2-fold Interpenetration Research Articles

Two Co(II) Isostructural Bifunctional MOFs via Mixed-Ligand Strategy: Syntheses, Crystal Structure, Photocatalytic Degradation of Dyes, and Electrocatalytic Water Oxidation.

The solvothermal reactions involving cobalt ions with 5-methylisophthalic acid (H2MIP) and 1,3-bis(2-methylimidazol)propane (BMIP) yielded two cobalt(II) organic frameworks: {[Co4(MIP)4(BMIP)3]·1/2DMA}n (SNUT-31) and {[Co4(MIP)4(BMIP)3]·(EtOH)2·H2O]}n (SNUT-32) where DMA represents N,N-dimethylacetamide and EtOH signifies ethyl alcohol. Single-crystal X-ray diffraction analyses reveal that SNUT-31 and SNUT-32 possess an isomorphic structure, featuring a unique 2-fold interpenetration of 3D frameworks in a parallel manner. Notably, both SNUT-31 and SNUT-32 demonstrate remarkable performance in electrocatalytic oxygen evolution reactions and exhibit exceptional photocatalytic degradation capabilities against a model comprising three distinct dyes: rhodamine B, methyl orange, and methyl blue.

Fluorescent Tetraphenylethylene-Based Cerium Metal-Organic Frameworks for White-Light-Emitting Diodes.

Discovery of highly efficient and thermal stable phosphors is the focus of the studies in phosphor-converted white light-emitting diodes (LEDs). Herein, a tetraphenylethylene-based cerium metal-organic framework (SYNU-2) was synthesized and characterized. The intricate architecture of SYNU-2 shows an overall 3D → 3D 2-fold interpenetration framework. SYNU-2 exhibited good luminescence properties, and its latent fingerprint developer was prepared, which showed good fluorescence and stability under ultraviolet (UV) radiation. It is worth noting that a prototype WLED device can be designed using SYNU-2 and red phosphors (Ca,Sr)AlSiN3:Eu2+ with CIE coordinates of (0.33, 0.33) at an applied 3 V bias.

Two-Fold Interpenetrated Binuclear Nickel Metal-Organic Framework as a Heterogeneous Catalyst for N-Heterocycle Synthesis.

A binuclear Ni(II)-based metal-organic framework {[Ni2(btb)1.333(H2O)3.578(py)1.422]·(DMF)(H2O)3.25}n (Nibtb) was solvothermally synthesized (H3btb = 1,3,5-tri(4-carboxylphenyl)benzene, py = pyridine, DMF = N,N-dimethylformamide). Nibtb shows a rare 2-fold interpenetrating (3,4)-connected 3D network with a point symbol of (83)4(86)3 based on binuclear Ni(II) clusters. Nibtb as a heterogeneous catalyst combines the high stability of MOFs and excellent catalytic activity of nickel, which exhibits excellent catalytic activity for the synthesis of benzimidazoles and pyrazoles under mild conditions. Moreover, the catalyst can be easily separated and reused for seven successive cycles and maintains high catalytic activity.

Auxiliary linkers-induced assembly of two 2D Co(II)-based coordination polymers with different interpenetrating fashion: Structure and magnetism

The coordination possibilities of rigid aromatic tetracarboxylate ligand with transition metal have been explored. Two new CoII-based coordination polymers with the not fully deprotonated ligand 5,5′-(ethene-1,2-diyl)diisophthalic acid) (H4L) were synthesized and characterized, incorporating different auxiliary ligands, [Co(H2L)(4,4′-bipy)0.5(H2O)]n(1) and {[Co(H2L) (dib)]·2H2O}n(2) (4,4′-bipy = 4,4′-bipyridine, and dib = 1,4-bis(1H-imidazol-1-yl)benzene). The structural analysis related to 1 and 2 illustrated that the auxiliary linkers result in the generation of a fairly 2D (2,3)-connected framework with 4-fold interpenetration for 1 and 2D binodal (2,4)-connected network with 2-fold interpenetration. Magnetic susceptibility measurements demonstrate that 1 and 2 exhibit antiferromagnetic coupling with the corresponding J values of for 1 and 2, respectively.

