3D Parallel Polycatenation Research Articles

Structure-Directing Effects of Counterions in Uranyl Ion Complexes with Long-Chain Aliphatic α,ω-Dicarboxylates: 1D to Polycatenated 3D Species.

Nine uranyl ion complexes were synthesized under (solvo-)hydrothermal conditions using α,ω-dicarboxylic acids HOOC-(CH2) n-2-COOH (H2C n, n = 6-9) and diverse counterions. Complexes [PPh4][UO2(C6)(NO3)] (1) and [PPh4][UO2(C8)(NO3)] (2) contain zigzag one-dimensional (1D) chains, with further polymerization being prevented by the terminal nitrate ligands. [PPh3Me][UO2(C7)(HC7)] (3) crystallizes as a 1D polymer with a curved section, with hydrogen bonding of the uncomplexed carboxylic groups giving rise to formation of 3-fold interpenetrated two-dimensional (2D) networks. [PPh4][H2NMe2][(UO2)2(C7)3] (4) and [PPh3Me]2[(UO2)2(C8)3] (5) contain 1D chains, either ladder-like or containing doubly bridged dimers, while [PPh3Me]2[(UO2)2(C9)3]·2H2O (6) displays interdigitated, strongly corrugated honeycomb 2D nets. Ladder-like 1D polymers in [Cu( R,S-Me6cyclam)][(UO2)2(C7)2(C2O4)]·4H2O (7) are associated into layers by the hydrogen bonded counterions, whereas the [Ni(cyclam)]2+ moieties are part of the 2D polymeric arrangement in [(UO2)2(C7)2(HC7)2Ni(cyclam)]·2H2O (8) because of axial coordination of the nickel(II) center, with hydrogen bonding mediated by water molecules generating a three-dimensional (3D) net. [(UO2)2K2(C7)3(H2O)]·0.5H2O (9) contains convoluted uranyl dicarboxylate 2D subunits, which generate a 3D framework through 2D → 3D parallel polycatenation similar to that previously found in [NH4]2[(UO2)2(C7)3]·2H2O; further linking of these subunits is provided by bonding of the potassium cations to carboxylate and uranyl oxido groups. The solid-state emission spectra of complexes 1-6 and 9 display maxima positions typical of hexacoordinated uranyl carboxylate complexes, but uranyl luminescence is quenched in 7. A solid-state photoluminescence quantum yield of 11.5% has been measured for complex 1, while those for compounds 3-6 and 9 are in the range of 2.0-3.5%.

Construction of Cd(II) coordination polymers from a fluorene-based bisimidazole ligand and polycarboxylic acids: syntheses, structures and properties

Based on a fluorene-based bisimidazole ligand and polycarboxylic acids, six coordination polymers, namely [Cd2(bpdc)2(bief)2]∙xsolvent (1), [Cd(sdc)(bief)] (2), [Cd(odc)(bief)]∙H2O (3), [Cd2(1,4-ndc)2(bief)2]∙H2O (4), [Cd2(1,4-ndc)2(bief)2]∙3H2O (5) and [Cd(tdc)(bief)(H2O)] (6), have been synthesized and structurally characterized. Compound 1 exhibits a 2-fold interpenetrated sql net. Compound 2 and 3 present the 2D → 3D parallel polycatenation of sql net. Compound 4 features a 2D → 3D parallel polycatenation of binodal 4,6L56 net. Compound 5 exhibits an eight-connected tsi framework. Compound 6 exhibits an eight-connected bcu framework. Their thermal stabilities and photochemical properties have also been studied.

2D → 3D interlocking Zn(II) arrays directed by uncoordinated groups: Fluorescent behaviors, recycling and enhancements of photocatalytic properties

