Continuous Dehydrogenation of n‐Pentanol over a Cr Modified Cu/γ‐Al2O3‐La2O3 Catalyst

The oxidant‐free dehydrogenation of n‐pentanol over copper based catalysts was investigated in this paper. The effect of metal modification on the activity and stability of the copper catalyst supported on γ‐Al₂O₃ and La₂O₃ (Cu/γ‐Al₂O₃‐La₂O₃) was clarified and a Cr modified Cu/Al₂O₃‐La₂O₃ (Cu‐Cr/γ‐Al₂O₃‐La₂O₃) showed the best catalytic performance. The conversion of n‐pentanol was 70.0% and the selectivity for n‐pentanal increased to 97.1% over Cu‐Cr/γ‐Al₂O₃‐La₂O₃. X‐ray diffraction and temperature programmed reduction of H₂ indicated that the addition of Cr favors the formation and reduction of the copper oxide, and the dispersion of the active Cu⁰ species, accounting for the good activity and stability of this catalyst. Furthermore, the lower amount of acidic sites in Cu‐Cr/γ‐Al₂O₃‐La₂O₃ is suggested to suppress the dehydration in oxidant‐free dehydrogenation of n‐pentanol, accounting for the higher selectivity for n‐pentanal.     

Characterization and Activity of Cu‐MnOx/γ‐Al2O3 Catalyst for Hydrogenation of Carbon Dioxide

The effect of manganese on the dispersion, reduction behavior and active states of surface of supported copper oxide catalysts have been investigated by XRD, temperature‐programmed reduction and XPS. The activity of methanol synthesis from CO₂/H₂ was also investigated. The catalytic activity over CuO‐MnO_x/γ‐Al₂O₃ catalyst for CO₂ hydrogenation is higher than that of CuO/γ‐Al₂O₃. The adding of manganese is beneficial in enhancing the dispersion of the supported copper oxide and make the TPR peak of the CuO‐MnK_x/γ‐Al₂O₃ catalyst different from the individual supported copper and manganese oxide catalysts, which indicates that there exists strong interaction between the copper and manganese oxide. For the CuO/γ‐Al₂O₃ catalyst there are two reducible copper oxide species; α and β peaks are attributed to the reduction of highly dispersed copper oxide species and bulk CuO species, respectively. For the CuO‐MnO_x/γ‐Al₂O₃ catalyst, four reduction peaks are observed, α peak is attributed to the dispersed copper oxide species; β peak is ascribed to the bulk CuO; γ peak is attributed to the reduction of high dispersed CuO interacting with manganese; δ peak may be the reduction of the manganese oxide interacting with copper oxide. XPS results show that Cu⁺ mostly existed on the working surface of the Cu‐Mn/γ‐Al₂O₃ catalysts. The activity was promoted by Cu with positive charge which was formed by means of long path exchange function between Cu? O? Mn. These results indicate that there is synergistic interaction between the copper and manganese oxide, which is responsible for the high activity of CO₂ hydrogenation.     

[1‐Allylpyridinium][Cu2Cl3]: Synthesis,X‐ray Structure and the Regularity of Crystal Architecture of 1‐Allyl/(amino)‐pyridinium Copper(I) Chloride π‐Complexes

By alternating‐current electrochemical technique crystals of copper(I) π‐complex with 1‐allylpyridinium chloride of [C₅H₅N(C₃H₅)][Cu₂Cl₃] ( 1 ) composition have been obtained and structurally investigated. Compound 1 crystallizes in monoclinic system, space group C2/c a = 24.035(1) Å, b = 11.4870(9) Å, c = 7.8170(5) Å, β = 95.010(5)°, V = 2150.0(2) ų (at 100 K), Z = 8, R = 0.028, for 4836 independent reflections. In the structure 1 trigonal‐pyramidal environment of π‐coordinated copper(I) atom is formed by a lengthened to 1.376(2) Å C=C bond of allyl group and by three chlorine atoms. Other two copper atoms are tetrahedrally surrounded by chlorine atoms only. The coordination polyhedra are combined into an original infinite (Cu₄Cl₆^2—)_n fragment. Structural comparison of 1 and the recently studied copper(I) chloride π‐complexes with 3‐amino‐, 2‐amino‐, 4‐amino‐1‐allylpyridinium chlorides of respective [LCu₂Cl₃] ( 2 ), [L₂Cu₂Cl₄] ( 3 ), and [LCuCl₂] ( 4 ) compositions allowed us to reveal the trend of the inorganic fragment complication which depends on pKa (base) value of the corresponding initial heterocycle.     

