Jian Luan

Unprecedented Application of Flexible Bis(pyridyl-tetrazole) Ligands To Construct Helix/Loop Subunits To Modify Polyoxometalate Anions

By introducing the unprecedented and flexible isomeric bis(pyridyl-tetrazole) ligands into a polyoxometalates (POMs) system, three POM-based compounds, {Ag2(4-bptzb)2(H2O)2[H2PMo12O40]2}·4-bptzb·5H2O (1), [Ag4(3-bptzb)2(PMo(V)Mo(VI)11O40)]·2H2O (2), and Ag3(3-bptzb)2.5(H2O)2[H3P2W18O62] (3) [4-bptzb = 1,4-bis(5-(4-pyridyl)tetrazolyl)butane and 3-bptzb =1,4-bis(5-(3-pyridyl)tetrazolyl)butane], were synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analyses. Compound 1 exhibits a dimeric structure constructed from two Keggin [PMo12O40](3-) anions and a binuclear [Ag2(trans-4-bptzb)2](2+) subunit in which the trans-4-bptzb acts as a bidentate bridging ligand with one tetrazolyl group. In 2, the 3-bptzb acts as a tetradentate bridging ligand with the tetrazolyl and pyridyl groups linking Ag(I) ions to generate a 3D metal-organic framework (MOF), which contains charming meso-helix chains. The Keggin anions acting as bidentate inorganic ligands reside in the distorted tetragonal channels of the MOF. In compound 3, the 3-bptzb adopts versatile coordination modes linking Ag(I) ions to first construct loop connecting loop 1D chains, which are linked by {Ag[P2W18O62]}n zigzag chains to form a scarce hamburger-style 2D sheet. These adjacent sheets are further fused by 3-bptzb ligands to construct a 3D framework. The influences of isomeric bptzb ligands and POMs on the construction of Ag-bptzb subunits and the whole structures of the title compounds are discussed. The electrochemical behaviors and electrocatalytic activities of compounds 2 and 3 and their corresponding parent POMs as well as the fluorescent properties of the title compounds have been studied in detail. In addition, the photocatalytic activities of compounds 2 and 3 and their corresponding parent POMs for decomposition of methylene blue, rhodamine B, and methyl orange under UV irradiation have also been investigated.

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.

Two novel octamolybdate-based frameworks decorated by flexible bis-pyridyl-bis-amide ligands with different spacer lengths

Two octamolybdate hybrid complexes based on flexible bis-pyridyl-bis-amide ligands with different spacer lengths, namely, {[Cu(L1)(β-Mo8O26)0.5(H2O)2]·H2O}n (1), [Cu(L2)(β-Mo8O26)0.5(H2O)] (2) (L1 = N,N′-bis(3-pyridinecarboxamide)-1,2-ethane, L2 = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane), have been successfully synthesized. Crystal structure analysis reveals that 1 is a two-dimensional (2D) network constructed from [Cu-L1]n2n+ chains and [β-Mo8O26]n4n− anions, displaying a 4-connected framework with 32·62·72 topology. Compound 2 consists of double one-dimensional (1D) meso-helical chains and 1D inorganic chains to generate a three-dimensional (3D) framework with a (4,4)-connected (4·64·8)2(42·62·82) topology. The title compounds represent the first examples of introducing a flexible bis-pyridyl-bis-amide ligand into the isopolymolybdates system. In addition, the electrochemical behavior of 1, luminescent properties and photocatalytic activities of the title compounds have been investigated.

Assembly and properties of four new metal-organic coordination polymers with flexible bis-pyridyl-bis-amide ligands: Effect of aromatic dicarboxylates and central metal ions on the structures

