Nai-Li Chen

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.

Polycarboxylate-directed various Co(II) complexes based on a “V”-like bis-pyridyl-bis-amide derivative: construction, electrochemical and photocatalytic properties

A series of new Co(II) complexes based on a new semi-rigid “V”-like bis-pyridyl-bis-amide derivative, namely, [Co(3-bpha)2(2,3-HPDC)2] (1), [Co(3-bpha)(3-NPH)(H2O)2]·2H2O (2), [Co(3-bpha)(1,3-BDC)]·4H2O (3), [Co(3-bpha)(HIP)]·3H2O (4), [Co(3-bpha)(MIP)(H2O)]·H2O (5), and [Co3(3-bpha)2(1,3,5-BTC)2(H2O)4]·2H2O (6) (3-bpha = N,N′-bis(pyridin-3-yl)-5-hydroxybenzene-1,3-dicarboxamide, 2,3-H2PDC = 2,3-pyridinedicarboxylic acid, 3-H2NPH = 3-nitrophthalic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, H2HIP = 5-hydroxyisophthalic acid, H2MIP = 5-methylisophthalic acid, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid), have been hydrothermally synthesized by tuning aromatic polycarboxylate co-ligands and characterized by single-crystal X-ray diffraction, IR spectra, powder XRD and TG analysis. Complex 1 is a discrete zero-dimensional (0D) structure in which the 3-bpha ligands and the 2,3-HPDC anions act as the terminal groups simultaneously to coordinate with the CoII ions. Complex 2 is a 1D meso-helical chain in which the 3-bpha ligands show a μ2-bridging mode and the 3-NPH anions act as the terminal groups. In complexes 3 and 4, pairs of 3-bpha ligands integrate with two CoII ions to generate 28-membered Co2(3-bpha)2 rings, which connect with the 1D [Co-1,3-BDC]n or [Co-HIP]n chains to create the 2D networks. In complex 5, the CoII ions are linked to 3-bpha ligands, resulting in a single-strand [Co-3-bpha]n helix chain, which is further connected to the MIP anions to form a 2D network. Complex 6 shows a 3D framework with (3,3,4)-connected (83)4(84·102) topology, which contains [Co-(1,3,5-BTC)]n 2D grid-like sheets and 1D [Co-3-bpha]n helical chains. Finally, the 0D discrete architecture in 1, 1D chain in 2, and 2D networks in 4 and 5 are extended to 3D supramolecular frameworks through hydrogen-bonding interactions. The effect of polycarboxylate auxiliary ligands with different substitute groups and different carboxyl positions and number on the assembly and structures of the target complexes were discussed. Moreover, the thermal stabilities, electrochemical properties and photocatalytic activities of complexes 1–6 were investigated.

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.

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.

Effect of solvent on the construction of Co(II) coordination polymers containing a semi-rigid bis(benzimidazole) derivative: syntheses, structures, and properties

Two Co(II) coordination polymers, [CoL(npa)]·2H2O (1) and [CoL(Hnpa)2] (2) (L = 1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene, H2npa = 5-nitroisophthalic acid), have been synthesized in different solvent systems and characterized by Infrared (IR) spectroscopy, elemental analysis, and powder and single crystal X-ray diffraction. Compound 1 was synthesized under solvothermal conditions with DMF as solvent and had a pair of L ligands adopting a μ2-bridging mode and connecting two Co2+ cations to generate a 26-membered Co2L2 loop. The npa2− link adjacent Co2L2 loops via a bis(monodentate) bridging mode to create a 1-D channel-like chain structure. Compound 2 was obtained under hydrothermal conditions, and the carboxylate of the monodeprotonated Hnpa− adopt a μ1-η0 : η1 coordination to connect adjacent Co2+ cations into a 2-D polymeric layer. The μ2-bridging L ligands connect adjacent 2-D [Co(Hnpa)]n polymeric layers into a 3-D NaCl-like framework. The Co2+ cations and the L ligands in compounds 1 and 2 exhibit different coordination geometries and conformations. Effects of solvents on the construction of Co(II) coordination polymers were investigated. In addition, the electrochemical behavior of carbon paste electrodes containing 1 and 2 and the thermal stabilities of 1 and 2 were investigated. Graphical Abstract

Structural Diversity and Properties of Six ZnII/CdII Coordination Polymers Based on an O-Bridged Semi-Rigid Bis-pyridyl-bis-amide and Different Dicarboxylates

Six new coordination polymers [Zn2(L)(chdc)2]·2H2O (1), [Zn(L)(mip)]·3H2O (2), [Zn(L)(bdc)]·H2O (3), [Cd2(L)(chdc)2]·2H2O (4), [Cd(L)(mip)]·2H2O (5), and [Cd(L)(bdc)]·2H2O (6) (L = N,N′-bis(pyridine-3-yl)-4,4′-oxybis(benzoic) dicarboxamide, 1,4-H2chdc = trans-1,4-cyclohexanedicarboxylic acid, H2mip = 5-methylisophthalic acid, 1,3-H2bdc = 1,3-benzenedicarboxylic acid) have been synthesized from ZnII/CdII ions and L ligands in the presence of auxiliary dicarboxylates via hydrothermal or solvothermal reaction. The coordination polymers have been fully characterized by infrared spectroscopy, powder X-ray diffraction, thermogravimetric analyses, and single-crystal X-ray diffraction analysis. Complex 1 contains a 1D [Zn4(chdc)4]n wave-like chain, which is connected by the μ2-bridging ligand L, affording a 3,4-connected 2D polymeric network. Complexes 2 and 3 both possess similar 2D 4-connected square grid-like layers, which are based on Zn-carboxylates linear chains and left-handed [Zn(L)]n helix chains. The structure of complex 4 is very similar to that of 1. Complexes 5 and 6 demonstrate a similar 2D 3,5-connected channel-level network, which is constructed from a pair of Cd-carboxylates linear chains and 1D [Cd2(L)2]n cyclic chains. The effects of the central metal ions and different dicarboxylates on the formation and structures of the title coordination polymers have been discussed. In addition, the fluorescence and photocatalytic properties of the title complexes have been 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