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A new series of five zinc(ii) coordination polymers was assembled from unexplored ether-bridged tetracarboxylate linkers and fully characterized.

In contrast to the broad use of terephthalic acid as a building block for generating metal-organic architectures, functionalized terephthalate ligands remain significantly less investigated. In the present study, 2-chloroterephthalic acid (CltaH2) was used as an unexplored linker for assembling a new series of metal(II) coordination polymers (CPs) formulated as {[Cu2(μ-Clta)(μ4-Clta)(bipy)2]·2H2O}n (1), {[Cu2(μ-Clta)(μ4-Clta)(phen)2]·2H2O}n (2), [Co3(μ4-Clta)3(phen)2]n (3), {[Zn4(μ3-Clta)2(μ4-Clta)(μ3-OH)2(phen)2]·2H2O}n (4), {[Cd(μ3-Clta)(phen)]·H2O}n (5), [Co2(μ-Clta)(μ4-Clta)(μ-bpa)2]n (6), [Zn2(μ4-Clta)(μ4-biim)]n (7), and [Cd(μ-Clta)(H2biim)2]n (8). These compounds were prepared hydrothermally from the respective metal(II) chlorides, CltaH2, and different N-donor supporting ligands acting as mediators of crystallization (i.e., bipy, 2,2′-bipyridine; phen, 1,10-phenanthroline; bpa, bis(4-pyridyl)amine; H2biim, 2,2′-biimidazole). The structures of the coordination polymers 1-8 range from one-dimensional chains (5 and 8) and two-dimensional layers (1-3) to three-dimensional (3D) frameworks (4, 6, and 7); the latter also include 3D + 3D interpenetrated examples (4, 6). Apart from different dimensionalities, the compounds also feature distinct topologies, namely, 3,4L13 in 1 and 2, 3,4,6L12 in 3, pcu in 4, SP 1-periodic net (4,4)(0,2) in 5, sqc65 in 6, 2C1 in 8, and a new kir1 topology in 7. Given the similarity of the reaction conditions, the obtained wide diversity of structures is primarily determined by the type of metal(II) node and/or crystallization mediator. All the CPs were also screened as heterogeneous catalysts in a model CO2 fixation reaction, namely, in the coupling of epoxide (epichlorohydrin) with carbon dioxide, under atmospheric pressure, and in the absence of added solvent, to produce the corresponding cyclic carbonate. The catalytic reactions were optimized for CP 4, which revealed the best activity (up to 71% product yields), good stability, and recyclability for up to four reaction steps. Finally, CPs 3-8 are the first examples of cobalt, zinc, and cadmium coordination compounds assembled from 2-chloroterephthalic acid, thus widening its very limited application in the design of functional metal-organic architectures. ©

A novel biphenyl-tricarboxylic acid, 3,2′,4′-biphenyl-tricarboxylic acid (H3bta), was used as a versatile linker for preparing a new series of nickel(II), zinc(II), and cadmium(II) coordination polymers (CPs) and complexes, formulated as {[Cd(μ-Hbta)(2,2′-bipy)(H2O)]·3H2O}n (1), {[Ni(μ-Hbta)(4,4′-bipy)(H2O)3]·H2O}n (2), [M2(μ-Hbta)2(4,4′-bipy)2(H2O)2]·2H2O (M = Zn (3) and Cd (4)), {[Cd2(μ4-bta)(μ-Cl)(phen)2]·2H2O}n (5), {[Zn2(μ3-bta)(2,2′-bipy)2(H2O)3][Zn(μ-bta)(2,2′-bipy)(H2O)]·3H2O} (6), {[Cd3(μ4-bta)2(2,2′-bipy)3]·4H2O}n (7), {[Zn3(μ3-bta)2(H2biim)2(μ-H2biim)(H2O)2]·2H2O}n (8), and [Zn3(μ6-bta)2(py)2]n (9). These coordination compounds were hydrothermally assembled from the metal(II) chlorides, H3bta as a principal building block and N-donor ancillary ligands as crystallization mediators (i.e., 2,2′-bipyridine, 2,2′-bipy; 4,4′-bipyridine, 4,4′-bipy; 1,10-phenanthroline, phen; 2,2′-biimidazole, H2biim; or pyridine, py). All the synthesized products 1–9 were characterized by standard solid-state methods including elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. The structures of 1–9 range from 0D dimers (3 and 4) to 1D coordination polymers (1, 2, 5, and 6) and 2D metal–organic layers (7–9). Such a diversity of structures is explained by the differences in metal(II) centers, deprotonation levels of H3bta, and crystallization mediators. From a topological perspective, the obtained structures include 2C1 chains (in 1, 2, and 6), pcu H-bonded nets (in 3 and 4), SP 1-periodic nets (in 5), and 4,5L51 (in 7) and hcb (in 8) layers. For compounds 1–9, luminescence properties were also evaluated. Besides, the catalytic behavior of the obtained products was screened in the cyanosilylation of benzaldehydes with trimethylsilyl cyanide to give cyanohydrin products under mild conditions, including an optimization of various reaction parameters and an investigation of the substrate scope. Among the tested compounds, 3 acts as the most efficient and recyclable heterogeneous catalyst with up to 96% product yields. By presenting the unique examples of coordination compounds derived from H3bta, this study introduces its use as a new tricarboxylate linker for assembling functional coordination polymers and metal complexes.

A triphenyl-pentacarboxylic acid, 3,5-di(2′,4′-dicarboxylphenyl)benzoic acid (H5ddba), was applied as an adaptable linker for the hydrothermal assembly of eight new metal(II) coordination polymers (CPs) and complexes, formulated as [Cu2(μ-H3ddba)2(phen)2] (1), {[Cd2(μ4-Hddba)(phen)2(H2O)2]·2H2O}n (2), [M4(μ3-Hddba)2(2,2′-bipy)6(μ-H2O)]·6H2O (M = Ni (3), Mn (4)), {[Co2(μ5-Hddba)(μ-4,4′-bipy)1.5(H2O)]·H2O}n (5), {[Zn2(μ5-Hddba)(4,4′-bipy)1.5]·4,4′-bipy·2H2O}n (6), [Mn2(μ6-Hddba)(H2biim)(H2O)]n (7), and {[Cd2(μ7-ddba)(Hbpa)]·5H2O}n (8). The products 1–8 were generated from metal(II) chlorides, H5ddba, and various N-donor supporting ligands acting as mediators of crystallization (i.e., phen: 1,10-phenanthroline; 2,2′-bipy: 2,2′-bipyridine; 4,4′-bipy: 4,4′-bipyridine; H2biim: 2,2′-biimidazole; or bpa: bis(4-pyridyl)amine). All compounds were analyzed by standard methods (C/H/N analysis, FTIR, TGA and PXRD) including single-crystal X-ray diffraction. The structural multiplicity of 1–8 ranges from discrete dimers (1) or tetramers (3 and 4) to a 1D coordination polymer (2) and 3D metal–organic frameworks (5–8). Topological analysis of simplified H-bonded or metal–organic networks disclosed fcu (1), 2C1 (2), dia (3 and 4), sra (6), 3,4,7T3 (8), and unprecedented (5 and 7) topologies. The catalytic activity of 1–8 was investigated in a model Knoevenagel condensation between benzaldehydes and malononitrile, resulting in up to 99% yields of condensation products. The substrate scope, catalyst recycling, and effects of different reaction parameters were investigated. Finally, this work extends the use of H5ddba as an aromatic pentacarboxylate building block for the design of new metal–organic architectures with captivating structures and functional properties.

