Melt-quenched glass formation of a family of metal-carboxylate frameworks.

Metal-organic framework (MOF) glasses are an emerging class of glasses which complement traditional inorganic, organic and metallic counterparts due to their hybrid nature. Although a few zeolitic imidazolate frameworks have been made into glasses, how to melt and quench the largest subclass of MOFs, metal carboxylate frameworks, into glasses remains challenging. Here, we develop a strategy by grafting the zwitterions on the carboxylate ligands and incorporating organic acids in the framework channels to enable the glass formation. The charge delocalization of zwitterion-acid subsystem and the densely filled channels facilitate the coordination bonding mismatch and thus reduce the melting temperature. Following melt-quenching realizes the glass formation of a family of carboxylate MOFs (UiO-67, UiO-68 and DUT-5), which are usually believed to be un-meltable. Our work opens up an avenue for melt-quenching porous molecular solids into glasses.

MOF-supported crystalline ionic liquid: new type of solid electrolyte for enhanced and high ionic conductivity.

Solid-state electrolyte (SSE) is crucial for a high-performance all-solid-state battery. Here, a new solid sodium electrolyte based on the ionic liquid EIMS-NaTFSI and one metal-organic framework (MOF) UiO-67-MIMS functionalized with zwitterion groups MIMS was obtained (UiO-67 and was assembled with 4,4'-biphenyldicarboxylate linker and cluster Zr6O4(OH)4) (EIMS = 1-(1-ethyl-3-imidazolio)propane-3-sulfonate, NaTFSI = sodium bis(trifluoromethanesulfonyl)imide, MIMS = 1-(1-mthyl-3-imidazolio)propane-3-sulfonate). By contacting and pairing EIMS-NaTFSI (abbreviated as EN-1) to the MIMS group on the framework, EN-1 was directed and arranged along the channels within UiO-67-MIMS, forming a solid composite EN-1@UiO-67-MIMS with Bragg scatter, i.e., a crystalline ionic liquid containing Na+ salts (NaTFSI). Such an ionic liquid EN-1@UiO-67-MIMS bearing crystalline MOF matrix showed and preserved fast ion conduction (1.02 × 10-2 S cm-1) at 150 °C even after 30 days, and exhibited 1-2 orders of magnitude higher conductivities than the bulk ionic liquid EN-1 within a wide temperature range, although the ion content in the latter was higher. The infinite pathway paved by the EN-1 arranged and contacted the MIMS along the channels within MOF well accounts for the fast ion transmission and the stability of the solid-state electrolyte. Such MOF-based crystalline ionic liquid provides a new strategy for developing high-performance solid-state electrolytes for ions.

Facile Strategy for Efficient Charge Separation and High Photoactivity of Mixed-Linker MOFs.

Two new sets of UiO-Zr metal-organic framework (MOF) bearing mixed linkers BDC-(SCH3)2 and BDC-(SOCH3)2 that have different band gaps and edges were prepared through post oxidation and direct methods, namely, UiO-66-(SCH3)2-xh (x = 4, 9, 12 oxidation hours) and UiO-66-(SOCH3)x(SCH3)2-x (x = 0, 0.4, 0.6, 2), respectively. These composites with stoichiometric components were fully characterized via proton nuclear magnetic resonance (1H NMR) spectroscopy, powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), Fourier-transform infrared (FT-IR) spectra, Brunauer-Emmett-Teller (BET), photo electrochemical measurements, and femtosecond transient absorption (fs-TA) spectroscopy. The structure, electronic property, and photoresponsive and catalytic ability as the functions of the molar ratio of linkers and the synthetic protocol were first investigated. The mixed-linker UiO-66-(SCH3)2-xh and UiO-66-(SOCH3)x(SCH3)2-x exhibited improved performances as compared to the UiO-66-(SCH3)2 and UiO-66-(SOCH3)2 possessing neat linkers only. Their photo response and catalytic activity varied with different linker ratios. For UiO-66-(SCH3)2-xh, the performance increased with the increasing linker BDC-(SOCH3)2 ratio upon oxidation but reached the highest as the BDC-(SOCH3)2 being of 24.4% in UiO-66-(SCH3)2-9h. In comparison, the best photocurrent (80.74 uA/cm-2) and the highest H2 generation rate (2018.8 µmol g-1 h-1) (λ > 400 nm) in UiO-66-(SCH3)2-9h are about twice those of UiO-66-(SOCH3)0.4(SCH3)1.6 obtained by direct synthesis, although the linker BDC-(SOCH3)2 ratio of those two composites is almost the same (24.4% vs 23.9%). Recorded shorter lifetime and higher charge separation efficiency of the former than those of the latter suggest the postsynthetic protocol as the efficient method for achieving the mixed-liner-MOF-based photocatalyst with high performance. A new type-II tailored homojunction is proposed in these mixed-linker MOFs for their efficient charge separation and improved activity.

