Sorption Behavior and Magnetic Properties of A Heterometallic Organic Framework with Octahedral Cages and One‐Dimensional Channels

The Zn^II‐Co^II organic framework [Me₂NH₂][Zn₂Co(μ₃‐OH)(BTC)₂(H₂O)] · 2H₂O ( FJI‐6 ) (H₃BTC = 1, 3,5‐benzenetricarboxylic acid and DMA = N.N′‐dimethyl acetamide), was synthesized and structurally characterized. FJI‐6 shows a three‐dimensional heterometallic microporous framework with coexisting octahedral cages and one‐dimensional channels assembled by Zn₂Co(μ₃‐OH)(CO₂)₆ secondary building units. In addition, the sorption behavior and magnetic properties of FJI‐6 were investigated.     

Synthesis,Structure, and Characterization of a Microporous Metal‐Organic Framework with PtS Topology

The microporous metal‐organic framework Cd₂(ABTC)(H₂O)(DMA)₂ · H₂O · 3DMA ( 1 ) (H₄ABTC = 3, 3′,5, 5′‐azobenzenetetracarboxylic acid; DMA = N,N′‐dimethylacetamide) was prepared by solvothermal reaction and characterized. X‐ray structure analysis revealed that compound 1 is a three‐dimensional (3D) open framework with 2D channels. The topology is based on a PtS net, constructed of 4‐connected rectangular ABTC^4– units with 4‐connected tetrahedral dinuclear Cd₂(CO₂)₄(H₂O)(DMA)₂ secondary building units (SBUs). The solid‐state excitation‐emission spectra showed that the strongest emission peak is at 403 nm upon excitation at λ = 287 nm.     

Synthesis,Structure, Photoluminescence,and Theoretical ­Calculation of an rtl‐type Zinc(II) Compound with Linear Trinuclear [Zn3(COO)4(μ2‐H2O)2] Subunits

The zinc(II) coordination polymer [Zn₃(BPT)₂(μ₂‐H₂O)₂(H₂O)₂]_n · n(DMA) ( 1 ) (H₃BPT = biphenyl‐3,4′,5‐tricarboxylic acid, DMA = N,N′‐dimethylactamide) was obtained by the solvothermal reaction of H₃BPT with Zn(NO₃)₂ in DMA/H₂O mixed solvent. Single crystal X‐ray analysis reveals that compound 1 has a complicated 3D framework containing linear trinuclear [Zn₃(COO)₄(μ₂‐H₂O)₂] clusters as building subunits, which can be simplified into a (3,6)‐connected rtl topological network with the Schläfli symbol {4.6²}₂{4².6¹⁰.8³}. The calculated results of total and partial density of states (DOS) indicate that the luminescence of 1 mainly originates from intraligand charge transfer.     

Solvent‐Dependent Synthesis from Layer to Microporous Pillared‐Layer Framework for Selective Sorption of Gas Light Hydrocarbons

Three metal‐organic frameworks, [Zn₃(bdc)₃(DMA)₂] ( 1 ) (H₂bdc = terephthalic acid; DMA = N,N‐dimethylacetamide), [Zn₃(bdc)₃(DMA)(DMPU)] ( 2 ) (DMPU = 1,3‐dimethylpropyleneurea), and [Zn₃(bdc)₄(Hdma)₂] ( 3 ) [Hdma = protonated dimethylamine (Me₂NH₂)] were synthesized by using different solvents. The solvents determine the framework architectures range from layer to microporous pillared‐layer framework. The microporous framework has 8‐connected bcg topology and shows selective sorption ability for gas light hydrocarbons.     

