Aromatic Polycarboxylate Research Articles

A Novel Coordination Polymer Based on 4,4'-(Hexauoroisopropylidene)diphthalic Acid: Synthesis, Structure and Physical Properties

The design and synthesis of coordination polymers is an attractive area of research, not only owing to their diverse topology and intriguing structures but also due to their potential applications in many fields, such as ion-exchange, catalysis, luminescence, magnets, and gas storage. The mainstream method of constructing such coordination polymers is to utilize organic ligands with aromatic polycarboxylate groups, because of their excellent coordination capability and flexible coordination patterns. Among them, aromatic polycarboxylic derivatives, such as 1,2,4,5-benzenetetracarboxylic acid, 4,4'-oxydiphthalic acid, 4,4'-(hexauoroisopropylidene)diphthalic acid (H4FA), and so on, have been extensively used to prepare coordination polymers. Meanwhile, the flexible 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene (BTX) as an excellent derivative of triazole not only possesses the merits of triazole, but also can adopt different conformations compared with the corresponding 1,2,4-triazole ligand on the basis of the relative orientations of its CH2 groups. Taking these into consideration, we explored the self-assembly of Cd(II) ion, H4FA, and BTX under hydrothermal conditions, and obtained a novel 3D coordination polymer: [Cd3(BTX)2(HFA)2·2H2O]n. Herein, we report the synthesis, crystal structure, and physical properties.

A series of 2D metal–quinolone complexes: Syntheses, structures, and physical properties

Six novel 2D metal–quinolone complexes, namely [Cd(cfH)(bpdc)]H2O (1), [M(norfH)(bpdc)]H2O (M=Cd (2) and Mn (3)), [Mn2(cfH)(odpa)(H2O)3]0.5H2O (4), [Co2(norfH)(bpta)(μ2-H2O)(H2O)2]H2O (5) and [Co3(saraH)2(Hbpta)2(H2O)4]9H2O (6) (cfH=ciprofloxacin, norfH=norfloxacin, saraH=sarafloxacin, bpdc=4,4′-biphenyldicarboxylate, odpa=4,4′-oxydiphthalate, bpta=3,3′,4,4′-biphenyltetracarboxylate) have been synthesized and characterized. Compounds 1–3 consist of 2D arm-shaped layers based on the 1D {M(COO)}nn+ chains. Compounds 4 and 5 display 2D structures based on tetranuclear manganese or cobalt clusters with (3,6)-connected kgd topology. Compound 6 exhibits a 2D bilayer structure, which represents the first example of metal–quinolone complexes with 2D bilayer structure. By inspection of the structures of 1–6, it is believed that the long aromatic polycarboxylate ligands are important for the formation of 2D metal–quinolone complexes. The magnetic properties of compounds 3–6 was studied, indicating the existence of antiferromagnetic interactions. Furthermore, the luminescent properties of compounds 1–2 are discussed.

Aromatic Polycarboxylate-Tuned Assembly of Three New 2D Copper(II) Complexes Derived from a Flexible Bis(pyridylamide) Ligand

Three new 2D copper(ii) complexes [Cu(NIPH)(L)] (1), [Cu(BDC)(L)(H2O)] (2), and [Cu(HBTC)(L)]·2H2O (3) were hydrothermally synthesized by self-assembly of aromatic polycarboxylates (H2NIPH = 5-nitroisophthalic acid, H2BDC = 1,3-benzenedicarboxylic acid, H3BTC = 1,3,5-benzenetricarboxylic acid) and the flexible bis(pyridylamide) ligand L (L = N,N′-di(3-pyridyl)succinamide), and structurally characterized by single crystal X-ray diffraction, and elemental, IR, and thermogravimetric analyses. Compound 1 is a 2D coordination polymer based on tri-flexural helix chains (left-, right-handed [Cu-L]n helix chains, and left-handed Cu-NIPH helix chain). Compound 2 exhibits a 2D wavelike polymeric layer structure constructed from a 1D [Cu-L]n sinusoidal chain and a 1D [Cu-BDC]n V-like chain. Compound 3 possesses a 2D double-layer network formed from 1D [Cu-L]n zigzag chains and 1D [Cu-HBTC]2n double chains. The fluorescent properties of the three compounds and the electrochemical behaviour of compound 2-bulk-modified carbon paste electrode were also studied.

