Facile Synthesis of Hierarchical CuS and CuCo2S4 Structures from an Ionic Liquid Precursor for Electrocatalysis Applications.

Covellite-phase CuS and carrollite-phase CuCo2S4 nano- and microstructures were synthesized from tetrachloridometallate-based ionic liquid precursors using a novel, facile, and highly controllable hot-injection synthesis strategy. The synthesis parameters including reaction time and temperature were first optimized to produce CuS with a well-controlled and unique morphology, providing the best electrocatalytic activity toward the oxygen evolution reaction (OER). In an extension to this approach, the electrocatalytic activity was further improved by incorporating Co into the CuS synthesis method to yield CuCo2S4 microflowers. Both routes provide high microflower yields of >80 wt %. The CuCo2S4 microflowers exhibit a superior performance for the OER in alkaline medium compared to CuS. This is demonstrated by a lower onset potential (∼1.45 V vs RHE @10 mA/cm2), better durability, and higher turnover frequencies compared to bare CuS flowers or commercial Pt/C and IrO2 electrodes. Likely, this effect is associated with the presence of Co3+ sites on which a better adsorption of reactive species formed during the OER (e.g., OH, O, OOH, etc.) can be achieved, thus reducing the OER charge-transfer resistance, as indicated by X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy measurements.

Maytenus disticha Extract and an Isolated ß-Dihydroagarofuran Induce Mitochondrial Depolarization and Apoptosis in Human Cancer Cells by Increasing Mitochondrial Reactive Oxygen Species.

Maytenus disticha (Hook F.), belonging to the Celastraceae family, is an evergreen shrub, native of the central southern mountains of Chile. Previous studies demonstrated that the total extract of M. disticha (MD) has an acetylcholinesterase inhibitory activity along with growth regulatory and insecticidal activities. ß-Dihydroagarofurans sesquiterpenes are the most active components in the plant. However, its activity in cancer has not been analyzed yet. Here, we demonstrate that MD has a cytotoxic activity on breast (MCF-7), lung (PC9), and prostate (C4-2B) human cancer cells with an IC50 (µg/mL) of 40, 4.7, and 5 µg/mL, respectively, an increasing Bax/Bcl2 ratio, and inducing a mitochondrial membrane depolarization. The ß-dihydroagarofuran-type sesquiterpene (MD-6), dihydromyricetin (MD-9), and dihydromyricetin-3-O-ß-glucoside (MD-10) were isolated as the major compounds from MD extracts. From these compounds, only MD-6 showed cytotoxic activity on MCF-7, PC9, and C4-2B with an IC50 of 31.02, 17.58, and 42.19 µM, respectively. Furthermore, the MD-6 increases cell ROS generation, and MD and MD-6 induce a mitochondrial superoxide generation and apoptosis on MCF-7, PC9, and C4-2B, which suggests that the cytotoxic effect of MD is mediated in part by the ß-dihydroagarofuran-type that induces apoptosis by a mitochondrial dysfunction.

Crystal structures of three cyclohexane-based γ-spirolactams: determination of configurations and conformations.

The title compounds, 2-azaspiro[4.5]deca-1-one, C9H15NO, (1a), cis-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1b), and trans-8-methyl-2-azaspiro[4.5]deca-1-one, C10H17NO, (1c), were synthesized from benzoic acids 2 in only 3 steps in high yields. Crystallization from n-hexane afforded single crystals, suitable for X-ray diffraction. Thus, the configurations, conformations, and interesting crystal packing effects have been determined unequivocally. The bicyclic skeleton consists of a lactam ring, attached by a spiro junction to a cyclohexane ring. The lactam ring adopts an envelope conformation and the cyclohexane ring has a chair conformation. The main difference between compound 1b and compound 1c is the position of the carbonyl group on the 2-pyrrolidine ring with respect to the methyl group on the 8-position of the cyclohexane ring, which is cis (1b) or trans (1c). A remarkable feature of all three compounds is the existence of a mirror plane within the molecule. Given that all compounds crystallize in centrosymmetric space groups, the packing always contains interesting enantiomer-like pairs. Finally, the structures are stabilized by intermolecular N-H···O hydrogen bonds.

