We report a facile synthesis of carbon quantum dot (CQD)-sensitized TiO 2 /Pt nanocomposites as efficient and robust photocatalysts for light-driven proton reduction from water. We show that this method not only simplifies the synthetic procedure for such hybrid materials but also enhances the direct interaction between CQDs and TiO 2 , which facilitates charge transfer from CQDs to TiO 2 and eventually improves its performance for light-driven H 2 generation. To the best of our knowledge, this work represents the system with highest H 2 generation efficiency among all CQD-sensitized materials.
The dual function of the N À Fb ond as an effective oxidant and subsequent nitrogen source in intramolecular aliphatic C À Hfunctionalization reactions is explored. Copper catalysis is demonstrated to exercise full regio-and chemoselectivity control, whicho pens new synthetic avenues to nitrogenated heterocycles with predictable ring sizes.F or the first time,auniform catalysis manifold has been identified for the construction of both pyrrolidine and piperidine cores.The individual steps of this new copper oxidation catalysis were elucidated by control experiments and computational studies, clarifying the singularity of the NÀFf unction and characterizing the catalytic cycle to be based on acopper(I/II) manifold.
A method
for site-selective intermolecular δ/ε-Csp
3–H cyanation of aliphatic sulfonamides
is developed using TsCN as the cyanating reagent, catalyzed by a Cu(I)/phenanthroline
complex. The mild, expeditious, and modular protocol allows efficient
remote Csp
3–H cyanation with good functional
group tolerance and high regioselectivity. Mechanistic studies indicate
that the reaction might proceed through a Cu(I)-mediated N–F
bond cleavage to generate an amidyl radical, 1,5-HAT, and cyano group
transfer of the resulting carbon radical with TsCN.
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