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Owing to perovskite possessing the outstanding optoelectronic properties, perovskite-based solar cells show prominent performance. The stability of perovskite-based solar cells hampers the progress of commercialization, so it is important to understand the microstructure mechanism of perovskite degradation under the humidity and oxygen environmental conditions. In this study, a meaningful Debye-type dielectric relaxation was observed under water vapor and oxygen co-treatment conditions. Interestingly, the relaxation was not observed under water vapor or oxygen treatment individually. This new dielectric relaxation is identified as a direct result of dipole jump, and its activation energy was measured to be 630 ± 6 meV. According to photoelectron spectroscopy and 13C nuclear magnetic resonance data, we suggest that the dipoles are formed by CH3NH3+ (MA+) and superoxide (O2-), which originate from the distorted crystal lattice and water vapor-weakened hydrogen bonds of Pb-I cages. In addition, the activation energy fitted by dielectric relaxation might be the energy of ion migration. This study contributes to understanding the mechanism of perovskite degradation from the view of microstructure relaxation and evolution, and also provides a method for the analysis of ion migration energy.

Three new isostructural 3D lanthanide metal-organic frameworks (Ln-MOFs), {H[LnL(H2 O)]⋅2 H2 O}n (1-Ln) (Ln=Eu3+ , Gd3+ and Tb3+ ), based on infinite lanthanide-carboxylate chains were constructed by employing an ether-separated 5,5'-oxydiisophthalic acid (H4 L) ligand under solvothermal reaction. 1-Eu and 1-Tb exhibit strong red and green emission, respectively, through the antenna effect, as demonstrated through a combination of calculation and experimental results. Moreover, a series of dichromatic doped 1-Eux Tby MOFs were fabricated by introducing different concentrations of Eu3+ and Tb3+ ions, and they display an unusual variation of luminescent colors from green, yellow, orange to red. 1-Eu with channels decorated by ether O atoms and the open metal sites displays good performance for CO2 capture and conversion between CO2 and epoxides into cyclic carbonates.

The first isolable Ge5-spiropentadiene 1 was synthesized via the reduction of (iPr3Si)2NGeCl (3) with potassium. The crystal structure of 1 reveals a spirocyclic Ge5 skeleton containing two Ge-Ge double bonds (avg. 2.34 A), which are fettered in two Ge3 rings with a dihedral angle of 70.193°. The DFT calculations and orbital analysis show that the σ-delocalization of the Ge5 skeleton and the 2π-delocalized aromatic Ge3 rings enhance the stability of molecule 1.

A series of new alkaline earth-metal organic frameworks (AE-MOFs), i.e. {[Mg2(μ6-L)(μ2-OH2)(H2O)4]·DMF}n (1), [Ca2(μ10-L)(EtOH)]n (2), [Sr(μ6-H2L)(MeOH)]n (3) and {[Ba1.5(μ5-H2L)(μ4-H3L)(H2O)3]·2(H2O)}n(4) were synthesized under solvothermal reaction by employing a symmetrical V-shaped multicarboxylic acid ligand H4L (H4L = 5,5′-oxydiisophthalic acid), resulting in versatile coordination modes as well as various topologies. 1 forms a uninodal 4-connected (66)-dia 3D topology based on dinuclear Mg2(COO)2(μ2-OH2) clusters. 2 displays an unprecedented 3-nodal (5,5,10)-connected 3D net with (424·621)(48·62)2 topology based on 1D [Ca(COO)]n chains and dinuclear Ca2(COO)2 clusters. 3 indicates a uninodal 6-connected 3D net with (410·65)-sma topology based on 1D [Sr(COO)]n chains. 4 features a new 4-nodal (4,5,6,6)-connected net with (43·63)2(46·64)2(46·68·8)(46·69)2 topology based on two types of 1D chains. 1-4 show solid-state fluorescent properties at ambient temperature. Especially, 1 and 2 have multiresponsive recognition of Fe3+ and Pb2+ ions, Fe3+ and Cu2+ ions, respectively, while 3 and 4 show single selective detection for Fe3+ ion, signifying that they could be potential fluorescent sensors for specific heavy metal ions in water system. The sensing mechanism has also been discussed in detail.

In order to explore the metal ions-controlled syntheses of coordination polymers (CPs), the temperature and solvent ratio were fixed in the reaction processes. By selecting a series of s- and d-block metal ions, five new CPs, [ZnL0.5(H2O)2]n (1), [CoL0.5(H2O)2]n (2), [Mn(H2L)(H2O)2]n (3), [Ca(H2L)(H2O)2]n (4) and [Ba(H2L)(H2O)2]n (5), have been synthesized by employing a less-investigated oxalamide N,N′-bis(4-phthalic acid) (H4L) ligand. H4L shows very versatile coordination modes and leads to various frameworks, including isomorphous 2D grid-like layer based on M2O2 cores for 1 and 2, isomorphous 4-connected 3D PtS frameworks based on 1D [M(CO2)2]n chains for 3 and 4, and a 2D wave-like layer based on [BaO3]n chains for 5.2 and 3 reveal the antiferromagnetic and ferromagnetic properties, respectively, while 1, 4 and 5 possesses strong solid state luminescence.

