Three-dimensional Coordination Polymer Research Articles

Novel nickel(II) coordination polymer based on a semi-rigid tricarboxylate acid ligand: synthesis, structure, and fluorescence recognition of acetylacetone in aqueous media

Through a solvothermal reaction between the corresponding nickel(II) sulfate, π-electron rich tri-carboxylate ligand 4-(2′,3′-dicarboxylphenoxy) benzoic acid (H3L) and 1,2-bis (4-pyridyl) ethylene (bpe) molecule, a novel three-dimensional (3D) nickel-based coordination polymer (Ni-CP), namely [Ni3(L)2(bpe)3(H2O)4]·(H2O)6 (1) was successfully constructed. The structure was established by single-crystal X-ray diffraction, which reveals that 1 features a new 3,4,4-connected topology with the point symbol of (105·12) (4·102)2 (4·85)2. Subsequently, some studies on optical properties of compound 1 were carried out. Interestingly, the results suggest that compound 1 exhibits excellent applications as a fluorescent sensor for the recognition of Hacac via a fluorescence quenching approach. The detection limit can be as low as 10.19 µM. The possible mechanisms of the fluorescence turn-off effect were also discussed in detail. This work presents a case for monitoring Hacac concentrations in water samples.

Heterometallic coordination polymers based on CuII/LnIII cations. Solid-state and magnetic characterization

Novel heterometallic three-dimensional coordination polymers {[CuII2LnIIICl2(HIA)4(NO3)(DMF)2]∙(2DMF)∙(H2O)}n based on Ce (1), Eu (2) or Gd (3) and imidazole-4-acrylic acid (H2IA), were successfully synthesized using the sonochemical method. All attempts to obtain the compound using other synthetic methods were unsuccessful. The heterometallic polymers are isostructural, crystallizing in the chiral P3221 trigonal space group. The crystal structures correspond to an intricated 3D framework where the Cu(HIA)2 fragments generate two interpenetrated copper (II) networks, [Cu(HIA)2]n. The LnIII cations that interact with these CuII-networks through the carboxylate group belonging to the organic ligand confer a higher complexity to the 3D network. Additionally, the coordination environment around the copper (II) cations is responsible for the chirality of the structures, making these even more exciting. The three-dimensional polymers were also characterized from a magnetic point of view, obtaining for (1) and (2) antiferromagnetic interactions, while for (3) a ferromagnetic interaction was observed. Furthermore, to the best of our knowledge, these coordination polymers are the first heterometallic compounds based on 3d/4f cations, assembled by the ligand imidazole-4-acrylate (HIA−).

A multi-responsive luminescent indicator based on a Zn(II) metal-organic framework with “Turn on” sensing of pyridine and “Turn off” sensing of Fe3+, Cr2O72− and antibiotics in aqueous media

One water stable three-dimensional coordination polymer {[Zn(TTPA)]·1.5DMA}n(Zn-1) was successfully synthesized via solvo-thermal reaction of a bifunctional ligand 2,5-bis-(1,2,4-triazol-1-yl)-terephthalic acid (H2TTPA) and Zn(NO3)2. Single-crystal X-ray diffraction analyses proclaimed that Zn-1 is a 3D framework with one-dimensional channels long c direction. Further topological studies revealed that polymer Zn-1 characterized as a (4,4)-connected binodal net with Schläfli symbol as {42.84}. In addition, the luminescent researches indicate that complex Zn-1 exhibits not only excellent recognition abilities of Fe3+, Cr2O72− and antibiotics (NFT, NFZ and DTZ) via luminescence quenching mechanism, but also efficient “turn-on” fluorescence sensing property of pyridine. Zn-1 is the first MOF material with multi-sensing performances of Fe3+, Cr2O72−, antibiotics and pyridine in aqueous media.

Downsizing of Nanocrystals While Retaining Bistable Spin Crossover Properties in Three-Dimensional Hofmann-Type {Fe(pz)[Pt(CN)4]}-Iodine Adducts.

