Search

A new Pb(II) complex, [Pb(8-OQ)(4-NB)], where 8-OQ = 8-hydroxyquinolinate, 4-NB = 4-nitrobenzoate, has been synthesized and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. The single crystal X-ray analysis reveals that the complex possesses a tetranuclear Pb4O4 cubane structure. The Pb(II) atom is coordinated by three triply bridging phenolic hydroxyl O atoms of 8-OQ ligands, then the tetranuclear Pb system is formed resulting in a tetrahedral cage. The interaction of complex with HS-DNA in Tris buffer was studied by UV−vis absorption spectrum and fluorescence ethidium bromide displacement experiment with an intrinsic binding constant of 1.52×104 M-1 and a linear Stern–Volmer quenching constant of 6.77×103 M-1. Anticancer activity against MCF-7, HepG-2 and A549 cell lines of complex was also determined by the MTT-based assay. The results showed the complex can inhibit proliferation of these three kinds of tumor cells and is less cytotoxic than cisplatin.

Glutathione (GSH) exhibits many cellular functions in human pathologies. A sensitive and simple method capable of assaying GSH would be useful to understand the mechanism of GSH-related diseases. In this study, a new colorimetric and fluorescent off-on probe, 3-oxo-3H-phenoxazin-7-ylthiophene-2-carboxylate, is constructed, synthesized and applied to determine fluctuations in intracellular GSH levels selectively and sensitively. The latent fluorescent probe is designed by reacting resorufin with thiophenecarboxylate and shows high sensitivity (LOD 8.9 × 10-7 M) and off-on fluorescent response to GSH over other different physiological species in pH 7.4 buffer solutions. A new reaction mechanism based on the cut-through of thiophenecarboxylate in the probe by GSH is confirmed via the HPLC (high performance liquid chromatography) and MS (mass spectrometry) analytical methods. Moreover, the probe is successfully applied to image GSH in A549 cells and indicates fluctuations in GSH levels under the stimulation of chemicals and drugs, which is verified by the investigation of the cell lysate with a commonly used commercial assay kit. As a result, it is feasible to monitor the levels of GSH in biosamples.

Three new complexes, {[Mn(2,2′-bipy)(4,4′-bipy)0.5(4-sb)(H2O)](H2O)2}n (1), [Mn(phen)2(4-sb)(H2O)](4,4′-bipy)0.5(H2O)3 (2), and [Fe2(phen)6](4-Hsb)(H2O)5 (3) [4-sb = 4-sulfobenzoate dianion, 2,2′-bipy = 2,2′-bipyridine, 4,4′-bipy = 4,4′-bipyridine, phen = 1,10-phenanthroline], have been synthesized and structurally characterized. The interaction of complex with HS-DNA was investigated by carrying out UV−vis absorption spectrum and fluorescence ethidium bromide displacement experiment. The DNA-binding constants Kb of complexes 1, 2, and 3 were calculated to be 7.39 × 105 M−1, 3.94 × 105 M−1, and 9.34 × 105 M−1, respectively. The results indicated that these complexes interact with HS-DNA through intercalative mode. Competitive studies with ethidium bromide (EB) further showed that the complexes bind to DNA probably via intercalation. The complexes were tested for antiproliferative activities on a panel of cell lines (MCF-7, HepG-2, A549, BGC823, and HTR-8) by MTT method, three complexes can inhibit the tumor cell proliferation, but complex 1 is less cytotoxic than other two complexes. The apoptosis assay was assessed with the Annexin-V/PI double staining methods and the results revealed that complexes induced the HepG-2 cells apoptosis.

A new one-dimensional (1D) coordination polymer, [Pb2(psa)(phen)2(NO3)2]n, has been synthesized by the method of hydrothermal reaction and characterized by elemental analysis, FT-IR and X-ray single-crystal diffraction (where H2psa is phenylsuccinic acid and phen is 1,10-phenanthroline). The single-crystal X-ray analysis showed that the complex has a dinuclear core stabilized by bridging phenylsuccinic acids and nitrate anions. The coordination number of the two Pb(II) atoms are 7 and 6, with the stereochemically active lone pair, resulting in the hemidirected geometry for the complex. The complex contain a 1D chain, which is further extended into two-dimensional supramolecular architecture through hydrogen bonds, C-H···π, and π···π interactions.