Chemical properties of mononuclear and dinuclear phenylplatinum(II) hydroxo complexes with cod ligands. Transmetalation of arylboronic acids, coupling of the phenyl ligands, and carbonylation

Article abstract of DOI:10.1021/om060206u

The reaction of bpy with [{Pt(Ph)(cod)}₂(μ-OH)](BF ₄) (1-BF₄; cod = 1,5-cyclooctadiene) in acetone splits a Pt-O bond to yield a mixture of Pt(CH₂COMe)(Ph)(cod) (2) and [Pt(Ph)(bpy)(cod)](BF₄) (3-BF₄), whereas a similar reaction in toluene produces 3-BF₄ and Pt(OH)(Ph)(cod) (4). The complex 4 was obtained in solution and was not isolated as analytically pure crystals because of its gradual disproportionation, giving PtPh₂(cod) (5). The dinuclear complex 1-BF₄ reacts with ArB(OH)₂ (Ar = Ph, C₆H₂F₃-2,4,6) to form 5 and Pt(C ₆H₂F₃-2,4,6)(Ph)(cod) (6), respectively, via aryl group transfer from boron to platinum. The accompanying formation of B(OH)₃ has been confirmed by ¹¹B{¹H} NMR spectroscopy. The reaction of BF₃·Et₂O with 1-BF₄ followed by the addition of NH₄Cl(aq) produces biphenyl and PtCl₂(cod), which takes place possibly via a dinuclear intermediate. The cationic dinuclear complex 1-BF₄ reacts with CO (1 atm) to form benzophenone. Since the reactions of AgBF₄ with Pt-(COPh)(I)(cod) (7) and CO with [Pt(Ph)(THF)(cod)](BF₄) also yield benzophenone, the above carbonylation of 1-BF₄ is considered to involve mononuclear intermediates.

Full text of DOI:10.1021/om060206u

Organometallics 2006, 25, 3251-3258
3251
Chemical Properties of Mononuclear and Dinuclear
Phenylplatinum(II) Hydroxo Complexes with Cod Ligands.
Transmetalation of Arylboronic Acids, Coupling of the Phenyl
Ligands, and Carbonylation
Yuji Suzaki and Kohtaro Osakada*
Chemical Resources Laboratory R1-3, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku,
Yokohama 226-8503, Japan
ReceiVed March 3, 2006
The reaction of bpy with [{Pt(Ph)(cod)}2(µ-OH)](BF4) (1-BF4; cod ) 1,5-cyclooctadiene) in acetone
splits a Pt-O bond to yield a mixture of Pt(CH2COMe)(Ph)(cod) (2) and [Pt(Ph)(bpy)(cod)](BF4) (3-
BF4), whereas a similar reaction in toluene produces 3-BF4 and Pt(OH)(Ph)(cod) (4). The complex 4
was obtained in solution and was not isolated as analytically pure crystals because of its gradual
disproportionation, giving PtPh2(cod) (5). The dinuclear complex 1-BF4 reacts with ArB(OH)2 (Ar )
Ph, C6H2F3-2,4,6) to form 5 and Pt(C6H2F3-2,4,6)(Ph)(cod) (6), respectively, via aryl group transfer from
boron to platinum. The accompanying formation of B(OH)3 has been confirmed by 11B{1H} NMR
spectroscopy. The reaction of BF3‚Et2O with 1-BF4 followed by the addition of NH4Cl(aq) produces
biphenyl and PtCl2(cod), which takes place possibly via a dinuclear intermediate. The cationic dinuclear
complex 1-BF4 reacts with CO (1 atm) to form benzophenone. Since the reactions of AgBF4 with Pt-
(COPh)(I)(cod) (7) and CO with [Pt(Ph)(THF)(cod)](BF4) also yield benzophenone, the above carbo-
nylation of 1-BF4 is considered to involve mononuclear intermediates.
Scheme 1
Introduction
Organoplatinum(II) hydroxo complexes have long been
known, ever since the pioneering report by Bennett et al.1 The
hydroxo ligand of a mononuclear Pt(II) complex was reported
to exhibit a nucleophilic character2 in a way similar to that for
the more common corresponding alkoxoplatinum(II) com-
plexes.3,4 The unique properties of a hydroxo ligand in orga-
noplatinum chemistry is a tendency to coordinate to two metal
centers as a bridging ligand easily.5,6 These dinuclear Pt
complexes are stabilized by the highly basic OH ligand and
flexible Pt-OH-Pt bonding. Recently, we have reported that
the reaction of TBA+OH- (TBA+ ) tetra-n-butylammonium)
with PtI(Ph)(cod) (cod ) 1,5-cyclooctadiene) formed a diphen-
ylplatinum complex via intermolecular phenyl ligand transfer,
as shown in Scheme 1.7 The reaction involves the intermediate
dinuclear platinum complex [{Pt(Ph)(cod)}2(µ-OH)](X-) (1-
X-; X- ) I-, OH-), and the corresponding complex with
another counteranion [{Pt(Ph)(cod)}2(µ-OH)](BF4) (1-BF4) was
obtained by an independent preparation route. The complex
1-X- further reacts with TBA+X- (X- ) OH-, I-) to result in
a smooth transfer of a phenyl ligand between Pt centers,
affording a mononuclear diphenylplatinum complex. In this
paper, we report the chemical properties of the dinuclear
complex 1-BF4 with a bridging hydroxo ligand and of a related
mononuclear complex with a nonbridging hydroxo ligand.
* To whom correspondence should be addressed. E-mail: kosakada@
res.titech.ac.jp.
(1) Bennett, M. A.; Robertson, G. B.; Whimp, P. O.; Yoshida, T. J. Am.
Chem. Soc. 1973, 95, 3028.
(2) Yoshida, T.; Matsuda, T.; Okano, T.; Kitani, T.; Otsuka, S. J. Am.
Chem. Soc. 1979, 101, 2027.
(3) (a) Bennett, M. A.; Yoshida, T. J. Am. Chem. Soc. 1978, 100, 1750.
(b) Bryndza, H. E. Organometallics 1985, 4, 406. (c) Bryndza, H. E.
Organometallics 1985, 4, 1686. (d) Alcock, N. W.; Platt, A. W. G.; Pringle,
P. G. Inorg. Chim. Acta 1987, 128, 215. (e) Alcock, N. W.; Platt, A. W.
G.; Powell, H. H.; Pringle, P. G. J. Organomet. Chem. 1989, 361, 409. (f)
Kim, Y.-J.; Osakada, K.; Takenaka, A.; Yamamoto, A. J. Am. Chem. Soc.
1990, 112, 1096. (g) Osakada, K.; Kim, Y.-J.; Yamamoto, A. J. Organomet.
Chem. 1990, 382, 303. (h) Osakada, K.; Kim, Y.-J.; Tanaka, M.; Ishiguro,
S.; Yamamoto, A. Inorg. Chem. 1991, 30, 197. (i) Kapteijn, G. M.; Dervisi,
A.; Grove, D. M.; Kooijman, H.; Lakin, M. T.; Spek, A. L.; van Koten, G.
J. Am. Chem. Soc. 1995, 117, 10939. (j) Kapteijn, G. M.; Grove, D. M.;
Kooijman, H.; Smeets, W. J. J.; Spek, A. L.; van Koten, G. Inorg. Chem.
