Four-, five-, and six-membered silaplatinacycles obtained from the reaction of an arylallene with Pt(SiHPh2)2(PMe3)2

Article abstract of DOI:10.1021/om010266u

The reaction of (4-fluorophenyl)allene with Pt(SiHPh₂)₂(PMe₃)₂ gives 2-sila-1-platinacyclobutane, 2,5-disila-1-platinacyclopentane, or 4-sila-1-platinacyclohexane, depending on the reaction conditions. All these

Full text of DOI:10.1021/om010266u

Organometallics 2001, 20, 4451-4453
4451
F ou r -, F ive-, a n d Six-Mem ber ed Sila p la tin a cycles
Obta in ed fr om th e Rea ction of a n Ar yla llen e w ith
P t(SiHP h 2)2(P Me3)2
Makoto Tanabe, Hideto Yamazawa, and Kohtaro Osakada*
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226-8503, J apan
Received April 2, 2001
Summary: The reaction of (4-fluorophenyl)allene with
Pt(SiHPh2)2(PMe3)2 gives 2-sila-1-platinacyclobutane,
2,5-disila-1-platinacyclopentane, or 4-sila-1-platinacy-
clohexane, depending on the reaction conditions. All
these complexes were characterized by X-ray crystal-
lography and NMR spectroscopy.
2,5-Disila-1-metallacyclopentanes1-10 have attracted
attention owing to their unique chemical properties and
the important roles they play as an intermediate of
transition metal complex catalyzed hydrosilylation and
bis-silylation of unsaturated compounds.3,8 Most of these
complexes were prepared by the oxidative addition of
two Si-H bonds of 1,2-bis(silyl)alkanes, HSiR2CH2CH2-
SiR2H, to low-valent transition metal complexes. On the
other hand, the reactions of alkene and alkyne with
M(SiX3)2(PR3)2 (M ) Pd, Pt; X ) Me, Ph, F) lead to the
formation of their 1,2-disilylation products,11,12 which
are closely related to the mechanism of bis-silylation of
alkene, allene, and alkyne catalyzed by transition metal
complexes.13-15 A similar reaction of alkene or allene
F igu r e 1. ORTEP drawing of 1 at the 50% ellipsoidal
level. Selected bond distances (Å) and angles (deg):
Pt-P1 2.277(3), Pt-P2 2.349(4), Pt-Si1 2.367(3), Pt-C1
2.14(1), Si1-C2 1.87(1), C2-C3 1.31(2), C3-C4 1.48(2);
P1-Pt-P2 99.4(1), P1-Pt-Si1 100.7(1), P1-Pt-C1 168.8-
(3), P2-Pt-Si1 159.6(1), P2-Pt-C1 91.7(3), Si1-Pt-C1
68.1(3), Pt-Si1-C2 85.3(4), Pt-C1-C2 103.2(7), Si1-C2-
C1 95.8(8), Si1-C2-C3 141(1), C1-C2-C3 120(1),
C2-C3-C4 128(1).
(1) Eaborn, C.; Metham, T. N.; Pidcock, A. J . Organomet. Chem.
1973, 63, 107.
(2) Vancea, L.; Graham, W. A. G. Inorg. Chem. 1974, 13, 511.
(3) Corriu, R. J . P.; Moreau, J . J . E.; Pataud-Sat, M. J . Organomet.
Chem. 1982, 228, 301. Corriu, R. J . P.; Moreau, J . J . E.; Pataud-Sat,
M. Organometallics 1985, 4, 623.
(4) Scubert, U.; Mu¨ller, C. J . Organomet. Chem. 1991, 418, C6.
(5) Osakada, K.; Hataya, K.; Tanaka, M.; Nakamura, Y.; Yamamoto,
T.; Yamamoto, A. J . Chem. Soc., Chem. Commun. 1993, 576.
(6) Shimada, S.; Tanaka, M.; Honda, K. J . Am. Chem. Soc. 1995,
117, 8289. Shimada, S.; Tanaka, M.; Shiro, M. Angew. Chem., Int. Ed.
Engl. 1996, 35, 1856.
with Pt complexes having diorganosilyl ligands would
lead to the formation of 1,2-bis(silyl)alkane or 2,5-di-
sila-1-metallacyclopentane as its double oxidative ad-
dition product. Actually, Pt(SiHPh2)2(PMe2Ph)2 was
(7) Loza, M.; Faller, J . W.; Crabtree, R. H. Inorg. Chem. 1995, 34,
2937.
