Hydrothermal Assembly, Structural Multiplicity, and Catalytic Knoevenagel Condensation Reaction of a Series of Coordination Polymers Based on a Pyridine-Tricarboxylic Acid

A pyridine-tricarboxylic acid, 5-(3',5'-dicarboxylphenyl)nicotinic acid (H3dpna), was employed as a adjustable block to assemble a series of coordination polymers under hydrothermal conditions. The seven new coordination polymers were formulated as [Co(μ3-Hdpna)(μ-dpey)]n·nH2O (1), [Zn4.5(μ6-dpna)3(phen)3]n (2), [Co1.5(μ6-dpna)(2,2'-bipy)]n (3), [Zn1.5(μ6-dpna)(2,2'-bipy)]n (4), [Co3(μ3-dpna)2(4,4'-bipy)2(H2O)8]n·2nH2O (5),[Co(bpb)2(H2O)4]n[Co2(μ3-dpna)2(H2O)4]n·3nH2O (6), and [Mn1.5(μ6-dpna)(μ-dpea)]n (7), wherein 1,2-di(4-pyridyl)ethylene (dpey), 1,10-phenanthroline (phen), 2,2'-bipyridine(2,2'-bipy),4,4'-bipyridine(4,4'-bipy),1,4-bis(pyrid-4-yl)benzene (bpb), and 1,2-di(4-pyridyl)ethane (dpea) were employed as auxiliary ligands. The structural variation of polymers 1-7 spans the range from a 2D sheet (1-4, 6, and 7) to a 3D metal-organic framework (MOF, 5). Polymers 1-7 were investigated as heterogeneous catalysts in the Knoevenagel condensation reaction, leading to high condensation product yields (up to 100%) under optimized conditions. Various reaction conditions, substrate scope, and catalyst recycling were also researched. This work broadens the application of H3dpna as a versatile tricarboxylate block for the fabrication of functional coordination polymers.

Coordination Polymers from an Amino-Functionalized Terphenyl-Tetracarboxylate Linker: Structural Multiplicity and Catalytic Properties

An amino-functionalized terphenyl-tetracarboxylic acid, 2'-amino-[1,1':4',1″-terphenyl]-3,3″,5,5″-tetracarboxylic acid (H4tpta), was used as an adaptable linker to synthesize, under hydrothermal conditions, eight coordination polymers (CPs). The obtained products were formulated as [Co(μ6-H2tpta)]n (1), [Co(μ3-H2tpta)(2,2'-bipy)]n (2), [M3(μ6-Htpta)2(2,2'-bipy)2]n (M = Mn (3), Cd (4)), [Ni2(μ4-tpta)(phen)2(H2O)4]n (5), [Zn2(μ6-tpta)(phen)2]n (6), {[Zn2(μ6-tpta)(μ-4,4'-bipy)]·H2O}n (7), and [Zn2(μ6-tpta)(μ-H2biim)(H2O)2]n (8), wherein 2,2'-bipyridine (2,2'-bipy), 4,4'-bipyridine (4,4'-bipy), 1,10-phenanthroline (phen), or 2,2'-biimidazole (H2biim) are present as additional stabilizing ligands. The structural types of 1-8 vary from one-dimensional (1D) (2, 5) and two-dimensional (2D) (3, 4, 6) CPs to three-dimensional (3D) metal-organic frameworks (MOFs) (1, 7, and 8) with a diversity of topologies. The products 1-8 were investigated as catalysts in the Knoevenagel condensation involving aldehydes and active methylene derivatives (malononitrile, ethyl cyanoacetate, or tert-butyl cyanoacetate), leading to high condensation product yields (up to 99%) under optimized conditions. Various reaction conditions, substrate scope, and catalyst recycling were investigated. This work broadens the application of H4tpta as a versatile tetracarboxylate linker for the generation of diverse CPs/MOFs.

