Rare-earth-metal/platinum heterobinuclear complexes containing reactive Ln-alkyl groups (Ln = Y, Lu): Synthesis, structural characterization, and reactivity

Article abstract of DOI:10.1021/om900702y

A series of Ln/Pt heterobinuclear complexes, (C₅Me ₄XCH₂PPh₂)Ln(CH₂SiMe ₃)₂(OC₄H₈)PtMe₂ (3a: Ln = Y, X = SiMe₂; 3b: Ln = Lu, X = SiMe<

Full text of DOI:10.1021/om900702y

Organometallics 2009, 28, 6861–6870 6861
DOI: 10.1021/om900702y
Rare-Earth-Metal/Platinum Heterobinuclear Complexes Containing
Reactive Ln-alkyl groups (Ln = Y, Lu): Synthesis, Structural
Characterization, and Reactivity
Yumiko Nakajima and Zhaomin Hou*
Organometallic Chemistry Laboratory, RIKEN Advance Science Institute, 2-1 Hirosawa, Wako,
Saitama 351-0198, Japan
Received August 8, 2009
A series of Ln/Pt heterobinuclear complexes, (C5Me4XCH2PPh2)Ln(CH2SiMe3)2(OC4H8)PtMe2
(3a: Ln=Y, X=SiMe2; 3b: Ln=Lu, X=SiMe2; 4a: Ln=Y, X=CH2; 4b: Ln=Lu, X=CH2), were
prepared by the reaction of (C5Me4XCH2PPh2)Ln(CH2SiMe3)2(OC4H8) with PtMe2(COD) (COD =
1,5-cyclooctadiene). Single-crystal X-ray diffraction studies revealed that these complexes possess a
binuclear framework, in which the two metal centers are bridged by a μ-CH2SiMe3 ligand in addition
to the coordination of the phoshpine side arm of the cyclopentadienyl ligand to the Pt atom. Variable-
temperature NMR spectroscopic studies revealed the fluxional behavior of the μ-CH2SiMe3 ligand in
solution. These complexes underwent intramolecular C-H bond cleavage at the SiMe3 group of the
μ-CH2SiMe3 ligand at elevated temperatures. In the thermolysis of 3b, a silyl-bridged bidentate alkyl
Lu/Pt complex, (C5Me4SiMe2CH2PPh2)Lu(μ-CH2SiMe2CH2)(OC4H8)PtMe2 (6), was isolated and
structurally characterized. The reaction of the Y/Pt complex 3a, which bears the silylene-linked Cp-
phosphine ligand, with [Ph3C][B(C6F5)4] or H2 led to fragmentation (C-Si bond cleavage) of the
ligand to give several unidentified products including Me2Si(CH2PPh2)PtMe2 (5). In combination
with [Ph3C][B(C6F5)4]/AliBu3, the Y/Pt complex 4a, which bears the ethylene-linked Cp-phosphine
ligand, showed moderate activity for the polymerization of isoprene to yield polyisoprene with
isotactic-rich 3,4-microstructures.
Introduction
Ln-OC-TM heteronuclear complexes,2 hydrido-bridged
Ln-H-TM-type complexes,3 and Ln/TM mixed complexes
with a direct Ln-TM bond.2a,4 Most of these complexes
were synthesized by using bis(cyclopentadienyl)-ligated
lanthanide precursors,3a,b,d,e,4a and their reaction chemistry
has remained almost unexplored.
Mixed metal complexes containing two different metals,
such as an electron-rich late transition metal (TM) and an
electron-positive rare-earth (group 3 and lanthanide) metal
(Ln), have drawn considerable attention because they are
expected to exhibit unique reactivity that could result from
the cooperative multimetallic synergy effect of two different
metals. So far, a number of Ln/TM heteronuclear complexes
have been reported,1-3 including the isocarbonyl-bridged
During our studies on the mono(cyclopentadienyl)-
ligated rare-earth-metal complexes as catalysts for olefin
(4) (a) Beletskaya, I. P.; Voskoboynikov, A. Z.; Chuklanova, E. B.;
Kirillova, N. I.; Shestakova, A. K.; Parshina, I. N.; Gusev, A. I.;
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Chim. Acta 2003, 345, 130. (h) Butovskii, M. V.; Tok, O. L.; Wagner, F. R.;
Kempe, R. Angew. Chem., Int. Ed. 2008, 47, 6469.
(5) (a) Luo, Y.; Baldamus, J.; Hou, Z. J. Am. Chem. Soc. 2004, 126,
13910. (b) Li, X.; Baldamus, J.; Hou, Z. Angew. Chem. Int. Ed. 2005, 44,
962. (c) Zhang, L.; Luo, Y.; Hou, Z. J. Am. Chem. Soc. 2005, 127, 14562.
(d) Li, X.; Hou, Z. Macromolecules 2005, 38, 6767. (e) Hou, Z.; Luo, Y.; Li,
X. J. Organomet. Chem. 2006, 691, 3114. (f) Li, X.; Nishiura, M.; Mori, K.;
Mashiko, M.; Hou, Z. Chem. Commun. 2007, 40, 4137. (g) Zhang, H.; Luo,
Y.; Hou, Z. Macromolecules 2008, 41, 1064. (h) Li, X.; Hou, Z. Coord.
Chem. Rev. 2008, 252, 1842. (i) Yu, N.; Nishiura, M.; Li, X.; Xi, Z.; Hou, Z.
Chem. Asian J. 2008, 3, 1406. (j) Nishiura, M.; Mashiko, T.; Hou, Z. Chem.
Commun. 2008, 2019. (k) Fang, X.; Li, X.; Hou, Z.; Assoud, J.; Zhao, R.
Organometallics 2009, 28, 517. (l) Li, X.; Nishiura, M.; Hu, L.; Mori, K.;
Hou, Z. J. Am. Chem. Soc. 2009, 131, 13870.
*Corresponding author. Fax: þ81 48 4624665. E-mail: houz@riken.jp.
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r
2009 American Chemical Society
Published on Web 12/03/2009
pubs.acs.org/Organometallics

6862 Organometallics, Vol. 28, No. 24, 2009
Nakajima and Hou
Chart 1. Phosphino Alkyl-Substituted Cyclopentadienyl,
L1 and L2
0.26 for 2a, respectively. In a similar manner, the signals of
the CH2SiMe3 groups appeared at δ -0.75 (CH2) and 0.26
(SiMe3) for 1b and δ -0.81 (CH2) and 0.26 (SiMe3) for 2b,
respectively. Consistently, the 13C NMR spectra of 1a, 1b,
2a, and 2b each showed one set of a CH2 signal and a SiMe3
signal for the two CH2SiMe3 groups. In the 31P NMR spectra
of the yttrium complexes 1a and 2a, one doublet was
observed with a 1JYP coupling constant of 50.0 Hz (1a) and
23.5 Hz (2a).10 These observations strongly indicate that the
phosphine unit is coordinated to the metal center in solution.
Complexes 1a and 1b reacted with PtMe2(COD) (COD=
1,5-cyclooctadiene) at ambient temperature to give the cor-
responding Ln/Pt heterobinuclear complexes (C5Me4SiMe2-
CH2PPh2)Ln(CH2SiMe3)2(OC4H8)PtMe2 (3a: Ln = Y; 3b:
Ln=Lu), through replacement of the COD ligand on the Pt
center with the phosphine unit in 1a,b (Scheme 1). In these
reactions, several unidentified byproducts were also formed.
The isolation of 3a and 3b was successfully accomplished
by a successive crystallization from Et2O/hexane solution at
-35 °C with a yield of 37% and 35%, respectively. One of the
byproducts, a mononuclear platinum complex with a bidentate
phosphine ligand, PtMe2{Me2Si(CH2PPh2)2} (5), was isolated
as a white solid, which is barely soluble in Et2O or in hexane.
Complexes 3a and 3b are stable at room temperature. Any
decomposition of 3a or 3b to yield 5 was not observed even at
high temperatures. Hence, it is plausible that fragmentation
of the C5Me4SiMe2CH2PPh2 ligand occurs concurrently
with the formation of 3a and 3b to afford 5 as a result of
Si-C bond cleavage. The similar Si-C bond cleavage in Cp
ligands was also reported previously.11
The reactions of 2a and 2b with PtMe2(COD) proceeded in
the similar manner to produce the heterobinuclear com-
plexes (C5Me4C2H4PPh2)Ln(CH2SiMe3)2(OC4H8)PtMe2
(4a: Ln = Y; 4b: Ln = Lu) (Scheme 1). In these reactions,
unidentified byproducts were also formed, and complexes 4a
and 4b were isolated in 20% and 21% yields, respectively.
The solid-state structures of 3a, 3b, and 4a were deter-
mined by single-crystal X-ray structural analyses. The OR-
TEP diagrams of 3a and 4a are depicted in Figures 1 and 2,
respectively. Selected bond distances and bond angles of 3a,
3b, and 4a are summarized in Table 1. Complex 3b adopts the
same conformation as that of 3a and 4a, and the ORTEP
diagram is omitted. In both structures of 3a and 3b, the
hydrogen atoms on C5 were located in the difference Fourier
map and refined with isothermal parameters.
polymerization5 and other chemical transformations,6-8 we
became interested in the use of these complexes as building
blocks for the construction of the Ln/TM heteronuclear
complexes. We recently reported the synthesis of the d-f
heterobinuclear Ln/TM hydrido complexes as the first ex-
ample of a Ln/TM heteronuclear complex containing a
mono-Cp* Ln unit (Cp* = C5Me5), such as (C5Me5)Lu-
(OC4H8)(μ-H)2(μ-η1:η1-RPR0R00)Ru(C5Me5) (R=C6H4, R0 =
R00 =Ph; R=CH2, R0 =Me, Ph, R00 =Me, Ph).9 However,
the synthesis of these complexes was achieved at the sacrifice
of the reactive Lu-CH2SiMe3 groups by alkane (SiMe4)
elimination reaction between (C5Me5)Lu(CH2SiMe3)2-
(OC4H8) and (C5Me5)Ru(PR3)H3 (R = Me, Ph).9a To syn-
thesize a Ln/TM complex that could possess the reactive
Ln-alkyl groups, we envisioned that a half-sandwich rare-
earth-metal dialkyl complex having a phosphine unit at the
side arm of the cyclopentadienyl ligand (e.g., [C5Me4-
SiMe2CH2PPh2]- (L1) and [C5Me4C2H4PPh2]- (L2)) would
serve as a useful building block, because the phosphine unit
could form a strong bond with a late transition metal and
thus bring the two metal centers to a reasonable vicinity
without losing a Ln-C bond. Herein, we report a Ln/Pt
heterobinuclear complex containing a mono-Cp0-ligated Ln-
alkyl unit (Cp0 =η5-C5Me4XCH2PPh2, X=SiMe2,CH2) by
use of a phosphine-side-arm-containing half-sandwich rare-
earth-metal dialkyl complex as a starting material. Some
fundamental reactivity of the Ln/Pt heterobinuclear com-
plex, including intramolecular C-H bond cleavage of a
SiMe3 group, is also described.
