Point Symbol Research Articles

Three coordination networks of Cd(II) with 2-hydroxy-trimesic acid and their photoluminescence properties

With a rigid carboxylic acid ligand, 2-hydroxy-trimesic acid (H4L), coordination polymers {[Cd3(L)2(H2O)6]·4H2O}n (1), [Cd2(H2L)2(pdp)0.5(µ-H2O)]n(2) azobispridine (pdp) and [Cd(4,4ʹ-bipy)2(H2O)2]n·[H2L]n (3) 4,4’-bipyridine (4,4’-bipy) were synthesized. Compound 1 is a three-dimensional network of linear trinuclear clusters [Cd3(μ2-COO)2(μ1-COO)2]. Compound 2 can be simplified as a 3.12-connected 3-nodal net with a new topological point symbol of {4.52}4{416.516.626.88}. Compound 3 features a two-dimensional grid cationic architecture with rectangle channels encapsulating [H2L]2− anions. The powder X-ray diffraction, the thermal stabilities, and solid-state luminescence properties were studied for 1–3. Furthermore, compound 1 shows high selectivity and sensitivity for detecting both NB and Fe3+.

Synthesis, Thermal Stability and Magnetic Properties of an Interpenetrated Mn(II) Triazolate Coordination Framework

AbstractCoordination frameworks and metal‐organic frameworks built from simple triazole ligands such as 1H‐1,2,3‐triazole (H‐ta) have recently inspired great interest owing to physical phenomena such as electronic conductivity, phase transitions and their magnetic behavior. In line of our endeavors we report on the solvothermal reaction of MnCl2 ⋅ 4H2O with H‐ta ligand in isopropyl alcohol leading to the the novel CFA‐23 (((propan‐2‐yl)oxidanium)+[Mn6Cl5(ta)8]−; CFA‐23=Coordination Framework Augsburg University‐23) coordination framework. Single‐crystal X‐ray diffraction (SC‐XRD) reveals that it crystallizes in the tetragonal space group P42/nnm (134) exhibiting a two‐fold interpenetrated framework with the topologies of a dia net with point (Schläfli) symbol 66. The thermal stability of this compound was investigated using variable temperature X‐ray powder diffraction and thermogravimetric analysis. The magnetic properties of CFA‐23 differ from a similar non‐interpenetrated literature structure of the composition (H[Mn6(bta)8Cl5] ⋅ (H2O)4) built from 1H‐1,2,3‐benzotriazole, thus, indicating that sterically induced lattice changes might be an adjustment parameter for magnetic properties in such frameworks.

A new two-dimensional cadmium(II) coordination polymer based on Cd6(CHADC)6 clusters (H2CHADC is cyclohexane-1,2-dicarboxylic acid): synthesis, structure and properties.

The highly effective recognition and detection of metal ions and anions in water has attracted much attention with respect to environmental safety. Herein, a novel Cd-based coordination polymer, poly[[4,4'-bis(2-methylimidazol-1-yl)biphenyl]bis(cyclohexane-1,2-dicarboxylato)dicadmium(II)], [Cd2(C8H10O4)2(C20H18N4)]n or [Cd(CHADC)(4,4'-BMIBP)0.5]n, (I), has been synthesized employing cis-cyclohexane-1,2-dicarboxylic acid (H2CHADC) and 4,4'-bis(2-methyl-1H-imidazol-1-yl)biphenyl (4,4'-BMIBP). Single-crystal X-ray analysis reveals that (I) presents a 6-connected hxl two-dimensional layer based on Cd6(CHADC)6 clusters with the point symbol (36·46·53). Furthermore, (I) has been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and fluorescence spectroscopy, and exhibits good stability and excellent photoluminescence properties. Coordination polymer (I) was chosen as a fluorescent probe to sense different target analytes and shows an obvious selective recognition response to Fe3+ cations and Cr2O72-/CrO42- anions through luminescence-quenching effects in aqueous solution. The sensing mechanism was investigated and showed that the detection mechanism was resonance energy transfer between (I) and the Fe3+, Cr2O72- and CrO42- ions.