1996, 35, 526. (k) Macgregor, S. A.; Neave, G. W. Organometallics 2003,
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891.
(4) Bryndza, H. E.; Tam, W. Chem. ReV. 1988, 88, 1163.
(5) (a) Gilje, J. W.; Roesky, H. W. Chem. ReV. 1994, 94, 895. (b) Jain,
V. K.; Jain, L. Coord. Chem. ReV. 2005, 249, 3075 and references therein.
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Can. J. Chem. 1972, 50, 3694. (b) Li, J. J.; Sharp, P. R. Inorg. Chem. 1994,
33, 183. (c) Li, J. J.; Li, W.; Sharp, P. R. Inorg. Chem. 1996, 35, 604. (d)
Li, J. J.; Li, W.; James, A. J.; Holbert, T.; Sharp, T. P.; Sharp, P. R. Inorg.
Chem. 1999, 38, 1563. (e) Kannan, S.; James, A. J.; Sharp, P. R. Polyhedron
2000, 19, 155.
Results and Discussion
Reaction of Arylboronic Acid with Hydroxoplatinum
Complexes. The complex 1-BF4 reacts with an equimolar
amount of bpy in acetone to produce a mixture of PtPh(CH2-
(7) Suzaki, Y.; Osakada, K. Organometallics 2004, 23, 5081.
10.1021/om060206u CCC: $33.50 © 2006 American Chemical Society
Publication on Web 05/23/2006

3252 Organometallics, Vol. 25, No. 13, 2006
Suzaki and Osakada
Scheme 2
COMe)(cod) (2)8 and [PtPh(bpy)(cod)](BF4) (3-BF4), as shown
in Scheme 2. Since the dissolution of 1-BF4 in acetone does
not form 2, the reaction is induced by the coordination of bpy
to a Pt center of 1-BF4. The complex 2 was also obtained by
the reaction of acetone with PtI(Ph)(cod) in the presence of
Ag2O.8 The reaction of TBA+OH- with PtI(Ph)(cod) in Et2O/
acetone (100/1) produces 2 in 66% yield, as shown in eq 1.
pentacoordinate methylplatinum(II) complex with a cod ligand
and a diimine ligand.9 The Pt1-C1 bond distance is close to
those of reported phenylplatinum(II) complexes with a cod
ligand.8,9
A similar reaction in toluene yields a mixture of 3-BF4 and
Pt(OH)(Ph)(cod) (4). 4 is obtained in toluene (or C6D6) solution
after the removal of 3-BF4 from the reaction mixture by
filtration. The isolation of 4 as analytically pure crystals was
not feasible due to gradual disproportionation to give PtPh2-
(cod) (5) in the solution (vide infra), although Pt(OH)(Me)-
(cod) has been isolated.10 The structure of 4 was confirmed by
the IR and NMR data of the solution, as described below. The
IR spectrum of 4 shows ν(OH) bands at 3677 and 3600 cm-1
.
The peak positions are within the range of those of the OH
ligand of the reported mononuclear organoplatinum hydroxo
complexes (3509-3690 cm-1).1,3,10-12 The bridging OH ligand
of dinuclear platinum complexes including 1-BF4 shows the ν-
(OH) peak at lower wavenumber (3250-3600 cm-1).6,7 The
1H NMR spectrum of 4 exhibits two dCH hydrogen signals of
the cod ligand (δ 5.69, J(PtH) ) 36 Hz and δ 3.76, J(PtH) )
60 Hz). The former signal flanked with a smaller 195Pt-1H
coupling constant is assigned to the CHdCH group trans to
the Ph ligand, which shows a larger trans influence than the
OH ligand.12 The OH hydrogen signal is observed at δ 3.39 in
This reaction as well as the upper reaction of Scheme 2 may
proceed via a mononuclear or dinuclear intermediate with a OH
ligand, which undergoes protonation by acetone, giving a
product with an acetonyl ligand. The complex 3-BF4 has been
isolated and characterized by 1H NMR and ESIMS spectroscopy
1
as well as by elemental analysis. The H NMR spectrum of
3-BF4 shows two dCH hydrogen signals at δ 3.54 and 5.75
(J(195Pt1H) ) 75, 25 Hz) and four signals at δ 8.03, 8.31, 8.58,
and 9.80, assigned to aromatic hydrogens of the bpy ligand. A
complex with another counteranion, 3-PF6, was prepared
separately by treatment of PtI(Ph)(cod) with AgPF6 and then
with bpy and characterized by X-ray crystallography (Figure
1). The complex has trigonal-bipyramidal coordination around
a platinum(II) center which has a Ph ligand and a CdC bond
of a cod ligand at the apical position. The Pt1-C11 and Pt1-
C12 bond distances (2.35(1) and 2.34(1) Å) are elongated
significantly from the Pt1-C7 and Pt1-C8 bond distances
(2.09(1) and 2.07(1) Å), close to the values for another trigonal
1
C6D6, while the H NMR spectrum of 1-BF4 in CDCl3 shows
the signals for the bridging OH ligand only at a low temperature
(δ 4.17, -55 °C).7 Leaving a toluene solution of 4 for 5 days
at room temperature results in the formation of PtPh2(cod) (5;
29%) via intermolecular phenyl ligand transfer, as shown in eq
2. The solutions of PtPhI(L2) and of [PtPh(acetone)(L2)](BF4)
(L2 ) bpy, cod) do not generate the diphenylplatinum complex
via disproportionation.8,13
The complex 1-BF4 reacts with ArB(OH)2 (Ar ) Ph, C6H2F3-
2,4,6) in the presence of H2O ([Pt]:[H2O] ) 1:11) in toluene to
(8) Suzaki, Y.; Yagyu, T.; Yamamura, Y.; Mori, A.; Osakada, K.
Organometallics 2002, 21, 5254.
(9) Bianca, F. D.; Bandoli, G.; Dolmella, A.; Antonaroli, S.; Crociani,
B. Dalton Trans. 2002, 212.
(10) Klein, A.; Klinkhammer, K.-W.; Scheiring, T. J. Organomet. Chem.
1999, 592, 128.
(11) (a) Ros, R.; Michelin, R. A.; Bataillard, R.; Roulet, R. J. Organomet.
Chem. 1978, 161, 75. (b) Arnold, D. P.; Bennett, M. A. J. Organomet.
Chem. 1980, 199, 119. (c) Bennett, M. A.; Rokicki, A. Inorg. Synth. 1989,
25, 100. (d) Bennett, M. A.; Jin, H.; Li, S.; Rendina, L. M.; Willis, A. C.
J. Am. Chem. Soc. 1995, 117, 8335.
(12) Appleton, T. G.; Bennett, M. A. Inorg. Chem. 1978, 17, 738.
(13) (a) Yagyu. T.; Suzaki, Y.; Osakada, K. Organometallics 2002, 21,
2088. (b) Suzaki, Y.; Osakada, K. Bull. Chem. Soc. Jpn. 2004, 77, 139.
