Template synthesis and characterization of hexaaza macrocycles containing pyridine iron(II) complex nanoparticles dispersed within nanoreactors of zeolite-Y

Iron(II) complexes with 18- and 20-membered hexaaza macrocyclic ligands were entrapped in the nanoreactors of zeolite-Y by a two-step process in the liquid phase: (i) adsorption of [bis(diamine)iron(II)] (diamine = 1,2-diaminoethane, 1,3-diaminopropane, 1,2-diaminobenzene, 1,3-diaminobenzene); [Fe(N–N)₂]²⁺–NaY; in the nanoreactors of the zeolite, and (ii) template condensation of the iron(II) precursor complex with 2,6-diacetylpyridine.The mode of bonding and overall geometry of the complexes and new complex nanoparticles entrapped in the nanoreactor of zeolite-Y ([Fe([18 or 20]py₂N₄)]²⁺–NaY, [Fe(Bzo₂[18 or 20]py₂N₄)]²⁺–NaY) has been inferred through FT-IR, TGA, XRD, XPS spectroscopic techniques and elemental analysis as well as nitrogen adsorption.     

A novel 3D twofold interpenetrating microporous metal-organic framework containing 1D water tapes with cyclic pentamer units

The self-assembly of Cu²⁺ ions with malate and 1,3-bis(4-pyridyl)propane (bpp) affords a 3D coordination polymer {[Cu(Hmal)(bpp) · 6H₂O]}_n (1) (malic acid = H₃mal). The metal ions were interconnected by α- and β-carboxylate of malate produce infinite [Cu(C₄H₄O₅)]_n layers, which were further pillared by bridging ligand bpp molecules to form a 3D interpenetrating network. Of further interest, lattice water molecules form 1D infinite water tapes in 1D open cavities.     

Two octamolybdate-based hybrids functionalized by 1,3-bis[tris(hydroxymethyl)methylamino]propane ligand

Two octamolybdate-based organic–inorganic hybrids functionalized by 1,3-bis[tris(hydroxymethyl)methylamino]propane (H₆bthmap) Na₂H₄[γ-Mo₈O₂₆(H₅bthmap)₂]·2H₂O (1) and [NH₄]₆{[Cu(H₃bthmap)]₂(β-Mo₈O₂₆)} (2) have been synthesized through the aqueous synthetic method and structurally characterized by elemental analyses, IR spectra, UV spectra, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. X-ray crystallography reveals that 1 consists of a classic [γ-Mo₈O₂₆]^4 − polyoxoanion decorated by two flexible [H₅bthmap]⁻ ligands through two O atoms from two [H₅bthmap]⁻ ligands and 2 contains a [β-Mo₈O₂₆]^4 − polyoxoanion with bisupporting [Cu(H₃bthmap)]⁻ anions via two terminal O atoms from the [β-Mo₈O₂₆]^4 − polyoxoanion. As far as we know, 1 and 2 represent the first octamolybdate-based hybrids with 1,3-bis[tris(hydroxymethyl)methylamino]propane ligands. The TG curves of 1 and 2 indicate two steps of weight loss and three steps of weight between 25 and 980 °C, respectively. Furthermore, the electrochemical and electrocatalytic properties of 1 and 2 have been investigated.     

Luminescent palladium(0) complexes bearing N-heterocyclic carbene and phosphine ligands

Palladium(0) complexes bearing a monodentate phosphine ligand and an N-heterocyclic carbene ligand have been prepared. In these complexes, photophysical properties of the complexes, [Pd(IPr)(PPh₃)] and [Pd(IPr)(P(o-tol)₃)] have been studied (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene). The emissive excited states have been tentatively assigned to ³MLCT. In addition to the results of the luminescent complexes, the synthesis of the related complexes, [Pd(O₂)(IPr)(P(m-tol)₃)] and [PdCl(CH₂Cl)(IPr)(P(MeOPh)₃)] (P(MeOPh)_3 = tris(pmethoxyphenyl)phosphine) have been studied and the structures were characterized by X-ray.     

Molybdenum-oxygen anionic chain grafted by Cu-phen complex. Synthesis,crystal structure and properties

An unreported inorganic-organic hybrid compound [Cu(phen)(H₂O)₂(Mo₃O₁₀)] (1) was hydrothermally synthesized and characterized with elemental analysis, IR spectroscopy, thermal analysis, luminescent spectroscopy, magnetic measurement. The crystal structure was determined with X-ray single-crystal diffraction. Compound 1 has a 1-D chain structure constructed by {Mo₃O₁₀}^2 − units via edge-sharing and [Cu(phen)(H₂O)₂]^2 + fragments grafting the chain from two sides via the coordination of the terminal oxygen atom of the MoO₆ octahedra to Cu^2 + ion. The coordination of phen to Cu^2 + ion increases the molecular rigidity so that an emission peak at 500 nm was observed and assigned to the phosphorescent n–π* and π–π* transition from ligand-centered triple state. In compound 1 Cu(II) exhibits an antiferromagnetic exchange.     

