Synthesis of Imidazopyridinium-Fused Metallacycloallene via One-Pot Reaction of η²‑Alkynol-Coordinated Osmacycle with 2‑Aminopyridine

Metallacycloallenes are metallacyclic derivatives of cyclic allenes, in which a CH₂ (type <b>A</b>) or CH (type <b>B</b>) segment is formally replaced by an isolobal transition-metal fragment. In constrast to the well-developed chemistry of metallacycloallenes of type <b>A</b>, the synthesis of metallacycloallenes with the structural features of type <b>B</b> has met with limited success. In this study, we present the reaction of η²-alkynol-coordinated osmacycle <b>1</b> with 2-aminopyridine in the presence of hypervalent iodine reagent, leading to the formation of imidazopyridinium-fused 4-osmacyclohexa-2,3,5-trienone <b>2</b> and 4-osmacyclohexa-2,5-dienone <b>3</b>. Two key intermediates, η²-ethynyl ketone coordinated osmacycle <b>4</b> and 4-osmacyclohexa-2,5-dienone <b>5</b>, were isolated and fully characterized, which suggest the hypervalent iodine reagent plays an important role in the formation of the fused metallacycloallene <b>2</b>

Facile Synthesis of Hierarchical Networks Composed of Highly Interconnected V₂O₅ Nanosheets Assembled on Carbon Nanotubes and Their Superior Lithium Storage Properties

Hierarchical networks with highly interconnected V₂O₅ nanosheets (NSs) anchored on skeletons of carbon nanotubes (CNTs) are prepared by a facile hydrothermal treatment and a following calcination for the first time. Benefiting from these unique structural features, the as-prepared CNT@V₂O₅ material shows dramatically excellent electrochemical performance with remarkable long cyclability (137–116 mA h g^–1 after 400 cycles) at various high rates (20 C to 30 C) and very good rate capability for highly reversible lithium storage. The excellent electrochemical performance suggests its promising use as a cathode material for future lithium-ion batteries

Synthesis and Characterization of an Osmapentalene Derivative Containing a β‑Agostic Os···H–C(sp³) Interaction

Treatment of cyclopropaosmapentalene (<b>1</b>) with EtCCEt in the presence of AgBF₄ gave a new type of polycyclic metallaaromatic complex with a structure containing an sp³ carbon and a β-agostic Os···H–C­(sp³) interaction. This result strongly supported our proposed intermediate in the reaction of cyclopropaosmapentalene <b>1</b> with alkynes that produced photothermal osmium carbolong complexes. When EtCCCOMe was used, the reaction gave a more thermally stable ketone-coordinated complex as the major product. The DFT study indicated that the difference in the two reactions is of thermodynamic origin

Color-Tuning Strategy for Iridapolycycles [(N^∧N)Ir(C^∧C)ClPPh₃]⁺ by the Synergistic Modifications on Both the C^∧C and N^∧N Units

The luminescent studies of cyclometalated Ir­(III) complexes have attracted considerable interests in recent years. To fulfill the needs of emission wavelengths in various areas, the strategic emission color tuning of iridium­(III) complexes is vital for their applications as phosphorescent materials. However, a feasible color-tuning method for iridacycles with fused carbon-rings (C^∧C) has not been reported yet. Herein, a convenient color-tuning strategy for C^∧C-based Iridacycles is accomplished with the aid of DFT calculations. The developed synthetic protocol allowed facile modifications on C^∧C units and N^∧N units via a one-pot synthesis starting from iridium vinyl complexes, accessing the novel phosphorescent iridapolycycles [(N^∧N)­Ir­(C^∧C)­ClPPh₃]⁺

História Unisinos

A facile bottom-up method is reported here for the fabrication of N-doped graphene for oxygen reduction. It consists of a two-step calcination strategy and uses α-hydroxy acids (AHAs) as carbon source and melamine as nitrogen source. Three different AHAs, malic acid, tartaric acid, and citric acid, were chosen as the carbon sources. The prepared N-doped graphenes have a typical thin layered structure with a large specific surface area. It was found that the N content in the obtained N-doped graphenes varies from 4.12 to 8.11 at. % depending on the AHAs used. All of the samples showed high performance in oxygen reduction reaction (ORR). The N-doped graphene prepared from citric acid demonstrated the highest electrocatalytic activity, which is comparable to the commercial Pt/C and exhibited good durability, attributing to the high pyridinic N content in the composite

Coupled Chiral Structure in Graphene-Based Film for Ultrahigh Thermal Conductivity in Both In-Plane and Through-Plane Directions

