Synthesis and molecular structures of zirconium and hafnium complexes bearing dimethylsilandiyl-bis-2,4,6-trimethylindenyl and dimethylsilandiyl-bis- 2-methyl-4,6-diisopropylindenyl ligands

Article abstract of DOI:10.1016/j.jorganchem.2004.10.052

Zirconium and hafnium ansa-complexes containing 2,4,6-trialkyl-substituted indenyl fragments were synthesized and unambiguously characterized. Mixtures of rac- and meso-Me₂Si(2-Me-4,6-R₂C₉H ₃-η⁵)₂MCl₂, where R = Me, i-Pr and M = Zr, Hf, were obtained by a treatment of MCl₄ by dilithium salts of the respective bis(2,4,6-trialkylindenyl)dimethylsilanes in toluene. Alternatively, better yields of the same complexes can be obtained by the reaction between metal tetrachlorides and indenyl-tin derivatives gave the desired ansa-metallocenes. All rac- and meso-complexes of Zr and Hf were isolated in an analytically pure form, and six of these ansa-metallocenes were characterized by X-ray crystal structure analysis.

Full text of DOI:10.1016/j.jorganchem.2004.10.052

Journal of Organometallic Chemistry 690 (2005) 1067–1079
www.elsevier.com/locate/jorganchem
Synthesis and molecular structures of zirconium and
hafnium complexes bearing
dimethylsilandiyl-bis-2,4,6-trimethylindenyl and
dimethylsilandiyl-bis-2-methyl-4,6-diisopropylindenyl ligands
a
a
b
Vyacheslav V. Izmer , Denis A. Sorokin , Lyudmila G. KuzÕmina ,
Andrei V. Churakov , Judith A.K. Howard , Alexander Z. Voskoboynikov
b
c
a,
*
a
Department of Chemistry, Moscow State University, V-234, Moscow 119899, Russian Federation
N. S. Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, 31, Leninskii pr., Moscow 119991, Russian Federation
b
c
Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
Received 19 June 2004; accepted 5 October 2004
Abstract
Zirconium and hafnium ansa-complexes containing 2,4,6-trialkyl-substituted indenyl fragments were synthesized and unambig-
uously characterized. Mixtures of rac- and meso-Me2Si(2-Me-4,6-R2C9H3-g5)2MCl2, where R = Me, i-Pr and M = Zr, Hf, were
obtained by a treatment of MCl4 by dilithium salts of the respective bis(2,4,6-trialkylindenyl)dimethylsilanes in toluene. Alterna-
tively, better yields of the same complexes can be obtained by the reaction between metal tetrachlorides and indenyl-tin derivatives
gave the desired ansa-metallocenes. All rac- and meso-complexes of Zr and Hf were isolated in an analytically pure form, and six of
these ansa-metallocenes were characterized by X-ray crystal structure analysis.
ꢀ 2004 Elsevier B.V. All rights reserved.
Keywords: Zirconium; Hafnium; Metallocenes
1. Introduction
of substituents in the indenyl fragment. For instance,
the complexes with 4-substituted (preferably aryl) inde-
nyl ligands were found to have outstanding catalytic
properties in the propene polymerization [2]. Ansa-
metallocenes with 4,7-disubstituted indenyl ligands
have been recently described [2–4]. Complexes with
benzoannelated indenyl residue were prepared as well
[2–8]. Meanwile, synthesis of the compounds with
4,6-disubstituted indenyl fragments has not been
described so far. In this paper we report on convenient
methods for the preparation of such 4,6-disubstituted
indenes, the respective dimethylsilandiyl bridged
ligands, and their ansa-complexes of zirconium and
hafnium.
Among chiral ansa-metallocenes the silylene-bridged
bis-indenyl complexes with Me in position 2 have been
most intensively studied because of their application
for a-olefin polymerization [1]. Catalytic properties of
these complexes depend strongly on type and position
*
Corresponding author. Tel.: +7 095 939 4764; fax: +7 095 932
8846.
E-mail address: voskoboy@org.chem.msu.ru (A.Z. Voskoboy-
nikov).
0022-328X/$ - see front matter ꢀ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2004.10.052