Figure 1. ORTEP diagram of [Pt(Ph)(bpy)(cod)](PF6) (3-PF6) with
ellipsoids drawn at the 30% probability level. The PF6 anion and
hydrogen atoms are omitted for clarity. Selected bond distances
(Å): Pt1-N1 ) 2.238(8), Pt1-N2 ) 2.211(8), Pt1-C1 ) 2.038-
(9), Pt1-C7 ) 2.09(1), Pt1-C8 ) 2.07(1), Pt1-C11 ) 2.35(1),
Pt1-C12 ) 2.34(1).

Phenylplatinum(II) Hydroxo Complexes
Organometallics, Vol. 25, No. 13, 2006 3253
Scheme 3
Chart 1
ligand to the boron atom of arylboronic acid, giving a four-
coordinate boron center. The intramolecular activation of the
B-C bond of A would form a new Pt-Ar bond, accompanied
by the elimination of B(OH)3. An alternative concerted mech-
anism, involving the intermediate A′ with a four-membered ring,
forms Pt-C and B-O bonds of the products simultaneously.
The coupling of [PtPh(OH2)(cod)](BF4) accompanied by depro-
tonation may regenerate 1-BF4 (Scheme 3(iii)). Reaction of H2O
with [PtPh(THF)(cod)](BF4) was reported to produce 1-BF4.7
The reaction without the addition of H2O yields the diaryl
complexes in lower yields. Scheme 4 gives a summary of a
pathway of the reaction of ArB(OH)2 with 1-BF4 in the absence
of H2O. ArB(OH)2 reacts with 1-BF4 to generate 4, and it is
likely that the structure of the other complex is the cationic
phenylplatinum complex with arylboronic acid as the ligand
(Scheme 4(i)). The complex 4 is responsible for transmetalation
afford the respective diarylplatinum complexes Pt(Ar)(Ph)(cod)
(5, Ar ) Ph (66%); 6, Ar ) C6H2F3-2,4,6 (83%)) as shown in
eq 3. The accompanying formation of B(OH)3 is confirmed by
1
(Scheme 4(ii)), similarly to Scheme 3. H NMR spectra of the
reaction mixture showed the presence of an intermediate
complex, although it was not characterized unambiguously (see
the Experimental Section). The reaction of PhB(OH)2 with PtI2-
(cod) in the presence of TBA+OH- forms PtPh2(cod) (5) via
the transmetalation of two phenyl groups from boron to
platinum, as shown in eq 5. The addition of TBA+OH- is
11B{1H} NMR spectroscopy. The complex 6 is characterized
by the H NMR spectrum, which exhibits hydrogen signals of
1
the Ph ligand (δ 6.80, 6.98, 7.26) and the C6H2F3-2,4,6 ligand
(δ 6.38). The complex 6 was also prepared from the reaction
of 2,4,6-C6H2F3Li with PtI(Ph)(cod). The reactions without the
addition of H2O produce 5 and 6 in yields lower than those
from eq 3 (38% and 36%, respectively). The reaction of PhB-
(OH)2 with the mononuclear complex 4 prepared in situ forms
the diphenyl complex 5 via the transmetalation of the Ph group
from B to Pt, as shown in eq 4.
indispensable for the formation of 5. A cationic complex without
a OH ligand, [Pt(cod)(THF)2](BF4)2, does not react with PhB-
(OH)2. These results indicate that the hydroxo ligand that bonded
to Pt formed by the reaction of TBA+OH- with PtI2(cod)
induces the transmetalation of PhB(OH)2.14
Pd- and Rh-complex-catalyzed synthetic organic reactions
using arylboronic acids such as Suzuki-Miyaura coupling15 and
1,4-addition of arylboronic acid to R, â-unsaturated carbonyl
(14) Lo´pez, G.; Ruiz, J.; Garc´ıa, G.; Vicente, C.; Mart´ı, J. M.; Hermoso,
J. A.; Vegas, A.; Mart´ınez-Ripoll, M. J. Chem. Soc., Dalton Trans. 1992,
53.
Scheme 3 shows a plausible mechanism to account for
reaction 3. In the presence of water, 1-BF4 is in equilibrium
with 4 and a cationic phenylplatinum complex with an aqua
ligand, [PtPh(OH2)(cod)](BF4), in solution (Scheme 3(i)). The
formed complex 4 reacts with ArB(OH)2 to produce the
diarylplatinum complex and B(OH)3 similarly to reaction 4
(Scheme 3(ii)). The reaction may proceed via the intermediate
A (Chart 1), which is formed by the coordination of the OH
(15) (a) Miyaura, N.; Suzuki, A. Chem. ReV. 1995, 95, 2457. (b) Miyaura,
N. In AdVances in Metal-Organic Chemistry; Liebeskind, L. S., Ed.; JAI:
London, 1998; Vol. 6, p 187. (c) Stanforth, S. P. Tetrahedron 1998, 54,
263. (d) Matos, K.; Soderquist, J. A. J. Org. Chem. 1998, 63, 461. (e)
Tamao, K.; Miyaura, N. In Topics in Current Chemistry; Springer-Verlag:
Berlin, 2002; Vol. 219, p 11. (f) Miyaura, N., Ed. Cross-coupling Reactions,
A Practical Guide; Top. Curr. Chem. Vol. 219; Springer: Berlin, Germany,
2002.

3254 Organometallics, Vol. 25, No. 13, 2006
Suzaki and Osakada
Scheme 4
compounds16 involve the transmetalation of arylboronic acids
with Pd.17 Recent reports on stoichiometric reactions of aryl-
boronic acid with organopalladium revealed details of the
transmetalation reactions. Miyaura reported the reaction of (4-
MeOC6H4)B(OH)2 with [PdPh(µ-OH)(PPh3)]2, affording 4-meth-
oxybiphenyl through diarylpalladium intermediate complexes;18
moreover, the cationic OH-free complex [Pd(dppe)(MeCN)2]-
(BF4)2 (dppe ) 1,2-bis(diphenylphosphino)ethane) also reacts
with PhB(OH)2 in the presence of PPh3 and H2O to form [Pd-
(Ph)(dppe)(PPh3)](BF4) via transmetalation.19 An aryl(iodo)-
palladium complex with phosphine ligands reacts with aryl-
boronic acid in the presence of Ag2O and H2O to produce a
diarylpalladium complex.20 The additives were considered to
generate hydroxopalladium species, which are responsible for
the transmetalation of arylboronic acids. Reports on the reactions
of arylboronic acids with platinum complexes suggested that
the transmetalation of such boronic acids requires the addition
of TBA+F- or Ag2O.21,22 Reaction 4 in this study indicates that
the hydroxoplatinum complex reacts with arylboronic acids
directly to induce the transfer of the aryl group of the arylboronic
acids, even in the absence of such additives. Our recent study
has revealed that the Pt(II) complex with a chelating dehydro-
(arylboronic anhydride) ligand undergoes B-C bond activation
in the absence of a nucleophile.23
complex by the addition of NH4Cl. The reaction of NH4Cl with
1-BF4 produces PtCl(Ph)(cod) via the substitution of the OH
ligand with the Cl ligand, as shown in eq 7. Sharp reported
substitution of the bridging OH ligand without migration of other
ligands; addition of BF3‚Et2O to [Pt(µ-OH)(L2)]2(BF4)2 (L2 )
(C6H4Me-4)NdC(Me)C(Me)dN(C6H4Me-4)) yields [Pt(µ-Cl)-
(L2)]2(BF4)2, whose Cl ligand is derived from the solvent.6e
The reductive elimination of biaryl from mononuclear di-
arylplatinum complexes takes place at high temperatures,24 while
PtPh2(cod) (5) is stable and does not induce the coupling of
phenyl groups at room temperature and 50 °C in solution. The
addition of electron-withdrawing ligands was reported to induce
reductive elimination from dialkyl transition-metal complexes.25
Thus, we conducted the reaction of Lewis acidic BF3 with
complex 5 to obtain further insight into the role of BF3 in the
reactions. The reaction of PtPh2(cod) (5) with BF3‚Et2O and
NH4Cl(aq) forms a mixture of PtCl(Ph)(cod) (74%) and PtCl2-
(cod) (5%), as shown in eq 8. Significant formation of biphenyl
Reaction of BF3‚Et2O with Hydroxoplatinum Complex.
