Combination
of
experimental
data
and
results
DFT
calculations
indicates
that
the
catalytic
activity
chalconium
halonium
salts
served
as
sigma-hole
donating
organocatalysts
cannot
be
clearly
estimated
via
analysis
electrostatic
potential
on
catalysts’
sigma-holes
values
catalyst•••TS
intermolecular
interactions,
such
polarization
effects,
charge
transfer,
or
covalency
bonding.
Moreover,
real
effect
might
not
correlate
well
with
Gibbs
free
energies
activation
reactions,
because
solvation
effects
other
competitive
binding
processes
play
at
least
same
even
more
important
role
in
catalysis.
It
was
showed
present
work,
either
can
lead
to
increase
equilibrium
concentration
reactive
catalyst•••electrophile
associates
thus
accelerating
reaction
brings
favorable
generation
catalyst•••nucleophile
species
resulting
suppression
organocatalyst.
ACS Catalysis,
Год журнала:
2023,
Номер
13(5), С. 3272 - 3284
Опубликована: Фев. 20, 2023
Controlling
polymer
tacticity
is
a
key
consideration
in
macromolecular
synthesis
due
to
the
impact
of
stereochemistry
on
material's
thermomechanical
and
optical
properties.
Recently,
inspired
by
work
small
molecule
catalysis,
asymmetric
ion-pairing
has
emerged
as
valuable
approach
control
polymers
made
through
chain
growth
polymerization
vinyl
monomers.
This
Perspective
outlines
some
challenges
inherent
stereocontrol
well
highlights
recent
catalyst
development
area
that
enabled
both
configuration
conformation
polymers.
Several
synthetic
opportunities
mechanistic
questions
have
been
identified
will
expand
synthesis.
The Journal of Organic Chemistry,
Год журнала:
2024,
Номер
89(5), С. 2916 - 2925
Опубликована: Фев. 19, 2024
Sulfonium,
selenonium,
telluronium,
and
iodonium
cyanoborohydrides
have
been
synthesized,
isolated,
fully
characterized
by
various
methods,
including
single-crystal
X-ray
diffraction
(XRD)
analysis.
The
quantum
theory
of
atoms
in
molecules'
analysis
based
on
the
XRD
data
indicated
that
hydride···σ-hole
short
contacts
observed
crystal
structures
each
compound
a
purely
noncovalent
nature.
telluronium
provide
significantly
higher
rate
model
reaction
imine
hydrogenation
compared
with
sodium
tetrabutylammonium
cyanoborohydrides.
Based
NMR
high-resolution
electrospray
ionization
mass
spectrometry
indicating
progress
is
accompanied
cation
reduction,
mechanism
involving
intermediate
formation
elusive
onium
hydrides
has
proposed
as
an
alternative
to
conventional
electrophilic
activation
moiety
its
ligation
cation's
σ-hole.
Organic & Biomolecular Chemistry,
Год журнала:
2022,
Номер
20(38), С. 7632 - 7639
Опубликована: Янв. 1, 2022
This
theoretical
study
sheds
light
on
the
relative
catalytic
activity
of
pnictonium,
chalconium,
and
halonium
salts
in
reactions
involving
elimination
chloride
electrophilic
activation
a
carbonyl
group.
DFT
calculations
indicate
that
for
cationic
aromatic
onium
salts,
values
electrostatic
potential
heteroatom
σ-holes
gradually
increase
from
pnictogen-
to
halogen-containing
species.
The
higher
halogen
atoms
result
overall
these
species,
but
case
pnictonium
chalconium
cations,
weak
interactions
side
groups
provide
an
additional
stabilization
effect
reaction
transition
states.
Based
upon
quantum-chemical
calculations,
phosphonium(V)
arsenonium(V)
is
expected
be
too
low
obtain
effective
noncovalent
organocatalytic
compounds,
whereas
stibonium(V),
telluronium(IV)
iodonium(III)
exhibit
application
as
organocatalysts.
Abstract
Sulfonium,
selenonium,
telluronium
triflates,
as
well
chloronium,
bromonium,
and
iodonium
triflates
have
been
examined
in
the
model
Schiff
condensation
chalcogen‐
halogen
bond
donating
organocatalysts,
respectively.
The
kinetic
data
indicated
that
catalytic
effect
of
salt
is
provided
via
decrease
enthalpy
activation
reaction,
whereas
–
unexpectedly
caused
by
value
entropy
activation.
In
addition,
it
was
experimentally
shown
activity
sulfonium
selenonium
salts
significantly
lower
than
chloronium
bromonium
salts,
but
latter
pair
species
less
stable
under
reaction
conditions
former
pair.
Organic & Biomolecular Chemistry,
Год журнала:
2025,
Номер
unknown
Опубликована: Янв. 1, 2025
Chalconium
and
halonium
salts
catalyze
Schiff
condensation.
Kinetic
data
DFT
calculations
show
that
the
catalytic
activity
correlates
with
maximum
electrostatic
potential
on
σ-holes,
whereas
other
factors
are
less
significant.
Angewandte Chemie International Edition,
Год журнала:
2023,
Номер
62(26)
Опубликована: Апрель 26, 2023
Exploiting
non-covalent
interactions
to
catalyze
challenging
ionic
polymerizations
is
an
ambitious
goal
but
in
its
infancy.
We
recently
demonstrated
anion-binding
catalysis
as
effective
methodology
enable
living
cationic
polymerization
(LCP)
of
vinyl
ethers
environmentally
benign
manner.
Here,
we
further
elucidate
the
structure-reactivity
relationships
elaborately
designed
seleno-cyclodiphosph(V)azanes
catalysts
and
roles
by
a
combined
theoretical
DFT
study
experimental
study.
The
investigation
suggests
that
distinct
cis-cyclodiphosph(V)azane
framework
with
"selenium
effect"
electron-withdrawing
3,5-(CF3
)2
-Phenyl
substitution
pattern
catalyst
enables
critical
contribution
accessing
excellent
stability,
anion
affinity
solubility
under
conditions.
Thus,
could
leverage
precisely
control
reversible
transient
dormant-active
species
equilibrium,
allowing
it
dynamically
bind,
recognize
pre-organize
propagating
monomer,
thereby
facilitating
efficient
chain
propagation
minimizing
irreversible
transfer
events
mild
more
in-depth
understanding
mechanism
for
catalytic
LCP
reported
herein
should
help
guide
future
design
extend
this
concept
broader
systems
where
serve
crucial
intermediates.
