Synthesis, Structure, and Reductive Elimination of Cationic Monoarylpalladium(IV) Complexes Supported by a Tripodal Oxygen Ligand

Article abstract of DOI:10.1002/ejic.201700326

Cationic monoaryl–Pd^IV complexes supported by the Kl?ui tripodal ligand [Co(η⁵-C₅H₅){P(O)(OEt)₂}₃]^– (L_OEt^–) were synthesized, and their reductive elimination was studied. Treatment of trans-[Pd(PPh₃)₂(Ar)(I)] and [{Pd(η²-ppytBu)Cl}₂] [ppytBuH = 2-(4-tert-butylphenyl)pyridine] with [AgL_OEt] afforded [Pd(Ar)(PPh₃)(η²-L_OEt)] [Ar = Ph (1), p-tolyl (2)] and [Pd(η²-ppytBu)(η²-L_OEt)] (3), respectively. Chlorination of 1, 2, and 3 with PhICl₂ in the presence of NH₄PF₆ afforded the cationic aryl–Pd^IV chloride complexes [Pd(Ph)(PPh₃)(Cl)(L_OEt)](PF₆) (4), [Pd(p-tolyl)(PPh₃)(Cl)(L_OEt)](PF₆) (5), and [Pd(η²-ppytBu)(Cl)(L_OEt)](PF₆) (6), respectively. Complexes 4 and 5 underwent C(sp²)–Cl elimination at 40 °C in acetonitrile to give a Pd^II–L_OEt species and the corresponding chloroarene. On the other hand, the C(sp²)–Cl elimination of 6 occurred at room temperature and afforded a Pd^II species, presumably [Pd(ClppytBuH)(L_OEt)](PF₆), which further reacted with PhICl₂ to yield [Pd(η²-ClppytBu)Cl(L_OEt)](PF₆) (7) [ClppytBuH = 2-(4-tert-butyl-2-chlorophenyl)pyridine]. The structures of complexes 1, 4, 6, and 7 were established by X-ray crystallography.

Full text of DOI:10.1002/ejic.201700326

A Journal of
Accepted Article
Title: Synthesis, Structure, and Reductive Elimination of Cationic
Palladium(IV) Monoaryl Complexes Supported by a Tripodal
Oxygen Ligand
Authors: Yat-Ming So, Ka-Chun Au-Yeung, Herman H. Y. Sung, Ian D.
Williams, and Wa-Hung Leung
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Eur. J. Inorg. Chem. 10.1002/ejic.201700326
Link to VoR: http://dx.doi.org/10.1002/ejic.201700326

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
Synthesis, Structure, and Reductive Elimination of Cationic Palladium(IV) Monoaryl
Complexes Supported by a Tripodal Oxygen Ligand
[
a]
Yat-Ming So, Ka-Chun Au-Yeung, Herman H.-Y. Sung, Ian D. Williams, and Wa-Hung Leung*
IV
5
-
-
Abstract: Cationic Pd mono-aryl complexes supported by the Kläui tripodal ligand [Co( -C
5 5 2 3
H ){P(O)(OEt) } ] (LOEt ) have been synthesized
2
t
t
and their reductive elimination has been studied. The treatment of trans-[Pd(PPh (Ar)(I)] and [Pd( -ppyBu )Cl] [ppyBu H = 2-(4-tert-
)
3 2
2
2
2
t
2
butylphenyl)pyridine] with [AgLOEt] afforded [Pd(Ar)(PPh
chlorination of 1, and with PhICl
) (4), [Pd(p-tolyl)(PPh
3
)( -LOEt)] (Ar = Ph (1), p-tolyl (2)) and [Pd( -ppyBu )( -LOEt)] (3), respectively. The
IV
2
3
2
in the presence of NH
4
PF
6
2
afforded the cationic Pd
aryl chloride complexes
t
[
Pd(Ph)(PPh
3
)(Cl)(LOEt)](PF
6
3
)(Cl)(LOEt)](PF
6
) (5) and [Pd( -ppyBu )(Cl)(LOEt)](PF
6
) (6), respectively. Complexes 4 and 5
2
o
II
underwent C(sp )-Cl elimination at 40 C in acetonitrile to give a Pd -LOEt species and the corresponding chloroarene. On the other hand, the
2
II
t
6
C(sp )-Cl elimination of 6 occurred at room temperature affording a Pd species, presumably [Pd(ClppyBu H)(LOEt)](PF ), which further reacted
2
t
t
with PhICl
2
to yield [Pd( -ClppyBu )Cl(LOEt)](PF
6
) (7) [ClppyBu H = 2-(4-tert-butyl-2-chlorophenyl)pyridine]. The structures of complexes 1, 4,
6
and 7 have been established by X-ray crystallography.
Introduction
mediated C-H transformations. Of special interest are facially
coordinating tridentate ligands that have proven to be excellent
spectactor ligands for Pd .
IV
IV 2
High-valent organometallic complexes of Pd (especially Pd )
have attracted much attention because of their involvement as
Although Pd-based catalysts in oxygen-rich ligand
environments (e.g. palladium(II) acetate and oxide) are well
reactive intermediates in some Pd-catalyzed organic
1
1,6
IV
transformations. As
a
consequence, there has been an
known, not many well-defined organo-Pd complexes with O-
IV
7
IV
increasing interest in the organometallic chemistry of Pd in the
donor ligands have been synthesized; reported Pd complexes
are mostly supported by N- and C-donor ligands. We are
2
2,8
past decade. In particular, the reductive elimination of well-
IV
defined organo-Pd complexes leading to the formation of
carbon-carbon and carbon-heteroatom bonds has been
investigated extensively (Scheme 1). Also, recent studies have
shown that in addition to reductive elimination, other
particularly interested in the Kläui’s tripodal ligand
-
5
-
[CoCp{P(O)(OEt)
2
}
3
5 5
] (Cp =  -C H ; denoted as LOEt hereafter)
3
(Scheme 2) that is capable of stabilizing metal ions in high
9
oxidation states. Stable high-valent transition metal (e.g.
IV
VI 9b,10a-d
IV 10e
-
fundamental organometallic reactions at the Pd
center,
Ru ),
and lanthanide (Ce )
complexes with LOEt have
including ligand substitution, C−H activation, and migratory
insertion, play key roles in the Pd /Pd catalytic cycles.
been synthesized, suggesting that the {PdLOEt} fragment can
serve as a good platform for the study of Pd organometallic
II
IV
4
IV
II
chemistry. Previously, Kläui and coworkers synthesized Pd
-
2
complexes with bidentate LOR (R = Me, Et) ligands, e.g. [( -
R
X
2
11
IV
Pd
II
Pd
LOMe)Pd(allyl)] and [( -L )Pd(PPh )Cl]. Nevertheless, the
oxdiative addition of these Pd -LOMe complexes has not been
Reductive Elimination
OMe
3
+
R
X
II
IV
reported. The Pd trialkyl complexes [(LOMe)Pd(Me)
obtained by oxidative addtion of [Pd(bpy)Me ] (bpy = 2,2‘-
bipyridine) with RI in the presence of [NaLOme]/[AgLOme];
2
R] were
R = aryl, alkyl
2
12
X = carbene, nitrene, alkoxide, thiolate, alkyl, halide etc.
