Synthesis, crystal structure, interaction with BSA and antibacterial activity of La(III) and Sm(III) complexes with enrofloxacin.

Two new La(III) and Sm(III) complexes with enrofloxacin (HER, 1-cyclopropyl-7-(4-ethyl-1-piperazinyl)-6-fluoro-1,4-dihydro-4-oxo-3-quinoline carboxylic acid, C(19)H(21)FN(3)O(3)), [La(2)(ER)(6)(H(2)O)(2)]·14H(2)O(1) and [Sm(2)(ER)(6)(H(2)O)(2)]·14H(2)O(2) have been synthesized and characterized by elemental analysis, FT-IR, TG-DTG and X-ray single crystal diffraction. Both of the complexes are triclinic system with space group Pi. The structure of the complexes show that each rare earth atom in both complexes was nine-coordinated. Two of the enrofloxacin ions acted as tridentate chelate and bridging ligands, while the others as bidentate chelate ligands. The binding reaction between the complexes and bovine serum albumin (BSA) was studied by UV-vis absorption spectra and fluorescence spectroscopy. The results indicated that the two complexes had a quite strong ability to quench the fluorescence from BSA and the binding reaction was mainly a static quenching process. The binding constants K ( A )/(L·mol(-1)) were 1.46 × 10(5)(1) and 8.59 × 10(6)(2) and one binding site was formed. The synchronous spectroscopy suggested that tryptophan residues were placed in BSA. It was also found that the two complexes exhibited greater antimicrobial activity than enrofloxacin at given concentrations.

Synthesis, characterization, DNA-binding and antiproliferative activity of Nd(III) complexes with N-(nitrogen heterocyclic) norcantharidin acylamide acid.

Three novel complexes [Nd(L)(NO3)(H2O)2].NO(3).2H2O (HL1 = N-pyrimidine norcantharidin acylamide acid, C12H13N3O4; HL2 = N-pyridine norcantharidin acylamide acid, C13H14N2O4; HL3 = N-phenyl norcantharidin acylamide acid, C14H15NO4) were synthesized. HL1, HL2 and HL3 are the ligand of complex(1), complex(2) and complex(3), respectively. Their structures were characterized by elemental analysis, conductivity measurement, infrared spectra and thermogravimetric analysis. The DNA-binding properties of the complexes have been investigated by fluorescence spectroscopy and viscosity measurements. The results suggest that the complexes can bind to DNA by partial intercalation. The liner Stern-Volmer quenching constant Ksq values are 3.3(+/-0.21)(1), 1.7(+/-0.19)(2) and 0.9(+/-0.04)(3), respectively. Complex (1) and (2) have been found to cleave pBR322 plasmid DNA at physiological pH and temperature. The test of antiproliferation activity indicates that complex(1) has strong antiproliferative ability against the SMMC7721 (IC50 = 131.7 +/- 23.4 micromol x L(-1)) and A549 (IC50 = 128.4 +/- 19.9 micromol x L(-1)) cell lines. The inhibition rates of complex(2) (IC50 = 86.3 +/- 11.3 micromol x L(-1)) are much higher than that of NCTD (IC50 = 115.5 +/- 9.5 micromol x L(-1)) and HL2 (111.0 +/- 5.7 micromol x L(-1)) against SMMC7721 cell lines.

catena-Poly[[diaqua-copper(II)]-µ-7-oxa-bicyclo-[2.2.1]heptane-2,3-dicarboxyl-ato].

In the crystal structure of the title compound, [Cu(C(8)H(8)O(5))(H(2)O)(2)](n), the Cu(II) cation is in a Jahn-Teller distorted six-coordination by two O atoms from water molecules, by the bridging O atom from the bicyclo moiety, by two carboxylate O atoms from two different carboxylate groups and by one carboxylate O atom from a symmetry-related bridging ligand.The polymeric structure is made up from double-strands propagating parallel to the c axis that are held together via inter-molecular O-H⋯O hydrogen bonds.

Diaqua-bis(ciprofloxacinato)manganese(II) 2,2'-bipyridine solvate tetrahydrate.

In the crystal structure of the title compound {systematic name: diaquabis-[1-cyclo-propyl-6-fluoro-4-oxo-7-(piperazin-1-yl)-1,4-dihydro-quinoline-3-carboxyl-ato]manganese(II) 2,2'-bi-pyridine solvate tetrahydrate}, [Mn(C(17)H(17)FN(3)O(3))(2)(H(2)O)(2)]·C(10)H(8)N(2)·4H(2)O, the pyridone O and one carboxyl-ate O atom of the two ciprofloxacin ligands are bound to the Mn(II) ion and occupy the equatorial positions, while the two aqua O atoms lie in the apical positions resulting in a distorted octa-hedral geometry. The crystal packing is stabilized by N-H⋯O and O-H⋯O hydrogen bonding interactions.

catena-Poly[[diaqua-nickel(II)]-µ-7-oxabicyclo-[2.2.1]heptane-2,3-di-carboxyl-ato].

In the crystal structure of the title compound, [Ni(C(8)H(8)O(5))(H(2)O)(2)](n), the Ni(II) cation is in a Jahn-Teller-distorted octahedral coordination environment binding to two O atoms from water molecules, the bridging O atom of the bicycloheptane unit, two carboxylate O atoms from different carboxylate groups and one carboxylate O atom from a symmetry-related bridging ligand. The crystal structure is made up from layers propagating parallel to the bc plane.