Metal-Free Regioselective Monocyanation of Hydroxy-, Alkoxy-, and Benzyloxyarenes by Potassium Thiocyanate and Silica Sulfuric Acid as a Cyanating Agent.

A novel and efficient metal- and solvent-free regioselective para-C-H cyanation of hydroxy-, alkoxy-, and benzyloxyarene derivatives has been introduced, using nontoxic potassium thiocyanate as a cyanating reagent in the presence of silica sulfuric acid (SSA). The desired products are obtained in good to high yields without any toxic byproducts.

The 1,6,7,12-Tetraazaperylene Bridging Ligand as an Electron Reservoir and Its Disulfonato Derivative as Redox Mediator in an Enzyme-Electrode Process.

The homodinuclear ruthenium(II) complex [{Ru(l-N4 Me2 )}2 (µ-tape)](PF6 )4 {[1](PF6 )4 } (l-N4 Me2 =N,N'-dimethyl-2,11-diaza[3.3](2,6)-pyridinophane, tape=1,6,7,12-tetraazaperylene) can store one or two electrons in the energetically low-lying π* orbital of the bridging ligand tape. The corresponding singly and doubly reduced complexes [{Ru(l-N4 Me2 )}2 (µ-tape.- )](PF6 )3 {[2](PF6 )3 } and [{Ru(l-N4 Me2 )}2 (µ-tape2- )](PF6 )2 {[3](PF6 )2 }, respectively, were electrochemically generated, successfully isolated and fully characterized by single-crystal X-ray crystallography, spectroscopic methods and magnetic susceptibility measurements. The singly reduced complex [2](PF6 )3 contains the π-radical tape.- and the doubly reduced [3](PF6 )2 the diamagnetic dianion tape2- as bridging ligand, respectively. Nucleophilic aromatic substitution at the bridging tape in [1]4+ by two sulfite units gave the complex [{Ru(l-N4 Me2 )}2 {µ-tape-(SO3 )2 }]2+ ([4]2+ ). Complex dication [4]2+ was exploited as a redox mediator between an anaerobic homogenous reaction solution of an enzyme system (sulfite/sulfite oxidase) and the electrode via participation of the low-energy π*-orbital of the disulfonato-substituted bridging ligand tape-(SO3 )22- (Ered1 =-0.1 V versus Ag/AgCl/1 m KCl in water).

Crystal structure of erioflorin isolated from Podanthus mitiqui (L.).

The title compound, erioflorin, C19H24O6 [systematic name: (1aR,3S,4Z,5aR,8aR,9R,10aR)-1a,2,3,5a,7,8,8a,9,10,10a-deca-hydro-3-hy-droxy-4,10a-dimethyl-8-methyl-idene-7-oxooxireno[5,6]cyclo-deca-[1,2-b]furan-9-yl methacrylate], is a tricyclic germacrane sesquiterpene lactone, which was isolated from Podanthus mitiqui (L.). The compound crystallizes in the space group P212121, and its mol-ecular structure consists of a methacrylic ester of a ten-membered ring sesquiterpenoid annelated with an epoxide and a butyrolactone. The structure is stabilized by one intramolecular C-H⋯O hydrogen bond. An O-H⋯O hydrogen bond and further C-H⋯O interactions can be observed in the packing.

Crystal structures of three bicyclic carbohydrate derivatives.

The title compounds, [(1R,3R,4R,5R,6S)-4,5-bis-(acet-yloxy)-7-oxo-2-oxabi-cyclo[4.2.0]octan-3-yl]methyl acetate, C14H18O8, (I), [(1S,4R,5S,6R)-5-acet-yloxy-7-hy-droxy-imino-2-oxobi-cyclo-[4.2.0]octan-4-yl acetate, C11H15NO6, (II), and [(3aR,5R,6R,7R,7aS)-6,7-bis-(acet-yloxy)-2-oxo-octa-hydro-pyrano[3,2-b]pyrrol-5-yl]methyl acetate, C14H19NO8, (III), are stable bicyclic carbohydrate derivatives. They can easily be synthesized in a few steps from commercially available glycals. As a result of the ring strain from the four-membered rings in (I) and (II), the conformations of the carbohydrates deviate strongly from the ideal chair form. Compound (II) occurs in the boat form. In the five-membered lactam (III), on the other hand, the carbohydrate adopts an almost ideal chair conformation. As a result of the distortion of the sugar rings, the configurations of the three bicyclic carbohydrate derivatives could not be determined from their NMR coupling constants. From our three crystal structure determinations, we were able to establish for the first time the absolute configurations of all new stereocenters of the carbohydrate rings.

