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A new Cu(II) complex with flavonoxylacetate ligand was synthesized and characterized. The structure of the complex was determined by X-ray single crystal diffraction technique. In the crystal structure, flavonoxylacetate coordinates Cu(II) ion in bidentate mode resulting in a chelating pentagonal coordination structure. Central Cu(II) has an elongated octahedral coordination showing a strong Jahn-Teller effect. The stability of the crystal structure was investigated by thermal gravimetric analyses. The loss of coordination water in crystals occurs above 150 °C. Fluorescence spectra are affected by pH value and coordination metal ion as well as the substitution pattern of the carboxymethoxy on the flavone skeleton. Furthermore, the fluorescence quenched in the Cu(II) complex recovered with increase of S2- ion concentration. [ABSTRACT FROM AUTHOR]

Two cobalt(II) complexes [Co(QCT)2]·Cl·1.5H2O (1) (QCT = quinoline-2-carboxaldehyde thiosemicarbazone) and [Co(QCMT)(CH3OH)Cl2] (2) (QCMT = quinoline-2-carboxaldehydeN4-methyl-thiosemicarbazone) have been synthesized and structurally characterized. Complex1crystallizes in a triclinic system with space groupP–1 and complex2crystallizes in a monoclinic system with space groupP2(1)/n. In both complexes the cobalt(II) center is six coordinated with distorted octahedral geometry. The interactions of two complexes with CT-DNA were investigated by electronic absorption spectra, circular dichroism (CD) spectra and fluorescence spectra. Results suggest that the complexes bind to DNAviagroove binding mode, and complex2has stronger binding ability than complex1. Thein vitrocytotoxicity has been tested against the human lung adenocarcinoma cell line A-549, cisplatin-resistant cell line A-549/CDDP, and human breast adenocarcinoma cell line MCF-7. Complex2is more cytotoxic than complex1, and both of them show higher cytotoxicity than the parent ligands alone. Compared with cisplatin, the two cobalt(II) complexes are more active against A-549/CDDP and MCF-7 cell lines at most experimental concentrations. Notably, although complex 2 is found to be less effective than cisplatin against the parent cell line A-549, it is much more effective than cisplatin against the resistant cell A-549/CDDP. [ABSTRACT FROM PUBLISHER]

A new macrocyclic dinuclear Zn(II) complex, [Zn2(OAc)L] · ClO4 (H2L was obtained by condensation between 3,3′-(ethane-1,2-diylbis(benzylazanediyl))bis(methylene)bis(2-hydroxy-5-methylbenzaldehyde) and aniline (1 : 2 molar ratio)), was synthesized and characterized by spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The interactions of the complex with DNA have been measured by UV spectroscopy and viscosity experiment. The interaction of the complex with calf thymus DNA has a binding constant of 1.18 × 104 mol−1 L. Phosphate hydrolysis of the complex was investigated using bis(4-nitrophenyl)phosphate as the substrate. The observed first-order rate constant is 4.23 × 10−5  s−1. [ABSTRACT FROM AUTHOR]

[Ni(QTS)2] · Cl · CH3OH, where QST = quinoline-2-carboxaldehyde thiosemicarbazone, has been synthesized and characterized. The complex crystallized in a monoclinic system with space group P2(1)/n. Nickel(II) is situated in a distorted octahedral geometry with two tridentate ligands and one ligand is mono-deprotonated to coordinate to nickel(II). Interaction of the nickel(II) complex with calf thymus DNA was investigated by electronic absorption, CD, and fluorescence spectra. The results suggest that nickel(II) complex binds to DNA through a groove binding mode. The nickel(II) complex exhibited efficient DNA cleavage at micromolar concentration in the presence of ascorbate with hydroxyl radicals as the active species. In vitro cytotoxicity assay showed that the nickel(II) complex was more potent against MCF-7 cell line but less active against A-549 cell line than cisplatin at the concentrations tested. [ABSTRACT FROM AUTHOR]

Two complexes, [Zn2L(µ-OAc)](ClO4) (1) and [Mn2L(OAc)2] · 4H2O (2), were synthesized by [2 + 2] cyclo-condensation between 2,6-diformyl-4-fluorophenol and 1,3-propyldiamine in the presence of metal ions M(II) (M = Zn and Mn), and were characterized by chemical analyses, IR spectra, electrospray mass spectra, and X-ray determinations. The results show that 1 forms dimers through hydrogen bonding. In 2, lattice waters, forming a 1-D water chain, function as glue to form a 3-D supramolecular network through extended hydrogen bonding. pBR322 plasmid DNA can be transformed to nicked form in air by 1 or nicked and linear forms in air by 2. Moreover, their antibacterial activities against S. aureus were investigated using penicillin as reference system. [ABSTRACT FROM AUTHOR]