Tris(1H-imidazole-κN)(7-oxabicyclo-[2.2.1]heptane-2,3-dicarboxyl-ato-κO,O,O)cobalt(II) 3.35-hydrate.

In the crystal structure of the title compound, [Co(C(8)H(8)O(5))(C(3)H(4)N(2))(3)]·3.35H(2)O, the central Co(II) ion is in a slightly distorted octa-hedral environment, coordinated by the bridg-ing O atom from the bicyclo-[2.2.1]heptane ligand, by two carboxyl-ate O atoms from two different carboxyl-ate groups and by three N atoms from imidazole ligands. Uncoordinated water mol-ecules, some of them disordered, are present in the crystal structure. In the crystal structure, mol-ecules are linked by O-H⋯O, N-H⋯O and O-H⋯N hydrogen-bonding inter-actions.

The 1:1 cocrystal of rac-7-oxabicyclo-[2.2.1]heptane-2,3-dicarboxylic acid and 2-amino-benzothia-zole.

In the crystal structure of the title compound, rac-7-oxabicyclo-[2.2.1]heptane-2,3-dicarboxylic acid-2-amino-benzo-thia-zole (1/1), C(8)H(10)O(5)·C(7)H(6)N(2)S, mol-ecules of each component are linked into centrosymmetric dimers by inter-molecular N-H⋯O hydrogen bonds. These dimers are connected by O-H⋯O hydrogen bonds into a chain along the b axis. In addition, π-π inter-actions between aromatic heterocycles occur [centroid-centroid distance of 3.4709 Šand inter-planar spacing of 3.4374 Šbetween symmetry-related benzothia-zole ring systems.

[Synthesis and study on the interaction of rare earth complexes of N', N-bis(2-pyridinecarboxamide)-1, 2-ethane with DNA].

Four rare earth complexes of N', N-bis(2-pyridinecarboxamide)-1, 2-ethane were synthesized and characterized by elemental analysis, conductivity measurement, thermal studies, IR and electronic spectra. The composition of the four complexes is [Ln(H2L)(NO3)2](NO3) x 3H2O (Ln=Sm, Eu, Gd, Tb). Results of spectral measurements indicate that the oxygen of carbonyl and the nitrogen of pyridyl coordinate with Ln(III) respectively, and the NO3- shows bidentate coordination. So the four complexes are 1 : 1 chelated complexes. The interaction between [Sm(H2L) (NO3)2](NO3) x 3H2O and DNA was studied by employing UV-Visible (UV-Vis) spectra, fluorescence spectra and SERS spectra. Experimental results show that with the incremental addition of DNA, the bands at 265 nm show hypochromism accompanied by a small red shift and the binding constant Kb Obtained is 1.24 x 10(5). Meanwhile fluorescence spectra show that the addition of [Sm(H2L) (NO3)2] (NO3) x 3H2O to DNA pretreated with EB causes an appreciable reduction in fluorescence intensity, indicating that the complex competes with ethidium bromide in binding to DNA, and free ethidium bromide increases. The addition of DNA causes the SERS signals of the complex to weaken and the band at 1 282 cm(-1) to disappear, which suggests that the planar pyridine molecule of the ligand may partly be inserted into the double-stranded helix plane in DNA, making pi electronic density of aromatic rings in complex change. The above phenomena indicate that [Sm(H2L) (NO3)] (NO3) x 3H2O interacts intensively with DNA.

Synthesis, characterization and DNA-binding studies on La(III) and Ce(III) complexes containing ligand of N-phenyl-2-pyridinecarboxamide.

La(III) and Ce(III) complexes containing ligand of N-phenyl-2-pyridinecarboxamide (HL) were synthesized and characterized by elemental analyses, conductivity measurement, IR spectra and thermal analysis. The general formulas of the complexes were [Ln(HL)(3)(H(2)O)(2)](NO(3))(3).2H(2)O [Ln=La(III), Ce(III)]. The results indicated that the oxygen of carbonyl and the nitrogen of pyridyl coordinated to Ln(III), and there were also two water molecules taking part in coordination. Ln(III) and HL formed 1:3 chelate complexes and the coordination number was eight. The interaction between the complexes and DNA was studied by means of UV-vis spectra, fluorescence spectra, SERS spectra and agarose gel electrophoresis. The results showed that complexes can bind to DNA. The binding ability decreased in following order: La(III) complex, Ce(III) complex, and HL. The interaction modes between DNA and the three compounds were found to be mainly intercalative.

[Studies on the interaction of metalic complex and DNA by the spectral methods].

The interaction of [Cu(A)2]2+ (A = phen, bpy, en) complex ion and ct-DNA was investigated by using absorption spectra and fluorescence spectra. Based on the measurement of A260 in the different pH mediums, the alkaline denaturation curves of DNA in the absence and in the presence of [Cu(phen)2]2+ complex ion were obtained. The result showed that the alkaline denaturation for [Cu(phen)2]2+ complex ion occured at a higher pH than that for DNA alone. The absorption of EB-DNA system in the presence of [Cu(phen)2]2+ showed that [Cu(phen)2]2+ could partly sustain the place of EB. The result of fluorescence spectra suggested that the [Cu(phen)2]2+ complex ion could make the fluorescence intensity of EB-DNA system to decreased sharply. The effect of [Fe(CN)6]4- on the emission of [Cu(phen)2]2+ and [Cu(phen)2](2+) -DNA system was studied. All the experimental results indicated that the intercalative binding mode was the major mode for the interaction of [Cu(phen)2]2+ complex ion and DNA, and the size of ligands can effect the binding of complexes to DNA.