Three p‐xylene‐solvated pseudopolymorphs of bis[1,3‐bis(pentafluorophenyl)propane‐1,3‐dionato]copper(II)

The Cu²⁺ ions in the title compounds, namely bis[1,3‐bis(pentafluorophenyl)propane‐1,3‐dionato‐κ²O,O′]copper(II) p‐xylene n‐solvate, [Cu(C₁₅HF₁₀O₂)₂]·nC₈H₁₀, with n = 1, (I), n = 2, (II), and n = 4, (III), are coordinated by two 1,3‐bis(pentafluorophenyl)propane‐1,3‐dionate ligands. The coordination complexes of (I) and (II) have crystallographic inversion symmetry at the Cu atom and the p‐xylene molecule in (I) also lies across an inversion centre. The p‐xylene molecules in (I) and (II) interact with the pentafluorophenyl groups of the complex via arene–perfluoroarene interactions. In the crystal of (III), two of the p‐xylene molecules interact with the pentafluorophenyl groups via arene–perfluoroarene interactions. The other two p‐xylene molecules are located on the CuO₄ coordination plane, forming a uniform cavity produced by metal...π interactions.     

Two novel organic–inorganic hybrid materials from tetrachloridometallate(II) salts and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium

Two organic–inorganic hybrid compounds have been prepared by the combination of the 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium cation with perhalometallate anions to give 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridocobaltate(II), (C₁₂H₁₂N₂)[CoCl₄], (I), and 4‐[(E)‐2‐(pyridin‐1‐ium‐2‐yl)ethenyl]pyridinium tetrachloridozincate(II), (C₁₂H₁₂N₂)[ZnCl₄], (II). The compounds have been structurally characterized by single‐crystal X‐ray diffraction analysis, showing the formation of a three‐dimensional network through X—H...Cl_nM⁻ (X = C, N⁺; n = 1, 2; M = Co^II, Zn^II) hydrogen‐bonding interactions and π–π stacking interactions. The title compounds were also characterized by FT–IR spectroscopy and thermogravimetric analysis (TGA).     

Chemical Fixation of CO2 and Other Heterogeneous Catalytic Studies by Employing a Layered Cu‐Porphyrin Prepared Through Single‐Crystal to Single‐Crystal Exchange of a Zn Analogue

A solvothermal reaction of Zn(NO₃)₂ ? 6 H₂O, tetra‐(4‐pyridyl)porphyrin (H₂TPyP), and 4,4′‐oxybis(benzoic acid) (H₂OBA) resulted in a new two‐dimensional Zn‐ porphyrin metal–organic framework compound, [Zn₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₆ ( 1 ; DMA=N,N‐dimethylacetamide). The Zn^II ions present in 1 could be exchanged by using a solution of Cu(NO₃)₂ ? 3 H₂O in DMA at room temperature to give [Cu₂(C₄₀H₂₄N₈)_0.5(C₁₄H₈O₅)(DMA)](DMA)(H₂O)₃ ( Cu∈1 ). The extra‐framework solvent molecules have been shown to be reversibly removed or exchanged without collapse of the framework. Solvent‐free Cu∈1 was explored as an active heterogeneous catalyst towards three different organic reactions: 1) the chemical fixation of CO₂ into cyclic carbonate at room temperature and 1 atm; 2) the nitroaldol reaction under solvent‐free conditions, and 3) the three‐component coupling of aminopyridine, benzaldehyde, and aryl alkynes followed by 5‐exo‐dig cyclization to produce the important pharmacophore imidazopyridine.     

Nitrogen‐doped C60 as a robust catalyst for CO oxidation

The O₂ activation and CO oxidation on nitrogen‐doped C₅₉N fullerene are investigated using first‐principles calculations. The calculations indicate that the C₅₉N fullerene is able to activate O₂ molecules resulting in the formation of superoxide species ( ) both kinetically and thermodynamically. The active superoxide can further react with CO to form CO₂ via the Eley–Rideal mechanism by passing a stepwise reaction barrier of only 0.20 eV. Ab initio molecular dynamics (AIMD) simulation is carried out to evidence the feasibility of the Eley–Rideal mechanism. In addition, the second CO oxidation takes place with the remaining atomic O without any activation energy barrier. The full catalytic reaction cycles can occur energetically favorable and suggest a two‐step Eley–Rideal mechanism for CO oxidation with O₂ catalyzed by the C₅₉N fullerene. The catalytic properties of high percentage nitrogen‐doped fullerene (C₄₈N₁₂) is also examined. This work contributes to designing higher effective carbon‐based materials catalysts by a dependable theoretical insight into the catalytic properties of the nitrogen‐doped fullerene. © 2017 Wiley Periodicals, Inc.     

