Ju-Wen Zhang

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.

The design and construction of a series of metal–organic coordination polymers based on two isomeric semi-rigid bis-pyridyl-bis-amide ligands and three aromatic polycarboxylates

A series of metal–organic coordination polymers, namely, {[Cu3(4-bpah)4(1,3,5-BTC)2]·8H2O}n (1), {[Cu3(4-bpah)3(1,2-BDC)3(H2O)2]·4H2O}n (2), {[Cu(4-bpah)(1,3-BDC)(H2O)]}n (3), {[Co(4-bpah)(1,3-BDC)(H2O)]}n (4), {[Ni(4-bpah)(1,3-BDC)(H2O)]}n (5), {[Zn(4-bpah)(1,3-BDC)(H2O)]}n (6), {[Cd(4-bpah)(1,3-BDC)]}n (7), {[Cd(3-bpah)(1,3-BDC)]·H2O}n (8), {[Cu2(3-bpah)(1,3-BDC)2]·H2O}n (9), where 4-bpah = N,N′-bis(4-pyridinecarboxamide)-1,2-cyclohexane, 3-bpah = N,N′-bis(3-pyridinecarboxamide)-1,2-cyclohexane, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, have been synthesized under hydrothermal conditions. The structures of 1–9 have been determined by single crystal X-ray diffraction analyses and further characterized by infrared spectroscopy (IR), elemental analyses, powder X-ray diffraction (PXRD), and thermogravimetric analyses (TGA). Complex 1 displays a 2D (42·83·10)(43·62·8)4(4)2 topological network. Complex 2 shows a 2D (3·4·5·62·7)2(3·42·52·7) topological framework that contains tri-flexural and left-hand helix chains. Complexes 3–6 reveal a similar 2D sql network with (44·62) topology. Complexes 7 and 8 show two different 2D double-layer structures with (42·6)(43·6·84·102)(4) and (42·6·86·12)(42·6)(8) topology, respectively. Complex 9 exhibits a new 3D 3-nodal topology with the Schlafli symbol (4·62)2(42·64)2(42·68·82·103). The successful construction of complexes 1–9 implies that using semi-rigid bis-pyridyl-bis-amide ligands can obtain various architectures with small voids. The effect of the isomeric semi-rigid bis-pyridyl-bis-amide ligands and the three aromatic polycarboxylates, as well as the central metal ions on the formation and structures of the title coordination polymers have been discussed. The fluorescent and photocatalytic properties of complexes 1–9 have also been investigated.

Construction and properties of cobalt(II)/copper(II) coordination polymers based on N-donor ligands and polycarboxylates mixed ligands

Metal–organic coordination polymers (MOCPs) are well known organic–inorganic hybrids with infinite structures consisting of metal ions/clusters and organic ligands linked through coordination interactions. MOCPs can be constructed from one or more than one organic bridging ligands (mixed-ligands) and different metal ions. The previous reports prove the fact that the nature of organic ligands and metal ions dominates the final structures as well as properties of the MOCPs in a certain way. Therefore, we focus on discussing the cobalt(II)/copper(II) coordination polymers constructed from the mixed-ligands of polycarboxylates and N-donor ligands, which may possess potential applications in the fields of electrochemistry, electrocatalysis, magnetism and photocatalysis. In this review, we summarize some typical Co(II)/Cu(II) MOCPs based on the mixed bridging organic ligands, aiming to discuss their versatile synthesis methods, topologies and structural influence factors, as well as their tunable properties. All of these aspects are highlighted in this review, which seeks to guide further investigations of cobalt(II)/copper(II) coordination polymers.

Transition metal carboxylate coordination polymers with amide-bridged polypyridine co-ligands: assemblies and properties

Coordination polymers (CPs) can be formed by the self-assembly of metal ions and one kind of ligand or mixed ligands. Carboxylate anions have been extensively utilized to construct metal–organic CPs with diverse structures and topologies as well as versatile properties. The introduction of neutral nitrogen-donor co-ligands in such metal carboxylate system is an effective strategy for tuning the architectures and functionalities of metal–organic CPs. As a family of neutral nitrogen-donor co-ligands, amide-bridged polypyridine compounds have been introduced into such metal carboxylate system in the past decade. A large number of metal–organic CPs derived from the mixed ligands of carboxylate and amide-bridged polypyridine have been reported. Therefore, we present the recent developments of transition metal carboxylate CPs with amide-bridged polypyridine co-ligands in this highlight. We summarize their syntheses, structures, architectural influence factors and properties in detail. Such highlight may play a significant role in the rational design and construction of amide-bridged polypyridine-based transition metal carboxylate CPs with structure-dependent properties.

