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Two series of copper-lanthanide heterometallic coordination polymers (CPs), [LnCu(2,3-pydc)2(suc)0.5(H2O)3]·H2O [Ln = La (I), Pr (II), Nd (III), Sm (IV), Gd (V), and Eu (VI), 2,3-H2pydc = pyridine-2,3-dicarboxylic acid, H2suc = succinic acid], [Ln2Cu3(2,3-pydc)6(H2O)10]·8H2O [Ln = Eu (VII), Tb (VIII), Dy (IX), and Er (X)], [Ln2Cu(2,3-pydc)2(suc)(μ2-OH)2(H2O)2]·2H2O [Ln = Er (XI), Yb (XII), and Lu (XIII)], [Ln2Cu(2,3-pydc)2(suc)2(H2O)6]·2H2O [Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), and Er (6)], and Ln2Cu(2,3-pydc)2(suc)2(H2O)2 [Ln = Er (7), Yb (8), and Lu (9)], were successfully synthesized by the hydrothermal reactions of Cu(NO3)2·3H2O, LnCl3·nH2O, 2,3-H2pydc, and H2suc. CPs 1–9 show two types of similar two-dimensional (2D) structures. In 1–9, the 2,3-pydc anions bridge the CuII ions into a one-dimensional (1D) loop chain, and the suc anions link the LnIII ions into a 1D double chain. The 1D loop chains and the 1D double chains connect each other to generate a 2D layer. The adjacent 2D layers are further packed into a three-dimensional (3D) supramolecular architecture by hydrogen-bonding interactions. CPs 4 and 6 display ferromagnetic interactions between the paramagnetic centers, and CP 5 shows a field-induced slow magnetic relaxation behavior. The structures and magnetic properties of I–XIII have been reported in previous work (Eur. J. Inorg. Chem., 2016, 1060).

Two bis-triazole-bis-amide-based copper(II) pyridine-2,3-dicarboxylate coordination polymers (CPs), [Cu(2,3-pydc)(dtb)0.5(DMF)]·2H2O (1) and [Cu(2,3-pydc)(dth)0.5(DMF)]·2H2O (2) (2,3-H2pydc = pyridine-2,3-dicarboxylic acid, dtb = N,N′-bis(4H-1,2,4-triazole)butanamide, and dth = N,N′-bis(4H-1,2,4-triazole)hexanamide), were synthesized under solvothermal conditions. CPs 1 and 2 show similar two-dimensional (2D) structures. In 1, the 2,3-pydc anions bridge the CuII ions into a one-dimensional (1D) chain. Such 1D chains are linked by the dtb ligands to form a 2D layer. The adjacent 2D layers are extended into a three-dimensional (3D) supramolecular architecture by hydrogen-bonding interactions. The electrochemical properties of 1 and 2 were investigated.

Six copper–lanthanide heterometallic coordination polymers (CPs) [LnCu(2,3-pydc)2(HCOO)(H2O)3]·H2O [Ln = La (1), Pr (2), Nd (3), Sm (4), Eu (5), and Gd (6), 2,3-H2pydc = pyridine-2,3-dicarboxylic acid] were synthesized successfully by the reactions of 2,3-H2pydc with LnCl3·nH2O and Cu(NO3)2·3H2O under solvothermal conditions of H2O–DMF or H2O–DMF–MeOH. They were structurally characterized by single-crystal X-ray diffraction and powder X-ray diffraction (PXRD). CPs 1–6 possess isostructural 2D (4,4) layer architectures built from the dinuclear Ln2(HCOO)2 and Cu2(2,3-pydc)4 units. The reaction solvents have an important effect on the formation of 1–6. The electrochemical properties of 1–6 were investigated.

A series of copper–lanthanide heterometallic coordination polymers (CPs), [LnCu(2,3-pydc)2(suc)0.5(H2O)3]·H2O [Ln = La (1), Pr (2), Nd (3), Sm (4), Gd (5), and Eu (6), 2,3-H2pydc = pyridine-2,3-dicarboxylic acid, H2suc = succinic acid], [Ln2Cu3(2,3-pydc)6(H2O)10]·8H2O [Ln = Eu (7), Tb (8), Dy (9), and Er (10)], and [Ln2Cu(2,3-pydc)2(suc)(µ2-OH)2(H2O)2]·2H2O [Ln = Er (11), Yb (12), and Lu (13)], were synthesized by the hydrothermal reactions of LnCl3·nH2O, Cu(NO3)2·3H2O, pyridine-2,3-dicarboxylic acid (2,3-H2pydc), and N,N′-di(4H-1,2,4-triazole)butanamide (dtb). CPs 1–13 possess three types of three-dimensional (3D) frameworks. In 1–6, the dinuclear Cu2(2,3-pydc)4 and Ln2(COO)2 units link to each other to form two-dimensional (2D) layers, which are extended by the suc anions into a 3D framework. In 7–10, the lanthanide ions connect the trinuclear Cu3(2,3-pydc)6 units into a 3D framework. In 11–13, the mononuclear Cu(2,3-pydc)2 units bridge the one-dimensional (1D) lanthanide chains into 2D layers, which are linked by the suc anions into a 3D framework. CP 9 shows a field-induced slow magnetic relaxation behavior with a Ueff value of 83.7 K.