Enzyme‐free Cu2O@MnO2/GCE for Hydrogen Peroxide Sensing

A novel composite material of copper (I) oxide at manganese (IV) oxide (Cu₂O@MnO₂), was synthesized and applied for modification on the glassy carbon electrode (GCE) surface (Cu₂O@MnO₂/GCE) as a hydrogen peroxide (H₂O₂) sensor. The composite material was characterized regarding its structural and morphological properties, using field emission scanning electron microscopy (FE‐SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The Cu₂O@MnO₂/GCE showed an excellent electrocatalytic response to the oxidation of H₂O₂ which provided a 0.56 s^?1 charge transfer rate constant (K_s), 1.65×10^?5 cm² s^?1 diffusion coefficient value (D), 0.12 mm² electroactive surface area (A_e) and 1.04×10^?8 mol cm^?2 surface concentration ( ). At the optimal condition, the constructed sensor exhibited a wide linear range from 0.5 μM to 20 mM with a low limit of detection (63 nM, (S/N=3) and a good sensitivity of 256.33 μA mM^?1 cm^?2. It also presented high stability (ΔI_response±15 %, n=100), repeatability (1.25 %RSD, n=10) and reproducibility (3.55 %RSD, n=10). The results indicated that the synthesized Cu₂O@MnO₂ was successfully used as a new platform for H₂O₂ sensing.     

Three oxo complexes with a tetra­nuclear [Cu4(μ2‐Cl)6(μ4‐O)] unit

The three title compounds, namely 4‐phenyl‐1H‐imidazolium hexa‐μ₂‐chloro‐chloro‐μ₄‐oxo‐tris­(4‐phenyl‐1H‐imidazole‐κN¹)­tetra­copper(II) monohydrate, (C₉H₉N₂)[Cu₄Cl₇O(C₉H₈N₂)₃]·H₂O, hexa‐μ₂‐chloro‐μ₄‐oxo‐tetra­kis­(pyridine N‐oxide‐κO)tetra­copper(II), [Cu₄Cl₆O(C₅H₅NO)₄], and hexa‐μ₂‐chloro‐tetra­kis(2‐methyl‐1H‐imidazole‐κN¹)‐μ₄‐oxo‐tetra­copper(II) methanol trisolvate, [Cu₄Cl₆O(C₄H₆N₂)₄]·3CH₄O, exhibit the same Cu₄OCl₆ framework, where the O atom at the centre of an almost regular tetra­hedron bridges four copper cations at the corners. This group is in turn surrounded by a Cl₆ octa­hedron, leading to a rather globular species. This special arrangement of the Cu^II cations results in a diversity of magnetic behaviours.     

Two centrosymmetric dinuclear phenanthroline–copper(II) complexes with 3,5‐dichloro‐2‐hydroxybenzoic acid and 5‐chloro‐2‐hydroxybenzoic acid

The title compounds, bis(μ‐3,5‐dichloro‐2‐oxidobenzoato)‐κ³O¹,O²:O²;κ³O²:O¹,O²‐bis[(3,5‐dichloro‐2‐hydroxybenzoic acid‐κO¹)(1,10‐phenanthroline‐κ²N,N′)copper(II)], [Cu₂(C₇H₂Cl₂O₃)₂(C₇H₄Cl₂O₃)₂(C₁₂H₈N₂)₂], (I), and bis(μ‐5‐chloro‐2‐oxidobenzoato)‐κ³O¹,O²:O¹;κ³O¹:O¹,O²‐bis[(5‐chloro‐2‐hydroxybenzoic acid‐κO¹)(1,10‐phenanthroline‐κ²N,N′)copper(II)] ethanol monosolvate, [Cu₂(C₇H₃ClO₃)₂(C₇H₅ClO₃)₂(C₁₂H₈N₂)₂]·C₂H₆O, (II), contain centrosymmetric dinuclear complex molecules in which Cu²⁺ cations are surrounded by a chelating 1,10‐phenanthroline ligand, a chelating 3,5‐dichloro‐2‐oxidobenzoate or 5‐chloro‐2‐oxidobenzoate anionic ligand and a monodentate 3,5‐dichloro‐2‐hydroxybenzoic acid or 5‐chloro‐2‐hydroxybenzoic acid ligand. The chelating benzoate ligand also bridges to the other Cu²⁺ ion in the molecule, but the O atom involved in the bridge is different in the two complexes, being the phenolate O atom in (I) and a carboxylate O atom in (II). The bridge completes a 4+1+1 axially elongated tetragonal–bipyramidal arrangement about each Cu²⁺ cation. The complex molecules of both compounds are linked into one‐dimensional supramolecular chains through O—H...O hydrogen bonds.     