Four coordination polymers, [Cu(4-dpyh)0.5(1,2-BDC)(H2O)3]·H2O (1), [Cu(4-dpyh)(1,3-BDC)(H2O)] (2), [Cd(3-dpyh)0.5(1,3-BDC)(H2O)2]·H2O (3), and [Zn(3-dpyh)(1,3-BDC)]·3H2O (4) [4-dpyh = N,N′-bis(4-pyridinecarboxamide)-1,6-hexane, 3-dpyh = N,N′-bis(3-pyridinecarboxamide)-1,6-hexane, 1,2-H2BDC = 1,2-benzenedicarboxylic acid and 1,3-H2BDC = 1,3-benzenedicarboxylic acid], have been hydrothermally synthesized. X-ray diffraction analyses reveal that 1 is a discrete [Cu2(4-dpyh)(1,2-BDC)2] dinuclear structure. Compound 2 exhibits a 2-D grid layer constructed from 1-D linear [Cu(1,3-BDC)]n chains and [Cu(4-dpyh)]n chains. Compound 3 features a 1-D ladder-like chain formed by the 1-D linear [Cd(1,3-BDC)]n chains and 3-dpyh bridging ligands. Compound 4 displays a 2-D undulated layer containing meso-helical [Zn(3-dpyh)]n chains and linear [Zn(1,3-BDC)]n chains. The neighboring dinuclear complexes for 1, adjacent chains for 3, and adjacent layers for 2 and 4 are further linked by hydrogen bonding interactions to form 2-D (for 1) or 3-D supramolecular networks (for 2–4). The influences of the different dicarboxylates and metal on the structures of 1–4 have been discussed. The electrochemical behaviors of 1 and 2, the thermal stabilities and fluorescent properties of 1–4, and the fluorescent selectivities of 3 and 4 have been investigated. Four new metal–organic coordination polymers have been hydrothermally synthesized by the flexible bis-pyridyl-bis-amide ligands and two different aromatic dicarboxylates. The influences of the different dicarboxylates and central metal ions on the structures of 1–4 have been reported. Moreover, the electrochemical behaviors of 1 and 2, thermal stabilities, and the fluorescent properties of 1–4 have been investigated.

A novel polyoxometalate templated microporous metal–organic framework with electrochemical properties

A novel Wells–Dawson polyoxometalate-templated 3D microporous metal–organic framework (MOF), namely, H6[Cu3(H2O)6(P2W18O62)2(3-dpye)6]·28H2O (1) (3-dpye = N,N′-bis(3-pyridinecarboxamide)-1,2-ethane), was hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR spectra, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Each Cu(II) ion acts as a four-connected node linking four 3-dpye ligands to construct a 3D microporous host MOF containing left-handed helical chains, in which the P2W18O626− anions reside. 1 represents the first example of 3D MOFs with an 86 uniform net containing non-coordinating Wells–Dawson anions. The electrochemical properties have been investigated in detail.

Substituent position-induced diverse architectures of polyoxovanadate-based hybrid materials constructed from a linear trinuclear transition metal complex and a hexanuclear [V6O18]6- cluster

Four new hexavanadate cluster-based hybrid materials [Ni(3-atrz)2V2O6]·2H2O (1) and [M3(4-atrz)6V6O18]·4H2O [atrz = amino-1,2,4-triazole; M = Ni (2), Co (3) and Zn (4)] have been synthesized under hydrothermal conditions by the reaction of transition metal salts, amino-triazole ligands and sodium metavanadate. Single crystal X-ray diffraction analyses reveal that compound 1 shows a one-dimensional (1D) chain formed by the alternative arrangement of linear trinuclear complexes [Ni3(3-atrz)6]6+ and hexanuclear [V6O18]6− clusters. Compounds 2–4 are isostructural three-dimensional (3D) frameworks, which are constructed from the linear trinuclear transition metal complexes and 2D inorganic layers derived from transition metal ions and hexanuclear [V6O18]6− clusters. The distinct amino positions in the two types of triazole ligands play the key role in determining the final dimensionality and structures of the title compounds. The thermal stability, photocatalytic activity and magnetic properties of 1–4 have been investigated.