Photochemical Synthesis of Both Strained and Macrocyclic (1,7)Naphthalenophanes.

Naphthalenophanes are a special type of cyclophanes. While in the past (1,5)-, (1,6)-, and (1,8)naphthalenophanes were successfully prepared by using the photo-dehydro-Diels-Alder (DDA) reaction, access to (1,7)naphthalenophanes by this method was hitherto unknown. After numerous unsuccessful attempts to prepare these compounds by thermal DDA, we found that the photoinitiated variant (PDDA) represents a very efficient method to [k](1,7)naphthalenophanes 13. The scope ranged from highly strained (k = 11, 12) to macrocyclic products (k = 22, 24). The extraordinary reactivity could be explained by folded ground-state geometries of diketones 12 used as reactants of the PDDA. Furthermore, we calculated the ring-strain energies with the help of an isodesmic reaction and evaluated structural and spectroscopic (NMR) consequences of ring strain.

Study of the Discrepancies between Crystallographic Porosity and Guest Access into Cadmium-Imidazolate Frameworks and Tunable Luminescence Properties by Incorporation of Lanthanides.

An extended member of the isoreticular family of metal-imidazolate framework structures, IFP-6 (IFP=imidazolate framework Potsdam), based on cadmium metal and an in situ functionalized 2-methylimidazolate-4-amide-5-imidate linker is reported. A porous 3D framework with 1D hexagonal channels with accessible pore windows of 0.52 nm has been synthesized by using an ionic liquid (IL) linker precursor. IFP-6 shows significant gas uptake capacity only for CO2 and CH4 at elevated pressure, whereas it does not adsorb N2 , H2 , and CH4 under atmospheric conditions. IFP-6 is assumed to deteriorate at the outside of the material during the activation process. This closing of the metal-organic framework (MOF) pores is proven by positron annihilation lifetime spectroscopy (PALS), which revealed inherent crystal defects. PALS results support the conservation of the inner pores of IFP-6. IFP-6 has also been successfully loaded with luminescent trivalent lanthanide ions (Ln(III) =Tb, Eu, and Sm) in a bottom-up one-pot reaction through the in situ generation of the linker ligand and in situ incorporation of photoluminescent Ln ions into the constituting network. The results of photoluminescence investigations and powder XRD provide evidence that the Ln ions are not doped as connectivity centers into the frameworks, but are instead located within the pores of the MOFs. Under UV light irradiation, Tb@IFP-6 and Eu@IFP-6 (λexc =365 nm) exhibit observable emission changes to a greenish and reddish color, respectively, as a result of strong Ln 4 f emissions.

Tetrabromidocuprates(II)-Synthesis, Structure and EPR.

Metal-containing ionic liquids (ILs) are of interest for a variety of technical applications, e.g., particle synthesis and materials with magnetic or thermochromic properties. In this paper we report the synthesis of, and two structures for, some new tetrabromidocuprates(II) with several "onium" cations in comparison to the results of electron paramagnetic resonance (EPR) spectroscopic analyses. The sterically demanding cations were used to separate the paramagnetic Cu(II) ions for EPR measurements. The EPR hyperfine structure in the spectra of these new compounds is not resolved, due to the line broadening resulting from magnetic exchange between the still-incomplete separated paramagnetic Cu(II) centres. For the majority of compounds, the principal g values (g‖ and g⊥) of the tensors could be determined and information on the structural changes in the [CuBr4](2-) anions can be obtained. The complexes have high potential, e.g., as ionic liquids, as precursors for the synthesis of copper bromide particles, as catalytically active or paramagnetic ionic liquids.

Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties.

Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.

Bis(1,2-dithiosquarato)nickelates(II) - Synthesis, Structure, EPR and Thermal Behavior.

1,2-Dithiosquaratonickelates are available by direct synthesis from metal salts with dipotassium-1,2-dithiosquarate and the appropriate counter cations. The synthesis and characterization, including mass spectrometry, of a series 1,2-dithiosquaratonickelates(II), [Ni(dtsq)2]2-, with several "onium" cations is reported and the X-ray structures of two diamagnetic complexes, (HexPh3N)2[Ni(dtsq)2] and (BuPh3N2[Ni(dtsq)2] with sterically demanding counter ions are presented. The diamagnetic nickel complexes have been doped as host lattices with traces of Cu(II) to measure EPR for additional structural information. The thermal behavior of this series is studied by thermogravimetry and differential thermo analysis (TG/DTA). The thermolysis in air as well as under nitrogen atmosphere of these complexes results in nickel oxide nano-particles in all cases, which are characterized by X-ray powder diffraction.

Dual Role of Acetanilides: Traceless Removal of a Directing Group through Deacetylation/Diazotation and Palladium-Catalyzed C-C-Coupling Reactions.

The acetamide group enables regioselective oxidative ortho-C-H activation reactions, such as Pd-catalyzed acylation. The synthetic utility of these transformations can be significantly enhanced by using the acetamide as a quasi-leaving group in a subsequent conventional Pd-catalyzed coupling or cross-coupling reaction. The concept is illustrated herein for the synthesis of o-alkenyl- and o-arylphenones, which have potential for the synthesis of arylated aromatic heterocycles.

Crystal structure of (2,11-di-aza-[3.3](2,6)pyridino-phane-κ (4) N,N',N'',N''')(1,6,7,12-tetra-aza-perylene-κ (2) N (1),N (12))ruthenium(II) bis-(hexa-fluorido-phosphate) aceto-nitrile 1.422-solvate.

In the title compound, [Ru(C14H16N4)(C16H8N4)](PF6)2·1.422CH3CN, discrete dimers of complex cations, [Ru(L-N4H2)tape](2+) are formed {L-N4H2 = 2,11-di-aza-[3.3](2,6)pyridino-phane; tape = 1,6,7,12-tetra-aza-perylene}, held together by π-π stacking inter-actions via the tape ligand moieties with a centroid-centroid distance of 3.49 (2) Å, assisted by hydrogen bonds between the non-coordinating tape ligand α,α'-di-imine unit and the amine proton of a 2,11-di-aza-[3.3](2,6)-pyridino-phane ligand of the opposite complex cation. The combination of these inter-actions leads to an unusual nearly face-to-face π-π stacking mode. Additional weak C-H⋯N, C-H⋯F, N-H⋯F and P-F⋯π-ring (tape, py) (with F⋯centroid distances of 2.925-3.984 Å) inter-actions are found, leading to a three-dimensional architecture. The Ru(II) atom is coordinated in a distorted octa-hedral geometry, particularly manifested by the Namine-Ru-Namine angle of 153.79 (10)°. The counter-charge is provided by two hexa-fluorido-phosphate anions and the asymmetric unit is completed by aceto-nitrile solvent mol-ecules of crystallization. Disorder was observed for both the hexa-fluorido-phosphate anions as well as the aceto-nitrile solvate mol-ecules, with occupancies for the major moieties of 0.801 (6) for one of the PF6 anions, and a shared occupancy of 0.9215 (17) for the second PF6 anion and a partially occupied aceto-nitrile mol-ecule. A second CH3CN mol-ecule is fully occupied, but 1:1 disordered across a crystallographic inversion center.

Imidazolium 2-substituted 4,5-dicyanoimidazolate ionic liquids: synthesis, crystal structures and structure-thermal property relationships.