Mastering nanostructuration of functional materials into electronic devices is presently an essential task in materials science. This is particularly relevant for spin crossover (SCO) compounds, whose properties are extremely sensitive to size reduction. Indeed, the search for materials displaying strong cooperative hysteretic SCO properties operative at the nanoscale close near room temperature is extremely challenging. In this context, we describe here the synthesis and characterization of 20-30 nm surfactant-free nanocrystals of the FeII Hofmann-type polymer {FeII(pz)[PtII,IVIx(CN)4]} (pz = pyrazine), which affords the first example of a robust three-dimensional coordination polymer, substantially keeping operational thermally induced SCO bistability at such a scale.

Role of the Auxiliary Ligand in the Spontaneous Resolution of Enantiomers in Three-Dimensional Coordination Polymers.

Four pairs of chiral 3D coordination polymers (CPs), [Zn2(BDC)(lac)(DMF)]·guest (2) (H2BDC = benzene dicarboxylic acid; H2lac = lactic acid; guest = 1.5DMF + i-PrOH), [Co2(BDC)(lac)(DMF)]·guest (3) (guest = DMF + 2H2O), [Fe4(BDC)3(lac)2(DMF)2](CO3)·guest (4) (guest = DMF + 2H2O), and {Zn11(BPDC)6(lac)6[NH2(CH3)2]2}·guest (H2BPDC = 3,3'-biphenyldicarboxylic acid; guest = 6DMF + 18H2O) (5), are prepared through the reactions of racemic lactic acid (rac-H2lac) with different metal ions and auxiliary ligands. Structural analyses and DFT calculations reveal that forming more and stronger coordination bonds between the auxiliary ligand and metal ions is more conducive to the spontaneous resolution of enantiomers in 3D CPs than simply increasing the entropy of the auxiliary ligand itself.

A New Systematic Construction of Novel Three-Dimensional Spin Crossover Coordination Polymers Based on the [AgI 2(CN)3] Building Unit.

New three-dimensional spin crossover (SCO) coordination polymers systematically constructed by the novel building unit [AgI2(CN)3], FeII(3-Br-5-CH3pyridine)2[AgI2(CN)3][AgI(CN)2] (1), FeII(3-Br-5-Clpyridine)2[AgI2(CN)3][AgI(CN)2] (2), and FeII(3,5-Brpyridine)2[AgI2(CN)3][AgI(CN)2] (3), have been synthesized and characterized. The bismonodentate binuclear [Ag2(CN)3]− and mononuclear [AgI(CN)2]− units and FeII atoms assemble to form a 3D network structure. The structures of 1–3 are crystallographically identical, which made up the triply interpenetration combined with complicated intermolecular interactions including Ag···Ag, Ag···X (pyridine substituents) and π-stacking interactions. Magnetic and differential scanning calorimetry studies were performed for 1–3. These compounds display a similar SCO behavior, while the critical temperatures (Tc) are shifted by the substituent effect. Due to the identical structures of 1–3, the order of Tc clearly corresponds with the Hammett constant.

A new Co(II)-containing coordination polymer: treatment activity on sepsis mice by activating the NLRP3 inflammatory pathway

The solvothermal reaction between H4L, the rigid 2,6-di(2′,5′-dicarboxylphenyl)pyridine ligand, and Co(NO3)2·6H2O in water and DMF results in generation of a three-dimensional (3 D) coordination polymer (CP), [Co4(L)2(H2O)4] n ·4DMF·H2O (1, DMF = N,N-dimethylformamide), with Co(II) ions as nodes. The characterization shows that 1 has a 3 D framework structure based on tetranuclear [Co4(μ1-COO)(μ2-COO)6], whose framework could be simplified into a binodal (3,6)-linked three-dimensional network with point symbol (42·6)2(44·62·88·10). The assessment of its application on sepsis mice was implemented and the detailed mechanism was studied. First, the relative expression of NLRP3 and ASC was detected via real time RT-PCR (reverse transcription-polymerase chain reaction) assay after treatment with 1. Subsequently, the enzyme-linked immunosorbent assay was performed and the IL-18 (interleukin-18) and IL-1β (interleukin-1β) contents were detected after treatment with 1. Molecular docking simulation confirmed that the biological activity came from the hydrogen bond that was formed between carboxyl group and the active site.