This work describes the application of an unexplored aromatic tetracarboxylate building block, 2,3′,4,4′-diphenyl ether tetracarboxylic acid (H4deta), for the synthesis of manganese(II) and cadmium(II) coordination polymers (CPs). Five new products, formulated as [Mn2(μ6-deta)(phen)2]n (1), [Cd2(μ6-deta)(phen)2]n (2), [Mn2(μ6-deta)(2,2′-bipy)2]n (3), [Cd2(μ5-deta)(4,4′-bipy)2(H2O)2]n·2nH2O (4), and [Cd2(μ6-deta)(py)(H2O)2]n (5), were assembled using a hydrothermal protocol from the respective metal(II) chlorides, H4deta, and different mediators of crystallization, namely 1,10-phenanthroline (phen), 2,2′-bipyridine (2,2′-bipy), 4,4′-bipyridine (4,4′-bipy), or pyridine (py). All the CPs 1–5 were obtained as stable crystalline products and characterized by conventional solid-state methods (elemental analysis, FTIR, UV-vis, TGA, and PXRD) and single-crystal X-ray diffraction. The structures of 1–3 feature decorated honeycomb-like 2D double layers of a 3,6L66 topological type. Compound 4 reveals a trinodal 4,4,5-connected 3D metal–organic framework (MOF) with a unique topology, while the 2D coordination polymer 5 discloses a binodal 4,6-connected layer with a 4,6L45 topology. The structural and topological traits, thermal stability, luminescence properties and photocatalytic activity toward methylene blue degradation were studied for the obtained compounds. In particular, MOF 4 acts as an active, stable, and recyclable photocatalyst for the UV-light-assisted discoloration of methylene blue in water under ambient conditions. By introducing a novel type of flexible tetracarboxylic acid linker, the present study discloses the first manganese and cadmium compounds derived from H4deta as an unexplored polycarboxylate building block, thus contributing to intensive research on functional metal–organic architectures.

New coordination polymers of cobalt(II), namely, [Co(μ4-cpna)(H2O)2]n (1), [Co(μ3-cpna)(phen)(H2O)]n·nH2O (2), [Co3(μ4-dppa)2(H2O)6]n·2nH2O (3), and [Co3(μ5-dppa)2(μ-4,4′-bipy)(H2O)2]n·4nH2O (4), h...

An aromatic tricarboxylic acid, 4-(6-carboxy-pyridin-3-yl)-isophthalic acid (H3cpia), was applied as a building block for the hydrothermal syntheses of a new series of twelve metal(II) (M = Mn, Co, Ni, Zn, Cd, Pb) coordination compounds, namely [Mn(H2cpia)2(H2O)2] (1), [M(Hcpia)(phen)(H2O)2] (M = Co, 2; Ni, 3; Zn, 4), [Zn(Hcpia)(2,2′-bipy)(H2O)2]5·4H2O (5), [Zn2(μ-Hcpia)2(2,2′-bipy)2] (6), [M(μ-Hcpia)(phen)(H2O)]n (M = Co, 7; Cd, 8), {[Pb(μ4-Hcpia)]·2H2O}n (9), [Cd4(μ3-cpia)2Cl2(phen)6(H2O)2]·10H2O (10), {[Zn3(μ3-cpia)2(phen)3]·10H2O}n (11), and {[Zn4(μ4-cpia)2(μ-OH)2(μ-4,4′-bipy)2]·4,4′-bipy·2H2O}n (12). These products were assembled from aqueous mixtures containing metal(II) chlorides, H3cpia as a main tricarboxylic acid block, sodium hydroxide and an optional N-donor crystallization mediator (i.e., 1,10-phenanthroline, phen; 2,2′-bipyridine, 2,2′-bipy; or 4,4′-bipyridine, 4,4′-bipy). Compounds 1–12 were fully characterized by standard solid-state methods (IR spectroscopy, elemental analysis, TGA, PXRD, and single-crystal X-ray diffraction). Their structures range from discrete 0D monomers (1–5), dimer (6) or tetramer (10) to 1D coordination polymers (7, 8, and 11) and 2D metal–organic layers (9 and 12). Structural and topological features of H-bonded and metal–organic architectures were highlighted, showing that the structural diversity of 1–12 is influenced by the type of metal(II) node, the level of deprotonation of H3cpia, reaction temperature, and presence of crystallization mediator. Thermal behavior, magnetic, luminescent and photocatalytic properties of selected compounds were investigated and discussed. In fact, cobalt(II) coordination polymer 7 acts as a stable and recycable photocatalyst for the oxidative UV-light-assisted degradation of an organic dye in aqueous medium; methylene blue was used as a model dye pollutant in waste water. Finally, the obtained products 2 and 4–12 represent the first examples of Co, Zn, Cd, and Pb coordination compounds derived from H3cpia, thus introducing its application as a multifunctional picolinate-isophthalate building block for the generation of metal–organic architectures.

Two new cadmium(II)-based materials, featuring two-dimensional (2D) [Cd2(&mu, 6-deta)(bpy)(H2O)]n (1) and three-dimensional (3D) [Cd2(&mu, 5-deta)(bpy)2(H2O)]n (2) structures, were constructed by the hydrothermal method from 2,3&prime, 4&prime, 5-diphenyl ether tetracarboxylic acid (H4deta) as an unexplored linker in research on coordination polymers (CPs) and 2,2&prime, bipyridine (bpy) as a mediator of crystallization. Microcrystalline samples of 1 and 2 were analyzed by IR/PXRD/EA/TGA and X-ray diffraction using single crystals. Structures and topologies of CPs 1 and 2 were established, revealing a 4,6L45 topological layer in 1 and a 3,5T1 topological framework in 2. Structural differences for 1 and 2 are attributed to distinct molar ratios between Cd2+ and bpy during the hydrothermal synthesis. Luminescence and thermal behavior of the obtained materials were also investigated. The present work opens up the use of an unexplored 2,3&prime, 5-diphenyl ether tetracarboxylic acid as a versatile and flexible linker toward the generation of functional coordination polymer materials.

Three new 2D lanthanide-organic networks, {[Sm-2(mu(4)-cpta)(mu(5)-cpta)(H2O)(3)]center dot 3H(2)O}(n) (1) and [Ln(mu(3)-cpta)(phen)(H2O)(2)](n) (Ln = Tb (2) and Sm (3)), were successfully synthesized via hydrothermal reactions using Ln(NO3)(3)center dot 6H(2)O, a flexible ether-bridged tricarboxylic acid H(3)cpta (2-(2-carboxyphenoxy)terephthalic acid) as a principal building block, and phen (1,10-phenanthroline) as an optional supporting ligand. All products were obtained as air and thermally stable microcrystalline solids and fully characterized by standard solid-state techniques, including elemental analysis, TGA, IR spectroscopy, powder and single-crystal X-ray diffraction. Compound 1 possesses an intricate 2D layer structure with the 4,5L51 topology, which is driven by the mu(4)- and mu(5)-cpta(3) and Sm(III) nodes. Compounds 2 and 3 are isostructural and disclose a different 2D metal-organic network with the fes topology, which is assembled from the mu(3)-cpta(3) and Ln(III) nodes. Luminescence properties of 2 and derived M(n+)2 suspensions were investigated, disclosing a possible use of this compound as a notable luminescence sensor for the detection of Fe3+ cations in aqueous medium. (C) 2017 Elsevier B.V. All rights reserved.

