Isomeric Azulene-Based Carbon-Centered Radicals Derived from N-Heterocyclic Carbenes
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Фев. 12, 2025
Azulene
(isomer
with
naphthalene),
a
representative
nonalternant
hydrocarbon,
has
attracted
significant
attention
as
building
block
for
π-extended
molecules
owing
to
its
distinctive
electronic
structure
and
physicochemical
properties
that
differ
from
those
of
conventional
alternant
hydrocarbons.
Nevertheless,
the
development
stable
carbon-centered
radicals
utilizing
an
azulene
moiety
remains
relatively
scarce.
Herein,
we
report
structures
optical
azulene-based
radical
isomers,
1
2,
which
were
designed
synthesized
by
attaching
N-heterocyclic
carbenes
(NHCs)
6-position
seven-membered
ring
or
2-position
five-membered
azulene,
respectively.
Density
functional
theory
calculations
reveal
spin
density
in
is
primarily
localized
on
indicating
it
cyclopentadienyl
radicals,
whereas
predominantly
distributed
serving
example
cycloheptatrienyl
radicals.
Furthermore,
although
both
2
exhibit
anti-Kasha
emission,
emission
wavelength
(λem
∼
495
nm)
significantly
red-shifted
compared
396
nm).
Язык: Английский
Redox- and Charge-State Dependent Trends in 5, 6, and 7-Membered Boron Heterocycles: A Neutral Ligand Coordination Chemistry Approach to Boracyclic Cations, Anions, and Radicals
Accounts of Chemical Research,
Год журнала:
2024,
Номер
57(10), С. 1510 - 1522
Опубликована: Май 6, 2024
ConspectusBoron
heterocycles
represent
an
important
subset
of
heteroatom-incorporated
rings,
attracting
attention
from
organic,
inorganic,
and
materials
chemists.
The
empty
pz
orbital
at
the
boron
center
makes
them
stand
out
as
quintessential
Lewis
acidic
molecules,
also
serving
a
means
to
modulate
electronic
structure
photophysical
properties
in
facile
manner.
As
boracycles
are
ripe
for
extensive
functionalization,
they
used
catalysis,
chemical
biology,
science,
continue
be
explored
synthons
conjugated
reagents.
Neutral
boron(III)-incorporated
polycyclic
molecules
some
most
studied
types
boracycles,
understanding
their
redox
transformations
is
applications
relying
on
electron
transfer
charge
transport.
While
relevant
species
can
often
electrochemically
observed,
it
remains
challenging
isolate
characterize
where
and/or
skeleton
have
been
chemically
reduced.We
describe
our
recent
work
isolating
5-,
6-,
7-membered
boracyclic
radicals,
anions,
cations,
focusing
stabilization
strategies,
ligand-mediated
bonding
situations,
reactivity.
We
present
versatile
neutral
ligand
coordination
chemistry
approach
that
permits
transformation
potent
electrophiles
powerful
nucleophilic
facilitate
diverse
bond
activation
chemistry.
Although
there
wide
range
suitable
stabilizing
ligands,
we
employed
both
diamino-N-heterocyclic
carbenes
(NHCs)
cyclic(alkyl)(amino)
(CAACs),
which
led
with
tunable
structures
aromaticity
trends.
highlight
successful
isolation
borafluorene
radicals
demonstrate
reversible
behavior,
undergoing
oxidation
cation
or
reduction
anion.
anion
synthon
has
prepare
boryl
main-group
transition-metal
bonds,
luminescent
oxabora-spirocycles,
borafluorenate-crown
ethers,
CO-releasing
via
carbon
dioxide
activation.
expanded
6-membered
characterized
bis(NHC-supported
9-boraphenanthrene)s
corresponding
bis(CAAC-stabilized
9-boraphenanthrene)
biradical.
detail
interconvertible
multiredox
states
boraphenalene,
boraphenalenyl
radical,
anion,
mimic
charge-states
all-hydrocarbon
analogue.
Reactivity
studies
displayed
unusual
reactivity
multiple
sites
periphery
tricyclic
scaffold.
