Two Heterometallic–Organic Frameworks Composed of Iron(III)‐Salen‐Based Ligands and d10 Metals: Gas Sorption and Visible‐Light Photocatalytic Degradation of 2‐Chlorophenol

Two examples of heterometallic–organic frameworks (HMOFs) composed of dicarboxyl‐functionalized Fe^III‐salen complexes and d¹⁰ metals (Zn, Cd), [Zn₂(Fe‐L)₂(μ₂‐O)(H₂O)₂] ? 4 DMF ? 4 H₂O ( 1 ) and [Cd₂(Fe‐L)₂(μ₂‐O)(H₂O)₂] ? 2 DMF ? H₂O ( 2 ) (H₄L=1,2‐cyclohexanediamino‐N,N′‐bis(3‐methyl‐5‐carboxysalicylidene), have been synthesized and structurally characterized. In 1 and 2 , each square‐pyramidal Fe^III atom is embedded in the [N₂O₂] pocket of an L^4? anion, and these units are further bridged by a μ₂‐O anion to give an (Fe‐L)₂(μ₂‐O) dimer. The two carboxylate groups of each L^4? anion bridge Zn^II or Cd^II atoms to afford a 3D porous HMOF. The gas sorption and magnetic properties of 1 and 2 have been studied. Remarkably, 1 and 2 show activity for the photocatalytic degradation of 2‐chlorophenol (2‐CP) under visible‐light irradiation, which, to the best of our knowledge, is the first time that this has been observed for Fe^III‐salen‐based HMOFs.     

Visible‐Light‐Induced Water Oxidation Mediated by a Mononuclear‐Cobalt(II)‐Substituted Silicotungstate

A mononuclear‐cobalt(II)‐substituted silicotungstate, K₁₀[Co(H₂O)₂(γ‐SiW₁₀O₃₅)₂] ? 23 H₂O (POM‐ 1 ), has been evaluated as a light‐driven water‐oxidation catalyst. With in situ photogenerated [Ru(bpy)₃]³⁺ (bpy=2,2′‐bipyridine) as the oxidant, quite high catalytic turnover number (TON; 313), turnover frequency (TOF; 3.2 s^?1), and quantum yield (Φ_QY; 27 %) for oxygen evolution at pH 9.0 were acquired. Comparison experiments with its structural analogues, namely [Ni(H₂O)₂(γ‐SiW₁₀O₃₅)₂]^10? (POM‐ 2 ) and [Mn(H₂O)₂(γ‐SiW₁₀O₃₅)₂]^10? (POM‐ 3 ), gave the conclusion that the cobalt center in POM‐ 1 is the active site. The hydrolytic stability of the title polyoxometalate (POM) was confirmed by extensive experiments, including UV/Vis spectroscopy, linear sweep voltammetry (LSV), and cathodic adsorption stripping analysis (CASA). As the [Ru(bpy)₃]²⁺/visible light/sodium persulfate system was introduced, a POM–photosensitizer complex formed within minutes before visible‐light irradiation. It was demonstrated that this complex functioned as the active species, which remained intact after the oxygen‐evolution reaction. Multiple experimental parameters were investigated and the catalytic activity was also compared with the well‐studied POM‐based water‐oxidation catalysts (i.e., [Co₄(H₂O)₂(α‐PW₉O₃₄)₂]^10? (Co₄‐POM) and [Co^IIICo^II(H₂O)W₁₁O₃₉]^7? (Co₂‐POM)) under optimum conditions.     

