Reactions of HOSiMe2Ar with Pt-PPh3 complexes leading to Si-C bond activation or formation of a siloxoplatinum complex

Article abstract of DOI:10.1016/S0022-328X(01)00796-3

PtI₂(PPh₃)₂ reacts with HOSiMe₂(C₆H₄CF₃-4) at 60°C in the presence of AgBF₄ to give a mixture of trans-PtI(C₆H₄CF₃-4)(PPh₃) ₂ (1) and [Pt₂(μ-I)₂(PPh₃)₄](BF ₄)₂ (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or NMR spectroscopy. The ³¹P{¹H}-NMR study of the reaction of AgBF₄ with PtI₂(PPh₃)₂ in acetone-d₆ revealed the formation of trans-[PtI(PPh₃)₂(acetone)]BF₄ (3) although isolation of the cationic complex was not feasible due to its facile conversion to 2. Addition of HOSiMe₂(C₆H₄CF₃-4) and Ag₂O to a toluene solution of trans-PtI(Ph)(PPh₃)₂ causes replacement of the iodo ligand with the siloxo group to afford trans-[Pt(Ph){OSiMe₂(C₆H₄CF ₃-4)}(PPh₃)₂] (4). Crystallographic results of 4 show the coordination of the phenyl, siloxo, and PPh₃ ligands to the square-planar Pt center with a large Pt-O-Si angle. Complex 4 does not decompose below 60°C in a toluene solution, but reacts with CH₂Cl₂ and CHCl₃ at room temperature to form trans-PtCl(Ph)(PPh₃)₂ (5).

Full text of DOI:10.1016/S0022-328X(01)00796-3

Journal of Organometallic Chemistry 629 (2001) 61–67
www.elsevier.com/locate/jorganchem
Reactions of HOSiMe2Ar with PtꢀPPh3 complexes leading to SiꢀC
bond activation or formation of a siloxoplatinum complex
Neli Mintcheva, Yasushi Nishihara, Atsunori Mori, Kohtaro Osakada *
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
Received 28 August 2000; received in revised form 21 March 2001; accepted 26 March 2001
Abstract
PtI2(PPh3)2 reacts with HOSiMe2(C6H4CF3-4) at 60°C in the presence of AgBF4 to give a mixture of trans-PtI(C6H4CF3-
4)(PPh3)2 (1) and [Pt2(m-I)2(PPh3)4](BF4)2 (2). Each of the complexes is isolated and characterized by X-ray crystallography and/or
NMR spectroscopy. The 31P{1H}-NMR study of the reaction of AgBF4 with PtI2(PPh3)2 in acetone-d6 revealed the formation of
trans-[PtI(PPh3)2(acetone)]BF4 (3) although isolation of the cationic complex was not feasible due to its facile conversion to 2.
Addition of HOSiMe2(C6H4CF3-4) and Ag2O to a toluene solution of trans-PtI(Ph)(PPh3)2 causes replacement of the iodo ligand
with the siloxo group to afford trans-[Pt(Ph){OSiMe2(C6H4CF3-4)}(PPh3)2] (4). Crystallographic results of 4 show the coordina-
tion of the phenyl, siloxo, and PPh3 ligands to the square-planar Pt center with a large PtꢀOꢀSi angle. Complex 4 does not
decompose below 60°C in a toluene solution, but reacts with CH2Cl2 and CHCl3 at room temperature to form trans-Pt-
Cl(Ph)(PPh3)2 (5). © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Platinum; Transmetalation; Cationic complex; Silanol; Siloxo complex
1. Introduction
oligosiloxanes indicates occurrence of SiꢀC bond acti-
vation of the silanol, which is of significant interest,
relevant not only to transition metal complex promoted
SiꢀC bond cleavage [2] but also to the mechanism of Pd
complex catalyzed synthetic organic reactions that in-
volve transmetalation of an aryl ligand of silanol to Pd
[3].
