MOF-Based Solid-State Proton Conductors Obtained by Intertwining Protic Ionic Liquid Polymers with MIL-101.

Solid-state proton conductors based on the use of metal-organic framework (MOF) materials as proton exchange membranes are being investigated as alternatives to the current state of the art. This study reports a new family of proton conductors based on MIL-101 and protic ionic liquid polymers (PILPs) containing different anions. By first installing protic ionic liquid (PIL) monomers inside the hierarchical pores of a highly stable MOF, MIL-101, then carrying out polymerization in situ, a series of PILP@MIL-101 composites was synthesized. The resulting PILP@MIL-101 composites not only maintain the nanoporous cavities and water stability of MIL-101, but the intertwined PILPs provide a number of opportunities for much-improved proton transport compared to MIL-101. The PILP@MIL-101 composite with HSO4 - anions shows superprotonic conductivity (6.3 × 10-2  S cm-1 ) at 85 °C and 98% relative humidity. The mechanism of proton conduction is proposed. In addition, the structures of the PIL monomers were determined by single crystal X-ray analysis, which reveals many strong hydrogen bonding interactions with O/NH···O distances below 2.6 Å.

2D Zn-Porphyrin-Based Co(II)-MOF with 2-Methylimidazole Sitting Axially on the Paddle-Wheel Units: An Efficient Electrochemiluminescence Bioassay for SARS-CoV-2.

High electrocatalytic activity with tunable luminescence is crucial for the development of electrochemiluminescence (ECL) luminophores. In this study, a porphyrin-based heterobimetallic 2D metal organic framework (MOF), [(ZnTCPP)Co2(MeIm)] (1), is successfully self-assembled from the zinc(II) tetrakis(4-carboxyphenyl)porphine (ZnTCPP) linker and cobalt(II) ions in the presence of 2-methylimidazole (MeIm) by a facile one-pot reaction in methanol at room temperature. On the basis of the experimental results and the theoretical calculations, the MOF 1 contains paddle-wheel [Co2(-CO2)4] secondary building units (SBUs) axially coordinated by a MeIm ligand, which is very beneficial to the electron transfer between the Co(II) ions and oxygen. Combining the photosensitizers ZnTCPP and the electroactive [Co2(-CO2)4] SBUs, the 2D MOF 1 possesses an excellent ECL performance, and can be used as a novel ECL probe for rapid nonamplified detection of the RdRp gene of SARS-CoV-2 with an extremely low limit of detection (≈30 aM).

The Chemistry of the Passivation Mechanism of Perovskite Films with Ionic Liquids.

Passivation of perovskite films by ionic liquids (ILs) improves the performance (efficiency and stability) of perovskite solar cells (PSCs). However, the role of ILs in the passivation of perovskite films is not fully understood. Here, we report the reactions of commonly used ILs with the components of perovskites. The reaction of ILs with perovskite precursors (PbI2 and methylammonium iodide or formamidinium iodide) in a 1:1:1 molar ratio affords one-dimensional (1D) salts composed of the IL cation interspersed along infinite 1D polymeric [PbI3]-n chains. If the IL is applied in excess, the resulting crystal is composed of six cations surrounding a discrete [Pb3I12]6- cluster. All the isolated salts were unambiguously characterized by single-crystal X-ray diffraction analysis, which also reveals extensive hydrogen-bonding interactions.

An Unprecedented Bird Nest Molybdenum(V) Cobalto-Phosphate Nanosized Wheel Constructed from the [H55 (Mo24 O48 )(Co4 O)2 Co16 (PO4 )42 (py)6 (EtOH)2 (H2 O)11 ]3- Anion.

An unprecedented bird-nest high-nuclear molybdenum(V) cobalto-phosphate nanosized wheel modified by imidazole (im) and pyridine (py), {[H55 (Mo24 O48 )(Co4 O)2 Co16 (PO4 )42 (py)6 (EtOH)2 (H2 O)11 ]- @[(Him)2 (Hpy)]}(N-Et-py)(H2 PO4 )(py)7 (EtOH)⋅12 H2 O (1), has been successfully synthesized by self-assembly. The anionic huge wheel consists of two rare {Co4 O} squares, four {Co4 } tetramers, four {Mo4 } tetramers and four {Mo2 } dimers, linked by bridging oxygen atoms and [PO4 ] groups and encloses two imidazolium cations and a protonated pyridium for charge balance. Surprisingly, 1 represents the first twisted wheel-shaped cluster with a record high-nuclear molybdenum(V) cobalto-phosphate. The delocalized electron effects of the cluster are enhanced with the help of coordinated py ligands, which endows 1 with an excellent third-order nonlinear optical (NLO) response. Additionally, 1 also shows a better photocatalytic water oxidation activity than Co(NO3 )2 with the O2 production of 205 µmol during 6 h in the absence of the [Ru(bpy)3 ]2+ photosensitizer.

