Tautomeric conversion, vibrational spectra, and density functional studies on peripheral sulfur derivatives of benzothiazole and benzothiazoline isomers.

The room temperature structural (tautomerism, dimerization, conformational preference, geometry parameters) and vibrational spectral (IR and Raman) analyses have been performed on benzothiazoline (benzothiazoline-2-thione, 3-methyl-benzothiazoline-2-thione) and benzothiazole [2-mercaptobenzothiazole, 2-methylthiobenzothiazole, and bis(benzothiazole-2-ylthio)ethane] derivatives at the B3LYP/6-311++G(∗∗) level of theory. Although the keto to enol transition barriers are too high over the most stable benzothiazoline isomers, vibrational spectral analyses reveal some major bands of benzothiazole isomers in the present room temperature experimental FT-IR and FT-Raman specta. Therefore, benzothiazole isomers exist at rare amounts in the powdered samples that are mainly composed of benzothiazoline isomers. The benzothiazole isomers have two stable conformations due to the orientation of their SH and SCH3 moieties. The energetic and vibrational spectral analyses suggest that the benzothiazoline-2-thione molecules can be stabilized further through the NH⋯S intermolecular hydrogen bonds in solid phase. All observed fundamental vibrational bands of the molecules have been assigned based on the calculated mode frequencies and IR/Raman intensities. The mode assignments have been expressed in terms of internal coordinates and their percent potential energy distributions. The effects of substitution at the nitrogen and peripheral sulfur atoms have been analyzed for the geometries and vibrational bands of the molecules.

Synthesis, Raman, FT-IR, NMR spectroscopic characterization, antimicrobial activity, cytotoxicity and DNA binding of new mixed aza-oxo-thia macrocyclic compounds.

Series of new mixed aza-oxo-thia macrocyclic ligands 1,9(2,6)-ditriazina-2,8,10,16-tetraaza-3,7,11,15-tetraoxo-5,13-dithia-cyclohexadecaphan-1(4),9(4)-diphenyl (L(1)); 1,10(2,6)-ditri azina-2,9,11,18-tetraaza-3,8,12,17-tetraoxo-5,6,14,15-tetrathia-cyclooctadecaphan-1(4),10(4)-diphenyl (L(2)); 1,11(2,6)-ditriazina-2,10,12,20-tetraaza-3,9,13,19-tetraoxo-6,16-dithia-cyclocosa-phan-1(4),11(4)-diphenyl (L(3)); 1,12(2,6)-ditriazina-2,11,13,22-tetraaza-3,10,14,21-tetraoxo-6,7,17,18-tetrathia-cyclodocosaphan-1(4),12(4)-diphenyl (L(4)) were synthesised. The structural features of the compounds have been studied by elemental analyses, Mass, FT-Raman, FT-IR, (1)H and (13)C NMR spectroscopy. The antimicrobial activities of the ligands were evaluated using disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against several bacteria and yeast cultures. The obtained results from both methods were assessed in side-by-side comparison with commercial antibacterial and antifungal agents. In most cases, the compounds show strong antifungal activity in the comparison tests. Cytotoxic activities of the ligands against two different human cancer cell lines, stomach (23132/87) and lung (A549) were determined by MTT assay. DNA fragmentation assay tested cell lines were used to analyze the DNA ladder formation which is a characteristic of apoptotic cell death. The binding of the ligands with calf thymus DNA (CT-DNA) has also been investigated by absorption spectroscopy.

Synthesis, characterization and antimicrobial activity of water soluble dendritic macromolecules.

Several families of water soluble dendrimers were synthesized based on poly(propyleneoxide) amines (Jeffamines) (P(1)). P(1)-core and branched units were constructed from both methylacrylate and ethylenediamine (P(2)-P(9), and generations 0-3 with -NH(2), -COOH functionalities). They were characterized by elemental analysis (EA), gel permeation chromatography (GPC), FT-IR, (1)H, and (13)C NMR. The antimicrobial activities of only water soluble compounds (P(1), P(3), P(4), P(6), P(7) and P(9)) were evaluated using disk diffusion method in water as well as the minimal inhibitory concentration (MIC) dilution method against 9 bacteria. The obtained results from disk diffusion method are assessed in side-by-side comparison with those of Penicillin-g, Ampicillin, Cefotaxime, Vancomycin, Oflaxacin, and Tetracycline, well-known antibacterial agents. The results from dilution procedure are compared with Gentamycin as antibacterial and Nystatin as antifungal. The antifungal activities are reported on five yeast cultures namely, Candida albicans, Kluyveromyces fragilis, Rhodotorula rubra, Debaryomyces hansenii, and Hanseniaspora guilliermondii, and the results are referenced with Nystatin, Ketaconazole, and Clotrimazole, commercial antifungal agents. In most cases, the compounds show broad-spectrum (gram-positive and gram-negative bacteria) activities that are comparatively higher or equipotent to the antibiotic and antifungal agents in the comparison tests.

