Disproportionation of PtPh(CH2COMe)(cod) and conproportionation of PtPh2(cod) and Pt(CH2COMe)2(cod) via intermolecular phenyl ligand transfer

Article abstract of DOI:10.1021/om0204991

PtI(Ph)(cod) (cod = 1,5-cyclooctadiene) reacts with acetone in the presence of Ag₂O to give a mixture of Pt(CH₂COMe)(Ph)(cod) (1), PtPh₂(cod) (2), and Pt(CH₂COMe)₂(cod) (3) in a molar ratio of 61:20:19. Complex 1, having the phenyl and acetonyl ligands, was isolated by recrystallization of the products and characterized by X-ray crystallography. The reaction of AgBF₄ with PtI(Ph)(cod) forms [PtPh(cod)(acetone-d₆)]BF₄ and does not give a diarylplatinum complex. Thus, Ag₂O, in the reaction of PtI(Ph)(cod) with acetone, promotes activation of both the Pt-I bond of PtI(Ph)(cod) and a C-H bond of acetone. Heating of 1 in acetone at 50 °C causes its partial disproportionation into 2 and 3 to give a mixture of the above three complexes. An equimolar mixture of 2 and 3 in acetone undergoes conproportionation into 1 at 50 °C to give a mixture of the complexes. The conproportionation is completed in 30 h to form the mixture with [1]:[2]:[3] = 66:17:17, while the above disproportionation of 1 does not attain equilibrium even after 70 h. The disproportionation and conproportionation of these complexes are observed also in benzene at 50 °C.

Full text of DOI:10.1021/om0204991

5254
Organometallics 2002, 21, 5254-5258
Disp r op or tion a tion of P tP h (CH2COMe)(cod ) a n d
Con p r op or tion a tion of P tP h 2(cod ) a n d
P t(CH2COMe)2(cod ) via In ter m olecu la r P h en yl Liga n d
Tr a n sfer
Yuji Suzaki, Takeyoshi Yagyu, Yuichi Yamamura, Atsunori Mori, and
Kohtaro Osakada*
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8503, J apan
Received J une 25, 2002
PtI(Ph)(cod) (cod ) 1,5-cyclooctadiene) reacts with acetone in the presence of Ag2O to give
a mixture of Pt(CH2COMe)(Ph)(cod) (1), PtPh2(cod) (2), and Pt(CH2COMe)2(cod) (3) in a molar
ratio of 61:20:19. Complex 1, having the phenyl and acetonyl ligands, was isolated by
recrystallization of the products and characterized by X-ray crystallography. The reaction
of AgBF4 with PtI(Ph)(cod) forms [PtPh(cod)(acetone-d6)]BF4 and does not give a diaryl-
platinum complex. Thus, Ag2O, in the reaction of PtI(Ph)(cod) with acetone, promotes
activation of both the Pt-I bond of PtI(Ph)(cod) and a C-H bond of acetone. Heating of 1 in
acetone at 50 °C causes its partial disproportionation into 2 and 3 to give a mixture of the
above three complexes. An equimolar mixture of 2 and 3 in acetone undergoes conpropor-
tionation into 1 at 50 °C to give a mixture of the complexes. The conproportionation is
completed in 30 h to form the mixture with [1]:[2]:[3] ) 66:17:17, while the above
disproportionation of 1 does not attain equilibrium even after 70 h. The disproportionation
and conproportionation of these complexes are observed also in benzene at 50 °C.
Sch em e 1
In tr od u ction
Several monoalkyl (or monoaryl) complexes of Ni(II)
and Pd(II) were reported to undergo intermolecular
coupling of the organic ligands, which involves initial
disproportionation of the complex to form the dialkyl
(or diaryl) complexes followed by intramolecular cou-
pling of the alkyl (or aryl) ligands.1,2 Analogous dispro-
portionation of the monoarylplatinum complex would
produce stable diarylplatinum complexes which do not
undergo coupling of the ligands easily.3 There have been
only a few reports of such an intermolecular aryl ligand
transfer of arylplatinum triflate, giving a diarylplatinum
complex.
