A one‐dimensional zinc(II) coordination polymer incorporating [1,1′‐biphenyl]‐4,4′‐dicarboxylate and N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands

In the title compound, catena‐poly[[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[1,1′‐biphenyl]‐4,4′‐dicarboxylato‐[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]], [Zn₂(C₁₄H₈O₄)Cl₂(C₂₆H₂₂N₄O₂)₃]_n, the Zn^II centre is four‐coordinate and approximately tetrahedral, bonding to one carboxylate O atom from a bidentate bridging dianionic [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand, to two pyridine N atoms from two N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands and to one chloride ligand. The pyridyl ligands exhibit bidentate bridging and monodentate terminal coordination modes. The bidentate bridging pyridyl ligand and the bridging [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand both lie on special positions, with inversion centres at the mid‐points of their central C—C bonds. These bridging groups link the Zn^II centres into a one‐dimensional tape structure that propagates along the crystallographic b direction. The tapes are interlinked into a two‐dimensional layer in the ab plane through N—H...O hydrogen bonds between the monodentate ligands. In addition, the thermal stability and solid‐state photoluminescence properties of the title compound are reported.     

Construction Of Two New 6‐connected Manganese(II) Metal Organic Frameworks via Isomeric Biphenyldicarboxylates Based on the Dinuclear Secondary Building Unit

Two coordination polymers, namely {[Mn(2,4′‐bpdc)(bimb)(H₂O)_0.5] · 0.5H₂O}_n ( 1 ) and [Mn(4,4′‐bpdc)(bimb)]_n · 2.5H₂O ( 2 ) [2,4′‐bpdc = biphenyl‐2,4′‐dicarboxylate, 4,4′‐bpdc = biphenyl‐4,4′‐dicarboxylate, and bimb = 1,4‐bis(1‐imidazol‐yl)‐2,5‐dimethyl benzene], were hydrothermally synthesized by reactions of manganese(II) salt with the rigid ligand 1,4‐bis(1‐imidazol‐yl)‐2,5‐dimethyl benzene and isomeric biphenyl dicarboxylate ligands. Complex 1 has an unusual 6‐connected three‐dimensional (3D) architecture with point symbol (4⁴.6¹¹). Complex 2 has also a 3D structure with two‐interpenetrated pcu topology with point symbol (4¹².6³). Structural comparisons show that the positions of the carboxylate groups in the ligand backbone play an important role in governing the structural topologies of these complexes.     

A three‐dimensional CdII coordination polymer constructed from 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylate and 1,4‐bis(1H‐imidazol‐1‐yl)benzene ligands

The title coordination polymer, poly[[aqua(μ₅‐1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]dicadmium(II)] dihydrate], {[Cd₂(C₁₆H₆O₈)(C₁₂H₁₀N₄)₂(H₂O)]·2H₂O}_n, was crystallized from a mixture of 1,1′‐biphenyl‐2,2′,5,5′‐tetracarboxylic acid (H₄bpta), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and cadmium nitrate in water–dimethylformamide. The crystal structure consists of two crystallographically independent Cd^II cations, with one of the Cd^II cations possessing a slightly distorted pentagonal bipyramidal geometry. The second Cd^II centre is coordinated by carboxylate O atoms and imidazole N atoms from two separate 1,4‐bib ligands, displaying a distorted octahedral CdN₂O₄ geometry. The completely deprotonated bpta⁴⁻ ligand, exhibiting a new coordination mode, bridges five Cd^II cations to form one‐dimensional chains viaμ₃‐η¹:η²:η¹:η² and μ₂‐η¹:η¹:η⁰:η⁰ modes, and these are further linked by 1,4‐bib ligands to form a three‐dimensional framework with a (4².6⁴)(4.6²)(4³.6⁵.7²) topology. The structure of the coordination polymer is reinforced by intermolecular hydrogen bonding between carboxylate O atoms, aqua ligands and crystallization water molecules. The solid‐state photoluminescence properties were investigated and the complex might be a candidate for a thermally stable and solvent‐resistant blue fluorescent material.     