In this paper we report SiꢀC bond cleavage of silanol
promoted by cationic platinum complexes with PPh3
ligands and synthesis of a new aryl(siloxo)platinum
complex by the reaction of silanol with an iodoplat-
inum complex.
Recently, we reported that the reaction of an excess
amount of HOSiMe2(C6H4CF3-4) with a cationic plat-
inum(II) complex, [PtBr(PEt3)3]BF4, in the presence of
Ag2O gave a diarylplatinum complex accompanied by
formation of oligosiloxanes as shown in Scheme 1 [1].
The formation of the diarylplatinum complex and
2. Results and discussion
Heating a mixture of PtI2(PPh3)2, AgBF4 and fol-
lowed by addition of HOSiMe2(C6H4CF3-4) at 60°C in
acetone leads to the formation of a mixture of two Pt
complexes, trans-PtI(C6H4CF3-4)(PPh3)2 (1) (17%) and
[Pt2(m-I)2(PPh3)4](BF4)2 (2) (54%), as shown in Eq. (1).
The reaction causes separation of complex 2, which is
sparingly soluble in common organic solvents, while
complex 1 is obtained from the acetone soluble fraction
Scheme 1.
* Corresponding author. Tel./fax: +81-45-9245224.
E-mail address: kosakada@res.titech.ac.jp (K. Osakada).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00796-3

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N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
of the products. A similar reaction with added PPh3
does not cause the transmetalation but forms
[PtI(PPh3)3]BF4 which is insoluble in the solvent and
does not react further with the silanol. Fig. 1 shows the
structure of 1 determined by X-ray crystallography.
The molecule contains a crystallographically imposed
C2 symmetry around the axis, including C5, C4, C1,
Pt, and I atoms. Fluorine atoms are positioned conse-
quently at two disordered positions.
(1)
Fig. 1. ORTEP drawings of 1 at 50% ellipsoidal levels. The molecule
contains a crystallographic C2 symmetry around the C1ꢀPtꢀI axis.
The atoms with asterisks at the numbers are crystallographically
equivalent to those having the same number without the asterisk.
The 31P{1H}-NMR spectrum of 1 consists of a single
resonance at l 21.89 flanked with two satellite peaks
with 195Pt nucleus. The coupling constant (1J(PtꢀP)=
2999 Hz) is in the range of already known trans-
PtX(Ar)(PPh3)2 (X=halogeno or pseudo halogeno
,
Selected bond distances (A) and angles (°): PtꢀI, 2.7011(9); PtꢀP1,
2.316(1); PtꢀC1, 1.963(9); IꢀPtꢀP1, 90.43(5); IꢀPtꢀC1, 180.00;
P1ꢀPtꢀP1*, 179.14(9); P1ꢀPtꢀC1, 89.57(5).
1
ligands) complexes (2830–3180 Hz) [4]. The H-NMR
spectrum of 1 exhibits signals of ortho and meta hydro-
gens of 4-(trifluoromethyl)phenyl group bonded to the
Pt center. The signal at l 6.81 is flanked by 195Pt
satellite signals (3J(PtꢀH)=54 Hz) and assigned to the
ortho hydrogens, while the meta hydrogen signal ap-
pears as a simple doublet at l 6.41. The 13C{1H}-NMR
signals of the 4-(trifluoromethyl)phenyl ligand indicate
the trans configuration of 1 clearly. The Cipso signal is
observed at the lowest magnetic field position (l
154.64) as a triplet (2J(PꢀC)=8 Hz) accompanied by
195Pt satellites (1J(PtꢀC)=370 Hz).
Complex 2 gives satisfactory elemental analyses for
1
the proposed formula, but the broad H-NMR signals
of the complex do not provide further information of
the structure. The 31P{1H}-NMR spectrum in CDCl3
shows a single signal at l 14.59. The large coupling
constant with 195Pt (1J(PtꢀP)=3530 Hz) indicates that
the ligand is positioned trans to the iodo ligand with a
smaller degree of trans influence than PPh3. These
results indicate the proposed dinuclear structure with
two bridging iodo ligands unambiguously.
