Shu-Ju Wang

Hydrothermal synthesis, crystal structure and properties of Ni(II)–4f complexes based on 1H-benzimidazole-5,6-dicarboxylic acid

Nine novel heterometallic coordination polymers [Ln(2)Ni(Hbidc)(2)(SO(4))(2)(H(2)O)(8)](n) (Ln = Pr (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), Ho (7), Er (8), Yb (9), H(3)bidc = 1H-benzimidazole-5,6-dicarboxylic acid) have been synthesized under hydrothermal conditions and characterized by elemental analysis, FT-IR, TG analysis and single crystal X-ray diffraction. X-ray analysis revealed that all complexes present almost identical three-dimensional (3D) structures with PtS-type topology. Complexes 1-7 are all isomorphous, and the structure variation of polymers 8 and 9 is induced by the lanthanide contraction effect. In additional, the luminescence properties of complexes 2, 3 and 5-7, and the magnetic properties of complexes 4 and 6-8 were investigated.

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.

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.