Syntheses,Structures, Luminescence,and Gas Adsorption Properties of Two New Heterometallic Complexes Involving Alkaline Earth Metals (Ca,Ba)

Two new 3D heterometallic frameworks, [Me₂NH₂][CaCd₂(BTC)(HBTC)₂] · 4H₂O ( 1 ) and [Ba₁₁Co₂(BTC)₈(μ₃‐OH)₂(μ₂‐H₂O)₆(H₂O)₁₆] ( 2 ) (H₃BTC = 1,3,5‐benzenetricarboxylic acid, Me₂NH₂ = protonated dimethylamine), were synthesized using solvothermal and hydrothermal techniques, respectively. Complex 1 features a 3D microporous framework; it contains hourglass‐like trinuclear [CaCd₂(COO)₆] clusters that are bridged by –COO^– groups and form zigzag chains. These chains are further interlinked by the –COO^– groups of BTC^3– ligands into 2D layers with interesting flower‐like configuration, which, in turn, are connected by HBTC^2– ligands to afford the 3D structure. Me₂NH₂⁺ cations not only balance the negative charges of the host framework but also play template roles to fill in the channels, further consolidating the whole framework. The complicated 3D network of complex 2 is constructed by the interconnection of 2D layers, which, in turn, are made of the infinite inorganic chains based on hexanuclear [Ba₆] clusters, and these 1D chains are decorated by {CoO₆} octahedrons. Interestingly, the 2D layer can be viewed as a unique structure composed of two different kinds of heart‐shaped rings, which partially overlapped in apical positions to produce a ten‐membered ring window. Moreover, the luminescence properties of 1 – 2 and the gas adsorption property of 1 have also been studied.     

Detection and Quantifiable Evaluation of Copper(II) Ions through Luminescent Sensing between Two Homologous Metal‐organic Frameworks

Two luminescent metal‐organic frameworks (LMOFs), namely, [Cd₂(DDCPB) · (DMF)₂ · H₂O]_n (CHD‐ 1 ) and [Zn₂(DDCPB) · (DMA)₂]_n · n(DMA) (CHD‐ 2 ), were solvothermally constructed, which present structural diversity. Single crystal X‐ray diffraction analysis indicates that they consist of [Cd₂(μ2‐O)₂(κ‐O)₂] building units (for CHD‐ 1 ), [Zn₂(κ‐O)₆] building units (for CHD‐ 2 ), which are further linked by multicarboxylate H₄DDCPB to construct microporous frameworks. Remarkably, both CHD‐ 1 and 2 exhibit highly efficient luminescent sensing for environmentally relevant Cu²⁺ ions through luminescence quenching. Theoretical and experimental calculations indicate that the luminescent quenching can be attributes to the donor‐acceptor electron transfer between the MOFs and analytes. This work indicates that CHD‐ 1 and 2 could be taken as a potential candidate for developing multifunctional luminescence sensors.     

Untersuchung von Hydrolysereaktionen zum Aufbau von Eisen(III)‐Oxo‐Aggregaten

Investigation of the Hydrolytic Build‐up of Iron(III)‐Oxo‐Aggregates The synthesis and structures of five new iron/hpdta complexes [{Fe^III₄(μ‐O)(μ‐OH)(hpdta)₂(H₂O)₄}₂Fe^II(H₂O)₄]·21H₂O ( 2 ), (pipH₂)₂[Fe₂(hpdta)₂]·8H₂O ( 4 ), (NH₄)₄[Fe₆(μ‐O)(μ‐OH)₅(hpdta)₃]·20.5H₂O ( 5 ), (pipH₂)_1.5[Fe₄(μ‐O)(μ‐OH)₃(hpdta)₂]·6H₂O ( 7 ), [{Fe₆(μ₃‐O)₂(μ‐OH)₂(hpdta)₂(H₄hpdta)₂}₂]·py·50H₂O ( 9 ) are described and the formation of these is discussed in the context of other previously published hpdta‐complexes (H₅hpdta = 2‐Hydroxypropane‐1, 3‐diamine‐N, N, N′, N′‐tetraacetic acid). Terminal water ligands are important for the successive build‐up of higher nuclearity oxy/hydroxy bridged aggregates as well as for the activation of substrates such as DMA and CO₂. The formation of the compounds under hydrolytic conditions formally results from condensation reactions. The magnetic behaviour can be quantified analogously up to the hexanuclear aggregate 5 . The iron(III) atoms in 1 ‐ 7 are antiferromagnetically coupled giving rise to S = 0 spin ground states. In the dodecanuclear iron(III) aggregate 9 we observe the encapsulation of inorganic ionic fragments by dimeric{M₂hpdta}‐units as we recently reported for Al^III/hpdta‐system.     

