Orientation-dependent micromechanical behavior of nacre: In situ TEM experiments and finite element simulations.

Nacre's superior mechanical properties and failure behavior are strongly orientation-dependent due to its brick-and-mortar microstructure. In this work, the anisotropic microscopic deformation and the resulting macroscopic mechanical properties are evaluated under different loading conditions. Our in situ transmission electron microscopy deformation experiments and finite element simulations reveal that nacre possesses enhanced indentation resistance along the direction normal to the tablets through delocalization of indentation-induced deformation by taking advantage of its layered structure.

Gradient Crystal Plasticity: A Grain Boundary Model for Slip Transmission.

Interaction between dislocations and grain boundaries (GBs) in the forms of dislocation absorption, emission, and slip transmission at GBs significantly affects size-dependent plasticity in fine-grained polycrystals. Thus, it is vital to consider those GB mechanisms in continuum plasticity theories. In the present paper, a new GB model is proposed by considering slip transmission at GBs within the framework of gradient polycrystal plasticity.

Cu-Catalyzed Three-Component Coupling of Aryne, Alkyne, and Benzenesulfonothioate: Modular Synthesis of o-Alkynyl Arylsulfides.

A copper-catalyzed three-component coupling reaction of in situ formed arynes, terminal alkynes, and benzenesulfonothioates is described. This reaction provides an efficient modular synthesis of o-alkynyl arylsulfides from easily available starting materials. This process involves one C-S bond and one C-C bond formation in one pot.

Copper(I)-Catalyzed Interrupted Click Reaction: Synthesis of Diverse 5-Hetero-Functionalized Triazoles.

The 5-heterofunctionalized triazoles are important scaffolds in bioactive compounds, but current click reactions (CuAAC) cannot produce these core structures. A copper(I)-catalyzed interrupted click reaction to access diverse 5-functionalized triazoles is reported. Various 5-amino-, thio-, and selenotriazoles were readily assembled in one step in high yields.

Synthesis of quinolinones with palladium-catalyzed oxidative annulation between acrylamides and arynes.

An unprecedented palladium-catalyzed oxidative annulation of acrylamides with benzyne precursors has been successfully developed. By using this mild "N-H activation/Heck reaction" method, a wide variety of quinolinones were conveniently prepared in one step with high efficiency.

Strain-promoted oxidative annulation of arynes and cyclooctynes with benzamides: palladium-catalyzed C-H/N-H activation for the synthesis of N-heterocycles.

Strained alkynes include arynes and cyclooctynes reacted with N-methoxyamides through palladium-catalyzed C-H/N-H activation for the first time. A variety of important N-heterocycles such as phenanthridinones and isoquinolones were constructed in one step with high efficiency.

Dimerization of cyclopropenes to bifurans using tandem metal relay catalysis.

An efficient synthesis of bifurans via dimerization of cyclopropenes has been successfully developed using a copper-promoted cycloisomerization and palladium-catalyzed dimerization cascade. These novel bifuran structures possess interesting optoelectronic properties.

Modular synthesis of all-substituted furans through oxidative carbonylation of cyclopropenes with tandem metal relay catalysis.

A modular synthesis of tetrasubstituted furan carboxylates using a tandem cycloisomerization/oxidative carbonylation sequence of cyclopropenes has been successfully developed. The Tandem Metal Relay Catalysis (TMRC) pathway accounted for the high efficiency of this transformation.