Abstract
The
propensity
of
the
π‐electron
system
lying
above
a
polycyclic
aromatic
to
engage
in
halogen
bond
is
examined
by
DFT
calculations.
Prototype
Lewis
acid
CF
3
I
placed
planes
benzene,
naphthalene,
anthracene,
phenanthrene,
naphthacene,
chrysene,
triphenyl,
pyrene,
and
coronene.
atom
positions
itself
some
3.3–3.4
Å
plane,
associated
interaction
energy
about
4
kcal/mol.
This
quantity
little
smaller
for
but
roughly
equal
larger
polycyclics.
only
oscillates
as
slides
across
face
polycyclic,
preferring
regions
higher
density
over
minima
electrostatic
potential.
binding
dominated
dispersion
which
contributes
half
total
energy.
The Journal of Physical Chemistry A,
Год журнала:
2024,
Номер
128(8), С. 1477 - 1490
Опубликована: Фев. 19, 2024
Computational
quantum
chemical
techniques
were
utilized
to
systematically
examine
how
electron-donating
groups
affect
the
electronic
and
spectroscopic
properties
of
halogen
bond
donors
their
corresponding
complexes.
Unlike
majority
studies
on
bonding,
where
electron-withdrawing
are
utilized,
this
work
investigates
influence
substituents
within
donors.
Statistical
analyses
performed
descriptors
in
a
prescribed
set
archetype,
halo-alkyne,
halo-benzene,
halo-ethynyl
benzene
systems.
The
σ-hole
magnitude,
binding
interaction
energies,
vibrational
X···N
local
force
constant
(where
X
=
Cl,
Br,
I,
At)
found
correlate
very
well
monotonic
linear
manner
with
all
other
studied.
In
addition,
enhanced
bonds
when
systems
contained
that
could
form
intramolecular
hydrogen
electronegative
belt
atom
adjacent
linker
features.
The Journal of Physical Chemistry A,
Год журнала:
2023,
Номер
127(21), С. 4695 - 4703
Опубликована: Май 20, 2023
Quantum
calculations
study
the
potential
of
an
intramolecular
H-bond
between
halogen
atom
(X)
a
halobenzene
and
substituent
placed
ortho
to
it,
amplify
ability
X
engage
in
bond
(XB)
with
Lewis
base.
H-bonding
substituents
NH2,
CH2CH2OH,
CH2OH,
OH,
COOH
were
added
halobenzenes
(X
=
Cl,
Br,
I).
The
amino
group
had
little
effect,
but
those
containing
OH
increased
CX···N
XB
energy
NH3
nucleophile
by
about
0.5
kcal/mol;
increment
associated
is
larger,
nearly
2
kcal/mol.
These
increments
approximately
doubled
if
two
such
are
present.
Combining
pair
groups
electron-withdrawing
NO2
para
position
has
particularly
large
raising
4
kcal/mol,
which
can
amount
as
much
4-fold
magnification.
Molecules,
Год журнала:
2023,
Номер
28(22), С. 7520 - 7520
Опубликована: Ноя. 10, 2023
The
relationship
between
the
strength
of
a
halogen
bond
(XB)
and
various
IR
NMR
spectroscopic
quantities
is
assessed
through
DFT
calculations.
Three
different
Lewis
acids
place
Br
or
I
atom
on
phenyl
ring;
each
paired
with
collection
N
O
bases
varying
electron
donor
power.
weakest
XBs
display
C–X
contraction
coupled
blue
shift
in
associated
frequency,
whereas
reverse
trends
occur
for
stronger
bonds.
best
correlations
XB
interaction
energy
are
observed
shielding
C
directly
bonded
to
X
coupling
constants
involving
C–H/F
that
lies
ortho
substituent,
but
these
not
accurate
enough
quantitative
assessment
energy.
These
tend
improve
as
acid
becomes
more
potent,
which
makes
wider
range
strengths.
Journal of the American Chemical Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Март 4, 2025
Proton
NMR
is
a
ubiquitous
and
valuable
probe
of
hydrogen
bonds.
Conversely,
127I
strong
halogen
bond
(XB)
donors
hopeless
due
to
quadrupolar
coupling
constants
(CQ)
on
the
order
GHz.
