Discrete Platinum(II/IV)-Arsenito Clusters with Pt-As and Pt-O Bonding: [Pt(AsO)], [Pt(HAsO)(HAsO)], and [PtAsWO].

The first two discrete, fully inorganic platinum(II/IV)-arsenito clusters, [-Pt(AsO)] () and [Pt(HAsO)(HAsO)] (), as well as the platinum(II)-arsenito heteropolytungstate [PtAsWO] (), have been synthesized in aqueous media using simple one-pot reaction conditions. In , a Pt ion is coordinated to two cyclic, tridentate AsO units via oxo-donation (Pt-O ∼ 2.02 Å).

Pt-Containing Hexaplatinate(II) [PtPtO(AsO(CH))] and Hexapalladate(II) [PtPdO(AsO(CH))].

The first Pt-containing discrete polyoxoplatinate(II) [PtPtO(AsO(CH))] () and polyoxopalladate(II) [PtPdO(AsO(CH))] () have been prepared and characterized in the solid state, in solution, and in the gas phase. The molecular structures of the noble metal-oxo clusters and comprise a central, octahedral PtO hetero group surrounded by six square-planar MO (M = Pt, Pd) units, which are capped by six dimethylarsinate ligands. The polyanions were prepared under simple one-pot aqueous solution conditions by reacting HPt(OH) with either KPtCl or Pd(NO) in sodium dimethylarsinate buffer (pH 7) at 80 °C.

Layer-by-Layer Construction of a Nanoarchitecture by Polyoxometalates and Polymers: Enhanced Electrochemical Hydrogen Evolution Reaction.

In this contribution, a nanoarchitectural approach was employed to produce a nanolayer of polyoxometalate (POM) on the surface of a glassy carbon electrode (GCE) to achieve a higher surface area with higher electrocatalytic activity toward the electrochemical hydrogen evolution reaction (HER). To accomplish this, the well-known layer-by-layer (LbL) technique was employed, which involved the alternate adsorption of the POM, Na[N(CH)] [(MoO)(OPC(O)(CHNHCHCHS)PO)], abbreviated as [(TBA)Mo(AleThio)], and polyethyleneimine (PEI) polymer. This nanolayered electrode exhibited catalytic properties toward the HER in 0.

Mixed-valent palladium(IV/II)-oxoanion, [PdOPdII6((CH)AsO)].

We report on the first example of a Pd-containing polyoxopalladate(II). The discrete mixed-valent polyoxopalladate(IV/II), [PdPdII6O((CH)AsO)], comprising a central Pd ion that is surrounded by a six-membered Pd-oxo ring capped by six dimethylarsinate groups, was synthesized and structurally characterized in the solid state, in solution and in the gas phase by multiple analytical techniques.

Binder-Free Fabrication of Prussian Blue Analogues Based Electrocatalyst for Enhanced Electrocatalytic Water Oxidation.

Developing a cost-effective, efficient, and stable oxygen evolution reaction (OER) catalyst is of great importance for sustainable energy conversion and storage. In this study, we report a facile one-step fabrication of cationic surfactant-assisted Prussian blue analogues (PBAs) M[Fe(CN)CHCHNH]∙yCHNBr abbreviated as SF[Fe-Tol-M] (where SF = N-tridecyl-3-methylpyridinium bromide and M = Mn, Co and Ni) as efficient heterogeneous OER electrocatalysts. The electrocatalysts have been characterized by Fourier transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) coupled with energy dispersive X-ray (EDX) analysis, and X-ray photoelectron spectroscopy (XPS).

Discovery of Polythioplatinate(II) [PtS(SO)] and Study of Its Solution and Catalytic Properties.