Aromatic Polycarboxylate-Tuned Assembly of Three New 2D Copper(II) Complexes Derived from a Flexible Bis(pyridylamide) Ligand

Three new 2D copper(ii) complexes [Cu(NIPH)(L)] (1), [Cu(BDC)(L)(H2O)] (2), and [Cu(HBTC)(L)]·2H2O (3) were hydrothermally synthesized by self-assembly of aromatic polycarboxylates (H2NIPH = 5-nitroisophthalic acid, H2BDC = 1,3-benzenedicarboxylic acid, H3BTC = 1,3,5-benzenetricarboxylic acid) and the flexible bis(pyridylamide) ligand L (L = N,N′-di(3-pyridyl)succinamide), and structurally characterized by single crystal X-ray diffraction, and elemental, IR, and thermogravimetric analyses. Compound 1 is a 2D coordination polymer based on tri-flexural helix chains (left-, right-handed [Cu-L]n helix chains, and left-handed Cu-NIPH helix chain). Compound 2 exhibits a 2D wavelike polymeric layer structure constructed from a 1D [Cu-L]n sinusoidal chain and a 1D [Cu-BDC]n V-like chain. Compound 3 possesses a 2D double-layer network formed from 1D [Cu-L]n zigzag chains and 1D [Cu-HBTC]2n double chains. The fluorescent properties of the three compounds and the electrochemical behaviour of compound 2-bulk-modified carbon paste electrode were also studied.

Assembly, structures, photophysical properties and photocatalytic activities of a series of coordination polymers constructed from semi-rigid bis-pyridyl-bis-amide and benzenetricarboxylic acid

A series of new metal(II)–organic coordination polymers, namely [Co(3-DPNA)(1,3,5-HBTC)]·2H2O (1), [Ni(3-DPNA)1.5(1,3,5-HBTC)(H2O)2] (2), [Cu(3-DPNA)(1,3,5-HBTC)]·H2O (3), [Zn(3-DPNA)(1,3,5-HBTC)]·2H2O (4), [Cd(3-DPNA)(1,3,5-HBTC)(H2O)]·2H2O (5), [Co(4-DPNA)(1,3,5-HBTC)]·4H2O (6), [Ni(4-DPNA)(1,3,5-BTC)2/3] (7), [Cu(4-DPNA)(1,3,5-BTC)2/3] (8), [Zn(4-HDPNA)(1,3,5-BTC)] (9), [Cd(4-DPNA)(1,3,5-BTC)1/3Cl] (10), have been purposefully synthesized under hydrothermal conditions [N1,N4-di(pyridin-3-yl)naphthalene-1,4-dicarboxamide (3-DPNA) and N1,N4-di(pyridin-4-yl)naphthalene-1,4-dicarboxamide (4-DPNA), 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid]. Complexes 1 and 4 exhibit similar 1D belt-like chains constructed from 1D left- and right-hand [Co-(3-DPNA)]n helical chains and [Co-(1,3,5-HBTC)]n linear chains. Complex 2 furnishes a 1D [Ni-(3-DPNA)1.5]n “loop + line” chain with 1,3,5-HBTC anions hanging on both sides. Complex 3 features a 2D sql network based on [Cu-(3-DPNA)]nmeso-helical chains and [Cu-(1,3,5-HBTC)]n linear chains. Complex 5 shows a 1D ladder-like chain constructed from [Cd-1,3,5-HBTC]n linear chains and [Cd2(3-DPNA)2] loops. Complex 6 displays a 2D double sheet containing (H2O)8 clusters. Complexes 7 and 8 possess similar 3D (3,4)-connected frameworks with the (63)2(64·8·10)3 topology containing a dodecagon-shape cavity and a hexagonal cavity, respectively. Complex 9 shows a 2D network, in which one pyridine nitrogen atom of 4-DPNA was protonated. Complex 10 is a 3D (3,5)-connected framework with (3·44·63·82)3(63) topology. All the 1D chains and 2D networks are further extended into 2D supramolecular sheets or 3D supramolecular frameworks through hydrogen-bonding interactions. The influence of metal(II) ions and N-donor ligands on the structures of the title compounds was investigated. The results suggest that the central metals with various coordination nature and the semi-rigid bis-pyridyl-bis-amide ligands with different coordination sites show a great effect on the structures of the title compounds. In addition, the fluorescence sensing properties of 4, 5, 9, and 10 and the photocatalytic activities of complexes 1–10 have been investigated in detail, and the results show that 5 possesses good fluorescence selectivity for different solvent molecules.