Intermolecular Phenyl Ligand Transfer of Pt(II) and Pd(II) Complexes with Bidentate Ligand

Article abstract of DOI:10.1246/bcsj.77.139

[PtPh₂(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane) reacts with equimolar [PtCl₂(cod)] (cod = 1,5-cyclooctadiene) to give a mixture of [PtPh₂(cod)] (38%), [PtCl(Ph)(cod)] (53%) and [PtCl ₂(dppe)] (72%) via exchange of the phenyl and chloro ligands among the Pt complexes. The reaction is strongly inhibited by addition of Cl ^-. The intermolecular phenyl ligand transfer from Pd to Pt is observed in the reaction of [PdCl(Ph)(bpy)] (bpy = 2,2′-bipyridine) with [PtX₂(cod)] (X = Cl, I), which produces [PtX(Ph)(cod)]. The reaction of [PdCl(Ph)(bpy)] with [PdCl₂(cod)], giving [Pd₂(μ -Cl)₂ {(4,5-η-κC¹)-(C₈H ₁₂Ph)}₂], occurs much faster than a similar reaction of [PdCl(Ph)(bpy)] with [PtCl₂(cod)]. [PtPh₂(L₂)] (L₂ = cod, dppe) reacts with [PdCl₂(cod)] in CH ₂Cl₂ at room temperature to afford [Pd₂(μ -Cl)₂{(4,5-η-κC¹)-(C₈H ₁₂Ph)}₂] via intermolecular phenyl ligand transfer from Pt to Pd and subsequent insertion of a C=C bond of cod into the Pd-Ph bond. Cationic Pd complexes [Pd(acetone)₂(cod)]²⁺(BF ₄^-)₂ and [Pd(η³-C ₃H₅)(acetone)₂]+(BF₄^-) react with [PtPh₂(cod)] to form biphenyl. All these results indicate that chloro complexes of Pd and Pt with cod ligand undergo the ligand exchange with the phenyl complexes of these metals.

Full text of DOI:10.1246/bcsj.77.139

Ó 2004 The Chemical Society of Japan
Bull. Chem. Soc. Jpn., 77, 139–145 (2004)
139
Intermolecular Phenyl Ligand Transfer of Pt(II) and Pd(II)
Complexes with Bidentate Ligand
ꢀ
Yuji Suzaki and Kohtaro Osakada
Chemical Resources Laboratory, Tokyo Institute of Technology,
4259 Nagatsuta, Midori-ku, Yokohama 226-8503
Received July 17, 2003; E-mail: kosakada@res.titech.ac.jp
[PtPh2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane) reacts with equimolar [PtCl2(cod)] (cod = 1,5-cyclooc-
tadiene) to give a mixture of [PtPh2(cod)] (38%), [PtCl(Ph)(cod)] (53%) and [PtCl2(dppe)] (72%) via exchange of the
phenyl and chloro ligands among the Pt complexes. The reaction is strongly inhibited by addition of Clꢁ. The intermo-
lecular phenyl ligand transfer from Pd to Pt is observed in the reaction of [PdCl(Ph)(bpy)] (bpy = 2,20-bipyridine) with
[PtX2(cod)] (X = Cl, I), which produces [PtX(Ph)(cod)]. The reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)], giving
[Pd2(ꢀ-Cl)2{(4,5-ꢁ-ꢂC1)-(C8H12Ph)}2], occurs much faster than a similar reaction of [PdCl(Ph)(bpy)] with [PtCl2(cod)].
[PtPh2(L2)] (L2 = cod, dppe) reacts with [PdCl2(cod)] in CH2Cl2 at room temperature to afford [Pd2(ꢀ-Cl)2{(4,5-ꢁ-ꢂC1)-
(C8H12Ph)}2] via intermolecular phenyl ligand transfer from Pt to Pd and subsequent insertion of a C=C bond of cod into
the Pd–Ph bond. Cationic Pd complexes [Pd(acetone)2(cod)]2þ(BF4ꢁ)2 and [Pd(ꢁ3-C3H5)(acetone)2]þ(BF4ꢁ) react with
[PtPh2(cod)] to form biphenyl. All these results indicate that chloro complexes of Pd and Pt with cod ligand undergo the
ligand exchange with the phenyl complexes of these metals.
