Tribenzoic Acid Research Articles

A Eu/Tb mixed lanthanide coordination polymer with rare 2D thick layers: Synthesis, characterization and ratiometric temperature sensing

A series of lanthanide coordination polymers LnBTPTA (Ln = Eu, Tb, EuxTb1−x), was synthesized using a tricarbocylic ligand 4,4′,4′′-(benzene-1,3,5-triyltris(1H-pyrazole-3,1-diyl))tribenzoic acid (H3BTPTA). X-ray single crystal analyses reveal that the asymmetric unit cell contains seven crystallographically independent metal ions and seven crystallographically independent ligands which is quite unusual. The 3D framework is comprised of 2D thick layers stacked through van der Waals force, π-π interactions and hydrogen bonding interactions. Eu0.0316Tb0.9684BTPTA presents a dual-emission of Tb3+ at 543nm and Eu3+ at 617nm, and the intensity ratio shows an excellent linear relationship with the temperature changing in 25–225K. The relative sensitivity 0.45–5.12%K−1 is much higher than those have been reported in the same detection range.

Two-dimensional cobalt metal-organic frameworks for efficient C3H6/CH4 and C3H8/CH4 hydrocarbon separation

A Co-based two-dimensional (2D) microporous metal-organic frameworks, [Co2(TMTA)(DMF)2(H2O)2]·NO3−·DMF (UPC-32) has been synthesized based on 4,4′,4′′-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoic acid (H3TMTA). UPC-32 features a 2D microporous framework exhibits high adsorption of H2 (118.2cm3/g, 1.05wt%, at 77K), and adsorption heat (Qst) of CO2 (34–46kJ/mol). UPC-32 with narrow distance between layers (3.8Å) exhibits high selectivity of C3H6/CH4 (31.46) and C3H8/CH4 (28.04) at 298K and 1bar. It is the first 2D Co-MOF that showed selective separation of C3 hydrocarbon from CH4.

Construction of a novel Cd(II) coordination polymer based on a flexible tripodal carboxylic acid and bimid coligands

A new coordination polymer was solvothermally prepared based on a semi-rigid multidentate carboxylic acid ligand and benzimidazole (bimid) ligand (H3L=4,4′,4″-(((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(oxy))tribenzoic acid): [Cd2(L) (bimid) (DMF)2]·(DMF)3·(H2O)2 (1). The complex 1 was characterized by single crystal X-ray diffraction, infrared spectroscopy, thermogravimetry measurement, elemental analysis and X-ray powder diffraction. Structure analysis reveals that complex 1 displays a rare doubly-interpenetrating (3, 5)-connected hms network with a point symbol {63}{69.8}. Moreover, the fluorescence and gas adsorption properties of the compound 1 were also explored.

A simple and sensitive spectrofluorimetric method for the determination of sodium hexametaphosphate based on the Tb(iii)–TATAB complex

A “turn-off” fluorometric detection method for sodium hexametaphosphate (SHMP) with a terbium(iii) complex of 4,4′,4′′-((1,3,5-triazine-2,4,6-triyl)-tris(azanediyl))-tribenzoic acid (H3TATAB) is developed.

Two metal-organic frameworks with different configurations constructed from a flexible tripodal triaromatic acid

Two metal-organic frameworks [Ce2(L)2(DMF)4] (1), and [Ni3(HL2−)4(bpe)3(H2O)4]·[H2N(CH3)2+]2(DMF)6(H2O)8 (2) (H3L = 4,4′,4″-{[(2,4,6-trimethylbenzene-1,3,5-triyl)tris-(methylene)] tris(oxy)}tribenzoic acid, bpe = trans-4,4′-bipyridylethylene) have been solvothermally synthesized from a flexible tripodal ligand. Single-crystal X-ray diffraction shows that compound 1 features a 3,6-connected double-layer network which is further connected by weak π-π interactions between benzene rings to form a 3D porous network. Compound 2 exhibits an unprecedented (4,5)-connected (33.42.5.62.72)2(6.84.10) topology based on zigzag chains and straight chains. In addition, thermal stabilities and luminescent properties of 1 and 2 were investigated in the solid state.

