Synthesis of novel group 4 metallocene-containing silsesquioxanes with a vinyl group

Article abstract of DOI:10.1246/cl.2000.628

Novel zirconocene or hafnocene-containing silsesquioxanes with a vinyl group Cp₂M{[(vinyl)Me₂Si](c-C₅H₉)₇Si₇O₁₂} (Cp = cyclopentadienyl, M = Zr, Hf) were synthesized, as well as a derivative with a trimethylsilyl group Cp₂Zr[(Me₃Si)(c-C₅H₉)₇Si₇O₁₂]. A derivative containing a dimethylethoxysilyl group was also synthesized.

Full text of DOI:10.1246/cl.2000.628

6
28
Chemistry Letters 2000
Synthesis of Novel Group 4 Metallocene-Containing Silsesquioxanes with a Vinyl Group
Kenji Wada, Masaki Bundo, Daisuke Nakabayashi, Naohiko Itayama, Teruyuki Kondo, and Take-aki Mitsudo*
Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Sakyo-ku, Kyoto 606-8501
(Received March 13, 2000; CL-000245)
Novel zirconocene or hafnocene-containing silsesquioxanes
with a vinyl group Cp M{[(vinyl)Me Si](c-C H ) Si O } (Cp =
2
2
5
9 7
7
12
cyclopentadienyl, M = Zr, Hf) were synthesized, as well as a
derivative with a trimethylsilyl group Cp Zr[(Me Si)(c-
2
3
C H ) Si O ]. A derivative containing a dimethylethoxysilyl
5
9 7
7
12
group was also synthesized.
Metal-containing oligosilsesquioxanes have attracted atten-
tion from a view point of well-defined, homogeneous models for
the active surface sites of the supported catalysts or metal-contain-
ing zeolites.1 Especially, recent interests are focused on the cat-
2
alytic activities of titanium-containing silsesquioxanes for epoxi-
3
dation of olefins as soluble analog of titanosilicates. Several tita-
nium or zirconium-containing silsesquioxanes were reported to be
4
active catalysts for olefin polymerization. In addition, these
metal-containing silsesquioxanes were found to be convenient
precursors for porous M-Si-O materials with high surface areas
5
and uniformly-controlled micropores. Therefore development of
novel group 4 metal-containing silsesquioxanes is required. On
the other hand, introduction of appropriate functional groups into
these molecules is of great importance with regard to the develop-
6
ment of novel organic-inorganic hybrid materials.
In the present communication, we report the syntheses of
novel zirconocene or hafnocene-containing silsesquioxanes
with a vinyl group, 3b and 4b, as well as a derivative with a
trimethylsilyl group, 3a. The synthesis of a derivative contain-
ing a dimethylethoxysilyl anchor, 5, from 3b is reported. In
addition, they are good precursors for microporous oxides .
7
8
The reaction of disilanols 2a and 2b, which were prepared
by the kinetically-controlled silylation of a silsesquioxane triol
symmetry of their siloxane backbones.
(
c-C H ) Si O (OH) 1, with zirconocene dichloride in the pres-
The use of hafnocene dichloride in place of zirconocene
dichloride resulted in the formation of a hafnocene-containing
5
9 7
7
9
3
ence of excess triethylamine in chloroform at room temperature
produced zirconocene-containing silsesquioxanes 3a and 3b,
respectively, in high yields. The structures of 3a and 3b were
deduced on the basis of H, C and Si NMR, FAB-MASS, and
exactly confirmed by X-ray analyses.
structure of 3a together with selected bond distances and angles
reported in the caption. The structure around the zirconium atom
is represented by a pseudo-tetrahedron. The Zr-O bond distances
are within the range observed for another zirconium-containing
silsesquioxane with cubic core structure, C Me Zr(c-
9
10
15
silsesquioxane 4b (yield 73%). Analysis of 4b on the basis of
1
13
29
H, C and Si NMR clearly shows its structural resemblance to
1
13
29
3b. On the other hand, the reaction of 2a or 2b with titanocene
dichloride did not produce titanium-containing silsesquioxanes,
and unreacted disilanols were recovered almost quantitatively.