The Role of the Coordination Modes of a Flexible Bis(pyridylamide) Ligand in the Topology of 2D Copper(II) Complexes

Two new two-dimensional copper(II) coordination polymers, [Cu(L)(BDC)]_H2O (1) and [Cu2(L)0:5(SIP)(OH)(H2O)] 2H2O (2) [L=N;N0-bis(3-pyridylamide)-1,6-hexane, H2BDC=1,3- benzenedicarboxylic acid, H3SIP=5-sulfoisophthalic acid (3,5-dicarboxybenzenesulfonic acid)], have been synthesized hydrothermally by self-assembly of the flexible bis-pyridyl-bis-amide ligand L and the aromatic polycarboxylate ligands H2BDC or H3SIP. X-Ray diffraction analysis reveals that complex 1 displays a metal-organic coordination layer with a binodal (3,5)-connected {42.67.8}{42.6} topology, in which the L ligands adopt a m2-bridging mode (via ligation of the pyridyl nitrogen atoms). Complex 2 also exhibits a layered network based on tetranuclear copper clusters [Cu4(μ3-OH)2(H2O)2(O2C-)4], L ligands and SIP anions, showing a binodal (4,8)-connected network with {414.610.84}{44.62} topology, in which the L ligands adopt a μ6-bridging coordination mode (via ligation of the pyridyl nitrogen and carbonyl oxygen atoms). Adjacent layers in 1 and 2 are further linked by hydrogen bonding interactions to form three-dimensional supramolecular frameworks. The electrochemical behavior of the two complexes in bulk-modified carbon paste electrodes has been investigated

Series of Mixed Uranyl–Lanthanide (Ce, Nd) Organic Coordination Polymers with Aromatic Polycarboxylates Linkers

Three series of mixed uranyl-lanthanide (Ce or Nd) carboxylate coordination polymers have been successfully synthesized by means of a hydrothermal route using either conventional or microwave heating methods. These compounds have been prepared from mixtures of uranyl nitrate, lanthanide nitrate together with phthalic acid (1,2), pyromellitic acid (3,4), or mellitic acid (5,6) in aqueous solution. The X-ray diffraction (XRD) single-crystal revealed that the phthalate complex (UO(2))(4)O(2)Ln(H(2)O)(7)(1,2-bdc)(4)·NH(4)·xH(2)O (Ln = Ce(1), Nd(2); x = 1 for 1, x = 0 for 2), is based on the connection of tetranuclear uranyl-centered building blocks linked to discrete monomeric units LnO(2)(H(2)O)(7) via the organic species to generate infinite chains, intercalated by free ammonium cations. The pyromellitate phase (UO(2))(3)Ln(2)(H(2)O)(12)(btec)(3)·5H(2)O (Ce(3), Nd(4)) contains layers of monomeric uranyl-centered hexagonal and pentagonal bipyramids linked via the carboxylate arms of the organic molecules. The three-dimensionality of the structure is ensured by the connection of remaining free carboxylate groups with isolated monomeric units LnO(2)(H(2)O)(7). The network of the third series (UO(2))(2)(OH)Ln(H(2)O)(7)(mel)·5H(2)O (Ce(5), Nd(6)) is built up from dinuclear uranyl units forming layers through connection with the mellitate ligands, which are further linked to each other through discrete monomers LnO(3)(H(2)O)(6). The thermal decomposition of the various coordination complexes led to the formation of mixed uranium-lanthanide oxide, with the fluorite-type structure at 1500 °C (for 1, 2) or 1400 °C for 3-6. Expected U/Ln ratio from the crystal structures were observed for compounds 1-6.

Three new metal–organic complexes derived from N,N′-bis(3-pyridinecarboxamide)-1,2-ethane and polycarboxylate ligands: Synthesis, fluorescent and electrochemical properties