Solvent‐Controlled Construction of Two 3D Manganese(II) Coordination Polymers Based on Flexible Tripodal Multicarboxylate Linker and Rod‐Shaped SBUs

AbstractTo further explore the coordination possibilities of the flexible tripodal ligand, 4,4′,4′′‐(benzene‐1,3,5‐triyl‐tris(oxy))tribenzoic acid (H3BTTB), two solvent‐controlled three‐dimensional (3D) manganese(II) coordination polymers, [Mn3(BTTB)2(H2O)4](H2O)2 (1) and [Mn3(BTTB)2(DMF)2](DMF)2 (2), were synthesized and characterized. Single crystal X‐ray diffraction analysis indicates that in the MnII complexes the BTTB ligands exhibit two coordination modes, which have not been reported previously. Complexes 1 and 2 involve different one‐dimensional (1D) rod‐shaped metal–carboxylate secondary building units (SBUs). The 1D SBUs are further extended to afford two different three‐dimensional (3D) frameworks with similar flu topology via linkage of the BTTB ligands. The results demonstrate that the reaction solvent as well as conformation and coordination mode of BTTB ligands play key roles on the formation of the final framework structures. Additionally, their luminescent properties were investigated.

Entangled Uranyl Organic Frameworks with (10,3)-b Topology and Polythreading Network: Structure, Luminescence, and Computational Investigation.

Two 3D uranyl organic frameworks (UOFs) with entangled structures, (HPhen)2[(UO2)2L2]·4.5H2O (1) and [(UO2)3(H2O)4L2]·6H2O (2), were synthesized using a rigid tripodal linker (4,4',4″-(phenylsilanetriyl)tribenzoic acid, H3L). Compound 1 represents a 2-fold interpenetrating UOF with the unique (10,3)-b topology. Compound 2 is composed of three interlocked sets of identical singlet networks and thus exhibits a rare 3D polythreading network with (3,4)-connected topology. These two compounds have been characterized by IR, UV-vis, and photoluminescent spectroscopy. A density functional theory (DFT) study on the model compounds of 1 and 2 shows good agreement of structural parameters and U═O stretching vibrational frequencies with experimental data. The experimentally measured absorption bands were well reproduced by the time-dependent DFT calculations.

Anionic Metal–Organic Framework for Selective Dye Removal and CO2 Fixation

A microporous Zn‐based anionic metal–organic framework (MOF) was synthesized with triangular 4,4′,4′′‐(pyridine‐2,4,6‐triyl)tribenzoic acid. The anionic MOF material featuring open channels proved to be a good capturing agent for the cationic dye methylene blue. In addition, the Zn‐MOF demonstrated excellent catalytic activity for CO2 fixation by cycloaddition reaction with epoxides for the generation of cyclic carbonates.

A multi-responsive luminescent sensor towards Fe 3+ and acetone based on a Cd-containing metal–organic framework

Abstract A Cd-containing metal–organic framework (CdL), formula as {[Cd3(L)2(H2O)6]·1.5DMF}, has been synthesized under solvothermal condition by the reaction of 4,4′,4″-(methylsilanetriyl)tribenzoic acid (H3L) and Cd2+ ion. Single-crystal X-ray diffraction reveals that CdL displays a three-dimensional framework with 2-fold interpenetration and DMF molecules locate in the void space of the channels. A topological analysis of the framework indicates CdL is a 3,4-connected pto net. The photoluminescence properties of CdL are systematically studied in detail. Impressively, CdL shows excellent detection performance towards Fe3+ ion and acetone in the sensing experiments, which undoubtedly demonstrates the great potential of CdL as a highly selective multi-responsive luminescent sensor for the detection of organic solvents and metal ions.

Structural diversification and single-crystal-to-single-crystal transformation of alkaline earth metal-based MOFs regulated by solvent effect

