Tricarboxylate Ligand Research Articles

Asymmetric Charge Distribution in One-dimensional Metal-Organic Assemblies to Promote Photocatalytic Hydrogen Evolution.

The local charge distribution of photocatalyst is crucial to the catalytic activity due to its influence on the charge separation process. Herein, we report two one-dimensional Ni-based metal-organic assemblies for efficient photocatalytic hydrogen evolution without using noble-metal cocatalysts. By adjusting the aromatic ring in the center of the tricarboxylic ligand, the photocatalytic hydrogen evolution activity was increased from 1715 to 2652 μmol h-1 g-1. The detailed mechanism study shows that the introduced nitrogen atoms in the ligands of the metal-organic coordination assembly could modulate the local charge distribution, and yielding a significant enhancement of the molecular dipole moment which engenders a propulsive force for the effective separation and transport of photoinduced charge carriers. This work provides insights into the local charge distribution via ligand modulation for enhancing the activity of photocatalysts.

Syntheses, structures, magnetism and photocatalytic degradation of methylene blue dye of two copper complexes based on a semirigid tricarboxylate ligand

Two Cu(II)-complexes [Cu(Hcpota)(4,4′-bpy)(H2O)]n1 and [Cu(Hcpota)(1,4-bib)(H2O)]n2 based on a semirigid ligand 2-(4-carboxyphenoxy)terephthalic acid (H3cpota) were solvothermally prepared and characterized. Complexes 1 and 2 exhibit an unprecedented 2D 4-connected framework with a {44.62} topology, comprising the Cu(II) ion with square pyramidal coordination. The three-dimensional frameworks are constructed by O–H···O hydrogen bonds. Magnetization analyses were conducted and revealed that complexes 1 and 2 have ferromagnetic properties. The photodegradation of Methylene blue dye was studied based on 1 and 2 as photocatalysts. The results indicated that complexes 1 and 2 exhibited remarkable photodegradation efficiencies of 86.9 % and 97.0 % after 24 min, respectively. Furthermore, pseudo-first-order kinetics was assumed for the photocatalytic reaction with a rate constant of 0.052 and 0.109 min−1 for 1 and 2. The impact of factors, including the initial concentration of MB, catalyst dosage, pH value, H2O2 concentration, and temperature on the degradation process of MB was thoroughly examined. The complexes exhibited excellent recyclability and stability as photocatalysts. Trapping experiments and LC-MS studies revealed that the primary active species responsible for the degradation reaction are hydroxyl radicals (·OH) and holes (h+).

A new Mn(Ⅱ)-based metal-organic framework: synthesis, characterization, ferrimagnetic behavior and catalytic conversion of CO2 to cyclic carbonates

A new three-dimensional (3D) metal–organic framework (MOF) [Mn3(bqca)2(DMF)4]n (1) is constructed based on a tricarboxylate ligand 2,3-di-(4-carboxyphenyl)-quinoline-6-carboxylic acid (H3bqca) through solvothermal reaction. The structure, composition and stability of the complex were fully characterized by single crystal X-ray diffraction, powder X-ray diffraction, infrared spectrum and thermogravimetric analysis. The results show that 1 has a 3D microporous framework and exhibits high thermal stability up to 450 ℃. Direct-current magnetic susceptibility reveals that 1 is a rare ferrimagnetic homospin system. Importantly, 1 can effectively catalyze the cycloaddition reaction of CO2 with epoxides to generate cyclic carbonates with high yields and selectivity, and it can also be recycled at least five times without a noticeable change in catalytic efficiency.