Photoconductive Coordination Polymer with a Lead-Sulfur Two-Dimensional Coordination Sheet Structure.

Coordination polymers with metal-sulfur (M-S) bonds in their nodes have interesting optical properties and can be used as photocatalysts for water splitting. A wide range of inorganic-organic hybrid materials with M-S bonds have been prepared in recent years. However, there is a dearth of structural information because of their low crystallinity, which has hampered the understanding of their underlying chemistry and physics. Thus, we conducted a structural study of a novel, highly crystalline coordination polymer with M-S bonds. Theoretical calculations were performed to elucidate its photoconductivity mechanism. The photoconductive, three-dimensional coordination polymer [Pb(tadt)]n (denoted as KGF-9; tadt = 1,3,4-thiadiazole-2,5-dithiolate) was synthesized and confirmed to have a three-dimensional structure containing a two-dimensional Pb-S framework by single-crystal X-ray diffraction. We also performed diffuse-reflectance ultraviolet-visible-near-infrared spectroscopy, time-resolved microwave conductivity, and photoelectron yield spectroscopy measurements on the bulk powder samples, as well as first-principles calculations. Additionally, direct-current photoconductivity measurements were conducted on a single-crystal sample.

A novel [Dy4(OH)4]-based porous coordination polymer with double-wall structure: Topology structure, fluorescence and magnetic properties

A novel [Dy4(OH)4]-based porous coordination polymer with double-wall structure, [Dy(OH)(cppc)]n (1) (H2cppc = 5-(4-carboxyphenyl)pyridine-2-carboxylic acid), has been successfully obtained through solvo-thermal method and characterized by elemental analysis, IR spectrum, powder X-ray diffraction, single-crystal X-ray diffraction and thermal analysis. Structure analysis shows compound 1 is a three-dimensional porous coordination polymer with double-wall structure constructed by [Dy4(OH)4]8+ cubane-like units and (cppc)2− anions, in which one-dimensional square channels with the dimensions 11.78 × 11.78 Å2 are observed. Topology analysis reveals compound 1 has an unprecedented (3, 12)-connected topology net with Schlafli symbol {420.628.818}{43}4. Thermal analysis indicates the framework of compound 1 kept thermally stable until 370 °C. Fluorescent experiment indicates that compound 1 show apparently blue light emission in the solid state. Variable-temperature magnetic susceptibility measurement indicates strong antiferromagnetic interactions in [Dy4(OH)4]8+ SBU for compound 1.

A series of 2D and 3D coordination polymers containing multicore Mn-carboxyl chain and flexible polycarboxylate ligands: synthesis, structure, and magnetic properties

We report the synthesis, crystal structures, and magnetic properties of a series of two-dimensional (2-D) and three-dimensional (3-D) coordination polymers (CPs). A solvothermal reaction of manganese metal salts with 4,4′-oxydibenzoic acid (H2oba), 4,4′-methylenebis(oxy) dibenzoic acid (H2mba), 4,4′-(propane-1,3-diylbis (oxy))dibenzoic acid (H2pba) or 1,4-bis (1H-imidazol-1-yl)-butane (bib) gives five new non-interpenetrating CPs, [Mn2(oba)2(CH3OH)(H2O)] (1), [Mn6(oba)6(bib)(DMF)2(H2O)4] · (DMF)2(CH3OH) (2), [Mn4(mba)4(bib)(CH3OH)] (3), [Mn7(pba)7 (bib)(H2O)4] · (H2O)3(DMA)(CH3OH)0.5 (4), and [Mn7(pba)7(H2O)6](DMA)3 (5). The X-ray crystal structural analyses revealed that 1, 4, and 5 are 2-D layers, whereas 2 and 3 are 3-D frameworks with 1-D Mn-carboxylate chains. In 1, 2, 4, and 5, the 1-D Mn-carboxylate chains are formed by flexible carboxylate ligands and Mn ions; these were then linked by organic ligands in different directions, leading to the formation of 2-D and 3-D frameworks. Furthermore, IR, PXRD, elemental analysis, TGA, and magnetic properties have been investigated.

