Prussian blue analogue derived from leather waste as a bifunctional catalyst in zinc-air batteries.

A Prussian blue analogue was synthesized using biomass leather waste as a precursor by doping with Co2+ ions. This material, demonstrates good performance in both the oxygen reduction reaction and oxygen evolution reaction, and exhibits excellent charge-discharge performance and stability in zinc-air batteries.

A new inexpensive ultrasound-guided central venous catheterization simulation model.

BACKGROUND: Central venous catheters (CVCs) are life-saving tools for fluid therapy during surgery. Ultrasound-guided CVC placement has been shown to be safe and highly efficient. However, it is difficult for medical workers with less experience in ultrasonography to acquire the necessary skill in a short time. Simulation-based training is a good way to enhance the skill of a beginner. Therefore, in this study, we introduced a new, inexpensive and easily implemented model for ultrasound-guided CVC placement training and assessed the feasibility of this model. METHODS: This was a quasi-experimental study. Thirty-three anaesthesiology postgraduate year 2 and 3 residents with strong CVC interest were included in a simulator-based training workshop in a department of anaesthesiology. The simulation model consisted of a piece of pork and two latex catheters filled with red and blue ink. The workshop comprised 3 parts: a 10-min introductory lecture, a 15-min orientation on performing ultrasound-guided CVC insertion based on the model, and a 30-min practice session. Participants completed relevant questionnaires before and after the training. Moreover, an examination was held to evaluate their skill with the novel model. RESULTS: All participants indicated that the novel model increased their self-perceived confidence in ultrasound-guided catheterization. They also all reported that the model was adequate for training anaesthesiology residents in ultrasound-guided catheterization. A few individuals thought the model did not mimic the progress of CVC insertion (3 of 33). After training, participants did not show a significant difference in the acquisition of central venous catheterization theory. However, their competency with ultrasound-guided CVC placement was enhanced. This was demonstrated not only based on subjective answers to the following questions, namely, "how do you perform central venous catheterization with ultrasound guidance?" (p < 0.001), "can you perform ultrasound-guided central venous catheterization?" (p < 0.001), and "how much self-confidence do you have in performing ultrasound-guided central venous catheterization?" (p < 0.001), but also in objective performance (evaluation of the core step in ultrasound-guided placement (p < 0.001)). CONCLUSION: The new simulator is a feasible, inexpensive and easily reproducible tool for training anaesthesiologists in ultrasound-guided central venous catheterization. After the simulation-based training workshop, the competency of residents in performing central venous catheterization with ultrasound guidance improved.

Pd/silicalite-1: An highly active catalyst for the oxidative removal of toluene.

Catalytic combustion is thought as an efficient and economic pathway to remove volatile organic compounds, and its critical issue is the development of high-performance catalytic materials. In this work, we used the in situ synthesis method to prepare the silicalite-1 (S-1)-supported Pd nanoparticles (NPs). It is found that the as-prepared catalysts displayed a hexagonal prism morphology and a surface area of 390-440 m2/g. The sample (0.28Pd/S-1-H) derived after reduction at 500°C in 10 vol% H2 showed the best catalytic activity for toluene combustion (T50% = 180°C and T90% = 189°C at a space velocity of 40,000 mL/(g·hr), turnover frequency (TOFPd) at 160°C = 3.46 × 10-3 sec-1, and specific reaction rate at 160°C = 63.8 µmol/(gPd·sec)), with the apparent activation energy (41 kJ/mol) obtained over the best-performing 0.28Pd/S-1-H sample being much lower than those (51-70 kJ/mol) obtained over the other samples (0.28Pd/S-1-A derived from calcination at 500°C in air, 0.26Pd/S-1-im derived from the impregnation route, and 0.27Pd/ZSM-5-H prepared after reduction at 500°C in 10 vol% H2). Furthermore, the 0.28Pd/S-1-H sample possessed good thermal stability and its partial deactivation due to CO2 or H2O introduction was reversible, but SO2 addition resulted in an irreversible deactivation. The possible pathways of toluene oxidation over 0.28Pd/S-1-H was toluene â†’ p-methylbenzoquinone â†’ maleic anhydride, benzoic acid, benzaldehyde â†’ carbon dioxide and water. We conclude that the good dispersion of Pd NPs, high adsorption oxygen species concentration, large toluene adsorption capacity, strong acidity, and more Pd0 species were responsible for the good catalytic performance of 0.28Pd/S-1-H.