Synthesis,structure and selective luminescence sensing for iron(III) ions of a three‐dimensional zinc(II) (4,6)‐connected coordination network

Coordination polymers constructed from conjugated organic ligands and metal ions with a d¹⁰ electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A Zn^II‐based coordination polymer, namely poly[aqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)(μ₂‐4,4′‐bipyridine)dizinc(II)], [Zn₂(C₁₆H₆O₈)(C₁₀H₈N₂)(H₂O)₂]_n or [Zn₂(m,m‐bpta)(4,4′‐bipy)(H₂O)₂]_n, was synthesized from a mixture of biphenyl‐3,3′,5,5′‐tetracarboxylic acid [H₄(m,m‐bpta)], 4,4′‐bipyridine (4,4′‐bipy) and Zn(NO₃)₂·6H₂O under solvothermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis, and features a μ₆‐coordination mode. The Zn^II ions adopt square‐pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn₂(COO)₂] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m‐bpta)^4? ligands to produce a two‐dimensional grid‐like layer that exhibits a stair‐like structure along the a axis. Adjacent layers are linked by 4,4′‐bipy ligands to form a three‐dimensional network with a {4⁴.6¹⁰.8}{4⁴.6²} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe³⁺ ions.     

Three new ZnII coordination polymers constructed from a semi‐rigid tricarboxylic acid: structural changes caused by flexibility and luminescence sensing for hexavalent chromate anions

Coordination polymers (CPs) with specific structures and functional luminescence have been widely designed as sensors for detecting small molecules and ions. In this study, with or without the help of an N‐donor auxiliary linker, three new Zn^II CPs, namely, three‐dimensional (3D) poly[[pentaaquabis[μ₃‐5‐(4‐carboxybenzyloxy)isophthalato]bis[μ₆‐5‐(4‐carboxylatobenzyloxy)isophthalato]di‐μ₃‐hydroxido‐hexazinc(II)] trihydrate], {[Zn₆(C₁₆H₁₀O₇)₂(C₁₆H₉O₇)₂(OH)₂(H₂O)₅]·3H₂O}_n or {[Zn₆(μ₃‐HL)₂(μ₆‐L)₂(μ₃‐OH)₂(H₂O)₅]·3H₂O}_n, ( I ), one‐dimensional (1D) catena‐poly[[[aqua(1,10‐phenanthroline)zinc(II)]‐μ₂‐5‐(4‐carboxybenzyloxy)isophthalato] dihydrate], {[Zn(C₁₆H₁₀O₇)(C₁₂H₈N₂)(H₂O)]·2H₂O}_n or {[Zn(μ₂‐HL)(phen)(H₂O)]·2H₂O}_n (phen is 1,10‐phenanthroline), ( II ), and 3D poly[diaquatetrakis(4,4′‐bipyridine)bis[μ₆‐5‐(4‐carboxylatobenzyloxy)isophthalato]di‐μ₃‐formato‐di‐μ₃‐hydroxido‐pentazinc(II)], [Zn₅(C₁₆H₉O₇)₂(HCOO)₂(OH)₂(C₁₀H₈N₂)₄(H₂O)₂]_n or [Zn₅(μ₄‐L)₂(bpy)₄(μ₂‐OH)₂(μ₃‐HCOO)₂(H₂O)₂]_n (bpy is 4,4′‐bipyridine), ( III ), have been constructed from the semi‐rigid tricarboxylic acid 5‐(4‐carboxybenzyloxy)isophthalic acid (H₃L) under hydrothermal conditions. CP ( I ) exhibits a twofold interpenetrated 3D+3D→3D skeleton with a 3 , 5 ‐conn topology constructed from triangular trinuclear [Zn₃(COO)₄(μ₃‐OH)] clusters, in which the H₃L ligand adopts three different coordination modes. CP ( II ) exhibits a 1D infinite chain and stacking that gives a 3D structure mediated by hydrogen bonds and weak interactions. CP ( III ) is an interesting 3D 3 , 4 , 8 ‐conn network including linear tetranuclear [Zn₄(μ₂‐OH)₂(HCOO)₂(COO)₂] clusters with a new {4·6²}₂{4·6⁴·8}{4⁶·6¹⁹·8³} topological symbol. The influences of the flexible –CH₂–O– linker of the H₃L ligand and subtle environmental factors, such as solvent, pH value and auxiliary ligands, on the formation of the final structures are also discussed. The solid‐state fluorescence spectra of CPs ( I )–( III ) were recorded at room temperature and all show better fluorescence performances than H₃L. In particular, ( II ) can act as a potential multifunctional fluorescent material for sensing hexavalent chromium ions in aqueous solution with high stability, selectivity and sensitivity. Under ultraviolet light of 365 nm from a UV lamp, a signal response of fluorescence from turning on to off can be observed with the naked eye. It was found that the detection for hexavalent chromium (i.e. Cr₂O₇^2?) by ( II ) has a high selectivity [K_SV = 1.61 × 10⁴M^?1 and limit of detection (LOD) = 0.434 µM] in aqueous solution. Quenching mechanisms were also studied in detail.     

