Flexible N-donor Ligands Research Articles

Retraction of “Two mixed-ligand coordination polymers based on 2,5-thiophenedicarboxylic acid and flexible N-donor ligands: The protective effect on periodontitis via reducing the release of IL-1β and TNF-α”

Retraction of “Two mixed-ligand coordination polymers based on 2,5-thiophenedicarboxylic acid and flexible N-donor ligands: The protective effect on periodontitis via reducing the release of IL-1β and TNF-α”

Studying the impact of NCS− anion and the steric hindrance of flexible N-donor ligands on the crystal engineering of the mercury(II) coordination polymer

Studying the impact of NCS− anion and the steric hindrance of flexible N-donor ligands on the crystal engineering of the mercury(II) coordination polymer

Self-assembly of three novel entangled polyoxometalate-based coordination polymers with redox properties

Three novel entangled coordination polymers (CPs), namely, [Cu4(BPB)5(HPW12O40)2]·2H2O (JOU-15), [Cu3(BPB)3PW12O40] (JOU-16), and [Cu3(BPBP)3PW12O40] (JOU-17), have been successfully synthesized by combining flexible N-donor ligands and Keggin type polyoxometalates with copper ion under hydrothermal conditions. Structural characterizations show that JOU-15 features an unusual 1D + 1D → 2D entangled network with the coexistence of polycatenation and interdigitation. JOU-16 exhibits a fascinating self-catenated three-dimensional framework with a new point symbol of (44·610·8)(65·8)(66). JOU-17 displays a novel 1D + 3D + 3D → 3D entangled framework with features of both polycatenation and polythreading. In addition, the electrochemical properties of these compounds have also been studied.

Structural diversity and photoluminescent properties of two zinc coordination polymers based on 5-i-propoxyisophthalate and flexible N-donor ligands

Two new zinc coordination polymers, {[Zn(iPrIPA)(bpa)]⋅2H2O}n (1) and [Zn2(iPrIPA)2(bpp)]n (2) (iPrIPA = 5-i-propoxyisophthalate, bpa = 1,2-bis(4-pyridyl) ethane, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized under hydrothermal conditions. Complexes 1 and 2 represent 3-D polythreaded supra molecular architecture consisting of corrugated 2D layer for complexes 1 and a 2D network consisting of alternating Zn1 binuclear and paddel-wheel Zn2 binuclear units for compound 2. The structural comparison of these two complexes demonstrates that the characteristics of auxiliary ligands play a key role in governing the coordination motifs and the final supramolecular lattices. Fluorescence emission and room temperature phosphorescence (RTP) behavior of 1 and 2 were also investigated.

RETRACTED ARTICLE: Two Mixed-Ligand Co(II)-Based Coordination Polymers: Treatment Activity on Pediatric Asthma Via Inducing Eosinophil Apoptosis Through Down-Regulating Bcl-2 Expression

In this work, two coordination polymers containing Co(II) ions as nodes, namely, [Co(NDC)(L)(H2O)]n (1, H2NDC = 1,4-naphthalene dicarboxylic acid) and [Co(DCTP)(L)·(H2O)2]n (2, H2DCTP = 2,5-dichloroterephthalic acid) were prepared based on 1,4-bis(5,6-dimethylbenzimidazole)butane (L), the flexible N-donor ligand and different dicarboxylate ligand. Their treatment activity on the pediatric asthma was evaluated in the biological research. Firstly, the enzyme linked immunosorbent assay (ELISA) detection was carried out to determine the IL-1β and TNF-α content in the bronchus. The inflammatory response in the bronchial epithelial cells was determined by the real time reverse transcription-polymerase chain reaction (RT-PCR). After that, the eosinophil apoptosis in the airway was measured. Finally, the western was performed for the confirmation of eosinophil apoptosis by detecting Bcl-2 and caspase-3.