Fig. 2 shows results of an NMR study of an equimo-
lar reaction of AgBF4 with PtI2(PPh3)2. An acetone-d6
solution of a mixture of the two compounds exhibits
the 31P{1H}-NMR signal at l 18.93 (1J(PtꢀP)=2530
Hz) and a smaller signal of 2 at l 15.69, while the signal
of PtI2(PPh3)2 (l 13.39) is not observed at all. The
presence of BF4 counterion in the solution is demon-
strated by the precipitation of AgI during the reaction
Fig. 2. Temperature dependent 31P{1H}-NMR spectra of 3 in ace-
tone-d6. The signal at l 18–19, flanked by the satellite signals, is due
to 3, while a smaller signal with an asterisk is assigned to 2.
and by the 19F-NMR spectrum consisting of
a

N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
63
singlet at l −150.8, which is the position of the
uncoordinated BF4 anion. Variable-temperature mea-
surement of the 31P{1H}-NMR spectrum does not show
a significant change of its peak positions and coupling
constant, suggesting no occurrence of structural change
of the molecule on the NMR time scale. The major
complex in the solution is assigned to trans-
[PtI(PPh3)2(acetone)]BF4 (3) rather than its cis isomer or
[Pt(PPh3)2(acetone)2](BF4)2 based on the above results.
The coupling constant (1J(PtꢀP)=2530 Hz) is smaller
than those of common neutral Pt(II) complexes with
platinum complexes, [Pt2(m-I)2(PPh3)4](NO3)2, and a
mixture of uncharacterized products, respectively.
The reaction of the silanol with an arylplatinum
complex in the presence of a silver salt was then con-
ducted with the expectation of transmetalation of an
organic group from Si to Pt. trans-[PtPh(PPh3)2-
(solvent)]BF4, prepared in situ from trans-PtI(Ph)-
(PPh3)2 and AgBF4, reacts with the silanol to give a
mixture of several uncharacterized Pt complexes with
poor solubility in organic solvents. On the other hand,
addition of Ag2O to a toluene or THF solution of a
mixture of the silanol and trans-PtI(Ph)(PPh3)2 unex-
pectedly leads to the formation of a new phenyl-
(siloxo)platinum(II) complex, trans-PtPh{OSiMe2-
(C6H4CF3-4)}(PPh3)2 (4) in 65% yield, as shown in Eq.
(3). The siloxoplatinum complexes were prepared first
by Fukuoka and Komiya who determined the molecu-
lar structure of OSiMe3 coordinated Pt(II) complexes
and suggested their potential utility as a precursor of
inorganic materials [5]. The structure of 4 determined
by X-ray crystallography is displayed in Fig. 3. The
molecule has a typical square-planar geometry around
1
two trans PPh3 ligands. Similar difference of J(PtꢀP)
values between cationic platinum complexes with two
trans PPh3 ligands and those of the corresponding
neutral complexes is observed commonly; the coupling
constants of trans-[PtPh(CO)(PPh3)2]+ (2651 Hz) and
trans-[PtCl(C5H4NMeCl)(PPh3)2]+ (2637 Hz) are
smaller than trans-PtCl(Ph)(PPh3)2 (3152 Hz) and trans-
[PtCl(C5H4NMeCl)(PPh3)2] (3151 Hz) [4]. Thus, the
reaction of AgBF4 with PtI2(PPh3)2 gives a mixture of
complexes 2 and 3, the latter of which exists as the
major species in the solution as shown in Eq. (2). Since
addition of Et2O to the solution causes precipitation of
a solid containing 2 and PtI2(PPh3)2, due to much higher
solubility of 3 than these dinuclear complexes, isolation
of mononuclear cationic complex 3 was not successful.