The present result contrasts with the early result by Buys et
al., in which the reaction of a silsesquioxane triol, (c-
C H ) Si O (OH) , with zirconocene or hafnocene dichloride
1
1,12
Figure 1 shows the
6
11 7
7
9
3
resulted in the complete loss of both Cp ligands and produced
5
5
13
16
C H ) Si O (1.958(6) Å). Note that the Si(7)-O(12)-Si(8)
oligomeric species. One of the reasons would be higher reac-
6
11 7
7
12
1
bond angle is very large, 173(1)°, probably due to the steric repul-
sion between the trimethylsilyl group and the cyclopentadienyl
ring. Other bond distances and bond angles are within the range
tivities of silsesquioxane triols than those of disilanols.
The hydrosilylation of a vinyl group in 3b with
Me SiH(OEt) in the presence of a Pt (dvs) catalyst (1 mol% as
2
2
3
expected.1
3,14
The C NMR spectra of 3a and 3b indicate the
presence of two unequivalent Cp rings, and five resonances in a 1
2 : 2 : 1 : 1 ratio for the ipso-carbon atoms in the cyclopentyl
13
Pt, dvs = divinyltetramethyldisiloxane) in toluene at 30 °C for 72
17
h cleanly occurred with excellent regioselectivity to give 5,
a
:
derivative containing a dimethylethoxysilyl group, which would
be a good precursor for the immobilized heterogeneous catalysts.
The other possible regioisomer was not observed even by NMR.
The present metallocene-containing silsesquioxanes are
29
rings. The Si-NMR spectra of both molecules also consist of
five peaks in a 1 : 2 : 1 : 1 : 2 ratio for seven silicon atoms in the
silsesquioxane cage, which are in good accordance with local Cs-
Copyright © 2000 The Chemical Society of Japan

Chemistry Letters 2000
629
2
2
7.24, 27.10, 27.03, 27.01 (CH ), 23.64, 22.79, 22.44, 22.28, 22.20 (1 :
2
2
9
1
: 2 : 1 : 1 for CH), -0.01 (Si(CH ) ); Si{ H} NMR (76 MHz,
3
2
CDCl , 0.02 M Cr(acac) , 25 °C) δ -1.08, -56.70, -65.59, -66.40, -67.46
3
3
(
1 : 2 : 2 : 1 : 2). Anal. Calcd for C H O Si (959.68): C, 48.81; H,
39 74 12 8
7
.77%. Found C, 48.54; H, 7.55%.
9
3a: In a typical experiment, to a solution of 2a (948 mg, 1.0 mmol)
and Cp ZrCl (292 mg, 1.0 mmol) in CHCl (50 cm ), triethylamine
3
2
2
3
3
(1.4 cm , 10 mmol) was added dropwise, and the mixture was stirred
at room temperature for 30 min. The solvent was then evaporated at
room temperature to give an off-white solid. This was extracted with
hexane (60 cm ) to give a clear filtrate and a white residue of triethyl-
5
also found to be precursors for microporous oxides. For exam-
ple, the calcination of 3b in air stream at 823 K for 2 h pro-
duced a Zr-Si-O material with a high BET surface area of 370
3
ammonium chloride. The filtrate was evaporated, and white micro-
crystals of 3a were obtained by the recrystallization by slow diffusion
1
2
-1
of acetonitrile into a CHCl3 solution. Yield 87%. M.p. > 300 °C; H
m g and a Type I isotherm typical for microporous materials.
In conclusion, silsesquioxanes containing both metallocene
moiety and olefinic functionality in their framework, 3b and 4b,
were synthesized, as well as 3a, for the first time. A derivative
with an ethoxysilyl anchor was also synthesized. These mole-
cules would be appropriate model compounds for the silica-
supported metallocene catalysts,1 or precursors for novel
immobilized catalysts or organic-inorganic hybrid materials.