Semiconductive MOFs with tetranuclear Co-clusters constructed from 2,5-dimethoxyterephthalic acid and phenyl imidazole ligands

Complexes {[Co2(DTA)2(1,4-BMIB)(H2O)]·1·.5H2O}n(ZNC-9) and {[Co2 (DTA)1.5(OH)(TIB)]·5H2O}n (ZNC-10) (H2DTA = 2,5-dimethoxyterephthalic acid, 1,4-BMIB = 1,4-bis(2-methyl-1H-imidazol-1-yl)benzene, TIB = 1,3,5-tri(1H- imidazol-1-yl)benzene) were obtained via hydrothermal reaction condition. DTA2− ligands adopted various coordination modes to result in tetranuclear clusters [Co4(CO2)8(μ2-H2O)2] and [Co4(μ3-OH)2]6+ in ZNC-9 and ZNC-10, respectively. In complex ZNC-9, [Co4(CO2)8(μ2-H2O)2] as 10-connected node was bridged by DTA2− and 1,4-BMIB to form a 3D framework with Schlafli symbol of (36.434.62). In complex ZNC-10, DTA2− ligands and [Co4(μ3-OH)2]2+ built a 4-connected dia net, while TIB and [Co4(μ3-OH)2] units built a 3,6-connected ant net. The dia and ant nets further constructed a (3,10)-connected framework with point symbol (3.42)2(34.410.512.613.76). Additionally, UV–vis spectra and electrochemical tests have confirmed that ZNC-9 and ZNC-10 belong to n-type semiconductors possessing low resistance for charge transportation. In photo-catalytic experiments, ZNC-9 and ZNC-10 have obvious catalytic activity in degradation of dye under ultraviolet light.

Photocatalytic applications of a new 3D Mn(II)-based MOF with mab topology

A new 3D metal–organic framework (MOF) with formula [Mn4(NDC)2(bb)4] (1) (H2NDC = 1,4-naphthalenedicarboxylic acid and bb = 4,4′- bis(imidazolyl) biphenyl), has been prepared and characterized using FTIR spectroscopy and single crystal X-ray. The single crystal X-ray analysis reveals that 1 comprises of 6-connected mab-type network with (44.610.8) point symbol. The photocatalytic properties of 1 to photodegrade aromatic dyes reveals that it could effectively photodegrade dyes viz. Rhodamine B (Rh B), Chrome Blue (CB), and methylene blue (MB). Moreover, the active species involved in the degradation of Rh B has been assessed using trapping experiments and band gap calculation has been performed to establish the plausible photocatalytic mechanism.

Two dual functional 3D Cd-based coordination polymers for the highly luminescent sensitive detection of Fe3+ and norfloxacin

Two new Cd(II) coordination polymers(CPs) [Cd2.5(L1)(Htbip)(tbip)2]n (1) and {[Cd(L2)0.5(1,4-chdc)]·H2O}n (2) (L1 ​= ​1,2-bis(2-ethylbenzimidazol-1-ylmethyl)benzene, L2 ​= ​1,4-bis(2-ethylbenzimidazol-1-ylmethyl)benzene, H2tbip ​= ​5-tert-butylisophthalic acid; 1,4-H2chdc ​= ​1,4-cyclohexanedioic acid) were hydrothermal synthesized and structural characterized. 1 can be defined as a 3D 6,8T13 network with the point symbol of {32.410.52.6}{34.412.58.64}. 2 reveals an unusual 3D xww-3,4-P21/c topological frameworks with the point symbol of {4.82.103}{4.82}. Both CPs possessed highly thermal and chemical stability. 1 and 2 can be as bifunctional luminescent sensors for effective detection of Fe3+ and norfloxacin.

Three Cd-MOFs with water stability act as novel fluorescent probes for detecting nitrofuran, nitrofurantoin and Fe3+

Three new metal-organic frameworks (MOFs): [Cd3(NTB)2(DPE)]·H2O (CUST-555), [Cd3(NTB)2(BIMB)]·H2O (CUST-556) and Cd3O(NTB)2(DPE) (CUST-557), (H3NTB ​= ​4,4ˊ,4ˊˊ-nitrilotrisbenzoic acid; DPE ​= ​1,3-di(4-pyridyl)ethane; BIMB ​= ​1,4-bis((1H-imidazole-1-yl)methyl)benzene), were obtained by solvothermal method. Single-crystal X-ray diffraction analyses revealed that CUST-555 and CUST-556 both crystallized in the monoclinic system with C2/c space group, while CUST-557 was in the trigonal system with P31 space group. The topological analysis showed that CUST-555 and CUST-556 had the same topology and were based on 3,8-connected net with the point symbol {43·624·8}{43}2, while CUST-557 was based on 3,8-connected net with the point symbol {43}2{46·618·84}. Luminescence studies show that CUST-555, CUST-556 and CUST-557 display highly sensitive, selective, and recyclable properties in the detection of ferric ion and nitrofuran antibiotics such as nitrofurantoin (NFT) and nitrofurazone (NZF). In addition, the possible fluorescence quenching mechanism were explored.