New organic–inorganic frameworks incorporating iso‐ and heteropolymolybdate units and a 3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium multiple hydrogen‐bond donor

Poly[bis(3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium) γ‐octamolybdate(VI) dihydrate], {(C₁₀H₁₆N₄)₂[Mo₈O₂₆]·2H₂O}_n, (I), and bis(3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium) α‐dodecamolybdo(VI)silicate tetrahydrate, (C₁₀H₁₆N₄)₂[SiMo₁₂O₄₀]·4H₂O, (II), display intense hydrogen bonding between the cationic pyrazolium species and the metal oxide anions. In (I), the asymmetric unit contains half a centrosymmetric γ‐type [Mo₈O₂₆]⁴⁻ anion, which produces a one‐dimensional polymeric chain by corner‐sharing, one cation and one water molecule. Three‐centre bonding with 3,3′,5,5′‐tetramethyl‐4,4′‐bi‐1H‐pyrazole‐2,2′‐diium, denoted [H₂Me₄bpz]²⁺ [N...O = 2.770 (4)–3.146 (4) Å], generates two‐dimensional layers that are further linked by hydrogen bonds involving water molecules [O...O = 2.902 (4) and 3.010 (4) Å]. In (II), each of the four independent [H₂Me₄bpz]²⁺ cations lies across a twofold axis. They link layers of [SiMo₁₂O₄₀]⁴⁻ anions into a three‐dimensional framework, and the preferred sites for pyrazolium/anion hydrogen bonding are the terminal oxide atoms [N...O = 2.866 (6)–2.999 (6) Å], while anion/aqua interactions occur preferentially viaμ₂‐O sites [O...O = 2.910 (6)–3.151 (6) Å].     

A tubular one‐dimensional polymer constructed from alternating clusters of europium(III)–water and copper(I) chloride bridged by 4‐(pyridin‐4‐yl)benzoate

A new 3d–4f heterometallic polymer, poly[[aqua‐μ₃‐chlorido‐[μ₃‐4‐(pyridin‐4‐yl)benzoato]tris[μ₂‐4‐(pyridin‐4‐yl)benzoato]dicopper(I)erbium(III)] dihydrate], {[Cu₂Er(C₁₂H₈NO₂)₄Cl(H₂O)]·2H₂O}_n, was synthesized by the hydrothermal reaction of Er₂O₃, CuCl₂·2H₂O and 4‐(pyridin‐4‐yl)benzoic acid in the presence of HClO₄. The asymmetric unit contains one Er³⁺ cation, two Cu⁺ cations, one Cl⁻ anion, four deprotonated 4‐(pyridin‐4‐yl)benzoate ligands, one coordinated aqua ligand and two solvent water molecules. This tubular one‐dimensional polymer is constructed from alternating clusters of europium(III)–water and copper(I) chloride bridged by 4‐(pyridin‐4‐yl)benzoate ligands. Extensive hydrogen‐bonding interactions involving both the coordinated and the solvent water molecules provide further stabilization to the structure.     

A new two‐dimensional CoII coordination polymer based on bis[4‐(2‐methyl‐1H‐imidazol‐1‐yl)phenyl] ether and biphenyl‐4,4′‐diyldicarboxylic acid: synthesis,crystal structure and photocatalytic degradation activity

A novel two‐dimensional Co^II coordination framework, namely poly[(μ₂‐biphenyl‐4,4′‐diyldicarboxylato‐κ²O⁴:O^4′){μ₂‐bis[4‐(2‐methyl‐1H‐imidazol‐1‐yl)phenyl] ether‐κ²N³:N^3′}cobalt(II)], [Co(C₁₄H₈O₄)(C₂₀H₁₈N₄O)]_n, has been prepared and characterized by IR, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. The crystal structure reveals that the compound has an achiral two‐dimensional layered structure based on opposite‐handed helical chains. In addition, it exhibits significant photocatalytic degradation activity for the degradation of methylene blue.     