Syntheses, Crystal Structures, and Catalytic Properties of Three Cu(II) and Cobalt(II) Coordination Compounds Based on an Ether-Bridged Tetracarboxylic Acid

Three new products, [Cu2(μ3-dppa)(2,2'-bipy)2(H2O)]n·2nH2O (1), [Co4(μ4-dppa)2(phen)4(H2O)4]·2H2O (2), and [Co2(μ6-dppa)(μ-4,4'-bipy)(H2O)2]n·3nH2O (3) were synthesized using a hydrothermal method from Cu(II) and Co(II) metal(II) chlorides, 3-(3,4-dicarboxyphenoxy)phthalic acid (H4dppa), and different auxiliary ligands, namely 2,2'-bipyridine (2,2'-bipy),1,10-phenanthroline (phen), and 4,4'-bipyridine (4,4'-bipy). Products 1-3 were characterized by elemental analysis, FTIR, TGA, PXRD, SEM, and single-crystal X-ray crystallography. The structure of 1 features a 1D chain of the 2C1 topological type. Compound 2 shows a discrete tetrameric complex. Product 3 demonstrates a 3D metal-organic framework (MOF) with the new topology. Their structure and topology, thermal stability, and catalytic activity were studied. In particular, excellent catalytic activity was demonstrated for copper(II)-polymer 1 in the cyanosilylation reaction at 35 °C.

Six metal-organic architectures from a 5-methoxyisophthalate linker: assembly, structural variety and catalytic features

A methoxy-functionalized isophthalic acid, 5-methoxy isophthalic acid (H2mia), was used a versatile linker for assembling six new metal(ii) compounds under hydrothermal conditions. The obtained products were [Cu2(μ2-mia)2(phen)2(H2O)2]·2H2O (1), [Mn(μ3-mia)(phen)]n (2), [Co(μ2-mia)(2,2'-bipy)(H2O)]n·nH2O (3), [Co(μ3-mia)(μ2-4,4'-bipy)]n·nH2O (4), [Co(μ3-mia)(py)2]n (5), and [Cd(μ2-mia)(py)(H2O)2]n·nH2O (6), where phen(1,10-phenanthroline), 2,2'-bipy(2,2'-bipyridine), 4,4'-bipy(4,4'-bipyridine) or py(pyridine) were incorporated as auxiliary ligands. The crystal structures of 1-6 range from 0D (1) and 1D (2, 3, 5, 6) CPs to a 2D network (4) with a variety of topological types. The catalytic behavior of 1-6 was studied in the cyanosilylation reaction between trimethylsilyl cyanide and aldehydes, resulting in up to 99% yields of products under optimized conditions. Various reaction parameters as well as catalyst recycling and substrate scope were investigated. This study widens the use of H2mia as a versatile dicarboxylate linker for assembling a diversity of functional metal-organic architectures with remarkable structural features and catalytic properties.

Coordination Polymers Constructed from an Adaptable Pyridine-Dicarboxylic Acid Linker: Assembly, Diversity of Structures, and Catalysis

4,4'-(Pyridine-3,5-diyl)dibenzoic acid (H₂pdba) was explored as an adaptable linker for assembling a diversity of new manganese(II), cobalt(II/III), nickel(II), and copper(II) coordination polymers (CPs): [Mn(μ₄-pdba)(H₂O)]_n (1), {[M(μ₃-pdba)(phen)]·2H₂O}_n (M = Co (2), Ni (3)), {[Cu₂(μ₃-pdba)₂(bipy)]·2H₂O}_n (4), {[Co(μ₃-pdba)(bipy)]·2H₂O}_n (5), [Co₂(μ₃-pdba)(μ-Hbiim)₂(Hbiim)]_n (6), and [M(μ₄-pdba)(py)]_n (M = Co (7), Ni (8)). The CPs were hydrothermally synthesized using metal(II) chloride precursors, H₂pdba, and different coligands functioning as crystallization mediators (phen: 1,10-phenanthroline; bipy: 2,2'-bipyridine, H₂biim: 2,2'-biimidazole; py: pyridine). Structural networks of 1-8 range from two-dimensional (2D) metal-organic layers (1-3, 5-8) to three-dimensional (3D) metal-organic framework (MOF) (4) and disclose several types of topologies: sql (in 1), hcb (in 2, 3, 5), tfk (in 4), 3,5L66 (in 6), and SP 2-periodic net (6,3)Ia (in 7, 8). Apart from the characterization by standard methods, catalytic potential of the obtained CPs was also screened in the Knoevenagel condensation of benzaldehyde with propanedinitrile to give 2-benzylidenemalononitrile (model reaction). Several reaction parameters were optimized, and the substrate scope was explored, revealing the best catalytic performance for a 3D MOF 4. This catalyst is recyclable and can lead to substituted dinitrile products in up to 99% product yields. The present study widens the use of H₂pdba as a still poorly studied linker toward designing novel functional coordination polymers.

