Chemical Science,
Journal Year:
2022,
Volume and Issue:
13(32), P. 9165 - 9175
Published: Jan. 1, 2022
An
iron
complex
with
N-heterocyclic
carbene
ligands
engages
in
efficient
photoredox
catalysis
via
excited
state
electron
transfer
reactions
of
its
Fe(
ii
)
and
iii
oxidation
states.
Chemical Reviews,
Journal Year:
2021,
Volume and Issue:
122(2), P. 2487 - 2649
Published: Nov. 9, 2021
Redox
processes
are
at
the
heart
of
synthetic
methods
that
rely
on
either
electrochemistry
or
photoredox
catalysis,
but
how
do
and
catalysis
compare?
Both
approaches
provide
access
to
high
energy
intermediates
(e.g.,
radicals)
enable
bond
formations
not
constrained
by
rules
ionic
2
electron
(e)
mechanisms.
Instead,
they
1e
mechanisms
capable
bypassing
electronic
steric
limitations
protecting
group
requirements,
thus
enabling
chemists
disconnect
molecules
in
new
different
ways.
However,
while
providing
similar
intermediates,
differ
several
physical
chemistry
principles.
Understanding
those
differences
can
be
key
designing
transformations
forging
disconnections.
This
review
aims
highlight
these
similarities
between
comparing
their
underlying
principles
describing
impact
electrochemical
photochemical
methods.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(29), P. 10882 - 10889
Published: July 13, 2021
We
describe
a
photocatalytic
system
that
elicits
potent
photoreductant
activity
from
conventional
photocatalysts
by
leveraging
radical
anion
intermediates
generated
in
situ.
The
combination
of
an
isophthalonitrile
photocatalyst
and
sodium
formate
promotes
diverse
aryl
coupling
reactions
abundant
but
difficult
to
reduce
chloride
substrates.
Mechanistic
studies
reveal
two
parallel
pathways
for
substrate
reduction
both
enabled
key
terminal
reductant
byproduct,
carbon
dioxide
anion.
Journal of the American Chemical Society,
Journal Year:
2021,
Volume and Issue:
143(33), P. 13266 - 13273
Published: Aug. 16, 2021
Since
the
seminal
work
of
Zhang
in
2016,
donor–acceptor
cyanoarene-based
fluorophores,
such
as
1,2,3,5-tetrakis(carbazol-9-yl)-4,6-dicyanobenzene
(4CzIPN),
have
been
widely
applied
photoredox
catalysis
and
used
excellent
metal-free
alternatives
to
noble
metal
Ir-
Ru-based
photocatalysts.
However,
all
reported
reactions
involving
this
chromophore
family
are
based
on
harnessing
energy
from
a
single
visible
light
photon,
with
limited
range
redox
potentials
−1.92
+1.79
V
vs
SCE.
Here,
we
document
unprecedented
discovery
that
fluorophores
can
undergo
consecutive
photoinduced
electron
transfer
(ConPET)
achieve
very
high
reduction
potentials.
One
newly
synthesized
catalysts,
2,4,5-tri(9H-carbazol-9-yl)-6-(ethyl(phenyl)amino)isophthalonitrile
(3CzEPAIPN),
possesses
long-lived
(12.95
ns)
excited
radical
anion
form,
3CzEPAIPN•–*,
which
be
activate
reductively
recalcitrant
aryl
chlorides
(Ered
≈
−1.9
−2.9
SCE)
under
mild
conditions.
The
resultant
radicals
engaged
synthetically
valuable
aromatic
C–B,
C–P,
C–C
bond
formation
furnish
arylboronates,
arylphosphonium
salts,
arylphosphonates,
spirocyclic
cyclohexadienes.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
61(12)
Published: Sept. 3, 2021
Synthetic
photoelectrochemistry
(PEC)
is
receiving
increasing
attention
as
a
new
frontier
for
the
generation
and
handling
of
reactive
intermediates.
PEC
permits
selective
single-electron
transfer
(SET)
reactions
in
much
greener
way
broadens
redox
window
possible
transformations.
Herein,
most
recent
contributions
are
reviewed,
demonstrating
exciting
opportunities,
namely,
combination
with
other
reactivity
paradigms
(hydrogen-atom
transfer,
radical
polar
crossover,
energy
sensitization),
scalability
up
to
multigram
scale,
novel
selectivities
SET
super-oxidations/reductions
importance
precomplexation
temporally
enable
excited
ion
catalysis.
Science,
Journal Year:
2022,
Volume and Issue:
376(6592), P. 527 - 532
Published: April 28, 2022
Discovery
chemists
routinely
identify
purpose-tailored
molecules
through
an
iterative
structural
optimization
approach,
but
the
preparation
of
each
successive
candidate
in
a
compound
series
can
rarely
be
conducted
manner
matching
their
thought
process.
This
is
because
many
necessary
chemical
transformations
required
to
modify
cores
straightforward
fashion
are
not
applicable
complex
contexts.
We
report
method
that
addresses
one
facet
this
problem
by
allowing
hop
directly
between
chemically
distinct
heteroaromatic
scaffolds.
Specifically,
we
show
selective
photolysis
quinoline
JACS Au,
Journal Year:
2025,
Volume and Issue:
5(2), P. 426 - 447
Published: Jan. 29, 2025
Many
important
synthetic-oriented
works
have
proposed
excited
organic
radicals
as
photoactive
species,
yet
mechanistic
studies
raised
doubts
about
whether
they
can
truly
function
photocatalysts.
This
skepticism
originates
from
the
formation
of
(photo)redox-active
degradation
products
and
picosecond
decay
electronically
radicals,
which
is
considered
too
short
for
diffusion-based
photoinduced
electron
transfer
reactions.
From
this
perspective,
we
analyze
synthetic
transformations
where
been
photocatalysts,
comparing
their
theoretical
maximum
state
potentials
with
required
observed
photocatalytic
reactivity.
We
summarize
structurally
similar
photocatalysts
indicating
different
reaction
pathways
some
catalytic
systems,
addressing
cases
radical
exceed
Additionally,
perform
a
kinetic
analysis
to
explain
in
on
subpicosecond
time
scales.
further
rationalize
potential
anti-Kasha
reactivity
higher
states
femtosecond
lifetimes,
highlighting
how
future
photocatalysis
advancements
could
unlock
new
photochemical
pathways.
Angewandte Chemie International Edition,
Journal Year:
2021,
Volume and Issue:
60(39), P. 21418 - 21425
Published: July 20, 2021
Herein,
we
disclose
that
electrochemical
stimulation
induces
new
photocatalytic
activity
from
a
range
of
structurally
diverse
conventional
photocatalysts.
These
studies
uncover
electron-primed
photoredox
catalyst
capable
promoting
the
reductive
cleavage
strong
C(sp2
)-N
and
)-O
bonds.
We
illustrate
several
examples
synthetic
utility
these
deeply
reducing
but
otherwise
safe
mild
catalytic
conditions.
Finally,
employ
current
measurements
to
perform
reaction
progress
kinetic
analysis.
This
technique
reveals
improved
this
system
is
consequence
an
enhanced
stability
profile.