Three new metal–organic coordination polymers, [Cu2(3-dpye)(2,6-PDA)2(H2O)2] (1), [Cu2(3-dpye)(1,3,5-HBTC)2(H2O)3]·3H2O (2), [Cu(3-dpye)(1,3-BDC)(H2O)]·H2O (3), have been hydrothermally synthesized by using the flexible N,N′-bis(3-pyridinecarboxamide)-1,2-ethane (3-dpye) and different polycarboxylates [2,6-H2PDA = pyridine-2,6-dicarboxylic acid, 1,3,5-H3BTC = benzene-1,3,5-tricarboxylic acid, 1,3-H2BDC = benzene-1,3-dicarboxylic acid] as mixed ligands, and characterized by elemental analyses, IR, TG and single crystal X-ray diffraction. In complex 1, Cu(II) ions are bridged by 3-dpye to form dinuclear units, which are linked by hydrogen bonding interactions to construct a two-dimensional (2D) supramolecular layer. Complex 2 is a 2D coordination network with a new (3·72)2(3·73·82) topology based on two kinds of 1D polymeric chains: Cu-3-dpye chain and Cu-1,3,5-HBTC chain, and the adjacent 2D layers are packed into a 3D supramolecular structure through hydrogen bonding interactions. Complex 3 exhibits a 3D polymeric framework with threefold interpenetrating 4-connected (65·8) CdSO4-like topology, which represents the first example of 3D coordination polymers constructed from 3-dpye and aromatic polycarboxylate ligands. 3-dpye ligands adopt a μ2-bridging mode in 1 and 3 (via ligation of two pyridyl nitrogen atoms) and a μ3-bridging coordination mode in 2 (via ligation of two pyridyl nitrogen atoms and a carbonyl oxygen atom), which play an important role in the construction of final polymeric structures. The polycarboxylates with different coordination atoms also show obvious effect on structures of the title complexes. In addition, the electrochemical behaviors and the fluorescence properties of complexes 1–3 have been reported.

Syntheses, Structures, and Characteristics of Four New Metal–Organic Frameworks Based on Flexible Tetrapyridines and Aromatic Polycarboxylate Acids

Solvothermal reactions of tetrakis(4-pyridyloxymethylene)methane (TPOM) with deprotonated isophthalic acid (1,3-H2bdc), 5-hydroxyisophthalic acid (5-OH-H2bdc), benzene-1,3,5-tricarboxylic acid (H3btc), and benzene-1,2,4,5-tetracarboxylic acid (H4btc) in the presence of zinc and cobalt salts produce four new complexes, namely, {[Co2(TPOM)(bdc)2(H2O)2]·(H2O)3}n (1), {[Zn2(TPOM)(5-OH-bdc)2]·(DMF)(H2O)2}n (2), {[Co3(TPOM)(btc)2(H2O)]·(H2O)4}n (3), and {[Zn2(TPOM)(btc)2]n (4). Complexes 1 and 2 possess similar 2-fold interpenetrating three-dimensional (3D) framework with bbf topology, but 1 crystallizes in an achiral space group, and 2 crystallizes in chiral space group and displays ferroelectric behavior. Complex 3 reveals a 3D framework with biunclear Co clusters, which displays weak antiferromagnetic character. In complex 4, only H4btc links Zn(II) to generate a 3D porous framework, with TPOM occupying the void space as countercation and template. In addition, photochemical and ferroelectric properties of t...

Syntheses and structures of five 1D coordination polymers based on quinolone antibacterial agents and aromatic polycarboxylate ligands

A series of one-dimensional (1D) metal–quinolone coordination polymers, namely [Zn(levofH)(sdba)]·H2O (1), [M(cfH)(oba)(H2O)2] (M=Co (2) and Ni (3)), [Cu4(ppaH)2(btec)2(H2O)4]·3H2O (4) and [Cu4(norfH)2(btec)2(H2O)4]·3H2O (5) (levofH=levofloxacin, cfH=ciprofloxacin, ppaH=pipemidic acid, norfH=norfloxacin, sdba=4,4′-sulfonyldibenzoate, oba=4,4′-oxybis(benzoate), btec=1,2,4,5-benzenetetracarboxylate) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra and TG analyses. Compound 1 is a unique 1D chiral metal–levofH complex. Compounds 2 and 3 are isostructural and contain similar chains constructed from [M(cfH)2(H2O)2] fragments linked by oba ligands. The structures of compounds 4 and 5 are analogous and both feature ladders constructed from CuII ions linked by btec ligands. In addition, the magnetic property of compound 4 has been studied, which exhibits an antiferromagnetic interaction.