We have discovered the first polythioplatinate(II), [PtS(SO)] (), which was synthesized in aqueous basic medium (pH 11) by hydrothermal heating at 150 °C. Polyanion comprises a discrete, triangular assembly of three Pt ions linked by two μ-sulfido ligands, and their square-planar coordination geometry is completed by two terminal S-bound sulfito ligands. Polyanion was isolated as a hydrated sodium salt, Na[Pt(μ-S)(SO)]·22HO (), which was characterized in the solid state by single-crystal X-ray diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, X-ray photoelectron spectra, and elemental analysis, in solution by Pt NMR and atomic absorption spectroscopy, and in the gas phase by electrospray ionization mass spectrometry.

Organically Functionalized Mixed-Valent Polyoxo-30-molybdate Wheel and Neutral Tetramolybdenum(V) Oxo Cluster.

The first organofunctionalized mixed-valent polyoxo-30-molybdate wheel, [MoMoO{AsO(CH)}] (), was synthesized in aqueous, mildly acidic conditions, and upon further acidification, the neutral tetramolybdenum(V) oxo cluster [MoO{AsO(CH)}] () was obtained. Single-crystal X-ray diffraction (XRD) revealed that comprises 18 Mo and 12 Mo ions arranged in a cyclic fashion with alternating {Mo} and {Mo} groups, which are capped by 18 dimethylarsinate ligands, resulting in a novel polyoxo-30-molybdate wheel with a central cavity of ∼1.5 nm.

Discrete Arsonate-Grafted Inverted-Keggin 12-Molybdate Ion [MoO(OH)(4-NCH-CHAsO)] and Formation of a Copper(II)-Mediated Metal-Organic Framework.

The discrete inverted-Keggin ion [MoO(OH)(4-NCH-CHAsO)] () has been prepared in an aqueous acidic (pH 0.8) medium by the reaction of MoO with the (4-triazolylphenyl)arsonic acid 4-NCH-CHAsOH under hydrothermal conditions and was isolated as a sodium salt in 21% yield. The exact same reaction in the presence of Cu ions resulted in the neutral metal-organic framework (MOF) Cu[MoO(4-NCH-CHAsO)] () in 68% yield.

Discrete, Cationic Palladium(II)-Oxo Clusters via f-Metal Ion Incorporation and their Macrocyclic Host-Guest Interactions with Sulfonatocalixarenes.

We report on the discovery of the first two examples of cationic palladium(II)-oxo clusters (POCs) containing f-metal ions, [Pd O M {(CH ) AsO } (H O) ] (M=Ce , Th ), and their physicochemical characterization in the solid state, in solution and in the gas phase. The molecular structure of the two novel POCs comprises an octahedral {Pd O } core that is capped by eight M ions, resulting in a cationic, cubic assembly {Pd O M } , which is coordinated by a total of 16 terminal dimethylarsinate and eight water ligands, resulting in the mixed Pd -Ce /Th oxo-clusters [Pd O M {(CH ) AsO } (H O) ] (M=Ce, Pd Ce ; Th, Pd Th ). We have also studied the formation of host-guest inclusion complexes of Pd Ce and Pd Th with anionic 4-sulfocalix[n]arenes (n=4, 6, 8), resulting in the first examples of discrete, enthalpically-driven supramolecular assemblies between large metal-oxo clusters and calixarene-based macrocycles.

Electrochemically Deposited Amorphous Cobalt-Nickel-Doped Copper Oxide as an Efficient Electrocatalyst toward Water Oxidation Reaction.

Production of hydrogen through water splitting is one of the green and the most practical solutions to cope with the energy crisis and greenhouse effect. However, oxygen evolution reaction (OER) being a sluggish step, the use of precious metal-based catalysts is the main impediment toward the viability of water splitting. In this work, amorphous copper oxide and doped binary- and ternary-metal oxides (containing Co, Ni, and Cu) have been prepared on the surface of fluorine-doped tin oxide by a facile electrodeposition route followed by thermal treatment.

Improving Lithium-Ion Half-/Full-Cell Performance of WO -Protected SnO Core-Shell Nanoarchitectures.

