Dicarboxylate Ligands Research Articles

A new mixed-ligand Mn(II) coordination polymer: Protective and nursing values on renal calculus via reducing the Ca2+ concentration in urine

In the present study, via using the mixed-ligand synthesis approach, a new Mn(II)-containing coordination polymer (CP) with the chemical formula of {[Mn3(timb)2(SO3–IPA)2(H2O)2]·8H2O} n (1) has been successfully prepared via reaction of MnCl2·4H2O with the tripodal linker 1,3,5-tris(2-methylimidazole-1-yl)benzene (timb) and aromatic dicarboxylic acid ligand –SO3 group functionalized isophthalic acid (H2IPA) ligand. Furthermore, the biological activity of the new compound on renal calculus was assessed, and the related mechanism was explored as well. The Calcium Colorimetric Assay was conducted and the concentration of Ca2+ in urine was determined. The western blotting assay was conducted and the expression levels of the osteopontin (OPN) in the distal tubule were measured. Molecular docking simulation revealed that the carboxyl, iminazole, and sulfonate groups were all involving into the binding interactions with the target protein, and therefore exhibited strong biological activity.

Multi-thiol-supported dicarboxylate-based metal–organic framework with excellent performance for lithium-ion battery

With the reversible two-electron redox reaction, dicarboxylates have been widely employed as advanced anodes for lithium-ion batteries. However, dicarboxylate-based anodes always displayed limited capacities, low rate performances, and poor long-cycle abilities due to their inevitable dissolution in the electrolyte. Here, to address the above-motioned issues, a functional multi-thiol-supported dicarboxylate-based metal–organic framework, namely Fe-TTTP, is synthesized and employed as a promising anode for lithium-ion batteries based on the redox-active Iron (III) ions and organic dicarboxylate ligands. Benefiting from its chemical structure with multiple redox metal-centers, high theoretical specific capacity, and insolubility, Fe-TTTP gains superior electrochemical performances, including a high reversible (charge) capacity of 950 mAh g−1 at 50 mA g−1, excellent rate performance (95 mAh g−1 up to 10000 mA g−1, 1.1 min for each cycle), and extraordinary cycling stability (310 ± 20 mAh g−1 for 5000 cycles at 2000 mA g−1).

RETRACTED: Two new Mn(II) coordination polymers: Photocatalytic property and treatment activity on colorectal cancer by inhibiting cancer cell migration and invasion

Two new binary Mn(II) coordination polymers, namely [Mn(5-MeO-ip)(DMF)] n ( 1 ) and [Mn(obb)] n ( 2 ) (5-MeO-H 2 ip = 5-methoxyisophthalic acid, H 2 obb = 4,4′-oxydibenzoic acid), have been synthesized via the self-assemble reactions of Mn(II) ions with two different dicarboxylic acid ligands. The optical band gaps for 1 – 2 are 3.21 eV, 3.50 eV, respectively, and their photocatalytic properties for the degradation of MV under UV light irradiation were also investigated. For the colorectal cancer treatment, the biological activity was evaluated and the specific mechanism was explored at the same time. Firstly, the inhibitory activity of the new compounds on the colorectal cancer cell viability was measured with CCK-8 assay. Next, the real time RT-PCR was used to measure the activation of the VEGF signaling pathway in the colorectal cancer cells after compound treatment.

Construction of a new chiral hetermetallic Gd(III)–Cu(II)–camphorate: photocatalytic property and application values in the treatment of pancreatitis

Employing the dicarboxylate ligand of D-H2cam to react with Gd2O3 and Cu(NO3)2·3H2O under hydrothermal conditions, we successfully prepared a new heterometallic compound, namely [Gd2Cu(D-cam)4(H2O)]n (1, D-H2cam is d -(+)-camphoric acid). Moreover, the photocatalytic performance was also explored for the methylene blue (MB) solution degradation under the irradiation of ultraviolet light. Its application values on the pancreatitis treatment were examined and the corresponding mechanism was tested in meantime. Firstly, the cell counting kit-8 (CCK-8) assay was conducted and the compound’s inhibitory effect against the pancreatitis cells viability was detected. Besides, the detection of the inflammatory cytokines content released into plasma was performed enzyme-linked immunosorbent assay (ELISA) detection.