The development of high-performance thermal management materials to dissipate excessive heat both in plane and through plane is of special interest to maintain efficient operation and prolong the life of electronic devices. Herein, we designed and constructed a graphene-based composite film, which contains chiral liquid crystals (cellulose nanocrystals, CNCs) inside graphene oxide (GO). The composite film was prepared by annealing and compacting of self-assembled GO-CNC, which contains chiral smectic liquid crystal structures. The helical arranged nanorods of carbonized CNC act as in-plane connections, which bridge neighboring graphene sheets. More interestingly, the chiral structures also act as through-plane connections, which bridge the upper and lower graphene layers. As a result, the graphene-based composite film shows extraordinary thermal conductivity, in both in-plane (1820.4 W m^–1 K^–1) and through-plane (4.596 W m^–1 K^–1) directions. As a thermal management material, the heat dissipation and transportation behaviors of the composite film were investigated using a self-heating system and the results showed that the real-time temperature of the heater covered with the film was 44.5 °C lower than a naked heater. The prepared film shows a much higher efficiency of heat transportation than the commonly used thermal conductive Cu foil. Additionally, this graphene-based composite film exhibits excellent mechanical strength of 31.6 MPa and an electrical conductivity of 667.4 S cm^–1. The strategy reported here may open a new avenue to the development of high-performance thermal management films

Reactions of Osmium Hydrido Alkenylcarbyne with Allenoates: Insertion and [3 + 2] Annulation

Treatment of the osmium hydrido alkenylcarbyne complex [OsH­{CC­(PPh₃)CHPh}­(PPh₃)₂Cl₂]­BF₄ (<b>1</b>) with allenoates (CH₂CCHCOOR, R = Me, Et) in the presence of excess AgBF₄ leads to the insertion products <b>2</b>/<b>3</b>. The reactions of complex <b>1</b> with substituted allenoates, i.e., diethyl 2-vinylidenesuccinate (CH₂CC­(CH₂COOEt)­(COOEt)) and ethyl penta-2,3-dienoate (CH­(CH₃)CCH­(COOEt)), result in the formation of [3 + 2] annulation products <b>4</b> and <b>6</b>, respectively. Mechanisms of the reactions have been proposed with the isolation of the key intermediates. The results reveal that the divergent pathways for these reactions are mainly of steric origin

Additional file 1: of Secreted protein acidic and rich in cysteine-like 1 suppresses metastasis in gastric stromal tumors

Figure S1. Volcano plots of differential expression proteins. The vertical lines correspond to 2.0-fold up and down, respectively, and the horizontal line represents a p-value of 0.05. The red point in the plot represents the differentially protein with statistically significance. (A: gastric GIST with LGM; B: gastric GIST with HGM; C: corresponding adjacent normal tissues for LGM; D: corresponding adjacent normal tissues for HGM). (JPG 751 kb

Electrospun P2-type Na_2/3(Fe_1/2Mn_1/2)O₂ Hierarchical Nanofibers as Cathode Material for Sodium-Ion Batteries

Sodium-ion batteries can be the best alternative to lithium-ion batteries, because of their similar electrochemistry, nontoxicity, and elemental abundance and the low cost of sodium. They still stand in need of better cathodes in terms of their structural and electrochemical aspects. Accordingly, the present study reports the first example of the preparation of Na_2/3(Fe_1/2Mn_1/2)­O₂ hierarchical nanofibers by electrospinning. The nanofibers with aggregated nanocrystallites along the fiber direction have been characterized structurally and electrochemically, resulting in enhanced cyclability when compared to nanoparticles, with initial discharge capacity of ∼195 mAh g^–1. This is attributed to the good interconnection among the fibers, with well-guided charge transfers and better electrolyte contacts

Natural immunity and cell growth regulation

A carbon/SnO₂ composite (C-SnO₂) with hierarchical photonic structure was fabricated from the templates of butterfly wings. We have investigated for the first time its application as the anode material for lithium-ion batteries. It was demonstrated to have high reversible capacities, good cycling stability, and excellent high-rate discharge performance, as shown by a capacitance of ∼572 mAh g^–1 after 100 cycles, 4.18 times that of commercial SnO₂ powder (137 mAh g^–1); a far better recovery capability of 94.3% was observed after a step-increase and sudden-recovery current. An obvious synergistic effect was found between the porous, hierarchically photonic microstructure and the presence of carbon; the synergy guarantees an effective flow of electrolyte and a short diffusion length of lithium ions, provides considerable buffering room, and prevents aggregation of SnO₂ particles in the discharge/charge processes. This nature-inspired strategy points out a new direction for the fabrication of alternative anode materials