Two-fold Interpenetration Research Articles

Synthesis, crystal structures and properties of two coordination polymers constructed from M2+ (M2+=Zn2+, Ni2+) with methylenediisophthalic acid and 1,1′-(1,4-butanediyl)bis(imidazole)

Abstract Two coordination polymers [Zn2(H2L)2(bbi)(H2O)2·H2O]n 1 and [Ni4(L)2(bbi)2(H2O)4·H2O]n 2 {H4L = methylenediisophthalic acid, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)} have been prepared under hydrothermal conditions and structurally characterized by X-ray diffraction analyses. Mononuclear 1 is a 1D ladder chain and bbi adopts trans-configuration linking two metal centers. Plus the hydrogen binding interactions, it formed a 3D two-fold perpendicular interpenetrating (4, 5)-connected framework. Binuclear units of 2 are connected by L4− and cis-bbi to generate a 3D (4, 6)-connected framework, in which twisted bbi with binuclear units generate the rare triflexure helix. In solid state, complex 1 exhibits yellowgreen emissions at ambient temperature. Magnetic measurements show that there exist weak ferromagnetic interactions in 2.

Coordination polymers constructed from d10 ions, saturated or unsaturated aliphatic carboxylic acids, and bidentate nitrogen ligands: synthesis, characterization, and fluorescence

Five new coordination polymers synthesized from d10 metal ions, aliphatic carboxylic acids, and bidentate nitrogen ligands have been characterized with single crystallographic X-ray analysis, IR, and TG. Compound 1 has a twofold 3-D network. During the synthesis of 1, fumaric acid reacts with water giving malic acid, which coordinates Cd forming 2. If we use Zn instead of Cd, 1-D chain-like 3 is formed. With hydrogen bonds and π–π interactions, the 1-D covalent chains form a 3-D supramolecular network. The 3-D supramolecular networks connect together and form a twofold interpenetration structure. Compound 4 shows a 2-D layer structure. Compound 5 exhibits 1-D double-chain structure composed by hydrogen bonds. We studied the fluorescence of 1, 2, 3, and 5.

Porous Metal−Organic Frameworks Containing Alkali-Bridged Two-Fold Interpenetration: Synthesis, Gas Adsorption, and Fluorescence Properties

Solvothermal reactions of Zn(NO3)2·6H2O and alkali (Na, K) chloride with the trigonal-planar ligand benzene-1,3,5-tribenzoic acid (H3BTB) gave rise to two new crystalline porous metal−organic frameworks (MOFs), [Zn3Na2O(BTB)2(DMF)2](DMF)(H2O) and [Zn2K3(BTB)2(HCOO)(DMF)3](DMF)3(H2O)2, respectively. Both phases have Zn3Na2(μ4-O) and Zn2K2(HCOO) clusters as molecular building block nodes, and they form similar alkali-bridged 2-fold interpenetrated, (3,6)-connected nets with the mineral rtl-c topology. The alkali-bridged interpenetration reduces the flexibility of their interpenetrated nets, affording permanent porosity and high thermal stability. These two MOFs also exhibit high capacities of hydrogen uptake and strong solid fluorescent emissions.

PH-dependent self-assembly of divalent metals with a new ligand containing polycarboxylate: syntheses, crystal structures, luminescent and magnetic properties

Six new coordination polymers, namely, [Cd(HL)(4,4′-bpy)(H2O)]·H2O (1), [Cd3(L)2(4,4′-bpy)3(H2O)]·2.5H2O (2), [Co(HL)(4,4′-bpy)]·H2O (3), [Co2(L)(4,4′-bpy)0.5(μ3-OH)(H2O)2]·H2O (4), [Zn(HL)(BIMB)]·2H2O (5), [Zn3(L)2(BIMB)2]·3H2O (6), where H3L = 5-(4-carboxybenzyloxy)isophthalic acid, 4,4′-bpy = 4,4′-bipyridine, BIMB = 1,4-di(1H-imidazol-1-yl)benzene, have been synthesized under hydrothermal conditions and characterized by single crystal X-ray diffraction. In complexes 1, 3 and 5, H3L ligand is partially deprotonated in the form of HL2−; while in 2, 4 and 6, it is completely deprotonated due to the influence of different pH values. Complexes 1 and 5 are 2D layer structures, the hydrogen bonds between lattice-water molecules and carboxylate groups of HL2− ligands extend the 2D layer into a 3D framework; while complex 3 is a 3D framework with α-Po topology. Complex 2 is a 3D fourfold interpenetrating (3,4,4)-connected net with (63)(62·84)(64·82) topology. Complex 4 is a twofold interpenetrating (3,8)-connected net with (43)2(46·618·84) topology. And complex 6 is a twofold interpenetrating (3,4,6)-connected net with (4·62)(64·72)(42·66·74·8·92) topology. In addition, powder X-ray diffraction and thermogravimetric analyses for 1–6, photoluminescent properties for 1, 2, 5, 6 and magnetic properties for 3, 4 are investigated in detail.