5-(3,4-Dicarboxylphenyl)picolinic acid (H3dppa) was applied as a novel tricarboxylic acid block with phthalate and picolinate functionalities for the aqueous-medium assembly of seven new coordination compounds, namely, [Mn2(μ-Hdppa)2(phen)2(H2O)2] (1), {[Mn(μ-Hdppa)(2,2′-H2biim)(H2O)]·H2O}n (2), [Ni(Hdppa)(phen)2]·4H2O (3), {[Ni(μ-Hdppa)(μ-4,4′-bipy)(H2O)]·H2O}n (4), {[Cu3(μ3-dppa)(μ-Hdppa)(phen)4]2[Cu(μ-Hdppa)2]·10H2O}n (5), {[Ni3(μ-dppa)2(μ-1,4-bpb)2(H2O)6]·4H2O}n (6), and {[Zn3(μ4-dppa)2(phen)2(H2O)2]·4H2O}n (7). These products 1–7 represent the first structurally characterized examples of the coordination compounds derived from H3dppa. Compounds 1–7 were assembled in the presence of various N-donor supporting ligands acting as crystallization mediators, which were selected from 1,10-phenanthroline (phen), 2,2′-biimidazole (H2biim), 4,4′-bipyridine (4,4′-bipy), or 1,4-bis(pyrid-4-yl)benzene (1,4-bpb). Full characterization of 1–7 by IR spectroscopy, thermogravimetric (TGA), elemental, and topological analyses, as well as powder (PXRD) and single-crystal X-ray diffraction, was performed. The structural types range from the discrete 0D complexes (1 and 3) and 1D coordination polymers with a 2C1 topology (2, 5, and 6) to the 2D metal–organic layers with an sql topology (4 and 7). The structural diversity of 1–7 is driven by various factors, including the metal(II) node nature, deprotonation degree of H3dppa, or type of crystallization mediator. The magnetic properties of 1, 2, 4, and 6 were studied and modeled, revealing antiferromagnetic (in 1, 2, and 6) or ferromagnetic (in 4) interactions between adjacent metal(II) centers. The luminescence of 7 was also investigated. Moreover, the photocatalytic activity of 1–7 was studied for the degradation of methylene blue as a model dye pollutant, disclosing that the nickel(II) coordination polymer 4 is the most active catalyst. The observed catalytic activity of 1–7 correlates well with their band gap energies determined by the UV-diffuse reflectance method.

Biphenyl-2,5,3′-tricarboxylic acid (H3L) was selected as an unexplored tricarboxylate building block and applied for the hydrothermal synthesis of three novel coordination compounds, namely a 0D tetramer [Co4(HL)2(μ3-HL)2(phen)6(H2O)2]·3H2O (1) and two 3D metal-organic frameworks (MOFs) [Cd3(μ5-L)(μ6-L)(py)(μ-H2O)2(H2O)]n·H2O (2) and [Zn3(μ4-L)2(2,2′-bpy)(μ-4,4′-bpy)]n·2H2O (3). These products were easily generated in aqueous medium from the corresponding metal(II) chlorides, H3L, and various N-donor ancillary ligands, selected from 1,10-phenanthroline (phen), pyridine (py), 2,2′-bipyridine (2,2′-bpy), and 4,4′-bipyridine (4,4′-bpy). Compounds 1–3 were isolated as stable crystalline solids and were fully characterized by IR and UV–vis spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a discrete tetracobalt(II) structure, which is extended into a 3D H-bonded network with the pcu topology. In contrast, MOF 2 discloses a very complex trinodal 4,5,12-connected net with an undocumented topology, while MOF 3 features the nce/I topological framework. The magnetic (for 1) and luminescence (for 2 and 3) properties were also studied and discussed. The present study thus widens a still very limited family of metal-organic and supramolecular frameworks driven by flexible biphenyl-2,5,3′-tricarboxylate building blocks.

4-(3-Carboxyphenyl)picolinic acid (H2cppa) was applied as a new and virtually unexplored building block for the synthesis of eleven new coordination compounds, namely [M(Hcppa)2(H2O)2]·2H2O {M = Ni (1) and Zn (2)}, [M(μ3-cppa)(H2O)2]n {M = Ni (3) and Co (4)}, {[Co(μ-cppa)(2,2′-bipy)(H2O)]·H2O}n (5), [Zn(μ-cppa)(2,2′-bipy)]n (6), [M(μ-cppa)(phen)(H2O)]n {M = Co (7), Zn (8), Mn (9), and Cu (10)}, and {[Cd3(μ3-cppa)3(phen)2]·4H2O}n (11). All these compounds were generated by a hydrothermal self-assembly method using the corresponding metal(II) chlorides, H2cppa, and two types of N-donor ancillary ligands, selected from 2,2′-bipyridine (2,2′-bipy) or 1,10-phenanthroline (phen). The obtained products 1–11 were characterized by standard methods, including IR spectroscopy, elemental and thermogravimetric analyses, and powder and single-crystal X-ray diffraction. They represent the first structurally characterized compounds derived from H2cppa. The structures of 1–11 vary from a complex 3D metal–organic framework (MOF) 11 to 2D coordination polymers 3 and 4, 1D coordination polymers 5–10, and discrete 0D monomers 1 and 2. Such a structural diversity is guided by the nature of the metal(II) node, level of deprotonation of 4-(3-carboxyphenyl)picolinic acid, and type of applied ancillary ligand. In addition, the structures of 1, 2, 5, and 7–10 are further extended [0D → 3D (1 and 2), 1D → 2D (5), and 1D → 3D (7–10)] into various H-bonded supramolecular networks. Both the supramolecular (in 1, 2, 5, and 7–10) and metal–organic (in 3, 4, 6, and 11) underlying networks were analyzed and classified from the topological viewpoint, revealing the distinct pcu (in 1 and 2), fes (in 3 and 4), gek1 (in 5), 2C1 (in 6), and srs (in 7–10) topological nets, whereas a topologically unique framework was identified in MOF 11. The magnetic behavior of 3–5, 7, 9, and 10 and luminescence properties of 2, 6, 8, and 11 were also investigated and discussed.

In this work, a trifunctional N,O-building block, 5-(4-carboxyphenoxy)nicotinic acid (H2cpna), that combines three distinct types of functional groups (COOH, N-pyridyl, and O-ether) was used for the hydrothermal assembly of thirteen new coordination compounds: [Co(μ3-Hcpna)2]n (1), [Mn(μ4-cpna)(H2O)]n (2), [Mn(μ4-cpna)(H2O)2]n (3), [Mn(μ-cpna)(2,2'-bipy)(H2O)2]n (4), {[Ni(μ3-cpna)(2,2'-bipy)(H2O)]2·H2O}n (5), {[Cd(μ3-cpna)(2,2'-bipy)]·2H2O}n (6), [Zn2(μ-cpna)2(2,2'-bipy)2] (7), [Cu(μ-cpna)(2,2'-bipy)(H2O)]n (8), {[Mn(μ-cpna)(phen)2]·6H2O}n (9), {[Ni(μ3-cpna)(phen)(H2O)]·H2O}n (10), [Zn2(μ-cpna)2(phen)2] (11), {[Pb(μ3-cpna)(phen)]·H2O}n (12), and [Ni(μ3-cpna)(4,4'-bipy)0.5(H2O)]n (13). These products were synthesized from the corresponding metal(ii) chlorides, H2cpna, NaOH, and optional N-donor supporting ligands or templates {bis(4-pyridyl)amine (bpa), 2,2'-bipyridine (2,2'-bipy), 4,4'-bipyridine (4,4'-bipy), or 1,10-phenanthroline (phen)}. Products 1-13 were characterized in the solid state by standard methods, including elemental and thermogravimetric analysis (TGA), IR spectroscopy, and powder (PXRD) and single-crystal X-ray diffraction. The structures of 1-13 feature distinct structural types, namely the 3D metal-organic frameworks (MOFs 1-3), the 2D coordination polymers (5, 6, 10, 12, and 13), the 1D coordination polymers (4, 8, and 9), and the 0D discrete cyclic dimers (7 and 11). Such a wide structural diversity of 1-13 is driven by various factors, including the type of the metal(ii) node, the deprotonation degree of H2cpna, and/or the type of supporting ligand or template. Notably, an addition of bpa can tune the structure of MOF 3 by the template effect. Topological classification of underlying metal-organic networks was performed, leading to several distinct topological nets: rtl (in 1), hxg-d-4-C2/m (in 2), sra (in 3), 2C1 (in 4, 8 and 9), fes (in 5, 10, and 12), hcb (in 6), and 3,4L83 (in 13). The magnetic behavior of 1-5, 8-10, and 13 was studied and theoretically modeled, disclosing antiferromagnetic interactions. The luminescence behavior of 6, 7, 11, and 12 was also investigated.