A Cu(II)-containing coordination polymer for efficient removal of Hg(II) from water and treatment on viral myocarditis by reducing the inflammatory response in the cardiomyocytes

Reaction between 1,3,5-tris(triazol-1-ylmethyl)-2,4,6-trimethylbenzene (TTTMB), KSCN and Cu(NO3)2·3H2O results in {[Cu3(TTTMB)4 (SCN)6]·3.5H2O}n (1), a special three-dimensional coordination polymer of Cu(II). The resulting product can selectively and efficiently adsorb Hg(II) ion in water solution, and the saturation ability of adsorption for the reactant is 439.8 mg·g−1. After treating mice with viral myocarditis, the values of the left ventricular fractional shortening (LVFS) and the left ventricular ejection fraction (LVEF) were detected. Furthermore, the inflammatory response in the cardiomyocytes was measured with an enzyme linked immunosorbent assay (ELISA) detection kit.

Extending Libraries of Extremely Localized Molecular Orbitals to Metal Organic Frameworks: A Preliminary Investigation

Libraries of extremely localized molecular orbitals (ELMOs) have been recently assembled to reconstruct approximate wavefunctions of very large biological systems, such as polypeptides and proteins. In this paper, we investigate for the first time the possibility of using ELMO transferability to also quickly obtain wavefunctions, electron densities, and electrostatic potentials of three-dimensional coordination polymers such as metal organic frameworks (MOFs). To accomplish this task, we propose a protocol that, in addition to exploiting the usual exportability of extremely localized molecular orbitals, also takes advantage of the novel QM/ELMO (quantum mechanics/extremely localized molecular orbital) approach to properly describe the secondary building units of MOFs. As a benchmark test, our technique has been applied to the well-known metal organic framework HKUST-1 ({Cu3(BTC)2}n, with BTC=1,3,5-benzenetricarboxylate) to quickly calculate electrostatic potential maps in the small and large cavities inside the network. On the basis of the obtained results, we envisage further improvements and applications of this strategy, which can be also seen as a starting point to perform less computationally expensive quantum mechanical calculations on metal organic frameworks with the goal of investigating transformation phenomena such as chemisorption.

Homochiral three-dimensional noncentrosymmetric lanthanide coordination polymers directed by chiral linkers: syntheses, crystal structures, and optical properties

Novel enantiomorphic lanthanide–organic coordination polymers directed by the chiral organic linkers exhibit second-harmonic generation.

Synthesis, structure, and properties of two coordination polymers constructed from 5-(isonicotinamido)isophthalic acid

Two three-dimensional (3D) coordination polymers, viz. [Ni(INAIP)(Him)(H2O)]·H2O (1) and [Fe(INAIP)(H2O)2]·H2O (2), were synthesized by reaction of 5-(isonicotinamido)isophthalic acid (H2INAIP), NiSO4·6H2O/FeSO4·7H2O, and N-donor ligands, namely 1H-imidazole or 4,4′-bipyridine, under hydrothermal conditions. Single-crystal X-ray diffraction analysis indicated that [Ni(INAIP)(Him)(H2O)]·H2O has a two-dimensional (2D) layer network structure with (6, 3) topology, while 2 shows a 3D fourfold interpenetrating framework with (103-b) topology. The thermal stability and magnetic and adsorption behavior in solid state of the complexes were investigated in detail. Moreover, the photocatalytic degradation of methylene blue (MB) over complex 1 was studied.