Four new water-stable luminescent metal-organic frameworks (MOFs), namely {[Zn4(L)2(H2O)4(OH)2]·3NMP}n (1), {[Zn3(L)2(H2O)2]·Diox}n (2), {[Cd3(L)2 (H2O)5]·NMP·3H2O}n (3), and {[Pb3(L)2(NMP)2(H2O)]·H2O}n (4), (H3L = 5-(1-(carboxymethyl)pyrazol-3-yl)isophthalic acid; NMP = N-methyl-2-Pyrrolidoneand; Diox = 1,4-Dioxane) have been solvothermally synthesized with different solvents. The single crystal structures of 1–4 reveal that complexes 1 and 2 form the 2D (3,6)-connected kgd nets based on the tetranuclear [Zn4(μ1-COO)2(μ2-COO)4] clusters and trinuclear [Zn3(μ1-COO)2(μ2-COO)4] clusters, respectively. Complex 3 displays a 2D (3,6)-connected kgd net based on the trinuclear [Cd3(μ1-COO)4(μ2-COO)2] clusters. Complex 4 presents a 2D layer with a rod-shaped SBUs. The solid-state luminescence properties and water stability of these complexes were investigated carefully, showing that 1 displays high selectivity for Fe3+, CrO42−, and Cr2O72− via luminescence quenching effects with low detection limits. The probable quenching mechanisms have been studied in detail.

The reactions of an unexploited N,N'-5-carboxyl-1,3-phenylenebis(ethyl oxamate) (HEt2 L) ligand with different Mn2+ and Cd2+ salts under solvothermal conditions afforded four three-dimensional (3D) coordination polymers (CPs): [Mn1.5 L(H2 O)2 ]⋅H2 O (1) [Mn2 L(C2 O4 )0.5 (NMP)(H2 O)] ⋅ NMP (2), [Cd1.5 L(H2 O)2.5 ] ⋅ H2 O (3) and [Cd2 L(C2 O4 )0.5 (H2 O)3 ] ⋅ H2 O (4) (NMP=N-methyl pyrrolidone). L, generated by the in-situ hydrolysis of HEt2 L, displays four kinds of coordinating modes through oxamate and carboxylate groups as well as different syn-syn and syn-trans configurations. The resulting novel (3,4,5)-, (3,4,6)-, (4,5)- and (4,4,4,5)-connected topologies for 1-4 were formed. Among them, 1 has interesting 1D metal-oxamate zigzag chains, 2 contains 1D channels with a free void of 52.5 %, 3 consists of an unprecedented Cd-oxamate layer, 4 has a novel Cd-oxamate-oxalate chain. The antiferromagnetic interactions of 1 and 2 were observed, meanwhile 3 and 4 exhibit solid-state luminescence with the maximum emission bands at 483 and 479 nm, respectively, under an excitation of 332 nm.

To develop efficient adsorbent materials for storage and separation of C2 H2 , an unprecedented supercage MOF, [Me2 NH2 ]⋅[Zn3 (ALP)(TDC)2.5 ]⋅3.5DMF⋅2 H2 O (1) was constructed through medicinal molecule allopurinol (ALP) and S-containing 2,5-thiophenedicarboxylic acid (H2 TDC). 1 contains a novel linear trinuclear cluster that is composed by ALP and carboxylates and forms a final uncommon 5-connected yfy topological framework. The framework possesses three types of interlinked cages decorated by rich functional sites, and reveals not only high adsorption capacity for C2 H2 but also excellent selective separation for C2 H2 /CO2 and C2 H2 /CH4 at 298 K. Dynamic breakthrough experiments on C2 H2 /CO2 (1:1) mixture and C2 H2 /CH4 (1:1) mixture also demonstrated the potential of the material to separate C2 H2 from CO2 or CH4 mixtures. Molecular simulations were also studied to identify the different CO2 - and C2 H2 - binding sites in 1, such as carboxylate groups, S atoms and carbonyl groups.

Two new symmetrical tripod thioether tricarboxylic acid ligands, 1,3,5-tris(4-carboxyphenylsulfanylmethyl) benzene and 1,3,5-tris(4-carboxyphenylsulfanylmethyl)-2,4,6-trimethylbenzene (H3L and CH3-H3L) have been designed and synthesized. The reaction of two ligands with Cu2+ ions afforded two Cu-based cluster coordination polymers (CPs), [Cu3L]n (1) and {[Cu(CH3-HL)DMF]·DMF}n (2). It was interesting to note that the substituent groups on central phenyl rings in ligands caused the bend tripodal and planar geometries as well as different coordinated modes for H3L and CH3-H3L, respectively, leading to different structures of CPs 1 and 2. 1 with monovalent Cu+ ions shows a 3D layer-stacking framework with hexanuclear [Cu6(CO2)6] clusters, while 2 with divalent Cu2+ ions forms a 1D chain with dinuclear [Cu2(CO2)4] paddlewheel clusters. 1 shows strong orange fluorescence and exhibits fluorescence sensing for Cr2O42− and Fe3+ ions with good selectivity and sensitivity.

Three new coordination polymers, {[Mn3(pzbtz)2(Cl)2(H2O)2]·4H2O}n (1), {Mn2(pzbtz)(SO4)(H2O)3]·3H2O}n (2), and {[Mn3(pzbtz)3(H2O)3]·1.5DMA·2H2O}n (3), have been solvothermally synthesized with MnCl2/MnSO4 and a bitriazole ligand, 5′-(pyrazin-2-yl)-2H,4′H-3,3′-bi(1,2,4-triazole) (H2pzbtz), in different solvent systems. H2pzbtz shows different geometrical configurations and coordination modes, leading to the diverse three-dimensional (3D) frameworks of 1–3. Complex 1 contains the trinuclear Mn3(tr)4X2 (X = Cl or H2O) clusters and reveals an unobserved (3,4,8)-connected sqc929 topological framework with two types of cages. Complex 2 is a new (3,4,6)-connected network based on dinuclear Mn2(tr)2 clusters, and 3 shows an 8-connected bcu topology with a novel tetranuclear Mn4(tr)6 cluster. Complexes 1 and 2 show antiferromagnetic properties, while 3 reveals spin-canting magnetic behavior with an uncommonly high Tc around 44 K. In addition, 1 also possesses good adsorption selectivity for CO2 over CH4 and N2 and...

