Chemical Reviews,
Journal Year:
2023,
Volume and Issue:
123(16), P. 10468 - 10526
Published: Aug. 9, 2023
Heteroatom-centered
diradical(oid)s
have
been
in
the
focus
of
molecular
main
group
chemistry
for
nearly
30
years.
During
this
time,
diradical
concept
has
evolved
and
shifted
to
rational
design
specific
applications.
This
review
article
begins
with
some
important
theoretical
considerations
tetraradical
concept.
Based
on
these
considerations,
terms
ligand
choice,
steric,
symmetry,
electronic
situation,
element
reactivity
is
highlighted
examples.
In
particular,
heteroatom-centered
reactions
are
discussed
compared
closed-shell
such
as
pericyclic
additions.
The
comparison
between
reactivity,
which
proceeds
a
concerted
manner,
open-shell
stepwise
fashion,
along
diradical(oid)
design,
provides
understanding
interesting
unusual
class
compounds.
application
diradical(oid)s,
example
small
molecule
activation
or
switches,
also
highlighted.
final
part
application-related
details
spectroscopy
followed
by
an
update
tetraradical(oid)s
published
last
10
years
since
2013.
Angewandte Chemie International Edition,
Journal Year:
2024,
Volume and Issue:
63(20)
Published: March 5, 2024
Abstract
Lead‐based
radicals
in
the
oxidation
state
of
+1
are
elusive
species
and
highly
challenging
to
isolate
condensed
phase.
In
this
study,
we
present
synthesis
characterization
first
isolable
free
plumbylyne
radical
2
bearing
a
one‐coordinate
Pb(I)
atom.
It
reacts
with
an
N
‐heterocyclic
carbene
(NHC)
afford
two‐coordinate
NHC‐ligated
3
.
represent
Pb(I)‐based
radicals.
Theoretical
calculations
electron
paramagnetic
resonance
analysis
revealed
that
unpaired
mainly
resides
at
Pb
6p
orbital
both
Owing
unique
nature
atom
,
it
possesses
two‐fold
pseudo‐degeneracy
substantial
unquenched
angular
momentum,
exhibits
hitherto
strongest
g
‐factor
anisotropy
(
x,y,z
=1.496,
1.166,
0.683)
amongst
main
group
Preliminary
investigations
into
reactivity
unveiled
its
Pb‐centered
nature,
plumbylenes
were
isolated
as
products.
National Science Review,
Journal Year:
2023,
Volume and Issue:
10(10)
Published: June 10, 2023
Isolation
of
triplet
pnictinidenes,
which
bear
two
unpaired
electrons
at
the
pnictogen
centers,
has
long
been
a
great
challenge
due
to
their
intrinsic
high
reactivity.
Herein,
we
report
syntheses
and
characterizations
bismuthinidenes
MsFluindtBu-Bi
(3)
MsFluind*-Bi
(4)
stabilized
by
sterically
encumbered
hydrindacene
ligands.
They
were
facilely
prepared
through
reductions
corresponding
dichloride
precursors
with
2
molar
equivalents
potassium
graphite.
The
structural
analyses
revealed
that
3
4
contain
one-coordinate
bismuth
atom
supported
Bi-C
single
σ
bond.
As
consequence,
remaining
Bi
6p
orbitals
are
nearly
degenerate,
possess
ground
states.
Experimental
multinuclear
magnetic
resonance,
magnetometry
near
infrared
spectroscopy
coupled
wavefunction
based
ab
initio
calculations
concurred
evidence
there
exist
giant
positive
zero
field
splittings
(>4300
cm-1)
in
S
=
1
Hence
even
room
temperature
systems
almost
exclusively
populate
lowest-energy
nonmagnetic
Ms
0
level,
renders
them
seemingly
diamagnetic.
Nature Communications,
Journal Year:
2024,
Volume and Issue:
15(1)
Published: May 29, 2024
Abstract
Phosphanorcaradienes
are
an
appealing
class
of
phosphorus
compounds
that
can
serve
as
synthons
transient
phosphinidenes.
However,
the
synthesis
such
species
is
a
formidable
task
owing
to
their
intrinsic
high
reactivity.
Herein
we
report
straightforward
synthesis,
characterization
and
reactivity
studies
phosphanorcaradiene,
in
which
one
benzene
rings
flanking
fluorenyl
substituents
intramolecularly
dearomatized
through
attachment
atom.
It
facilely
obtained
by
reduction
phosphorus(III)
dichloride
precursor
with
potassium
graphite.
Despite
being
thermally
robust,
it
acts
synthetic
equivalent
phosphinidene.
reacts
trimethylphosphine
isonitrile
yield
phosphanylidene-phosphorane
1-phospha-3-azaallene,
respectively.
When
treated
two
molar
equivalents
azide,
iminophosphane
bis(imino)phosphane
isolated,
Moreover,
capable
activating
ethylene
alkyne
afford
[1
+
2]
cycloaddition
products,
well
oxidative
cleavage
Si–H
N–H
bonds
secondary
phosphines.
