Synthesis and Crystal Structures of Mn(II) and Co(II) Complexes as Catalysts for Oxidation of Cyclohexanone

The global demand on adipic usage in the production of plasticizers and synthetic polyamide is increasing. In line with the search for an efficient and energy-conserving way to isolate adipic acid (AA) in good yields, this paper introduces the oxidization of cyclohexanone utilizing two new coordination compounds, [Mn(2,6-pydc)2](imi) (1) and [Co(H2pza)2(H2O)2(NO3)].NO3 (2), as catalysts. Compounds 1 and 2 were synthesized by room temperature and refluxing methods, and characterized by spectral analyses (IR and UV-Vis.), SEM, BET, TGA, elemental, and X-ray crystallography. The single crystal structure of compound 1 revealed that pyridinedicarboxylate (2,6-pydc) and imidazole (imi) moieties were coordinated to the Mn(II) atom through imine nitrogen and deprotonated oxygen atoms, to form an undistorted octahedral coordination geometry with the N2O4 donor set. The axial and equatorial planes containing O2, O4, O5, and O7 atoms were from two adjacent 2,6-pydc ligands which formed the unidendate donor ligand; imi, on the other hand, acted as a bidendate donor ligand. For compound 2, the Co(II) atom was being coordinated by two pyrazinamide (H2pza) moieties, which acted as an unidendate donor ligand; two water molecules occupying the axial position, and one nitrate molecule occupying the apical position, were within the coordination sphere; a nitrate molecule was disordered outside the coordination sphere. The distance, 4.658 Å, between the Co1 atom and the N8 atom of the uncoordinated nitrate molecule, was within the range reported elsewhere. Cyclohexanone peroxidation experiments revealed that compound 1 exhibited unique catalytic performance by giving a 72.8% yield in adipic acid, in comparison to the 71.3% yield obtained with compound 2. The yields in AA were maintained by way of recyclability evaluation. The reaction kinetics of compound 2 gave less activation energy, Ea 2938 J mol−1, while the thermodynamic parameters indicated that the chemical reactivity of cyclohexanone on the active surfaces of compounds 1 and 2 was via monolayer physisorption.

Designing and Construction of Polyaromatic Group Containing Cd(II)-based Coordination Polymers for Solvent-free Strecker-type Cyanation of Acetals

In the present work, we have synthesized and characterized two novel Cd(II) coordination polymers, [Cd4(L1)4(DMF)6]n.3n(DMF) (1) and [Cd2(L2)2(DMF)3]n.2n(DMF) (2), and studied their catalytic application. They were synthesized via solvothermal reaction...

Water-soluble Al(iii), Fe(iii) and Cu(ii) formazanates: synthesis, structure, and applications in alkane and alcohol oxidations

The synthesis, structure and catalytic performance of water-soluble Al(iii), Fe(iii) and Cu(ii) formazanates in the oxidation of cyclohexane and cyclohexanol to the coresponding organic products are reported.

A novel sulfate-bridged binuclear copper(ii) complex: structure, optical, ADMET and in vivo approach in a murine model of bone metastasis

A novel complex, formulated as [Cu₂(μ₃-SO₄)₂(C₄H₆N₂)₄], showed significant ameliorative effects on tumor osteolytic lesions in malignant Walker 256/B breast cancer-induced bone metastases.

Cyanosilylation of Aldehydes Catalyzed by Ag(I)- and Cu(II)-Arylhydrazone Coordination Polymers in Conventional and in Ionic Liquid Media

The novel Ag(I) and Cu(II) coordination polymers [Ag(μ3-1κO;2:3κO′;4κN-HL)]n∙n/2H2O (1) and [Cu(en)2(μ-1κO;2κN-L)]n∙nH2O (2) [HL− = 2-(2-(1-cyano-2-oxopropylidene)hydrazinyl)benzene sulfonate] were synthesized and characterized by IR and ESI-MS spectroscopies, elemental and single crystal X-ray diffraction analyses. Compounds 1 and 2 as well as the already known complex salt [Cu(H2O)2(en)2](HL)2 (3) have been tested as homogenous catalysts for the cyanosilylation reaction of different aldehydes with trimethylsilyl cyanide, to provide cyanohydrin trimethylsilyl ethers. Coordination polymer 2 was found to be the most efficient one, with yields ranging from 76 to 88% in methanol, which increases up to 99% by addition of the ionic liquid [DHTMG][L-Lactate].