Synthesis and structure of a zinc(II) coordination polymer assembled with 5-(3-carboxybenzyloxy)isophthalic acid and 1,2-bis(4-pyridyl)ethane

A zinc(II) coordination polymer [Zn(cyip)(bpe)] n (1), (cyipH2 = 5-(3-carboxybenzyloxy)-isophthalic acid, bpe = 1,2-bis(4-pyridyl)ethane), has been synthesized under hydrothermal conditions. Its structure was determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis and IR spectra. Complex 1 crystallizes in the monoclinic space group I2/a. In 1, the [cyip]2– ligand bridges the Zn(II) cations to form infinite chains, which are connected through O–H···O hydrogen bonds into layers in the form of 2-fold interpenetrated nets.

Crystal structure of trans-tetraaqua-bis{2-carboxy-4-((5-carboxypyridin-3-yl)oxy)benzoato-κ1 N}cobalt(II) dihydrate C28H28O20N2Co

C28H28O20N2Co, triclinic, P 1 ‾ $P‾{1}$ (no. 2), a = 7.7951(3) Å, b = 9.3511(4) Å, c = 11.3352(4) Å, β = 105.499(4)°, Z = 1, V = 762.19(6) Å3, R gt (F) = 0.0339, wR ref (F 2) = 0.0798, T = 293.0 K.

Crystal structure of catena-poly[(4-hydroxyl-5-(methoylcarbonyl)thiophene-2-carboxylato-κ1 O)-(μ2-piperazine-1,4-diylbis(pyridin-4-ylmethanone)-κ2 N:N′)silver(I)] monohydrate, C23H23AgN4O8S

C23H23AgN4O8S, monoclinic, P21/n (no. 14), a = 8.5356(4) Å, b = 27.9494(15) Å, c = 10.3796(6) Å, V = 2474.1(2) Å3, Z = 4, R gt (F) = 0.0347, wR ref(F 2) = 0.0744, T = 289 K.

Crystal structure of catena-poly[bis(µ2-3,5-bis(1-imidazolyl)pyridine-κ2 N:N′)-(µ2-3-nitrophthalato-k3 O,O′:O″)cadmium(II)] dihydrate, C30H25N11O8Cd

C30H25N11O8Cd, orthorhombic, Pnma (no. 62), a = 17.9344(3) Å, b = 18.2722(3) Å, c = 9.5619(2) Å, V = 3133.44(10) Å3, Z = 4, R gt (F) = 0.0345, wR ref (F 2) = 0.0707, T = 293.28(10) K.

Crystal structure of the 2D coordination polymer poly[diaqua-bis(μ2-3- methoxyisonicotinato-κ2 N:O)cobalt(II)] — dimethylformamide (1/1), C20H30CoN4O10

C20H30CoN4O10, monoclinic, C2/c (no. 15), a = 13.4752(4) Å, b = 12.8563(3) Å, c = 15.0144(5) Å, β = 113.429(4)°, V = 2386.66(14) Å3, Z = 4, R gt (F) = 0.0291, wR ref(F 2) = 0.0719, T = 293(2) K.

1D Zn(II) Coordination Polymers as Effective Heterogeneous Catalysts in Microwave-Assisted Single-Pot Deacetalization-Knoevenagel Tandem Reactions in Solvent-Free Conditions

The new 1D CPs [Zn(L1)(H2O)4]n.nH2O (1) and [Zn(L2)(H2O)2]n (2) [L1 = 1,1′-(ethane-1,2-diyl)bis(6-oxo-1,6-dihydropyridine-3-carboxylic acid); L2 = 1,1′-(propane-1,3-diyl)bis(6-oxo-1,6-dihydropyridine-3-carboxylic acid)] were prepared from flexible dicarboxylate pro-ligands (H2L1 and H2L2). Both CPs 1 and 2 were characterized by elemental, FTIR, and powder X-ray diffraction analysis. Their geometry and the structural features were unveiled by single-crystal X-ray diffraction analysis. The underlying topology of the CPs was illustrated by the topological analysis of the H-bonded structure of CP 1, which revealed a 3,4,6-connected trinodal net. On the other hand, topological analysis on the hydrogen-bonded network of CP 2 showed a 2,3,3,4,6,7-connected hexanodal net. The thermal stability of the CPs was investigated by thermogravimetric analysis. CPs 1 and 2 act as heterogeneous catalysts in one-pot tandem deacetalization–Knoevenagel condensation reactions under environmentally mild conditions. CPs 1 exhibits a yield of ca. 91% in a microwave-assisted solvent-free medium, whereas a slightly lower yield was obtained for CP 2 (87%) under the same experimental protocol. The recyclability of catalyst 1 was also assessed. To our knowledge, these are the first Zn(II)-based CPs to be applied as heterogeneous catalysts for the above tandem reactions under environmentally friendly conditions.

