Chemistry - A European Journal,
Год журнала:
2022,
Номер
28(29)
Опубликована: Март 18, 2022
Hydrodefluorination
(HDF)
is
a
very
important
fundamental
transformation
for
conversion
of
the
C-F
bond
into
C-H
in
organic
synthesis.
In
past
decade,
much
progress
has
been
achieved
with
HDF
through
utility
low-valent
metals,
transition-metal
complexes
and
main-group
Lewis
acids.
Recently,
novel
methods
have
introduced
this
purpose
photo-
electrochemical
pathways,
which
are
great
significance,
due
to
their
considerable
environmental
economical
advantages.
This
Review
highlights
fluorinated
compounds
(FOCs)
strategies,
along
mechanistic
insights.
Chemical Reviews,
Год журнала:
2021,
Номер
122(2), С. 2487 - 2649
Опубликована: Ноя. 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.
JACS Au,
Год журнала:
2021,
Номер
1(11), С. 1860 - 1876
Опубликована: Сен. 24, 2021
Precious
and
rare
elements
have
traditionally
dominated
inorganic
photophysics
photochemistry,
but
now
we
are
witnessing
a
paradigm
shift
toward
cheaper
more
abundant
metals.
Even
though
emissive
complexes
based
on
selected
first-row
transition
metals
long
been
known,
recent
conceptual
breakthroughs
revealed
that
much
broader
range
of
in
different
oxidation
states
useable
for
this
purpose.
Coordination
compounds
V,
Cr,
Mn,
Fe,
Co,
Ni,
Cu
show
electronically
excited
with
unexpected
reactivity
photoluminescence
behavior.
Aside
from
providing
compact
survey
the
key
advances
dynamic
field,
our
Perspective
identifies
main
design
strategies
enabled
discovery
fundamentally
new
types
3d-metal-based
luminophores
photosensitizers
operating
solution
at
room
temperature.
Journal of the American Chemical Society,
Год журнала:
2021,
Номер
143(29), С. 10882 - 10889
Опубликована: Июль 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,
Год журнала:
2021,
Номер
143(33), С. 13266 - 13273
Опубликована: Авг. 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.
Nature Chemistry,
Год журнала:
2023,
Номер
15(12), С. 1730 - 1736
Опубликована: Авг. 14, 2023
Coordination
complexes
of
precious
metals
with
the
d6
valence
electron
configuration
such
as
Ru(II),
Os(II)
and
Ir(III)
are
used
for
lighting
applications,
solar
energy
conversion
photocatalysis.
Until
now,
made
from
abundant
first-row
transition
competitive
photophysical
photochemical
properties
have
been
elusive.
While
previous
research
efforts
focused
mostly
on
Fe(II),
we
disclose
that
isoelectronic
Cr(0)
gives
access
to
higher
photoluminescence
quantum
yields
excited-state
lifetimes
when
compared
any
other
metal
complex
reported
so
far.
The
luminescence
behaviour
metal-to-ligand
charge
transfer
excited
states
these
is
polypyridines.
With
complexes,
become
exploitable
in
photoredox
catalysis,
benchmark
chemical
reductions
proceed
efficiently
under
low-energy
red
illumination.
Here
demonstrate
appropriate
molecular
design
strategies
open
up
new
perspectives
photophysics
photochemistry
metals.
Angewandte Chemie International Edition,
Год журнала:
2021,
Номер
60(39), С. 21418 - 21425
Опубликована: Июль 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.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(22), С. 9859 - 9873
Опубликована: Май 27, 2022
Many
organometallic
iridium(III)
complexes
have
photoactive
excited
states
with
mixed
metal-to-ligand
and
intraligand
charge
transfer
(MLCT/ILCT)
character,
which
form
the
basis
for
numerous
applications
in
photophysics
photochemistry.
Cobalt(III)
analogous
MLCT
excited-state
properties
seem
to
be
unknown
yet,
despite
fact
that
cobalt(III)
can
adopt
identical
low-spin
d6
valence
electron
configurations
due
their
close
chemical
relationship.
Using
a
rigid
tridentate
chelate
ligand
(LCNC),
central
amido
π-donor
is
flanked
by
two
σ-donating
N-heterocyclic
carbene
subunits,
we
obtained
robust
homoleptic
complex
[Co(LCNC)2](PF6),
featuring
state
substantial
character.
Compared
vast
majority
of
isoelectronic
iron(II)
complexes,
[Co(LCNC)2](PF6)
long-lived
because
it
does
not
deactivate
as
efficiently
into
lower-lying
metal-centered
states;
furthermore,
engages
directly
photoinduced
reactions.
The
comparison
[Fe(LCNC)2](PF6),
well
structural,
electrochemical,
UV–vis
transient
absorption
studies,
provides
insight
new
design
principles
first-row
transition-metal
photophysical
photochemical
reminiscent
those
known
from
platinum
group
metals.
Chemical Science,
Год журнала:
2021,
Номер
12(29), С. 9922 - 9933
Опубликована: Янв. 1, 2021
A
full
picture
of
a
new
multi-photon
excitation
mechanism
relying
on
sTTA
upconversion
is
provided,
together
with
selected
photocatalytic
applications.
All
mechanistic
steps
are
investigated
and
the
catalytically
active
species
observed
directly.
Journal of the American Chemical Society,
Год журнала:
2022,
Номер
144(2), С. 963 - 976
Опубликована: Янв. 5, 2022
Cyclometalated
Ir(III)
complexes
are
often
chosen
as
catalysts
for
challenging
photoredox
and
triplet-triplet-energy-transfer
(TTET)
catalyzed
reactions,
they
of
interest
upconversion
into
the
ultraviolet
spectral
range.
However,
triplet
energies
commonly
employed
photosensitizers
typically
limited
to
values
around
2.5-2.75
eV.
Here,
we
report
on
a
new
luminophore,
with
an
unusually
high
energy
near
3.0
eV
owing
modification
previously
reported
complex
isocyanoborato
ligands.
Compared
nonborylated
cyanido
precursor
complex,
introduction
B(C6F5)3
units
in
second
coordination
sphere
results
substantially
improved
photophysical
properties,
particular
luminescence
quantum
yield
(0.87)
long
excited-state
lifetime
(13.0
μs),
addition
energy.
These
favorable
properties
(including
good
long-term
photostability)
facilitate
exceptionally
organic
photoreactions
(sensitized)
triplet-triplet
annihilation
fluorescent
singlet
excited
state
beyond
4
eV,
deep
region.
The
photocatalyzes
sigmatropic
shift
[2
+
2]
cycloaddition
reactions
that
unattainable
common
transition
metal-based
photosensitizers.
In
presence
sacrificial
electron
donor,
it
furthermore
is
applicable
demanding
photoreductions,
including
dehalogenations,
detosylations,
degradation
lignin
model
substrate.
Our
study
demonstrates
how
rational
ligand
design
transition-metal
underexplored
effects)
can
be
used
enhance
their
thereby
broaden
application
potential
solar
conversion
synthetic
photochemistry.