Hyperconjugation Engineering of π-Extended Azaphosphinines for Designing Tunable Thermally Activated Delayed Fluorescence Emitters
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Jan. 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
Language: Английский
Mono- and Bis-Phosphine Promoted Incorporation of Boron, Nitrogen, and Phosphorus into Heterocycles via Staudinger Reactions of Borafluorene Azides
Inorganic Chemistry,
Journal Year:
2024,
Volume and Issue:
63(25), P. 11604 - 11615
Published: June 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.
Language: Английский