Carboxylic Acid Ligands Research Articles

A Photostable 1D Ruthenium−Zinc Coordination Polymer as a Multimetallic Building Block for Light Harvesting Systems

AbstractA luminescent ruthenium complex bearing two 2,6‐di(quinolin‐8‐yl)‐pyridine carboxylic acid (dqpCOOH) ligands has been successfully synthesised and fully characterised. The new metalloligand has been coordinated to zinc ions through the terminal carboxylate groups using a one‐step solvothermal method, to give a multimetallic photoactive 1D coordination polymer, Ru−(dqpCOO)−Zn−(OOCH)2. Through use of X‐ray crystallography, advanced microscopy techniques as well as photophysical studies, we have extensively characterised the coordination polymer. The optical properties of the ruthenium complex and corresponding coordination polymer show that the material experiences a dramatic increase in photostability compared to the free parent metalloligand, in solution. Electrochemical measurements of the coordination polymer also confirm the RuII/RuIII redox couple is maintained in the polymeric network. The development of this material gives a new strategy in the design of novel photoactive materials as multimetallic building blocks for their use in light‐based applications.

Solvent induced synthesis of uranium organic frameworks: From 1D→2D based on a flexible carboxylic acid ligand

The development of nuclear energy gives lots of spent fuel which do harm to the environment and human health. There are numerous researchers focused on the disposal of the spent fuel with the adsorption method by selecting different materials as adsorbents. This work aims to handle the waste by using Lewis acid to accumulate and solidify the uranium. In this study, to remove the uranium from the spent fuel, a novel flexible tripod carboxylic acid based on sulfur was used to react with the uranium to form the interesting uranium organic framework with a one-dimensional chain and two-dimensional network. To our knowledge, this is the first case of the MOFs (Metal-Organic Frameworks) based on the ligand H3TTTTA, and the ligand in the compounds gives different coordination styles. All the UOFs exhibit outstanding stability in the solution with pH from 1 to 14, which shows brilliant application potential in the extreme environment. The methyl violet was selected to verify the adsorption properties of the materials, and UOF-1 shows the best removal rate of 96.98% in 24 h.

Syntheses, structures, magnetic and fluorescence properties of coordination polymers constructed with the reduced Schiff base carboxylic acid ligand

Using a reduced Schiff base carboxylic acid ligand 2-((pyridin-4-ylmethyl)amino)terephthalic acid (H2L), five new coordination polymers (CPs), namely, {[Mn2(L)2(H2O)]·DMF]}n (1), {[Cd(L)(H2O)2]}n (2), {[Cu(L)(H2O)3]·2H2O}n (3), {[Cu(L)(H2O)]}n (4), {[Eu2(L)3(H2O)3(H2O)0.5]·O}n (5) were obtained via different synthesis method and further characterized. Complex 1 is a three-dimensional (3D) framework with a (3, 8)-connected hex topology constructed by binuclear [Mn2N2O9] building unit. In complex 2, the adjacent Cd(II) centers are connected by L2‒ ligands using (κ2)-(κ2)-(κ1)-μ3 coordination pattern to form two-dimensional plane structure. In complex 3, the one-dimensional structures linked by hydrogen bonds (O4‒H7B···O7) to form a 2D supramolecular structure. 4 is a 3D structure and 5 belongs to (3, 5)-connected topology with point symbol of {48·62}. It is worth noting that complexes 1, 3 and 4 show the significant antiferromagnetic interactions indicated that they are potential magnetic materials. Remarkably, compared with H2L ligand, the maximum emission peaks of 2 exhibit varying degrees of blue-shifted, and further study for 2 finds that it can acts as luminescence sensor to selectively detect nitrobenzene (NB).

Metal-Ion Coupling in Metal-Organic Framework Materials Regulating the Output Performance of a Triboelectric Nanogenerator.