Kalium-μ-dithio-bis(pentacyanokobaltat(III)) und Kalium-μ-diseleno-bis(pentacyanokobaltat(III))

Potassium-μ-dithio-bis(pentacyanocobaltate(III)) and Potassium-μ-diseleno-bis(pentacyanocobaltate(III)) The oxidation of [Co(CN)₅]^3? by sulfur or selenium leads to the complexes [Co₂S₂(CN)₁₀]^6? and [Co₂Se₂(CN)₁₀]^6?, respectively, which have been isolated as potassium salts K₆[Co₂S₂(CN)₁₀] · 4 H₂O and K₆[Co₂Se₂(CN)₁₀] · 5 H₂O. The μ-dithio complex has also been formed from [Co(CN)₅]^3? with polysulfide, from [CoOH(CN)₅]^3? with H₂S + O₂ and from [Co₂O₂(CN)₁₀]^6? with H₂S. As shown by their vibrational spectra the new complexes contain bridges Co? S? S? Co and Co? Se? Se? Co, respectively.     

Windmill Co4{Co4(μ4‐O)} with 16 Divergent Branches Forming a Family of Metal–Organic Frameworks: Organic Metrics Control Topology,Gas Sorption,and Magnetism

A series of highly connected metal–organic frameworks (MOFs), [Co₈(O)(OH)₄(H₂O)₄(ina)₈](NO₃)₂ ? 2 C₂H₅OH ? 4 H₂O ( 1 ), [Co₈(O)(OH)₄(H₂O)₄(pba)₈](NO₃)₂ ? 8 C₂H₅OH ? 28 H₂O ( 2 ), and [Co₈(O)(OH)₄(H₂O)₄(pbba)₈](NO₃)₂ ? guest ( 3 ), in which ina=isonicotinate, pba=4‐pyridylbenzoate, and pbba=4‐(pyridine‐4‐yl)phenylbenzoate, is reported. These MOFs contain a new secondary building unit (SBU), with a square Co₄(μ₄‐O) central unit having the rare μ₄‐O^2? motif, which is decorated by the other four peripheral cobalt atoms through μ₃‐OH in a windmill‐like shape. This SBU holds 16 divergent connecting organic ligands, pyridyl‐carboxylates, to form three different frameworks. The high porosity of desolvated 2 is shown by the efficient gas absorption of N₂, CO₂, CH₄, and H₂. In addition, 1 and 2 exhibit unusual canted antiferromagnetic behavior with spin‐glass‐like relaxation, with blocking temperatures that are fairly high, 20 K ( 1 ) and 10 K ( 2 ), for cobalt materials. The relationship between the metal clusters and linkers has been studied, in which the size and rotational degrees of freedom of the ligands are found to control the topology, gas sorption, and magnetic properties.     

Ab Initio Calculations of Hydroxoplatinum Compounds: II. Binuclear Platinum(IV) Superoxo Complexes

The structural and spectral data have been obtained by ab initio methods for the [(OH)₄Pt(μ-O₂)(μ- OH)Pt(OH)₄]^2?, [(OH)₄Pt(μ-O₂)(μ-OH)Pt(OH)₄(OH)]^3?, [(OH)₅Pt(μ-O₂)Pt(OH)₅]^3?, and [(H₂O)(OH)₄Pt(μ- O₂)Pt(OH)₄(H₂O)]- clusters, corresponding to binuclear platinum(IV) superoxo complexes with one and two bridges. The data obtained are in good agreement with experimental data and make it possible to judge the structure of available complexes.     

Transition metal hydrides : (Advances in Chemistry Series No. 167), R. Bau,ed., American Chemical Society,Washington, D.C., 1978, ix + 429 pages, $ 42.00

The transition metal cluster hydride complex H₂Os₃(CO)₁₀ reacts with aryl isocyanates and isothiocyanates to yield products containing N-aryl-formamido and -thioformamido ligands. The compound (μ-p-CH₃C₆H₄NC(H)O) (μ-H)Os₃(CO)₁₀ has been analyzed by x-ray crystallographic methods and is shown to contain a formamido ligand bridging the edge of the triosmium cluster.     

pH-dependent assembly of saturated to dilacunary Keggin-based silicotungstate: [Cu(en)2(H2O)][H2en]{γ-SiW10O36[Cu(en)2(H2O)]2}·7.5H2O