In this work, an ether-bridged aromatic carboxylic acid, 2-(2-carboxyphenoxy)terephthalic acid (H3cpta), was applied as an unexplored building block for the generation of a novel series of coordination compounds, which represent the first examples of structurally characterized products derived from H3cpta, thus opening up its use as a versatile building block in crystal engineering research. The obtained products were formulated as [Cd(μ-Hcpta)(phen)(H2O)]n (1), [Mn(μ-Hcpta)(phen)(H2O)]n (2), {[Cd3(μ3-Hcpta)(μ4-cpta)(μ-Cl)(H2O)4]·2H2O}n (3), {[Cd3(μ6-cpta)2(py)2]·5H2O}n (4), [Mn3(μ5-cpta)2(2,2′-bipy)2]n (5), [Mn3(μ4-cpta)2(phen)3(H2O)2]n (6), {[Zn3(μ3-cpta)2(phen)3]·3H2O} (7), [Cd2(μ4-cpta)(μ-Cl)(phen)2]n (8), [Cd3(μ5-cpta)2(phen)2(H2O)2]n (9), [Cd3(μ4-cpta)2(phen)3(H2O)2]n (10), [Cd3(μ5-cpta)2(H2biim)2]n (11), [Zn2(μ6-cpta)(μ-Hbiim)]n (12), and [Ni3(μ3-cpta)2(phen)3(py)3(H2O)3]n (13). These compounds were assembled in the presence of an optional N-donor ancillary ligand, which was selected from 1,10-phenanthroline (phen), pyridine (py), 2,2′-bipyridine (2,2′-bipy), or 2,2′-biimidazole (H2biim). The obtained compounds 1–13 were fully characterized, including by IR spectroscopy, elemental analysis, thermogravimetric analysis (TGA), powder (PXRD) and single-crystal X-ray diffraction. The structures of 1–13 vary from a discrete 0D dimer (1) to the 1D (2, 3, 7, and 13) and 2D (5, 6, and 8–11) coordination polymers, as well as to the 3D metal–organic frameworks (MOFs 4 and 12). Such a wide structural diversity of 1–13 is guided by the following factors: a type of metal(II) node and counter anion, a deprotonation degree of the principal H3cpta block, and/or a type of an auxiliary ligand. Topological classification of H-bonded (in 1) and metal–organic (in 2–13) underlying networks was performed, disclosing the following topological types: sql (in 1), 2C1 (in 2 and 7), 3,4,5L45 (in 5, 9, and 11), 3,4L128 (in 6 and 10), 3,3,4L29 (in 8), and SP 1-periodic net (in 13), as well as some topologically unique nets (in 3, 4, and 12). Besides, magnetic properties of 2, 5, 6, and 13 were studied and modeled, revealing antiferromagnetic interactions between adjacent metal(II) centers. In addition, luminescence properties were investigated for 1, 3, 4, and 7–12; MOF 4 can be used as a sensitive material for the detection of Fe3+ ions in aqueous solution through the luminescence quenching effect.

A three-component aqueous reaction system comprising copper(II) acetate (metal node), poly(carboxylic acid) with a phenylpyridine or biphenyl core (main building block), and 1,10-phenanthroline (crystallization mediator) was investigated under hydrothermal conditions. As a result, four new coordination compounds were self-assembled, namely, {[Cu(μ3-cpna)(phen)]·H2O}n (1), {[Cu(μ-Hbtc)(phen)]·H2O}n (2), {[Cu(μ3-Hcpic)(phen)]·2H2O}n (3), and [Cu6(μ-Hcptc)6(phen)6]·6H2O (4), where H2cpna = 5-(2′-carboxylphenyl)nicotinic acid, H3btc = biphenyl-2,4,4′-tricarboxylic acid, H3cpic = 4-(5-carboxypyridin-2-yl)isophthalic acid, H3cptc = 2-(4-carboxypyridin-3-yl)terephthalic acid, and phen = 1,10-phenanthroline. Crystal structures of compounds 1–3 reveal that they are 1D coordination polymers with a ladder, linear, or double-chain structure, while product 4 is a 0D hexanuclear complex. All of the structures are extended further [1D → 2D (1 and 2), 1D → 3D (3), and 0D → 3D (4)] into hydrogen-bonded networks. The type ...

Four new crystalline solids, namely [Co-2(mu(2)-5-Clnic)2(mu(3)-5-Clnic)2(mu(2)-H2O)(n), (1), [Co(5-Clnic)(2)(H2O)(4)]center dot 2 (5-ClnicH) (2), [Pb(mu(2)-5-Clnic)(2)(phen)](n) (3), and [Cd(5-Clnic)(2)(phen)(2)]center dot 3H(2)O (4) were generated by hydrothermal self-assembly methods from the corresponding metal(II) chlorides, 5-chloronicotinic acid (5-ClnicH) as a principal building block, and 1,10-phenanthroline (phen) as an ancillary ligand (optional). All the products 1-4 were characterized by IR spectroscopy, elemental analysis, thermogravimetric (TGA), powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. Their structures range from an intricate 3D metal-organic network 1 with the 3,617 topology to a ladder-like 1D coordination polymer 3 with the 2C1 topology, whereas compounds 2 and 4 are the discrete OD monomers. The structures of 2 and 4 are further extended (0D -> 2D or 0D -> 3D) by hydrogen bonds, generating supramolecular networks with the 3,8L18 and ins topologies, respectively. Synthetic aspects, structural features, thermal stability, magnetic (for 1) and luminescent (for 3 and 4) properties were also investigated and discussed. (C) 2016 Elsevier Inc. All rights reserved.

4-(5-Carboxypyridin-2-yl)isophthalic acid (H3L) was applied as a flexible, multifunctional N,O-building block for the hydrothermal self-assembly synthesis of two novel coordination compounds, namely 2D [Zn(μ3-HL)(H2O)]n·nH2O (1) and 3D [Pb2(μ5-HL)(μ6-HL)]n (2) coordination polymers (CPs). These compounds were obtained in aqueous medium from a mixture containing zinc(II) or lead(II) nitrate, H3L, and sodium hydroxide. The products were isolated as stable crystalline solids and were characterized by IR spectroscopy, elemental, thermogravimetric (TGA), powder (PXRD) and single-crystal X-ray diffraction analyses. Compound 1 possesses a 2D metal-organic layer with the fes topology, which is further extended into a 3D supramolecular framework via hydrogen bonds. In contrast, compound 2 features a very complex network structure, which was topologically classified as a binodal 5,6-connected net with the unique topology defined by the point symbol of (47.63)(49.66). Compounds 1 and 2 disclose an intense blue or green luminescent emission at room temperature.