To investigate the effect of the uncoordinated groups of “V”-type dipyridylamide on the interlocking arrays of Zn(II) coordination polymers, [Zn(L1)(1,4-bdc)]·H2O (1) and [Zn(L2)(1,4-bdc)]·H2O (2) [L1 = N,N′-bis(pyridin-3-yl)-5-hydroxybenzene-1,3-dicarboxamide, L2 = N,N′-bis(pyridine-3-yl)-5-methylbenzene-1,3-dicarboxamide, 1,4-H2bdc = 1,4-benzenedicarboxylic acid] have been hydrothermally synthesized and structurally characterized by IR, TG and X-ray single-crystal diffraction. Complex 1 is a 2D 63 network based on [Zn(1,4-bdc)] zigzag chains and [Zn(L1)]2 loops, which is further extended into 2D → 3D parallel polycatenation array. Complex 2 features a 2D (4,4) network derived from [Zn(1,4-bdc)] zigzag chains and [Zn(L1)] helixes, which is further extended into 2D → 3D inclined interpenetration array. The effect of the uncoordinated groups of “V”-type dipyridylamide on the structures of the title complexes was discussed. The fluorescent behaviors of 1–2 in aqueous solutions with Fe3+, Co2+, Ni2+, Cu2+, Zn2+ were investigated. The photocatalytic properties of complexes 1–2, Ag loaded CPs composite materials (Ag@1–2) and Fe3+-functionalized composite materials (Fe3+@1–2) for the degradation of methylene blue (MB) under ultraviolet light irradiation have been investigated.

Three d10 coordination polymers assembled from 3,5-bis(imidazole-1-yl)pyridine and different polycarboxylates: Syntheses, structures and luminescence properties

Three novel Zn(II)/Cd(II) coordination polymers, [Cd2(bip)2(m-bdc)2(H2O)2·3H2O]n (1), [Zn2(bip)2(p-bdc)2·2.5H2O]n (2) and [Zn(bip) (p-bdc)·3H2O]n (3), where bip = 3,5-bis(imidazole-1-yl)pyridine, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, have been successfully synthesized under solvothermal conditions. The linkage of different ligands with Cd(II) ions in compound 1 affords a (3,5)-connected layer. Furthermore, 2D→3D parallel polycatenation occurs wherein the layers are polycatenated with the adjacent two parallel layers to form a 3D framework. In 2 and 3, the polycarboxylates act as pillars to combine the metal-bip chains, yielding the layered structures. These 2D networks are extended to the final 3D supramolecular architectures by π-π stacking interactions. The results show that bip can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescent properties of 1–3 in the solid state at room temperature have been investigated.

Structural control and magnetic properties of three Co(II) coordination polymers based on 6-(3,5-dicarboxylphenyl)nicotinic acid

Three coordination polymers (CPs) based on 6-(3,5-dicarboxylphenyl)nicotinic acid (H3DCPN) and N-donor linkers, {[Co(HDCPN)(bbib)(H2O)]·2H2O}n (1), [Co(HDCPN)(bbib)]n (2), and {[Co(HDCPN)(bpy)0.5(H2O)]·H2O}n (3) (bbib=1,4-bis(benzimidazo-1-ly)benzene, bpy=4,4′-bipyridine), were synthesized under solvothermal conditions. Single-crystal X-ray diffraction analysis reveals that complexes 1–3 are 3D supramolecular structures. Complexes 1 and 2 display 2D 4-connected sql networks, and complex 3 shows a 2D (3,4)-c network, which are all further packed into 3D supramolecular structures by hydrogen bonds. It is noteworthy that the adjacent layers interpenetrate with each other to generate 2D+2D→2D network in complex 1, and complex 3 possesses an intriguing 2D+2D→3D parallel polycatenation architecture. The different structures for complexes 1 and 2 can be attributed to temperature-dependent structural variation. Furthermore, the magnetic properties of complexes 2 and 3 have been also investigated, and both of them exhibit weak antiferromagnetic coupling interactions.

Unusual self-penetrating and polycatenated coordination polymers based on the semi-rigid V-shaped ligand 4-(1-(4-(2H-tetrazol-5-yl)benzyl)-1H-pyrazol-3-yl)pyridine

Self-assembly of d10 metal salts with a semi-rigid V-shaped N-containing ligand affords two entangled coordination frameworks, namely [Zn2(bdc)1.5(tbpp)] (1) and [Cd(tbpp)2(H2O)]·H2O (2) (Htbpp=4-(1-(4-(2H-tetrazol-5-yl)benzyl)-1H-pyrazol-3-yl)pyridine, H2bdc=1,4-benzenedicarboxylate acid). 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 a (3,6)-connected 3D self-penetrating network with an unprecedented (4.62)(43.67.74.8) topology. Compound 2 is the first example of (2D→3D) parallel polycatenation of 44-sql net with double edges. Additionally, the photoluminescence properties of compounds 1 and 2 were studied.