Metal-Free Synthetic Shortcut to Octahydro-Dipyrroloquinoline Skeletons from 2,5-Cyclohexadienone Derivatives and l-Proline.

The tandem decarboxylative condensation-dimerization reaction of l-proline with 2,5-cyclohexadienones including p-quinone monoacetals, p-quinol ethers, and p-quinols is reported to provide a concise and rapid synthesis of octahydro-dipyrroloquinoline compounds. The reaction features the use of cost-effective and readily available starting materials, high efficiency, metal-free and green reaction conditions. The reaction is applied to the synthesis of incargranine B aglycone. The discovery of this reaction may suggest a biosynthetic pathway from 2,5-cyclohexadienones and proline for natural ingredients containing pyrroloquinoline moieties.

Creative Construction of a Series of Chiral 3D Indium-Organic Frameworks with a umy Topology.

Using 2,2'-R2-biphenyl-4,4'-dicarboxylic acid to bind with a cis-[InO4(µ2-OH)2] octahedron, three novel chiral 3D indium-organic frameworks, [In(µ2-OH)L] [1, L1, R = N(CH3)2; 2, L2, R = OCH3; 3, L3, R = CH3], have been hydrothermally synthesized without chiral reagents. Crystal structure analyses reveal that 1-3 show an unprecedented 4-connected umy topology with the Schläfli symbol (42·64). 1 exhibits high water stability and good sorption selectivity of CO2 over N2, while 3 displays high C2H2, C2H4, and C2H6 uptake capacity at 273 K.

A New Class of Metal-Cyclam-Based Zirconium Metal-Organic Frameworks for CO2 Adsorption and Chemical Fixation.

Metal-organic frameworks (MOFs) have shown great promise in catalysis, mainly due to their high content of active centers, large internal surface areas, tunable pore size, and versatile chemical functionalities. However, it is a challenge to rationally design and construct MOFs that can serve as highly stable and reusable heterogeneous catalysts. Here two new robust 3D porous metal-cyclam-based zirconium MOFs, denoted VPI-100 (Cu) and VPI-100 (Ni), have been prepared by a modulated synthetic strategy. The frameworks are assembled by eight-connected Zr6 clusters and metallocyclams as organic linkers. Importantly, the cyclam core has accessible axial coordination sites for guest interactions and maintains the electronic properties exhibited by the parent cyclam ring. The VPI-100 MOFs exhibit excellent chemical stability in various organic and aqueous solvents over a wide pH range and show high CO2 uptake capacity (up to ∼9.83 wt% adsorption at 273 K under 1 atm). Moreover, VPI-100 MOFs demonstrate some of the highest reported catalytic activity values (turnover frequency and conversion efficiency) among Zr-based MOFs for the chemical fixation of CO2 with epoxides, including sterically hindered epoxides. The MOFs, which bear dual catalytic sites (Zr and Cu/Ni), enable chemistry not possible with the cyclam ligand under the same conditions and can be used as recoverable stable heterogeneous catalysts without losing performance.

Electrostatic and non-covalent interactions in dicationic imidazolium-sulfonium salts with mixed anions.

A series of thioether-functionalised imidazolium salts have been prepared and characterized. Subsequent reaction of the thioether-functionalised imidazolium salts with iodomethane affords imidazolium-sulfonium salts composed of doubly charged cations and two different anions. Imidazolium-sulfonium salts containing a single anion type are obtained either by a solvent extraction method or by anion exchange. The imidazolium-sulfonium salts undergo a methyl-transfer reaction on exposure to water, giving rise to a new, singly charged imidazolium salt with iodide introduced at the 2-position of the imidazolium ring. Crystal structures of some of the imidazolium-sulfonium salts were determined by X-ray crystallography providing the topology of the interactions between the dications and the anions. Electrospray ionization mass spectrometry and quantum-chemical calculations were used to rationalise the relative strength of these interactions.

