Synthesis,characterization and crystal structure of the new pentahydrate of bis(2,2′‐bipyridine‐κ2N,N′)(oxalato‐κ2O1,O2)nickel(II)

The reaction of NiCl₂, K₂C₂O₄·H₂O and 2,2′‐bipyridine (bpy) in water–ethanol solution at 281 K yields light‐purple needles of the new pentahydrate of bis(2,2′‐bipyridine)oxalatonickel(II), [Ni(C₂O₄)(C₁₀H₈N₂)₂]·5H₂O or [Ni(ox)(bpy)₂]·5H₂O, while at room temperature, deep‐pink prisms of the previously reported tetrahydrate [Ni(ox)(bpy)₂]·4H₂O [Román, Luque, Guzmán‐Miralles & Beitia (1995), Polyhedron, 14 , 2863–2869] were gathered. The asymmetric unit in the crystal structure of the new pentahydrate incorporates the discrete molecular complex [Ni(ox)(bpy)₂] and five solvent water molecules. Within the complex molecule, all three ligands are bonded as chelates. The complex molecules are involved in an extended system of hydrogen bonds with the solvent water molecules. Additionally, π–π interactions also contribute to the stabilization of the extended structure. The dehydration of the pentahydrate starts at 323 K and proceeds in at least two steps as determined by thermal analysis.     

Three‐Component Self‐Assembly of a Series of Triply Interlocked Pd12 Coordination Prisms and Their Non‐Interlocked Pd6 Analogues

Template‐assisted formation of multicomponent Pd₆ coordination prisms and formation of their self‐templated triply interlocked Pd₁₂ analogues in the absence of an external template have been established in a single step through Pd? N/Pd? O coordination. Treatment of cis‐[Pd(en)(NO₃)₂] with K₃tma and linear pillar 4,4′‐bpy (en=ethylenediamine, H₃tma=benzene‐1,3,5‐tricarboxylic acid, 4,4′‐bpy=4,4′‐bipyridine) gave intercalated coordination cage [{Pd(en)}₆(bpy)₃(tma)₂]₂[NO₃]₁₂ ( 1 ) exclusively, whereas the same reaction in the presence of H₃tma as an aromatic guest gave a H₃tma‐encapsulating non‐interlocked discrete Pd₆ molecular prism [{Pd(en)}₆(bpy)₃(tma)₂(H₃tma)₂][NO₃]₆ ( 2 ). Though the same reaction using cis‐[Pd(NO₃)₂(pn)] (pn=propane‐1,2‐diamine) instead of cis‐[Pd(en)(NO₃)₂] gave triply interlocked coordination cage [{Pd(pn)}₆(bpy)₃(tma)₂]₂[NO₃]₁₂ ( 3 ) along with non‐interlocked Pd₆ analogue [{Pd(pn)}₆(bpy)₃(tma)₂](NO₃)₆ ( 3′ ), and the presence of H₃tma as a guest gave H₃tma‐encapsulating molecular prism [{Pd(pn)}₆(bpy)₃(tma)₂(H₃tma)₂][NO₃]₆ ( 4 ) exclusively. In solution, the amount of 3′ decreases as the temperature is decreased, and in the solid state 3 is the sole product. Notably, an analogous reaction using the relatively short pillar pz (pz=pyrazine) instead of 4,4′‐bpy gave triply interlocked coordination cage [{Pd(pn)}₆(pz)₃(tma)₂]₂[NO₃]₁₂ ( 5 ) as the single product. Interestingly, the same reaction using slightly more bulky cis‐[Pd(NO₃)₂(tmen)] (tmen=N,N,N′,N′‐tetramethylethylene diamine) instead of cis‐[Pd(NO₃)₂(pn)] gave non‐interlocked [{Pd(tmen)}₆(pz)₃(tma)₂][NO₃]₆ ( 6 ) exclusively. Complexes 1 , 3 , and 5 represent the first examples of template‐free triply interlocked molecular prisms obtained through multicomponent self‐assembly. Formation of the complexes was supported by IR and multinuclear NMR (¹H and ¹³C) spectroscopy. Formation of guest‐encapsulating complexes ( 2 and 4 ) was confirmed by 2D DOSY and ROESY NMR spectroscopic analyses, whereas for complexes 1 , 3 , 5 , and 6 single‐crystal X‐ray diffraction techniques unambiguously confirmed their formation. The gross geometries of H₃tma‐encapsulating complexes 2 and 4 were obtained by universal force field (UFF) simulations.     