By controlling the pH of the reaction system, a dilacunary γ-Keggin silicotungstate [Cu(en)₂(H₂O)][H₂en]{γ-SiW₁₀O₃₆[Cu(en)₂(H₂O)]₂}·7.5H₂O (1) (en?=?ethylenediamine) has been hydrothermally synthesized by the reaction of CuCl₂ with α-H₄SiW₁₂O₄₀ and characterized by IR spectra, thermogravimetric analysis, and single-crystal X-ray diffraction. The product is prepared in the pH range 7.9–8.2, which reveals that pH plays a key role in the assembly of saturated α-H₄SiW₁₂O₄₀ to dilacunary [γ-SiW₁₀O₃₆]^8? polyoxometalate. The polyoxoanion {γ-SiW₁₀O₃₆[Cu(en)₂(H₂O)]₂]}^4? of 1 presents a rare [γ-SiW₁₀O₃₆]^8?-retaining structure, in which two lacunary sites of [γ-SiW₁₀O₃₆]^8? are unoccupied, meanwhile, two [Cu(en)₂(H₂O)]²⁺ groups are grafted on either side of the [γ-SiW₁₀O₃₆]^8? unit by Cu–O–W bond.     

Hydrothermal Combination of Trilacunary Dawson Phosphotungstates and Hexanickel Clusters: From an Isolated Cluster to a 3D Framework

Three novel hexa‐Ni‐substituted Dawson phosphortungstates [Ni₆(en)₃(H₂O)₆(μ₃‐OH)₃(H₃P₂W₁₅O₅₆)] ? 14 H₂O ( 1 ), [Ni(enMe)₂(H₂O)][Ni₆(enMe)₃(μ₃‐OH)₃(H₂O)₆(HP₂W₁₅O₅₆)] ? 10 H₂O ( 2 ), and [Ni(enMe)₂]₃[Ni(enMe)₂(H₂O)][Ni(enMe)(H₂O)₂][Ni₆(enMe)₃(μ₃‐OH)₃(Ac)₂(H₂O)(P₂W₁₅O₅₆)]₂ ? 6 H₂O ( 3 ) (en=ethylenediamine, enMe=1, 2‐diaminopropane, Ac=CH₃COO^?) have been made under hydrothermal conditions and were characterized by IR spectroscopy, elemental analysis, diffuse reflectance spectroscopy, thermogravimetric analysis, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. The common structural features of compounds 1 – 3 contain the similar hexa‐Ni‐substituted Dawson polyoxometalate (POM) units that can be viewed as a [Ni₆(μ₃‐OH)₃]⁹⁺ cluster capping on a [P₂W₁₅O₅₆]^12? fragment. Compounds 1 and 2 are two isolated clusters, whereas compound 3 is the first 3D POM framework constructed from hexa‐Ni‐substituted Dawson POM units and Ni(enMe) complex bridges. The preparations of compounds 1 – 3 not only indicate that triangle coplanar Ni₆ clusters are very stable fragments in both trivacant Keggin and trivacant Dawson POM systems, but also offer that the hydrothermal technique can act as an effective strategy for making novel Dawson‐type high‐nuclear transition‐metal cluster substituted POMs by combination of lacunary Dawson precusors with transition‐metal cations in the tunable role of organic ligands. In addition, magnetic measurements illustrate that there exist overall ferromagnetic interactions in compound 3 .     

