A new (3,4,7)-connected topology framework based on [Cd2(CO2)3O4N2] second building unit

A new 3D coordination polymer [Cd₂(L³)(BTC)(H₂O)] (1) (HL³ = 3,5-bis(pyridin-3-ylmethoxy)benzoic acid, H₃BTC = 1,3,5-benzenetricarboxylic acid), has been isolated under hydrothermal condition and characterized by single-crystal X-ray diffraction. Compound 1 is constructed from Cd₂-based second building units (SBUs) [Cd₂(CO₂)₃O₄N₂] and displays a 3D (3,4,7)-connected net with (4²·6)(4³·6³)(4⁵·6¹¹·8⁵) topology. In addition, the photoluminescent spectra indicate compound 1 may be a good candidate for blue-luminescent materials.     

An oxide chain constructed from octamolybdate, a Keggin anion and a copper (II) – Tetrapyridylpyrazine binuclear unit

The hydrothermal reaction of MoO₃, CuSO₄·5H₂O, tetra-4-pyridylpyrazine (tpyprz), and diphenyldiarsonic acid in water at 140 °C for 48 h yielded the one-dimensional material [{Cu₂(tpyprz)(H₂O)₃}₂{Mo₈O₂₆}{Mo₁₂O₃₆(AsO₄)}]·8H₂O (1·8H₂O). The chain structure of 1·8H₂O is constructed from alternating β-octamolybdate clusters and molybdoarsonate Keggin clusters linked through {Cu₂(tpyprz)(H₂O)₃}⁴⁺ binuclear subunits. The Cu(II) sites are inequivalent with one copper bonding to two pyridyl donors and a pyrazine nitrogen of one terminus of the tpyprz ligand, two aqua ligands and an oxo-group of the cluster while the second copper site coordinates to the nitrogen donors of the other terminus of the tpyprz ligand, an aqua group, a terminal oxo-group of the cluster and a terminal oxo-group of the mixed valence {Mo₁₁^VIMo^VO₃₆(AsO₄)}⁴⁻ cluster. Crystal data: C₄₈H₆₀AsCu₄Mo₂₀N₁₂O₈₀: FW = 4332.96 Triclinic , a = 12.5087(5) Å, b = 13.6681(6) Å, c = 14.8980(6) Å, α = 92.196(1)°, β = 97.046(1)°, γ = 97.751(1)°, Z = 1, D_calc = 2.877 g cm⁻³; structure solution and refinement based on 12,333 reflections (Mo K_α, λ = 0.71073 Å) converged at R₁ = 0.0540 and wR₂ = 0.1115.     

pH Dependent formations of dinuclear molybdenum(V) and incomplete cubane molybdenum(IV) complexes with nitrilotriacetate

Nitrilotriacetato oxomolybdenum(V) dinuclear complex (NH₄)₄[cis-Mo₂O₄(nta)₂] · 7H₂O (1) (H₃nta = nitrilotriacetic acid) and its incomplete cubane-type trinuclear molybdenum(IV) complex [Mo₃O(OH)₃(Hnta)₃] · Cl · 3H₂O (2) are isolated in a weak acidic and an acidic solutions, respectively (pH 4.5 and 1.0). The nitrilotriacetate ligand in the anion 1 or the cation 2 displays tridentate mode through the nitrogen atom and the oxygen atoms of β-carboxy groups. Unusual protonations of bridged oxygen atoms in 2 have not effect on the skeleton of molybdenum(IV) cap Mo₃O unit. There are obvious dissociations of molybdenum(V) complexes based on ¹³C NMR observations in solution.     

Two novel Zn(II) coordination polymers based on trigonal ligand: 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine

Two novel Zn(II) coordination polymers, [Zn₅(pytpy)₈(fum)₄(H₂O)₄(OH)₂]_n · n(CH₃OH) · 2n(H₂O) (1) and [Zn₃(pytpy)₄ (btc)₂]_n · 2n(H₂O) (2) (pytpy = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine, H₂fum = fumaric acid, H₃btc = 1,3,5-benzenetricarboxylic acid) have been hydrothermally synthesized and structurally characterized. Complex 1 is a 2D layer structure, which is constructed from linear pentanuclear Zn(II) subunits interconnected via bidentate-bridging pytpy ligands and tridentate-bridging fum²⁻ anions. Complex 2 is a 3D network structure, μ₂-pytpy ligands link the layers based on the heart-like hexanuclear subunits to form the 3D network. Both complexes show strong fluorescence emission upon excitation at 310 nm in solid state. Additionally, these two complexes possess great thermal stabilities, especially for 2, the framework is stable up to 350 °C.     