Solvothermal synthesis of two unique metal–organic frameworks: a 3-fold interpenetrating (3,4,5)-connected network and a 2-fold interpenetrating (4,5)-connected network

A solvothermal reaction of Zn(OAc)2, 4,4′-bipyridine (bpy) and tri(2-carboxyethyl)isocyanurate (H3tci) in presence or absence of NaOH leads to the generation of two novel coordination polymers, [Zn3(tci)2(bpy)1.5(H2O)2]·6H2O (1) and [ZnNa(tci)(bpy)0.5(H2O)]·2H2O (2), which feature a three-fold interpenetrating (3,4,5)-connected 3D network and a two-fold interpenetrating (4,5)-connected (43.63)(43.66.8)-fsx network, respectively.

Cu 4OCl 6(DABCO) 2]·0.5DABCO·4CH 3OH (“ MFU-5”): Modular synthesis of a zeolite-like metal-organic framework constructed from tetrahedral {Cu 4OCl 6} secondary building units and linear organic linkers

A novel metal-organic framework (MOF) based on a tetranuclear copper cluster and a linear organic ligand formulated as [Cu 4OCl 6(DABCO) 2] ·0.5DABCO ·4CH 3OH (denoted as MFU-5, MFU=Metal-Organic Framework, Ulm University; DABCO=1,4-diazabicyclo[2.2.2]octane), was prepared via solvothermal synthesis. In contrast with common MOF synthesis strategies, MFU-5 is assembled from pre-defined molecular secondary building units, i.e. {Cu 4OCl 6} moieties, which become the nodes of the coordination framework. The title compound was characterized by single crystal X-ray diffraction, variable temperature powder diffraction (VT-XRPD), thermal analysis, as well as IR- and UV/Vis spectroscopy. Crystal data for MFU-5: hexagonal, P6/ mcc (no. 192), a=25.645(9), c=17.105(11) Å, V=9742(8) Å 3, Z=12, 1690 structure factors, R[ F 2>2 σ( F 2)]=0.049. MFU-5 is a 3D metal-organic framework with 1D channels running along the c-axis hosting DABCO and methanol solvent molecules. The framework displays a zeolite-like structure constructed from mso cages, which represents the composite building units in the zeolites SSF, MSO and SZR. Two-fold interpenetration is observed between these building units. TG/DTA-MS and VT-XRPD characterization reveal a stepwise release of methanol and DABCO molecules upon heating, eventually resulting in a structural change into a non-porous material.

Unique two-fold interpenetration of 3D microporous 3d–4f heterometal–organic frameworks (HMOF) based on a rigid ligand

Six heterometal-organic frameworks, {[LnCu1.5(BPDC)3(H2O)2].mH2O}n (Ln = Gd (1, m = 4.75), Tb (2, m = 3.75), Eu (3, m = 5), Ho (4, m = 2), Yb (5, m = 2.25), BPDC = 4,4-dicarboxylate-2,2-dipyridine anion), and {[LuCu1.5(BPDC)3(H2O)1.5].2.5H2O}n (6), have been synthesized under hydrothermal conditions. The structure analyses for 1-6 reveal that the six compounds are isomorphous, belonging to the monoclinic system with space group C2/c, and display two-fold interpenetrating 3D frameworks, which are the first examples of d-f heterometal-organic frameworks based on a rigid ligand. These frameworks were further characterized by elemental analyses, TG analysis, PXRD, hydrogen adsorption and variable-temperature magnetic susceptibilities. Interestingly, hydrogen adsorption was significantly observed under the existence of the two-fold interpenetration. Magnetic investigations suggest that the ferromagnetic coupling exists between Gd3+ and Cu2+ in 1, and that the nature of the interaction between Ln3+ and Cu2+ ions in compounds 2, and 4-6 cannot be absolutely determined when MT values are reduced with decreasing temperature.