Crystal structure of [1,3-bis-(2,4,6-tri-methyl-phen-yl)imidazolidin-2-yl-idene]di-chlorido-{2-[1-(di-methyl-amino)-eth-yl]benzyl-idene}ruthenium including an unknown solvate

The title compound, [RuCl2(C21H26N2)(C11H15N)], is an example of a new generation of N,N-dialkyl metallocomplex ruthenium catalysts with an N→Ru coordination bond as part of a six-membered chelate ring. The Ru atom has an Addison τ parameter of 0.234, which indicates a geometry inter-mediate between square-based pyramidal and trigonal-bipyramidal. The complex shows the usual trans arrangement of the two chloride ligands, with Ru-Cl bond lengths of 2.3397 (8) and 2.3476 (8) Å, and a Cl-Ru- Cl angle of 157.47 (3)°. The crystal structure features C-H⋯Cl, C-H⋯π and π-π stacking inter-actions. The solvent mol-ecules were found to be highly disordered and their contribution to the scattering was removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9-18], which indicated a solvent cavity of volume 1096 Å3 containing approximately 419 electrons. These solvent mol-ecules are not considered in the given chemical formula and other crystal data.

Crystal structure and Hirshfeld surface analysis of (E)-1-[2,2-di-chloro-1-(4-nitro-phen-yl)ethen-yl]-2-(4-fluoro-phen-yl)diazene

In the title compound, C14H8Cl2FN3O2, the 4-fluoro-phenyl ring and the nitro-substituted benzene ring form a dihedral angle of 63.29 (8)°. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds into chains running parallel to the c axis. The crystal packing is further stabilized by C-Cl⋯π, C-F⋯π and N-O⋯π inter-actions. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions to the crystal packing are from H⋯O/O⋯H (15.5%), H⋯H (15.3%), Cl⋯H/H⋯Cl (13.8%), C⋯H/H⋯C (9.5%) and F⋯H/H⋯F (8.2%) inter-actions.

Arylhydrazone ligands as Cu-protectors and -catalysis promoters in the azide-alkyne cycloaddition reaction

A series of water soluble copper(ii) complexes, [Cu(κO¹O²N-H₂L¹)(H₂O)₂]·2H₂O (2), [Cu(κO-H₃L¹)₂(H₂O)₄] (3), [Cu(κO-H₄L²)₂(H₂O)₄] (5) and [Cu(H₂O)₆]·2H₂L³·2(CH₃)₂NCHO (7), were prepared by the reaction of Cu(NO₃)₂·3H₂O with sodium (Z)-2-(2-(1-amino-1,3-dioxobutan-2-ylidene)hydrazineyl)benzenesulfonate, [Na(μ₄-1:2κO¹,2κO²,3κO³,4κO⁴-H₃L¹)]_n (1; for 2 and 3), sodium (Z)-3-(2-(1-amino-1,3-dioxobutan-2-ylidene)hydrazineyl)-4-hydroxybenzene-sulfonate, [Na(μ-1κO¹,2κO²-H₄L²)]₂ (4; for 5) or sodium (Z)-2-(2-(1,3-dioxo-1-(phenylamino)butan-2-ylidene)hydrazineyl)naphthalene-1-sulfonate, [Na(μ-1κO¹O²,2κO³-H₂L³)(CH₃OH)₂]₂ (6; for 7). Compounds 1-7 were fully characterized, also by single-crystal X-ray diffraction analysis, and applied as homogeneous catalysts for the azide-alkyne cycloaddition (AAC) reaction to afford 1,4-disubstituted 1,2,3-triazoles. A structure-catalytic activity relationship has been recognized for the first time on the basis of the occurrence of resonance- and charge-assisted hydrogen bond interactions (RAHB and CAHB), in charge and ligand binding modes, enabling the catalytic activity of the compounds to be ordered as follows: Cu(NO₃)₂≪7 (complex salt with RAHB and CAHB) < 3 (with RAHB and CAHB) < 5 (with RAHB) < 2 (neither RAHB nor CAHB). Complex 2, without such non-covalent interactions, was found to be the most efficient catalyst for the AAC reaction, affording up to 98% product yield after being placed for 15 min, at 125 °C, in a water/acetonitrile mixture under low power (10 W) MW irradiation.