Viologen-derived material showing photochromic, visually oxygen responsive, and photomodulated luminescence behaviors

A new 2D viologen-derived Zn(ii) photochromic material exhibits photochromic, visually oxygen responsive, and photomodulated luminescent behaviors.

Two Transition Metal Coordination Polymers: Luminescent Sensing Properties and Treatment Effect on Chronic Periodontitis by Reducing IL-6 and TNF-α Content

Two novel sulfonic functionalized coordination polymers (CPs) {[Cd1.5(dimb)(5-sip)(H2O)3]·3H2O}n (1, dimb = 1,4-di(1H-imidazol-1-yl)butane) and [Co2(iptz)(Hiptz)(5-sip)(H2O)]·4H2O (2, Hiptz = 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole) were acquired via different metal(II) salts reacting with the mixed ligands containing 1-(4-(1H-imidazole-5-yl)phenyl)-1H-1,2,4-triazole, 1,4-di(1H-imidazol-1-yl)butane and sodium 5-sulfoisophthalate (NaH2sip), respectively. Furthermore, the complex 1 based on Cd(II) could be utilized as the luminescent senor for picric acid (PA) detection in water. In bio-research, compounds 1 and 2 treatment effect on chronic periodontitis was assessed and the specific mechanism was discussed. First of all, the RT-PCR was performed to measure the HmuY and fimA genes relative expression level in P.gingivalis after treated by compounds 1 and 2. Then, the TNF-α and IL-6 content in the fluid of gingival crevicular after compounds treatment was determined with ELISA detection kit.

Construction of a viologen-derived 2D material with photochromism, photoswitchable luminescence and inkless and erasable prints via sunlight irradiation

A Zn(ii) material based on thiophenedicarboxylate and viologen derivative mixed ligands is synthesized. Thanks to pyridinium unit embedded in its structure, the material exhibits a rapid photochromic response via sunlight irradiation.

Metal–organic architectures designed from a triphenyl-pentacarboxylate linker: hydrothermal assembly, structural multiplicity, and catalytic Knoevenagel condensation

Eight new metal(ii) coordination compounds driven by a triphenyl-pentacarboxylate linker were hydrothermally assembled and fully characterized. Their structural features and catalytic behavior were investigated.

Crystal structure of bis(6-aminopyridine-2-carboxylato-κ2 O,N)-copper(II), C12H10O6N4Cu

C12H10O6N4Cu, monoclinic, P21/c (no. 14), a = 3.7015(2) Å, b = 7.3920(4) Å, c = 21.3535(12) Å, β = 91.060(5)°, Z = 2, V = 584.16(6) Å3, R gt(F) = 0.0319, wR ref(F2) = 0.0769, T = 293 K.

Crystal structure of catena-poly[diaqua-(μ2-bipyridine-κ2 N:N′)-bis(3,5-dichloroisonicotinato-κO)cadmium(II)] dihydrate, C22H20CdCl4N4O8

C22H20CdCl4N4O8, monoclinic, C2/c (no. 15), a = 14.9908(5) Å, b = 11.6786(3) Å, c = 15.4664(5) Å, β = 95.448(3)°, V = 2695.50(14) Å3, Z = 4, R gt(F) = 0.0226, wR ref(F 2) = 0.0516, T = 291.5(2) K.

Crystal structure of the coordination polymer catena-poly[(1,2-di(pyridin-4-yl)ethane-κN)-(μ2-2-nitroisophthalato-κ2O:O′)zinc(II)], C20H17N3O7Zn

C20H17N3O7Zn, monoclinic, P21/n (no. 14), a = 10.4368(3) Å, b = 15.1527(5) Å, c = 12.9007(3) Å, β = 101.900(3)°, V = 1996.36(10) Å3, Z = 4, Rgt(F) = 0.0410, wRref(F2) = 0.0898, T = 293(2) K.

Crystal structure of poly[diaqua-bis(μ2-3-((1H-imidazol-1-yl)methyl)benzoato-κ2N:O)manganese(II)], C22H22MnN4O6

C22H22MnN4O6, monoclinic, P21/n, a = 11.9331(7) Å, b = 5.5962(3) Å, c = 16.0671(9) Å, β = 107.391(6)°, Z = 2, V = 1023.92(11) Å3, Rgt(F) = 0.046, wRref (F2) = 0.055, T = 287 K.