High-nuclearity Ni-substituted polyoxometalates: a series of poly(polyoxotungstate)s containing 20–22 nickel centers

Three high‐nuclearity Ni‐substituted polyoxotungstates (POTs)—[Ni(enMe)₂(H₂O)₂]₂[Ni(H₂O)₆]₂‐ [Ni(enMe)₂][Ni(H₂O)₂]_1.5[HNi₂₀X₄W₃₄‐ (OH)₄O₁₃₆(H₂O)₆(enMe)₈] ? 11 H₂O ( 3 ), [Ni(en)₂(H₂O)]₂[H₈Ni₂₁X₄W₃₄(OH)₄‐ O₁₃₆(en)₁₀(H₂O)₅] ? 22 H₂O ( 4 ), and [Ni‐(enMe)₂]₂[H₆Ni₂₂X₄W₃₄(OH)₄O₁₃₆(H₂O)₆(enMe)₁₀] ? 18 H₂O ( 5 ), in which en=ethylenediamine, enMe=1,2‐diaminopropane, X=0.5 P+0.5 Ge—were made under hydrothermal conditions and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, powder X‐ray diffraction, and single‐crystal X‐ray diffraction. The structures of 3 – 5 can be viewed as novel derivatives of [H₆Ni₂₀P₄W₃₄(OH)₄O₁₃₆(enMe)₈‐ (H₂O)₆] ? 12 H ₂O ( 1 ) and [Ni(en)₂‐ (H₂O)]₂[H₈Ni₂₀P₄W₃₄(OH)₄O₁₃₆(en)₉‐ (H₂O)₄] ? 16 H ₂O ( 2 ), which both contain 20 nickel ions per structural unit. Compound 3 is the first example of a 1D cluster chain constructed from Ni₂₀‐substituted polyanions [HNi₂₀X₄‐ W₃₄(OH)₄O₁₃₆(H₂O)₆(enMe)₈]^11? and [Ni(enMe)₂]²⁺ bridges. Compound 4 is a novel cluster–organic chain built by Ni₂₁‐substituted polyanions [H₈Ni₂₁X₄W₃₄(OH)₄O₁₃₆(en)₁₀(H₂O)₅]^4? and en molecule bridges. Compound 5 is a discrete POT with 22 Ni centers, and is not only the largest nickel‐substituted POT, but also contains the highest number of nickel ions in one polyanion to date. Magnetic measurements illustrate that overall ferromagnetic interactions exist in 1 – 5 . The magnetic behavior of 1 and 2 was theoretically simulated by the MAGPACK magnetic program package.     

Self-assembly of 1-D, 2-D,and 3-D transition-metal coordination polymers based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide

Three coordination polymers, {[Co(C₁₀H₅N₃O₅)(H₂O)₂]·H₂O}_n (1), {[Mn₃(C₁₀H₅N₃O₅)₂Cl₂(H₂O)₆]·2H₂O}_n (2), and {[Cu₃(C₁₀H₄N₃O₅)₂(H₂O)₃]·4H₂O}_n (3), based on a T-shaped tripodal ligand 4-(4,5-dicarboxy-1H-imidazol-2-yl)pyridine 1-oxide (H₃DCImPyO), were synthesized under hydrothermal conditions. The polymers showed diverse coordination modes, being characterized by elemental analysis, infrared spectroscopy, and single-crystal X-ray structure analysis. In 1, the HDCImPyO^2? generated a 1-D chain by adopting a μ₂-kN, O : kN′, O′ coordination mode to bridge two Co(II) ions in two bis-N,O-chelating modes. In 2, the HDCImPyO^2? adopted a μ₃-kN, O : kO′, O′′ : O′′′ coordination mode to bridge two crystallographically independent Mn(II) ions, forming a 2-D hcb network with {6³} topology. In 3, by adopting μ₄-kN, O : kO′, O′′ : kN′′, O′′′ : O′′′′ coordination, DCImPyO^3? bridged three crystallographically independent Cu(II) ions to form a 3-D framework having the stb topology.     

