Suite of Organoplatinum(II) Triangular Metallaprism: Aggregation-Induced Emission and Coordination Sequence Induced Emission Tuning.

A series of triangular metallaprisms with a kinetically inert Pt-N bond have been synthesized from the stepwise assembly of a Pt-corner, linear linker 4,4'-bipy (4,4'-bipy = 4,4'-bipyridine) and triangular ligand [tpb or tpt, tpb = tris(4-pyridyl)benzene, tpt = tris(4-pyridyl)triazine]. The use of an unsymmetrical [Pt(HL)]-corner (H2L = 2,6-diphenylpyridine) leads to novel isostructural products. Phenyl rotation at the metal-corners endows these complexes with good aggregation-induced emission (AIE) function, with varied activities across the isostructural complexes. The coordination sequence of electron-deficient ligand tpt also imparts significant influence on the complex emission. These organoplatinum triangular metallaprisms thus provide a good model to study the influence of building blocks and coordination sequence on the luminescence of supramolecules.

A Robust Hybrid Zn-Battery with Ultralong Cycle Life.

Advanced batteries with long cycle life and capable of harnessing more energies from multiple electrochemical reactions are both fundamentally interesting and practically attractive. Herein, we report a robust hybrid zinc-battery that makes use of transition-metal-based redox reaction (M-O-OH → M-O, M = Ni and Co) and oxygen reduction reaction (ORR) to deliver more electrochemical energies of comparably higher voltage with much longer cycle life. The hybrid battery was constructed using an integrated electrode of NiCo2O4 nanowire arrays grown on carbon-coated nickel foam, coupled with a zinc plate anode in alkaline electrolyte. Benefitted from the M-O/M-O-OH redox reactions and rich ORR active sites in NiCo2O4, the battery has concurrently exhibited high working voltage (by M-O-OH → M-O) and high energy density (by ORR). The good oxygen evolution reaction (OER) activity of the electrode and the reversible M-O ↔ M-O-OH reactions also enabled smooth recharging of the batteries, leading to excellent cycling stabilities. Impressively, the hybrid batteries maintained highly stable charge-discharge voltage profile under various testing conditions, for example, almost no change was observed over 5000 cycles at a current density of 5 mA cm-2 after some initial stabilization. With merits of higher working voltage, high energy density, and ultralong cycle life, such hybrid batteries promise high potential for practical applications.

Hydrogen-Bonding Interactions in Luminescent Quinoline-Triazoles with Dominant 1D Crystals.

Quinoline-triazoles 2-((4-(diethoxymethyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (1), 2-((4-(m-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (2) and 2-((4-(p-tolyl)-1H-1,2,3-triazol-1-yl)methyl)quinoline (3) have been prepared with CuAAC click reactions and used as a model series to probe the relationship between lattice H-bonding interaction and crystal direction of growth. Crystals of 1-3 are 1D tape and prism shapes that correlate with their intermolecular and solvent 1D lattice H-bonding interactions. All compounds were thermally stable up to about 200 C and blue-green emissive in solution.

The effect of crystallinity on photocatalytic performance of Co3O4 water-splitting cocatalysts.

Cocatalysts, when loaded onto a water splitting photocatalyst, accelerate the gas evolution reaction and improve the efficiency of the photocatalyst. In this paper, we report that the efficiency of the photocatalyst is enhanced using an amorphous cobalt oxide cocatalyst. The WO3 film, when loaded with amorphous or nanocrystalline Co3O4, shows an improvement of up to 40% in photocurrent generation and 34% in hydrogen gas evolution. The effect of cocatalyst crystallinity on performance was systematically studied, and we found that the photocurrent deteriorates with the conversion of the cocatalyst to a highly crystalline phase at an annealing temperature of 500 °C. The mechanism of this effect was studied in detail using electrochemical impedance spectroscopy, and the enhancement effect produced by the amorphous cocatalyst is attributed to the large density of unsaturated catalytically active sites in the amorphous material.

Recent advances in C-S bond formation via C-H bond functionalization and decarboxylation.