Results and Discussion
Mono-Cp0 yttrium/lutetium dialkyl complexes supported
by L1 or L2, (C5Me4XCH2PPh2)Ln(CH2SiMe3)2(OC4H8)
(1a: Ln=Y, X=SiMe2; 1b: Ln=Lu, X=SiMe2; 2a: Ln=
Y, X=CH2; 2b: Ln=Lu, X=CH2), were prepared by the
reaction of Ln(CH2SiMe3)3(OC4H8)2 (Ln=Y or Lu) with an
equimolar amount of (C5Me4XCH2PPh2)H (X=SiMe2, X=
CH2) (Scheme 1). Complexes 1a, 1b, 2a, and 2b were
obtained as oily products but could be identified by the 1H,
13C, and 31P NMR spectra. In the 1H NMR spectra of 1a and
2a, the two CH2SiMe3 groups exhibited one CH2 signal and
one SiMe3 signal at δ -0.49 and 0.28 for 1a and δ -0.75 and
In the structures of 3a, 3b, and 4a, the rare-earth-metal
center is bonded to a cyclopentadienyl group, two methylene
carbon atoms (C1 and C5), and one oxygen atom of tetra-
hydrofuran. The platinum is tightly fixed in the dinuclear
framework via a pendant phosphine ligand to construct a
metallacycle composed of P1, Pt1, Ln1, C11, and a ligand
alkyl chain. Around the Pt1 center, P1, C5, C9, and C10 were
arranged in a distorted square-planar fashion. One of the two
trimethylsilylmethyl groups is bonded to the rare-earth-
metal atom in a terminal fashion, while the other bridges
the platinum and the rare-earth-metal atom.
(6) (a) Nishiura, M.; Hou, Z.; Wakatsuki, Y.; Yamaki, T.; Miyamoto,
T. J. Am. Chem. Soc. 2003, 125, 1184. (b) Nishiura, M.; Hou, Z. J. Mol.
Catal. A Chem. 2004, 213, 101. (c) Zhang, W.-X.; Nishiura, M.; Hou, Z.
J. Am. Chem. Soc. 2005, 127, 16788. (d) Liu, Y.;Nishiura, M.; Wang, Y.;Hou,
Z. J. Am. Chem. Soc. 2006, 128, 5592. (e) Zhang, W.-X.; Nishiura, M.; Hou,
Z. Angew. Chem., Int. Ed. 2008, 47, 9700.
(7) (a) Zhang, W.-X.; Nishiura, M.; Mashiko, T.; Hou, Z. Chem.Eur.
J. 2008, 14, 2167. (b) Zhang, W.-X.; Hou, Z. Org. Biomol. Chem. 2008, 6,
1720.
(8) (a) Cui, D.; Nishiura, M.; Hou, Z. Macromolecules 2005, 38, 4089.
(b) Jaroschik, F.; Shima, T.; Li, X.; Mori, K.; Ricard, L.; Le Goff, X.-F.; Nief,
F.; Hou, Z. Organometallics 2007, 26, 5654. (c) Cui, D.; Nishiura, M.; Tardif,
O.; Hou, Z. Organometallics 2008, 27, 2428.
(9) (a) Shima, T.; Hou, Z. Chem. Lett. 2008, 37, 298. (b) Shima, T.;
Hou, Z. Organometallics 2009, 28, 2244.
The bond distances in 3a, 3b, and 4b between Ln1 and Pt1
˚
(ca. 2.8 A) are smaller than the sum of the covalent radii of
(10) The difference in the 1JYP coupling constant between 1a and 2a
might be due to the difference in Y-P bond strength between these two
complexes.
(11) (a) Hultzsch, K. C.; Voth, P.; Beckerle, K.; Spaniol, T. P.;
Okuda, J. Organometallics 2000, 19, 228. (b) Evans, W. J.; Giarikos,
D. G.; Ziller, J. W. J. Organomet. Chem. 2003, 688, 200.

Article
Organometallics, Vol. 28, No. 24, 2009 6863
Scheme 1. Preparation of 3a, 3b, 4a, and 4b
˚
Table 1. Selected Bond Angles (A), Bond Angles (deg), and a
Dihedral Angle (deg) of 3a, 3b, and 4a
3a (Ln1=Y1) 3b (Ln1=Lu1) 4a (Ln1=Y1)
Ln1-Pt1
2.8333(5)
2.417(4)
2.575(4)
2.162(4)
2.102(4)
2.092(4)
131.21(18)
166.8(3)
72.87(12)
2.8214
2.7870(11)
2.409(9)
2.641(4)
2.195(6)
2.077(7)
2.046(9)
128.2(4)
171.9(3)
69.70(13)
5.8
Ln1-C1
2.377(10)
2.542(9)
2.137(11)
2.0646(12)
2.049(10)
132.9(5)
166.9(5)
73.6(3)
Ln1-C5
Pt1-C5
Pt1-C9
Pt1-C10
Ln1-C1-Si1
Ln1-C5-Si2
Ln1-C5-Pt1
C5-P1-C10-C9 6.6
-11.9
Figure 1. Molecular structure of 3a (ellipsoids drawn at the
50% probability level; hydrogen atoms except methylene pro-
tons on C5 are omitted for clarity).
˚
˚
Ln-C5 distances, 2.575(4) A for 3a, 2.542(9) A for 3b, and
2.641(4) A for 4a, are significantly elongated as a result of
˚
μ-bridging coordination between Ln and Pt. These values
correspond with μ-bridging groups, Y-Me-Y motifs with
14
˚
Y-C distances of 2.51-2.61 A and Y-CH2R-M motifs
i
n
(R = SiMe2NSiMe3, Pr, Pr, M = Y, Al) with Y-C dis-
tances of 2.54-2.79 A.15 The Ln-C5-Si2 bond angles, 166-
˚
172°, which are much larger than those of Ln1-C1-Si1 by
ca. 30-45°, are similar to those of a previously reported
μ-CH2SiMe3 group.16 The Pt1-C5 bond lengths are slightly
longer than Pt1-C9 and Pt1-C10 bond lengths, on the basis
of the different coordination fashion: C5 as a neutral L-type
ligand and C9and C10 as a 1e anionic X-type ligand. However,
the difference in these bond distances is quite trivial, and all
these values are almost within the range of values quoted in the
literature for various bidentate phosphine-supported PtMe2
17
˚
complexes, with Pt(II)-C bond lengths of 2.0-2.2 A.
The structure of 5 was also determined by a single-crystal
X-ray analysis (Figure 3). There is a C2 rotation axis on the
Figure 2. Molecular structure of 4a (ellipsoids drawn at the
50% probability level; hydrogen atoms, disordered tetrahydro-
furan carbons, and disordered trimethyl group on SI2 are
omitted for clarity).
(14) (a) Evans, W. J.; Drummond, D. K.; Hanusa, T. P.; Doedens, R.
J. Organometallics 1987, 6, 2279. (b) Schumann, H.; Keitsch, M. R.;
Demtschuk, J.; Molander, G. A. J. Organomet. Chem. 1999, 582, 70. (c)
Schumann, H.; Keitsch, M. R.; M€uhle, S. H. Z. Anorg. Allg. Chem. 2002,
12
˚
˚
˚
Ln1 (Y: 1.62 A, Lu: 1.56 A) and Pt (1.29 A). These short
Ln1-Pt1 bond distances might be indicative of a metal-metal
bonding interaction. However, because the Pt center is Pt(II)
with 16 electrons in this formalism, it seems that no electrons
are available for a metal-metal bonding interaction.
€
628, 1311. (d) Deitrich, H. M.; Grove, H.; Tornroos, K. W.; Anwander, R. J.
Am. Chem. Soc. 2006, 128, 1458.
(15) (a) Voth, P.; Arndt, S.; Spaniol, T. P.; Okuda, J. Organometallics
2003, 22, 65. (b) Evans, W. J.; Champagne, T. M.; Giarikos, D. G.; Ziller,
J. W. Organometallics 2005, 24, 570. (c) Niemeyer, M. Inorg. Chem. 2006,
45, 9085.
(16) (a) Mertis, K.; Edwards, P. G.; Wilkinson, G.; Malik, K. M. A.;
Hursthouse, M. B. J. Chem. Soc., Dalton Trans. 1981, 705. (b) Davies,
J. I.; Howard, C. G.; Skapski, A. C.; Wilkinson, G. Chem. Commun. 1982,
1077. (c) Howard, C. G.; Wilkinson, G.; Thornton-Pett, M.; Hursthouse,
M. B. J. Chem. Soc., Dalton Trans. 1983, 2025. (d) Kulzick, M. A.; Andersen,
R. A.; Muetterties, E. L.; Day, V. W. J. Organomet. Chem. 1987, 336, 221.
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Font-Bardia, M.; Solans, X. Eur. J. Inorg. Chem. 2002, 2477. (b) Thomas,
J. C.; Peters, J. C. J. Am. Chem. Soc. 2003, 125, 8870.
The Ln-C bond distances vary depending on the coordi-
˚
nation mode. The Ln-C1 distances, ca. 2.4 A, are in the
typical range of a Ln-C single bond.13 Meanwhile, the
(12) Emsley, J., Ed. The Elements, 3rd ed.; Oxford University Press:
New York, 1998.
(13) For examples: (a) Evans, W. J.; Dominguez, R.; Levan, K. R.;
Doedens, R. J. Organometallics 1985, 4, 1836. (b) Evans, W. J.; Brady,
J. C.; Ziller, J. W. J. Am. Chem. Soc. 2001, 123, 7711. (c) Arndt, S.; Spaniol,
T. P.; Okuda, J. Angew. Chem., Int. Ed. 2003, 42, 5075.

6864 Organometallics, Vol. 28, No. 24, 2009
Nakajima and Hou
Figure 3. Molecular structure of 5 (ellipsoids drawn at the 50%
probability level; hydrogen atoms are omitted for clarity) Selec-
˚
ted bond lengths (A) and angles (deg): Pt1-C1 2.093(6), Pt1-P1
2.2844(15), Si1-C2-P1 117.3(3), C2-P1-Pt1 116.4(2).
line determined by Si and Pt1. The Pt atom adopts a square-
planar geometry formed by two phosphine ligands and two
methyl groups. All bond distances and angles in 5 are quite
similar to structurally similar Pt complexes reported in
previous reports.17 Complex 5 was also identified by NMR
and elemental analysis.
