V-shaped Ligand Research Articles

A mixed polynuclear clusters-based Y-MOF with an unprecedented (12, 12, 18)-c topology: highly efficient propylene/ethylene separation and iodine adsorption

The design and synthesis of highly stable metal–organic frameworks (MOFs) bearing unpredictable polynuclear clusters and new topologies are important for the development of novel and complicated MOFs. Herein, the polynuclear rare-earth (RE) clusters with more coordination modes and the small V-shaped ligand (2,5-thiophenedicarboxylic acid) were chosen, and subsequently JLU-MOF132 with three different yttrium clusters (two independent Y6 and one Y9 clusters) and a novel (12, 12, 18)-connected topology was successfully synthesized. Notably, JLU-MOF132 exhibits high porosity, excellent thermal, acid-base, and solvent stabilities. JLU-MOF132 shows considerable potential in methanol-to-olefins (MTO) products (C3H6 and C2H4) separation. The high ideal adsorbed solution theory C3H6/C2H4 selectivities (9.2, 10.6, and 15.1) and the breakthrough experiments results, including the high C2H4 purity (>99.9 %) and productivities (26.1, 73.1, and 101.0 L·kg-1), demonstrate its practical purification capability. Semi-empirical tight binding (xTB) quantum chemical calculations explain the mechanisms that differentiate C2H4 and C3H6 adsorption in JLU-MOF132. In addition, JLU-MOF132 also displays outstanding radioactive iodine adsorption performance, with an iodine uptake of 750 mg·g-1 in vapor and 153 mg·g-1 in cyclohexane solutions. Briefly, this work not only demonstrates the viability of employing the V-shaped ligand to increase the structural diversity of highly stable MOFs, but also enhances the application potential of MOFs in the fields of the MTO products separation and radioactive iodine adsorption.

Phenoxazine-based supramolecular metal-organic cage for picric acid detection

A phenoxazine-based metal-organic cage Zn2L3 (L = N-n-butyl-3, 7-dipyridine phenoxazine) was synthesized by the coordination-driven self-assembly, which could work as a fluorescent sensor for sensitive and selective detection of picric acid (PA) among nitro-explosives. The cage contains three V-shaped ligands L linked by zinc ions, and the fluorescence of the ligands is preserved and transferred to the cage. Different from the free phenoxazine-based ligand, Zn2L3 showed strong emission at 568 nm and exhibited the highest fluorescence quenching efficiency toward picric acid over other related nitroaromatic explosives. The cage structure with cavities exhibits the better sensing property than monomeric ligand. Electrospray ionization mass spectrometry (ESI-MS), NMR and fluorescence titration suggested that the formation of host–guest complex of the cage with the picric acid target, should be thought as the key factor for its nice recognition ability.

Two-Dimensional Mixed-Ligand Metal–Organic Framework Constructed from Bridging Bidentate V-Shaped Ligands

A two-dimensional and bifunctional pillar-layered metal–organic framework (MOF)—with the molecular formula [Zn(cba)(bpdb)]·DMF (2DTMU-1), H2cba = 4,4′-methylenedibenzoic acid, bpdb = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene—was obtained via the reaction of zinc(II) nitrate with H2cba as the carboxylate linker and bpdb as the N-donor pillar. 2DTMU-1 is based on a binuclear paddlewheel Zn(II) unit complexed by four bridging bidentate (dicarboxylate) V-shaped ligands, which combine to from H2cba; this tetragonal array, which is connected by bpdb with a bridging azine group, presents a pore size of 18 × 12 Å2.

Synthesis, structure and dielectric behavior study of Mn (II)-4,4′-sulfonyldibenzoate-auxiliary ligand system based coordination polymers (CPs)