The use of molecular iodine to tune the electrical conductivity in metal-organic frameworks is an effective but seldom investigated strategy. Herein, the single-crystal-to-single-crystal transformation of [Co1.5 (bdc)1.5 (H2 bpz)]⋅DMF⋅4 H2 O (1) to [Co1.5 (bdc)1.5 (H2 bpz)]⋅0.5 I2 ⋅DMF (I2 @1) (H2 bdc=1,4-benzenedicarboxylic acid, H2 bpz=3,3',5,5'-tetramethyl-4,4'-bipyrazole) upon I2 loading caused a three orders of magnitude enhancement in electrical conductivity of the framework. Single-crystal X-ray diffraction revealed that I2 exists as a single molecule embedded in the channels of framework, and the C-H⋅⋅⋅I hydrogen bonds between I2 molecules and phenyl units on the porous surface of the framework were suggested to participate in n→σ* host-guest charge transfer, leading to increased electrical conductivity in I2 @1. Furthermore, 1 displayed moderate adsorption selectivity for CO2 over CH4 and N2 .

To seek novel dysprosium based single-molecule magnets, a dinuclear dysprosium complex, namely [Dy2(L)2(DBM)2(DMF)2]·2DMF (1) was successfully obtained by employing tridentate Schiff base ligand (where H2L = 2-hydroxy-N′’-(2-hydroxy-3-methoxybenzylidene) benzohydrazide), HDBM = dibenzoylmethane, DMF = dimethylformamide). Single-crystal X-ray structural analysis reveals that the key feature of 1 is neutral dinuclear complex, in which two Dy(III) ions with eight-coordinated environment are bridged by two phenoxido oxygen atoms from two Schiff base ligands. Interestingly, complex 1 could be regarded as the structurally related derivatives to our previous reported complex of [Dy2(L)2(DBM)2(DMF)2] (1a) but adding two guest DMF solvents. More importantly, the energy barrier to magnetic relaxation of 1 is slightly higher, with a value of 33 K, when compared to the corresponding complex 1a of 24 K, which provides a good example towards regulating magnetization dynamics in dinuclear dysprosium (III) single-molecule magnets by guest solvent molecules.

A new zinc(II) coordination polymer, namely [Zn(bipy)2(H2O)4]n·n(dsba) (1), has been synthesized by the mixed 4,4′-biphenyldisulfonic acid (H2dsba) and 4,4′-bipyridine (bipy) ligands with Zinc(II) salt under the common solution evaporation method. The results of the X-ray crystal diffraction analysis show that complex 1 belongs to the monoclinic system with P21/c space group. The unit cell constants of complex 1 are a = 9.2579 A, b = 12.2016 A, c = 14.447 A, α = γ = 90˚, β = 93.476˚. Complex 1 exhibits a three-dimensional supramolecular network based on the discrete structure by utilizing various H-bonded interactions. In addition, the properties of complex 1, such as the elemental analysis, FT-IR spectroscopy, X-ray powder diffraction, and fluorescence spectroscopy were also characterized and are discussed in detailed.

In this report, seven new luminescent metal–organic frameworks (LMOFs), [Zn(L)0.5(H2O)2]·H2O (1), [Zn(L)0.5(DMF)] (2), [Zn3(L)(μ3-OH)2(H2O)4] (3), [Zn2(L)(DMA)(H2O)]·5(H2O) (4), [Cd(L)]·2(H3O)·(H2O) (5), [Cd2(L)(H2O)3] (6), and [Pb(L)0.5(H2O)] (7) (H4L = [1,1′:4′,1′′-terphenyl]-2′,3,3′′,5′-tetracarboxylic acid; DMF = N,N-dimethylformamide; DMA = N,N-dimethylacetamide) have been solvothermally synthesized by using Zn(II), Cd(II), Pb(II) ions and H4L in different solvent systems, all of which have been routinely characterized by elemental analysis, FT-IR spectroscopy, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Single-crystal X-ray diffraction analyses show the different dimensionalities (1D, 2D or 3D) of complexes 1–7. Comparative structural studies of 1–7 reveal that the L4− ligands adopt different coordination morphologies: 1 (η1μ1χ1), 2 (η2μ2χ2), 3 (η2μ2χ2), 4 (η2μ2χ2; η1μ1χ1), 5 (η2μ1χ2), 6 (η2μ2χ2; η2μ2χ3), and 7 (η2μ2χ2; η2μ3χ4) with Zn(II) (74 pm), Cd(II) (97 pm) and Pb(II) (119 pm) in different solvent systems, which produce the complexes with different frameworks. Complex 1 displays a 1D dimeric chain. Complexes 2 and 5 present a 2D layer structure with a uninodal 4-connected sql net with a symbol of (44·62). Complexes 3, 6 and 7 have a 3D dense packing structure based on infinite 1D rod-like secondary building units (SBUs). Complex 3 is designated as a binodal (4, 6)-connected fry topological net with the point symbol (510·63·78)(54·62). The whole network of 6 can be simplified as a binodal (4, 8)-connected flu topological net with a point symbol of (412·612·84)(46)2. Complex 7 can be seen as a new binodal (5, 10)-connected topological net with the point symbol (410)2(428·616·8). Complex 4 shows a 3D framework based on a binuclear [Zn2(CO)3O3] SBU, which can be viewed as a uninodal 4-connected sra topological net with the point symbol (42·63·8). Further, the solid-state luminescence properties of the complexes were measured and studied intensively at room temperature.