A d10 Metal Coordination Polymer Containing a Thiodiphthalic Ligand: Crystal Structure and Luminescent Property

A new two‐dimensional metal‐organic coordination polymer [Cd₂(2,3,2′,3′‐sdpa)(H₂O)₃] · 2H₂O ( 1 ) were hydro(solvo)thermally synthesized by the reaction of 2,3,2′,3′‐sulfonyldiphthalic acid (2,3,2′,3′‐H₄sdpa) with Cd(NO₃)₂ · 4H₂O and characterized by elemental analysis, thermogravimetry, IR and luminescence spectroscopy, and X‐ray diffraction. In complex 1 , two kinds of cadmium atoms are linked together by anionic sdpa^4– ligands to form a 2D metal‐organic network. The adjacent 2D layers further interact with each other through hydrogen bonds and π ··· π interactions to form a 3D supramolecular structure. The luminescence spectra and thermal properties of 1 were also investigated.     

Synthesis,crystal structure and magnetic properties of (acetato‐κ2O,O′)bis(5,5′‐dimethyl‐2,2′‐bipyridine‐κ2N,N′)nickel(II) perchlorate monohydrate

The title hydrated ionic complex, [Ni(CH₃COO)(C₁₂H₁₂N₂)₂]ClO₄·H₂O or [Ni(ac)(5,5′‐dmbpy)₂]ClO₄·H₂O (where 5,5′‐dmbpy is 5,5′‐dimethyl‐2,2′‐bipyridine and ac is acetate), (1), was isolated as violet crystals from the aqueous ethanolic nickel acetate–5,5′‐dmbpy–KClO₄ system. Within the complex cation, the Ni^II atom is hexacoordinated by two chelating 5,5′‐dmbpy ligands and one chelating ac ligand. The mean Ni—N and Ni—O bond lengths are 2.0628 (17) and 2.1341 (15) Å, respectively. The water solvent molecule is disordered over two partially occupied positions and links two complex cations and two perchlorate anions into hydrogen‐bonded centrosymmetric dimers, which are further connected by π–π interactions. The magnetic properties of (1) at low temperatures are governed by the action of single‐ion anisotropy, D, which arises from the reduced local symmetry of the cis‐NiO₂N₄ chromophore. The fitting of the variable‐temperature magnetic data (2–300 K) gives g_iso = 2.134 and D/hc = 3.13 cm⁻¹.     

Effect of Metal Ions on the Structures of Coordination Polymers Based on Biphenyl‐2,2′,4,4′‐Tetracarboxylate

Two new coordination polymers, {[Cd₂(btc)(2,2′‐bpy)₂] · H₂O}_n ( 1 ) and [Zn₂(btc)(2,2′‐bpy)(H₂O)]_n ( 2 ) (H₄btc = biphenyl‐2,2′,4,4′‐tetracarboxylic acid, 2,2′‐bpy = 2,2′‐bipyridine), were synthesized hydrothermally under similar conditions and characterized by elemental analysis, IR spectra, TGA, and single‐crystal X‐ray diffraction analysis. In complexes 1 and 2 , the (btc)^4– ligand acts as connectors to link metal ions to give a 2D bilayer network of 1 and a 3D metal‐organic framework of 2 , respectively. The differences in the structures are induced by diverging coordination modes of the (btc)^4– ligand, which can be attributed to the difference metal ions in sizes. The results indicate that metal ions have significant effects on the formation and structures of the final complexes. Additionally, the fluorescent properties of the two complexes were also studied in the solid state at room temperature.     