Intermolecular aryl ligand transfer of Pd(II) and Pt(II) com-
plexes was found in the 1970’s, although the reports on this
subject are still rare. Scheme 1 depicts conproportionation of
the diaryl and dihalogeno complexes of the metals and dispro-
portionation of the monoaryl halogeno complex. These aryl li-
gand transfer reactions would take place reversibly when the
stability values of the starting and resulting complexes are close
to each other. Conproportionation of [PtAr2(cod)] and [PtCl2-
(cod)] was reported by Eaborn to give [PtAr(Cl)(cod)].1 Addi-
tion of dppe to the reaction mixture formed three complexes:
[PtAr2(dppe)], [PtAr(Cl)(dppe)], and [PtCl2(dppe)]. An equi-
molar mixture of [Pt(C4H3S)2(cod)] (C4H3S = 2-thienyl) and
[PtCl2(cod)] was converted quantitatively to [PtCl(C4H3S)-
(dppe)], while the reaction of [Pt(C6H4Cl-3)2(cod)] with
[PtCl2(cod)], followed by addition of dppe, produced a mixture
of the diaryl, chloroaryl and dichloro platinum complexes in a
statistical ratio (1:2:1). [Pt(ꢂC-C5H5)2(CO)(PMe2Ph)] and
[PtCl2(CO)(PMe2Ph)] underwent conproportionation at room
temperature to give [Pt(ꢂC-C5H5)(Cl)(CO)(PMe2Ph)].2
[Pt(CH2COMe)2(cod)].4 The two produced complexes undergo
the conproportionation to regenerate the monophenyl platinum
complex. The halogeno(aryl)nickel and -palladium complexes
with bpy ligand liberated biaryl upon treatment with a polar sol-
vent such as DMF and with AgBF4.5 The reaction was proposed
to involve initial formation of cationic monoaryl complexes of
these metals, intermolecular aryl ligand transfer to give inter-
mediate diaryl complexes, and reductive elimination of the
product from the diaryl complexes. The organic ligand transfer
and subsequent reductive elimination of biaryl were utilized in
synthesis of macrocyclic compounds.6
The aryl ligand transfer also takes place between the com-
plexes with different metal centers or different auxiliary
ligands. Puddephatt found that [PtAr2(cod)] reacted with [PtI2-
(PMe2Ph)2] to give a mixture of [PtAr(I)(cod)] and [PtAr(I)-
(PMe2Ph)2] and that the reaction of [PtAr(Me)(cod)] with
[PtI2(PMe2Ph)2] afforded [PtMe(I)(PMe2Ph)2] via the selective
methyl ligand transfer between the two Pt complexes.7 The re-
actions of [cis-PdCl2(PMe2Ph)2] with [PtMe(C6H4Me-4)(cod)]
and with [PtMe(C6H4Me-4)(PMe2Ph)2] produced different
products. The Pt–cod complex underwent aryl ligand transfer
from Pt to Pd, while the Pt–PMe2Ph complex reacted with
[cis-PdCl2(PMe2Ph)2] to exchange the Cl and Me ligands, as
shown in Scheme 2.
Thermally induced disproportionation of [PtPh(O2CCF3)-
(dmpe)] (dmpe = 1,2-bis(dimethylphosphino)ethane) formed
an equimolar mixture of [PtPh2(dmpe)] and [Pt(O2CCF3)2-
(dmpe)].3 Recently we observed disproportionation of [Pt(Ph)-
(CH2COMe)(cod)] to give a mixture of [PtPh2(cod)] and
In this paper, we report phenyl ligand transfer among the
Pd(II) and Pt(II) complexes with bidentate ligands such as
cod, bpy, and dppe. The chelating ligands fix cis structure of
the square-planar complexes, which make the pathway of the
intermolecular ligand transfer simpler than those of the com-
plexes with monodentate auxiliary ligands. The reactions of
Pd and Pt complexes with aryl and halogeno ligands in this
study demonstrate smooth aryl ligand transfer between these
group 10 metals.
Ar
Ar
X
X
Ar
X
Conproportionation
Disproportionation
M
+
M
2
M
X = anionic ligand
M = Pd(II), Pt(II)
Scheme 1.
Published on the web January 13, 2004; DOI 10.1246/bcsj.77.139

140 Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
Ph Ligand Transfer of Pd and Pt
Me
Me
Cl
(cod)Pt
+
(PhMe2P)2Pd
L2 = cod
Cl
Me
Cl
not characterized
PhMe2P
Pd
PhMe2P
+
(L2)Pt
Me
Cl
Me
cis
Cl
PhMe2P
PhMe2P
Me
L2 = 2 PMe2Ph
L2 = cod, 2 PMe2Ph
Pt
+
Pd
Cl
PMe2Ph
PMe2Ph
Scheme 2.
[PtCl(Ph)(cod)] and [PtCl2(dppe)] during the reaction. The re-
actions of [PtPh2(cod)] and of [PtPh2(dppe)] with [PtCl2(dppe)]
were conducted but did not cause the ligand exchange.
An equimolar mixture of [PtPh2(cod)] and [PtCl2(cod)] in
CH2Cl2 is converted into [PtCl(Ph)(cod)] (72% by NMR based
on [PtPh2(cod)] + [PtCl2(cod)], 3 h; 93%, 24 h) at room tem-
perature (Eq. 2).
Results and Discussion
Phenyl Ligand Transfer between Pt Complexes. An
equimolar reaction of [PtPh2(dppe)] with [PtCl2(cod)] causes
the phenyl ligand transfer to give a mixture of the platinum
complexes as shown in Eq. 1.
Ph
Ph
Cl
Cl
P
Ph
Ph
X
X
Ph
Ph
Ph
X
Pt
+
Pt
CH2Cl2
r. t.