Thirty six novel ionic liquids (ILs) with 1-butyl-3-methylimidazolium and 3-methyl-1-octylimidazolium cations paired with 2-substitited 4,5-dicyanoimidazolate anions (substituent at C2 = chloro, bromo, methoxy, vinyl, amino, methyl, ethyl, propyl, isopropyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl and phenyl) have been synthesized and characterized by using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and single-crystal X-ray crystallography. The effects of cation and anion type and structure on the thermal properties of the resulting ionic liquids, including several room temperature ionic liquids (RTILs) are examined and discussed. ILs exhibited large liquid and crystallization ranges and formed glasses on cooling with glass transition temperatures in the range of -22 to -68 °C. The effects of alkyl substituents of the imidazolate anion reflected the crystallization, melting points and thermal decomposition of the ILs. The Coulombic packing force, van der Waals forces and size of the anions can be considered for altering the thermal transitions. Three crystal structures of the ILs were determined and the effects of changes to the cations and anions on the packing of the structure were investigated.

(1,6,7,12-Tetra-aza-perylene-κ(2) N,N')bis-(4,4',5,5'-tetra-methyl-2,2'-bipyridyl-κ(2) N,N')ruthenium(II) bis-(hexa-fluorido-phosphate) aceto-nitrile tris-olvate.

In the title compound, rac-[Ru(C14H16N2)2(C16H8N4)](PF6)2·3C2H3N, discrete dimers of complex cations, [Ru(tmbpy)2-tape](2+), of opposite chirality are formed (tmbpy = tetra-methyl-bipyridine; tape = tetraazaperylene), held together by π-π stacking inter-actions between the tetra-aza-perylene moieties with centroid-centroid distances in the range 3.563 (3)-3.837 (3) Å. These inter-actions exhibit a parallel displaced π-π stacking mode. Additional weak C-H⋯π-ring and C-H⋯N and C-H⋯F inter-actions are found, leading to a three-dimensional architecture. The Ru(II) atom is coordinated in a distorted octa-hedral geometry. The counter-charge is provided by two hexa-fluorido-phosphate anions and the asymmetric unit is completed by three aceto-nitrile solvent mol-ecules of crystallization. Four F atoms of one PF6 (-) anion are disordered over three sets of sites with occupancies of 0.517 (3):0.244 (3):0.239 (3). Two aceto-nitrile solvent mol-ecules are highly disordered and their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155].

A supramolecular Co(II)14-metal-organic cube in a hydrogen-bonded network and a Co(II)-organic framework with a flexible methoxy substituent.

The reaction of 4,5-dicyano-2-methoxyimidazole (L1) with Co(NO3)2·6H2O under solvothermal conditions in DMF, a MOF, and a hydrogen-bonded network consisting of tetradecanuclear Co(ii)14-metal organic cube () are achieved. shows the bcu net with 14 cobalt atoms.

µ-1,6,7,12-Tetra-aza-perylene-κ(4) N (1),N (12):N (6),N (7)-bis-[chlorido-(η(6)-p-cymene)ruthenium(II)] bis-(hexa-fluorido-phosphate) acetone disolvate.

In the title compound, [Ru2(C10H14)2Cl2(C16H8N4)](PF6)2·2C3H6O, the binuclear Ru(II) complex dication, [{RuCl(η(6)-cym)}2(µ-tape)](2+), built up by a planar 1,6,7,12-tetra-aza-perylene (tape) bridge, two η(6)-bound cymene (cym) ligands and two chloride ligands, includes an inversion center. The Ru(II) atom shows the typical piano-stool motif for arene coordination. The counter-charge is provided by a hexa-fluorido-phosphate anion and the asymmetric unit is completed by an acetone mol-ecule of crystallization. The components of the structure are connected into a three-dimensional architecture by C-H⋯O/F/Cl inter-actions.

Giant Zn14 molecular building block in hydrogen-bonded network with permanent porosity for gas uptake.

In situ imidazolate-4,5-diamide-2-olate linker generation leads to the formation of a [Zn14(L2)12(O)(OH)2(H2O)4] molecular building block (MBB) with a Zn6 octahedron inscribed in a Zn8 cube. The MBBs connect by amide-amide hydrogen bonds to a 3D robust supramolecular network which can be activated for N2, CO2, CH4, and H2 gas sorption.