Proton Self-Doped Polyaniline with High Electrochemical Activity for Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self-doping from manganese metal-organic frameworks (Mn-MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self-doped polyaniline cathode has a superior specific capacity (273 mAh g-1 at 0.5 A g-1 ), a high rate property (154 mAh g-1 at 20 A g-1 ), and excellent cyclability retention (87% over 4000 cycles at 15 A g-1 ). This research provides fresh insight into the development of innovative polymers as cathode materials for high-performance AZIBs.

Hierarchical spheroidal MOF-derived MnO@C as cathode components for high-performance aqueous zinc ion batteries.

Aqueous zinc-ion batteries (AZIBs) have shown great potential as energy storage devices owing to their high energy density, low cost, and low toxicity. Typically, high performance AZIBs incorporate manganese-based cathode materials. Despite their advantages, these cathodes are limited by significant capacity fading and poor rate performance due to the dissolution and disproportionation of manganese. Herein, hierarchical spheroidal MnO@C structures were synthesized from Mn-based metal-organic frameworks, which benefit from a protective carbon layer to prevent manganese dissolution. The spheroidal MnO@C structures were incorporated onto a heterogeneous interface to act as a cathode material for AZIBs, which exhibited excellent cycling stability (160 mAh g-1 after 1000 cycles at 3.0 A g-1), good rate capability (165.9 mAh g-1 at 3.0 A g-1), and appreciable specific capacity (412.4 mAh g-1 at 0.1 A g-1) for AZIBs. Moreover, the Zn2+ storage mechanism in MnO@C was comprehensively investigated using ex-situ XRD and XPS studies. These results demonstrate that hierarchical spheroidal MnO@C is a potential cathode material for high-performing AZIBs.

Using a two-step method of surface mechanical attrition treatment and calcium ion implantation to promote the osteogenic activity of mesenchymal stem cells as well as biomineralization on a ß-titanium surface.

Surface treatment is known as a very efficient measure by which to modulate the surface properties of biomaterials in terms of grain structure, topography, roughness and chemistry to determine the osseointegration of implants. In this work, a two-step method of surface modification was employed to impart high osteogenic activity and biomineralization capacity on a Ti-25Nb-3Mo-2Sn-3Zr alloy (a type of ß-titanium named TLM). The preliminary surface mechanical attrition treatment (SMAT) refined the average grain size from 170 ± 19 µm to 74 ± 8 nm in the TLM surface layer and promoted the surface to be much rougher and more hydrophilic. The subsequent Ca-ion implantation did not change the surface roughness and topography obviously, but enhanced the surface wettability of the SMAT-treated TLM alloy. The in vitro evaluations of the adhesion, proliferation, osteogenic genes (RUNX2, ALP, BMP-2, OPN, OCN and COL-I) and protein (ALP, OPN, OCN and COL-I) expressions, as well as extracellular matrix (ECM) mineralization of mesenchymal stem cells (MSCs) revealed that the initial SMAT-treated sample significantly enhanced the adhesion and osteogenic functions of MSCs compared to an untreated TLM sample, and the subsequent introduction of Ca ions onto the SMAT-derived nanograined sample further promotes the MSC adhesion, proliferation, osteo-differentiation and ECM mineralization due to the adsorption of more proteins such as laminin (Ln), fibronectin (Fn) and vitronectin (Vn) on the surface, as well as the increase in extracellular Ca concentrations. In addition, the biomineralization capacity of the samples was also evaluated by soaking them in simulated bodily fluid (SBF) at 37 °C for 28 days, and the results showed that the Ca-ion implanted sample significantly boosted the deposition of Ca and P containing minerals on its surface, which was associated with the generation of more Ti-OH groups on the surface after ion implantation. The combination of the SMAT technique and Ca-ion implantation thus endowed the TLM alloy with outstanding osteogenic and biomineralization properties, providing a potential means for its future use in the orthopedic field.

Regulating the Interlayer Spacing of Vanadium Oxide by In Situ Polyaniline Intercalation Enables an Improved Aqueous Zinc-Ion Storage Performance.