Detection of nitroaromatics by a Zn(II)-containing coordination polymer derived from a 1,2,3-triazole-based tricarboxylate ligand

The Dimroth azide–enolate cycloaddition between dimethyl 5-azidoisophthalate and ethyl acetoacetate was used to generate 5-(4-carboxy-5-methyl-1H-1,2,3-triazol-1-yl)isophthalic acid (H3L) as a novel tricarboxylate ligand with a 1,2,3-triazole ring in the central unit with a view to employ it in the preparation of coordination polymers. The reaction of this ligand with Zn(NO3)2·6H2O in a mixture of N,N-dimethylformamide (DMF) and water at 95 °C for 72 h afforded [Zn4L2(OH)2(H2O)DMF2]n, which has been characterized by single crystal X-ray crystallography, infrared spectroscopy, thermogravimetry, powder X-ray diffraction and elemental analysis. The fluorescence of this coordination polymer was investigated, and its ability to detect various nitroaromatics by fluorescence quenching was examined. 4-Nitrophenol, 2,4-dinitrophenol, 2,4,6-trinitrophenol and 4-nitrotoluene have been identified as the aromatic nitroderivatives for which the coordination polymer exhibits a fluorescence quenching in the range of 91% to 82%.

Proton conductive properties of one water-stable nickel(II) supramolecule bearing tri-pyridyl and tri-carboxylate ligand

The construction of highly stable complexes using azacyclic carboxylate ligands is an important way to obtain crystalline proton-conducting materials with high performance. In this paper, one three-dimensional supramolecule, [Ni(H2ttp)2]⋅3H2O (1) [H3ttp = 4-(2,4,6-tricarboxyphenyl)-2,2′,6,2′′-terpyridine] has been prepared according to literature approach with slight modification. Firstly, its molecular structure was determined by powder X-ray diffraction, infrared spectroscopy, and elemental analysis, followed by a thermogravimetric determination to confirm its thermal and water stability. The N2 and water H2O adsorption abilities were also measured. Electrochemical experiments have shown 1 to be a typical temperature and humidity-dependent proton conductor with an optimum proton conductivity of 4.00 × 10−4 S/cm (98% RH/100 °C). A large number of uncoordinated carboxylate units and crystalline water molecules, as well as the H-bonding networks inside the framework, provide effective channels for proton transportation. The proton-conductive mechanism was further postulated following the calculated value of activation energy.

Two Proton Conductive Coordination Polymers Constructed by an Unprecedented Structural Transformation of a Phosphine-Based Tricarboxylate Ligand

The phosphine-based tricarboxylate 2-(3,3′-dioxo-1λ5-1,1′-(3H,3′H)-spirobi[2,1-benzoxaphosphol]-1-yl)benzoic acid (L) has been intensely studied due to its unique configuration and readily oxidizable phosphorus center. However, the coordination of L with metals have been largely ignored in the field of coordination polymers (CPs). Herein, we report two CPs, [Zn3(L1)2(dib)2(H2O)]·9H2O (1) and [Cu3(L2)2(dib)2]·3H2O (2) (H3L1 = tris(2-carboxyphenyl)phosphine oxide, H3L2 = 2,2′-phosphinico-dibenzoic acid, dib = 1,4-di(1H-imidazol-1-yl)butane), synthesized based on L. Strikingly, despite the initial use of L, the structures of 1 and 2 reveal that L undergoes two unprecedented in situ structural changes after coordination with the metal ion. In 1, L is transformed to the phosphine oxide derivative L1, while in 2, it is transformed to the phosphinic acid derivative L2. With the aid of the flexible ligand dib, the one-dimensional (1D) chain structure of 1 and three-dimensional (3D) supramolecular structure of 2 were constructed. For 1 and 2, especially in 1, there are abundant hydrogen bonds between the framework and the lattice water molecules, which are conducive to the formation of excellent hydrophilic channels and the transport of protons. Electrochemical experimental results show that 1 and 2 exhibit high proton conductivities (σ) of more than 10–4 S cm–1 over a wide temperature range of 303–353 K and low activation energies (Ea) at 98% relative humidity. Compared with the σ value of the initial ligand L (3.12 × 10–5 S cm–1), the best σ values of 1 and 2 are improved by 28 times and 6 times, respectively, and Ea is also reduced from 0.39 to 0.13 eV for 1 and 0.12 eV for 2. This is the first report of proton-conducting polymers based on a phosphine-based carboxylate ligand, involving two in situ structural transitions of the ligand.