Complexes 3a, 3b, 4a, and 4b were further characterized by
1H, 13C, and 31P NMR and elemental analyses. Complexes
3a, 3b, 4a, and 4b exhibit fluxional behavior in solution, and
the shape of the NMR spectral signals changed significantly
according to the temperature. In Figure 4, the Cp0Me proton
signals (1.5-2.5 ppm) and SiMe3 and Cp0SiMe2 proton
signals (-0.5 to - 0.6 ppm) of 3a in the temperature range
60 to -10 °C are shown. At 60 °C, four nonequivalent signals
assigned to Cp0Me were observed at δ 1.94, 1.99, 2.02, and
2.30 (() with the integral ratio of 3H, indicating the lack of
symmetry in the structure of 3a. There are two resonances
both for SiMe3 groups at δ -0.01 and 0.33 (b) and for a
Cp0SiMe2 group at δ -0.24 and 0.19 (2). With a decrease of
temperature, significant broadening of the signals was ob-
served, and three Cp0Me signals coalesced at 30 °C. At 5 °C,
the Cp0Me signals split into two sets of four Cp0Me signals,
δ 1.77, 1.91, 2.25, and 2.37 (() and 1.67, 2.17 (ꢀ2), and 2.28 ()),
with a ratio of 68% to 32%, respectively. In accordance with
this observation, two sets of SiMe3 groups were found at δ 0.09
and 0.46 (b) and at δ -0.01 and 0.41(O), and two sets of SiMe2
groups were found at δ -0.56 and 0.36 (2) and δ -0.04 and
0.15 (4).
Figure 4. Variable-temperature 1H NMR spectra (300 MHz) of
3a showing (a) the Cp0Me region and (b) the Cp0SiMe2 and
SiMe3 group region in toluene-d8 (**). The signal marked with
(*) is TMS, the signals marked with $ and # are SiMe2CH2PPh2
and μ-CH2, respectively.
ambient temperature split into two different signal sets at low
temperature. The LnCH2 and PtMe signals were observed as
a multiplet on the basis of a multiple coupling system, and
full assignment of these signals was performed by two-
dimensional (COSY, HSQC, HMBC, NOESY) NMR mea-
surements.18 At elevated temperature, two LnCH2 groups,
one terminal η1-CH2 and one bridging μ-CH2, were observed
as a broad signal in the 1H NMR spectrum. Two methylene
protons of the terminal alkyl group, η1-CH2, were found in a
characteristic high-field region at δ -1.0 to -0.7, whereas
bridging methylene signals, μ-CH2, were slightly shifted to
low field and observed around δ -0.2 to -0.6 and δ 0.1-0.9
in a diastereotopic fashion with the integral intensity of 1H,
respectively. Two different signals were also observed for
PtMe, one broad signal around δ 0.50-0.75 and one doublet
The 1H NMR spectra of 3b, 4a, and 4b also changed in a
similar manner according to the temperature change and
exhibit two sets of signals for trimethylsilylmethylene groups
and Cp0Me4 groups at low temperature, i.e., four SiMe3
signals, four Cp0SiMe2 signals, and eight Cp0Me signals.18
These spectral data are indicative of the presence of an
isomerization process between the two isomers at ambient
temperature. At elevated temperature, the isomerization rate
is faster and signals were observed at an averaged location of
these two isomers.
Consistent with the signal changes of Cp0Me, Cp0SiMe3,
and SiMe3 groups, the signals for metal-coordinating
alkyl groups, LnCH2 and PtMe in 3a, 3b, 4a, and 4b, also
changed according to the temperature; that is, the signals at
around δ 1.0 with a coupling to the phosphorus nucleus (JPH
5-6 Hz), accompanied with a 195Pt satellite signal, JPtH
50-60 Hz.
≈
≈
At low temperatures (-10 to -20 °C), each isomer exhibits
two LnCH2 signals and two PtMe signals. Two sets of
terminal alkyl methylene signals (η1-CH2) were observed in
a diastereotopic fashion at δ -1.4 to -0.4 with a normal
2
1
geminal coupling constant of JHH ≈ 10-11 Hz in the H
NMR spectrum. In the spectrum of 3a and 4a, the η1-CH2
signals were observed as a doublet of doublets as a result of
both a geminal coupling and a coupling to yttrium, 2JYH
≈
3-4 Hz. Four bridging alkyl signals, μ-CH2, were observed
around δ -1.4 to 1.1 as a diastereotopic multiplet based on a
coupling to phosphorus, platinum, and yttrium. In the 13C
NMR spectrum, η1-CH2 was observed in the normal range of
rare-earth-metal-coordinating methylene signals, around δ
32-36. The μ-CH2 signals were observed upfield compared
1
(18) Results of variable-temperature experiments as well as H and
13C NMR spectral data of 3a, 3b, 4a, and 4b are supplied as Supporting
Information, which is available via the Internet at http://pubs.acs.org.

Article
Organometallics, Vol. 28, No. 24, 2009 6865
with a terminal alkyl methylene group, one around δ 15-18
and the other around δ 4-6 as a result of coordination to
platinum. There are two PtMe environments for each iso-
mer, cis and trans to the phosphorus atom. The 13C NMR
spectrum exhibits a coupling of the PtMe carbons to the
31P nucleus, 2JPC-cis = 5-8 Hz or 2JPC-trans = 100-107 Hz,
although the satellite peaks coupled to 195Pt were obscured
for most cases.
Scheme 2. Possible Isomerization Mechanism
The fact that two PtMe groups, η1-CH2 and η2-CH2, were
observed separately through the whole temperature range
60 to -20 °C excluded the site exchange process either bet-
ween η1-CH2 and μ-CH2 or between two PtMe groups.
Therefore, we propose two possible ligand exchange pro-
cesses, which can explain the observed fluxional behavior in
the NMR spectrum: (a) a site exchange of μ-CH2SiMe3
around the Pt-Y bond and (b) a site exchange between
μ-CH2SiMe3 and PtMe (Scheme 2). However, full assign-
ment of the PtMe and CH2 signals is not straightfor-
ward because the signal shapes are obscured due to the
multicoupling system and overlaps of several signals.
Therefore, the isomerization mechanism still remains incon-
clusive.
There is a possibility of ligand-site exchange around an
yttrium, which is accompanied by dissociation of a tetra-
hydrofuran molecule. However, it was found that the iso-
merization proceeded both in tetrahydrofuran-d8 and in
toluene-d8 at room temperature. These results strongly in-
dicate that dissociation of tetrahydrofuran is not essential for
the isomerization.
distorted heterobinuclear μ-methylene complexes.19 In the
13C NMR spectrum, the η1-CH2 unit in the terminal
CH2SiMe3 group was observed as a singlet at δ 33.3. The
μ-CH2 carbon was observed at higher field at δ 6.2 as a
doublet with 2JPC=3.3 Hz. There are two doublets for PtMe
at δ 0.75 (3JPH=5.5 Hz) and at δ 1.04 (3JPH=6.0 Hz) in the
1H NMR spectrum, with satellite signals to 195Pt (2JPtH
≈
55-58 Hz). The corresponding carbon signals were observed
at δ 1.2 and δ 7.9 with a coupling to the phosphorus nucleus.
The structure of 6 was determined by a X-ray analysis by
use of a single crystal obtained from a cold Et2O solution. An
ORTEP depiction of 6 is shown in Figure 5, together with
selected bond lengths and bond angles.
Around Pt1, four atoms, P1, C1, C5, and C6, were set in a
square-planar arrangement. The Lu atom is bonded to a Cp
group, two methylene carbons, and one tetrahydrofuran
molecule in a pseudo-piano-stool configuration. The silyl-
bridged bidentate alkyl CH2SiMe2CH2 unit is coordinated to
two metal centers in a μ-η1:η2 fashion, with a short Lu1-C2
During high-temperature NMR measurements of 3a, 3b,
4a, and 4b, gradual decline in the signal intensity was
observed. Hence, the signal change of 3b was monitored at
˚
bond distance of 2.345(8) A. As a result of a tight coordina-
1
90 °C by means of H NMR spectroscopy to reveal intra-
tion of a μ-η1:η2-CH2SiMe2CH2, the Lu1-Pt1 bond distance
of 2.7668(5) A is significantly shorter than that in 3b. Bond
molecular skeletal rearrangement. After 1.5 h, complex 3b
was completely consumed and a Lu/Pt complex with a silyl-
bridged bidentate alkyl group, (C5Me4SiMe2CH2PPh2)Lu-
(μ-CH2SiMe2CH2)(OC4H8)PtMe2 (6), was formed quantita-
tively with release of SiMe4 (eq 1). In this reaction, a C-H
bond at the SiMe3 group of the μ-CH2SiMe3 unit was cleaved
by σ-bond metathesis with the terminal Ln-CH2SiMe3
group. In the case of 3a, 4a, and 4b, similar reactions were
also observed at elevated temperatures (50-90 °C). How-
ever, isolation of the resultants in a pure state was not
successful because of their thermal instability and decom-
position into unidentified products.
˚
angles around the methylene carbon atoms, Lu1-C1-Si1
85.1(3)° and Lu1-C2-Si1 92.8(3)°, are also greatly dis-
torted. These distorted bond angles around the methylene
carbon atom were also found in the above-mentioned methy-
lene-bridged heterobinuclear systems as well as the alkyl-
bridged Y-Li heteronuclear complex.19,20
In attempts to prepare a cationic Ln/Pt species, the reac-
tions of 3a and 4a with 1 equiv of [Ph3C][B(C6F5)4] were
carried out.5,21 In the case of 3a, a very complicated product
mixture was obtained. The fragmentation (C-Si bond
cleavage) of the C5Me4SiMe2CH2PPh2 ligand might take
place as indicated by the 31P NMR. In the case of 4a, which
has a stronger ethylene linker between the Cp group and the
phosphine group in the ligand, the corresponding cationic
species seemed to be generated together with some unidenti-
fied byproduct. However, a full assignment of the cationic
species was not achieved because of the complexity of the
NMR spectra.
In combination with [Ph3C][B(C6F5)4] and AliBu3 (5 equiv),
complex 4a was active for the polymerization of isoprene
Complex 6 was identified by 1H, 13C, and 31P NMR and
1
elemental analyses. In the H NMR spectrum, the η1-CH2
unit exhibited two diastereotopic doublets at δ -0.45 and
0.24 with a coupling of 1JHH = 12.8 Hz. One diastereotopic
μ-CH2 signal was observed at δ -0.14 as a doublet of
doublets based on coupling to both 31P nucleus and the other
geminal proton, 2JPH=8.7 Hz and 2JHH=14.7 Hz, whereas
the other μ-CH2 signal was observed as a broad signal. The
observed geminal coupling constants exhibit larger values
than those observed in 3 and 4. A similar geminal coupling
constant value, 2JHH=ca. 13 Hz, was also observed in some
(19) (a) Park, J. W.; Mackenzie, P. B.; Schaefer, W. P.; Grubbs, R. H.
J. Am. Chem. Soc. 1986, 108, 6402. (b) Ozawa, F.; Park, J. W.; Mackenzie,
P. B.; Schaefer, W. P.; Henling, L. M.; Grubbs, R. H. J. Am. Chem. Soc.
1989, 111, 1319.
(20) Evans, W. J.; Boyle, T. J.; Ziller, J. W. J. Organomet. Chem. 1993,
462, 141.
(21) (a) Zhang, L.; Suzuki, T.; Luo, Y.; Nishiura, M.; Hou, Z. Angew.
