Angewandte Chemie,
Год журнала:
2024,
Номер
136(27)
Опубликована: Апрель 22, 2024
Abstract
The
first
synthesis
of
well‐defined
poly(methylene‐
co
‐1,1‐diphenylpropenenylene)
(C1‐
‐C1’),
equivalent
to
poly(ethylene‐
‐diphenylbutadiene)
copolymers
was
accomplished
by
C1
copolymerization
novel
diphenylpropenyl
triphenyl
arsonium
ylides
(Ph
2
AY)
and
dimethylsulfoxonium
methylide
(Me
SY)
using
B‐thexylborepane
as
initiator.
All
polymerization
conditions,
including
feed
ratio,
temperature,
reaction
time,
were
optimized.
A
series
photoluminescent
‐diphenylbutadiene)s
synthesized
at
different
ratios,
opening
a
new
synthetic
horizon
for
‐disubstitutedbutadiene)
copolymers.
Notably,
segment,
arising
from
double
bond
rearrangement,
confirmed
NMR,
resulting
in
an
unprecedented
two‐monomer
three‐structure
random
terpolymer.
An
unexpected
red‐shift
phenomenon
the
fluorescence
spectra
observed
with
increasing
ratio
Ph
AY
copolymer.
This
shift
is
attributed
aggregation
diphenylbutadiene
similar
through‐space
conjugation
(TSC),
likely
induced
decrease
crystallinity
Furthermore,
another
disubstituted
allylic
ylides,
(
E
)‐2‐phenylbutenyl
ylide
(MePhAY)
also
investigated.
These
additional
compounds
expand
knowledge
potential
applications
such
techniques
advanced
materials.
Free
radical
photopolymerization,
a
pivotal
technology
in
materials
processing,
is
extensively
utilized
for
radiation
curing
and
micro/nanoscale
patterning.
Yet,
it
commonly
suffers
from
oxygen
inhibition,
which
diminishes
curability
submicron
films
degrades
performance.
To
address
this
issue,
we
develop
novel
class
of
(Z)-2-((Z)-2-(hydroxyimino)thiophen-3(2H)-ylidene)-2-(o-tolyl)acetonitrile-derived
oxime
esters
(OXEs)
formulate
hybrid
photoinitiators
by
blending
these
OXEs
with
tetrabutylammonium
butyltriphenylborates.
Acting
as
electron
acceptors
donors,
respectively,
OXEs,
along
butyltriphenylborates,
enable
photoinduced
transfer,
leading
to
the
formation
triphenylborane
n-butyl
radicals.
The
resultant
reacts
or
peroxyl
radicals,
generating
radicals
initiating
activity
preserving
antioxygen
inhibition
capability
throughout
photopolymerization
process.
Under
LED@405
nm
light
curing,
significantly
outperform
commercial
diphenyl(2,4,6-trimethylbenzoyl)phosphine
oxide,
achieving
up
85%
retention
cured
acrylate
resins
air
compared
only
8%
initiator.
This
OXE/triarylalkylborate
system
presents
an
exceptional
photoinitiation
ability,
showcasing
potential
widespread
use
photopolymerization.
Biomimetic
catalysis
is
extensively
used
in
chemical
synthesis
targeting
to
achieve
satisfactory
reactivities.
However,
artificial
catalysts
possessing
outstanding
sequence
controllability
over
macromolecular
structures
that
could
be
precisely
achieved
nature
remain
scarce,
especially
the
preparation
of
complex
macromolecules
featuring
kinetically
trapped
structures.
Herein,
we
report
a
dual
biomimetic
catalyst
design
for
precise
regulation
controlled
CO2/epoxide
copolymerization.
The
as-synthesized
dissymmetric
organoboron
possess
microenvironments,
which
differentiate
transfer
rates
polymer
alkoxy
anions
between
two
boron
centers,
thus
enabling
regulation.
Consequently,
high
−ABB–/–AB–
ratio
92%
was
achieved,
up
3.3
times
analogous
symmetric
(Nat.
Synth.
2022,
1,
892–901).
Detailed
mechanistic
studies
reveal
kinetic
modulations
are
responsible
This
tactic
should
inspire
effective
designs
transformations.
Abstract
Carbon
dioxide
based
degradable
polycarbonate
can
be
obtained
through
the
copolymerization
reaction
of
carbon
with
epoxide
in
presence
a
catalyst.
This
polymer
has
attracted
much
attention
recent
years
owing
to
its
environmentally
friendly
and
sustainable
characteristics,
excellent
material
properties.
Due
unique
properties,
CO2-based
wide
range
applications
many
fields
such
as
electronic
electrical
parts,
automotive
medical
devices,
aerospace
equipment,
power
radiation
protection
products.
Therefore,
numerous
catalytic
systems
have
been
explored
for
CO2/epoxide
process,
which
zinc
catalyst
longest
history
greatest
variety.
In
this
short
review,
significant
advances
catalysts
transformation
CO2
are
demonstrated,
covering
both
heterogeneous
homogeneous
catalysts.
Moreover,
benefits
drawbacks
system
described,
outlook
large-scale
industrial
applicati
ons
future
is
also
represented.
1
Introduction
2
Heterogeneous
Zinc
Catalysts
3
Homogeneous
4
Overview
5
Conclusion
Catalysts
combining
commercial
borane
Lewis
acids
and
potassium
acetate
complexes
achieve
the
selective
ring-opening
copolymerization
(ROCOP)
of
oxetanes
with
diverse
sulfur-containing
monomers.
ACS Catalysis,
Год журнала:
2025,
Номер
unknown, С. 6760 - 6771
Опубликована: Апрель 11, 2025
Understanding
catalysts,
and
improving
their
future
performances,
requires
quantification
of
kinetic
thermodynamic
parameters,
including
measurement
rate
constants
(k
obs),
transition
state
enthalpy
barriers
(ΔH
‡)
polymerization
entropy
p,
ΔS
p).
This
work
presents
miniaturized
automated
methods,
conducted
using
common
differential
scanning
calorimetry
(DSC)
instruments
<10
mg
sample
(polymer,
solvent,
initiator
catalyst),
to
reliably,
accurately,
rapidly
measure
all
these
key
catalyst
performance
parameters.
The
methods
are
tested
known
highly
successful
catalyst/alcohol
systems
(tin(II)bis(2-ethyl
hexanoate),
Sn(Oct)2,
benzyl
alcohol,
BnOH)
for
cyclic
ester
or
carbonate
ring-opening
polymerizations,
a
catalyst/ionic
cocatalyst
((salcy)CrCl
Bu4NCl)
system
epoxide/cyclic
anhydride
copolymerizations-two
growth
fields
in
catalysis.
DSC-measured
parameters
identical
less
error
prone
than
those
determined
conventional
lab-scale
experiments
by
aliquot
removal.
DSC
kinetics
measured
significantly
smaller
amounts
materials,
600x
sample,
while
being
more
time-efficient.
successfully
demonstrated
both
neat
monomer
(bulk)
solution
phase
reactions,
which
testing
application
yield
reproducible
accurate
turn
over
frequency
values,
constants,
activation
rate-determining
transition-state
enthalpies.
In
addition
quantifying
second
methodology
is
exemplified
two
carbonates,
enabling
change.
paper
outlines
recommendations
that
should
enable
researchers
apply
the
method