Syntheses, characterization of Ni(II)/Zn(II) complexes derived from flexible tricarboxylate ligand and 2,2′-bipyridine and their methyl violet dye photodegradation applications

Three new complexes comprising Ni(II) and Zn(II) metal centers having compositions [Zn2(HL)2(bpy)2(H2O)2] (1), [Ni(H2L)(bpy)(H2O)2(OH)] (2) and [Ni(H2L)2(bpy)2] (3) have been synthesized by adopting mixed ligand strategy using 4′-(3,4- dicarboxylphenyloxy) -4-biphenylcarboxylic acid (H3L) as main ligand and 2,2′-bipyridine (bpy) as co-ligand. These complexes have been characterized by microanalyses, FTIR and single crystal X-ray diffraction technique. The single crystal X-ray analyses reveal that all the three complexes have 2D supramolecular network constructed by hydrogen bonding interactions. These complexes have been employed as photocatalysts for the photodegradation of methyl violet (MV) dye. The photocatalytic experiments reveal that amongst all three complexes, the complex 2 exhibits best photocatalytic performance and degrades 92.8% of MV in time span of 100 min. The plausible photocatalytic degradation mechanism have been proposed with the help of trapping experiments and density of states calculations.

A rare heptanuclear cluster-based yttrium-organic framework with an aromatic tricarboxylate ligand for blue LED application

A rare heptanuclear cluster-based yttrium-organic framework with an aromatic tricarboxylate ligand for blue LED application

Ortho Effects of Tricarboxylate Linkers in Regulating Topologies of Rare-Earth Metal-Organic Frameworks.

A linker design strategy is developed to attain novel polynuclear rare-earth (RE) metal-organic frameworks (MOFs) with unprecedented topologies. We uncover the critical role of ortho-functionalized tricarboxylate ligands in directing the construction of highly connected RE MOFs. The acidity and conformation of the tricarboxylate linkers were altered by substituting with diverse functional groups at the ortho position of the carboxyl groups. For instance, the acidity difference between carboxylate moieties resulted in forming three hexanuclear RE MOFs with novel (3,3,3,10,10)-c wxl, (3,12)-c gmx, and (3,3,3,12)-c joe topologies, respectively. In addition, when a bulky methyl group was introduced, the incompatibility between the net topology and ligand conformation guided the co-appearance of hexanuclear and tetranuclear clusters, generating a novel 3-periodic MOF with a (3,3,8,10)-c kyw net. Interestingly, a fluoro-functionalized linker prompted the formation of two unusual trinuclear clusters and produced a MOF with a fascinating (3,8,10)-c lfg topology, which could be gradually replaced by a more stable tetranuclear MOF with a new (3,12)-c lee topology with extended reaction time. This work enriches the polynuclear clusters library of RE MOFs and unveils new opportunities to construct MOFs with unprecedented structural complexity and vast application potential.

Integrating Self-Partitioned Pore Space and Amine Functionality into an Aromatic-Rich Coordination Framework with Ph Stability for Effective Purification of C2 Hydrocarbons.

A great demand for high-purity C2 hydrocarbons calls for the development of chemically stable porous materials for the effective isolation of C2 hydrocarbons from CH4 and CO2. However, such separations are challenged by their similar physiochemical parameters and have not been systematically studied to date. In this work, we reported a cadmium-based rod-packing coordination framework compound ZJNU-140 of a new 5,6,7-c topology built up from a custom-designed tricarboxylate ligand. The metal-organic framework (MOF) features an aromatic-abundant pore surface, uncoordinated amine functionality, and self-partitioned pore space of suitable size. These structural characteristics act synergistically to provide the MOF with both selective recognition ability and the confinement effect toward C2 hydrocarbons. As a result, the MOF displays promising potential for adsorptive separation of C2-CH4 and C2-CO2 mixtures. The IAST-predicted C2/CH4 and C2/CO2 adsorption selectivities, respectively, fall in the ranges of 7.3-10.2 and 2.1-2.9 at 298 K and 109 kPa. The real separation performance was also confirmed by dynamic breakthrough experiments. In addition, the MOF can maintain skeleton intactness in aqueous solutions with a wide pH range of 3-11, as confirmed by powder X-ray diffraction (PXRD) and isotherm measurements, showing no loss of framework integrity and porosity. The excellent hydrostability, considerable uptake capacity, impressive adsorption selectivity, and mild regeneration make ZJNU-140 a promising adsorbent material applied for the separation and purification of C2 hydrocarbons.