Cadmium(II) Complexes with Mixed cis‐Epoxysuccinate and 2,2′‐Bipyridyl‐Like Ligands: Syntheses,Crystal Structures,and Luminescent Properties

Two new Cd^II complexes, [Cd( ces )(phen)]_∞ ( 1 ) and {[Cd( ces )(bpy)(H₂O)](H₂O)}₂ ( 2 ), were prepared by slow solvent evaporation methods from mixtures of cis‐epoxysuccinic acid and Cd(ClO₄)₂ · 6H₂O in the presence of phen or bpy co‐ligand ( ces = cis‐epoxysuccinate, phen = 1,10‐phenanthroline, and bpy = 2,2′‐bipyridine). Single‐crystal X‐ray diffraction analyses show that complex 1 has a one‐dimensional (1D) helical chain that is further assembled into a two‐dimensional (2D) sheet, and then an overall three‐dimensional (3D) network by the interchain C–H ··· O hydrogen bonds. Complex 2 features a dinuclear structure, which is further interlinked into a 3D supramolecular network by the co‐effects of intermolecular C–H ··· O and C–H ··· π hydrogen bonds as well as π ··· π stacking interactions. The structural differences between 1 and 2 are attributable to the intervention of different 2,2′‐bipyridyl‐like co‐ligands. Moreover, 1 and 2 exhibit intense solid‐state luminescence at room temperature, which mainly originates from the intraligand π→π* transitions of aromatic co‐ligands.     

Supramolecular Architectures with Open Frameworks Constructed by Transitional Metal Ions,Linear Dicarboxylic Acid,and 2,2′‐Bipyridine

Four new transitional metal supramolecular architectures, [Zn(cca)(2,2′‐bpy)]_n · n(2,2′‐bpy) ( 1 ), [Cu(cca)(2,2′‐bpy)]_n ( 2 ), [Zn(bpdc)(2,2′‐bpy)(H₂O)]_n · 0.5nDMF · 1.5nH₂O ( 3 ), and [Co(bpdc)(2,2′‐bpy)(H₂O)]_n · nH₂O ( 4 ) (H₂cca = p‐carboxycinnamic acid; H₂bpdc = 4,4′‐biphenyldicarboxylic acid; 2,2′‐bpy = 2,2′‐bipyridine) were synthesized by hydrothermal reactions and characterized by single crystal X‐ray diffraction, elemental analyses, and IR spectroscopy. Although the metal ions in these four compounds are bridged by linear dicarboxylic acid into 1D infinite chains, there are different π–π stacking interactions between the chains, which results in the formation of different 3D supramolecular networks. Compound 1 is of a 3D open‐framework with free 2,2′‐bpy molecules in the channels, whereas compound 2 is of a complicated 3D supramolecular network. Compounds 3 and 4 are isostructural. Both compounds have open‐frameworks.     

A 2D Supramolecular Network Based on Aromatic π···π Stacking Interactions

Using ferrocenecarboxylic acid (FcCOOH) as organometallic ligand in the synthesis of heterometallic complexes led to the isolation of the compound [(FcCOO)Cu(bpy)₂](BF₄) · bpy · CH₃OH. It was characterized by IR spectroscopy, EA, powder XRD, UV, and TGA measurements. Single‐crystal X‐ray structural analysis revealed that a unique 2D supramolecular network purely formed by aromatic π ··· π stacking interactions was observed, namely, {[(FcCOO)Cu(bpy)₂](BF₄) · bpy · CH₃OH}_∞ ( 1 ). The solid UV/Vis diffuse reflectance spectrum revealed the optical energy gap of 1 to be 3.54 eV, which is dramatically blue shifted compared with the value of ferrocene. Experimental results of thermal analysis and electrochemical analysis show that 1 has good thermal and better electrochemical stability.     