The reaction of BF3‚Et2O with 1-BF4 in toluene-d8 at room
temperature for 12 h, followed by treatment with NH4Cl(aq),
produces a mixture of PtCl2(cod) (54%), Ph-Ph (76%), and
1
benzene (22%), as shown in eq 6. An H NMR measurement
was not observed, indicating that reaction 6 does not involve
the coupling of phenyl ligands from mononuclear diphenyl-
platinum complexes such as 5.
Recently, Kubas and Peters have studied the chemical
properties of cationic phenylplatinum complexes with chelating
diphosphines independently and reported that the cationic
methylplatinum(II) complexes in arene are converted into
dinuclear platinum(II) complexes whose metal centers are
connected with a formally dianionic, bis-π-allylic ligand.26,27
of the reaction mixture before the addition of NH4Cl(aq)
indicates that biphenyl and benzene are released from the
(16) (a) Sakai, M.; Hayashi, H.; Miyaura, N. Organometallics 1997, 16,
4229. (b) Sakuma, S.; Sakai, M.; Itooka, R.; Miyaura, N. J. Org. Chem.
2000, 65, 5951. (c) Yamamoto, Y.; Fujita, M.; Miyaura, N. Synlett 2002,
767. (d) Itooka, R.; Iguchi, Y.; Miyaura, N. J. Org. Chem. 2003, 68, 6000.
(e) Kuriyama, M.; Tomioka, K. Tetrahedron Lett. 2001, 42, 921. (f) Takaya,
Y.; Ogasawara, M.; Hayashi, T.; Sakai, M.; Miyaura, N. J. Am. Chem. Soc.
1998, 120, 5579. (g) Hayashi, T.; Takahashi, M.; Takaya, Y.; Ogasawara,
M. J. Am. Chem. Soc. 2002, 124, 5052.
(17) Osakada, K. Transmetalation. In Current Methods in Inorganic
Chemistry, 3. Fundamentals of Molecular Catalysis; Kurosawa, H., Yama-
moto, A., Eds.; Elsevier Science: Amsterdam, 2003; Chapter 5, pp 233-
291.
(20) Nishihara, Y.; Onodera, H.; Osakada, K. Chem. Commun. 2004,
192. See also: Osakada, K.; Onodera, H.; Nishihara, Y. Organometallics
2005, 24, 190.
(21) Clarke, M. L.; Heydt, M. Organometallics 2005, 24, 6475.
(22) Pantcheva, I.; Nishihara, Y.; Osakada, K. Organometallics 2005,
24, 3815.
(23) Pantcheva, I.; Osakada, K. Organometallics 2006, 25, 1735.
(24) (a) Braterman, P. S.; Cross, R. J.; Young, G. B. J. Chem. Soc.,
Dalton Trans. 1977, 1892. (b) Shekhar, S.; Hartwig, J. F. J. Am. Chem.
Soc. 2004, 126, 13016.
(25) Yamamoto, T.; Yamamoto, A.; Ikeda, S. J. Am. Chem. Soc. 1971,
93, 3350.
(18) Miyaura, N. J. Organomet. Chem. 2002, 653, 54.
(19) Nishikata, T.; Yamamoto, Y.; Miyaura, N. Organometallics 2004,
23, 4317.
(26) Konze, W. V.; Scott. B. L.; Kubas, G. J. J. Am. Chem. Soc. 2002,
124, 12550.

Phenylplatinum(II) Hydroxo Complexes
Organometallics, Vol. 25, No. 13, 2006 3255
Scheme 5
Scheme 6
of PtCl(COPh)(cod).31 Figure 2 depicts the molecular structure
of 7 obtained by X-ray crystallography. The bond distances of
The bridging biaryl ligands are liberated upon treatment of the
dinuclear complex with I2 or HCl.26 The formation of the
dinuclear Pt complexes may take place via a bimolecular
coupling or initial disproportionation of a monophenyl platinum
complex, which was discussed by Kubas and Peters. Scheme 5
shows a plausible mechanism proposed to explain reaction 6
on the basis of these previous results. The reaction of BF3‚Et2O
with 1-BF4 eliminates the bridging OH ligand to form the
cationic mononuclear platinum(II) complex [PtPh(OEt2)(cod)]+-
(BF3X)- (X ) F, OH). Because the initially formed mono-
nuclear complex has a labile OEt2 ligand, it undergoes facile
coupling of two complex molecules accompanied by C-C bond
formation to form the complex B with a bridging biphenyl
ligand. B reacts with NH4Cl to release biphenyl and PtCl2(cod).
NMR measurement of the reaction mixture did not provide
evidence for structures of the proposed intermediate B, possibly
due to its low solubility.
Figure 2. ORTEP diagram of complex 7 with ellipsoids drawn at
the 50% probability level. Selected bond distances (Å): Pt1-I1 )
2.6149(3), Pt1-C1 ) 2.032(4), Pt1-C8 ) 2.329(4), Pt1-C9 )
2.348(4), Pt1-C12 ) 2.156(4), Pt1-C13 ) 2.181(4), C1-O1 )
1.203(5).
Pt1-C8 and Pt1-C9 (2.329(4), 2.348(4) Å) were significantly
longer than those of Pt1-C12 and Pt1-C13 (2.156(4), 2.181-
(4) Å) due to the trans influence of the aroyl ligand being greater
than that of the iodo ligand. The reaction of AgBF4 with 7 in
THF affords benzophenone in 40% yield. The cationic phenyl-
platinum complex [PtPh(THF)(cod)](BF4), formed in situ by
the reaction of AgBF4 and PtI(Ph)(cod), also reacts with CO (1
atm) to give benzophenone in 40% yield.
