Rare-earth metal alkyl and hydrido complexes containing a thioether-functionalized bis(phenolato) ligand: Efficient catalysts for olefin hydrosilylation

Article abstract of DOI:10.1021/om800161u

Rare-earth metal alkyl complexes with tridentate [OSO]-type and tetradentate [OSSO]-type bis(phenolato) ligands, [Ln(L)(CH₂SiMe ₃)(THF)_n] (LH₂ = 2,2′-thiobis(6-tert- butyl-4-methylphenol) (tbmpH₂), 1,3-dithiapropanediylbis(6-tert- butyl-4-methylphenol) (mtbmpH₂), 1,4-dithiabutanediylbis(6-tert- butyl-4-methylphenol) (etbmpH₂); Ln = Y (1-3), Sc (4, 5), Lu (7), Ho (9, 10)), were synthesized from the reactions of the tris(alkyl) complexes [Ln(CH₂SiMe₂)₃(THF)₂] with the corresponding bis(phenol) via alkane elimination. The alkyl complexes were characterized by NMR spectroscopy (Y, Sc, Lu) and elemental analysis as well as by X-ray crystal structure analysis (5, 7). The reaction of [Lu(CH ₂SiMe₃)₃(THF)₂] with H ₂etbmp in a 1:2 ratio led to the formation of the bis(phenolato)-bridged dinuclear complex [Lu₂(etbmp) ₃(THF)₂] (8). The reaction of the holmium alkyl complexes 9 and 10 with PhSiH₃ resulted in the formation of the corresponding hydrido complexes [Ho(L)(μ-H)(THF)_n]₂ (L = tbmp, n = 3, 11; L = etbmp, n = 2, 12). The formation of the yttrium analogues could be observed by NMR spectroscopy. Complexes 2,4, and 5 were tested in the hydrosilylation of a wide variety of aliphatic and aromatic 1-alkenes and 1,5-hexadiene with various silanes (PhSiH₃, "BuSiH₃, and Ph₂SiH₂). In the case of terminal aliphatic alkenes an anti-Markovnikov (1,2) addition takes place with 80-99% regioselectivity. The hydrosilylation of styrene afforded the Markovnikov (2,1) addition product PhHC(SiH2Ph)Me with 97% regioselectivity. The hydrosilylation of 1,5-hexadiene by PhSiH₃ catalyzed by 2 resulted in the formation of a linear product, 1,6-bis(phenylsilyl)hexane (ca. 90%), and a cyclic product, (phenylsilylmethyl)cyclopentane (ca. 10%), whereas with ⁿBuSiH ₃ 84% of the cyclic product was obtained.

Full text of DOI:10.1021/om800161u

3774
Organometallics 2008, 27, 3774–3784
Rare-Earth Metal Alkyl and Hydrido Complexes Containing a
Thioether-Functionalized Bis(phenolato) Ligand: Efficient Catalysts
for Olefin Hydrosilylation
Marcin Konkol, Malgorzata Kondracka, Peter Voth, Thomas P. Spaniol, and Jun Okuda*
Institute of Inorganic Chemistry, RWTH Aachen UniVersity, Landoltweg 1, D-52074 Aachen, Germany
ReceiVed February 21, 2008
Rare-earth metal alkyl complexes with tridentate [OSO]-type and tetradentate [OSSO]-type bis(phe-
nolato) ligands, [Ln(L)(CH2SiMe3)(THF)n] (LH2 ) 2,2′-thiobis(6-tert-butyl-4-methylphenol) (tbmpH2),
1,3-dithiapropanediylbis(6-tert-butyl-4-methylphenol) (mtbmpH2), 1,4-dithiabutanediylbis(6-tert-butyl-
4-methylphenol) (etbmpH2); Ln ) Y (1-3), Sc (4, 5), Lu (7), Ho (9, 10)), were synthesized from the
reactions of the tris(alkyl) complexes [Ln(CH2SiMe3)3(THF)2] with the corresponding bis(phenol) via
alkane elimination. The alkyl complexes were characterized by NMR spectroscopy (Y, Sc, Lu) and
elemental analysis as well as by X-ray crystal structure analysis (5, 7). The reaction of
[Lu(CH2SiMe3)3(THF)2] with H2etbmp in a 1:2 ratio led to the formation of the bis(phenolato)-bridged
dinuclear complex [Lu2(etbmp)3(THF)2] (8). The reaction of the holmium alkyl complexes 9 and 10 with
PhSiH3 resulted in the formation of the corresponding hydrido complexes [Ho(L)(µ-H)(THF)n]2 (L )
tbmp, n ) 3, 11; L ) etbmp, n ) 2, 12). The formation of the yttrium analogues could be observed by
NMR spectroscopy. Complexes 2, 4, and 5 were tested in the hydrosilylation of a wide variety of aliphatic
n
and aromatic 1-alkenes and 1,5-hexadiene with various silanes (PhSiH3, BuSiH3, and Ph2SiH2). In the
case of terminal aliphatic alkenes an anti-Markovnikov (1,2) addition takes place with 80-99%
regioselectivity. The hydrosilylation of styrene afforded the Markovnikov (2,1) addition product
PhHC(SiH2Ph)Me with 97% regioselectivity. The hydrosilylation of 1,5-hexadiene by PhSiH3 catalyzed
by 2 resulted in the formation of a linear product, 1,6-bis(phenylsilyl)hexane (ca. 90%), and a cyclic
n
product, (phenylsilylmethyl)cyclopentane (ca. 10%), whereas with BuSiH3 84% of the cyclic product
was obtained.
amido,5 silylamido,6 and silanolate7 complexes as well as
Introduction
divalent lanthanide imine or diketoiminate complexes.8 Recently,
Catalytic hydrosilylation of R-olefins is one of the most
versatile and efficient methods for the synthesis of alkylsilanes
and the production of organosilicon compounds on the industrial
scale.1 Rare-earth metal alkyl, amido, and hydrido complexes2
with metallocene3 or mono(cyclopentadienyl)4 ligands have
proven to be efficient catalyst precursors for the hydrosilylation
of olefins. The mechanism of the hydrosilylation catalytic cycle
most probably involves hydride complexes.3d,m In contrast to
the well-established and numerous cyclopentadienyl complexes
of the rare-earth metals, there are only a few types of complexes
with a non-cyclopentadienyl ancillary ligand environment that
have been reported to be active in olefin hydrosilylation
catalysis. Examples include trivalent yttrium and lanthanide
(3) (a) Sakakura, T.; Lautenschla¨ger, H.-J.; Tanaka, M. J. Chem. Soc.,
Chem. Commun. 1991, 40. (b) Molander, G. A.; Julius, M. J. Org. Chem.
1992, 57, 6347. (c) Onozawa, S.; Sakakura, T.; Tanaka, M. Tetrahedron
Lett. 1994, 35, 8177. (d) Fu, P.-F.; Brard, L.; Li, Y.; Marks, T. J. J. Am.
Chem. Soc. 1995, 117, 7157. (e) Molander, G. A.; Nichols, P. J. J. Am.
Chem. Soc. 1995, 117, 4415. (f) Molander, G. A.; Winterfeld, J. J.
Organomet. Chem. 1996, 524, 275. (g) Molander, G. A.; Retsch, W. H.
J. Am. Chem. Soc. 1997, 119, 8817. (h) Molander, G. A.; Corrette, C. P.
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Chem. 1998, 63, 7009. (j) Schumann, H.; Keitsch, M. R.; Winterfeld, J.;
Mu¨hle, S.; Molander, G. A. J. Organomet. Chem. 1998, 559, 181. (k)
Molander, G. A.; Dowdy, E. D.; Noll, B. C. Organometallics 1998, 17,
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J. Organomet. Chem. 1999, 582, 70. (m) Voskoboynikov, A. Z.; Shestakova,
A. K.; Beletskaya, I. P. Organometallics 2001, 20, 2794. (n) Fu, P.-F. J.
Mol. Catal. A: Chem. 2006, 243, 253.
* To whom correspondence should be addressed. Fax: +49 241 80 92644.
E-mail: jun.okuda@ac.rwth-aachen.de.
(4) (a) Trifonov, A. A.; Spaniol, T. P.; Okuda, J. Organometallics 2001,
20, 4869. (b) Hou, Z.; Zhang, Y.; Tardif, O.; Wakatsuki, J. J. Am. Chem.
Soc. 2001, 123, 9216. (c) Tardif, O.; Nishiura, M.; Hou, Z. Tetrahedron
2003, 59, 10525. (d) Trifonov, A. A.; Spaniol, T. P.; Okuda, J. Dalton
Trans. 2004, 2245. (e) Robert, D.; Trifonov, A. A.; Voth, P.; Okuda, J. J.
Organomet. Chem. 2006, 691, 4393. For reviews, see: (f) Arndt, S.; Okuda,
J. Chem. ReV. 2002, 22, 1953. (g) Okuda, J. Dalton Trans. 2003, 2367.
(5) (a) Horino, Y.; Livinghouse, T. Organometallics 2004, 23, 12. (b)
Rasta¨tter, M.; Zulys, A.; Roesky, P. W. Chem. Commun. 2006, 874. (c)
Rasta¨tter, M.; Zulys, A.; Roesky, P. W. Chem. Eur. J. 2007, 13, 3606.
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(1) (a) Hiyama, T.; Kusumoto, T. In ComprehensiVe Organic Synthesis;
Trost, B. M., Ed.; Pergamon Press: Oxford, U.K., 1991; Vol. 8, Chapter 3,
p 12. (b) Marciniec, B. In ComprehensiVe Handbook on Hydrosilylation;
Pergamon Press: Oxford, U.K., 1992. (c) Ojima, I;. Li, Z.; Zhu, J. In
Chemistry of Organic Silicon Compounds; Rappoport, Z., Apeloig, Y., Eds.;
Wiley: Chichester, U.K., 1998; Vol. 2, p 1687. (d) Marciniec, B. In Applied
Homogeneous Catalysis with Organometallic Compounds; Cornils, B.,
Herrmann, W. A., Eds.; Wiley: Weinheim, Germany, 2002; Vol. 1, p 491.