A New Succinato‐bridged Supramolecular Helix Chain: Crystal Structure of [Mn(H2O)2(bpy)(C4H4O4)] · H2O with bpy = 2,2′‐bipyridine

Yellow crystals of [Mn(H₂O)₂(bpy)(C₄H₄O₄)] · H₂O were obtained by the reaction of 2,2′‐bipyridine, succinic acid, MnSO₄ · H₂O and Na₂CO₃ in an aqueous methanol solution. The crystal structure (monoclinic, P2₁/c (no. 14), a = 8.294(1), b = 11.556(1), c = 17.064(1)Å, β = 95.181(6)°, Z = 4, R = 0.0349, wR² = 0.0887) consists of 1D supramolecular helix chains [Mn(H₂O)₂(bpy)(C₄H₄O₄)_2/2] and hydrogen bonded H₂O molecules. The Mn atoms are octahedrally coordinated by two N atoms of one bidentate chelating bpy ligand and four O atoms of two H₂O molecules and two bis‐monodentate bridging succinato ligands with d(Mn–O) = 2.139–2.237Å and d(Mn–N) = 2.268, 2.281 Å. The helix chains are held together by π‐π stacking interactions and hydrogen bonds.     

Crystal Structures of [Mn2(H2O)4(bpy)2(C8H12O4)2] · 2 H2O and [Mn(H2O)2(bpy)(C8H12O4)2/2] · H2O with bpy = 2,2′‐bipyridine

Reaction of MnSO₄ · H₂O, 2,2′‐bipyridine (bpy), suberic acid and Na₂CO₃ in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] · 2 H₂O ( 1 ) and [Mn(H₂O)₂‐ (bpy)(C₈H₁₂O₄)_2/2] · H₂O ( 2 ). In both complexes, the Mn atoms are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two trans positioned H₂O molecules and two suberato ligands (d(Mn–O) = 2.107–2.328 Å; d(Mn–N) = 2.250–2.330 Å). The bis‐monodentate suberato ligands bridge Mn atoms to form dinuclear [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] complex molecules in 1 and 1D [Mn(H₂O)₂(bpy)(C₈H₁₂O₄)_2/2] chains in 2 . Via the intermolecular hydrogen bondings and π‐π stacking interactions, the dinuclear molecules in 1 are assembled into 2D networks parallel to (100), between which the crystal H₂O molecules are sandwiched. The polymeric chains in 2 are linked together by interchain hydrogen bonding and π‐π stacking interactions into 3D networks with the crystal H₂O molecules located in tunnels along [010]. Crystal data for 1 : P2₁/c (no. 14), a = 10.092(1) Å, b = 11.916(2) Å, c = 17.296(2) Å, β = 93.41(1)° and Z = 2. Crystal data for 2 : P2₁/c (no. 14), a = 11.176(2) Å, b = 9.688(1) Å, c = 37.842(6) Å, β = 90.06(1)° and Z = 8.     

DNA/BSA‐binding property and in vitro anticancer activity of a new dicopper(II) complex with N‐(2‐hydroxy‐5‐nitrophenyl)‐N′‐[3‐(diethylamino)propyl]oxamide as bridging ligand: Synthesis and crystal structure

A new oxamido‐bridged dicopper(II) complex formulated as [Cu₂(ndpox)(bpy)(CH₃OH)₂]‐ (ClO₄), where H₃ndpox is N‐(2‐hydroxy‐5‐nitrophenyl)‐N′‐[3‐(diethylamino)propyl]oxamide; and bpy represents 2,2′‐bipyridine, was synthesized and structurally characterized using X‐ray single‐crystal diffraction and other methods. In the molecule, the endo‐ and the exo‐copper(II) ions bridged by the cis ‐ndpox³⁻ ligand are in {N₃O₂} and {N₂O₃} square‐ pyramidal environments, respectively. There is a three‐dimensional hydrogen bonding network dominated by O‐H···O and C‐H···O interactions in the crystal. The reactivity toward DNA/protein bovine serum albumin (BSA) revealed that the complex could interact with herring sperm DNA (HS‐DNA) through the intercalation mode, and effectively quench the intrinsic fluorescence of BSA via a static process. Cytotoxicity studies suggest that the complex displays selective cancer cell antiproliferative activity. The present investigation confirmed that the combined effects of both electron‐withdrawing and hydrophobic groups on the bridging ligand in the dicopper(II) complex systems can increase DNA/BSA‐binding ability and in vitro anticancer activity.     