Gold/alpha-lactalbumin nanoprobes for the imaging and treatment of breast cancer.

Theranostic agents should ideally be renally cleared and biodegradable. Here, we report the synthesis, characterization and theranostic applications of fluorescent ultrasmall gold quantum clusters that are stabilized by the milk metalloprotein alpha-lactalbumin. We synthesized three types of these nanoprobes that together display fluorescence across the visible and near-infrared spectra when excited at a single wavelength through optical colour coding. In live tumour-bearing mice, the near-infrared nanoprobe generates contrast for fluorescence, X-ray computed tomography and magnetic resonance imaging, and exhibits long circulation times, low accumulation in the reticuloendothelial system, sustained tumour retention, insignificant toxicity and renal clearance. An intravenously administrated near-infrared nanoprobe with a large Stokes shift facilitated the detection and image-guided resection of breast tumours in vivo using a smartphone with modified optics. Moreover, the partially unfolded structure of alpha-lactalbumin in the nanoprobe helps with the formation of an anti-cancer lipoprotein complex with oleic acid that triggers the inhibition of the MAPK and PI3K-AKT pathways, immunogenic cell death and the recruitment of infiltrating macrophages. The biodegradability and safety profile of the nanoprobes make them suitable for the systemic detection and localized treatment of cancer.

Co3O4 nanoparticles embedded in nitrogen-doped graphitic carbon fibers as a free-standing electrode for promotion of lithium ion storage with capacitive contribution.

Here, we wrap Co3O4 nanoparticles with nitrogen-doped graphitic carbon nanofibers (Co3O4@NGFs) as a self-standing electrode for lithium-ion batteries. In this structure, graphitic carbon acts as a composite framework that enhances conductivity, accommodates volume expansion and increases contact with the electrolyte. Meanwhile, the porosity of Co3O4@NGFs not only facilitates rapid electron transfer, but also exposes more active sites for lithium storage.

Crystal Structures, Photoluminescence, and Magnetism of Two Novel Transition-Metal Complex Cocrystals with Three-Dimensional H-Bonding Organic Framework or Alternating Noncovalent Anionic and Cationic Layers.

Cocrystallization may alter material physicochemical properties; thus, the strategy of forming a cocrystal is generally used to improve the material performance for practical applications. In this study, two transition-metal complex cocrystals [Zn(bpy)3]H0.5BDC·H1.5BDC·0.5bpy·3H2O (1) and [Cu2(BDC)(bpy)4]BDC·bpy·2H2O (2) have been achieved using a hydrothermal reaction, where bpy and H2BDC represent 2,2'-bipyridine and benzene-1,3-dicarboxylic acid, respectively. Cocrystals were characterized by microanalysis, infrared spectroscopy, and UV-visible spectroscopy. Cocrystal 1 contains five components and crystallizes in a monoclinic space group P21/n. The H0.5BDC1.5-, H1.5BDC0.5-, and H2O molecules construct three-dimensional H-bonding organic framework; the [Zn(bpy)3]2+ coordination cations and uncoordinated bpy molecules reside in channels, where two coordinated bpy ligands in [Zn(bpy)3]2+ and one uncoordinated bpy adopt sandwich-type alignment via π···π stacking interactions. Cocrystal 2 with four components crystallizes in a triclinic space group P-1 to form alternating layers; the binuclear [Cu2(bpy)4(BDC)]2+ cations and uncoordinated bpy molecules build the cationic layers, and the BDC2- species with disordered lattice water molecules form the anionic layers. Cocrystal 1 shows intense photoluminescence at an ambient condition with a quantum yield of 14.96% and decay time of 0.48 ns, attributed to the π* → π electron transition within phenyl/pyridyl rings, and 2 exhibits magnetic behavior of an almost isolated spin system with rather weak antiferromagnetic coupling in the [Cu2(bpy)4(BDC)]2+ cation.