Polyoxometalate-directed assembly of various multinuclear metal–organic complexes with 4-amino-1,2,4-triazole and selective photocatalysis for organic dye degradation

A series of polyoxometalate (POM)-based metal–organic complexes containing multinuclear Cu(II) clusters with a 4-amino-1,2,4-triazole (4-atrz) ligand, namely, [Cu3(4-atrz)8(PMo12O40)2(H2O)2]·2H2O (1), [Cu2(4-atrz)6(SiW12O40)(H2O)]·6H2O (2), [Cu2(4-atrz)4(μ2-OH)(CrMo6(OH)6O18)]·3H2O (3), [Cu3(4-atrz)3(Mo8O27)(H2O)4]·6H2O (4) and [Cu3(4-atrz)3(V10O30)0.5(μ3-OH)(H2O)]·H2O (5) have been synthesized by selectively adding additional citric acid or boric acid under hydrothermal conditions and have been structurally characterized by single-crystal X-ray diffraction and powder X-ray diffraction. Compound 1 has a zero-dimensional (0D) architecture, which is constructed from a linear trinuclear cluster [Cu3(4-atrz)8(H2O)2]6+ and two Keggin PMo12O403− anions. Compound 2 shows a 1D zigzag chain, in which the binuclear [Cu2(4-atrz)6(H2O)]4+ clusters and Keggin SiW12O404− anions connect to each other. Compound 3 is a 1D linear chain based on linear [Cu3(4-atrz)6]6+ clusters; the [CrMo6(OH)6O18]3− anions hang on two sides of the 1D chain. Compound 4 has a 2D layer constructed from trigonal [Cu3(4-atrz)3(H2O)4]6+ clusters and rare infinite [Mo8O27]n6n− chains. The [Mo8O27]6− anion is transformed from the Anderson-type [CoMo6(OH)6O18]3− anion, which is also rare in the POM-based reaction system. Compound 5 has a 3D framework constructed from trigonal trinuclear [Cu3(4-atrz)3(OH)]5+ clusters and rare [V10O30]10− polyanions, which represents the first example of a V10O30-based 3D metal–organic complex. Structural analyses indicate that different POMs show great effect on the various structures of 1–5 and the additional acids play an important role in the formation of 1–5. Photocatalytic experiments of 1–5 on degradation of three organic dyes (methylene blue, Rhodamine B and methyl orange) manifest that compounds 1–3 are good candidates for the photocatalytic degradation of methylene blue, and compound 1 is a good photocatalyst for the degradation of Rhodamine B.

Role of aromatic dicarboxylates in the structural diversity of cobalt(II) and copper(II) coordination polymers containing a flexible N,N′-di(3-pyridyl)octanediamide ligand

