Tetravalent silicon connectors MenSi(p-C6H4CO2H)(4-n) (n = 0, 1, 2) for the construction of metal-organic frameworks

A series of silicon-centered connecting units, Me(n)Si(p-C6H4CO2H)(4-n) (n = 0, 1, 2), have been prepared and their coordination polymers with Zn(II) metal atoms studied. The tetra-acid L1 (n = 0) acts as a tetrahedral node and reacts with Zn(II) centers to give 1, a novel interpenetrating 3D network containing distorted tetrahedral bimetallic secondary building units (SBUs). The triacid L2 (n = 1) acts as a trigonal pyramidal node and forms an intercalated 2D layered network, 2, with Zn(II) ions, containing distorted octahedral tetranuclear SBUs. Last, the bent diacid L3 (n = 2) reacts with Zn(II) centers to give 3, a corrugated 2D layered structure containing 1D zinc hydroxo chains. Together these three new coordination polymers demonstrate the potential versatility of tetravalent silicon containing connecting ligands for metal-organic framework construction.     

Unprecedented (3,10)-connected 2-D metal-organic framework constructed from octanuclear cobalt(II) clusters and a new bifunctional ligand

A metal-organic framework with the highest connectivity of 2-D topology was first assembled from an octacobalt(II) cluster as a 10-connected node and a new bifunctional ligand 1-(3,5-dicarboxy-phenyl)-4-phenyl-1H-1,2,3-triazole as a 3-connected node as well as "double bridge" linkers.     

基于柔性四羧酸及4,4'-联吡啶的sqc422型钴(Ⅱ)配位聚合物

采用水热法合成了一种基于1,3-二[3,5-(二羧基)苯氧基]-2-羟基丙烷(H4L)和4,4′-联吡啶(Bipy)的Co(Ⅱ)配合物:[Co2(L)(Bipy)2]n(1),并利用红外光谱(IR)、紫外-可见光谱(UV-Vis)、热重分析(TGA)、单晶X-射线衍射、粉末X射线衍射(XRD)及元素分析对其结构进行了表征。配合物1属单斜晶系,C2/c空间群。在配合物1中,由2个六配位钴原子组成的双核原子簇可简化为八面体型6-连接点,连接4个羧酸配体分子L和其他2个双核原子簇。羧酸配体L可简化为四面体型4-连接点,连接4个双核原子簇。平行排列的2个联吡啶分子连接两个相邻双核原子簇,相当于"双桥",简化为拓扑回路的边。因此,配合物1的骨架描述为sqc422拓扑网络。     

新型Cd(Ⅱ)-MOF的合成及对4-硝基苯胺的高效识别

采用新型1,3,5-三(1H-苯并[d]咪唑-2-基)苯(TBB)配体及2,5-二羟基对苯二甲酸(H₂dhtp)线性配体, 以Cd(Ⅱ)离子为中心节点, 构筑了具有新型拓扑结构(unj)的手性金属-有机框架材料[Cd(TBB)(dhtp) ](配合物1). 该配合物具有较强的光致发光性能, 可分散在溶液中荧光检测硝基配合物等污染物. 其中, 4-硝基苯胺对配合物1具有高效的荧光猝灭能力, 检测限可低至0.145 mg/L, 并具有较好的选择性.     

3D framework containing Cu4Br4 cubane as connecting node with strong ferroelectricity

The methanolothermal reaction of (S)-1,4-diallyl-2-methylpiperazine (DAMP) with an excess CuBr affords a novel homochiral 3D framework (DAMP)3(Cu4Br4)2(H2O)3 (1) in which Cu4Br4 cubane acts as a connecting node to mimic the pure inorganic role in the ferroelectricity to enhance the remnant polarization value which is comparable to that of BaTiO3 synthesized by peptide-assisted synthesis.     