The development of mild and general methods for C-S bond formation has received significant attention because the C-S bond is indispensable in many important biological and pharmaceutical compounds. Early examples for the synthesis of C-S bonds are generally limited to the condensation reaction between a metal thiolate and an organic halide. Recent chemical approaches for C-S bond formation, based upon direct C-H bond functionalization and decarboxylative reactions, not only provide new insights into the mechanistic understanding of C-S coupling reactions but also allow the synthesis of sulfur-containing compounds from more effective synthetic routes with high atom economy. This review intends to explore recent advances in C-S bond formation via C-H functionalization and decarboxylation, and the growing opportunities they present to the construction of complex chemical scaffolds for applications encompassing natural product synthesis, synthetic methodology development, and functional materials as well as nanotechnology.

Nickel-catalyzed three-component domino reactions of aryl Grignard reagents, alkynes, and aryl halides producing tetrasubstituted alkenes.

Three-component reaction of aryl Grignard reagents, alkynes, and aryl halides in the presence of 1 mol % of NiCl2 proceeded sequentially through carbomagnesiation of the alkyne followed by cross-coupling of the resulting alkenyl Grignard reagent with aryl halide to give tetrasubstituted alkenes in high yields.

Spacer-Directed Selective Assembly of Copper Square or Hexagon and Ring-Stacks or Coordination Nanotubes.

The use of simple self-assembly methods to direct or engineer porosity or channels of desirable functionality is a major challenge in the field of metal-organic frameworks. We herein report a series of frameworks by modifying square ring structure of [{Cu2(5-dmpy)2(L1)2(H2O)(MeOH)}2{ClO4}4]·4MeOH (1·4MeOH, 5-dmpy = 5,5'-dimethyl-2,2'-bipyridine, HL1 = 4-pyridinecarboxylic acid). Use of pyridyl carboxylates as directional spacers in bipyridyl chelated Cu(II) system led to the growth of square unit into other configurations, namely, square ring, square chain, and square tunnel. Another remarkable characteristic is that the novel use of two isomers of pyridinyl-acrylic acid directs selectively to two different extreme tubular forms-aligned stacking of discrete hexagonal rings and crack-free one-dimensional continuum polymers. This provides a unique example of two extreme forms of copper nanotubes from two isomeric spacers. All of the reactions are performed in a one-pot self-assembly process at room temperature, while the topological selectivity is exclusively determined by the skeletal characteristics of the spacers.

Transmetalation of a dodecahedral Na9 aggregate-based polymer: a facile route to water stable Cu(II) coordination networks.

A variety of network structures have been prepared by transmetalation of a polymer {Na3[Na9(Cbdcp)6(H2O)18]}n (1) (Cbdcp = N-(4-carboxybenzyl)-(3,5-dicarboxyl)pyridinium) containing dodecahedral Na9 aggregate secondary building units with Cu(II) by modulating the temperature, solvent, and pH. These complexes include a large, zwitterionic hexa-cuprometallocycle [Cu6(Cbdcp)6(H2O)18] (2) formed in H2O at room temperature, two three-dimensional polymers [Cu3(Cbdcp)2(OH)2(H2O)2]n (3) and {[Cu3(Cbdcp)2(OH)2]·2H2O}n (4) isolated from H2O and DMF/H2O at 135 °C, and a mononuclear complex [Cu(HCbdcp)2(H2O)3]·H2O (5) from H2O at 100 °C and pH = 6. All the complexes are robust and water stable. The crystal framework of macrocycle 2 is stable up to 100 °C under vacuum and selectively adsorbs CO2.

Stitching 2D polymeric layers into flexible interpenetrated metal-organic frameworks within single crystals.

A 2D coordination polymer prepared with bulky diethylformamide solvates exhibits channels which allow dipyridyl bridging ligands to diffuse into the crystal lattice. The absorbed dipyridyls thread through the pores of one layer and substitute the surface diethylformamide molecules on the neighboring layers to stitch alternate layers to form flexible interpenetrated metal-orgaic frameworks. The threading process also results in exchange of the bulky diethylformamide solvates for aqua to minimize congestion and, more strikingly, forces the slippage of two-dimensional layers, while still maintaining crystallinity.

Cp*Rh-based heterometallic metallarectangles: size-dependent Borromean link structures and catalytic acyl transfer.