Three new ZnII coordination polymers constructed from a semi‐rigid tricarboxylic acid: structural changes caused by flexibility and luminescence sensing for hexavalent chromate anions

Coordination polymers (CPs) with specific structures and functional luminescence have been widely designed as sensors for detecting small molecules and ions. In this study, with or without the help of an N‐donor auxiliary linker, three new Zn^II CPs, namely, three‐dimensional (3D) poly[[pentaaquabis[μ₃‐5‐(4‐carboxybenzyloxy)isophthalato]bis[μ₆‐5‐(4‐carboxylatobenzyloxy)isophthalato]di‐μ₃‐hydroxido‐hexazinc(II)] trihydrate], {[Zn₆(C₁₆H₁₀O₇)₂(C₁₆H₉O₇)₂(OH)₂(H₂O)₅]·3H₂O}_n or {[Zn₆(μ₃‐HL)₂(μ₆‐L)₂(μ₃‐OH)₂(H₂O)₅]·3H₂O}_n, ( I ), one‐dimensional (1D) catena‐poly[[[aqua(1,10‐phenanthroline)zinc(II)]‐μ₂‐5‐(4‐carboxybenzyloxy)isophthalato] dihydrate], {[Zn(C₁₆H₁₀O₇)(C₁₂H₈N₂)(H₂O)]·2H₂O}_n or {[Zn(μ₂‐HL)(phen)(H₂O)]·2H₂O}_n (phen is 1,10‐phenanthroline), ( II ), and 3D poly[diaquatetrakis(4,4′‐bipyridine)bis[μ₆‐5‐(4‐carboxylatobenzyloxy)isophthalato]di‐μ₃‐formato‐di‐μ₃‐hydroxido‐pentazinc(II)], [Zn₅(C₁₆H₉O₇)₂(HCOO)₂(OH)₂(C₁₀H₈N₂)₄(H₂O)₂]_n or [Zn₅(μ₄‐L)₂(bpy)₄(μ₂‐OH)₂(μ₃‐HCOO)₂(H₂O)₂]_n (bpy is 4,4′‐bipyridine), ( III ), have been constructed from the semi‐rigid tricarboxylic acid 5‐(4‐carboxybenzyloxy)isophthalic acid (H₃L) under hydrothermal conditions. CP ( I ) exhibits a twofold interpenetrated 3D+3D→3D skeleton with a 3 , 5 ‐conn topology constructed from triangular trinuclear [Zn₃(COO)₄(μ₃‐OH)] clusters, in which the H₃L ligand adopts three different coordination modes. CP ( II ) exhibits a 1D infinite chain and stacking that gives a 3D structure mediated by hydrogen bonds and weak interactions. CP ( III ) is an interesting 3D 3 , 4 , 8 ‐conn network including linear tetranuclear [Zn₄(μ₂‐OH)₂(HCOO)₂(COO)₂] clusters with a new {4·6²}₂{4·6⁴·8}{4⁶·6¹⁹·8³} topological symbol. The influences of the flexible –CH₂–O– linker of the H₃L ligand and subtle environmental factors, such as solvent, pH value and auxiliary ligands, on the formation of the final structures are also discussed. The solid‐state fluorescence spectra of CPs ( I )–( III ) were recorded at room temperature and all show better fluorescence performances than H₃L. In particular, ( II ) can act as a potential multifunctional fluorescent material for sensing hexavalent chromium ions in aqueous solution with high stability, selectivity and sensitivity. Under ultraviolet light of 365 nm from a UV lamp, a signal response of fluorescence from turning on to off can be observed with the naked eye. It was found that the detection for hexavalent chromium (i.e. Cr₂O₇^2?) by ( II ) has a high selectivity [K_SV = 1.61 × 10⁴M^?1 and limit of detection (LOD) = 0.434 µM] in aqueous solution. Quenching mechanisms were also studied in detail.     