The CO methanation over NaY-zeolite supported Ni/Co3O4, Ni/ZrO2, Co3O4/ZrO2 and Ni/Co3O4/ZrO2 catalysts

The CO methanation was studied over zeolite NaY supported Ni, Co₃O₄, ZrO₂ catalysts. The XRD, N₂ physisorption and SEM analysis were used in order to characterize the catalysts. Catalytic activities were carried out under a feed composition of 1% CO, 50% H₂ and 49% He between the 125 °C to 375 °C. Except for the Ni/Co₃O₄/NaY catalyst, all catalysts gave high surface area because of the presence of zeolite NaY. Average pore diameter of the catalysts fell into the mesopore diameter range. The highest CO methanation activity was obtained with Ni/ZrO₂/NaY catalyst at which the CO methanation was started after 175 °C and 100% CO conversion was obtained at 275 °C using the same catalyst.     

Syntheses,structures and properties of two copper-2-picolinic-acid germanomolybdate hybrids with mixed organic components

Two inorganic–organic hybrids based on saturated α-Keggin-type germanomolybdates with mixed organic components [H₂DAP]₂[Cu(PA)₂][α-GeMo₁₂O₄₀]·8H₂O (1) and [NH₄]₂[H₈L] [Cu(PA)₂][α-GeMo₁₂O₄₀]·8H₂O (2) (DAP = 1.2-diaminopropane, HPA = 2-picolinic acid, H₆L = 1,3-bis[tris(hydroxymethyl)methylamino]propane) have been obtained via the conventional aqueous solution method and structurally characterized by elemental analysis, IR spectra, thermogravimetric (TG) analysis and single-crystal X-ray diffraction. 1 stands for an one-dimensional linear organic–inorganic hybrid germanomolybdate chain constructed from classical Keggin [α-GeMo₁₂O₄₀]^4 − units supported by [Cu(PA)₂] linkers, whereas 2 represents the first hybrid germanomolybdate containing the H₆L component and consists of a saturated α-Keggin polyanion [α-GeMo₁₂O₄₀]^4 −, a diprotonated [H₈L]^2 + cation, a copper coordination complex [Cu(PA)₂], two ammonium cations [NH₄]⁺ and eight lattice water molecules. Furthermore, the electrochemical and electrocatalytic properties of 1 and 2 have also been investigated in detail.     

An unique trinuclear triply bridged Cu(II) compound containing double acetato and single azido bridges: Synthesis,X-ray structure and magnetism of [Cu3(dpyam)2(μ1,1-N3)2(μ-CH3COO- κ-O1)2(μ-CH3COO-κ-O1,O2)2] · 2(H2O) (dpyam = di-2-pyridylamine)

The synthesis, characterization, crystal structure and magnetic properties of the unique azido-acetato bridged trinuclear triply bridged Cu(II) compound, [Cu₃(dpyam)₂(μ_1,1-N₃)₂(μ-CH₃COO-κ-O¹)₂(μ-CH₃COO-κ-O¹,O²)₂] · 2(H₂O), is reported. In the centrosymmetric compound, the central Cu atom is linked to two terminal Cu atoms by a double acetato bridge and an azido bridge, thereby providing a linear trinuclear unit. The coordination geometry around each of the terminal Cu(II) ions is distorted square pyramidal, while the geometry of the central Cu(II) ion is elongated octahedral. The magnetic susceptibility measurements, measured from 5 to 300 K revealed a weak antiferromagnetic interaction between the Cu(II) ions with a J value of −10.2 cm⁻¹. In the EPR no signals for the low-lying doublet are resolved at 77 K.     

