Chemical Science,
Год журнала:
2022,
Номер
14(3), С. 491 - 498
Опубликована: Ноя. 28, 2022
Since
the
observation
of
chirality
at
nanoscale,
research
focused
towards
design
and
synthesis
optically
active
nanomaterials
has
been
a
brisk
pace.
In
this
regard,
carbon
based
zero
dimensional
have
attracted
vast
attention
due
to
their
rich
optical
properties,
abundance
raw
materials,
minimal
environmental
hazardousness,
good
solubility,
ease
surface
modification.
However,
efforts
chiral
nanodots
exhibiting
activity
both
in
ground
excited
states
are
rather
scarce.
Herein,
we
report
facile
synthetic
approach
for
preparation
three
sets
intrinsically
that
exhibit
intense
circularly
polarized
luminescence.
Synthesis
under
optimized
conditions
using
l-
d-isomers
precursors
led
formation
displayed
mirror
image
circular
dichroism
luminescence
signals
revealing
state
chirality.
The
experimental
results
supportive
reported
core-shell
model
comprising
an
achiral
core
is
enclosed
within
amorphous
shell
contributing
anisotropy
wavelength
could
be
tuned
by
varying
such
as
temperature
pH.
emissive
properties
nanoparticles
demonstrated
free-standing
polymeric
films
potential
used
light
emitting
agents
devices,
data
storage
security
tags.
Being
first
intrinsic
from
range
nanodots,
solution
solid
state,
envisage
work
will
open
new
avenues
investigation
stated
nanoscale.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(48)
Опубликована: Авг. 20, 2024
Abstract
Carbon
dots
(CDs)
have
rapidly
emerged
as
a
new
family
of
carbon‐based
nanomaterials
since
their
initial
discovery
two
decades
ago.
Numerous
appealing
properties,
such
precursor
and
synthesis
process
flexibility,
tunable
photoluminescence,
good
biocompatibility,
enabled
widespread
applications
in
sensing,
catalysis,
energy,
biomedical
fields.
As
the
field
expands,
notable
efforts
recently
focused
on
mechanistically
elucidating
structural
formation
optical
behavior
CDs.
However,
absence
“clean”
CDs
presents
major
obstacle
to
achieving
solid
understanding
these
aspects.
Often,
claimed
are,
fact,
mixture
small
molecules,
oligomers,
nano‐sized
aggregates,
or
even
microparticles.
Such
coexistence
impurities
markedly
impacts
physicochemical
properties
resulting
CD‐based
mixtures,
hampering
resolution
key
mechanistic
questions.
Here,
we
aim
address
this
fundamental
shortcoming
field,
going
beyond
customary
focus
existing
reviews
that
predominantly
cover
synthesis,
performance,
application
prospects.
We
begin
with
an
overview
CD
then
thoroughly
examine
purification
methods,
including
filtration,
dialysis,
electrophoresis,
chromatography.
The
insights
provided
here
will
guide
researchers
towards
obtaining
high‐quality
CDs,
employing
proper
combinations
available
tools,
ultimately
paving
way
for
more
demanding
applications.
The
chemical
structure
and
photoredox
properties
of
carbon
dots
(CDs)
are
not
yet
fully
understood.
However,
it
has
been
reported
that,
by
carefully
choosing
the
starting
materials
tuning
their
synthesis
conditions,
is
possible
to
obtain
CDs
with
different
structures
therefore
photocatalytic
performance.
For
this
work,
a
family
was
synthesized
in
Milli-Q
water
via
microwave-assisted
protocol,
using
citric
acid
urea
as
precursors.
syntheses
were
carried
out
at
times
temperatures
assess
impact
synthetic
parameters
on
final
materials.
After
extensive
accurate
purification,
abilities
selected
subset
tested
performing
photocatalyzed
atom
transfer
radical
addition
reaction.
Among
CDs,
best
ones
found
be
those
highest
temperature,
which
most
graphitic.