Synthesis of porous carbon by composing Co-MOF as a precursor for degrading antibiotics in the water

Advanced oxidation process (AOPs) has been widely investigated by environmentalists for treating refractory pollutants in the water. Herein, a new composite Co/CoO/C was successfully synthesized via designing cobalt MOF precursor CUST-591 and carbonized under nitrogen condition. The cobalt based MOF precursor CUST-591 formulated as {[Co2(NTB)(DPE)0.5(H2O)2]}·4H2O·DMA, (NTB = 4,4ˊ,4ˊˊ-nitrilotrisbenzoic, DPE = 1, 2-di (4-pyridyl) ethane, DMA= N, N = dimethylacetamide) exhibits a three-dimensional net (3D) with 2-fold interpenetration. During carbonization, porous carbon obtained from MOF ligands embedded Co nanoparticles to form the porous carbon. The fabricated Co/CoO/C possess great property on degrading tetracycline, oxytetracycline with the activation for peroxymonosulfate (KHSO5, PMS) as a heterogeneous catalyst within 20 min under wide range of pH (3∼7). In addition, catalyst dosage, PMS concentration and pollutant amounts were further investigated to prove the advantages of the catalyst. Radical quenching experiments were conducted to discuss the possible mechanism. The experiment results proved that the reactive oxygen species (ROS) were SO4•- and •OH, especially SO4•− played an important role in the reaction. Meanwhile, the catalyst exhibited excellent stability, and can be easily separated from the water by magnet. This prepared material for PMS activation provided a new prospect to synthesize new compounds based on SR-AOPs.

Contrasting Networks and Entanglements in Uranyl Ion Complexes with Adipic and trans,trans-Muconic Acids.

Adipic (hexane-1,6-dicarboxylic, adpH2) and trans,trans-muconic (trans,trans-hexa-2,4-diene-1,6-dicarboxylic, mucH2) acids have been reacted with uranyl cations under solvo-hydrothermal conditions, yielding nine homo- or heterometallic complexes displaying in their crystal structure the effects of the different flexibility of the ligands. The complexes [PPh4]2[(UO2)2(adp)3] (1) and [Ni(bipy)3][(UO2)2(muc)3]·5H2O (2), where bipy is 2,2'-bipyridine, crystallize as diperiodic networks with the hcb topology, the layers being strongly puckered or quasiplanar, respectively. Whereas [(UO2)2(adp)3Ni(cyclam)]·2H2O (3), where cyclam is 1,4,8,11-tetraazacyclotetradecane, crystallizes as a diperiodic network, [(UO2)2(muc)3Ni(cyclam)]·2H2O (4) is a triperiodic framework in which the NiII cations are introduced as pillars within a uranyl-muc2- framework with the mog topology. [UO2(adp)(HCOO)2Cu(R,S-Me6cyclam)]·2H2O (5), where R,S-Me6cyclam is 7(R),14(S)-5,5,7,12,12,14-hexamethylcyclam, is a diperiodic assembly with the sql topology, and it crystallizes together with [H2NMe2]2[(UO2)2(adp)3] (6), a highly corrugated hcb network with a square-wave profile, which displays 3-fold parallel interpenetration. In contrast, [(UO2)3(muc)2(O)2Cu(R,S-Me6cyclam)] (7) is a diperiodic assembly containing hexanuclear, μ3-oxido-bridged secondary building units which are the nodes of a network with the hxl topology. The two related complexes [PPh3Me]2[(UO2)2(adp)3]·4H2O (8) and [PPh3Me]2[(UO2)2(muc)3]·H2O (9) crystallize as hcb networks, but their different shapes, undulated or quasiplanar, respectively, result in different entanglements, 2-fold parallel interpenetration in 8 and 2-fold inclined 2D → 3D polycatenation in 9.