We
report
here
an
innovative
implementation
Zeeman-perturbed
nuclear
quadrupole
resonance
(Zp-NQR)
spectroscopy,
employing
adjustable
magnetic
fields
mT,
which
renders
possible
acquisition
analysis
spectra
79Br
nuclei
subject
couplings
up
2.3
GHz
in
solid
powders.
This
approach
demonstrated
three
series
halogen-bonded
cocrystals
based
so-called
"iconic"
XB
p-diiodotetrafluorobenzene,
sym-trifluorotriiodobenzene,
p-dibromotetrafluorobenzene
(27
compounds).
Analysis
using
diagonalization
Zeeman-quadrupolar
Hamiltonian
provides
CQ
values
asymmetry
parameters,
thereby
overcoming
various
limitations
encountered
pure
NQR.
Inspection
data
reveals
correlations
with
geometrical
structural
features
bond,
including
its
length.
Dispersion-corrected
zeroth-order
regular
approximation
relativistic
DFT
computations
interaction
energies
donor
are
strongly
correlated
experimental
computed
CQ(127I)
CQ(79Br).
It
concluded
that
electric
field
gradient
at
site
useful
metric
for
quantifying
strength
solids.
The
range
from
∼5
10
kcal
mol-1
systems
studied
herein.
Zp-NQR
amenable
widespread
application
diverse
problems
chemical
materials
sciences
related
energy
materials,
crystal
engineering,
many
comprising
isotopes.
Physical Chemistry Chemical Physics,
Год журнала:
2023,
Номер
25(10), С. 7184 - 7194
Опубликована: Янв. 1, 2023
It
is
usually
expected
that
formation
of
a
halogen
bond
(XB)
requires
region
positive
electrostatic
potential
associated
with
σ
or
π-hole
on
the
Lewis
acid
will
interact
negative
base,
either
lone
pair
π-bond
region.
Quantum
calculations
model
systems
suggest
this
not
to
be
necessary.
The
placement
electron-withdrawing
substituents
base
can
reverse
sign
in
its
positive,
and
nonetheless
engage
XB
σ-hole
acid.
scenario
also
possible
certain
circumstances,
as
negatively
charged
form
base.
Despite
these
classical
Coulombic
repulsions,
overall
interaction
attractive
XBs,
albeit
only
weakly
so.
strengths
bonds
are
surprisingly
insensitive
changes
partner
molecule.
For
example,
even
wide
range
depth
approaching
yields
minimal
change
strength
potential.
Physical Chemistry Chemical Physics,
Год журнала:
2023,
Номер
25(13), С. 9636 - 9647
Опубликована: Янв. 1, 2023
Complexes
of
imidazol-2-ylidene
with
X
2
,
HCCX
and
XCN
(X
is
a
halogen
centre)
are
linked
by
bonds
which
possess
partly
covalent
character.
In
extreme
cases
complexes
the
halonium
cation
transfer
to
Lewis
base
observed.
Polymer-Plastics Technology and Materials,
Год журнала:
2024,
Номер
64(1), С. 88 - 104
Опубликована: Авг. 8, 2024
This
state-of-the-art
overview
highlights
the
significance
of
high
performance
shape
memory
polymer/nanodiamond
nanocomposites.
Nanodiamond
reinforced
polymeric
nanocomposites
have
been
designed
and
advantageously
studied
for
design,
microstructure,
physical
properties,
structure–property
relation/phenomenon,
effects,
possible
technical
advancements.
filled
polymer
matrices
effects
include
polyesters,
polyurethane,
poly(N-isopropylacrylamide),
epoxy,
polyaniline,
chitosan,
etc.
Addition
nanodiamond
especially
functional
nanoparticles
may
develop
and/or
covalent
interactions
with
to
form
interlinking/cross-linking
network
responsible
active
fixing/recovery
behavior.
Noteworthy
thermo-responsive,
electroactive,
photoactive,
photothermal,
magnetic
sensitive
observed.
Application
areas
observed
so
far
are
smart
strain
sensing
wearable
electronics,
antibacterial
biosensing,
civil
engineering
related
areas.