Ancillary ligand-assisted assembly of C3-symmetric 4,4′,4″-nitrilotribenzoic acid with divalent Zn2+ ions: Syntheses, topological structures, and photoluminescence properties

4,4′,4″-nitrilotribenzoic acid (H3L), a C3-symmetric ligand, was found to self-assemble into two polymorphs driven by intermolecular hydrogen-bonding interactions. Reactions of this ligand with Zn2+ under solvothermal conditions resulted in four new coordination polymers bearing interesting structural motifs: [Zn2(L)2(py)2]·2(H2NMe2)+·DMF·2H2O (1), [Zn2(L)(H2L)(bipy)]·1.5H2O·Guest (2), [Zn2(L)2(bipy)]·2(H2NMe2)+·2DMF (3), and [Zn3(L)2(bpa)]·2H2O·Guest (4) (H3L=4,4′,4′′-nitrilotribenzoic acid, DMF=dimethylformamide, py=pyridine, bipy=4,4′-bipyridine, bpa=1,2-bis(4-pyridyl)diazene). Single-crystal structural analysis revealed that compound 1 exhibits a rare example of twofold interpenetrating anionic 3D (3,3)-net framework containing helical channels, whereas in 2, the 3D pillar-layer structure generated from bipy-pillared Zn2(L)(H2L) layer is further reinforced by intermolecular hydrogen bonding among pairs of free –COOH units. Compound 3 shows an interesting entangled architecture of 2D→3D parallel polycatenation consisting five-coordinated Zn2+ ions. Compound 4 displays a 3D pillar-layer framework with trimeric Zn3(CO2)6 serving as secondary building unit (SBU). The syntheses, structures, thermal stabilities, powder X-ray diffractions and solid-state photoluminescence properties for these crystalline materials have been carried out. In addition, supramolecular assembly of H3L under solvothermal conditions will also be addressed.

Luminescent and porous zinc complex with 2D → 3D parallel polycatenation based on a new rigid V-shaped pyridyl ligand

Entangled coordination polymers have attracted considerable interest due to their novel structures and potential applications. In this paper, one new 2D→3D porous zinc coordination polymer {[Zn2(DPDBT)2(OBA)2](H2O)3}n (1) with parallel polycatenation was synthesized under solvothermal conditions based on 2,8-di(pyridin-4-yl)dibenzo[b,d]thiophene (DPDBT) ligand. In addition, complex 1 exhibits interesting solid-state photoluminescence and high thermal stability.

Two pairs of isomorphism and two 3D metal–organic frameworks based on a star-like ligand tri(4-pyridylphenyl)amine

Six novel metal–organic frameworks (MOFs) have been synthesized in this paper, which are based on a N-centered ligand TPPA, namely, [Cd(TPPA)(fuma)]n (1), {[Zn(TPPA)(suc)]·5(H2O)·DMA}n (2), [Co(TPPA)(bhf)]n (3), [Zn(TPPA)(bhf)]n (4), [Co(TPPA)(oba)]n (5), and [Cd(TPPA)(oba)]n (6), [TPPA = tri(4-pyridylphenyl)amine, H2fuma = fumaric acid, H2suc = succinic acid, H2bhf = 2,2′-bis(4-carboxyphenyl)hexafluoropropane, H2oba = 4,4′-oxybis(benzoic acid)]. Compound 1 reveals a 4-fold interpenetrating 3D framework with AFUQOH topology. Compound 2 reveals a 2-fold interpenetrating 3D network with large void space (up to 37.6%). Compounds 3 and 4 are isomorphic 2D networks. Different from compounds 3 and 4, compounds 5 and 6 show 2D → 3D parallel polycatenation of undulated square layers. In addition, photochemical properties of compounds and the ligands in the solid state have been studied.

A series of metal–organic frameworks based on a semi-rigid bifunctional ligand 5-[(1H-1,2,4-triazol-1-yl)methoxy] isophthalic acid and flexible N-donor bridging ligands