Raman, FT-IR, NMR spectroscopic data and antimicrobial activity of bis[micro2-(benzimidazol-2-yl)-2-ethanethiolato-N,S,S-chloro-palladium(II)] dimer, [(micro2-CH2CH2NHNCC6H4)PdCl]2.C2H5OH complex.

The 1,6-bis(benzimidazol-2-yl)-3,4-dithiahexane (1) ligand and its palladium(II) chloride complex [(micro(2)-SCH(2)CH(2)NHNCC(6)H(4))PdCl](2)xC(2)H(5)OH (2) have been synthesised and characterised by spectroscopical methods. The crystal structure of the triclinic title compound (P-1 (no. 2), a=879.6(1) pm, b=984.4(1) pm, c=1471.8(2) pm; alpha=94.330(6) degrees , beta=98.546(6) degrees , gamma=99.258(7) degrees , Z=2) was solved from X-ray single crystal diffraction data. In the binuclear complex, each palladium atom is coordinated in a slightly distorted square-planar arrangement by one nitrogen, two bridging sulphurs and one terminal chlorine atom. Molar conductivity, FT-Raman, FT-IR (mid-i.r., far-i.r.), (1)H and (13)C NMR spectra of the complex (2) have been recorded and show a good accordance with the square-planar geometry. The antimicrobial and antifungal activities of palladium(II) chloride, free ligand, its hydrochloride salt and the complex were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) the dilution method, against 10 bacteria and five yeast cultures. The results for the antibacterial from the disk diffusion method were assessed in side-by-side comparison with those for penicillin-g, ampicillin, cefotaxime, vancomycin, ofloxacin and tetracycline. Antifungal activities were referenced with nystatin, ketaconazole, and clotrimazole, commercial antifungal agents. The data from the dilution procedure were compared with gentamycin as antibacterial and nystatin as antifungal agent, respectively. In most cases, the compounds tested showed broad-spectrum (Gram positive and Gram negative) activities that were comparatively more active, or as potent as referenced pharmaceutical agents. The palladium complex has the potential to generate new kind of metabolites by displaying high affinities for most of the receptors compared with palladium chloride, free ligand and its hydrochloride salt.

Synthesis, characterization and antimicrobial activity of Fe(II), Zn(II), Cd(II) and Hg(II) complexes with 2,6-bis(benzimidazol-2-yl) pyridine ligand.

2,6-Bis(benzimidazol-2-yl)pyridine (L) ligand and complexes [M(L)Cl(2)] and [Fe(L)(2)](ClO(4))(2) (M=Zn, Cd, Hg) have been synthesized. The geometries of the [M(L)Cl(2)] complexes were derived from theoretical calculation in DGauss/DFT level (DZVP basis set) on CACHE. The central M(II) ion is penta-coordinated and surrounded by N(3)Cl(2) environment, adopting a distorted trigonal bipyramidal geometry. The ligand is tridentate, via three nitrogen atoms to metal centre and two chloride ions lie on each side of the distorted benzimidazole ring. In the [Fe(L)(2)](ClO(4))(2) complex, the central Fe(II) ion is surrounded by two (3N) units, adopting a octahedral geometry. The elemental analysis, molecular conductivity, FT-Raman, FT-IR (mid-, far-IR), (1)H, and (13)C NMR were reported. The antimicrobial activities of the free ligand, its hydrochloride salt, and the complexes were evaluated using the disk diffusion method in dimethyl sulfoxide (DMSO) as well as the minimal inhibitory concentration (MIC) dilution method, against 10 bacteria and the results compared with that for gentamycin. Antifungal activities were reported for Candida albicans, Kluyveromyces fragilis, Rhodotorula rubra, Debaryomyces hansenii, Hanseniaspora guilliermondii, and the results were referenced against nystatin, ketaconazole, and clotrimazole antifungal agents. In most cases, the compounds tested showed broad-spectrum (Gram positive and Gram negative bacteria) activities that were either more effective than or as potent as the references. The binding of two most biologically effective compounds of zinc and mercury to calf thymus DNA has also been investigated by absorption spectra.