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.

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.

Seven new coordination polymers, namely, [Ni(L)1.5(2-CMSN)(H2O)]·2H2O 1, [Co2(L)2(2-CMSN)2(H2O)]·H2O 2, [Cd(L)(2-CMSN)(H2O)] 3 [Zn(L)(2-CMSN)]·2H2O 4, [Cd(ADTZ)(H2O)] 5, [Cd(L)(ADTZ)(H2O)] 6, and [Zn(L)(ADTZ)]·H2O 7 [where 2-H2CMSN = 2-carboxymethylsulfanyl nicotinic acid, H2ADTZ = 2,5-(s-acetic acid) dimercapto-1,3,4-thiadiazole, L = 1,4-bis(imidazol-1-ylmethyl)benzene] have been synthesized under hydrothermal conditions. The complexes were structurally characterized by single crystal X-ray diffraction analyses, infrared spectroscopy (IR), elemental analyses, powder X-ray diffraction (PXRD) and thermogravimetric analyses (TGA). Complex 1 features a 1D ladder-like double chain. Complexes 2 and 3 exhibit the similar 2D networks based on six-nuclear metallic rings. Complex 4 is a 2D sheet. Complex 5 exhibits a 3D (4,6)-connected (43·53)(45·53·67) topology. Complex 6 shows a 2D undulated network with the Schlafli symbol of (3·52)(32·53·64·7). Complex 7 is a 3D 4-fold interpenetrated dia network. Structural comparison of these polymers suggests that different central metals and dicarboxylates play important roles in the construction of 1–7. The luminescent properties of complexes 3, 4, 6, 7 and the electrochemical properties of complexes 1, 2 have been investigated. Furthermore, the complexes 2–4, 6 and 7 exhibit photocatalytic activities for dye methylene blue degradation under UV light and show good stability toward photocatalysis.

Four CoII/MnII coordination compounds, namely, [Co(dpq)(L1)(H2O)1.5] (1), [Co(dpq)(L2)(H2O)2]·H2O (2), [Mn2(dpq)2(L2)2]·2H2O (3), and [Mn(dpq)(L3)] (4) [H2L1 = 5-methylisophthalic acid, H2L2 = 5-hydroxyisophthalic acid, and H2L3 = bis(sulfanediyl) thiadiazole diacetic acid] were obtained from hydrothermal reactions of dipyrido [3,2-d:2′,3′-f]quinoxaline (dpq) and three structurally related mixed dicarboxylate ligands. Single crystal X-ray diffraction analysis reveals that compound 1 consists of a dinuclear CoII cluster linked by two carboxylate groups from different L1 anions and a coordination water molecule. Compound 2 is a dimeric structure based on a pair of L2 anions and two CoII ions. Both compounds are finally extended into three dimensional (3D) supramolecular networks by hydrogen bonding and π–π stacking interactions. In compound 3, two MnII ions are linked by a pair of carboxylate groups to form a bimetallic unit, which is extended by pairs of L2 anions to generate a 1D wave-like band. The adjacent bands are linked by hydrogen bonding interactions forming a 2D supramolecular architecture. Compound 4 is a (4,4)-connected 2D network based on L3 linkers and dinuclear MnII units connected by two carboxylate groups. The effects of metal ions and dicarboxylates with different spacers on the architectures of the title compounds were discussed. Moreover, the electrochemical behavior of compounds 1 and 2, magnetic properties of compounds 1, 3, and 4, and photoluminescent properties of compounds 1–4 were investigated.

A three-dimensional (3D) homochiral metal-organic coordination polymer with a 6-connected 412.63 topology was synthesized hydrothermally, Cd4(D-cam)4(bbbm)2 (1) [D-H2cam = D-(+)-camphoric acid and bbbm = 1,1-(1,4-butanediyl)bis-1H-benzimidazole], which represents the first example of metal-camphorate coordination polymers constructed from two types of dinuclear cadmium clusters [Cd2(O2C–)4] and a flexible bis(benzimidazole)-based ligand. The thermal and photoluminescent properties of 1 were investigated.

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.

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.