Chem., Int. Ed. 2007, 46, 1909. (b) Nishiura, M.; Mashiko, T.; Hou, Z.
Chem. Commun. 2008, 17, 2019. (c) Zhang, L.; Nishiura, M.; Yuki, M.; Luo,
Y.; Hou, Z. Angew. Chem., Int. Ed. 2008, 47, 2642.

6866 Organometallics, Vol. 28, No. 24, 2009
Nakajima and Hou
heterobinuclear skeleton might be extremely reactive. In
combination with [Ph3C][B(C6F5)4]/AliBu3, the Y/Pt com-
plex 4a, which bears the ethylene-linked Cp-phosphine
ligand, is active for the polymerization of isoprene to yield
polyisoprene with isotactic-rich 3,4-microstructures.
Experimental Section
General Procedures. All procedures were performed under a
dry and oxygen-free nitrogen or argon atmosphere using
Schlenk techniques or a glovebox. Solvents (toluene, hexane,
tetrahydrofuran, Et2O) were purified with the SPS-800 solvent
purification system (MBraun) prior to use. C6H5Cl was purified
with the Ultimate solvent system (GlassCountour). Isoprene
was purchased from Junsei Chemical Co., Ltd. and dried over
CaH2 and distilled. LnCl3 (Ln = Y, Lu) were purchased from
Strem and used without further purification. LiCH2SiMe3 was
bought from Aldrich. PtMe2(COD) was purchased from Al-
drich or AZmax Co., Ltd. and used without further purification.
[Ph3C][B(C6F5)4] was purchased from Tosohchem Corporation.
Toluene-d8, THF-d8, and C6D6 were dried over sodium/benzo-
Figure 5. Molecular structure of 6 (ellipsoids drawn at the 50%
probability level; hydrogen atoms except refined methylene pro-
tons on C1 and C2 are omitted for clarity) Selected bond lengths
˚
(A) and angles (deg): Lu1-Pt 2.7668(5), Lu1-C1 2.541(7),
Lu1-C2 2.345(8), Pt1-C1 2.225(8), Pt1-C5 2.124(8), Pt1-C6
2.109(7), Pt1-P1 2.2786(19), Lu1-C1-Pt1 70.6(2), C1-
Lu1-C2 75.3(3), Lu1-C1-Si1 85.1(3), Lu1-C2-Si1 92.8(3),
C1-Si1-C2 106.8(3).
24
phenone ketyl and distilled. Ln(CH2SiMe3)3(THF)2 and
(C5Me4C2H4PPh2)H25 were prepared according to literature
procedures. (C5Me4SiMe2CH2PPh2)H was prepared following
the same procedure for the synthesis of (C5H5SiMe2CH2-
PPh2)H.26 1H and 13C NMR spectra were recorded using the
residual solvent signal as a standard on a JEOL JNM ECA600,
JNM ECP500, JNM AL400, and JNM AL-300. 31P NMR
spectra were recorded on the basis of an external 85% H3PO4
standard. The weight average molecular weight (Mw), the
number-averaged molecular weight (Mn), and the molecular
weight distribution (Mw/Mn) of the polymers were measured by
means of gel permeation chromatography on a TOSOH HLC-
8220 GPC (column: Super HZM-H ꢀ 3) at RT using THF as an
eluent against polystyrene standards. Elemental analyses were
performed by a Mico Corder JM10. Complexes 1a, 1b, 2a, and
2b were obtained as oils, and no elemental analysis was per-
formed.
(0.95 g (mol Y-Pt)-1 h-1) in C6H5Cl at room temperature.
The weight average molecular weight of the resulting poly-
isoprene is Mw = 4.9 ꢀ 105 with a molecular weight distribu-
tion of Mw/Mn=2.1. The 1H and 13C NMR analyses showed
that the resulting polyisoprene possessed isotactic-rich 3,4-
microstructures (3,4-selectivity: 94%, mm 89%, mmmm
51%).5c,21c Complex 4a alone showed no activity for the
polymerization of isoprene. Under the same conditions,
complex 3a was also active for the polymerization of isoprene
(0.15 g (mol Y-Pt)-1 h-1), but the resulting polymer showed a
bimodal GPC profile, indicative of the presence of more than
one active species. These results are in agreement with the
observations described above in the reactions of 3a and 4a with
[Ph3C][B(C6F5)4]. The limited activity of the present catalyst
systems for the polymerization of isoprene might be due to the
low activity (strong bridge) of the bridged CH2SiMe3 group in
the resulting cationic species.22
Preparation of (C5Me4SiMe2CH2PPh2)Y(CH2SiMe3)2(OC4H8)
(1a). The reaction of Y(CH2SiMe3)3(OC4H8)2 (100 mg, 0.20
mmol) with (C5Me4SiMe2CH2PPh2)H (77 mg, 0.20 mmol) was
performed in toluene (1 mL) at RT for 1 h. The volatiles were
removed in vacuo to afford 1a as an oil. By means of NMR
spectroscopy, quantitative formation of 1a was confirmed.
Hydrogenolysis of 3a and 4a with H2 did not afford a
characterizable hydrido product.23 In the case of 3a, complex
5 was formed together with other unidentified products as a
result of C-Si bond cleavage.
1
Spectral data for 1a: H NMR (395.75 MHz, C6D6, RT): δ
-0.49 (br s, 4H, YCH2), 0.19 (s, 6H, SiMe2), 0.28 (s, 18H,
SiMe3), 1.36 (br s, 4H, R-THF), 1.62 (d, 2JHP =6.73 Hz, CH2),
2.07 (s, 6H, Cp0Me), 2.45 (s, 6H, Cp0Me), 3.64 (br s, 4H, β-THF),
3
7.03 (br m, 6H, mþp-Ph), 7.44 (t, 4H, JHH = 3JHP = 8.3 Hz,
Conclusion
o-Ph). 13C NMR (99.45 MHz, C6D6, RT): δ2.3 (d, 3JCP=4.92 Hz,
SiMe2), 4.8 (s, SiMe3), 12.0 (s, Cp0Me), 15.2 (s, Cp0Me), 17.5 (d,
1JCP =12.35 Hz, CH2), 25.6 (s, β-THF), 38.1 (d, 1JYC =40.7 Hz,
YCH2), 68.7 (s, R-THF), 112.1 (s, Cp0-ring), 123.9 (s, Cp0-ring),
127.1 (s, Cp0-ring), 128.8 (d, m-Ph, 3JCP=7.43 Hz), 129.7 (s, p-Ph),
By use of the half-sandwich rare-earth-metal dialkyl com-
plexes bearing Cp ligands with a phosphine side arm, such as
1a,b and 2a,b, to react with a late transition metal complex,
PtMe2(COD), we have prepared the corresponding Ln/
Pt complexes 3a,b and 4a,b through coordination of the
phosphine unit to the late transition metal center, without
loss of a rare-earth-metal alkyl group. These heterobimetal-
lic alkyl complexes seem rather reactive and undergo intra-
molecular C-H bond activation at high temperatures. The
reaction of the Y/Pt complex 3a, which bears the silylene-
linked Cp-phosphine ligand, with [Ph3C][B(C6F5)4] or H2
has led to fragmentation of the ligand, suggesting that the
resulting cationic species or hydrido species of the Y/Pt
2
1
133.0 (d, JCP = 16.57 Hz, o-Ph), 137.5 (d, JCP = 15.6 Hz,
=
ipso-Ph). 31P NMR (160.10 MHz, C6D6, RT): δ -17.02 (d, 1JYP
50.0 Hz).
Preparation of (C5Me4SiMe2CH2PPh2)Lu(CH2SiMe3)2(OC4H8)
(1b). To the C6D6 solution (0.5 mL) containing Lu(CH2SiMe3)3-
(OC4H8)2 (50 mg, 0.086 mmol) was added (C5Me4SiMe2CH2-
PPh2)H (40 mg, 0.10 mmol) at room temperature. The reaction
mixture was kept at 50 °C for 1 h. The quantitative formationof1b
(24) Lappert, M. F.; Pearce, R. J. J. Chem. Soc., Chem. Commun.
1973, 126.
(22) The terminal CH2SiMe3 group in 4a would be removed upon
reaction with 1 equiv of [Ph3C][B(C6F5)4].
(23) The hydrogenolysis of 1a, 1b, 2a, and 2b resulted in the forma-
tion of unidentified complexes. Identification of resultants is still under-
way.
(25) (a) Jutzi, P.; Dahlhaus, J. Synthesis 1993, 684. (b) Krut'ko, D. P.;
Borzov, M. V.; Veksler, E. N.; Kirsanov, R. S.; Churakov, A. V. Eur. J. Inorg.
Chem. 1999, 1973.
(26) Schore, N. E.; Benner, L. S.; LaBelle, B. E. Inorg. Chem. 1981, 20,
3200.

Article
Organometallics, Vol. 28, No. 24, 2009 6867
was confirmed by means of NMR spectroscopy. After removal of
the volatiles, complex 1b was obtained as an oil.
Spectral data for 1b: H NMR (395.75 MHz, C6D6, RT): δ
Spectral data for 3a: 1H NMR (500.16 MHz, toluene-d8,
50 °C): δ -0.76 (br, 2H, YCH2), -0.28 (br, 1H þ 3H, μ-CH2 þ
SiMe2), 0.00 (s, 9H, SiMe3), 0.19 (br s, 3H, SiMe2), 0.36 (s, 9H,
SiMe3), 0.47 (1H, μ-CH2),27 0.58 (br, 3H, PtMe), 0.99 (d, 3H,
1
-0.75 (br s, 4H, LuCH2), 0.01 (s, 6H, SiMe2), 0.26 (s, 18H,
2
2
SiMe3), 1.36 (br s, 4H, β-THF), 1.61 (d, 2H, JHP = 3.96 Hz,
3JHP = 5.50 Hz, JHPt = 49.97 Hz, PtMe), 1.44 (br s, 4H,
CH2), 2.00 (s, 6H, Cp0Me), 2.18 (s, 6H, Cp0Me), 3.57 (br s, 4H,
β-THF), 1.9-2.2 (br, 9H þ 2H, Cp0Me þ CH2), 2.31 (s, 3H,
Cp0Me), 3.89 (br, 4H, a-THF), 7.1 (m, 6H, mþp-Ph), 7.65 (t, 4H,
3JHH=3JHP=8.48 Hz, o-Ph). COSY (toluene-d8, 50 °C): -0.28
3
R-THF), 7.04 (m, 6H, mþp-Ph), 7.40 (t, 4H, JHH = 3JHP
=
7.32 Hz, o-Ph). 13C NMR (99.45 MHz, C6D6, RT): δ 2.2 (d,
2JCP =5.77 Hz, SiMe2), 4.7 (s, SiMe3), 11.7 (s, Cp0Me), 14.8 (s,
Cp0Me), 17.1 (d, 1JCP=18.00 Hz, CH2), 25.3 (s, β-THF), 43.0 (s,
LuCH2), 68.9 (s, R-THF), 112.1 (d, 3JCP = 3.28 Hz, Cp0-ring),
123.1 (s, Cp0-ring), 126.4 (s, Cp0-ring), 128.3 (d, 3JCP=10.64 Hz,
1
to 0.47. H NMR (600.17 MHz, toluene-d8, -10 °C): δ -1.35
(dt, 1H, 2JYH =3.42 Hz, 2JHH =2JHP =6.8 Hz, μ-CH2), -1.09
(dd, 1H, 2JYH =3.10 Hz, 2JHH =11.0 Hz, η1-CH2), -0.96 (dd,
1H, 2JYH = 3.09 Hz, 2JHH = 10.30 Hz, η1-CH2), -0.57 (s, 3H,
SiMe2), -0.49 (dd, 1H, 2JYH = 3.43 Hz, 2JHH = 10.65 Hz, η1-
2
m-Ph), 128.9 (s, p-Ph), 132.7 (d, JCP = 17.20 Hz, o-Ph),
138.7 (br, ipso-Ph). 31P NMR (160.10 MHz, C6D6, RT): δ
-15.57.