,
the Pt(II) with PtꢀO bond distance (2.091(4) A) which
is longer than those of previously reported platinum
(2)
The reaction pathways giving 1 and 2 in reaction (1)
are summarized in Scheme 2. The initially formed
mononuclear cationic complex 3 dimerizes to give 2,
which tends to precipitate from the solution, or reacts
with silanol to cause transmetalation of the aryl group
of silanol to give complex 1. The reactions of the silanol
with PtI2(PPh3)2 in the presence of AgPF6, AgNO3, and
AgB(C6H3(CF3)2)4) do not give 1 via the SiꢀC bond
activation but cause formation of a mixture of fluoro-
,
complexes such as trans-PtR(OR%)(PR¦) (1.99–2.07 A)
3 2
,
[6,7] and trans-PtR(OSiR%)(PR¦) (1.99–2.00 A) [5].
3
3 2
The PtꢀOꢀSi angle (170.8(5)°) is much larger than the
PtꢀOꢀC angles observed in the alkoxo platinum com-
plexes (B125°) and the PtꢀOꢀSi angles of the siloxo
complexes (139.5–144.2°). The small PtꢀOꢀC bond an-
gles of late transition metal alkoxides have been ac-
counted for by repulsive interactions between filled dp
Scheme 2.

64
N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
heating 4 in hydrocarbon solvent does not cause SiꢀC
bond cleavage of the siloxo ligand, the siloxoplatinum
complex does not participate as an intermediate in the
transmetalation from silanol to Pt in reaction (1) and in
our previous study [1].
(4)
Thus, the reactions of HOSiMe2(C6H4CF3-4) with
PtI2(PPh3)2 in the presence of AgBF4 and with
PtI(Ph)(PPh3)2 in the presence of Ag2O produce the
iodo(aryl)platinum complex 1 and aryl(siloxo)platinum
complex 4, respectively. These results contrast with our
previous results of the reaction of the silanol with
PtBr2(PEt3)3 in the presence of AgBF4 and Ag2O giving
Pt(C6H4CF−4)2(PEt3)2. The reactions of the silanol
with Pt complexes having auxiliary PPhMe2 ligands
were conducted in order to study the effect of the kind
of phosphine ligands on the reactivity of the Pt com-
plexes. PtI2(PPhMe2)2, on heating at 60°C in the pres-
ence of the silanol and AgBF4, is converted into [Pt(m-
I)(PPhMe2)2](BF4)2 exclusively, while PtI(Ph)(PPhMe2)2
does not react with the silanol in the presence of Ag2O
at all. The low reactivity of the iodoplatinum complexes
for the transmetalation can be attributed to more stable
coordination and less-favorable dissociation of PPhMe2
than PPh3 ligand.
Fig. 3. ORTEP drawing of 4 at 50% ellipsoidal levels. One of the two
disordered positions of fluorine atoms is shown. Solvated toluene
,
molecule is omitted for simplicity. Selected bond distances (A) and
angles (°): PtꢀP1, 2.292(2); PtꢀP2, 2.294(2); PtꢀC1, 1.987(6); PtꢀO1,
2.091(4); SiꢀO1, 1.564(4); P1ꢀPtꢀP2, 175.15(6); C1ꢀPtꢀO1, 179.4(2);
PtꢀO1ꢀSi, 170.8(5); P1ꢀPtꢀC1, 92.7(2); P2ꢀPtꢀC1, 92.1(2); P1ꢀPtꢀO1,
87.8(1); P2ꢀPtꢀO1, 87.4(1).
orbital of the metal center and p orbitals of the coordi-
nated oxygen atom [8]. A severe steric repulsion be-
tween PPh3 and the bulky siloxo ligand seems to render
the PtꢀOꢀSi angle large in spite of such an interaction
between Pt and O atoms.