A Homoleptic Alkynyl-Ligated [Au13 Ag16 L24 ]3- Cluster as a Catalytically Active Eight-Electron Superatom.

A new alkynylated cluster [Au13 Ag16 (C10 H6 NO)24 ]3- is prepared by a NaBH4 mediated reduction method. The AuAg clusters are confirmed by sophisticated characterization techniques. It has a unique "Aucenter @Ag12 @Au12 Ag4 " metal framework which is protected by 24 atypical alkyne ligands L (L=C10 H6 NO). The ligands construct a unique type of motif L-(Ag)-Au-(Ag)-L at the cluster interface, where the alkyne (C≡C) group of each L was linked by sharing an Au atom through the σ bonds and each C≡C group was discretely connected to a chemically different Ag atom (Agicosahedral /Agcap ) through π bonds. The electronic and optical properties of [Au13 Ag16 L24 ]3- were studied. DFT characterized the cluster as a clear 8-electron superatom, and peaks in the optical absorption spectrum were interpreted in terms of the P and D superatom states. The supported Au13 Ag16 L24 /CeO2 catalyst exhibited high catalytic activity and selectivity towards the A3 -coupling reaction involving benzaldehyde, diethylamine, and phenylacetylene.

MOF-Directed Synthesis of Crystalline Ionic Liquids with Enhanced Proton Conduction.

Arranging ionic liquids (ILs) with long-range order can not only enhance their performance in a desired application, but can also help elucidate the vital between structure and properties. However, this is still a challenge and no example has been reported to date. Herein, we report a feasible strategy to achieve a crystalline IL via coordination self-assembly based reticular chemistry. IL1 MOF, was prepared by designing an IL bridging ligand and then connecting them with metal clusters. IL1 MOF has a unique structure, where the IL ligands are arranged on a long-range ordered framework but have a labile ionic center. This structure enables IL1 MOF to break through the typical limitation where the solid ILs have lower proton conductivity than their counterpart bulk ILs. IL1 MOF shows 2-4 orders of magnitude higher proton conductivity than its counterpart IL monomer across a wide temperature range. Moreover, by confining the IL within ultramicropores (<1 nm), IL1 MOF suppresses the liquid-solid phase transition temperatures to lower than -150 °C, allowing it to function with high conductivity in a subzero temperature range.

A Methylthio-Functionalized-MOF Photocatalyst with High Performance for Visible-Light-Driven H2 Evolution.

Recently, the emergence of photoactive metal-organic frameworks (MOFs) has given great prospects for their applications as photocatalytic materials in visible-light-driven hydrogen evolution. Herein, a highly photoactive visible-light-driven material for H2 evolution was prepared by introducing methylthio terephthalate into a MOF lattice via solvent-assisted ligand-exchange method. Accordingly, a first methylthio-functionalized porous MOF decorated with Pt co-catalyst for efficient photocatalytic H2 evolution was achieved, which exhibited a high quantum yield (8.90 %) at 420 nm by use sacrificial triethanolamine. This hybrid material exhibited perfect H2 production rate as high as 3814.0 µmol g-1 h-1 , which even is one order of magnitude higher than that of the state-of-the-art Pt/MOF photocatalyst derived from aminoterephthalate.