Spectroscopic studies on bis(1-amidino-O-alkylurea) copper(II) sulfate complexes where alkyl = methyl,ethyl, n-propyl or n-butyl: EPR evidence for binuclear complexes

Four new Cu(II) Complexes viz. [Cu(II)(1-amidino-O-methylurea)₂]SO₄·2H₂O (1), [Cu(II)(1-amidino-O-ethylurea)₂](SO₄)₂·2H₂O (2), [Cu(II)(1-amidino-O-n-propylurea)₂] SO₄·2H₂O (3), [Cu(II)(1-amidino-O-n-butylurea)₂]₂(SO₄)₂·2H₂O (4) have been synthesized and characterized. EPR spectrum of complex 4 at RT consisted of fine-structure transitions (ΔMs = ±1) with zero-field splitting (ZFS) of 0.0485 cm^?1 and a half-field signal (ΔMs = ±2) at ca. 1600 G, revealed formation of binuclear complex (S = 1). Whereas EPR spectrum of complex 2 in DMSO showed a mixture of mononuclear and binuclear complex in the ratio 0.75:1.0 with ZFS of 0.0385 cm^?1. From the temperature dependence of the EPR signal intensity, the isotropic exchange-interaction constant J was evaluated.     

A three-dimensional zincic molybdenum (V) phosphate with helical channel: Synthesis,structure, and electrochemical properties

A new reduced zincic molybdophosphate, (H₂bpp)₃[Zn₃Mo₁₂^VO₂₄(OH)₆(H₂O)₂(HPO₄)₆(PO₄)₂]·2H₂O 1 (bpp = 1,3-bis(4-pyridyl)propane) has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the tetragonal space group I 41/a c d with a = 31.8033(4) Å, b = 31.8033(4) Å, c = 34.5593(8) Å, V = 34955.0(10) ų, and Z = 16 and exhibits a 4,6-connected 3-D framework with (3².8⁴)(3⁴.4².8³.9⁵.10) topology. The basic building blocks of [Zn(2)(Mo₆P₄)₂] are linked through [Zn(3)O₆] octahedra and [Zn(1)O₄] tetrahedra to construct 1-D chains along four different directions. Such 1-D chains are further connected by [Zn(1)O₄]²⁺ linkers to form a 3-D intricate framework with helical channels occupied by protonated bpp and water molecules. Additionally, the electrochemical property of the 1-CPE has been studied in detail.     

Zeolite-Y immobilized Metallo-ligand complexes: A novel heterogenous catalysts for selective oxidation

Transition metal [M = Co(II), Cu(II)] complexes of H₂L¹ and H₂L² ligands have been prepared as neat and nanohybrid zeolite-Y immobilized complexes. The various analytical tools such as FTIR, ICP-AES, elemental analysis, UV–vis, Brunauer, Emmett and Teller (BET) surface area analysis, Thermal analysis, scanning electron micrographs, Powder XRD, conductivity, magnetic moment, and AAS were employed for the characterization of the prepared catalysts. Among all catalysts, the [Cu(L¹)]-Y (heterogeneous) and [Cu(L¹)] (homogeneous) have offered high activity and selectivity over oxidation of cyclohexene. Moreover, the [Cu(L¹)] and [Cu(L¹)]-Y were employed as catalyst over various organic substrates at identical reaction condition. The immobilized catalyst [Cu(L¹)]-Y is found to be moderate active over oxidation of cyclohexane (75.2%,), benzene (8.21%), phenol (14.5%), styrene (87.5), benzyl alcohol (21.5%), limonene (11.2%), α-pinene (9.15%), and cyclooctane (76.8%) with high TON values (21942-2054). The mechanistic study using UV–vis and FTIR suggests the participation of active metalperoxo species, which is reinforced by its high catalytic activity over limonene (16.3%) in the absence oxidant.     

A new organic-inorganic hybrid based on dimeric [Mn2V22O64]10 − polyoxoanion as catalyst for oxidation of sulfides

A new organic-inorganic hybrid compound constructed from [Mn₂V₂₂O₆₄]^10 − units, H₆[(C₆H₄NO₂Cu(H₂O)₄)]₂[Mn₂V₂₂O₆₄]·28H₂O 1, has been synthesized and characterized by single-crystal X-ray diffraction, IR, powder X-ray diffraction (XPRD) and TG. Compound 1 is composed of dimeric [Mn₂V₂₂O₆₄]^10 − polyoxoanions, metal-organo fragments [(C₆H₄NO₂Cu(H₂O)₄)]^2 + and lattice water molecules. Moreover, a three-dimensional supramolecular structure is formed in 1 by the extensive hydrogen bond interaction among the terminal oxygen atoms of [Mn₂V₂₂O₆₄]^10 − anions, the coordinated waters of Cu^2 + ions and crystal water molecules. Compound 1 exhibits remarkable catalytic activity for the heterogeneous oxidation of sulfides under mild condition.     