NMR (300 MHz, CDCl , 25 °C) δ 6.32 (s, 5H, C H ), 6.18 (s, 5H,
3
5
5
C H ), 1.77–1.50 (br m, 56H, CH of Cy), 0.97–0.89 (br m, 7H, CH
5
5
2
1
3
1
of Cy), -0.07 (s, 9H, Si(CH ) ); C{ H} NMR (75 MHz, CDCl , 25
3
3
3
°
2
C) δ 113.95, 113.21 (C H ), 27.97, 27.81, 27.71, 27.59, 27.51,
5 5
7.46, 27.33, 27.20, 27.09, 27.06, 27.02, 26.90 (CH ), 24.94, 23.56,
2
2
3.50, 22.73, 22.67 (1 : 2 : 2 : 1 : 1 for CH), 1.82 (Si(CH ) );
3
3
29
1
Si{ H} NMR (76 MHz, CDCl , 0.02 M Cr(acac) , 25 °C) δ 7.66, -
3
3
8
65.29, -65.84, -66.26, -66.33, -67.83 (1 : 1 : 2 : 1 : 1 : 2). MS (FAB)
m/z 1165 [M + H] , 1099 [M - C H ] . Exact mass Found 1165.3068.
Calcd for C H O Si Zr [M + H] : 1165.3086.
+
+
5
5
+
48
83 12
8
1
0
3b: Similar method for 3a was adopted by using 960 mg (1.0 mmol)
1
This work is supported in part by a Grant-in Aid for
Scientific Research (No. 11650807) from the Ministry of
Education, Science, Sports, and Culture.
of 2b in place of 2a. Yield 83%. M.p. > 300 °C; H NMR (300
MHz, CDCl , 25 °C) δ 6.32 (s, 5H, C H ), 6.17 (s, 5H, C H ), 6.00
3
5
5
5
5
3
3
(
dd, J = 20.2 Hz, 14.8 Hz, 1H, SiCH=CH ), 5.81 (dd, J = 14.8 Hz,
J = 4.2 Hz, 1H, cis-SiCH=CH ), 5.61 (dd, J = 20.2 Hz, J = 4.2 Hz,
2
2
3
2
2
1
H, trans-SiCH=CH ), 1.77–1.48 (br m, 56H, CH of Cy), 1.00–0.84
2
2
References and Notes
(br m, 7H, CH of Cy), -0.02 (s, 6H, Si(CH ) ); 13C{1H} NMR (75
3 2
1
2
F. J. Feher and T. A. Budzichowski, Polyhedron, 14, 3239 (1995).
a) M. Crocker, R. H. M. Herold, and A. G. Orpen, Chem. Commun.,
MHz, CDCl , 25 °C) δ 139.42 (SiCH=CH ), 131.36 (SiCH=CH ),
3 2 2
113.98, 113.21 (C H ), 27.99, 27.82, 27.70, 27.60, 27.53, 27.48,
5
5
1
997, 2411. b) M. Crocker, R. H. M. Herold, A. G. Orpen, and M. T.
27.34, 27.20, 27.10, 27.07, 27.02, 26.91 (CH ), 24.86, 23.57, 23.53,
2
Overgaag, J. Chem. Soc., Dalton Trans., 1999, 3791. c) H. C. L.
Abbenhuis, S. Krijnen, and R. A. van Santen, Chem. Commun., 1997,
22.75, 22.69 (1 : 2 : 2 : 1 : 1 for CH), 0.13 (Si(CH ) ); 29Si{1H} NMR
3
2
(76 MHz, CDCl , 0.02 M Cr(acac) , 25 °C) δ -3.55, -65.25, -65.76,
3
3
3
31. d) S. Krijnen, H. C. L. Abbenhuis, R. W. J. M. Hanssen, J. H. C.
van Hooff, and R. A. van Santen, Angew. Chem., Int. Ed. Engl., 37,
56 (1998). e) T. Maschmeyer, M. C. Klunduk, C. M. Martin, D. S.