Entangled metal–organic frameworks modulated by N-donor ligands of different conformations

Based on the aromatic dicarboxylic acid and N-donor ligands with different conformations, four Zn(II) metal–organic frameworks, namely [Zn(mfda)(L1)] (1), [Zn2(mfda)2(L2)]·DMF·H2O (2), [Zn2(mfda)2(L3)(H2O)]·DMF (3) and [Zn2(mfda)2(L4)] (4) have been synthesized (mfda = 9,9- dimethylfluorene-2,7-dicarboxylate anion, L1 = 1,10-phenanthroline, L2 = 4,4′-bipyridine, L3 = 2,5-bis(4-pyridyl)-1,3,4-ocadiazole and L4 = 1,4-bis(imidazol-1-ylmethyl)benzene). Single-crystal X-ray diffraction has revealed that all compounds exhibit entangled structures. Compound 1 is composed of 1D zigzag chains that are entangled through the π–π stacking interactions to generate a three-fold interpenetrating diamond-like networks. 2 exhibits a two-fold interpenetrating (α-Po) net, which leaves 1D channels with high free volume. In 3, parallel mutual polythreadings of 2D layers are connected by hydrogen bonds into a self-penetrating framework with (44·610·7)(4·5·6)(46·52·616·73·9) topology. For 4, the interpenetrating 2D layers are connected into a self-interpenetrating net with (49·66) topology. The potential of N-donor ligands to produce interesting metal–organic frameworks is investigated. Luminescent studies show that 1–4 exhibit strong blue fluorescent emissions.

Adipato‐Bridged Copper(II) Complexes

AbstractReactions of Cu(ClO4)2·6H2O, adipic acid, and 2,2′‐bipyridine/1,10‐phenanthroline in aqueous methanolic solutions afforded four adipato‐bridged CuII complexes, {[Cu(phen)2]2(C6H8O4)}(ClO4)2 (1), {[Cu(phen)2]2(C6H8O4)}(ClO4)2·1.33H2O (2), [Cu2(phen)2(H2O)]2(C6H8O4)2(ClO4)4 (3), and {[Cu2(bpy)2(H2O)]2(C6H8O4)2}(ClO4)4·2H2O (4) (phen = 1,10‐phenanthroline, bpy = 2,2′‐bipyridine, C6H8O4 = adipate anion). The centrosymmetric adipato‐bridged dumbbell‐like dinuclear complex cations {[Cu(phen)2]2(C6H8O4)}2+ in 1 and 2, through aromatic stacking interactions, are assembled into supramolecular (4,4) networks, and twofold interpenetration of the networks completes the 3D supramolecular architectures with counterions as well as the lattice water molecules in voids. The characteristic secondary building units in 3 and 4 are the centrosymmetric double‐semi‐paddle‐wheel oftetranuclear {[Cu2(phen)2(H2O)]2(COO)4} and{[Cu2(bpy)2(H2O)]2(COO)4} clusters, respectively, which are interconnected by adipato ligands to form (4,4) networks. The resulting networks, through interlayer‐stacking interactions, are assembled into a 3D open framework with counterions as well as the lattice water molecules in channels. Magnetic studies of 3 and 4 suggest significant antiferromagnetic coupling interactions between CuII ions bridged by the syn–syn carboxylate groups, whereas weak ferromagnetic coupling is observed between two symmetry‐related copper(II) ions bridged by the μ2‐O atoms. Cyclic voltammograms of 3 and 4 exhibit similar redox behaviors and display two quasireversible couples. The thermal decompositions of 3 and 4 are also described.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Layer-pillared metal-organic framework showing two-fold interpenetration and considerable solvent-accessible channels

