Yun Qu

Assembly of Zn/Cd coordination polymers containing helixes or polycatenane structures tuned by the tri-pyridyl–bis-amide ligands with different spacer: syntheses, structures, photoluminescent and photocatalytic properties

Four new d10 metal–organic coordination polymers tuned by the “V”-shaped tri-pyridyl–bis-amide ligands with different spacers, namely, [Zn(L1)(BDC)]·H2O (1), [Cd(L1)(BDC)]·H2O (2), [Zn(L2)(BDC)] (3) and [Cd(L2)(BDC)] (4) (L1 = N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, L2 = N,N′-bis(pyridine-3-yl)pyridine-3,5-dicarboxamide, H2BDC = 1,4-benzenedicarboxylic acid) have been synthesized under hydrothermal conditions. In complexes 1 and 2, the metal ions are linked by L1 to form left- and right-helical Zn/Cd–L1 chains, which are further extended into two-dimensional (2D) wave-like layers by BDC anions. In 3, two L2 ligands link two ZnII ions forming the Zn2(L2)2 loops, which are connected by BDC anions to form a (2·65) topological 2D network. In addition, the large Zn2(L2)2 loops are threaded by the BDC rods from above and below 2D layers so as to form 2D → 3D polyrotaxane and polycatenane structures. In 4, the CdII ions are linked by L2 ligands to generate 1D double chain ribbons with Cd2(L2)2 loops, which are further connected by the BDC linkers to form a 3D framework. Two identical 3D frameworks interpenetrate each other in a twofold mode, giving rise to a polyrotaxane and polycatenane array, which is relative limited. The diverse structures of complexes 1–4 demonstrate that the tri-pyridyl–bis-amide ligands and the central metals have significant effect on the final structures. The thermal stability and fluorescent properties of complexes 1–4 have been investigated. In addition, the title complexes exhibit photocatalytic activity for dye methylene blue degradation under UV light.

pH-dependent two novel 3D polynuclear cobalt(II) cluster-based metal–organic frameworks constructed from a tri-pyridyl-bis-amide and a polycarboxylate: assembly, structures and properties

The hydrothermal reaction of CoCl2 with N,N′-bis(pyridine-3-yl)pyridine-3,5-dicarboxamide (L) and 1,3,5-benzenetricarboxylic acid (H3BTC) mixed ligands affords two novel polynuclear cobalt cluster-based metal–organic frameworks (MOFs), [Co3(L)2(BTC)2(H2O)2]·6H2O (1) and {[Co2(L)(BTC)(OH)]·2.5H2O}2 (2). Single crystal X-ray diffraction analysis reveals that the CoII ions in complex 1 are connected by BTC anions with a four-coordinated mode to form a two dimensional (2D) undulating layer based on dinuclear [Co2(COO)4] units, which is extended into a 3D (3, 4, 4, 5)-connected MOF by the L ligand with μ3-bridging coordination mode. In complex 2, the BTC ligand displays a six-coordinated mode to connect CoII ions into a 2D corrugated layer derived from tetranuclear [Co4(μ3-OH)2(COO)6] motifs, and the layers are further extended into a 3D (3, 8)-connected tfz-d MOF via μ2-bridging L ligands. The title complexes exhibit a (42·63·85)2(42·63·8)2(6·82)2(62·84) topology for 1 and a (43)2(46·618·84) topology for 2. The pH value, as well as the various coordination modes of the tri-pyridyl-bis-amide L and BTC ligands, play a crucial role in the construction of the diverse topological structures of 1 and 2. Complex 1 exhibits excellent photocatalytic activity for dye degradation under UV light. In addition, the electrochemical behaviour and magnetic and fluorescent properties of the two complexes have also been investigated.