Spatiotemporal Visualisation of PS InSAR Generated Space–Time Series Describing Large Areal Land Deformations Using Diagram Map with Spiral Graph

The space–time series carry information on temporal and spatial patterns in observed phenomena. The reported research integrates computational, visual and cartographic methods to support visual analysis of space–time series describing terrain surface movement. The proposed methodology for space–time series visualisation can support their analysts in investigating space–time patterns using transformation, clustering, filtration and visualisation. The presented approach involves spiral graphs for representation time dimension and cartographic visualisation through proportional point symbol map for representation of spatial dimension. The result is an intuitive visualisation of space–time series, conveying the sought-after spatio-temporal information. For practical tests, we used space–time series obtained by permanent scatterers interferometry (PS InSAR) to monitor the Earth’s surface movement above the underground gas storage (UGS) Tvrdonice, the Czech Republic. An UGS is characterised by periodic injection and withdrawal of natural gas, which induces periodic movement of the terrain above it. We have verified that our visualisation method provides the required pattern information and is easy to use.

Metal-Organic Framework-Based Selective Molecular Recognition of Organic Amines and Fixation of CO2 into Cyclic Carbonates.

Synthesis and structural depiction of two new metal-organic frameworks (MOFs), namely, [{Zn(L)(oba)}·4H2O]α (Zn-MOF-1) and [{Cd1/2(L)1/2(nipa)1/2(H2O)1/2}·(DMF)1/2(H2O)]α (Cd-MOF-2) (where L = N2,N6-di(pyridin-4-yl)naphthalene-2,6-dicarboxamide, 4,4'-H2oba = 4,4'-oxybisbenzoic acid, and 5-H2nipa = 5-nitroisophthalic acid) are reported. Both Zn-MOF-1 and Cd-MOF-2 have been prepared by reacting ligand L and coligand 4,4'-H2oba or 5-H2nipa with the respective dihydrates of Zn(OAc)2 and Cd(OAc)2 (OAc = acetate). Crystal structure X-ray analysis discloses that Zn-MOF-1 displays an overall 2D → 3D interpenetrated framework structure. The topological analysis by ToposPro suggests a (4)-connected uninodal sql topology with a point symbol of {44·62} having 2D + 2D parallel polycatenation. However, crystal packing of Cd-MOF-2 adapted a porous framework architecture and was topologically simplified as (3,4)-connected binodal 2D net. In addition, both Zn-MOF-1 and Cd-MOF-2 were proved to be multifunctional materials for the recognition of organic amines and in the fixation of CO2 to cyclic carbonates. Remarkably, Zn-MOF-1 and Cd-MOF-2 showed very good fluorescence stability in aqueous media and have shown 98 and 97% quenching efficiencies, respectively, for 4-aminobenzoic acid (4-ABA), among all of the researched amines. The mechanistic study of organic amines recognition proposed that fluorescence quenching happened mainly through hydrogen-bonding and π-π stacking interactions. Additionally, cycloaddition of CO2 to epoxide in the presence of Zn-MOF-1 and Cd-MOF-2 afforded up to 96% of cyclic carbonate within 24 h. Both Zn-MOF-1 and Cd-MOF-2 exhibited recyclability for up to five cycles without noticing an appreciable loss in their sensing or catalytic efficiency.

Two transition metal-organic frameworks based on 5-phenyl-isophthalate and N-donor mixed ligands: Structure, magnetic, drug delivery and catalytic properties

Two transition metal-based MOFs, {[Ni2(pip)2(bimb)1.5]·2(H2O)}n (1), and {[Zn(pip)(bimb)]·DMF}n (2) (pip ​= ​5-phenyl-isophthalate, bimb ​= ​1,4-bis(imidazole-1-ylmethyl)benzene) have been successfully prepared. Complex 1 displays a three-dimensional structure with a 7-connected svk topology with a point symbol of (33∙414∙53∙6). Complex 2 performs a two-dimensional (4,4) sql net with channels of 7.0 ​× ​5.5 ​Å2 and 10.5 ​× ​4.7 ​Å2 along the b and c axis, respectively. The magnetic result of 1 shows an antiferromagnetic coupling between the two metal centers. Desolvated 2 adsorbs around 15.25 ​wt% 5-fluorouracil (5-FU). The 5-FU was slowly released without any burst release. The degradation of methyl orange caused by oxidizing sulfate radicals (SO4−) in a Fenton-like process has also been explored.