Two ZnII-based MOFs constructed with biphenyl-2,2′,5,5′-tetracarboxylic acid and flexible N-donor ligands: syntheses, structures and properties

Two new Zn2+-based metal-organic frameworks (MOFs) based on biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. H4(o,m-bpta), and N-donor ligands, namely, poly[[(μ4-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,3-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn2(C16H6O8)(C14H14N4)2]·C3H7NO·2H2O}n or {[Zn2(o,m-bpta)(1,3-bimb)2]·C3H7NO·2H2O}n (1) {1,3-bimb = [1,3-phenylenebis(methylene)]bis(1H-imidazole)}, and poly[[(μ4-biphenyl-2,2',5,5'-tetracarboxylato)bis{[1,4-phenylenebis(methylene)]bis(1H-imidazole)}dizinc(II)] monohydrate], {[Zn2(C16H6O8)(C14H14N4)2]·H2O}n or {[Zn2(o,m-bpta)(1,4-bimb)2]·H2O}n (2) {1,4-bimb = [1,4-phenylenebis(methylene)]bis(1H-imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. Structurally, the (o,m-bpta)4- ligands are fully deprotonated and combine with Zn2+ ions in μ4-coordination modes. Complex 1 is a (3,4)-connected porous network with honeycomb-like [Zn2(o,m-bpta)]n sheets formed by 4-connected (o,m-bpta)4- ligands. Complex 2 exhibits a (2,4)-connected network formed by 4-connected (o,m-bpta)4- ligands linking Zn2+ ions in left-handed helical chains. The cis-configured 1,3-bimb and 1,4-bimb ligands bridge Zn2+ ions to form multi-membered [Zn2(bimb)2] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H4(o,m-bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C2v polar point group.

Two mixed-ligand coordination polymers based on 2,5-thiophenedicarboxylic acid and flexible N-donor ligands: the protective effect on periodontitis via reducing the release of IL-1β and TNF-α

Abstract Two novel mixed-ligand coordination polymers, {[Co(tdc)(btrp)]·0.67DMF} n (1) and {[Zn2(bimb)2(tdc)2]·2H2O} n (2) involving 2,5-thiophenedicarboxylate (H2tdc), and bitopic flexible N-donor ligands, 1,3-bis(1,2,4-triazol-1-yl)propane (btrp) and 1,4-bis((1H-benzo[d]imidazol-1-yl)methyl)benzene (bimb), have been synthesized by the hydrothermal method and characterized via IR, elemental analysis, thermal analysis, and powder X-ray diffraction. The biological functional studies were performed; the treatment activity of the compounds on periodontitis and the specific mechanism was explored. First, the real-time RT-PCR was carried out to determine the inflammatory genes nf-κb and p53 relative expression in periodontal mucosal cells after treating with compounds 1 and 2. Then, the level of the inflammatory cytokine in the gingival crevicular fluid after treating with compounds was also determined by the ELISA detection kit.

Two CoII coordination polymers of biphenyl-2,2′,5,5′-tetracarboxylic acid with flexible N-donor ligands: syntheses, structures and magnetic properties

Two CoII-based coordination polymers, namely poly[(μ4-biphenyl-2,2',5,5'-tetracarboxylato){μ2-1,3-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)], [Co2(C16H6O8)(C14H14N4)2]n or [Co2(o,m-bpta)(1,3-bimb)2]n (I), and poly[[aqua(μ4-biphenyl-2,2',5,5'-tetracarboxylato){1,4-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co2(C16H6O8)(C14H14N4)2(H2O)2]·4H2O}n or {[Co2(o,m-bpta)(1,4-bimb)2(H2O)2]·4H2O}n (II), were synthesized from a mixture of biphenyl-2,2',5,5'-tetracarboxylic acid, i.e. [H4(o,m-bpta)], CoCl2·6H2O and N-donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. The bridging (o,m-bpta)4- ligands combine with CoII ions in different μ4-coordination modes, leading to the formation of one-dimensional chains. The central CoII atoms display tetrahedral [CoN2O2] and octahedral [CoN2O4] geometries in I and II, respectively. The bis[(1H-imidazol-1-yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect CoII ions, thus forming two three-dimensional (3D) networks. Complex I shows a (2,4)-connected 3D network with left- and right-handed helical chains constructed by (o,m-bpta)4- ligands. Complex II is a (4,4)-connected 3D novel network with ribbon-like chains formed by (o,m-bpta)4- linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co...Co distances. An attempt has been made to fit the χMT results to the magnetic formulae for mononuclear CoII complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the CoII ions.

