phenanthroline and its Ni(II), Co(II) Complexes

As a multidonor ligand with phenanthroline and salicylaldimine functionalities on the same molecule, 5-salicylideneimino-l,10phenanthroline (LH) has been synthesized by the reaction of 5-amino-l,10phenanthroline with salicylaldehyde and its metal complexes with Ni(II) and Co(II) have been prepared. The structures of the ligand and its complexes have been characterized by elemental analyses, FTIR, Ή NMR, C NMR, LC-MS spectra, magnetic measurements and TGA-DSC-DTG techniques. The ligand, Ni(II) and Co(II) complexes have been studied potentiometrically. The metal to ligand ratio of the Ni(II) and Co(II) complexes was found to be 1:2. Protonation constants of LH2 which have been determined by potentiometric titration are log Ki=10.99, log K2 = 8.00.