Vanadium pentoxide (V2O5) possesses great potential for application as cathode materials for aqueous zinc-ion batteries due to abundant valences of vanadium. Unfortunately, the inferior electronic conductivity and confined interlayer spacing of pristine V2O5 are not able to support fast Zn2+ diffusion kinetics, leading to significant capacity degradation, the dissolution of active species, and unsatisfactory cycling life. Herein, Zn2+ (de)intercalation kinetics is improved by the design of in situ polyaniline (PANI)-intercalated V2O5. The intercalated PANI can not only improve the conductivity and structural stability of V2O5 but also efficiently expand its interlayer spacing (1.41 nm), offering more channels for facile Zn2+ diffusion. Benefiting from these virtues, a high specific capacity of 356 mA h g-1 at 0.1 A g-1 is achieved for the PANI-intercalated V2O5 (PVO) cathode as well as a superior cycling performance (96.3% capacity retention after 1000 cycles at 5 A g-1) in an aqueous electrolyte. Furthermore, the Zn2+ storage in PVO is mainly dominated by the capacitive contribution. This work suggests that intercalating PANI in V2O5 may aid in the future development of advanced cathodes for other multivalent metal ion batteries.

Coordinately Unsaturated Manganese-Based Metal-Organic Frameworks as a High-Performance Cathode for Aqueous Zinc-Ion Batteries.

The slow Zn2+ intercalation/deintercalation kinetics in cathodes severely limits the electrochemical performance of aqueous zinc-ion batteries (ZIBs). Herein, we demonstrate a new kind of coordinately unsaturated manganese-based metal-organic framework (MOF) as an advanced cathode for ZIBs. Coordination unsaturation of Mn is performed with oxygen atoms of two adjacent -COO-. Its proper unsaturated coordination degree guarantees the high-efficiency Zn2+ transport and electron exchange, thereby ensuring high intrinsic activity and fast electrochemical reaction kinetics during repeated charging/discharging processes. Consequently, this MOF-based electrode possesses a high capacity of 138 mAh g-1 at 100 mA g-1 and a long life span (93.5% capacity retention after 1000 cycles at 3000 mA g-1) due to the above advantages. Such distinct Zn2+ ion storage performance surpasses those of most of the recently reported MOF cathodes. This concept of adjusting the coordination degree to tune the energy storage capability provides new avenues for exploring high-performance MOF cathodes in aqueous ZIBs.

Electrostatic Self-Assembly Synthesis of Three-Dimensional Mesoporous Lepidocrocite-Type Layered Sodium Titanate as a Superior Adsorbent for Selective Removal of Cationic Dyes via an Ion-Exchange Mechanism.

Three-dimensional mesoporous lepidocrocite-type layered sodium titanate (LST) was constructed at room temperature by the electrostatic interaction between Ti1-δO24δ- nanosheets and Na+ ions. The results of a systematic X-ray diffraction investigation manifested the transition from the Ti1-δO24δ- nanosheets phase to the titanate/titania phase, which determined a phase diagram as a function of the temperature and NaCl concentration. In addition, scanning electron microscopy, inductively coupled plasma-mass spectrometry, thermogravimetric and differential thermal, N2 adsorption-desorption, Raman spectroscopy, Fourier transform infrared spectroscopy, as well as ζ-potential analyses were utilized for adequate characterization of the LST physical and chemical properties. Furthermore, batch adsorption experiments demonstrated that LST had superior adsorption property and adsorption selectivity toward cationic dyes compared to those of anionic dyes. A multifarious influencing effect on the cationic dye adsorption behavior during the adsorption process was systematically investigated. Moreover, the pseudo-second-order kinetic model felicitously depicted the cationic dye adsorption behavior through an elaborate kinetic study, namely, chemisorption was the main adsorption action. Meanwhile, different adsorption isotherm models were utilized to process the experimental data, uncovering that the adsorption isotherms of cationic dyes on LST were suitable for a Langmuir isothermal model. More importantly, an ion-exchange mechanism was proposed for the cationic dye adsorption on LST, and the ion-exchange reaction occurred with a stoichiometric exchange between 1 mol of Na+ ions in the LST interlayer and 1 mol of MB molecules in the solution. In parallel, the electrochemical impedance spectroscopy and cyclic voltammogram measurements verified that the high ionic conductivity of Na+ ions in the LST interlayer resulted in a superior adsorption property. A two-step acid-base procedure was ultimately adopted to effectively regenerate LST adsorbent. This work provides not only an alternative adsorbent with superior adsorption capacity and adsorption selectivity but also some guiding significance for research on the adsorption mechanism of layered titanates.