(2) For recent general reviews on rare-earth metal chemistry and
catalysis, see: (a) Anwander, R. In Applied Homogeneous Catalysis with
Organometallic Compounds, 2nd ed.; Cornils, B.; Herrmann, W. A., Eds.;
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(8) (a) Takaki, K.; Sonoda, K.; Kousaka, T.; Koshoji, G.; Shishido, T.;
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K.; Takehira, K. Tetrahedron 2003, 59, 10381. (c) Ruspic, C.; Spielmann,
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10.1021/om800161u CCC: $40.75
2008 American Chemical Society
Publication on Web 07/09/2008

Rare-Earth Metals for Hydrosilylation
Organometallics, Vol. 27, No. 15, 2008 3775
bearing this or a related ligand.10 The molecule of 5 shows C1
symmetry, and both enantiomers are found in the centrosym-
metric crystal structure. As expected, the two bond lengths with
phenoxy oxygen donors, Sc1-O1 and Sc1-O2, are shorter than
the bond distance for THF oxygen donor O3 (2.003(4) and
1.985(3) Å versus 2.136(3) Å). The Sc1-C1 distance of
2.206(4) Å is shorter than the average bond length of 2.251 Å
in the tris(alkyl) precursor [Sc(CH2SiMe3)3(THF)2]11 and is also
shorter than the median bond length of 2.25 Å (64 bonds, lower
quantile 2.224, upper quantile 2.270, quantile 25%) for 27
crystallographically characterized scandium mono-, di-, and
tris(alkyl) complexes with the (trimethylsilyl)methyl group.
However, due to the constraints imposed by the ligand, the
O1-Sc1-O2 angle of 151.72(11)° is significantly smaller than
180°. This effect was also found in a scandium amido complex
bearing the 1,5-dithiapentanediylbis(6-tert-butyl-4-methylphe-
nolate) ligand, [Sc(ptbmp){N(SiHMe2)2}(THF)] (151.1(2)°).12
The two Sc1-S distances of 2.711(2) and 2.860(3) Å in 5 are
apparently longer than the sum of the covalent radii (rc(Sc) +
rc(S) ) 1.44 + 1.02 ) 2.46 Å) but still much shorter than the
sum of metal radius rm(Sc) and van der Waals radius rv(S)
(rm(Sc) + rv(S) ) 1.628 + 1.80 ) 3.428 Å),13 indicating the
presence of coordinative bonds. The Sc1-S1 and Sc1-S2 bond
lengths in 5 differ from each other by 0.15 Å, and the Sc1-S2
bond trans to the more strongly electron donating CH2SiMe3
group is elongated. The coordination environment of the lutetium
atom in 7 is best described as a distorted pentagonal bipyramid.
The configuration of the ligand is pseudo cis-R with both THF
and both phenoxy oxygen atoms trans to each other (O1-Lu1-
O2 ) 147.41(9)°; O3-Lu1-O4 ) 166.54(8)°). As expected,
the S1-Lu1-S2 angle of 58.13(2)° is smaller than the respec-
tive S1-Sc1-S2 angle in 5 (79.80(9)°). The Lu1-C24 bond
distance of 2.369(3) Å is comparable with the bond length
reported in the literature for [Lu(CH2SiMe3)3(THF)2] (2.36 Å)14
and slightly longer than that for [Lu(etbmp)(CH2SiMe3)(THF)]
(2.335(4) Å)9 and than the median bond length of 2.356 Å for
30 crystallographically characterized lutetium complexes featur-
ing the (trimethylsilyl)methyl ligand (54 bonds, lower quantile
2.336, upper quantile 2.374, quantile 25%).
Scheme 1
we reported that lutetium alkyl and hydrido complexes supported
by an [OSO]- or [OSSO]-type bis(phenolato) ligand framework
are active in 1-hexene hydrosilylation.9 Here we report the
synthesis of the alkyl complexes of other rare-earth metals with
linked bis(phenolato) ligands as well as the catalytic activity of
the scandium and yttrium alkyl complexes in the hydrosilylation
of a wide range of terminal aliphatic and aromatic olefins as
well as of 1,5-hexadiene.
Results and Discussion
Alkyl and Hydrido Complexes. The bis(phenols) with an
[OSO]- or [OSSO]-type framework used in this work are shown
in Scheme 1. Reaction of a bis(phenol) with the tris(alkyl)
precursors [Ln(CH2SiMe3)3(THF)2] leads at room temperature,
via SiMe4 elimination, to formation of the corresponding
mono(alkyl) complexes [Ln(L)(CH2SiMe3)(THF)n] (L ) tbmp,
mtbmp, etbmp; Ln ) Y (1-3), Sc (4, 5), Lu (7), Ho (9, 10))
isolated in moderate to good yields (Scheme 2). The products
often contain one to two THF molecules, depending on the
crystallization/isolation method, but can be stored under argon
at -40 °C for several weeks without decomposition.
The THF ligands in the yttrium complex 2 are labile and
could be easily exchanged for pyridine to give the alkyl complex
[Y(etbmp)(CH2SiMe3)(C5H5N)n] (n ) 1, 2, 6) (Scheme 2). The
structure of the alkyl complexes 1-6 was confirmed by NMR
spectroscopy (with the exception of holmium) and by elemental
analysis.
Due to the greater constraints within the SCH2S bridge of
the mtbmp ligand, the two Lu1-S distances of 3.1671(9) and
3.1096(9) Å in 7 are different from and longer than the
respective distances in [Lu(etbmp)(CH2SiMe3)(THF)] (2.962(1)
and 2.846(1) Å).9 Analogously to the scandium complex 5, the
Lu1-S distances are longer than the sum of the covalent radii
(rc(Lu) + rc(S) ) 1.56 + 1.02 ) 2.58 Å) but still shorter than
the sum of metal radius rm(Lu) and van der Waals radius rv(S)
(rm(Lu) + rv(S) ) 1.738 + 1.80 ) 3.538 Å).
X-ray diffraction analyses of single crystals of [Sc(etbmp)-
(CH2SiMe3)(THF)] (5) and [Lu(mtbmp)(CH2SiMe3)(THF)2] ·
2 THF (7), grown from a THF/pentane solution at -40 °C, were
performed. As shown in Figures 1 and 2, both complexes are
monomeric in the solid state. The scandium and lutetium atoms
are six- and seven-coordinate, respectively. The scandium atom
adopts a distorted-octahedral geometry. The alkyl ligand is
located cis to the THF molecule and trans to one of the sulfur
atoms, and the two oxygen donors of the ligand in 5 are arranged
trans to each other, as indicated by the corresponding angles
C1-Sc1-O3 ) 96.68(14)°, C1-Sc1-S2 ) 168.32(11)°, and
O1-Sc1-O2 ) 151.72(11)°. Analogously to the previously
reported lutetium complex [Lu(etbmp)(CH2SiMe3)(THF)],9 the
1,4-dithiabutanediyl-bridged complex 5 adopts a cis-R config-
uration, consistently observed for group 4 metal complexes
The alkyl complexes 1-7 show fluxional behavior in solution,
as indicated by the presence of only one set of signals observed
(10) (a) Capacchione, C.; Manivannan, R.; Barone, M.; Beckerle, K.;
Centore, R.; Oliva, L.; Proto, A.; Tuzi, A.; Spaniol, T. P.; Okuda, J.
Organometallics 2005, 24, 2971. (b) Beckerle, K.; Manivannan, R.; Spaniol,
T. P.; Okuda, J. Organometallics 2006, 25, 3019. (c) Meppelder, G.-J. M.;
Spaniol, T. P.; Okuda, J. J. Organomet. Chem. 2006, 691, 3206. (d)
Beckerle, K.; Manivannan, R.; Lian, B.; Meppelder, G.-J. M.; Raabe, G.;
Spaniol, T. P.; Ebeling, H.; Pelascini, F.; Mu¨lhaupt, R.; Okuda, J. Angew.
Chem., Int. Ed. 2007, 46, 4790. (e) Lian, B.; Spaniol, T. P.; Okuda, J.
Organometallics 2007, 26, 6653. (f) Lian, B.; Beckerle, K.; Spaniol, T. P.;
Okuda, J. Angew. Chem., Int. Ed. 2007, 46, 8507.
(11) Emslie, D. J. H.; Piers, W. E.; Parvez, M.; MacDonald, R.
Organometallics 2002, 21, 4226.
(12) Ma, H.; Spaniol, T. P.; Okuda, J. Dalton Trans. 2003, 4770.
(13) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
University Press: Ithaca, NY, 1960.
(9) Konkol, M.; Spaniol, T. P.; Kondracka, M.; Okuda, J. Dalton Trans.
2007, 4095.
(14) Schumann, H.; Freckmann, D. M. M.; Dechert, S. Z. Anorg. Allg.
Chem. 2002, 628, 2422.

3776 Organometallics, Vol. 27, No. 15, 2008
Konkol et al.
Scheme 2
1
in the H NMR spectra at room temperature. This fluxional
phenomenon is often observed for rare-earth metal complexes6,12
and other transition-metal complexes.15 The presence of Ln-S
coordinative bonds is indicated by slight to apparent downfield
Figure 1. Molecular structure of [Sc(etbmp)(CH2SiMe3)(THF)] (5)
(50% probability ellipsoids). Hydrogen atoms are omitted for clarity.
Selected bond lengths (Å) and angles (deg): Sc1-C1 ) 2.206(4),
Sc1-O1 ) 2.003(4), Sc1-O2 ) 1.985(3), Sc1-O3 ) 2.136(3),
Sc1-S1 ) 2.711(2), Sc1-S2 ) 2.860(3); O1-Sc1-O2 )
151.72(11), O3-Sc1-S1 ) 159.12(9), C1-Sc1-S1 ) 103.45(13),
C1-Sc1-S2 ) 168.32(11), O1-Sc1-O3 ) 93.61(11), S1-Sc1-S2
) 79.80(9).
Figure 2. Molecular structure of [Lu(mtbmp)(CH2SiMe3)-
(THF)2] · 2THF (7) (50% probability ellipsoids). Hydrogen atoms
and solvent molecules are omitted for clarity. Selected bond lengths
(Å) and angles (deg): Lu1-C24 ) 2.369(3), Lu1-O1 ) 2.103(2),
Lu1-O2 - 2.099(2), Lu1-O3 ) 2.334(2), Lu1-O4 ) 2.334(2),
Lu1-S1 ) 3.1671(1), Lu1-S2 ) 3.110(1); O1-Lu1-O2 )
147.41(9), O3-Lu1-O4 ) 166.54(8), S1-Lu1-S2 ) 58.13(2),
C24-Lu1-S2 ) 149.45(8), C24-Lu1-S1 ) 151.08(8).