Analysis of High and Selective Uptake of CO2 in an Oxamide‐Containing {Cu2(OOCR)4}‐Based Metal–Organic Framework

The porous framework [Cu₂(H₂O)₂L] ? 4 H₂O ? 2 DMA (H₄L=oxalylbis(azanediyl)diisophthalic acid; DMA=N,N‐dimethylacetamide), denoted NOTT‐125, is formed by connection of {Cu₂(RCOO)₄} paddlewheels with the isophthalate linkers in L^4?. A single crystal structure determination reveals that NOTT‐125 crystallises in monoclinic unit cell with a=27.9161(6), b=18.6627(4) and c=32.3643(8) Å, β=112.655(3)°, space group P2₁/c. The structure of this material shows fof topology, which can be viewed as the packing of two types of cages (cage A and cage B) in three‐dimensional space. Cage A is constructed from twelve {Cu₂(OOCR)₄} paddlewheels and six linkers to form an ellipsoid‐shaped cavity approximately 24.0 Å along its long axis and 9.6 Å across its central diameter. Cage B consists of six {Cu₂(OOCR)₄} units and twelve linkers and has a spherical diameter of 12.7 Å taking into account the van der Waals radii of the atoms. NOTT‐125 incorporates oxamide functionality within the pore walls, and this, combined with high porosity in desolvated NOTT‐125a, is responsible for excellent CO₂ uptake (40.1 wt % at 273 K and 1 bar) and selectivity for CO₂ over CH₄ or N₂. Grand canonical Monte Carlo (GCMC) simulations show excellent agreement with the experimental gas isotherm data, and a computational study of the specific interactions and binding energies of both CO₂ and CH₄ with the linkers in NOTT‐125 reveals a set of strong interactions between CO₂ and the oxamide motif that are not possible with a single amide.     

Metal–Organic Framework‐Derived Carbon Nanorods Encapsulating Bismuth Oxides for Rapid and Selective CO2 Electroreduction to Formate

Carbon dioxide (CO₂) conversion is promising in alleviating the excessive CO₂ level and simultaneously producing valuables. This work reports the preparation of carbon nanorods encapsulated bismuth oxides for the efficient CO₂ electroconversion toward formate production. This resultant catalyst exhibits a small onset potential of ?0.28 V vs. RHE and partial current density of over 200 mA cm^?2 with a stable and high Faradaic efficiency of 93 % for formate generation in a flow cell configuration. Electrochemical results demonstrate the synergistic effect in the Bi₂O₃@C promotes the rapid and selective CO₂ reduction in which the Bi₂O₃ is beneficial for improving the reaction kinetics and formate selectivity, while the carbon matrix would be helpful for enhancing the activity and current density of formate production. This work provides effective bismuth‐based MOF derivatives for efficient formate production and offers insights in promoting practical CO₂ conversion technology.     

An unusual coordination polymer containing Cu+ ions and featuring possible Cu...Cu `cuprophilic' interactions: poly[di‐μ‐chlorido‐(μ4‐3,5‐diaminobenzoato‐κ4O:O′:N:N′)tricopper(I)(3 Cu—Cu)]