Pt
+
Pt
2
Pt
P
CH2Cl2
r. t.
ð2Þ
Ph
+
Ph
ð1Þ
Ph
Ph
Ph
X = Cl, I
Ph
Ph
Ph
P
Cl
Cl
+
Pt
Pt
Pt
The reactions of [PtPh2(cod)] with [PtX2(cod)] (X = Cl, I) in
2:1 molar ratio form [PtX(Ph)(cod)] quantitatively. Eaborn pre-
viously reported that the reaction of [Pt(C6H4Cl-3)2(cod)] with
[PtCl2(cod)] and subsequent addition of dppe gave a mixture of
[Pt(C6H4Cl-3)2(dppe)], [PtCl(C6H4Cl-3)(dppe)] and [PtCl2-
(dppe)].1 By comparison of their results with ours, the forma-
tion of three Pt–dppe complexes in their reports is ascribed to
initial conproportionation of the two complexes, giving a mix-
ture of three Pt–cod complexes followed by replacement of cod
ligand with dppe.
The reaction of [PtPh2(cod)] with the Pt–cod complexes was
conducted with additives in order to obtain further insights into
the mechanism. Table 1 summarizes the results. Addition of
Et4NCl or KCl inhibits the phenyl ligand transfer from
[PtPh2(cod)] to [PtCl2(cod)] (runs 3, 4), indicating that the re-
action is initiated by dissociation of the Cl ligand. Addition of
P
Ph
Cl
38% (NMR)
53% (NMR)
72% (isolated)
The 1H and 31P{1H} NMR spectrum of the products contain the
signals of [PtPh2(cod)] (38% by NMR based on [PtCl2(cod)]),
[PtCl(Ph)(cod)] (53%), unreacted [PtCl2(cod)] (12%), and Pt–
dppe complexes. The 31P{1H} NMR spectrum shows the pres-
ence of [PtCl2(dppe)] and [PtPh2(dppe)] in approximately 3:1
molar ratio, but does not exhibit the peaks due to [PtCl-
(Ph)(dppe)]. [PtCl2(dppe)] was isolated in 72% (based on
[PtPh2(dppe)]) from column chromatography (SiO2) of the
products. [PtCl(Ph)(dppe)], which should be formed initially
in the reaction of [PtPh2(dppe)] with [PtCl2(cod)], is not con-
tained in the products. The complex probably undergoes the
disproportionation to give a mixture of [PtCl2(dppe)] and
[PtPh2(dppe)] or reacts further with [PtCl2(cod)] to form
Table 1. Results of Reactions of [PtPh2(cod)] with Pt–cod Complexesa)
Run
Complex
[PtCl2(cod)]
Additive
none
Time
3 h
PtCl(Ph)(cod)b)
1
2
3
4
5
6
7
8
9
10
72%
93%
0%
none
Et4NCl (0.5 mmol)
KCl (0.5 mmol)c)
COD (0.1 mmol)
COD (0.5 mmol)
COD (1 mmol)
none
24 h
3 h
3 h
3 h
3 h
3 h
3 h
24 h
3 h
0%
57%
51%
57%
36%
75%
94%
[PtI2(cod)]
none
none
ꢁ
d)
[Pt(acetone)2(cod)]2þ(BF4
)
2
a) Conditions: [PtPh2(cod)] (0.10 mmol) and Pt–cod complex (0.10 mmol), solvent: CH2Cl2
(runs 1–9) and acetone (run 10), room temperature. b) Yields were based on sum of the start-
ing platinum complexes (0.20 mmol). c) 18-crown-6 ether (0.5 mmol) and water (0.1 cm3)
ꢁ
were added. d) [Pt(acetone)2(cod)]2þ(BF4
) was generated in situ from AgBF4 and
2
[PtCl2(cod)] in acetone. KCl was added after the reaction.

Y. Suzaki et al.
Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
141
cod ligand lowers yield of [PtCl(Ph)(cod)] in the reaction (runs
5, 6), although decrease of the yield by cod addition is much
smaller than that would be expected from the mechanism of
the reaction triggered by cod dissociation. The reaction of
[PtI2(cod)] and [PtPh2(cod)] forms [Pt(I)Ph(cod)] in a lower
yield than of [Pt(Cl)Ph(cod)] formed from [PtCl2(cod)] and
[PtPh2(cod)]. The result is attributed to the dissociation of Cl
ligand to form the cationic intermediate being more facile than
dissociation of I ligand. Cationic Pt complex with cod,
[Pt(acetone)2(cod)]2þ(BF4ꢁ)2, reacts with [PtPh2(cod)] easily,
and the reaction for 3 h followed by addition of KCl produces
[PtCl(Ph)(cod)] in 94%.
Phenyl Ligand Transfer of Monophenyl Palladium Com-
plexes with Pt and Pd Complexes. Diphenylpalladium com-
plexes with chelating ligands such as cod and dppe decompose
easily via intramolecular reductive elimination of biphenyl, and
are not suited for the study of the phenyl ligand transfer reac-
tions. Chloro(phenyl)palladium complexes, which do not cause
the reductive elimination, are employed in the following study.