A new type of supramolecular assembly consisting of crown ether complex cation and a polyoxometalate anion: Synthesis and crystal structure of [Na(C20H24O6)(CH3CN)2]2[Mo6O19] · 4CH3CN

A novel supramolecular assembly consisting of sodium-dibenzo-18-crown-6(DB18C6) complex cation [Na(C₂₀H₂₄O₆)(CH₃CN)₂]²⁺ and isopolyanion [Mo₆O₁₉]²⁻ has been demonstrated in the 3D structure of [Na(C₂₀H₂₄O₆)(CH₃CN)₂]₂[Mo₆O₁₉] · 4CH₃CN (1). Weak intermolecular forces (C–HO hydrogen bonds) between isopolyanion and crown ether play a significant role in the construction of supramolecular framework in the crystal structure of 1. Compound 1 has been characterized in the solid state by single crystal X-ray diffraction, IR, CHN analysis, and TGA.     

A photoluminescent 3D silver(I) polymer with mixed 2-naphthol-5-carboxylate and hexamethylenetetramine ligands,showing an unusual (3,4)-connected (6·7·8)2(4·6·7)2(4·7·8)2(72·8)2(62·7·83)(62·72·8·10) topology

The reaction of AgClO₄ with 2-naphthol-5-carboxylic acid (HL) and hexamethylenetetramine (hmt) in the presence of 2,6-dimethylpyridine afforded a photoluminescent three-dimensional (3D) Ag^I polymer {[Ag₆(L)(μ₃-hmt)₂(μ₄-hmt)₂(ClO₄)](ClO₄)₄(H₂O)}_∞ (1), which exhibited an unusual (3,4)-connected (6·7·8)₂(4·6·7)₂(4·7·8)₂(7²·8)₂(6²·7·8³)(6²·7²·8·10) topological network (L = 2-naphthol-5-carboxylate). Moreover, the luminescent properties of 1 have been briefly investigated.     

Preparation, crystal structure and properties of two novel metal-organic frameworks assembled from pyridine-3,5-dicarboxylic acid N-oxide

Two novel coordination polymers, [Cu(PDCO) · (H₂O)]_n (1) and [Cd(PDCO)(bipy) · (H₂O) · 5H₂O]_n (2), (H₂PDCO = pyridine-3,5-dicarboxylic acid N-oxide, bipy = 4,4′-bipyridine), have been synthesized under hydrothermal conditions, and their structures were determined by single-crystal X-ray diffraction studies. Polymer 1 features a three-dimensional (3D) network with nonequivalent nodes of (6³)₂(6⁹ · 8⁵ · 10) topology. Polymer 2 exhibits one-dimensional (1D) double-stranded chains. The magnetic character of 1 as well as the gas adsorption and luminescent properties of 2 have been investigated.     

In situ hydrolysis of 4-cyanopyridine in hydrothermal synthesis of a 3-D coordination polymer, {Pb(II)(C6H4O2N)2}n

A novel luminescent Pb(II) coordination framework, {Pb(II)(C₆H₄O₂N)₂}_n, have been prepared in situ hydrolysis of 4-cyanopyridine under hydrothermal condition and characterized by the elemental analyses, IR spectra, TG and single crystal X-ray diffraction. The compound presents the first framework compound constructed from isonicotinic acids and lead(II) ions, showing three-dimensional architecture with (4, 4) net self-penetrating (4⁸ 6⁷) topology.     