5-(6-Carboxypyridin-3-yl)isophthalic acid (H3L) was utilized as an almost unexplored multifunctional ligand to construct, under hydrothermal conditions, ten new coordination compounds, namely, [Cd(μ2-H2L)2]n (1), [Ni(HL)(H2biim)2] (2), [Mn(μ2-HL) (phen)(H2O)]2·2H2O (3), {[Mn3(μ4-L)2(H2O)6]·3H2O}n (4), {[Co3(μ5-L)2(H2O)6]·2H2O}n (5), {[Ni3(μ4-L)2(H2O)6]·2H2O}n (6), {[Zn3(μ5-L)2(H2O)4]·2H2O}n (7), {[Mn3(μ5-L)2(H2O)6]·4H2O}n (8), {[Co3(μ4-L)2(μ2-4,4′-bipy)(H2O)6]·2H2O}n (9), and {[Ni3(μ5-L)2(H2O)6]·2H2O}n (10), also using an optional auxiliary ligand selected from 2,2′-biimidazole (H2biim), 1,10-phenanthroline (phen), or 4,4′-bipyridine (4,4′-bipy). The obtained compounds 1–10 were analyzed by IR spectroscopy, thermogravimetric and elemental analysis, and single-crystal and powder X-ray diffraction. The structures of the products vary from 3D MOFs (metal–organic frameworks 5 and 7–10) to 2D CPs (coordination polymers 1, 4, and 6) as well as to a discrete 0D monomer 2 and a dimer 3. The latter two are extende...

A new series of eight lanthanide coordination compounds, namely [Ln(5-Fnic)3(H2O)3]2·2H2O (Ln = La (1), Pr (2), Nd (3), Eu (4), Gd (5), and Tb (6)), [Tm(5-Fnic)2(H2O)4]2[5-Fnic]2·2H2O (7), and [Eu(5-Fnic)2(phen)2(NO3)(H2O)]·2H2O (8) were generated by a hydrothermal self-assembly method in H2O from the corresponding lanthanide metal(III) nitrates, with 5-fluoronicotinic acid (5-FnicH) as the main building block, and an optional (for 8) 1,10-phenanthroline (phen) as an ancillary ligand. All the products (1–8) were fully characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single-crystal X-ray diffraction analyses. Compounds 1–6 are isostructural and reveal neutral dilanthanide(III) molecular units, 7 is ionic and has a cationic Tm2 core, whereas 8 displays a mononuclear structure. Distinct crystal packing patterns driven by strong intermolecular hydrogen bonds were observed in 1–6, 7, and 8, resulting in the 0D → 3D (1–7) or 0D → 1D (8) extension of the structures into H-bonded networks; their topological analysis and classification were performed. Products 1 and 3–8 constitute the first La, Nd, Eu, Gd, Tb, and Tm coordination compounds derived from 5-fluoronicotinic acid. The magnetic properties of compounds 2, 3, 5, and 7 were investigated. Besides, products 4, 6, and 8 exhibit a reversible temperature-induced dehydration/hydration behavior, which also influences their solid state luminescence properties that were studied in detail. The intensity of the emission bands of the dehydrated samples greatly increases after thermal removal of water molecules and then returns back to the original level upon exposure to water. This reversible behavior is more pronounced in 8 given the additional presence of phenanthroline moieties.

Biphenyl-2,4,4′-tricarboxylic acid (H3btc) was applied as a principal but still little explored building block for the synthesis of nine new coordination compounds, namely, [Zn(H2btc)(phen)2][H2btc]·H2O (1), [M(H2btc)2(H2biim)2] {M = Co (2) and Cd (3)}, [Ni(Hbtc)(phen)2(H2O)]·2H2O (4), [Cd2(μ4-btc)(μ2-Cl)(phen)2]n (5), [Ni3(μ4-btc)2(μ2-H2O)2(py)4(H2O)2]n (6), {[Co3(μ4-btc)2(μ2-H2O)2(py)4(H2O)2]·(py)2}n (7), {[Co3.5(μ6-btc)2(μ3-OH)(py)2(H2O)3]·H2O}n (8), and {[Pb3(μ6-btc)2(H2O)]·H2O}n (9). These products were easily generated by a hydrothermal self-assembly method from the corresponding metal(II) chlorides, H3btc, and various N-donor ancillary ligands, selected from 1,10-phenanthroline (phen), 2,2′-biimidazole (H2biim), or pyridine (py). Compounds 1–9 were characterized by IR spectroscopy, elemental, thermogravimetric, powder and single-crystal X-ray diffraction analyses. Their structures range from the intricate 3D metal–organic frameworks (MOFs) 6–9 to the 2D coordination polymer 5 and the discrete 0D monomers 1–4. Such a structural diversity is guided by the type of metal(II) node, level of the deprotonation of biphenyl-2,4,4′-tricarboxylic acid, and kind of ancillary ligand. The structures of 1–4 are further extended [0D → 2D (1) and 0D → 3D (2–4)] into various H-bonded networks. Both the supramolecular (in 1–4) and coordination (in 5–9) underlying networks were classified from the topological viewpoint, disclosing the distinct 4,5L64 (in 1), pcu (in 2 and 3), sxb (in 4), hcb (in 5), and wei (in 6 and 7) topological nets, whereas topologically unique frameworks were identified in MOFs 8 and 9. The magnetic (for 6–8) and luminescence (for 1, 3, 5, and 9) properties were also studied and discussed.

Two compounds, namely a 2D coordination polymer {[Ni(µ 3-bpdc)(H2O)]·H2O} n (1) and a 3D metal–organic framework (MOF) [Mn(µ 4-bpdc)(phen)] n (2), were generated by a hydrothermal self-assembly from the corresponding metal(II) chlorides, 2,2′-bipyridine-5,5′-dicarboxylic acid (H2bpdc) as a main building block, and an optional ancillary 1,10-phenanthroline (phen) ligand. The obtained products were characterized by IR spectroscopy, elemental, thermogravimetric, powder and single-crystal X-ray diffraction analyses. Compound 1 possesses a 2D double-layered network with the plane SP KIa topology defined by the point symbol of (82.10), which is further extended into a 3D supramolecular architecture via hydrogen bonds. MOF 2 features a 3D net with the pts topology and point symbol of (42.84). The magnetic properties for both compounds were also investigated, indicating antiferromagnetic interactions between the adjacent metal ions. Two 2D and 3D metal–organic networks driven by a multifunctional building block were self-assembled and fully characterized; their structural, topological, and magnetic features were investigated.

Two multifunctional, ether-bridged tricarboxylic acids, 2-(4-carboxylphenoxy)terephthalic acid (H3cpta) and 2-(3,5-dicarboxylatobenzyloxy)benzoic acid (H3dbba), were used as unexplored and highly versatile building blocks for the hydrothermal generation of a novel series of cadmium(ii) metal-organic architectures. These were formulated as [Cd(μ-Hcpta)(phen)(py)]n (1), {[Cd3(μ5-cpta)2(phen)3]·8H2O}n (2), {[Cd3(μ5-cpta)2(2,2'-bipy)3]·6H2O}n (3), {[Cd(μ3-cpta)(Hbpa)]·2H2O}n (4), {[Cd6(μ4-cpta)2(μ6-cpta)2(H2biim)2(H2O)6]·5H2O}n (5), [Cd3(μ4-cpta)2(μ-prz)(H2O)4]n (6), {[Cd3(μ4-dbba)2(phen)3]·H2O}n (7), and {[Cd3(μ3-dbba)2(2,2'-bipy)3(H2O)3]·2H2O}n (8) on the basis of single-crystal X-ray diffraction, elemental analysis, FTIR, PXRD, and TGA data. Products 1-8 were assembled in the presence of N-donor crystallization mediators selected from pyridine (py), 1,10-phenanthroline (phen), 2,2'-bipyridine (2,2'-bipy), bis(4-pyridyl)amine (bpa), 2,2'-biimidazole (H2biim), or piperazine (prz). The nature of the crystallization mediator and/or the type of principal tricarboxylate building block have a significant effect on the structural diversity, dimensionality, and topology of the resulting cadmium-organic architectures. These span from 1D (1, 8) and 2D (7) coordination polymers to 3D metal-organic frameworks (2-6) with intricate topologies (3,4,5T64 in 2 and 3, utp (103)-d in 4, 3,4,4T9 in 6) that also include unprecedented types in 5 and 7. Besides, MOF 6 features a 3D + 3D two-fold interpenetrated framework. Luminescent and photocatalytic properties of selected materials were investigated, showing that coordination polymer 7 is a promising photocatalyst for the UV-light-driven degradation of methylene blue as a model organic dye pollutant. Moreover, products 7 and 8 are the first examples of structurally characterized coordination compounds derived from H3dbba.