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V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
2. Results and discussion
trimethyl-(3) and 2-methyl-4,6-diisopropyl-1H-indenes
(4) were 77% and 65%, respectively.
2.1. Synthesis of 2,4,6-trimethyl-, 2,5,7-trimethyl-, 2-
methyl-5,7-diisopropyl-1H-indenes and the respective
Me2Si-bridged ligands
To synthesize the respective bis(trialkylindenyl)dim-
ethylsilanes, the above-mentioned trialkylindenes were
deprotonated with n-BuLi, and, then, treated with 0.5
equiv. of Me2SiCl2 as shown in Scheme 5. Pure rac-5
was isolated in 40% yield by crystallization of crude
product from n-hexane. A mixture of rac- and meso-dia-
stereomers of 6 was obtained in 61% yield. After distill-
ing off the starting indene, 6 was purified by flash
chromatography.
Mixtures of isomeric trialkyl-substituted indenes were
prepared from the corresponding meta-dialkylbenzenes
as shown in Scheme 1. Whereas the chloromethylation
of m-xylene gave a mixture of 2,4- and 2,6-dimethylben-
zyl chlorides in ratio of 9:2 in 43% yield m-diisopropyl-
benzene formed only 2,4-diisopropylbenzyl chloride in
58% yield. Indanone synthesis from the respective ben-
zyl halides is a well-known procedure [1,2]. In our case,
Lewis acid catalyzed intermolecular cyclization of b-
substituted iso-butyryl chlorides gave 2,4,6-trimethyl-1-
indanone and 4,6-diisopropyl-2-methyl-1-indanone with
86% and 90% yields, respectively. The overall yields of
pure 2,5,7-trimethyl-1H-indene (1) and 5,7-diisopropyl-
2-methyl-1H-indene (2) from m-xylene and m-diisopro-
pylbenzene were 19% and 34%, respectively.
2.2. Synthesis and molecular structures of ansa-
metallocenes
We used two general approaches to the synthesis of
the desired ansa-metallocenes, i.e. (1) the reaction be-
tween di-lithium salts of the ligands and MCl4, where
M = Zr, Hf [1]; (2) the reaction between metal tetrachlo-
rides and indenyl-tin derivatives [16–19].
The bridged ligands 5 and 6 were deprotonated with 2
equiv. of n-BuLi and the resulting dilithium bis-indenyls
were treated with ZrCl4 or HfCl4 in toluene to give ca.
1:1 mixtures of rac- and meso-complexes of zirconium
or hafnium (Scheme 6). Pure diastereomers were iso-
lated by re-crystallization (see Section 3 below).
Alternatively, isomeric indene 3 was prepared from
mesitylene as shown in Scheme 2. In this case, intermo-
lecular cyclization of 2-(3,5-dimethylbenzyl)propionic
acid gave 2,5,7-trimethylindan-1-one in 73% yield [9];
and the overall yield of 3 was 14%.
Another general procedure for the preparation of
indanones is the acid-catalyzed Nazarov-like cyclization
of arylvinylketones (Scheme 3) [10–13]. The respective
arylvinylketones can be prepared by acylation of the
arene by acryloyl chloride or other acrylic acid deriva-
tive. In the presence of excess of AlCl3 electron rich
arenes give the respective indanones via one-pot acyla-
tion-cyclization reaction [4,14,15] as shown in Scheme
4. We used this approach for the synthesis of the desired
trialkylindenes. In this way, the overall yields of 2,4,6-
An alternative transmetallation using softer organo-
tin reagents (Scheme 7) gave the desired complexes,
particularly racemates in better yields. Meso- and rac-
complexes were isolated after re-crystallization from tol-
uene and DME, respectively. It should be noted, that in
the first method using organolithium reagents the yield
of meso-complexes was higher than the yield of the
respective racemates, though in the case of organotin re-
agents the picture was reverse, i.e. racemates were
formed and isolated in higher yield, though the respec-
R
R
R
Cl
Cl
(CH2O)n, HCl
+
R
R
R
R = Me, i-Pr
1. NaCMe(COOEt)2
R
2. KOH, H2O
3. H3O+
4.
R
Cl
SOCl2
COOH
R
R
R
R
R
1. NaBH4
2. P4O10
AlCl3
COOCl
CH2Cl2
R
R
R
1, 2
O
R = Me (1), i-Pr (2)
Scheme 1.