Eight metal–organic frameworks, namely, [Co2(L)2(biim-4)(H2O)2] (1), [Mn2(L)2(biim-4)(H2O)2] (2), [Mn2(L)2(btd)] (3), [Ni2(L)2(biim-4)(H2O)2]·4H2O (4), [Cu2(L)2(biim-4)(H2O)]·2H2O (5), [Cu2(L)2(btd)]·4H2O (6), [Zn2(L)2(biim-4)]·4H2O (7) and [Zn2(L)2(biim-4)]·H2O (8), where H2L = 5-[(1H-1,2,4-triazol-1-yl)methoxy] isophthalic acid, biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), and btd = 1,10-bis(1,2,4-triazol-1-yl)decane, have been synthesized and characterized. Compounds 1 and 2 are isostructural and display three-dimensional (3D) (4,5)-connected nets with the same (42·64)(42·67·8) topology. Compound 3 possesses a 3D (4,5)-connected framework with (43·63)(43·66·8) topology. Compound 4 shows a two-dimensional (2D) trinodal (3,4)-connected network with a topology of (4·52)2(54·82)(42·52·72) and a vertex symbol of (4·5·5)(5·5·5·5)(4·4·5·5), which is extended by hydrogen bonding interactions into a 3D supramolecular architecture. Compounds 5 and 6 furnish 3D (3,4)-connected nets with (4·6·8)(4·62·83) and (4·82)(4·82·103) topologies, respectively. Compounds 7 and 8 were prepared by using the same raw materials at different temperatures. Compound 7 has a 2D → 3D parallel polycatenation formed through bilayers. Compound 8 features a 3D (3,4)-connected net with (6·102)(62·104) topology. In addition, photoluminescent properties for compounds 7 and 8 are discussed.

Hydrothermal Synthesis, Crystal Structure and Spectroscopic Characterization of a Novel 2D → 3D Parallel Polycatenated Coordination Framework [Cd(cmb)(bix)] n

A novel entangled coordination polymer [Cd(cmb)(bix)] n (1) [H2cmb = 2,2′-(2-(carboxymethoxy)benzoic acid), bix = 1,4-bis(imidazol-1-ylmethyl)benzene], has been synthesized by hydrothermal reaction of Cd(Ac)2·2H2O, bix and H2cmb, and characterized by elemental analysis, IR spectra, PXRD, and single-crystal X-ray diffraction. The structure determination reveals that the complex 1 shows a new 2D → 3D parallel polycatenation framework based on highly undulating 2D 44 -sql layers, in which each layer is polycatenated with adjacent two others (one above and one below, DOC = 4) which have parallel but not coincident mean planes. Moreover, the thermal stability and photoluminescence property of 1 were also discussed. A novel 2D → 3D parallel polycatenated coordination polymer [Cd(cmb)(bix)] n (1), based on highly undulating 2D 44 -sql layers, has been hydrothermally synthesized and characterized. Moreover, the thermal stability and photoluminescence property of 1 were also investigated.

Topological evolution and photoluminescent properties of a series of divalent zinc-based metal–organic frameworks tuned via ancillary ligating spacers

The combination of divalent zinc ions, 4-(4-carboxybenzamido)benzoic acid and exo-bidendate bipyridine ligands gave rise to a series of new MOFs: [ZnL(bipy)]·DMF·H2O (1), [ZnL(bpe)]·1.5H2O (2), [ZnL(bpa)]·4H2O (3) and [ZnL(bpp)]·1.75H2O (4) (MOF=metal-organic framework, bipy=4,4′-bipyridine, bpe=trans-1,2-bis(4-pyridyl)ethylene, bpa=1,2-bis(4-pyridinyl)ethane, bpp=1,3-bis(4-pyridinyl)propane, H2L=4,4′-(carbonylimino)dibenzoic acid). Fine tune over the topology of the MOFs was achieved via systematically varying the geometric length of the second ligating bipyridine ligands. Single-crystal X-ray analysis reveals that complex 1 has a triply interpenetrated three-dimensional (3D) framework with elongated primitive cubic topology, whereas isostructural complexes 2 and 3 each possesses a 6-fold interpenetrated diamondiod 3D framework. Further expansion of the length of the bipyridine ligand to bpp leads to the formation of 4, which features an interesting entangled architecture of 2D→3D parallel polycatenation. In addition, the thermogravimetric analyses and solid-state photoluminescent properties of the selected complexes are investigated.

Positional isomeric and substituent effect on the assemblies of a series of d10 coordination polymers based upon unsymmetric tricarboxylate acids and nitrogen-containing ligands