A rare polyoxometalate based on mixed niobium-based polyoxoanions [GeNb18O54]14 − and [Nb3W3O19]5 −

Polyoxoniobate [GeNb₁₈O₅₄]^14 − and polyniobotungstate [Nb₃W₃O₁₉]^5 − are firstly found to co-crystallize at the same crystal to form a rare organic–inorganic hybrid polyoxometalate H[Cu(en)₂(H₂O)]₈[Cu(en)₂(H₂O)₂]₂{K₄[Cu(en)₂]₂[Cu(en)₂(GeNb₁₈O₅₄)]₂}[Nb₃W₃O₁₉]·32H₂O (1). Interestingly, in 1, the crescent-shaped polyoxoanions [GeNb₁₈O₅₄]^14 − can form dimeric secondary building units (SBUs) {[GeNb₁₈O₅₄]₂[K₂(H₂O)₅]₂} via the linkage of K⁺ cations. These dimeric SBUs can be further bridged by copper complexes to generate 1D infinite double strand chains with completely different isolated polyoxoanions [Nb₃W₃O₁₉]^5 − filling the gaps between chains.     

Structural diversity in coordination polymers with angular ditetrazole ligands

Three new coordination polymers with angular bis(1-tetrazol)diphenyl ligands as bridges, {[Ag(L¹)₂](NO₃) ? 2H₂O}_∞ [L¹ = 4,4'-bis(1-tetrazolyl)diphenyl methane], 1, [Ag(L²)₂(NO₃)]_∞ [L² = 4,4'-bis(1-tetrazolyl)diphenyl sulfone], 2, and [CuBr(L³)_0.5]_∞ [L³ = 4,4'-bis(1-tetrazolyl)diphenyl ether], 3, are reported, which show unique 2D structural types. Complex 1 forms 1D double-stranded helical chains where the cavities are threaded by linear hydrogen bondings formed by the co-crystallized water molecules and nitrate anions and complex 2 shows 2D grids involving M₄L₄ 64-membered metallocycles composed of helical chains, while complex 3 exhibits a 2D pleated net comprising 1D channels linked by the double-chain CuBr ribbons.     

A new copper(II) di-μ2-carboxylato bridged dinuclear complex: [Cu(oda)phen]2 · 6H2O (oda = oxydiacetate,phen = phenanthroline)

The oxydiacetate-bridged copper(II) complex [Cu(oda)(1,10-phen)] · 3H₂O (oda = oxydiacetate dianion, 1,10-phen = 1,10-phenanthroline) has been characterized. The complex is dinuclear and centrosymmetric with each copper atom residing in a CuN₂O₄ octahedral environment. The Cu(II) ions are bridged by two carboxylate-oxygen atoms in a strictly planar Cu₂O₂ core with a Cu–Cu distance of 3.417(2) Å. The magnetic susceptibility measurements (2–300 K) show weak ferromagnetic coupling between the copper ions with J = 3.3 cm⁻¹. The results are compared with those of the homologous [Cu(tda)(1,10-phen)]₂tda (tda = thiodiacetate dianion). A model proposed for the electronic structures of the complexes based on the density functional theory (DFT) satisfactorily accounts for the magnetic results.     

Tethered Pd-complex on solid support: Catalyst for acid-free carbonylation reactions

Palladium complex [Pd(pyca)(PPh₃)(OTs)] has been immobilized on solid matrices having ordered framework and high surface area as zeolite NaY (surface area ∼ 700 m² g⁻¹), using phosphotungstic acid [H₃PW₁₂O₄₀, xH₂O] as the molecular tether to form highly stable catalyst materials. The materials were thoroughly characterized using numerous techniques such as ³¹P CP-MAS NMR, XPS, powder XRD, SEM, etc. to confirm the immobilization and determine the state of the complex after tethering. Carbonylation of substituted olefins and alcohols was performed using this tethered catalyst without the addition of any free acid (protic/aprotic) promoter, with highly promising results. Thus, we can achieve dual advantages of efficient immobilization and partially promoter-free carbonylation catalysts, which is a substantial advancement in carbonylation catalysis.     