V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
1069
1. NaCMe(COOEt)2
2. KOH, H2O
3. H3O+
SOCl2
NBS
4.
COOH
Br
O
1. NaBH4
2. P4O10
AlCl3
COOH
CH2Cl2
3
Scheme 2.
O
gles are given in Table 1. In all cases, the molecules rep-
resent bent metallosandwiches with nearly planar
indenyl ligands. In general, the geometry of core metal-
locene fragments is close to that previously reported for
other ansa-bis-indenyl complexes of zirconium and haf-
nium with dialkylsilyl bridge [1]. It should be noted that
the pairs of complexes rac-7-rac-8 and meso-7-meso-8
are isostructural.
O
Acid
R
R
Scheme 3.
1. CH2=C(Me)COOCl, AlCl3
2. NaBH4
R
R
3. p-TosOH
3. Experimental
R
R
3, 4
3.1. General procedures
R = Me (3), i-Pr (4)
Scheme 4.
All manipulations with organometallic compounds
have been done either on the high-vacuum line in an
all-glass apparatus equipped with polytetrafluoroethyl-
ene stopcocks or in the atmosphere of thoroughly puri-
fied argon using the standard Shlenk technique. THF
was distilled over LiAlH4. Toluene and hexane were dis-
tilled over Na/K alloy and kept over CaH2. CH2Cl2, as
well CDCl3 and CD2Cl2 were distilled over P4O10 and
kept over 3A molecular sieves. 1H and 13C NMR spectra
were recorded with a Bruker AM 360 spectrometer.
tive meso-complexes were obtained in moderate yield
only. This phenomenon may be associated with sterical
hindrance of the starting materials used. Actually, softer
organotin reagents should give better yields of more
thermodynamically stable products (presumably, race-
mates [1]), though analogous reactions with organoli-
thium compounds would result in higher yield of
kinetically controlled products, i.e. probably organome-
tallic olygomers and meso-complexes bearing bulky
2,4,6-trisubstituted indenyls.
3.2. Mixture of 2,4- and 2,6-dimethylbenzylchlorides
The structures of complexes rac-7, meso-7, rac-8,
meso-8, meso-9, and rac-10 were determined by X-ray
analysis (see Figs. 1–6). Selected bond lengths and an-
A mixture of 200 ml of 12 M HCl, 200 ml (174 g, 1.64
mol) of m-xylene, 88 g of ZnCl2, and 33 g (1.10 mol)
R
R
1. n-BuLi
R
2. Me2SiCl2
Si
Me2
R
R
R
5, 6
R = Me (5), i-Pr (6)
Scheme 5.

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V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
R
R
R
R
R
R
1. n-BuLi
2. MCl4
R
Si
Me2
Me2Si MCl2
Me2Si MCl2
+
R
R
R
R
meso-7: 16%
meso-8: 16%
meso-9: 21%
meso-10: 20%
R
M = Zr, R = Me
M = Hf, R = Me
M = Zr, R = i-Pr
M = Hf, R = i-Pr
rac-7: 11%
rac-8: 12%
rac-9: 15%
rac-10: 14%
Scheme 6.
R
R
R
1. n-BuLi
2. Et3SnCl
3. MCl4
R
R
R
Si
Me2
Me2Si MCl2
Me2Si MCl2
+
R
R
R
R
R
R
M = Zr, R = Me
M = Hf, R = Me
M = Zr, R = i-Pr
M = Hf, R = i-Pr
rac-7: 25%
rac-8: 27%
rac-9: 31%
rac-10: 32%
meso-7: 17%
meso-8: 15%
meso-9: 20%
meso-10: 23%
Scheme 7.
Fig. 1. Molecular structure of complex rac-7. Hydrogen atoms are
omitted for clarity.
Fig. 2. Molecular structure of complex meso-7. Hydrogen atoms are
omitted for clarity.
paraform was treated with HCl gas (prepared from 300
ml of 12 M HCl, 40 g of NaCl, and 300 ml of 98% of
H2SO4) for 3.5 h at room temperature. Then, organic
layer was separated and dried over K2CO3. Fractional
distillation gave colorless product, b.p. 111 ꢁC/18
mm Hg. Yield: 109 g (43%) of a mixture of 2,4- and

V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
1071
Fig. 3. Molecular structure of complex rac-8. Hydrogen atoms are
omitted for clarity.
Fig. 5. Molecular structure of complex meso-9. Hydrogen atoms are
omitted for clarity.
Fig. 4. Molecular structure of complex meso-8. Hydrogen atoms are
omitted for clarity.
2,6-dimethylbenzylchlorides in ratio ca. 9:2. Anal. Calc.
for C9H11Cl: C, 69.90; H, 7.17. Found: C, 69.98; H,
7.14%. 1H NMR(CDCl3): 2,4-dimethylbenzylchloride,
d 7.1–7.4 (m, 3H, C6H3), 4.46 (s, 2H, CH2), 2.30 (s,
3H, Me), 2.24 (s, 3H, Me); 2,6-dimethylbenzylchloride,
d 7.1–7.4 (m, 3H, C6H3), 4.55 (s, 2H, CH2), 2.34 (s,
6H, 2,6-Me2).
3.3. Mixture of 2-(2,4-dimethylbenzyl)- and 2-(2,6-
dimethyl-benzyl)propionic acids
Fig. 6. Molecular structure of complex rac-10. Hydrogen atoms are
omitted for clarity
Sodium metal (15.6 g, 0.68 mol) was dissolved in 550
ml of dry ethanol. To the resulted solution 113 g (0.65
mol) of diethylmethylmalonate was added dropwise
for 10 min; then, 105 g (0.68 mol) of the above-described
mixture of 2,4- and 2.6-dimethylbenzyl chlorides was
added by vigorous stirring at such a rate that the reac-
tion mixture was maintained at gentle reflux. Addition-
ally, this mixture was refluxed for 5 h and cooled to
room temperature. A solution of 135 g (2.41 mol) of