Synthesis,Structure, and Solution Study of a Mercury(II) Complex with the Ligand [1‐(2‐Methoxyphenyl)‐3‐(4‐chlorophenyl)]triazene

The title ligand, [1‐(2‐methoxyphenyl)‐3‐(4‐chlorophenyl)]triazene, H L ( 1 ), was prepared. In a reaction with Hg(NO₃)₂ it forms the complex [Hg(C₂₆H₂₂Cl₂N₆O₂)], [Hg L ₂] ( 2 ). Both compounds were characterized by means of X‐ray crystallography, CHN analysis, FT‐IR, ¹H NMR, and ¹³C NMR spectroscopy. In the structure of compound 1 , two independent fragments are present in the unit cell. They exhibit trans arrangement about the –N=N– double bond. The dihedral angles between two benzene rings in both fragments are 4.36 and 18.79 Å, respectively. Non‐classic C–H ··· N hydrogen bonding and C–H ··· π interactions form a layer structure along the crystallographic ab plane [110]. In compound 2 , the Hg^II atom is hexacoordinated by two tridentate [1‐(2‐methoxyphenyl)‐3‐(4‐chlorophenyl)]triazenide ligands through a N₂O₂ set. In addition, in the structure of 2 , monomeric complexes are connected to each other by C–H ··· π stacking interactions, resulting in a 2D architecture. These C–H ··· π edge‐to‐face interactions are present with H ··· π distances of 3.156 and 3.027 Å. The results of studies of the stoichiometry and formation of complex 2 in methanol solution were found to support its solid state stoichiometry.     

Syntheses and Crystal Structures of Two Metal Succinates Modified by Bipyridines

Two new metal succinates modified by rigid bipyridines, Cd(4, 4′‐bpy)(C₄H₄O₄)·1/4H₂O ( 1 ) and Cu(2, 2′‐bpy)(C₄H₄O₄)_0.5(NO₃)(H₂O) ( 2 ) (bpy = bipyridine), have been synthesized by hydrothermal reactions and structurally determined. Complex 1 crystallizes in the orthorhombic space group Cmca with the cell parameters a = 11.696(2), b = 15.554(2), c = 15.874(3) Å, α = β = γ = 90.00°, V = 2888(3) ų, Z = 8. Complex 2 crystallizes in the triclinic space group with a = 7.077(1), b = 9.838(2), c = 10.461(2) Å, α = 71.941(3)°, β = 73.078(3)°, γ = 74.502(3)°, V = 649.8(2) ų, Z = 2. In complex 1 , a 2‐D network was formed by Cd‐succinato bonding. The 2‐D networks are pillared by 4, 4′‐bpy ligands, forming a 3‐D grid framework. The 2‐fold interpenetration of the resulting 3‐D frameworks completes the molecular structure. In complex 2 , the Cu^II atom adopts a distorted octahedral in which the Cu^II atoms are bridged by two H₂O molecules into an infinite zigzag chain, [Cu₂(H₂O)₂(C₄H₄O₄)]_n. The neighboring chains are further linked by π‐π stacking interactions into a 2‐D network, and the interlayer hydrogen bonds lead to the final 3‐D crystal structure.     

A threefold interpenetrated two‐dimensional zinc(II) supramolecular architecture based on 3‐nitrobenzoic acid and 4,4′‐bipyridine

With regard to crystal engineering, building block or modular assembly methodologies have shown great success in the design and construction of metal–organic coordination polymers. The critical factor for the construction of coordination polymers is the rational choice of the organic building blocks and the metal centre. The reaction of Zn(OAc)₂·2H₂O (OAc is acetate) with 3‐nitrobenzoic acid (HNBA) and 4,4′‐bipyridine (4,4′‐bipy) under hydrothermal conditions produced a two‐dimensional zinc(II) supramolecular architecture, catena‐poly[[bis(3‐nitrobenzoato‐κ²O,O′)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′], [Zn(C₇H₄NO₄)₂(C₁₀H₈N₂)]_n or [Zn(NBA)₂(4,4′‐bipy)]_n, which was characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single‐crystal X‐ray diffraction analysis. The Zn^II ions are connected by the 4,4′‐bipy ligands to form a one‐dimensional zigzag chain and the chains are decorated with anionic NBA ligands which interact further through aromatic π–π stacking interactions, expanding the structure into a threefold interpenetrated two‐dimensional supramolecular architecture. The solid‐state fluorescence analysis indicates a slight blue shift compared with pure 4,4′‐bipyridine and HNBA.     