A new ɛ-Keggin polyoxometalate-based metal-organic framework: From design and synthesis to electrochemical hydrogen evolution

A new ɛ-Keggin polyoxometalate based metal-organic framework, [TBA]3[H4PMo8VMo4VIO40Zn4](HTPT)2 (1) (H3TPT = 1,1′:4′,1″-terphenyl-3,4″,5-tricarboxylic acid, TBA+ = tetrabutylammonium ion) was synthesized under hydrothermal conditions. The tetrahedral Zn4-ε-Keggin is connected through angular HTPT2− to form a 2D entangled structure with 2-fold interpenetration. The whole network displays a staggered layer structure in AB/CD/EF/GH/AB/CD/EF/GH arrangement with extensive hydrogen bonding and intermolecular interactions. More interestingly, compound 1 exhibited good hydrogen evolution reaction (HER) activity in an acidic medium, with a Tafel slope of 68 mV·dec−1 and an η10 of 417 mV. It showed an excellent long-term stability, which could maintain its catalytic activity after 1000 cycles.

The Structure and Property of Two Different Metal-Organic Frameworks Based on N/O-Donor Mixed Ligands

Two different metal-organic frameworks (MOFs) [Cd2(AZN)(HAZN)(btc)(Hbtc)·4H2O]·2H2O (1), and [Zn3(AZN)2(btc)2·4H2O] (2) were synthesized by the reactions of different metal salts with mixed ligands of 1-(4-(1H-imidazol-5-yl)phenyl)-1H-1,2,4-triazole (AZN) and trimesic acid (H3btc). The different metal centers in the reaction condition have important impact on the resulting structures of MOFs 1 and 2. Compound 1 is a one-dimensional (1D) chain structure, while 2 features a three-dimensional (3D) framework with 3-fold interpenetration topology of Point (Schläfli) symbol of (6·82)4(62·82·102). Furthermore, the luminescent properties have been studied for MOFs 1 and 2.

Multi-responsive fluorescent sensor based on Cu(II) coordination polymer for selective detection of acetylacetone and Cr(VI) ions

A novel Cu(II) coordination polymer [Cu(HL)(4,4′-bpy)]n (4,4′-bpy = 4,4′-bipyridine) 1 based on a semi-rigid tricarboxylate, 5-(3,4-dicarboxylphenoxy) nicotinic acid (H3L) has been hydrothermally synthesized. Single-crystal X-ray diffraction analysis indicates that, in compound 1, H3L ligands first extend the metal ions into a 2-D layer. Then the 4,4′-bpy molecules functioned as bidentate bridge, strutting the 2-D layers into a 3-D open network with a (63) (69·8) topology. Notably, 1-D channels of ca. 6.5 × 10.5 Å2 are observed in 1, but due to 2-fold interpenetration phenomenon, these channels become small or disappear. Fluorescent spectra indicate 1 can act as a muti-chemosensor for detection of acetylacetone (Hacac), Cr2O72− and CrO42− in aqueous solution with high selectivity and sensitivity. The mechanism of luminescent sensing Hacac and Cr(VI) were also investigated in detail.

Syntheses, structures and properties of two Ni(II) coordination polymers based on an anionic ligand deprotonated 5-((3-carboxyphenoxy)methyl)benzene-1,3-dioic acid and different neutral ligands

Two Ni(II)-based coordination polymers, [Ni1.5(L)(dib)1.5(H2O)]·2H2O (1) and [Ni1.5(L)(bimb)1.5(H2O)2]·4H2O (2), were synthesized by using the same anionic ligand and different neutral ligands under the same hydrothermal conditions. The structures of these two coordination polymers were determined by single-crystal X-ray crystallography. Compound 1 reveals a 2D net which is extended to be a 3D supramolecular framework with intermolecular π-π interactions. Compound 2 shows a 2-fold interpenetrating (3,4,4)-connected framework with {63}2{62·84}{64·82}2 topology. The results confirm that organic ligands play an important role in the assembly of various coordination polymers. Elemental analyses, infrared spectra, powder X-ray diffraction and UV–vis absorption spectra were measured, and magnetic properties were also studied.