An X-ray Photoelectron Spectroscopy Study of Postsynthetic Exchange in UiO-66.

Postsynthetic exchange (PSE) is a method that is widely used to change the composition of metal-organic frameworks (MOFs) by replacing connecting linkers or metal nodes after the framework has been synthesized. However, few techniques can probe the nature and distribution of exchanged species following PSE. Herein, we show that X-ray photoelectron spectroscopy can be used to compare the relative concentrations of exchanged ligands at the surface and interior regions of MOF particles. Specifically, PSE of iodobenzene dicarboxylate ligands results in a gradient distribution from surface to bulk in UiO-66 nanoparticles that depends on PSE time. X-ray photoelectron spectroscopy also reveals differences between the surface chemistry of the PSE product and that of the direct synthesis product.

Pt(ii)-coordinated tricomponent self-assemblies of tetrapyridyl porphyrin and dicarboxylate ligands: are they 3D prisms or 2D bow-ties?

Thermodynamically favored simultaneous coordination of Pt(ii) corners with aza- and carboxylate ligands yields tricomponent coordination complexes with sophisticated structures and functions, which require careful structural characterization to paint accurate depiction of their structure–function relationships. Previous reports claimed that heteroleptic coordination of cis-(Et3P)2PtII with tetrapyridyl porphyrins (M′TPP, M′ = Zn or H2) and dicarboxylate ligands (XDC) yielded 3D tetragonal prisms containing two horizontal M′TPP faces and four vertical XDC pillars connected by eight Pt(ii) corners, even though such structures were not supported by their 1H NMR data. Through extensive X-ray crystallographic and NMR studies, herein, we demonstrate that self-assembly of cis-(Et3P)2PtII, M′TPP, and four different XDC linkers having varied lengths and rigidities actually yields bow-tie (⋈)-shaped 2D [{cis-(Et3P)2Pt}4(M′TPP) (XDC)2]4+ complexes featuring a M′TPP core and two parallel XDC linkers connected by four heteroleptic PtII corners instead of 3D prisms. This happened because (i) irrespective of their length (∼7–11 Å) and rigidity, the XDC linkers intramolecularly bridged two adjacent pyridyl-N atoms of a M′TPP core via PtII corners instead of connecting two cofacial M′TPP ligands and (ii) bow-tie complexes are entropically favored over prisms. The electron-rich ZnTPP core of a representative bow-tie complex selectively formed a charge-transfer complex with highly π-acidic 1,4,5,8,9,12-hexaazatriphenylene-2,3,6,7,10,11-heaxacarbonitrile but not with a π-donor such as pyrene. Thus, this work not only produced novel M′TPP-based bow-tie complexes and demonstrated their selective π-acid recognition capability, but also underscored the importance of proper structural characterization of supramolecular assemblies to ensure accurate depiction of their structure–property relationships.

Three novel MOFs constructed from 1,3,5-tris(1-imidazolyl)benzene and dicarboxylate ligands with selective adsorption for C2H2/C2H4 and C2H6/CH4.

The urothermal reactions of Co(II)/Zn(II) salts with the diverse carboxylic acid and 1,3,5,-tris(1-imidazolyl)benzene(tib) ligands afforded three novel MOFs, namely, [Co3(tib)2(abdc)2(ox)]2·6H2O (1), [Co3O(tib)(abdc)2(DMI)]·2DMI·2H2O (2) and [Zn3I2(tib)2(napdc)2]·2DMI·2H2O (3), (H2abdc = 5-amino-1,3-benzenedicarboxylate, H2napdc = 1,4-naphthalene dicarboxylic acid and DMI = 1,3-dimethyl-2-imidazolidinone). In compounds 1 and 2, the Co(II) atoms are connected by polycarboxylate ligands to form two-dimensional (2D) layers that are pillared by tib ligands leading to the formation of 3D porous frameworks. In compound 3, the Zn(II) atoms are linked by tib ligands to form one-dimensional ribbon-like chains which are further connected by polycarboxylate ligands, making a 3D framework possible. Compound 1 can selectively adsorb unsaturated hydrocarbon molecules (C2H2 and C2H4) and saturated hydrocarbon molecules (C2H6 and CH4). Specifically, compound 1 has high IAST selectivity for acetylene and methane (0.50 : 0.50, v/v) at 273 K and 1 bar. DFT calculations reveal that the π-conjugated hexagonal carbon ring may be the primary adsorption site because there are π-π interactions between the unsaturated hydrocarbon molecules (C2H2 and C2H4) and the π-conjugated hexagonal carbon ring in the framework of compound 1.