IV
however, like other Pd trialkyl complexes, [(LOMe)Pd(Me)
2
R] do
IV
Scheme 1. Carbon-carbon and carbon-heteroatom elimination at the Pd
center.
not undergo reductive elimination. To enhance the reactivity of
3
IV
IV
the Pd center, we sought to synthesize LOEtPd mono-aryl
halide complexes. Herein, we describe the synthesis of cationic
IV
II
Pd -LOEt aryl complexes by oxidation of Pd -LOEt complexes with
0
Despite the wealth of organometallic chemistry of Pd and
2
IV
PhICl
2
. The C(sp )-Cl elimination of the Pd aryl chloride
II 5
IV
Pd , the coligand effect on the reactivity of Pd complexes has
not been well explored. Chelating coligands can increase the
complexes has been investigated.
II
IV
electron density of the Pd center, thus facilitating the Pd /Pd
oxidation and enhancing the chemo- and regio-selectivity of Pd-
EtO
EtO
Co
EtO
OEt
OEt
P
P
=
O
O O
OEt
P
O
O
O
-
LOEt
[a]
Dr. Y.-M. So, Dr. K.-C. Au-Yeung, Dr. H. H.-Y. Sung, Prof. I. D.
Williams, Prof. W.-H. Leung
-
Department of Chemistry
Scheme 2. Structure of the Kläui tripodal ligand LOEt .
The Hong Kong University of Science and Technology
Clear Water Bay, Kowloon, Hong Kong (P. R. China)
Fax: (+852) 2356-1594
Results and Discussion
E-mail: chleung@ust.hk
Supporting information for this article is given via a link at the end of
the document.((Please delete this text if not appropriate))
II
Synthesis of Pd -LOEt Complexes
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
1
3
Figure 1. Molecular structure of 1. The ellipsoids are drawn at 30% probability
level. Hydrogen atoms are omitted for clarity. Selected bond lengths (Å) and
angles (°): Pd-O(7) 2.783(2), Pd-O(8) 2.133(2), Pd-O(9) 2.1259(19), Pd-C(15)
Metathesis of trans-[Pd(PPh
AgLOEt] in CH Cl resulted in precipitation of AgI and a yellow
solution, from which air-stable yellow crystals characterized as
3 2
) (Ar)(I)] with 1 equivalent of
[
2
2
1.968(3), Pd-P(4) 2.2025(7); O(8)-Pd-P(4) 97.74(6), O(9)-Pd-P(4) 167.07(6),
2
[
Pd(Ar)(PPh
3
)( -LOEt)] (Ar = Ph (1), p-tolyl (2)) were isolated
Scheme 3). Complexes 1 and 2 are soluble in common organic
solvents including hexanes. Despite the  binding mode of the
OEt ligand (see Figure 1), only one set of ethoxy signals was
O(9)-Pd-O(8) 84.48(8), C(15)-Pd-P(4) 88.64(8), C(15)-Pd-O(8) 173.35(10),
C(15)-Pd-O(9) 89.71(10).
(
2
-
L
1
31
Recent studies have shown that cyclometalated ligands
found in the H NMR spectra of 1 and 2. In addition, the
P
IV
such as 2-phenylpyridine (ppy) are capable of stabilizing Pd
NMR spectra displayed a single peak at ca.  = 108 ppm-
14
complexes. This prompted us to synthesize cyclopalladated
attributable to the three equivalent phosphorus nuclei of LOEt
-
t
complexes supported by LOEt . Treatment of [Pd(ppyBu )Cl]
2
along with the PPh
3
signal, indicating that the bidentate tripodal
ligand is fluxional in solution at room temperature.
t
[
ppyBu H = 2-(4-tert-butylphenyl)pyridine] with 2 equivalents of
AgLOEt] in CH Cl afforded an air-stable yellow crystalline solid
characterized as [Pd(ppyBu )(LOEt)] (3) that presumably contains
[
2
2
t
[
AgLOEt
]
2
an  -LOEt ligand (Scheme 3). Complex 3 has been fully
characterized by NMR spectroscopy and elemental analyses.
t
Pd(PPh ) (Ar)(I)
1/2 [Pd(ppyBu )Cl]
3
2
2
-
AgI
- AgCl
IV
Synthesis of Pd -LOEt Complexes
No oxidative addition was found when 1 or 2 was reacted with
O
O
MeI. Since hypervalent iodine compounds have proven to be
II 14
O
Ar
O
N
good 2-electron oxidants for Pd , the oxidation of 1 and 2 with
Pd
Pd
PhICl
2
was studied. Treatment of 1 with 1 equivalent of PhICl
2
in
to
O
O
PPh3
o
MeCN at 0 C afforded an orange species. Addition of NH
PF
4 6
3
IV
Ar = Ph (1), p-tolyl (2)
the reaction mixture led to isolation of a cationic Pd -LOEt
complex, [Pd(Ph)(PPh )(Cl)(LOEt)](PF (4), in 79% yield
Scheme 4). Similarly, the treatment of 2 with PhICl , followed by
afforded the cationic Pd p-tolyl complex
) (5).
3
6
)
(
2
2
3
Scheme 3. Syntheses of [Pd(Ar)(PPh )( -LOEt)] (Ar = Ph (1), p-tolyl (2)) and
IV
t
2
4 6
the addition of NH PF
[
Pd(ppyBu )( -LOEt)] (3).
3 6
[Pd(p-tolyl)(PPh )(Cl)(LOEt)](PF
(
PF6)
O
Recrystallization of 1 from CH
single crystals that were suitable for X-ray diffraction. The solid-
state structure of 1 is shown in Figure 1. The geometry around
Pd is pseudo square planar and the LOEt binds to Pd in an 
mode. A weak PdO interaction was found between Pd and the
uncoordinated P=O group [Pd(1)O(7) 2.783(2) Å cf. 2.133(2)
and 2.1259(19) Å for Pd(1)-O(8) and Pd(1)-O(9)]. Similar
2
Cl
2
/hexanes afforded yellow
O
O
O
O
Ar
, 0 o
C
2
i) PhICl
ii) NH PF , 25 oC
Pd
Pd
4
6
O
PPh3
-
2
Ph P
Cl
3
1
or 2
Ar
Ar = Ph (4), p-tolyl (5)
IV
3 6
Scheme 4. Synthesis of [Pd (Ar)(PPh )(Cl)(LOEt)](PF ) (Ar = Ph (4), p-tolyl (5)).
II
coordination geometry has been found for the reported Pd -LOEt
2
11a
2
complexes such as [Pd(Cl)(PPh
OEt)] . The Pd-C [1.968(3) Å] and Pd-P [2.203(7) Å] distances
in 1 are comparable with those in trans-[Pd(PPh (Ph)(I)] [2.029
3
)( -LOEt)] and [Pd(C
3
H
5
)( -
Complexes 4 and 5 are reasonably stable in solution at
11b
L
room temperature, but they undergo reductive elimination readily
at higher temperature (>40 C) (see later section). Unlike that in
1, the LOEt ligand in 4 is stereochemically rigid and three
NMR signals ( = 113.10, 118.55 and 127.98 ppm) were found
o
)
3 2
13
-
31
(
4) and av. 2.340 Å, respectively].
P
P
for the three inequivalent phosphorus nuclei. In addition, a
P
singlet at  = 45.94 ppm due to the PPh
3
ligand, which is more
P
downfield that that for 1 ( = 30.77 ppm), was observed.
As the Pd atom in 6-coordinated 4 is stereogenic, 4 was
isolated as a racemic mixture of two optical isomers. The crystal
structure of one of the optical isomers of 4 is depicted in Figure
2
. Selected bond lengths and angles are collected in Table 1.