Fused pyridazines: rigid multidentates for designing and fine-tuning the structure of hybrid organic/inorganic frameworks

Fused pyridazines (1,2,3,6,7,8-hexahydro-cinnolino[5,4,3-cde]cinnoline, L and its 2,2,7,7-tetramethyl derivative, Me4L) are designed as rigid multidentate ligands for the construction of framework solids. In combination with copper(I) bromide (iodide) they provide excellent structural examples for predictive engineering and the possibilities for further fine-tuning of the framework architectures facilitated by the tetradentate function of the ligands and effective cooperation of organic and inorganic bridges. This study features control over helical structures for (CuX)n chains and homo/heterochiral combination of the helices in the lattice, the design of a range of channelled and tubular CuX networks and the structural significance of ligand shape complementarity. 3D tetragonal Cu2X2(L) frameworks exist either as chiral or achiral supramolecular isomers Cu2I2(Me4L) and Cu12I12[Cu(CH3CN)]3(L)(6-)Cu3I6.CH3CN illustrate 3D hexagonal channelled and tubular arrays; Cu2I2(Me4L)(CH3CN) and Cu4I4(L)(CH3CN)2 complexes are 1D polymers.     

Inorganic-organic interpenetrating frameworks: 4,4'-bipyridine N,N'-dioxide as a bridging hydrogen-bond acceptor

4,4'-Bipyridine N,N'-dioxide (L) acts as a hydrogen-bond acceptor in the compounds ([M(NO3)2(H2O)4].L2) (M = Co, Ni) to form doubly-interpenetrated framework materials with sixfold topological connectivity.     

Syntheses, structures, and photoluminescence properties of metal(II) halide complexes with pyridine-containing flexible tripodal ligands

Seven coordination compounds, [Zn(L3)Cl2] . MeOH . H2O (1), [Mn(L3)2Cl2] . 0.5EtOH . 0.5H2O (2), [Cu3(L2)2Cl6] . 2DMF (3), [Cu3(L2)2Br6] . 4MeOH (4), [Hg2(L4)Cl4] (5), [Hg2(L4)Br4] (6), and [Hg3(L4)2I6] . H2O (7), were synthesized by the reactions of ligands 1,3,5-tris(3-pyridylmethoxyl)benzene (L3), 1,3,5-tris(2-pyridylmethoxyl)benzene (L2), and 1,3,5-tris(4-pyridylmethoxyl)benzene (L4) with the corresponding metal halides. All the structures were established by single-crystal X-ray diffraction analysis. In complexes 1 and 2, L3 acts as a bidentate ligand using two of three pyridyl arms to link two metal atoms to result in two different 1D chain structures. In complexes 3 and 4, each L2 serves as tridentate ligand and connects three Cu(II) atoms to form a 2D network structure. Complexes 5 and 6 have the same framework structure, and L4 acts as a three-connecting ligand to connect Hg(II) atoms to generate a 3D 4-fold interpenetrated framework, while the structure of complex 7 is an infinite 1D chain. The results indicate that the flexible ligands can adopt different conformations and thus can form complexes with varied structures. In addition, the coordination geometry of the metal atom and the species of the halide were found to have great impact on the structure of the complexes. The photoluminescence properties of the complexes were investigated, and the Zn(II), Mn(II) and Hg(II) complexes showed blue emissions in solid state at room temperature.     

Synthesis,Structure and Magnetic Property of a Cobalt(II) Metal‐Organic Framework

The three‐dimensional (3D) porous cobalt(II) metal‐organic framework (MOF), [Co₃(L)₂(DMA)₂(MeOH)₂ · 4(DMA) · 6(MeOH)]_n ( 1 ) [L = fully deprotonated 2,7‐bis(4‐benzoic acid)‐N‐(4‐benzoic acid) carbazole, DMA = N,N‐dimethylacetamide], was synthesized by hydrothermal reaction. Based on X‐ray single‐crystal diffraction, structural analysis indicates that complex 1 crystallizes in the monoclinic C2/c space group. Complex 1 possesses a 3,6‐connected three‐dimensional (3D) topological structure with a point symbol of {4² · 6}₂{4⁴ · 6² · 8⁷ · 10²} when a trinuclear Co^II cluster was regarded as 6‐connected node and the organic ligands could be regarded as 3‐connected linkers between the 6‐connected nodes. The framework structure exhibits a one‐dimension (1D) channel with an accessible void of 4223.0 ų, amounting to 42.8 % of the total unit‐cell volume (9862.0 ų). Moreover, the magnetic properties of complex 1 were studied.     