Distinct nonlinear optical responses in three pairs of 2D homochiral Ag(i) enantiomers modulated by dicarboxylic acid ligands

Based on three pairs of 2D homochiral Ag(i) enantiomers, we demonstrate that both the symmetry and degree of π-conjugation of the ligands have a significant effect on the type and intensity of their NLO responses.

Structural and spectroscopic studies of spontaneously formed crystalline Eu(iii)-aliphatic dicarboxylates at room temperature.

Complexation of actinides and lanthanides with carboxylic organic ligands is a critical issue affecting radionuclide migration from deep geological disposal systems of spent nuclear fuel. A series of Eu(iii)–aliphatic dicarboxylate compounds, as chemical analogs of radioactive Am(iii) species, Eu2(Ox)3(H2O)6, Eu2(Mal)3(H2O)6, and Eu2(Suc)3(H2O)2, were synthesized and characterized using X-ray crystallography and time-resolved laser fluorescence spectroscopy to examine the ligand-dependent binding modes and the corresponding changes in spectroscopic properties. Powder X-ray crystallography results confirmed that all of the compounds presented a crystalline polymer structure with a trigonal prism square-face tricapped polyhedron geometry centered on Eu(iii) in a nine-coordinate environment involving nine oxygen atoms. This study captures the transition of the coordination modes of aliphatic dicarboxylate ligands from side-on to end-on binding as the carbon chain length increases. This transition is illustrated in malonate bindings involving a combination of side-on and end-on modes. Strongly enhanced luminescence, especially for the hypersensitive peak, indicates a low site symmetry in the formation of solid compounds. The number of remaining bound water molecules was estimated from the resultant increased luminescence lifetimes, which were in good agreement with crystal structures. The excitation–emission matrix spectra of these crystalline polymers suggest that Ox ligands promote the sensitized luminescence of Eu(iii), especially in the UV region. In the case of Mal and Suc ligands, charge transfer occurs in the opposite direction from Eu(iii) to the ligands under UV excitation, resulting in weaker luminescence.

Homochiral imidazolium-based dicarboxylate silver(i) compounds: synthesis, characterisation and antimicrobial properties

Ag(i) complexes derived from chiral imidazolium-based dicarboxylate ligands have shown good antimicrobial activity toward Gram-negative bacteria. A chirality-antimicrobial tendency has been revealed.

Synthesis, crystal structure, and luminescent property of a new heterometallic compound based on a large π-conjugated dicarboxylate ligand

Presented here is a new heterometallic compound with the formula of [CdCa(L)2(H2O)(DMF)]n (1, H2L = 5-(1-oxoisoindolin-2-yl)isophthalic acid, DMF = N,N’-dimethylformamide), which was synthesized under solvothermal conditions. Compound 1 crystallized in the orthorhombic Pna21 space group, and the unit cell parameters of 1 are a = 18.3689(11) Å, b = 14.2830(11) Å, c = 13.9233(11) Å, and α = 90°, β = 90°, γ = 90°, Z = 4. The heterometallic dinuclear [CdCa(COO)3] building subunits are connected by the L2- ligands into a 3D framework. Topological simplification for 1 represents a binodal (3,5)-connected topological network. The result of luminescence test revealed that compound 1 may be good candidate of blue luminescent material.

Plumbing the uncertainties of solvothermal synthesis involving uranyl ion carboxylate complexes

Uranyl ion complexes with long-chain, saturated or unsaturated aliphatic dicarboxylate ligands illustrate how solvo-hydrothermal synthetic conditions sometimes result in the formation of species different from those hoped for.

Zn(ii) and Co(ii) coordination polymers based on semi-rigid bis-pyridyl-bis-amide and angular dicarboxylate ligands: synthesis, structures and properties

Hydro(solvo)thermal reactions ofN,N′-di(3-methylpyridyl)oxalamide (L1) andN,N′-di(4-methylpyridyl)oxalamide (L2) with angular dicarboxylic acids and metal salts afforded six new coordination polymers showing interesting properties.