A novel dumbbell-like polyoxometalate assembled of copper(II)-disubstituted monovacant keggin polyoxoanions with a tetranuclear copper cluster.

A dimeric Keggin polyoxometalate, [Cu(bpy)(µ2-OH)]4[(H2O)(bpy)2HPW11Cu2O39]2·2CH3CH2OH·10H2O (1), constructed from two dicopper(II)-substituted monovacant Keggin polyoxoanions bridged by a Cu4 cluster, has been hydrothermally synthesized. Magnetic analysis indicates predominantly an antiferromagnetic interaction between copper(II) centers. Compound 1 also shows very high catalytic activity for the esterification of phosphoric acid with equimolar lauryl alcohol to monoalkyl phosphate ester.

Syntheses, crystal structures and intermolecular interactions of six novel pyrimidin-2-yl-substituted triaryltriazoles.

Six new pyrimidin-2-yl-substituted triaryltriazoles, namely, 4-(4-R-phenyl)-3-(pyridin-2-yl)-5-(pyrimidin-2-yl)-1,2,4-triazoles [L1: R = methoxy (OCH3); L2: R = methyl (CH3); L3: R = nil (H); L4: R = bromo (Br); L5: R = chloro (Cl); L6: R = fluoro (F)] have been successfully synthesized with yields in the range 68.3-81.7%. Compounds L1-6 have been characterized by UV-Vis, FT-IR, 1H NMR and ESI-MS spectroscopy, and elemental analysis. In addition, the structures of L2-6 and the ethanol monosolvate of L2 (L2·C2H5OH) have been determined by single-crystal X-ray diffraction. A combination of intermolecular O-H...N, C-H...O, C-H...N and C-H...π hydrogen bonds connects the components of L2·C2H5OH into a three-dimensional (3D) framework. A combination of three intermolecular C-H...N hydrogen bonds links the molecules of L2 or L3 into two different 3D networks. Both L4 and L5 show a similar 3D net structure through two intermolecular C-H...N hydrogen bonds and one kind of C-H...π interaction. However, L6 displays a more complicated 3D net structure via three intermolecular C-H...N hydrogen bonds and one kind of C-H...π interaction. Notably, an interaction between the π-electrons and the lone-pair p-electrons of a halogen atom (Br, Cl and F) is observed in L4-6, which will further stabilize the 3D networks. The intermolecular interactions in L2·C2H5OH and L2-6 were further investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to show that the prominent interactions are H...H, N...H/H...N and C...H/H...C contacts.

(C4N2H12)3[Ln3(OH)(SO4)7] (Ln = Sm, Eu, and Tb): a series of honeycomb-like open-framework lanthanide sulfates with extra-large channels containing 24-membered rings.

Three novel organic amine templated honeycomb-like lanthanide sulfates, (C4N2H12)3[Ln3(OH)(SO4)7] (Ln = Sm (1), Eu (2), and Tb (3)), with extra-large channels containing 24-membered rings (24MR) have been synthesized by using chair form piperazine as the structure-directing agent under one-pot solvothermal reactions. The three compounds are isostructural, and the open framework of the title compounds is the first lanthanide sulfate example with extra-large channels containing 24MR. It has an acs framework topology. The three compounds are strong luminescent materials that display characteristic Sm(3+), Eu(3+), and Tb(3+) emission bands in the visible region. The observed second-harmonic generation efficiencies of the three compounds are all 0.4 times that of urea. TGA profiles and XRD measurements demonstrate their high thermal stability.

Synthesis and study of three novel macrocyclic selena[n]ferrocenophanes containing a naphthalene unit.

Three novel macrocyclic ligands, L1-L3, in which a ferrocene unit and a fluorescent moiety are linked to polyselena rings have been designed and prepared from 1,1'-bis(3-bromopropylseleno)ferrocene. Reaction of L with [M(NCMe)4](PF6)2 (M = Pd and Pt) led to complexes [ML](PF6)2 (M = Pd and Pt). Crystal structure analysis revealed that after complexation, the macrocyclic ligand adopts the unusual c,c,c conformation due to intramolecular C-H···π interactions from the hydrogen atoms of ferrocene moieties to the naphthalene ring. Electrochemical studies showed that in [ML](PF6)2 (M = Pd and Pt) the half-wave potential of the 1,1'-ferrocenediyl group shifts to much more positive potentials due to electron density withdrawn from Se donor atoms. Electrochemical and optical measurements were used to calculate HOMO and LUMO levels as well as HOMO-LUMO band gaps. Results were compared and correlated with the differences in molecular structures.