Magnetothermal studies of a series of coordination clusters built from ferromagnetically coupled {Mn(II) (4)Mn(III) (6)} supertetrahedral units

Three high‐nuclearity mixed valence manganese^II/III coordination clusters, have been synthesised, that is, [Mn ^III ₆Mn ^II ₄(μ₃‐O)₄(HL¹)₆(μ₃‐N₃)₃(μ₃‐Br)(Br)](N₃)_0.7/(Br)_0.3 ? 3 MeCN ? 2 MeOH ( 1 ) (H₃L¹=3‐methylpentan‐1,3,5‐triol), [Mn^III₁₁Mn^II₆(μ₄‐O)₈(μ₃‐Cl)₄(μ,μ₃‐O₂CMe)₂(μ,μ‐L²)₁₀Cl_2.34(O₂CMe)_0.66(py)₃(MeCN)₂] ? 7 MeCN ( 2 ) (H₂L²=2,2‐dimethyl‐1,3‐propanediol and py is pyridine), and [Mn^III₁₂Mn^II₇(μ₄‐O)₈(μ₃‐η¹N₃)₈(HL³)₁₂(MeCN)₆]Cl₂ ? 10 MeOH ? MeCN ( 3 ) (H₃L³=2,6‐bis(hydroxymethyl)‐4‐methylphenol) with high ground‐spin states, S=22, 28±1, and 83/2, respectively; their magnetothermal properties have been studied. The three compounds are based on a common supertetrahedral building block as seen in the Mn₁₀ cluster. This fundamental magnetic unit is made up of a tetrahedron of Mn^II ions with six Mn^III ions placed midway along each edge giving an inscribed octahedron. Thus, the fundamental building unit as represented by compound 1 can be described as a Mn₁₀ supertetrahedron. Compounds 2 and 3 correspond to two such units joined by a common edge or vertex, respectively, resulting in Mn₁₇ and Mn₁₉ coordination clusters. Magnetothermal studies reveal that all three compounds show interesting long‐range magnetic ordering at low temperature, originating from negligible magnetic anisotropy of the compounds; compound 2 shows the largest magnetocaloric effect among the three compounds. This is as expected and can be attributed to the presence of a small magnetic anisotropy, and low‐lying excited states in compound 2 .     

Dinuclear cobalt and manganese squarate complexes with bidentate N-donor ligand: syntheses, crystal structures, spectroscopic, thermal and voltammetric studies

The crystal structures of [M₂(phen)₄(H₂O)₂(C₄O₄)]· C₄O₄· 8H₂O [M = Co²⁺ (1), Mn²⁺ (2); phen: 1,10-phenanthroline] complexes have been prepared and characterized by IR spectroscopy, thermal analysis and single X-ray diffraction techniques. Their structures consist of [Co₂(phen)₄(H₂O)₂(C₄O₄)]²⁺ (1) and [Mn₂(phen)₄(H₂O)₂(C₄O₄)]²⁺ (2) dinuclear cobalt(II) and manganese(II) cations, uncoordinated C₄O ₄ ^2? (SQ^2?) dianion and crystalization water molecules. In both complexes the metal ions have distorted octahedral geometry. The squarate adopts the μ-1,3 (1) and (2) bis(monodentate) coordination modes, the intradimer M–M separation being 8.053(7) Å (1) and 8.175(4) Å (2), respectively, while the other squarate acts as a counter anion. The voltammetric behaviour of complexes (1) and (2) was investigated in DMSO (dimethylsulfoxide) solution by cyclic voltammetry using n-Bu₄NClO₄ as supporting electrolyte. The complexes exhibit both metal and ligand centred electroactivity in the potential ?±1.75 V versus Ag/AgCl reference electrode. The dianion SQ^2? is oxidized in two consecutive steps to the corresponding radical monoanion and neutral form.     