CH2), -0.47 (dd, 1H, JYH = 3.47 Hz, JHH = 10.31 Hz, η1-
CH2), -0.10 (dd, 1H, 2JYH=3.78 Hz, 2JHH=10.65 Hz, μ-CH2),
-0.06 (s, 3H, SiMe2), 0.00 (s, 9H, SiMe3), 0.10 (s, 9H, SiMe3),
0.16 (s, 3H, SiMe2), 0.34 (s, 3H, SiMe2), 0.4 (3H, PtMe),27 0.43
(s, 9H, SiMe3), 0.44 (1H, μ-CH2),27 0.48 (s, 9H, SiMe3), 0.84
(1H, μ-CH2),27 0.86 (d, 3H, 3JHP=4.81 Hz, PtMe), 1.03 (d, 3H,
3JHP=5.46 Hz, PtMe), 1.08 (d, 3H, 3JHP=5.16 Hz, PtMe), 1.28
(m, 4H, β-THF), 1.37 (m, 4H, β-THF), 1.66 (s, 3H, Cp0Me), 1.76
(s, 3H, Cp0Me), 1.88 (m, 1H, CH2), 1.91 (s, 3H, Cp0Me), 2.01 (m,
1H þ 2H, CH2), 2.18 (s, 6H, Cp0Me), 2.26 (s, 3H, Cp0Me), 2.28
(s, 3H, Cp0Me), 2.38 (s, 3H, Cp0Me), 3.51 (m, 2H, R-THF), 3.72
(m, 2H, R-THF), 3.87 (m, 2H, R-THF), 4.06 (m, 2H, R-THF),
7.04 (br m, 4H, mþp-Ph), 7.13 (br m, 8H, mþp-Ph), 7.32 (t, 2H,
3JHH =3JHP =8.25 Hz, o-Ph), 7.59 (t, 2H, 3JHH =3JHP =8.43
Hz, o-Ph), 7.66 (t, 2H, 3JHH=3JHP=8.25 Hz, o-Ph), 7.86 (t, 2H,
3JHH=3JHP=8.61 Hz, o-Ph). Two isomers were observed in the
ratio of 68% to 32%. COSY (toluene-d8, -10 °C): -1.35 to 0.84,
-1.09 to -0.49, -0.96 to -0.47, -0.10 to 0.44, 1.88-2.01,
7.04-7.32,7.66, 7.13-7.59, 7.86. 31P NMR (160.1 MHz, C6D6,
RT): δ 8.66 (1JPPt =2084.3 Hz), 12.06 (1JPPt =2128.4 Hz). The
integration ratio of the signals at δ 8.66 and 12.06 is 66:34. Anal.
Calcd for C38H66OPPtSi3Y: C 48.65, H 7.09. Found: C 48.69, H
6.92.
2
2
Preparation of (C5Me4C2H4PPh2)Y(CH2SiMe3)2(OC4H8) (2a).
Tris(trimethylsilylmethyl)yttrium complex Y(CH2SiMe3)3(OC4H8)2
(100 mg, 0.20 mmol) was dissolved in THF (0.5 mL). To this
solution was added (C5Me4C2H4PPh2)H (67 mg, 0.20 mmol) at
room temperature. The solution was stirred at room temperature
for 1 h, and all the volatiles were removed in vacuo to give 2a as an
oil. Complete consumption of Y(CH2SiMe3)3(OC4H8)2 and for-
mation of 2a as a major product were confirmed by the NMR data.
1
Spectral data for 2a: H NMR (300.40 MHz, C6D6, RT): δ
-0.75 (br s, 4H, YCH2), 0.26 (s, 18H, SiMe3), 1.38 (br s, 4H,
β-THF), 2.00 (s, 6H, Cp0Me), 2.03 (s, 6H, Cp0Me), 2.43 (m, 2H,
CH2), 2.61 (m, 2H, CH2), 3.60 (br s, 4H, R-THF), 7.06 (m, 6H,
mþp-Ph), 7.51 (t, 4H, 3JHH =3JHP =8.26 Hz, o-Ph). 13C NMR
(75.45 MHz, C6D6, RT): δ 4.8 (s, SiMe3), 11.6 (s, Cp0Me), 11.9
(s, Cp0Me), 22.1 (d, 2JCP = 14.9 Hz, CH2), 25.6 (br s, β-THF),
1
31.6 (br s, CH2), 33.8 (d, JYC = 43.1 Hz, YCH2), 68.9 (br s,
=
R-THF), 117.2 (br, Cp0-ring), 117.6 (br, Cp0-ring), 122.7 (d, 3JCP
3
8.33 Hz, Cp0-ring), 128.7 (d, JCP = 6.62 Hz, m-Ph), 129.2 (s,
2
p-Ph), 133.3 (d, JCP = 15.8 Hz, o-Ph), 137.3(br, ipso-Ph). 31P
NMR (160.10 MHz, C6D6, RT): δ -15.62 (d, 1JYP =23.5 Hz).
Preparation of (C5Me4C2H4PPh2)Lu(CH2SiMe3)2(OC4H8) (2b).
The reaction of Lu(CH2SiMe3)3(OC4H8)2 (200 mg, 0.34 mmol)
with (C5Me4C2H4PPh2)H (115 mg, 0.34 mmol) was performed in
toluene (2 mL) at 50 °C for 8 h. After removing all the volatiles
in vacuo, complex 2b was obtained as an oil. Quantitative forma-
tion was confirmed by means of NMR spectroscopy.
1
Spectral data for 5: H NMR (395.75 MHz, C6D6, RT): δ
-0.56 (s, 6H, SiMe2), 1.09 (dd, 6H, 3JHP=5.94, 7.91 Hz, 2JHPt
=
68.46 Hz, PtMe), 1.47 (d, 4H, JHP = 10.30 Hz, 3JHPt = 22.56
Hz, CH2), 7.11 (m, 12H, mþp-Ph), 7.69 (m, 8H, o-Ph). 13C
NMR (99.45 MHz, C6D6, RT): δ 0.8 (s, SiMe2), 7.1 (dd, PtMe,
2JCP = 92.7 (trans), 8.8 (cis) Hz), 13.9 (m, CH2), obscured in
C6D6 signals (m-Ph), 129.7 (s, p-Ph), 133.8 (m, o-Ph), 136.6 (d,
ipso-Ph, 1JCP =42.86 Hz). 31P NMR (160.10 MHz, C6D6, RT):
δ 8.93 (s, 1JPPt=1811.7 Hz). Anal. Calcd for C30H36Si1P2Pt1 (5):
C 52.86, H 5.32. Found: C 52.47, H 5.22.
3
1
Spectral data for 2b: H NMR (399.65 MHz, C6D6, RT): δ
-0.81 (br s, 4H, LuCH2), 0.26 (s, 18H, SiMe3), 1.21 (br s, 4H,
β-THF), 1.93 (s, 6H, Cp0Me), 2.08 (s, 6H, Cp0Me), 2.29 (m, 2H,
CH2), 2.57 (m, 2H, CH2), 3.45 (br s, 4H, R-THF), 7.09 (m, mþp-
Ph, 6H), 7.38 (t, 4H, 3JHH = 3JHP = 6.99 Hz, o-Ph). 13C NMR
(100.40 MHz, C6D6, RT): δ 4.9 (s, SiMe3), 11.5 (s, Cp0Me), 11.7
(s, Cp0Me), 22.3 (d, 2JCP = 16.8 Hz, CH2), 25.1 (br s, β-THF),
31.2 (br, CH2), 41.8 (s, LuCH2), 70.2 (br s, R-THF), 117.2 (s,
Cp0-ring), 117.8 (s, Cp0-ring), 122.2 (d, 1JCP=10.8 Hz, Cp0-ring),
Preparation of (C5Me4SiMe2CH2PPh2)Lu(CH2SiMe3)2-
(OC4H8)PtMe2 (3b). To the C6D6 solution (0.4 mL) containing
Lu(CH2SiMe3)3(OC4H8)2 (50 mg, 0.086 mmol) was added
(C5Me4SiMe2CH2PPh2)H (40 mg, 0.10 mmol) at room tem-
perature. After the reaction mixture was stirred at 50 °C for 1 h,
a C6D6 (0.1 mL) solution of PtMe2(COD) (29 mg, 0.087 mmol)
was added to the reaction mixture and the reaction mixture was
128.8 (d, 3JCP=7.53 Hz, m-Ph), 129.8 (s, p-Ph), 133.1 (d, 2JCP
=
16.6 Hz, o-Ph), 136.7 (ipso-Ph). 31P NMR (160.10 MHz, C6D6,
RT): δ -10.40 (br).
Preparation of (C5Me4SiMe2CH2PPh2)Y(CH2SiMe3)2(OC4H8)-
PtMe2 (3a). Complex 1a was prepared in situ by the reaction of
Y(CH2SiMe3)3(OC4H8)2 (100 mg, 0.20 mmol) with (C5Me4-
SiMe2CH2PPh2)H (77 mg, 0.20 mmol) in toluene following the
procedure above. To the toluene solution containing 1a was
added a toluene solution of PtMe2(COD) (77 mg, 0.23 mmol).