Two novel lanthanide(III) organic frameworks based on a biphenyltetracarboxylate ligand: synthesis,structure and magnetic and luminescence properties

Two new two‐dimensional lanthanide coordination polymers, namely poly[[tetra‐μ₂‐acetato‐tetraaquabis(μ₄‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraterbium(III)] pentahydrate], {[Tb₄(C₁₆H₆O₈)₂(C₂H₃O₂)₄(C₄H₉NO)₄(H₂O)₄]·5H₂O}_n, (1), and poly[[tetra‐μ₂‐acetato‐tetraaquabis(μ₅‐biphenyl‐3,3′,5,5′‐tetracarboxylato)tetrakis(dimethylacetamide)tetraeuropium(III)] tetrahydrate], {[Eu₄(C₁₆H₆O₈)₂(C₂H₃O₂)₄(C₄H₉NO)₄(H₂O)₄]·4H₂O}_n, (2), have been synthesized from biphenyl‐3,3′,5,5′‐tetracarboxylic acid (H₄bpt) and Ln(NO₃)₃·6H₂O (Ln = Tb and Eu) under solvothermal conditions. Single‐crystal X‐ray structure analysis shows that the two compounds are isostructural and crystallize in the monoclinic P2₁/n space group. The crystal structures are constructed from bpt⁴⁻ ligands (as linkers) and {Ln₂(μ₂‐CH₃COO)₂} building units (as nodes), which topological analysis shows to be a (4,6)‐connected network with sql topology. Compounds (1) and (2) have been characterized by elemental analysis, IR spectroscopy, powder X‐ray diffraction (PXRD), thermogravimetric analysis (TGA) and fluorescence analysis in the solid state. In addition, a magnetic investigation shows the presence of antiferromagnetic interactions in compound (1).     

Synthesis,crystal structure and photoluminescence of a three‐dimensional zinc coordination compound with NBO‐type topology

The assembly of metal–organic frameworks (MOFs) with metal ions and organic ligands is currently attracting considerable attention in crystal engineering and materials science due to their intriguing architectures and potential applications. A new three‐dimensional MOF, namely poly[[diaqua(μ₈‐para‐terphenyl‐3,3′,5,5′‐tetracarboxylato)dizinc(II)] dimethylformamide disolvate monohydrate], {[Zn₂(C₂₂H₁₀O₈)(H₂O)₂]·2C₃H₇NO·H₂O}_n, was synthesized by the self‐assembly of Zn(NO₃)₂·6H₂O and para‐terphenyl‐3,3′,5,5′‐tetracarboxylic acid (H₄TPTC) under solvothermal conditions. The compound was structurally characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction analysis. Each Zn^II ion is located in a square‐pyramidal geometry and is coordinated by four carboxylate O atoms from four different TPTC^4? ligands. Pairs of adjacent equivalent Zn^II ions are bridged by four carboxylate groups, forming [Zn₂(O₂CR)₄] (R = terphenyl) paddle‐wheel units. One aqua ligand binds to each Zn^II centre along the paddle‐wheel axis. Each [Zn₂(O₂CR)₄] paddle wheel is further linked to four terphenyl connectors to give a three‐dimensional framework with NBO‐type topology. The thermal stability and solid‐state photoluminescence properties of the title compound have also been investigated.     

Synthesis,structure and selective luminescence sensing for iron(III) ions of a three‐dimensional zinc(II) (4,6)‐connected coordination network

Coordination polymers constructed from conjugated organic ligands and metal ions with a d¹⁰ electronic configuration exhibit intriguing properties for chemical sensing and photochemistry. A Zn^II‐based coordination polymer, namely poly[aqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)(μ₂‐4,4′‐bipyridine)dizinc(II)], [Zn₂(C₁₆H₆O₈)(C₁₀H₈N₂)(H₂O)₂]_n or [Zn₂(m,m‐bpta)(4,4′‐bipy)(H₂O)₂]_n, was synthesized from a mixture of biphenyl‐3,3′,5,5′‐tetracarboxylic acid [H₄(m,m‐bpta)], 4,4′‐bipyridine (4,4′‐bipy) and Zn(NO₃)₂·6H₂O under solvothermal conditions. The title complex has been structurally characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis, and features a μ₆‐coordination mode. The Zn^II ions adopt square‐pyramidal geometries and are bridged by two syn–syn carboxylate groups to form [Zn₂(COO)₂] secondary buildding units (SBUs). The SBUs are crosslinked by (m,m‐bpta)^4? ligands to produce a two‐dimensional grid‐like layer that exhibits a stair‐like structure along the a axis. Adjacent layers are linked by 4,4′‐bipy ligands to form a three‐dimensional network with a {4⁴.6¹⁰.8}{4⁴.6²} topology. In the solid state, the complex displays a strong photoluminescence and an excellent solvent stability. In addition, the luminescence sensing results indicate a highly selective and sensitive sensing for Fe³⁺ ions.     