A
number
characterization
techniques
then
used
evaluate
degree
graphitization
elucidate
origin
Abstract
Carbon
dots
(CDs)
or
carbonized
polymer
(CPDs)
are
an
emerging
class
of
optical
materials
that
have
exceptional
applications
in
optoelectronic
devices,
catalysis,
detection,
and
bioimaging.
Although
cell
studies
CPDs
produced
impressive
results,
vivo
imaging
requires
available
to
fluoresce
the
near‐infrared‐II
(NIR‐II)
window
(1000−1700
nm).
Here,
a
two‐step
bottom‐up
strategy
is
developed
synthesize
NIR‐CPDs
provide
bright
emissions
both
NIR‐I
NIR‐II
transparent
windows.
The
designed
includes
hydrothermal
reaction
form
stable
carbon
core
with
aldehyde
groups,
followed
by
Knoevenagel
tether
molecular
emission
centers.
This
procedure
labor‐saving,
cost‐efficient,
produces
high
yield.
enable
high‐performance
angiography
real‐time
disease
degree
colitis
noninvasively.
technology
may
therefore
next‐generation
synthesis
for
rational
engineering
can
accurately
tune
absorption/emission
properties
NIR‐emissive
CPDs.
Angewandte Chemie International Edition,
Год журнала:
2022,
Номер
61(26)
Опубликована: Апрель 13, 2022
We
report
the
synthesis,
purification
and
characterization
of
chiral
carbon
nanodots
starting
from
atropoisomeric
precursors.
The
obtained
are
soluble
in
organic
solvents
have
good
thermal
stability,
which
desirable
features
for
technological
applications.
synthetic
protocol
is
robust,
as
it
supports
a
number
variations
terms
molecular
doping
agents.
Remarkably,
combination
axially
precursors
1,4-benzoquinone
agent
results
green-emissive
dots
displaying
circularly
polarized
luminescence.
Dissymmetry
factors
|3.5|×10
ACS Nano,
Год журнала:
2023,
Номер
17(22), С. 22788 - 22799
Опубликована: Ноя. 16, 2023
A
major
challenge
in
the
"bottom-up"
solvothermal
synthesis
of
carbon
dots
(CDs)
is
removal
small-molecule
byproducts,
noncarbonized
polyamides,
or
other
impurities
that
confound
optical
properties.
In
previously
reported
benzene
diamine-based
CDs,
observed
fluorescence
signal
already
has
been
shown
to
arise
from
free
small
molecules,
not
nanosized
carbonized
dots.
Here
we
have
unambiguously
identified
species
CDs
starting
with
several
isomers
diamine
by
directly
matching
their
NMR,
mass
spectrometry,
and
data
commercially
available
organic
molecules.
By
combining
dialysis
chromatography,
sufficiently
purified
CD
reaction
mixtures
measure
size
TEM
STM,
elemental
composition,
absorption
emission,
single-particle
blinking
dynamics.
The
results
can
be
rationalized
electronic
structure
calculations
on
model
CDs.
Our
conclusively
show
do
emit
red
fluorescence,
so
quest
for
full-spectrum
a
single
precursor
molecule
remains
open.
Angewandte Chemie International Edition,
Год журнала:
2024,
Номер
63(22)
Опубликована: Март 22, 2024
Nanozymes
possess
multi-enzyme
activities
over
the
natural
enzymes,
which
produce
multi-pathway
synergistic
effects
for
varies
of
biomedical
applications.
Unfortunately,
their
are
in
fighting,
significantly
reducing
effects.
Dynamic
regulation
is
bottleneck
intelligent
therapies.
Herein,
we
construct
a
novel
oxygen-nitrogen
functionalized
carbon
quantum
dots
(O/N-CQDs)
with
peroxidase-like
(Reactive
oxygen
species
(ROS)
producer)
activity.
Interestingly,
activity
can
be
reversibly
converted
to
catalase-like
(ROS
scavenger)
under
visible
light
irradiation.
It
found
that
both
peroxidase/catalase-like
O/N-CQDs
precisely
manipulated
by
intensity.
The
mechanism
switchable
enzyme
attributed
polarization
quinoid
nitrogen
polyaniline
(PANI)
precursor
retained
on
light,
consumes
ROS
O