X-ray diffraction study of Al-Si melts

New layered metal-organic coordination polymers [Zn₃(bpdc)₃(DMA)₂]·3DMA (1) (H₂bpdc = 4,4′-biphenyldicaboxylic acid, DMA = N,N′-dimethylacetamide) and [Zn₃(bdc)₃(im)₂]·1.5H₂O (2) (H₂bdc = terephtalic acid, im = imidazole) are synthesized and characterized by X-ray crystallography.     

Two non-interpenetrating 3D coordination networks with (3, 4)-connected topologies

Two new coordination polymers, namely [Zn₃(1,3,5-BTC)₂(L¹)₂(H₂O)₂] · 2H₂O (1) and [Cd₃(1,2,3-BTC)₂(L²)₃] · H₂O (2) (where L¹ = 1,2-bis(imidazol-1-ylmethyl)benzene, L² = 1,1′-(1,4-butanediyl)bis(imidazole), 1,3,5-H₃BTC = 1,3,5-benzenetricarboxylic acid and 1,2,3-H₃BTC = 1,2,3-benzenetricarboxylic acid), were synthesized in hydrothermal conditions. In 1, each 1,3,5-BTC anion coordinates to three Zn cations, and the framework of 1 can be simplified as (6 · 8 · 10)₂(6² · 8 · 10³)(8² · 10)(6² · 10) topology. In 2, 1,2,3-BTC anions coordinate to three cadmiums, and the whole structure displays a (6² · 8⁴)₂(6⁴ · 8 · 10)(6² · 8)₂ network containing three different types of nodes. The luminescent properties for 1 and 2 are discussed.     

A novel three‐dimensional tetranuclear CoII coordination polymer with water hexamers based on the V‐shaped tetracarboxylate ligand 4‐(2,4‐dicarboxylatophenoxy)phthalate

A new coordination polymer (CP), namely, poly[[diaquatris[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]bis[μ₆‐4‐(2,4‐dicarboxylatophenoxy)phthalato]tetracobalt(II)] hexahydrate], {[Co₄(C₁₆H₆O₉)₂(C₁₂H₁₀N₄)₃(H₂O)₂]·6H₂O}_n, has been synthesized by solvothermal reaction. The CP was fully characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single‐crystal X‐ray diffraction. It presents a three‐dimensional (3D) structure based on tetranuclear Co^II secondary building units (SBUs) with a tfz‐d net and point symbol (4³)₂(4⁶·6¹⁸·8⁴). The 4‐(2,4‐dicarboxyphenoxy)phthalic acid (H₄dcppa) ligands are completely deprotonated and link {Co₄(COO)₄}^4? SBUs into two‐dimensional (2D) layers. Furthermore, adjacent layers are connected by 1,4‐bis(1H‐imidazol‐1‐yl)benzene (bib) ligands, giving rise to a 3D supramolecular architecture. Interestingly, there are numerous elliptical cavities in the CP where isolated unique discrete hexameric water clusters have been observed. The results of thermogravimetric and magnetic analyses are described in detail.     