-
The geometry around Pd is psuedo octahedral and the LOEt
ligand is in the more common  binding mode. The Pd-O(7)
3
bond [2.104(3) Å] is longer than that of Pd-O(8) bond [2.024(3)
Å], but shorter than that of Pd-O(9) bond [2.155(3) Å]. The
disparity of the Pd-O(LOEt) distances is indicative of the order of
-
-
the trans influence of the ligand Ph > PPh
3
> Cl . It may be
IV
noted that reported organo-Pd complexes usually contain two
or three -donating hydrocarbyl ligands; not many Pd mono-
IV
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
1
5
IV
organyl complexes have been isolated. Although cationic Pd
The treatment of 3 with PhICl
afforded [Pd ( -ppyBu )(Cl)(LOEt)](PF
reddish orange crystals in 80 % yield (Scheme 5).
2
and NH
4
PF
6
in MeCN at 0
2
o
IV
2
t
compounds are well documented, 4 is a rare example of a
mono-aryl complex characterized by X-ray
crystalllography, demonstrating the ability of LOEt to stabilize
C
6
) (6), isolated as
IV
cationic Pd
-
(PF )
6
IV
O
Pd .
O
O
O
Pd
N
O
N
i) PhICl , 0 oC
2
Pd
ii) NH PF C
, 0 o
4 6
O
Cl
6
IV
2
t
6
Scheme 5. Synthesis of [Pd ( -ppyBu )(Cl)(LOEt)](PF ) (6).
Contrary to 4 and 5, 6 is unstable in solution at room
temperature, as evidenced by NMR spectroscopy. When a
3
solution of 6 in CD CN was left to stand at room temperature for
3
1
P
ca. 1 h, the P NMR signals due to 6 ( = 112.0, 128.4 and
P
1
30.9 ppm) disapppeared and a new signal at  = 116.6 ppm
attributable to
II
a Pd species (vide infra) appeared. The
observation that 6 is less thermally stable than 4 or 5 is
unexpected because one would expect the rigid metallacyclic
IV
Figure 2. Molecular structure of one of the enantiomers of 4. The ellipsoids
structure would enhance the thermal stability of the Pd center
-
are drawn at 30% probability level. Hydrogen atoms and PF
clarity.
6
are omitted for
IV
in 6. It appears the rate of reductive elimination of the Pd
complexes is dependent on other factors (e.g. relative stability of
IV
the Pd phosphine and pyridine complexes) that are not well
understood. Additional experimental and computational studies
are required in order to elucidate the factors affecting the
Table 1. Selected bond lengths (Å) and angles (°) for 4, 6 and 7.
4
IV
Pd-O(7)
Pd-O(8)
Pd-O(9)
2.104(3)
2.024(3)
2.155(3)
175.10(9)
174.52(13)
89.46(9)
93.06(8)
88.63(12)
90.32(9)
92.98(13)
88.95(14)
Pd-Cl(1)
Pd-P(4)
Pd-C(31)
O(8)-Pd-Cl(1)
Cl(1)-Pd-P(4)
O(7)-Pd-O(9)
O(8)-Pd-O(7)
O(8)-Pd-C(31)
O(9)-Pd-P(4)
C(31)-Pd-P(4)
2.2804(11)
2.3097(11)
2.026(5)
178.46(9)
85.84(4)
86.70(12)
91.61(11)
88.15(16)
91.93(8)
reductive elimination of the Pd complexes.
o
Recrystallization of 6 from CH
2
Cl
2
/hexanes at -20
C
afforded orange single crystals. X-ray crystallography indicated
that the crystal was comprised of a racemic mixture of two
optical isomers of 6 containing a stereogenic Pd center. The
structure of one of the enantiomers of 6 featuring a chelating
O(7)-Pd-P(4)
C(31)-Pd-O(9)
O(7)-Pd-Cl(1)
O(8)-Pd-P(4)
O(8)-Pd-O(9)
O(9)-Pd-Cl(1)
C(31)-Pd-Cl(1)
C(31)-Pd-O(7)
t
ppyBu ligand is shown in Figure 3. Selected bond lengths and
IV
92.68(12)
angles are listed in Table 1. The geometry around Pd is
pseudo octahedral. The Pd-C [1.997(4) Å] and Pd-N [1.995(4) Å]
IV
distances compare well with those in reported Pd
6
14
Pd-O(7)
Pd-O(8)
Pd-O(9)
2.021(3)
2.011(3)
2.158(3)
176.44(9)
89.14(12)
89.60(9)
92.77(12)
91.79(12)
81.80(18)
89.48(13)
87.77(15)
Pd-Cl(1)
Pd-N(1)
Pd-C(41)
O(9)-Pd-Cl(1)
N(1)-Pd-Cl(1)
N(1)-Pd-O(7)
N(1)-Pd-O(8)
N(1)-Pd-O(9)
C(41)-Pd-O(8)
C(41)-Pd-O(9)
2.2606(12)
1.995(4)
1.997(4)
cyclometalated complexes. The Pd-O bond trans to C [2.158(3)
Å] is significantly longer than the other two Pd-O bonds [2.021(3)
and 2.011(3) Å] bonds, owing to the trans influence of the phenyl
ring.
O(7)-Pd-Cl(1)
O(7)-Pd-O(9)
O(8)-Pd-Cl(1)
O(8)-Pd-O(7)
O(8)-Pd-O(9)
N(1)-Pd-C(41)
C(41)-Pd-Cl(1)
C(41)-Pd-O(7)
93.44(9)
89.04(11)
88.33(14)
173.99(13)
94.13(14)
92.34(16)
174.96(16)
7
Pd-O(7)
Pd-O(8)
Pd-O(9)
2.014(4)
2.021(4)
2.167(5)
1.750(7)
175.31(12)
88.81(16)
88.10(13)
93.47(17)
91.61(17)
82.5(3)
Pd-Cl(1)
Pd-N(1)
Pd-C(41)
2.2622(17)
1.995(5)
1.984(7)
88.5(2)
95.56(13)
90.15(15)
87.92(19)
175.0(2)
93.2(2)
C(37)-Cl(2)
O(7)-Pd-Cl(1)
O(7)-Pd-O(9)
O(8)-Pd-Cl(1)
O(8)-Pd-O(7)
O(8)-Pd-O(9)
N(1)-Pd-C(41)
C(41)-Pd-Cl(1)
C(41)-Pd-O(7)
O(9)-Pd-Cl(1)
N(1)-Pd-Cl(1)
N(1)-Pd-O(7)
N(1)-Pd-O(8)
N(1)-Pd-O(9)
C(41)-Pd-O(8)
C(41)-Pd-O(9)
92.8(2)
175.0(2)
86.99(19)
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
Figure 3. Molecular structure of one of the enantiomers of 6. The ellipsoids
IV
heterocyclic-carbene alkoxide supported Pd
complex,
-
are drawn at 30% probability level. Hydrogen atoms and PF
clarity.
6
are omitted for
IV
[Pd L(bzq)Cl
2 2 2
] (L = OCMe CH (1-C{NCHCHNiPr}), bzq =
benzo[h]quinoline), underwent facile C(sp )-Cl reductive
2
II
8b
IV
elimination to give a Pd product.