Four new complexes, namely {[Cd(L1)2]·(H2O)·(DMA)}n (1), {[Zn(L1)2(HL1)]·3.5H2O}n (2), {[Pb(L2)(HCOO)]·0.5H2O·0.5DMF}n (3), and {[Zn(L2)(NO3)(H2O)]·0.5H2O·0.5CH3CN}n (4), were synthesized by two isomeric (2-(pyridin-4-yl)-benzimidazole-5-carboxylic acid) (HL1) and (2-(pyridin-2-yl)-benzimidazole-5-carboxylic acid) (HL2) under hydro(solvo) thermal conditions. The ligands in the complexes adopt different coordination modes to connect the metal centers and finally form three-dimensional structures with different pore size. The results of fluorescence tests show that complex 3 has high sensitivity and selectivity to both Fe3+and MnO4−, the quenching constants are 8.74 ​× ​104 ​L ​mol−1 and 3.88 ​× ​104 ​L ​mol−1, and the minimum detection limit are 1.17 ​× ​10−5 ​mol ​L−1 and 4.48 ​× ​10−5 ​mol ​L−1, respectively. In addition, complex 1 has fast and efficient adsorption capacity for Congo red (CR) and Methyl green (MG).

The self-assembly of Zn2+ ion and an azolyl-carboxyl bifunctional ligand, 4,6-bis(triazol-1-yl)isophthalic acid (H2btzip), give rise to one three-dimensional (3D) porous metal-organic framework (MOF), [Zn(btzip)(H2O)0.5]·H2O (1). The MOF shows a rare (4,8)-connected scu net containing 1D channels, based on 4-connecetd ligands and 8-connected [Zn(COO)2(H2O)] dimers. Owing to the decoration of uncoordinated N atoms in porous walls, 1 can selectively capture CO2 molecules over CH4 with high adsorption heat and considerable selectivity. The different adsorption sites for CO2 in 1 were deeply explored by simulations. In addition, 1 also displays strong solid-state luminescence that is from the intraligand charge transfer.

Two new Co(II) metal-organic frameworks, namely [Co{sub 2}(bpm)(H{sub 2}O){sub 3}(L)]{sub n} (1) and ([Co(bpe)(H{sub 2}O)(H{sub 2}L)]·(bpe){sub 0.5}·(H{sub 2}O)){sub n} (2), (H{sub 4}L=1,1′:2′,1″-terphenyl-3,3″,4′,5′-tetracarboxylic acid, bpm=bis(4-pyridyl)amine, bpe=1,2-bis(4-pyridyl)ethene), have been obtained under hydrothermal conditions. Both complexes 1 and 2 have been characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complexes 1 and 2 consist of 1D Co(II) chains bridging by carboxylate groups in syn-anti fashion. 1 shows a novel 3D tri-nodal (4,6,10)-connected net with a (3.4{sup 3}.5{sup 2}){sub 2}(3{sup 2}.4{sup 14}.5{sup 12}.6{sup 12}.7{sup 4}.8)(3{sup 2}.4{sup 2}.5{sup 5}.6{sup 4}.7{sup 2}) topology. While 2 exhibits a 2D sql layer. Magnetic susceptibility measurements indicate that both 1 and 2 show weak antiferromagnetic interactions between the adjacent Co(II) ions in 300–8 K for 1 and 300–16 K for 2, respectively, and then 2 also displays ferromagnetic coupling at lower temperatures. - Graphical abstract: Two Co(II) coordination polymers with similar metal chain bridging by carboxylates in syn-anti fashion have been synthesized. Both 1 and 2 show weak antiferromagnetic interactions in high temperature, and then 2 also displays ferromagnetic coupling at lower temperatures. - Highlights: • Two Co(II) coordination polymers with similar metal chain bridging by carboxylates. • A novelmore » 3D (4,6,10)-connected net and a 2D sql layers. • A antiferromagnetic coupling at high temperature for 1 and 2. • A ferromagnetic coupling at lower temperature for 2.« less

Caged supramolecular systems are promising hosts for guest inclusion, separation, and stabilization. Well-studied examples are mainly metal-coordination-based or covalent architectures. An anion-coordination-based cage that is capable of encapsulating halocarbon guests is reported for the first time. This A4L4-type (A=anion) tetrahedral cage, [(PO4)4L4](12-), assembled from a C3-symmetric tris(bisurea) ligand (L) and phosphate ion (PO4(3-)), readily accommodates a series of quasi-tetrahedral halocarbons, such as the Freon components CFCl3, CF2Cl2, CHFCl2, and C(CH3)F3, and chlorocarbons CH2Cl2, CHCl3, CCl4, C(CH3)Cl3, C(CH3)2Cl2, and C(CH3)3Cl. The guest encapsulation in the solid state is confirmed by crystal structures, while the host-guest interactions in solution were demonstrated by NMR techniques.

Three coordination networks with the 1, 2,4-triazole linking units 3-(4′-imidazole phenyl)-5-(pyrid-2′′-yl)-1, 2,4-triazole (HIppyt) and 3-(pyrazin-2′-yl)-5-(4′-(pyrid-4′′-yl)-phenyl)-1, 2,4-triazole (Hpypypt), respectively, were synthesized and structurally characterized. The structures of [Mn(Ippyt)2·2H2O] (1) and [Zn(Ippyt)2·2H2O] (2) were found to be similar despite the presence of different metal ions. When Ippyt was replaced by pypypt to react with Zn(OAc)2·2H2O, the 2D coordination polymer, {[Zn(pypypt)2]·2DMF}n (3) formed. The adjacent zinc(II) atoms with similar octahedral coordination environment are interlinked by four separate pypypt ligands to construct a 2D network structure. The biological activities of 1 and 3 were studied. The results indicate that 1 and 3 exhibit certain antimicrobial activities. Furthermore, solid-state properties of thermal stability and photoluminescence properties at room temperature for these crystalline materials were also investigated.