Stereochemically Active and Inactive Lone Pairs in Two Room-Temperature Phosphorescence Coordination Polymers of Pb2+ with Different Tricarboxylic Acids.

Two new Pb2+-based coordination polymers (CPs), [Pb2(HBTC)2(DMF)] (1) and [Pb(HPTC)] (2), have been synthesized under solvothermal condition; herein, H3BTC and H3PTC represent 1,3,5-benzenetricarboxylic acid and 2,4,6-pyridine tricarboxylic acid, respectively. Both 1 and 2 were characterized by microanalysis, infrared spectra (IR), thermal gravimetric analyses (TGA), and powder X-ray diffraction (PXRD) techniques. Single-crystal structural analysis indicates that 1 and 2 show different coordination sphere around Pb2+ ions and distinct coordination frameworks. The I1O2 type three-dimensional (3D) nonporous metal-organic framework forms in 1, where the Pb2+ ion shows holo-directed coordination geometry, while the I0O2 type two-dimensional (2D) coordination polymeric layered structure forms in 2, where Pb2+ ion shows a hemidirected coordination sphere and the 6s2 lone electron pair in Pb2+ ion is stereochemically active. The two CPs emit intense and long-lasting greenish phosphorescence in air at room temperature, with absolute quantum yields of 1.2% for 1 and 4.7% for 2 and decay lifetimes of 0.73 ms for 1 and 1.52 ms for 2.

Nearly Pure Red Color Upconversion Luminescence of Ln-Doped Sc2O3 with Unexpected RE-MOFs Molecular Alloys as Precursor.

Unexpected Sc/Ln codoped rare earth metal-organic frameworks (RE-MOFs) molecular alloys (MAs) based on an oxalic acid ligands were obtained. Calcination of the RE-MOFs MAs gave the corresponding codoped rare earth oxides a strong and nearly pure red color upconversion luminescence. It allows the resulting lanthanide ion (Ln3+) doped upconversion materials a wide range of applications from optical communications to disease diagnosis. Moreover, the pyrolysis RE-MOFs MAs precursor has demonstrated to be an effective preparation method for a uniform Ln-doped Sc2O3 system.

A cyanine-modified upconversion nanoprobe for NIR-excited imaging of endogenous hydrogen peroxide signaling in vivo.

Endogenous hydrogen peroxide is an important parameter associated with cellular signal transduction and homeostasis. However, abnormal H2O2 regulation in live systems has been implicated in many pathological conditions. Monitoring this signal in live systems is essential but challenging because current H2O2 probes are impractical for efficient bio-imaging due to UV/visible light as the excitation source. We herein present a novel design based on an organic fluorophore-attached lanthanide-doped upconversion nanoprobe (CYD1-UCNPs) for selective UCL detection of H2O2. This nanoprobe represents the next-generation imaging tool that features a robust UCL "turn-on" response to H2O2 with NIR-excited ratiometric signals and has potential applications in ratiometric UCL imaging of endogenous H2O2 generating in living cells and whole-body animals.

NaF-mediated controlled-synthesis of multicolor Na(x)ScF(3+x):Yb/Er upconversion nanocrystals.