Reduced
borepins,
containing
heterocycles,
isolated.
stepwise
one-pot
synthesis
combining
halo-borepin
precursor,
CAAC,
KC8
afford
monomeric
borepin
anions.
π-system
was
extended
contain
two
rings
fused
pentacyclic
scaffold,
permitted
diborepin
biradicals
dibora-quinone
core.Our
goal
provide
guide
explaining
current
structure–function
trends
strategies
redox-active
boron-incorporated
initiate
rational
design
use
these
compounds
across
vast
space.
Язык: Английский
Reactivity of a Hexaaryldiboron(6) Dianion as Boryl Radical Anions
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(25), С. 17348 - 17354
Опубликована: Июнь 12, 2024
Our
study
unveils
a
novel
approach
to
accessing
boryl
radicals
through
the
spontaneous
homolytic
cleavage
of
B–B
bonds.
We
synthesized
hexaaryl-substituted
diboron(6)
dianion,
1,
via
reductive
coupling
9-borafluorene.
Intriguingly,
compound
1
exhibits
ability
undergo
bond
cleavage,
leading
formation
radical
anions,
as
confirmed
by
EPR
studies,
in
presence
2.2.2-cryptand
at
room
temperature.
Moreover,
it
directly
reacts
with
diphenylacetylene,
producing
an
unprecedented
1,6-diborylated
allene
species,
where
phenyl
ring
is
dearomatized.
Density
functional
theory
computational
studies
suggest
that
favored
reaction
path,
and
anion
crucial
for
dearomatization.
Additionally,
achieves
dearomative
diborylation
anthracene
activation
elemental
sulfur/selenium
under
mild
conditions.
The
borylation
products
have
been
successfully
characterized
NMR
spectra,
HRMS,
X-ray
single-crystal
diffraction.
Язык: Английский
Carborane–arene fused boracyclic analogues of polycyclic aromatic hydrocarbons accessed by intramolecular borylation
Chemical Science,
Год журнала:
2024,
Номер
15(20), С. 7568 - 7575
Опубликована: Янв. 1, 2024
Carborane
fused
boron
doped
polycyclic
aromatic
hydrocarbons
were
accessed
by
dehydrobrominative
and
dehydrogenative
borylation.
Язык: Английский
Dicationic Boron Derivatives of Schlenk’s and Thiele’s Hydrocarbon
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 19, 2025
In
recent
years,
neutral
NHC-stabilized
boryl
radicals
have
been
investigated
as
reactive
species
in
various
organic
transformations.
However,
cationic
boron
significantly
less
explored.
addition,
boron-centered
open-shell
with
S
>
1/2
emerged
attractive
synthetic
targets.
this
study,
we
provide
a
route
to
an
radical
cation
salt
of
the
weakly
coordinating
[Al(ORF)4]-
(RF
=
C(CF3)3)
anion.
The
procedure
was
extended
dicationic
diboron
derivatives
Schlenk's
and
Thiele's
hydrocarbons
meta-
para-phenylene
coupling
units
between
spin
centers.
While
most
known
isolable
biradicals
singlet
ground-state
thermally
accessible
triplet
state,
version
hydrocarbon
occupies
spin-state,
shown
by
combined
electron
paramagnetic
resonance
spectroscopy
density
functional
theory
studies.
Furthermore,
initial
reactivity
studies
dications
elemental
sulfur
diphenyldiselenide
are
presented.
Язык: Английский
Phenalenyl Chemistry Revisited: Stable and Bioactive Multisubstituted Phenalenyl Radicals Synthesized via a Protection–Oxidation–Protection Strategy
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 15, 2025
Phenalenyl
chemistry
has
flourished
for
decades
but
currently
faces
bottlenecks
related
to
synthetic
challenges
and
stability
issues.
In
this
study,
we
introduced
an
iterative
protection-oxidation-protection
(POP)
strategy
synthesize
stabilized
phenalenyl
radicals
(PRs)
with
multiple
substitutions
at
the
α-positions.
The
applicability
of
POP
was
verified
using
triisopropylsilylthyl
phenyl
substituents
generate
trisubstituted
PR1
hexasubstituted
PR2.
particular,
both
oxidation
dimerization
were
observed
during
synthesis
involving
substituents.
