%0 Journal Article
%A Groen, Johannes H.
%A G. P. Delis, Johannes
%A W. N. M. van Leeuwen, Piet
%A Vrieze, Kees
%D 1997
%T Kinetic Study of the Insertion of Norbornadiene into
Palladium−Carbon Bonds of Complexes Containing the
Rigid Bidentate Nitrogen Ligand
Bis(arylimino)acenaphthene
%U https://acs.figshare.com/articles/journal_contribution/Kinetic_Study_of_the_Insertion_of_Norbornadiene_into_Palladium_Carbon_Bonds_of_Complexes_Containing_the_Rigid_Bidentate_Nitrogen_Ligand_Bis_arylimino_acenaphthene/3778692
%R 10.1021/om960789f.s001
%2 https://acs.figshare.com/ndownloader/files/5889585
%K 2 C 6 H 3
%K BIAN ligand
%K contact ion pair
%K alkene association
%K alkene insertion
%K nitrogen dissociation
%K alkene concentration
%K k 1
%K k 2
%K k 2 pathways
%K BrC 6 H 4
%K k 2 pathway
%K k 1 pathway
%K rate law k obsd
%K rate constants k 1
%K FC 6 H 4
%X The ionic
[Pd(C7H8C(O)R)(Ar-BIAN)]X (R
= Me, Et, iPr, Ph; X = Cl, Br, I; Ar =
p-An,
p-FC6H4,
p-BrC6H4, p-Tol, Ph,
o,o‘-Me2C6H3,
o,o‘-iPr2C6H3)
complexes (1b−12b), bearing the
bidentate nitrogen ligand bis(arylimino)acenaphthene
(Ar-BIAN), have been synthesized via
reaction of the corresponding neutral acylpalladium complexes
Pd(C(O)R)X(Ar-BIAN) (1a−12a) with norbornadiene (nbd). For the first time, an
extensive kinetic study of this migratory
alkene insertion into acyl−palladium bonds of neutral complexes
containing α-diimine ligands
has been carried out. It has been found that under
pseudo-first-order circumstances these
reactions follow the rate law kobsd =
k1 + k2[nbd],
which shows that these reactions proceed
via a pathway independent of alkene concentration
(k1 pathway) and a pathway
dependent
on alkene concentration (k2 pathway). The
dramatic decrease of the rate constants k1
and
k2 upon increasing the steric bulk of the BIAN
ligand and the large negative entropy of
activation and low enthalpy of activation for both pathways indicate
that the k1 and
k2
pathways are closely related and involve associative processes.
From the influence of solvent,
X and C(O)R ligand, steric and electronic properties of the BIAN
ligand, the presence of
free halide and free BIAN, and the parameters of activation, mechanisms
have been proposed
for both pathways. The k1 pathway may
proceed via a rate-determining solvent-assisted
halide or nitrogen dissociation, followed by alkene association and
migratory insertion, while
the k2 pathway may occur via a rate-determining
migratory alkene insertion in a contact
ion pair intermediate. This species may be formed via alkene
association followed by either
halide or nitrogen dissociation.
%I ACS Publications