Bis Imidazole Ligands Research Articles

Highly Sensitive Fluorescent Sensing for Nitrobenzene of CdII Complexes Based on Three Isomers and a Bis-Imidazole Ligand.

Detection of nitro pollutants is an important topic in environmental protection. A total of 3 Cd (II) complexes (1-3) based on 3 soft organic isomers, n-(3,5-dicarboxylato benzyloxy) benzoic acid (n = 2, 3 or 4-H3DBB), and a linear N-donor ligand, 3-bis(imidazole-l-ylmethyl) benzene (3-bibz), have been synthesized hydrothermally. Structural diversity of Complexes 1-3 displays the architectural 2D or 3D change: Complex 1 exhibits a 2D network featuring tri-nuclear metal units, Complex 2 is a 3D framework based on similar tri-nuclear metal units, and Complex 3 shows a 3D network with binuclear units. Fluorescent sensing properties exhibited in all these complexes have been discovered to detect nitrobenzene (NB) selectively and sensitively. In particular, Complex 3 possesses high sensitivity for NB with the lowest detection limit of 1.15 × 10-10 M. The results of the theoretical calculation verified the fluorescence detection mechanism of NB by these Cd-based complexes. Therefore, these Cd-based complexes might be used as excellent luminescent sensors for NB.

Multinuclear coordination compounds constructed by bis-imidazole and azide ligands. Creation of new network structures and an M2L4 cage that includes two anions

Abstract Treatment of the bis-imidazole ligand, bitb, with CuSO4·5H2O, ZnSO4·7H2O, and Co(NO3)2·6H2O in the presence of NaN3 produced [Cu2(μ-N3)2(bitb)(N3)2]n (1), [Zn(bitb)(N3)2]n (2), and [(N3)2 ⊂ Co2(bitb)4(N3)2](Me2CO)2·(H2O)4 (3). Compound 1 is a 2D coordination polymer with {Cu2(μ-N3)2}n chains in the framework. Compound 2 is a 1D coordination polymer with repetitions of the “figure-of-eight-shaped” turns. Compound 3 is an M2L4 cage compound that includes 2 N3− in the cage. Their unprecedented coordination structures are described.

Multi-responsive luminescent MOF sensor for Fe3+, CrO42− and Cr2O72− in aqueous solution based on phenylenediacetate and bis-imidazole ligand

Two metal-organic frameworks (MOFs), namely, [Zn2(m-2mbix)(HEA)2·2H2O]n (1) and { [Ni(m-2mbix)(HEA)]·3H2O}n (2) (m-2mbix = 1,3-bis(2-methylimidazol-1-ylmethyl)benzene, H2HEA = 1,2-phenylenediacetic acid), respectively, were successfully synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction analysis, elemental analysis, infrared spectroscopy and thermogravimetric analysis. Single crystal structures revealed that 1 and 2 were two-dimensional structure and two-dimensional (4,4)-topological layer structure, respectively. In addition, the complex 1 can function as a turn-off luminescent sensor to sensitively and selectively sensing Fe3+, CrO42− and Cr2O72− ions in aqueous media.

Carbazole-based bis-imidazole ligand-involved synthesis of inorganic-organic hybrid polyoxometalates as electrochemical sensors for detecting bromate and efficient catalysts for selective oxidation of thioether.

Considering the potential application on preparing electrode and catalyst materials of inorganic–organic hybrid polyoxometalates, a bis-imidazole ligand with carbazole as a connector, 3,6-di(1H-imidazol-1-yl)-9H-carbazole (L), was used for preparing inorganic–organic hybrid polyoxometalates. As a result, three complexes formulated by [NiL2(Mo2O7)] (1), [Cu(H2O)2(HL)2 (β-Mo8O26)]·H2O (2) and [Ni2(H2O)4L2 (CrMo6(OH)5O19)]·6H2O (3) were obtained successfully. Structural analysis indicated that the different polyoxoanions and metal ions showed important influences on the formation of structures. In the presence of Ni2+ ions and heptamolybdate, a 2D network constructed from Ni2+ ions and L ligands was formed in complex 1, in which the [Mo4O14]4− polyoxoanions were encapsulated. But the use of Cu2+ ions led to a 1D chain of complex 2, which was composed of [β-Mo8O26]4− polyoxoanions and mononuclear {CuL2} units. By utilizing [CrMo6(OH)5O19]4− as the inorganic building block, complex 3 showed a 2D (4, 4)-connected layer. Complexes 1–3 could be employed as electrode materials for sensing bromate with the limits of detection of 0.315 μM for 1, 0.098 μM for 2 and 0.551 μM for 3. Moreover, these complexes showed efficient catalytic activity for the selective oxidation of thioethers.