(8) Nagashima, H.; Tatebe, K.; Ishibashi, T.; Sakakibara, J .; Itoh,
K. Organometallics 1989, 8, 2495; Nagashima, H.; Tatebe, K.; Itoh,
K. J . Chem. Soc., Perkin Trans. 1 1989, 1707. Nagashima, H.; Tatebe,
K.; Ishibashi, T.; Nakaoka, A.; Sakakibara, J .; Itoh, K. Organometallics
1995, 14, 2868.
(9) Kang, Y.; Kang, S. O.; Ko, J . Organometallics 2000, 19, 1216.
(10) Related late transition metal complexes, see: Lemanski, M. F.;
Schram, E. P. Inorg. Chem. 1976, 15, 1489. Curtis, M. D.; Greene, J .
J . Am. Chem. Soc. 1978, 100, 6362. Curtis, M. D.; Greene, J .; Butler,
W. M. J . Organomet. Chem. 1979, 164, 371. Curtis, M. D.; Epstein, S.
P. Adv. Organomet. Chem. 1981, 19, 213. Gilges, H.; Schibert, U.
Organometallics 1998, 17, 4760. Wada, H.; Tobita, H.; Ogino, H.
Organometallics 1997, 16, 3870. Tobita, H.; Hasegawa, K.; Minglana,
J . J . G.; Luh, L.-S.; Okazaki, M.; Ogino, H. Organometallics 1999, 18,
2058. Delpach, F.; Sabo-Etienne, S.; Daran, J .-C.; Chaudret, B.;
Hussein, K.; Marsden, C. J .; Berthelat, J .-C. J . Am. Chem. Soc. 1999,
121, 6668.
(11) Ozawa, F.; Sugawara, M.; Hayashi, T. Organometallics 1994,
13, 3237. Ozawa, F. J . Organomet. Chem. 2000, 611, 332. See also:
Ozawa, F.; Kamite, J . Organometallics 1998, 17, 5630.
(12) Murakami, M.; Yoshida, T.; Ito, Y. Organometallics 1994, 13,
2900.
(13) Watanabe, H.; Saito, M.; Sutou, N.; Nagai, Y. J . Chem. Soc.,
Chem. Commun. 1981, 617. Watanabe, H.; Saito, M.; Sutou, N.;
Kishimoto, K.; Inose, J .; Nagai, Y. J . Organomet. Chem. 1982, 225,
343.
reported to react with acetylene to afford Pt(SiPh2-
CHdCH-SiPh2)(PMe2Ph)2.16 In this paper we report
that the reaction of an arylallene with a platinum
complex with diphenylsilyl ligands gives not only a new
disilaplatinacyclopentane but also four- or five-mem-
bered silaplatinacycles depending on the conditions.
(4-Fluorophenyl)allene reacts with an equimolar
17
amount of Pt(SiHPh2)2(PMe3)2 at room temperature
to produce Pt(SiPh2C(dCHC6H4F-4)CH2)(PMe3)2 (1),
(14) Murakami, M.; Andersson, P. G.; Suginome, M.; Ito, Y. J . Am.
Chem. Soc. 1991, 113, 3987. Murakami, M.; Suginome, M.; Fujimoto,
K.; Nakamura, H.; Andersson, P. G.; Ito, Y. J . Am. Chem. Soc. 1993,
115, 6487.
(15) Hayashi, T.; Kobayashi, T.; Kawamoto, A. M.; Yamashita, H.;
Tanaka, M. Organometallics 1990, 9, 280. Hayashi, T.; Kawamoto, A.
M.; Kobayashi, T.; Tanaka, M. J . Chem. Soc., Chem. Commun. 1990,
563.
(16) Eaborn, C.; Metham, T. N.; Pidcock, A. J . Organomet. Chem.
1977, 131, 377.