A route to robust thioether-functionalized MOF solid materials displaying heavy metal uptake and the ability to be further oxidized.

Here we developed a facile solvent-assisted ligand exchange method for synthesizing thioether-containing hybrid metal-organic frameworks (MOFs) that cannot be made using direct synthesis. Such a tailored approach provides an alternative method to achieve thioether-based MOFs and its oxidation-decorated materials. These materials showed the ability to take up heavy metals from solution and the ability to capture CO2.

Synthesis, crystal structures and antitumor activity of two platinum(II) complexes with methyl hydrazinecarbodithioate derivatives of indolin-2-one.

Two new platinum(II) complexes 7a and 7b with methyl hydrazinecarbodithioate derivatives of indolin-2-one have been prepared and characterized by single-crystal X-ray diffraction, NMR spectroscopy and mass spectrometry. Antiproliferative activity of the two complexes and their ligands 6a and 6b against HCT-116, MCF-7 and MDA-MB-231 cell lines was determined by the MTS assay. Complexes 7a and 7b exhibited stronger antiproliferative activity against three cell lines than compounds 6a and 6b (IC50, 1.89-5.60 versus 6.52-35.13 µM). Moreover, treatment of HCT-116 cells with the complexes resulted in an obvious sub-G1 peak by cell cycle profile analysis, and an increase of cleaved PARP1 and caspases 3, 7, and 9 by immunoblotting analysis. Live cell imaging showed that nucleus shrinkage and condensation started to appear when MCF-7 cells were treated with 7a for 8 h. Fluorescent spectrophotometric analysis revealed that the complexes physically associated with calf thymus DNA. Competitive DNA binding assays uncovered that the complexes non-covalently bind to DNA. Taken together, our results indicated that the two new platinum(II) complexes 7a and 7b non-covalently bind to DNA with high affinity and exhibit cytotoxicity against cancer cells by inducing apoptosis.

A Metal-Organic Framework Impregnated with a Binary Ionic Liquid for Safe Proton Conduction above 100 °C.

To develop proton-conducting materials under low-humidity conditions and at moderate working temperature still remains challenging for fuel-cell technology. Here, a new type of proton-conducting material, EIMS-HTFSA@MIL, which was prepared by impregnating the binary ionic liquid, EIMS-HTFSA (EIMS=1-(1-ethyl-3-imidazolium)propane-3-sulfonate; HTFSA=N,N-bis(trifluoromethanesulfonyl)amide), into a mesoporous metal-organic framework, MIL-101 ([Cr3 F(H2 O)2 O(BDC)3 ⋅n H2 O] (n≈0.25, BDC=1,4-benzenedicarboxylate)) is reported. By taking advantage of the ionic-liquid properties, such as high thermal stability, non-volatility, non-flammability, and low corrosivity, EIMS-HTFSA@MIL shows potential application as a safe electrolyte in proton conduction above 100 °C.

A stepwise bulk-to-cluster-to-particle transformation toward the efficient synthesis of alkynyl-protected silver nanoclusters.

We report herein the efficient synthesis of alkynyl-protected silver nanoclusters in terms of macrocycle-assisted bulk-to-cluster-to-nanoparticle transformation. Different substituted phenylacetylide ligands are applied to stabilize the silver nanoclusters by metal-carbon bonds and meanwhile determine the size of silver nanoclusters.

High-nuclearity silver(I) cluster-based coordination polymers assembled with multidentate oligo-α-heteroarylsulfanyl ligands.