Peters et al. recently reported the reaction of arene
with PtMe(OCOCF3)(dmpe) (dmpe ) 1,2-bis(dimeth-
ylphosphino)ethane), which causes initial formation of
an arylplatinum acetato complex via Pt complex pro-
moted C-H bond activation of the arene and dispro-
portionation of the formed PtAr(OCOCF3)(dmpe) into
a mixture of the three complexes shown in Scheme 1.4
The reaction of benzene at 50 °C produces PtPh-
(OCOCF3)(dmpe) in a yield higher than 90% accompa-
nied by formation of much smaller amounts of PtPh2-
(dmpe) and Pt(OCOCF3)2(dmpe). 1,2-Difluorobenzene
reacts with the methylplatinum complex to form a
mixture of the three complexes in a 1:2:1 molar ratio.
The latter reaction, which gives the products in a
statistical ratio, may suggest reversibility of the dis-
proportionation, whereas the reverse reaction, conpro-
portionation of a mixture of the diphenyl- and diace-
tatoplatinum complexes, was not studied.
In this paper, we report smooth intermolecular phenyl
ligand transfer of the Pt complexes with an acetonyl
ligand to cause disproportionation of Pt(CH2COMe)Ph-
(cod) to give PtPh2(cod) and Pt(CH2COMe)2(cod) and
conproportionation of the diaryl- and diacetonylplati-
num complexes.
(1) (a) Yagyu, T.; Hamada, M.; Osakada, K.; Yamamoto, T. Orga-
nometallics 2001, 20, 1087. (b) Yamamoto, T.; Kohara, T.; Yamamoto,
A. Bull. Chem. Soc. J pn. 1981, 54, 2010.
(2) Scott, J . D.; Puddephatt, R. J . Organometallics 1983, 2, 1463.
(3) Braterman, P. S.; Cross, R. J .; Young, G. B. J . Chem. Soc., Dalton
Trans. 1977, 1892.
(4) Peters, R. G.; White, S.; Roddick, D. M. Organometallics 1998,
17, 4493.
Resu lts a n d Discu ssion
Acetonylplatinum complexes such as PtCl(CH2COMe)-
(bpy), Pt(CH2COMe)2(bpy), and PtCl(CH2COMe)(PEt3)2
10.1021/om0204991 CCC: $22.00 © 2002 American Chemical Society
Publication on Web 10/26/2002

Disproportionation of PtPh(CH2COMe)(cod)
Organometallics, Vol. 21, No. 24, 2002 5255
were prepared from the reactions of acetone with
dichloroplatinum complexes in the presence of Ag2O.5,6
The above-reported complexes with N- and P-donor
ligands are stable in solution. We examined the prepa-
ration of new reactive acetonylplatinum complexes by
using the cod ligand, which is more labile than the
chelating diamine or phosphine ligands.7,8
Heating an acetone solution of PtI(Ph)(cod) with Ag2O
at 50 °C produced a mixture of the complexes Pt(CH2-
COMe)(Ph)(cod) (1), PtPh2(cod) (2), and Pt(CH2COMe)2-
(cod) (3) in a ratio of 61:20:19, as shown in eq 1. The
F igu r e 1. ORTEP drawing of complex 1 with 30% prob-
ability ellipsoids. Selected bond distances (Å) and angles
(deg): Pt-C1 ) 2.03(4), Pt-C4 ) 2.04(3), Pt-C10 )
2.28(2), Pt-C11 ) 2.29(3), Pt-C14 ) 2.40(4), Pt-C15 )
2.25(3), C2-O1 ) 1.25(3), C1-C2 ) 1.58(3), C2-C3 )
1.48(5); C1-Pt-C4 ) 89(3), Pt-C1-C2 ) 113(3), C1-C2-
C3 ) 117(3).