Based on MnCl2.4H2O, V-shaped ligand 4,4′-sulfonyldibenzoic acid (H2SBA), and two N-containing auxiliary ligands three new coordination polymers (CPs), namely: [Mn3(SBA)2(pyzc)2(DMA)2].DMA.H2O 1, [Mn3(SBA)2(phen)2(OAc)2].2DMA 2, and [Mn3(SBA)2(phen)2(OAc)2].2EtOH 3 [where, SBA = 4,4′-sulfonyldibenzoate, pyzc = 2-pyrazinecarboxylate, phen = 1,10-phenanthroline, OAc = acetate, DMF = N, N'-dimethylformamide, DMA = N, N'-dimethylacetamide] were synthesized using mixture of polar protic/aprotic solvents under solvothermal conditions. Single crystal X-ray study revealed that solid 1 is composed of tetrameric {Mn4O20N2} and dimeric units {Mn2O8N2}, whereas solids 2 and 3 are built of trimeric cluster {Mn3N2O14}. The structurally similar 2D coordination solids 2 and 3 showed comparable dielectric constant (ɛ'∼15.0) at room temperature. Solid 1 exhibited a higher value of dielectric constant (ɛ'∼30.5) probably due to the contribution from disordered polar guest solvent molecules, and 1D manganese carboxylate chains interaction. The crystal engineering of soluble 1:1 manganese carboxylate complex species, with or without coordination with an auxiliary ligand, is also explained mechanistically in this study. The approach not only provides a rationale for the composition and variation in the coordination linkage but also describes the crystal packing in terms of the dominant directional coordination and H-bonding forces.

Pore-Directed Solid-State Selective Photoinduced E – Z Isomerization and Dimerization within Metal–Organic Frameworks

Pore-Directed Solid-State Selective Photoinduced <i>E</i> – <i>Z</i> Isomerization and Dimerization within Metal–Organic Frameworks

A 'two-in-one' crystal having two different dimensionality in the extended structures: A series of cadmium(II) coordination polymers from V-shaped organic linkers

Three Cd(II) containing coordination polymers, formulated as {Cd(oba)(biip)}n·nH2O (1), {Cd(sdba)(biip)}n·n5H2O (2) and {[Cd1.5(hfipbb)2(biip)1.5(H2O)][Cd(hfipbb)(biip)]}n·n2H2O (3), have been synthesized by using ditopic V-shaped ligands i.e., H2oba (4,4′-oxydibenzoic acid), H2sdba (4,4ʹ-thiodibenzoic acid), H2hfipbb {4,4ʹ-(perfluoropropane-2,2-diyl)dibenzoic acid} and an auxiliary linker, biip {3,5-di(1H-imidazol-1-yl)pyridine} under solvothermal conditions. Compounds 1–3 are characterized by single crystal X-ray diffraction analysis, IR spectroscopy, thermogravimetric (TG) and elemental analyses. Compound 1 contains a 3D framework, formed by the connectivity of {CdO4N2} secondary building unit (SBU) with the organic linkers, whereas compound 2 is a 2D coordination polymer. Interestingly, unlike to compounds 1 and 2, compound 3 possesses a distinctive structural feature having two crystallographically independent polymeric motifs (polymers, A and B) having two different dimensionality within the same crystal, i.e., coordination polymer A (CP-A) that forms a one-dimensional motif and coordination polymer B (CP-B), which has a two-dimensional structure.

Structural Regulation and Light Hydrocarbon Adsorption/Separation of Three Zirconium-Organic Frameworks Based on Different V-Shaped Ligands.

On the basis of different V-shaped ligands, three zirconium-organic frameworks (JLU-Liu45, Zr-SDBA, and Zr-OBBA) have been successfully constructed. By regulating spatial configuration and functional groups of organic ligands, these as-synthesized Zr-MOFs (MOF = metal-organic framework) display distinct structures and different light hydrocarbon adsorption/separation capabilities. JLU-Liu45, with a double-walled interpenetrated 3D primitive cubic (pcu) framework, exhibits good gas-adsorption capacity but not prominent selective separation ability. Through regulating sizes and torsion angles of the organic ligands, Zr-SDBA possesses a 2D square lattice (sql) network, while Zr-OBBA displays a non-interpenetrated 3D pcu framework. Furthermore, by regulating functional groups on the ligands, Zr-SDBA shows prominent C2H2 uptake (101.2 cm3·g-1) and the best C2H2/CH4 selectivity (230.5, 1:1) among the three Zr-MOFs, and Zr-OBBA shows a significant C3H8/CH4 selectivity (105.6, 1:1). This work demonstrates the feasibility of structural regulation for MOF materials in the light hydrocarbon adsorption/separation field.

