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.
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.
ChemPlusChem,
Journal Year:
2023,
Volume and Issue:
88(10)
Published: Sept. 7, 2023
Kinetic
data
based
on
1
H
NMR
monitoring
and
computational
studies
indicate
that
in
solution,
pyrazole-containing
iodonium
triflates
silver(I)
triflate
bind
to
each
other,
such
an
interplay
results
the
decrease
of
total
catalytic
activity
mixture
these
Lewis
acids
compared
separate
catalysis
Schiff
condensation,
imine-isocyanide
coupling,
or
nucleophilic
attack
a
triple
carbon-carbon
bond.
Moreover,
kinetic
cooperation
with
prevention
decomposition
salts
during
reaction
progress.
XRD
study
confirms
coordinates
center
via
pyrazole
N
atom
produce
rare
example
pentacoordinated
trigonal
bipyramidal
dinuclear
complex
featuring
cationic
ligands.
Chemistry - A European Journal,
Journal Year:
2024,
Volume and Issue:
30(19)
Published: Jan. 23, 2024
Abstract
Adducts
between
OsO
4
and
Lewis
bases
exert
a
role
in
important
oxidation
processes
such
as
epoxidation
dihydroxylation.
It
has
been
shown
that
the
attractive
interaction
driving
formation
of
these
adducts
is
σ‐hole
bond
involving
metal
electrophilic
species;
term
Osme
Bond
(OmB)
was
proposed
for
designating
it.
Here
some
new
various
have
characterized
through
single
crystal
x‐ray
diffraction
(XRD)
computational
studies
(density
functional
theory,
DFT),
confirming
existence
robust
correlation
energy
deformation
tetrahedral
geometry
.
Also,
formed
by
RuO
with
nucleophiles
were
investigated
computationally.
ChemCatChem,
Journal Year:
2024,
Volume and Issue:
16(12)
Published: Feb. 21, 2024
Abstract
The
experimentally
obtained
kinetic
data
has
indicated
the
existence
of
a
synergetic
cocatalytic
effect
provided
by
an
iodonium
salt
in
base‐catalyzed
Knoevenagel
condensation.
diphenyliodonium
triflate
serving
as
halogen
bond‐donating
Lewis
acid
provides
higher
than
zinc(II)
or
triflic
serving,
respectively,
metal
cation‐based
and
Brønsted
acid.
Such
remains
same
for
broad
scope
carbonyl
compounds
covering
aldehydes
featuring
electron‐withdrawing
electron‐donating
substituents,
well
ketone
involved
reaction.
ChemCatChem,
Journal Year:
2024,
Volume and Issue:
unknown
Published: June 15, 2024
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.
Journal of Physical Organic Chemistry,
Journal Year:
2025,
Volume and Issue:
38(3)
Published: Feb. 14, 2025
ABSTRACT
Halogen
bond
donors
are
recognized
as
electrophilic
catalysts
in
reactions
involving
carbonyl
compounds.
This
study
describes
an
unexpected
inhibition
of
the
Knoevenagel
condensation
by
catalyst.
To
elucidate
intricacies
mechanism,
overall
reaction
order
and
rate
constants
were
determined
using
1
H
NMR
spectroscopy,
further
experiments
with
different
nucleophiles
conducted.
The
findings
revealed
that
primary
is
attributed
to
a
substantial
acceleration
side
aldehyde
methanolysis,
which
hinders
formation
final
alkene
product.
