A Blessing and a Curse: Remote Ligand Functionalization Modulates 3MLCT Relaxation in Group 6 Tricarbonyl Complexes
Inorganic Chemistry,
Journal Year:
2025,
Volume and Issue:
unknown
Published: Feb. 25, 2025
We
recently
reported
a
molecular
design
for
carbonylpyridine
molybdenum(0)
complexes
that
unlocks
long-lived
luminescent
and
photoactive
charge-transfer
states.
Here,
we
translate
this
strategy
to
chromium(0),
tungsten(0)
report
three
fully
characterized
tricarbonyl
metal(0)
featuring
tripodal
ligand
with
remote
n-butyl
substituent
in
the
backbone.
All
show
phosphorescence
red
near-infrared
spectral
region
from
metal-to-ligand
excited
Surprisingly,
alkyl
chain
significantly
affects
state
relaxation:
lifetimes
are
shortened
solution
but
extended
solid
by
one
order
of
magnitude
compared
complex
methyl
substituent.
Temperature-dependent
luminescence
NMR
spectroscopy
combination
quantum
chemical
calculations
reveal
reasons
these
disparate
effects.
The
distorts
metal
coordination
geometry.
resulting
structural
flexibility
flattens
potential
energy
surfaces
solution,
which
lowers
barrier
population
distorted
metal-centered
states
facilitates
nonradiative
relaxation.
In
state,
rigidified
separates
neighboring
molecules,
reduces
self-quenching.
Our
study
sheds
light
on
relationship
between
structure
relaxation
inform
development
based
earth-abundant
metals.
Language: Английский
Molecular Design Principles for Photoactive Transition Metal Complexes: A Guide for “Photo-Motivated” Chemists
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 27, 2025
Luminescence
and
photochemistry
involve
electronically
excited
states
that
are
inherently
unstable
therefore
spontaneously
decay
to
electronic
ground
states,
in
most
cases
by
nonradiative
energy
release
generates
heat.
This
dissipation
can
occur
on
a
time
scale
of
100
fs
(∼10–13
s)
usually
needs
be
slowed
down
at
least
the
nanosecond
(∼10–9
for
luminescence
intermolecular
occur.
is
challenging
task
with
many
different
factors
consider.
An
alternative
emerging
strategy
target
dissociative
lead
metal–ligand
bond
homolysis
subnanosecond
access
synthetically
useful
radicals.
Based
thorough
review
recent
advances
field,
this
article
aims
provide
concise
guide
obtaining
luminescent
photochemically
coordination
compounds
d-block
elements.
We
hope
encourage
"photo-motivated"
chemists
who
have
been
reluctant
apply
their
synthetic
other
knowledge
photophysics
photochemistry,
we
intend
stimulate
new
approaches
control
state
behavior.
Language: Английский