Polymeric
graphitic carbon nitride materials have attracted significant interest in
recent years and found applications in diverse light-to-energy conversions such
as artificial photosynthesis, CO<sub>2 </sub>reduction or degradation of
organic pollutants. However, their utilization in synthetic photocatalysis especially
in the direct functionalization of C(sp<sup>3</sup>)−H bonds remains
underexplored. Herein, we report mesoporous graphitic carbon nitride (mpg-CN)
as a heterogeneous organic semiconductor photocatalyst for direct arylation of
sp<sup>3</sup> C−H bonds <i>via </i>a combination of<i> </i>hydrogen atom
transfer and nickel catalysis. Our protocol has a broad synthetic scope (>70
examples including late-stage modification of densely functionalized bio-active
molecules), is operationally simple, and shows high chemo- and
regioselectivity. Facile separation and recycling of the mpg-CN catalyst in
combination with its low preparation cost, innate photochemical stability and
low toxicity are beneficial features overcoming typical shortcomings of
homogeneous photocatalysis. Additionally, mechanistic investigations indicate
that an unprecedented energy transfer process (EnT) from the organic
semiconductor to the nickel complex is operating.
High mobility organic semiconductor for constructing high efficiency carbon nitride heterojunction photocatalysts