Via solvothermal synthesis, the self-assembly of CuCl 2, 1,4-benzenedicarboxylic acid, and N, N′-bis(4-pyridylformamide)-1,4-benzene in DMF generated a layer-pillared metal-organic coordination polymer, which affords two-fold interpenetration and considerable solvent-accessible channels where the guest water molecules reside. Further, the TG and XRD researches disclose that such interpenetrating net stabilized by H-bonds can be maintained up to 350 °C even after the release of free water molecules, and through the calcination and immersion experiments, it is suggested that the guest water molecules in the channels are reversible, which is traced by XRD and IR studies.

In situ synthesis, structural characterization and luminescent property of a novel hybrid solid with twofold interpenetrating (4,6)-connected topology [{(Cu 4I 4) 2H 2O}{Cu 6(mtz) 6}] n (Hmtz = 3,5-dimethyl-1,2,4-triazole)

A novel three-dimensional hybrid solid, [{(Cu 4I 4) 2H 2O}{Cu 6(mtz) 6}] n ( 1) (Hmtz = 3,5-dimethyl-1,2,4-triazole), was synthesized under solvothermal condition. The structure of 1 consists of four-connected Cu 4I 4 clusters and hexanuclear Cu 6(mtz) 6 rings as secondary building units (SBUs), in which Hmtz was in situ generated. The links between Cu 4I 4 clusters and hexanuclear Cu 6(mtz) 6 rings result in a two-dimensional (2D) (3,6)-connected network. These layers are further bridged by μ 2-water molecules with interesting linear coordination mode into a twofold interpenetrating (4,6)-connected topology. The fluorescence emission spectrum indicates that 1 possesses intense fluorescence property with peak at 440 nm ( λ ex = 360 nm).

A 3-D (3,5)-connected Cd II coordination framework with unique twofold interpenetrating (4·6 2)(4·6 6·8 3) network topology

Assembly of N, N′-bis(4-picolinoyl)hydrazine (H 2 L) with cadmium nitrate in the presence of dicyanamide anion (dca) affords a new coordination polymer {[Cd(H L)(dca)] · (H 2O) 0.5} n ( 1), in which the [Cd(H L)] n layers are extended by dca bridges to result in a three-dimensional (3-D) coordination framework. The network structure of 1 has unusual (3,5)-connectivity and represents a new type of (4·6 2)(4·6 6·8 3) topology. Two such identical and complementary networks are entangled to generate a twofold parallel interpenetrating supramolecular lattice.

Unusual coordination geometries of silver(I) 4,5-diazafluoren-9-one complexes

Two complexes of silver(I) with 4,5-diazafluoren-9-one (dafone) which are the first examples of Ag-dafone complexes were synthesized and structurally characterized. Crystals of [Ag(dafone) 2]NO 3 · H 2O ( 1) contain two strictly planar four-coordinate Ag(I) complexes. The silver coordination polyhedron in [Ag 2(4,4′-bpy)(dafone) 4]BF 4 ( 2) is a highly distorted tetrahedron. Its crystal structure is built by a two-fold interpenetration of identical porous networks. The unusual coordination in the two compounds (planar four-coordinate d 10 ion in 1, chelation with two long Ag–N bonds in 2 and low bond valence sums in both complexes) is in part due to the large chelate bite of dafone, and in part due to the stacking and other intermolecular interactions influencing the coordination geometry of Ag(I). This was further probed through molecular simulation of [Ag(N–N) 2] + complexes using DFT calculations.

Twofold interpenetration corrugated brick wall frameworks of 3d−4f heterometallic coordination polymers

Two 3d−4f heterometallic coordination polymers [EuCo(pydc) 3(H 2O) 3] n · 2 nH 2O ( 1) [YbCo(pydc) 3(H 2O) 3] n · nH 2O ( 2) have been hydrothermally synthesized from pyridine-2,4-dicarboxylic acid (H 2pydc). Compounds 1 and 2 possess isostructural twofold interpenetration corrugated brick wall layer structures with (6,3) topology.