Unlike 6, complex is stable in solution at room
temperature. No reductive elimination was found for 7 in CD CN
at room temperature for days, as evidenced by NMR
spectroscopy. The higher stability of 7 compared with the
unchlorinated analuge 6 is possibly owing to the stronger Pd-C
bond. The MALDI mass spectrum of 7 exhibited a peak at m/z
] . The structure of 7 (Figure 4)
is very similar to that of 6, except that the the meta hydrogen of
Reductive Elimination of Pd -LOEt Complexes
7
Although complexes 4 and 5 are reasonably stable in solution at
3
room temperature, they decomposed gradually in acetonitrile at
o
higher temperature (> 40 C), as evidenced by NMR
spectroscopy. When a CD
3
CN solution of 4 was warmed at 40
o
C
for 15 min,
a
new Pd-LOEt species, presumably
II
P
-
[
Pd (LOEt)(PPh
3
)(CD
3
CN)](PF ) (A), with  = 116.5 (LOEt ) and
6
+
922.0 that is assigned to [M - PF
6
2
6.16 (PPh ) ppm, was formed. In addition, GLC analysis
3
revealed that chlorobenzene was produced in 85% yield (with
t
the phenyl ring in the ppyBu ligand is replaced by a chlorine.
The Pd-C [1.984(7) Å] and Pd-N distances [1.995(5) Å] in 7 are
similar those in 6.
respect to 4). This result suggests that 4 underwent C-Cl
II
elimination to give a Pd species, A (Scheme 6). We have not
been able to crystallize A for further identification. On the other
hand, the reductive elimination of chloride anagloue of 4,
IV
[
(LOEt)Pd (Ph)(PPh
3
)(Cl)]Cl that was generated in-situ from the
led to isolation of the previously
reaction of 1 with PhICl
reported compound [Pd (LOEt)(PPh
characterized by NMR spectroscopy, along with chlorobezene
Scheme 6). Similarly, 5 underwent reductive elimination in
2
II
11a
3
)(Cl)]
that
was
(
o
CD
3
CN at 40 C to give 4-chlorotoluene and A.
Addition of NH Cl did not accelerate the reductive
4
elimination of 4, thus indicating that the C-Cl bond elimination
did not involve the nucleophilic attack of the phenyl ligand by
dissociated chloride. Therefore, it is reasonable to assume that
the the C-Cl elimination of 4 is an intramolecular process. A
2
similar intramolecular C(sp )-Cl bond formation has been
observed in the reductive elimination of a transient O,N,N-pincer
IV
3j
ligated Pd aryl chloride species previously.
X-
O
O
X-
O
O
4
0 o
C
Pd
O
NCMe
PPh
+
ArCl
2
t
Ph
3
P
Cl
CD
3
CN
Pd
-
6
Scheme 7. Synthesis of [Pd( -Cl-ppyBu )Cl(LOEt)](PF ) (7).
Ar
Ar = Ph, X = PF -
Ar = p-tol, X = PF -
O
-
3
or Cl-
6
X = PF
(A)
6
6
Cl-
=
IV
o
Scheme 6. Reductive elimination of Pd aryl chloride complexes at 40 C.
As mentioned earlier, 6 is not stable in solution at room
temperature. NMR spectroscopy indicated that at room
temperature in acetonitrile, 6 was gradually converted to a new
P
II
Pd-LOEt species ( = 116.6 ppm), possibly the Pd complex
t
[
Pd(Cl-ppyBu )(LOEt)(CD
3
CN)](PF
6
)
(B)
(Scheme
7).
Unfortunately, we have not been able to crystallize B from the
oily reaction mixture. However, the oxidation of as-prepared B
2
with PhICl afforded orange crystals that were identified as the
IV
t
Pd cyclometalated complex [Pd(Cl-ppyBu )Cl(LOEt)](PF
6
) (7)
t
[
ClppyBu H = 2-(4-tert-butyl-2-chlorophenyl)pyridine] containing
t
a chlorinated ppyBu ligand. Alternatively, 7 could be obtained in
5% yield from the reaction of 3 with excess PhICl (> 2
equivalents) in MeCN in the presence of NH PF . It should be
noted that the C(sp )-Cl elimination of [Pd (ppy) Cl ] to give
ortho-chlorinated phenylpyridine has been reported by Sanford
Figure 4. Molecular structure of one of the enantiomers of 7. The ellipsoids
7
2
-
6
are drawn at 30% probability level. Hydrogen atoms and PF are omitted for
4
IV
6
clarity.
2
2
2
14a
and co-workers previously.
Also, it was reported that a N- Conclusions
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
IV
In summary, we have synthesized the cationic Pd aryl
complexes [Pd(Ar)(PPh )(Cl)(LOEt)](PF ) (Ar = Ph (4), p-tolyl (5))
and [(LOEt)Pd(ppyBu )Cl](PF ) (6) by oxidation of the LOEtPd
precursors with PhICl . The {LOEtPd} moiety proved to be a good
1.15 (t, J = 7.2 Hz, 18H, CH
OCH ), 4.99 (s, 5H, Cp), 6.39 (m, 2H, H
tolyl), 7.21 (m, 6H, PPh ), 7.32 (m, 3H, PPh
3
, LOEt), 2.06 (s, 3H, CH
of tolyl), 6.85 (m, 2H, H
), 7.48 (m, 6H, PPh ) ppm.
, 25 C):  = 108.26 (s, LOEt), 30.99 (s,
3
), 3.85-3.95 (m, 12H,
2
o
m
of
3
6
t
II
3
3
3
6
31
1
o
P { H} NMR (162 MHz, CDCl
PPh ) ppm. Elemental analysis calcd (%) for C42
C 50.69, H 5.77; found: C 51.72, H 5.60.
3
2
3
9 4
H57CoO P Pd (994.13):
IV
platform for the study of reductive elimination of Pd aryl
complexes. 4 and 5 underwent C-Cl reductive elimination at 40
C to give chloroarenes. On the other hand, the reductive
elimination of 6 at room temperature gave a Pd species that
Cl-ppyBu )Cl(LOEt)](PF
7). Complexes 4, 6 and 7 are rare examples of structurally
characterized cationic Pd mono-aryl complexes, demonstrating
the ability of LOEt ligand to stabilize high oxidation state Pd
complexes. The study of LOEt-supported high-valent group 10
and 11 transition-metal (e.g. Ni, Cu) complexes that can find
applications in C-H activation is underway.
o
t
2
t
[
Pd(ppyBu )( -LOEt)] (3): To a solution of [Pd(ppyBu )Cl]
2
(100 mg,
II
0
2 2
.142 mmol) in CH Cl (5 mL) was added [AgLOEt] (46 mg, 0.072 mmol).
2
t
further reacted with PhICl
2
to yield [Pd(
-
6
)
The reaction mixture was stirred at room temperature overnight. The
AgCl formed was filtered off and the solvent was pumped off.
Recrystallization from hexanes at -18 °C afforded yellow crystals. Yield:
(
IV
1
o
-
3
44 mg (73%). H NMR (400 MHz, CDCl , 25 C):  = 1.28 (t, J = 7.2 Hz,
1
4
8H, CH
.29 (m, 6H, OCH
3
, LOEt), 1.30 (s, 9H, C(CH
), 5.10 (s, 5H, Cp), 7.00 (dd, J = 6.2 Hz, 1H, H ), 7.07
), 7.23 (s, 1H, H ), 7.38 (d, J = 8.0 Hz, 1H, H ), 7.50
3 3 2
) ), 4.13-4.19 (m, 6H, OCH ), 4.24-
4
2
(
d, J = 8.0 Hz, 1H, H
p
3
o
m
5
(
d, J = 7.6 Hz, 1H, H ), 7.71 (dd, J = 6.2 Hz, 1H, H ), 8.54 (d, J = 4.8 Hz,
6
31
1
o
1
H, H ) ppm. P { H} NMR (162 MHz, CDCl
51CoNO
.03, N 1.64; found: C 46.31, H 6.17, N 1.79.
3
, 25 C):  = 110.8 (s) ppm.