Tailored Hydrothermal Synthesis of Specific Facet-Dominated TiO2 Nanocrystals from Lepidocrocite-Type Layered Titanate Nanosheets: Systematical Investigation and Enhanced Photocatalytic Performance.

A series of samples including leaf-like and rod-like rutile TiO2 nanoparticles with various facets exposed on the surface, parallelepiped-shaped anatase nanoparticles with [111] vertical facet exposed on the surface, irregular anatase nanoparticles, microsized six-point star-like anatase aggregates, and almond-like brookite aggregates had been hydrothermally synthesized from lepidocrocite-type layered titanate nanosheets. A systematical investigation was established to uncover the phase transition and morphological evolution from nanosheets to TiO2 polymorphs, and a phase diagram was determined by adjusting the synthesis parameters of the pH value and temperature. Two kinds of mechanisms composed of the dissolution-deposition process following Ostwald's ripening mechanism and the in situ topochemical conversion process following Ostwald's step rule had been proposed based on the time-dependent hydrothermal experiments. Briefly, the formation of the single-crystalline rutile phase appeared only at high temperatures with very low pH values, and similarly, the brookite phase strictly formed at high temperatures with a very high pH value. Nevertheless, the anatase phase could moderately appear in a wide range of temperatures and pH values. In addition, the single-crystalline rutile adopted a leaf-like morphology at low temperatures with high pH values and a rod-like morphology at high temperatures with low pH values, while the morphological evolution of anatase particles proceeded from irregular to parallelepiped-shaped and finally to six-point star-like morphology, and the crystal size was reduced from 1000 to 5 nm with decreasing pH values. Meanwhile, with the prolongation of the hydrothermal time, the layered titanate nanosheets first dissolved into the amorphous state and further converted into small anatase nanoparticles and finally to rutile or anatase nanoparticles based on the dissolution-deposition process, or the {010}-faceted layered titanate structure first converted into the [111]-vertical faceted anatase nanosheets by the topochemical transformation reaction and then split into the [111]-vertical faceted anatase nanoparticles. More importantly, the mesoporous [111]-vertical faceted anatase nanoparticles exhibited enhanced photocatalytic performance compared to that of Degussa P25, which was ascribed to its superior electronic band structure and effective charge separation. The systematical investigation in this work would be significant for consummating the preparation of the TiO2 polymorphs from layered titanate nanosheets and provided some reference values and guide schemes for the preparation of TiO2 nanoparticles with outstanding photocatalytic performance.

Identification of viral SIM-SUMO2-interaction inhibitors for treating primary effusion lymphoma.

Primary effusion lymphoma (PEL) is an aggressive B-cell malignancy without effective treatment, and caused by the infection of Kaposi's sarcoma-associated herpesvirus (KSHV), predominantly in its latent form. Previously we showed that the SUMO2-interacting motif within the viral latency-associated nuclear antigen (LANASIM) is essential for establishment and maintenance of KSHV latency. Here, we developed a luciferase based live-cell reporter system to screen inhibitors selectively targeting the interaction between LANASIM and SUMO2. Cambogin, a bioactive natural product isolated from the Garcinia genus (a traditional herbal medicine used for cancer treatment), was obtained from the reporter system screening to efficiently inhibit the association of SUMO2 with LANASIM, in turn reducing the viral episome DNA copy number for establishment and maintenance of KSHV latent infection at a low concentration (nM). Importantly, Cambogin treatments not only specifically inhibited proliferation of KSHV-latently infected cells in vitro, but also induced regression of PEL tumors in a xenograft mouse model. This study has identified Cambogin as a novel therapeutic agent for treating PEL as well as eliminating persistent infection of oncogenic herpesvirus.