Six new transition metal coordination polymers, namely, [Co(1,2-BDC)(L)1.5(H2O)] (1), [Co(1,3-BDC)(L)(H2O)2]·H2O (2) [Co(5-AIP)(L)0.5(H2O)]·2H2O (3), [Cu(1,2-BDC)(L)] (4), [Cu(1,3-BDC)(L)(H2O)]·3H2O (5), and [Cu2(5-AIP)2(L)2(H2O)]·6H2O (6) (L = N,N′-di(3-pyridyl)octanediamide, 1,2-H2BDC = 1,2-benzenedicarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, 5-H2AIP = 5-aminoisophthalic acid), have been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. In compound 1, the adjacent CoII ions are connected by L ligands to form a 1D chain with an alternating arrangement of L ligands and Co2L2 dinuclear loops. The 1,2-BDC anions coordinate with one CoII ion in a bis(monodentate) chelate mode. Complex 2 shows a 2D (44) grid network with the sql topology, which consists of the 1D zigzag [Co–L]n chain and 1D linear [Co-1,3-BDC]n chain. When 5-H2AIP is used in compound 3, an interesting 2D terraced-type layer based on 1D [Co-5-AIP]2n ladder-like chains and μ2-bridging L ligands with 3,4-connected {62.10}{6} topology is formed. Under the similar conditions to compound 1, except that the cobalt(II) salt is replaced by a copper(II) salt, a 2D wave-like network 4 with 2,4-connected {64.8.10}{6} topology is obtained. Compound 5 displays a 3D coordination polymeric architecture based on 1D [Cu-1,3-BDC]n chains and [Cu–L]n chains, which represents an intriguing 3-fold interpenetrating framework with CdSO4-type topology. When 1,3-BDC is replaced by 5-AIP, another 3-fold interpenetrating 3D CdSO4-type coordination framework for compound 6 is obtained, which is constructed from three types of 1D chains: [La–Cu–Lc]n chain, [Lb–Cu–Lb]n chain and [Cu-5-AIP]n chain. The adjacent 1D chains for 1 and 2D layers for compounds 2, 3 and 4 are further extended by hydrogen bonding interactions to 3D supramolecular frameworks. The effect of dicarboxylates and central metals on the structures of the title complexes has been discussed. Furthermore, the electrochemical behaviors and solid state fluorescent properties for compounds 1–6 are investigated.

Two novel Anderson-type polyoxometalate-based metal–organic complexes with high-efficiency photocatalysis towards degradation of organic dyes under UV and visible light irradiation

Two novel Anderson-type polyoxometalate (POM)-based metal–organic complexes (MOCs), namely, H{CuL0.51 [CrMo6(OH)6O18](H2O)}·0.5L1 (1) and {Cu2(L2)2[CrMo6(OH)5O19](H2O)2}·2H2O (2) (L1 = N,N′-bis(3-pyridinecarboxamide)-1,2-ethane, L2 = N,N′-bis(3-pyridinecarboxamide)-1.3-propane), were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). In complex 1, the bidentate [CrMo6(OH)6O18]3− (CrMo6) polyoxoanions bridge the CuII ions to generate a 1D Cu–CrMo6 inorganic chain, which is further connected by the μ2-bridging L1 ligands to form a 1D ladder-like chain. Complex 2 is a 3D POM-based metal–organic framework exhibiting a {412.63} topology, which is constructed from the quadridentate CrMo6 polyoxoanions and μ2-bridging L2 ligands. The flexible bis-pyridyl-bis-amide ligands with different spacer lengths have a significant effect on the final structures. In addition, pH shows great influence on the formation of the single-crystal phase. The photocatalytic activities of the title complexes on the degradation of methylene blue (MB) and rhodamine B (RhB) under UV and visible light have been investigated in detail.

Polyoxometalate-directed assembly and various structures of inorganic–organic hybrid compounds based on a semi-rigid bis-pyridyl-bis-amide

Through tuning different kinds of polyoxometalates (POMs), four POM-based inorganic–organic hybrid compounds with different dimensionalities, namely [(H2L)2(Mo8O26)] (1), [CuII2L6(P2W24O79)·4H2O]·7H2O (2), {CuII2L2(μ2-OH)[CrMo6(OH)6O18]·4H2O}·4H2O (3), and {CuI2CuII2L2(μ3-OH)2[CrMo6(OH)5O19]·6H2O}·4H2O (4) [L = 1,4-bis(3-pyridinecarboxamido)benzene], have been synthesized under hydrothermal conditions and characterized by IR spectroscopy, TG analysis, powder XRD and single-crystal X-ray diffraction. Single-crystal X-ray analyses reveal that compound 1 exhibits a two-dimensional (2D) supramolecular network, which is constructed from protonated L ligands and [Mo8O26]4− anions through hydrogen bonding interactions. Compound 2 is a 1D hybrid chain based on an uncommon inorganic [P2W24O79]4− chain and “Y”-shaped (CuL3)2+ subunits. Compound 3 shows a 2D network constructed from 1D inorganic Cu2–CrMo6 chains and bidentate L ligands, which is obtained at pH = 4.1. When the pH was adjusted to 4.8, compound 4 is obtained which exhibits a 4-connected {66} 3D framework. The CrMo6 anions are connected by adjacent [CuI2CuII2(μ3-OH)2(H2O)6]4+ subunits to form 1D Cu4–CrMo6 inorganic chains, which are further extended by L ligands to construct a 3D network. The effect of different types of polyanions and pH values on the assembly and various structures of the title compounds has been discussed. Furthermore, the electrochemical properties of 1 and 2, and the photocatalytic properties of 2 and 3 under different conditions have been investigated.