Compounds containing copper(I) are of interest for their role in biological processes. The nature of short (< ∼3.2 Å) Cu...Cu contacts within these compounds has been debated, being either described as weakly attractive (bonding) `cuprophilic' interactions, or simply as short metal–metal distances constrained by ligand geometry or largely ionic in nature. The title three‐dimensional Cu<sup>+</sup>‐containing coordination polymer, [Cu<sub>3</sub>(C<sub>7</sub>H<sub>7</sub>N<sub>2</sub>O<sub>2</sub>)Cl<sub>2</sub>]<sub>n</sub>, was formed from the in situ reduction of CuCl<sub>2</sub> in the presence of 3,5‐diaminobenzoic acid and KOH under hydrothermal conditions. Its complex crystal structure contains ten distinct Cu<sup>I</sup> atoms, two of which lie on crystallographic inversion centres. The copper coordination geometries include near‐linear CuOCl and CuN<sub>2</sub>, T‐shaped CuOCl<sub>2</sub> and distorted tetrahedral CuOCl<sub>3</sub> groups. Each Cu<sup>I</sup> atom is also associated with two adjacent metal atoms, with Cu...Cu distances varying from 2.7350 (14) to 3.2142 (13) Å; if all these are regarded as `cuprophilic' interactions, then infinite [01] zigzag chains of Cu^I atoms occur in the crystal. The structure is consolidated by N—H...Cl hydrogen bonds.     

Ion‐Directed Coordinative Polymerization of Copper(II) Pyridyl‐Alcohol Complexes Through Thiane Functionalities

A mononuclear complex [Cu(HL · S)₂(NO₃)₂] ( 1 ) and a one‐ dimensional coordination polymer [Cu(HL · S)Cl₂]_n ( 2 ) [HL · S = 4‐(pyridin‐2‐ylmethyl)tetrahydro‐2H‐thiopyran‐4‐ol] showcase the structure‐directing role of the counterions in their formation reaction: monodentate ligation of NO₃^– and Cl^– induces an octahedral (with two HL · S per Cu in 1 ) or trigonal‐bipyramidal (with one HL · S per Cu in 2 ) Cu^II coordination environment. In contrast to 1 exhibiting no coordinative metal–sulfur bonds in the crystal lattice (space group P2₁/c), 2 (P2₁/c) features intermolecular Cu–S contacts of 2.3188(7) Å. The coordination compounds are thermally stable up to ca. 160 °C. Whereas 1 demonstrates the spin‐like behavior of an isolated central Cu^II ion, compound 2 exhibits weak antiferromagnetic intra‐chain coupling with J ≈ –2.1 cm^–1 between neighboring Cu^II ions.     

One‐dimensional CuII coordination polymers containing C2h‐symmetric 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate linkers

Two new one‐dimensional Cu^II coordination polymers (CPs) containing the C_2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ⁴O,O′:O′′:O′′′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂]·H₂O}_n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ²O³:O^3′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂(H₂O)]·H₂O}_n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the Cu^II ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II).     

catena‐Poly[bis[(η2‐1‐allyl‐3‐aminopyridinium)copper(I)]‐di‐μ‐chloro‐copper(I)‐di‐μ‐chloro‐copper(I)‐di‐μ‐chloro]

Crystals of the title π‐complex, [Cu₄Cl₆(C₈H₁₁N₂)₂]_n, were obtained by means of alternating‐current electrochemical synthesis. The structure consists of infinite copper–chlorine chains to which 1‐allyl‐3‐amino­pyridinium moieties are attached via a η² Cu—(C=C) interaction. The two independent Cu atoms have distinct coordination environments. One is three‐coordinate, surrounded by two chloro ligands and the olefinic bond, whereas the second copper center is surrounded by a tetrahedral arrangement of four Cl atoms. The lower basicity of 3‐amino­pyridine as compared with 2‐ and 4‐amino­pyridine lowers the capacity of the organic ligand for donating to N—H⋯Cl hydrogen bonds and results in the formation of a large inorganic fragment.     

Rechargeable Room‐Temperature Na–CO2 Batteries

Developing rechargeable Na–CO₂ batteries is significant for energy conversion and utilization of CO₂. However, the reported batteries in pure CO₂ atmosphere are non‐rechargeable with limited discharge capacity of 200 mAh g^?1. Herein, we realized the rechargeability of a Na–CO₂ battery, with the proposed and demonstrated reversible reaction of 3 CO₂+4 Na?2 Na₂CO₃+C. The battery consists of a Na anode, an ether‐based electrolyte, and a designed cathode with electrolyte‐treated multi‐wall carbon nanotubes, and shows reversible capacity of 60000 mAh g^?1 at 1 A g^?1 (≈1000 Wh kg^?1) and runs for 200 cycles with controlled capacity of 2000 mAh g^?1 at charge voltage <3.7 V. The porous structure, high electro‐conductivity, and good wettability of electrolyte to cathode lead to reduced electrochemical polarization of the battery and further result in high performance. Our work provides an alternative approach towards clean recycling and utilization of CO₂.     