Shephard, J. M. Thomas, and B. F. G. Johnson, Chem. Commun.,
-66.03, -66.28, -67.76 (1 : 1 : 2 : 1 : 1 : 2). MS (FAB) m/z 1177 [M +
H]+, 1111 [M - C H ]+. Exact mass Found 1177.3070. Calcd for
5
5
3
C H O Si Zr [M + H]+: 1177.3086.
49 83 12 8
11 Crystal data for 3a: C H O Si Zr (FW = 1167.07), monoclinic,
4
8
82 12
8
1
997, 1847. f) M. C. Klunduk, T. Maschmeyer, J. M. Thomas, and B.
P2 /n, a = 13.20(1), b = 20.01(1), c = 23.740(7) Å, β = 104.60(4)°, V
1
F. G. Johnson, Chem. Eur. J., 5, 1481 (1999).
= 6068(6) Å3, T = 23 °C, Z = 4, D
= 1.277 g·cm-3, R = 0.057 (R
=
calcd w
3
4
I. W. C. E. Arends, R. A. Sheldon, M. Wallau, and U. Schuchardt,
Angew. Chem., Int. Ed. Engl., 36, 1144 (1997) and references therein.
a) R. Duchateau, H. C. L. Abbenhuis, R. A. van Santen, A. Meetsma,
S. K. H. Thiele, and M. F. H. van Tol, Organometallics, 17, 5663
0.059), GOF = 0.68 for 1971 observed reflections [I > 3σ(I)].
12 The compound 3b crystallized in the monoclinic space group P2 /n
1
with a cell volume of 6131(5) Å3 (a = 13.336(5), b = 19.83(1), c =
23.98(2) Å, β = 104.71(4)°). The structure of 3b is quite similar to
that of 3a, and a vinyl goup is located at the opposite side of the zir-
conium atom. Poor diffraction prevented a satisfactory solution of
the structure.
(1998). b) R. Duchateau, U. Cremer, R. J. Harmsen, S. I. Mohamud,
H. C. L. Abbenhuis, R. A. van Santen, A. Meetsma, S. K. H. Thiele,
M. F. H. van Tol, and M. Kranenburg, Organometallics, 18, 5447
(1999).
13 F. J. Feher, J. Am. Chem. Soc., 108, 3850 (1986).
14 E. Samuel, J. F. Harrod, M. J. McGlinchey, C. Cabestaing, and F.
5
a) K. Wada, M. Nakashita, M. Bundo, K. Ito, T. Kondo, and T.
Mitsudo, Chem. Lett., 1998, 659. b) N. Maxim, H. C. L. Abbenhuis,
P. J. Stobbelaar, B. L. Mojet, and R. A. van Santen, Phys. Chem.
Chem. Phys., 1, 4473 (1999).
Robert, Inorg. Chem., 33, 1292 (1994).
15 NMR data for 4b: 1H NMR (300 MHz, CDCl , 25 °C) δ 6.28 (s, 5H,
3
C H ), 6.14 (s, 5H, C H ), 6.01 (dd, 3J = 20.2 Hz, 14.8 Hz, 1H,
5
5
5
5
6
7
8
a) F. J. Feher and S. J. Phillips, J. Organomet. Chem., 521, 401
SiCH=CH ), 5.82 (dd, 3J = 14.8 Hz, 2J = 4.2 Hz, 1H, cis-SiCH=CH ),
2
2
(
1
1996). b) F. J. Feher, R. Terroba, and J. W. Ziller, Chem. Commun.,
999, 2153.
5.63 (dd, 3J = 20.2 Hz, 2J = 4.2 Hz, 1H, trans-SiCH=CH ), 1.79–1.52
2
(br m, 56H, CH of Cy), 1.05–0.90 (br m, 7H, CH of Cy), -0.03 (s,
2
H. C. L. Abbenhuis, A .D. Burrows, H. Kooijman, M. Lutz, M. T.
6H, Si(CH ) ); 13C{1H} NMR (75 MHz, CDCl , 25 °C) δ 139.39
3
2
3
Palmer, R. A. van Santen, and A. L. Spek, Chem. Commun., 1998,
(SiCH=CH ), 131.32 (SiCH=CH ), 112.72, 112.10 (C H ), 27.95,
2 2 5 5
2
627.