Tuning the lead complexes based on a double 1,10-phenanthroline derivative with versatile coordination behavior by dicarboxylates: from 0D nano-ring to an unprecedented 0D + 3D cocrystal

Three lead metal–organic complexes, namely, [Pb(tpphz)(L1)(H2O)]·3H2O (1), [Pb(tpphz)1.5(L2)0.5(NO3)]·H2O (2) and [Pb3(tpphz)2(L3)3]·2H2O (3) {H2L1 = biphenylethene-4,4′-dicarboxylic acid, H2L2 = decanedioic acid, H2L3 = octanedioic acid, tpphz = tetrapyrido[3,2-a:2′,3′-c:3′′,2′′-h:2′′′,3′′′-j]phenazine} have been synthesized by employing a double phenanthroline derivative tpphz as the main ligand in the presence of different organic dicarboxylates under hydrothermal conditions. Single crystal X-ray diffraction analyses reveal that a bimetallic nano-ring complex (1) was obtained by using a long and rigid aromatic dicarboxylate (L1), and a 1D zigzag coordination polymer (2) was synthesized in the presence of a flexible fatty dicarboxylate (L2). When a shorter flexible fatty dicarboxylate (L3) was used then an unprecedented 0D + 3D cocrystal (3) was prepared. The tpphz ligands exhibited versatile coordination modes. The organic dicarboxylates with different flexibility and spacer length play an important role in adjusting the dimensions of the title lead complexes. Moreover, the thermal stability and fluorescent properties of complex 3 were also investigated.

Five bis(imidazole)-based Coordination Polymers Tuned by Central Metal Ions and S-containing Dicarboxylates: Syntheses, Structures, and Properties

Five new coordination polymers, namely [Zn(2-CMSN)(biim-4)] (1), [Co2(2-CMSN)2(biim-4)(H2O)4] (2), [Ni(2-CMSN)(biim-4)0.5(H2O)2] (3), [Cd(2-CMSN)(biim-4)0.5(H2O)2] (4), and [Cd(ADTZ)(biim-4)1.5]·5H2O (5), (2-H2CMSN = 2-carboxymethylsulfanyl nicotinic acid, H2ADTZ = 2,5-(S-acetic acid) dimercapto-1,3,4-thiadiazole, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole)) have been synthesised under hydrothermal conditions and structurally characterised by single-crystal X-ray diffraction analysis, infrared spectroscopy, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction. Complex 1 shows a 2D undulated sheet, which is constructed from 1D meso-helical [Zn-(biim-4)]n chains and linear [Zn-(2-CMSN)]n chains. Complexes 2–4 exhibit a similar 2D (4,4) grid network constructed from zigzag [M-(2-CMSN)]n chains and linear [M-(biim-4)]n chains (M = CoII, NiII and CdII), which possesses a ‘4+2’ type six-membered ring. Complex 5 displays a 3D architecture derived from 2D Cd-(biim-4) layers and double ADTZ linkers with diamond-type 66 topology. The effects of the central metals and S-containing dicarboxylates on the structures of the title coordination polymers have been discussed. The luminescent properties of complexes 1, 4, and 5 have been studied. Complex 5 exhibits photocatalytic activity for dye degradation under ultraviolet light and good stability towards photocatalysis.

Syntheses, Structures and Properties of Three Transition Metal Coordination Polymers Based on Semi-rigid 3-Pyridylnicotinamide and S/N-Containing Dicarboxylate Mixed Ligands

Three new coordination complexes, [Co(L)(ADTZ)]·H2O(1), [Cd(L)(ADTZ)]·H2O(2) and [Zn(L)(ADTZ)]·H2O(3)[L=3-pyridylnicotinamide, H2ADTZ=2,5-(s-acetic acid)dimercapto-1,3,4-thiadiazole], were synthesized under hydrothermal conditions. These complexes were structurally characterized by single-crystal X-ray diffraction analysis and further characterized by infrared spectroscopy(IR), powder X-ray diffraction(PXRD) and thermogravimetric analysis(TGA). Complexes 1–3 exhibit the similar 2D double-layer networks based on 1D [M-L]n zigzag chains and 1D [M-ADTZ]2n double-chains with different distances between metal ions and with various conformations of ADTZ anions. In complexes 1 and 3, the 2D sheets are extended into a 3D supramolecular frameworks by hydrogen bonding interactions. The subtle effects of the central metal atoms on the structures of the title coordination polymers were discussed. The electrochemical properties of complex 1 and luminescent properties of complexes 2 and 3 were investigated. In addition, complexes 1–3 exhibit photocatalytic activity for dye methylene blue degradation under UV light and show good stability toward photocatalysis.