A Series of Ca(II) or Ba(II) Inorganic–Organic Hybrid Frameworks Based on Aromatic Polycarboxylate Ligands with the Inorganic M–O–M (M = Ca, Ba) Connectivity from 1D to 3D

Solvothermal reactions of Ca(NO3)2 or Ba(NO3)2 with aromatic carboxylate ligands afforded four new inorganic–organic hybrid frameworks, [Ca(PBDC)(H2O)3]n (1), [Ca(OBDC)(H2O)]n (2), [Ba5(OBDC)4(H2O)2(NO3)2]n (3), and [Ba3(BTC)2(H2O)4]n (4) (H2PBDC = terephthalic acid, H2OBDC = phthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid). These compounds have been fully characterized by single crystal X-ray diffraction, powder X-ray diffraction, satisfactory elemental analysis, IR spectra, and TG analysis. X-ray analysis shows that compound 1 features a one-dimensional chain (1D) structure with the I1O0 connectivity, both compound 2 and compound 3 feature a two-dimensional (2D) layer structure with the I1O1 connectivity, I2O0 connectivity, respectively, compound 4 features a three-dimensional (3D) framework with a rare I3O0 connectivity. Thermal stabilities and luminescent properties of compounds 1–4 and NLO property of compound 4 have also been investigated.

Two novel entangled metal–quinolone complexes with self-threading and polythreaded characters

Reactions of quinolones with metal salts in the presence of aromatic polycarboxylate ligands under hydrothermal conditions yield two novel entangled metal–quinolone complexes, namely [Cd2(saraH)2(bpdc)2]·4.5H2O (1) and [Mn(sara)2]·2.5H2O (2), (saraH=sarafloxacin, bpdc=4,4′-biphenyldicarboxylate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, X-ray powder diffraction, and TG analyses. Compound 1 is an uncommon 2D self-threading network, which represents the first entangled network constructed from mixed sarafloxacin and dicarboxylate ligands. Compound 2 exhibits a novel (2D→3D) polythreaded architecture that is constructed from 2D 44-sql nets with side arms, which represents the first example of polythreaded metal–sarafloxacin complex. A comparison of the structures of 1 and 2 shows that the pH plays a crucial role in tuning the structures of the metal–quinolone complexes. Furthermore, the luminescent properties of compound 1 are discussed.

A series of coordination polymers constructed from in situ amidation ligands: syntheses, structures and luminescent properties

From the hydrothermal in situ amidation reactions of aromatic polycarboxylates and hydrazine hydrate (N2H4·H2O), four complexes, dinuclear [Cu(μ2-H3bbch)(H2O)]2·2H2O (1), 3-D grid-like [Fe3(μ5-Hbbch)2(μ2-H2O)2(H2O)2]·2H2O (2), 2-D layer [Zn(μ2-H2bbh)(μ2-N2H4)1/2(H2O)]·2H2O (3) and 3-D supramolecular structure [Cd(H2bch)2(2,2′-bpy)(H2O)2][Cd(μ2-H2bch)(2,2′-bpy)(H2O)2](H2bch) (4) have been prepared. The two different in situ amidated ligands in 1, 2 and 3, benzene-4,5-bicarboxylate-1,2-hydrazide (H4bbch) and benzene-1,2,4,5-bihydrazide (H4bbh), were formed through adjusting the ratios of pyromellitic acid (PMA) and N2H4·H2O, of which H4bbch was generated through hydrothermal in situ amidation reactions for the first time. Benzene-4-carboxylate-1,2-hydrazide (H3bch), displaying three new coordination modes in 4, was also an in situ amidation product of benzene-1,2,4-tricarboxylic acid (H3btca) and N2H4·H2O. 1–4 were characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. Their structures were determined by single-crystal X-ray diffraction. The fluorescence properties of compounds 1, 3 and 4 were also investigated.

Three-Dimensional Cd(II) Coordination Polymers Based on Semirigid Bis(Methylbenzimidazole) and Aromatic Polycarboxylates: Syntheses, Topological Structures and Photoluminescent Properties