After the reaction mixture was stirred for 1 h, all the volatiles were
removed in vacuo. The 31P NMR spectrum revealed the forma-
tion of 3a (78.8%) and 5 (12.5%). Some unidentified products
(8.7%), which exhibited singlets at δ 17.2, 10.2, 2.9 etc., were also
formed. Theresulting slurrywas extracted withEt2O/hexane, and
the extracts were cooled at -35 °C to afford a mixture of 3a
(84.3%) and 5 (15.7%) as small crystals (first crop: 48 mg; second
crop: 48 mg). The mixture of 3a and 5 was extracted with
Et2O and recrystallized at -35 °C to afford pure 3a (70 mg,
0.075 mmol, 37.0% isolated yield). After the extraction, 5
(ca. 1 mg, 0.0015 mmol) was isolated as insoluble white crystals.
stirred for 1 h. After removal of all the volatiles in vacuo, the 31
P
NMR was obtained to reveal the formation of 3b (45.2%), 5
(19.2%), and unidentified complexes (35.6%), which exhibit
several singlets at δ 17.4, 14.8, 14.7, 11.9, 10.2, etc. The resulting
mixture was extracted with hexane/Et2O. On cooling the ex-
tracts at -35 °C, a mixture of 3b (77%) and 5 (23%) was
obtained (46 mg). The mixture was again extracted with Et2O,
and successive recrystallization at -35 °C afforded pure 3b
(31 mg, 0.030 mmol, 35.1%). After extracting, complex 5 was
isolated as an insoluble part (ca. 2 mg, 0.0029 mmol).
Spectral data for 3b: 1H NMR (500.16 MHz, toluene-d8,
2
50 °C): δ -1.00 (br, 1H, η1-CH2), -0.87 (br d, 1H, JHH
=
9.15 Hz, η1-CH2), -0.50 (br, 1H, μ-CH2), -0.16 (s, 3H, SiMe2),
(27) The signal was determined by a two-dimensional NMR spec-
trum. For more detailed spectroscopic data, see the Supporting Infor-
mation, http://pubs.acs.org.

6868 Organometallics, Vol. 28, No. 24, 2009
Nakajima and Hou
-0.02 (s, 9H, SiMe3), 0.14 (s, 3H, SiMe2), 0.35 (s, 9H, SiMe3),
0.62 (1H, μ-CH2),27 0.67 (d, 3H, 3JHP =4.75 Hz, 2JHPt =44.47
(1H þ 2H, CH2),27 2.25 (s, 3H, Cp0Me), 2.30 (s, 3H, Cp0Me),
(br, 1H, CH2), 2.77 (m, 1H, CH2), 2.86 (t, 1H, 3JHH = 3JHP
=
2.31 (s, 3H, Cp0Me), 2.45 (m, 1H, CH2), 2.63 (m, 1H, CH2), 2.7
3
2
Hz, PtMe), 1.09 (d, 3H, JHP = 5.05 Hz, JHPt = 49.92 Hz,
PtMe), 1.44 (br s, 4H, β-THF), 1.92 (br, 3H, Cp0Me), 1.96 (s, 3H,
Cp0Me), 2.05 (s, 3H, Cp0Me), 2.34 (s, 3H, Cp0Me), 3.90 (br s, 4H,
R-THF), 7.06 (m, 2H, p-Ph), 7.12 (br m, 4H, m-Ph), 7.56 (br s,
2H, o-Ph), 7.67 (t, 2H, 3JHH =3JHP =8.48 Hz, o-Ph). The CH2
signal was obscured by broad Cp0Me signals. COSY (toluene-d8,
50 °C): -0.10 to -0.87, -0.50 to 0.62. 1H NMR (600.17 MHz,
toluene-d8, -10 °C): δ -1.27 (d, 1H, 2JHH=11.70 Hz, η1-CH2),
13.72 Hz, CH2), 3.50 (m, 2H, R-THF), 3.71 (m, 2H, R-THF),
3.80 (m, 2H, R-THF), 4.04 (m, 2H, R-THF), 6.95-7.2 (br m,
12H, mþp-Ph), 7.43 (br, 2H, o-Ph), 7.56 (t, 2H, 3JHH =3JHP
=
8.92 Hz, o-Ph), 7.66 (t, 2H, 3JHH=3JHP=8.70 Hz, o-Ph), 7.69 (t,
2H, 3JHH=3JHP=9.12 Hz, o-Ph). Two μ-CH2 protons were not
observed. Two isomers were observed in the ratio of 54% to
46%. Carbon signals for three m-Ph and one p-Ph were obscured
by toluene-d8 signals. Carbon signals for ipso-Ph were not
observed. COSY (toluene-d8, -20 °C): -1.02 to -0.55, -0.92
to -0.45, -0.87 to 0.52, 2.2-2.63, 2.45-2.86, 3.50-3.80,
-1.06 (d, 1H, 2JHH =10.62 Hz, η1-CH2), -0.91 (t, 1H, 2JHH
=
2
3JHP = 6.51 Hz, μ-CH2), -0.66 (d, 2H, JHH = 11.34 Hz, η1-
CH2), -0.56 (s, 3H, SiMe2), -0.09 (br m, 1H, μ-CH2), -0.09 (s,
3H, SiMe2), -0.02 (s, 9H, SiMe3), 0.097 (s, 9H, SiMe3), 0.15 (s,
3H, SiMe2), 0.37 (s, 3H, SiMe2), 0.42 (s, 9H, SiMe3), 0.49 (s, 9H,
3.71-4.04. 31P NMR (160.10 MHz, C6D6, RT): δ 10.76 (s, 1JPPt
=
2078.4 MHz), 10.31 (s, 1JPPt=1931.9 Hz). The integral intensity
ratio of δ 10.76 to δ 10.31 is 42% to 58%. Anal. Calcd for
C37H62OPPtSi2Y: C 49.71, H 6.99. Found: C 49.78, H 6.68.
Preparation of (C5Me4C2H4PPh2)Lu(CH2SiMe3)2(OC4H8)-
PtMe2 (4b). Complex 2b was prepared by the reaction of
Lu(CH2SiMe3)3(OC4H8) (160 mg, 0.275 mmol) with (C5Me4-
C2H4PPh2)H (93 mg, 0.278 mmol) in the same manner as written
above. To the toluene solution of 2b was added PtMe2(COD)
(92 mg, 0.276 mmol) dissolved in toluene (1 mL) at room
temperature, and the mixture was stirred for 2 h. After removal
of all the volatiles in vacuo, the 31P NMR spectrum was
measured to reveal the formation of 4b in a yield of 22.5%
accompanied by the formation of unidentified byproducts,
which exhibit many singlet signals, for example, at δ 14.17,
15.56, 15.63, 15.69, 17.5, etc. The resulting mixture was ex-
tracted with hexane and cooled at -35 °C to afford colorless
crystalline 4b (57 mg, 0.0582, 21.1%).
3
SiMe3), 0.58 (br, 1H, μ-CH2), 0.62 (d, 3H, JHP-cis = 4.80 Hz,
3
PtMe), 0.87 (br, 1H, μ-CH2), 0.92 (d, 3H, JHP-cis = 4.80 Hz,
3
PtMe), 1.07 (d, 3H, JHP-trans = 5.46 Hz, PtMe), 1.24 (d, 3H,
3JHP-trans=4.44 Hz, PtMe), 1.27 (brm, 4H, β-THF), 1.38 (br m,
4H, β-THF), 1.66 (s, 3H, Cp0Me), 1.76 (s, 3H, Cp0Me), 1.91 (s,
3H, Cp0Me), 1.9 (m, 1H, CH2), 2.1 (m, 2H, CH2), 2.13 (s, 3H,
Cp0Me), 2.19 (s, 3H, Cp0Me), 2.2 (1H, CH2),27 2.24 (s, 3H,
Cp0Me), 2.36 (s, 3H, Cp0Me), 2.41 (s, 3H, Cp0Me), 3.52 (br s, 2H,
R-THF), 3.74 (br s, 2H, R-THF), 3.89 (br s, 2H, R-THF), 4.14
(br s, 2H, R-THF), 7.05 (br m, 2H þ 2H, p-Ph), 7.28 (t, 4H þ 4H,
3JHH =3JHP =8.07 Hz, o-Ph), 7.61 (t, 4H, 3JHH =3JHP =7.92
Hz, o-Ph), 7.68 (t, 4H, 3JHH =3JHP =8.43 Hz, o-Ph). The o-Ph
and m-Ph signals are obscured in residual toluene-d8 signals.
Two isomers were observed in the ratio of 53% to 47%. COSY
(toluene-d8, -10 °C): δH-δH -1.27, -1.06 to -0.66, -0.91 to
0.87, -0.09 to 0.58, 1.9-2.1, 2.1-2.2. 31P NMR (160.10 MHz,
C6D6, RT): δ 12.30 (1JPPt = 2172.2 Hz), 8.00 (1JPPt = 2002.2
Hz). The integral ratio of δ 12.3 to δ 8.00 is 55:45. Anal. Calcd
for C38H66OPPtSi3Lu: C 44.56, H 6.50. Found: C 44.86, H 6.49.
Preparation of (C5Me4C2H4PPh2)Y(CH2SiMe3)2(OC4H8)-
PtMe2 (4a). Complex 2a was prepared in situ from the reaction
of Y(CH2SiMe3)(OC4H8)2 (153 mg, 0.31 mmol) and (C5Me4-
C2H4PPh2)H (105 mg, 0.314) in tetrahydrofuran (1 mL). To the
reaction mixture was added a tetrahydrofuran solution (0.5 mL)
containing PtMe2(COD) (102 mg, 0.31 mmol), and the mixture
was further stirred for 12 h at room temperature. After all the
volatiles were removed in vacuo, the formation of 4a (25% yield)
was detected by 31P NMR spectroscopy as well as unidentified
byproducts (75% yield), which exhibit many signals around
δ 14-16. The resulting residue was dissolved in toluene/hexane
solution and cooled at -35 °C to produce pale yellow crystalline
4a (55 mg, 0.062 mmol, 19.8%).