This study reports the hydrothermal synthesis of a novel series of twelve coordination compounds, namely, {[Cd(μ-Hnbtc)(H2O)4]·H2O}n (1), [Zn2(μ-Hnbtc)2(phen)2]·2H2O (2), [Zn(Hnbtc)(phen)2(H2O)]·4.5H2O (3), [Ni(Hnbtc)(phen)2(H2O)]·6H2O (4), [Zn2(μ-Hnbtc)2(2,2′-bipy)2]·2H2O (5), [Cd3(μ5-nbtc)(μ6-nbtc)(2,2′-bipy)2(H2O)]n (6), {[Zn3(μ3-nbtc)2(phen)3(H2O)2]·4H2O} (7), [Co(H2O)6][Co2(nbtc)2(μ-4,4′-bipy)(4,4′-bipy)2(H2O)6]·8H2O (8), {[Ni3(μ4-nbtc)2(μ-4,4′-bipy)2.5(μ-H2O)(H2O)3]·4H2O}n (9), {[Cd2(μ4-nbtc)(μ-OH)(2,2′-bipy)2]·H2O}n (10), [Cd2(μ4-nbtc)(μ-OH)(phen)2(H2O)]n (11), and {[Zn2(μ5-nbtc)(μ3-OH)(μ-4,4′-bipy)]·4,4′-bipy·H2O}n (12), which are derived from 3′-nitro-biphenyl-2,4,4′-tricarboxylic acid (H3nbtc) as a virtually unexplored building block. These compounds were generated in aqueous medium from the corresponding metal(II) chlorides as a metal source, H3nbtc as a principal building block, NaOH as a base, and simple N,N-donor aromatic ligands as crystallization mediators (i.e., 1,10-phenanthroline, phen; 2,2′-bipyridine, 2,2′-bipy; or 4,4′-bipyridine, 4,4′-bipy). All products 1–12 were completely characterized in the solid state by IR spectroscopy, elemental and thermogravimetric (TGA) analyses, powder (PXRD) and single-crystal X-ray diffraction. Structures of 1–12 range from discrete 0D dimers (2 and 5) or monomers (3, 4, and 8) to 1D coordination polymers (CPs, 1, 6, 7, 10, and 11) and 3D metal–organic frameworks (MOFs, 9 and 12). A broad structural diversity of 1–12 is guided by the type of the metal(II) node, the molar ratio between H3nbtc and sodium hydroxide, and the kind of crystallization mediator. Topological analysis and classification of metal–organic underlying nets was made, disclosing the following topological types: 2C1 (in 1 and 7), 1M2-1 (in 2 and 5), SP1-periodic net (in 10 and 11), tfz-d (in 12), and some topologically unique nets (in 6 and 9). Luminescence behavior of 1–3, 5–7, and 10–12 was studied in the solid state. Magnetic properties of a Ni(II) MOF 9 were also investigated and modeled. All obtained products 1–12 represent the first structurally characterized examples of coordination compounds derived from H3nbtc, thus opening up its application in coordination chemistry as a novel tricarboxylate building block.

Selected recent examples of coordination polymers (CPs) or metal-organic frameworks (MOFs) constructed from different multifunctional carboxylic acids with phenyl-pyridine or biphenyl cores have been discussed. Despite being still little explored in crystal engineering research, such types of semi-rigid, thermally stable, multifunctional and versatile carboxylic acid building blocks have become very promising toward the hydrothermal synthesis of metal-organic architectures possessing distinct structural features, topologies, and functional properties. Thus, the main aim of this mini-review has been to motivate further research toward the synthesis and application of coordination polymers assembled from polycarboxylic acids with phenyl-pyridine or biphenyl cores. The importance of different reaction parameters and hydrothermal conditions on the generation and structural types of CPs or MOFs has also been highlighted. The influence of the type of main di- or tricarboxylate ligand, nature of metal node, stoichiometry and molar ratio of reagents, temperature, and presence of auxiliary ligands or templates has been showcased. Selected examples of highly porous or luminescent CPs, compounds with unusual magnetic properties, and frameworks for selective sensing applications have been described.

Two new coordination compounds, namely a 3D metal-organic framework (MOF) {[Cd-2(L)(2)(phen)(2)]center dot H2O}(n) (1) and a discrete 0D dimer [Mn(L)(0.5)(HL)(phen)(2)](2)center dot 2H(2)O (2), were generated by a hydrothermal method from the metal(II) chlorides, 4,4'-(pyridine-2,5-diyl)dibenzoic acid (H2L) as a main building block, and an ancillary 1,10-phenanthroline (phen) ligand. The products 1 and 2 were characterized by IR spectroscopy, elemental, thermogravimetric, and single-crystal X-ray diffraction analyses. Compound 1 possesses an intricate 3D metal-organic framework based on tetracadmium(II) double-helicate units which, after simplification, resulted in a 4-fold interpenetrated underlying net with the dia topology. Compound 2 features a dimeric molecular structure, which is extended (0D -> 1D) by hydrogen bonds into a 1D double chain network. It was topologically classified as a simple 3-connected ladder with the SP 1-periodic net (4,4)(0,2) topology. The luminescent (for 1) and magnetic (for 2) properties were also investigated and discussed. (C) 2015 Elsevier B.V. All rights reserved.

A series of novel mixed-ligand coordination polymers, namely, {[Cd2(μ4-L)(μ3-OH)(phen)2]·2H2O}n (1), {[Mn3(μ5-L)2(phen)2(H2O)]·H2O}n (2), [Cd2(μ3-L)(H2biim)2(μ2-Hbiim)]n (3), {[Pb2(μ4-L)(μ4-bpdc)0.5(phen)2]·H2O}n (4), [Cd2(μ5-L)(μ2-bpdc)0.5(phen)2]n (5), and [Zn2(μ4-L)(μ2-bpdc)0.5(py)2]n (6), was hydrothermally synthesized using 4-(5-carboxypyridin-2-yl)isophthalic acid (H3L) as a new and virtually unexplored multifunctional pyridine-tricarboxylate building block, along with various auxiliary ligands {phen = 1,10-phenanthroline, H2biim = 2,2′-biimidazole, H2bpdc = 4,4′-biphenyldicarboxylic acid, and py = pyridine}. All the products 1–6 were characterized by IR spectroscopy, elemental, thermogravimetric, and single-crystal X-ray diffraction analyses. Compounds 1, 3, and 5 reveal 2D metal–organic layers with the kgd, fes, and 3,4,5L5 topology, respectively, whereas the metal–organic frameworks (MOFs) 2, 4, and 6 disclose 3D underlying nets with the unique (2, 4) or ins (6) topology. The results indicate that the nature of the metal(II) ion and type of auxiliary ligand play a significant role in determining the dimensionality, topology and other structural features of the obtained products. Luminescent (for 1 and 3–6) and magnetic (for 2) properties were studied and discussed.