(3)
The present study provided the reaction of silanol
with Pt(II)ꢀPPh3 complexes to cause the transmetala-
tion of silanol giving a new PtꢀC bond or the siloxo
complex formation depending on the coexisting ligands
attached to Pt (I or Ph) and the Ag containing addi-
tives. The siloxo ligand bonded to Pt is thermally stable
and does not induce intramolecular SiꢀC bond cleavage
but reacts readily with CH2Cl2 or CHCl3 to give the
corresponding chloroplatinum complex. Further eluci-
dation of transmetalation of organosilicon compounds
to Group 10 transition metals would serve to compre-
hend the reaction mechanism of synthetic organic reac-
tions that involve these transmetalation processes.
The 1H-NMR spectrum of 4 in benzene-d6 shows
signals of the hydrogens of the phenyl ligand at l 6.80,
6.32, and 6.15. They are assigned to ortho, para, and
meta hydrogens, respectively, based on the peak posi-
tions and intensities as well as the coupling patterns.
The signals of a 4-(trifluoromethyl)phenyl group are
observed as two sets of doublets at l 7.35 and 7.21. The
upfield resonance at l −0.33 is attributed to methyl
protons bonded to Si. The single 31P-NMR signal is
1
observed at l 25.01 with J(PtꢀP) of 3277 Hz which
falls in the largest coupling constants of already re-
ported Pt(II) complexes with two trans PPh3 ligands.
Complex 4 is stable in a toluene solution at room
temperature and 60°C, while it reacts readily with
CH2Cl2 or CHCl3 even at room temperature to cause
its clean conversion into trans-PtCl(Ph)(PPh3)2 (5) (Eq.
(4)). The product exhibits reasonable NMR (1H,
31P{1H}) signals for the formula and crystallizes in the
same crystal lattices as those previously reported [9].
The above-mentioned high reactivity of the siloxoplat-
inum complex is not observed in alkoxoplatinum com-
plexes that are usually stable in CH2Cl2 solutions. Since
3. Experimental
Manipulations of the complexes were carried out
under N2 or Ar using the standard Schlenk technique.
The NMR spectra (1H, 13C, and 31P) were recorded on
JEOL EX-400 or Varian Mercury300 spectrometers at
25°C unless otherwise stated. Elemental analyses were
carried out on a Yanaco MT-5 CHN Autorecorder.
PtI2(PPh3)2 and PtI(Ph)(PPh3)2 were prepared from the

N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
65
reaction of PPh3 with PtI2(cod) and PtI(Ph)(cod), re-
spectively [10].
nals of 2 and 3 in a ca. 5:95 ratio. After concentration
of the solution to 3 or 4 cm3 under vacuum, Et2O (10
cm3) was added to cause precipitation of a yellow solid.
The 31P{1H}-NMR spectrum of the solid product con-
tains the signals of 2 and PtI2(PPh3)2 in a 30:70 ratio.
3.1. Reaction of HOSiMe2(C6H4CF3-4) with
PtI2(PPh3)2 in the presence of AgBF4
An Me2CO solution (30 cm3) of PtI2(PPh3)2 (195 mg,
0.20 mmol) and AgBF4 (39 mg, 0.20 mmol) was stirred
for 30 min at room temperature (r.t.). After removing
the precipitated AgI by filtration, HOSiMe2(C6H4CF3-
4) (44 mg, 0.20 mmol) was added to the filtrate. The
solution was heated at 60°C for 2 h, during which a
yellow solid was precipitated. The solid was collected
by filtration and dried in vacuo to give 2 as a yellow
solid (102 mg, 54%). The remained filtrate was evapo-
rated to dryness, and the yellow solid obtained was
washed with hexane (5 cm3) and then extracted with
C6H6 to remove a small amount of 2. Evaporation of
the C6H6 extract and washing of the resulting solid
product with hexane gave 1 as a pale yellow solid (33
mg, 17%). Further recrystallization from C6H5Me–hex-
ane afforded crystals for X-ray analysis grade.