The reaction of [PdCl(Ph)(bpy)] with [PtCl2(cod)] in CH2Cl2
causes transfer of the phenyl ligand from Pd to Pt to afford
[PtCl(Ph)(cod)] (66% after 5 days) (Eq. 3).
L
L
Cl
Cl
Ph
Ph
Pd
+
Pt
2
CH2Cl2, r. t.
(L^L = cod, dppe)
Ph
Ph
ð5Þ
L
Cl
Cl
Cl
Pd
Pd
+
Pt
L
Cl
1
76%
76%
94 % (L^L = cod, 12 h)
(L^L = dppe, 20 h)
1 was isolated in 66% yield from a preparative scale reaction of
[PtPh2(cod)] with [PdCl2(cod)] (Pt:Pd = 1:2). A similar reac-
tion of [PtPh2(dppe)] with [PdCl2(cod)] forms 1 (76%) and
[PtCl2(dppe)]. The reaction mixture also contains remaining
[PdCl2(cod)] (11%). An equimolar reaction of [PtCl(Ph)(cod)]
with [PdCl2(cod)] in a dilute CH2Cl2 solution ([Pt] = [Pd] =
0.020 M) converts the complexes into a mixture of 1 and
[PtCl2(cod)] quantitatively. Complex 1 is formed via formation
of intermediate [PdCl(Ph)(cod)] and insertion of a C=C bond
of cod into the Pd–Ph bond. Reaction of [PtPh2(bpy)] with
[PdCl2(cod)] forms 1 in 6% yield after 20 h via the phenyl li-
gand transfer. No phenyl ligand transfer is observed in the re-
actions of [PtPh2(cod)] with [PdCl2(dppe)] and [PdCl2(bpy)]
and of [PtPh2(dppe)] with [PdCl2(dppe)].
As mentioned before, [PtPh2(cod)] reacts with cationic Pt
complex, [Pt(acetone)2(cod)]2þ(BF4ꢁ)2, to cause the phenyl li-
gand transfer between Pt. An analogous reaction with cationic
Pd complexes was examined in order to compare the reactivity
of Pt and Pd complexes. [PtPh2(cod)] reacts with [Pd-
(acetone)2(cod)]2þ(BF4ꢁ)2, prepared in situ from AgBF4 and
[PdCl2(cod)] in acetone, and produces biphenyl, 1, and [PtCl2-
(cod)] after treatment of the reaction mixture with NaCl as
shown in Eq. 6.
N
N
Cl
Cl
Ph
Cl
Ph
Cl
Pt
+
Pd
Pt
ð3Þ
CH2Cl2
r. t.
66%
The starting [PtCl2(cod)] remains in the reaction mixture
(33%). Pd complexes formed by the reaction are not character-
ized by the NMR spectroscopy due to their low solubility. The
reaction of [PdI(Ph)(bpy)] with [PtCl2(cod)] in a 10:1 molar ra-
tio leads to formation of [PtI(Ph)(cod)] in 96% yield. The reac-
tion of [PdI(Ph)(bpy)] with [PtI2(cod)] (5:1) requires heating at
50 ꢂC and produces [PtI(Ph)(cod)] in 69% after 3 days.
An equimolar reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)]
at room temperature for 24 h forms the dipalladium complex,
[Pd2(ꢀ-Cl)2{(4,5-ꢁ-ꢂC1)-(C8H12Ph)}2] (1) in 78% yield
(Eq. 4).
2+
1) r. t., 1 h
2) NaCl
acetone
acetone
Ph
Ph
-
Pd
2
(BF4
)
Pt
+
2
Ph
Pd
Ph
ð6Þ
Cl
Cl
Cl
Pd
+
+
Ph Ph
Pt
Cl
Ph
Pd
Ph
Pd
1
N
N
Cl
Cl
Cl
Ph
Cl
Pd
+
Pd
2
2
ð4Þ
The 1H NMR spectrum of the reaction mixture indicates the ab-
sence of [PtPh2(cod)] and [PtCl(Ph)(cod)]. The phenyl ligand
transfer from Pt to Pd is rapid and is completed in 1 h. The re-
action involves an intermediate cationic phenyl palladium com-
plex [Pd(Ph)(acetone)(cod)]þ(BF4ꢁ) formed via phenyl ligand
transfer from [PtPh2(cod)] to [Pd(acetone)2(cod)]2þ(BF4ꢁ)2.
This cationic intermediate undergoes disproportionation to give
[PdPh2(cod)] that undergoes facile reductive elimination of bi-
phenyl similarly to the reaction of AgBF4 with [PdI(Ph)(b-
py)].5b Insertion of a C=C bond of the intermediate and coor-
dination of Cl ligand leads to complex 1, similarly to the reac-
tion of [PtPh2(cod)] with [PtCl2(cod)].