Two 2D-MOFs based on two flexible ligands: structural control and fluorescence sensing on FeIII cation and CrVI-containing anions

Based on flexible ligands 4,4′-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H3cpbda), two flexible N-donor ligands with the similar molecular length, 3-bis(1H-imidazol −1-yl)propane (bip) and 1,3-bis(pyridin-4-yl)propane (bpp), were introduced to assemble MOFs with different metals. Two 2D-MOFs, [Cd1.5(cpbda)(bip)0.5(H2O)]n (1) and [Cu(Hcpbda)(bpp)(H2O)]n (2), were successfully synthesized and characterized by single-crystal X-ray diffraction, power X-ray diffraction, thermal-gravimetric analysis and fluorescence spectroscopy. The different terminal functional groups (imidazole and pyridine) in bip and bpp ligands generate different molecular coordination angels, which show diverse terminal type and bridged type in two 2D structures. The sensing results of 1 on metal cations and anions and magnetic property of 2 were studied. The influences of various N-donor ligands in assembly of flexible MOFs accompany with H3cpbda are also summarized.

A new copper(II) supramolecular coordination polymer and a dinuclear compound with multifunctional 2-amino-5-sulfobenzoic acid and flexible N-donor ligands: synthesis, structure and characterization.

Multifunctional 2-amino-5-sulfobenzoic acid (H2afsb) can exhibit a variety of roles during the construction of supramolecular coordination polymers. The pendant carboxylic acid, sulfonic acid and amino groups could not only play a role in directing bonding but could also have the potential to act as hydrogen-bond donors and acceptors, resulting in extended high-dimensional supramolecular networks. Two new CuII coordination compounds, namely catena-poly[[[diaquacopper(II)]-μ-1,6-bis(1H-1,2,4-triazol-1-yl)hexane-κ2N4:N4'] bis(3-amino-4-carboxybenzenesulfonate) dihydrate], {[Cu(C10H16N6)2(H2O)2](C7H6NO5S)2·2H2O}n or {[Cu(bth)2(H2O)2](Hafsb)2·2H2O}n, (1), and bis(μ-2-amino-5-sulfonatobenzoato-κ2O1:O1')bis{μ-1,2-bis[(1H-imidazol-1-yl)methyl]benzene-κ2N3:N3'}bis[aquacopper(II)] trihydrate, [Cu2(C7H5NO5S)2(C14H14N4)2(H2O)2]·3H2O or [Cu2(afsb)2(obix)2(H2O)2]·3H2O, (2), have been obtained through the assembly between H2afsb and the CuII ion in the presence of the flexible N-donor ligands 1,6-bis(1H-1,2,4-triazol-1-yl)hexane (bth) and 1,2-bis[(1H-1,2,4-triazol-1-yl)methyl]benzene (obix), respectively. Compound (1) consists of a cationic coordination polymeric chain and 3-amino-4-carboxybenzenesulfonate (Hafsb-) anions. Compound (2) exhibits an asymmetric dinuclear structure. There are hydrogen-bonded networks within the lattices of (1) and (2). Interestingly, both (1) and (2) exhibit reversible dehydration-rehydration behaviour.

Interpenetrated and Polythreaded CoII-Organic Frameworks as a Supercapacitor Electrode Material with Ultrahigh Capacity and Excellent Energy Delivery Efficiency.