Scheme 7 shows a pathway of carbonylation; [PtPh(THF)-
(cod)](BF4) undergoes the migratory insertion of CO into the
Reaction of CO with Hydroxoplatinum Complexes. The
palladium-complex-catalyzed carbonylation of aryl halides under
a CO atmosphere provides a means of synthesizing ketone and
esters.28 The complex 1-BF4 forms benzophenone under a CO
atmosphere (1 atm), as shown in eq 9. The carbonylation of
Scheme 7
mononuclear diorganopalladium and platinum complexes as well
as a dinuclear complex with a bridging aryl ligand with a long
tether was reported to produce the corresponding ketones.29,30
Scheme 6 shows a summary of the reactions of related
mononuclear phenylplatinum complexes leading to carbonyla-
tion. The reaction of PtI(Ph)(cod) with CO (1 atm) causes the
insertion of CO into the Pt-C bond to form PtI(COPh)(cod)
(7), which has been characterized by NMR and IR spectroscopy
as well as by comparison of the NMR and IR data with those
Pt-Ph bond to form an intermediate cationic complex with a
benzoyl ligand, D. D is in a rapid equilibrium with [PtPh(CO)-
(cod)](BF4) (C) via a reversible deinsertion and insertion of CO
(Scheme 8(i)). Intermolecular phenyl ligand transfer from C to
D in the reaction mixture forms benzophenone, as shown in
Scheme 8(ii).
Reaction 9, which forms benzophenone from the dinuclear
complex 1-BF4, is explained as follows. 1-BF4 reacts with CO
to form a mixture of PtPh(OH)(cod) (4) and [PtPh(CO)(cod)]-
(BF4). The latter undergoes migratory insertion of CO into the
(27) Thomas, J. C.; Peters, J. C. J. Am. Chem. Soc. 2003, 125, 8870.
(28) Negishi, E., de Meijere, A., Eds. Handbook of Organopalladium
Chemistry for Organic Synthesis; Wiley: New York, 2002.
(29) (a) Fryzuk, M. D.; Clentsmith, G. K. B.; Rettig, S. J. J. Chem. Soc.,
Dalton Trans. 1998, 2007. (b) Chen, J.-T.; Yeh, Y.-S.; Yang, C.-S.; Tsai,
F.-Y.; Huang, G.-L.; Shu, B.-C.; Huang, T.-M.; Chen, Y.-S.; Lee, G.-H.;
Cheng, M.-C.; Wang, C.-C.; Wang, Y. Organometallics 1994, 13, 4804.
(30) Suzaki, Y.; Osakada, K. Organometallics 2003, 22, 2193.
(31) (a) Anderson, G. K.; Clark, H. C.; Davies, J. A. Inorg. Chem. 1981,
20, 1636. (b) Anderson, G. K.; Lumetta, G. J. Organometallics 1985, 4,
1542.

3256 Organometallics, Vol. 25, No. 13, 2006
Suzaki and Osakada
Scheme 8
8, 5, 1 Hz), 8.31 (ddd, 2H, H5 bpy, J(HH) ) 8, 8, 2 Hz), 8.58
(ddd, 2H, H6 bpy, J(HH) ) 8, 1, 1 Hz), 9.80 (ddd, 2H, H3 bpy,
J(HH) ) 5, 2, 1 Hz, J(HH) ) ca. 15 Hz). ESIMS (CH3CN): m/z
536 [M - BF4]+. Anal. Calcd for C24H25F4N2BPt + H2O: C, 44.94;
H, 4.24; N, 4.37. Found: C, 44.89; H, 4.38; N, 4.36.
Preparation of [PtPh(bpy)(cod)](PF6) (3-PF6). To a THF
solution of PtI(Ph)(cod) (254 mg, 0.50 mmol) was added AgPF6
(135 mg, 0.53 mmol) to induce separation of AgI. After 10 min of
stirring at room temperature, bpy (79 mg, 0.51 mmol) was added
to the reaction mixture and the mixture was stirred for a further 10
min. After removal of insoluble AgI, the solvent was evaporated
to dryness and the solid residue was extracted with CH2Cl2. The
extract was concentrated to ca. 3 mL, and subsequent addition of
Et2O (100 mL) to the product caused separation of a off-white solid,
which was washed with Et2O and dried in vacuo to give 3-PF6
(250 mg, 0.37 mmol, 74%). 1H NMR (300 MHz, acetone-d6, room
temperature): δ 2.33-2.53 (4H, CH2), 2.68-2.72 (2H, CH2 cod),
2.96-3.01 (2H, CH2), 3.54 (m, 2H, CH cod (basal), J(PtC) ) 76
Hz), 5.75 (m, 2H, CH cod (apical), J(PtH) ) 26 Hz), 6.71-6.75
(3H, meta Ph, para Ph), 7.14 (m, 2H, ortho Ph, J(PtH) ) 39 Hz),
8.03 (ddd, 2H, H4 bpy, J(HH) ) 7, 5, 1 Hz), 8.32 (dd, 2H, H5
bpy, J(HH) ) 8, 8 Hz), 8.57 (d, 2H, H6 bpy, J(HH) ) 8 Hz), 9.80
(d, 2H, H3 bpy, J(HH) ) 5 Hz, J(PtH) ) ca. 14 Hz). 13C{1H}
NMR (100 MHz, acetone-d6, room temperature): δ 27.9 (CH2,
J(PtC) ) 26 Hz), 35.0 (CH2, J(PtC) ) 35 Hz), 60.7 (CH cod
(apical), J(PtC) ) 529 Hz), 121.2 (CH cod (basal), J(PtC) ) 30
Hz), 124.4 (C4 bpy), 124.9 (para Ph), 128.9 (meta Ph, J(PtC) )
46 Hz), 129.0 (C5 bpy), 134.4 (ortho Ph), 136.9 (ipso Ph), 141.1
(C6 bpy), 152.5 (C3 bpy, J(PtC) ) 31 Hz), 153.0 (C2 bpy). Anal.
Calcd for C24H25F6N2PPt: C, 42.30; H, 3.70; N, 4.11. Found: C,
41.93; H, 3.75; N, 4.07.
Pt-Ph bond to form [Pt(COPh)(CO)(cod)](BF4). The intermo-
lecular transmetalation of a phenyl ligand between 4 (or [PtPh-
(CO)(cod)](BF4)) with [Pt(COPh)(CO)(cod)](BF4) forms the
product via intermediate PtPh(COPh)(cod). The mononuclear
complexes in Schemes 6 and 7 form benzophenone in yields
similar to that of the reaction of CO with 1-BF4 and are
considered to be the intermediates of carbonylation of the
dinuclear complexes.
In conclusion, we have demonstrated the reactions of the
hydroxoplatinum complex [{Pt(Ph)(cod)}2(µ-OH)](BF4) (1-BF4)
as well as the mononuclear phenylplatinum hydroxo complex.
Transmetalation of arylboronic acids yields symmetrical or
unsymmetrical diarylplatinum complexes under mild conditions.
Coupling of the phenyl ligands of 1-BF4 caused by addition of
BF3‚Et2O is considered to involve a dinuclear intermediate,
while carbonylation of 1-BF4, giving PhCOPh, takes place via
insertion of CO into a Pt-C bond and successive intermolecular
transmetalation of the phenyl ligand.