To systematically explore the influence of aromatic polycarboxylate coligands on building high-dimensional Cd(II)-bmb (1,4-bis(2-methylbenzimidazol-1-ylmethyl) benzene) coordination polymers, we synthesized six coordination polymers, namely {[Cd(bmb)(o-phda)]·H2O}n (1), [Cd(bmb)0.5(m-phda)]n (2), [Cd(bmb)(p-phda)]n (3), [Cd(bmb)0.5(oba)]n (4), [Cd(bmb)(bpdc)]n (5), [Cd2(bmb)(bta)(mta)0.5]n (6), (H2phda = phenylenediacetic acid, H2oba =4,4′-oxybis(benzoic acid), H2bpdc = biphenyl-4,4′-dicarboxylic acid, H3bta =1,2,4-benzenetricarboxylic acid, and H2mta = 2-(methoxycabonyl)terephthalic acid) by varying aromatic polycarboxylate coligands. Structural analyses reveal that polymers 1–6 display diverse 3D frameworks and topologies, in which all of the N-donor ligands bmb exhibit trans-conformation but with different Ndonor···N–Csp3···Csp3 torsion angles. Polymer 1 shows a 3-fold interpenetrating dia array with a 4-connected 66 topology. Polymer 2 features a (3,4)-connected pillar-layered structure with (63)(65·8)-ins topology. Polymer 3 is a 4-connected framework with 66-dia topology and two types of meso-helical chains. Polymer 4 possesses a 2-fold interpenetrating 6-connected framework with (412·63)-pcu topology. The structure of polymer 5 is a 4-connected 5-fold interpenetrating architecture with 66-dia topology. Interestingly, in 6, part of bta3- anions are converted into a new ligand mta2- via in situ esterification reaction under solvothermal conditions. As a result, polymer 6 exhibits a scarce mixed-ligands framework with two O-donor and one N-donor ligands based on tetranuclear Cd(II) clusters. It is an 8-connected (36·418·53·6)-hex topology. A systematically structural comparison of these polymers indicates that the coordination modes of aromatic polycarboxylates along with the structural characteristics of the semirigid N-donor ligand bmb simultaneously play an important role in constructing the high-dimensional frameworks. Moreover, polymers 1–6 indicate high thermal stabilities and different photoluminescence behaviors in the solid state.

Crystal structures and luminescence of two cadmium(II) polymers constructed from aromatic polycarboxylate and bis(1,2,4-triazol-1-yl)methane ligands

Two new coordination compounds, {[Cd2(btrm)(ip)2(H2O)2] · 2H2O} n (1) and {[Cd2(btrm)(hip)2(H2O)4] · 3H2O} n (2) (btrm = bis(1,2,4-triazol-1-yl)methane, H2ip = isophthalic acid, H2hip = 5-hydroxy isophthalic acid), have been synthesized and structurally characterized. Compound 1 is a 3-D network with CdSO4 topology. Compound 2 contains 1-D ladder structures, which are interconnected by classical hydrogen-bonding interactions (O–H ··· O) to lead to 3-D supramolecular architectures. Luminescence was performed on 1 and 2, both of which showed strong fluorescent emissions in the solid state at room temperature.

Syntheses, structures, and properties of three cadmium(II) complexes constructed from aromatic polycarboxylate and flexible triazole synthons

Three new coordination compounds {[Cd(btrp)(ip)(H 2O)]·2.5H 2O} n ( 1) {[Cd(btrp)(hip)(H 2O)]·3H 2O} n ( 2) and {[Cd(btrp) 2(H 2O) 2]·H 2O·2H 2btc} n ( 3) (btrp = 1,3-bis(1,2,4-triazol-1-yl)propane, H 2ip = isophthalic acid, H 2hip = 5-hydroxy isophthalic acid, H 3btc = benzene-1,3,5-tricarboxylic acid) have been synthesized and structurally characterized. Both 1 and 2 feature two similar 2D layer structures, and the resulting 2D structures are interconnected by hydrogen-bond and π⋯π interactions to lead to 3D supramolecular architectures. 3 possesses 1D positive double-stranded chains. In the framework of 3, the free H 2btc ligands also constitute into supremolecular 1D negative chains through classical hydrogen-bonding interactions (O H⋯O). The two kinds of 1D chains constructs into 3D supramolecular architectures through hydrogen-bonding and electrostatic interactions. Luminescence analyses were performed on all the three compounds, 1 and 2 show strong fluorescent emissions in the solid state at room temperature.