Structural modulation of polythreading and interpenetrating coordination networks with an elongated dipyridyl building block and various anionic co-ligands

This work presents a series of coordination polymers with a dipyridyl-type building block bis[3,5-dimethyl-4-(4′-pyridyl)pyrazol-1-yl]methane (pypz) and different anionic co-ligands. The elongated and flexible backbone of the pypz ligand facilitates the formation of diverse entangled coordination networks, which are well regulated by the auxiliary anionic components. Generally, the anions of nitrate, chloride, and pseudohalide (such as dicyanamide, thiocyanate, and azide) display a monodentate binding mode in this system and serve as terminal pendants of the metal–pypz coordination layers. As a result, 2D → 3D polythreading architectures are mostly observed, except in the case of small chloride anion that leads to twofold parallel interpenetration of the layers. On the other hand, the aromatic dicarboxylates such as terephthalate and biphenyl-4,4′-dicarboxylate behave as rod-like linkers for the construction of diversiform 2D or 3D interpenetrated coordination networks with the aid of pypz. Besides, these crystalline materials may also be significantly affected by other assembled elements such as metal ion, solvent, and metal-to-ligand ratio.

Water nanotubes confined to nanochannels of a (10,3)-b net constructed by binary building blocks via the R22(9) synthon

A (10,3)-b framework is constructed by the reaction of [Ru(H2Biim)3](PF6)2 and trimesic acid in a ratio of 1 : 1, in which the (10,3)-b net exhibits a two-fold interpenetration featuring 1D nano-sized channels. An unprecedented water nanotube consisting of the fused (H2O)28 with a double crown fashion, anchors in the channel.

Hydrogen-bond-directing effect in the ionothermal synthesis of metal coordination polymers

Four new cobalt coordination polymers, (EMIm)[Co2(TMA-H)2(44bpy)3]Br 1, (EMIm)[Co(TMA-H)(44bpy)2](44bpy)Br 2, (EMIm)[Co(TMA)(Im-H)]3 and (EMIm)2[Co(TMA)2(TED-H2)] 4, were prepared from 1-ethyl-3-methyl imidazolium bromide (EMIm-Br). All the compounds have similar two-dimensional cobalt trimesate (TMA) coordination layers but different three-dimensional supramolecular architectures that contain one of three potentially ditopic amines, 4,4'-bipyridine (44bpy), imidazole (Im-H) and triethylenediamine (TED). Two-fold interpenetration of hydrogen-bonding networks was found for 1, 2 and 4. The coordination layers of 1 and 2 are neutral while 3 and 4 have anionic molecular assemblies. The use of organic amines, that act as supramolecular bridging ligands, introduces hydrogen-bond-directing effects in the ionothermal synthesis of metal coordination polymers. Hydrogen bonding helps to align the packing between the coordination layers and control the formation of 3D supramolecular networks. In 1, hydrogen bonds between the ionic species within the channels direct the alignment of non-directional electrostatic interactions between EMIm+ and Br(-) ions, which is a rare case of a hydrogen-bond-templating effect of ionic liquids in ionothermal synthesis.

Tuning framework formation by flexible ligand elongation and second ligating spacer variation: increasing dimensionality and macrocycle size

An investigation on the dependence of the framework formation of coordination polymers is reported based on the self-assembly of copper(I) halide or pseudohalide and two relating nitrogen-containing heterocyclic thioether ligands, L1 and L2 [L1 = bis(2-pyrimidinylthio)methane, L2 = 1,2-bis(2-pyrimidinylthio)ethane]. Four new metal–organic frameworks, namely [Cu2I2(L1)2]n (1), [CuCN(L1)]n (2), [Cu2I2(L2)2]n·nL2 (3) and [CuCN(L2)]n (4) have been synthesized and characterized by X-ray crystallography. Structural diversities of these frameworks can be adjusted by elongation of flexible dithioether ligands and the selection of second ligating spacers, resulting in increasing structural dimensionality from a 1D linear chain (1), 2D layers (2,3) to a 3D diamondoid network (4). There exist fused macrocyclic rings with increasing sizes in these frameworks, ranging from 16-, 22-, 40- to 42- membered rings, respectively. The repeating “square” 40-membered macrocycle [Cu6I2(L2)4] in 3 is so large that two free L2 molecules occupy the voids of the macrocycle, stabilizing the channel-like assembly through intermolecular N⋯S interactions between the pyrimidyl rings of the L2 guest and the macrocycle-based host, whereas large macrocycles lead to two-fold interpenetration of the diamondoid nets of 4. Complexes 1–4 all show yellow photoluminescence in the solid state at room temperature.