A Series of Coordination Polymers Constructed by 2-Phenylsuccinic Acid and Flexible Bis(Imidazole) Ligands: Syntheses, Structures, and Photoluminescent Properties

A Series of Coordination Polymers Constructed by 2-Phenylsuccinic Acid and Flexible Bis(Imidazole) Ligands: Syntheses, Structures, and Photoluminescent Properties

Highly stable Cd(II)-MOFs based on 2,6-naphthanlenedisulfonate and bisimidazole ligands: A new platform for selective detection of Cu2+ and efficient removal of iodine

Two new metal-organic frameworks (MOFs) namely, [Cd (nds) (bimh)2·(bimh)]n (1) and [Cd (nds) (bimb)2]n (2), (nds ​= ​2,6-naphthalenedisulfonate; bimh ​= ​1,6-bis-(imidazole-1-yl)-hexane; bimb ​= ​1,1'-(1,4-butanediyl)bis(imidazole)), have been hydrothermally synthesized. These complexes were characterized by IR spectroscopy, elemental analysis and X-ray single-crystal diffraction. Complex 1 possesses a 3D framework with 6-connected (412.63) pcu topology. Complex 2 shows a 2D layer with Schläfli symbol of (36) (46) (53). The adjacent layers are stacked offset with respect to each other, in an ABAB fashion. Both complexes 1 and 2 exhibit low detection limit and high selectivity toward Cu2+ through the luminescent quenching experiments. Further, the adsorption experiments indicate that complex 1 could efficiently remove I2 from the cyclohexane solution after 20 ​h with an adsorption capacity of 148.5 ​mg/g.

Two New Cu(II) Coordination Polymers with 2D and 1D Frameworks that Show Reversible Structural Transformations Depending on the Present Solvents

Two new CuII coordination polymers with bis-imidazole ligand, bitrb, were synthesized and characterized. Reaction of CuSO4·5H2O with bitrb in a MeOH-H2O mixed solution produced a 2D coordination polymer, while a similar reaction in a THF-MeOH mixed solution gave a 1D coordination polymer. The former compound converts to the latter in a THF-MeOH mixed solvent, while the reversed reaction proceeds in MeOH-H2O media. Their crystal structures and the reversible transformations depending on the present solvents are described.

Crystal structure and physical properties of a new two-dimensional zinc coordination polymer based on 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine and benzophenone-2,4′-dicarboxylate ligands

Abstract A new 2-dimensional (2D) zinc(II) coordination polymer based on a flexible bis(imidazole) ligand, namely, [Zn2(BIBP)(BPDC)2·DMF] n (1) BIBP is 1,4-bis(4-(imidazole-1-yl)benzyl)piperazine and H2BPDC is benzophenone-2,4′-dicarboxylic acid), has been synthesized and characterized through single-crystal X-ray diffraction, infrared (IR) spectroscopy, and elemental and thermal gravimetric analysis. Complex 1 exhibits a 2D framework oriented parallel to [0 2 1] based on [Zn(BPDC)] n chains. The fluorescence and catalytic properties of complex 1 for the photodegradation of methylene blue were investigated.

Two Mixed-ligand Coordination Polymers: Crystal Structures and Protective Effect on Ischemic Stroke by Increasing glp1r Expression.