Synthesis and Characterization of New M‐Triazole Complexes (M = Co,Cu, Zn)

Three new complexes with the ligand 3,5‐diamino‐1,2,4‐triazole (Hdatrz), [Co₃(μ₂‐Hdatrz)₆(H₂O)₆]·(NO₃)₈·4H₂O ( 1 ), [Cu₃(μ₂‐Hdatrz)₄(μ₂‐Cl)₂(H₂O)₂Cl₂]·Cl₂·4H₂O·2C₂H₅OH ( 2 ) and {[Zn₂(μ₂‐SO₄) (μ₃‐datrz)₂]·2H₂O}_n ( 3 ) have been synthesized and structurally characterized. Complex 1 has a linear trinuclear mixed‐valence cobalt structure with six neutral triazole ligands in the N(1), N(2)‐bridging mode. The central cobalt atom, Co(1), is coordinated to six nitrogen atoms (octahedral) whereas the terminal cobalt atom, Co(2), is coordinated to an N₃O₃ moiety (octahedral). In complex 1 , the uudd cyclic water clusters, nitrate anions and the trimeric cations are linked to a supramolecular structure. Complex 2 features a linear trinuclear copper(II) core, with four N(1), N(2)‐bridging triazole ligands and two chlorido bridges. The central copper atom is coordinated to an N₄Cl₂ moiety (octahedral) whereas the terminal copper is coordinated to an N₂Cl₂O moiety (square‐pyramidal). In complex 2 , tetrahedral hydrogen bonding interactions play an important role to form a supramolecular network. Complex 3 exhibits a polymeric structure, with N(1), N(2), N(4)‐bridging triazolate ligands and sulfate bridges, in which zinc is coordinated to an N₃O moiety (tetrahedral). In complex 3 , water molecules and sulfate anions construct the sulfate‐water supramolecular chain with hydrogen bonding interactions. In addition, the complexes were investigated by elemental analyses, IR spectroscopic, and thermogravimetric measurements.     

ChemInform Abstract: Tetrakis(tetramethylammonium) Tricarbonatodioxidouranate Octahydrate.

Single crystals of (Me₄N)₄ [UO₂(CO₃)₃]·8H₂O are grown by slow evaporation (25 °C, 6 weeks) of an aqueous solution of uranyl 1‐hydroxyethane‐1,1‐diphosphonate and Me₄NOH.     

Synthesis,crystal structure and photoluminescence of a three‐dimensional zinc coordination compound with NBO‐type topology

The assembly of metal–organic frameworks (MOFs) with metal ions and organic ligands is currently attracting considerable attention in crystal engineering and materials science due to their intriguing architectures and potential applications. A new three‐dimensional MOF, namely poly[[diaqua(μ₈‐para‐terphenyl‐3,3′,5,5′‐tetracarboxylato)dizinc(II)] dimethylformamide disolvate monohydrate], {[Zn₂(C₂₂H₁₀O₈)(H₂O)₂]·2C₃H₇NO·H₂O}_n, was synthesized by the self‐assembly of Zn(NO₃)₂·6H₂O and para‐terphenyl‐3,3′,5,5′‐tetracarboxylic acid (H₄TPTC) under solvothermal conditions. The compound was structurally characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction analysis. Each Zn^II ion is located in a square‐pyramidal geometry and is coordinated by four carboxylate O atoms from four different TPTC^4? ligands. Pairs of adjacent equivalent Zn^II ions are bridged by four carboxylate groups, forming [Zn₂(O₂CR)₄] (R = terphenyl) paddle‐wheel units. One aqua ligand binds to each Zn^II centre along the paddle‐wheel axis. Each [Zn₂(O₂CR)₄] paddle wheel is further linked to four terphenyl connectors to give a three‐dimensional framework with NBO‐type topology. The thermal stability and solid‐state photoluminescence properties of the title compound have also been investigated.     