2D and 3D Cu(hfac)2 complexes with nitronyl nitroxide biradicals

Reactions between Cu(hfac)2 and nitronyl nitroxide biradicals 1,4-bis[4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyrazol-1-yl]butane (L4) and 1,8-bis[4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyrazol-1-yl]octane (L8) gave respectively a framework compound [Cu(hfac)2]2L4 and a layered polymer compound [Cu(hfac)2]2L8. The framework of [Cu(hfac)2]2L4 consists of 66-membered condensed metallocycles. Inside the framework, the structure has macrohelixes (pitch approximately 25 A) extending along the [001] crystallographic direction. All the helixes have the same direction of winding; the crystals, therefore, are optically active, the structure corresponding either to P-isomer (P4(1)2(1)2) or to M-isomer (P4(3)2(1)2). The long distances between the Cu atoms and the O atoms of the coordinated >N-O groups (Cu-O 2.351-2.467 A) are responsible for ferromagnetic exchange interactions in Cu2+-O-N< and >N-O-Cu2+-O-N< exchange clusters.     

Entanglement of individual coordination polymers having helicates as building intermediates

A series of Ag(I) coordination compounds, from one-dimensional chains to 3D porous frameworks, were achieved from N,N'-bis[1-(2-pyrazinyl)ethylidene]benzil dihydrazone, L, via self-assembly, using helicates as effective secondary building units. Compound 2 [(Ag(2.75)L)(NO(3))(2.75)] was comprised of two opposite-handed 3D frameworks formed by connecting the 4(1) helical chains into (10(3)-b) nets. The pairs of the racemic 3D frameworks were connected through additional silver(I) centers and entangled each other forming a racemic 3D net. Compound 3 [(Ag(13)L(8))(BF(4))(13)(H(2)O)(12)] was comprised of a 3D framework that was constructed from double-helical building intermediates Ag(2)L(2) with one-dimensional infinite chains being threaded into the large voids of a 3D framework to form a weave structure. The ladder-like chains in compound 4 [(Ag(3)L(2))(ClO(3))(3)(CH(3)OH)(2)(CH(3)CN)] were formed by the addition of excess NaClO(3) into the methanol solution containing AgNO(3) and the ligand L, and the zigzag chains in compound 5 [(Ag(2)L(2))(ClO(4))(2)(CH(3)CN)(2)] were constructed by the addition of excess NaClO(4) into an acetonitrile solution containing AgNO(3) and the ligand L.     

New family of silver(I) complexes based on hydroxyl and carboxyl groups decorated arenesulfonic acid: syntheses, structures, and luminescent properties

Self-assembly of silver(I) salts and three ortho-hydroxyl and carboxyl groups decorated arenesulfonic acids affords the formation of nine silver(I)-sulfonates, (NH(4))·[Ag(HL1)(NH(3))(H(2)O)] (1), {(NH(4))·[Ag(3)(HL1)(2)(NH(3))(H(2)O)]}(n) (2), [Ag(2)(HL1)(H(2)O)(2)](n) (3), [Ag(2)(HL2)(NH(3))(2)]·H(2)O (4), [Ag(H(2)L2)(H(2)O)](n) (5), [Ag(2)(HL2)](n) (6), [Ag(3)(L3)(NH(3))(3)](n) (7), [Ag(2)(HL3)](n) (8), and [Ag(6)(L3)(2)(H(2)O)(3)](n) (9) (H(3)L1 = 2-hydroxyl-3-carboxyl-5-bromobenzenesulfonic acid, H(3)L2 = 2-hydroxyl-4-carboxylbenzenesulfonic acid, H(3)L3 = 2-hydroxyl-5-carboxylbenzenesulfonic acid), which are characterized by elemental analysis, IR, TGA, PL, and single-crystal X-ray diffraction. Complex 1 is 3-D supramolecular network extended by [Ag(HL1)(NH(3))(H(2)O)](-) anions and NH(4)(+) cations. Complex 2 exhibits 3-D host-guest framework which encapsulates ammonium cations as guests. Complex 3 presents 2-D layer structure constructed from 1-D tape of sulfonate-bridged Ag1 dimers linked by [(Ag2)(2)(COO)(2)] binuclear units. Complex 4 exhibits 3-D hydrogen-bonding host-guest network which encapsulates water molecules as guests. Complex 5 shows 3-D hybrid framework constructed from organic linker bridged 1-D Ag-O-S chains while complex 6 is 3-D pillared layered framework with the inorganic substructure constructing from the Ag2 polyhedral chains interlinked by Ag1 dimers and sulfonate tetrahedra. The hybrid 3-D framework of complex 7 is formed by L3(-) trianions bridging short trisilver(I) sticks and silver(I) chains. Complex 8 also presents 3-D pillared layered framework, and the inorganic layer substructure is formed by the sulfonate tetrahedrons bridging [(Ag1O(4))(2)(Ag2O(5))(2)](∞) motifs. Complex 9 represents the first silver-based metal-polyhedral framework containing four kinds of coordination spheres with low coordination numbers. The structural diversities and evolutions can be attributed to the synthetic methods, different ligands and coordination modes of the three functional groups, that is, sulfonate, hydroxyl and carboxyl groups. The luminescent properties of the nine complexes have also been investigated at room temperature, especially, complex 1 presents excellent blue luminescence and can sensitize Tb(III) ion to exhibit characteristic green emission.     