Selective Hydrogen Generation from Formic Acid with Well-Defined Complexes of Ruthenium and Phosphorus-Nitrogen PN(3) -Pincer Ligand.

An unsymmetrically protonated PN(3) -pincer complex in which ruthenium is coordinated by one nitrogen and two phosphorus atoms was employed for the selective generation of hydrogen from formic acid. Mechanistic studies suggest that the imine arm participates in the formic acid activation/deprotonation step. A long life time of 150 h with a turnover number over 1 million was achieved.

Ir(III)-catalyzed C-H alkynylation of arenes under chelation assistance.

An efficient and mild Ir(III)-catalyzed, chelation assisted C-H alkynylation of arenes has been developed using hypervalent iodine alkynes as alkynylating reagents. A broad scope of N-phenyl-2-aminopyridines and 2-phenoxypyridines has been established as effective substrates for this C-H functionalization and the desired alkynylated products were isolated in moderate to high yields.

Rhodium(iii)-catalyzed annulation of arenes with alkynes assisted by an internal oxidizing N-O bond.

Rh(iii)-catalyzed C-H activation of 3-aryl-dihydroisoxazoles in the coupling with diarylacetylenes has been developed under redox-neutral conditions. This reaction occurred under mild conditions with no by-product, and the N-O bond functions as an oxidizing directing group, leading to efficient synthesis of isoquinolines functionalized with a proximal secondary alcohol.

C-H and H-H bond activation via ligand dearomatization/rearomatization of a PN³P-rhodium(I) complex.

A neutral complex PN(3)P-Rh(I)Cl (2) was prepared from a reaction of the PN(3)P pincer ligand (1) with [Rh(COD)Cl]2 (COD = 1,5-cyclooctadiene). Upon treatment with a suitable base, H-H and C(sp(2))-H activation reactions can be achieved through the deprotonation/reprotonation of one of the N-H arms and dearomatization/rearomatization of the central pyridine ring with the oxidation state of Rh remaining I.

Cubic and doubly-fused cubic samarium clusters from Sm(II)-mediated reduction of organic azides and azobenzenes.

A polynuclear samarium imido complex [(L)Sm(4)(µ(3)-NSiMe(3))(4)] (2) featuring a cubane-like cluster has been synthesized from the reaction of an organic azide and a samarium(II) complex [(L)SmI(2)Li(2)(THF)(Et(2)O)(2)] (1). In addition, this divalent samarium starting material (1) reacts with azobenzene to give the first example of a well-defined doubly-fused cubic imido-cluster [(L)Sm(6)(µ(3)-NPh)(4)(µ(4)-NPh)(2)I(2)(THF)(2)] (4) in addition to a major cubic complex [(L)Sm(4)(µ(3)-NPh)(4)] (3).

A heterometallic sandwich complex of europium(II) for luminescent studies.

A divalent europium complex [(L(Ph))(2)Eu{K(THF)(2)}(2)] (L(Ph) = Ph(2)Si(NAr)(2), Ar = 2,6-(i)Pr(2)C(6)H(3)) (THF = Tetrahydrofuran) (2), which has a sandwich structure with potassium-arene π interactions, was synthesized in high yield via a one-pot process. This complex has been fully characterized, and luminescent studies showed that the 528 nm emission peak can be attributed to the 4f-5d transition of Eu(2+).

Rh(III)-catalyzed oxidative coupling of N-aryl-2-aminopyridine with alkynes and alkenes.

[RhCp*Cl(2)](2) (1-2 mol %) can catalyze the oxidative coupling of N-aryl-2-aminopyridines with alkynes and arylates to give N-(2-pyridyl)indoles and N-(2-pyridyl)quinolones, respectively, using Cu(OAc)(2) as an oxidant. Coupling with styrenes gave mono- and/or disubstituted olefination products.

Rh-catalyzed oxidative coupling between primary and secondary benzamides and alkynes: synthesis of polycyclic amides.