RETRACTED: Treatment activity of 0D/2D coordination complexes on gastric carcinoma by inhibiting the cancer cell viability

In the present study, via reaction of Ni(NO 3 ) 2 ·6H 2 O with two flexible dicarboxylic ligands under the solvothermal reaction conditions, two new Ni(II)-containing coordination complexes with the chemical formulae of [Ni4(L1) 4 (DMF) 4 ·2DMF] n ( 1 ) and [Ni(L2)(DMF)] n ( 2 ) (H2L1= 2,2'-(1,4-phenylenebis(methylene))bis(sulfanediyl)dinicotinic acid and H2L2 ​= ​2,2'-(1,2-phenylenebis(methylene))bis(sulfanediyl)dinicotinic acid) have been prepared. For the treatment of the gastric carcinoma, the Cell Counting Kit-8 kit was carried out for the detection of the gastric carcinoma cells viability after compound treatment. Additionally, the Annexin V-FITC/PI apoptosis assay was also conducted and the apoptosis levels of the gastric carcinoma cells were determined after compound exposure.

Structural Rationale towards Designing Coordination Polymer Based Metallogels Displaying Anti‐Cancer and Anti‐Bacterial Properties

AbstractA new series of organic‐inorganic‐hybrid‐systems (OIHS) was synthesized with the aim of developing metallogels that might display ‘drug‐like’ function. Reaction of two dicarboxylate ligands namely 3‐carboxycinnamic acid (3‐cca) and 4‐carboxycinnamic acid (4‐cca) with various bivalent metal ions (Cu(II), Zn(II), Co(II), Cd(II), Mn(II)) produced a new series of OIHS which were crystallographically characterized; five of which were coordination polymers (CP1‐CP5) and one metal‐organic polyhedra (MOP‐1). Reaction of 3‐cca with various metal ions in presence of DMSO/water produced five metallogels (MG1‐MG5) of which the Zn(II)‐metallogel namely MG1 was evaluated for both anti‐cancer and anti‐bacterial properties against murine tumor cell line B16‐F10 (human skin cancer model) and gram positive bacterium S. aureus. While MTT and cell migration assays established the anti‐cancer activity of MG1 against B16‐F10, flow cytometry and laser scanning confocal microscopy (LSCM) images under various staining conditions supported apoptotic pathway of cancer cell death. Anti‐bacterial ability of MG1 was also established against S. aureus by zone inhibition, and flow cytometry and LSCM studies under various staining conditions. MG1 was also demonstrated to be effective in killing the intracellular bacterial cells when B16‐F10 cells were infected with S. aureus thereby suggesting its potential in treating post‐operative cancer surgery model system.

Syntheses, crystal structures and properties of three compounds based on the dicarboxylate ligand with S-S flexible linkage

Three new compounds, [MnL(2, 2΄-bipy)2]n·1.5nH2O (1), Co(4, 4ˊ-bipy)(H2O)4·2HL (2) and 2HL·(4, 4ˊ-bipyH)·2H2O (3) (H2L = 2,2΄-dithiosalicylic acid, 2, 2΄-bipy = 2, 2΄-bipyridine, 4, 4΄-bipy = 4, 4΄-bipyridine), have been synthesized by hydrothermal and evaporation methods. Structural determination reveals that compound 1 shows a one-dimensional chain structure with L2- ligands adopting bridging coordination modes, compound 2 features a mononuclear structure with uncoordinated HL- anions, balancing the charges, compound 3 is a new inclusion compound of HL- anions and 4, 4ˊ-bipyH cation with π-π stacking interactions. In compounds 1-3, the flexible S-S linkages can make H2L ligands present different conformations of dihedral angles between the terminal benzene rings. The S-O hypervalent bonds can stabilize the conformations. Thermogravimetric analyses and fluorescent measurements of compounds 1 and 2 have been performed. Compounds 1 and 2 exhibit broad blue fluorescent emission bands at 420 nm and 424 nm, respectively.

Effect of the Defect Modulator and Ligand Length of Metal-Organic Frameworks on Carbon Dioxide Photoreduction.