Anodes derived from SnO offer a greater specific capacity comparative to graphitic carbon in lithium-ion batteries (LIBs); hence, it is imperative to find a simple but effective approach for the fabrication of SnO . The intelligent surfacing of transition metal oxides is one of the favorite strategies to dramatically boost cycling efficiency, and currently most work is primarily aimed at coating and/or compositing with carbon-based materials. Such coating materials, however, face major challenges, including tedious processing and low capacity.

Insights into ultrafast charge-pair dynamics in P3HT:PCBM devices under the influence of static electric fields.

Polymer-fullerene blends based on poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C-butyric-acid methyl ester (PCBM) have been extensively studied as promising bulk heterojunction materials for organic semiconductor devices with improved performance. In these donor-acceptor systems where the bulk morphology plays a crucial role, the generation and subsequent decay mechanisms of photoexcitation species are still not completely understood. In this work, we use femtosecond transient absorption spectroscopy to investigate P3HT:PCBM diodes under the influence of applied static electric fields in comparison to P3HT:PCBM thin films.

Palladium(II)-Containing Tungstoarsenate(V), [Pd(AsWO)], and Its Catalytic Properties.

We have synthesized and structurally characterized the 4-palladium(II)-containing 30-tungsto-4-arsenate(V), [Pd(AsWO)] (), which represents the first palladium(II)-containing tungstoarsenate(V). The title polyanion was prepared by a simple one-pot procedure in aqueous medium and characterized by single-crystal X-ray diffraction (XRD), thermogravimetric analysis (TGA), cyclic voltammetry, elemental analysis, and W nuclear magnetic resonance (NMR), infrared (IR), and ultraviolet-visible (UV-vis) spectroscopies. Polyanion consists of four Pd ions that are coordinated in a square-planar geometry to two trilacunary [AsWO] Wells-Dawson fragments resulting in a sandwich-type assembly.

Tetra-Mn-Containing 30-Tungsto-4-phosphate, [Mn(HO)(PWO)]: Synthesis, Structure, XPS, Magnetism, and Electrochemical Study.

Reaction of the mixed-valent Mn-acetato complex [MnMnO(CHCOO)(HO)] with the trilacunary Wells-Dawson-type heteropolytungstate [PWO] in acidic acetate solution (pH 1.1) resulted in the tetra-Mn-containing polyanion [Mn(HO)(PWO)] (). Single-crystal XRD on Na[Mn(HO)(PWO)]·84HO () revealed that four Mn ions form a rhombic MnO core encapsulated by two [PWO] units.

Polyoxopalladate-Loaded Metal-Organic Framework (POP@MOF): Synthesis and Heterogeneous Catalysis.

We report on the synthesis and characterization of the first polyoxo-noble-metalate-containing metal-organic framework (MOF) material, wherein the preformed MIL-101 has been impregnated with the discrete, cuboid-shaped polyoxopalladate [PdSeO] (PdSe), leading to the composite PdSe@MIL-101. This material was characterized by FTIR, TGA, elemental analysis, powder-XRD, N sorption (BET), SEM-EDX, and XPS. Furthermore, the PdSe@MIL-101 composite was shown to be an effective, stable, and recyclable heterogeneous precatalyst for the Suzuki-Miyaura cross-coupling reaction at room temperature utilizing environmentally benign solvents, such as water and methanol.

Ultrafast polaron-pair dynamics in a poly(3-hexylthiophene-2,5-diyl) device influenced by a static electric field: insights into electric-field-related charge loss.

The generation and decay mechanisms of polaron pairs in organic semiconductor-based optoelectronic devices under operational conditions are relevant for a better understanding of photophysical processes affecting the device performance, since the possible occurrence of a polaron pair introduces an intermediate step in exciton dissociation into fully separated charge carriers. The role played by static electric fields in polaron-pair dynamics is important but poorly understood or not investigated in detail. In this work, insights into the polaron-pair dynamics in neat poly(3-hexylthiophene-2,5-diyl) (P3HT) thin films and P3HT films sandwiched between electrical contacts with an applied external static electric field are probed using femtosecond pump-probe transient absorption spectroscopy.