Reduction of n-C5H11N3 Catalyzed by [Mo2Fe6S8(OMe)3(SC6H4-p-n-C8H17)6]3– in an Aqueous Micellar Solution

Reduction of n-C₅H₁₁N₃ by Na₂S₂O₄ was performed in the presence of (n-Bu₄N)₃ [Mo₂Fe₆S₈(OMe)₃(SC₆H4-p-n-C₈H₁₇)₆] ((n-Bu₄N)₃ [Mo-Fe]) as a catalyst in aqueous Triton X-100 micellar solutions. The rate of the reduction is enhanced efficiently by the addition of methyl viologen (MV²⁺). The methyl viologen radical cation (MV⁺) produced by the reaction of MV²⁺ with Na₂S₂O₄ undergoes a disproportionation reaction to afford MV²⁺ and MV° in the micellar solution. The resultant MV° formed in the micelle transfers two electrons to [Mo-Fe]³⁻ effectively to give [Mo-Fe]⁵⁻, which reduces n-C₅H₁₁N₃ with two electrons to produce n-C₅H₁₁NH₂ and N₂.     

A novel 1D molybdenum oxide ribbon bridged by pyridine-4-carboxylic ligands: [(C6H4NO2) Mo2O5OH]

A novel 1D organic–inorganic hybrid compound [(C₆H₄NO₂)Mo₂O₅OH] 1 has been synthesized hydrothermally and characterized by single crystal X-ray diffraction, IR, and thermogravimetric analysis. The structure of [(C₆H₄NO₂)Mo₂O₅OH] consists of {MoO₆}octahedra and pyridine-4-carboxylic ligands. {MoO₆} octahedra share their adjacent equatorial edges, forming a new 1D ribbon-like molybdenum oxide framework. Pyridine-4-carboxylic ligands are bridged to the molybdenum sites up and down along the ribbon.     

Synthesis and structure of a high-nuclearity oxomolybdenum(V) complex, [Mo12O28(OC2H5)4(C6H7N)8]

(PyH)[MoOBr₄(H₂O)]·2/3PyHBr (PyH⁺=pyridinium cation, C₅H₅NH⁺) yielded upon the solvothermal reaction with ethanol and 4-methylpyridine (4-MePy, C₆H₇N) a novel oxoethoxomolybdenum(V) cluster, [Mo₁₂O₂₈(OC₂H₅)₄(4-MePy)₈] 1. Molybdenum atoms are grouped into six Mo^V₂ pairs linked by single metal–metal bonds. Three crystallographically independent Mo–Mo distances are 2.5578(14), 2.5981(14) and 2.6489(16) Å.     

Synthesis and structural characterization of an alternating double aquo-bridged and single cyano-bridged polymeric barium–iron complex: {[Ba2(phen)4(H2O)6Fe(CN)6]·Cl·2(phen)·3H2O}n

A new alternating double aquo-bridged and single cyano-bridged polymeric complex {[Ba₂(phen)₄(H₂O)₆Fe(CN)₆]·Cl·2(phen)·3H₂O}_n (1) (phen = 1,10-phenanthroline) has been synthesized and structurally characterized. In the crystal structure the two centrosymmetric [Ba₂(phen)₄(H₂O)₆] units are bridged through two trans CN groups of [Fe(CN)₆]³⁻ ion, which results in the formation of a zig-zag polymeric chain. In each [Ba₂(phen)₄(H₂O)₆] unit, the two Ba centers are joined by double aquo bridges. Both the Ba atoms are 9-coordinated with distorted mono-capped square antiprismatic geometry. An elaborate hydrogen bonding system holds the parallel polymeric chains together.     

Mn and Cu–Na coordination compounds containing the tetrazole-5-acetato anion (tza) ligands

Two novel coordination compounds [Mn(tza) · (H₂O)₂]_n (1) and [CuNa₂(tza)₂ · (H₂O)₄]_n (2) (tza = tetrazole-5-acetato) were synthesized by reaction of tetrazole-5-ethyl acetate with Mn(ClO₄)₂ · 6H₂O and CuCl₂ · 2H₂O in sodium hydroxide solution, respectively. Compound 1 has a one-dimensional (1D) polymeric chain that are bridged by tza linker, while compound 2 has two crystallographically independent metal centers (Cu and Na), that are bridged by tza into a 2D layer structure. The magnetic susceptibility study of 1 demonstrates the presence of antiferromagnetic interaction between two adjacent Mn(II) ions.     