Two novel coordination polymers [Ag16(SO4)8][Ag4(SO4)2]3(L1)12·nH2O (n = 72) (1) and [Ag10(SO4)5(L2)4(H2O)2]·8H2O (2) based on conformationally variable oligo-α-heteroarylsulfanyl ligands 2-(pyrazin-2-ylthio)-6-(pyridin-2-ylthio)pyrazine (L1) or 2,6-bis(pyrazin-2-ylthio)pyrazine (L2) and sulfate-templated high-nuclearity Ag(I) clusters as structure-building units (SBUs) have been synthesized under mild conditions. Single-crystal X-ray analysis showed that complex 1 exhibits a porous three-dimensional framework containing Ag16(SO4)8 and Ag4(SO4)2 SBUs that are interconnected by L1 ligands, whereas 2 has a much denser network constructed from Ag10(SO4)5 SBUs and L2 linkers. To our knowledge, the Ag16(SO4)8 cluster core found in 1 is the largest sulfate-based polynuclear SBU in coordination polymers, and the 14-connected Ag10(SO4)5 in 2 is the highest-connectivity Ag(I) cluster SBU reported to date. These two complexes were fully characterized by infrared spectroscopy, elemental analysis, powder X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry.

2,2'-Sulfonyl-dipyrazine 4-oxide.

In the title compound, C(8)H(6)N(4)O(3)S, the dihedral angle between the pyrazine rings is 85.04 (1)°. In the crystal, mol-ecules are arranged along the a axis and are linked by C-H⋯N hydrogen bonds and pyrazine-pyrazine π-π inter-actions [centroid-centroid distance = 3.800 (1) Å, forming an infinite chain array. The chains are connected by C-H⋯O(oxide) hydrogen bonds into layers lying parallel to the ab plane. Along the c axis, the layers are stacked and linked through C-H⋯O(sulfon-yl) inter-actions, forming a three-dimensional network.

3,3'-Carbonyl-dipyridinium bis-(perchlorate).

In the title molecular salt, C(11)H(10)N(2)O(2+)·2ClO(4) (-), the complete cation is generated by crystallographic twofold symmetry. The dihedral angle between the pyridyl rings is 67.07 (7)°. The crystal structure features N-H⋯Cl hydrogen bonds, forming sheets in the ab plane.

Supramolecular framework in catena-poly[[(nitrato-κO)silver(I)]-µ-(R,S)-2-(pyridin-4-ylsulfinyl)pyrimidine-κ3N,O:N'].

In the title complex, [Ag(NO(3))(C(9)H(7)N(3)OS)](n), η(1):η(1):η(1):µ(2)-bridging 2-(pyridin-4-ylsulfinyl)pyrimidine (pypmSO) ligands with opposite chiralities are alternately arranged to link the Ag(I) cations through two N atoms and one sulfinyl O atom of each ligand, leading to an extended zigzag coordination chain structure along the [ ̅201] direction. An FT-IR spectroscopic study shows a decreased stretching frequency for the η(1)-O-bonded S=O group compared with that of the free ligand. The parallel chains are arranged and interconnected via O(S=O)···π(pyridine/pyrimidine) and C-H(pyridine)···O(NO(3)(-)) interactions to furnish a layer almost parallel to the ac plane. Along the b axis, the layers are stacked and stabilized through anion(NO(3)(-))···π(pyrimidine) interactions to form a three-dimensional supramolecular framework. The ligand behaviour of the new diheterocyclic sulfoxide and the unconventional O(S=O)···π(pyridine/pyrimidine) and anion(NO(3)(-))...π(pyrimidine) interactions in the supramolecular assembly of the title complex are presented.

5-Fluoro-1-(4-meth-oxy-benz-yl)indoline-2,3-dione.

In the title compound, C(16)H(12)FNO(3), the dihedral angle between the benzene ring and the plane of the indole ring system is 71.60 (6)°. In the crystal, mol-ecules stack along the b axis through π-π inter-actions between the adjacent indole-2,3-dione units with a centroid-centroid distance of 3.649 (3) Å. Inter-molecular C-H⋯O=C and C-H⋯π inter-actions further stabilize the structure, forming a three-dimensional framework.

3,3-Dichloro-1-(chloro-meth-yl)indolin-2-one.