Five new solvent-induced cadmium coordination architectures, {[Cd(bib)(5-Br-H2ip)]·EtOH}n (1), {[Cd0.5(bib)0.5(5-Br-H2ip)0.5]·3H2O}n (2), {[Cd2(bib)(5-Br-H2ip)2(MeOH)]}n (3), {[Cd(bib)0.5(5-Br-H2ip)(H2O)2]·H2O}n (4), and {[Cd(bib)0.5(5-Br-H2ip)(H2O)]}n (5), have been constructed from the same materials (1,4-bis(2-methyl-imidazol-1-yl)butane (bib), 5-bromoisophthalic acid (5-Br-H2ip) and Cd(Ac)2·2H2O) under different reaction solvents. As controlled by solvent systems, compound 1 shows a 3-fold interpenetrating 3D framework based on the left- and right-handed helical chains, while compound 2 reveals a 3-fold interpenetrating 3D network and each single net is based on the left-handed, right-handed and meso-helical chains. Compound 3 is a 3D framework that can be simplified as a 6-connected net with (48·62) topology. Both 4 and 5 display 3D supramolecular frameworks through weak aromatic π–π stacking interactions and hydrogen bonding interactions. However, the topologies of 4 and 5 are definitely different. Compound 4 presents a 3-connected net with (82·10) topology, while compound 5 reveals a 4-connected net with (42·63·8) topology. The effects of solvents on the crystal structures were discussed and thermogravimetric analysis and solid-state photoluminescence results for 1–5 were investigated.

Two new copper coordination complexes, [Cu(PI)(OX)(H2O)]·H2O (1) and [Cu(PI)(fum)(H2O)]·H2O (2) [PI = 2-(2′-pyridyl) imidazoline, OX2− = dianion of oxalic acid and fum2− = dianion of fumaric acid], were synthesized by interface diffusion method based on Cu(II) ions, PI ligands and aliphatic dicarboxylic acids. Complex 1 is a mononuclear complex which spreads into a 3D (4,9)-connected supramolecular network via hydrogen bond interactions, while complex 2 features a 1D zigzag chain with two different orientations. These two compounds are characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, infrared spectra, and thermogravimetric analyses.

Three new coordination polymers, [Ag4(H2bpz)4(SO4)2]·H2O (1), [Ag2(H2bpz)2(SO4)]·3H2O (2), and [Ag3(H2bpz)4](SO4)2/3(OH)5/3·4H2O (3) have been solvothermally synthesized with Ag2SO4 and flexible ligand 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2bpz) in different solvents and temperatures. Complex 1 is a 2-fold interpenetrated three-dimensional (3D) framework with an uncommon (3,5)-connected hms topology. Complex 2 is a structural isomer of 1 and shows a three-connected 2D ths net consisting of interesting 3-fold and 2-fold heterochiral helical chains. Complex 3 discloses a grid layer structure, containing heterochiral helical chains and an unusual meso-helix. More interestingly, three sets of layers in 3 stack in different directions, affording an unprecedented 2D + 2D + 2D → 3D polycatenating cationic framework with 1D + 3D porous systems. In 1-3, H2bpz exhibit exobidentate bridging fashions with wide-ranged interpyrazole tilting angles and changeable coordination configurations, such as cis and trans fashions in 1 and 3 and uniform trans fashion in 2. These lead to the isomeric [Ag(H2bpz)]n arrays of wavelike and helical chains in 1 and 2, respectively. Complexes 1-3 display solid-state photoluminescence stemming from the ligand-centered fluorescent emissions of H2bpz. Because of the highly polar framework, 3 shows excellent adsorption selectivity for CO2 over N2.

Five novel transition metal (Zn, Cd, Mn and Co)-based coordination polymers 1 – 5 with a flexible rodlike N,N′-donor ligand (bbi = 1,1′-(1,4-butanediyl)bis(imidazole))and four O-donor polycarboxylate anions (H 2 oxa = oxalic acid; H 2 fma = fumaric acid; H 2 bpdc = 2,2′-biphenyldicarboxylic acid; H 4 cit = citric acid) have been successfully synthesized and characterized by elemental analysis, IR spectra, and X-ray diffraction, namely {[Zn(bbi) 3 (NO 3 )]Br·2H 2 O} n ( 1 ), [Zn(oxa)(bbi)] n ( 2 ), [Mn(fma) 2 (bbi) 2 (H 2 O) 2 ] n ( 3 ), [Cd 2 (bpdc) 2 (bbi) 2 ] n ( 4 ) and {[Co 8 (cit) 4 (bbi) 6 (H 2 O) 10 ]·7H 2 O} n ( 5 ). Compounds 1 – 5 display various coordination motifs due to different conformations of the bbi ligand, at the same time, owing to diverse coordination modes of the polycarboxylate ligands. And the effect of the polycarboxylate ligands plays important roles in the construction of extended networks. Compounds 1 , 2 and 5 all exhibit 2D layer structures, in which 1 displays a 3-fold interpenetration framework containing 2D networks with (6, 3) topology and 2 is a 2D structure with (4,4) topology. Compound 5 contains a 2D 4 4 grid-like layer with (4 4 ·6 2 ) topology composed of octanuclear cobalt clusters. Two high-dimensional compounds (3D) with a microporous network, containing 1D flower-like metal–organic motifs interlinked by bbi ligands for 4 and a 3-fold interpenetrating network with 6 6 -dia topology by considering the manganese ion as a four-connected node for 3 , are observed. The biological activities of the title compounds have been studied. The results indicate that 1 – 5 exhibit certain selective antimicrobial activities against Escherichia coli , Staphylococcus aureus and Enterobacter aerogenes , besides, 5 exhibits more obvious radical-scavenging activities than that of bbi ligand. Furthermore, Solid-state properties of thermal stability and the photoluminescence properties at room temperature for these crystalline materials have also been investigated.