Structural diversity induced by ligand geometry: From two-dimensional to three-dimensional coordination polymers with pyridine

Two coordination polymers with two-dimensional and three-dimensional structures are, {[Zn3(bdc)3(py)2]·2NMP}n (1) (H2bdc = 1,4-benzenedicarboxylic acid) and [Zn2(NO3−)(btc)(nmp)2(py)]n (2) (H3btc = 1,3,5-benzenetricarboxylic acid), synthesized by hot-solution reactions of Zn(NO3)2·6H2O, pyridine (py) and two different ligands in N-methylpyrrolidone (NMP). {[Zn3(bdc)3(py)2]·2NMP}n exhibits two-dimensional networks with trizinc subunits [Zn3(COO)6py2] stacking with a layer-by-layer alignment, and there are strong π–π interactions involving py from adjacent layers. [Zn2(NO3−)(btc)(nmp)2(py)]n has a three-dimensional structure containing two independent zinc ions, tetrahedral ZnO4 and octahedral ZnNO5. Based on X-ray studies, the coordination polymers {[Zn3(bdc)3(py)2]·2NMP}n (1) have a porous structure with NMP guest molecules. In contrast, X-ray studies revealed that coordination polymer [Zn2(NO3−)(btc)(nmp)2(py)]n (2) had a larger void that was inhabited by coordinated py and NMP. In addition, the form of the two coordination polymers changed from two-dimensional to three-dimensional with transformation of the ligand geometry.

STRUCTURE AND LUMINESCENT PROPERTIES OF COORDINATION POLYMERS CONTAINING LEAD(II) AND THIOPHENE LIGANDS

Three new metal-organic framework polymers [Pb2(btdc)2] (1), [Pb3(ttdc)3(dma)2] (2), and [Pb(ttdc)(dma)] (3) (H2btdc = 2,2′-bithiophene-5,5′-dicarboxylic acid, H2ttdc = thieno[3,2-b]thiophene-2,5-dicarboxylic acid, dma = N,N-dimethylacetamide) are synthesized under solvatothermal conditions. The compounds are characterized by single crystal and powder X-ray diffraction, elemental, thermogravimetric, and IR spectroscopic analyses. All three compounds are three-dimensional coordination polymers with layered (1) or chain (2, 3) motifs. The study of luminescent properties reveals the intraligand nature of radiative transitions. For 1 luminescence quenching is observed because of the strengthening of vibrational states and long-range interactions between π-systems of thiophene groups. The luminescence spectrum of 2 contains two bands corresponding to two types of ttdc2– ligands with principally different structural environments. For the ligands isolated from each other the position of the luminescence maximum corresponds to that of the free ttdc2– ion. For the ligands associated in closely packed chains by continuous π-stacking the appearance of a new maximum in the red range is observed, which is due to the delocalization of electron orbitals.

Porous and Nonporous Coordination Polymers Induced by Pseudohalide Ions for Luminescence and Gas Sorption.

The three-dimensional (3D) coordination polymers [Cd(tpmd)(NCX)2]n [X = O (1), S (2), and BH3 (3); tpmd = N,N,N',N'-tetrakis(pyridin-4-yl)methanediamine] have been determined to display their network structures through coordinated anionic ligands. Polymers 1 and 2 show nonporous structures, whereas polymer 3 shows a porous coordination framework. On the basis of the Cd(II) network structures, the 3D coordination polymer [Zn(tpmd)(NCBH3)2]n·nMeOH (4) was self-assembled. In the cases of polymers 1 and 2, pseudohalide ions acted to form nonporous network structures; however, in polymers 3 and 4, NCBH3- helps to construct porous network structures. Polymers 1-4 show strong ultraviolet luminescence emissions, depending on the pseudohalide ions present, compared to the tpmd ligands. Interestingly, coordination polymers 3 and 4 that possess NCBH3- ions exhibit high porosities and gas sorption properties. The polymers appeared to absorb N2, H2, CO2, and CH4. In the case of polymer 4, the structure is almost identical with that of polymer 3, except for the Cd(II) ion. However, polymer 4 has a larger void volume and higher gas absorption ability for N2 gas than polymer 3. For the sorption of gases, polymers 3 and 4 showed similar behaviors.

Structures of five salt forms of disulfonated monoazo dyes.