Syntheses and structures of two new lithium-heptamolybdates

The synthesis, crystal structures, IR, UV–vis, ⁷Li NMR spectra, electrochemical investigations, and conductivity studies of two new lithium-heptamolybdates, (NH₄)₄[Li₂(H₂O)₇][Mo₇O₂₄]·H₂O (1) and (NH₄)₃[Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]·2H₂O (2), are reported. In 1 the (NH₄)⁺ and [Li₂(H₂O)₇]²⁺, cations are charge balanced by the heptamolybdate anion. In 2, the [Mo₇O₂₄]^6? anion is coordinated to three unique Li⁺ ions via a μ₆-hexadentate-binding mode resulting in the formation of a two-dimensional (2-D) [Li₃(H₂O)₄(μ₆-Mo₇O₂₄)]^3? anionic complex, charge neutralized by three (NH₄)⁺ ions. The cations, anions, and the lattice water molecules in 1 and 2 are linked by weak H-bonding interactions.     

[Mo4O4(μ-S)4(μ-OH)2(μ-H2O)(H2O)2(pba)]2−: An Original Coordination Mode for the Ligand 1,3-Propylenebis(Oxamate)

The novel polyoxothioanion [Mo₄S₄O₄(OH)₂(OH₂)₃pba]^2? where pba^4? ligand is the 1,3-propylenebis(oxamate), was prepared by reacting Mo₁₂S₁₂O₁₂(OH)₁₂(OH₂)₆ ring with [Cu-pba]^2? in aqueous medium. NaK[Mo₄O₄(μ-S)₄(μ-OH)₂(μ-H₂O)(H₂O)₂(pba)] ·7H₂O was isolated in the solid state and fully characterized by X-ray diffraction study (tetragonal, P4(2)/m [a=20.4962(4) Å; b=20.4962(4) Å; c=14.7013(5) Å). The molecular structure consists of an arc cycle shape tetranuclear enchainment {Mo₄S₄O₄(OH)₂ (OH₂)₃} closed by a pba^4? ligand. The 3-D packing, resulting from the connection between K⁺ and Na⁺ and the coordination complex {Mo₄-pba]^2? is described. The ¹H-NMR characterization of the complex in aqueous solution is given. The ¹H-NMR spectrum exhibits four signals assigned to four enantiotopic protons of the alkyl chain of the pba^4? ligand and is in agreement with crystal structure of the complex [Mo₄-pba]^2?. The compound was also characterized by infrared spectroscopy.     

A new POM-templated metal–organic complex based on the flexible bis-pyridyl-bis-amide ligand

A new POM-templated metal?Corganic complex [Cu₄(L)₇(H₂O)₁₂(SiMo₁₂O₄₀)₂]·7H₂O [L?=?N,N??-bis(3-pyridinecarboxamide)-1,6-hexane], has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The results reveal that the complex is a 2D metal?Corganic coordination framework of [Cu₄(L)₇(H₂O)₁₂] _n ⁸ⁿ⁺ cations containing decanuclear cycles with dimensions of ca. 17.55?×?57.42 ?, in which the SiMo₁₂O₄₀ ^4? anions act as non-coordinated anionic templates. The electrochemical properties of a bulk-modified carbon paste electrode of the complex have been investigated, and the results indicate that the complex-modified CPE has good electrocatalytic activity toward the reduction of nitrite in aqueous 1?M H₂SO₄ solution.     

Temperature-Dependent Organic Functionalization of {Ni6PW9} Species: from Isolated Clusters to 1D Chain

Four new hexa-nickel(II)-substituted Keggin-type tungstophosphates [Ni₆(μ₃-OH)₃(oeen)₃(H₂O)₃(B-α-PW₉O₃₄)]·6H₂O (1, oeen = N-(2-hydroxyethyl)enediamine), [Ni₆(μ₃-OH)₃(oeen)₃(H₂O)₄(B-α-PW₉O₃₄)]₂·13H₂O (2), [Ni₆(μ₃-OH)₃(oeen)₂(tran)(H₂O)₃(B-α-PW₉O₃₄)]·3H₂O (3, tran = 1,4,7-triazonane) and [Ni₆(μ₃-OH)₃(oeen)₂(tran)(H₂O)₂(B-α-PW₉O₃₄)]·6H₂O (4) have hydrothermally made by controlling their reaction temperatures. 1–4 have been characterized by elemental analyses, IR spectra, powder X-ray diffraction, thermogravimetric analyses and single-crystal X-ray diffraction, respectively. Structural analyses reveal that they consist of {Ni₆(μ₃-OH)₃(H₂O) _n }⁹⁺ cores and B-α-PW₉O₃₄ (PW₉) units, and further are stabilized by organic neutral oeen/tran molecules. 1–3 are isolated clusters while 4 is the 1D chain structure. It should be noted that the tran molecules in 3 and 4 are derived from the oeen molecules in the starting materials.     