Systematic Investigation of Reaction-Time Dependence of Three Series of Copper–Lanthanide/Lanthanide Coordination Polymers: Syntheses, Structures, Photoluminescence, and Magnetism

Three series of copper-lanthanide/lanthanide coordination polymers (CPs) Ln(III) Cu(II) Cu(I) (bct)3 (H2 O)2 [Ln=La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Er (10), Yb (11), and Lu (12), H2 bct=2,5-bis(carboxymethylmercapto)-1,3,4-thiadiazole acid], Ln(III) Cu(I) (bct)2 [Ln=Ce (2 a), Pr (3 a), Nd (4 a), Sm (5 a), Eu (6 a), Gd (7 a), Tb (8 a), Dy (9 a), Er (10 a), Yb (11 a), and Lu (12 a)], and Ln(III) 2 (bct)3 (H2 O)5 [Ln=La (1 b), Ce (2 b), Pr (3 b), Nd (4 b), Sm (5 b), Eu (6 b), Gd (7 b), Tb (8 b), and Dy (9 b)] have been successfully constructed under hydrothermal conditions by modulating the reaction time. Structural characterization has revealed that CPs 1-12 possess a unique one-dimensional (1D) strip-shaped structure containing two types of double-helical chains and a double-helical channel. CPs 2 a-12 a show a three-dimensional (3D) framework formed by Cu(I) linking two types of homochiral layers with double-helical channels. CPs 1 b-9 b exhibit a 3D framework with single-helical channels. CPs 6 b and 8 b display visible red and green luminescence of the Eu(III) and Tb(III) ions, respectively, sensitized by the bct ligand, and microsecond-level lifetimes. CP 8 b shows a rare magnetic transition between short-range ferromagnetic ordering at 110 K and long-range ferromagnetic ordering below 10 K. CPs 9 a and 9 b display field-induced single-chain magnet (SCM) and/or single-molecule magnet (SMM) behaviors, with Ueff values of 51.7 and 36.5 K, respectively.

Effect of polyoxoanions and amide group coordination modes on the assembly of polyoxometalate-based metal–organic complexes constructed from a semi-rigid bis-pyridyl-bis-amide ligand

A series of polyoxometalate (POM)-based metal–organic complexes constructed from a semi-rigid bis-pyridyl-bis-amide ligand have been hydrothermally synthesized and structurally characterized: [Cu2L2(PMoVI11MoVO40)(H2O)2]·2H2O (1), [Cu2L2(PWVI11WVO40)(H2O)6]·H2O (2), [Cu2L2(SiW12O40)(H2O)6]·H2O (3) and [Cu2L2(H2K2Mo8O28)(H2O)2] (4) (L = N,N′-bis(3-pyridinecarboxamide)-piperazine). Single-crystal X-ray analyses reveal that complex 1 is a 2D metal–organic architecture based on the Keggin-type [PMoVI11MoVO40]4− anions and quadrate Cu2L2 loops. Isostructural complexes 2 and 3 display 2D supramolecular networks based on 1D infinite chains, which are constructed from quadrate Cu2L2 loops and Keggin polyoxoanions. Complex 4 exhibits a 3D metal–organic framework derived from the newly-reported [K2Mo8O28]6− polyoxoanions and quadrate Cu2L2 loops. The L ligands show a μ3-bridging coordination mode (via ligation of two pyridyl nitrogen atoms and one carbonyl oxygen atom) in 1 and 4, and a μ2-bridging coordination mode (via ligation of two pyridyl nitrogen atoms) in 2 and 3, forming Cu2L2 loops in 1–4. The influence of amide group coordination modes and structural features of POMs on the structures of the title complexes has been discussed. The electrochemical properties and selective photocatalytic properties of the title complexes have been reported in this article.