Rare-Earth Metals for Hydrosilylation
Organometallics, Vol. 27, No. 15, 2008 3777
Table 1. Selected 1H and 13C NMR Spectroscopic Data for Complexes 1-3, 5, and 7 in THF-d8
LnCH2
LnC
δ (ppm)
(multiplicity)
δ (ppm)
(multiplicity)
complex
Ln
L
2JYH (Hz)
1JYC (Hz)
1
2
3
5
7
Y
Y
Y
Sc
Lu
tbmp
-0.84 (d)
-0.94 (d)
-0.85 (d)
-0.11
3.0
3.0
3.5
24.8 (d)
21.8 (d)
24.5 (d)
34.8
45.1
41.6
44.2
etbmp
mtbmp
etbmp
mtbmp
-0.95
29.2
shifts of the SCH2 protons in 2, 3, and 5-7 compared to those
in the corresponding bis(phenol). The aforementioned fluxional
behavior of the alkyl complexes in solution is thought to be
due to a reversible THF or pyridine dissociation/coordination
process that leads to a molecule with a higher symmetry. In
the case of the 1,4-dithiabutanediyl-bridged (2, 5, 6) and 1,3-
dithiapropanediyl-bridged (3 and 7) complexes the THF dis-
sociation would result in a pseudo five-coordinate metal center
with either C2 (trigonal bipyramidal, trans-(O,O)) or Cs sym-
metry (square pyramidal, cis-(O,O)). This would render both
phenyl moieties in the same ligand chemically equivalent,
The holmium alkyl complexes 9 and 10, generated in situ,
were found to react smoothly at room temperature with PhSiH3
to form the corresponding hydride complexes [Ho(L)(µ-
H)(THF)n]2 (L ) tbmp, n ) 3, 11; L ) etbmp, n ) 2, 12)
(Scheme 2). Due to their relatively high solubility the hydride
complexes were isolated in 33 and 42% yields, respectively.
They are stable at -40 °C for several weeks. Although we have
not succeeded in obtaining diffraction-quality crystals, the
identity of both complexes was confirmed by means of elemental
analysis. By analogy with the lutetium hydride [Lu(tbmp)(µ-
H)(THF)2]2,9 a dimeric structure should be expected.
1
resulting in only one set of signals observed in the H NMR
The NMR investigations on the reaction of the yttrium alkyl
complex 1 with PhSiH3 showed the formation of the corre-
sponding hydride 13, as indicated by the presence of a triplet
resonance at δ 7.07 ppm with 1JYH ) 27.5 Hz. The triplet pattern
of the resonance clearly indicates two equivalent yttrium centers
1
spectra at room temperature. Selected H and 13C NMR data
for the alkyl bis(phenolato) complexes are summarized in
Table 1.
1
At room temperature the H NMR spectra (in THF-d8) of
1
the 1,4-dithiabutanediyl-bridged yttrium (2, 6) and scandium
complexes (5) show symmetrical features and four ethylene
bridge protons in the backbone of the bis(phenolato) ligand
appear as a singlet at δ 2.75 (2) and 2.46 ppm (6) or as a very
broad singlet at 2.67 ppm (5). In the case of the 1,3-
dithiapropanediyl-bridged complexes 3 and 7 this resonance is
shifted even more to low field (δ 4.02 ppm, 3; δ 4.04 ppm, 7).
Variable-temperature 1H NMR studies of 2 show that the
fluxionality of the ethylene bridge is frozen out on the NMR
time scale at -90 °C, where two broad signals at δ 2.31 and
3.23 ppm are displayed (Figure 3). In the case of the scandium
analogue 5, this fluxionality is frozen out on the NMR time
scale at -20 °C, and at -80 °C the four ethylene bridge protons
show a typical AA′BB′ pattern (doublets at δ 2.27 and 3.16
ppm) (Figure 4). The activation barrier at coalescence temper-
ature ∆Gcq was estimated to be 50.5 ( 0.8 (∆ν ) 358.6 Hz, Tc
) 268 K) for 5 and 41.3 ( 0.8 kJ mol-1 (∆ν ) 446.2 Hz, Tc
) 223 K) for 2, compared to ∆Gcq ) 38.7 ( 0.8 kJ mol-1 (∆ν
) 380.7 Hz, Tc ) 208 K) for the lutetium analogue.9
in a dimeric yttrium hydride species.4 The H NMR spectrum
shows a Cs-symmetric molecule with a singlet resonance for
t
both Me and Bu groups and two doublets for the aromatic
protons. In contrast to the case for the lutetium analogue, all
attempts to isolate the yttrium hydride 13 failed.
Bis(phenolato)-Bridged Complex. The reaction of 1,4-
dithiabutanediylbis(6-tert-butyl-4-methylphenol) (etbmpH2) with
[Lu(CH2SiMe3)3(THF)2] in a 2:1 ratio resulted in formation of
the bis(phenolato)-bridged complex [Lu2(etbmp)3(THF)2] (8)
(Scheme 2). This complex had also been found as a decomposi-
tion product of the previously reported lutetium hydrido complex
[Lu(etbmp)(µ-H)(THF)]2.9 Diffraction-quality crystals of 8 were
obtained upon storing a THF/pentane solution of the hydride at
-40 °C over a period of several days. An X-ray diffraction
analysis revealed that the compound 8 crystallized in a cen-
trosymmetric space group as a racemate of homochiral dimers
with C2 symmetry.16a As shown in Figure 5, the lutetium atom
adopts a seven-coordinate geometry that can best be described
as a distorted pentagonal bipyramid, as indicated by the
1
Figure 3. Variable-temperature H NMR spectra of [Y(etbmp)(CH2SiMe3)(THF)n] (2).

3778 Organometallics, Vol. 27, No. 15, 2008
Konkol et al.
1
Figure 4. Variable-temperature H NMR spectra of [Sc(etbmp)(CH2SiMe3)(THF)] (5).
Hydrosilylation of 1-Hexene. The yttrium complex 2 was
tested as a precatalyst in the hydrosilylation of 1-hexene
(Scheme 3), and the results are summarized in Table 2.
Three silanes, PhSiH3, nBuSiH3, and Ph2SiH2, have been used
for the hydrosilylation of 1-hexene. In all cases high conversion
(91-100%) and selectivity (98-99%) toward the 1,2-addition
product (Si added to the terminal position) were achieved. At
60 °C hydrosilylation with PhSiH3 gave 91% of conversion after
n
4 h, whereas with BuSiH3 and Ph2SiH2 nearly quantitative
conversion was observed in 1H NMR spectra after 19 h.
Monitoring the hydrosilylation reaction with PhSiH3 at 60 °C
1
by H NMR spectroscopy showed that, after 80% conversion
within the first 2 h, a deactivation of the catalyst took place
and no more than 91% conversion could be reached after the
total reaction time of 4 h. The hydrosilylation of 1-hexene with
a 10-fold excess of PhSiH3 at room temperature showed a
pseudo-first-order dependence with a rate constant of k ) (2.78
( 0.05) × 10-2 min-1 (Figure 6).
Figure 5. Molecular structure of [Lu2(etbmp)3(THF)2] · 2C5H10 (8)
(ellipsoids with 50% probability). Hydrogen atoms and solvent
molecules are omitted for clarity. Selected bond lengths (Å) and
angles (deg): Lu-O1 ) 2.118(5), Lu-O2 ) 2.122(5), Lu-O3 )
2.139(5), Lu-O4 ) 2.316(5), Lu-S1 ) 2.886(2), Lu-S2 )
2.923(2), Lu-S3 ) 2.844(2); O1-Lu-O2 ) 147.1(2), O4-Lu-S3
) 137.77(14), S1-Lu-S2 ) 73.85(6), S2-Lu-S3 ) 145.75(6),
O3-Lu-O4 ) 77.63(19).
The yttrium complex 2 was found to be more active than the
scandium analogue 5 (Table 2, entries 2 and 4). This observation
is in agreement with the literature data showing a correlation
between the increasing ionic radius of Ln3+ and increasing rate
(turnover frequency) of hydrosilylation.3d,5a Mechanistically, it
is very likely that in the first step a silane reacts with the alkyl
complex with formation of a reactive hydride species that is an
active hydrosilylation catalyst. A monomeric d0 metal hydride
has been thought to be an active metal species in hydrosilylation
reactions for several cyclopentadienyl-based early-transition-
metal systems studied so far.3b,d This route is supported by
formation of the yttrium hydride 13 and PhSiH2CH2SiMe3 in
the NMR reaction of 2 with PhSiH3. Moreover, PhSiH2-
corresponding angles O1-Lu-O2 ) 147.1(2)°, S2-Lu-S3 )
145.75(6)°, S1-Lu-O3 ) 141.46(14)°, and S1-Lu-O42 )
139.39(15)°.
Analogously to 7, three Lu-S bond lengths of 2.886(2),
2.923(2), and 2.844(2) Å indicate the presence of coordinative
bonds. The 1H NMR spectrum of 8 shows at room temperature
the equivalence of three ligand moieties, as indicated by the
presence of only one set of signals. Thus, the ethylene bridge
protons in the backbone appear as a singlet at δ 2.78 ppm. The
structure of 8 is remarkably different from that reported for the
lanthanum complex [La2(xytbmp)3] with a 1,2-xylylene-linked
bis(phenolato) ligand, which reveals two unsymmetrically
coordinated lanthanum centers and can be considered as
consisting of the cationic fragment [Ln(OSSO)]+ coordinated
to the anionic fragment [Ln(OSSO)2]-.16b
1
CH2SiMe3 was also observed in the H NMR spectra taken at
the beginning of all hydrosilylation reactions, as indicated by
the presence of two triplet resonances at δ -0.11 (CH2Si) and
3
4.53 ppm (SiH2) with JHH ) 4.8 Hz. The proposed catalytic
cycle is analogous to that proposed by Tilley and Gountchev
for the hydrosilylation of olefins catalyzed by the bis(silylamido)
yttrium hydride [Y(DADMB)(µ-H)(THF)]2.6 It involves a fast
irreversible insertion of the olefin into the metal-hydrogen bond

Rare-Earth Metals for Hydrosilylation
Organometallics, Vol. 27, No. 15, 2008 3779
Scheme 3
Table 2. Hydrosilylation of 1-Hexene Catalyzed by Scandium and Yttrium Bis(phenolato) Complexesa
amt of regioisomer (%)
1,2f 2,1f
entry
1
cat. (metal)
silane
T (°C)
t (h)
conversn (%)b
2 (Y)
PhSiH3
25
25
25
60
50
50
60
50
25
25
50
4.5
24
48
4
41.5
85.5
93
n.d.
n.d.
98
n.d.
n.d.
2
2
3
2 (Y)
4 (Sc)
PhSiH3
PhSiH3
91c
39
99
n.d.
99
80
99
n.d.
>98.5
>98.5
1
n.d.
1
24
65.5
43
19
24
57
19
66d
60e
99
4
5
6
5 (Sc)
2 (Y)
2 (Y)
PhSiH3
Ph2SiH2
nBuSiH3
20
<1
n.d.