[H3NNH3]2K2MnMo9O32·(NH3)·3H2O: synthesis and crystal structure determination of a novel heteropolyoxometallate related to the Waugh structure

A novel heteropolyoxometallate with the formula [H₃NNH₃]₂K₂MnMo₉O₃₂·(NH₃)·3H₂O has been prepared in water solution. The crystal structure of the title compound was determined by the single-crystal method. This new mixed metal anionic complex crystallizes in the rhombohedral space group R3 (No. 146) with a=b=15.873(5), c=12.344(6) Å, γ=120°. The disordered structure contains three molecules in the unit cell. Full-matrix least-squares refinements of the title complex yielded final reliability (R) factors of 0.0356 (Rw=0.0868) with a goodness-of-fit (GOF, Σ₂) value of 1.099 based on 1430 [I>2σ(I)] observed reflections. All Mo and Mn atoms are six-coordinated octahedrally to form a Mn-centered cage with a Mo₉O₃₂ group as the framework.     

Solvothermal synthesis of a novel mixed valence Cu(I)/Cu(II) complex containing sulphate, malate and 4,4-bipyridine, [CuCu2(mal)(SO4)(bpy)2 · H2O]n. Unique binding mode of the malate anion

The reaction of CuSO₄ · 5H₂O with 4,4^′-bipyridine and malic acid at 140 °C under solvothermal conditions afforded a mixed valence three-dimensional coordination polymer [Cu^ICu^II₂(mal)(SO₄)(bpy)₂ · H₂O]_n, (1). The building unit consists of a Cu²⁺-dimer in which copper centers are bridged by malate and sulphate anions. SO₄²⁻ anion further connects dimeric unit with the Cu¹⁺ center. Building units are linked by 4,4^′-bipyridine ligands to form double chains, that are interconnected into 3D network through additional sulphate bridge.     

Synthesis and crystal structures of two new inorganic–organic hybrid polyoxomolybdate complexes: [Himi]4[{Co(imi)2(H2O)2}Mo7O24] · 4H2O and [Zn(imi)4]2[(imi)2Mo8O26] · 6H2O

The two new inorganic–organic hybrid polyoxomolybdate complexes [Himi]₄[{Co(imi)₂(H₂O)₂}Mo₇O₂₄] · 4H₂O (1) and [Zn(imi)₄]₂[(imi)₂Mo₈O₂₆] · 6H₂O (2) (imi = imidazole) have been prepared by conventional aqueous solution synthesis. Compound 1 consists of heptamolybdate anions [Mo₇O₂₄]⁶⁻ covalently linked by [CoN₂O₄]²⁺ octahedra into one-dimensional zigzag-shaped chains. The zigzag-shaped chains are further linked together via the hydrogen-bonding interactions to form a 2D supramolecular framework. Compound 2 is build up of an imidazole-coordinated octamolybdate anion, two imidazole coordinating zinc cations and lattice water molecules to form a three-dimensional framework via complex hydrogen-bonding.     

Catalytic properties of Ru-η-C6H6-diphosphine complexes for hydrogenation of benzene in aqueous-organic biphasic system

The influences of pH on the catalytic properties of Ru-η⁶-C₆H₆-diphosphine complex [RuCl(η⁶-C₆H₆)(BISBI)]Cl (1) (BISBI = 2,2′-bis(diphenylphosphinomethyl)-1,1′-biphenyl), [RuCl(η⁶-C₆H₆)(BDPX)]Cl (2) (BDPX = 1,2-bis(diphenylphosphinomethyl)benzene), Ru₂Cl₄(η⁶-C₆H₆)₂(μ₂-BDNA) (3) (BDNA = 1,8-bis(diphenylphosphinomethyl)naphthalene), [RuCl(η⁶-C₆H₆)(BISBI)]BF₄ (4), [RuCl(η⁶-C₆H₆)(BDPX)]BF₄ (5), and [(η⁶-C₆H₆)₂Ru₂Cl₂(μ₂-Cl)(μ₂-BDNA)]BF₄ (6) for the hydrogenation of benzene were investigated in aqueous-organic biphasic system. The hydrogenation of benzene catalyzed by all complexes yielded only cyclohexane. The catalytic results revealed that the stabilities of these complexes were not only closely relative with their compositions or molecular structures but also the pH value of aqueous solution. Complexes 1 and 2 were homogeneous catalysts at pH <5, but complexes 3, 4, 5 and 6 were partly decomposed in the same reaction conditions and played simultaneously the roles of homogeneous and heterogeneous catalysts. When the pH was up to 12, all of six complexes were gradually decomposed to Ru(0) particles. The addition of extra phosphine ligand was favorable to prevent these complexes from decomposing in the catalytic process. The experiment of mercury poisoning and the curve of conversion vs time strongly supported above conclusions.     