Elemental analysis calcd (%) for C32
6
H
9 3
P Pd (851.11): C 45.11, H
Experimental Section
[
Pd(Ph)(PPh
3
)(Cl)(LOEt)](PF
(28 mg, 0.10 mmol) in MeCN was stirred at 0 C for 5 min, the
PF
16.3 mg, 0.10 mmol) was added and the mixture was stirred at room
temperature for 10 min. The orange solution was vacuum dried, washed
with hexanes and then extracted with CH Cl . Recrystallization from
/hexanes at -20 C afforded orange crystals which were suitable
6
) (4): A solution of 1 (100 mg, 0.10 mmol)
General: All manipulations were carried out under dinitrogen by standard
Schlenk techniques. Solvents were purified by standard procedures and
distilled prior to use. NMR spectra were recorded on a Bruker ARX 400
o
and PhICl
2
reaction mixture changed from yellow to orange immediately. NH
(
4
6
1
31
spectrometer operating at 400, 376.5, and 162 MHz for H and P,
respectively. Chemical shifts (, ppm) were reported with reference to
1
31
4 3 4
SiMe ( H) and H PO ( P), respectively. Reductive elimination products
2
2
o
CH
2 2
Cl
were determined by a HP6850 Chromatograph equipped with a FID
detector. Elemental analyses were performed by Medac Ltd., Surrey, UK.
Mass spectrum was recorded on a Waters Mass Spectrometer, with
1
for X-ray diffraction study. Yield: 92 mg (79 %). H NMR (400 MHz,
CDCl
3
CH
(
(
o
3
, 25 C):  = 0.89 (t, J = 7.2 Hz, 6H, CH
H, CH , LOEt), 1.33 (t, J = 7.2 Hz, 6H, CH , LOEt), 1.38 (t, J = 7.2 Hz, 3H,
, LOEt), 3.04-3.10 (m, 1H, OCH ), 3.29-3.62 (m, 4H, OCH ), 3.69-3.75
), 3.93-4.08 (m, 2H, OCH ), 4.14-4.26 (m, 4H, OCH ), 5.07
of Ph), 7.13 (dd, J = 7.6 Hz, 2H, H
3
, LOEt), 0.97 (t, J = 7.2 Hz,
1
6
17
MALDI Micro MX module. The compounds PhICl
2
2
,
AgLOEt
,
trans-
were
3
3
13
t
18
2
[Pd(PPh
3
)
2
(Ar)(I)] (Ar
=
Ph, p-tolyl) and [Pd( -ppyBu )Cl]
3
2
2
m, 1H, OCH
s, 5H, Cp), 6.91 (br, 3H, H
2
2
2
prepared according to literature methods. All other reagents were
purchased from standard commercial sources and used without further
p
and H
o
m
31
1
t
t
of Ph), 7.39-7.41 (m, 12H, PPh
3 3
), 7.66-7.69 (m, 3H, PPh ). P { H} NMR
purifications. Atom labeling schemes for the ppyBu and Cl-ppyBu
o
(162 MHz, CDCl
3
, 25 C):  = 113.10 (m, LOEt), 118.55 (m, LOEt), 127.98
), -144.48 (sept, J = 712 Hz, PF ) ppm.
Pd (1160.05): C
ligands are shown in Scheme 8.
(
m, LOEt), 45.94 (s, PPh
3
6
Elemental analysis calcd (%) for C41
6 9 5
H55ClCoF O P
X
42.40, H 4.77; found: C 42.17, H 4.40.
4
3
m
p
5
[
Pd(p-tolyl)(PPh
3
)(Cl)(LOEt)](PF
6
) (5): A solution of 2 (100 mg, 0.10
o
N
mmol) and PhICl
2
(28 mg, 0.10 mmol) in MeCN was stirred at 0 C for 5
6
o
Pd
min, during which the color of the mixture changed from yellow to orange.
NH PF (16.3 mg, 0.10 mmol) was added and the mixture was stirred at
room temperature for 10 min. The solvent was pumped off, and the
residue was washed with hexanes and then extracted with CH Cl
X = H (ppyBut)
Cl (Cl-ppyBut)
4
6
=
t
t
Scheme 8. Atom labelling scheme for the ppyBu and Cl-ppyBu ligands.
2
2
.
o
Recrystallization from CH
Yield: 87 mg (72 %). H NMR (400 MHz, CDCl
2
Cl
2
/hexanes at -20 C afforded orange crystals.
1
o
3
, 25 C):  = 0.83 (t, J =
2
[
(
Pd(Ph)(PPh
3
)( -LOEt)] (1): To a solution of trans-[Pd(PPh
3
)
2
(Ph)(I)]
7
.2 Hz, 3H, CH
3
, LOEt), 0.86 (t, J = 7.2 Hz, 3H, CH
3
, LOEt), 0.92 (t, J = 7.2
, LOEt), 1.28 (t, J = 7.2 Hz,
), 3.20-3.52 (m,
), 3.84-4.01 (m, 2H, OCH ), 4.10-
), 5.01 (s, 5H, Cp), 6.89-6.91 (m, 4H, H and H of
), 7.60-7.62 (m, 3H, PPh ) ppm. P { H}
, 25 C):  = 112.60 (m, LOEt), 118.05 (m, LOEt),
26.95 (m, LOEt), 45.64 (s, PPh ), -144.5 (sept, J = 712 Hz, PF ) ppm.
Elemental analysis calcd (%) for C42 57ClCoF Pd (1174.07): C
2.91, H 4.89; found: C 42.47, H 4.92.
100 mg, 0.12 mmol) in CH
2
Cl
2
(5 mL) was added [AgLOEt] (77 mg, 0.12
Hz, 3H, CH
, LOEt), 1.23 (t, J = 7.2 Hz, 6H, CH
3 3
mmol). The reaction mixture was stirred at room temperature overnight.
The grey solid (AgI) formed was filtered off and the solvent was pumped
off. Recrystallization from hexanes at -18°C afforded yellow crystals.
3
4
4
H, CH
H, OCH
.21 (m, 4H, OCH
3
, LOEt), 2.62 (s, 3H, CH
3 2
), 3.01-3.08 (m, 1H, OCH
2
), 3.60-3.66 (m, 1H, OCH
2
2
1
o
2
m
o
1
Yield: 98 mg (83%). H NMR (400 MHz, CDCl
.2 Hz, 18H, CH , LOEt), 3.84-3.96 (m, 12H, OCH
m, 2H, H of Ph), 6.61 (m, 1H, H of Ph), 7.02 (m, 2H, H
), 7.32 (m, 3H, PPh ), 7.51 (m, 6H, PPh ) ppm. P { H} NMR
, 25 C):  = 108.23 (s, LOEt), 30.77 (s, PPh ) ppm.
Elemental analysis calcd (%) for C41 55CoO Pd (980.12): C 50.19, H
3
, 25 C):  = 1.14 (t, J =
31
tolyl), 7.35-7.38 (m, 12H, PPh
NMR (162 MHz, CDCl
1
3
3
7
(
6
(
3
2
), 4.99 (s, 5H, Cp), 6.54
of Ph), 7.21 (m,
o
3
m
p
o
3
1
1
3
6
H, PPh
3
3
3
H
6 9 5
O P
o
162 MHz, CDCl
3
3
4
H
9 4
P
5
.65; found C 48.61, H 5.55.
2
t
[
Pd( -ppyBu )(Cl)(LOEt)](PF
and PhICl (33 mg, 0.12 mmol) in MeCN was stirred at 0 C for 5 min.
