Abstract
Understanding photocatalysis requires knowledge of the primary and secondary photophysical
and photochemical processes: light absorption and emission, radiationless decay, energy
and electron transfer, and hydrogen and group transfer. Photocatalysis is largely
dictated by energy and spin restrictions that allow fast transfer of energy, electrons,
or atoms. The kinetics of photoredox-initiated catalysis can be estimated from the
redox properties of the electronic ground states as well as the excitation energies
and spin properties of the excited states involved. These principles are demonstrated
using three model processes: photochemical decarboxylation, fluorination/fluoroalkylation,
and (molecular) oxygen-transfer processes.
