Hyperconjugation Engineering of π-Extended Azaphosphinines for Designing Tunable Thermally Activated Delayed Fluorescence Emitters
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 20, 2025
Implanting
heteroatoms
into
organic
π-conjugated
molecules
(OCMS)
offered
a
great
opportunity
to
fine-tune
the
chemical
structures
and
optoelectronic
properties.
This
work
describes
new
family
of
1,4-azaphosphinines
with
extended
σ–π
hyperconjugations.
The
photophysical
studies
revealed
that
azaphosphinines
exhibited
narrow-band
thermally
activated
delayed
fluorescence
(TADF)
(
full
width
at
half-maximum:
26–40
nm).
According
orbital
localization
analysis
natural
bond
analysis,
effective
σ*−π*
hyperconjugation
is
believed
induce
multiple-resonance
(MR)
TADF,
which
distinct
from
p−π
conjugation-induced
MR-TADF
in
BN
systems.
Although
having
large
ΔES1–T1s
(>3.0
ev),
study
suggested
σ*−π
endowed
system
structural
vibration
favorable
for
spin-vibronic-assisted
RISC.
Having
tunable
p-centers
(lp,
O,
S,
Se,
Me+),
showed
fine-tuned
TADF.
Generally,
strong
hyperconjugations
small
ΔES1–T1s,
efficient
RISCs,
high
PLQYs.
Leveraging
on
hyperconjugations,
TADF
emission
spanned
UV-blue
green.
Particularly,
photoluminescence
quantum
yields
(74%
toluene
92%
10%
doped
PMMA).
As
proof
concept,
two
PO
center
were
applied
as
light-emitting
materials
lighting-emitting
diodes.
devices
UV-
deep-blue
EQE
10.3%.
current
us
strategy,
namely,
hyperconjugation-induced
MR-TADF,
designing
OCMs
Язык: Английский
Copper-Catalyzed Formal Aldehydic C–H Borylation Enabled by an sp2–sp3 Diboron Reagent
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 20, 2025
We
have
developed
a
copper-catalyzed
formal
aldehydic
C-H
borylation
using
neutral
sp2-sp3
diboron
reagent,
LBH2-Bpin
(where
L
is
σ-donor),
leading
to
the
one-pot
synthesis
of
diverse
acylboranes.
Notably,
BH
moieties
in
acylborane
can
be
further
used
construct
boracycles.
This
protocol
enables
straightforward
functional
group
(FG)
replacement
commercial
medicines
with
an
acylboron
motif.
Detailed
mechanistic
studies
and
DFT
calculations
reveal
synergistic
hydride
transfer
pathway,
which
promoted
by
electron-rich
nature
LBH2
fragment.
investigation
highlights
potential
new
reagent
accessing
reaction
modes
that
were
previously
unachievable.
Язык: Английский
Diboron-Incorporated Indenofluorene: Isolation of Crystalline Neutral and Reduced States of 6,12-Diboraindeno[1,2-b]fluorene
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 21, 2025
The
synthesis
and
redox
transformations
of
6,12-diboraindeno[1,2-b]fluorene
(DBIF)─a
pentacyclic
π-system
with
diboron
incorporation─are
reported.
In
notable
contrast
to
the
all-hydrocarbon
indenofluorenes,
a
ligand
coordination
reduction
strategy
allows
tuning
electronic
structure
across
four
states.
Accordingly,
we
introduce
an
18π
e-
neutral
DBIF,
20π
diradical,
21π
radical
anion,
22π
dianion,
all
which
have
been
isolated
structurally
authenticated.
diradicals
exhibit
diradical
character
up
77%
possess
open-shell
singlet
ground
states
thermally
accessible
triplet
Язык: Английский
Mono- and Bis-Phosphine Promoted Incorporation of Boron, Nitrogen, and Phosphorus into Heterocycles via Staudinger Reactions of Borafluorene Azides
Inorganic Chemistry,
Год журнала:
2024,
Номер
63(25), С. 11604 - 11615
Опубликована: Июнь 12, 2024
We
report
the
synthesis
and
characterization
of
a
series
BNP-incorporated
borafluorenate
heterocycles
formed
via
thermolysis
reactions
pyridylphosphine
bis(phosphine)-coordinated
borafluorene
azides.
The
use
diphenyl-2-pyridylphosphine
(PyPh2P),
trans-1,2-bis(diphenylphosphino)ethylene
(Ph2P(H)C═C(H)PPh2),
bis(diphenylphosphino)methane
(Ph2PC(H2)PPh2)
as
stabilizing
ligands
resulted
in
Staudinger
to
form
complex
with
four-
(BN2P,
BNPC,
P2N2)
five-membered
(BNP2C
BN2PC)
rings,
which
were
successfully
isolated
fully
characterized
by
multinuclear
NMR
X-ray
crystallography.
However,
when
bis(diphenylphosphino)benzene
(Ph2P-Ph-PPh2)
was
used
ligand
reaction
9-bromo-9-borafluorene
(BF-Br),
due
close
proximity
donor
P
atoms,
diphosphine-stabilized
borafluoronium
ion
an
unusual
dibromide
anion
formed.
Reaction
trimethylsilyl
azide
left
cation
intact,
substituted
diazide.
Density
functional
theory
calculations
provide
mechanistic
insight
into
formation
these
new
boracyclic
compounds.
This
work
highlights
method
phosphine
may
be
promote
dimerization,
cyclization,
ring
contraction
produce
boracycles
reactions.
Язык: Английский