Five new coordination compounds, namely [Ni(5-Fnic)2(μ2-H2O)0.5]n (1), [Co(5-Fnic)2(H2biim)]n (2), {[Cd(5-Fnic)2(phen)]·2H2O}n (3), [Cd(5-Fnic)2(H2biim)2] (4), and [Co(5-Fnic)2(H2O)4] (5), were generated by hydrothermal methods from the metal(II) nitrates, 5-fluoronicotinic acid (5-FnicH), and an optional ancillary 1,10-phenanthroline (phen) or 2,2′-biimidazole (H2biim) ligand. All the products 1–5 were characterized by IR spectroscopy, elemental, thermogravimetric, and single-crystal X-ray diffraction analyses. Their structures range from the intricate 3D metal–organic framework (MOF) 1 to the 1D coordination polymers 2 and 3, and the discrete 0D monomers 4 and 5. The structures of 2–5 are further extended [1D → 2D (2), 1D → 1D (3), 0D → 1D (4), and 0D → 3D (5)] into various H-bonded networks. The topological analysis of the underlying coordination (in 1) and H-bonded (in 2–5) nets revealed a very rare 3,6T10 MOF topology in 1, a parallel 2D + 2D interpenetration of the sql nets in 2, a topologically unique double chain in 3, a simple 2C1 topology in 4, and a pcu (alpha-Po primitive cubic) topology in 5. The magnetic (for 1 and 2) and luminescent (for 3 and 4) properties were also investigated and discussed.

A novel flexible multifunctional building block (H3L) bearing picolinate and terephthalate functionalities was designed and applied for the hydrothermal self-assembly generation of a series of coordination compounds [Co(H2L)2(H2O)2] (1), [M(HL)(H2O)]n {M = Cd (2) and Mn (3)}, {[Mn1.5(L)(phen)(H2O)2]·H2O}n (4), [Zn3(L)2(H2O)6]n (5), and {[Zn3(L)2(py) (H2O)4]·4H2O}n (6) {wherein H3L = 2-(4-carboxypyridin-3-yl)-terephthalic acid, phen = 1,10-phenanthroline, py = pyridine}. All the obtained products 1–6 were fully characterized by IR spectroscopy, elemental, thermogravimetric, powder and single-crystal X-ray diffraction analyses. By adjusting the molar ratio of NaOH and H3L ligand, the latter becomes partially deprotonated to form the H2L− blocks in 1 and HL2− moieties in 2 and 3, or completely deprotonated to create the L3− units in 4–6. The structures of the obtained compounds range from a discrete 0D monomer 1 and 1D coordination polymers 4 and 5 to 2D coordination polymers 2 and 3, and an intricate 3D metal–organic framework 6; their detailed topological classification was also performed. The structures of 1–5 are further extended [0D → 3D (1), 1D → 3D (4, 5), and 2D → 3D (2, 3)] into supramolecular networks by means of multiple hydrogen bonds. The results reveal that the nature of metal(II) ion, molar ratio between NaOH and H3L ligand, and the presence (optional) of auxiliary ligand play a significant role in determining dimensionality, topology and other structural features of the obtained products. Magnetic susceptibility measurements indicate that compounds 3 and 4 have dominating antiferromagnetic couplings between metal centers. Furthermore, luminescent properties of 2, 5, and 6 were also investigated.

New iron(II) three-dimensional coordination polymer (3D CP), [Fe(&micro, 3-Hcpna)2]n (1), was assembled under hydrothermal conditions from 5-(4&rsquo, carboxyphenoxy)nicotinic acid (H2cpna) as a trifunctional organic N,O-building block. This stable microcrystalline CP was characterized by standard methods for coordination compounds in the solid state (infrared spectroscopy, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffraction). Structure and topology of 1 were examined and permitted an identification of a 3,6-connected framework of the rtl topological type. In addition, compound 1 acts as effective catalyst precursor for oxidative functionalization of alkanes (propane and cyclic C5&minus, C8 alkanes) under homogeneous catalysis conditions, namely for the oxidation of saturated hydrocarbons with H2O2/H+ system to produce ketones and alcohols, and for alkane carboxylation with CO/H2O/S2O82&minus, system to obtain carboxylic acids. The influence of an acid promoter and substrate scope (propane and cyclic C5&minus, C8 alkanes) were investigated.

A ligand 5-(2′-carboxylphenyl) nicotic acid (H2cpna) has been successfully applied to construct a series of coordination complexes {[Cd(Hcpna)2(H2O)2]·3H2O}n (1), [Cd(cpna)(H2O)]n (2), [M(cpna)(2,2′-bipy)(H2O)]n (M = Cd (3), Co (4), and Mn (5)), [Co(cpna)(phen)(H2O)]n (6), [Mn(cpna)(phen)(H2O)]n (7), {[Nd(Hcpna)(cpna)(H2O)2]·3H2O}n (8), and {[Ln(Hcpna)(cpna)(phen)]·2H2O}n (Ln = Pr (9), Nd (10), Eu (11), and Gd (12), 2,2′-bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline) under hydrothermal conditions. By adjusting the reaction pH, H2cpna ligand is partially deprotonated to form Hcpna– in 1 and completely deprotonated to create cpna2– in 2–7, and both forms are observed in 8–12. Complexes 1–5 and 8 possess two-dimensional (2D) layered structures, which are further extended into 3D metal–organic supramolecular frameworks by C–H···O hydrogen bond and/or π–π stacking interactions. Complexes 6, 7, and 9–12 exhibit one-dimensional (1D) chain structures, which further build three-dimensional (3D) supramolecular...

Two lanthanide(III) coordination polymers, namely [Ce(pzdc)1.5(H2O)] n (1), [Er(pzdc)(μ2-OH)(H2O)] n ·nH2O (2) (H2pzdc = pyrazine-2,5-dicarboxylic acid), have been hydrothermally synthesized and characterized by single crystal X-ray diffraction and magnetic measurements. Polymer 1 crystallizes in triclinic space group P-1, with a = 6.2875(6), b = 6.7396(6), c = 13.3858(14) A, α = 82.858(4), β = 83.118(4), γ = 63.452(4)°, V = 502.16(8) A3, and Z = 2. Polymer 2 crystallizes in monoclinic space group P2(1)/c, with a = 11.706(4), b = 6.151(2), c = 14.063(5) A, β = 92.255(3), V = 502.16(8) A3, and Z = 4. Single-crystal X-ray diffraction studies show that compound 1 possess a 3D framework structure consisted of double chains. Compound 2 features a 3D open framework structure with a dinuclear Er(III) secondary building unit. Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Ce(III) ions. Two lanthanide(III) coordination polymers, namely [Ce(pzdc)1.5(H2O)]n (1), [Er(pzdc)(μ2-OH)(H2O)]n·nH2O (2), have been hydrothermally synthesized and characterized. Compound 1 possess a 3D framework structure consisted of double chains. Compound 2 features a 3D open framework structure with a dinuclear Er(III) secondary building unit. Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Ce(III) ions.