A novel 3D cobalt(II) metal–organic framework to activate peroxymonosulfate for degradation of organic dyes in water

A novel cobalt(II) metal-organic framework, formulated as {[Co3(NTB)2(DPE)(DMF)]}·7H2O·3DMF (1) (NTB ​= ​4,4ˊ,4ˊˊ-nitrilotrisbenzoic, DPE ​= ​1,2-di(4-pyridyl)ethane, DMF ​= ​N,N-dimethylformamide) has been successfully synthesized via solvothermal conditions. This metal-organic framework (MOF) has a three-dimensional (3D) net with 2-fold interpenetration. It can be acted as a heterogenous catalyst to activate peroxymonosulfate (PMS) to generate sulfate radicals (SO4•−) to degrade organic dyes in water, such as Rhodamine B (RhB), Methyl orange (MO) and Methylene blue (MB) with the degradation efficiency is all above 93%. For RhB degradation, the possible mechanism and factors affecting the PMS activation were investigated in detail. Additionally, 1 also exhibits excellent chemical stability and stable catalytic activity.

Two new Zn2+/Cd2+ Metal-Organic Frameworks (MOFs) constructed from asymmetrical tricarboxylic acid ligands

Two new Metal-Organic Frameworks (MOFs), namely, [Cd(HL1)(H2O)] 1, [H2(bpp)][Zn2(L2)2(bpe)]·2H2O 2 (H3L1 = 4-(5-carboxy-pyridine-3-yloxy)-phthalic acid, H3L2 = 3-(4-carboxy-phenoxy)-phthalic acid, bpe = 1,2-bis(4-pyridyl) ethylene, bpp = 1,3-bis(4-piperidyl) propane) have been isolated employing two V-shaped asymmetric tricarboxylic acid ligands under hydrothermal conditions. X-ray single-crystal diffraction analysis reveals that μ4-mode HL12− molecules propagate the Cd2+ centers into a 3-D network with point symbol of 66 for 1. One-dimensional channels are observed in 1, but because of 2-fold interpenetration phenomenon, these channels become small or disappear. 2 possesses a 2-D layered structure with (3, 4)-connected (42ˑ63ˑ8) (42ˑ6) topology. The carboxyl moieties for L2 molecules first extend the Zn2+ centers into a 1-D double chain, then via the interactions between Zn2+ and pyridine N atoms, the resulting 1-D double chain are strutted by the rigid bpe ligands to form a 2-D layer framework. It is noteworthy that one-dimensional channels of ca. 13 × 13 Å2 are observed. H2(bpp)2+ and two lattice water molecules occupy the space of the channels. The introduced bpp molecules only serve as the templating agent and are not involved in the formation of this layer network. The photoluminescence properties of 1 and 2 were investigated.

Two novel 3D MOFs based on the flexible (E)-1,4-di(1H-imidazol-1-yl)but-2-ene and multi-carboxylate ligands: Synthesis, structural diversity and luminescence property

Two novel metal-organic frameworks [Zn(btec)0.5(dib)]·H2O (1) (H4btec = benzene-1,2,4,5-tetracarboxylic acid, dib = (E)-1,4-di(1H-imidazol-1-yl)but-2-ene) and [Cd(btc)(dib)]·(C2H6N) (2) (H3btc = benzene-1,3,5-tricarboxylic acid) have been synthesized under solvothermal conditions. Complexes 1 and 2 were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and thermogravimetric analysis (TGA). Crystal structure analysis reveals that complex 1 is a complicated three-dimensional (3D) non-interpenetrated porous framework, while complex 2 displays a 2-fold interpenetration 3D framework. The solid state photoluminescent properties of complexes 1–2 were recorded and discussed.