<1.5
<1.5
85
96.5
100
7
2 (Y)
nBuSiH3
a Reaction conditions: 0.0136 mmol (2.3 mol %) of 2, 0.0160 mmol (2.7 mol %) of 4, 5 in C6D6, substrate/precatalyst molar ratio of 40, silane/olefin
ratio of 1.02-1.04. b Calculated by 1H NMR spectroscopy. c Ca. 3% of unidentified side products. d The catalytic reaction was halted after about 66%
consumption of 1-hexene. e The catalytic reaction was halted after about 60% consumption of 1-hexene. f The ratio of 1,2- and 2,1-regioisomers was
calculated by integration of the SiH2 resonances in the 1H NMR spectra.
a double bond are observed and the selectivity is governed by
steric and electronic factors of both catalyst and substrate. Thus,
in the case of aliphatic terminal olefins formation of anti-
Markovnikov (1,2-addition) products with high selectivity
(92-99%) has been observed (Table 3, entries 2-5). Surpris-
ingly, 3,3-dimethylbut-1-ene did not undergo hydrosilylation at
25 °C (entry 1). The reaction of trimethylvinylsilane with PhSiH3
in the presence of 2 led to the corresponding 1,2-addition product
with only 85% selectivity (entry 7). In contrast to the case for
the aliphatic olefins, styrene was hydrosilylated with PhSiH3,
giving the secondary addition product (1-phenethyl)phenylsilane
with 97% selectivity (entry 8). With nBuSiH3 no hydrosilylation
of styrene was observed (entry 9), presumably due to steric
effects of the bulkier nBu group. The secondary regioselectivity
for styrene, also observed for other lanthanide and yttrium
hydrosilylation catalysts,3d,4e,5,6 has been rationalized in terms
of ηn coordination between the Lewis acidic/electrophilic metal
center and the π-electron system of styrene, directing the
insertion reaction toward the R-phenylalkyl intermediate. This
stabilization of a rare-earth metal by an aromatic ring has been
commonly observed in other benzyl and arene complexes.3d,4e,18
The interactions between yttrium and the phenyl ring are also
indicated by the deep yellow color of the hydrosilylation reaction
mixture. Moreover, a lutetium hydride complex with a bis(phe-
nolato) ligand, [Lu(etbmp)(µ-H)(THF)]2, was found to react
regioselectively with styrene to yield the 2-phenylethyl complex
[Lu(etbmp)(CH(Ph)CH3)(THF)].9 This strong preference of
Figure 6. Pseudo-first-order plot for the disappearance of 1-hexene
catalyzed by 2 (25 °C, C6D6).
Scheme 4
(15) Chisholm, M. C.; Gallucci, J.; Phomphrai, K. Inorg. Chem. 2002,
41, 2785.
(16) For a similar structural motif, see: (a) Ma, H.; Spaniol, T. P.; Okuda,
J. Angew. Chem. Int. Ed. 2006, 45, 7818. (b) Ma, H.; Spaniol, T. P.; Okuda,
J. Inorg. Chem. 2008, 47, 3328.
(17) (a) Konkol, M.; Okuda, J. Unpublished results. For examples of
yttrium n-alkyl complexes, see: (b) Voth, P.; Arndt, S.; Spaniol, T. P.;
Okuda, J.; Ackerman, L. J.; Green, M. L. H. Organometallics 2003, 22,
65. For a study on yttrium-olefin interactions, see (c) Casey, C. P.;
Hallenbeck, S. L.; Wright, J. M.; Landis, C. R. J. Am. Chem. Soc. 1997,
119, 9680.
to give an alkyl species, which then reacts with a silane to give
a silylated product and to regenerate the hydride. The insertion
of 1-hexene into the metal-hydrogen bond with formation of
an n-hexyl complex has been observed for [Lu(etbmp)(µ-
H)(THF)]2 in C6D6.17a
Hydrosilylation of Monoolefins. We have investigated a
wide range of aliphatic and aromatic olefins in hydrosilylation
n
reactions with PhSiH3 and BuSiH3 catalyzed by complex 2
(18) (a) Mintz, E. A.; Moloy, K. G.; Marks, T. J.; Day, V. W. J. Am.
Chem. Soc. 1982, 104, 4692. (b) Evans, W. J.; Ulibarri, T. A.; Ziller, J. W.
J. Am. Chem. Soc. 1990, 112, 219. (c) Hultzsch, K. C.; Voth, P.; Beckerle,
K.; Spaniol, T. P.; Okuda, J. Organometallics 2000, 19, 228. (d) Voth, P.;
Spaniol, T. P.; Okuda, J. Organometallics 2003, 22, 3921.
(Scheme 4), and the results of these experiments are collected
in Table 3.
As has been noted for other lanthanide and yttrium hydrosi-
lylation catalysts,3–6 both 1,2- and 2,1-additions of a silane to

3780 Organometallics, Vol. 27, No. 15, 2008
Konkol et al.
Table 3. Hydrosilylation of Alkenes Catalyzed by the Yttrium Bis(phenolato) Complex 2a
entry
alkene
silane
T (°C)
t (h)
%-convb
1,2- (%)d
2,1- (%)d
1
2
tBuCHdCH2
PhSiH3
PhSiH3
25
50
50
50
50
50
50
60
60
50
50
50
50
50
50
60
50
50
24
20
63
21
39
54
37
20
41
21
21
19
35
120
21
20
20
69
0
75.5
93
73
89
92
88
72
85
99
99
75
94.5c
0
tBuCHdCH2
n.d.
>99
n.d.
<1
3
tBuCHdCH2
nBuSiH3
98.5
92
n.d.
99
>99
85
1.5
8
n.d.
<1
<1
15
4
5
tBuCH2CHdCH2
nPrC(Me)dCH2
PhSiH3
PhSiH3
6
7
8
CyCHdCH2
Me3SiCHdCH2
PhCHdCH2
PhSiH3
PhSiH3
PhSiH3
3
97
9
PhCHdCH2
Ph2CdCH2
PhC(Me)dCH2
PhCH2CHdCH2
PhCH2CHdCH2
nBuSiH3
PhSiH3
PhSiH3
PhSiH3
nBuSiH3
10
11
12
13
0
8
99
91
100
93.5
95
6.5
5
a Reaction conditions: 0.0136 mmol (2.3 mol %) of 2 in C6D6, substrate/precatalyst molar ratio of 40, silane/olefin ratio of 1.02-1.04. b Calculated
by 1H NMR spectroscopy. c 5-10% of another byproduct was also formed. d The ratio of 1,2- and 2,1-regioisomers was calculated by integration of the
1
resonances in the H NMR spectra.
Scheme 5
generally proceeds via intramolecular carbon-carbon bond
formation, yielding (silylmethyl)cyclopentane.3c–e,4c,5,8a
Thedimerichydridocomplex[Y(η5:η1-C5Me4CH2SiMe2NtBu)(µ-
H)(THF)]2 with a linked amido-cyclopentadienyl ligand was
found to catalyze the hydrosilylation of 1,5-hexadiene with
PhSiH3 (1:1 ratio) to give a mixture of both linear and cyclic
products as well as oligomers.4d The metallocene samarium alkyl
complex [Sm(η5-C5Me5)2{CH(SiMe3)2}] was reported to yield
predominantly (phenylsilylmethyl)cyclopentane, whereas in the
case of [Sm{(η5-C5Me4)2SiMe2}{CH(SiMe3)2}] and (R)-[Sm{(η5-
C5Me4)}{(-)-menthylC5H3}SiMe2{CH(SiMe3)2}] ca. 30% of
linear products arising from a process involving skeletal
rearrangement of 1,5-hexadiene was observed.3d On the other
hand, hydrosilylation of 1,6-heptadiene with PhSiH3 cata-
lyzed by the permethylyttrocene complex [Y(η5-C5Me5)2-
{CH(SiMe3)2}] resulted in the formation of 1,7-
bis(phenylsilyl)heptane.3b Hydrosilylation of 1,5-hexadiene with
PhSiH3 ([Y]:[silane]:[diene] ) 1:82:40) at 50 °C catalyzed by
2 led predominantly to 1,6-bis(phenylsilyl)hexane in ca. 90%
yield with ca. 10% of (phenylsilylmethyl)cyclopentane, as shown
by 1H and 13C NMR spectroscopy. Surprisingly, the analogous
styrene for a secondary insertion into a metal-hydride bond
has been previously reported.19 Both the extension of an alkyl
chain in the case of allylbenzene (entries 12 and 13) and the
lack of an aromatic ring in vinylcyclohexane (entry 6) result in
formation of 1,2-addition products with the silicon added to the
less hindered side. In the case of R-methylstyrene steric effects
presumably prevent interactions between yttrium and the
aromatic ring and the addition of PhSiH3 to the double bond,
as indicated by low conversion (8%) and high selectivity toward
1,2-addition product (99%) (Table 3, entry 11). Furthermore,
no reaction with 1,1-diphenylethylene and trans-1,2-diphe-
nylethene was observed (entry 10). The lack of reactivity toward
trans-1,2-diphenylethene has also been reported for the bis(si-
lylamido) yttrium hydride [Y(DADMB)(µ-H)(THF)]2.6
Hydrosilylation of 1,5-Hexadiene. The possible products of
hydrosilylation of 1,5-hexadiene are summarized in Scheme 5.
Group 8 metal catalysts are generally known to yield predomi-
nantly linear products such as 5-hexenylsilane, 1,5-hexadienyl-
silane, and 1,6-bis(silyl)hexane or silacycloheptane, depending
on the diene/silane ratio and the types of silanes and catalysts.20
In contrast, hydrosilylation catalyzed by rare-earth metals
n
hydrosilylation with BuSiH3 resulted in reversed selectivity,
yielding 84% of the cyclic product (Scheme 6). The proposed
mechanism for hydrosilylation of 1,5-hexadiene catalyzed by
2 is presented in Scheme 7.
Analogously to the hydrosilylation of monoolefins, it is likely
that the reaction of 2 with RSiH3 initiates the catalytic cycle
with concomitant generation of the yttrium hydride. The anti-
Markovnikov addition of the hydride to 1,5-hexadiene leads to
the intermediate yttrium 5-hexenyl complex, which further reacts
via two competing reaction pathways, A and B. In the case of
PhSiH3 pathway A is favored, yielding the linear product A1.
The ring closure pathway (A2) to give silacycloheptane was
not observed. In contrast to the reaction with PhSiH3, intramo-
lecular insertion of the yttrium 5-hexenyl complex leads to the
yttrium methylcyclopentyl complex in the presence of nBuSiH3,
which undergoes intermolecular σ-bond metathesis with
nBuSiH3 to yield (silylmethyl)cyclopentane. This distinctly
different reactivity of PhSiH3 and nBuSiH3 can be rationalized
by the slower attack on the 1-hexenyl yttrium species by the
bulkier nBuSiH3. In addition, intramolecular (labile) coordination
of the dangling double bond at the Lewis acidic yttrium center
may play a role.17c
(19) (a) Zambelli, A.; Longo, P.; Pellecchia, C.; Grassi, A. Macromol-
ecules 1987, 20, 2037. (b) Burger, B. J.; Santarsiero, B. D.; Trimmer, M. S.;
Bercaw, J. E. J. Am. Chem. Soc. 1988, 110, 3134. (c) Nelson, J. E.; Bercaw,
J. E.; Labinger, J. A. Organometallics 1989, 8, 2484. (d) Lapointe, A. M.;
Rix, F. C.; Brookhart, M. J. Am. Chem. Soc. 1997, 119, 906.