10.1021/om010266u CCC: $20.00 © 2001 American Chemical Society
Publication on Web 09/28/2001

4452 Organometallics, Vol. 20, No. 22, 2001
Communications
Ta ble 1. Cr ysta llogr a p h ic Da ta of Com p lexes 1-3
1
2
3
chemical formula
fw
C27H35FP2PtSi C39H45FP2PtSi C36H42F2P2PtSi
663.70
845.97
797.85
cryst syst
space group
a, Å
b, Å
c, Å
monoclinic
monoclinic
monoclinic
P21/n (No. 14) P21/c (No. 14) P21/n (No. 14)
16.803(3)
8.349(2)
20.434(8)
103.17(2)
2791(1)
4
5.184
1312
1.579
11.517(2)
27.949(3)
12.952(2)
111.52(1)
3878(1)
4
3.778
1696
1.449
9.792(2)
18.710(3)
19.296(2)
94.95(2)
3499.1(8)
4
4.153
1592
1.514
â, deg
V, Å3
Z
µ, mm-1
F(000)
D
calcd, g cm-3
cryst size, mm × 0.64 × 0.32
0.58 × 0.32
0.52 × 0.34
× 0.32
5.0-55.0
8281
mm × mm
2θ range, deg
no. of unique
reflns
× 0.26
5.0-55.0
6801
× 0.29
5.0-55.0
9084
no. of used reflns 3444
4447
5024
(I>3.0σ(I))
no. of variables
289
406
379
F igu r e 2. ORTEP drawing of 2 at the 50% ellipsoidal
level. Selected bond distances (Å) and angles (deg): Pt-
P1 2.349(2), Pt-P2 2.344(2), Pt-Si1 2.365(2), Pt-Si2
2.374(2), Si1-C1 1.888(6), Si2-C2 1.892(7), C1-C2 1.498-
(8), C2-C3 1.346(8), C3-C4 1.479(9); P1-Pt-P2 96.06-
(7), P1-Pt-Si1 170.98(7), P1-Pt-Si2 93.95(7), P2-Pt-
Si1 90.38(7), P2-Pt-Si2 169.96(7), Si1-Pt-Si2 79.74(7),
Pt-Si1-C1 111.0(2), Pt-Si2-C2 110.2(2), Si1-C1-C2
105.6(4), Si2-C2-C1 106.1(5), Si2-C2-C3 134.1(6),
C1-C2-C3 118.5(7), C2-C3-C4 130.6(7).
R
Rw
0.052
0.035
0.037
0.024
0.035
0.024
NMR signals of the CH2 carbon of 1 and 2 are observed
at δ 20.8 and 38.0, respectively, flanked by 195Pt satellite
1
2
peaks (1, J CPt ) 400 Hz; 2, J CPt ) 88 Hz), while the
signals of the sp2 carbons of the metallacycles appear
at δ 157.8 and 150.0. The NMR analyses of reaction 1
revealed generation of H2SiPh2 in the solution. The
reaction of H2SiPh2 with 1 was conducted in order to
clarify the route of formation of 2. Heating a benzene
solution of a mixture of 1 and H2SiPh2 in 1:3 molar ratio
at 50 °C caused formation of 2 in 34% (eq 3).
while the reaction at 50 °C affords Pt(SiPh2C-
(dCHC6H4F-4)CH2SiPh2)(PMe3)2 (2), as shown in eqs
1 and 2. Molecular structures of the four- and five-
membered silaplatinacycles 1 and 2 were determined
by X-ray crystallography (Figures 1 and 2). The crystal-
lographic data are summarized in Table 1. Complex 1
contains a planar metallacycle ring with highly distorted
bond angles, Si1-Pt-C1 68.1(3)°, Pt-Si1-C2 85.3(4)°,
Pt-C1-C2 103.2(7)°, Si1-C2-C1 95.8(8)°. Despite the
strained ring structure, 1 is stable at room temperature
in the solid state and in solution. The square-planar Pt
center of 2 is included in the five-membered disilamet-
allacyclic ring and is bonded to two PMe3 ligands. The
C2-C3 bond distance (1.346(8) Å) is typical of the
CdC double bond, while the Si-C2-C3 bond angle
(134.1(6)°) is enlarged due to steric repulsion between
the 4-fluorophenylmethylidene substituent and a phenyl
substituent on the Si2 atom. The NMR spectra are also
consistent with the proposed structures. The 13C{1H}
The reaction of (4-fluorophenyl)allene with Pt(SiHPh2)2-
(PMe3)2 in a 3:1 molar ratio affords Pt{C(dCHC6H4F-4)-
CH2SiPh2C(dCH2)CH(C6H4F-4)}(PMe3)2 (3) in 73% yield
(eq 4). The organic product, FC6H4CHdC(Me)SiPh2H,
was obtained from the reaction mixture (34% isolated
yield based on Pt) and characterized by NMR spectros-
copy. Figure 3 shows the molecular structure of 3, which
contains the puckered 4-sila-1-platinacyclohexane ring

Communications
Organometallics, Vol. 20, No. 22, 2001 4453
Sch em e 1
reaction of 1 with (4-fluorophenyl)allene would give a
platinacycle with different stereochemistry at the CdC
double bond than what is observed in compound 3.18 The
reaction of (4-fluorophenyl)allene with 2 at room tem-
perature caused formation of 3 but at a very slow
reaction rate; the conversion is not completed after
stirring a 10:1 mixture of the allene and 2 after 140 h.