NH PF (19.5 mg, 0.12 mmol) was added and the orange mixture was
stirred for 10 min. The solvent was removed in vacuo, and the residue
was washed with hexanes and then extracted with CH Cl
6
) (6): A solution of 3 (100 mg, 0.12 mmol)
o
2
2
[
Pd(p-tolyl)(PPh
3
)( -LOEt)] (2): The compound was synthesized
4
6
3 2
similarly as for 1 using trans-[Pd(PPh ) (p-tolyl)(I)] in place of trans-
1
o
3 2 3
[Pd(PPh ) (Ph)(I)]. Yield: 78 %. H NMR (400 MHz, CDCl , 25 C):  =
2
2
.
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
o
Recrystallization from CH
2
Cl
Yield: 99 mg (80 %). H NMR (400 MHz, CDCl
.2 Hz, 3H, CH , LOEt), 1.03 (t, J = 7.2 Hz, 3H, CH
Hz, 6H, CH , LOEt), 1.40 (s, 9H, C(CH ), 1.44 (t, J = 7.2 Hz, 6H, CH
OEt), 3.35-3.44 (m, 1H, OCH ), 3.64-3.79 (m, 3H, OCH ), 4.11-4.19 (m,
H, OCH ), 4.28-4.46 (m, 7H, OCH ), 5.15 (s, 5H, Cp), 7.47 (d, J = 8.0
), 7.53 (dd, J = 6.0 Hz, 1H, H ), 7.56 (s, 1H, H
2
/hexanes at -20 C afforded orange crystals.
NMR spectroscopy. During the course of the reaction, the signals due to
1
o
3
, 25 C):  = 0.99 (t, J =
, LOEt), 1.37 (t, J = 7.2
[(LOEt)Pd(Ph)(PPh
known Pd complex [Pd(LOEt)(PPh
3
)(Cl)]Cl dropped while new signals attributable to the
)(Cl)] appeared. The reaction
II
7
3
3
3
3
3
)
3
3
,
completed in ca. 15 min, and then volatiles were removed in vacuo and
the residue was extracted with CH Cl /hexanes (1:1, v/v). Slow
evaporation of the solvent afforded yellow crystals that were identified as
L
1
2
2
2
2
2
2
4
11a
Hz, 1H, H
.0 Hz, 1H, H
p
o
), 7.71 (d, J =
), 8.00 (d, J = 8.0 Hz, 1H, H ), 8.21 (dd, J = 6.0 Hz, 1H,
3
the known compound [Pd(LOEt)(PPh )(Cl)] by NMR spectroscopy. Yield:
3
1
o
8
m
12 mg (85 %). H NMR (400 MHz, CDCl
18H, CH , LOEt), 3.85-3.93 (m, 6H, OCH ), 3.95-4.02 (m, 6H, OCH
(s, 5H, Cp), 7.36 (m, 6H, PPh ), 7.44 (m, 3H, PPh ), 7.78 (m, 6H, PPh
, 25 C):  = 111.22 (s, LOEt), 24.76
3
, 25 C):  = 1.20 (t, J = 7.2 Hz,
5
6
31
1
H ), 8.89 (d, J = 4.0 Hz, 1H, H ) ppm. P { H} NMR (162 MHz, CDCl
C):  = 112.0 (m, LOEt), 128.4 (m, LOEt), 130.9 (m, LOEt), -144.6 (sept, J =
3
, 25
3
2
2
), 4.99
o
3
3
3
)
31
1
o
7
C
12
Hz,
51ClCoF
PF
NO
6
)
ppm.
Elemental analysis
Pd (1031.05): C 37.23, H 4.98, N 1.36; found: C
calcd
(%) for
ppm. P { H} NMR (162 MHz, CDCl
(s, PPh ) ppm.
3
32
H
6
9
P
4
3
3
7.01, H 4.89, N 1.49.
X-ray Crystallography: Crystallographic data and refinement details for
1, 4, 6 and 7 are listed in Table 2. The diffraction intensity data of 1 was
2
t
[
6
Pd( -Cl-ppyBu )(Cl)(LOEt)](PF ) (7): 6 (100 mg, 0.098 mmol) was
dissolved in MeCN (10 mL) and solution was left to stand at room
collected with a Rigaku Gemini™ S X-ray Diffractometer with
o
temperature (25 C) for 1 h, during which color of the solution changed
monochromatized Cu-K radiation ( = 1.54178 Å) at 173 K. The
diffraction intensity data of 4 and 7 were collected with a Rigaku
SuperNova Atlas X-ray Diffractometer with monochromatized Mo-K
radiation ( = 0.71073 Å) at 100 K. The diffraction intensity data of 6 was
collected with a Rigaku SuperNova Atlas X-ray Diffractometer with
monochromatized Mo-K radiation ( = 0.71073 Å) at 173 K. Diffraction
data of 1, 4, 6 and 7 were collected and processed using the CrysAlisPro
software (Rigaku, 2012). Empirical absorption corrections were
performed using spherical harmonics, implemented in SCALE3
ABSPACK scaling algorithm in the CrysAlisPro software suite. Structure
solution and refinement for all complexes were performed using the
31
from orange to yellow. P NMR spectroscopy indicated that the yellow
II
P
solution contained a new Pd species ( = 116.6 ppm), tentatively
t
assigned as “[Pd(Cl-ppyBu )(LOEt)(CD
solution was added PhICl (27 mg, 0.098 mmol) and the mixture was
stirred at 0 C for 10 min. The solvent was removed in vacuo, and the
residue was washed with hexanes and then extracted with CH Cl
/hexanes at -20 C afforded orange single
3 6
CN)](PF )“ (B). To the yellow
2
o
2
2
.
o
Recrystallization from CH
crystals that were characterized as [Pd( -Cl-ppyBu )(Cl)(LOEt)](PF
Yield: 76 mg (73 %). Alternatively, 7 could be obtained in 75 % yield from
the reaction of 3 with excess PhICl (> 2 equiv.) in MeCN in the presence
2 2
Cl
2
t
6
) (7).
2
1
o
19
20
of NH
.01 (t, J = 7.2 Hz, 3H, CH
t, J = 7.2 Hz, 6H, CH , LOEt), 1.41 (s, 9H, C(CH
, LOEt), 3.38-3.48 (m, 1H, OCH ), 3.67-3.75 (m, 3H, OCH
.21 (m, 1H, OCH ), 4.28-4.48 (m, 7H, OCH ), 5.17 (s, 5H, Cp), 7.46 (s,
H, H ), 7.65 (s, 1H, H ), 7.73 (dd, J = 6.0 Hz, 1H, H ), 8.25 (dd, J = 6.0
4
PF
6
at room temperature. H NMR (400 MHz, CDCl
, LOEt), 1.04 (t, J = 7.2 Hz, 3H, CH
), 1.43 (t, J = 7.2 Hz,
), 4.10-
3
, 25 C):  =
Olex2 software package
(which embedded SHELXTL ). All the
1
(
6
4
1
3
3
, LOEt), 1.38
structures were solved by direct methods, expanded by difference
2
3
3
)
3
Fourier syntheses and refined by full matrix least-squares on F . All non-
H, CH
3
2
2
hydrogen atoms were refined anisotropically with a riding model for the
hydrogen atoms except noted separately. All the pictures of molecules
2
2
4
20
p
o
were made using XP implemented in SHELXTL. CCDC 1484763,
5
3
6
31
Hz, 1H, H ), 8.89 (d, J = 7.2 Hz, 1H, H ), 9.11 (d, J = 4.8 Hz, 1H, H ).