Two pairs of alkaline earth metal-based MOFs have been synthesized by spontaneous self-assembly reactions of Mg(II) or Ca(II) and two tricarboxylate ligands, H3BTTB and H3TCM (H3BTTB = 4,4′,4′′-[benzene-1,3,5-triyl-tris(oxy)]tribenzoic acid; H3TCM = 4,4′,4′′-{[(2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene)]tris(oxy)}tribenzoic acid), in different solvent media. The Mg/BTTB assemblies, {[Mg3/2(BTTB)(H2O)(DMF)](DMF)}n (1) (DMF = N,N′-dimethylformamide) and {[Mg3/2(BTTB)(DMAc)2](DMAc)0.5}n (2) (DMAc = N,N′-dimethylacetamide), are prepared in DMF/H2O and DMAc/H2O media, respectively, and feature uniform kgd-type 2D bilayer structures but with different compactness. Meanwhile, two Ca/TCM assemblies, {[Ca5/2(TCM)2(DMF)2(H2O)](Me2NH2)(DMF)2(H2O)}n (3) and {[Ca3(TCM)2(DMAc)3(H2O)2](DMAc)5}n (4), have been achieved in DMF/H2O and DMAc/H2O mixed systems as well. However, compounds 3 and 4 have an enormous structural discrepancy, that is, compound 3 shows a complicated parallel 2D → 3D polycatenaned supramolecular architecture while 4 exhibits a 2-fold interpenetrating sit-type 3D framework. These various coordination patterns evidently illustrate the solvent regulation on the alkaline earth metal-based MOFs. The single-crystal-to-single-crystal structural transformation experiment reveals that the loose kgd-network compound 2 can be converted into the compact isoreticular compound 1 when immersed in DMF for 12 h. However, the reversed conversion cannot be realized. In addition, their thermal stability, gas adsorption, and solid-state fluorescence properties have also been investigated.

Topological control of 3,4-connected frameworks based on the Cu2-paddle-wheel node:tboorpto, and why?

Two trigonal tritopic ligands with different conformational degree of freedom: conformationally labile H3tcbpa (tris((4-carboxyl)phenylduryl)amine) and conformationally obstructed H3hmbqa (4,4′,4′′-(4,4,8,8,12,12-hexamethyl-8,12-dihydro-4H-benzo[9,1]quino-lizino[3,4,5,6,7-defg]acridine-2,6,10-triyl)tribenzoic acid) are assembled with square-planar paddle-wheel nodes with the aim of selective engineering of the frameworks with tbo and pto underlying net topologies. In the case of H3tcbpa, both topological types were obtained forming non-interpenetrated MOFs namely DUT-63 (tbo) and DUT-64 (pto). Whereas synthesis of DUT-63 proceeds under typical conditions, formation of DUT-64 requires an additional topology directing reagent (topological modifier). Solvothermal treatment of the conformationally hindered H3hmbqa ligand with the Cu-salt results exclusively in DUT-77 material, based on the single pto net. The possibility to insert the salen based metallated pillar ligand into networks with pto topology post-synthetically results in DUT-78 and DUT-79 materials (both ith-d) and opens new horizons for post-synthetic insertion of catalytically active metals within the above-mentioned topological type of frameworks.

Synthesis, Structures, and Fluorescent Properties of Three Cobalt‐Based Coordination Polymers with a Rigid Tripodal Carboxylate Ligand

AbstractThree cobalt(II) coordination polymers, [Co2(tatb)2(2,2′‐bipy)2 (H2O)2·DMA·2H2O] (1), [Co2(tatb)2(1,10‐phen)2(H2O)2·2H2O] (2) and [Co(tatb)(1,3‐dpp)·H2O] (3) (H3tatb = 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoic acid; 2,2′‐bipy = 2,2′‐bipyridyl; 1,10‐phen = 1,10‐phenanthroline; 1,3‐dpp = 1,3‐bis(pyridin‐4‐yl)propane), were synthesized solvothermally and characterized by single‐crystal and powder X‐ray diffraction (PXRD), as well as IR spectroscopy. Complexes 1 and 2 exhibit 1D double‐chain structures, which further connect into interesting 3D networks by hydrogen bond and strong π–π interactions. Complex 3 possesses 2D 44‐sql topology, which is packed parallel in an AA fashion. Moreover, thermal stability properties and photoluminescence properties of 1, 2 and 3 were also investigated.

Large Tripodal Spacer Ligands for the Construction of Microporous Metal-Organic Frameworks with Diverse Structures and Photocatalytic Activities.

Two microporous complexes, [Zn(TATAB)(OCH3 )]⋅2 H3 O+ (1; TATAB=4,4',4''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)]tribenzoic acid), [Cu1.5 (μ2 -O)TATAB*] (2; TATAB*=4,4'-{[6-(dimethylamino)-1,3,5-triazine-2,4-diyl]bis(azanediyl)}dibenzoic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV absorption spectroscopy, and thermogravimetric analysis, and by powder XRD and single-crystal XRD analysis. Structural analyses revealed that complex 1 possesses a 3D porous framework with uncoordinated water molecules trapped in the pores; the dimensions of the channels are approximately 29.2×12.3 Å2 . Complex 2 has a 3D microporous network structure. In addition, the surface photovoltage and photocatalytic activities were also studied. The photocatalytic properties of the two complexes were investigated by the decomposition of methylene blue under UV and visible-light irradiation. The results revealed that 2 possessea a higher photocatalytic activity than 1 under UV or visible-light irradiation. The potential semiconductor and dye degradation properties of complexes 1 and 2 may be widely applied in the fields of chemical semiconductors and environmental protection in the future.