Synthesizing kinetically stable coordination polymers (CPs) through ligand functionalization can effectively improve their supercapacitive performances. Herein, we have successfully synthesized three novel and topological Co-CPs by varying the flexible N-donor ligand and inorganic anions, namely, interpenetrated [Co(HTATB)( o-bib)]·H2O, extended two-dimensional (2D) layered Co(HTATB)( m-bib)·2H2O, and three-dimensional (3D) Co(HTATB)( m-bib), where bib is the flexible N-donor bis((1 H-imidazol-1-yl)methyl)benzene linker (where o- and m- refer to ortho and meta positions, respectively) ligand and HTATB is the partial deprotonation mode from 4,4',4″- s-triazine-2,4,6-triyl-tribenzoic acid. Various Co-CPs have been directly applied in the field of supercapacitors. All these framework materials exhibit high capacitance, excellent energy delivery efficiency, and good cycling performance. For instance, the maximum specific capacitance for penetrated 3D networks is 2572 F g-1 at 2.0 A g-1, and the mean energy delivery efficiency is up to 92.7% based on the tested current densities. Compared with extensional 2D layered and 3D networks, the 3D interpenetrated and polythreaded architectures could provide more active sites and thus promote fast charging and discharging processes. Furthermore, the Li+ uptake-release abilities of the Co-based CPs are also investigated, and the initial discharge capacity value for the 3D interpenetrated structures can reach up to 1792 mA h g-1 at a current density of 50 mA g-1.

Synthesis, Crystal Structure, and Luminescent Properties of Ag(I) Coordination Polymer with Tricarboxylic Acid and Flexible N-donor Ligand

The reaction of AgNO3 with combinations of 1,3-bis(4-pyridyl)propane (bpp) and 1,3,5-benzenetricarboxylic acid (H3btc) in aqueous alcohol/ammonia at room temperature produces crystals of {[Ag6(H2O)2(bpp)6] · (btc)2 · 25H2O} n (Ι). Single crystal X-ray diffraction analysis reveals that the complex Ι consists of 1D infinite cationic chains of [Ag(bpp)] n n+ and [Ag(H2O)(bpp)] n n+ which are further linked into the cation layer of [Ag(bpp)] n n+ by Ag···π interactions. The noncoordinated btc3− serves as template driving surrounding water molecules to aggregate into the anionic water layer. The neighboring anionic water layer and cationic layer were further alternately joined into a 3D sandwich-like framework by hydrogen bonding. In addition, the luminescent properties of Ι were investigated.

Syntheses, structures and luminescence of three copper(I) cyanide coordination polymers incorporating flexible N-donor ligands

Three copper(I) cyanide coordination polymers, namely [Cu8(CN)8(btmb)2]n (1), [Cu(CN)(btmb)0.5]n (2) and [Cu2(CN)2(dpa)]n (3) (btmb=1,4-bis(1,2,4-triazol-1-ylmethyl)benzene, dpa=di(4-pyridyl)amine), were synthesized under hydrothermal conditions and characterized by elemental analyses, IR spectra, PXRD and thermogravimetric analyses. Single-crystal X-ray diffraction analyses reveal that complex 1 is an interesting 2D double-layered network constructing from eight distinct Cu(I) centers, eight μ2-cyanides and two tetradentate cis-btmb ligands. Complex 2 is a ladder-like coordination polymer assembled by CuCN linear chain and bidentate trans-btmb linker. Complex 3 has a 2D wave-like network constructing from CuCN zigzag chain and V-shape dpa spacer. These coordination polymers are thermally stable up to 270–300°C. They emit blue luminescence originating from ligand-centered emission.