P
1484764, 1484765 and 1528378 contain the supplementary
crystallography data for complexes 1, 4, 6 and 7, respectively. These
data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif
1
o
{
H} NMR (162 MHz, CDCl
31.0 (m, LOEt), -144.5 (sept, J = 712 Hz, PF
3
, 25 C):  = 111.7 (m, LOEt), 128.3 (m, LOEt),
) ppm. MALDI-MS: m/z:
analysis calcd (%) for
Pd (1065.01): C 36.02, H 4.72, N 1.31; found: C
1
9
C
6
+
22.0
[M
CoF
-
PF
6
] .
Elemental
32
H
50Cl
2
6
NO
9
P
4
3
6.76, H 4.71, N 1.28.
Reductive elimination of 4 and 5 in CD
3
CN: The reductive eliminations
o
of 4 (0.01 mmol) and 5 (0.01 mmol) in CD
3
CN (0.5 mL) at 40 C were
1
31
1
monitored by H and P { H} NMR spectroscopy. During the course of
the reaction, the signals due to 4 and 5 dropped while a new signal
II
P
-
3
attributable to a Pd species, A ( = 116.5 (LOEt ), 26.16 (PPh ) ppm),
appeared. The signals of 4 and 5 disappeared in ca. 15 min. The yields
of chlorobenzene (85 %) and 4-chlorotoluene (83 %) were determined by
GLC analysis using bromobenzene as the internal standard.
1
o
Characterization data for A: H NMR (400 MHz, CD
t, J = 7.2 Hz, 18H, CH , LOEt), 4.04 (m, 12H, OCH
.52 (m, 6H, PPh ), 7.62 (m, 3H, PPh ), 7.74 (m, 6H, PPh
CN, 25 C):  = 116.55 (s, LOEt), 26.16 (s, PPh
3
CN, 25 C):  = 1.26
(
7
3
2
), 5.24 (s, 5H, Cp),
31
1
3
3
3
) ppm. P { H}
o
NMR (162 MHz, CD
ppm.
3
3
)
Reductive elimination of [(LOEt)Pd(Ph)(PPh
reductive elimination of [(LOEt)Pd(Ph)(PPh )(Cl)]Cl, which was generated
in-situ from the reaction of 1 (15 mg, 0.015 mmol) with PhICl (4.2 mg,
3 3
)(Cl)]Cl in CD CN: The
3
2
1
o
31
0
.015 mmol), in CD
3
CN (1 mL) at 40 C was monitored by H and
P
Table 2. Crystallographic data and experimental details for 1, 4, 6 and 7.
1
4
6
7
Formula
C
41
H
55CoO
9
P
4
Pd
C
41
H
55ClCoF
6
O
9 5
P Pd
C
32
H
51ClCoF
6
NO
9
P
4
Pd
C
32
H
2 6 9 4
50Cl CoF NO P Pd
F
w
981.06
1161.48
1032.40
1066.84
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
Crystal system
Space group
a [Å]
Triclinic
P-1
Monoclinic
P2 /c
12.7928(4)
16.4736(5)
22.3511(6)
90.00
94.034(3)
90.00
4698.7(2)
4
Monoclinic
P2 /c
19.5875(10)
11.4890(5)
20.9892(10)
90
114.452(6)
90
4299.8(4)
4
Monoclinic
P2 /c
19.4486(12)
11.4144(5)
21.4261(14)
90
113.872(8)
90
4349.6(5)
4
1
1
1
11.8720(6)
11.9815(5)
18.0435(9)
100.759(4)
96.812(4)
116.176(4)
2203.31(18)
2
b [Å]
c ([Å]
o



[ ]
[
o
o
[ ]
3
V [Å ]
Z
-1

calcd [g cm ]
1.479
173
1.642
100
1.595
173
1.629
100
T [K]
F(000)
1012
8.040
12963
2368
1.039
26931
2104
1.089
24810
2168
1.139
24571
-1

[mm ]
No. of reflns
No. of indep reflns
7712
8536
8332
8275
R
GoF
R
R
int
0.0347
1.003
0.0754
1.000
0.0492, 0.0805
0.0582
1.003
0.0655
1.001
0.0686, 0.1645
0.1139, 0.1891
a
b
c
2
1
, wR
, wR
(I > 2
(all data)
 – F

(I))
0.0340, 0.0816
0.0380, 0.0847
0.0559, 0.1195
0.0818, 0.1305
1
2
0.0825, 0.0888
a
2
1/2
b
c
2
2
2
2
2
1/2
GoF = [w(F
o
c
) /(Nobs – Nparam)] . R1 =F
o
– F
c
/F
o
. wR2 = [w(F
o
 – F
c
) wF
o
 ]
.
[
5]
a) A. R. Muci, S. L. Buchwald, Top. Curr. Chem. 2002, 219, 131-209; b)
D. A. Culkin, J. F. Hartwig, Acc. Chem. Res. 2003, 36, 234-245; c)
Palladium Reagents and Catalysts: New Perspectives for the 21st
Century (Ed: J. Tsuji), Wiley and Sons, New York, 2003; d) A. F. Littke,
G. C. Fu, Angew. Chem. Int. Ed. 2002, 41, 4176-4211; e) D. S. Surry, S.
L. Buchwald, Angew. Chem. Int. Ed. 2008, 47, 6338-6361; f) J. F.
Hartwig, Inorg. Chem. 2007, 46, 1936-1947.
Acknowledgements
The support from the Hong Kong Research Grants Council
project nos. 602913 and 16307216) and the Hong Kong
(
University of Science and Technology is gratefully
acknowledged.
[
6]
7]
D. Ciuparu, M. R. Lyubovsky, E. Altman, L. D. Pfefferle, A. Datye, Catal.
Rev. Sci. Eng. 2002, 44, 593-649.
[
a) J. Bruns, D. van Gerven, T. Klüner, M. S. Wickleder, Angew. Chem.
Int. Ed. 2016, 55, 8121-8124; b) P. L. Arnold, M. S. Sanford, S. M.
Pearson, J. Am. Chem. Soc. 2009, 131, 13912-13913; E. Abada, P. Y.
Zavalij, A. N. Vedernikov, J. Am. Chem. Soc. 2017, 139, 643-646.
a) A. Maleckis, M. S. Sanford, Organometallics 2011, 30, 6617-6627; b)
A. J. Canty, H. Jin, J. D. Penny, J. Organomet. Chem. 1999, 573, 30-35;
c) J. Cámpora, P. Palma, D. del Rio, E. Carmona, C. Graiff, A.
Tiripicchio, Organometallics 2003, 22, 3345-3347; d) J. Cámpora, P.
Palma, D. del Rio, J. A. Lopez, E. Alvarez, N. G. Connelly,
Organometallics 2005, 24, 3624-3628; e) A. J. Canty, H. Jin, A. S.
Roberts, B. W. Skelton, A. H. White, Organometallics 1996, 15, 5713-
5722; f) A. Milet, A. Dedieu, A. J. Canty, Organometallics 1997, 16,
5331-5341.
Keywords: tripodal oxygen ligand • palladium(IV) • aryl •
reductive elimination
IV
[1]
[2]
[3]
Reviews on Pd–catalyzed organic transformations that involve Pd
intermediates, see for example: a) P. Sehnal, R. J. K. Taylor, I. J. S.
Fairlamb, Chem. Rev. 2010, 110, 824-889; b) D. A. Petrone, J. Ye, M.
Lautens, Chem. Rev. 2016, 116, 8003-8104.