A bis(amine–carboxylate) copper(II) coordination compound forms a two‐dimensional metal–organic framework when crystallized from water and methanol

When {2,2′‐[(2‐methyl‐2‐nitropropane‐1,3‐diyl)diimino]diacetato}copper(II), [Cu(C₈H₁₃N₃O₆)], (I), was crystallized from a binary mixture of methanol and water, a monoclinic two‐dimensional water‐ and methanol‐solvated metal–organic framework (MOF) structure, distinctly different from the known orthorhombic one‐dimensional coordination polymer of (I), was isolated, namely catena‐poly[[copper(II)‐μ₃‐2,2′‐[(2‐methyl‐2‐nitropropane‐1,3‐diyl)diimino]diacetato] methanol 0.45‐solvate 0.55‐hydrate], {[Cu(C₈H₁₃N₃O₆)]·0.45CH₃OH·0.55H₂O}_n, (II). The monoclinic structure of (II) comprises centrosymmetric dimers stabilized by a dative covalent Cu₂O₂ core and intramolecular N—H...O hydrogen bonds. Each dimer is linked to four neighbouring dimers via symmetry‐related (opposing) pairs of bridging carboxylate O atoms to generate a `diamondoid' net or two‐dimensional coordination network. Tight voids of 166 ų are located between these two‐dimensional MOF sheets and contain a mixture of water and methanol with fractional occupancies of 0.55 and 0.45, respectively. The two‐dimensional MOF sheets have nanometre‐scale spacings (11.2 Å) in the crystal structure. Hydrogen‐bonding between the methanol/water hydroxy groups and a Cu‐bound bridging carboxylate O atom apparently negates thermal desolvation of the structure below 358 K in an uncrushed crystal of (II).     

Two CoII coordination polymers of biphenyl‐2,2′,5,5′‐tetracarboxylic acid with flexible N‐donor ligands: syntheses,structures and magnetic properties

Two Co^II‐based coordination polymers, namely poly[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato){μ₂‐1,3‐bis[(1H‐imidazol‐1‐yl)methyl]benzene}dicobalt(II)], [Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]_n or [Co₂(o,m‐bpta)(1,3‐bimb)₂]_n ( I ), and poly[[aqua(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato){1,4‐bis[(1H‐imidazol‐1‐yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂(H₂O)₂]·4H₂O}_n or {[Co₂(o,m‐bpta)(1,4‐bimb)₂(H₂O)₂]·4H₂O}_n ( II ), were synthesized from a mixture of biphenyl‐2,2′,5,5′‐tetracarboxylic acid, i.e. [H₄(o,m‐bpta)], CoCl₂·6H₂O and N‐donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis. The bridging (o,m‐bpta)^4? ligands combine with Co^II ions in different μ₄‐coordination modes, leading to the formation of one‐dimensional chains. The central Co^II atoms display tetrahedral [CoN₂O₂] and octahedral [CoN₂O₄] geometries in I and II , respectively. The bis[(1H‐imidazol‐1‐yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect Co^II ions, thus forming two three‐dimensional (3D) networks. Complex I shows a (2,4)‐connected 3D network with left‐ and right‐handed helical chains constructed by (o,m‐bpta)^4? ligands. Complex II is a (4,4)‐connected 3D novel network with ribbon‐like chains formed by (o,m‐bpta)^4? linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co…Co distances. An attempt has been made to fit the χ_MT results to the magnetic formulae for mononuclear Co^II complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the Co^II ions.     

1:1 Adducts of 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid with dimethylammonium and 4,4′‐bipyridine

The title compounds, dimethylammonium 2‐{4‐[1‐(4‐carboxymethoxyphenyl)‐1‐methylethyl]phenoxy}acetate, C₂H₈N⁺·C₁₉H₁₉O₆⁻, (I), and 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid–4,4′‐bipyridine (1/1), C₁₉H₂₀O₆·C₁₀H₈N₂, (II), are 1:1 adducts of 2,2′‐[isopropylidenebis(p‐phenyleneoxy)]diacetic acid (H₂L) with dimethylammonium or 4,4′‐bipyridine. The component ions in (I) are linked by N—H...O, O—H...O and C—H...O hydrogen bonds into continuous two‐dimensional layers parallel to the (001) plane. Adjacent layers are stacked via C—H...O hydrogen bonds into a three‐dimensional network with an –ABAB– alternation of the two‐dimensional layers. In (II), two H₂L molecules, one bipy molecule and two half bipy molecules are linked by O—H...N hydrogen bonds into one‐dimensional chains and rectanglar‐shaped rings. They are assembled viaπ–π stacking interactions and C—H...O hydrogen bonds into an intriguing zero‐dimensional plus one‐dimensional poly(pseudo)rotaxane motif.     