Synthesis, crystal structures and electrocatalytic properties of 2D and 3D Co(Ⅱ) Coordination polymers based on semi-rigid tricarboxylic acid ligand

The tricarboxylic ligand, 4′,4′,4′-[(trimethylamino)]-tris[(1,1′-biphenyl)-2-carboxylic acid] (H3TMCA), is designed and synthesized to self-assembly two novel cobalt coordination polymers, formulated as {[Co2(TMCA)(OH)(DMF)(H2O)]}n (1), {[Co3(TMCA)2]}n (2). Interesting, due to the flexibility of the H3TMCA, the final frameworks of 1-2 can change depending on the reaction of temperature and solvents. Complex 1 is a (3, 6)-connected of type kgd two-dimensional (2D) network with a point (Schlafli) symbol of {43}2{46. 66. 83}. Complex 2 is a (4, 6)-connected 2-nodal three-dimensional (3D) net with point (Schlafli) symbol of {415}2{42. 84}3. In addition, the electrocatalytic activity of these Co-CPs were studied in detail.

Ligand Conformation Fixation Strategy for Expanding the Structural Diversity of Copper-Tricarboxylate Frameworks and C2H2 Purification Performance Studies.

Structural and functional expansion of metal-organic frameworks (MOFs) is fundamentally important because it not only enriches the structural chemistry of MOFs but also facilitates the full exploration of their application potentials. In this work, by employing a dual-site functionalization strategy to lock the ligand conformation, we designed and synthesized a pair of biphenyl tricarboxylate ligands bearing dimethyl and dimethoxy groups and fabricated their corresponding framework compounds through coordination with copper(II) ions. Compared to the monofunctionalized version, introduction of two side groups can significantly fix the ligand conformation, and as a result, the dual-methoxy compound exhibited a different network structure from the mono-methoxy counterpart. Although only one almost orthogonal conformation was observed for the two ligands, their coordination framework compounds displayed distinct topological structures probably due to different solvothermal conditions. Significantly, with a hierarchical cage-type structure and good hydrostability, the dimethyl compound exhibited promising practical application value for industrially important C2H2 separation and purification, which was comprehensively demonstrated by equilibrium/dynamic adsorption measurements and the corresponding Clausius-Clapeyron/IAST/DFT theoretical analyses.

Trans-[Ni(pdm)2]2+ (pdm = 2-pyridinemethanol) as a reliable synthon for isoreticular metal–organic frameworks of linear dicarboxylates

trans-[Ni(pdm)2]2+ (pdm ​= ​2-pyridinemethanol) proved to be a reliable synthon for the construction of isoreticular metal–organic frameworks (MOFs) of linear dicarboxylates, as exemplified by three one-dimensional (1D) MOFs [Ni(pdm)2(BDC)]n (1), [Ni(pdm)2(NDA)]n∙nDMF (2), and [Ni(pdm)2(ADC)]n (3) (H2BDC ​= ​1,4-benzenedicarboxylic acid; H2NDA ​= ​naphthalene-2,6-dicarboxylic acid; H2ADC ​= ​9,10-anthracenedicarboxylic acid; DMF ​= ​N,N-dimethylformamide) which shared identical connectivity. A dinuclear cluster [Ni2(pdm)4(HBTC)2]∙2DMF (4) was formed from tricarboxylate ligand BTC (H3BTC ​= ​benzene-1,3,5-tricarboxylic acid) with the two pdm ligands aligned cis to one other. Single-crystal structure analysis indicated that the 1D chains of 1 − 3 were stacked at different angles in the solid state, resulting in different crystal packing patterns, including a pseudo Kagome-like cross-section for 1, 1D channels for 2 with DMF guest species, and a non-porous structure for 3.