The structures of five s-block metal salt forms of three disulfonated monoazo dyes are presented. These are poly[di-μ-aqua-diaqua[μ4-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)]disodium(I)], [Na2(C12H8N2O6S2)(H2O)4]n, (I), catena-poly[[tetraaquacalcium(II)]-μ-3,3'-(diazane-1,2-diyl)bis(benzenesulfonato)], [Ca(C12H8N2O6S2)(H2O)4]n, (II), catena-poly[[[diaquacalcium(II)]-μ-2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] dihydrate], {[Na(C12H10N3O6S2)(H2O)2]·2H2O}n, (III), hexaaquamagnesium bis[2-(4-amino-3-sulfonatophenyl)-1-(4-sulfonatophenyl)diazenium] octahydrate, [Mg(H2O)6](C12H10N3O6S2)2·8H2O, (IV), and poly[[{μ2-4-[2-(4-amino-2-methyl-5-methoxyphenyl)diazen-1-yl]benzene-1,3-disulfonato}di-μ-aqua-diaquabarium(II)] dihydrate], {[Ba(C14H13N3O7S2)(H2O)4]·2H2O}n, (V). Compound (III) is that obtained on crystallizing the commercial dyestuff Acid Yellow 9 [74543-21-8]. The Mg species is a solvent-separated ion-pair structure and the others are all coordination polymers with bonds from the metal atoms to sulfonate groups. Compound (I) is a three-dimensional coordination polymer, (V) is a two-dimensional coordination polymer and both (II) and (III) are one-dimensional coordination polymers. The coordination behaviour of the azo ligands and the water ligands, the dimensionality of the coordination polymers and the overall packing motifs of these five structures are contrasted to those of monosulfonate monoazo congers. It is found that (I) and (II) adopt similar structural types to those of monosulfonate species but that the other three structures do not.

Stepwise Assembly of an Electroactive Framework from a Co6 S8 Superatomic Metalloligand and Cuprous Iodide Building Units.

The design of metal-organic frameworks (MOFs) that incorporate more than one metal cluster constituent is a challenging task. Conventional one-pot reaction protocols require judicious selection of ligand and metal ion precursors, yet remain unpredictable. Stable, preformed nanoclusters, with ligand shells that can undergo additional coordination-driven reactions, provide a platform for assembling multi-cluster solids with precision. Herein, a discrete Co6 S8 (PTA)6 (PTA=1,3,5-triaza-7-phosphaadamantane) superatomic-metalloligand is assembled into a three-dimensional (3D) coordination polymer comprising Cu4 I4 secondary building units (SBUs). The resulting heterobimetallic framework (1) contains two distinct cluster constituents and bifunctional PTA linkers. Solid-state diffuse reflectance studies reveal that 1 is an optical semiconductor with a band-gap of 1.59 eV. Framework-modified electrodes exhibit reversible redox behavior in the solid state arising from the Co6 S8 superatoms, which remain intact during framework synthesis.

Three-dimensional homochiral coordination polymers of Eu(III) and Tb(III): Synthesis, structure determination, and optical properties

Self-assembly of the corresponding europium and terbium salts with designed chiral ligand (S)-5-((2-carboxy-5-oxopyrrolidin-1-yl)methyl)isophthalic acid (H3L) generated two novel 3D coordination polymers {[Eu(L)]·0.5CH3CN}n (1) and {[Tb(L)]·0.5CH3CN}n (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are isostructural metal-organic frameworks built from four-stranded helixes. Complexes 1 and 2 are intriguing homochiral porous architectures with 6,6-connected (48∙66∙8)(413∙62) topology, whose homochirality was further confirmed by their solid-state circular dichroism spectra. Thermal analyses disclose that the desolvated frameworks of 1 and 2 can maintain their structural stability below 370 ​°C. Solid-state photoluminescence studies show that 1 and 2 exhibit strong characteristic Eu(III) and Tb(III) emissions with long lifetimes of 1.31 and 1.35 ​ms, respectively. In addition, 1 and 2 also exhibit significant second harmonic generation activities with their intensities of about 0.29 and 0.31 times larger than that of potassium dihydrogenphosphate, respectively. Very importantly, the excellent thermostabilities and strong red and green emissions of 1 and 2 are of great significance for further exploration of their applications in optical devices.