Ratiometric dual-emission of Rhodamine-B grafted carbon dots for full-range solvent components detection.

Quick and visual detection of component contents, such as water, in a mixed solvent is important for many practical applications, and a full range detection is especially preferred. In this work, a carbon dots based ratiometric fluorescent sensor was synthesized by grafting fluorescent group (Rhodamine B, RhB) on carbon dots, and the dual emission peaks exhibited a linear ratiometric response with the change of polarity and hydrogen bond of Solvent Hansen solubility parameters. This responsive behavior is attributed to surface state photoluminescence mechanisms, and has been used for the quantitative detection of water content in ethanol with an excellent linear relationship (R = 0.

Interface-Controlled Thermal Rectification Phenomenon of Monolayer Graphene/Boron Nitride Heterosheet.

Thermal rectification (TR) in graphene/boron nitride (GBN) monolayer heterosheets containing various types of interfacial structures has been studied using molecular dynamic simulations. The TR effect is ascribed to the asymmetric heat flow caused by mismatched PDOS of graphene and BN in the boundary. Additionally, the dependences of TR effects on boundary structures and defects are discussed.

Synthesis of i-Corona[6]arenes for Selective Anion Binding: Interdependent and Synergistic Anion-π and Hydrogen-Bond Interactions.

i-Corona[3]arene[3]tetrazines were synthesized from the nucleophilic aromatic substitution reaction of resorcinol and its derivatives with 3,6-dichlorotetrazine in a one-pot fashion under mild conditions. All of the resulting macrocycles adopted 1,3,5-alternate conformation irrespective of the nature of the substituents on both upper- and lower-rims. i-Corona[3]arene[3]tetrazine was found to self-regulate its macrocyclic conformation and cavity to recognize anions with binding constants spanning from 26 M to 2.

Exceptional high thermal conductivity of inter-connected annular graphite structures.

Based on the experimentally observed templating effects in CNTs containing carbon fibers, new types of inter-connected annular graphite structures are proposed and designed in order to significantly improve the cross-plane thermal conductivity of graphite. The calculations of the thermal conductivity of the newly designed structures were carried out by combining macroscopic continuous equations and microscopic molecular dynamic (MD) simulations. First, MD simulation was used to examine the influence of bending curvature on the in-plane thermal conductivity of a graphene sheet along and perpendicular to the rolling direction.

Photoredox Catalysis: Construction of Polyheterocycles via Alkoxycarbonylation/Addition/Cyclization Sequence.

A novel visible-light-induced cascade reaction for the preparation of ester-functionalized polyheterocycles was developed under metal-free conditions, which was initiated by an intermolecular radical addition to a carbon-carbon double bond of N-arylacrylamide derivatives using alkyl carbazate as the ester source followed by cyano-mediated cyclization. The desired phenanthridine derivative products were isolated in moderate to high yields with broad substrate scope.

Addition of nitrogen dioxide to carbon-carbon double bond followed by a cyclization to construct nitromethylated isoquinolinediones.

Heterocyclic derivatives 4-(nitromethyl)isoquinoline-1,3(2H,4H)-diones were synthesized via a tandem nitration/cyclization reaction of N-alkyl-N-methacryloyl benzamides under metal-free conditions. The cheap and available reagent nitrogen dioxide was used as the nitro source, as well as the oxidant. For the substrates with various substituent groups, the reaction proceeded smoothly to give the corresponding isoquinolinedione derivatives in moderate to good yields.

Cyanomethylation and Cyclization of Aryl Alkynoates with Acetonitrile under Transition-Metal-Free Conditions: Synthesis of 3-Cyanomethylated Coumarins.

Cyanomethylated coumarins were synthesized via cyanomethylation and cyclization of aryl alkynoates using cheap and available reagent acetonitrile as the cyanomethyl source in the presence of TBPB (tert-butyl peroxybenzoate) under transition-metal-free conditions. For the substrates with various substituents on benzene ring, the reaction proceeded smoothly to give the corresponding products in moderate to good yields. The resulting products could be simply converted into some other related coumarin derivatives.

DFT study of the effects of interstitial impurities on the resistance of Cr-doped γ-Fe(111) surface dissolution corrosion.

Using density-functional calculations, we studied the interaction between interstitial impurities (N, C) and γ-Fe(111) surfaces doped, or not, with Cr, as well as the effect of Cr doping on the dissolution corrosion resistance of the γ-Fe(111) surface. The elementary processes studied afforded microscopic insights into the formation of a Cr-depleted zone, a phenomenon that leads to local corrosion of the stainless steel surface. The aim of this work was to study, at the atomic scale, the effects of N and C on the segregation behavior of Cr and the synergetic effect between co-doped atoms on the resistance to dissolution corrosion of austenitic stainless steel surfaces.

Effects of alloying on oxidation and dissolution corrosion of the surface of γ-Fe(111): a DFT study.

Effects of alloying elements in popular steels on the oxidation and dissolution corrosion of the surface of γ-Fe(111) have been investigated by performing density functional theory calculations within the local density approximation. First, the segregation of alloying atoms as well as preferential adsorption sites for oxygen and water were carefully examined, and it was found that all of the alloying elements considered had a tendency to segregate to the surface, and that the most preferred adsorption sites were the hexagonal closed packed (hcp) site and the top site for oxygen and water, respectively. The adsorption energies that characterized the tendency for oxygen or water to be adsorbed on the alloy surface showed that all ten alloying elements (especially Cr, Si, and Cu) were able to inhibit the adsorption of oxygen, and that all of the alloying elements except for Nb, Mo, and Ti inhibited water adsorption.

Metallofullerenes encaging mixed-metal clusters: synthesis and structural studies of Gdx Ho3-x N@C80 and Gdx Lu3-x N@C80.

Metallofullerenes of Gdx Ho3-x N@C80 and Gdx Lu3-x N@C80 encapsulating mixed-metal nitride clusters were synthesized. Spectroscopic characterization of Gdx Ho3-x N@C80 and Gdx Lu3-x N@C80 was employed to reveal their structural and vibrational properties. The structural properties of these species were analyzed by using theoretical calculations.