A Stable Cd(II)-Based Metal-Organic Framework: Synthesis, Structure, and Its Eu3+ Functionalization for Ratiometric Sensing on the Biomarker 2-(2-Methoxyethoxy) Acetic Acid.

A novel two-dimensional Cd-based metal-organic framework (MOF), [Cd(pddb)H2O]n (Cd-MOF), has been hydrothermally synthesized using the V-shaped ligand 4,4'-(pyridine-2,6-diyl)-dibenzoic acid (H2pddb) and structurally characterized. The framework exhibits fascinating one-dimensional in-plane channels functionalized with active pyridine-N sites. The as-synthesized Cd-MOF exhibits excellent water and chemical stability. Furthermore, a simple and nondestructive coordinated postsynthetic modification method has been applied to Cd-MOF to obtain a class of MOF hybrids functionalized by lanthanide ions. More interestingly, Eu3+@Cd-MOF can act as a dual-emissive ratiometric fluorescent probe for 2-(2-methoxyethoxy) acetic acid (MEAA), a metabolite of 2-(2-methoxyethoxy) ethanol, which could result in DNA damage and teratogenic and developmental toxicity. During the sensing process, the fluorescence sensor exhibits notable water tolerance, reusability, and a low detection limit (8.5 μg mL-1). In addition, the chemical substances in human urine and serum do not interfere with the fluorescence quenching process, which makes it possible for the fluorescent probe to be applied in the detection of MEAA in human urine and serum systems. The possible sensing mechanism is also studied and discussed in detail.

Substituent-Mediated Transformation of Polynuclear Gold(I)-Sulfido Complexes—From Pentanuclear to Octadecanuclear Cluster-to-Cluster Transformation

Substituent-Mediated Transformation of Polynuclear Gold(I)-Sulfido Complexes—From Pentanuclear to Octadecanuclear Cluster-to-Cluster Transformation

Synthesis, crystal structures, dielectric and magnetic properties of manganese sulfonyldibenzoates

Six coordination polymers based on Mn(ii) and V-shaped ligand were successfully isolated and their dielectric as well as magnetic behaviours were investigated. The paper also discusses the growth of solids in terms of supramolecular aggregation.

Wo interpenetrating cobalt coordination polymers constructed by dicarboxylate and V-shaped N-donor ligands

Two novel cobalt coordination polymers {[L1Co(ipa)]·0.25(DMF)}n (1) and {[L2Co(cis-1,3-chdc)]·3(H2O)}n (2) (L1 = bis(4-(1H-benzo[d]imidazol-1-yl)phenyl)methanone, L2 = bis(4-(1H-imidazol-1-yl)phenyl)methanone, H2ipa = isophthalic acid, H2(cis-1,3-chdc) = cis-1,3-cyclohexanedicarboxylic acid) are prepared under solvothermal conditions. These complexes are characterized by elemental analyses, IR spectroscopy, and X-ray crystallography. Complex 1 presents a 4-fold 3D network with a diamond net, while complex 2 shows a 2-fold 2D network with a square-grid net.

Synthesis, structural characterization, antibiotics sensing and coordination chemistry of a fluorescent 4-amino-1,8-naphthalimide Tröger’s base supramolecular scaffold

ABSTRACT The solvothermal synthesis and structural characterization of two new supramolecular coordination polymers featuring a unique V-shaped ligand bis-[N-(3-pyridyl)methyl)]-9,18-methano-1,8-naphthalimide-[b,f][1,5]diazocine (TBNap), are reported. The ligand TBNap was synthesized as a racemic mixture and the molecular structure was analyzed crystallographically. TBNap showed a positive solvatochromism effect which was further supported by DFT calculations illustrating the D-π-A type fluorophore effects within the ligand structures. TBNap was further employed as a potential fluorescence probe for the discriminative sensing of structurally assorted antibiotics. A strong fluorescence quenching and preferential binding affinity were realized for nitro-containing antibiotics, i.e., Furazolidone, Nitrofurantoin and Nitrofurazone. The solvothermal reaction of TBNap with Cd(OAc)2‧2H2O afforded a one-dimensional coordination polymer (TB-CP-1, poly-[Cd(TBNap)(OAc)2]). Similarly, reaction between TBNap and CdCl2.4H2O in DMF-C2H5OH rendered a 4,4’-2D coordination sheet (TB-CP-2, poly-[CdCl2(TBNap)]·DMF). The extended polymeric structures are further propagated into 3D supramolecular network through multiple face-to-face π-π interaction.