The nature of defects and organic ligands can fine-tune the absorption energy (Eabs) of metal-organic frameworks (MOFs), which is crucial for photocatalytic reactions; however, the relevant studies are in their infancy. Herein, a series of typical MOFs of the UiO family (UiO-6x-NH2, x = 8, 7, and 6) with ligands of varied lengths and amino-group-modified defects were synthesized and employed to explore their performance for photocatalytic CO2 reduction. Sample UiO-66-NH2-2ABA (2ABA = 3,5-diamino-benzoate) with the shortest dicarboxylate ligand and two amino-group-modified defects exhibits superior photocatalytic activity due to the lowest Eabs. The CO yield photocatalyzed by UiO-66-NH2-2ABA is 17.5 μmol g-1 h-1, which is 2.4 times that of UiO-68-NH2-BA (BA = benzoate) with the longest ligand and no amino group involved in the defects. Both the experiments and theoretical calculations show that shorter dicarboxylate ligands and more amino groups result in smaller Eabs, which is favorable for photocatalytic reactions. This study provides new insights into boosting the photocatalytic efficiency by modulating the defects and ligands in MOFs.

Water-assisted proton conduction in a highly stable 3D lead(II) MOF constructed by imidazole dicarboxylate and oxalate ligands

Compared with the proton-conducting metal-organic frameworks (MOFs) constructed by transition metals and rare earth metals, there are fewer main group metal-based MOFs with proton-conducting ability. From the point of view of basic research, it is extremely important to prepare more main group metal-based MOFs to explore their proton conductivity and mechanism. Herein, a new highly stable three-dimensional Pb(II) MOF, [Pb2(p-IPhH2IDC)2(C2O4)]n (1) (p-IPhH3IDC ​= ​p-N-imidazole-1-yl)-phenyl-1H-imidazole-4,5-dicarboxylic acid) constructed by imidazole dicarboxylate and oxalate ligands was solvothermally prepared, which can hold its structural rigid after soaking in water or acidic and basic solutions. Its water-assisted proton conductivity was examined under different relative humidities and variable temperatures, and boosted with increasing temperature and humidity. In terms of crystal structural analysis, calculated activation energy (Ea) value, H2O vapor absorption and powder X-ray diffraction (PXRD) determinations, the proton conducting mechanism of 1 was speculated as well.

A novel 3D Pb(II) coordination polymer from a flexible dicarboxylate ligand which reversibly absorbs water

The dicarboxylic flexible ligand 4-((2-carboxyethyl)amino)benzoic acid (LH3) has been synthesized and its reaction with Pb(NO3)2 lead to the formation of a 3D coordination polymer formulated as {[Pb(LH)(H2O)]⋅H2O}n (1) which presents a very interesting structure with an sra underlying topology. Thermal stability studies combined with X-ray powder diffraction suggest that the molecular material displays soft crystalline properties; upon heating it loses its water content changing its structure, while upon rehydration under a variety of conditions the original structure is obtained.

Two Cd-MOFs with different types of channels based on phenylimidazole dicarboxylic acids: Synthesis, crystal structure and solid fluorescence properties

The reaction of cadmium(II) nitrate with two phenylimidazole dicarboxylic acids, 2-phenyl-1H-imidazole-4,5-dicarboxylic acid (H3PhIDC) and 2-p-methoxyphenyl-1H-imidazole-4,5-dicarboxylic acid (p-H3MOPhIDC), produce two new cadmium(II) organic frameworks (Cd-MOFs), namely [Cd4(HPhIDC)4(CH3CN)(H2O)]n (1) and {[Cd2(p-HMOPhIDC)2(H2O)2]•DMF}n (2). Structural analyses show that although 1 and 2 are both three-dimensional (3-D) network skeletons formed by the connection of phenylimidazole dicarboxylic acid, their channel types and porosity (8.8% for 1, 25.1% for 2) are different. The channel of 1 is a quadrilateral channel containing six Cd(II) ions, whereas the channel of 2 is a double channel containing ten Cd(II) ions in a staggered arrangement of large and small quadrilaterals. The difference in the structure and size of the channels of Cd-MOFs may be attributed to the bridging mode of the phenylimidazole dicarboxylic acid ligands. In addition, the fluorescence properties of 1 and 2 at room temperature in solid state were also studied.