Journal of the American Chemical Society,
Год журнала:
2021,
Номер
143(25), С. 9332 - 9337
Опубликована: Июнь 15, 2021
Here
we
report
the
use
of
pulse
radiolysis
and
spectroelectrochemistry
to
generate
low-valent
nickel
intermediates
relevant
synthetically
important
Ni-catalyzed
cross-coupling
reactions
interrogate
their
reactivities
toward
comproportionation
oxidative
addition
processes.
Pulse
provided
a
direct
means
singly
reduced
[(dtbbpy)NiBr],
enabling
identification
rapid
Ni(0)/Ni(II)
process
taking
place
under
electrolysis
conditions.
This
approach
also
permitted
measurement
Ni(I)
rates
with
electronically
differentiated
aryl
iodide
electrophiles
(kOA
=
1.3
×
104–2.4
105
M–1
s–1),
an
elementary
organometallic
step
often
proposed
in
nickel-catalyzed
reactions.
Together,
these
results
hold
implications
for
number
Macromolecular Rapid Communications,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 13, 2025
Abstract
Aromatic
diimides
such
as
naphthalene
diimide
(NDI)
and
pyromellitic
(MDI)
are
important
building
blocks
for
organic
electrode
materials.
They
feature
a
two‐electron
redox
mechanism
that
allows
energy
storage.
Due
to
the
smaller
size
of
MDI
compared
NDI
its
theoretical
capacity
is
higher.
Studies
on
MDI‐based
small
molecule
linear
polymer
electrodes
indicate
unstable,
yet
origin
instability
remains
unclear.
Herein,
two
cross‐linked
networks
designed.
The
polymers,
termed
PNDI‐EG
PMDI‐EG,
synthesized
via
cationic
polymerization
vinyl
ethylene
glycol‐functionalized
monomers.
structures
preclude
extrinsic
degradation
pathways
(e.g.,
dissolution
in
electrolyte),
thereby
facilitate
investigation
intrinsic
mechanisms.
PMDI‐EG‐based
cathodes
less
stable,
performance
PMDI‐EG/Li
half
cells
markedly
inferior
PNDI‐EG/Li
cells.
Our
comprehensive
experimental
quantum‐chemical
reveals
PMDI‐EG
undergoes
irreversible
ring
opening
upon
prolonged
charge–discharge
cycles,
while
intact.
It
hypothesized
five‐membered
imide
renders
more
susceptible
side
reactions
with
nucleophiles
electrolyte,
causing
rapid
loss
during
first
cycles.
Journal of the American Chemical Society,
Год журнала:
2019,
Номер
142(1), С. 274 - 282
Опубликована: Ноя. 25, 2019
[Co(bapbpy)Cl]+
(bapbpy:
6,6′-bis(2-aminopyridyl)-2,2′-bipyridine)
is
a
polypyridyl
cobalt(II)
complex
bearing
both
redox-active
bipyridine
ligand
and
pendant
proton
relays.
This
compound
catalyzes
electro-assisted
H2
evolution
in
DMF
with
distinct
mechanisms
depending
on
the
strength
of
acid
used
as
source
(pKa
values
ranging
from
3.4
to
13.5
DMF)
applied
potential.
Electrochemical
studies
combining
cyclic
voltammetry
bulk
electrolysis
measurements
enabled
one
bring
out
four
catalytic
processes.
Where
applicable,
relevant
kinetic
information
were
obtained
using
either
foot-of-the-wave
analysis
(FOWA)
or
analytical
treatment
experiments.
Among
different
pathways
identified
this
study,
clear
relationship
between
catalyst
performances
stability
was
evidenced.
These
results
draw
attention
number
interesting
considerations
may
help
development
future
adequately
designed
catalysts.
Angewandte Chemie International Edition,
Год журнала:
2020,
Номер
59(33), С. 13962 - 13967
Опубликована: Май 12, 2020
We
report
a
method
for
the
electrochemical
deuteration
of
α,β-unsaturated
carbonyl
compounds
under
catalyst-
and
external-reductant-free
conditions,
with
rates
as
high
99
%
yields
up
to
91
in
2
h.
The
use
graphite
felt
both
cathode
anode
was
key
ensuring
chemoselectivity
deuterium
incorporation
neutral
conditions
without
need
an
external
reductant.
This
has
number
advantages
over
previously
reported
reactions
that
stoichiometric
metallic
reductants.
Mechanistic
experiments
showed
O2
evolution
at
not
only
eliminates
reductant
but
also
regulates
pH
reaction
mixture,
keeping
it
approximately
neutral.
Journal of the American Chemical Society,
Год журнала:
2021,
Номер
143(25), С. 9332 - 9337
Опубликована: Июнь 15, 2021
Here
we
report
the
use
of
pulse
radiolysis
and
spectroelectrochemistry
to
generate
low-valent
nickel
intermediates
relevant
synthetically
important
Ni-catalyzed
cross-coupling
reactions
interrogate
their
reactivities
toward
comproportionation
oxidative
addition
processes.
Pulse
provided
a
direct
means
singly
reduced
[(dtbbpy)NiBr],
enabling
identification
rapid
Ni(0)/Ni(II)
process
taking
place
under
electrolysis
conditions.
This
approach
also
permitted
measurement
Ni(I)
rates
with
electronically
differentiated
aryl
iodide
electrophiles
(kOA
=
1.3
×
104–2.4
105
M–1
s–1),
an
elementary
organometallic
step
often
proposed
in
nickel-catalyzed
reactions.
Together,
these
results
hold
implications
for
number