Synthesis,Crystal Structures,and Photoluminescence of Lanthanide Coordination Polymers with 4‐Acetamidobenzoate

The reactions of Ln(NO₃)₃ · 6H₂O and 4‐acetamidobenzoic acid (Haba) with 4,4′‐bipyridine (4,4′‐bpy) in ethanol solution resulted in three new lanthanide coordination polymers, namely {[Ln(aba)₃(H₂O)₂] · 0.5(4,4′‐bpy) · 2H₂O}_∞ [Ln = Sm ( 1 ), Gd ( 2 ), and Er ( 3 ), aba = 4‐acetamidobenzoate]. Compounds 1 – 3 are isomorphous and have one‐dimensional chains bridged by four aba anions. 4,4′‐Bipyridine molecules don’t take part in the coordination with Ln^III ions and occur in the lattice as guest molecules. Moreover, the adjacent 1D chains in the complex are further linked through numerous N–H ··· O and O–H ··· O hydrogen bonds to form a 3D supramolecular network. In addition, complex 1 in the solid state shows characteristic emission in the visible region at room temperature.     

Synthesis and Characterization of Two New Transition‐Metal Complex Salts of the Wells‐Dawson Polyanion

Two new transition‐metal (TM) complex salts of the Wells‐Dawson polyanion: [Cu(2,2′‐bpy)₃]₂[Cu(2,2′‐bpy)₂]₂[P₂W₁₈O₆₂] ( 1 ) and [2,2′‐bpy]₈[Fe(2,2′‐bpy)₃]₈[P₂W₁₈O₆₂]₄·9H₂O ( 2 ) (2,2′‐bpy = 2,2′‐bipyridine), have been synthesized under hydrothermal conditions by using pre‐prepared α‐K₆P₂W₁₈O₆₂·15H₂O as a precursor. Crystal data for compound 1 : monoclinic, space group C2/c, a = 20.722(4) Å, b = 21.988(4) Å, c = 29.614(6) Å, β = 104.32(3)°, V = 13074(5) ų, Z = 4; for compound 2 : triclinic, space group , a = 15.804(3) Å, b = 27.519(6) Å, c = 27.566(6) Å, α = 72.71(3)°, β = 89.94(3)°, γ = 89.90(3)°, V = 11447(5) ų, Z = 1. Compounds 1 and 2 have been characterized by single‐crystal X‐ray diffraction, IR spectra, thermogravimetric analysis, XPS spectra and cyclic voltammetry. The two compounds were used as solid bulk modifiers to fabricate bulk‐modified carbon paste electrodes ( 1 ‐, 2 ‐CPE). The electrochemical behaviors of 1 ‐, 2 ‐CPE have been studied in detail. The redox behavior of the parent Wells‐Dawson type cluster was maintained completely in compounds 1 and 2 .     

Influence of the Size of Aromatic Chelate Ligands on the Structures of Cadmium(II) Tetracarboxylates Polymers: From 2D Layered Network to 3D Metal‐Organic Framework

To determine the influence of the size of the aromatic chelate ligands on the frameworks of metal tretracarboxylate polymers, two new coordination polymers [Cd(btc)_0.5 (2,2′‐bpy)] ( 1 ) and [Cd(btc)_0.5(phen)]·H₂O ( 2 ) (H₄btc = biphenyl‐3,3′,4,4′‐tetracarboxylic acid, 2,2′‐bpy = 2,2′‐bipyridine, phen = 1,10‐phenanthroline) have been synthesized under similar hydrothermal conditions. In complex 1 , the dimeric Cd₂ units are linked by bridging btc^4? ligand to form a 2D layered network, whereas complex 2 possesses a 3D metal‐organic framework consisting of the dimeric Cd₂ units. The differences of two metal‐organic frameworks demonstrate that the size of the rigid aromatic chelate ligands have an important effect on the structures of their complexes. Additionally, the two complexes show strong fluorescence in the solid state at room temperature.     