product that was insoluble in acetone was assigned to
AgI on the basis of a comparison of the X-ray powder
diffraction pattern with the standard data.9 Complex 1
was isolated in 30% yield by recrystallization of the
products from hexane and characterized by X-ray
crystallography and NMR spectroscopy. Figure 1 depicts
the molecular structure of 1, which has a distorted-
square-planar coordination around the Pt center bonded
to both phenyl and acetonyl ligands at cis positions. The
F igu r e 2. Profile of the reaction of acetone with PtI(Ph)-
(cod) in NMR tube scale reactions: [PtI(Ph)(cod)]0 ) 2.0 ×
10-2 M.
1
CH2 and CH3 groups of the acetonyl ligand exhibit H
and 13C{1H} NMR signals at reasonable positions and
with splitting due to the 195Pt nucleus (δH 2.85 (CH2,
J (PtH) ) 125 Hz) and 1.62 (CH3, J (PtH) ) 16 Hz); δC
41.7 (CH2, J (PtC) ) 616 Hz) and 30.4 (CH3, J (PtC) ) 6
Hz)).
initial formation of 1 followed by its disproportionation.
Figure 2 shows the profile of the reaction, which was
1
monitored by change of the H NMR peak areas of the
The above reaction mixture exhibits NMR signals of
the cod ligand of 210 and those of the acetonyl and cod
ligands of 3, which was prepared separately from the
reaction of Ag2O with PtCl2(cod) in acetone at 50 °C.
Formation of these complexes by reaction 1 suggests
dCH- hydrogen of COD during the reaction. PtI(Ph)-
(cod) at 2.0 × 10-2 M reacts with acetone in the presence
of Ag2O to afford complexes 1-3 in a 74:15:11 molar
ratio after 20 h. The gradual increase of 2 and 3
throughout the reaction and even after consumption of
PtI(Ph)(cod) indicates the occurrence of a disproportion-
ation of the initially formed complex 1. Recently, we
reported that cationic palladium complexes, [PdAr-
(acetone)(bpy)]+BF4-, underwent facile disproportion-
ation to give PdAr2(bpy), followed by rapid coupling of
biaryl.1a Addition of AgBF4, instead of Ag2O, to PtI(Ph)-
(cod) in acetone-d6 produces an analogous Pt complex,
[Pt(Ph)(acetone-d6)(cod)]+BF4- (4). Heating an acetone-
d6 solution of 4 at 50 °C does not form 1 or 2 and causes
slow decomposition of the complex only.11 Thus, the
cationic phenylplatinum complex 4 does not undergo
disproportionation via intermolecular phenyl ligand
transfer.
The role of Ag2O in the reaction (1), which involves
formation of 1 and its disproportionation, is of signifi-
cant interest. Ag2O serves to convert PtI(Ph)(cod) into
1 via activation of not only the Pt-I bond of PtI(Ph)-
(cod) but also a C-H bond of acetone, similar to the
reaction of acetone with dichloroplatinum complexes.7
This is in contrast with the above results that AgBF4
abstracts an iodo ligand of PtI(Ph)(cod) but does not
(5) (a) Cross, R. J .; Anderson, G. K.; Young, G. B. In Comprehensive
Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson,
G. Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 9, Chapters 7-9.
(b) Rendina, L. M.; Puddephatt, R. J . Chem. Rev. 1997, 97, 1735. (c)
Belluco, U.; Bertani, R.; Michelin, R. A.; Mozzon, M. J . Organomet.
Chem. 2000, 600, 37.
(6) (a) Periana, R. A.; Taube, D. J .; Gamble, S.; Taube, H.; Satoh,
T.; Fujii, H. Science 1998, 280, 560. (b) J ohansson, L.; Tilset, M.;
Labinger, J . A.; Bercaw, J . E. J . Am. Chem. Soc. 2000, 122, 10846. (c)
Peters, R. G.; White, S.; Roddick, D. M. Organomoetallics 1998, 17,
4493. (d) Albrecht, M.; Dani, P.; Lutz, M.; Spek, A. L.; van Koten, G.