A methodology for the high yield and facile synthesis of isoquinolones from benzamides and alkynes via the oxidative ortho C-H activation of benzamides has been developed. Ag(2)CO(3) proved to be an optimal oxidant when MeCN was used as a solvent, and [RhCp*Cl(2)](2) was utilized as an efficient catalyst. Both N-alkyl and N-aryl secondary benzamides can be applied as effective substrates. Furthermore, primary benzamides react with two alkyne units, leading to tricyclic products via double C-H activation and oxidative coupling. The reactivity of the structurally related 1-hydroxyisoquinoline was also demonstrated, where both N- and O-containing rhodacyclic intermediates can be generated, leading to the construction of different O- or N-containing heterocycles.

Tetracarboxylate-based Co(II), Ni(II) and Cu(II) three-dimensional coordination polymers: syntheses, structures and magnetic properties.

Methylenediisophthalic acid (H(4)MDIP), as semi-rigid 'V'-shaped carboxylate ligands, react with CoO, NiO and Cu(NO(3))(2)·3H(2)O to give three novel coordination polymers [H(3)O](2)[Co(3)(MDIP)(2)]·2DMF (1), [Ni(2)(HMDIP)(µ(2)-OH)(H(2)O)(3)(DMF)]·4H(2)O·DMF (2) and [Cu(3)(MDIP)(µ(2)-OH)(2)(H(2)O)(4)]·6.5H(2)O (3) (DMF = N,N'-dimethylformamide). All compounds have been characterized by thermogravimetric analysis, IR spectroscopy, elemental and single-crystal X-ray diffraction analyses. Complex 1 is an unusual open anionic framework that is defined as the metal-organic replica of fluorite. Both 2 and 3 features a 3D open framework with one-dimensional elliptical channels and R- and L-helical chains, and their resulting frameworks can be rationalized as crb and pts topology respectively. An interesting feature of complex 3 is the presence of the linear Cu(3) units that is formed by carboxylate and µ(2)-hydroxyl groups linking three Cu(II) metal centers. Magnetic investigations indicate that ferromagnetic couplings are dominant in the three compounds.

Mn(II)-based MIL-53 analogues: synthesis using neutral bridging mu2-ligands and application in liquid-phase adsorption and separation of C6-C8 aromatics.

Four Mn(II)-based MIL-53 single crystals were prepared using four neutral pyridine N-oxides as bridging mu(2)-ligands. In the case of 4,4'-bipridine-N,N'-dioxide (BPNO), the infinite manganese oxide chains were further interconnected by BPNO besides BDC, which allows 1D channels to be accessible for guest molecules. The liquid-phase adsorption and separation of C6-C8 aromatics using the evacuated compound as an absorbent were investigated via crystal-to-crystal transformations. Both structural evolution of the compounds and selectivity of C6-C7 aromatics of one evacuated compound could be attributed to noncovalent interactions, especially pi-pi interaction.

Lanthanide-alkali metal sandwich complexes: synthesis, structure, and solvent-mediated redox transformations, and one-dimensional frameworks assembled through cation-arene pi interactions.

Reaction of the potassium salt of amido ligand [Ph(2)Si(NAr)(2)](2-) (L, Ar = 2,6-iPr(2)C(6)H(3)) and LnI(2)(thf)(2) (Ln = Sm, Yb) gives sandwich complexes [(L)(2)Ln{K(Et(2)O)}(2)] (Ln = Sm (2), Yb (3)) with potassium-arene pi interactions. Reaction of 2 with azobenzene gave the dimeric samarium cluster [(L)(2)Sm(2)(mu-eta(2):eta(2)-N(2)Ph(2))(2){K(thf)(2)}(2)] (4) and the tetrameric [(L)Sm(4) (mu-eta(2):eta(2)-N(2)Ph(2))(3) (mu(3)-NPh)(2)(thf)(3)] (5). On the other hand, the reaction of 2 with alpha-diimines ligands ArN=CRCR=NAr (DAD, R = H, Me) gives two Sm(III) complexes: polymeric [(L)Sm{(ArN)RC=CR(NAr)}K](n) (R = H (6), Me (7)) assembled through cation-pi interactions and byproduct [{(L)(2)Sm}{K(thf)(6)}] (8). Complexes 2-8 have been fully characterized by elemental analyses and X-ray crystallography. In particular, crystallographic analyses of 6 and 7 revealed that in both complexes samarium(III) is stabilized by dianionic DAD units.