Multidimensional Snowflake‐shaped (3, 9)‐connected Metal‐Organic Frameworks Composed of Ni3(μ3‐O) Building Blocks and Symmetry Ligand Pyridine‐3,5‐dicarboxylic Acid

A metal‐organic polymer [Ni₃(μ₃‐O)(PDB)₃]·H₂O ( 1 ) (PDB = pyridine‐3,5‐dicarboxylate), with antiferromagnetic interactions between the adjacent Ni atoms, containing trinuclear μ₃‐oxo‐bridged metal units Ni₃(μ₃‐O) have been synthesized by hydrothermal reaction of the achiral building blocks pyridine‐3,5‐dicarboxylate (3,5‐PDB) and Ni(NO₃)₂·4H₂O. Compound 1 shows a high symmetry three‐dimensional snowflake‐shaped (3, 9)‐connected topology structures in which μ₃‐oxo mixed‐valence Ni₃O(CO₂)₆ clusters act as nine‐connected nodes and PDB ligands act as three‐connected nodes.     

Chemical Fixation of CO2 and Other Heterogeneous Catalytic Studies by Employing a Layered Cu‐Porphyrin Prepared Through Single‐Crystal to Single‐Crystal Exchange of a Zn Analogue

A solvothermal reaction of Zn(NO₃)₂ ? 6 H₂O, tetra‐(4‐pyridyl)porphyrin (H₂TPyP), and 4,4′‐oxybis(benzoic acid) (H₂OBA) resulted in a new two‐dimensional Zn‐ porphyrin metal–organic framework compound, [Zn₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₆ ( 1 ; DMA=N,N‐dimethylacetamide). The Zn^II ions present in 1 could be exchanged by using a solution of Cu(NO₃)₂ ? 3 H₂O in DMA at room temperature to give [Cu₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₃ ( Cu∈1 ). The extra‐framework solvent molecules have been shown to be reversibly removed or exchanged without collapse of the framework. Solvent‐free Cu∈1 was explored as an active heterogeneous catalyst towards three different organic reactions: 1) the chemical fixation of CO₂ into cyclic carbonate at room temperature and 1 atm; 2) the nitroaldol reaction under solvent‐free conditions, and 3) the three‐component coupling of aminopyridine, benzaldehyde, and aryl alkynes followed by 5‐exo‐dig cyclization to produce the important pharmacophore imidazopyridine.     

Metal-ion-dependent,Solvent-mediated Structural Transformation and Simultaneous Partial Transmetalation of an srs Framework into Desulfurization-efficient Co-Cu-HKUST-1

[Co₂(BTC)(Cl)(DMA)₃] ( 1 ) (BTC^3– = benzene-1,3,5-tricarboxylate, DMA = N,N-dimethylacetamide) obtained from the reaction between Co²⁺ and H₃BTC in DMA features a three-dimensional srs framework built of 3-connected {Co₂(COO)₃} as secondary building units and BTC^3– as spacers. When exposed to DMA solution of Cu(NO₃)₂, 1 was progressively transformed into the first heterometallic Co-Cu-HKUST-1 ([Co_0.14Cu_2.86(BTC)₂]) ( 2 ) of such kind via unusually solvent-mediated structural transformation and simultaneous partial transmetalation. While the mechanism for such conversion is proposed based on systematic studies, 2 was revealed to be an equally efficient desulfurization adsorbent as the homometallic Cu-HKUST-1 in removing thiophene (0.142 mmol S per gram of adsorbent). However, when exposed to Zn(NO₃)₂ solution in DMA for longer time, 1 retained its framework with limited metal-ion exchange, resulting in the formation of [Co_1.93Zn_0.07(BTC)(Cl)(DMA)₃] ( 3 ). Possible reasons responsible for the formation of 2 and 3 through different routes could be due to the less solubility and more thermodynamic stability of 2 in comparison with those of 1 , and the different coordination geometries which Co²⁺, Zn²⁺ and Cu²⁺ prefer.     