Synthesis of a Cobalt Coordination Polymer Based on 4-(1H-Imidazol-1-yl)phenyl)methanone and Fumaric Acid

A cobalt coordination polymer with V-shaped ligands, {[Co0.5(L1) ⋅ (C4H2O4)0.5] ⋅ 0.25H2O}n, (L1 = 4-(1H-imidazol-1-yl)phenyl)methanone, C4H2O4 = fumarate) has been synthesized under the solvothermal conditions. It has been characterized by elemental analysis, FT-IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is crystallized in the monoclinic space group C2/m with the unit cell parameters a = 10.6921(6) A, b = 20.7735(10) A, c = 8.8688(5) A, and β = 107.615(6)°, Z = 4. X-ray crystal analysis reveals that the 1D [Co(L1)4] chains are linked by two adjacent fumarate ligands to form a 2D framework.

Synthesis and Crystal Structure of a Zinc Coordination Polymer Based on Bis(4-(2'-methylimidazol)phenyl)sulfone and (1,1'-Biphenyl)-2,2'-dicarboxylate Ligands

Zinc coordination polymer with V-shaped ligands, {[Zn(L1) ⋅ (bpda)] ⋅ H2O}n, (1) (L1 = bis(4-(2'-methylimidazol)phenyl)sulfone, H2bpda = (1,1'-biphenyl)-2,2'-dicarboxylic acid) was synthesized under solvothermal condition. The structure of 1 was determined by single-crystal X-ray diffraction analysis and further characterized by infrared spectra and elemental analyses. In 1, the Zn(II) ion is four-coordinated by two nitrogen atoms of two distinct L1 ligands and two oxygen atoms of two bpda2– to form a distorted tetrahedron. Complex 1 displays a 2D four-connected framework with a (65 × 8) topology along c direction.

A Zn(II)-MOF with Suitable Pore Surroundings for Cyanosilylation Reaction and Protective Effect on Bladder Cancer Cells by Regulating miR-130 and CYLD

A porous metal–organic framework (MOF) based on Zn(II) metal nodes was prepared via reaction of rigid V-shaped ligand 2,6-di(2′,5′-dicarboxylphenyl)pyridine (H4L) along with Zn(NO3)2·6H2O in water and DMF mixed solvent, and its chemical formula was [Zn3(L)(OH)2(H2O)4](DMF)5 (1). The results show that the obtained activated 1a has catalytic activity for aromatic aldehydes cyanation under the existence of the trimethylsilyl cyanide, thus providing trimethylsilyl cyanohydrin in the form of shape along with size selection. In addition, a feasible synergistic mechanism of 1a for cyanosilylation of aldehyde also has been put forward. Furthermore, the treatment function of the compound on bladder cancer cells was assessed. The reverse transcription-polymerase chain reaction (PT-PCR) was carried out to determine cyclindromatosis (CYLD) and miR-130 relative expression in bladder cancer cells after the combine therapy. Besides, the mechanism of the compound was explored, by evaluating the level of autophagic programed cell death by western blot.

A new ZnII metallocryptand with unprecedented diflexure helix induced by V-shaped diimidazole building blocks.

Taking advantage of V-shaped ligands, a ZnII metallocryptand, namely {[Zn2(didp)2(m-bdc)2]}n, (1) [didp = 2,8-di(1H-imidazol-1-yl)-dibenzothiophene and m-H2bdc = isophthalic acid], has been hydrothermally synthesized. Single-crystal X-ray diffraction analysis reveals a 26-membered butterfly-type metallomacrocycle [Zn2(didp)2]. One m-bdc2- ligand bridges [Zn2(didp)2] units to form a laterally non-symmetric [Zn2(didp)2(m-bdc)] metallocryptand with an exo-exo conformation. Another crystallographically independent m-bdc2- functions as a secondary synthon to bridge discrete metallocryptands into a 1D zigzag chain architecture. Undoubtedly, the choice of two matched ligands in this work is crucial for metallocryptand construction and structure expansion. Interestingly, a rare helical chain with two flexures in one single L and/or R strand is observed. Another important feature is the C-O...π interactions, by which the dimensionality extension of (1) can be induced. Fluorescence measurements and density functional theory (DFT) calculations illustrate that the emission of (1) can probably be attributed to ligand-to-ligand charge transfer (LLCT).

