RESUMEN
A silver-catalyzed intramolecular radical relay cyclization of α-imino-oxy acids under mild conditions has been described. This reaction offers facile access to a diverse range of fused tetralone derivatives with exquisite stereoselectivity in moderate to good yields (40-98%). Experimental studies show that the reaction undergoes a decarboxylation and acetone fragmentation/1,5-hydrogen atom transfer (HAT)/cyclization process.
RESUMEN
2D Si nanomaterials have attracted tremendous attention due to their novel properties and a wide range of potential applications from electronic devices to energy storage and conversion. However, high-quality and large-scale fabrication of 2D Si remains challenging. This study reports a room-temperature and one-step synthesis technique that leads to large-scale and low-cost production of Si nanosheets (SiNSs) with thickness ≈4 nm and lateral size of several micrometers, based on the intrinsic delithiation process of chemically leaching lithium from the Li13 Si4 alloy. Together with experimental results, a combination of theoretical modeling and atomistic simulations indicates that the formation of single SiNS arises from spontaneous delamination of nanosheets from their substrate due to delithiation-induced mismatch. Subsequently, the synthesized Si nanosheets evolve from amorphous to nanocrystalline to crystalline structures during annealing at different temperatures. It is demonstrated that these SiNSs possess unique mechanical properties, in particular ultralow friction, in contrast to their bulk counterparts.
RESUMEN
Lithium-ion batteries with a Si anode can drive large mechanical actuation by utilizing the dramatic volume changes of the electrode during the charge/discharge cycles. A large loading of more than 10 MPa can be actuated by a LiFePO4 ||Si full battery with a rapid response while the driving voltage is lower than 4 V.