Four Cd(II)–based metal organic frameworks: Syntheses, structures and fluorescent probes for highly selective, sensitive detection for nitrobenzene

Four Cd-MOFs named [Cd(casb)(bimb)]n (1), {[Cd3(t-4-cpp)2(btadpe)2(H2O)2]·4(H2O)}n (2), [Cd(tpa)(tib)]n (3), [Cd2(t-3-cpp)2(bimb)]n (4), were succes-sfully constructed under the condition of solvothermal (H2casb ​= ​4-((carboxylatoethyl)sulfanyl)benzoic acid, H3(t-4-cpp) ​= ​2,4,6-tri(4-carboxylphenyl)pyridine, H2tpa ​= ​terephthalic acid, H3(t-3-cpp) ​= ​2,4,6-tri(4-carboxylphenyl)pyridine, bimb ​= ​1,4-bis(imidazole-1-ylmethyl)benzene, btadpe ​= ​4,4′-bis(4H-1,2,4-triazol-4-yl)diphenyl ether, tib ​= ​1,3,5-tirs(1-imidazolyl)benzene). Four complexes were characterized by X-ray single-crystal diffraction, elemental analysis, IR spectra. 1 exhibits a two-dimensional (2D) framework with three-fold interpenetrating architecture featuring an uninodal 4-connected network with point symbol of {44·62}. 2 features a three-dimensional (3D) network sructure. 3 shows a 3D two-fold interpenetrating architecture framework featuring a 2-nodal (3,5)-connected network with point symbol of {42·65·83}{42·6}. 4 has a 2D two-fold interpenetrating architecture featuring a 2-nodal (3,4)-connected network with point symbol of {42·63·8}{42·6}. Furthermore, the fluorescence quenching experimental results showed that 1–4 exhibits selective fluorescence sensing nitrobenzene (NB). The concentration-fluorescence experimental result shows that the detection limit of 2–4 for NB is 5.74 ​× ​10−7 ​M, 2.80 ​× ​10−7 ​M and 3.25 ​× ​10−7 ​M based on 3σ/Ksv, respectively.

Highly stable supercapacitive performance of a (3, 4, 6‐c)‐connected 2D Co‐MOF

AbstractTwo‐dimensional (2D) metal–organic frameworks (MOFs) used directly in supercapacitors have been a worldwide research interest for their potential high performance. Herein, one new 2D Co‐based MOF, [CoCo0.5Co0.5(μ–ppa)2(H2O)3]n, namely, (BBU‐1), has been synthesized through solvothermal method with the ligand H2ppa (H2ppa = 3‐(pyrazin‐2‐yl)‐1H‐pyrazole‐5‐carboxylic acid). Single X‐ray diffraction analysis shows that the BBU‐1 exhibits a (3, 4, 6‐c)‐connected 2D structure bridged through the carboxylic group, with the topological point symbol of {3·4·5}2{32·42·52·62·74·82·9}{32·62·72}. PXRD Rietveld refinement also has been employed to confirm the structure. The Co‐MOF electrode showed a high specific capacitance and a good cycling stability. Its maximum specific capacitance was 134.5 F g−1 at 3 mV s−1, and the specific capacitance retention is about 91.3% after 1000 cycles at a current density of 2 A g−1 in the 2‐M KOH solution. These results show that the pristine 2D Co‐MOF is an excellent candidate of electrode active material for electrochemical energy storage.