J . Am. Chem. Soc. 2000, 122, 11822. (e) Sanchez, A.; Castellari, C.;
Panunzi, A.: Vitagliano, A.; De Felice, V. J . Organomet. Chem. 1990,
388, 243. (f) De Felice, V.; De Renzi, A.; Tesauro, D.; Vitagliano, A.
Organometallics 1992, 11, 3669. (g) De Felice, V.; Cucciolito, M. E.;
De Renzi, A.; Ruffo, F.; Tesauro, D. J . Organomet. Chem. 1995, 493,
1. (h) De Felice, V.; De Renzi, A.; Ferrara, M. L.; Panunzi, A. J .
Organomet. Chem. 1996, 513, 97.
(7) (a) Cairns, M. A.; Dixon, K. R.; Smith, M. A. R. J . Organomet.
Chem. 1977, 135, C33. (b) Falvello, L. R.; Garde, R.; Miqueleiz, E. M.;
Toma´s, M.; Urriolabeitia, E. P. Inorg. Chim. Acta 1997, 264, 297. (c)
Vicente, J .; Abad, J . A.; Chicote, M.-T.; Abrisqueta, M.-D.; Lorca, J .-
A.; de Arellano, M. C. R. Organometallics 1998, 17, 1564.
(8) Synthesis of Pt-acetonyl complexes by other methods: (a)
Arnold, D. P.; Bennet, M. A. J . Organomet. Chem. 1980, 199, 119. (b)
Almeida, J . F.; Pidcock, A. J . Organomet. Chem. 1981, 209, 415. (c)
Yamamoto, H.; Suzuki, K. J . Organomet. Chem. 1974, 71, C38. (d)
Suzuki, K.; Yamamoto, H. Inorg. Chim. Acta 1993, 208, 225. (e)
Appleton, T. G.; Bennet, M. A. Inorg. Chem. 1978, 17, 738.
(9) J CPDS Powder Diffraction File.
(11) [Pt(Ph)(acetone)(bpy)]BF4 does not undergo the disproportion-
ation. See: Yagyu, T.; Suzaki, Y.; Osakada, K. Organometallics 2002,
21, 2088.
(10) Clark, H. C.; Manzer, L. E. J . Organomet. Chem., 1973, 59,
411.

5256 Organometallics, Vol. 21, No. 24, 2002
Suzaki et al.
Sch em e 2
gest the presence of an equilibrium among the com-
plexes via disproportionation and conproportionation.
The disproportionation in Figure 3a, however, seems to
attain equilibrium after much longer periods than the
conproportionation in Figure 3b.14 The profile of the
conproportionation with addition of Ag2O is similar to
that of Figure 3b, which implies that transfer of the aryl
ligand is not influenced by Ag2O in the reaction.
F igu r e 3. (a) Profile of disproportionation of 1 into 2 and
3 in acetone-d6 at 50 °C. (b) Profile of conproportionation
of 2 and 3 into 1 in acetone-d6 at 50 °C.
form the acetonyl ligand. Previously, the reaction of
water with PtCl2(bpy) in the presence of Ag2O was
reported to afford Pt(OH)2(bpy).12 Ag2O activates the
Pt-I bond of PtI(Ph)(PPh3)2 in the presence of HOSi-
Me2(C6H4CF3) to afford the siloxoplatinum complex
trans-PtPh{OSiMe2(C6H4CF3)}(PPh3)2.13 Ag2O plays a
dual role also in these reactions; it eliminates the Cl or
I ligand of the complex to give AgCl or AgI and abstracts
a proton of water or silanol to form the OH (or OR)
ligand of the resulting Pt complexes. Activation of the
Pt-Cl or Pt-I bonds of the complexes by Ag2O forms
AgO- with a high basicity. The AgO- group, which
coordinates to the Pt center or exists as the counteran-
ion of the cationic Pt complex, is able to abstract a
proton from acetone to produce the acetonyl ligand
bonded to Pt of the complexes.