A series of two‐dimensional lanthanide coordination polymers: synthesis,structures, magnetism and selective luminescence detection for heavy metal ions and toxic solvents

A series of two‐dimensional (2D) coordination polymers (CPs), namely poly[[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)digadolinium(III)] N,N‐dimethylacetamide monosolvate], {[Gd₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]·C₄H₉NO}_n ( CP1 ), poly[[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)didysprosium(III)] N,N‐dimethylacetamide monosolvate], {[Dy₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]·C₄H₉NO}_n ( CP2 ), poly[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)dineodymium(III)], [Nd₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]_n ( CP3 ), poly[bis(μ‐acetato)diaqua(μ₆‐biphenyl‐3,3′,5,5′‐tetracarboxylato)bis(N,N‐dimethylacetamide)disamarium(III)], [Sm₂(C₁₆H₆O₈)(C₂H₃O₂)₂(C₄H₉NO)₂(H₂O)₂]_n ( CP4 ), has been synthesized from rigid biphenyl‐3,3′,5,5′‐tetracarboxylic acid under solvothermal conditions. Their structures have been determined by single‐crystal X‐ray diffraction analyses, elemental analyses, IR spectra, powder X‐ray diffraction and thermogravimetric analyses, and CP1 – CP4 crystallize in the monoclinic space group P2₁/n. CP1 – CP4 are isomorphous and feature similar 2D double layers, which are further extended via interlayer hydrogen‐bonding interactions into a three‐dimensional (3D) supramolecular structure. Hydrogen‐bonding interactions between N,N‐dimethylacetamide molecules and carboxylate O atoms strengthen the packing of the layers. The organic ligands interconnect with metal ions to generate 2D layered structures with a (4,4)‐connected net having {4⁴.6²} topology. CP1 has been investigated for its magnetic properties and magnetic susceptibility measurements were carried out in the range 2.0–300 K. The results of the magnetic measurements show weak antiferromagnetic coupling between the Gd^III ions in CP1 . Moreover, the strong luminescence of CP2 and CP4 can be selectively quenched by the Fe³⁺ ion and toxic solvents (e.g. acetone).     

Two new NiII and ZnII metal–organic frameworks of glutarate and 1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene ligands: syntheses,structures and luminescence sensing properties

Two new metal–organic frameworks (MOFs), namely, three‐dimensional poly[diaquabis{μ₂‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}bis(μ₂‐glutarato)dinickel(II)] monohydrate], {[Ni₂(C₅H₆O₄)₂(C₁₆H₁₈N₄)₂(H₂O)₂]·H₂O}_n or {[Ni₂(Glu)₂(1,4‐mbix)₂(H₂O)₂]·H₂O}_n, ( I ), and two‐dimensional poly[[{μ₂‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}(μ₂‐glutarato)zinc(II)] tetrahydrate], {[Zn(C₅H₆O₄)(C₁₆H₁₈N₄)]·4H₂O}_n or {[Zn(Glu)(1,4‐mbix)]·4H₂O}_n ( II ), have been synthesized hydrothermally using glutarate (Glu^2?) mixed with 1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene (1,4‐mbix), and characterized by single‐crystal X‐ray diffraction, IR and UV–Vis spectroscopy, powder X‐ray diffraction, and thermogravimetric and photoluminescence analyses. Ni^II MOF ( I ) shows a 4‐connected 3D framework with point symbol 6⁶, but is not a typical dia network. Zn^II MOF ( II ) displays a two‐dimensional 4⁴‐ sql network with one‐dimensional water chains penetrating the grids along the c direction. The solid‐state photoluminescence analysis of ( II ) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe³⁺ and Cr₂O₇^2? ions in aqueous solution.     