1H NMR (399.65 MHz, C6D6, 60 °C): δ -0.96 (br, 1H, η1-
CH2), -0.88 (br, 1H, η1-CH2), -0.23 (br, 1H, μ-CH2), -0.04 (s,
9H, SiMe3), 0.32 (s, 9H, SiMe3), 0.57 (br m, 3H, PtMe), 0.84
3
2
(μ-CH2),27 1.00 (d, 3H, JHP = 5.95 Hz, JHPt = 52.66 Hz,
PtMe), 1.43 (br s, 4H, β-THF), 1.88 (s, 3H, Cp0Me), 1.96 (s, 3H,
Cp0Me), 2.02 (s, 3H, Cp0Me), 2.20 (s, 3H, Cp0Me), 2.5-3.0 (m,
4H, CH2), 3.91 (br s, 4H, R-THF), 7.09 (m, 2H, p-Ph), 7.14 (m,
4H, m-Ph), 7.53 (br, 2H, o-Ph), 7.63 (t, 2H, 3JHH =3JHP =8.70
Hz, o-Ph). COSY (toluene-d8, 50 °C): -0.96 to -0.88, -0.23 to
0.84. 1H NMR (600.17 MHz, toluene-d8, -20 °C): δ -1.17 (d,
1H, 2JHH =10.98 Hz, η1-CH2), -1.03 (d, 1H, 2JHH =11.04 Hz,
η1-CH2), -0.69 (d, 1H, 2JHH=10.98 Hz, η1-CH2), -0.61 (d, 1H,
2JHH=10.32 Hz, η1-CH2), -0.50 (t, 1H, 2JHH=3JHP=6.80 Hz,
μ-CH2), 0.06 (s, 9H, SiMe3), 0.07 (s, 9H, SiMe3), 0.07 (1H, μ-
CH2),27 0.44 (s, 9H, SiMe3), 0.46 (d, 3H, 3JHP=4.80 Hz, PtMe),
3
0.52 (s, 9H, SiMe3), 0.56 (m, 1H, μ-CH2), 0.97 (d, 3H, JHP
=
Spectral data for 4a: 1H NMR (500.16 MHz, toluene-d8,
65 °C): δ -0.79 (br, 2H, η1-CH2), -0.50 (br, 1H, μ-CH2),
-0.02 (s, 9H, SiMe3), 0.15 (1H, μ-CH2),27 0.32 (s, 9H, SiMe3),
5.52 Hz, PtMe), 1.00 (d, 3H, 3JHP = 6.18 Hz, PtMe), 1.05 (1H,
μ-CH2),27 1.23 (br m, 4H, β-THF), 1.34 (br m, 4H, β-THF), 1.15
(d, 3H, 3JHP=4.86 Hz, PtMe), 1.72 (s, 3H, Cp0Me), 1.76 (s, 3H,
Cp0Me), 1.82 (s, 3H, Cp0Me), 1.97 (s, 3H, Cp0Me), 2.14 (m, 1H,
CH2), 2.22 (m, 2H, CH2), 2.22 (s, 6H, Cp0Me), 2.29 (s, 3H,
Cp0Me), 2.33 (s, 3H, Cp0Me), 2.44 (m, 1H, CH2), 2.64 (m, 1H,
3
2
0.50 (br m, 3H, PtMe), 0.91 (d, 3H, JHP = 5.45 Hz, JHPt
=
48.12 Hz, PtMe), 1.47 (br s, β-THF), 1.86 (br s, 3H, Cp0Me), 1.97
(br, 3H, Cp0Me), 2.01 (br, 3H, Cp0Me), 2.18 (s, 3H, Cp0Me), 2.44
(br, 1H, CH2), 2.68 (br m, 2H, CH2), 2.86 (br, 1H, CH2), 3.86 (br
s, 4H, R-THF), 7.0-7.2 (m, 6H, mþp-Ph), 7.56 (br, 2H, o-Ph),
7.61 (br m, 2H, o-Ph). COSY (toluene-d8, 65 °C): -0.50 to 0.15.
1H NMR (600.17 MHz, toluene-d8, -20 °C): δ -1.02 (dd, 1H,
CH2), 2.76 (d, 2H, 3JHP =17.89 Hz, CH2), 2.85 (t, 1H, 2JHH
=
3JHP = 11.70 Hz, CH2), 3.50 (m, 2H, R-THF), 3.71 (m, 2H,
R-THF), 3.87 (br m, 2H, R-THF), 4.12 (br m, 2H, R-THF), 7.03
(m, 2H, p-Ph), 7.0-7.2 (m, 8H, m-Ph), 7.10 (m, 2H, p-Ph), 7.34
(br, 2H, o-Ph), 7.59 (t, 2H, 3JHH=3JHP=8.35 Hz, o-Ph), 7.66 (t,
2JYH=2.61 Hz, 2JHH=10.62 Hz, η1-CH2), -0.92 (dd, 1H, 2JYH
=
2.92 Hz, 2JHH =10.30 Hz, η1-CH2), -0.87 (td, 1H, 2JYH=2.75
Hz, 2JHH=2JPH=7.05 Hz, μ-CH2), -0.55 (dd, 1H, 2JYH=3.44
Hz, 2JHH =10.65 Hz, η1-CH2), -0.45 (dd, 1H, 2JYH =2.40 Hz,
2JHH = 10.31 Hz, η1-CH2), 0.06 (s, 9H, SiMe3), 0.08 (s, 9H,
SiMe3), 0.20 (dd, 3H, 3JHP = 5.50 Hz, 2JYH = 2.58 Hz, PtMe),
0.44 (s, 9H, SiMe3), 0.51 (s, 9H, SiMe3), 0.52 (1H, μ-CH2, the
coupling constant value is obscured by a signal at δ 0.51), 0.90
(d, 3H, 3JHP=5.50 Hz, 2JHPt=54.6 Hz, PtMe), 0.98 (d, 3H, 3JHP
=6.19 Hz, 2JHPt=54.6 Hz, PtMe), 1.02 (d, 3H, 3JHP=5.50 Hz,
2JHPt = 55.7 Hz, PtMe), 1.27 (br m, 4H, β-THF), 1.34 (br m,
4H, β-THF), 1.72 (s, 3H, Cp0Me), 1.76 (br s, 3H, Cp0Me), 1.78
(br s, 3H, Cp0Me), 1.97 (s, 3H, Cp0Me), 2.19 (s, 3H, Cp0Me), 2.2
2H, JHH = 3JHP = 8.25 Hz, o-Ph), 7.69 (m, 2H, o-Ph). Two
3
1
isomers were observed in the ratio of 55% to 45% in the H
NMR spectrum at -20 °C. COSY (toluene-d8, -20 °C): -1.17
to -0.69, -1.03 to -0.61, -0.50 to 0.56. 31P NMR (160.10
MHz, C6D6, RT): δ 8.22 (br, 1JPPt=2037.4 Hz), 11.85 (br, 1JPPt
=2148.9 Hz). The integral intensity ratio of δ 8.22 to δ 11.85 is
56% to 44%. Anal. Calcd for C37H62OPPtSi2Lu(Et2O): C 46.71,
H 6.88. Found: C 46.77, H 6.59. (For the use of elemental
analysis, microcrystals of 4b precipitated from Et2O solution
were used.)
Formation of (C5Me4SiMe2CH2PPh2)Lu(μ-η1:η2-CH2SiCH2)-
(OC4H8)PtMe2 (6). Complex 3b (17 mg, 0.017 mmol) was

Article
Organometallics, Vol. 28, No. 24, 2009 6869
dissolved in C6D6 (0.4 mL) and heated at 90 °C for 1.5 h.
Quantitative formation of 6 and SiMe4 was confirmed by means
of NMR spectroscopy. A single crystal suitable for X-ray
analysis was obtained from a cold Et2O solution of 6 (-35 °C).
Table 2. Polymerization Condition and Results
polyisoprene
structuree
1H NMR (500.16 MHz, C6D6, RT): δ -0.45 (d, 1H, 2JHH
=
12.8 Hz, η1-CH2), -0.14 (dd, 1H, 2JHH =14.66 Hz, JHP =8.70
f
time yield 1,4- 3,4-
(h)
Mn
(%) (%) (%) (ꢀ105) Mn
Mwf/
2
Hz, μ-CH2), -0.10 (s, 3H, SiMe2CH2P), 0.24 (d, 1H, JHH
=
12.80 Hz, η1-CH2), 0.27 (s, 3H, SiMe2CH2P), 0.54 (s, 3H, Si-
Me2), 0.58 (s, 3H, SiMe2), 0.75 (d, 3H, 3JHP =5.50 Hz, 2JHPt
run
cat
1a 3a/[Ph3C][B(C6F5)4]/
AliBu3
10
4.4
33
67 2.7/3.8 3.2/1.1
=
57.30 Hz, PtMe), 1.03 (m, μ-CH2), 1.04 (d, 3H, 3JHP =5.95 Hz,
2JHPt = 54.50 Hz, PtMe), 1.21 (br m, 4H, β-THF), 1.66 (s, 3H,
Cp0Me), 1.71 (m, 1H, SiMe2CH2P), 2.23 (s, 3H, Cp0Me), 2.28 (s,
3H, Cp0Me), 2.45 (m, 1H, SiMe2CH2P), 2.48 (s, 3H, Cp0Me),
3.55 (br s, 2H, R-THF), 3.73 (br s, 2H, R-THF), 6.99 (t, 1H,
2b 4a/[Ph3C][B(C6F5)4]/
AliBu3
10
27.5
6
94 4.9 2.1
3c 4a/[Ph3C][B(C6F5)4]
4d 4a/AliBu3
3
3
0
0
a Complex 3a (10.3 mg, 0.011); [IP]0/[3a]=500; [3a]/[Ph3C][B(C6F5)4]=1;
[AliBu3]/[3a] = 5. b Complex 4a (10.0 mg, 0.011); [IP]0/[4a] = 500; [4a]/
[Ph3C][B(C6F5)4]=1; [AliBu3]/[4a]=5. c Complex 4a (10.0 mg, 0.011); [IP]0/
[4a] =500; [4a]/[Ph3C][B(C6F5)4]=1. d Complex 4a (10.0 mg, 0.011); [IP]0/
[4a]=500;[AliBu3]/[4a]=5.e Determined by 1Hand13CNMRspectroscopy.
f Determined by gel permeation chromatography (GPC) with respect to a
polystyrene standard.
3
p-Ph), 7.07 (m, 3H, pþm-Ph), 7.13 (d, 2H, JHH = 7.80 Hz,
m-Ph), 7.64 (t, 2H, 3JHH = 3JHP = 8.48 Hz, o-Ph), 7.69 (t, 2H,
3JHH = 3JHP = 8.48 Hz, o-Ph). 13C NMR (100.40 MHz, C6D6,
RT): δ 1.2 (d, 2JCP-cis =4.92 Hz, PtMe), 2.5 (d, 3JCP =1.60 Hz,
1
SiMe2CH2P), 4.0 (d, JCP = 6.72 Hz, SiMe2CH2P), 6.2 (d,
3JCP = 3.3 Hz, μ-CH2), 6.8 (s, SiMe), 7.6 (s, SiMe), 7.9 (d,
2JCP =99.89 Hz, PtMe), 11.4 (s, Cp0Me), 12.9 (s, Cp0Me), 14.9
(d, 2JCP=16.60 Hz, CH2), 15.3 (s, Cp0Me), 17.2 (s, Cp0Me), 25.3
(s, β-THF), 33.3 (s, LuCH2), 70.3 (R-THF), 108.6 (s, Cp0-ring),
123.6 (s, Cp0-ring), 124.4 (s, Cp0-ring), 126.2 (s, Cp0-ring), 129.4
(br s, p-Ph), 129.8 (br s, p-Ph), 132.2 (d, 2JCP=10.74 Hz, o-Ph),
134.6 (d, 2JCP=10.84 Hz, o-Ph), 137.2 (d, 2JCP=38.25 Hz, ipso-
Ph). m-Ph carbons were obscured by the solvent (C6D6) signals.
COSY (C6D6, RT): -0.45 to 0.24, -0.14 to 1.03, 1.71-2.45.
HMQC (C6D6, RT): δH-δC -0.45, 0.24-33.3, -0.14, 1.03-
6.2, -0.10-2.5, 0.27-4.0, 0.54-6.8, 0.58-7.61, 0.75-1.2,
1.04-7.91, 1.21-25.3, 1.66-11.4, 1.71, 2.45-14.9, 2.48-17.2,
3.55, 3.73-70.3, 6.99-129.4, 7.07-129.8, 7.64-132.2,
7.69-134.6. 31P NMR (160.10 MHz, C6D6, RT): δ 11.19 (s,
1JPPt=1955.3 Hz). Anal. Calcd for C34H54OPPtSi2Lu: C 43.63,
H 5.82. Found: C 44.07, H 5.92.