Structure diversity and anion exchange property of zinc(II) coordination polymers with flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene

Flexible tripodal ligand 1,3,5-tris(imidazol-1-ylmethyl)benzene (L) was used to react with various zinc(II) salts ZnX [X = (BF 4) 2, SO 4, Cl 2, Br 2, I 2] to afford a series of coordination polymers with different structures. {[Zn(L) 2](BF 4) 2} n ( 1) has an infinite 2D cationic double layered structure, while {[Zn 4(L) 3(SO 4) 4] · 9H 2O} n ( 2) possesses a 3D framework structure with two different kinds of channels. The structure of [Zn 3(L) 2Cl 6] n ( 3) is 2D network and the one of {[Zn 3(L) 2Br 6] · CH 3OH} n ( 4) is an infinite 1D zigzag chain in a plywood-like stacking fashion. {[Zn(L)I]I} n ( 5) has 2D network structure which is further linked by hydrogen bonds to give rise to a fascinating 3D interlocked framework with twofold interpenetration. The results demonstrated that the counteranions have drastic effects on the structure of the coordination polymers. On the other hand, the flexible ligand L acts as a three-connecting node to connect three zinc(II) centers with different conformations. In 1 and 5, L has cis, cis, cis-conformation, while in 2, it adopts cis, trans, trans-conformation. It is interesting that two different conformations ( cis, cis, cis and cis, trans, trans) of L coexist in 3 and in the case of 4, the ligand L adopts a special trans-conformation. The results attest that the flexible ligand L can adopt different conformations to form complexes with varied structures. In addition, the uncoordinated tetrafluoroborate anions in 1 can be exchanged by nitrate or nitrite anions, which mean that 1 has anion exchange property.

(6,3)-Honeycomb Structures of Uranium(VI) Benzenedicarboxylate Derivatives: The Use of Noncovalent Interactions to Prevent Interpenetration

Four two-dimensional coordination polymers containing the uranyl cation (UO2(2+)), (NH4)UO2(BDC)1.5 . 2.5H2O (1), KUO2(NDC)1.5 . 2H2O (2), [C(NH2)3]UO2(NDC)1.5 . 2H2O (2b), and UO2(HBDC-Br)2 (3) (BDC = 1,4-benzenedicarboxylate, NDC = 1,4-naphthalenedicarboxylate, BDC-Br = 2-bromoterephthalate) have been synthesized by hydrothermal reactions. Compounds 1-2b have the same honeycomb (6,3) net but with two-fold interpenetration in 1 and without interpenetration in 2 and 2b. The use of 2-bromoterephthalate yields compound 3 with a (4,4) net. The structures of 2 and 2b show that the interpenetration can be prevented by the addition of a bulky substituent to the ligand. Maintaining the desired topology, however, requires a careful choice of the substituent group. Compounds 1, 2, and 2b have a similar structural arrangement to that of benzenetricarboxylic acid (trimesic acid, H3BTC). In H3BTC, the six rings are formed by hydrogen bonding and the interpenetration is more complex than that in 1. Crystal data: 1, triclinic, space group P, a = 10.453(8) A, b = 12.316(9) A, c = 13.441(10) A, alpha = 78.49(1) degrees , beta = 82.17(1) degrees , gamma = 85.57(1) degrees , and Z = 4; 2, monoclinic, space group C2/c, a = 12.7795(9) A, b = 19.728(1) A, c = 15.379(1) A, beta = 92.247(1) degrees , and Z = 8; 2b, monoclinic, space group C2/c, a = 12.7214(8) A, b = 19.645(1) A, c = 17.065(1) A, beta = 98.896(1) degrees , and Z = 8; 3, monoclinic, space group P21/c, a = 7.873(5) A, b = 18.358(14) A, c = 6.893(5) A, beta = 115.96(2) degrees , and Z = 2.