A series of coordination polymers constructed by 2-phenylsuccinic acid and flexible bis(imidazole) ligands: Syntheses, structures, and photoluminescent properties

Eight coordination polymers (CPs), namely, [Co(μ-phsuc)(μ-obix)]n(1), {[Co2(μ-phsuc)2(μ-pbix)1.5]⋅2H2O}n(2), [Zn(μ-phsuc)(μ-obix)]n(3), {[Zn(μ-phsuc)(μ-mbix)]⋅H2O}n(4), {[Zn(μ-phsuc)(μ-pbix)]⋅H2O}n(5), {[Zn(μ-phsuc)(μ-pbix)]⋅1.5H2O⋅CH3OH}n(6), [Cd(μ-phsuc)(μ-obix)]n(7) and [Cd(μ3-phsuc)(μ-pbix)0.5]n(8) (phsucH2 = 2-phenylsuccinic acid, obix = 1,2-bis((imidazol-1-yl)methyl)benzene, mbix = 1,3-bis((imidazol-1-yl)methyl)benzene, pbix = 1,4-bis((imidazol-1-yl)methyl)benzene), were solvothermally synthesized and characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermal analyses. The structural analyses revealed that the compounds were 2D coordination polymers, in which metal ions were in tetrahedral coordination geometries in 1-6 and in octahedral coordination geometries in 2, 7 and 8. Compounds 1, 3, 4, 5, 7 and 8 displayed 4-connected 2D wave sheets with the point symbol of {44.62}. Compound 2 was rare example exhibiting a 2D polyrotaxane structure. Compound 6 showed a two-fold interpenetrated 2D structure with hcb topology (the point symbol of {63}). In the compounds, the neighboring 2D layers were further assembled by π⋅⋅⋅π stacking and weak C–H⋅⋅⋅π interactions into the 3D supramolecular framework. The effects of the bis(imidazole) linkers and metals ions on the framework assemblies have been discussed. In addition, thermal and photoluminescent and optical properties of the compounds were investigated.

Two new isotypic Co(II)/Ni(II)-coordination polymers based on 5-(6-Carboxypyridin-2-yl)isophthalic acid: Synthesis, structure analysis and magnetism properties

Two new two-dimensional (2D) metal-organic frameworks (MOFs), named [Co3(L)2(H2O)4] (1) and [Ni3(L)2(H2O)4] (2) [H3L = 5-(6-Carboxypyridin-2-yl)isophthalic acid], have been solvothermally synthesized under different solvent systems, which have been well characterized by elemental analysis, FT-IR spectrum, powder X-ray diffraction (PXRD) and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction shows that 1 and 2 are isomorphic structures, giving a 2D layer structure based on the trinuclear secondary building units (SBU). Topology analyses reveal that 1 and 2 can be simplified as a binodal (3, 6)-connected kgd topological net with the point symbol (43)(46·66·83). The magnetic properties for 1 and 2 have been systemically explored, which shows the antiferromagnetic interactions between metal ions in the solid state.

A stable zinc-based metal–organic framework as fluorescent sensor for detecting Cr2O72−, Fe3+ and L-Cysteine with high sensitivity and selectivity

In this report, a novel metal–organic framework [Zn(BMTH)]n(1) (H2BMTH = 5,6-benzimidazole diacylhydrazide) based on the coordination of acylhydrazide ligand and Zn2+ was synthesized, in which the H2BMTH ligand was generated via in situ acylation reaction between benzimidazole-5,6-dicarboxylic acid and N2H4. X-ray single-crystal diffraction analyses indicate that compound 1 displays a three-dimensional (3-D) network with the point (Schläfli) symbol of (42⋅63⋅8), where a parallelogram channel with the size of 11.63 × 10.59 Å2 is observed. Furthermore, 1 is a promising luminescent sensor for detecting Cr2O72− and Fe3+. Note that Fe3+ solution was incorporated into compound 1 to construct the new sensor, Fe3+@1. As expected, Fe3+@1 can sense L-Cysteine (L-Cys) selectively, which can be designed as a novel “turn-on” fluorescence sensor of L-Cys. The study of fluorescence performance indicates that in the range of 0–25 µM for L-Cys, the variation of the proposed approach exhibits a good linear relationship with corresponding detection limits of 0.892 µM.