Hydrothermal Syntheses of Metal–Organic Frameworks Constructed from Aromatic Polycarboxylate and 4,4′-Bis(1,2,4-triazol-1-ylmethyl)biphenyl

Six new metal–organic frameworks, namely, {[Co(btmb)(HBTC)]·2H2O}n (1), {[Co3(btmb)3(BTC)2(H2O)2]·6H2O}n (2), {[Co3(btmb)3(BTC)2(H2O)4]·2H2O}n (3), {[Ni3(btmb)3(BTC)2(H2O)4]·2H2O}n (4), [Cu(btmb)(HBTC)]n (5), and [Cu(btmb)(NDC)]n (6) (H3BTC = 1,3,5-benzenetricarboxylic acid, H2NDC = 1,2-benzenedicarboxylic acid, and btmb = 4,4′-bis(1,2,4-triazol-1-ylmethyl)biphenyl), have been synthesized under hydrothermal conditions. The structure of 1 is a 6-connected self-penetrating three-dimensional (3D) framework with 44·610·8 topology. Complex 2 exhibits a trinodal (3,4)-connected topology with a Schlafli symbol of (62·84)(64·82)(63). Both complexes 3 and 4 possess 3D pillar-layered structures with a Schlafli symbol of (62·8·103)(64·8·10)(6·102). Complex 5 is also a 3D polymer with a pillar-layered framework, which can be simplified as the (63)(69·8) topology. Complex 6 shows a 4-connected 3D framework with a Schlafli notation of (65·8)2. Furthermore, complexes 1–6 as heterogeneous catalysts were studied in the gr...

Copper(ii) metal–organic networks derived from bis(pyridylformyl)piperazineligands and aromatic polycarboxylates: 2D layered structures and a novel 3,5-connected binodal 3D topology

Three novel coordination polymers [Cu2(3-bpfp)(BDC)2(H2O)2]·4H2O (1), [Cu(3-bpfp)(HBTC)]·0.5H2O (2) and [Cu(4-bpfp)0.5(HBTC)(H2O)] (3) have been hydrothermally synthesized by self-assembly of aromatic polycarboxylate ligands H2BDC (H2BDC = 1,3-benzenedicarboxylate acid) or H3BTC (H3BTC = 1,3,5-benzenetricarboxylate acid), bridging ligands 3-bpfp/or 4-bpfp [3-bpfp = bis(3-pyridylformyl)piperazine, 4-bpfp = bis(4-pyridylformyl)piperazine], and copper chloride. X-Ray diffraction analysis reveals that each CuII ion is connected by BDC/or HBTC and 3-bpfp/or 4-bpfp ligands to form two dimensional (2D) layer structures in compounds 1 and 3. Ligands 3-bpfp and 4-bpfp both display μ4-bridging coordination mode in 1 and 3 (via ligation of pyridyl nitrogen and carbonyl oxygen atoms). In compound 2, each CuII ion is connected by HBTC to construct 2D polymeric layers, which are further linked into a novel 3,5-connected 3D coordination polymeric framework with (4·62)(4·66·83) topology by 3-bpfp ligand in μ2-bridging mode (via ligation of pyridyl nitrogen atoms). Compound 2 is the first 3D example of coordination polymer constructed from 3-bpfp and aromatic polycarboxylate ligands. Moreover, the electrochemical properties of the three copper compounds bulk modified carbon paste electrodes have been studied.

Coordination polymers based on a flexible bis(triazole) ligand and aromatic polycarboxylate anions: syntheses, topological structures and photoluminescent properties

Four new coordination polymers, namely, {[Cd(btmx)(BTEC)0.5(H2O)]·H2O}n (1), {[Cd(btmx)1.5(1,2,4-HBTC)]·(H2O)2}n (2), {[Co(btmx)(HBTC)]·2H2O}n (3) and [Co(btmx)(1,4-BDC)]n (4) (btmx = 1,4-bis(1,2,4-triazol-1-ylmethyl)-2,3,5,6-tetramethylbenzene, H4BTEC = 1,2,4,5-benzenetetracarboxylic acid, 1,2,4-H3BTC = 1,2,4-benzenetricarboxylic acid, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylic acid and 1,4-H2BDC = 1,4-benzenedicarboxylic acid) have been obtained under hydrothermal conditions and characterized structurally. Complex 1 is a 3D 3-fold interpenetrating (4,4)-connected net with (4·64·8)(42·62·82) topology. Complex 2 displays a 2D cabinet-like structure with infinite 1D double Cd–btmx chains. Complex 3 possesses a 3D 3-fold interpenetrating 4-connected framework with 66-dia topology. Complex 4 exhibits a (4,6)-connected 3D pillar-layered structure with point symbol of (44·62)(44·610·8). The structural differences of these complexes demonstrate that the flexible ligand btmx and aromatic polycarboxylate anions play critical roles in the formation of the resulting frameworks. Furthermore, the photoluminescent properties of 1 and 2 have been studied in the solid state at room temperature.