Ag@Au Core‐Shell Nanowires for Nearly 100 % CO2‐to‐CO Electroreduction

Electrochemical reduction of carbon dioxide (CO₂) to CO is regarded as an efficient method to utilize the greenhouse gas CO₂, because the CO product can be further converted into high value‐added chemicals via the Fisher–Tropsch process. Among all electrocatalysts used for CO₂‐to‐CO reduction, Au‐based catalysts have been demonstrated to possess high selectivity, but their precious price limits their future large‐scale applications. Thus, simultaneously achieving high selectivity and reasonable price is of great importance for the development of Au‐based catalysts. Here, we report Ag@Au core–shell nanowires as electrocatalyst for CO₂ reduction, in which a nanometer‐thick Au film is uniformly deposited on the core Ag nanowire. Importantly, the Ag@Au catalyst with a relative low Au content can drive CO generation with nearly 100 % Faraday efficiency in 0.1 m KCl electrolyte at an overpotential of ca. ?1.0 V. This high selectivity of CO₂ reduction could be attributed to a suitable adsorption strength for the key intermediate on Au film together with the synergistic effects between the Au shell and Ag core and the strong interaction between CO₂ and Cl^? ions in the electrolyte, which may further pave the way for the development of high‐efficiency electrocatalysts for CO₂ reduction.     

Ionothermal synthesis and crystal structure of a new organic–inorganic hybrid compound: catena‐poly[bis(1‐ethyl‐3‐methylimidazolium) [hepta‐μ‐bromido‐pentacuprate(I)]]

A new organic–inorganic hybrid compound, catena‐poly[bis(1‐ethyl‐3‐methylimidazolium) [μ₅‐bromido‐tri‐μ₃‐bromido‐tri‐μ₂‐bromido‐pentacuprate(I)]], {(C₆H₁₁N₂)₂[Cu₅Br₇]}_n, has been obtained under ionothermal conditions from a reaction mixture containing Ba(OH)₂·8H₂O, Cu(OH)₂·2H₂O, As₂O₅, 1‐ethyl‐3‐methylimidazolium bromide and distilled water. The crystal structure consists of complex [Cu₅Br₇]²⁻ anions arranged in sinusoidal {[Cu₅Br₇]²⁻}_n chains running along the a axis, which are surrounded by 1‐ethyl‐3‐methylimidazolium cations. Three of the five unique Br atoms and one of the three Cu^I atoms occupy special positions with half‐occupancy (a mirror plane perpendicular to the b axis, site symmetry m). The Cu^I ions are in a distorted tetrahedral coordination environment, with four Br atoms at distances ranging from 2.3667 (10) to 2.6197 (13) Å, and an outlier at 3.0283 (12) Å, exceptionally elongated and with a small contribution to the bond‐valence sum of only 6.7%. Short C—H...Br contacts build up a three‐dimensional network. The Cu...Cu distances within the chain range from 2.8390 (12) to 3.0805 (17) Å, indicating the existence of weak Cu^I...Cu^I cuprophilic interactions.     

A Polyhedron‐based Metal‐Organic Framework showing high CO2 Adsorption Capacity

A novel porous copper‐based metal‐organic framework {[Cu₂(TTDA)₂]*(DMA)₇}_n ( 1 ) (DMA = N,N‐dimethylacetamide) was designed and synthesized via the combination of a dual‐functional organic linker 5′‐(4‐(4H‐1,2,4‐triazol‐4‐yl)phenyl)‐[1,1′:3′,1′′‐terphenyl]‐4,4′′‐dicarboxylic acid (H₂TTDA) and a dinuclear Cu^II paddle‐wheel cluster. This MOF is characterized by elemental analysis, powder X‐ray diffraction (PXRD), thermo gravimetric analysis (TGA), and single‐crystal X‐ray diffraction. The framework is constructed from two types of cages (octahedral and cuboctahedral cages) and exhibits two types of circular‐shaped channels of approximate size of 5.8 and 11.4 Å along the crystallographic c axis. The gas sorption experiments indicate that it possesses a large surface area (1687 m² · g^–1) and high CO₂ adsorption capacities around room temperature (up to 172 cm³ · g^–1 at 273 K and 124 cm³ · g^–1 at 298 K).