Seven novel compounds, {[Zn2(L1)2]·2H2N(CH3)2·DMF}n (1), {[Cd2(L1)2]·2H2N(CH3)2·DMF}n (2), [Zn(HL2)(bpe)]n (3), [Zn2(HL2)2(bpea)2(H2O)]n (4), {[Cd2(HL2)2(bpe)(H2O)2]·2H2O}n (5), {[Cd2(HL2)2(bpea)(H2O)2]·2H2O}n (6) and {[Zn(HL3)(bpea)]·2H2O}n (7), were constructed based on three unsymmetrical tricarboxylate ligands and nitrogen-containing ligands (H3L1 = biphenyl-3,4′,5-tricarboxylic acid, H3L2 = biphenyl-3,3′,5-tricarboxylic acid, H3L3 = biphenyl-3-nitro-5,3′,5′-tricarboxylic acid, bpe = 1,2-bi(4-pyridyl)ethylene, bpea = 1,2-bi(4-pyridyl)ethane) under hydrothermal conditions. The positional isomeric and substituent effects of these ligands lead to fascinating structures. Compounds 1 and 2 afford 3D (3,6)-connected (4.62)2(42.610.83) rutile topologies based on dinuclear M2(CO2)2 SBUs. Compounds 3 and 4 are 4-connected diamondoid nets, which exhibit unusual roto-translational [2 + 2]-fold and common 4-fold interpenetration due to the different weak interactions among each interpenetrating motif, respectively. Compounds 5 and 6 are isostructural, both presenting 2D unique undulated (3,4)-connected (42.6)(42.63.8) topologies. Compound 7 possesses a 2D → 3D parallel polycatenation framework composed of (4,4) undulated sheets. The effects of the positions of the carboxylate groups and the substituent groups on the aromatic rings, the flexibility of the N-containing coligands as well as the coordination geometry of the metal centers are discussed in details. The fluorescence properties and thermal stability of the ligands and compounds have also been performed.

Tuning Structural Topologies of Three Photoluminescent Metal–Organic Frameworks via Isomeric Biphenyldicarboxylates

Three new cadmium compounds, [Cd(2,4'-bpdc)(bib)(0.5)] (1; 2,4'-bpdc = biphenyl-2,4'-dicarboxylate and bib = 1,4-bis(2-methyl-imidazol-1-yl)butane), {[Cd(2)(3,4'-bpdc)(2)(bib)(1.5)(H(2)O)](n)·H(2)O}(n) (2; 3,4'-bpdc = biphenyl-3,4'-dicarboxylate), and [Cd (4,4'-bpdc)(bib)] (3; 4,4'-bpdc = biphenyl-4,4'-dicarboxylate), have been successfully synthesized by the assembly of Cd(2+) ions, bib ligands, and isomeric bpdc ligands, respectively. This paper presents a comparative study on the tuning of structural topologies using three isomers of biphenyldicarboxylates as bridging ligands. Compound 1 based on 2,4'-bpdc features a three-dimensional (3D) framework with 6-connected mab topology. Compound 2 based on 3,4'-bpdc is another 3D framework, but it possesses a rare 3-fold interpenetrating 4,6-connected fsh net, while compound 3 based on linear 4,4'-bpdc shows unusual 2D → 3D parallel polycatenation of (4,4) layers. Furthermore, the luminescent properties of three compounds are investigated in the solid state.

Entangled coordination polymers with mixed N- and O-donor organic linkers: A case of module-matching priority

A series of four coordination polymers showing entangled architectures based on cobalt and mixed N-donor/O-donor ligands, namely [Co(4,4'-BPIPA)(TP)]·2DMF (1), [Co(4,4'-BPIPA)(2,6-NDC)(DMF)]·DMF (2), [Co(4,4'-BPIPA)(2,6-NDC)]·2DMF (3) and [Co(4,4'-BPIPA)(4,4'-BPDC)]·2DMF (4) (4,4'-BPIPA = N,N'-bis-4-pyridinyl-isophthalamide, TP = terephthalic acid, 2,6-NDC = 2,6-naphthalenedicarboxylic acid, 4,4'-BPDC = 4,4'-biphenyldicarboxylic acid), have been synthesized under solvothermal conditions. Complex 1, containing 4,4'-BPIPA and relatively short dicarboxylate ligands (TP), exhibits two-dimensional (2D) two-fold interpenetration of double wavy 4(4)-sql nets. Complex 2 displays interesting 2D→3D parallel polycatenation of undulated 2D 4(4)-sql layers built by 4,4'-BPIPA and moderate dicarboxylate ligands (2,6-NDC). Complexes 3 and 4, although constructed of dicarboxylate ligands with different lengths (moderate 2,6-NDC and long 4,4'-BPDC), possess similar 3-fold interpenetration of identical self-catenated single nets with 6(5)·8-mok topologies. It has been found that the length of the dicarboxylate ligands plays a key role of module-matching in the self-assemblies of complexes 1-4. Moreover, the effect of the conformations of 4,4'-BPIPA, which can be controlled by tuning reaction temperatures, is also discussed.

