Journal of Chemical Theory and Computation,
Год журнала:
2024,
Номер
20(21), С. 9488 - 9499
Опубликована: Окт. 29, 2024
Radical
pairs
(electron-hole
pairs,
polaron
pairs)
are
transient
reaction
intermediates
that
found
and
exploited
in
all
areas
of
science,
from
the
hard
realm
physics
form
organic
semiconductors,
spintronics,
quantum
computing,
solar
cells
to
soft
domain
chemistry
biology
under
guise
chemical
reactions
solution,
biomimetic
systems,
biology.
Quantitative
analysis
radical
pair
phenomena
has
historically
been
successful
by
a
few
select
groups.
With
this
mind,
we
present
an
intuitive
open-source
framework
Python
programming
language
provides
classical,
semiclassical,
simulation
methodologies.
A
kinetic
rate
equation
solver,
Monte
Carlo-based
spin
dephasing
estimations,
molecule
database
functionalities
implemented.
We
introduce
Science,
Год журнала:
2023,
Номер
382(6667), С. 197 - 201
Опубликована: Окт. 12, 2023
The
role
of
chirality
in
determining
the
spin
dynamics
photoinduced
electron
transfer
donor-acceptor
molecules
remains
an
open
question.
Although
chirality-induced
selectivity
(CISS)
has
been
demonstrated
bound
to
substrates,
experimental
information
about
whether
this
process
influences
themselves
is
lacking.
Here
we
used
time-resolved
paramagnetic
resonance
spectroscopy
show
that
CISS
strongly
isolated
covalent
donor-chiral
bridge-acceptor
(D-Bχ-A)
which
selective
photoexcitation
D
followed
by
two
rapid,
sequential
electron-transfer
events
yield
D•+-Bχ-A•-.
Exploiting
phenomenon
affords
possibility
using
chiral
molecular
building
blocks
control
states
quantum
applications.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(48)
Опубликована: Окт. 6, 2023
Abstract
Time‐resolved
EPR
(TR‐EPR)
demonstrates
the
formation
of
well‐defined
spin
triplet
excitons
in
carbon
nitride.
This
permits
to
experimentally
probe
extent
wavefunction
which
delocalizes
over
several
tri‐
s
‐triazine
units.
Analysis
temperature
dependence
TR‐EPR
signal
reveals
mobility
excitons.
By
employing
monochromatic
light
excitation
range
430–600
nm,
energy
is
estimated
be
≈0.2
eV
above
conduction
band
edge,
proving
that
exciton
lies
corresponding
singlet.
Comparison
between
amorphous
and
graphitic
forms
establishes
singlet‐triplet
inversion
as
a
general
feature
nitride
materials.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
145(38), С. 20883 - 20896
Опубликована: Сен. 14, 2023
Covalent
dimers,
particularly
pentacenes,
are
the
dominant
platform
for
developing
a
mechanistic
understanding
of
intramolecular
singlet
fission
(iSF).
Numerous
studies
have
demonstrated
that
photoexcited
state
in
these
structures
can
rapidly
and
efficiently
undergo
exciton
multiplication
to
form
correlated
pair
triplets
within
single
molecule,
with
potential
applications
from
photovoltaics
quantum
information
science.
One
most
significant
barriers
limiting
such
dimers
is
fast
recombination
triplet
pair,
which
prevents
spatial
separation
formation
long-lived
states.
There
an
ever-growing
need
develop
general
synthetic
strategies
control
evolution
following
iSF
enhance
their
lifetime.
Here,
we
rationally
tune
dihedral
angle
interchromophore
between
pairs
pentacenes
systematic
series
bridging
units
facilitate
separation.
Through
combination
transient
optical
spin-resonance
techniques,
demonstrate
torsion
linker
provides
simple
handle
fine
balance
through-bond
through-space
couplings
steer
iSF.
We
show
full
pathway
femtosecond
microsecond
timescales
tuned
through
static
coupling
set
by
molecular
design
structural
fluctuations
be
biased
steric
control.
Our
approach
highlights
straightforward
principle
generate
paramagnetic
spin
states
higher
yields.