In this paper, we have demonstrated a simple surfactant-free solution method for the synthesis of sea urchin-like nickel carbonate hydroxide, which was characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermal gravimetric analysis, nitrogen adsorption–desorption isotherms, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Two types of carbonate species, a surface unidentate carbonate-like species and a crystal lattice carbonate species, were proposed based on the FTIR and symmetry analysis. The toxic ion-exchange properties towards As(V), Cd(II), and Cu(II) ions were investigated. At pH 5.0, the exchange capacities of Cd(II) and Cu(II) ions were 120.5 and 109.3 mg g−1, respectively, through the ion-exchange between nickel ions with them, which was confirmed by XPS. For As(V) ion removal, the maximum exchange capacity was 49.6 mg g−1 without any pH adjustment, which should be of importance for water treatment. Furthermore, a novel ion-exchange mechanism between the surface unidentate carbonate-like species and As(V) ions was proposed, which was revealed by XPS and FTIR.

When the coordination sites of ligands were shifted, the solvothermal reactions of four positional isomeric asymmetrical pyridyldicarboxylatic acids with Cd(NO3)2 generated four new coordination polymers, [Cd(L1)(DMF)3]·DMF·H2O (1), [H2N(CH3)2]2[Cd(L2)2]·3DMF·H2O (2), [Cd(L3)(H2O)2] (3), and [Cd(L4)]·1.5DMF (4), where DMF = N,N-dimethylformamide, H2L1 = 2-(3'-carboxylphenyl)isonicotinic acid, H2L2 = 2-(4'-carboxylphenyl)isonicotinic acid, H2L3 = 5-(3'-carboxylphenyl)nicotic acid, and H2L4 = 2-(3'-pyridyl)terephthalic acid. 1 shows a rare 2D fabric structure. 2 discloses a grid-layer structure with heterochiral helical chains and in which three sets of layers stack in different directions, affording an unprecedented 2D + 2D + 2D → 3D polycatenating framework with 3D intersecting porous systems. 3 also displays a 2D layer possessing strong intralayer π···π interactions and interlayer hydrogen bonds. 4 contains a rare Cd2(COO)4 paddle-wheel unit and forms a 3D framework with 1D open channels. The carboxyl and pyridyl groups of the positional isomeric H2L1-H2L4 ligands show distinct bridging fashions, which leads to the production of versatile architectures of 1-4, and their effects on the crystal structures are discussed. 1-4 reveal solid-state photoluminescence stemming from intraligand charge transfer. 2 and 4 show high selectivity for CO2 over CH4 but with different CO2 adsorption enthalpies. Grand canonical Monte Carlo simulations identified the multiple adsorption sites in 2 for CO2.

A V-shaped ligand bis(N-methylbenzimidazol-2-ylmethyl)benzylamine (L) and its zinc(II) complex, [ZnL 2](pic)2 · 2CH3CN (pic = picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray crystallographic analysis revealed that the Zn(II) complex possesses a distorted trigonal bipyramidal geometry. Supramolecular interactions arising from various intra- or intermolecular π···π stacking interactions contributed to the form of the multidimensional configuration. Interactions of L and Zn(II) complex with DNA were monitored using spectrophotometric methods and viscosity measurements. The results suggest that L and Zn(II) complex both bind to DNA via intercalation and Zn(II) complex binds to DNA more strongly than L. Moreover, the Zn(II) complex also exhibited potential antioxidant properties in vitro.

The first transition–metal coordination polymer {[Cd2L2(H2O)2]·2H2O}n (1) based on a new 1,2,4-triazole derivatives H2L (H2L = 3-(pyrid-2-yl)-5-(1 H-1,2,4-triazol-3-yl)-1,2,4-triazole) is presented, which not only exhibits an example assembled from 1D [Cd1L] chains to 3D (3,4)-connected network linked through [Cd2(trz)]2 dimeric units, but also shows high thermal stability and strong photoluminescence at room temperature.

A new coordination polymer, {[Ag(H3bptc)(bpe)] · 2H2O} n (1) (H4bptc = 3,3′,4,4′-benzophenonetetracarboxylic acid, bpe = 1,2-bis(4-pyridyl)ethene), has been synthesized through a hydrothermal technique and structurally characterized. The crystal structure of 1 exhibits a 2-D hydrogen-bonding sheet between H3bptc− and two free water molecules. Fluorescent property, TG analysis, and X-ray powder diffraction for 1 were also measured and discussed.

A new two-dimensional Cu(I)-framework [Cu3(deppz)(mtta)I] (1) [(Hdeppz = 3,5-diethyl-4-(4-pyridyl)-pyrazole, Hmtta = 5-methyltetrazole] has been solvothermally synthesized and structurally characterized. The framework contains an unprecedented cyclic Cu4(μ-pz)2(μ-mtta)2 cluster (Cu4) with twelve-membered coplanar Cu4N8 metallocycle, which contains coordinatively unsaturated Cu(I) centers and acts as a soft π-acid motif to contact with iodine atoms from Cu2I2 dimer of adjacent layers, generating a 3D supramolecular framework. The framework exhibits high thermostability and bright green-blue solid-state luminescence.