Cu-catalyzed direct C-H bond functionalization: a regioselective protocol to 5-aryl thiazolo[3,2-b]-1,2,4-triazoles.

An efficient, regioselective C-5 arylation of thiazolo[3,2-b]-1,2,4-triazoles catalyzed by a simple copper catalyst was developed. This arylation proceeded smoothly and tolerated a variety of functional groups (44 examples). A wide range of functionalized thiazolo[3,2-b]-1,2,4-triazole derivatives were obtained in high yields (up to 99% yield). Possible catalytic cycles of the arylation were also discussed.

A new "fully reduced" polyoxovanadate constructed from nanosized triangle-shaped [V(III)3V(IV)18P6O60(DACH)3]}9- cluster anions exhibiting ferrimagnetic interactions.

Magnetic personality: A pentavalent vanadium source was employed to prepare the largest highly reduced polyoxovanadate cluster by virtue of the reducing power of 1,2-diaminocyclohexane under hydrothermal conditions. The new non-classical triangle-shaped cluster shows good catalytic selectivity for the oxidation of styrene and exhibits ferrimagnetic interactions that could make it a promising magnetic material.

L- and D-[Ln(HCO2)(SO4)(H2O)](n) (Ln = La, Ce, Pr, Nd, and Eu): chiral enantiomerically 3D architectures constructed by double -[Ln-O](n)- helices.

A total of 10 three-dimensional chiral coordination compounds L- and D-[Ln(HCO(2))(SO(4))(H(2)O)](n) (Ln = La, Ce, Pr, Nd, and Eu) have been synthesized without any chiral auxiliary and characterized by IR, thermogravimetric, and elemental analyses. Their structures were determined by single-crystal X-ray structural analysis, which shows that L-[Ln(HCO(2))(SO(4))(H(2)O)](n) (Ln = La, Ce, Pr, Nd, and Eu) crystallize in space group P4(3) and are laevogyrate and isostructural. The chiral frameworks of L-[Ln(HCO(2))(SO(4))(H(2)O)](n) are constructed from L-helical Ln-O cluster chains, while adjacent L-type helical -[Ln-O](n)- chains are connected through O-Ln-O linkages to form chiral intertwined Ln-O double helices of left-handedness. D-[Ln(HCO(2))(SO(4))(H(2)O)](n) crystallize in space group P4(1), and their chiral frameworks consist of D-helical Ln-O cluster chains. The observed second-harmonic-generation efficiencies of [La(HCO(2))(SO(4))(H(2)O)](n), Ce(HCO(2))(SO(4))(H(2)O)](n), [Pr(HCO(2))(SO(4))(H(2)O)](n), [Nd(HCO(2))(SO(4))(H(2)O)](n), and [Eu(HCO(2))(SO(4))(H(2)O)](n) are 0.7, 0.8, 0.7, 0.5, and 0.7 times that of urea, respectively. It is particularly interesting that [Pr(HCO(2))(SO(4))(H(2)O)](n) shows good two-photon absorption.

2-(2,4-Difluoro-phen-yl)-5-nitro-pyridine.

In the title mol-ecule, C(11)H(6)F(2)N(2)O(2), the benzene and pyridine rings form a dihedral angle of 32.57 (6)°. The nitro group is tilted with respect to the pyridine ring by 12.26 (9)°. An intra-molecular C-H⋯F hydrogen bond is present. In the crystal, mol-ecules inter-act through π-π stacking inter-actions [centroid-centroid distances = 3.7457 (14) Å], forming columnar arrangements along the b axis. The crystal packing is further enforced by inter-molecular C-H⋯O and C-H⋯N hydrogen bonds.

[6,13-Bis(2,4-dichloro-benzo-yl)-5,7,12,14-tetra-methyl-dibenzo[b,i][1,4,8,11]tetra-aza-cyclo-tetra-decinato- κ4N]nickel(II) acetone monosolvate.

In the title complex, [Ni(C36H26Cl4N4O2)]·C3H6O, two 2,4-dichloro-benzoyl groups are grafted onto the methine groups of the Ni(II) complex Ni(tmtaa) (H2tmtaa = 5,7,12,14-tetra-methyl-4,11-dihydro-dibenzo[b,i][1,4,8,11]tetra-aza-cyclo-tetra-decine). The complex has the shape of a saddle. The Ni atom is tetra-coordinated by the four N atoms of the macrocycle, forming a slightly tetra-hedrally distorted square-planar geometry. The metal is displaced by 0.0101 (8) Šfrom the N4 mean plane. The aromatic rings of the 2,4-dichloro-benzoyl groups form dihedral angles of 87.1 (2) and 82.1 (2)° with the N4 mean plane.