Metal-organic frameworks (MOFs) as friction nanopower generation materials have attracted more and more research and attention because of the inherent three-dimensional framework structure and large aperture. In this work, the ZUT-75(Mn) with a one-dimensional pore structure was synthesized by using electron-rich benzimidazole carboxylic acid ligands, and isomorphic offspring MOF materials were obtained by single crystal-single crystal solvent-assisted metal-ion exchange. The exchange process was monitored by liquid UV-vis spectroscopy, atomic absorption spectrometry, and energy-dispersive X-ray spectroscopy. The metal-oxygen coordination energy, X-ray photoelectron spectroscopy binding energy, and hard-soft acid-base principle verified the spontaneity of the central-metal-exchange reaction. The four materials were applied to a triboelectric nanogenerator (TENG), and the output performance law of ZUT-75 was Co-MT > Zn-MT > Cu-MT > Mn-MT. Among them, the charge and power densities of Co-MT were up to 127.05 μC m-2 and 3280.50 mW m-2. When the density functional theory calculation and variable-temperature magnetic susceptibility test results were combined, it was concluded that low metal-ion-coupling degree promoted the formation and transfer of contact electrifications, which greatly improved the output performance of the TENG. This work provided a new idea for improving the output performance of the TENG.

Two novel cadmium coordination polymers bearing viologen-derived ligand: Structure and photochromism properties

Two novel cadmium viologen coordination polymers (CPs) {[Cd(BTC)(H2O)]·(Mebpy)}n (1) and {[Cd1.5(Mebpy)(BDC)1.5Cl]·(DMF)}n (2) (Mebpy+ = N-methyl-4,4′-bipyridinium cation, DMF = N,N-Dimethylformamide) were prepared in the reaction of CdCl2 with different aromatic carboxylic acid ligands such as 1,3,5-benzenetricarboxylic acid (H3BTC) or 1,4-dicarboxybenzene acid (H2BDC) under hydrothermal conditions in the presence of N-carboxymethyl-4,4′-bipyridinium chloride (CEbpy·Cl). Single-crystal structure analysis revealed that the Cd(II) ions are bridged by BTC3- anions to form a 3D structure with the Mebpy+ cations occupying channel pores in compound 1, while the metal ions are bridged by BDC2- and Cl- anions to form a 3D structure with Mebpy+ cations in compound 2. Interestingly, it has been found that the structure of the two compounds depends on aromatic carboxylic acid ligands. Compounds 1 and 2 exhibit photochromic behavior under xenon lamp irradiation, accompanied by visible color changes from original color to blue.

Applicability of Reddish-Orange Light Emitting Samarium (III) Complexes for Biomedical and Multifunctional Optoelectronic Devices

Six crimson samarium (III) complexes based on β-ketone carboxylic acid and ancillary ligands were synthesized by adopting the grinding technique. All synthesized complexes were investigated via elemental analysis, infrared, UV-Vis, NMR, TG/DTG and photoluminescence studies. Optical properties of these photostimulated samarium (III) complexes exhibit reddish-orange luminescence due to 4G5/2 → 6H7/2 electronic transition at 606nm of samarium (III) ions. Further, energy bandgap, color purity, CIE color coordinates, CCT and quantum yield of all complexes were determined accurately. Replacement of water molecules by ancillary ligands enriched these complexes (S2-S6) with decay time, quantum yield, luminescence, energy bandgap and biological properties than parent complex (S1). Interestingly, these efficient properties of complexes may find their applications in optoelectronics and lighting systems. In addition to these, the antioxidant and antimicrobial assays were also investigated to explore the applications in biological assays.

Size control of cobalt nanoparticles by adjusting the linear carboxylic acid ligand chain length

Size control in the synthesis of Co nanoparticles (NPs) through thermolysis of Co2(CO)8 is achieved by adjusting the chain length of linear carboxylic acids used as ligands. As the chain length increases, steric effects reduce the reactivity of the carboxylic acids, thereby slowing the nucleation rate. In the subsequent growth phase, completing deposition of Co precursor onto fewer nuclei yields an increased NP size. Oxidation of Co NPs under ambient atmosphere causes formation of an antiferromagnetic CoO shell that can exchange couple to the Co core, resulting in exchange bias. The superparamagnetic blocking temperature (TB), coercivity (HC), and exchange shift (HEB) strongly depend on the size of the NP, and the most pronounced effects of exchange bias are observed for the smallest Co core size.

An anionic Zn-MOF composed of 1D columnar SBUs for highly C2H2/CH4 selective adsorption, dye adsorption and fluorescence sensing.