3.3. Reaction of HOSiMe2(C6H4CF3-4) with
PtI(Ph)(PPh3)2 in the presence of Ag2O
To a C6H5Me (25 cm3) suspension of PtI(Ph)(PPh3)2
(323 mg, 0.35 mmol) were added Ag2O (81 mg, 0.35
mmol) and HOSiMe2(C6H4CF3-4) (93 mg, 0.42 mmol),
in this order. The reaction mixture was stirred 24 h at
r.t. The resulting gray suspension was then filtrated to
remove a gray solid, and the solid was washed with
C6H5Me (5 cm3×2). The combined filtrate and wash-
ings were evaporated to give a white solid, which was
washed with hexane (10 cm3×3) and dried in vacuo to
give 4 as a colorless solid (232 mg, 0.23 mmol, 65%).
Recrystallization from a toluene–hexane solution af-
forded colorless crystals appropriate for X-ray analysis.
Anal. Found: C, 60.45; H, 4.76; F, 5.44. Calc. for
C51H45F3OP2PtSi: C, 60.29; H, 4.46; F, 5.61%. 1H-
NMR (300 MHz, benzene-d6): l=7.74–7.67 (m, 12H,
Data for 1. Anal. Found: C, 52.17; H, 3.85; F, 5.61;
I, 10.91. Calc. for C43H34F3IP2Pt: C, 52.08; H, 3.46; F,
1
5.75; I, 12.80%. H-NMR (300 MHz, benzene-d6): l=
3
P(C6H5)3), 7.35 (d, 2H, J(HꢀH)=8 Hz, C6H4-o), 7.21
7.73–7.66 (m, 12H, C6H5), 6.98–6.96 (m, 18H, C6H5),
3
(d, 2H, J(HꢀH)=8 Hz, C6H4-m), 7.02–6.94 (m, 18H,
6.81 (d, 2H, 3J(HꢀH)=8 Hz, 3J(PtꢀH)=54 Hz,
3
3
P(C6H5)3), 6.80 (d, 2H, J(HꢀH)=8 Hz, J(PtꢀH)=49
3
PtꢀC6H4-o), 6.41 (d, 2H, J(HꢀH)=8 Hz, PtꢀC6H4-m).
Hz, PtꢀC6H5-o), 6.32 (t, 1H, 3J(HꢀH)=7 Hz, PtꢀC6H5-
p), 6.15 (t, 2H, J(HꢀH)=7 Hz, C6H5-m), −0.33 (s,
31P{1H}-NMR (121.5 MHz, benzene-d6): l=21.89 (s,
1J(PtꢀP)=2999 Hz). 13C{1H}-NMR (75.3 MHz,
3
6H, CH3). 31P{1H}-NMR (121.5 MHz, benzene-d6):
l=25.01 (s, 1J(PtꢀP)=3277 Hz). 13C{1H}-NMR
(100.4 MHz, THF-d8): l=153.67 (br, PtꢀC6H5-ipso),
139.47 (s, PtꢀC6H5-o), 139.44 (s, SiꢀC6H4-ipso), 135.91
(vt, J=6 Hz, PꢀC6H5-o), 134.36 (q, J=9 Hz, SiꢀC6H4-
p), 134.24 (s, SiꢀC6H4-o), 131.70 (vt, J=26 Hz,
PꢀC6H5-ipso), 130.75 (s, PꢀC6H5-p), 128.57 (vt, J=6
Hz, PꢀC6H5-m), 127.44 (s, PtꢀC6H5-m), 125.96 (q, J=
1
2
CDCl3): l=154.64 (t, J(PtꢀC)=370 Hz, J(PꢀC)=8
3
Hz, PtꢀCipso), 136.03 (t, J(PꢀC)=3 Hz, PtꢀC6H4-o),
2
134.87 (vt, J=6 Hz, PꢀC6H5-o), 130.90 (q, J(FꢀC)=
58 Hz, PtꢀC6H4-p), 130.70 (vt, J=28 Hz, PꢀC6H5-
1
ipso), 130.09 (s, PꢀC6H5-p), 127.93 (q, J(FꢀC)=190
Hz, CF3), 127.70 (vt, J=5 Hz, PꢀC6H5-m), 123.22 (q,
3J(PtꢀC)=67 Hz, 3J(FꢀC)=4 Hz, PtꢀC6H4-m).