In this study, two new mixed-ligand coordination polymers {[Co(bbi)(tdc)]·5H2O}n (1, bbi = 1,4-bis(imidazolyl)butane) and {[Cu2(bimb)(H2O)(μ3-tdc)2(DMF)2]·H2O}n (2, bimb = 4-bis(1H-imidazol-1-yl-methyl)benzene) were synthesized under the solvothermal conditions via reaction of 2,5-thiophenedicarboxylic acid (H2tdc) with the corresponding metal salts in the existence of different flexible bis-imidazole ligands (bbi for 1 and bimb for 2). The as-prepared two structures were detected via the single crystal X-ray diffraction (SXRD) and then characterized via the analysis of element, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) as well as infrared (IR) spectroscopy. Furthermore, the protective activity of the compound on the mice with ischemic stroke was evaluated. Firstly, the real time reverse transcription-polymerase chain raction (RT-PCR) was carried out to determine the effect of compounds 1 and 2 against the relative expression level of the glucagon-like peptide 1 receptors (glp1r) on the cerebrovascular endothelial cells. Next, the Morris Water Maze Experiment was also used to detect the improvement function of compounds 1 and 2 on the nice mice cognitive function.

Synthesis, Crystal Structure, and Photoluminescent Properties of Two Porous Pillared-layer Metal-organic Frameworks Constructed by Benzene-1,3,5-tricarboxylic Acid and Bisimidazole Ligands

Two pillared layer metal organic frameworks, namely {[Co3(Btc)2(Bib)3(H2O)2] · 7H2O}n(I) and {[Cd2(Btc)(Bib)2(Fma)(H2O)] · H2O}n (II), where H3Btc is benzene-1,3,5-tricarboxylic acid, Fma is formate anion and Bib is 1,4-bis(1-imidazolyl)benzene, have been successfully synthesized by solvothermal method and structurally characterized by element analysis, IR spectroscopy, as well as single crystal X-ray diffractionand power X-ray diffraction (СIF files CCDC nos. 1829267 (I), 1829266 (II)). In the complexes I and II, the full deprotonated aromatic polycarboxylate take the same coordination mode to bridging four metal ions but result in different 2D network, which are further pillared by bib ligands to form 3D architectures with piont symbol of (42.64)2(42.67.8)2(64.82) and (42.63.8)(42.64)(42.67.8), respectively. The photoluminescent property of complex II is also reported.

Two metal–organic frameworks based on 2,5-thiophenedicarboxylic acid and semi-rigid bis-imidazole ligand: Luminescence, magnetism and electrocatalytic activities

Tuning metal ion from Cd(II) to Co(II) in the presence of 2,5-thiophenedicarboxylic acid (H2tdc) and semi-rigid bis-imidazole ligand 4-bis(1H-imidazol-1-yl-methyl)benzene(bimb), two metal–organic frameworks, [Cd3(bimb)(μ4-tdc)3(DMA)2]·2DMA (1) and [Co2(bimb)(μ2-H2O)(μ3-tdc)2(DMF)2]·H2O (2), have been generated under solvothermal condition. All two frameworks with (412, 63) topology are pillared by bimb ligands, and the difference is that there exist trinuclear cadmium clusters gathered by tdc ligands in the structure of 1, but binuclear cobalt units in 2. Interestingly, with the change of metal ion from Cd(II) to Co(II), compound 1 displays good luminescent property at room temperature, and compound 2 exhibits not only antiferromagnetic interaction, but also electrocatalytic activity toward the oxidation of ascorbic acid.

Solvent-directed control over the topology of entanglement in square lattice (sql) coordination networks.

We report herein that the mode of entanglement in square lattice, sql, coordination networks formed by an extended bis-imidazole ligand, L, can be controlled by the solvent used during solvothermal synthesis. [ML2(NO3)2]n (M = Co, Ni) exhibit both parallel 2D → 2D interpenetration and, unusually, mixed entanglement (parallel-inclined 2D → 3D polycatenation).

Rational design of a boron-dipyrromethene-based fluorescent probe for detecting Pd2+ sensitively and selectively in aqueous media.