(20) (a) Green, M.; Spencer, J. L.; Stone, F. G. A.; Tsipis, C. A. J. Chem.
Soc., Dalton Trans. 1977, 1519. (b) Itoh, M.; Iwata, K.; Takeuchi, R.;
Kobayashi, M. J. Organomet. Chem. 1991, 420, C5. (c) Kakiuchi, F.;
Nogami, K.; Chatani, N.; Seki, Y.; Murai, S. Organometallics 1993, 12,
4748.

Rare-Earth Metals for Hydrosilylation
Organometallics, Vol. 27, No. 15, 2008 3781
Scheme 6
Scheme 7
Conclusion
Experimental Section
General Procedures. All operations were performed under an
inert atmosphere of argon using standard Schlenk-line or glovebox
techniques. THF, n-pentane, and C6D6 were distilled under argon
from sodium/benzophenone ketyl prior to use. PhSiH3 and nBuSiH3
were dried over sodium. The following compounds were prepared
according to published procedures: [Ln(CH2SiMe3)3(THF)2] (Ln
) Sc, Y, Ho),21 2,2′-thiobis(6-tert-butyl-4-methylphenol) (tb-
mpH2).22 1,3-Dithiapropanediylbis(6-tert-butyl-4-methylphenol) (mt-
bmpH2) and 1,4-dithiabutanediylbis(6-tert-butyl-4-methylphenol)
(etbmpH2) were synthesized according to a modification of the
methods reported in the literature.23 All other chemicals were
commercially available and used after appropriate purification.
NMR spectra were recorded on a Varian Mercury 200 BB (1H,
200.0 MHz), Varian Unity 500 (1H, 499.6 MHz; 13C, 125.6 MHz),
or Bruker DRX 400 spectrometer (1H, 400.1 MHz; 13C, 100.6 MHz)
Following our initial studies on the lutetium (trimethylsilyl)-
methyl and hydrido complexes with tridentate [OSO]-type and
tetradentate [OSSO]-type bis(phenolato) ligands,9 we have now
extended this chemistry to other rare-earth metals. The reaction
of the alkyl complexes with phenylsilane leads to the formation
of the corresponding hydrido complexes, which could be isolated
for lutetium9 and holmium. The catalytic activity of the
scandium and yttrium complexes has been explored in the
hydrosilylation of a variety of aliphatic and aromatic monoole-
fins and 1,5-hexadiene. The hydrosilylation reaction is proposed
to occur via the mechanism generally accepted for d0 systems,
involving fast olefin insertion into a metal-hydride bond,
followed by a slow σ-bond metathesis reaction with a silane.
The yttrium complex was found to be more active than the
scandium analogue. The bis(phenolate) complexes with an
[OSO]-/[OSSO]-type framework exhibits a high regioselective
preference for terminal (1,2) addition in the case of aliphatic
monoolefins and a high preference for internal (2,1) addition
with styrene. The selectivity toward secondary addition in the
hydrosilylation of styrene using phenylsilane is remarkably
higher than that reported for the lanthanum amido complex
[La{N(SiHMe2)2}2{CH(PPh2NSiMe3)2}]5b,c and an yttrium alkyl
complex bearing a bis(silylamido) ligand, [Y(DADMB)-
Me(THF)2],6 and is comparable with the selectivity of
[La{N(SiMe3)2}3].5a The steric characteristics of both olefin and
silane substituents were found to influence the reactivity. The
yttrium catalyst is sufficiently reactive to allow a secondary
silane (Ph2SiH2) to be used in the hydrosilylation of 1-hexene.
An intriguing influence of the nature of a silane on the addition
reaction pathway has been observed for 1,5-hexadiene. With
phenylsilane the linear product is formed with high selectivity,
whereas with n-butylsilane formation of the cyclic product is
observed. This may reflect the fact that the rate constant for the
hydrosilylation of the 5-hexenyl intermediate is significantly
decreased for the bulkier n-butylsilane.
1
at 25 °C unless otherwise stated. Chemical shifts for H and 13C
NMR spectra were referenced internally using the residual solvent
resonances and reported relative to tetramethylsilane. Elemental
analyses were performed by the Microanalytical Laboratory of this
department. In some cases the results were not satisfactory and the
best values from repeated runs were given. In the context of
organometallic rare-earth metal compounds, this difficulty was also
observed by other groups and may be ascribed to the formation of
inert carbides.24 Metal analyses were performed by complexometric
titration.25 The sample (15-30 mg) was dissolved in THF (2 mL)
or acetonitrile (2 mL) and titrated with a 0.005 M aqueous solution
of EDTA using xylenol orange as indicator and a 1 M ammonium
(21) (a) Lappert, M. F.; Pearce, R. J. Chem. Soc., Dalton Trans. 1973,
126. (b) Schumann, H.; Mu¨ller, J. J. Organomet. Chem. 1979, 169, C1.
(22) (a) Prakasha, T. K.; Day, R. O.; Holmes, R. R. J. Am. Chem. Soc.
1993, 115, 2690. (b) Fokken, S.; Spaniol, T. P.; Kang, H.-W.; Massa, W.;
Okuda, J. Organometallics 1996, 15, 5069.
(23) Capacchione, C.; Proto, A.; Ebeling, H.; Mu¨lhaupt, R.; Mo¨ller, K.;
Spaniol, T. P.; Okuda, J. J. Am. Chem. Soc. 2003, 125, 4964.
(24) (a) Mitchell, J. P.; Hajela, S.; Brookhart, S. K.; Hardcastle, K. I.;
Henling, L. M.; Bercaw, J. E. J. Am. Chem. Soc. 1996, 118, 1045. (b)
Bambirra, S.; Brandsma, M. J. R.; Brussee, E. A. C.; Meetsma, A.; Hessen,
B.; Teuben, J. H. Organometallics 2000, 19, 3197.
(25) Das, B.; Shome, S. C. Anal. Chim. Acta 1971, 56, 483.

3782 Organometallics, Vol. 27, No. 15, 2008
Konkol et al.
acetate buffer solution (20 mL). The GC/MS(EI) experiments were
run on a Varian VF-5ms spectrometer.
7.08 (m, 2H, 5-C6H2). 1H NMR (400.1 MHz, C6D6): δ 0.05 (s,
2H, ScCH2), 0.53 (s, 9H, SiMe3), 1.19 (br s, 4H, THF), 1.66 (s,
18H, CMe3), 2.11 (s, 6H, Me), 3.72 (br s, 4H, R-H, THF), 7.10 (d,
4JHH ) 2.3 Hz, 2H, 3-C6H2), 7.20 (m, 2H, 5-C6H2). 13C{1H} NMR
(100.6 MHz, THF-d8): δ 4.1 (SiMe3), 20.8 (Me), 26.4 (THF), 30.1
(CMe3), 35.8 (CMe3), 68.2 (THF), 124.8 (4-C6H2), 127.2 (2-C6H2),
129.8 (3-C6H2), 133.4 (5-C6H2), 137.9 (6-C6H2), 165.6 (1-C6H2);
the ScCH2 resonance was not observed. Anal. Calcd for
C34H55O4SScSi (n ) 2) (632.92): Sc, 7.10. Found: Sc, 7.50.
[Sc(etbmp)(CH2SiMe3)(THF)] (5). A solution of [Sc(CH2Si-
Me3)3(THF)3] (0.100 g, 0.222 mmol) in pentane (3 mL) was added
dropwise to a suspension of 1,4-dithiabutanediylbis(6-tert-butyl-
4-methylphenol) (etbmpH2; 0.093 g, 0.222 mmol) in pentane (1
mL). After a while a colorless solution formed that was stirred at
room temperature for 2 h. Upon storage of the solution overnight
at -40 °C colorless crystals of 5 formed that were filtered, washed
with pentane, and dried (0.085 g, 62%). 1H NMR (400.1 MHz,
THF-d8): δ -0.17 (s, 9H, SiMe3), -0.11 (br s, 2H, ScCH2), 1.47
(s, 18H, CMe3), 1.77 (m, 4H, ꢀ-H, THF), 2.16 (s, 6H, Me), 2.67
(v br, 4H, SCH2), 3.62 (m, 4H, R-H, THF), 6.98 (m, 4H, 3-/5-
C6H2). 13C{1H} NMR (100.6 MHz, THF-d8): δ 3.6 (SiMe3), 20.8
(Me), 26.4 (THF), 29.9 (CMe3), 34.8 (br, ScCH2), 35.7 (CMe3),
37.5 (SCH2), 68.2 (THF), 118.6 (2-C6H2), 126.2 (4-C6H2), 130.3,
132.4 (3-/5-C6H2), 138.0 (6-C6H2), 167.1 (1-C6H2). Anal. Calcd
for C32H51O3S2ScSi (620.93): C, 61.90; H, 8.28; Sc, 7.24. Found:
C, 62.46; H, 8.10; Sc, 7.90.
[Y(tbmp)(CH2SiMe3)(THF)n] (1; n ) 1, 2). To a solution of
[Y(CH2SiMe3)3(THF)2.4] (0.219 g, 0.418 mmol) in pentane (3 mL)
was added a solution of thiobis(6-tert-butyl-4-methylphenol) (tb-
mpH2; 0.150 g, 0.418 mmol) in pentane (2 mL) at room temperature
with stirring. Within 1 h a pale yellowish precipitate formed. The
supernatant was decanted, and the precipitate was washed with
pentane and dried. 1 was isolated as an off-white powder upon
1
recrystallization from THF/pentane (0.100 g, 35% for n ) 2). H
2
NMR (400.1 MHz, THF-d8): δ -0.84 (d, JYH ) 3.0 Hz, 2H,
YCH2), -0.03 (s, 9H, SiMe3), 1.38 (s, 18H, CMe3), 1.77 (m, ꢀ-H,
4
THF), 2.12 (s, 6H, Me), 3.62 (m, R-H, THF), 6.84 (d, JHH ) 2.3
4
Hz, 2H, 3-C6H2), 7.20 (d, JHH ) 2.3 Hz, 2H, 5-C6H2). 13C{1H}
NMR (100.6 MHz, THF-d8): δ 4.6 (SiMe3), 20.8 (Me), 24.8 (d,
1JYC ) 45.1 Hz, YCH2), 26.4 (THF), 30.2 (CMe3), 35.8 (CMe3),
68.2 (THF), 124.0 (4-C6H2), 126.6 (2-C6H2), 129.4 (3-C6H2), 133.9
(5-C6H2), 137.8 (6-C6H2), 166.0 (d, 2JYC ) 3.5 Hz, 1-C6H2). Anal.