19F{1H}-NMR (188.2 MHz, benzene-d6): l= −61.56
(s). Data for 2. Anal. Found: C, 46.62; H, 3.31; F, 6.40;
I, 13.48. Calc. for C72H60P4B2F8I2Pt2: C, 46.33; H, 3.24;
3
272 Hz, CF3), 123.54 (q, J(FꢀC)=4 Hz, SiꢀC6H4-m),
120.82 (s, PtꢀC6H5-p), 2.84 (s, CH3).
1
F, 8.14; I, 13.60%. H-NMR (300 MHz, CDCl3): l=
7.35 (br, C6H5). 31P{1H}-NMR (121.5 MHz, CDCl3):
3.4. Reaction of HOSiMe2(C6H4CF3-4) with
trans-[PtPh(PPh3)2]BF4 in the presence and absence of
Ag2O
l=14.59 (s, 1J(PtꢀP)=3530 Hz); (161.5 MHz, ace-
1
tone-d6): l=15.69 (s, J(PtꢀP)=3525 Hz).
A similar reaction with addition of PPh3 caused
separation of insoluble [PtI(PPh3)3]BF4 from the solu-
tion and did not give 1 at all.
To a THF or C6H5Me (5 cm3) solution of PtI(Ph)-
(PPh3)2 (195 mg, 0.21 mmol) was added AgBF4 (39 mg,
0.20 mmol), and the mixture was stirred for 30 min.
The residue of AgI and insoluble Pt complexes was
formed. HOSiMe2(C6H4CF3-4) (44 mg, 0.20 mmol) or a
mixture of the silanol (44 mg, 0.20 mmol) and Ag2O (46
mg, 0.20 mmol) was added to the above reaction mix-
ture. Heating the mixture did not cause significant
conversion of the initially formed cationic phenylplat-
inum species.
3.2. Reaction of AgBF4 with PtI2(PPh3)2
To an Me2CO solution (10 cm3) of PtI2(PPh3)2 (195
mg, 0.20 mmol) was added AgBF4 (39 mg, 0.20 mmol),
and the mixture was stirred for 30 min at r.t. The
precipitated AgI was removed by filtration. The
31P{1H}-NMR spectrum of the solution shows the sig-

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N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
3.5. Reaction of HOSiMe2(C6H4CF3-4) with
PtI2(PPhMe2)2
r.t. under Ar. Complete dissolution of 4 required 10
min or longer. The 31P{1H}-NMR spectrum obtained
soon after dissolution contained the signals of 4 and 5
in ca. 1:2 peak area ratio.
To an NMR tube containing AgBF4 (25 mg, 0.13
mmol) was introduced PtI2(PPhMe2)2 (28 mg, 0.038
mmol) and acetone-d6 (0.7 cm3) under Ar atmosphere.
After the reaction for 1 h at r.t. the 31P{1H}-NMR
spectrum indicates disappearance of the signals of the
starting complex (l −10.78, cis form, J(PtꢀP)=3370
Hz and l −16.84, trans form, J(PtꢀP)=2308 Hz) and
existence of a new signal at l −5.00 (J(PtꢀP)=3452
Hz) as the dominant signal. The signal is assigned to
[Pt(m-I)(PPhMe2)2](BF4)2. Heating the reaction mixture
for 72 h at 60°C did not cause a significant change of
the NMR spectra.
Recrystallization of
4 from CH2Cl2–hexane or
CHCl3–hexane afforded 5 as colorless crystals. The
lattice parameters of the obtained crystals (orthorhom-
,
bic, a=11.79(1), b=23.75(1), c=25.55(1) A with
Pbca) were the same as those reported previously (or-
thorhombic, a=11.800(4), b=23.705(2), c=25.549(5)
,
A with the same space group) [9]. Data for 5. Anal.