Both
PR2
bench-stable,
half-lives
in
solution
up
46
d
thermal
decomposition
temperatures
300
°C.
X-ray
crystallographic
analysis
revealed
that
existed
as
a
distinct
12-center-2-electron
π-dimer,
whereas
monomer.
properties
associated
monomer-dimer
equilibrium
solid
state
systematically
investigated
via
variable-temperature
spectroscopy,
results
small
singlet-triplet
energy
gap
concentration-dependent
absorption
electrochemical
behaviors.
Remarkably,
formed
biocompatible
nanoparticles,
latter
capable
depleting
reactive
oxygen
species
liver
cells.
This
study
thus
demonstrated
construction
stable,
functionalized
PR
derivatives
practical
applications
spin
functional
materials.
Язык: Английский
Oxa-phenalene [b]-fused BODIPY Dyes: Synthesis, Structures, and Photophysical Properties
Tetrahedron,
Год журнала:
2025,
Номер
unknown, С. 134728 - 134728
Опубликована: Май 1, 2025
Язык: Английский
Crystalline Radical Anion of a Diboratriazole and Its Conversion to a Neutral Radical Driven by a Carbene
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
146(30), С. 20945 - 20950
Опубликована: Июль 21, 2024
One-electron
reduction
of
diboratriazole
Язык: Английский
Pentacyclic fused diborepinium ions with carbene- and carbone-mediated deep-blue to red emission
Chemical Science,
Год журнала:
2024,
Номер
15(35), С. 14358 - 14370
Опубликована: Янв. 1, 2024
Designing
molecules
that
can
undergo
late-stage
modifications
resulting
in
specific
optical
properties
is
useful
for
developing
structure-function
trends
materials,
which
ultimately
advance
optoelectronic
applications.
Herein,
we
report
a
series
of
fused
diborepinium
ions
stabilized
by
carbene
and
carbone
ligands
(diamino-N-heterocyclic
carbenes,
cyclic(alkyl)(amino)
carbodicarbenes,
carbodiphosphoranes),
including
detailed
bonding
analysis.
These
are
the
first
structurally
confirmed
examples
diborepin
dications
detail
how
distortions
core
pentacyclic
system
impact
aromaticity,
stability,
their
light-emitting
properties.
Using
same
scaffold,
coordinating
were
used
to
dramatically
shift
emission
profile,
exhibit
colors
ranging
from
blue
red
(358-643
nm).
Notably,
these
access
expanded
regions
visible
spectrum
compared
known
borepins,
with
quantum
yields
up
60%.
Carbones
determined
be
superior
stabilizing
ligands,
improved
stability
solution
solid
states.
Density
functional
theory
was
provide
insight
into
as
well
transitions
result
observed
photophysical
Язык: Английский
Recent Advances in NIR‐Switchable Multi‐Redox Systems Based on Organic Molecules
Chemistry - A European Journal,
Год журнала:
2024,
Номер
unknown
Опубликована: Ноя. 6, 2024
Abstract
Electrochromic
systems
capable
of
switching
absorption
in
the
near‐infrared
(NIR)
region
(750–2500
nm)
are
attractive
from
viewpoint
applications
for
material
and
life
science,
thus
several
examples
have
been
reported
to
date.
In
general,
development
organic‐based
is
needed
reduce
environmental
impact
improve
biocompatibility.
Although
extending
switchable
spectral
range
crucial
application
organic
electrochromic
molecules,
NIR
based
on
redox
interconversion
still
a
challenging
issue
regarding
reversibility
durability
during
interconversion.
To
overcome
this
potential
instability,
introduction
heteroatoms
into
molecular
backbone
and/or
π‐extension
could
be
useful
strategies
terms
effective
delocalization
charge
spin
corresponding
states.
review,
we
focus
redox‐active
well‐defined
small
molecules
that
enable
ON/OFF
precise
control
states,
present
recent
studies
their
intrinsic
electrochemical
spectroscopic
properties
structural
characterization
charged
Язык: Английский