Syntheses, structures, and photoluminescence of two Cd(II) coordination polymers constructed from analogue (pyridyl)imidazole derivative and polycarboxylate acid

Two novel Cd(II) coordination frameworks based on a semirigid asymmetric ligand L and aromatic multi-carboxylate ligands, {[Cd₂L(btc)(H₂O)₂]·5H₂O}_n (1) and [Cd₂L₂(bdc)]_n (2) (L = (4-((2-(pyridine-2-yl)-1H-imidazol-1-yl)methyl)benzoic acid, H₃btc = 1,3,5-benzenetricarboxylic acid, H₂bdc = 1,3-benzenedicarboxylic acid), have been hydrothermally synthesized, and structurally characterized by elemental analysis, IR spectroscopy, single-crystal X-ray crystallography. Due to various coordination modes and conformations of the semirigid asymmetric ligand, and carboxylate containing co-ligands, therefore, the two complexes exhibit structural and dimensional diversity. Complex 1 exhibits a novel 2D (3, 5)-connected network structure with (3·5²)(3²·5³·6⁴·7) topology. Complex 2 exhibits a novel 3D CdSO₄ topology, which is formed from different dinuclear cadmium units. In addition, the photoluminescence properties of the free ligand L, and complexes 1 and 2 were studied in the solid state at room temperature.     

Hydrothermal synthesis and crystal structure of a new copper(II) molybdenum(VI) arsenate(III), (C5H5NH)2(H3O)2[(CuO6)Mo6O18(As3O3)2]

A new copper(II) molybdenum(VI) arsenate(III), (C₅H₅NH)₂(H₃O)₂[(CuO₆)Mo₆O₁₈(As₃O₃)₂], has been hydrothermally synthesized and characterized by single crystal X-ray diffraction and TG analysis. The compound crystallizes in the monoclinic space group P2₁/n with a=9.303(2), b=20.731(4), c=12.617(3) Å, β=104.17(3)°, V=2359.3(8) ų, Z=2 and R1(wR2)=0.0296(0.0683). The structure is composed of pyridinium cations, proton hydrates and [(CuO₆)Mo₆O₁₈(As₃O₃)₂]⁴⁻ polyanions. The polyanion framework derives from the Anderson type; the central octahedron is filled up by copper(II) and is capped on both sides by a cyclic As₃O₆ group.     

A CdSO4-like 3-D framework constructed from monosodium substituted Keggin arsenotungstates and copper(II)-ethylenediamine complexes

A 6⁵·8 CdSO₄-like 3-D framework [Cu(en)₂]₃[α-AsW₁₁NaO₃₉]·2H₂O (1) constructed by monosodium-substituted Keggin arsenotungstates and copper(II)-ethylenediamine complexes (en = ethylenediamine) has been synthesized by reaction of Na₈[α-HAsW₉O₃₄]·11H₂O, CuCl₂·2H₂O and ethylenediamine under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis and single-crystal X-ray diffraction. Crystal data for 1: C₁₂H₅₂AsCu₃N₁₂NaO₄₁W₁₁, monoclinic, Cc, a = 20.409(9) Å, b = 16.737(8) Å, c = 16.561(7) Å, β = 104.607(7)°, V = 5474(4) Å³, T = 296(2) K; Z = 4, μ = 24.860 mm⁻¹, GOOF = 1.086, R₁ = 0.0284, wR₂ = 0.0759. To the best of our knowledge, 1 represents the first 6⁵·8 CdSO₄-like 3-D monovacant Keggin arsenotungstate derivative in polyoxometalate chemistry.