A series of Cp*Rh-based functional metallarectangles have been synthesized from metallaligands. Enlargement of one linker leads to the isolation of two novel Borromean link architectures. All these complexes are intact in solution, as evident from ESI-MS spectroscopic analysis. Arising from the combination of open Cu centers and favorable cavity space, {(Cp*Rh)4(bpe)2[Cu(opba)·2MeOH]2}4(OTf)·6MeOH shows extraordinary catalytic abilities with high efficiency and wide substrate selectivity in the acyl-transfer reaction.

Tuning omniphobicity via morphological control of metal-organic framework functionalized surfaces.

Fabrication of microstructures for imparting omniphobicity to a surface generally requires the use of lithographic techniques and specialized equipment. We report instead a simple strategy for the synthesis of microstructured surfaces via metal­organic framework (MOF) self-assembly. Our method allows us to localize epitaxial growth of MOF at the tips of needle crystals to create mushroom-shaped structures, thus conferring re-entrant textures to the MOF-functionalized surfaces. These structures synthesized via wet chemistry were found to have omniphobic properties due to the resulting re-entrant texture.

General one-step self-assembly of isostructural intermetallic Co(II)(3)Ln(III) cubane aggregates.

A new family of Co/rare-earth intermetallic cubane aggregates [Co3Ln(hmp)4(OAc)5H2O] (Ln = Dy, Ho, Er, Tm, Yb, Y) have been synthesized by self-assembly. Single-crystal X-ray diffraction analysis revealed that they are remarkably isostructural in showing a common [Co3Ln] core. Magnetic studies showed that the Dy, Er, Tm, Yb, and Y complexes are ferromagnetic. The Dy complex exhibits the largest magnetocaloric effect (-ΔSm = 12.58 J kg(-1) K(-1)), which can be attributed to the large magnetic density of Dy(III).

A New Potent Antimicrobial Metalloporphyrin.

A series of bis-acryl functionalized porphyrins and their corresponding metalloporphyrins (M=Co, Mn) were synthesized and investigated for their antimicrobial properties through MIC screening and bacteria time-kill kinetic studies. The Mn(III) 4-(bis)methylphenyl-substituted-porphyrins showed superior batericidal activities even in the dark with low hemotoxicity and good cytotoxicity profile.

Magnetically recoverable magnetite/gold catalyst stabilized by poly(N-vinyl-2-pyrrolidone) for aerobic oxidation of alcohols.

Fe(3)O(4):PVP/Au nanocomposite synthesized via a two-step procedure was tested as a quasi-homogenous alcohol oxidation catalyst. It was found that the nanocomposite was able to carry out aerobic oxidation of alcohols in water at room temperature. Studies show rapid magnetic recoverability and reusability characteristics.

Facile synthesis of nitrogen tetradentate ligands and their applications in Cu(I)-catalyzed N-arylation and azide-alkyne cycloaddition.

Five new tetradentate ligands [NNNN] with benzimidazolyl-imine or amine nitrogen donors have been synthesized in good yields under mild conditions from easily available substrates. trans-N,N'-bis(1-Ethyl-2-benzimidazolylmethylene)cyclohexane-1,2-diimine is the best accelerating ligand in this series that supports the Cu(I)-catalyzed Ullmann N-arylation and the direct three-component azide-alkyne cycloaddition reaction to give the corresponding substituted imidazole, pyrazole, and triazole in high yields. Single-crystal X-ray diffraction analysis of its complex with CuI reveals a novel one-dimensional coordination polymer of the metal chain bridged alternately by the [NNNN] ligand and diiodides.

One-pot oxidation and protonation of a bridging sulfide and rare crystallographic evidence of a coordinated [SO] complex in [Pt2(micro-S2O2H)(PPh3)4]+.

One-pot oxidation and protonation of the sulfide bridging complex [Pt(2)(micro-S)(2)(PPh(3))(4)] can be promoted by lanthanide or scandium compounds, leading to the isolation of [Pt(2)(micro-S(2)O(2)H)(PPh(3))(4)](+); crystallographic elucidation confirmed sulfide mono-oxygenation without S-S bonding to give formally [SO](2-) in the form of an [SOHOS](3-) overhead bridge.