Synthesis of lanthanide-doped upconversion nanocrystals (LDUNs) with controlled morphology and luminescence has long been desired in order to fulfill various application requirements. In this work, we have investigated the effect of the NaF : Ln(3+) molar ratio, in the range of 1 to 20, on the morphology, crystal structure, and upconversion properties of NaxScF(3+x):Yb/Er nanocrystals that are reported to possess different upconversion properties from those of NaYF4:Yb/Er nanocrystals. The experimental results prove that the NaF : Ln(3+) molar ratio influences significantly the growth process of the nanocrystals, i.e. a low NaF : Ln(3+) molar ratio results in hexagonal NaScF4 nanocrystals, while a high NaF : Ln(3+) molar ratio favors monoclinic Na3ScF6 nanocrystals. When the NaF : Ln(3+) molar ratio is as high as 6 or above, phase separation is found and hexagonal NaYbF4 nanocrystals showed up for the first time. Simply by adjusting the NaF : Ln(3+) molar ratio, we have successfully achieved the simultaneous control of the shape, size, as well as the crystallographic phase of the NaxScF(3+x):Yb/Er nanocrystals, which give different red to green (R/G) ratios (integral area), leading to a multicolor upconversion luminescence from orange-red to green. This study provides a vivid example to track and interpret the formation mechanisms and growth processes of NaxScF(3+x):Yb/Er nanocrystals, which shall be instructive for guiding the controlled synthesis of other LDUNs and extending their according applications in optical communication, color display, anti-counterfeiting, bioimaging, and so on.

Inorganic-organic hybrid nanoprobe for NIR-excited imaging of hydrogen sulfide in cell cultures and inflammation in a mouse model.

Hydrogen sulfide (H2S) is an important gaseous signaling agent mediated by many physiological processes and diseases. In order to explore its role in biological signaling, much effort has been focused on developing organic fluorescent probes to image H2S. However, these downconversion H2S probes are impractical for bio-imaging beyond a certain depth because of the short tissue penetration of UV/visible light (as an excitation source). In most circumstance, these probes are also not suitable for long-term assay due to photo-bleaching. Herein, a new design to detect H2S based on the coumarin-hemicyanine (CHC1)-modified upconversion nanophosphors is reported. This inorganic-organic integrated nanoprobe is demonstrated to display a fast response time with a large ratiometric upconversion luminescence (UCL) enhancement, and extraordinary photo-stability. CHC1-UCNPs not only can be used for ratiometric UCL monitoring of pseudo-enzymatic H2S production in living cells, but can also be used to identify the risk of endotoxic shock through ratiometric UCL imaging of tissue and measurement of endogenous H2S levels in plasma. The first ratiometric UCL H2S nanoprobe reported here may be further developed as the next-generation diagnostic tool for the detection of inflammatory-related diseases.

Rhodamine-modified upconversion nanophosphors for ratiometric detection of hypochlorous acid in aqueous solution and living cells.

Hypochlorous acid (HOCl), a reactive oxygen species (ROS) produced by myeloperoxidase (MPO) enzyme-mediated peroxidation of chloride ions, acts as a key microbicidal agent in immune systems. However, misregulated production of HOCl could damage host tissues and cause many inflammation-related diseases. Due to its biological importance, many efforts have been focused on developing fluorescent probes to image HOCl in living system. Compared with those conventional fluorescent probes, up-conversion luminescence (UCL) detection system has been proven to exhibit a lot of advantages including no photo-bleaching, higher light penetration depth, no autofluorescence and less damage to biosamples. Herein, we report a novel water-soluble organic-nano detection system based on rhodamine-modified UCNPs for UCL-sensing HOCl. Upon the interaction with HOCl, the green UCL emission intensity in the detection system were gradually decreased, but the emissions in the NIR region almost have no change, which is very important for the ratiometric UCL detection of HOCl in aqueous solution. More importantly, RBH1-UCNPs could be used for the ratiometric UCL visualization of HOCl released by MPO-mediated peroxidation of chloride ions in living cells. This organic-nano system could be further developed into a novel next-generation imaging technique for bio-imaging HOCl in living system without background noise.

Orthorhombic KSc2F7:Yb/Er nanorods: controlled synthesis and strong red upconversion emission.