27.80, 27.69, 27.58, 27.51, 27.47, 27.34, 27.21, 27.10, 27.06, 27.01,
26.90 (CH ), 24.83, 23.57, 23.55, 22.70, 22.67 (1 : 2 : 2 : 1 : 1 for
CH), 0.10 (Si(CH ) ); Si{ H} NMR (76 MHz, CDCl , 0.02 M
Cr(acac) , 25 °C) δ -3.55, -64.16, -65.22, -66.08, -66.16, -67.73 (1 : 2 :
1 : 1 : 1 : 2).
3
2b: To a solution of 1 (3.06 g, 3.5 mmol) and triethylamine (5.0 cm )
2
3
29
1
in THF (50 cm ), chlorodimethylvinylsilane (0.253 g, 2.1 mmol) in
3
2
3
3
THF (30 cm ) was added dropwise, and the mixture was stirred at
3
room temperature for 20 h. After filtration, resulting clear solution
was evaporated at room temperature to give a white solid. This was
extracted with hexane (60 cm ) to give a clear filtrate and white solid.
16 I. E. Buys, T. W. Hambley, D. J. Houlton, T. Maschmeyer, A. F.
3
Masters, and A. K. Smith, J. Mol. Catal., 86, 309 (1994).
From hexane-insoluble solid, 1.4 mmol of unreacted 1 was recovered.
The filtrate was evaporated, and the product was obtained by the
recrystallization by slow diffusion of acetonitrile into a benzene solu-
tion. Yield 70% (based on chlorodimethylvinylsilane). M.p. 162.1–
17 The reaction was quantitative judging from NMR. 5: 1H NMR (300
MHz, C D , 25 °C) δ 6.37 (s, 5H, C H ), 6.15 (s, 5H, C H ), 3.62 (q,
6
6
5
5
5
5
3J = 7.0 Hz, 2H, OCH CH ), 2.11-1.40 (br m, 56H, CH of Cy),
2
3
2
1.28–1.05 (br m, 7H, CH of Cy), 1.20 (t, 3J = 7.0 Hz, 3H, OCH CH ),
2
3
1
3
1
63.0 °C; H NMR (300 MHz, CDCl , 25 °C) δ 6.22 (dd, J = 20.9
0.61 (s, 4H, Si(CH ) Si), 0.20 (s, 6H), 0.18 (s, 6H, both Si(CH ) );
3
2 2 3 2
C{ H} NMR (75 MHz, CDCl , 25 °C) δ 114.43, 113.71 (C H ),
3 5 5
3
2
13
1
Hz, 14.9 Hz, 1H, SiCH=CH ), 5.99 (dd, J = 14.9 Hz, J = 4.0 Hz,
2
3
2
1
H, cis-SiCH=CH ), 5.82 (dd, J = 20.9 Hz, J = 4.0 Hz, 1H, trans-
58.24 (OCH CH ), 28.59, 28.53, 28.43, 28.30, 28.22, 28.11, 28.08,
2 3
27.82, 27.69, 27.54, 27.35 (CH ), 25.58, 24.17, 24.10, 23.29 (1 : 2 : 2
: 2 for CH), 18.94 (OCH CH ), 9.86, 8.15 (Si(CH ) Si), -0.22, -2.48
2
SiCH=CH ), 4.14 (s, 2H, SiOH), 1.77–1.48 (br m, 56H, CH of Cy,
2
2
2
Cy = c-C H ), 1.05–0.88 (br m, 7H, CH of Cy), 0.23 (s, 6H,
5
9
2
3
2 2
1
3
1
Si(CH ) ); C{ H} NMR (75 MHz, CDCl , 25 °C) δ 139.24
(Si(CH3)2).
18 For example, T. J. Marks, Acc. Chem. Res., 25, 57 (1992).
3
2
3
(
SiCH=CH ), 132.67 (SiCH=CH ), 27.52, 27.43, 27.40, 27.36, 27.27,
2
2