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V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
Table 1
˚
Selected bond lengths (A) and angles (ꢁ) for compounds rac-7, meso-7, rac-8, meso-8, meso-9, and rac-10
Complex
M
rac-7
Zra
meso-7
Zr
rac-8
Hfa
meso-8
Hf
meso-9
Zr
rac-10
Hf
M–Cl(1)
M–Cl(2)
M–C(1)
M–C(10)
M–C(2)
M–C(20)
M–C(3)
M–C(30)
M–C(4)
M–C(40)
M–C(9)
M–C(90)
M–CRb
2.420(3)
2.46(1)
2.50(1)
2.56(1)
2.63(1)
2.569(9)
2.231
2.440(1)
2.395(2)
2.375(3)
2.435(1)
2.3983(8)
2.410(1)
2.459(2)
2.481(2)
2.514(2)
2.508(2)
2.580(2)
2.570(2)
2.631(2)
2.646(2)
2.535(2)
2.570(2)
2.235
2.411(3)
2.434(7)
2.479(7)
2.510(7)
2.496(8)
2.555(8)
2.551(8)
2.628(8)
2.640(8)
2.518(7)
2.548(7)
2.221
2.400(1)
2.469(3)
2.472(3)
2.526(3)
2.502(4)
2.588(3)
2.558(3)
2.645(3)
2.645(3)
2.535(3)
2.567(3)
2.244
2.399(1)
2.445(4)
2.483(4)
2.503(4)
2.520(3)
2.579(4)
2.582(4)
2.637(4)
2.630(4)
2.520(4)
2.530(4)
2.225
2.453(5)
2.477(6)
2.536(7)
2.632(6)
2.550(6)
2.218
b
M–CR0
2.248
2.237
2.241
2.239
Si(1)–C(1)
Si(1)–C(10)
Si(1)–C(13)
Si(1)–C(130)
Cl–M–Cl
1.87(1)
1.85(1)
1.877(2)
1.883(2)
1.862(3)
1.870(3)
97.76(5)
128.1
1.874(6)
1.870(7)
1.867(8)
1.888(8)
1.863(8)
1.878(9)
97.1(1)
1.878(3)
1.881(3)
1.863(4)
1.867(4)
98.41(3)
128.1
1.876(4)
1.886(4)
1.858(4)
1.860(4)
99.12(4)
129.2
98.0(2)
128.4
94.9(6)
97.2(1)
129.0
b
CR–M–CR0
128.4
95.4(3)
105.4(4)
C(1)–Si(1)–C(10)
C(13)–Si(1)–C(130)
95.29(9)
105.2(2)
94.6(3)
105.9(5)
94.7(1)
104.7(2)
95.0(2)
104.7(2)
105(1)
a
Molecule lies on crystallographic two-fold axes.
CR and CR0 denote the centroids of five-membered rings C(1), C(2), C(3), C(4), C(9) and C(10), C(20), C(30), C(40), C(90), respectively.
b
KOH in 350 ml of water was added. This mixture was
refluxed for 4 h to saponificate the ester formed. Ethanol
was distilled off. To the residue 1 liter of water and, then,
12 M HCl (to pH 1) were added. The substituted meth-
ylmalonic acid precipitated at 5 ꢁC was separated,
washed with 3 · 100 ml of cold water and dried. Crude
product was obtained after decarboxilation at 130 ꢁC.
This product was used without further purification.
Yield: 125 g (96%) of a mixture of 2-(2,4-dimethylben-
zyl)- and 2-(2,6-dimethylbenzyl)propionic acids in ratio
ca. 5:1. Anal. Calc. for C12H16O2: C, 74.97; H, 8.39.
h and cooled to room temperature. Then, it was poured
on 1 kg of ice, acidified with 12 M HCl to pH 1, and ex-
tracted with 3 · 200 ml of ether. The combined extracts
were washed with aqueous solution of NaHCO3, dried
over K2CO3, and evaporated to dryness. The crude
product was used without further purification. Yield:
75 g (86%). Anal. Calc. for C12H14O: C, 82.72; H,
1
8.10. Found: C, 82.89; H, 8.23%. H NMR (CDCl3): d
7.38 (s, 1H, 7-H), 7.22 (s, 1H, 5-H), 3.23 (dd, 1H,
J = 17.3 Hz, J = 8.0 Hz, 3-H), 2.68 (m, 1H, 2-H), 2.53
(dd, 1H, J = 17.3 Hz, J = 3.6 Hz, 30-H), 2.35 (s, 3H, 6-
Me), 2.29 (s, 3H, 4-CH3), 1.30 (d, 3H, J = 7.6 Hz, 2-Me).
1
Found: C, 74.78; H, 8.22%. H NMR(CDCl3): d 12.25
(s, COOH), 7.15–6.95 (m, C6H3), 3.25–2.60 (m, CH
and CH2), 2.42 (s, Me), 2.34 (s, Me), 1.4–1.2 (m, Me).
3.5. 2,5,7-Trimethylindene (1)
3.4. 2,4,6-Trimethylindan-1-one
To a solution of 96 g (0.55 mol) of 2,4,6-trimethylin-
dan-1-one in 750 ml of THF/MeOH mixture (2:1) 31.2 g
(0.83 mol) of NaBH4 was added in small portions at 0
ꢁC. This mixture was stirred for 24 h at room tempera-
ture and, then, poured on 700 cm3 of ice, acidified with
12 M HCl to pH 1, and extracted with 3 · 500 ml of
ether. The combined extract was washed with 2 · 200
ml of water, dried over MgSO4, and evaporated to dry-
ness. To the residue 300 ml of benzene and 102 g of
P4O10 was added, and this mixture was refluxed for 1
h. Then, 300 ml of water was added. An organic layer
was separated, washed with water and aqueous solution
of NaHCO3, then, evaporated to dryness. Fractional
distillation gave colorless crystallizable liquid, b.p. 96
ꢁC/1 mm Hg. Yield: 59 g (68%) of white solid of 2,5,7-
The above-described mixture of 2-(2,4-dimethylben-
zyl)- and 2-(2,6-dimethylbenzyl)propionic acids (196 g,
1.02 mol) was stirred with 252 ml (3.50 mol) of thionyl
chloride for 24 h at room temperature. Then, an excess
of thionyl chloride was distilled off. Fractional distilla-
tion of the residue gave colorless liquid, b.p. 125–130
ꢁC/1 mm Hg. Yield: 167 g (78%) of a mixture of 2-
(2,4-dimethylbenzyl)- and 2-(2,6-dimethylbenzyl)propi-
onyl chlorides. To a stirred suspension of 101 g (0.76
mol) of AlCl3 in 1 liter of dry CH2Cl2 a solution of
106 g (0.50 mol) of the isomeric acid chlorides in 200
ml of dry CH2Cl2 was added dropwise for 1.5 h by vig-
orous stirring at 10 ꢁC. This mixture was refluxed for 1.5