A series of 1-D, 2-D and 3-D coordination polymers self-assembled from a flexible dicarboxylate and mixed N-donor ligands: syntheses, structural diversity, and luminescent properties

We have synthesized a series of metal–organic coordination frameworks under solvothermal conditions, formulated as [Cu(L)(phen)](1), [Co2(L)2(bib)]·CH3OH(2), [Co(L)(btmb)0.5](3), [Zn(L)(bib)]·2H2O(4), [Cu(L)(bib)]·DMF(5), and [Mn4(L)4(bimb)(CH3OH)](6) based on a flexible multicarboxylic bridging ligand 4,4′-methylenebis(oxy)-dibenzoic acid (H2L) and flexible N-donor ligands 1,4-bis (1H-imidazol-1-yl)-butane (bib), 1,4-bis(1H-1,2,4-triazol- 1-ylmethyl)benzene (btmb), and 1,4-bis(1H-imidazol-1-ylmethyl)benzene (bimb). The structures of the frameworks have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The crystal structure determinations reveal that 1 has a 1-D Z-shape chain. Compounds 2 and 3 are 2-D twofold parallel interpenetrating 4-connected net with the Schläfli symbol {44·62}. Compound 4 is a 2-D threefold parallel interpenetrating 4-connected nets with the Schläfli symbol {44·62}. Compound 5 is 3-D 4-connected net with the Schläfli symbol {65·8}. Compound 6 is characterized by a three-dimensional framework with one-dimensional homogeneous Mn-carboxylate chain. We found that flexible carboxylate ligands have different coordination modes under different synthetic conditions. The flexible skeleton of ligands and the coordination angle between the ligand and the metal ion is described. The luminescence and thermogravimetric properties of these compounds have been investigated.

ChemInform Abstract: Tuning the Topology of Hybrid Inorganic—Organic Materials Based on the Study of Flexible Ligands and Negative Charge of Polyoxometalates: A Crystal Engineering Perspective

AbstractReview: 159 refs.

Two 3D ZnII Metal–Organic Frameworks with 3- and 8-Fold Interpenetration: Syntheses, Structures, Photodegradation, and Photoluminescent Properties

Two novel coordination polymers, namely {[Zn(sbdc)(bmib)]·0.4H2O}n (1) and {[Zn(sbdc)(bibd)]·DMF}n (2) (H2sbdc = 4,4′-stilbenedicarboxylic, bmib = 1,4-bis(2-methylimidazol-1-yl)butane, bibd = 1,1′-(1,4-butanediyl)bis(imidazole), DMF = N,N-dimethylformamide), have been acquired under solvothermal conditions, and have been characterised by elemental analysis, infrared spectra, thermogravimetric analysis, and single-crystal X-ray diffraction (XRD). Single-crystal XRD analysis reveals that 1 shows eight-fold interpenetrating 3D frameworks with a four-connected (66) sqc6 topology and 2 displays four-connected three-fold interpenetrating 3D frameworks. The flexible N-donor ligands play an important role in the construction of the final topological structures for 1 and 2. Furthermore, 1 and 2 exhibit good photodegradation capability and photoluminescence properties.

Syntheses, structures and magnetism of four Ni(II)/Co(II) interpenetrating coordination polymers based on 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine

Four novel interpenetrating coordination polymers have been hydrothermally synthesized based on a long flexible N-donor ligand (bibp) and different polycarboxylates, namely [Ni(1,3-bdc)(bibp)(H2O)]·0.5H2O (1), [Ni(btec)0.5(bibp)1.5]·H2O (2), [Co(btec)0.5(bibp)1.5]·H2O (3) and [Co(oba)(bibp)]·2H2O (4) (bibp=1,4-bis(4-(imidazole-1-yl)benzyl)piperazine, 1,3-bdc=1,3-benzenedicarboxylate, btec=1,2,4,5-benzenetetracarboxylate, oba=4,4′-oxybisbenzoate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra and TG analyses. Compound 1 shows a 2-fold interpenetrating 3D framework with CdSO4 topology. Compounds 2 and 3 exhibit 2-fold interpenetrating pcu frameworks. Compound 4 is a 2D→3D interdigitated network formed from 2D→2D threefold interpenetrating motifs. In addition, the magnetic properties of compounds 1–4 have also been investigated in the temperature range 2–300K.