CH2Cl2
r. t., 24 h
Cl
1
Complex 1 was already prepared from the reaction of
[PdCl2(cod)] with Ph4Sn or PhMgBr.8 The above reaction in-
volves formation of an intermediate [PdCl(Ph)(cod)] via phenyl
ligand transfer between the two palladium complexes and in-
sertion of a C=C double bond of the cod ligand into the Pd–
Ph bond. Reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)] in a
2:1 molar ratio gives 1 in 96% yield after 24 h.
Phenyl Ligand Transfer from Diphenylplatinum Com-
plexes to Pd Complexes. The reaction of [PtPh2(cod)] with
[PdCl2(cod)] in a 1:2 molar ratio produces 1 (76% NMR yield)
and [PtCl2(cod)] (94%) as shown in Eq. 5.
Cationic
ꢃ-allylpalladium
complex
[Pd(ꢁ3-C3H5)-
(acetone)2]þ(BF4ꢁ), generated by addition of AgBF4 to an ace-
tone solution of [PdCl(ꢁ3-C3H5)]2, reacts with [PtPh2(cod)] to

142 Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
Ph Ligand Transfer of Pd and Pt
+
plexes of these metals caused the smooth intermolecular aryl
ligand transfer.5,6 Transition metal complexes containing aryl
ligand bridging to the two metal centers were isolated and char-
acterized.10
Cl
M
Cl
Cl
Cl-
M
solv.
+
Table 2 summarizes the results of the exchange of the phenyl
and chloro ligands of the neutral Pd and Pt complexes. Trans-
metalation of the phenyl ligand proceeds only when the chloro
complexes have a cod ligand. Cod bonded to dichloro com-
plexes of Pd and Pt seems to play dual roles to enhance the
phenyl ligand transfer. The relatively large trans effect of cod
promotes dissociation of Cl ligand to give a cationic intermedi-
ate [MCl(solvent)(cod)]þ(Clꢁ). The electron-accepting charac-
ter of the cod ligand increases the reactivity of the metal center
of the cationic intermediate toward formation of the dinuclear
intermediate. Table 3 summarizes the 13C{1H} NMR data of
cis-dimethylplatinum complexes.11–14 Positive chemical shift
of CH3 carbons of [PtMe2(cod)] and [PtMe2(nbd)] (nbd =
2,5-norbornadiene) suggests low electron density of the carbon
and less basic nature of the olefin ligand than the diamine
whose Pt complexes exhibit the CH3 carbon signals at negative
regions. Thus the cod ligand serves as a ꢃ-accepting ligand to
make the metal center more electrophilic than dppe or bpy and
to enhance ligand exchange.
+
L
L
L
L
Cl
Ph
Ph
+
M
M'
Cl-
Cl-
M
M'
ClPh
Ph
solv.
+
L
L
L
L
Ph
Cl
M
M'
Cl-
M
M'
+
ClPh
Cl
Scheme 3.
give biphenyl (95% based on the initial amount of [PtPh2-
(cod)]) after 46 h. No allylbenzene was formed, suggesting that
the reaction does not involve an allyl(phenyl)palladium inter-
mediate that may be expected as a product of the phen-
yl ligand transfer from [PtPh2(cod)] to [Pd(ꢁ3-C3H5)-
(acetone)2]þ(BF4ꢁ). The reaction of [PtPh2(cod)] with
[PdCl(ꢁ3-C3H5)]2 occurs slowly to give a mixture of biphenyl
(26%) and [PtCl(Ph)(cod)] (40%) even after 12 days.
Reaction Mechanism of Phenyl Ligand Transfer of the
Neutral Complexes. Scheme 3 depicts the plausible mecha-
nism of the aryl ligand transfer of the neutral diphenyl and di-
chloro complexes with cod ligand. Dissociation of Cl ligand
from the dichloro complex gives an intermediate cationic com-
plex, [MCl(solvent)(cod)]þ(Clꢁ). The formed cationic com-
plex and the diphenyl complex produce a dinuclear intermedi-
ate with a bridging phenyl ligand. Our previous studies on the
chemical properties of halogeno(aryl)nickel and -palladium
complexes with bpy ligand revealed that the cationic com-
Summary
This study revealed that exchange of the phenyl and chloro
ligands takes place among the Pd and Pt complexes by choos-
ing the cod as the ligand of the chloro complexes. The reaction
between the Pt complexes proceeds via cationic intermediate
formed by dissociation of Cl ligand. The phenyl ligand transfer
from Ph–Pt complexes to [PdCl2(cod)] is followed by the inser-
tion of a C=C bond of cod into Pd–Ph.