A novel fluorescent probe for Pd2+ based on the BODIPY fluorophore exploiting the PET (Photoinduced Electron Transfer) mechanism was designed and successfully synthesized. The fluorescent probe 1 was prepared by introducing m-bisimidazolylbenzene which was connected by phenyl acetylene to the BODIPY dye at the meso position. It exhibited a rapid response and high sensitivity and selectivity toward Pd2+. Probe 1 presented a rapid quenched fluorescence response in aqueous buffer media (pH 5.5) and the detection limit estimated from the titration results was 2.9 × 10-7 M. Meanwhile, other common metal ions did not interfere with the recognition process. The DFT calculation proved that coordination of bisimidazole ligands with Pd2+ effectively decreases the LUMO energy of m-bisimidazolylbenzene which was located between the HOMO and LUMO energies of the BODIPY dye leading to fluorescence quenching via the d-PET mechanism.

Construction of Cd(II) coordination polymers from a fluorene-based bisimidazole ligand and polycarboxylic acids: syntheses, structures and properties

Based on a fluorene-based bisimidazole ligand and polycarboxylic acids, six coordination polymers, namely [Cd2(bpdc)2(bief)2]∙xsolvent (1), [Cd(sdc)(bief)] (2), [Cd(odc)(bief)]∙H2O (3), [Cd2(1,4-ndc)2(bief)2]∙H2O (4), [Cd2(1,4-ndc)2(bief)2]∙3H2O (5) and [Cd(tdc)(bief)(H2O)] (6), have been synthesized and structurally characterized. Compound 1 exhibits a 2-fold interpenetrated sql net. Compound 2 and 3 present the 2D → 3D parallel polycatenation of sql net. Compound 4 features a 2D → 3D parallel polycatenation of binodal 4,6L56 net. Compound 5 exhibits an eight-connected tsi framework. Compound 6 exhibits an eight-connected bcu framework. Their thermal stabilities and photochemical properties have also been studied.

Structural diversity of six metal–organic frameworks from a rigid bisimidazole ligand and their adsorption of organic dyes

Six entangled coordination polymers from a bisimidazole ligand and versatile carboxylate acids have been synthesized and structurally characterized. Their adsorption behaviors to organic dyes have also been evaluated.

Three-pillared layer metal–organic frameworks assembled by imidazole-4,5-dicarboxylate and rigid bisimidazole ligands: synthesis, crystal structure, and sensing nitroaromatics

Three-pillared layer metal–organic frameworks based on 1H-imidazole-4,5-dicarboxylate and linear bis(imidazole) ligands generally formulated as {[Co3(idc)2(bib)3]·8H2O}n (1), {[Cd(Hidc)(bib)0.5]}n (2) and {[Cd(Hidc)(bibp)]}n (3), where H3idc = 1H-imidazole-4,5-dicarboxylate, bib = 1,4-bis(1-imidazolyl)benzene and bibp = 4,4′-bis(1-imidazolyl)biphenyl, have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 features a 3-D-pillared layer structure with 1-D channels, generated by honeycomb-like 2-D layer linked by bib ligands. Compound 2 consists of 2-D lumpy layers of [Cd4(Hidc)4], which are further connected by bridging ligands of bib to generate a pillared layer 3-D framework with 1-D channels. In 3, the 2-D corrugated honeycomb networks, structurally analogous to CFx, are pillared by bibp ligands to form a 3-D architecture with 1-D channels. Through selecting different metal ions and the length of pillared ligands, the pore sizes are adjusted in the three complexes. The potential of 2 and 3 for nitro explosive sensing is investigated through luminescence quenching experiments, which show that 3 can be applied as a fluorescent sensor for nitro compounds.

Structural diversity of three entangled metal-organic frameworks from a bisimidazole ligand and dicarboxylic acids with varied length

Based on a bisimidazole ligand and dicarboxylic acids with varied length, three entangled metal-organic frameworks have been synthesized and structurally characterized. Compound 1 shows a 4-fold interpenetration of dia net. Compound 2 presents an unusual 1D→3D polycatenane by the 4-fold interpenetration of 1D tubular net. Compound 3 exhibits a 3-fold interpenetration of pcu net. Their luminescent properties were also investigated.