Synthesis and Crystal Structure of a Cobalt Coordination Polymer Based on Bis(4-(1H-imidazol-1-YL)phenyl)methanone and trans-1,2-Cyclohexanedicarboxylate

A cobalt coordination polymer with V-shaped ligands, {[L1Co(trans-CHDCA)] · 2H2O}n (L1 = bis(4-(1H-imidazol-1-yl)phenyl)methanone, trans-H2CHDCA = trans-1,2-cyclohexanedicarboxylic acid) has been synthesized under solvothermal conditions. It has been characterized by IR spectra, elemental analyses and single-crystal X-ray diffraction. The crystal is monoclinic, sp. gr. P21/c, Z = 4. In crystal, trans-CHDCA2– ions bridge Co atoms into wave-like chain along the c-axis. Furthermore, chains are linked by bis(4-(1H-imidazol-1-yl)phenyl)methanone to form 2D layers.

Structure and Magnetic Property of A pcu Cobalt(II) Network Constructed with Mixed-Clusters and V-shaped Ketone Ligand

The V-shaped ketone ligand, benzophenone-2,4′-dicarboxylic acid (H2bpdc), was used as a long ditopic asymmetric linker to bridge mixed cobalt(II) clusters into a three-dimensional pcu network, namely [Co7(μ3–OH)2(bpdc)6(2,2′-bpy)4]·2H2O (1) (2,2′-bpy=2,2′-bipyridine), which was synthesized by methods of hydrothermal reaction and the crystal structure was determined. The linear trinuclear cluster [Co3(COO)6] and planar tetranuclear cluster [Co4(μ3–OH)2(COO)4] simultaneously appeared in the same compound for the first time. IR, elemental analysis and XRPD confirmed the phase purity of the bulk materials. Magnetic properties of 1 in the 300–2 K have been studied, which reveal the occurrence of antiferromagnetic interactions between Co(II) ions.

CAU-11-COOH with a V-Shaped Linker as a Catalyst for the Solvent-Free Synthesis of Cyclic Carbonates from CO₂ and Epoxides.

An Al3+-based metal-organic framework (MOF), CAU-11-COOH, with a V-shaped ligand, DPSDA (3,3'-4,4'-diphenylsulfonetetracarboxylic dianhydride), was prepared using the solvothermal method, and was characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, elemental analysis, thermogravimetric analysis, Brunauer-Emmett-Teller analysis, and CO₂ adsorption. The catalytic efficiency of CAU-11-COOH was investigated in the solvent-free cycloaddition of carbon dioxide with epoxides, which yielded five-membered cyclic carbonates under mild reaction conditions. CAU-11-COOH with a co-catalyst, tetrabutylammonium bromide (TBAB), gave higher than 98% yield of epichlorohydrin carbonate at 80 °C without a solvent. A plausible reaction mechanism in which the Lewis acidic metal center, an uncoordinated carboxyl group, and a nucleophilic bromide anion operate synergistically is proposed. The CAU-11-COOH catalysts were found to exhibit high thermal stability and could be reused more than four times without any significant reduction in activity.

Mixed-ligand coordination polymers: structural diversity and protective effect on cardiac arrest induced by anesthesia via inducing Sirt1 pathway

A reaction of the N-donor ligand 1,3-di(1H-imidazol-1-yl)benzene (dimb) with Co(NO3)2·6H2O and the V-shaped carboxylate ligand biphenyl-3,4',5-tricarboxylic acid (H3bpt) under hydro- or solvothermal conditions yields two new Co(II)-based coordination polymers with the chemical formulas {Co3(dimb)2(bpt)2(H2O)4]}n (1) and [Co2(dimb)2(Hbpt)2]·H2O (2). Furthermore, the treatment effect of compounds 1 and 2 against cardiac arrest induced by anesthesia is evaluated. Firstly, ELISA is used to detect the content of cardiac troponin T and B brain natriuretic peptide after treatment with the compounds. Moreover, RT-PCR is conducted and the relative expression level of Sirt1 in the rat myocardial tissue is measured.