For the first time, we have synthesized orthorhombic phase KSc2F7:20%Yb/2%Er (KSc2F7:Yb/Er) nanorods and further studied the crystal structure and morphology evolution, as well as their upconversion (UC) properties under varying F(-) contents and reaction temperatures. Different from ß-NaYF4:20%Yb/2%Er (NaYF4:Yb/Er) nanorods that usually give strong green UC luminescence, strong red UC emission was observed in KSc2F7:Yb/Er nanorods under 980 nm laser excitation. Their UC mechanisms are further analyzed and compared. This study provides a novel type of rare earth nanorods with strong red UC emissions which have great potential in high resolution 3-dimensional bioimaging, color displays, solid-state lasers, and photocatalysis.

Enantioselective homocrotylboration of aliphatic aldehydes.

A practical route to optically pure syn-homocrotylation reagents is described, including highly diastereo- and enantioselective preparation of numerous syn-homocrotyl products, as well as several matched mismatched pairs. NMR experiments suggest that the active homocrotylating species is a cyclopropylcarbinyldichloroborane generated by chloride exchange from the PhBCl(2) activator. Computational studies support the intermediacy of chloroboranes and suggest that homoallyl/homocrotyl transfers occur through Zimmerman-Traxler transition states.

Observation of divergent isotope effects as well as metal ion-modulated T(C) and spin-canting nature in isostructural supramolecular magnets.

The ion-pair complexes of [4-NH(2)-PyH][M(mnt)(2)] (M = Pt for 1 and Ni for 3) and their deuterated analogues [4-NH(2)-PyD][M(mnt)(2)] (M = Pt for 2 and Ni for 4) are isostructural with each other. Four complexes crystalline in monoclinic space group C2/c, whose asymmetric unit consists of two halves of [M(mnt)(2)](-) anions and one cation, show quite similar cell parameters and almost identical packing structures as well. In the crystals of 1-4, two types of crystallographically inequivalent [M(mnt)(2)](-) anions construct individual layers, which are separated by the cation layer; the supramolecular networks are formed via the H-bonding interactions between the [M(mnt)(2)](-) and 4-NH(2)-PyH(+) (or 4-NH(2)-PyD(+)) ions as well as the weakly ππ stacking interactions between the [M(mnt)(2)](-) anions. The four isostructural complexes exhibit canted antiferromagnetism, arising from the non-collinearity of the magnetic moments between the crystallographically inequivalent anion layers, with T(C) ≈ 14.8 K for 1, 13.6 K for 2, 7.7 K for 3 and 8.8 K for 4, respectively. Ac magnetic susceptibility measurements revealed that 1 and 2 show spin canting, while 3 and 4 show hidden-spin canting characteristics. The isostructural 1 and 3 were deuterated to give the divergent isotope effects on the cell volume and T(C).

Observation of metal ion dependent packing structures and magnetic behaviors of metal-bis-1, 2-dithiolene complexes.

The crystal structures and magnetic properties were investigated experimentally and theoretically for two S = ½ spin chain complexes, which consist of [M(mnt)(2)](-) (M = Pt for 1 or Pd for 2) with 1-(4'-bromo-2'-flurobenzyl)-4-aminopyridinium (1-BrFBz-4-NH(2)Py(+)). The 1-BrFBz-4-NH(2)Py(+) cations exhibit different molecular conformations and arrangements in 1 and 2; the [M(mnt)(2)](-) anions form regular stacks in 1, whereas they form irregular stacks in 2. In addition, the intermolecular interactions between the [M(mnt)(2)](-) anions and cations are also different from each other in the crystals of 1 and 2. Complex 1 shows the magnetic characteristics of a low-dimensional antiferromagnetic coupling spin system with a spin-Peierls-type transition around 7 K, and complex 2 exhibits diamagnetism over the temperature range of 5-300 K. Theoretical analyses, based on the calculations for the charge density distributions of [Pt(mnt)(2)](-) and [Pd(mnt)(2)](-) anions and the magnetic exchange constants within the anion spin chains, addressed the diverse molecular alignments in the crystals of 1 and 2 and distinct magnetic behaviors between 1 and 2.