Three Zn II /Cd II -coordination polymers based on 2-propyl-4,5-imidazoledicarboxylate (H 3 pimdc), namely, [Zn(Hpimdc)H 2 O] n ( 1 ), [Cd(H 2 pimdc) 2 ] n ( 2 ) and [Cd 2 (Hpimdc) 2 (bbi) 0.5 (H 2 O) 2 ] n [bbi = 1,10-(1,4-butanediyl)bis(imidazole)] ( 3 ), have hydrothermally been synthesized, which exhibit a systematic dimensional variation by changing the metal ions or introducing the auxiliary ligand. Complex 1 is a 1D zig-zag polymeric chain, which is finally extended into a 3D supramolecular network through R 4 4 (12) O–H⋯O H-bonding rings. Complex 2 shows a 2D layer comprised alternately arranged left- and right-handed helical chains. Complex 3 features a rare (3,3)-connected 8 3 network with opposite chiral layers in a slipped ABAB fashion. The photoluminescent properties and thermal stabilities of three complexes are also discussed.

Two new coordination polymers, [Zn(PyHBIm)2(IPA)]•3H2O (1), [Cd(PyHBIm)(IPA)(H2O)2]•2H2O (2), were synthesized under hydrothermal conditions based on 2-(3-pyridyl)benzimidazole (3-PyHBIm) and isophthalic acid (IPA). The complexes were characterized by single crystal X-ray diffraction. They contain simple 1D chains and can be assembled into a 3D network through aromatic π–π stacking interactions and hydrogen bonding interactions. Their luminescent properties were studied in the solid state at room temperature.

A new metal-organic framework, {[Co1.5(μ2-OH)(L)(bipy)0.5] ·0.5DMF}n (1) (H2L = (4,4′-(hexafluoroisopropylidene)bis(benzoic acid) and bipy = 4,4′-bipyridine), has been prepared under solvothermal conditions using flexible dicarboxylate and rigid N-donor co-ligands in the presence of Co(II) ion as the building blocks. The x-ray single-crystal diffraction analysis indicates that 1 possesses a three-dimensional (3D) layer–pillar structure with one-dimensional (1D) metal-carboxylate chain. The Co(II) ions are bridged by L2− to generate a two-dimensional (2D) sheet, which is further pillared by bipy into a 3D framework with {44.62}{45.65}2 topology. In addition, the variable-temperature magnetic susceptibility measurement indicates there exists an anti-ferromagnetic behavior between in the Co(II) ions of 1.

Six new coordination polymers, namely, [Zn(3-PyHBIm)(oba)H2O] (1), [Cd(3-PyHBIm)(oba)H2O] (2), [Ni(3-PyHBIm)(oba)H2O]·3H2O (3), [Zn(4-PyHBIm)(oba)] (4), [Cd(4-PyHBIm)2(oba)]·H2O(5), and [Co(4-PyHBIm)2(oba)]·H2O (6) were synthesized under hydrothermal conditions based on 2-(n-pyridyl)benzimidazole (n-PyHBIm) and 4,4′-oxybis-(benzoate) (oba) ligands. The compounds were characterized by single crystal X-ray diffraction, IR, and thermogravimetric and elemental analyses. Compounds 1 and 2 contain simple one-dimensional (1D) polymeric chains assembled into a three-dimensional (3D) network through aromatic π–π stacking interactions and hydrogen bonding interactions. Compound 3 contains 1D polymeric chains with side arms which assembled into a two-dimensional (2D) network with channels and further assembled into a 3D network though C–H···π interactions. Compounds 4 and 5 form 1D molecular ladder coordination polymers. Compound 6 consists of 2D coordination networks with 2-fold interpenetration. The luminescence p...

Five novel Zn(II)/Cd(II)-based coordination polymers 1–5 with a flexible disulfide derivative of the nicotinate 6,6′-dithiodinicotinic acid (H2cpds) and two rodlike N,N′-donor ligands (bpa =1,2-bi(4-pyridyl)ethane; bpp = 1,3-bis(4-pyridyl)propane) have been successfully synthesized under the liquid diffusion condition and characterized by elemental analysis, IR spectra, and X-ray diffraction, namely {[Zn(cpds)]·H2O}n (1), {[Zn(cpds)(bpa)0.5]}n (2), {[Zn(cpds)(bpp)]}n (3), {[Cd(cpds)(bpa)1.5]·H2O}n (4), and {[Cd2(cpds)2(bpp)·(H2O)3]·4H2O}n (5). Complexes 1–5 display various coordination motifs due to different conformations, and coordination modes of the H2cpds ligand, at the same time the effect of the auxiliary ligands plays important roles in the construction of extended supramolecular networks. Complexes 2–4 all exhibit 2D layer structures, in which 2 displays a 2-fold 2D → 2D parallel interpenetration framework containing a rotaxane-like motif and 3 is a 2D 44 gridlike layer. Compound 4 contains two k...

A series of mixed-ligand complexes of tris(acetylacetonato) iridium(III) with N-heterocyclic ligands, namely [bis(acac-O,O′)(acac-C3)Ir(L)], where acac = acetyacetonato; L = 2-picoline (1), 3-picoline (2), 4-picoline (3), have been synthesized via the reaction of [bis(acac-O,O′) (acac-C3)Ir(H2O)] with the corresponding ligand, respectively. Molecular structures of all complexes were determined by using single-crystal X-ray diffraction. The results reveal that these complexes have slightly distorted octahedral coordination geometries.