Water-Mediated Proton Conduction in Metal–Organic Frameworks with High Water Stability Constructed by a Terpyridine Tricarboxylate Ligand

Water-Mediated Proton Conduction in Metal–Organic Frameworks with High Water Stability Constructed by a Terpyridine Tricarboxylate Ligand

CdII-based compound as a multi-responsive fluorescent probe for sensing FeIII cations and CrVI oxyanions.

A new luminescent CdII compound, poly[[μ2-1,4-bis(1H-imidazol-1-yl)benzene]{μ2-5-[(3-carboxylphenoxy)methyl]isophthalato}cadmium(II)], [Cd(C16H10O7)(C12H10N4)]n or [Cd(HL)(1,4-bib)]n {H3L is 5-[(3-carboxyphenoxy)methyl]isophthalic acid and 1,4-bib is 1,4-bis(1H-imidazol-1-yl)benzene}, I, has been synthesized successfully from CdII and a semirigid tricarboxylic ligand under hydrothermal conditions. Structure analysis shows that I is a two-dimensional structure with the point symbol {44.62}. The three-dimensional framework is constructed by O-H...O hydrogen bonds and π-π stacking interactions. Furthermore, the obtained CdII compound displays high solvent stability and excellent thermal stability, as shown by powder X-ray diffraction and thermogravimetry measurements. Studies of the luminescence properties reveal that compound I can act as a promising luminescent sensor for detecting FeIII cations and CrVI oxyanions with high selectivity and low detection limits (0.19 µM for Fe3+ and 1.13 µM for Cr2O72-), and is additionally free from the interference of other ions. The mechanism of selective quenching was studied by measuring the UV-Vis absorption of the host compound and the target analytes.

Zwitterionic and Anionic Polycarboxylates as Coligands in Uranyl Ion Complexes, and Their Influence on Periodicity and Topology.

The three zwitterionic di- and tricarboxylate ligands 1,1'-[(2,3,5,6-tetramethylbenzene-1,4-diyl)bis(methylene)]bis(pyridin-1-ium-4-carboxylate) (pL1), 1,1'-[(2,3,5,6-tetramethylbenzene-1,4-diyl)bis(methylene)]bis(pyridin-1-ium-3-carboxylate) (mL1), and 1,1',1″-[(2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)]tris(pyridin-1-ium-4-carboxylate) (L2) have been used as ligands to synthesize a series of 15 uranyl ion complexes involving various anionic coligands, in most cases polycarboxylates. [(UO2)2(pL1)2(cbtc)(H2O)2]·10H2O (1, cbtc4- = cis,trans,cis-1,2,3,4-cyclobutanetetracarboxylate) is a discrete, dinuclear ring-shaped complex with a central cbtc4- pillar. While [UO2(pL1)(NO3)2] (2), [UO2(pL1)(OAc)2] (3), and [UO2(pL1)(HCOO)2] (4) are simple chains, [(UO2)2(mL1)(1,3-pda)2] (5, 1,3-pda2- = 1,3-phenylenediacetate) is a daisy chain and [UO2(pL1)(pdda)]3·10H2O (6, pdda2- = 1,2-phenylenedioxydiacetate) is a double-stranded, ribbon-like chain. Both [UO2(pL1)(pht)]·5H2O (7, pht2- = phthalate) and [(UO2)3(mL1)(pht)2(OH)2] (8) crystallize as diperiodic networks with the sql topology, the latter involving hydroxo-bridged trinuclear nodes. [(UO2)2(pL1)(c/t-1,3-chdc)2] (9, c/t-1,3-chdc2- = cis/trans-1,3-cyclohexanedicarboxylate) and [UO2(pL1)(t-1,4-chdc)]·1.5H2O (10, t-1,4-chdc2- = trans-1,4-cyclohexanedicarboxylate) are also diperiodic, with the V2O5 and sql topologies, respectively. Both [(UO2)2(mL1)(c/t-1,4-chdc)2] (11) and [(UO2)2(pL1)(1,2-pda)2] (12, 1,2-pda2- = 1,2-phenylenediacetate) crystallize as diperiodic networks with hcb topology, and they display threefold parallel interpenetration. [HL2][(UO2)3(L2)(adc)3]Br (13, adc2- = 1,3-adamantanedicarboxylate) contains a very corrugated hcb network with two different kinds of cells, and the uncoordinated HL2+ molecule associates with the coordinated L2 to form a capsule containing the bromide anion. [(UO2)2(pL1)(kpim)2] (14, kpim2- = 4-ketopimelate) is a three-periodic framework with pL1 molecules pillaring fes diperiodic subunits, whereas [(UO2)2(L2)2(t-1,4-chdc)](NO3)1.7Br0.3·6H2O (15), the only cationic complex in the series, is a triperiodic framework with dmc topology and t-1,4-chdc2- anions pillaring fes diperiodic subunits. Solid-state emission spectra and photoluminescence quantum yields are reported for all complexes.