The disproportionation and conproportionation in
acetone-d6 involve intermolecular transfer of the
acetonyl ligand among the complexes. The 1H NMR
spectrum of a mixture of the three complexes in acetone-
d6 contains the signals of the acetonyl ligand of 1 at δ
2.84 and 1.56. Heating the solution at 50 °C for 72 h
causes a decrease of the signals of the acetonyl ligand
accompanied by growth of the signal of acetone, in 27%
of the original complex (Scheme 2). Exchange of the
acetonyl group between the complex and the solvent15
occurs slowly. These results indicate that the reaction
(2) proceeds not via predissociation of the acetonyl
ligand from Pt but via intermolecular ligand exchange.
The reaction of Ag2O and PtI(Ph)(cod) in toluene
Heating of 1 in acetone at 50 °C causes its partial
disproportionation into 2 and 3 to give a mixture of the
three complexes ([1]:[2]:[3] ) 75:13:12 after 70 h), as
shown in eq 2. Figure 3a plots the change of concentra-
1
forms complex 2 in 31% (yield by NMR). The H NMR
spectrum of the reaction mixture showed gradual de-
composition of once formed 3 and liberation of cod from
Pt in this solvent. Figure 4 depicts the profiles of
conproportionation of a mixture of 2 and 3 into 1 and
of disproportionation of 1 into 2 and 3 in benzene-d6,
1
monitored by H NMR spectroscopy. The disproportion-
ation takes place to a small extent, giving a mixture of
the complexes with a much higher molar ratio of 1 than
2 and 3. The conproportionation takes place steadily
over 60 h and may attain the equilibrium after a longer
period, although the partial decomposition of 3 during
the reaction prevented further plotting of the reaction
profile.
The aryl and acetonyl ligand transfer of the Pt
complexes with COD ligand takes place both in acetone
and in benzene. Influence of the solvent on the reactions
is observed but is not so significant. Dissociation of the
acetonyl ligand as an ion species or concerted exchange
of the acetonyl group between the ligand and acetone
solvent does not occur in the intermolecular ligand
tion of the complexes during disproportionation of 1
(initial concentration 8.0 × 10-2 M) at 50 °C. Conversion
of 1 into 2 and 3 proceeds gradually for 45 h or longer.
Heating an acetone solution of an equimolar mixture
of 2 and 3 causes their conproportionation to give 1, as
shown in eq 3. The profile of the reaction for the mixture
with [2]0 ) [3]0 ) 4.0 × 10-2 M is shown in Figure 3b.
This saturation of increase of [1] and the occurrence of
the conpoportionation and disproportionation in the
independent experiments under similar conditions sug-
(14) The increase of 1 in Figure 3 obeys second-order kinetics,
although the precise rate constants were not determined from the plots.
(15) See, for analogous ligand exchange of an aryloxido ligand
bonded to a transition metal with phenol, accompanied by proton
exchange: Osakada, K.; Ohshiro, K.; Yamamoto, A. Organometallics
1991, 10, 404.
(12) Wimmer, S.; Castan, P.; Wimmer, F. L.; J ohnson, N. P. J . Chem.
Soc., Dalton Trans. 1989, 403.
(13) Mintcheva, N.; Nishihara, Y.; Tanabe, M.; Hirabayashi, K.;
Mori, A.; Osakada, K. Organometallics 2001, 20, 1243.

Disproportionation of PtPh(CH2COMe)(cod)
Organometallics, Vol. 21, No. 24, 2002 5257
PtPh2(cod) were prepared according to the literature meth-
ods.10 Solvents were purified in the usual manner and stored
under argon. The other chemicals were commercially available.
IR and NMR spectra were recorded on a Shimadzu FTIR-
8100A spectrophotometer and a Varian MERCURY300 spec-
trometer, respectively. Elemental analyses were carried out
with a Yanaco MT-5 CHN autocorder.