All
reactions
proceed
smoothly
at
room
temperature
without
presence
transition
metals.
The
driving
force
for
these
most
likely
ring-constraint
three-membered
PC
2
ring
recovery
aromaticity
ring.
Chinese Journal of Chemistry,
Journal Year:
2023,
Volume and Issue:
42(7), P. 736 - 742
Published: Nov. 27, 2023
Comprehensive
Summary
Reduction
of
chlorogermylene
M
s
Fluind
t
Bu
‐GeCl
1
with
potassium
graphite
(KC
8
)
afforded
putative
germylyne
radical
‐Ge
2
as
confirmed
by
electron
paramagnetic
resonance
(EPR)
spectroscopy.
However,
it
slowly
decayed
via
C—H
bond
activation
at
the
fluorenyl
moiety
to
yield
a
bis(germylene)
3
room
temperature.
By
using
Lewis
base
stabilize
unoccupied
p
orbital
Ge
I
center,
acyclic
two‐coordinate
radicals
‐Ge(I
Me4
4
(I
=
1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene),
i
Pr
5
1,3‐diisopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene),
‐Ge(PMe
6
were
isolated
in
crystalline
forms.
The
unpaired
—
mainly
resides
4p
revealed
EPR
spectroscopic
studies
and
theoretical
calculations.
Interestingly,
facile
ligand
exchange
PMe
was
observed
afford
,
respectively.
Moreover,
phosphinogermylyne
reacted
PhEEPh
(E
S,
Se),
4‐tetrabutylphenylacetylene
(Ar'CCH),
[CpMo(CO)
]
n
SnH
furnish
germylenes
‐GeEPh
S
7
Se
),
‐GeCH=CHAr’
9
complex
‐Ge≡Mo(CO)
Cp
10
Ge(IV)
compound
‐GeH
Sn
11
reactivity
demonstrate
that
can
act
synthon
one‐coordinate
attributing
labile
coordination
trimethylphosphine.
JACS Au,
Journal Year:
2025,
Volume and Issue:
5(2), P. 1016 - 1030
Published: Feb. 6, 2025
The
fascinating
magnetic
and
catalytic
properties
of
coordinatively
unsaturated
3d
metal
complexes
are
a
manifestation
their
electronic
structures,
in
particular
nearly
doubly
or
triply
degenerate
orbital
ground
levels.
Here,
we
propose
criterion
to
determine
the
degree
degeneracy
this
class
based
on
experimentally
accessible
anisotropy
(parametrized
by
electron
spin
g-
zero-field
splitting
(ZFS)-tensors).
is
derived
from
comprehensive
spectroscopic
theoretical
study
trigonal
planar
iron(0)
complex,
[(IMes)Fe(dvtms)]
(IMes
=
1,3-di(2′,4′,6′-trimethylphenyl)imidazol-2-ylidene,
dvtms
divinyltetramethyldisiloxane,
1).
Accurate
ZFS-values
(D
+33.54
cm–1,
E/D
0.09)
g-values
(g∥
1.96,
g⊥
2.45)
triplet
(S
1)
level
complex
1
were
determined
complementary
THz-EPR
spectroscopy
SQUID
magnetometry.
In-depth
effective
Hamiltonian
(EH)
analyses
coupled
wave-function-based
ab
initio
calculations
show
that
features
with
three
energetically
close-lying
states
"two-above-one"
energy
pattern.
observed
results
mixing
two
excited
state
spin–orbit
coupling
(SOC).
EH
investigations
related
allowed
us
generalize
finding
establish
ZFS-tensors
as
markers
for
assigning
two-
three-fold
near-degeneracy.
Journal of the American Chemical Society,
Journal Year:
2025,
Volume and Issue:
unknown
Published: March 10, 2025
Nitroso
compounds,
R-N═O,
containing
N═O
double
bonds
are
ubiquitous
and
widely
utilized
in
organic
synthesis.
In
contrast,
heavier
congeners
of
nitroso
namely
pnictinidene
chalcogenides
R-Pn
=
E
(Pn
P,
As,
Sb,
Bi;
O,
S,
Se,
Te),
highly
reactive
scarce.
They
have
been
stabilized
the
coordination
sphere
Lewis
acid/base
or
by
pronounced
contribution
from
resonance
structures,
whereas
free
species
with
unperturbed
pnictogen-chalcogen
remains
elusive.
this
work,
we
report
isolation
characterization
arylstibinidene
chalcogenides,
which
first
aromatic
compounds.
facilely
synthesized
through
salt
metathesis
reactions
aryldichlorostibane
dilithium
chalcogenides.
bear
Sb═E
(E
Se
Te)
due
to
poor
orbital
overlap
between
C
2p
orbitals
phenyl
ring
substituent
Sb
5p
orbitals.
Moreover,
they
show
versatile
reactivity,
including
acting
as
chalcogen
atom
transfer
reagents
reacting
small
molecules
via
(cyclo)addition.