Copper(II) Complexes of Arylhydrazone of 1H-Indene-1,3(2H)-dione as Catalysts for the Oxidation of Cyclohexane in Ionic Liquids

The copper(II) complexes [CuL(H2O)2]∙H2O (1) and [CuL(dea)] (2) [L = 2-(2-(1,3-dioxo-1H-inden-2(3H)-ylidene)hydrazinyl)benzenesulfonate, dea = diethanolamine] were applied as catalysts in the peroxidative (with tert-butyl-hydroperoxide or hydrogen peroxide) conversion of cyclohexane to cyclohexanol and cyclohexanone, either in acetonitrile or in any of the ionic liquids [bmim][NTf2] and [hmim][NTf2] [bmim = 1-butyl-3-methylimidazolium, hmim = 1-hexyl-3-methylimidazolium, NTf2 = bis(trifluoromethanesulfonyl) imide]. Tert-butyl-hydroperoxide led to better product yields, as compared to H2O2, with a selectivity directed towards cyclohexanone. The ILs showed a better performance than the conventional solvent for the copper complex 1. No catalytic activity was observed for 2 in the presence of an IL.

Crystal structure of dimethyl (3aS,6R,6aS,7S)-1H,3H,6H,7H-3a,6:7,9a-diepoxybenzo[de]isochromene-3a 1,6a-dicarboxylate, C16H16O7

C16H16O7, monoclinic, P21/n (no. 14), a = 12.830(3) Å, b = 8.1101(16) Å, c = 14.900(3) Å, β = 114.88(3)°, V = 1406.5(6) Å3, Z = 4, R gt(F) = 0.0578, wR ref(F 2) = 0.1799, T = 100(2) K.

Synthesis of Metallomacrocycle and Coordination Polymers with Pyridine-Based Amidocarboxylate Ligands and Their Catalytic Activities towards the Henry and Knoevenagel Reactions

The reactions of 3,3'-{(pyridine-2,6-dicarbonyl)bis(azanediyl)}dibenzoic acid (H2L) with zinc(II), cadmium(II), and samarium(III) nitrates were studied, and the obtained compounds, [Zn(1κO:2κO'-L)(H2O)2] n (1), [Cd(1κO 2:2κO 2-L)(H2O)2]2 ⋅6n H2O⋅ n C4H8O2 ⋅1.5n DMF (2), and [Sm(1κO:2κO'O'':3κO'''-L)(NO3)(H2O)(dmf)] n ⋅ n DMF (3), were characterized by elemental analysis, FTIR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. Compounds 1 and 3 have 1D zigzag- and double-chain-type structures, respectively, whereas 2 features a dinuclear metallomacrocyclic complex. The ligand (L2-) orients in different conformations, that is, syn-syn for 1 and anti-anti for 2 and 3. Compound 1 is the first example in which the syn-syn conformation for this ligand has been observed. These compounds act as heterogeneous catalysts for the nitroaldol (Henry; in water medium) and Knoevenagel condensation reactions of different aldehydes, and the most effective is zinc coordination polymer 1. Recyclability, heterogeneity, and size-selectivity tests were performed, which showed that the catalyst was highly active over at least four recycling runs.

Crystal structure and Hirshfeld surface analysis of ethane-1,2-diaminium 3-[2-(1,3-dioxo-1,3-di-phenyl-propan-2-yl-idene)hydrazin-yl]-5-nitro-2-oxido-benzene-sulfonate dihydrate

In the anion of the title hydrated salt, C2H10N22+·C21H13N3O8S2-·2H2O, the planes of the phenyl rings and the benzene ring of the 5-nitro-2-oxido-benzene-sulfonate group are inclined to one another by 44.42 (11), 56.87 (11) and 77.70 (12)°. In the crystal, the anions are linked to the cations and the water mol-ecules by N-H⋯O and O-H⋯O hydrogen bonds, forming a three-dimensional network. Furthermore, there are face-to-face π-π stacking inter-actions between the centroids of one phenyl ring and the benzene ring of the 5-nitro-2-oxido-benzene-sulfonate group [centroid-centroid distance = 3.8382 (13) Å and slippage = 1.841 Å]. A Hirshfeld surface analysis was conducted to verify the contributions of the different inter-molecular inter-actions.