Two double and triple interpenetrated Cd(II) and Zn(II) coordination polymers based on mixed O- and N-donor ligands: Syntheses, crystal structures and luminescent properties

Two interpenetrated 3D coordination polymers, namely [Cd2(tdc)2(bpp) (DMA)]n (1) and [Zn2(tdc)2(bib)2]n·2n(DMA) (2) (H2tdc = 2,5-thiophenedicarboxylic acid, bpp = 1,3-di(4-pyridyl)propane, bib = 1, 4-bis(imidazolyl)butane, DMA = N,N-dimethylacetamide), have been solvothermally synthesized by the self-assembly of flexible N-donor and dicarboxylate ligands. Single crystal X-ray diffraction analyses revealed that compound 1 features a 2-fold interpenetrated 3D framework based on dinuclear [Cd2(COO)3] subunits and can be simplified into a 6-connected pcu topology, and compound 2 features a 3-fold interpenetrated 3D framework with 4-connected dia topology. Moreover, the thermal stabilities and luminescent properties of these two compounds were also investigated.

Effect of central metals and N-donor ligands on the architectures of a series of coordination polymers based on a bis(sulfanediyl) thiadiazole diacetate

Five new transition metal coordination polymers, namely, [Co(bbbm)(BSTDA)] (1), [Co(bdmbmb)(BSTDA)(H2O)]·(H2O) (2), [Ni(bbbm)(BSTDA)(H2O)2] (3), [Ni2(3-dpyh)2(BSTDA)2(H2O)] (4) and [Cd(bbbm)1.5(BSTDA)] (5) have been synthesized from an S-/thiadiazole-containing dicarboxylate [H2BSTDA=bis(sulfanediyl) thiadiazole diacetic acid] and different flexible/semi-rigid N-donor ligands [bbbm=1,1-(1,4-butanediyl) bis-1H-benzimidazole, bdmbmb=1,4-bis(5,6-dimethylbenzimidazole-1-yl)benzene and 3-dpyh=N,N′-bis(3-pyridinecarboxamide)-1,6-hexane]. Structural analysis indicates that the title complexes present different structures although using the same S-/thiadiazole-containing dicarboxylate. Complex 1 is a 3D framework constructed from 2D (63) Co-BSTDA layers and 1D Co-bbbm chains. When the flexible bbbm in 1 was replaced by a semi-rigid bdmbmb ligand, a 2D parallelogram (4,4) network 2 derived from 1D Co-BSTDA and Co-bdmbmb single chains has been obtained. Complex 3, with NiII ion as substitute of CoII ion in 1, exhibited a 2D (4,4) network constructed form 1D Ni-BSTDA and Ni-bbbm single chains. When the bbbm in 3 was replaced by a longer and more flexible N-donor ligand 3-dpyh in 4, a 2D wave-like (4,4) layer constructed from [Ni-BSTDA]2 and [Ni-(3-dpyh)]2 double chains with bimetallic nodes was generated. While the CoII ion in 1 was substituted by CdII ion in 5, a 3D framework crossed by 2D (63) wave-like Cd-bbbm layers and 1D zigzag Cd-BSTDA chains was obtained. Structural diversity in complexes 1–5 demonstrates that the coordination characters of metal ions, the spacer length and flexibility of N-donor ligands have great influence on the final structures of the title complexes. In addition, fluorescence properties of complexes 1–5 are also reported in this paper.

Architectural chemistry of polyoxometalate-based coordination frameworks constructed from flexible N-donor ligands

Polyoxometalate-based coordination frameworks (POMCFs) constructed from flexible N-donor ligands can exhibit diverse properties and fascinating architectures, extending the families of material chemistry and structural chemistry.