An anionic three-dimensional framework {(Me2NH2)2[Zn8(L)6(ad)4(μ4-O)]·10DMF·11H2O}(Zn-MOF, L2- = 4,4'-(3-aminopyridine-2,5-diyl)dibenzoic acid; ad- = adeninate) with a column-layered structure was synthesized. Structural studies show that the Zn-MOF has octahedral cages [Zn8(ad)4(μ4-O)], the adjacent cages are connected by O atoms to form 1D columnar SBUs, and every four SBUs are connected by L2- to form a square channel 3D framework. Gas adsorption studies show that the BET and Langmuir surface areas of Zn-MOF are 1370.31 and 1478.04 m2 g-1, respectively, and the total pore volume for single-point adsorption is 0.528 cm3 g-1. The surface of the pores of the Zn-MOF is occupied by open metal sites and uncoordinated carboxyl groups, showing good capture ability for C2H2 and good adsorption selectivity for C2H2/CH4. More importantly, the free (CH3)2NH2+ ions present in the pores of the columnar layered Zn-MOF can cation-exchange with MB, MV, and RhB ions in aqueous solution. Therefore, Zn-MOF can not only effectively adsorb the cationic dyes MB, MV, and RhB, but also exhibit particularly selective sorption towards the mixed anion and cation dyes MB/MO and MV/MO. In addition, a series of fluorescence experiments show that Zn-MOF has good fluorescence properties, exhibiting highly selective and sensitive fluorescence detection and recognition performance for Fe3+ ions in aqueous solution with a low detection limit.

Near-Infrared Luminescence and Magnetism of Several Lanthanide Polymers by Biphenyl Carboxylic Acid Ligand

Near-Infrared Luminescence and Magnetism of Several Lanthanide Polymers by Biphenyl Carboxylic Acid Ligand

Carboxylic acid ligand substituent impacts hydrosilylation activity of platinum single atom catalysts on ceria

Carboxylic acid substitution in 1,10-phenanthroline-5,6-dione ligands bind to surface hydroxy groups and result in higher ligand loading for metal–ligand single-atom Pt catalysts on CeO2, thereby allowing excellent hydrosilylation catalysis.

Structures, fluorescence and magnetism of a series of coordination polymers driven by a tricarboxypyridine ligand

Pyridine carboxylic acid ligand H3cppa was used to construct metal complexes by a hydrothermal reaction, and eight new complexes were constructed. Luminescence behavior and magnetic properties of complexes were investigated.

New Mn(II)-coordination polymer based on flexible benzimidazol ligand: crystal structure and treatment on osteosarcoma

In this study, a Mn(II)-based coordination polymer with the chemical composition of {[Mn(L)(TBTA)(H 2 O) 2 ]·H 2 O} n ( 1 ) was prepared by reacting Mn(OAc) 2 ·2H 2 O with the flexible ligand 1,4-bis(5,6-dimethylbenzimidazol-1-yl)-2-butylene in the aid of the carboxylic acid ligand tetrabromoterephthalic acid (H 2 TBTA) through the mixed-ligand method. Its application values on osteosarcoma were measured, and the internal principle was discussed simultaneously. The inhibitory activity of the new compound on the multiplication of osteosarcoma cells was evaluated using the Cell Counting Kit-8 detection kit. The facilitation of the LKB1-mTORC1 signaling pathway was estimated via real-time RT-PCR.

미세다공성 Zn(II)-MOF의 아세틸렌 선택 흡착과 LL-37을 이용한 간암에 대한 항암효과 연구

초록·키워드 목차 오류제보하기 By employment of a semi-rigid carboxylic acid ligand 5,5" -((5-carboxy-1,3-phenylene)bis(azanediyl))diiso- phthalic acid (H5L) with the -NH- joints, a new porous metal-organic framework (MOF) based on Zn(II) ions as nodes has been generated in success, and its chemical formula is {[Zn₃(μ₃-OH)(L)(H₂O₃)]·3DEF·H₂O}n (1). Owing to its Lewis basic -NH- joints and the π-electron-rich benzene rings on the skeleton, the activated complex 1 offers a favourable pore environment for binding C₂H₂ in preference to CO₂ and CH₄. The inhibitory activity of compound on the liver cancer viability was determined through exploiting the Cell Counting Kit-8 kit. Afterwards, the invasion and migration ability for the liver cancer cells was measured after indicated treatment. Multiple binding interactions are identified by performing the molecular docking simulation, indicating the stabilization effect of the Zn complex towards the target protein, and therefore, the proposed drug molecule exhibits good anticancer activities. #metal-organic framework #porous framework #gas separation #liver cancer #molecular docking AbstractIntroductionExperimentalResults and DiscussionConclusionsReferences