Synthesis,structural characterization and properties of a novel 1D helical chain arsenomolybdate {[Cu(en)2][Cu(en)(H2O)][(Cu(en)2(H2O)] [AsIIIAsVMo9O34)]} · 2H2O

An organic–inorganic hybrid 1D helical chain arsenomolybdate {[Cu(en)₂][Cu(en)(H₂O)][(Cu(en)₂(H₂O)] [As^IIIAs^VMo₉O₃₄)]} · 2H₂O (1) (en = ethylenediamine) has been hydrothermally synthesized and characterized by elemental analyses, IR, UV and CD spectrum, powder X-ray diffraction, TG-DTA and single-crystal X-ray diffraction. The asymmetric unit of 1 consists of a monocapped trivacant Keggin [As^IIIAs^VMo₉O₃₄]^6 − subunit, a pendant [Cu(en)₂(H₂O)]^2 + cation, a pendant [Cu(en)(H₂O)]^2 + cation, one bridging [Cu(en)₂]^2 + cation and two lattice water molecules. It should be noted that 1 illustrates a one-dimensional (1D) helical chain assembled by {[Cu(en)(H₂O)][(Cu(en)₂(H₂O)][As^IIIAs^VMo₉O₃₄)]}^2 − clusters and [Cu(en)₂]^2 + linkers.     

Trinuclear cobalt(II) sandwiched polyoxotungstobismuthate with antennal copper(II)-complex: A new method to combine hetero–transition–metallic ions

A new sandwich-type hybrid complex, Na₈{Cu(im)₄(H₂O)}[Cu(im)₄ {Na(H₂O)₂Co(im)}₃(BiW₉O₃₃)₂] · 11H₂O (1) (im = imidazole), has been synthesized and structurally characterized. The polyoxoanion in 1 contains trinuclear Co²⁺ ions in the central belt and an antennal Cu(II)–imidazole supported complex, which firstly represents a copper(II)-complex mono-supported tungstobismuthate system containing sandwiched trinuclear cobalt(II) ions. Neighboring polyanions further connect each other by disodium ions to yield a dimeric complex. The successful synthesis of 1 opens a new approach to the combination of different kinds of transition–metal ions by virtue of lacunary Keggin-type polyoxoanions, [BiW₉O₃₃]^9?, as effective linkages. The magnetic investigation for 1 indicate weak antiferromagnetic interactions for trinuclear Co(II) clusters located in the polyanions.     

Three 3D Cu(II) coordination polymers constructed from 1,2,4,5-benzenetetracarboxylate acid and three positional isomeric ligands

Based on 1,2,4,5-benzenetetracarboxylate acid (H₄btc), and mixed with three isomeric dipyridyl ligands, three novel 3D Cu(II) coordination polymers [Cu₂(btc)(4,4′-bpt)]·2H₂O (1) [4,4′-bpt = 1H-3,5-bis(4-pyridyl)-1,2,4-triazole], [Cu(btc)_0.5(3,4′-bpt)]·0.5H₂O (2) [3,4′-bpt = 1H-3-(3-pyridyl)-5-(4-pyridyl)-1,2,4- triazole] and [Cu(btc)_0.5(3,3′-bpt)]·2H₂O (3) [3,3′-bpt = 1H-3,5-bis(3-pyridyl)-1,2,4-triazole] have been synthesized and characterized, respectively. 1 is a 3D pillared double-layer complex containing a novel bilayer unit; 2 is a 3D pillared-layer architecture with (4,4)-sql layer; 3 exhibits a 3D structure containing 3D [Cu(btc)]_∞ motif and 1D [Cu(bpt)]_∞ chain. The topological analysis shows that 1 can be simplified to a (4,6)-connected network with the Schläfli symbol of (4²·6⁴)₂(4⁸·6⁷), 2 a (4,6)-connected network with the symbol of (4⁴·6²)(4⁴·6¹⁰·8), and 3 a four-connected topology with the symbol of (3²·10³·11)₂(3²·10⁴).     

A sinusoidal chain constructed from decorated Keggin clusters and {Cu(enMe)2}2+ bridging groups in [Cu(enMe)2(H2O)] [{Cu(enMe)2}{Cu(enMe)2(H2O)W12O40(H2)}] · nH2O

A novel organic–inorganic hybrid material, [Cu(enMe)₂(H₂O)][{Cu(enMe)₂}{Cu(enMe)₂(H₂O)W₁₂O₄₀(H₂)}] · nH₂O (n = 0.33, enMe = 1,2-diaminopropane), has been prepared under mild hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR and magnetic susceptibility measurements. It is revealed that the one-dimensional [{Cu(enMe)₂}{Cu(enMe)₂(H₂O)W₁₂O₄₀(H₂)}]²⁻ chain in the structure shows a unique sinusoidal ruffling, which is constructed from decorated Keggin clusters and {Cu(enMe)₂}²⁺ bridging groups through sharing one terminal and one doubly-bridging oxygen atoms of a cluster. The magnetic measurements show that the compound possesses well-separated Cu²⁺ centers. It was indicated that the hybrid exhibits a good catalytic activity in H₂O₂ decomposition.