Syntheses and Crystal Structures of Cadmium Complexes with Thiophenedicarboxylate and Bipyridine‐like Ligands

Two new coordination polymers [Cd(tdc)(bpy)(H₂O)]_n ( 1 ) and [Cd(tdc)(phen)]_n ( 2 ) (H₂tdc = thiophene‐2,5‐dicarboxylic acid, bpy = 2,2′‐bipyridine and phen = 1,10‐phenanthroline) have been synthesized under hydrothermal condition. Their crystal structures have been established by X‐ray single‐crystal diffraction. Complex 1 crystallizes in the orthorhombic space group Fdd2 with a = 14.757(7), b = 45.38(2), c = 10.518(5) Å, V = 7044(6) ų, Z = 16; 2 in the monoclinic space group P2₁/c with a = 7.262(1), b = 21.970(2), c = 10.051(1) Å, β = 105.01(1)°, V = 1548.8(2) ų, Z = 4. Both of them are double‐stranded chains and further assembled into three‐dimensional networks by π‐π stacking interactions. 1 and 2 are stable in air, and show blue photoluminescence at 415 nm and 410 nm, respectively.     

A New Polynuclear Copper‐Complex‐Substituted Tungstoarsenate(V)

A new polynuclear copper‐complex‐substituted dimeric tungstoarsenate(V), H₂[{Cu(2,2′‐bpy)}₈(H₂O)₂(AsW₉O₃₄)₂] · 12H₂O ( 1 ) (2,2′‐bpy = 2,2′‐bipydine), was synthesized hydrothermally and its structure was determined by single‐crystal X‐ray diffraction. The title compound has Ci symmetry and consists of two trilacunary Keggin anions [α‐AsW₉O₃₄]^9– supported by eight copper complex cations. The compound was also characterized by IR and fluorescence spectroscopy, TG analysis, and magnetic measurements. The emission spectrum of the compound in solid‐state exhibits a redshift relative to those of Na₈[A‐HAsW₉O₃₄] · 11H₂O and the free ligand 2,2′‐bpy. Magnetic measurements of the compound indicate competing ferro‐ and antiferromagnetic intramolecular coupling among the Cu^II atoms in the cluster anion.     

Syntheses,Crystal Structures,and Fluorescence Properties of Two Transition Metal‐Organic Coordination Polymers Based on 4,4′‐Dimethyl‐2,2′‐bipyridine

Two transition metal‐organic coordination polymers, [Mn₂(1,3‐bdc)₂(Me₂bpy)₂] · Me₂bpy ( 1 ) and [Co(4,4′‐oba)(Me₂bpy)] ( 2 ) were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, TG, and single‐crystal X‐ray diffraction [1,3‐H₂bdc = benzene‐1,3‐dicarboxylic acid, H₂oba = 4,4′‐oxybis(benzoic acid) Me₂bpy = 4,4′‐dimethyl‐2,2′‐bipyridine]. Compound 1 crystallizes in the orthorhombic system, space group P2₁2₁2₁, with a = 23.371(5), b = 14.419(3), and c = 14.251(3) Å. Compound 2 crystallizes in the monoclinic system, space group P2₁/c, with a = 7.4863(15), b = 18.272(4), c = 16.953(5) Å, and β = 107.44(3)°. The crystal structure of complex 1 is a wave‐like layer with central Mn²⁺ atoms bridged by 1,3‐bdc ligands, whereas the structure of compound 2 presents a ladder chain of hexacoordinate Co²⁺ atoms, in which the metal atoms are bridged by 4,4′‐oba ligands and decorated by Me₂bpy ligands. The two compounds are further extended into 3D supramolecular structures through π–π stacking interactions. Additionally, the compounds show intense fluorescence in solid state at room temperature.