Rea ction of Ag2O w ith [P tI(P h )(cod )] in Aceton e.
P r ep a r a tion of [P t(CH2COMe)(P h )(cod )] (1). A mixture of
[PtI(Ph)(cod)] (1.42 g, 2.80 mmol) and Ag2O (817 mg, 3.54
mmol) in acetone (20 mL) was heated at 50 °C for 3 days with
stirring. [PtI(Ph)(cod)] was dissolved at 50 °C, while most of
the Ag2O remained undissolved. The initial colorless solution
became yellow during stirring. The insoluble black solid was
separated by filtration and subjected to wide-angle X-ray
powder diffraction analysis. The solution was concentrated
under reduced pressure and eluted by SiO2 chromatography
(1:1 CHCl3/AcOEt). Recrystallization of the product from
hexane at -20 °C gave colorless microcrystals of 1, which were
collected by filtration, washed with cold hexane, and dried in
1
vacuo. Yield: 384 mg, 30%. H NMR data for complex 1 (300
F igu r e 4. (a) Profile of disproportionation of 1 into 2 and
3 in benzene-d6 at 50 °C. (b) Profile of conproportionation
of 2 and 3 into 1 in benzene-d6 at 50 °C.
MHz, CDCl3): δ 1.62 (s, 3H, CH3, J (PtH) ) 16 Hz), 2.2-2.4
(4H, CH2-cod), 2.85 (s, 2H, Pt-CH2, J (PtH) ) 125 Hz), 4.76
(m, 2H, CH-cod, J (PtH) ) 48 Hz), 5.38 (m, 2H, CH-cod, J (PtH)
) 37 Hz), 6.88 (m, 1H, C6H5-p), 7.07 (m, 2H, C6H5-m), 7.20
(m, 2H, C6H5-o, J (PtH) ) 59 Hz). 1H NMR data (300 MHz,
acetone-d6): δ 1.56 (s, 3H, CH3, J (PtH) ) 13 Hz), 2.3-2.6 (4H,
CH2-cod), 2.84 (s, 2H, Pt-CH2, J (PtH) ) 58 Hz), 4.80 (m, 2H,
CH-cod, J (PtH) ) 35 Hz), 5.40 (m, 2H, CH-cod, J (PtH) ) 34
Hz), 6.85 (m, 1H, C6H5-p), 7.04 (m, 2H, C6H5-m), 7.23 (m, 2H,
C6H5-o, J (PtH) ) 59 Hz). 13C{1H} NMR data for complex 1
(75.5 MHz, CDCl3): δ 29.2 (CH2-cod), 30.2 (CH2-cod, J (PtH)
) 37 Hz), 30.4 (CH3, J (PtC) ) 6 Hz), 41.7 (Pt-CH2, J (PtC) )
616 Hz), 100.1 (CH-cod, J (PtC) ) 81 Hz), 107.5 (CH-cod, J (PtC)
) 43 Hz), 123.1 (C6H5-p, J (PtC) ) 104 Hz), 128.0 (C6H5-m,
J (PtC) ) 67 Hz), 134.4 (C6H5-o, J (PtC) ) 27 Hz), 153.4 (C6H5-
ipso, J (PtC) ) 996 Hz), 211.7 (CO, J (PtC) ) 44 Hz). IR (KBr):
ν(CdO) 1646 cm-1. Anal. Calcd for C17H22OPt: C, 46.68; H,
5.07. Found: C, 46.31; H, 5.09.
Sch em e 3
transfer. Scheme 3 depicts the possible pathways to
account for the above results. Association of two mol-
ecules of 1 forms the intermediate A with bridging
phenyl and acetonyl ligands bonded to two Pt centers.