Two Unprecedented Entangled Metal–Olsalazine Complexes with Coexistence of 2D → 3D Polycatenation and meso‐Helix

AbstractRational self‐assembly of the anti‐inflammatory drug olsalazine (H4osa) with a cobalt salt in the presence of linear bidentate ligands yields two novel metal–drug complexes[Co(H2osa)(bpp)] (1) and [Co2(osa)(bpy)2(H2O)4] (2) [bpp = 1,3‐bis(4‐pyridyl)propane, bpy = 4,4′‐bipyridine]. Their structures were determined by single‐crystal X‐ray diffraction and further characterized by elemental analysis, IR spectroscopy, X‐ray powder diffraction, and thermogravimetric analysis (TGA). Compound 1 displays a new 2D → 3D parallel polycatenation of undulating (4,4) layers, whereas 2 exhibits an unusual 2D → 3D inclined polycatenation of (6,3) layers. To the best of our knowledge, they represent the first examples of metal–drug complexes that have both polycatenane and meso‐helix characteristics. The magnetic properties of 1 and 2 have been studied by measuring their magnetic susceptibility in the temperature range of 2–300 K.

From 2D → 3D inclined polycatenation to 2D → 3D parallel polycatenation: a central metal cationic induce strategy

Two interesting entangled architectures, based on 44-sql subunits, showing interesting structure variation from 2D → 3D inclined polycatenation to 2D → 3D parallel polycatenation, are reported. The coordination geometries of the central metal cations are found very important in directing assemblies of the polycatenated networks.

Solvent and temperature influence structural variation from nonporous 2D → 3D parallel polycatenation to 3D microporous metal–organic framework

Three novel complexes constructed from the same initial materials, exhibiting the variation of architectures from nonporous 2D → 3D parallel polycatenation based on highly undulating (4,4) nets to 3D microporous pillar-layered network through influencing the interpenetration, have been successfully synthesized under different reaction conditions.

Five 3D metal–organic frameworks constructed from V-shaped polycarboxylate acids and flexible imidazole-based ligands

Five new metal–organic frameworks, namely, Cd2(SA)(obix) (1), Zn2(SA)(bimb) (2), Cd(SDBA)(timb)·3H2O (3), Co(SDBA)(bimb) (4), and Co(SDBA)(obix) (5) (H4SA = 3,3′,4,4′-diphenylsulfonetetracarboxylate acid, H2SDBA = 4,4′-dicarboxybiphenyl-sulfone, obix = 1,2-bis(imidazol-1-ylmethyl)benzene, timb = 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trimethylbenzene and bimb = 4,4′-bis(imidazol-1-ylmethyl)biphenyl), have been synthesized under hydrothermal conditions by employing mixed ligands of various imidazole-based ligands with H4SA or H2SDBA. The networks exhibit a variety of topologies and coordination modes at the metal centers. Complex 1 features a novel (5,7)-connected seh net consisting of one-dimensional inorganic chains which are bridged by carboxylate groups of SA4− ligands, whereas complex 2 possesses a unique 4-connected 3D framework with (62·82·102)(62·83·10)(62·83·9) topology. Complex 3 exhibits a rare (3,5)-connected 3D framework with gra topology. Complex 4 shows 4-connected MOFs with (65·8) CdSO4-type topology, while in 5, the SDBA and obix ligands linked the Co(II) atoms into a deeply corrugated 2D sheet. The corrugated 2D sheets polycatenate each other in a parallel manner yielding a rare 2D → 3D parallel polycatenation net. The photoluminescence properties of 1–3 were studied in the solid state at room temperature. Moreover, the second-harmonic-generation (SHG) activity of 2–5 have also been investigated.

A (3,4)-connected two-dimensional copper coordination polymer with a 2D→3D polycatenation network

The reaction of 1,3,5-tri(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene (ttmb) with CuCl 2 yields a coordination polymer [Cu 3 (ttmb) 2 (H 2 O) 6 Cl 6 ] n ·3 n H 2 O ( 1 ). The flexible ligand ttmb shows the cis,cis,cis -conformation and a tri-monodentate coordination mode in 1 . Each ttmb links three Cu(II) atoms to form an undulated (3,4)-connected two-dimensional network. Each undulated two-dimensional network polycatenates other two identical networks, thus giving a rare (2D → 3D) parallel polycatenation network in 1 . The thermal stability of compound 1 was studied.