Reaction of bpy with 1-BF4 in C6D6. To a C6D6 (2.0 mL)
suspension of 1-BF4 (65 mg, 0.075 mmol) was added bpy (11 mg,
0.070 mmol). The mixture was stirred for 20 min at room
temperature. The solid that was not soluble in C6D6 was removed
by filtration. The filtrate contained Pt(OH)(Ph)(cod) (4), which was
characterized by 1H NMR and IR spectroscopy of the solution. 1H
NMR (300 MHz, C6D6, room temperature): δ 1.44-1.59 (4H,
CH2), 1.74-1.93 (4H, CH2), 3.39 (br, 1H, OH), 3.76 (m, 2H, CH
cod (trans to OH), J(PtH) ) 60 Hz), 5.69 (m, 2H, CH cod (trans
to Ph), J(PtH) ) 36 Hz), 7.04 (m, 1H, para Ph), 7.12-7.18* (2H,
meta Ph), 7.45 (m, 2H, ortho Ph, J(PtH) ) 54 Hz). The peak with
an asterisk is overlapped significantly with the signal of C6D5H.
13C{1H} NMR (100 MHz, C6D6, room temperature): δ 27.3 (CH2),
31.8 (CH2), 79.5 (br, CH cod, trans to OH), J(PtC) ) 200 Hz),
115.0 (br, CH cod (trans to Ph), J(PtC) ) 60 Hz), 125.2 (br, para
Ph), 128.8 (meta Ph), 134.9 (ortho Ph), 147.2 (br, ipso Ph). The
13C{1H} NMR spectrum of 4 was obtained as a mixture with PtPh2-
(cod) (5), formed by disproportionation of 4 (eq 4). IR (C6D6): ν-
Experimental Section
General Considerations. Manipulations of the complexes were
carried out under nitrogen or argon using standard Schlenk
techniques. Dried solvents were purchased from Kanto Chemical
Co., Inc. TBA+OH- (37% in methanol) was purchased from Tokyo
Kasei Kogyo Co., Ltd. 1-BF4, PtX2(cod) (X ) Cl, I, Ph), and PtI-
(Ph)(cod) were prepared by literature methods.7,32 Pt(C6H2F3-2,4,6)-
(Ph)(cod) (6) was prepared according to the procedures reported
for similar complexes.24b Other chemicals were commercially
available. NMR spectra (1H, 11B{1H}, 13C{1H}, 19F{1H}) were
recorded on Varian MERCURY300 and JEOL EX-400 spectrom-
eters. The chemical shifts were referenced with C6D5H (δ 7.15) or
1
CHCl3 (δ 7.24) for H and CDCl3 (δ 77.0) for 13C. IR absorption
spectra were recorded on Shimadzu FT/IR-8100 spectrometers.
Electrospray ionization mass spectrometry (ESIMS) was recorded
on a ThermoQuest Finnigan LCQ Duo. Elemental analyses were
carried out with a Yanaco MT-5 CHN autorecorder.
(OH); 3600, 3677 cm-1
.
Reaction of PtI(Ph)(cod) with TBA+OH- in Et2O/Acetone.
To a Et2O/acetone (100 mL/1 mL) solution of PtI(Ph)(cod) (152
mg, 0.30 mmol) was added TBA+OH- (0.40 mmol) in methanol.
The mixture was stirred for 1 h at room temperature. The resulted
solid was removed by filtration. Evaporation of solvent gave a crude
product that was dissolved in Et2O (10 mL). This solution was
washed with H2O (10 mL, 5 times), dried over MgSO4, and filtered.
Evaporation of the solvent under reduced pressure gave 2 as a white
solid (87 mg, 0.20 mmol, 66%).
Reaction of bpy with 1-BF4 in Acetone. To an acetone (2.0
mL) suspension of 1-BF4 (65 mg, 0.075 mmol) was added bpy
(12 mg, 0.077 mmol). The mixture was stirred for 20 min at room
temperature. Addition of hexane (20 mL) to the reaction mixture
caused separation of a yellow solid, which was collected by filtration
to give 3-BF4 (44 mg, 0.071 mmol, 95%). Evaporation of the filtrate
formed a pale yellow solid of Pt(CH2COMe)(Ph)(cod) (2; 0.033
1
mmol, 44%), which was characterized by comparison of the H
Reaction of 4 in Toluene. A solution of Pt(OH)(Ph)(cod) (4)
was prepared from the reaction of bpy (12 mg, 0.077 mmol) with
1-BF4 (65 mg, 0.075 mmol) for 20 min at room temperature. [PtPh-
(bpy)(cod)](BF4) (3-BF4; 46 mg, 0.074 mmol, 99%) was separated
as a colorless solid from the solution and removed by filtration.
The filtrate that contained 4 as an exclusive Pt complex was stirred
for 5 days at room temperature. Evaporation of the solvent gave a
solid containing PtPh2(cod) (5; 0.011 mmol, 29%). The yield was
NMR spectrum with authentic samples. Data for 3-BF4 are as
follows. H NMR (300 MHz, acetone-d6, room temperature): δ
2.32-2.82 (6H, CH2), 2.95-3.05 (2H, CH2), 3.54 (m, 2H, CH cod
(basal), J(PtH) ) 75 Hz), 5.75 (m, 2H, CH cod (apical, trans to
C), J(PtH) ) 25 Hz), 6.71-6.76 (3H, meta Ph, para Ph), 7.14 (m,
2H, ortho Ph, J(HH) ) 41 Hz), 8.03 (ddd, 2H, H4 bpy, J(HH) )
1
(32) Clark, H. C.; Manzer, L. E. J. Organomet. Chem. 1973, 59, 411.

Phenylplatinum(II) Hydroxo Complexes
Organometallics, Vol. 25, No. 13, 2006 3257
1
determined by integration of the H NMR signal using trichloro-
ethylene as an internal standard.
temperature. The solution was partitioned by addition of saturated
NH4Cl(aq) and toluene (2 mL) to the solution. The organic extract
was washed with H2O (4 mL) and dried over MgSO4. Evaporation
of solvent gave a mixture of PtPh2(cod) (5; 0.051 mmol, 51%),
PtCl(Ph)(cod) (0.014 mmol, 14%), and PtCl2(cod) (0.007 mmol,
Reaction of ArB(OH)2 (Ar ) Ph, C6H2F3-2,4,6) with 1-BF4.
To a toluene (2.0 mL) suspension of 1-BF4 (43 mg, 0.05 mmol)
was added H2O (20 µL, 0.11 mmol) and (C6H2F3-2,4,6)ArB(OH)2
(18 mg, 0.10 mmol). The mixture was stirred for 1 h at room
temperature. Evaporation of the solvent gave a mixture containing
Pt(C6H2F3-2,4,6)(Ph)(cod) (6; 0.083 mmol, 83%), which was
1
7%). These products were characterized on the basis of H NMR
spectroscopy. The yields were determined by integration of the 1H
NMR signal using diphenylethane as an internal standard. A similar
reaction in the absence of TBA+OH- recovered unreacted PtI2-
(cod).
1
extracted by CDCl3 and characterized on the basis of H NMR
spectroscopy using diphenylethane as an internal standard. The solid
that was not dissolved in CDCl3 contained B(OH)3, which was
identified by its 11B{1H} NMR spectrum in acetone-d6 (BF3‚Et2O,
internal standard). A similar reaction of PhB(OH)2 (13 mg, 0.10
mmol) with 1-BF4 (43 mg, 0.05 mmol) yielded 5 (0.066 mmol,
66%).