3-{[Bis(pyridin-2-ylmeth-yl)amino]-meth-yl}-2-hy-droxy-5-methyl-benz-aldehyde.

In the title compound, C(21)H(21)N(3)O(2), the pyridine rings and the benzene ring lie in a propeller arrangement around the central tertiary amine N atom. The dihedral angles formed by the benzene ring with the pyridine rings are 61.0 (3) and 49.6 (3)°, while the dihedral angle between the pyridine rings is 69.7 (3)°. The mol-ecular conformation is stabilized by intramolecular bifurcated O-H⋯N hydrogen bonds. In the crystal, inversion dimers are formed via pairs of C-H⋯N hydrogen bonds.

Sandwich-Structured Carbon Paper/Metal-Organic Framework Monoliths for Flexible Solar-Powered Atmospheric Water Harvesting On Demand.

Solar-powered atmospheric water harvesting (AWH) with metal-organic frameworks (MOFs) has been recognized as an attractive way to alleviate water shortage stress in rural arid areas given the naturally abundant solar energy. However, the existing solar-powered AWH technologies only allow a singular water production mode: either solar heating-driven AWH which usually results in rather poor water productivity due to the limited availability of sufficient sunlight or conductive heating-driven all-day AWH with significantly improved water productivity but requiring additional electricity provided with a photovoltaic module. This greatly limits the flexibility in managing AWH based on climate conditions, water productivity, and energy cost. Herein, a sandwich-structured MOF monolith (denoted as CACS) with dual heating capacity, localized solar heating (LSH) and electrical heating (LEH), is presented. Compared with LSH, the use of LEH leads to more rapid and uniform heating of CACS monoliths, thereby driving a significantly enhanced water desorption efficiency with faster kinetics. Using the CACS monolith as an AWH sorbent, a new type of atmospheric water harvester is developed and able to produce water in multiple working modes: LSH-, LEH-, and LSH-/LEH-driven AWH, thereby enabling flexible AWH on demand: direct use of sunlight for LSH-driven AWH during the sunlight-sufficient day and/or LEH-driven all-day AWH powered by a photovoltaic module particularly during the sunlight-absent/-insufficient time (night or cloudy day). When working at the LSH-/LEH-driven AWH mode, the resulting prototype delivers 1.4 LH2O kgMOF-1 day-1 of water productivity with 2.3 kW·h L-1H2O of energy consumption, corresponding to 5.4 times higher water productivity than the LSH-driven AWH working mode alone and 17.9% of energy saving at the cost of 22.2% of water productivity reduction compared with the LEH-driven AWH working mode alone. The current work, therefore, demonstrates a novel solar-powered AWH strategy that enables all-day water production with flexible choices on AWH working modes in terms of climate conditions, desired water productivity, and energy cost.

Schiff Base Complexes with Covalently Anchored Luminophores: Self-Enhanced Electrochemiluminescence Detection of Neomycin.

A novel electrochemiluminescence (ECL) amplification strategy was established aiming to overcome the inherent shortcomings of the current oxygen (O2) coreactant ECL systems. Macrocyclic Schiff base Fe complexes were rationally designed as a novel integrated ECL emitter by iminium linkage between N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and 1,10-phenanthroline-2,9-dicarbaldehyde (PDL) and postmetalation of the macrocyclic Schiff base. Covalently combining luminophore ABEI with a catalytic center endowed the novel ECL emitter with both remarkable redox electrocatalytic properties and significantly enhanced ECL efficiency. The high content of ferrous iron and the dominantly active low-spin Fe state greatly contributed to the inherent catalytic activity for O2 activation. The rational modification of luminophore optimized the spatial distribution and simultaneously shortened the species transport distance of coreactant radicals generated in situ from dissolved O2, resulting in significantly self-enhanced ECL efficiency. Neomycin, which posed a growing threat to aquatic biodiversity and environmental safety, as the model antibiotic was successfully detected with a detection limit of 0.21 pM (S/N = 3), clarifying a promising application prospect of this new luminophore-embedded ECL amplification strategy in biological analysis and environmental monitoring.