Surprising robustness of a unit cell: isomorphism in caesium 18-crown[6] complexes with aromatic polycarboxylate anions

Reaction in solution and in the solid state of 18-crown[6] with Cs2CO3 and 5-substituted isophthalic acids yields the new organic–inorganic complexes 18-crown[6]·Cs[OH-isoH] (2), 18-crown[6]·Cs[CH3-isoH] (3), 18-crown[6]·Cs[Br-isoH] (4), 18-crown[6]·Cs[OCH3-isoH] (5), 18-crown[6]·Cs[NO2-isoH] (6) and 18-crown[6]·Cs[tert-Butyl-isoH] (8), which have all been characterized by X-ray diffraction. All compounds except the latter are isomorphous, in spite of the size, shape and chemical nature of the substituent and its ability to form hydrogen bonds.

Syntheses, structures, photoluminescence and magnetic properties of four new metal–organic frameworks based on imidazoleligands and aromatic polycarboxylate acids

Four metal–organic coordination polymers, {[Cu2(4,4′-bibp)2(NO2)3)]·(NO2)(H2O)}n (1), [Cd(bdc)(4,4′-bibp)]n (2), {[Co2(bdc)2(4,4′-bibp)3(H2O)2]·(H2O)2}n (3), [Zn(Hbtc)(1,4-bix)]n (4) (4,4′-bibp = 4,4′-bis(1-imidazolyl)biphenyl; 1,4-bix = 1,4-bis((1H-imidazol-1-yl)methyl)benzene; H2bdc = 1,4-benzenedicarboxylate; H3btc = 1,3,5-benzenetricarboxylate) were obtained under hydrothermal conditions and characterized structurally. X-Ray diffraction analysis reveals that the four complexes exhibit new frameworks due to diverse coordination conformations. In copper compound 1, with mixed-valence copper(II)–copper(I), rigid linear 4,4′-bibp ligands connect two adjacent layers and the whole structure is a three-dimensional 6,6-connected network. In cadmium compound 2, 4,4′-bibp and bdc anions as bidentate ligands coordinate to cadmium cations to form a three-dimensional 4,4-connected network with a 3-fold interpenetrating framework. In cobalt compound 3, 4,4′-bibp and bdc anions also act as bidentate ligands, and coordinate to cobalt cations to form a three-dimensional 4,6-connected network. Zinc compound 4 shows that both the 1,4-bix ligand and btc anions act as bidentate bridging ligands, and connect the zinc cations to give a 2D polycatenated array structure. The magnetic properties for copper compound 1 and luminescent properties for cadmium compound 2 and zinc compound 4 are also discussed in detail.

Two unique antiferromagnetic 3D frameworks with unusual CuII4 cluster and alternate CuII4 + CuII1 structural motif tuned by aromatic polycarboxylate coligand

Two new 3-amino-1,2,4-triazole (amtrz)-based 3D MOFs, [Cu4(amtrz)2(μ3-OH)2(btc)2]n (1), and [Cu5(amtrz)2(H2O)2(μ3-OH)2(btec)2]n (2) (btc3− = 1,3,5-benzenetricarboxylate and btec4− = 1,2,4,5-benzenetetracarboxylate), were hydrothermally synthesized and structurally and magnetically characterized. Each cationic [Cu4(amtrz)2(μ3-OH)2]6+ cluster in 1 is periodically extended into an infinite 3,6-connected rtl-type topological network via six btc3− ligands. In contrast, analogous CuII4 clusters to 1 and square-planar CuII1 cores in 2 are alternately interlinked through btec4− linkers to generate a 3D (44·62)2(46·64)4(48·66·8)3 framework, which is a scarcely observed higher-dimensional coordination polymer with a CuII4 + CuII1 motif. More interestingly, both the coordination polymers display strong antiferromagnetic couplings up to −154.6 cm−1 due to the favorable multiple heterobridges in the analogous CuII4 component.