Anthracene‐Modified Cadmium Metal‐Organic Framework as an Excellent Sensor for the Detection of 2,4,6‐Trinitrophenol and Nitrofurantoin

AbstractA novel 3D MOF [Cd2(IPA)2L0.5(CH3OH)] (CUST‐535) (H2IPA=isophthalic acid; L=9,10‐bis(N‐benzimidazolyl)‐anthracene) with rectangular 2D layer has been rationally synthesized under solvothermal conditions using ligand L with fluorescence properties. CUST‐535 displays a fascinating 6‐connected 3D network based on the point symbol {36 ⋅ 418}. The excellent structural stability of CUST‐535 was also verified by PXRD and TGA. Remarkably, thanks to the presence of the anthracene‐based chromophore, CUST‐535 exhibits strong blue light emission and shows sensitive and rapid fluorescence “turn‐off” detecting of trace amounts of 2,4,6‐trinitrophenol (TNP) and nitrofurantoin (NFT) in DMF. The limit of detection (LOD) for TNP and NFT are 0.374 μM and 0.675 μM, respectively. In the end, the mechanisms of fluorescence quenching have also been systematically studied through theoretical calculations and experiments.

Two Cu(II) coordination polymers based on isomeric N-heterocyclic multicarboxylate ligands: Construction and magnetic properties

Two novel Cu(II) coordination polymers, namely, [Cu2(HL1)2]n·2nCH3CN·nH2O (1), [Cu(HL2)(H2O)]n(2), were solvothermally synthesized by isomeric N-heterocyclic multicarboxylate ligands (H3L1= 5-(3,4-dicarboxylphenoxy)nicotic acid, H3L2 = 5-(2,3-dicarboxylphenoxy)nicotic acid). Complex 1 possess the [Cu2(COO)4] SBUs and displays a 2D kgd topological network with the point symbol of (43)2(46·66·83). Complex 2 shows a three-dimensional supramolecular structure with a single-node SP 2-periodic net (6,3)Id topology with a topological symbol of (42·64). Meanwhile, magnetic studies show that complex 2 exhibits antiferromagnetic behavior.

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).

Syntheses, structures, and properties of three new complexes (Co(II), Cd(II), Zn(II)) assembled with 3-(2,4-di-carboxyphenoxy)phthalic acid

Three new complexes with three-periodic (3D) structure were synthesized by hydrothermal method with 3-(2,4-di-carboxyphenoxy)phthalic acid (H4L) as main ligand, 1,4-bis((1H-imidazol-1-yl)methyl)benzene (bix) and 1,4-di(pyridin-4-yl)benzene (4,4′-bipb) as co-ligands: [Co2(L)(bix)(H2O)]n (1), { [Cd2(L)(bix)0.5(H2O)2]H2O}n (2), [Zn2(L)(4,4′-bipb)]n (3). Complex 1 shows a 4,6-coordinated 3D new topology with a point symbol of {43.63}{43.69.83}, 2 displays a 3,8-coordinated 3D 3,8T12 topology with a point symbol of {43}2{46.614.88}, and 3 exhibits a 4,4,6-coordinated 3D new topology with a point symbol of {32.42.52}2{34.42.619.72.8}{34.44.54.62.8}. Moreover, the intermolecular interaction and surface electron distribution of 1-3 were analyzed by Hirshfeld surface analysis; The luminescent properties of 2 and 3 have been explored and compared with that of the ligand. Magnetic properties analyses of 1 were performed.

Two multifunctional luminescent cobalt metal-organic frameworks for selectively and sensitively sensing of Cu2+, MnO4- and picric acid in water

Developing novel metal-organic frameworks (MOFs) and exploring their luminescent applications gains continuous concern. Herein, based on tetraphenylpyrazine fluorophore, two cobalt metal-organic frameworks (MOFs), denoted as {Co(HCOO)(Tipp)·H2O}n(1) and {Co(Tipp)0.5A}n(2) (Tipp ​= ​2, 3, 5, 6-tetrakis[4-[(1H-imidazole-1-yl)-methyl]phenyl]pyrazine, H2A ​= ​4, 4'-oxybisbenzoic acid), have been prepared under hydrothermal condition. Structural analysis indicates that 1 has a (4, 6)-connected 3D seh network with the point symbol of {3∙42∙52∙6}{32∙42∙52∙64∙74∙8}. 2 shows a (2, 4)-connected 2D framework with a new Schläfli symbol of {42∙82∙102}{42∙83∙10}2{4}2. Significantly, 1 and 2 can be employed as multifunctional sensors for selective and sensitive detection of Cu2+, MnO4- and picric acid in aqueous solution by fluorescence quenching. The limits of detection (LODs) for Cu2+, MnO4- and picric acid were down to 10-7 ​M and quenching constant (Ksv) values reach the level of 105 ​M-1. Moreover, the two sensors show good recyclability and can respond to analytes in a wide pH range.