Dual-responsive luminescent sensitivities of a 3D Co-CP with turn-on and ratiometric sensing toward ascorbic acid and turn-off detecting acetylacetone

By selecting the luminescent tricarboxylate ligand H3L, a novel 3D Co(II)-based coordination polymer (compound 1) with the formula [Co(HL) (bpe)] (H3L ​= ​5-(3,4-dicarboxylphenoxy) nicotic acid; bpe ​= ​1,2-bis(4-pyridyl) ethylene) has been solvothermally synthesized, which features a 2-nodal (3, 5)-connected net with the Schläfli sign of (63·69·8). Particularly, it is found that compound 1 possesses good chemical and thermal stability. Luminescence measurements indicate that this material shows rare ratiometric turn-on luminescence response toward ascorbic acid (AA). The relative luminescent intensity ratio (I362/I410) increases linearly with increasing AA concentration in the 0–25 ​μM range with detection limit of 0.68 ​μM. Compound 1 could also respond to acetylacetone through luminescence turn-off mechanism. The limit of detection is estimated to be 1.35 ​μM. Both proposed sensing systems show good sensitivity, high selectivity and excellent anti-interference performance. In addition, the possible sensing mechanisms are also elaborately investigated.

Lewis acid-base integrated robust metal-organic framework and reconfigurable composite for solvent-free Biginelli condensation and tandem catalysis with size selectivity

Aiming at environmentally benign catalyses with less energy consumption, reduction in chemical usage and minimization of wastes, metal-organic frameworks (MOFs) combining basic functionality enriched pores and unsaturated metal centers (UMCs) is most promising. Alternatively, astute tuning of channel dimension in these materials can benefit much anticipated size-exclusive catalysis, whereas fabrication of flexible MOF-composite is imperative considering facile applicability over real-life platforms. The pillar-bilayered and hydrolytically robust MOF, built from tri-carboxylate ligand, linear linker and solvent-bound [Cd3(COO)6] secondary building unit exhibits N-functionality enriched porous channels and activation-driven generation of open metal sites. Benefiting from unique bifunctional character, the MOF acts as excellent solvent-free catalyst toward one-pot Biginelli reaction and deacetalization–Knoevenagel condensation under mild condition. Both the reactions transpire with broad substrate scope, high recyclability and superior activity to contemporary materials, wherein single-crystal X-ray diffraction is first time applied as product characterization tool. Judiciously designed control experiments validate individual catalytic routes, thereby substantiating the importance of contrasting pore-functionalities at the interface of structure–property synergism. To the best of three-component coupling and acid-base tandem catalysis, substrates with incompatible molecular dimension to that of the twofold interpenetration generated optimized pores exhibit insignificant conversion and demonstrate unprecedented pore-fitting-actuated size selectivity. In view of practically advanced and eco-friendly substrate design, reconfigurable MOF–cotton fiber composite is fabricated via in situ growth, which delivered excellent yields for both these reactions with comparable reusability to that of pristine framework, delineating a paradigm shift to smart, futuristic and green strategy in synergistic catalysis.