Reaction of PhB(OH)2 with [Pt(cod)(THF)2](BF4)2. To a THF
(1.0 mL) suspension of PtI2(cod) (56 mg, 0.10 mmol) was added
a THF (1.0 mL) solution of AgBF4 (40 mg, 0.21 mmol). After the
mixture was stirred for 1 h at room temperature, the resulting AgI
was removed by filtration. After addition of PhB(OH)2 (24 mg,
0.20 mmol) to the filtrate, the reaction mixture was stirred for 12
h at room temperature. Saturated NH4Cl(aq) (2 mL) was added to
the solution to convert the cationic or coordinatively unsaturated
Pt complexes into the corresponding chloroplatinum complexes,
and the products were extracted. The extract was washed with water
(10 mL) and dried over MgSO4. The absence of PtPh2(cod) (5)
The reactions in the absence of water yielded Pt(C6H2F3-2,4,6)-
(Ph)(cod) (6) (36%) and PtPh2(cod) (38%) (5), respectively.
NMR measurement of the reaction mixture of PhB(OH)2 (6.1
mg, 0.05 mmol) with 1-BF4 (22 mg, 0.025 mmol) was conducted
in toluene-d8 (1.0 mL). The 11B{1H} NMR spectrum after 1 h at
room temperature showed signals at δ 28 (broad) and -0.8. The
signals are assigned to PhB(OH)2 and BF4, respectively. 1H NMR
spectrum of the mixture showed signals due to 1-BF4 and PtPh2-
(cod) (δ 4.80) and minor peaks at δ 6.21, 3.71, and 3.43, which
are assigned to two signals of CH cod hydrogen and one BOH
hydrogen of an intermediate complex.
1
and PtPh(Cl)(cod) in the reaction mixture was confirmed by H
NMR spectroscopy.
Reaction of 1-BF4 and BF3‚Et2O. To a toluene-d8 (1.0 mL)
suspension of 1-BF4 (43 mg, 0.05 mmol) was added BF3‚Et2O (15
µL, 0.12 mmol). Stirring the mixture for 12 h at room temperature
caused separation of a yellow solid from the solution. The solution
contained small amounts of biphenyl (<0.003 mmol, <6%) and
benzene (<0.006 mmol, <6%), which were characterized by a 1H
NMR spectrum. The yields were determined by integration of the
1H NMR signal using trichloroethylene as an internal standard.
Saturated NH4Cl(aq) (1 mL) was added to the mixture, which was
stirred for a further 10 min at room temperature. 1H NMR spectrum
indicated formation of biphenyl (0.038 mmol, 76%), benzene (0.022
mmol, 22%), PtCl2(cod) (0.054 mmol, 54%), and cod (0.006 mmol,
12%).
Preparation of Pt(C6H2F3-2,4,6)(Ph)(cod) (6). To an Et2O (2.0
mL) solution of (C6H2F3-2,4,6)Br (420 mg, 2.0 mmol) was added
nBuLi (1.56 M hexane solution, 1.3 mL, 2.0 mmol) at -40 °C.
After the mixture was stirred for 1 h at -40 °C, PtI(Ph)(cod) (660
mg, 1.3 mmol) was added at that temperature. The reaction mixture
was stirred for a further 1 h and then gradually warmed to 0 °C.
After quenching of the reaction by saturated NH4Cl(aq) (30 mL),
products were extracted with Et2O (20 mL). The combined organic
extracts were washed with water (50 mL) and dried over MgSO4.
Removal of the solvent and washing the remaining solid with cold
hexane (10 mL, 2 times) yielded Pt(C6H2F3-2,4,6)(Ph)(cod) (6; 386
mg, 0.75 mmol, 58%). 1H NMR (300 MHz, CDCl3, room
temperature): δ 2.42-2.58 (8H, CH2), 5.03 (m, 2H, CH cod, J(PtH)
) 47 Hz), 5.27 (m, 2H, CH cod, J(PtH) ) 38 Hz), 6.38 (m, 2H,
C6H2F3), 6.80 (m, 1H, para Ph), 6.98 (m, 2H, meta Ph), 7.26 (m,
2H, ortho Ph, J(PtH) ) 64 Hz). 13C{1H} NMR (75.5 MHz, CDCl3,
room temperature): δ 29.6 (CH2), 30.3 (CH2, J(PtC) ) 10 Hz),
99.2 (ddd, meta C6H2F3, J(FC) ) 33.4, 24.2, 4.0 Hz), 102.7 (CH,
J(PtC) ) 85 Hz), 105.8 (CH, J(PtC) ) 39 Hz), 123.2 (para Ph,
J(PtC) ) 11 Hz), 127.9 (meta Ph, J(PtC) ) 68 Hz), 134.7 (ortho
Ph, J(PtC) ) 35 Hz), 149.2 (ipso Ph), 159.0 (m, C6H2F3), 162.2
(m, C6H2F3), 165.3 (dd, C6H2F3, J(FC) ) 25.4, 15.0 Hz). 19F{1H}
NMR (282 MHz, CDCl3, room temperature): δ -118.5 (m, 1F),
-92.3 (m, 2F, J(PtF) ) 367 Hz). Anal. Calcd for C20H19F3Pt: C,
46.97; H, 3.74; F, 11.14. Found: C, 46.66; H, 3.51; F, 10.81.
Reaction of PhB(OH)2 with 4. To a C6D6 (1.0 mL) suspension
of 1-BF4 (86 mg, 0.1 mmol) was added bpy (15 mg, 0.1 mmol).
The mixture was stirred for 20 min at room temperature. The 3-BF4
that formed was separated from the solution and removed by
filtration. The combined filtrate and washings of 3-BF4 with C6D6
contained 4 as an almost exclusive Pt complex. PhB(OH)2 (6.1 mg,
0.05 mmol) and 1,2-diphenylethane (7.4 mg, 0.042 mmol) (internal
standard for NMR) were added to the solution. The 1H NMR spectra
were recorded at room temperature occasionally. The solution after
1.5 h contained PtPh2(cod) (5; 0.036 mmol, 72%) and Pt(Ph)(OH)-
(cod) (4; 0.012 mmol, 24%). The solid which separated from C6D6
was characterized by its 11B{1H} NMR spectrum in acetone-d6.
Reaction of BF3‚Et2O with 5. To a toluene (1.0 mL) solution
of 5 (46 mg, 0.1 mmol) was added BF3‚Et2O (13 µL, 0.10 mmol).
After the mixture was stirred for 6 h at room temperature, saturated
NH4Cl(aq) (2 mL) was added to the mixture. The products were
extracted with THF (2 mL, 3 times), and the combined organic
phase was washed with water (5 mL, 2 times), dried over MgSO4,
and filtered. Evaporation of the solvent gave solids containing PtCl-
(Ph)(cod) (0.074 mmol, 74%), PtCl2(cod) (0.005 mmol, 5%), and
1
biphenyl (0.003 mmol, 3%), which were characterized by a H
NMR spectrum in CDCl3. The yields were determined by integra-
1
tion of the H NMR signal using trichloroethylene as an internal
standard.
Reaction of NH4Cl with 1-BF4. To a THF (2.0 mL) suspension
of 1-BF4 (87 mg, 0.10 mmol) was added 1.0 M NH4Cl(aq) (1.0
mmol, 1 mL). The mixture was stirred for 5 h at room temperature.