Chemical Science,
Год журнала:
2023,
Номер
14(39), С. 10727 - 10735
Опубликована: Янв. 1, 2023
Owing
to
their
potential
applications
in
the
field
of
quantum
information
science,
photogenerated
organic
triplet-radical
conjugates
have
attracted
an
increasing
amount
attention
recently.
Typically,
these
compounds
are
composed
a
chromophore
appended
stable
radical.
After
initialisation
system
by
photoexcitation,
highly
spin-polarised
quartet
state
may
be
generated,
which
serves
as
molecular
spin
qubit
candidate.
Here,
we
investigate
three
perylene
diimide
(PDI)-based
chromophore-radical
systems
with
different
phenylene
linkers
and
radical
counterparts
both
optical
spectroscopy
transient
electron
paramagnetic
resonance
(EPR)
techniques.
Femtosecond
absorption
measurements
demonstrate
triplet
formation
on
picosecond
time
scale
for
PDI-trityl
dyads,
while
excited
deactivation
is
found
slowed
down
considerably
PDI-nitroxide
analogue.
The
subsequent
investigation
coherent
properties
EPR
confirms
triplet-doublet
mixing
all
investigated
dyads
suitability
two
studied
candidates.
In
particular,
show
that
using
tetrathiaryl
trityl
counterpart,
intense
polarisation
observed
even
at
room
temperature
coherence
times
3.0
μs
can
achieved
80
K,
represents
considerable
improvement
compared
previously
systems.
Journal of the American Chemical Society,
Год журнала:
2023,
Номер
146(1), С. 1089 - 1099
Опубликована: Дек. 29, 2023
The
photogeneration
of
multiple
unpaired
electron
spins
within
molecules
is
a
promising
route
to
applications
in
quantum
information
science
because
they
can
be
initialized
into
well-defined,
multilevel
states
(S
>
1/2)
and
reproducibly
fabricated
by
chemical
synthesis.
However,
coherent
manipulation
these
spin
difficult
realize
typical
molecular
systems
due
the
lack
selective
addressability
short
coherence
times
transitions.
Here,
challenges
are
addressed
using
donor–acceptor
single
cocrystals
composed
pyrene
naphthalene
dianhydride
host
spatially
oriented
triplet
excitons,
which
exhibit
photogenerated
qutrit
properties.
Time-resolved
paramagnetic
resonance
(TREPR)
spectroscopy
demonstrates
that
orienting
excitons
crystal
platform
imparts
narrow,
well-resolved,
tunable
resonances
EPR
spectrum,
allowing
sublevel
Pulse-EPR
reveals
at
temperatures
above
30
K,
decoherence
driven
exciton
diffusion.
limited
electronic
dipolar
coupling
below
where
T2
varies
nonlinearly
with
optical
excitation
density
annihilation.
Overall,
an
optimized
time
=
7.1
μs
20
K
achieved.
These
results
provide
important
insights
designing
solid-state
excitonic
materials
improved
The Journal of Physical Chemistry C,
Год журнала:
2024,
Номер
128(4), С. 1603 - 1611
Опубликована: Янв. 17, 2024
Perylenediimide
(PDI)
and
its
derivatives
have
garnered
significant
attention
as
promising
n-type
semiconductors
to
replace
fullerenes
acceptors
in
organic
photovoltaic
cells
(OPVs).
However,
the
aggregation
tendencies
rapid
excimer
formation
of
PDIs
hindered
their
efficiency
OPVs.
To
address
this
issue
enhance
solubility
while
fine-tuning
electronic
properties,
researchers
explored
fluorination
strategies.
In
study,
we
investigate
structure–function
relationship
two
crystalline
N,N-bis(2′,2′,3′,3′,4′,4′,5′,5′,6′,6′,7′,7′,8′,8′,8′-pentadecafluorooctan-1-yl)perylene(3,4:9,10)bis(dicarboximide)
(FPDI)
polymorphs,
namely,
FPDI-α
FPDI-β.
Their
crystal
structures
show
that
π
systems
FPDI
molecules
adopt
an
orthogonal
geometry,
those
FPDI-β
are
parallel
slip-stacked.
We
report
excited
state
dynamics
using
transient
absorption
fluorescence
microscopy
time-resolved
electron
paramagnetic
resonance
spectroscopy.
