Antibacterial activities and DNA-cleavage properties of novel fluorescent imidazo-phenanthroline derivatives.

Design and biological activities of fluorescent imidazo-phenanthroline derivatives; (E)-5-((4-((4-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)phenoxy)methyl)benzylidene)amino)- isophthalicacid, 2 and 2-(4-(((5-chloroquinolin-8-yl)oxy)methyl)phenyl)-1H-imidazo[4,5f] [1,10]phenanthroline, 3, have been reported. Their characterizations were performed by spectroscopic techniques. Their promising photophysical behaviours were observed in absorbance and fluorescence studies. The antibacterial activities of the compounds were determined against seven different microorganisms; Bacillus subtilis ATCC 6633(G + ), Pseudomonas aeruginosa ATCC 29853(G-), Escherichia coli ATCC 35,218 (G-), Enterococcus faecalis ATCC 292,112 (G + ), Salmonella typhimurium ST-10 (G-), Streptococcus mutans NCTC 10,449 (G + ), and Staphylococcus aureus ATCC 25923(G + ). MIC values of 3 was determined as 156,25 µM on all tested bacteria. A preliminary study of the structure-activity relationship (SAR) also revealed that the antimicrobial activity depended on the substituents on the phenyl ring. The electron withdrawing Cl-substitued compound 3 most favour for antimicrobial activity even at lowest concentration compared to other compounds. DNA-cleavage activities of the compounds were also investigated. The interactions of the compounds with supercoiled pBR322 plasmid DNA were obtained by agarose gel electrophoresis. All imidazo-phenanthroline derivatives were found to be highly effective on DNA, even at the lowest concentrations because of their planar nature which provides ease of bind to the helix structure of DNA.

Carboxamide-Based Tripodal Fluororeceptors for Cations: Preparation, Characterization and Spectroscopic Studies.

Tripodal receptors, N-1,3,5-tris[2-(ethylamino)ethyl]benzene-1,3,5-tricarboxylamide (L1), N-1,3,5-tris[2-(phenylamino)ethyl]benzene-1,3,5tricarboxylamide (L2) and highly fluorescent N-1,3,5-tris[2(naphthalene-2-ylamino)-ethyl]benzene-1,3,5,tricarboxyl-amid)) (L3) were synthesized by the reaction of 1,3,5-benzene-tricarbonylchloride and different amine groups originally. Sensitivity measurements were performed with the addition of Fe(II), Cu(II), Hg(II), Zn(II), Ni(II), Mn(II), Cd(II), Ga(III), Co(II), Yb(III), Cr(III) and Ag(I) metals to the receptor solutions. According to the absorption and emission studies, these receptors show fluorescent property and Fe(II) ion quenches their fluorescence effectively.

Preparation of Different Substitued Polypyridine Ligands, Ruthenium(II)-Bridged Complexes and Spectoscopic Studies.

Novel different substitued polypyridine ligands 4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzaldehyde (BA-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzylidene)-pyrene-4-amine (PR-PPY), (E)-N-(4-((4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)methyl)benzylidene)-1,10-phenanthroline-5amine (FN-PPY), 2-(4-(bromomethyl)phenyl)-1H-imidazo[4,5-f][1,10] phenanthroline (BR-PPY), 2-(4-(azidomethyl)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (N3-PPY) and triazole containing polypyridine ligand 3,4-bis[(4-(metoxy)-1,2,3-triazole)1-methylphenyl)-1H-imidazo[4,5-f][1,10]phenanthroline)] benzaldehyde (BA-DIPPY) and Ruthenium(II) complexes were synthesized and characterized. Their photopysical properties were investigated. The complexes RuP(PR-PPY), RuB(PR-PPY, RuP(FN-PPY) and RuB(FN-PPY) exhibited a broad absorption bands at 485, 475, 476, and 453 nm, respectively, assignable to the spin-allowed MLCT (dπ-π*) transition. The emission maxima of the pyrene-appended polypyridine ligand PR-PPY was observed at λems = 616 nm and the phenanthroline-appended polypyridine ligand FN-PPY was observed at λems = 668 nm. And the emission maxima of the complexes RuP(PR-PPY), RuB(PR-PPY), RuP(FN-PPY) and RuB(FN-PPY) were observed at λems = 646, 646, 685 and 685 nm, respectively. As seen in fluorescence spectra, the fluorescence intensities of the ligands are higher than their metal complexes. This is because of quenching effect of Ruthenium(II) metal on chromophore groups.

Ruthenium (II) Complexes of Mono-, Di- and Tripodal Polypyridine Ligands: Synthesis, Characterization, and Spectroscopic Studies.

Mono-, di- and tripodal polypyridine ligands 4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenol (L1), 2-(4-(2-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzyloxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L2), 2-(4-(4-((4-(1H-imidazo[4,5-f][1,10]phenanthroline-2-yl)phenoxy)methyl)benzyl oxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L3), 2-(4-(4,6-bis(4-(1H-imidazo[4,5-f][1,10] phenanthroline-2-yl)phenoxy)-1,3,5-triazine-2-yloxy)phenyl)-1H-imidazo[4,5-f][1,10]phenanthroline (L4), and their Ru (II) complexes have been synthesized and characterized. All the ligands (L1-L4) gave the emissions at three shoulder at 278 nm, 315 nm, and 328 nm and the complexes (C1-C4) exhibit Ru (II) metal centered emission at 265 nm, 288 nm and 328 nm in acetonitrile solution at room temperature. Maximum d-π* transition seen at 462 nm for all the complexes.

Aromatic chromophore-tethered Schiff base ligands and their iron(III)/chromium(III) Salen and Saloph capped complexes.

Aromatic chromophores; pyrene, phenanthrene, anthracene, naphtalene and benzene-tethered Schiff base ligands and their iron(III)/chromium(III) Salen and Saloph capped complexes have been synthesized. Compounds have been characterized by means of FT-IR Spectroscopy, (1)H-NMR Spectroscopy, Magnetic Susceptibility, Elementel Analsis, TG/DTA measurements. Their fluorescence and absorbance properties have been investigated by Luminescence Spectroscopy and UV-vis Spectroscopy. Generally, ligands show an intense excimer fluorescence emissions in acetonitrile-methanol medium while iron(III) and chromium(III) complexes exhibit low fluorescence's. Intensity compared to ligands iron and chromium centers act as an extra chromophore that quench the pyrene, phenanthrene, anthracene, naphtalene and benzene molecules' singlet state. The mechanism of quenching is attributed to a iron (or chromium)-to-pyrene (or phenanthrene, anthracene, naphtalene and benzene) electronic energy transfer process.