Found: C, 60.81; H, 4.35; Cl, 4.28. Calc. for
1
C42H35P2ClPt: C, 60.62; H, 4.24; Cl, 4.26%. H-NMR
(300 MHz, CDCl3): l=7.52 (m, 12H, P(C6H5)3), 7.28
(m, 18H, P(C6H5)3), 6.65 (d, 2H, J(HꢀH)=7 Hz,
J(PtꢀH)=48 Hz, C6H4-o), 6.27 (t, 1H, J(HꢀH)=8 Hz,
C6H4-p), 6.10 (t, 2H, J(HꢀH)=7 Hz, C6H4-m).
31P{1H}-NMR (121.5 MHz, CDCl3): l=25.03 (s,
1J(PtꢀP)=3150 Hz).
3.6. Reaction of HOSiMe2(C6H4CF3) with
PtI(Ph)(PPhMe2)2
To an NMR tube containing PtI(Ph)(PPhMe2)2 (39
mg, 0.057 mmol) was introduced acetone-d6 (0.7 cm3),
Ag2O (13 mg, 0.057 mmol), and HOSiMe2(C6H4CF3-4)
(13 mg, 0.057 mmol) under Ar atmosphere. After the
reaction for 24 h at r.t. the 31P{1H}-NMR spectrum
contains signals of PtI(Ph)(PPhMe2)2 (l −11.27,
J(PtꢀP)=2797 Hz) only. Heating of the reaction mix-
ture for 6 h at 60°C did not cause change of the spectra.
3.8. X-ray crystallography
Crystals of 1 and 4 suitable for X-ray diffraction
study were obtained by recrystallization from
C6H5Me–hexane and mounted in glass capillaries un-
der Ar. Data were collected at 23°C on a Rigaku
AFC-5R or -7R automated four-circle diffractometer
equipped with monochromated Mo–Ka radiation (u=
3.7. Reaction of 4 with CH2Cl2 or CHCl3
,
0.71073 A). Calculations were carried out using a pro-
gram package TEXSAN for Windows. The structures
were solved by a combination of heavy atom method
and subsequent Fourier techniques. All non-hydrogen
atoms were refined anisotropically. The hydrogen
atoms were located by assuming the ideal geometry and
included in the structure calculation without further
refinement of the parameters. Crystallographic data
and details of refinement are summarized in Table 1.
To complex 4 in an NMR tube was added CDCl3 at
Table 1
Crystallographic data and details of structure refinement
Complex
Formula
1
4
C
43H34F3IP2Pt
C51H45F3OP2-
SiPt·C3.5H4
Formula weight
Dimensions (mm)
Crystal system
991.68
1108.03
0.55×0.30×0.20
Monoclinic
0.43×0.35×0.33
Monoclinic
C2/c (No. 15)
4. Supplementary material
Space group
C2/c (No. 15)
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 148989 and 148990 for com-
pounds 1 and 4, respectively. Copies of this information
may be obtained free of charge from The Director,
CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK
Unit cell dimensions
,
a (A)
25.285(2)
13.736(2)
11.549(2)
112.44(2)
3707.5(8)
4
1.777
1920
4.735
9053
26.902(5)
11.469(3)
32.689(3)
105.69(1)
9710(3)
8
1.368
4264
3.056
11887
,
b (A)
,
c (A)
i (°)
3
,
V (A )
Z
(Fax:
+44-1223-336033;
e-mail:
deposit@ccdc.
zc (g cm−3
F(000)
)
cam.ac.uk or www: http://www.ccdc.cam.ac.uk).
v (Mo–Ka) (mm−1
)
Measured reflections
Used reflections
[I\3.0|(I)]
3578
6532
Acknowledgements
Variables
R (Rw)
227
0.035 (0.036)
545
0.045 (0.036)
This work was supported financially by a Grant-in-
aid for Scientific Research from the Ministry of Educa-

N. Mintche6a et al. / Journal of Organometallic Chemistry 629 (2001) 61–67
67
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