Bridging coordination of a phenyl ligand of 2 and an
acetonyl ligand of 3 also forms the intermediate A,
which is split into the two molecules of 1. Activation of
the two Pt-C bonds of A produces 2 and 3 via dispro-
portionation. Bridging coordination of a phenyl ligand
of 2 and an acetonyl ligand of 3 also forms the inter-
mediate A, which is split into two molecules of 1 in the
conproportionation. The disproportionation of 1 and the
conproportionation of 2 and 3 involve the common
intermediate A in these reactions. The higher reactivity
of the Pt-acetonyl bond of 3 as compared to that of 1
may cause more rapid attainment to the equilibrium
in conproportionation than disproportionation.
P r ep a r a tion of [P t(CH2COMe)2(cod )] (3). An acetone
(6.5 mL) solution of a mixture of [PtCl2(cod)] (257 mg, 0.687
mmol) and Ag2O (505 mg, 2.8 mmol) was heated at 50 °C for
12 h with stirring. The insoluble black solid was separated by
filtration. Recrystallization of the product from CH2Cl2/hexane
at -20 °C gave 3 as a brown powder which was collected by
filtration, washed with cold hexane, and dried in vacuo (82
mg, 29%). 1H NMR data of 3 (300 MHz, CDCl3): δ 2.08 (s, 6H,
CH3, J (PtH) ) 12 Hz), 2.33 (br, 8H, CH2-cod), 2.89 (s, 4H,
PtCH2, J (PtH) ) 114 Hz), 5.13 (br, 4H, CH-cod, J (PtH) ) 45
Hz). 13C{1H} NMR data for complex 1 (75.5 MHz, CDCl3): δ
29.2 (CH2-cod), 30.3 (CH3), 37.9 (PtCH2, J (PtC) ) 598 Hz),
102.5 (CH-cod, J (PtC) ) 74 Hz), 210.4 (CO, J (PtC) ) 39 Hz).
IR (KBr): ν(CdO) 1642 cm-1
.
Rea ction of AgBF 4 w ith [P tI(P h )(cod )] in Aceton e-d 6.
A mixture of [PtI(Ph)(cod)] (6.7 mg, 0.013 mmol) and AgBF4
(2.6 mg, 0.013 mmol) dispersed in acetone-d6 (0.5 mL) in a
Schlenk flask was stirred for ca. 1 min at room temperature.
AgI, separated soon from the solution, was removed by
filtration. The solution was transferred to an NMR tube under
Ar. The 1H NMR spectrum showed consumption of [PtI(Ph)-
(cod)] and generation of the signals of [Pt(Ph)(acetone-d6)(cod)]+-
In summary, a Pt complex with aryl and acetonyl
ligands was prepared at first. It undergoes dispropor-
tionation into the diarylplatinum and diacetonylplati-
num complexes both in acetone and in benzene, al-
though concomitant conproportionation of the products
results in formation of a mixture of these three com-
plexes. This study revealed that the organic ligands
bonded to the Pt complexes without ionic ligands are
able to undergo the intermolecular transfer via activa-
tion of the Pt-C bonds.
.
1H NMR data for [Pt(Ph)(acetone-d6)(cod)]+BF4 (300
-
-
BF4
MHz, acetone-d6): δ 2.5-2.8 (8H, CH2-cod), 4.86 (2H, CH2-
cod, J (PtH) ) 91 Hz), 5.99 (2H, CH2-cod, J (PtH) ) 33 Hz),
6.99 (m, 1H, C6H5-p), 7.08 (m, 2H, C6H5-m), 7.26 (m, 2H, C6H5-
o, J (PtH) ) 49 Hz).
Exp er im en ta l Section
Heating of the NMR tube at 50 °C caused a gradual decrease
of the signals of [Pt(Ph)(acetone-d6)(cod)]+BF4 accompanied
-
Gen er a l Con sid er a tion s. Manipulations of the platinum
complexes were carried out under nitrogen or argon using
standard Schlenk techniques. PtI(Ph)(cod), PtCl2(cod), and
by an increase of signals of uncharacterized decomposition
products. The signals of complexes 1 and 2 were not observed
during heating.