Homoallylboration and homocrotylboration of aldehydes.

A simple method for addition of homoallylic fragments to aldehydes is described. Cyclopropanated allylboration reagents react with aldehydes in the presence of PhBCl(2) to give high yields of bishomoallyl alcohols. Cyclopropanated cis- and trans-crotyl reagents afford the corresponding 1,3-anti- and 1,3-syn-methyl-substituted "homocrotylated" alcohols with high selectivity, consistent with a Zimmerman-Traxler transition state. Accordingly, the optically active α-substituted reactant affords the E-substituted product in 97:3 er.

Bis[1-(4-cyano-benz-yl)pyrazinium] bis-(1,2-dicyano-ethene-1,2-dithiol-ato)nickelate(II).

The asymmetric unit of the title complex, (C(12)H(10)N(3))(2)[Ni(C(4)N(2)S(2))(2)], consists of one 1-(4-cyano-benz-yl)pyrazinium cation and one half of an [Ni(mnt)(2)](2-) dianion (mnt(2-) is 1,2-dicyano-ethene-1,2-dithiol-ate). The Ni(2+) ion is located on an inversion center and is coordinated by four S atoms from two mnt(2-) ligands, exhibiting a square-planar coordination geometry. The cation adopts a conformation where both the pyrazine ring and the benzene ring are twisted with respect to the C-C-N reference plane by 16.5 (2) and 69.8 (1)°, respectively.

Bis(3,5,7-triaza-1-azoniatricyclo-[3.3.1.1]deca-ne) bis-(1,2-dicyano-ethene-1,2-dithiol-ato)nickelate(II).

The asymmetric unit of the title complex, (C(6)H(13)N(4))(2)[Ni(C(4)N(2)S(2))(2)], comprises one 1-azonia-3,5,7-triaza-tricyclo-[3.3.1.1(3,7)]decane cation and one half of an [Ni(mnt)(2)](2-) (mnt(2-) is maleonitrile-dithiol-ate or 1,2-dicyano-ethene-1,2-dithiol-ate) dianion. The Ni(2+) ion is located on a center of inversion and is coordinated by four S atoms from two mnt(2-) ligands in a square-planar coordination mode. Inter-molecular N-H⋯N hydrogen-bond inter-actions link one anion and two cations in the crystal structure.

Stack pattern of the countercation-modulating magnetic property of low-dimensional [Pt(mnt)2]⁻ monoanion spin systems.

Three [1-N-(4'-R-benzyl)-4-aminopyridinium][Pt(mnt)(2)] compounds were structurally and magnetically characterized, where the substituent was attached to the para-position of the phenyl ring (R = CN (1), Cl (2), and H (3); mnt(2-) = maleonitriledithiolate). 1 and 2 crystallized in the monoclinic space group P2(1)/c, with the cations and anions forming segregated columnar stacks. Their structural differences involved two aspects: (1) both anion and cation stacks were regular in 1 and irregular in 2; (2) the neighboring cations were arranged in the boat-type pattern in 1, whereas these cations were in the chair-type pattern in 2 within the cation stack. 3 belonged to the triclinic space group P ̅1, where the anions were assembled into the stack with a tetrameric [Pt(mnt)(2)](-) subunit, but the cations did not form the columnar stack. Magnetic measurements disclosed that a spin-Peierls-type transition occurred around 240 K for 1, whereas a long-range, antiferromagnetic ordering took place at about 5.8 K, and a metamagnetic phenomenon was observed with H(C) ≈ 1000 Oe for 2; 3 showed very strong antiferromagnetic interactions with diamagnetism in the temperature range 5-300 K. Combined with our previous studies, the correlation between the stacking pattern of benzylpyridinium derivatives in a cation stack and the spin-Peierls-type transition is discussed for the series of quasi-1-D [M(mnt)(2)](-) (M = Ni, Pd and Pt) compounds.