A luminescent mixed-lanthanide-organic framework sensor for decoding different volatile organic molecules.

A flexible tripodal polyaromatic acid (4,4',4″-(((2,4,6-trimethylbenzene-1,3,5-triyl)-tris(methylene))-tris(oxy))tribenzoic acid, H3TCM) was used to adapt the coordination sites of lanthanide ions for the construction of microporous lanthanide-organic frameworks (LOFs) [LnTCM(H2O)2]·3DMF·H2O (Ln-TCM; Ln = La, Eu, and/or Tb). In these LOFs, the emission band of TCM matches well with the excitation energy of lanthanide ions (Eu(3+) and Tb(3+)) which results in high-efficient resonance energy transfer from TCM to lanthanide ions. Moreover, the mixed EuxTb1-x-TCM has tunable pores to adapt different induced-fit-type host-guest interactions which can modulate both the energy transfer efficiency from TCM to Ln(3+) ions and the energy allocation between Eu(3+) and Tb(3+) ions in the luminescence spectra. We demonstrate that the Eu(x)Tb(1-x)-TCM sensor has the capability of decoding different volatile organic molecules (VOMs) with a clearly differentiable and unique emission intensity ratio of (5)D0 → (7)F2 (Eu(3+), 614 nm) to (5)D4 → (7)F5 (Tb(3+), 545 nm) transitions for every different VOM. Compared with the traditional absolute emission intensity method, such a self-referencing emission intensity strategy has generated self-calibrating, highly differentiable, and very stable luminescent signals for decoding different VOMs from the unique Eu(x)Tb(1-x)-TCM platform, which has great potential for practical applications.

Synthesis and Characterization of Ultraviolet Light-Emitting Organic Acids

Three ultraviolet light-emitting organic acids of 3,3'-(4-phenyl-4H-1,2,4-triazole-3,5-diyl)dibenzoic acid (Tz-1), 4,4',4″-(4H-1,2,4-triazole-3,4,5-triyl)tribenzoic acid (Tz-2), and 4,4'-(4-(4'-carboxy-[1,1'-biphenyl]-4-yl)-4H-1,2,4-triazole-3,5-diyl)dibenzoic acid (Tz-3) were successfully synthesized and fully characterized by the (1)H NMR, the IR absorption spectra, and the X-ray single crystal diffraction. It was found that Tz-1, Tz-2, and Tz-3 could give out the ultraviolet photoluminescent spectra centered at 369 nm, 365 nm and 350 nm, respectively. The luminescence quantum yields of Tz-1 and Tz-2 were measured to be 0.20 and 0.14, respectively. Additionally, the density functional theory (DFT) and the time-dependent DFT calculations were also carried out for Tz-1, Tz-2, and Tz-3.

Three open-framework coordination polymers with new topological structures built on two tripod ligands

By using flexible tricarboxylate 4,4′,4″-(((2,4,6-trimethylbenzene-1,3,5-triyl)tris(methylene))tris(oxy))tribenzoic acid (H3L) and multiimidazole 1,3,5-tri(imidazo-1-ylmethyl)-2,4,6-trimethylbenzene (titb) ligands simultaneously, three novel coordination polymers [M3L2(titb)2]·2H2O·2.5DMF (M=Co,1; Zn, 2; Cd, 3) were synthesized under solvothermal conditions and characterized by single-crystal X-ray diffraction, thermogravimetric and photoluminescent studies. The three compounds are isomorphous and possess a three-dimensional (3D) framework built from 2D sheets of L3− ligands and M ions, and 1D chains of titb ligands and M ions. Topological analyses showed that they exhibit a novel (3,3,4,4) four-nodal 3D net constructed from two 4-connecting metal, and two 3-connecting L3− and titb nodes. Compounds 2 and 3 are photoluminescent upon excitation at room temperature.