This suggests that complex 2 is not a major contributor
for the formation of compound 3 in the reaction in eq 4.
Scheme 1 summarizes the reactions for formation of
several silaplatinacycles. The formation of 2 in reaction
2 probably involves initial formation of 1 and subse-
quent reaction of 1 and H2SiPh2 at 50 °C. Reaction 4,
which produces compound 3, does not involve com-
pounds 1 or 2 as intermediates. The reaction of (4-
fluorophenyl)allene with 2 is much slower than the
reaction shown in eq 2. At present, the mechanism of
formation of 3 is not clear.
In summary, this study proposed a unique reaction
mechanism for formation of 2,5-disilaplatinacyclopen-
tane via initial formation of silaplatinacyclobutane and
its reaction with diorganosilane. The insertion of a
CdC double bond of the arylallene into the Pt-Si bond
of Pt(SiHPh2)2(PMe3)2 takes place smoothly and selec-
tively to cause the formation of unique platinacycles.
F igu r e 3. ORTEP drawing of 3 at the 50% ellipsoidal
level. Selected bond distances (Å) and angles (deg):
Pt-P1 2.286(2), Pt-P2 2.308(2), Pt-C1 2.148(5), Pt-C11
2.061(5), C1-C2 1.512(7), C1-C4 1.500(7), C2-C3 1.335-
(7), Si-C2 1.879(5), Si-C10 1.863(5), C10-C11 1.540(7),
C11-C12 1.343(7); P1-Pt-P2 98.49(6), P1-Pt-C1 170.0-
(1), P1-Pt-C11 88.1(1), P2-Pt-C1 88.9(1), P2-Pt-C11
168.7(1), C1-Pt-C11 85.7(2), Pt-C1-C2 103.8(3),
Pt-C1-C4 114.6(4), C1-C2-C3 121.3(5), C2-C1-C4
115.7(5), Si-C2-C1 119.9(4), C2-Si-C10 110.9(2),
Si-C2-C3 118.3(4), Si-C10-C11 111.9(4), C10-C11-C12
119.4(5), Pt-C11-C10 122.1(4), Pt-C11-C12 118.1(4).
Ack n ow led gm en t. This work was supported by a
Grant-in-Aid for Scientific Research from the Ministry
of Education, Culture, Sports, Science, and Technology,
J apan.
Su p p or tin g In for m a tion Ava ila ble: Experimental pro-
cedures and crystallographic data of 1-3. This material is
available free of charge via the Internet at http://pubs.acs.org.
with 4-fluorophenyl and 4-fluorophenylmethylidene sub-
stituents at each of the two R-carbons. The two 4-fluo-
rophenyl groups and the Pt(PMe3)2 moiety are at the
opposite side of the plane formed by a Si and four carbon
OM010266U
(17) The complex exists as an equilibrium mixture of the cis and
trans isomers in solution. See: Kim, Y.-J .; Park, J .-I.; Lee, S.-C.;
Osakada, K.; Tanabe, M.; Choi, J .-C.; Koizumi, T.; Yamamoto, T.
Organometallics 1999, 18, 1349.
(18) The reaction of (4-fluorophenyl)allene with 1 at 50 °C does not
give 3 but produces an uncharacterized Pt complex.
1
atoms in the metallacycle. The H NMR signals of two
dCH2 hydrogens appear at δ 5.57 and 5.73, while the
signals of Pt-CH- and Si-CH2- hydrogens are ob-
served at δ 4.27 and δ 3.36 and 2.31, respectively. The