Structure of copper(II) complexes grown from ionic liquids - 1-ethyl-3-methyl-imidazolium acetate or chloride

Crystals of four new copper(II) complexes have been grown from copper(II) acetate/chloride-1-ethyl-3-methyl-imidazolium acetate/chloride-water systems and characterized by X-ray analysis. The first complex, bis-(1-ethyl-3-methyl-imidazolium) tetra-μ-acetato-bis[chloridocuprate(II)], [Emim]2[Cu2(C2H3O2)4Cl2] (1) (Emim is 1-ethyl-3-methyl-imidazolium, C6H11N2), contains [Cu2(C2H3O2)4Cl2]2- coordination anions with a paddle-wheel structure and ionic liquid cations. Two of the synthesized complexes are one-dimensional polymers, namely catena-poly[1-ethyl-3-methyl-imidazolium [[tetra-μ-acetato-dicuprate(II)]-μ-chlorido] monohydrate], {[Emim][Cu2(C2H3O2)4Cl]·H2O} n (2), and catena-poly[1-ethyl-3-methyl-imidazolium [[tetra-μ-acetato-dicuprate(II)]-μ-acetato]], {[Emim][Cu2(C2H3O2)5]} n (3). In these compounds, the Cu2(C2H3O2)4 units with a paddle-wheel structure are connected to each other through chloride (in 2) or acetate (in 3) anions to form parallel chains, between which cations of ionic liquid are situated. The last compound, bis-(1-ethyl-3-methyl-imidazolium) tetra-μ-acetato-bis[aquacopper(II)] tetra-μ-acetato-bis[acetatocuprate(II)] dihydrate, [Emim]2[Cu2(C2H3O2)4(H2O)2][Cu2(C2H3O2)6]·2H2O (4), contains two different binuclear coordination units (neutral and anionic), connected through hydrogen bonds between water mol-ecules and acetate ions.

Lanthanide metal organic frameworks based on dicarboxyl-functionalized arylhydrazone of barbituric acid: syntheses, structures, luminescence and catalytic cyanosilylation of aldehydes

Ln(iii) MOFs act as recyclable heterogeneous catalysts for the cyanosilylation of aldehydes.

A Cu(ii) MOF with a flexible bifunctionalised terpyridine as an efficient catalyst for the single-pot hydrocarboxylation of cyclohexane to carboxylic acid in water/ionic liquid medium

A bifunctionalised terpyridine based Cu(ii) MOF for efficient hydrocarboxylation of cyclohexane to cyclohexanecarboxylic acid in an ionic liquid medium.

ZnII and CdII MOFs based on an amidoisophthalic acid ligand: synthesis, structure and catalytic application in transesterification

Metal–organic frameworks of Zn(ii) and Cd(ii) act as recyclable heterogeneous catalysts for the transesterification reaction of carboxylate esters.

pH dependent synthesis of Zn(ii) and Cd(ii) coordination polymers with dicarboxyl-functionalized arylhydrazone of barbituric acid: photoluminescence properties and catalysts for Knoevenagel condensation

Coordination polymers of Zn(ii) and Cd(ii) act as recyclable heterogeneous catalysts for Knoevenagel condensation reaction of aldehydes with malononitrile.

Syntheses and crystal structures of benzene-sulfonate and -carboxylate copper polymers and their application in the oxidation of cyclohexane in ionic liquid under mild conditions

Enhanced catalytic activities of copper polymers for the peroxidative oxidation of cyclohexane are observed in an ionic liquid medium.

Re-evaluating selectivity as a determining factor in peroxidative methane oxidation by multimetallic copper complexes

A series of multimetallic copper(ii) complexes have been re-investigated for methane oxidation with H₂O₂.