5258 Organometallics, Vol. 21, No. 24, 2002
Suzaki et al.
Rea ction of Ag2O w ith [P tI(P h )(cod )] in Aceton e-d 6.
Equimolar [PtI(Ph)(cod)] and Ag2O were charged to an NMR
sample tube. After addition of acetone-d6 (0.5 mL) to the
mixture, the tube was sealed with a rubber septum. The NMR
tube was heated at 50 °C and subjected to periodic H NMR
measurement.
R ea ct ion of Ag2O w it h [P t I(P h )(cod )] in Tolu en e. A
mixture of [PtI(Ph)(cod)] (103 mg, 0.203 mmol) and Ag2O (50.1
mg, 0.216 mmol) in toluene (1 mL) was heated at 50 °C for 5
days with stirring. [PtI(Ph)(cod)] was dissolved at 50 °C, while
most of the Ag2O remained undissolved. The insoluble black
solid was separated by filtration. Products were obtained by
evaporation of the solvent. The 1H NMR spectrum indicated
formation of 3, whose yield was estimated as 31% by using
1,1,1,2-tetrachloroethane as an internal standard.
tion from hexane and mounted in glass capillary tubes.
Intensities were collected for Lorentz and polarization effects
on a Rigaku AFC-5R automated four-cycle diffractometer by
using Mo KR radiation (λ ) 0.710 69 Å) and the ω-2θ scan
method, and an empirical absorption correction (ψ scan) was
applied. Calculations were carried out using the program
package TEXSAN for Windows. Atomic scattering factors were
obtained from the literature. A full-matrix least-squares
refinement was used for non-hydrogen atoms with anisotropic
thermal parameters. Hydrogen atoms were located by assum-
ing the ideal geometry and included in the structure calcula-
tion without further refinement of the parameters. X-ray data
for complex 1: monoclinic, space group P21 (No. 4), a ) 6.481-
(6) Å, b ) 11.892(5) Å, c ) 10.026(4) Å, â ) 101.51(2)°, V )
757.2(6) Å3, Z ) 2, Dcalcd ) 2.033 g cm-3, F000 ) 460.00, µ(Mo
KR) ) 9.224 mm-1 for monochromated Mo KR radiation (λ )
0.710 69 Å). R (Rw) ) 0.062 (0.058) for 1580 reflections with I
> 3σ(I) among 1825 unique reflections. The absolute structure
was determined by comparison of the Bijvoet pairs.
1
Th er m a l Rea ction of [P t(CH2COMe)(P h )(cod )] (1) in
Aceton e-d 6 or Ben zen e-d 6. In an NMR tube was charged
acetone-d6 (0.6 mL) or a benzene-d6 (0.6 mL) solution of 1 (21.0
mg, 0.048 mmol) under Ar. The Pt complex was dissolved. The
NMR tube was heated in an oil bath (50 °C) and stored when
1
not being actively monitored. H NMR spectra were checked
occasionally.
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research from the Ministry
of Education, Science, Sports, and Culture of J apan.
Rea ction of [P tP h 2(cod )] (2) a n d [P t(CH2COMe)2(cod )]
(3) in Aceton e-d 6 or Ben zen e-d 6. In an NMR tube was
charged an acetone-d6 (0.5 mL) or a benzene-d6 (0.5 mL)
solution of 2 (9.2 mg, 0.020 mmol) and 3 (8.4 mg, 0.020 mmol)
under Ar. The Pt complex was dissolved. The NMR tube was
heated at 50 °C with periodic measurement of the 1H NMR
spectra.
Su p p or tin g In for m a tion Ava ila ble: Text and tables
giving crystallographic data for 1. This material is available
free of charge via the Internet at http://pubs.acs.org.
Cr ysta l Str u ctu r e Deter m in a tion . Crystals of 1 suitable
for an X-ray diffraction study were obtained by recrystalliza-
OM0204991