Table 2. Results of the Phenyl Ligand Transfera)
Phenyl complexes
[PtPh2(cod)]
[PtPh2(dppe)]
[PtPh2(bpy)]
b)
[PdCl(Ph)(bpy)]
yes
[PtCl2(cod)]
[PtCl2(dppe)]
[PdCl2(cod)]
[PdCl2(dppe)]
[PtCl2(bpy)]
yes
no
yes
no
yes
no
—
—
b)
b)
—
yes
yes
no
yes
b)
b)
—
—
—
—
b)
b)
b)
no
—
a) Reaction conditions: [chloro complex]:[phenyl complex] = 1:1–1:5, r.t.–50 ꢂC, 3 h–5 d,
See Experimental Section for details. yes: products of the phenyl ligand transfer are ob-
served in the NMR (1H and 31P{1H}) spectra. no: products were not observed in the
NMR spectra. b) Not applied.
Table 3. 13C{1H} NMR Data of [cis-PtMe2(ligand)]
Liganda)
cod
4.7
nbd
dppe
1.0
2-py
RN=CH–CH=NR
tmeda
Chemical shift of
CH3 ligand (ppm)
4.56
ꢁ8:18
ꢁ11:6 (R = c-C5H11)
ꢁ14:2 (R = C6H4Me-4)
ꢁ15:2 (R = C6H3Me2-2,6)
799.0 (R = c-C5H11)
793.5 (R = C6H4Me-4)
785.5 (R = C6H3Me2-2,6)
14
ꢁ23:67
1J(195Pt–13C) (Hz) 773 ꢃ 2 814.5
610
13
688.5
826.2
12
Reference
11
12
12
a) nbd = 2,5-norbornadiene, py = pyridine, tmeda = N,N,N0,N0-tetramethylethylenediamine.

Y. Suzaki et al.
Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
143
ing complexes were not observed in the reaction mixture after 3 h.
Reaction of [PtPh2(cod)] and [PtCl2(cod)] in the Presence of
Added cod. CH2Cl2 (2.0 cm3) solutions of mixture of [PtPh2-
(cod)] (0.10 mmol), [PtCl2(cod)] (0.10 mmol), and cod (0.1, 0.5,
1 mmol) were stirred for 3 h at room temperature. Evaporation
of the solvent gave the products as a white solid. Table 1 summa-
rized the results.
Reaction of [PtPh2(cod)] with [Pt(acetone)2(cod)]2þ(BF4ꢀ)2.
To an acetone (0.5 cm3) solution of [PtCl2(cod)] (37.4 mg, 0.10
mmol) was added an acetone (1.5 cm3) solution of AgBF4 (40.4
mg, 0.21 mmol). After the mixture was stirred for ca. 15 min at
room temperature, the resulting AgCl was remove by filtration. Af-
ter addition of [PtPh2(cod)] (45.7 mg, 0.10 mmol) to the solution,
the reaction mixture was stirred for 3 h at room temperature. Ex-
cess KCl was added to the solution to convert the cationic or coor-
dinatively unsaturated Pt complexes into the less reactive chloro-
platinum complexes. NH4Cl aq. was added to the solution and
the products were extracted with CHCl3. The organic phase was
washed with water, dried over MgSO4, filtered, and the solvent
was evaporated to give the white solid. The 1H NMR spectrum
in CDCl3, using 1,1,1,2-tetracholoroethane as an internal standard,
showed the presence of [PtCl(Ph)(cod)] (94%), [PtCl2(cod)] (4%),
and [PtPh2(cod)] (1%).
Reaction of [PtX2(cod)] with [PdPh(X0)(bpy)] (X, X0 = Cl, I).
A CH2Cl2 solution (5 cm3) of [PtCl2(cod)] (37.4 mg, 0.10 mmol)
and [PdCl(Ph)(bpy)] (37.5 mg, 0.10 mmol) was stirred for 5 days at
room temperature. The 1H NMR peak area relative to those of
1,1,1,2-tetracholoroethane used as an internal standard, showed
the presence of [PtCl(Ph)(cod)] (66%) and [PtCl2(cod)] (33%). Re-
action of [PtCl2(cod)] (37.4 mg, 0.10 mmol) with [PdI(Ph)(bpy)]
(467 mg, 1.0 mmol) in CHCl3 gave [PtI(Ph)(cod)] (96%).
The products of the reaction of [PtI2(cod)] (55.7 mg, 0.10 mmol)
with [PdI(Ph)(bpy)] (233 mg, 0.50 mmol) in CHCl3 at 50 ꢂC for 3
days were composed of [PtI(Ph)(cod)] (69%) and [PtI2(cod)]
(11%).
Experimental
General. Manipulations of the complexes were carried out un-
der nitrogen or argon using standard Schlenk techniques. Solvents
were purified in the usual manners and stored under argon. NMR
spectra (1H and 31P{1H}) were recorded on a Varian MERCU-
RY300 spectrometer. 31P{1H} NMR peak positions were refer-
enced to external 85% H3PO4. [PtCl2(cod)], [PtI2(cod)], [PtPh2-
(cod)], [PtCl(Ph)(cod)], [PtCl2(dppe)], [PtPh2(bpy)], [PdCl2(cod)],
[PdCl2(bpy)], [PdCl(ꢁ3-C3H5)]2, and [PdI(Ph)(bpy)] were pre-
pared according to the literature methods.15 [PtPh2(dppe)] and
[PdCl2(dppe)] were prepared by the reactions of dppe with
[PtPh2(cod)] and with [PdCl2(cod)], respectively. The other chem-
icals were commercially available.