Reaction of 3a with [Ph3C][B(C6F5)4]. To the Et2O solution
containing 3a (20 mg, 0.021 mmol) was added [Ph3C][B(C6F5)4]
(19 mg, 0.021 mmol) at -30 °C. The reaction mixture was stirred at
RT for 1 h, and all the volatiles were removed in vacuo. The
resulting slurry was washed with hexane twice to afford a mixture
of unidentified products. The 31P NMR spectrum exhibited two
singlet signals at δ 8.99 and δ 10.60 with integrations of 66% and
34%, respectively. The former is similar to that of 5.
in vacuo at 60 °C to a constant weight of polyisoprene (104.4 mg,
27.5% yield). Cis/trans content was calculated on the basis of the
integral intensity of CH2CHdC(Me)CH2- signals. The regios-
electivity was calculated on the basis of the integral intensity of
CH2CHdC(Me)CH2- signals.5c,21c
The isoprene polymerizations using 3a/[Ph3C][B(C6F5)4],
3a/[Ph3C][B(C6F5)4]/AliBu3, 4a/[Ph3C][B(C6F5)4], and 4a/Ali-
Bu3 systems were performed in a similar manner. Reaction
conditions and results are shown in Table 2.
Hydrogenolysis of 3a. A J-young sample tube was charged
with a C6D6 solution containing 3a (20 mg, 0.021 mmol). After
the NMR tube was evacuated at -196 °C, H2 gas was admitted.
The sample was then warmed to room temperature and the
reaction was monitored by 1H and 31P NMR spectroscopy.
After 3 days, complex 3a was fully consumed to produce
unidentified complexes, which exhibit broad signals around δ
0.3 and 2.0. In the 31P NMR spectrum, only one singlet, which is
assigned for 5, was observed. After removal of the all the
volatiles, the residue was extracted with Et2O and cooled at
-35 °C to afford single crystals of 5.
Hydrogenolysis of 4a. A J-young sample tube was charged
with a C6D6 solution containing 4a (10 mg, 0.011 mmol). After
the NMR tube was evacuated at -196 °C, H2 gas was admitted.
The sample was then warmed to room temperature, and the
Reaction of 4a with [Ph3C][B(C6F5)4]. To a C6H5Cl solution
(0.5 mL) of 4a (8 mg, 0.0089 mmol) was added a C6H5Cl
solution of [Ph3C][B(C6F5)4] (8 mg, 0.0087 mmol) at -30 °C.
After the mixture was stirred at RT for 2 h, hexane was added.
Cooling the reaction mixture at -35 °C afforded a slurry at the
bottom of the reaction vessel. All the supernatant solution was
removed, and the resulting slurry was washed with hexane twice.
1
reaction was monitored by H NMR spectroscopy. After 5 h,
complex 4a was fully consumed to produce unidentified com-
plexes, which exhibit broad signals around δ 0.3 and 2.2.
Single-Crystal X-ray Analysis for 3a, 3b, 4a, 5, and 6. Crystals
for X-ray analysis were obtained as described in the prepara-
tions. The crystals were manipulated in the glovebox and were
scaled in thin-wall glass capillaries. Data collections of 3a, 3b,
4a, and 6 were performed at -110 °C on a Bruker SMART
APEX diffractometer with CCD area detector, using graphite-
1
After drying in vacuo, an oily residue was obtained. H NMR
(395.75 MHz, THF-d8, RT): δ 0.05 (br, 3H, PtMe), 0.25 (t,
3JHP =11.48 Hz, 2JHPt =49.07 Hz, PtMe), 1.54 (br s, β-THF),
1.91 (s, 3H, Cp0Me), 1.93 (s, 3H, Cp0Me), 1.97 (s, 3H, Cp0Me),
2.25 (s, 3H, Cp0Me), 3.32 (br s, R-THF). Signals of the
CH2SiMe3 groups were obscured and not assigned. 13C NMR
(99.45 MHz, THF-d8, RT): δ 2.3 (s, SiMe3), 10.4 (s, Cp0Me),
10.4 (s, Cp0Me), 11.3 (s, Cp0Me), 12.4 (s, Cp0Me). 31P NMR
(160.10 MHz, THF-d8, RT): δ 11.61 (1JPPt =1967.15 Hz).
A Typical Procedure for Isoprene Polymerization Using 4a
(run 2 in Table 2). In a glovebox, to a 100 mL flask that
contained a magnetic stirrer were added successively AliBu3
(55 μL, 1 M, 0.055 mmol), 5 mL of a C6H5Cl solution of 4a (10.0
mg, 0.011 mmol), and isoprene (380.0 mg, 5.6 mmol). A C6H5Cl
(5 mL) solution of [Ph3C][B(C6F5)4] (10.0 mg, 0.011 mmol) was
added under rapid stirring. After 10 h, the flask was moved out
from the glovebox and the reaction was terminated by adding
methanol containing a small amount of hydrochloric acid. The
precipitated polymer was isolated by decantation and washed
with methanol twice. Then, the obtained polymer was dried
˚
monochromated Mo KR radiation (=0.71069 A). The determi-
nation of crystal class and unit cell parameters was carried out
with the SMART program package.28 The raw frame data were
processed using SAINT29 and SADABS30 to yield the reduction
data file. Data collection of 5 was performed on a Rigaku AFC-
8 with a Saturn 70 CCD detector, and data processing was
performed using CrystalClear.31 Absorption correction was
performed using Numabs.32 The structures were solved by using
the SHELXTL program using the Patterson method for 3a, 3b,
(28) SMART Software User Guide, version 4.21; Bruker AXS, Inc.:
Madison, WI, 1997.
(29) SAINT PLUS, version 6.02; Bruker AXS, Inc.: Madison, WI, 1999
(30) Sheldrick, G. M. SADABS; Bruker AXS, Inc.: Madison, WI, 1998.
(31) CrystalClear SM ver. 1.3.6., Rigaku/MSC Inc.: Texas, 2005.
(32) Higashi, T. Numabs: Numerical Absorption Correction; Rigaku
Corporation: Tokyo, Japan, 1999.

6870 Organometallics, Vol. 28, No. 24, 2009
Nakajima and Hou
Table 3. Experimental Data for the Crystal Structure Determinations of the Complexes 3a, 3b, 4a, 5, and 6
3a
3b
4a
5
6
empirical formula
fw
cryst syst
C38H66OPPtSi3Y
938.15
monoclinic
P21/c
17.8199(18)
10.9688(11)
21.897(2)
C38H60LuOPPtSi3
1018.16
orthorhombic
P212121
10.1882(16)
19.297(3)
21.401(3)
C37H62OPPtSi2Y
894.02
monoclinic
P21/n
9.5886(13)
20.717(3)
20.136(3)
C30H36P2PtSi
681.71
orthorhombic
Pbcn
11.3220(14)
17.025(2)
14.8474(19)
C34H54LuOPPtSi2
935.98
monoclinic
C2/c
28.619(13)
15.3701(16)
18.636(2)
space group
˚
a (A)
˚
b (A)
˚
c (A)
R (deg)
β (deg)
γ (deg)
96.0210(2)
90.600(3)
109.8670(10)
3
˚
V (A )
Z
4256.4(7)
4
1.464
163
4.788
1904
0.20 ꢀ 0.10 ꢀ 0.10
1.87-27.56
25 885
4207.5(12)
4
1.607
163
5.804
2008
0.10 ꢀ 0.05 ꢀ 0.02
1.42-27.51
26 614
3999.6(9)
4
1.485
163
5.063
1808
0.10 ꢀ 0.02 ꢀ 0.02
1.41-27.54
24 626
2862.0(6)
4
1.582
298
5.073
1352
0.08 ꢀ 0.07 ꢀ 0.06
2.16-30.03
69 263
7709.6(14)
8
1.613
163
6.297
3664
0.30 ꢀ 0.20 ꢀ 0.10
1.51-27.55
23 582
Dcalc (g cm-3
T (K)
)
μ(Mo KR) (mm-1
F(000)
cryst size (mm)
)
θ range (deg)
no. of reflns collected
no. of reflns obsd [I>2σ(I)]
6830
5287
3430
3452
6576
no. of indep reflns (Rint
data/restraints/params
absorption corr
)
9623 (0.0475)
9623/0/426
empirical
0.850
0.0313, 0.0581
0.0538, 0.0619
1.454 and -0.905
9534 (0.1036)
9534/0/414
empirical
0.641
0.0478, 0.0630
0.0989, 0.0732
1.938 and -1.025
9038 (0.1348)
9038/36/407
empirical
0.690
0.0526, 0.0713
0.1624, 0.0862
1.657 and -1.031
4180 (0.0508)
4180/0/157
multiscan
1.196
0.0565, 0.1227
0.0681, 0.1295
3.585 and -1.844
8698 (0.0381)
8696/0/370
empirical
1.039
0.0356, 0.1180
0.0509, 0.1227
3.390 and -0.695
goodness-of-fit on F2
R1, wR2 [I > 2σ(I)]
R1, wR2 (all data)
-3
˚
largest diff peak and hole (e A
)
and 6 and the direct method for 4a and 5.33 Refinement was
performed on F2 anisotropically for all the non-hydrogen atoms
except disordered carbon atoms by the full-matrix least-squares
methods. In the structure of 4a, three carbons of one SiMe3
group and four carbons of a THF molecule were disordered with
occupancy of 69.5%/30.5% and 63.1%/36.9%, respectively.
The hydrogen atoms on C5 in 3a and 3b and methylene proton
on C1 and C4 were located by difference Fourier synthesis and
their coordinates. Other hydrogen atoms were placed at the
calculated positions and were included in the structure calcula-
tion without further refinement of the parameters. Crystal data
and processing parameters for 3a, 3b, 4a, 5, and 6 are summari-
zed in Table 3.
Acknowledgment. Financial support by a Grant-in-Aid
for Scientific Research from the Ministry of Education,
Culture, Sports, Science and Technology of Japan is grate-
fully acknowledged. We thank Dr. D. Hahizume for
help with the crystallography of 5. We also thank Dr. H.
Koshino for 13C NMR measurements as well as various
two-dimensional NMR measurements (COSY, HSQC,
HMBC, NOESY) at low temperature.
Supporting Information Available: CIF files of all crystal data
and refinement parameters, atomic parameters including hydro-
gen atoms, and bond lengths and angles for 3a, 3b, 4a, 4b, 5, and
6. Full spectral data for 3a, 3b, 4a, and 4b at variable tempera-
ture. This material is available free of charge via the Internet at
http://pubs.acs.org.
(33) Sheldrick, G. M. SHELXTL, version 5.1; Bruker AXS, Inc.:
Madison, WI, 1998.