Calcd for C34H55O4SSiY (n ) 2) (676.86): Y, 13.13. Found: Y,
12.84.
[Y(etbmp)(CH2SiMe3)(THF)n] (2; n ) 1, 2). A solution of
[Y(CH2SiMe3)3(THF)3] (0.200 g, 0.353 mmol) in pentane (3 mL)
was added dropwise to a solution of 1,4-dithiabutanediylbis(6-tert-
butyl-4-methylphenol) (etbmpH2; 0.148 g, 0.353 mmol) in THF (1
mL). The reaction mixture was stirred at room temperature for 2 h,
and then pentane (2 mL) was added. Upon storage overnight at
-40 °C a white precipitate of 2 formed. The supernatant was
decanted, and the precipitate was washed with pentane and dried
(0.185 g, 71% for n ) 2). 1H NMR (400.1 MHz, THF-d8): δ -0.94
(d, 2JYH ) 3.0 Hz, 2H, YCH2), -0.08 (s, 9H, SiMe3), 1.44 (s, 18H,
CMe3), 1.77 (m, ꢀ-H, THF), 2.13 (s, 6H, Me), 2.75 (s, 4H, SCH2),
[Y(etbmp)(CH2SiMe3)(NC5H5)n] (6; n ) 1, 2). Pyridine (0.030
g, 30 µL, 0.375 mmol) was slowly added to a suspension of 2 (0.070
g, 0.095 mmol) in pentane (3 mL). The reaction mixture was stirred
for 1 h at room temperature until the suspension turned pink. Upon
storage of the suspension overnight at -40 °C 6 was isolated as a
pink powder (0.04 g, 56% for n ) 2). 1H NMR (400.1 MHz, C6D6):
δ -0.26 (d, 2JYH ) 3.2 Hz, 2H, YCH2), 0.17 (s, 9H, SiMe3), 1.83
(s, 18H, CMe3), 2.16 (s, 6H, Me), 2.46 (s, 4H, SCH2), 6.54 (m,
4H, 3-/5-H, py), 6.76 (“t”, 2H, 4-H, py), 6.92 (m, 2H, 3-/5-C6H2),
3.62 (m, R-H, THF), 6.92 (m, 4H, 3-/5-C6H2). 13C{1H} NMR
1
(100.6 MHz, THF-d8): δ 4.8 (SiMe3), 20.7 (Me), 21.8 (d, JYC
)
41.6 Hz, YCH2), 26.4 (THF), 30.2 (CMe3), 35.7 (CMe3), 36.7
(SCH2), 68.2 (THF), 119.8 (2-C6H2), 124.6 (4-C6H2), 129.2, 132.3
2
(3-/5-C6H2), 138.3 (6-C6H2), 166.6 (d, JYC ) 3.5 Hz, 1-C6H2).
7.25 (m, 2H, 3-/5-C6H2), 8.89 (br s, 4H, 2-/6-H, py). 13C{1H} NMR
1
Anal. Calcd for C36H59O4S2SiY (n ) 2) (736.98): C, 58.67; H, 8.07;
Y, 12.06. Found: C, 58.46; H, 7.70; Y, 11.82.
(100.6 MHz, THF-d8): δ 4.8 (SiMe3), 20.8 (Me), 22.0 (d, JYC
)
41.6 Hz, YCH2), 30.2 (CMe3), 35.7 (CMe3), 36.7 (SCH2), 119.8
(2-C6H2), 124.3 (3-/5-C, py), 124.6 (4-C6H2), 129.3, 132.3 (3-/5-
C6H2), 136.3 (4-C, py), 138.3 (6-C6H2), 150.7 (2-/6-C, py), 166.6
[Y(mtbmp)(CH2SiMe3)(THF)] (3). A solution of [Y(CH2-
SiMe3)3(THF)3] (0.200 g, 0.353 mmol) in pentane (3 mL) was added
dropwise to 1,3-dithiapropanediylbis(6-tert-butyl-4-methylphenol)
(mtbmpH2; 0.143 g, 0.353 mmol) in THF (0.5 mL). The reaction
mixture was stirred at room temperature for 1 h, and then pentane
(2 mL) was added. Upon storage overnight at -40 °C a white
precipitate of 3 formed. The supernatant was decanted, and the
precipitate was washed with pentane and dried (0.152 g, 66%). 1H
2
(d, JYC ) 3.5 Hz, 1-C6H2). Anal. Calcd for C38H53N2O2S2SiY (n
) 2) (750.97): C, 60.78; H, 7.11; N, 3.73; Y, 11.84. Found: C,
58.34; H, 7.03; N, 3.38; Y, 11.71.
[Lu(mtbmp)(CH2SiMe3)(THF)n] (7; n ) 1, 2). A solution of
[Lu(CH2SiMe3)3(THF)2] (0.200 g, 0.344 mmol) in pentane (3 mL)
was added dropwise to 1,3-dithiapropanediylbis(6-tert-butyl-4-
methylphenol) (mtbmpH2; 0.139 g, 0.344 mmol) in pentane (1 mL).
The reaction mixture was stirred at room temperature for 2 h. Within
that time a white precipitate of 7 formed. Upon storage overnight
at -40 °C the supernatant was decanted and the precipitate was
washed with pentane and dried (0.171 g, 61% for n ) 2). 1H NMR
(400.1 MHz, THF-d8): δ -0.95 (s, 2H, LuCH2), -0.03 (s, 9H,
SiMe3), 1.48 (s, 18H, CMe3), 1.77 (m, ꢀ-H, THF), 2.14 (s, 6H,
Me), 3.62 (m, R-H, THF), 4.04 (s, 2H, SCH2), 6.98 (m, 4H, 3-/5-
C6H2). 13C{1H} NMR (100.6 MHz, THF-d8): δ 4.6 (SiMe3), 20.6
(Me), 26.4 (THF), 29.2 (LuCH2), 30.6 (CMe3), 35.9 (CMe3), 49.5
(SCH2), 68.2 (THF), 123.9 (2-C6H2), 124.8 (4-C6H2), 130.4, 134.5
(3-/5-C6H2), 139.2 (6-C6H2), 166.3 (1-C6H2). Anal. Calcd for
C35H57LuO4S2Si (n ) 2) (809.02): C, 51.96; H, 7.10; Lu, 21.63.
Found: C, 51.55; H, 7.59; Lu, 21.61.
[Lu2(etbmp)3(THF)2] (8). A solution of [Lu(CH2SiMe3)3(THF)2]
(0.100 g, 0.172 mmol) in pentane (3 mL) was added dropwise to
1,4-dithiabutanediylbis(6-tert-butyl-4-methylphenol) (etbmpH2; 0.151
g, 0.361 mmol) in THF (0.3 mL) at room temperature with stirring.
The reaction mixture was stirred at room temperature for 3 h. Upon
storage overnight at -40 °C a white precipitate of 8 formed. The
supernatant was decanted, and the precipitate was washed with
2
NMR (400.1 MHz, THF-d8): δ -0.85 (d, JYH ) 3.5 Hz, 2H,
YCH2), -0.04 (s, 9H, SiMe3), 1.48 (s, 18H, CMe3), 1.77 (m, 4H,
ꢀ-H, THF), 2.14 (s, 6H, Me), 3.62 (m, 4H, R-H, THF), 4.02 (s,
2H, SCH2), 6.98 (m, 4H, 3-/5-C6H2). 13C{1H} NMR (100.6 MHz,
THF-d8): δ 4.5 (SiMe3), 20.6 (Me), 24.5 (d, 1JYC ) 44.2 Hz, YCH2),
26.4 (THF), 30.4 (CMe3), 35.9 (CMe3), 50.1 (SCH2), 68.2 (THF),
124.2 (2-C6H2), 124.8 (4-C6H2), 130.5, 134.4 (3-/5-C6H2), 138.7
2
(6-C6H2), 165.6 (d, JYC ) 3.5 Hz, 1-C6H2). Anal. Calcd for
C31H49O3S2SiY (650.85): C, 57.21; H, 7.59; Y, 13.66. Found: C,
57.14; H, 8.11; Y, 13.52.
[Sc(tbmp)(CH2SiMe3)(THF)n] (4; n ) 1, 2). To a solution of
[Sc(CH2SiMe3)3(THF)2] (0.100 g, 0.222 mmol) in pentane (3 mL)
was added a solution of thiobis(6-tert-butyl-4-methylphenol) (tb-
mpH2; 0.080 g, 0.222 mmol) in THF (0.5 mL) at room temperature
with stirring. After 1 h of stirring solvents were removed in vacuo
and pentane was added (3 mL). Upon storage overnight at -40 °C
a yellowish precipitate of 4 formed. The supernatant was decanted,
and the precipitate was washed with pentane and dried (0.05 g,
36% for n ) 2). 1H NMR (400.1 MHz, THF-d8): δ -0.29 (s, 2H,
ScCH2), -0.03 (s, 9H, SiMe3), 1.39 (s, 18H, CMe3), 1.77 (m, ꢀ-H,
THF), 2.10 (s, 6H, Me), 3.62 (m, R-H, THF), 6.85 (m, 2H, 3-C6H2),

Rare-Earth Metals for Hydrosilylation
Organometallics, Vol. 27, No. 15, 2008 3783
pentane and dried (0.075 g, 50%). Single crystals of 8 suitable for
X-ray diffraction studies were obtained in a decomposition reaction
of the hydrido complex [Lu(etbmp)(µ-H)(THF)]29 in THF/pentane
Typical Hydrosilylation Procedure. In a glovebox a precatalyst
(2, 0.0136 mmol; 4/5, 0.0160 mmol) and C6D6 (0.6 mL) were
introduced into a J. Young NMR tube equipped with a Teflon screw
cap, and then silane (0.558 mmol) and the appropriate alkene or
diene (0.544 mmol) were added by microsyringe. The tube was
shaken vigorously, and the homogeneous reaction mixture was
maintained at 25, 50, or 60 °C using a water bath. The reaction
was monitored by 1H and 13C NMR spectroscopy. The ratio of
Markovnikov and anti-Markovnikov regioisomers was calculated
by integration of the appropriate signals (in most cases SiH2) in
the 1H NMR spectra. In the case of kinetic studies on the
disappearance of 1-hexene with time a 10-fold excess of PhSiH3
was used and the 1H NMR spectra were recorded at 23 °C at regular
10 min intervals for 10 h.