Synthesis,structure and photocatalytic degradation of organic dyes of a copper(II) metal–organic framework (Cu–MOF) with a 4‐coordinated three‐dimensional CdSO4 topology

Metal–organic frameworks (MOFs) have attracted much interest in the fields of gas separation and storage, catalysis synthesis, nonlinear optics, sensors, luminescence, magnetism, photocatalysis gradation and crystal engineering because of their diverse properties and intriguing topologies. A Cu–MOF, namely poly[[(μ₂‐succinato‐κ²O:O′){μ₂‐tris[4‐(1,2,4‐triazol‐1‐yl)phenyl]amine‐κ²N:N′}copper(II)] dihydrate], {[Cu(C₄H₄O₄)(C₂₄H₁₈N₁₀)]·2H₂O}_n or {[Cu(suc)(ttpa)]·2H₂O}_n, (I), was synthesized by the hydrothermal method using tris[4‐(1,2,4‐triazol‐1‐yl)phenyl]amine (ttpa) and succinate (suc^2?), and characterized by IR, powder X‐ray diffraction (PXRD), luminescence, optical band gap and valence band X‐ray photoelectron spectroscopy (VB XPS). Cu–MOF (I) shows a twofold interpenetrating 4‐coordinated three‐dimensional CdSO₄ topology with point symbol {6⁵·8}. It presents good photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB) under visible‐light irradiation. A photocatalytic mechanism was proposed and confirmed.     

One‐pot concomitant preparation of two copper(II) coordination polymers with different configurations of bridging bithiophene ligands

By employing the conjugated bithiophene ligand 5,5′‐bis(1H‐imidazol‐1‐yl)‐2,2′‐bithiophene (bibp), which can exhibit trans and cis conformations, two different Cu^II coordination polymers, namely, poly[[μ‐5,5′‐bis(1H‐imidazol‐1‐yl)‐2,2′‐bithiophene‐κ²N:N′](μ₂‐4,4′‐oxydibenzoato‐κ²O:O′)copper(II)], [Cu(C₁₄H₈O₅)(C₁₄H₁₀N₄S₂)]_n or [Cu(bibp)(oba)]_n, (I), and catena‐poly[μ‐aqua‐bis[μ‐5,5′‐bis(1H‐imidazol‐1‐yl)‐2,2′‐bithiophene‐κ²N:N′]bis(μ₃‐4,4′‐oxydibenzoato)‐κ³O:O′:O′′;κ⁴O:O′,O′′:O′‐dicopper(II)], [Cu₂(C₁₄H₈O₅)₂(C₁₄H₁₀N₄S₂)(H₂O)]_n or [Cu₂(bibp)(oba)₂(H₂O)]_n, (II), have been prepared through one‐pot concomitant crystallization and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, elemental analysis, powder X‐ray diffraction (PXRD) and thermogravimetric (TG) analysis. Single‐crystal X‐ray diffraction indicates that the most interesting aspect of the structure is the existence of sole trans and cis conformations of the bibp ligand in a single net of (I) and (II), respectively. Compound (I) displays a threefold interpenetrating three‐dimensional framework with a 4‐connected {6⁵.8} cds topology, whereas (II) features a one‐dimensional chain structure. In the crystal of (II), the polymeric chains are further extended through C—H…O hydrogen bonds and C—H…π interactions into a three‐dimensional supramolecular architecture. In addition, strong intramolecular O—H…O hydrogen bonds formed between the bridging water molecules and the carboxylate O atoms improve the stability of the framework of (II). Furthermore, solid‐state UV–Vis spectroscopy experiments show that compounds (I) and (II) exhibit optical band gaps which are characteristic for optical semiconductors, with values of 2.70 and 2.26 eV, respectively.     

Solvent Molecule Controlled Zinc(II) Metal‐Organic Frameworks with Different Topology

Two zinc(II) coordination polymers, namely [Zn₂(bptc)(DMF)₂(H₂O)]_n ( 1 ) and [Zn(bptc)_0.5(DMA)]_n ( 2 ) (H₄bptc = biphenyl‐3,3′,5,5′‐tetracarboxylic acid, DMF = N,N′‐dimethylformamide, DMA = N,N′‐dimethylacetamide), were obtained under solvothermal conditions by varying the reaction solvents. Single crystal X‐ray diffraction analyses revealed that compound 1 features a 3D PtS type framework based on dinuclear [Zn₂O(COO)₂] subunits and compound 2 features a 3D lvt type framework based on paddle‐wheel shaped [Zn₂(COO)₄] subunits. Moreover, the luminescent and thermal stabilities of these two compounds were investigated.     