Coordination Assembly of Tetrahedral Ti4(embonate)6 Cages with Alkaline-Earth Metal Ions

Recently,the tetrahedral Ti₄L₆ cage(L=embonate)has been applied as the starting material to realize coordination assembly with transition and rare-earth ornoble metal ions through a two-step reaction.In this work,by employing the Ti₄L₆ cages to assemble with alkaline-earth metal ions(such as Mg²⁺,Ca²⁺and Ba²⁺)under different solvothermal conditions,a series of Ti₄L₆-based structures from simple cages to 1D chain,2D layer and 3D framework have been synthesized and structurally characterized.In addition,thermal stability,phase purity,UV-vis absorption spectrum,the fluorescent and third-order nonlinear-optical properties are also investigated.     

利用二次球形配位构筑疏水型隧道框架结构

质子化N,N,N',N'-四苄基乙二胺(L)可与[MCl4]2-(M=Mn, Co, Cu)形成二次球形配合物. 通过N—H…Cl相互作用构筑了1D带状和2D层状框架结构, 层中配体L的苄基通过C—H…Cl相互作用分别采取水平和垂直取向, 使1D带状和2D层状呈现凸凹交替排列. 通过层间凸凹部位的C—H…H—C相互作用, 形成了层间空穴, 进而构筑成了3D疏水型隧道框架结构, 乙醇分子能够填充于隧道之中. 在L·2H+·[CuBr4]2-晶体中, 由于[CuBr4]2-没有与配体L的苄基形成C—H…Br氢键, 使配体L的苄基采取了同向取向. 因而, 形成的2D层状框架结构是平展的, 未形成3D疏水型隧道框架结构, 也未发现与乙醇分子的包结现象.     

Solvent-induced single-crystal to single-crystal transformation of a 2D coordination network to a 3D metal-organic framework greatly enhances porosity and hydrogen uptake

Exposure to CH(2)Cl(2) at room temperature induces single-crystal to single-crystal transformation of the 2D coordination network [Zn(2)L(DMF)(4)]·2DMF·4H(2)O to the 3D metal-organic framework [Zn(2)L(H(2)O)(2)]·xsolv via dimerization of the metal-connecting points, leading to significant enhancement in framework stability, porosity, and H(2) uptake capacity.     

A multi-responsive luminescent sensor towards Fe_(3+) and acetone based on a Cd-containing metal–organic framework

A Cd-containing metal–organic framework(Cd L), formula as {[Cd_3(L)_2(H_2O)_6] 1.5DMF}, has been synthesized under solvothermal condition by the reaction of 4,40,400-(methylsilanetriyl)tribenzoic acid(H_3L) and Cd~(2+)ion. Single-crystal X-ray diffraction reveals that Cd L displays a three-dimensional framework with 2-fold interpenetration and DMF molecules locate in the void space of the channels. A topological analysis of the framework indicates Cd L is a 3,4-connected pto net. The photoluminescence properties of Cd L are systematically studied in detail. Impressively, Cd L shows excellent detection performance towards Fe~(3+)ion and acetone in the sensing experiments, which undoubtedly demonstrates the great potential of Cd Lasa highly selective multi-responsive luminescent sensor for the detection of organic solvents and metal ions.     