1
solution at -40 °C. H NMR (400.1 MHz, THF-d8): δ 1.37 (s, 3
× 18H, CMe3), 1.77 (m, 2 × 4H, ꢀ-H, THF), 2.19 (s, 3 × 6H,
Me), 2.78 (s, 3 × 4H, SCH2), 3.62 (m, 2 × 4H, R-H, THF), 7.06
(m, 3 × 4H, 3-/5-C6H2). 13C{1H} NMR (100.6 MHz, THF-d8): δ
20.7 (Me), 26.4 (THF), 29.9 (CMe3), 35.6 (CMe3), 36.5 (SCH2),
68.2 (THF), 119.5 (2-C6H2), 129.3 (4-C6H2), 129.9, 134.5 (3-/5-
C6H2), 136.7 (6-C6H2), 154.8 (1-C6H2). Anal. Calcd for
C80H112Lu2O8S6 (1744.10): C, 55.09; H, 6.47; Lu, 20.06. Found:
C, 55.31; H, 6.72; Lu, 19.79.
[Ho(tbmp)(CH2SiMe3)(THF)2](9).Asolutionof[Ho(CH2SiMe3)3-
(THF)2] (0.165 g, 0.289 mmol) in pentane (5 mL) was added
dropwise to a solution of thiobis(6-tert-butyl-4-methylphenol)
(tbmpH2; 0.104 g, 0.289 mmol) in pentane (5 mL) at room
temperature with stirring. The resulting yellow-orange solution was
stirred for 1 h, and upon storage overnight at -40 °C a yellow
precipitate of 9 formed. The supernatant was decanted, and the
precipitate was washed with pentane and dried (0.085 g, 39%). Anal.
Calcd for C34H55HoO4SSi (752.89): C, 54.24; H, 7.36; Ho, 21.91.
Found: C, 55.03; H, 6.87; Ho, 21.84.
[Ho(etbmp)(CH2SiMe3)(THF)](10).Asolutionof[Ho(CH2SiMe3)3-
(THF)2] (0.165 g, 0.289 mmol) in pentane (3 mL) was added
dropwise to a suspension of 1,4-dithiabutanediylbis(6-tert-butyl-
4-methylphenol) (etbmpH2; 0.121 g, 0.289 mmol) in pentane (3
mL) at room temperature with stirring. The resulting pink solution
was stirred for 1 h, and upon storage overnight at -40 °C a pink
precipitate of 10 formed. The supernatant was decanted, and the
precipitate was washed with pentane and dried (0.104 g, 48%). Anal.
Calcd for C32H51HoO3S2Si (740.90): C, 51.88; H, 6.94; Ho, 22.26.
Found: C, 53.16; H, 6.70; Ho, 22.06.
NMR Data of Selected Hydrosilylation Products. 1-Hexyl-
phenylsilane. 1H NMR (400.1 MHz, C6D6): δ 0.75-0.81 (m, 2H,
CH2Si), 0.83 (t, 3JHH ) 7.0 Hz, 3H, CH3), 1.07-1.29 (m, 6H, CH2),
3
1.30-1.43 (m, 2H, CH2), 4.46 (t, JHH ) 3.7 Hz, 2H, SiH2),
7.09-7.17 (m, 3H, Ph), 7.44-7.51 (m, 2H, Ph). 13C{1H} NMR
(100.6 MHz, C6D6): δ 10.4 (CH2Si), 14.3 (CH3), 22.9 (CH2), 25.4
(CH2), 31.8 (CH2), 32.9 (CH2), 128.3 (m-C, Ph), 129.8 (p-C, Ph),
132.9 (i-C, Ph), 135.5 (o-C, Ph).
1-Butyl-1-hexylsilane. 1H NMR (400.1 MHz, C6D6): δ 0.57-0.71
(m, 4H, CH2Si), 0.87 (t, 3JHH ) 7.0 Hz, CH3), 0.90 (t, 3JHH ) 7.0
3
Hz, CH3), 1.16-1.47 (m, 12H, CH2), 5.10 (qn, JHH ) 3.7 Hz,
2H, SiH2). 13C{1H} NMR (100.6 MHz, C6D6): δ 9.2 (CH2Si), 9.5
(CH2Si), 14.0 (CH3), 14.3 (CH3), 23.0 (CH2), 25.9 (CH2), 26.3
(CH2), 28.1 (CH2), 31.9 (CH2), 33.0 (CH2).
(3,3-Dimethyl-1-butyl)phenylsilane. 1H NMR (400.1 MHz,
C6D6): δ 0.70-0.76 (m, 2H, CH2Si), 0.77 (s, 9H, CH3), 1.23-1.30
3
(m, 2H, CH2), 4.46 (t, JHH ) 3.7 Hz, 2H, SiH2). 13C{1H} NMR
[Ho(tbmp)(µ-H)(THF)3]2 (11). A solution of [Ho(CH2SiMe3)3-
(THF)2] (0.215 g, 0.376 mmol) in pentane (2 mL) was added
dropwise to a solution of thiobis(6-tert-butyl-4-methylphenol)
(tbmpH2; 0.134 g, 0.374 mmol) in pentane (3 mL) at room
temperature with stirring. After 10 min an orange-pink suspension
was observed. After 30 min PhSiH3 was added (0.26 mL, 2.08
mmol) and the reaction mixture was stirred for a further 2 h. Upon
storage overnight at -40 °C a pink precipitate of 11 formed. The
supernatant was decanted, and the precipitate was washed with a
small amount of pentane and dried (0.092 g, 33%). Anal. Calcd
for C34H53HoO5S (738.79): C, 55.28; H, 7.23; Ho, 22.32. Found:
C, 55.10; H, 7.36; Ho, 21.79.
[Ho(etbmp)(µ-H)(THF)2]2 (12). A solution of [Ho(CH2SiMe3)3-
(THF)2] (0.250 g, 0.438 mmol) in pentane (5 mL) was added
dropwise to 1,4-dithiabutanediylbis(6-tert-butyl-4-methylphenol)
(etbmpH2; 0.183 g, 0.437 mmol) in pentane (5 mL) at room
temperature with stirring. After 30 min PhSiH3 was added (0.3 mL,
2.43 mmol) and the reaction mixture was stirred for a further 1 h.
A pink precipitate started to deposit after a few minutes. Upon
storage overnight at -40 °C the supernatant was decanted and the
precipitate of 12 was washed with a small amount of pentane and
dried (0.135 g, 42%). Anal. Calcd for C32H49HoO4S2 (726.80): C,
52.88; H, 6.79; Ho, 22.69. Found: C, 52.26; H, 6.85; Ho, 22.04.
(100.6 MHz, C6D6): δ 4.8 (CH2Si), 28.8 (CH3), 31.3 (C), 39.4
(CH2), 128.3 (m-C, Ph), 129.8 (p-C, Ph), 132.8 (i-C, Ph), 135.5
(o-C, Ph).
1-Butyl(3,3-dimethyl-1-butyl)silane. 1H NMR (400.1 MHz,
C6D6): δ 0.53-0.60 (m, 2H, CH2Si), 0.60-0.67 (m, 2H, CH2Si),
0.85 (s, 9H, CH3), 0.87 (t, 3JHH ) 7.1 Hz, 3H, CH2CH3), 1.24-1.30
3
(m, 2H, CCH2), 1.30-1.40 (m, 4H, CH2), 3.91 (qn, JHH ) 3.7
Hz, 2H, SiH2). 13C{1H} NMR (100.6 MHz, C6D6): δ 3.9 (t-
BuCH2CH2Si), 9.1 (CH2Si), 14.0 (CH2CH3), 26.3 (CH2), 28.0
(CH2), 28.9 (CH3), 31.3 (C), 40.0 (CH2C).
(4,4-Dimethyl-1-pentyl)phenylsilane. 1H NMR (400.1 MHz,
C6D6): δ 0.75-0.79 (m, 2H, CH2Si), 0.79 (s, 9H, CH3), 1.13-1.21
3
(m, 2H, CH2), 1.32-1.42 (m, 2H, CH2), 4.48 (t, JHH ) 3.8 Hz,
2H, SiH2), 7.11-7.16 (m, 3H, Ph), 7.45-7.52 (m, 2H, Ph). 13C{1H}
NMR (100.6 MHz, C6D6): δ 11.1 (CH2Si), 20.4 (CH2), 29.5 (CH3),
30.5 (C), 47.9 (CH2), 128.3 (m-C, Ph), 129.8 (p-C, Ph), 132.8 (i-
C, Ph), 135.5 (o-C, Ph).
(4,4-Dimethyl-2-pentyl)phenylsilane. 1H NMR (400.1 MHz,
C6D6): δ 1.05-1.09 (m, 4H, CH3 + CH), 4.36-4.42 (m, 2H, SiH2);
other signals could not be assigned due to overlapping. 13C{1H}
NMR (100.6 MHz, C6D6): δ 12.0 (CH), 19.2 (CH3), 29.8 (CMe3),
47.2 (CH2), 128.4 (m-C, Ph), 130.1 (p-C, Ph), 132.6 (i-C, Ph), 135.2
(o-C, Ph); C resonance could not be assigned.
Reaction of [Y(tbmp)(CH2SiMe3)(THF)] (1) with PhSiH3.
PhSiH3 (20 µL, 160 µmol) was added at room temperature to a
solution of 1 (0.025 g, 43 µmol) in C6D6. The reaction was
monitored by NMR spectroscopy. The 1H NMR spectrum after 15
min showed, besides other products, the formation of the hydrido
complex 13. 1H NMR (400.1 MHz, C6D6): δ 1.36 (s, 18H, CMe3),
1.75 (br s, 4H, ꢀ-H, THF), 2.10 (s, 6H, Me), 3.61 (br s, 4H, R-H,
2-Cyclohexyl-1-(phenylsilyl)ethane. 1H NMR (400.1 MHz,
C6D6): δ 0.66-0.83 (m, 4H, CH2Si + CH2), 0.99-1.20 (m, 5H,
CH + 2 × CH2), 1.22-1.32 (m, 2H, CH2), 1.54-1.67 (m, 4H,
3
CH2), 4.46 (t, JHH ) 3.8 Hz, 2H, SiH2), 7.10-7.17 (m, 3H, Ph),
7.44-7.53 (m, 2H, Ph). 13C{1H} NMR (100.6 MHz, C6D6): δ 7.5
(CH2Si), 26.7 (CH2), 27.0 (CH2), 32.9 (CH2), 33.1 (CH2), 40.5 (CH),
128.3 (m-C, Ph), 129.8 (p-C, Ph), 132.9 (i-C, Ph), 135.5 (o-C, Ph).