Modular construction, magnetism and photocatalytic properties of two new metal-organic frameworks based on a semi-rigid tetracarboxylate ligand

The solvothermal reactions of 5,5ˊ-(1,4-phenylenebis(methyleneoxy))diisophthalic acid (H4L) with cobalt(II) salts in presence of two N-donor ancillary ligands yielded two new metal–organic frameworks (MOFs) viz., [Co2(L)(bpz)(H2O)]n (bpz = 3,3′,5,5′-tetramethyl-4,4′-bipyrazole) (1) and [Co2(μ2-H2O)(H2L)2(tib)2·2CH3CN·2H2O]n (tib = 1,3,5-tris(1-imida-zolyl) benzene) (2). The single-crystal X-ray diffraction studies revealed that 1 displays 3,6-connected 3-periodic network with 2-fold interpenetration feature while 2 exhibits only 1D chain structure. The nature of ancillary ligands and the influence of N-donor ligands on coordination framework of these compounds have been discussed. The photocatalytic activities of these newly designed MOFs have been tested for the degradation of methyl violet (MV). The results of photocatalytic experiments demonstrated that both 1 and 2 displayed efficient photocatalytic performances to degrade MV under UV irradiation. The plausible mechanism through which both the MOFs displayed photocatalytic properties have been proposed through density of states (DOS) calculations. Also, the magnetic properties of both the MOFs have been analysed in detail which indicated χMT values of 6.02 and 6.54 cm3 K mol−1 for 1 and 2, respectively at 300 K which declined to 3.64 cm3 K mol−1 for 1 and 0.34 cm3 K mol−1 for 2 at 2 K.

Dynamics of Water Molecules in a 3-Fold Interpenetrated Hydrogen-Bonded Organic Framework Based on Tetrakis(4-pyridyl)methane

The 3-fold interpenetration of the β-quartz-type hydrogen-bonded organic framework (HOF) from the dication salts of tetrakis(4-pyridyl)methane develops a host–guest system featuring flexibility and durability in accordance with the state change of guest molecules. Water molecules are incorporated into HOF and form a one-dimensional helical-shaped molecular chain in nanopores. X-ray crystallographic analysis and the dielectric dispersion in the impedance measurements revealed that guest water molecules behave dynamically and show a concerted freezing process to produce water pentamers at 100 K. Structural changes in the host framework mediate interactions between guest water molecules within and between the nanopores through the weak host–guest interactions based on hydrogen-bonding interaction. In addition, the triangular arrangement of nanopores gives rise to the topologically unsettled guest molecules in the freezing process.

Two 3D Co(II) coordination polymers modulated by rigid tris(imidazolyl) ligands: Syntheses, structural diversity and photo-degradation properties

Two novel coordination polymers (CPs) based on cobalt transition metal, namely {[Co(tib)2]·2HNO3}n (1) and {[Co(tib)(4,4′-sbdc)]·H2O}n (2) (tib = 1,3,5-tris(1-imidazolyl)benzene, H2sbdc = 4,4′-stilbenedicarboxylic), have been designed and successfully synthesized under solvothermal conditions, which were characterized by elemental analysis, infrared spectra, powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that complex 1 features a stable 2D → 3D supramolecular frameworks through H-bonds with a rare (3,6)-connected kgd topology and complex 2 displays a 2-fold interpenetrating (2,4)-connected new topology with the point Schläfli of (44·62)(42). Importantly, the photo-catalytic properties of complexes 1–2 have been investigated, and then complex 2 is a good photo-catalyst for the degradation of mixed organic dyes (MB/MV/RhB).