One amino-functionalized luminescence sensor demonstrating high sensitivity and selectivity for detecting Al3+ and Cu2+ as well as its luminescent mixed matrix membranes and test papers

A novel 3D Zn-based coordination polymer (NH2-LCU-110, LCU names Liaocheng University) with the formula [Zn(L1)(bpea)n (H2L1 ​= ​2-aminoterephthalic acid, bpea ​= ​1,2-bis(4-pyridyl)ethane), was hydrothermally synthesized from a flexible nitrogen-containing carboxylic acid ligand with various coordination modes as main ligands and nitrogen-containing auxiliary ligand with different structures. NH2-LCU-110 demonstrates an interesting 5-fold interpenetrating diamond structure. Luminescence measurements reveal that this complex has obvious emission enhancement and quenching towards Al3+ and Cu2+, respectively. The mixed matrix membranes (MMMs) incorporating NH2-LCU-110 and poly(methyl methacrylate) (PMMA) as well as simple test papers were both prepared for potential application. The MMMs can quickly detect Al3+ and Cu2+ and the original emission could be regenerated by lifting from the analytical solutions, demonstrating its fast response and good selectivity. The sensing mechanism was investigated in details by various measurements and compared with isostructural complex LCU-110 without –NH2 groups. All observations indicate that introduction of Lewis basic –NH2 groups can enhance the intermolecular interactions between the frameworks of coordination polymers and sensing analytes (Al3+ and Cu2+).

Design, Synthesis and Photoluminescence Sensing Property of a Ni‐Organic Material Achieved from 2,6‐Di(1H‐imidazol‐1‐yl) Naphthalene and Carboxylic Acid Ligands

AbstractA new metal‐organic framework (MOF) compound, [Ni(L)(IDC)(H2O)] ⋅ 0.5 L (1), (H2IDC=4,4′‐iminodibenzoic acid), was synthesized by solvothermal reaction of 2,6‐di(1H‐imidazol‐1‐yl)naphthalene (L) and dicarboxylic acid ligands with nickel salt. The results of single crystal diffraction show that the framework belongs to the P21/c space group and has a unique infinite one‐dimensional (1D) chain structure. They are further linked together through imidazole interaction and finally form a three‐dimensional (3D) structure. The crystal structure was characterized by Powder X‐ray diffraction (PXRD), thermogravimetric analyses (TGA), infrared spectra (IR) and elemental analyses (EA). Meanwhile, the thermal stability and luminescence properties of the crystal were tested. It was found that 1 could recognize acetone molecules by luminescence quenching. It has proved itself an efficient sensor for acetone at low con‐centration.

A Water-Soluble Polyacid Polymer Based on Hydrophilic Metal-Organic Frameworks Using Amphoteric Carboxylic Acid Ligands as Linkers for Hydroxycamptothecin Loading and Release In Vitro.

The poor water solubility and severe side effects of hydroxycamptothecin (HCPT) limit its clinical application; therefore, it is necessary to synthesize applicable nanodrug carriers with good solubility to expand the applications of HCPT. In this study, a hydrophilic metal–organic framework (MOF) with amphoteric carboxylic acid ligands as linkers was first synthesized and characterized. Then, water-soluble acrylamide and methacrylic acid were applied as monomers to prepare a water-soluble polyacid polymer MOF@P, which had a solubility of 370 μg/mL. The effects of the MOF@P material on the HCPT loading and solubility were investigated. The results showed that the polymer material could improve the HCPT solubility in water. Moreover, the in vitro release study indicated that the MOF@P polymeric composite exhibited a sustained-release effect on HCPT, with a cumulative release rate of 30.18% in 72 h at pH 7.4. Furthermore, the cytotoxicity test demonstrated that the hydrophilic MOF and the MOF@P had low cell toxicities. The results indicate that the prepared MOF@P polymeric complex can be applied for the sustained release of HCPT in clinics.