Novel eclipsed 2D cadmium(II) coordination polymers with open-channel structure constructed from terephthalate and 3-(2-pyridyl)pyrazole: crystal structures, emission properties, and inclusion of guest molecules

Five new eclipsed two-dimensional (2D) coordination polymers, [[Cd(2)(TPT)(2)L(2)](GM(1))(3/2)(H(2)O)](infinity) (1) (TPT = terephthalate, L = 3-(2-pyridyl)pyrazole, GM(1) = terephthalic acid), [[Cd(TPT)L](GM(2))(H(2)O)(2)]( infinity) (2) (GM(2) = L = 3-(2-pyridyl)pyrazole), [[Cd(TPT)L](GM(3))(1/2)(H(2)O)](infinity) (3) (GM(3) = mesitylene), [[Cd(4)(TPT)(4)L(4)](GM(4))(7/2)](infinity) (4) (GM(4) = tetramethylbenzene), and [[Cd(TPT)L](GM(5))(1/2)](infinity) (5) (GM(5) = naphthalene), have been synthesized and characterized by X-ray diffraction. All the five complexes take the similar eclipsed 2D open-channel framework with different guest molecules included in the cavities of their channels. TGA analysis indicates that the eclipsed open-channel frameworks are thermally stable up to 300 degrees C. The porous property of the 2D framework of 5 was also investigated by the XRPD technique, which indicated that the guest molecules included in the open-channel frameworks are removable and the framework is maintained after the removal of the guest molecules. Moreover, complexes 1-5 also display strong blue emission in the solid state.     

A lithium‐organic framework as a fluorescent sensor for detecting aluminum (III) ion

Due to the low coordination number and the relatively weak coordination ability, it is a great challenge to introduce Li⁺ into the construction of metal–organic frameworks (MOFs). Here, one Li‐based metal–organic framework (Li‐MOF), [Li₄L(DMF)₂]_n ( HNU‐31 ), is constructed by the assembly of LiNO₃ and 5‐(bis(4‐carboxybenzyl)amino)isophthalic acid (H₄L) ligand, which possesses a 3D framework, and can be serve as a luminescent sensor for detecting Al³⁺ ion with the detection limit of 4 × 10^?6 M.     

Novel Cd(II) coordination polymers with flexible disulfoxide ligands: effects of ligand spacers, terminal groups and counter anions on the complex framework formations

Five novel Cd(II) coordination polymers with three structurally related flexible disulfoxide ligands, [[Cd(L1)3](ClO4)2]n (1), [[Cd(L2)3](ClO4)2(CHCl3)]n (2), [Cd(L2)(NO3)2(H2O)]n (3), [Cd2(L3)2(NO3)4]n (4) and [[Cd(L3)3](ClO4)2]n (5), where L1= 1,3-bis(phenylsulfinyl)propane, L2= 1,4-bis(phenylsulfinyl)butane and L3= 1,4-bis(ethylsulfinyl)butane, were synthesized and structurally determined by X-ray diffraction. Complex 1 has a 2D layer structure, in which part of the L1 ligands bridge the Cd(II) ions to form double-bridging chains and the other part of ligands link such chains to form a 2D framework. Complexes 2 and 5 are isomorphous, showing unusual 2D (3,6) network structures containing triangular grids. Complex 3 adopts a 2D (4,4) network formed by L2 linking the NO3- bridged (Cd-O-N-O-)n 1D zigzag chains. By contrast, is a 1D chain, in which two Cd(II) centers are bridged by mu2-O of sulfoxide groups to form a dinuclear unit, and L3 ligands link such dinuclear units to form a 1D double-bridging chain. The structural differences among such complexes show that the ligand nature and counter anions have important influences on the complex structures, which may provide a rational method for controlling the framework formation in metal-organic coordination polymers.     

A fluorescent 3-D metal-organic framework with unusual tetranuclear zinc secondary building units

A 3-D metal-organic framework (MOF) {Zn₄(μ₃-OH)₂(bdc)₃(pad)₂}·2H₂O (1, H₂bdc = 1,4-benzenedicarboxylic acid, pad = 1,10-phenanthroline-5,6-dione) with unusual Zn₄(μ₃-OH)₂(COO)₆(N₂)₂ secondary building units (SBUs) has been hydrothermally synthesized and characterized by single crystal X-ray diffraction, powder X-ray diffraction, thermogravimetric analysis, elemental analysis, and infrared spectroscopy. The tetranuclear Zn₄ SBU was formed through two dinuclear Zn₂ clusters by sharing two μ₃-OH bridges. Considering this Zn₄ SBU as a six-connected node, the overall framework of 1 has a pcu topology. This tetranuclear Zn₄ SBU can be used as a node in construction of MOFs.