Zur Kenntnis von Kaliumarseniten im Dreistoffsystem K2O?As2O3?H2O. Darstellung und Kristallstruktur von K3(HAs2O4)(As2O4) · 3/2 H2O

Concerning Potassium Arsenites in the Three-Component System K₂O? As₂O₃? H₂O. Preparation and Crystal Structure of K₃(HAs₂O₄) (As₂O₄) · 3/2 H₂O The phase K₃(HAs₂O₄)(As₂O₄) · 3/2 H₂O has been identified in the system K₂O? As₂O₃? H₂O at 40°C and characterized by X-ray structural analysis. In the crystal lattice independent polymetaarsenite anions, [HAs₂O₄^?]_n and [As₂O₄^2?]_n, adopt parallel zweier single chains.     

{[Mn2(μ3‐Tda)2(μ‐H2O)(H2O)2(bipy)]·DMF}n – a 2D Manganese(II) Coordination Polymer involving Six‐membered Binuclear Metallacycle Nodes

The single crystal X‐ray analysis of a novel thiophene‐2,5‐dicarboxylic acid (H₂Tda) Manganese(II) coordination polymer, {Mn₂(μ₃‐Tda)₂(μ‐H₂O)(H₂O)₂(bipy)]·DMF}_n, shows two different types of Mn²⁺‐ions with environment of Mn1O₆ and Mn2O₄N₂, and the complex is a two‐dimensional polymer as a result of bridging (Tda)^2? ligands and by connecting the carboxylate‐ and water‐bridged {Mn₂(μ‐Tda)₂(μ‐H₂O)} nodes.     

Hydrolytic cleavage of a DNA-model phosphodiester: a new inorganic–organic hybrid constructed from a Zn-cluster with a polyoxometalate

An inorganic–organic hybrid constructed from a Zn-cluster with a polyoxometalate {[Zn₃Na₂(μ-OH)₂(bpdo)₆(H₂O)₁₆][PW₁₂O₄₀]₂}·(bpdo)₃·C₂H₅OH·2H₂O (bpdo?=?4,4′-bis(pyridine-N-oxide)) (1) has been synthesized by hydrothermal reaction and characterized by elemental analyses, IR spectra, and single crystal X-ray diffraction. The structural analysis indicates that 1 is an S-like complex constructed by [Zn₃Na₂(μ-OH)₂(bpdo)₆(H₂O)₁₆]^6? with two PW₁₂O₄₀ ^3? with water occupying several coordination sites and have the potential to act as labile ligands, allowing for substrate and nucleophile binding. Kinetic experiments for hydrolytic cleavage of the DNA-model phosphodiester bis(p-nitropheny1)phosphate (BNPP) were followed spectrophotometrically for absorbance increase at 400?nm in 4-(2-hydroxyethyl)piperazine-1–propane sulfonic acid (EPPS) buffer solution due to the formation of p-nitrophenoxide with 1 at pH 4.0 and 50?°C. UV spectroscopy indicates cleavage of the phosphodiester bond proceeds with pseudo-first-order rate constant 6.7(±0.2)?×?10^?7?s^?1, giving an inorganic phosphate and p-nitrophenol as the final products of hydrolysis. The results demonstrate that 1 exhibits good catalytic activity and reusability for hydrolytic cleavage of BNPP.