[8]
IV
Reviews on organometallic chemistry of Pd complexes, see for
example: a) L.-M. Xu, B.-J. Li, Z. Yang, Z.-J. Shi, Chem. Soc. Rev.
2
010, 39, 712-733; b) A. J. Hickman, M. S. Sanford, Nature 2012, 484,
1
77-185; c) K. Muñiz, Angew. Chem. Int. Ed. 2009, 48, 9412-9423.
IV
Reductive elimination of Pd complexes, see for example: a) J. M.
Racowski, M. S. Sanford, Top Organomet. Chem. 2011, 35, 61-84; b) A.
Vigalok, Acc. Chem. Res. 2015, 48, 238-247; c) I. M. Pendleton, M. H.
Pérez-Temprano, M. S. Sanford, P. M. Zimmerman, J. Am. Chem. Soc.
[9]
a) W. Kläui, Angew. Chem. Int. Ed. 1990, 29, 627-637. (b) W.-H. Leung,
b) Q.-F. Zhang, X.-Y. Yi, Coord. Chem. Rev. 2007, 251, 2266-2279.
[10] a) Y.-M. So, W.-H. Chiu, W.-M. Cheung, H.-Y. Ng, H. K. Lee, H. H.-Y.
Sung, I. D. Williams, W.-H Leung, Dalton Trans. 2015, 44, 5479-5487;
b) W.-H. Leung, E. Y.-Y. Chan, T. C.-Y. Lai, W.-T. Wong, Dalton Trans.
2000, 51-56; c) X.-Y. Yi, Y.-K. Sau, T. C.-H. Lam, I. D. Williams, W.-H.
Leung, Inorg. Chem. 2007, 46, 7193-7198; d) H.-F. Ip, Y.-M. So, H. K.
Lee, I. D. Williams, W.-H. Leung, Eur. J. Inorg. Chem. 2012, 3289-3295;
e) Y.-M. So, W.-H. Leung, Coord. Chem. Rev. 2016,
http://dx.doi.org/10.1016/j.ccr.2016.12.009.
2016, 138, 6049-6060; d) M. H. Pérez-Temprano, J. M. Racowski, J. W.
Kampf, M. S. Sanford, J. Am. Chem. Soc. 2014, 136, 4097-4100; e) N.
M. Camasso, M. H. Pérez-Temprano, M. S. Sanford, J. Am. Chem. Soc.
2014, 136, 12771-12775; f) M. D. Lotz, M. S. Remy, D. B. Lao, A.
Ariafard, B. F. Yates, A. J. Canty, J. M. Meyer, M. S. Sanford, J. Am.
Chem. Soc. 2014, 136, 8237-8242; g) X. Zhao, V. M. Dong, Angew.
Chem. Int. Ed. 2011, 50, 932-934; h) J. Hývl, J. Roithová, Org. Lett.
2
014, 16, 200-203. i) J. R. Brandt, E. Lee, G. B. Boursalian, T. Ritter,
[11] a) W. Kläui, M. Glaum, E. Hahn, T. Lügger, Eur. J. Inorg. Chem. 2000,
21-28; b) B. Domhiiver, H. Hamers, W. Kläui, M. Pfeffer, J. Organomet.
Chem. 1996, 522, 197-206.
Chem. Sci. 2014, 5, 169-179; j) L. A. Wright, E. G. Hope, G. A. Solan,
W. B. Cross, K. Singh, Dalton Trans. 2015, 44, 6040-6051.
[
4]
a) J. S. Topczewski, M. S. Sanford, Chem. Sci. 2015, 6, 70-76; b) Y. Ye,
N. D. Ball, J. W. Kampf, M. S. Sanford, J. Am. Chen. Soc. 2010, 132,
[12] W. Klaui, M. Glaum, T. Wagner, M. A. Bennett, J. Organomet. Chem.
1994, 472, 355-358.
1
4682-14687; c) C. F. Rosewall, P. A. Sibbald, D. V. Liskin, F. E.
[13] J. P. Flemming, M. C. Pilon, V. V. Grushin, Inorg. Chim. Acta 1998, 280,
87-98.
Michael, J. Am. Chem. Soc. 2009, 131, 9488-9489; d) A. J. Hickman, M.
S. Sanford, ACS Catal. 2011, 1, 170-174; e) J. M. Racowski, N. D. Ball,
M. S. Sanford, J. Am. Chem. Soc. 2011, 133, 18022-18025; f) L. T.
Pilarski, N. Selander, D. Bose, K. J. Szabo, Org. Lett. 2009, 11, 5518-
[14] a) S. R. Whitfield, M. S. Sanford, J. Am. Chem. Soc. 2007, 129, 15142-
15143; b) N. R. Deprez, M. S. Sanford, Inorg. Chem. 2007, 46, 1924-
1935; c) J. M. Racowski, N. D. Ball, M. S. Sanford, J. Am. Chem. Soc.
2011, 133, 18022-18025.
5521; g) N. Selander, B. Willy, K. J. Szabo, Angew. Chem. Int. Ed.
2
010, 49, 4051-4053; h) R. Alam, L. T. Pilarski, E. Pershagen, K. J.
[15] a) W. N. Oloo, P. Y. Zavalij, A. N. Vedernikov, Organometallics 2013,
32, 5601-5614; b) W. N. Oloo, P. Y. Zavalij, J. Zhang, E. Khaskin, A. N.
Vedernikov, J. Am. Chem. Soc. 2010, 132, 14400-14402; c) N. D. Ball,
Szabo, J. Am. Chem. Soc. 2012, 134, 8778-8781.
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
M. S. Sanford, J. Am. Chem. Soc. 2009, 131, 3796-3797; d) T. Furuya,
T. Ritter, J. Am. Chem. Soc. 2008, 130, 10060-10061; e) J. Vicente, A.
Arcas, F. Julia-Hernandez, D. Bautista, Chem. Commun. 2010, 46,
[18] E. C. Constable, T. A. Leese, D. A. Tocher, Inorg. Chim. Acta. 1991,
182, 93-100.
[19] O. V. Dolomanov, L. J. Bourhis, R. J. Gildea, J. A. K. Howard, H.
Puschmann, J. Appl. Cryst. 2009, 42, 339-341. OLEX2: A complete
structure solution, refinement and analysis program.
7
253-7255; f) J. Vicente, A. Arcas, F. Julia-Hernandez, D. Bautista,
Inorg. Chem. 2011, 50, 5339-5341.
[
[
16] X. F. Zhao, Z. Zhang, Synthesis 2007, 4, 551-557.
17] W. Kläui, Naturforsch. 1979, 34 B, 1403.
[20] G. M. Sheldrick, Acta Cryst. 2008, A64, 112-122.
This article is protected by copyright. All rights reserved.

European Journal of Inorganic Chemistry
10.1002/ejic.201700326
FULL PAPER
Entry for the Table of Contents (Please choose one layout)
Layout 2:
FULL PAPER
Organopalladium(IV) complexes*
Yat-Ming So, Ka-Chun Au-Yeung,
Herman H.-Y. Sung, Ian D. Williams,
and Wa-Hung Leung*
Page No. – Page No.
IV
5
Cationic Pd monoaryl complexes supported by the Kläui tripodal ligand [Co( -
Synthesis, Structure, and Reductive
Elimination of Cationic Palladium(IV)
Monoaryl Complexes Supported by a
Tripodal Oxygen Ligand
-
-
C
5
H
5
){P(O)(OEt)
has been studied.
2 3
} ] (LOEt ) have been synthesized and their reductive elimination
*one or two words that highlight the emphasis of the paper or the field of the study
This article is protected by copyright. All rights reserved.