Three new coordination polymers, namely, {[Cd 3 (L 1 ) 2 (IP) 2 (H 2 O) 4 ]} n ( 1 ), {[Cd 2 (L 2 ) 2 (IP) 2 ]·(CH 3 OH)(DMF)} n ( 2 ) and [Cd(L 3 )(IP)] n ( 3 ) (H 3 L 1 = benzene-1,2,4-tricarboxylic acid, H 2 L 2 = 2,2-bis(4-carboxyphenyl)hexafluoropropane, H 2 L 3 = 1,3-phenylenediacetic acid and IP = 1H-imidazo[4,5-f][1,10]-phenanthroline), were prepared via self-assembly of pharmaceutical agent IP with cadmium sulfate in the presence of the different backbones of carboxylate linkers under mild conditions. All the polymers possess 2D structural motifs. The rigid tricarboxylate ligand links the metal centers to form a tetranuclear core in 1 . In 2 , the 2D network with trinuclear cores is further extended into 3D supramolecular arrays through aromatic stacking interactions. Interestingly, IP ligand acts in a tridentate mode via the two N atoms of pyridyl rings and the third N atom of imidazole ring and connects metal atoms into 1D zigzag chain in 3 . The structural analysis reveals that the backbones of carboxylates have critical effect on the construction of the complexes. Solid-state luminescent spectra of the Cd(II) complexes indicate intense fluorescent emissions.

A N,N′-bisferrocenesulfonyl bisbenzimidazole compound 1,4-bis(1-ferrocenesulfonyl-2-benzimidazolyl) butane was prepared. Its crystal structure was determined. The crystal belongs to triclinic with space group P-1 and a=0.87241(13) nm, b=0.97553(15) nm, c=1.4120(2) nm, and α=83.041(2) °, β=72.454(2)°, γ=69.732(2)°, the unit cell volume V=1.0746(3) nm3, the molecule number in one unit cell Z=1, the absorption coefficient μ=1.191 mm−1, the calculated density Dc=1.584 g/cm3. The theoretical investigation of the compound as a structure unit was fully optimized by B3LYP/6-31G method in Gaussian 03 package, and the most stable structure of the compound in theory was obtained. The two results were compared. The optimized structure was in accordance with the crystal structure in the main, suggesting that the molecular geometry optimization of the structures was reliable and the calculation method used was reliable. The distribution of atomic charges and the energy, and composition of frontier molecular orbits were analyzed. Thermal analysis indicated that it is stable before melting.

Self-assembly of rigid dicarboxylate and flexible N-donor co-ligands in the presence of divalent metal ion affords a new polymer of [Cu(bpea)(bib)]n (1) (bpea = biphenyle-thene-4,4′-dicarboxylate and bib = 1,4-bis(2-methyl-imidazol-1-yl)butane). The structure of 1 exhibits an unusual 2D → 3D motif with sql topology. An interesting 3D polycatenane metal-organic framework was obtained from the assembly of mixed rigid and flexible in the presence of transition metal. The structure reported herein demonstrates that backbone of organic acid play the central role of a structure-directing unit

The conformational bis-triazole ligand 4,4'-bis[(1,2,4-triazol-1-yl)methyl]biphenyl (btmb, 1), was successfully synthesized, and seven new coordination polymers, namely {M(oba)-(btmb)} n [M = Cd 2+ (2), Co 2+ (3), Ni 2+ (4), and Zn 2+ (5)], {M(sdba)(btmb)} n [M = Co 2+ (6) and Cd 2+ (7)], and {[Cu(H 2 odpa)(btmb)(H2O)]·2H20} n (8), (H 2 oba = 4,4'-oxydibenzoic acid, H 2 sdba = 4,4'-sulfonyldibenzoic acid, and H 4 odpa = 4,4'-oxydiphthalic acid), have been synthesized by utilizing the btmb ligand and the polymers have been characterized in detail. Complexes 2-4 are isostructural exhibiting 2D-layer structures and can be described as (3,4)-connected networks with (4 2 .6 3 .8)(4 2 .6) topological notation. Complex 5 shows 2D layers with left- and right-handed helical chains and has a (3,4)-connected net with (4.5 2 )(4.5 3 .7 2 ) topology. Complexes 6 and 7 are isostructural and display 2D undulating networks with (4,4) sheets that are further packed through van der Waals interactions to generate a 3D supramolecular structure. Complex 8 also represents a 2D network with a 4 4 -sql net, which is extended into a 3D supramolecular framework by hydrogen-bonding interactions. The structural differences of these complexes demonstrate that the conformation of the btmb ligand and flexible aromatic polycarboxylate anions play critical roles in the formation of the resulting frameworks. Furthermore, their thermal properties have been studied by thermogravimetric analysis (TGA) and the TGA results reveal that the triazole-based frameworks have a high thermal stability, which suggests they are good candidates for the construction of more stable complexes. The photoluminescent properties of complexes 2, 5, and 7 have also been studied.

Three coordination polymers containing 2-(2-pyridyl)benzimidazole (PyHBIm) ligand, namely {[Zn3(PyBIm)3(PyHBIm)2(tma)(H2O)]•H2O}n (1), [Zn(PyHBIm)(oba)]n (2), [Cd(PyHBIm)(oba)]n (3), (tma = trimesate, oba = 4,4′-oxybis-(benzoate)), have been prepared through hydrothermal reaction. Compound 1 exhibits one-dimensional (1D) helical structure. However, compounds 2 and 3 display 1D meso-helical structure. These 1D structures are further assembled into three-dimensional (3D) networks through aromatic π–π stacking interactions and hydrogen bonding interactions. Moreover they all exhibit strong photoluminescence at room temperature and may be good candidates for potential luminescence materials.

A fascinating 3D entangled metal-organic framework, namely, {[Co(2)(bcp)(2)]·3H(2)O}(n) (1), was obtained through the solvothermal generation of flexible and long dicarboxylate (bcp) and metal salt. The crystal structure contains a 1D metal chain with bcp ligands wrapped around it in a wavy line and features an unusual entangled topological net. Furthermore, the magnetic behavior of 1 was also studied and indicated the existence of ferromagnetic interaction and long-range ordering character.