Preparation of [PdCl(Ph)(bpy)].
[PdCl(Ph)(bpy)] was
known,16 but was prepared by a new procedure in this study. A
MeCN (5.0 cm3) suspension of [PdI(Ph)(bpy)] (294 mg, 0.63
mmol) was mixed with AgBF4 (180 mg, 0.93 mmol) in MeCN
(2.0 cm3). The mixture was stirred for 30 min at room temperature.
After addition of NaCl (120 mg, 2.1 mmol) to a reaction mixture,
the resulting solid was removed by filtration. Extraction of the
product by CH2Cl2 from the solid and evaporation of the solvent
gave [PdCl(Ph)(bpy)] as a white solid, which was washed with
H2O, Et2O and dried in vacuo (201 mg, 0.54 mmol, 85%).
Reaction of [PtPh2(dppe)] with [PtCl2(cod)]. A solution of
[PtPh2(dppe)] (74.8 mg, 0.10 mmol) and [PtCl2(cod)] (37.4 mg,
0.10 mmol) in CH2Cl2 (5.0 cm3) was stirred for 78 h at room tem-
perature. Evaporation of the solvent gave a mixture of the Pt com-
1
plexes as a white solid. The H NMR spectra using 1,1,1,2-tetra-
choloroethane as an internal standard showed the presence of
[PtPh2(cod)] (38%), [PtCl(Ph)(cod)] (53%), [PtCl2(cod)] (12%).
31P{1H} NMR spectrum of the products revealed the existence of
[PtCl2(dppe)] and [PtPh2(dppe)] ([PtCl2(dppe)]:[PtPh2(dppe)] =
ca. 3:1). [PtCl2(dppe)] (72%) was isolated by SiO2 column chro-
matography (eluent, CHCl3).
Reaction of [PtPh2(cod)] with [PtX2(cod)] (X = Cl, I).
A
Reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)]. A CH2Cl2
(5.0 cm3) solution of [PdCl2(cod)] (28.6 mg, 0.10 mmol) and
[PdCl(Ph)(bpy)] (37.5 mg, 0.10 mmol) was stirred for 24 h at room
temperature. After removal of an insoluble solid by filtration, the
CH2Cl2 (2.0 cm3) solution of a mixture of [PtPh2(cod)] (0.10
mmol) and [PtCl2(cod)] (0.10 mmol) was stirred for 3 h at room
temperature. Evaporation of the solvent gave the products as a
1
1
white solid. The H NMR spectrum in CDCl3 using 1,1,1,2-tetra-
solvent was evaporated to dryness. The H NMR spectrum of the
choloroethane as an internal standard showed the presence of
[PtCl(Ph)(cod)] (72%), [PtCl2(cod)] (14%), and [PtPh2(cod)]
(11%). The reaction for 24 h gave [PtCl(Ph)(cod)] (93%) and
[PtCl2(cod)] (7%). The reaction of [PtPh2(cod)] (0.20 mmol) and
[PtCl2(cod)] (0.10 mmol) for 24 h gave [PtCl(Ph)(cod)] (99%)
and [PtPh2(cod)] (42%).
products, containing 1,1,1,2-tetracholoroethane as an internal
standard, showed formation of 1 (0.039 mmol, 78%), [PdCl2(cod)]
(0.022 mmol, 22%), and [PdCl(Ph)(bpy)] (0.019 mmol, 19%). The
reaction of [PdCl2(cod)] (14.3 mg, 0.050 mmol) and [PdCl(Ph)-
(bpy)] (37.5 mg, 0.10 mmol) in CH2Cl2 (2.5 cm3) gave 1 (0.024
mmol, 96%).
A similar reaction of [PtPh2(cod)] (0.10 mmol) and [PtI2(cod)]
(0.10 mmol) for 24 h gave [PtI(Ph)(cod)] (75%), [PtPh2(cod)]
(21%), and [PtI2(cod)] (25%), while the reaction for 3 h gave
[PtI(Ph)(cod)] (36%), [PtPh2(cod)] (54%), and [PtI2(cod)] (64%)
under the same conditions. The reaction of [PtPh2(cod)] (0.20
mmol) with [PtI2(cod)] (0.10 mmol) for 24 h gave [PtI(Ph)(cod)]
(>99%) and [PtPh2(cod)] (44%).
Reaction of [PtPh2(cod)] with [PtCl2(cod)] in the Presence of
Et4NCl or KCl. A CH2Cl2 (2.0 cm3) solution of a mixture of
[PtPh2(cod)] (0.10 mmol), [PtCl2(cod)] (0.10 mmol), and Et4NCl
(188 mg, 0.53 mmol) was stirred for 3 h at room temperature.
Evaporation of the solvent and 1H NMR measurement of the resi-
due in CDCl3 showed complete recovery of the starting complexes.