Peroxo-Cerium(IV)-Containing Polyoxometalates: [Ce(O)(GeWO)], a Recyclable Homogeneous Oxidation Catalyst.

The class of peroxo-cerium-containing polyoxometalates has been discovered via the synthesis of the 9-peroxo-6-cerium(IV)-containing 30-tungsto-3-germanate, [Ce(O)(GeWO)] (). Polyanion consists of a cyclic [Ce(O)] assembly that is stabilized by three dilacunary [GeWO] Keggin fragments. The title polyanion is solution-stable, on the basis of W nuclear magnetic resonance, and was shown to act as a recyclable homogeneous catalyst for the selective, microwave-activated sulfoxidation of the model substrate methionine to the sulfoxide in the absence and to the sulfone in the presence of hydrogen peroxide.

Discovery of Polyoxo-Noble-Metalate-Based Metal-Organic Frameworks.

Here we report on the synthesis, structure, and characterization of the first example of a polyoxopalladate (POP)-based metal-organic framework (MOF). This novel class of materials comprises discrete polyoxo-13-palladate(II) nanocubes [PdO(AsO)H] decorated by four Ba ions on each of two opposite faces. These secondary building units (SBUs) are linked to each other via rigid linear organic groups, resulting in a stable 3D POP-MOF framework, which exhibits interesting sorption as well as catalytic properties.

Synthesis and Characterization of Oxazaborinin Phosphonate for Blue OLED Emitter Applications.

A blue-light emitting material based on a boron complex containing heteroaromatic phosphonate ligand is synthesized and characterized. The Phospho-Fries rearrangement is used in the synthesis route of the ligand as a convenient method of introducing phosphonate groups into phenols. Structural, thermal and photophysical properties of the resulting oxazaborinin phosphonate compound have been characterized.

Toxicity and phototoxicity in human ARPE-19 retinal pigment epithelium cells of dyes commonly used in retinal surgery.

Purpose: To compare, for the first time, systematically the toxicity and phototoxicity of dyes and dye combinations used in vitreoretinal surgery. The dyes were trypan blue, brilliant blue G, trypan blue + brilliant blue G, indocyanine green, bromophenol blue, bromophenol blue + brilliant blue G, and acid violet 17, in clinically used concentrations.

Methods: Human ARPE retinal pigment epithelium cells were exposed to the dyes for 30 min.

Growth of large sized two-dimensional MoS flakes in aqueous solution.

A large lateral size and low dimensions are prerequisites for next generation electronics. Since the first single layer MoS transistor reported by Kis's group in 2011, layered transition metal dichalcogenides (TMDs) have been demonstrated to be the ideal candidate for next generation electronics. However, the development of large scale and low cost growth techniques is a crucial step towards TMDs' inclusion in modern electronics and photoelectronics.

Zinc oxide nanowire arrays for silicon core/shell solar cells.

The optics of core / shell nanowire solar cells was investigated. The optical wave propagation was studied by finite difference time domain simulations using realistic interface morphologies. The interface morphologies were determined by a 3D surface coverage algorithm, which provides a realistic film formation of amorphous silicon films on zinc oxide nanowire arrays.

On the origin of contact resistances of organic thin film transistors.

A model is presented that describes the gate-voltage-dependent contact resistance and channel-length-dependent charge carrier mobility of small-molecule-based organic thin-film transistors in top and bottom drain/source contact configuration.

Transient grating studies of femtosecond processes in ultra-thin layers of PTCDA.

Elementary processes like energy transfer, charge transport, and exciton diffusion in thin films occur on time scales of femtoseconds. Time-resolved photo-electron spectroscopy, a technique limited to ultra-high vacuum environment and the proper choice of a substrate, has been used to study ultrafast processes in sub-nanometer thin films so far. Herein we show that a transient (population) grating created by the interference of laser pulses can be used to study ultrafast processes in such films under ambient conditions.