Synthesis and structures of a series of d10 coordination compounds based on flexible bis(imidazole) ligand and dicarboxylates

ABSTRACTA series of new coordination compounds based on 1,6-bis(2-methyl-imidazole-yl)-hexane (bimh), namely [Zn(bimh)0.5(chda)]n (1), {[Cd(bimh)0.5(bda)]·H2O}n (2), [Cd(bimh)(oba)]n (3), [Zn(bimh)(oba)]n (4), [Cd(bimh)(ipa)]n (5), {[Zn(bimh)0.5(ipa)]·H2O}n (6), (bimh = 1,6-bis(2-methyl-imidazole-1-yl)hexane, H2chda = 1,4-cyclohexanedicarboxylic acid, H2bda = 2,2′-biphenyldicarboxylic acid, H2oba = 4,4′-oxybis(benzoic acid), and H2ipa = isophthalic acid) have been synthesized by solvothermal route and diffusion method and characterized by elemental analysis, IR spectroscopy, single-crystal X-ray diffraction technology. Compound 1 affords a two-dimensional (2D) wave-like framework with dinuclear paddle-wheel units, where the structures are further assembled via aromatic π–π stacking to generate a 3D network. Compound 2 exhibits a 1D ladder chain, which is further linked by hydrogen bonds to form a 2D architecture. Compounds 3 and 4 are isostructural, possessing a 2D layer network based on hydrogen bonds. Compound 5 displays a 2D wave-like layer structure. Compound 6 has a 1D line chain structure, which is packed into a 3D supermolecule network by two types of hydrogen bonds. Furthermore, the thermal stabilities and photoluminescent properties for compounds 1–6 were investigated.

Three-dimensional nickel(II) and cobalt(II) coordination polymers constructed from 2,5-dichloroterephthalic acid and bis(imidazole) ligands

Two ternary mixed-ligand coordination polymers (CPs), namely [Ni(L)2(DCTP)] n (1) and [Co(L)(DCTP)] n (2), have been hydrothermally synthesized by reacting different transition metal salts with 2,5-dichloroterephthalic acid (H2DCTP) and 4,4′-[bis(imidazol-1-ylmethylene)]biphenyl (L) as ligands. Both CPs 1 and 2 were characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction; CP 1 exhibits a non-interpenetrated six-connected α-Po (or pcu net) framework structure, with the point symbol {412·63}. CP 2 shows a fivefold-interpenetrating four-connected sqc6 topology with the point symbol {66}. The thermal stabilities, luminescence and catalytic properties of both CPs for the degradation of methyl orange in a Fenton-like process have been investigated.

A family of entangled coordination polymers constructed from a flexible bisimidazole ligand and versatile polycarboxylic acids: Syntheses, structures and properties

A family of entangled coordination polymers, namely, [Cd(cba)(ibpi)] (1), [Cd(sdc)(ibpi)]·H2O (2), [Cd2(bpdc)2(ibpi)2] (3), [Ni2(sdc)2(ibpi)2(H2O)2]·H2O (4), [Cd2(tdc)2(ibpi)]·H2O (5), [Cd(Hbtc)(ibpi)] (6), [Co2(tdc)2(ibpi)2·H2O]·2H2O (7) and [Cd2(cdc)2(ibpi)2]·2H2O (8). [ibpi=1-(4-(4-(1H-imidazol-1-yl)benzyloxy)phenyl)-1H-imidazole, H2cba=4,4′-carbonyldibenzoic acid, H2sdc=4,4′-sulfonyldibenzoic acid, H2bpdc=biphenyl-4,4′-dicarboxylic acid, H2cdc=1,4-cyclohexanedicarboxylic acid, H2tdc=thiophene-2,5-dicarboxyl acid, and H3btc=1,3,5-benzenetricarboxylic acid], have been synthesized and structurally characterized. Compound 1 exhibits a 2-fold parallel interpenetration of sql networks. Compound 2 presents a 3-fold parallel interpenetration of sql networks. Compound 3 features a parallel polycatenation of 3-fold interpenetrated sql networks. Compound 4 shows a unique type of inclined interpenetration of sql networks. Compound 5 displays a 3-fold interpenetration of pcu network. Compound 6 exhibits a uninodal self-catenating mab network. Compound 7 shows an 8-connected self-catenating framework of 8T10 topology with the point symbol (420·68). Compound 8 presents a unique 8-connected 8T21 self-catenating framework with the point symbol (424·64). The thermal stabilities and photochemical properties of compounds 1, 2, 3, 5, 6and8 have also been studied.