Two ZnII‐based MOFs constructed with biphenyl‐2,2′,5,5′‐tetracarboxylic acid and flexible N‐donor ligands: syntheses,structures and properties

Two new Zn²⁺‐based metal–organic frameworks (MOFs) based on biphenyl‐2,2′,5,5′‐tetracarboxylic acid, i.e. H₄(o,m‐bpta), and N‐donor ligands, namely, poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·C₃H₇NO·2H₂O}_n or {[Zn₂(o,m‐bpta)(1,3‐bimb)₂]·C₃H₇NO·2H₂O}_n ( 1 ) {1,3‐bimb = [1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}, and poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] monohydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·H₂O}_n or {[Zn₂(o,m‐bpta)(1,4‐bimb)₂]·H₂O}_n ( 2 ) {1,4‐bimb = [1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis. Structurally, the (o,m‐bpta)^4? ligands are fully deprotonated and combine with Zn²⁺ ions in μ₄‐coordination modes. Complex 1 is a (3,4)‐connected porous network with honeycomb‐like [Zn₂(o,m‐bpta)]_n sheets formed by 4‐connected (o,m‐bpta)^4? ligands. Complex 2 exhibits a (2,4)‐connected network formed by 4‐connected (o,m‐bpta)^4? ligands linking Zn²⁺ ions in left‐handed helical chains. The cis‐configured 1,3‐bimb and 1,4‐bimb ligands bridge Zn²⁺ ions to form multi‐membered [Zn₂(bimb)₂] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H₄(o,m‐bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C_2v polar point group.     

New Series of Porous Ionic Crystals Constructed from Various Polyoxometalate Anions and Macrocations: Syntheses,Crystal Structures,and Comparison with Diverse Spatial Arrangement

A new series of ionic crystals, KH₂[Cr₃O(OOCCH₃)₆(H₂O)₃][α‐SiMo₁₂O₄₀] · 11 H₂O ( 1 ), KH₂[Cr₃O(OOCCH₃)₆(H₂O)₃][α‐SiW₁₂O₄₀]μ·μ11H₂O ( 2 ), K₂[Cr₃O(OOCCH₃)₆ (H₂O)₃][α‐PW₁₂O₄₀]μ· 17H₂O ( 3 ), Na[Cr₃O(OOCCH₃)₆(H₂O)₃]₂[α‐PMo₁₂O₄₀] · 11H₂O ( 4 ), H₅[Cr₃O(OOCCH₃)₆(H₂O)₃] [α‐P₂Mo₁₈O₆₂] · 10H₂O ( 5 ) based on a polyoxometalate building block with a macrocation, have been synthesized in aqueous solution and structurally characterized by single‐crystal X‐ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The polyanions and macrocations stacked alternately through hydrogen bonds as well as electrostatic interactions to constitute a novel porous microstructure. In the crystal structures of 1 , 2 , and 3 , oppositely charged cluster ions stacked alternately to form one‐dimensional channels. Compound 4 exhibits an unique structure that six macrocation pillars packed along the a‐axis to form a straight 1D channel, in which accommodates a polyoxometalate pillar. In compound 5 , six α‐Dawson‐type polyoxometalate pillars stacked on top of each other along the a‐axis to form a straight 1D channel, which houses a macrocation pillar. The magnetic investigation on compounds 1 and 5 shows a typical antiferromagnetic interaction of the macrocation [Cr₃O(OOCCH₃)₆(H₂O)₃]⁺, almost independent from the presence of polyoxometalate anions.