Advanced Synthesis and Catalysis, Volume 348, Issue 6 , Pages 609 - 679
' | |
On the Nature of the Active Species in Palladium Catalyzed Mizoroki-Heck and Suzuki-Miyaura Couplings - Homogeneous or Heterogeneous Catalysis, A Critical Review | |
Tạp chí Advanced Synthesis & Catalysis 2006 ; 348 (6):609 - 679 | |
Tác giả | Nam T. S. Phan, Matthew Van Der Sluys, and Christopher W. Jones |
Nơi thực hiện |
School
of
Chemical
&
Biomolecular
Engineering
Georgia Institute of Technology, Atlanta, GA 30332, USA |
Từ khóa | homogeneous, heterogeneous, colloidal particles, 3-phase test, leaching, C-C coupling |
DOI URL [ PDF] |
English[sửa]
Abstract
A
wide
array
of
forms
of
palladium
have
been
utilized
as
precatalysts
for
Heck
and
Suzuki
coupling
reactions
over
the
last
15
years.
Historically,
nearly
every
form
of
palladium
used
has
been
described
as
the
active
catalytic
species.
However,
recent
research
has
begun
to
shed
light
on
the
in-situ
transformations
that
many
palladium
precatalysts
undergo
during
and
before
the
catalytic
reaction
and
there
are
now
many
suggestions
in
the
literature
that
narrow
the
scope
of
types
of
palladium
that
may
be
considered
true
“catalysts”
in
these
coupling
reactions.
In
this
work,
for
each
type
of
precatalyst,
the
recent
literature
is
summarized
and
the
type(s)
of
palladium
that
are
proposed
to
be
truly
active
are
enumerated.
All
forms
of
palladium,
including
discrete
soluble
palladium
complexes,
solid-supported
metal
ligand
complexes,
supported
palladium
nano
and
macroparticles,
soluble
palladium
nanoparticles,
soluble
ligand-free
palladium,
and
palladium-exchanged
oxides
are
considered
and
reviewed
here.
A
considerable
focus
is
placed
on
solid
precatalysts
and
evidence
for
and
against
catalysis
by
solid
surfaces
vs.
soluble
species
when
starting
with
various
precatalysts.
The
review
closes
with
a
critical
overview
of
various
control
experiments
or
tests
that
have
been
used
by
authors
to
assess
the
homogeneity
or
heterogeneity
of
catalyst
systems.
Outline:
1. Introducton
2. Mechansim
3. Homogeneous Precatalysts
3.1 Homogeneous Precatalysts with N, O, P or S Donor Ligands
3.2 “Naked” Homogeneous Precatalysts
3.3 Palladacycle-based Homogeneous Precatalysts
3.4 N-Heterocyclic Carbene Containing Precatalysts
4. Heterogeneous Precatalysts
4.1 Pd(0) Particles on Oxide or Carbon Supports
4.2 Pd(II) Exchanged Supports
4.3 Supported Metal-ligand Complexes
4.4 Soluble or Polymer Nanosphere Supported Pd Nanoparticle Precatalysts
4.5 Polymer or Oxide “Encapsulated” Precatalysts
5. Distinguishing Between Soluble vs. Insoluble, Molecular vs. Nanoparticle Catalysts
6. Summary and Conclusions
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