In the title compound, C(9)H(6)Cl(3)NO, the pyrrole ring is almost coplanar with the benzene ring [dihedral angle = 1.90 (9)°], while the Cl-C-N-C torsion angle is 98.78 (17)°. In the crystal, pairs of mol-ecules are inter-connected by pairs of Cl⋯Cl inter-actions [3.564 (5) Å], forming dimers, which are further peripherally connected through inter-molecular C-H⋯O=C and π-π inter-actions [centroid-centroid distances = 4.134 (7), 4.134 (6) and 4.238 (7) Å], forming a two-dimensional network.

catena-Poly[[aqua-cadmium(II)]-bis-(µ(2)-4-chloro-benzoato)].

In the title complex, [Cd(C(7)H(4)ClO(2))(2)(H(2)O)](n), the Cd atom lies on a twofold axis and adopts a square-pyramidal coordination geometry. The water mol-ecule occupies the axial site with O atoms from four different 4-chloro-benzoato ligands in the equatorial plane. Pairs of 4-chloro-benzoato ligands bridge adjacent Cd(II) ions, generating an infinite chain structure along the c axis. Parallel polymeric chains are further inter-connected through water-acetate O-H⋯O hydrogen bonds, forming layers in the bc plane.

Bis[5-(2-pyrid-yl)pyrazine-2-carbonitrile]-silver(I) tetra-fluorido-borate.

In the title mononuclear complex, [Ag(C(10)H(6)N(4))(2)]BF(4), the Ag(I) atom adopts a square-planar N(4 )coordination geometry and is surrounded by two 5-(2-pyrid-yl)pyrazine-2-carbonitrile ligands. The tetra-fluorido-borate anions link the mononuclear cations through inter-molecular C-H⋯F hydrogen-bonding inter-actions, forming an infinite tape structure along [110]. Other weak inter-actions occur: π-π stacking with centroid-centroid distances of 3.820 (2) and 3.898 (1) Šbetween pyridyl rings and 3.610 (2) and 3.926 (2) Šbetween pyrazinyl rings as well as F⋯π contacts involving the tetra-fluorido-borate anions and pyrazine rings [F⋯centroid = 2.999 (3) Å]; these combine with the hydrogen-bonding inter-actions to link the mononuclear cations into a three-dimensional supra-molecular architecture.

Chlorido{N,N-dibenzyl-N,N-bis-[(diphenyl-phosphan-yl)meth-yl]pyridine-2,6-diamine}-methyl-platinum(II).

In the title mononuclear complex, [Pt(CH(3))Cl(C(45)H(41)N(3)P(2))], the pyridine-2,6-diamine ligand can be viewed as a centrosymmetric motif having two pendant N-benzyl-N-[(diphenyl-phosphan-yl)meth-yl] arms, the two P atoms of which chelate to the Pt(II) ion, forming a ten-membered metallocycle. A distorted square-planar coordination geometry around the Pt(II) atom is completed by a methyl ligand and a chloride ion. The packing between the mononuclear units is achieved through C-H⋯π inter-actions, which link the mol-ecules into chains along the c axis.

1,1'-(Ethane-1,2-di-yl)bis-(indoline-2,3-dione).

The mol-ecule of the title compound, C(18)H(12)N(2)O(4), is situated on a crystallographic centre of symmetry. The mol-ecule has a zigzag structure, with two parallel symmetry-related indoline-2,3-dione fragments linked by an ethyl-ene group at each N atom. In the crystal, the mol-ecules stack in columns along the b axis. There are two such columns in the structure. The mol-ecules within each column are parallel; however, the mol-ecules in the two columns differ in the respective orientation of the indoline-2,3-dione fragments. In one column, they are approximately parallel to (112), while in the other they are approximately parallel to (12). The inter-planar angle between the indoline-2,3-dione fragments in the two columns is 80.83 (3)°. The mol-ecules within each column are related by mutual displacement of their centres of symmetry, that is (0, ±1/2, ±1/2). The packing between the mol-ecules is provided by weak inter-actions only, viz. C-H⋯O hydrogen bonds and π-π [centroid-centroid distance = 3.8745 (8) Å] and C=O⋯π inter-actions.