The reaction in the presence of KCl (37 mg, 0.50 mmol) was car-
ried out by adding 18-crown-6 ether (130 mg, 0.49 mmol) and H2O
(0.1 cm3) to the reaction mixture. Complexes other than the start-
Reaction of [PtPh2(cod)] with [PdCl2(cod)]. A solution of
[PtPh2(cod)] (45.7 mg, 0.10 mmol) and [PdCl2(cod)] (57.1 mg,
0.20 mmol) in CH2Cl2 (1.0 cm3) was stirred for 12 h at room tem-
perature. After removal of a small amount of black solid by filtra-
tion, the solvent was evaporated to give a brown solid. The
1H NMR spectrum in CDCl3, using 1,1,1,2-tetracholoroethane as
an internal standard, showed the presence of 1 (76%), [PtCl2(cod)]
(94%), and [PdCl2(cod)] (9%).
Isolation of 1 from the Reaction on a Large Scale. A solution
of [PtPh2(cod)] (914 mg, 2.0 mmol) and [PdCl2(cod)] (1.14 g, 4.0
mmol) in CH2Cl2 (20 cm3) was stirred for 14 h at room tempera-
ture. After removal of a small amount of black solid by filtration,
the solvent was evaporated to ca. 5 cm3 to give a gray solid, which
was collected by filtration. Washing the products with CHCl3 (10
cm3, 2 times) and Et2O (10 cm3, 2 times) and drying in vacuo gave
1 as an off-white solid (860 mg, 1.3 mmol, 66%).

144 Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
Ph Ligand Transfer of Pd and Pt
Reaction of [PtPh2(dppe)] with [PdCl2(cod)]. A solution of
[PtPh2(dppe)] (74.8 mg, 0.10 mmol) and [PdCl2(cod)] (57.1 mg,
0.20 mmol) in CH2Cl2 (5.0 cm3) was stirred for 20 h at room tem-
perature. After removal of a small amount of black solid, the sol-
vent was evaporated to give a brown solid. The 1H NMR spectrum
in CDCl3, using 1,1,1,2-tetracholoroethane as an internal standard,
revealed formation of 1 (76%) and [PdCl2(cod)] (11%). The
31P{1H} NMR spectrum showed the presence of [PtCl2(dppe)]
and the absence of [PtPh2(dppe)] and [PtCl(Ph)(dppe)]. Overlap
of the 1H NMR peak of [PtCl2(dppe)] with other products prevent-
ed determination of its yield.
in the reaction mixture.
Reaction of [PtPh2(cod)] with [PdCl(ꢀ3-C3H5)]2. A solution
of [PtPh2(cod)] (46.0 mg, 0.10 mmol) and [PdCl(ꢁ3-C3H5)]2 (36.6
mg, 0.10 mmol) in acetone/CH2Cl2 (1:1 v/v, 10 cm3) was stirred
for 2 days at room temperature. Evaporation of the solvent gave a
gray solid, which was analyzed by 1H NMR in CDCl3 using
1,1,1,2-tetracholoroethane as an internal standard. The products
contained biphenyl (0.023 mmol, 5%), [PtPh2(cod)] (0.084 mmol,
84%), [PtCl(Ph)(cod)] (0.012 mmol, 12%), and [PdCl(ꢁ3-C3H5)]2
(0.094 mmol, 94%). The products of the reaction for 12 days con-
tained biphenyl (0.013 mmol, 26%), [PtPh2(cod)] (0.049 mmol,
49%), [PtCl(Ph)(cod)] (0.040 mmol, 40%), and [PdCl(ꢁ3-C3H5)]2
(0.082 mmol, 82%).
Reaction of [PtCl(Ph)(cod)] with [PdCl2(cod)]. A solution of
[PtCl(Ph)(cod)] (41.6 mg, 0.10 mmol) and [PdCl2(cod)] (28.6 mg,
0.10 mmol) in CH2Cl2 (5.0 cm3) was stirred for 14 h at room tem-
perature. Evaporation of the solvent gave a gray powder, which
This work was supported by a Grant-in-Aid for Scientific Re-
search from the Ministry of Education, Culture, Sports, Science
and Technology.
1
was analyzed by H NMR spectrum in CDCl3 using 1,1,1,2-tetra-
choloroethane as an internal standard. Both the products, 1 and
[PtCl2(cod)], were formed quantitatively.
Reaction of [PtPh2(bpy)] with [PdCl2(cod)]. A solution of
[PtPh2(bpy)] (50.5 mg, 0.10 mmol) and [PdCl2(cod)] (57.1 mg,
0.20 mmol) in CH2Cl2 (5.0 cm3) was stirred for 20 h at room tem-
perature. Although the palladium complex was dissolved, a part of
[PtPh2(bpy)] remained undissolved. After the evaporation, the
products were analyzed by 1H NMR spectrum in CDCl3 using
1,1,1,2-tetracholoroethane as an internal standard. Complex 1
was formed in 6% yield.
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Y. Suzaki et al.
Bull. Chem. Soc. Jpn., 77, No. 1 (2004)
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