Coordination polymers from bent ligands or how to obtain rare topologies with simple linkers and nodes

Abstract Five Zn(II)/Cd(II) coordination polymers, namely, [Cd2(bdc)2(bmis)2] (1), [Cd2(bpdc)2(bmis)2] (2), [Cd3(btb)2(bmis)2]·5DMF (3), [Zn2(2,6-ndc)2(bmis)2] (4) and [Zn(sdc)(bmis)]2·3H2O (5) {bmis = bis(4-(2′-methylimidazol)phenyl)sulfone, H2bdc = 1,4-benzenedicaroboxylic acid, 2,6-H2ndc = naphthalene-2,6-dicarboxylic acid, H2sdc = 4,4′-sulfonyldibenzoic acid, H2bpdc = biphenyl-4,4′-dicarboxylic acid and H3btb = 4,4′,4′’-benzene-1,3,5-triyl-tribenzoic acid} have been synthesized and structurally characterized. Compound 1 features a rare self-catenated motif 4T19 with high topological density (TD10 = 2318) and very complicated ring-catenations. Compound 2 presents an unusual highly catenated mode of 4-fold interpenetration of dia networks. Compound 3 shows a first example of parallel polycatenation for highly coordinated 2D 3,10L3 nets. Compound 4 exhibits a rare type of 3-fold interpenetration of dia networks. Compound 5 shows a typical pattern of parallel polycatenation of sql networks. In addition, thermal stability and optical properties have been studied in detail for the five synthesized compounds.

Interpenetration-Dependent Luminescent Probe in Indium-Organic Frameworks for Selectively Detecting Nitrofurazone in Water.

Two novel anionic In-MOFs V101 and V102 were synthesized and structurally characterized. The structrual transformation from 2-fold interpenetration to noninterpenetration was completed by changing solvent from DMF to DEF. Luminescence investigations reveal that only V102 not V101 can sensitively and selectively detect traces of antibiotics nitrofurazone in water solution via an environmentally friendly manner, and the detection limit can reach to 0.2 ppm. The luminescent difference between V101 and V102 mainly originates from the divergence of interpenetration structures. Namely, through interpenetration-control, the luminescent probe can switch on or off to detect nitrofurazone. This is the first example of interpenetration-dependent MOFs-based luminescent probe.

Structural Diversity and Vibrational Spectra of Nine Cu(I)-Cyanide Metal–Organic Frameworks with in Situ Generated N-Heterocyclic Ligands

Nine Cu(I)-cyanide metal–organic frameworks (MOFs), namely, [Cu4(CN)2(4-bpt)2]n (1), {[Cu3(CN)2(4-bpt)]·H2O}n (2), [Cu2(CN)(3-bpt)]n (3), [Cu2(CN)2(3-Hptz)]n (4), [Cu3(CN)2(3-ptz)]n (5), [Cu7(CN)7(3-tpt)2]n (6), {[Cu9(CN)9(btb)2]·btb}n (7), [Cu2(CN)2(4-azpy)]n (8), and [Cu3(CN)3(bpp)]n (9) (4/3-Hbpt = 3,5-bis(4/3-pyridyl)-1,2,4-triazole; 3-Hptz = 3-pyridyl-tetrazole; 3-tpt = 2,4,6-tris(3-pyridyl)-1,3,5-triazine; btb = 1,4-bis(1,2,4-triazol-4-yl)benzene; 4-azpy = 4,4′-azobispyridine; bpp = 1,3-bis(4-pyridyl)propane), were synthesized under hydrothermal conditions and structurally characterized. The 4-bpt, 3-bpt, and 3-Hptz ligands in 1–4 were in situ generated by cycloaddition reactions. Their structural features vary from two-dimensional (2D) (3), three-dimensional (3D) (4, 5, 6), 3D 2-fold interpenetration (1, 2, 8), to 3D 3-fold interpenetration (7, 9). Complex 1 is an intriguing 3D metal–organic framework (MOF) with a nanosized rectangular channel. Complex 3 exhibits a chiral 2D double-layered network ...

Structural diversity of three entangled metal-organic frameworks from a bisimidazole ligand and dicarboxylic acids with varied length

Based on a bisimidazole ligand and dicarboxylic acids with varied length, three entangled metal-organic frameworks have been synthesized and structurally characterized. Compound 1 shows a 4-fold interpenetration of dia net. Compound 2 presents an unusual 1D→3D polycatenane by the 4-fold interpenetration of 1D tubular net. Compound 3 exhibits a 3-fold interpenetration of pcu net. Their luminescent properties were also investigated.