Upon
photoexcitation,
both
polymorphs
exhibit
a
lowest
singlet
(S1)
with
substantial
charge
transfer
(CT)
character.
This
S1-CT
decays
τ
=
350
ps
form
triplet
via
spin–orbit
charge-transfer
intersystem
crossing
near-quantitative
yield,
back
ground
140
ps.
study
illustrates
influence
different
packing
motifs
on
photoinduced
intermolecular
CT
processes
single
crystals
same
molecule
contributes
understanding
role
optimizing
PDI-based
molecular
materials
for
solid
state.
Advanced Optical Materials,
Год журнала:
2024,
Номер
12(18)
Опубликована: Май 17, 2024
Abstract
The
intrinsic
quantum
nature
of
molecules
opens
exciting
opportunities
for
developing
the
field
information
science.
In
this
context,
porphyrins
stand
out
as
ideal
building
blocks
technologies
thanks
to
their
unique
optical
and
electrical
properties
well
capacity
accommodate
metal
atoms
ions.
This
review
bridges
chemistry
physics
porphyrins,
providing
an
overview
recent
advances
in
porphyrin‐based
molecular
qubits.
Starting
from
qubits,
explores
potential
porphyrin
units
combine,
leading
formation
logic
gates
hierarchical
higher‐dimensional
structures.
Next,
exploitation
porphyrins'
photophysical
realizing
long‐lived
high
spin
states
is
examined.
These
are
promising
photogeneration
multi‐level
systems
initialization
control
With
a
critical
eye
on
current
state‐of‐the‐art,
elucidates
future
perspectives
advancing
technologies.
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
unknown
Опубликована: Сен. 27, 2024
Optical-spin
interfaces
that
enable
the
photoinitialization,
coherent
microwave
manipulation,
and
optical
read-out
of
ground
state
spins
have
been
studied
extensively
in
solid-state
defects
such
as
diamond
nitrogen
vacancy
(NV)
centers
are
promising
for
quantum
information
science
applications.
Molecular
bits
(qubits)
offer
many
advantages
over
spin
through
synthetic
control
their
properties
scalability
into
well-defined
multiqubit
arrays.
In
this
work,
we
report
an
optical-spin
interface
organic
molecular
qubit
consisting
two
luminescent
tris(2,4,6-trichlorophenyl)methyl
(TTM)
radicals
connected
via
Journal of the American Chemical Society,
Год журнала:
2024,
Номер
unknown
Опубликована: Дек. 16, 2024
Photoexcited
organic
chromophores
appended
to
molecular
qubits
can
serve
as
a
source
of
spin
initialization
or
multilevel
qudit
generation
for
quantum
information
applications.
So
far,
this
approach
has
been
primarily
investigated
in
chromophore–stable
radical
systems.
Here,
we
extend
concept
meso-meso
linked
oxovanadium(IV)
porphyrin–free-base
porphyrin
dimer.
Femtosecond
transient
absorption
experiments
reveal
that
photoexcitation
the
free-base
leads
picosecond
triplet
state
formation
via
enhanced
intersystem
crossing.
Time-resolved
electron
paramagnetic
resonance
(TREPR)
carried
out
at
both
85
K
and
room
temperature
long-lived
spin-polarized
quartet
through
triplet–doublet
mixing.
Notably,
distinct
hyperfine
structure
arising
from
interaction
between
vanadyl
nucleus
(51V,
I
=
7/2)
is
evident,
with
showing
polarization
even
temperature.
Theoretical
simulations
TREPR
spectra
confirm
photogenerated
provide
insights
into
non-Boltzmann
populations.
Exploiting
phenomenon
affords
possibility
using
photoinduced
states
porphyrins
resource
polarize
magnetically
couple
electronic
nuclear
qudits.
Chemical Science,
Год журнала:
2024,
Номер
15(20), С. 7515 - 7523
Опубликована: Янв. 1, 2024
Photoexcited
chromophore–radical
dyads
are
suitable
for
applications
in
molecular
spintronics.
We
show
that
the
position
of
attachment
radical
to
chromophore
can
be
used
as
a
means
tune
their
optical
and
magnetic
properties.