Macromolecular Rapid Communications,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 22, 2024
Abstract
The
origin
of
stereocontrol
in
ring
opening
polymerization
(ROP)
racemic
lactide
(
rac
‐LA)
promoted
by
achiral
aluminium‐based
catalysts
has
been
explained
through
DFT
calculations
combined
with
a
molecular
descriptor
(%
V
Bur
)
and
the
activation
strain
model
(ASM‐NEDA)
analysis.
proposed
chain
end
control
(CEC)
suggests
that
ligand
framework
adopts
chiral
configuration
mimicking
enantiomorphic
site
(ESC)
while
also
incorporating
last
inserted
monomer
unit.
It
is
found
wrapping
mode
around
aluminium
centre
dictated
R
,
‐LA
S
‐LA).
A
good
correlation
experimental
data
achieved
only
when
accounting
for
dynamic
features
its
steric
influences,
as
highlighted
%
maps
ASM‐NEDA
Understanding
ESC
CEC
interplay
an
important
target
obtaining
stereoselective
ROP
synthesis
biodegradable
materials
tailored
properties.
Applied Organometallic Chemistry,
Год журнала:
2024,
Номер
38(12)
Опубликована: Авг. 29, 2024
ABSTRACT
The
development
of
hydrogenation
processes
for
polyalphaolefin
(PAO)
lubricants,
which
hold
commercialization
potential,
is
a
challenging
endeavor.
Here,
we
synthesized
and
characterized
rod‐shaped
γ‐alumina
supported
Pd
catalyst
PAO
hydrofinishing,
comparing
it
with
Ni
catalyst.
Results
indicated
that
Pd/Al
2
O
3
efficiently
promoted
whereas
Ni‐based
exhibited
lower
activity.
Optimization
reaction
variables
using
the
one‐factor‐at‐a‐time
method
revealed
hydrogenated
could
be
achieved
90%
yield
5
wt.%
catalyst,
hydrogen
pressure
12
bar,
at
130°C
after
7
h.
superior
performance
fabricated
catalysts,
coupled
use
alumina
suitable
large‐scale
reactors,
suggests
versatility
process
potential
commercialization.
Additionally,
higher
Pd/alumina
compared
to
Ni/alumina
was
computationally
assessed
molecular
level
DFT
methods.
The Journal of Physical Chemistry C,
Год журнала:
2024,
Номер
128(36), С. 14961 - 14971
Опубликована: Сен. 2, 2024
Nature's
enzymes
exhibit
remarkable
substrate
specificity
and
catalytic
efficiency
by
transforming
substrates
within
confined
active
sites.
To
emulate
this,
various
molecular
containers,
including
zeolites,
cyclodextrins,
calix[n]arenes,
cavitands,
cucurbit[n]urils,
metal–organic
frameworks,
covalent
organic
carbon
nanotubes
(CNTs),
have
been
explored.
Among
these,
CNTs
are
notable
for
their
unique
physical
chemical
properties,
enabling
them
to
control
reactions
through
spatial
confinement.
This
study
investigates
the
effect
of
CNT
encapsulation
on
metal-free
1,3-dipolar
Huisgen
cycloaddition
between
benzyl
azide
substituted
alkynes.
Experimental
results
showed
that
significantly
enhance
selectivity
1,4-triazole
product.
Computational
studies
using
density
functional
theory
further
elucidate
impact
confinement
reaction
mechanisms
regioselectivity.
The
findings
reveal
alters
potential
energy
surfaces,
favoring
formation
over
1,5-triazole,
driven
steric
electronic
factors.
Additionally,
comparative
analyses
highlight
influence
diameter
activation
energies
product
stability,
particularly
with
decomposition
analysis
noncovalent
interaction
plots.
research
underscores
as
nanoscale
reactors
controlled
synthesis,
providing
insights
into
design
new
systems
advancing
field
selective
transformations.
Macromolecular Rapid Communications,
Год журнала:
2024,
Номер
unknown
Опубликована: Окт. 22, 2024
Abstract
The
origin
of
stereocontrol
in
ring
opening
polymerization
(ROP)
racemic
lactide
(
rac
‐LA)
promoted
by
achiral
aluminium‐based
catalysts
has
been
explained
through
DFT
calculations
combined
with
a
molecular
descriptor
(%
V
Bur
)
and
the
activation
strain
model
(ASM‐NEDA)
analysis.
proposed
chain
end
control
(CEC)
suggests
that
ligand
framework
adopts
chiral
configuration
mimicking
enantiomorphic
site
(ESC)
while
also
incorporating
last
inserted
monomer
unit.
It
is
found
wrapping
mode
around
aluminium
centre
dictated
R
,
‐LA
S
‐LA).
A
good
correlation
experimental
data
achieved
only
when
accounting
for
dynamic
features
its
steric
influences,
as
highlighted
%
maps
ASM‐NEDA
Understanding
ESC
CEC
interplay
an
important
target
obtaining
stereoselective
ROP
synthesis
biodegradable
materials
tailored
properties.