A new heterocyclic carboxylate ligand, 5-(4′-pyridyl)-3-methyl-benzoic acid (Hpmba), was synthesized to construct a Mn(II) coordination polymer, namely [Mn(pmba)2] n (1). Complex 1 crystallizes in monoclinic space group C2/c, with a = 17.44(2), b = 17.040(12), c = 8.680(15) A, β = 111.258(13), V = 2404(5) A3, and Z = 4. Single-crystal X-ray diffraction studies show that complex 1 has a 3D metal-organic supramolecular framework consisting of double helical chains. Magnetic studies for complex 1 show antiferromagnetic coupling between the nearest Mn(II) ions, with g = 2.11 and J = −10.1 cm−1. A new Mn(II) coordination polymer [Mn(pmba)2] n (1) based on Hpmba has been synthesized and structurally characterized. It has a 3D metal-organic supramolecular framework consisting of double-helix chains. Magnetic analysis indicates weak antiferromagnetic coupling between Mn(II) ions.

Four coordination polymers, [Zn(pda)(bpy)(H{sub 2}O)]{sub n}.nH{sub 2}O (1), [Cd(pda)(prz)(H{sub 2}O)]{sub n} (2), [Co{sub 3}({mu}{sub 3}-OH){sub 2}(pda){sub 2}(pyz)]{sub n}.2nH{sub 2}O (3) and [Pr{sub 2}(pda){sub 3}(H{sub 2}O){sub 2}]{sub n} (4) (H{sub 2}pda=1,3-phenylendiacetic acid, bpy=4,4'-bipyridine, prz=piperazine and pyz=pyrazine) have been hydrothermally synthesized and characterized. Complex 1 is a 1D wheel-like chain structure, which is further extended into a 3D metal-organic supramolecular framework by H-bonds and {pi}-{pi} stacking interactions. Complex 2 is a 1D ladder-like chain structure, which is also further extended into a 3D metal-organic supramolecular framework by H-bonds. Complex 3 possess a 2D sheet structure with infrequent two pairs of double-helix chains. Complex 4 features a 3D structure. Both 1 and 2 display strong blue fluorescent emission at room temperature. Magnetic susceptibility measurements of complexes 3 and 4 exhibit antiferromagnetic interactions between the nearest metal ions, with C=9.99 and 3.43 cm{sup 3} mol{sup -1} K, and {theta}=-23.9 and -46.3 K, respectively. -- Graphical abstract: Four new coordination polymers with 1,3-phenylenediacetate ligands have been hydrothermally synthesized and characterized. Complexes 1 and 2 display strong blue fluorescent emission at room temperature. Magnetic susceptibility measurements of 3 and 4 exhibit antiferromagnetic interactions between the nearest metal centers. Display Omitted Research highlights: > Coordinative property ofmore » H{sub 2}pda ligand was shown when bonded by different block metals. > Careful selection of co-ligand and metals resulted in dramatic framework evolution. > (c) The compounds constructed with Zn{sup 2+} and Cd{sup 2+} exhibit strong blue fluorescent emission. > The magneto-structural correlation of the complexes constructed with Co{sup 2+} and Pr{sup 3+} was elucidated.« less

Two coordination polymers, namely [M(cpna)(phen)(H2O)] n (M = Ni, 1; Cd, 2, H2cpna = 5-(2′-carboxylphenyl) nicotic acid, phen = 1,10-phenanthroline), have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, magnetic and luminescence measurements. Single-crystal X-ray diffraction studies show that the two complexes are isostructural polymers. They have 1D step-like chain structures, which are further extended into 3D metal–organic supramolecular frameworks by π–π stacking interactions. Magnetic studies for complex 1 show antiferromagnetic coupling between the adjacent Ni(II) centers, with g = 2.10 and J = −4.30 cm−1. Complex 2 displays strong green fluorescent emission at room temperature.

Two Mn(II) coordination polymers, namely [Mn(bpda)] n (1) and [Mn(bpda)(bpy)0.5] n (2) (H2bpda = 1,1′-biphenyl-3,3′-dicarboxylic acid and bpy = 4,4′-bipyridine), have been synthesized from H2bpdc, bpy, and MnSO4·2H2O under hydrothermal conditions. The complexes were characterized by physicochemical and spectroscopic methods, as well as by X-ray crystallography. Compound 1 possesses a 3D structure consisting of carboxylate-bridged edge-sharing Mn–O–Mn double chains. Compound 2 features a 3D open structure with a dinuclear Mn(II) secondary building unit. Magnetic susceptibility measurements of compounds 1 and 2 exhibit antiferromagnetic interactions between the nearest Mn(II), with J = –11.3 cm−1 and g = 2.12 for 1, and J = –13.5 cm−1 and g = 2.12 for 2.

Three Co(II) and Ni(II) complexes, namely [Co(bpdc)(H2O)2] (1), [Ni(bpdc)(H2O)2] (2), and [Co2(bpdc)2(prz)0.5(H2O)3]·0.5H2O (3) (H2bpdc = 2,2′-bipyridine-6,6′-dicarboxylic acid and prz = piperazine), have been synthesized from H2bpdc and the corresponding metal salts under hydrothermal conditions. The complexes were characterized by physico-chemical and spectroscopic methods, as well as by X-ray crystallography. Compounds 1 and 2 both consist of neutral mononuclear molecules, of [Co(bpdc)(H2O)2] and [Ni(bpdc)(H2O)2], respectively. Compound 3 consists of a mononuclear molecule of [Co(bpdc)(H2O)2] and a binuclear molecule of [Co2(bpdc)2prz (H2O)2]. The discrete neutral complexes 1–3 further extend their structures into three-dimensional supramolecular architectures by intermolecular O–H⋯O and C–H⋯O hydrogen bonds as well as π–π stacking interactions. Magnetic susceptibility measurements show that complex 3 exhibits weak ferromagnetic interactions between the two Co(II) ions bridged by the prz ligand, with C = 5.41 cm3 mol−1 K and θ = +27.6 K, respectively.

Two new three-dimensional (3D) coordination compounds, namely a lead(II) coordination polymer (CP) {[Pb3(&micro, 5-cpta)(&micro, 6-cpta)(phen)2]&middot, 2H2O}n (1) and a zinc(II) metal-organic framework (MOF) {[Zn2(&micro, 4-cpta)(&micro, OH)(&micro, 4,4&prime, bipy)]&middot, 6H2O}n (2), were hydrothermally assembled from 2-(5-carboxypyridin-2-yl)terephthalic acid (H3cpta) as an unexplored principal building block and aromatic N,N-donors as crystallization mediators. Both products were isolated as air-stable microcrystalline solids and were fully characterized by IR spectroscopy, elemental and thermogravimetric analysis, and powder and single-crystal X-ray diffraction. Structural and topological features of CP 1 and MOF 2 were analyzed in detail, allowing to identify a topologically unique 4,5,5,6-connected net in 1 or a very rare 4,4-connected net with the isx topology in 2. Thermal stability and solid-state luminescent behavior of 1 and 2 were also investigated. Apart from revealing a notable topological novelty, both compounds also represent the first structurally characterized Pb(II) and Zn(II) derivatives assembled from H3cpta, thus opening up the application of this unexplored pyridine-tricarboxylate block in the design of new metal-organic architectures.

A coordination polymer [Co(dpa)pyz0.5] n (1) with double-helix chains has been constructed hydrothermally using H2dpa (H2dpa = diphenic acid), pyz (pyz = pyrazine) and Co(NO3)2· 6H2O. Its structure and magnetic properties were investigated. The compound crystallizes in the triclinic space group P -1. Each Co atom is five-coordinated and takes a distorted tetragonal pyramid geometry. Two carboxylates of the H2dpa ligands bridge four Co(II) ions to form infinite right-handed or left-handed helical ─C─O─Co─ chains. The two types of helical chains are interconnected to each other through the Co(II) centers to produce double-helix chains. The chains form a 2D sheet through the coordination interaction of pyz molecules between adjacent chains. Magnetic studies for complex 1 show stronger antiferromagnetic coupling between the Co(II) ions.