1-(Phenylsilyl)-2-(trimethylsilyl)ethane. 1H NMR (400.1 MHz,
C6D6): δ -0.07 (s, 9H, CH3), 0.48-0.55 (m, 2H, H2SiCH2),
0.71-0.79 (m, 2H, CH2SiMe3), 4.51 (t, 3JHH ) 3.7 Hz, 2H, SiH2),
7.14-7.18 (m, 3H, Ph), 7.49-7.54 (m, 2H, Ph). 13C{1H} NMR
THF), 6.80 (br s, 2H, 3-C6H2), 7.07 (t, 1JYH ) 27.5 Hz, 1H, YHY),
4
7.15 (d, JHH
) 2.4 Hz, 2H, 5-C6H2); other products
(PhSiH2CH2SiMe3) and educts (PhSiH3):, 0.03 (s, 9H, SiMe3), 0.12
(t, JHH ) 4.6 Hz, 2H, SiCH2Si), 4.15 (s, 3H, SiH3), 4.35 (t, JHH
) 4.6 Hz, 2H, SiH2), 7.32, 7.56 (m, Ph).
3
3

3784 Organometallics, Vol. 27, No. 15, 2008
Konkol et al.
Table 4. Experimental Data for the Crystal Structure Determination of the Complexes 5, 7 · 2THF, and 8 · 2C5H10
5
7 · 2THF
8 · 2C5H10
empirical formula
Mr
C32H51O3S2ScSi
620.90
C43H71LuO6S2Si
951.18
C45H68LuO4S3
944.20
cryst size/mm
cryst syst
space group
0.18 × 0.18 × 0.08
orthorhombic
Pbca
0.48 × 0.42 × 0.16
monoclinic
P21/c
0.13 × 0.12 × 0.04
monoclinic
C2/c
a/Å
b/Å
c/Å
10.604(17)
17.30(2)
38.19(5)
90
7006(17)
8
1.177
0.392
2672
13.4712(12)
27.631(3)
13.4928(12)
114.6650(10)
4564.2(7)
4
1.384
2.323
1976
13.2096(13)
26.185(3)
27.025(3)
96.358(2)
9290.3(17)
8
1.350
2.298
3911
ꢀ/deg
U/Å3
Z
Dc/g cm-3
µ(Mo KR)/mm-1
F(000)
T/K
θ range/deg
130(2)
2.13-26.41
79 142
110(2)
2.22-30.86
67 539
130(2)
2.17-28.34
33 675
no. of rflns collected
no. of rflns obsd (I > 2σ(I))
3498
11 617
8871
no. of indep rflns (Rint
)
7187 (0.1969)
7187/6/356
1.007
0.0705, 0.1091
0.1459, 0.1260
0.447, -0.332
13 463 (0.0390)
13 463/96/478
1.093
0.0364, 0.0948
0.0452, 0.1001
2.222, -1.016
11 464 (0.0907)
11 464/5/453
1.161
0.0762, 0.1516
0.1031, 0.1623
1.744, -3.013
no. of data/restraints/params
GOF
final R indices R1,a wR2b (obsd data)
final R indices R1, wR2 (all data)
largest e(max), e(min)/e Å-3
2
2 2
a R1(F) ) ∑||Fo| - |Fc||/∑|Fo|. b wR2(F) ) [∑w(Fo - Fc ) /∑w(Fo2)2]1/2
.
(100.6 MHz, C6D6): δ -2.1 (CH3), 3.0 (CH2SiMe3), 10.8
(H2SiCH2), 128.3 (m-C, Ph), 129.8 (p-C, Ph), 133.0 (i-C, Ph), 135.5
(o-C, Ph).
132.8 (i-C, Ph), 135.5 (o-C, Ph). MS m/z (rel. int.): 220.2 (M-C6H6,
30), 142 (M-2 × C6H6, 100), 114 (56), 111 (22), 107 (PhSiH2,
98), 106 (27), 105 (43), 85 (20).
(Phenylsilylmethyl)cyclopentane. 1H NMR (400.1 MHz, C6D6):
δ 0.88 (dt, J ) 7.3 Hz, 3.8 Hz, 2H, CH2Si), 0.99-1.05 (m, 2H,
CH2), 1.33-1.55 (m, 4H, CH2), 1.66-1.86 (m, 3H, CH+CH2), 4.47
1-(Phenylsilyl)-1-(trimethylsilyl)ethane. 1H NMR (400.1 MHz,
C6D6): δ 0.01 (s, 9H, CH3), 0.09-0.16 (m, 1H, CH), 1.05 (d, 3JHH
) 7.5 Hz, 3H, CH3), 4.41-4.45 (m, 1H, SiH), 4.56-4.59 (m, 1H,
SiH), 7.14-7.18 (m, 3H, Ph), 7.49-7.54 (m, 2H, Ph). 13C{1H}
NMR (100.6 MHz, C6D6): δ -1.8 (CH3), 2.4 (CH), 10.7 (CH3CH),
128.3 (m-C, Ph), 129.7 (p-C, Ph), 133.2 (i-C, Ph), 135.8 (o-C, Ph).
1-Phenyl-1-(phenylsilyl)ethane. 1H NMR (400.1 MHz, C6D6):
δ 1.30 (d, 3JHH ) 7.5 Hz, 3H, CH3), 2.34-2.42 (m, 1H, CH), 4.44
(m, 2H, SiH2), 6.95-6.99 (m, 2H, Ph), 7.02-7.13 (m, 6H, Ph),
7.28-7.31 (m, 2H, Ph). 13C{1H} NMR (100.6 MHz, C6D6): δ 16.5
(CH3), 25.6 (CH), 125.4 (Ph), 127.4 (Ph), 128.1 (Ph), 128.7 (Ph),
130.0 (Ph), 131.6 (i-C, Ph), 136.0 (Ph), 144.6 (i-C, Ph).
3-Phenyl-1-(phenylsilyl)propane. 1H NMR (400.1 MHz, C6D6):
δ 0.72-0.78 (m, 2H, CH2Si), 1.58-1.66 (m, 2H, CH2), 2.44 (t,
3
(t, JHH ) 3.8 Hz, 2H, SiH2), 7.11-7.17 (m, Ph), 7.43-7.51 (m,
Ph). 13C{1H} (100.6 MHz, C6D6): δ 17.2 (CH2Si), 25.4 (CH2), 35.7
(CH2), 37.2 (CH), 128.4 (m-C, Ph), 129.7 (p-C, Ph), 133.1 (i-C,
Ph), 135.5 (o-C, Ph).
X-ray Crystal Structure Determination. Relevant crystal-
lographic data are summarized in Table 4. The X-ray diffraction
data of the complexes 5, 7, and 8 were collected on a Bruker AXS
diffractometer with a CCD area detector with Mo KR radiation
(graphite monochromator, λ ) 0.710 73 Å) using λ scans. The
SMART program package was used for the data collection and
unit cell determination; processing of the raw frame data was
performed using SAINT.26 The structures were solved by direct
methods using the SHELXS-97 program27 and refined against F2
using all reflections with the SHELXL-97 software.28 The hydrogen
atoms were placed in calculated positions. The twist disorder of
the coordinated THF molecule in 5 was modeled to a split
occupancy of 0.53/0.47. All carbon atoms in the molecule of THF
were treated as isotropic in refinement. Two pentane molecules in
the structure of 8 were solved as isotropic in refinement.
3
3JHH ) 7.6 Hz, 2H, CH2), 4.42 (t, JHH ) 3.6 Hz, 2H, SiH2),
6.94-6.98 (m, 2H, Ph), 7.00-7.15 (m, 6H, Ph), 7.40-7.44 (m,
2H, Ph). 13C{1H} NMR (100.6 MHz, C6D6): δ 9.9 (CH2Si), 27.3
(CH2), 39.2 (CH2), 126.1 (Ph), 128.3 (Ph), 128.6 (Ph), 128.8 (Ph),
129.8 (Ph), 132.6 (i-C, Ph), 135.5 (Ph), 142.2 (i-C, Ph).
3-Phenyl-2-(phenylsilyl)propane. 1H NMR (400.1 MHz, C6D6):
3
δ 0.92 (d, JHH ) 7.3 Hz, 3H, CH3), 1.27-1.33 (m, 1H, CH),
2.33-2.39 (m, 1H, CHAHBCH), 2.77-2.82 (m, 1H, CHAHBCH),
4.34-4.40 (m, 2H, SiH2); Ph resonances were not found due to
overlapping. 13C{1H} NMR (100.6 MHz, C6D6): δ 15.7 (CH3), 18.8
(CHSi), 39.7 (CH2), 126.2 (Ph), 128.5 (Ph), 129.2 (Ph), 131.9 (i-
C, Ph), 135.2 (Ph), 141.6 (i-C, Ph); other two Ph signals were not
found.
Acknowledgment. We thank the Deutsche Forschungs-
gemeinschaft and the Fonds der Chemischen Industrie for
financial support and Mr. A. Schroeer for experimental
support.
3-Phenyl-1-(butylsilyl)propane. 1H NMR (400.1 MHz, C6D6):
3
Supporting Information Available: Text and tables giving
X-ray crystal data and additional NMR data and CIF files giving
full crystallographic data for 5, 7, and 8. This material is available
free of charge via the Internet at http://pubs.acs.org.
δ 0.46-0.54 (m, 2 × 2H, CH2Si), 0.77 (t, JHH ) 7.1 Hz, 3H,
CH3), 1.19-1.27 (m, 2 × 2H, CH2), 1.53-1.61 (m, 2H, CH2), 2.44
(t, 3JHH ) 7.6 Hz, 2H, PhCH2), 3.80 (qn, 3JHH ) 3.7 Hz, 2H, SiH2),
6.96-7.02 (m, 3H, Ph), 7.06-7.11 (m, 2H, Ph). 13C{1H} (100.6
MHz, C6D6): δ 9.07 (CH2Si), 9.11 (CH2Si), 13.9 (CH3), 26.2
(CH3CH2), 27.8 (CH2), 28.0 (CH2), 39.4 (PhCH2), 126.1 (p-C, Ph),
128.6/128.8 (o/m-C, Ph), 142.4 (i-C, Ph).
OM800161U
(26) ASTRO, SAINT and SADABS: Data Collection and Processing
Software for the SMART System; Siemens Analytical X-ray Instruments
Inc., Madison, WI, 1996.
(27) Sheldrick, G. M. SHELXS-86: A Program for Crystal Structures;
University of Go¨ttingen, Go¨ttingen, Germany, 1986.
(28) Sheldrick, G. M. SHELXL-97: A Program for Crystal Structure
Refinement; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
1,6-Bis(phenylsilyl)hexane. 1H NMR (400.1 MHz, C6D6): δ 0.76
(m, 4H, CH2Si), 1.14-1.20 (m, 4H, CH2), 1.24-1.36 (m, 4H, CH2),
3
4.45 (t, JHH ) 3.6 Hz, 4H, SiH2), 7.11-7.17 (m, 6H, m-/p-H),
7.43-7.51 (m, 4H, o-H). 13C{1H} (100.6 MHz, C6D6): δ 10.3
(CH2Si), 25.3 (CH2), 32.7 (CH2), 128.3 (m-C, Ph), 129.8 (p-C, Ph),