The product was extracted with Et2O, and the organic extract was
washed with water and dried over MgSO4. Evaporation of the
solution gave a solid containing PtCl(Ph)(cod) (0.16 mmol, 80%),
1
which was characterized by a H NMR spectrum. The yield was
1
determined by integration of the H NMR signal using diphenyl-
methane as internal standard.
Carbonylation of 1-BF4. To a CH2Cl2 (2.0 mL) solution of
1-BF4 (89 mg, 0.10 mmol) in a Schlenk flask was introduced CO
at 1 atm. The solution was stirred for 13 h at room temperature.
Addition of Et2O to the solution caused separation of a solid, which
was removed by filtration. Evaporation of the solution gave a solid
containing PhCOPh (0.043 mmol, 43%), which was characterized
by 1H and 13C{1H} NMR spectroscopy. The yield was determined
by integration of the 1H NMR signal using 1,1,2,2-tetrachloroethane
as an internal standard.
Reaction of PhB(OH)2 and TBA+OH- with PtI2(cod). To a
toluene (2.0 mL) suspension of PtI2(cod) (56 mg, 0.10 mmol) and
PhB(OH)2 (24 mg, 0.20 mmol) was added TBA+OH- (0.20 mmol)
in methanol (140 mg). The mixture was stirred for 4 h at room

3258 Organometallics, Vol. 25, No. 13, 2006
Suzaki and Osakada
Table 1. Crystal Data and Details of Structure Refinement
of 3-PF6 and 7
Carbonylation of PtI(Ph)(cod). To a CH2Cl2 (15 mL) solution
of PtI(Ph)(cod) (766 mg, 1.5 mmol) in a Schlenk flask was
introduced CO at 1 atm. The solution was stirred for 15 h at room
temperature. Evaporation of the solution gave a yellow solid.
Recrystallization from CH2Cl2/Et2O (5 mL/50 mL) gave PtI(COPh)-
3-PF6
7
formula
mol wt
cryst syst
space group
a/Å
C24H25F6N2PPt
681.53
C15H17IOPt
535.29
1
(cod) (7; 607 mg, 1.1 mmol, 73%). H NMR (300 MHz, CDCl3,
orthorhombic
Pbca (No. 61)
17.465(7)
15.145(7)
17.870(8)
-
monoclinic
P21/n (No. 14)
8.887(1)
12.414(1)
13.254(2)
92.967(1)
1460.3(3)
4
room temperature): δ 2.09-2.57 (8H, CH2), 4.68 (m, 2H, CH cod
(trans to I), J(PtH) ) 77 Hz), 5.87 (m, 2H, CH cod (trans to C),
J(PtH) ) 22 Hz), 7.40 (m, 2H, meta Ph), 7.44 (m, 1H, para Ph),
8.00 (m, 2H, ortho Ph). 13C{1H} NMR (100 MHz, CDCl3, room
temperature): δ 28.1 (CH2, J(PtC) ) 24 Hz), 31.6 (CH2, J(PtC) )
25 Hz), 91.4 (CH cod, J(PtC) ) 195 Hz), 117.8 (CH cod), 128.1,
b/Å
c/Å
â/deg
V/Å3
4727(4)
8
Z
130.3, 132.1, 145.7, 208.7 (CdO). IR (KBr): ν(CdO); 1640 cm-1
.
F(000)
D
2640.00
1.915
984.00
2.435
calcd/ g cm-3
Anal. Calcd for C15H17OIPt: C, 33.66; H, 3.20. Found: C, 33.39;
H, 3.16.
cryst size/mm
0.40 × 0.20 × 0.10
0.40 × 0.40 × 0.20
no. of unique rflns
no. of used rflns
(I g 1.0σ(I))
no. of variables
R (I g 1.0 σ(I))
5384
3269
PtI(COPh)(cod) (7) was stable in the solid state. No decarbo-
nylation was observed, even after the solid was kept under reduced
pressure (3 × 10-4 atm) at room temperature for 6 h.
Reaction of AgBF4 with PtI(COPh)(cod) (7). To a THF (2.0
mL) solution of 7 (54 mg, 0.10 mmol) was added AgBF4 (20 mg,
0.10 mmol). The mixture was stirred for 1 h at room temperature
followed by addition of saturated NH4Cl(aq) (4 mL). The product
was extracted with Et2O, and the combined organic extract was
dried over MgSO4. The solvent was removed by evaporation to
give a mixture containing PhCOPh (0.020 mmol, 40%), which was
4983
3229
332
180
0.042
0.076
1.06
0.027
0.041
1.02
R
w (I g 1.0 σ(I))
goodness of fit
collected. A sweep of data was done using ω scans from -110.0
to 70.0° in 0.5° steps, at ø ) 45.0° and φ ) 0.0°. Calculations
were carried out by using a program package CrystalStructure for
Windows.33 The structure was solved by direct methods and
expanded using Fourier techniques. Crystal data and detailed results
of refinement are summarized in Table 1.
1
characterized on the basis of H NMR spectroscopy. The yields
were determined by integration of the 1H NMR signal using
trichloroethylene as an internal standard. A similar reaction in
acetone gave PhCOPh (0.019 mmol, 38%) also.
Acknowledgment. This work was supported by Grants-in-
Aid for Scientific Research from the Ministry of Education,
Science, Sports, and Culture of Japan and by the 21st Century
COE Program “Creation of Molecular Diversity and Develop-
ment of Functionalities”. Y.S. acknowledges a scholarship from
the Japan Society for the Promotion of Science. We are grateful
to Professor Munetaka Akita of our institute for ESIMS
measurements.
Carbonylation of [PtPh(THF)(cod)](BF4). To a THF (2.0 mL)
solution of PtI(Ph)(cod) (101 mg, 0.2 mmol) was added AgBF4
(38 mg, 0.2 mmol) in THF (2.0 mL). The mixture was stirred for
10 min at room temperature followed by removal of the formed
AgI by filtration. CO (1 atm) was introduced to the solution, which
was stirred for another 2 h at room temperature. Saturated NH4-
Cl(aq) (5 mL) was added to the solution. The organic extract was
washed with water (5 mL) and dried over MgSO4. The solvent
was removed by evaporation to give a mixture containing PhCOPh
(0.039 mmol, 39%) and free cod (trace), which were characterized
on the basis of H NMR spectroscopy. The yield was determined
by integration of the 1H NMR signal using trichloroethylene as an
internal standard.
Crystal Structure Determination. Crystals of 3-PF6 and 7
suitable for X-ray diffraction study were obtained by recrystalli-
zation from acetone/Et2O and CH2Cl2/Et2O, respectively, and
mounted in a glass capillary tube. The data were collected to a
maximum 2θ value of 55°. A total of 720 oscillation images were
Supporting Information Available: Crystallographic data of
3-PF6 and 7 as CIF files, and figures giving the 11B{1H} NMR
spectrum obtained after reaction 3 and IR, 1H NMR, and 13C{1H}
NMR spectra of Pt(OH)(Ph)(cod) (4). This material is available
free of charge via the Internet at http://pubs.acs.org.
1
OM060206U
(33) Crystal Structure: Crystal Analysis Package; Rigaku and Rigaku/
MSC, 2000-2006.