Li-Xin You

Synthesis, characterization, and interaction with DNA of Cu(II) and Zn(II) complexes with 2,2′-bipyridyl-6,6′-dicarboxylic acid

Two transition metal complexes, [Cu2(bpdc)2H2O]·2H2O (1) and Zn(bpdc)(H2O)2 (2) (H2bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid), were synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction. Complex 1 is dinuclear with two five-coordinate cupric ions and 2 is mononuclear with one six-coordinate zinc. Interactions of 1 and 2 with DNA have been investigated using UV–Vis absorption spectra. The cleavage reaction on DNA has been monitored by agarose gel electrophoresis.

Bis(imidazole) coordination polymers controlled by oxalate as an auxiliary ligand

Seven coordination polymers {[M(L)2(H2O)2]·(NO3)2}n (M = Co (1), Ni (2), Cd (3)) and [M(L)(ox)]n (M = Co (4), Ni (5), Zn (6), and Mn (7)) have been synthesized (L = 2,6-bis(imidazol-1-yl)pyridine, ox = oxalate) under hydrothermal conditions. Single-crystal X-ray diffraction analysis has revealed that 1–3 are isomorphous and possess 2-D networks, whereas 4–6 are isomorphous, but involve two kinds of oxalate chains. The structure of 7 is different from those of 4–6 due to various bridging modes of the oxalate ligand. Magnetic studies have revealed that 1, 2, 4, 5, and 7 exhibit strong antiferromagnetic coupling. Among these, 1 exhibits an interesting spin-canting phenomenon. Graphical Abstract In hydrothermal reactions, seven coordination polymers were synthesized. Single-crystal X-ray diffraction analysis revealed that compounds 1–3 possess 2-D networks, whereas compounds 4–6 involve two kinds of oxalate chains. The structure of 7 adopts a 3-D framework structure due to various bridging modes of the oxalate ligand. Magnetic studies have revealed that compounds 1, 2, 4, 5, and 7 exhibit strong antiferromagnetic coupling.

A family of 3D lanthanide–organic frameworks constructed from parallelogram secondary building units: synthesis, structures and properties

A family of lanthanide–organic frameworks, {Ln2(pyip)(ox)2.5(H2O)5}n (Ln = La (1), Pr (2), Sm (3), Eu (4), Gd (5), Tb (6), Dy (7)) has been synthesized based on mixed bridging ligands, H2pyip and oxalate anion (H2pyip = 5-(4-pyridyl)-isophthalic acid, H2ox = oxalic acid) and characterized by elemental analysis, Fourier transform infrared spectroscopy, steady state and time-resolved luminescence spectroscopy, thermogravimetric analysis, powder X-ray diffraction and single-crystal X-ray diffraction. The single-crystal X-ray diffraction analysis results show that complexes 1–7 are isostructural. They crystallize in the same P21/c space group and exhibit a (3,4)-connected {42·6·82·10}{82·10} topology, being a 2-nodal net topology. The luminescence properties of 3, 4, 6, and 7 were investigated and related to the structural properties. The magnetic studies reveal that strong ferromagnetic coupling exists in compound 6.

Novel mononuclear Pt2 + and Pd2 + complexes containing (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid as a multi-donor ligand. Synthesis, structure, interaction with DNA, in vitro cytotoxicity, and apoptosis

New cytotoxic, mononuclear Pt and Pd coordination complexes featuring the planar, multi-donor ligand (2,3-f)pyrazino(1,10)phenanthroline-2,3-dicarboxylic acid (H2PPDA) have been synthesized under hydrothermal conditions (in water, at high temperature and pressure) and fully characterized. The complexes were proven to be isostructural by applying the single-crystal X-ray diffraction technique. UV-Vis and fluorescence spectroscopy investigations on their interaction with fish sperm DNA revealed a considerable binding capacity while gel electrophoresis provided evidence in favor of cleavage of pBR322 plasmid DNA. The newly synthesized complexes manifested significant in vitro cytotoxic activity against two different human cancer cell lines, the KB and JEKO cells, with cell death mainly caused by apoptosis.

2D and 3D lanthanide metal–organic frameworks constructed from three benzenedicarboxylate ligands: synthesis, structure and luminescent properties

Nineteen lanthanide–benzenedicarboxylate complexes were obtained under similar hydrothermal conditions: [Ln(IP-Py)(HIP-Py)(H2O)2]n (Ln = Pr (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6)), [Ln4(IP)6(H2O)4(DMF)·DMF·mH2O]n (Ln = Sm, m = 1 (7), Eu, m = 1.5 (8), Gd, m = 1.5 (9), Tb, m = 1.5 (10), Dy, m = 1 (11), Ho, m = 1.5 (12)), [Ln2(IP-Py)2(IP)(H2O)4·H2O]n (Ln = Sm (13), Eu (14), Tb (15), Dy (16)) and [Ln2(IP-Py)2(TP)(H2O)4·H2O]n (Ln = Sm (17), Eu (18), Gd (19)), where: H2IP-Py = 5-(4-pyridyl)-isophthalic acid), H2IP = isophthalic acid, H2TP = terephthalic acid. Complexes 1–6 exhibit a two-dimensional layered structure based on H2IP-Py. For 7–12, the Ln3+ ions are linked into one-dimensional chains with two triple-stranded helices of opposite handedness and further constructed into a two-dimensional layer by coordination of the IP2− ligands. For complexes 13–16 and 17–19, a similar two-dimensional layer was formed by coordination of Ln3+ and IP-Py2−, and three-dimensional pillar-layered frameworks were formed due to the layers bridged by the auxiliary IP2− or TP2− ligand, respectively. Most complexes show the characteristic narrow-banded lanthanide 4fN–4fN emission in combination with luminescence from the ligands, with the relative contribution depending on the energy transfer from the ligands to the lanthanides. The ligands play an important role in the sensitization of the lanthanide emission. The onset of the main excitation band for the Eu3+ complexes is found at the lowest energy for 14, enabling excitation by near-UV LEDs. The complexes containing the technologically relevant ions for (back) lighting applications, Tb3+ (green) and Eu3+ (red), are evaluated in detail in terms of luminescence lifetime and thermal stability. The emission intensity of selected Eu3+ and Tb3+ compounds is stable up to room temperature.

Synthesis, Crystal Structure, and Photoluminescent Properties of a Series of LnIII–CuI Heterometallic Coordination Polymers Based on Cu4I3 Clusters and Ln–ina Rod Units

A novel series of LnIII–CuI heterometallic coordination polymers (HCPs) {[Ln2Cu4I3(ina)7(DMA)2]n·nDMA, Ln = La (1), Ce (2), Pr (3) Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9) Ho (10), Er (11), Yb (12), Hina = isonicotinic acid, DMA = N,N-dimethylacetamide} were synthesised by a solvothermal reaction. The structures of compounds 1–12 were characterised by elemental analysis, FT-IR spectroscopy, thermogravimetric analysis, and powder X-ray diffraction. Single crystal X-ray diffraction studies revealed that 1–12 are isomorphous and are 3D heterometallic coordination polymers based on inorganic Cu4I3 clusters and Ln2(ina)7(DMA) rod units. In addition, the luminescent properties of compounds 5–9 have been investigated in detail. All of them exhibited green light emission due to the synergistic effects of characteristic emissions of lanthanide ions and iodide-to-copper charge transfer.