Lanthanide homometallic and d–f heterometallic MOFs from the same tripodal ligand: structural comparison, one photon (OP) vs. two photon (TP) luminescence and selective guest adsorption behavior

In this paper, we report the design of a new functionalized tripodal ligand triCB-NTB (4,4′,4′′-(2,2′,2′′-nitrilotris(methylene)tris(1H-benzo[d]imidazole-2,1-diyl)tris(methylene))tribenzoic acid) and its assembly of Eu(III) homometallic or Zn(II)-Eu(III) heterometallic lanthanide-based metal–organic frameworks (MOFs). C3 symmetric Eu(III) center is achieved in the homometallic MOF, [Eu(triCB-NTB)]·DMAc·4H2O (1). The C3 axis of the three coordinated imino N atoms on the propeller-extended central triCB-NTB ligand coincides with the C3 axis that directs the three para-methyl carboxylic benzene arms on three surrounding ligands coordinating with the central Eu(III) simultaneously. Therefore, a (6, 3) pattern is formed in the framework with relatively large porosity. In the Zn-Eu heterometallic framework, [EuZn(triCB-NTB)(H2O)(Cl)2]·2DMAc·H2O (2), the N atoms on the triCB-NTB are coordinated with Zn(II) and the carboxylic O atoms are coordinated with Eu(III). A paddle-wheel linked Eu(III)2 cluster is formed and 1D loop-and-chain structure is obtained. Two ligands, two Zn(II) ions and two Eu(III)2 clusters constitute one box-like unit on the loop chain. Due to the non-inversion symmetry imposed on the central Eu(III) and the large polarizability of the ligand, both one photon (OP) luminescence based on the energy transfer from the ligand to Eu3+ and two photon (TP) luminescence based on the hypersensitive transition of the Eu3+ ions are observed in the two lanthanide-based MOFs. This satisfies the urgent needs of multi-mode luminescent lanthanide complex. Simultaneously, N2 gas and selective vapor adsorptions were also detected in the porous structure of complexes 1 and 2 due to their benzene-filled channels. The six-pointed-star like cavities in 1 can let the gas and vapor molecules go in and out smoothly subject to changes in the pressure, while the narrower and more irregular channels in 2 show irreversible adsorption behavior for benzene and cyclohexane vapor molecules in vacuum under room temperature.

Two chiral Zn(ii) metal–organic frameworks with dinuclear Zn2(COO)3 secondary building units: a 2-D (6,3) net and a 3-D 3-fold interpenetrating (3,5)-connected network

The reaction of Zn(II) and 4,4′,4′′-(benzene-1,3,5-triyl-tris(benzene-4,1-diyl))-tribenzoic acid (H3BBC) without or with the presence of 2-amino-1,4-benzenedicarboxylic acid (NH2-H2BDC) under solvothermal conditions leads to the generation of two novel Zn(II) coordination polymers, [Zn(BBC)(H2O)2](Me2NH2)·12DMF (1) and [Zn2(BBC)(NH2–BDC)](Me2NH2)·10DMF (2), which feature a 2D (6,3) net and a 3D three-fold interpenetrating (3,5)-connected network, respectively. The resulting crystals of 2 were not a racemic mixture but enantiomeric excess, which was confirmed by the measurement of optical rotation of bulk samples using the solid circular dichroism (CD) spectra based on large crystals from one crystallization. Two compounds exhibit strong photoluminescence in the solid state at room temperature.

A porous metal–organic framework (MOF) with unusual 2D→3D polycatenation based on honeycomb layers

A novel mixed-ligand 3D metal-organic framework (MOF), {Zn(2)(TMTA)(bipy)(0.5)(H(2)O)(2)·NO(3)·2DMF·H(2)O}(n) (1) (H(3)TMTA = 4,4',4''-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoic acid, bipy = 4,4'-bipyridine, DMF = dimethylformamide), was constructed based on bipy-pillared honeycomb bilayers and showed the unusual 2D→3D polycatenation of bilayers.

Supramolecular Isomerism in Honeycomb Metal−Organic Frameworks Driven by CH···π Interactions: Homochiral Crystallization from an Achiral Ligand through Chiral Inducement

The solvothermal reaction of Zn(NO(3))(2)·6H(2)O and 4,4',4''-(2,4,6-trimethylbenzene-1,3,5-triyl)tribenzoic acid (H(3)TMTA) in N,N'-diethylformamide or N,N-dimethylacetamide gave rise to two layered honeycomb frameworks. The different stacking arrangements of the 2D layers generate achiral (α-1) and chiral (β-1) architectures, which are supramolecular isomers. The homochiral crystallization of β-1 can be achieved through chiral inducement, which is confirmed by circular dichroism spectra.