Two new Pb(II) coordination polymers derived from fatty dicarboxylates and phenanthroline derivatives: syntheses, structures, and properties

Two new Pb(II) coordination polymers, [Pb(3-pdip)(L1)] · 0.5H2O (1) and [Pb(4-pdip)(L2)] (2) [L1 = heptane diacid, L2 = hexane diacid, 3-pdip = 2 -(3-pyridyl)imidazo[4,5-f]1,10-phenanthroline, 4-pdip = 2 -(4-pyridyl)imidazo[4,5-f]1,10-phenanthroline], have been obtained from hydrothermal reactions of Pb(II) nitrate with two flexible fatty carboxylic acids and two phenanthroline derivatives. Single-crystal X-ray diffraction analysis reveals that 1 is a 1-D staircase-like double chain coordination polymer extended by binuclear [Pb2N4O8] subunits and pairs of L1 ligands. Compound 2 exhibits a 2-D (4,4) network based on bi-metallic [Pb2N6O8] units and (L2)2/(4-pdip)2 double linkers. Furthermore, adjacent chains of 1 and layers of 2 are extended into 3-D supramolecular networks by π–π stacking interactions between aromatic rings of phenanthroline groups. The organic carboxylic acids with different lengths show great influence on the shapes of Pb(II)-carboxylate double chains. Phenanthroline derivatives possessing different sites of N-donors (3-pyridyl and 4-pyridyl) determine the final coordination frameworks of 1 and 2. Photoluminescence and thermal stabilities of 1 and 2 were also investigated.

Effects of metal ions and N-donor ligands with different coordination characters on the construction of d10 metal–organic complexes with selective photocatalytic activities

Four new d10 metal-organic coordination polymers, [Zn(L)(phen)(H2O)] (1), [Cd(L)(phen)] (2), [Zn(L)(bppdc)]·3H2O (3), and [Cd(L)(bppdc)]·3H2O (4) [L=2-carboxymethylsulfanyl nicotinic acid, phen=1,10-phenanthroline, bppdc=N;N`-bis(pyridin-3-yl)pyridine-2,6-dicarboxamide], have been obtained from hydrothermal reactions of zinc(II)=cadmium(II) nitrates with the semi-rigid N-= S-containing dicarboxylate L, and the two structurally disparate neutral N-donor ligands phen and bppdc. Single-crystal X-ray diffraction analysis has revealed that compound 1 is a one-dimensional (1- D) helical coordination polymer linked by ZnII atoms and L spacers. Compound 2 features a doublechain structure connected via binuclear CdII units and pairs of L linkers. Adjacent chains of 1 and 2 are packed into 3-D supramolecular networks by hydrogen bonds and p-p stacking interactions. Compounds 3 and 4 exhibit similar 2-D (4,4)-connected wave-like networks based on linear [M-L]n and zigzag [M-bppdc]n metal-organic chains (M=ZnII for 3 and CdII for 4). The effects of metal ions and N-donor ligands with different coordination characters are discussed. Moreover, the photoluminescence properties and photocatalytic activities of compounds 1 - 4 were investigated. Graphical Abstract Effects of Metal Ions and N-Donor Ligands with Different Coordination Characters on the Construction of d10 Metal-organic Complexes with Selective Photocatalytic Activities

Tuning 1-D Pb(II) Coordination Polymers by Flexible and Semirigid Dicarboxylates: Synthesis, Structure and Properties

Two new one-dimensional (1-D) Pb(II) coordination polymers, namely, [Pb(3-pdip)(L1)]·H2O (1) and [Pb(3-pdip)(L2)] (2) [L1H2 = 1,6-hexanedioic acid, L2H2 = homophthalic acid, 3-pdip = 2-(3-pyridyl)imidazo[4,5-f]1,10-phenanthroline] have been obtained from hydrothermal reactions of Pb(II) nitrate with the phenanthroline derivative and the two dicarboxylic acids. Single-crystal X-ray diffraction analysis reveals that compound 1 is a staircase-like double-chain coordination polymer constructed from binuclear [Pb2N4O8] subunits and pairs of [L1]2− anions. Compound 2 is a linear coordination polymer connected via two μ2-η2:η1 carboxylate groups from [L2]2− anions. Furthermore, adjacent chains of 1 and 2 are extended into 3-D supramolecular networks by hydrogen bonds and π-π stacking interactions. The organic carboxylic acids with different flexibility determine the structures of the coordination polymers. Moreover, the thermal stabilities and photoluminescence properties of compounds 1 and 2 were investigated. Graphical Abstract Tuning 1-D Pb(II) Coordination Polymers by Flexible and Semirigid Dicarboxylates: Synthesis, Structure and Properties