Unlocking active metal site of Ti-MOF for boosted heterogeneous catalysis via a facile coordinative reconstruction

Constructing sophisticated hollow structure and exposing more metal sites in metal-organic frameworks (MOFs) can not only enhance their catalytic performance but also endow them with new functions. Herein, we present a facile coordinative reconstruction strategy to transform Ti-MOF polyhedron into nanosheet-assembled hollow structure with a large amount of exposed metal sites. Importantly, the reconstruction process relies on the esterification reaction between the organic solvent, i.e. ethanol and the carboxylic acid ligand, allowing the conversion of MOF without the addition of any other modulators and/or surfactants. Moreover, the surface and internal structure of the reconstructed MOF can be well tuned via altering the conversion time. Impressively, the reconstructed MOF exhibits ∼5.1-fold rate constant compared to the pristine one in an important desulfurization reaction for clean fuels production, i.e. the oxidation of dibenzothiophene.

Development of Axially Chiral Styrene-Type Carboxylic Acid Ligands via Palladium-Catalyzed Asymmetric C-H Alkynylation.

A weakly coordinated carboxylate-directed palladium-catalyzed atroposelective C-H alkynylation method for the development of novel axially chiral styrene-type carboxylic acids is disclosed. This transformation exhibits good yields (up to 85%), excellent enantiocontrol (up to 99% ee), and mild conditions. Notably, the synthetic utility of the resulting alkynyl carboxylic acid derivatives was demonstrated by various derivatizations as well as their potential as chiral ligands in asymmetric C-H activations.

Luminescence and cytotoxic study of red emissive europium(III) complex as a cell dye

A novel non-toxic red luminescent Eu(III)-complex, (Na[Eu(Fmpc)4(H2O)4]∙3H2O), based on a carboxylic acid ligand was synthesized and characterized by several techniques, such as elemental analysis, MALDI TOF spectrometry, thermogravimetric analyses, UV–vis, FT-IR, and photoluminescence spectroscopies; also its structure was optimized theoretically by the AM1 sparkle model. The Gd(III)-complex, (Na[Gd(Fmpc)4(H2O)3]∙4H2O), was also synthesized and characterized, to evaluate the Fmpc ligand triplet excited state, revealing that the energy of the ligand is suitable to sensitize the similar Eu(III)-complex, indicating a high sensitization rate of the Fmpc ligand to Eu3+ ion with 98% efficiency. The Na[Eu(Fmpc)4(H2O)4]∙3H2O luminescent properties were investigated, and its excited state lifetime was also determined as 0.76 ms in acetonitrile solution. The complex relative quantum yield was estimated to be 27.9%, evidencing that the Fmpc ligand is efficient in transferring the absorbed energy to the europium(III) ion emitting level. Furthermore, the cytotoxicity of Na[Eu(Fmpc)4(H2O)4]∙3H2O was tested in CHO-k1 cells by the MTT assay, and no cytotoxicity was observed at 24 h of exposure within the concentrations tested (25–200 µg/mL). Its use for cell imaging was also evaluated by fluorescence and confocal microscopies. Our findings indicated that Na[Eu(Fmpc)4(H2O)4]∙3H2O complex exhibited great luminescent properties, it is non-toxic, and it has potential for bioimaging application as a luminescent dye.

Structure and photocatalytic performance of a metallacycle complex based on flexible carboxylic acid ligand

A new compound of {[Cu2(L)2(2,2′-bipy)2(H2O)2]·2H2O}n (1) (H2L = 1,3-bis(4′-carboxylatophenoxy)benzene, 2,2′-bipy = 2,2′-bipyridine), was prepared and full characterized. 1 shows a metallacycle unit, which was further extended into 3D supramolecular motif through the π-π packing and H-bonded interactions. 1 obtained effectively photocatalytic performance to the disintegration of Rhodamine B (Rh B) compared to the dyes of basic green (BG), methyl violet (MV) and methylene blue (MB). In addition, the plausible mechanism displayed by 1 for the catalytic degradation toward Rh B was proposed using the trapping method and LC-MS studies.