Biphase synthesis of a one‐dimensional coordination polymer based on a dinuclear CdII secondary building unit and a novel semi‐rigid dicarboxylate

A one‐dimensional coordination polymer, namely catena‐poly[[aquapyridinecadmium(II)]‐μ₃‐{4,4′‐[(2,4,6‐trimethyl‐1,3‐phenylene)bis(methylene)]dibenzoato}], [Cd(C₂₅H₂₂O₄)(C₅H₅N)(H₂O)]_n, has been synthesized by a biphasic solvothermal reaction. The Cd^II cation is located in a CdO₅N six‐coordinated environment. The trans 4,4′‐[(2,4,6‐trimethyl‐1,3‐phenylene)bis(methylene)]dibenzoate ligand connects the Cd^II cations to form a one‐dimensional ribbon incorporating centrosymmetric [Cd₂(COO)₂] secondary building units. Inter‐ribbon O—H...O hydrogen bonds extend the one‐dimensional ribbons into a two‐dimensional sheet. No π–π interactions are observed. Comparing products synthesized using a different method, it was found that biphasic solvothermal conditions play a crucial role in obtaining large well‐shaped single crystals; only intractable precipitates were obtained by the traditional single‐phase solvothermal method.     

Two ZnII‐based MOFs constructed with biphenyl‐2,2′,5,5′‐tetracarboxylic acid and flexible N‐donor ligands: syntheses,structures and properties

Two new Zn²⁺‐based metal–organic frameworks (MOFs) based on biphenyl‐2,2′,5,5′‐tetracarboxylic acid, i.e. H₄(o,m‐bpta), and N‐donor ligands, namely, poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·C₃H₇NO·2H₂O}_n or {[Zn₂(o,m‐bpta)(1,3‐bimb)₂]·C₃H₇NO·2H₂O}_n ( 1 ) {1,3‐bimb = [1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}, and poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] monohydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·H₂O}_n or {[Zn₂(o,m‐bpta)(1,4‐bimb)₂]·H₂O}_n ( 2 ) {1,4‐bimb = [1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis. Structurally, the (o,m‐bpta)^4? ligands are fully deprotonated and combine with Zn²⁺ ions in μ₄‐coordination modes. Complex 1 is a (3,4)‐connected porous network with honeycomb‐like [Zn₂(o,m‐bpta)]_n sheets formed by 4‐connected (o,m‐bpta)^4? ligands. Complex 2 exhibits a (2,4)‐connected network formed by 4‐connected (o,m‐bpta)^4? ligands linking Zn²⁺ ions in left‐handed helical chains. The cis‐configured 1,3‐bimb and 1,4‐bimb ligands bridge Zn²⁺ ions to form multi‐membered [Zn₂(bimb)₂] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H₄(o,m‐bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C_2v polar point group.     

The heterometallic cadmium–silver complex cis‐bis[dicyanidoargentato(I)‐κN]bis(5,5′‐dimethyl‐2,2′‐bipyridyl‐κ2N,N′)cadmium(II) monohydrate

In the title complex, [Ag₂Cd(CN)₄(C₁₂H₁₂N₂)₂]·H₂O or cis‐[Cd{Ag(CN)₂}₂(5,5′‐dmbpy)₂]·H₂O, where 5,5′‐dmbpy is 5,5′‐dimethyl‐2,2′‐bipyridyl, the asymmetric unit consists of a discrete neutral [Cd{Ag(CN)₂}₂(5,5′‐dmbpy)₂] unit and a solvent water molecule. The Cd^II cation is coordinated by two bidentate chelate 5,5′‐dmbpy ligands and two monodentate [Ag^I(CN)₂]⁻ anions, which are in a cis arrangement around the Cd^II cation, leading to an octahedral CdN₆ geometry. The overall structure is stabilized by a combination of intermolecular hydrogen bonding, and Ag^I...Ag^I and π–π interactions, forming a three‐dimensional supramolecular network.