Rational design of three Co(II) coordination polymers based on a semirigid tricarboxylate ligand: Syntheses, structural variability, electrochemical behavior, magnetic and photocatalytic properties

Three novel Co(II) based coordination polymers (CPs) are fabricated using the 5-(2-carboxylphenoxy)isophthalic acid (H3L) and different N-donor configuration under the solvothermal conditions, namely, [Co2(L)(1,4-bibt)(μ3OH)]n (1), [Co(HL)(4,4′-bidpe)]n (2), and [Co(HL)(tib)]n (3) (1,4-bibt = 1,4-bis(imidazol-1-yl)butane, 4,4′-bidpe = 4,4′-bis(imidazolyl)diphenylether, tib = 1,3,5-tris(1-imidazolyl)benzene). The configuration of 1–3 are confirmed by various characterization analysis. The CP 1 possesses an unprecedented (3,10)-connected 3D architecture with a unique tetranuclear [Co4(µ3OH)2(COO)4]2+cluster. Interestingly, when the H3L ligands are not calculated, the whole structure of N-donor still shows a 3-fold interpenetrating dia 3D framework (3D + 3D → 3D). Moreover, CPs 2 and 3 are 3D supramolecular structure with significant differences structures. The CP 2 shows a 2D sql uninodal 4-connected 2D network with the Schläfli symbol (44•62), while CP 3 exhibits an unprecedented 2D framework. And both 2 and 3 construct 3D supramolecular architecture through H-bonds between the two adjacent 2D networks. Comparing CPs 1–3 shows that the N-donor ligands play a key role in adjusting the final structures. Furthermore, the electrochemical behavior, magnetic properties and photocatalytic activity of 1–3 are also discussed in details.

A Stable Y(III)-Based Amide-Functionalized Metal-Organic Framework for Propane/Methane Separation and Knoevenagel Condensation.

Here, a Y(III)-based metal-organic framework, JLU-MOF112 {[Y3(μ3-O)2(μ3-OH)(H2O)2(BTCTBA)2]·2[(CH3)2NH2]·5DMF·C6H5Cl·4H2O}, has been successfully synthesized under solvothermal conditions. JLU-MOF112 was constructed with amide-functionalized tricarboxylate ligands and Y(III)-based infinite chains, where the Y3 repeating units are arranged in a trans order. The overall framework could be viewed as a novel (3,5)-connected net with two types of channels along the [100] and [010] directions. JLU-MOF112 possesses a large BET surface area (1553 m2 g-1), a permanent pore volume (0.67 cm3 g-1), and outstanding thermal and chemical stability, which give JLU-MOF112 potential for the purification of natural gas, especially the equimolar separation of C3H8/CH4 with a high selectivity of 176. In addition, benefiting from the amide functional groups as Brønsted basic sites and the exposure of open metal sites as Lewis acid sites after activation, JLU-MOF112 can serve as a high-efficiency heterogeneous catalyst for Knoevenagel condensation by the reactions of malononitrile with benzaldehyde (yield of 98%, turnover number of 392, and turnover frequency of 3.27 min-1) and diverse aldehyde compounds. A rational mechanism was put forward that the Knoevenagel condensation was catalyzed by the synergistic effect of the Lewis acid sites and Brønsted basic sites, engendering the polarization of the carbonyl groups and the deprotonation of the methylene groups for nucleophilic attack.