Structures of copper complexes of the hybrid [SNS] ligand of bis(2-(benzylthio)ethyl)amine and facile catalytic formation of 1-benzyl-4-phenyl-1H-1,2,3-triazole through click reaction.

A hybrid ligand, bis(2-(benzylthio)ethyl)amine (SNS), with an amine and two thioether donors reacts with Cu(II) to give mononuclear [CuCl(2)(SNS)] (1), [CuBr(2)(SNS)] (2), [Cu(OTf)(2)(SNS)(OH(2))] (3), and an one-dimensional Cu(I) coordination polymer [Cu(2)I(2)(SNS)](n) (4). All complexes have been characterized by single-crystal X-ray diffraction analysis, and 1-3 were studied by EPR analysis at room temperature. Complexes 1 and 2 are penta-coordinated with a distorted square pyramidal metal supported by a tridentate SNS ligand on the basal plane. Complex 3 shows a tetragonally distorted octahedral sphere with two trans and weakly bonding monodentate triflates. A 12-membered ring in the solid lattice is formed by intermolecular H-bonding among the coordinated triflate and aqua ligands from four neighboring molecules. Complex 4, the only Cu(I) in this series, shows a coordination polymer chain [Cu(4)I(4)](n) comprising tetrahedral Cu(I) centers stitched by the SNS ligand in a unique bridge-chelate mode in the form of a helix. All four complexes are catalytically active at room temperature in a copper-catalyzed azide-alkyne cycloaddition (CuAAA) three-component click reaction of benzyl chloride, sodium azide, and phenylacetylene in an aqueous MeCN mixture to give good isolated yields of 1-benzyl-4-phenyl-1H-1,2,3-triazole, without the use of a base or reducing agent.

Metal-salen molecular cages as efficient and recyclable heterogeneous catalysts for cycloaddition of CO2 with epoxides under ambient conditions.

A salen based molecular cage, salen@cage, was synthesized and complexed with Co and Al to yield metal-salen molecular cages, Co(ii)@cage, Co(iii)@cage and Al(iii)@cage. These cages were demonstrated to be efficient heterogeneous catalysts for the cycloaddition of CO2 with styrene oxide, achieving full conversion at 25 °C and 1 atm CO2. Good to excellent yields of various cyclic carbonates were also achieved under mild conditions. Al(iii)@cage can be reused up to five times without any significant loss of its high catalytic activity. The capability to access a variety of heterogeneous organometallic catalysts with salen@cage offers new prospects for practical CO2 utilization and chemical manufacturing.

Isolation of an [SNS]Pd(II) pincer with a water ladder and its Suzuki coupling activity in water.

A water-compatible Pd(ii) pincer with a hybrid [SNS]-donor set, [L(1)PdCl]Cl.2H(2)O [L(1) = bis-(2-(i-butylsulfanyl)-ethyl)-amine] has been isolated and crystallographically characterized; its solid lattice at 223 K contains a ladder-like water polymer of tetramers and extensive H-bonding exists among the cation, anion and water cluster, and this water-soluble complex is active in Suzuki-Miyaura coupling of phenylboronic acid and selected aryl bromides in water at 75 degrees C.

Spacer-directed coordination polymers-of-oligomers (POLO) of silver.

A novel series of Ag(I) polymers-of-oligomers with pyridylcarboxylate spacers supported by a diphosphine [1,1'-bis(diphenylphosphino)methane (dppm) or 1,1'-bis(diphenylphosphino)ferrocene (dppf)] has been constructed and crystallographically established. The repeating oligomeric Ag5 block is invariably made up of five Ag(I) centers comprising Ag2 and Ag units with different metal geometries. Other related Ag5 and Ag4 assemblies have also been isolated. The preparation of the [Ag2(isonic)(dppm)2]n(n+) polymer (isonic = 4-pyridyl formate, NC5H4CO2(-)) using a ligand transfer pathway from NiCl2(dppm) to AgOTf (OTf = CF3SO3(-)) has been identified. The structural outcomes suggested that pyridylcarboxylates of different stereogeometrical and conformational properties can stabilize different oligomeric and topological forms through adaptation to the contrasting demands of the diphosphine and metal.