Ayla Balaban Gündüzalp

Synthesis, characterization, electrochemical behavior, and antimicrobial activities of aromatic/heteroaromatic sulfonylhydrazone derivatives

The aromatic/heteroaromatic sulfonylhydrazone derivatives as indole-3-carboxaldehyde methanesulfonylhydrazone (1), indole-3-carboxaldehydeethanesulfonyl hydrazone (2), thiophene-2-carboxaldehydeethanesulfonylhydrazone (3), 2-hydroxybenzaldehydeethanesulfonyl hydrazone (4), 2-hydroxyacetophenoneethanesulfonylhydrazone (5) and 2-hydroxy-1-naphth aldehydeethane sulfonylhydrazone (6) were synthesized by the reaction of sulfonic acids with aromatic/heteroaromatic aldehydes and characterized by using elemental analysis, 1H–13C NMR, LC–MS and IR spectra. The electrochemical behavior of the sulfonylhydrazones in DMSO at glassy carbon electrode was investigated using cyclic voltammetry, controlled potential electrolysis and chronoamperometry techniques. The number of electrons transferred, diffusion coefficient and standard heterogeneous rate constants were determined using electrochemical methods. Antimicrobial activities of the compounds 1–6 were tested against some microorganisms. The biological activity screening showed that compound 6 exhibited better activity than the others. Structure–activity relationship analysis of the sulfonylhydrazone derivatives was performed to explain the trend of activity with molecular descriptors. The indicator descriptors for compound 6 having naphtyl ring are the most important descriptos that are sensitive both to the size and electrophility of the molecules.

New aromatic/heteroaromatic propanesulfonylhydrazone compounds: Synthesis, physical properties and inhibition studies against carbonic anhydrase II (CAII) enzyme

Some new aromatic/heteroaromatic propanesulfonylhydrazone derivatives (1-8) were synthesized and characterized by elemental analyses, FT-IR, (1)H NMR, (13)C NMR, LC/MS techniques. The geometry optimizations and spectral calculations were performed by using DFT/B3LYP/6-311G(d,p) basis set in Gaussian 09 program. The inhibition activities of the synthesized compounds on carbonic anhydrase II (CAII) isoenzyme have been investigated by comparing IC50 values. Acetazolamide (5-acetamido-1,3,4-thiadiazole-2-sulfonamide) AAZ, a clinically used in CAII inhibition has also been investigated as standard inhibitor. The best aromatic/heteroaromatic propanesulfonylhydrazone inhibitors of this isoform were o-aminobenzaldehydepropanesulfonylhydrazone (1) and thiophenecarboxyaldehyde propanesulfonylhydrazone (5) having the same IC50 (0.55 mM) value. The molecular descriptors for propanesulfonylhydrazones were obtained to develop structure activity relationship (SAR) model between experimental IC50 values and the molecular descriptors calculated by PM3-based SAR models in Hyperchem 8, respectively. The obtained models confirm the good carbonic anhydrase II (CAII) inhibition activity of the propanesulfonylhydrazone derivatives. The selected descriptors are sensitive both to the imine (CH=N) and NH2 groups that are responsible from higher activities of (1) and (5) in their series.

Copper(II) and zinc(II) complexes of thiophene/furan carboxamides: Synthesis, structure and properties

Cu(II) and Zn(II) complexes were synthesized from equimolar amounts of carboxamides; 1,8-bis(2-thiophenecarboxamido)-p-menthane (tkdam) and 1,8-bis(2-furancarboxamido)-p-menthane (furdam). The structure of the carboxamides were determined by elemental analysis; 1H NMR, 13C NMR, FT-IR and LC-MS spectra. The relative energies and the electronic properties (LUMO, HOMO, LUMO-HOMO gap) of the ligands were investigated theoretically by performing Semi-empirical molecular orbital theory PM3 method in Hyperchem 7 (Release). Carboxamide complexes having general formula as; monomeric, [ML]Cl2 and dimeric [Cu(tkdam)Cl]2Cl2 · 5H2O were synthesized and characterized by using element analysis; FT-IR, LC-MS spectra; magnetic susceptibility, molar conductivity and thermal (TGA/DTA curve) studies. It was found that the coordination number of the monomeric complexes is four whereas dimeric’s is six. The changes in the selected vibration bands in FT-IR indicate that, carboxamides behave as tetradentate ligands and coordinate to metal ions from acyl ring (through S/O) and amide carbonyl (C=O). Molar conductivity measurements indicate the 1: 2 ionic nature of the carboxamide complexes.

The synthesis, characterization and antibacterial activities of dinuclear Ni(II), Cu(II) and Fe(III) Schiff base complexes

Schiff base; N,N′-bis-(2-hydroxy-1-naphthaldimine)-1,3-diaminopropanol (napdapOH) reacts with metal chlorides to form dinuclear complexes of the type [M2L2] · nCl2 where M = Ni, Cu, Fe and n = 0, 1. Schiff base complexes were characterized by using FT-IR, LC-MS, magnetic moments and conductance measurements. Coordination was found to be through the phenolic oxygen atoms and azomethine nitrogen atoms. The electronic properties of the compounds were investigated theoretically by performing semiempirical molecular orbital theory PM3 method in Hyperchem 7 (Release). The antibacterial activities of the compounds were investigated against Escherichia coli ATCC 11230, Bacillus subtilis RSKK 244, Bacillus megaterium RSKK 5117, Salmonella enteritidis ATCC 13076, Staphylococcus aureus ATCC 25923 by using microdilution method.