V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
1073
trimethylindene. Alternatively, a mixture of 1.07 mol of
the alcohol, 18 g of p-toluenesulfonic acid monohydrate
and 1100 ml of benzene was refluxed for 3 h. Fractional
distillation gave slightly yellow liquid 1, b.p. 87–89 ꢁC/2
mm Hg. Yield: 128 g (81 %). Anal. Calc. for C12H14: C,
C6H3), 6.77 (s, 2H, C6H3), 3.04 (dd, 1H, J = 13.4 Hz,
J = 8.3 Hz, CH H0), 2.76 (m, 1H, CH), 2.57 (dd, 1H,
J = 13.4 Hz, J = 8.2 Hz, CHH0), 2.27 (s, 6H, 3,5-Me2),
1.15 (d, 3H, J = 6.9 Hz, MeCH). 13C{1H} NMR
(CDCl3): d 138.85, 137.72, 127.96, 126.73, 41.17, 39.08,
21.13, 16.32.
1
91.08; H, 8.92. Found: C, 91.20; H, 8.99%. H NMR
(CDCl3): d 6.85 (s, 1H, 4-H), 6.67 (s, 1H, 6-H), 6.35
(s, 1H, 3-H), 3.00 (s, 2H, 1-H), 2.29 (s, 3H, 5-Me),
2.20 (s, 3H, 7-Me), 2.06 (s, 3H, 2-Me).
3.8. 2,5,7-Trimethylindan-1-one
Mixture of 98 g (0.51 mol) of 2-(3,5-dimethylben-
zyl)propionic acid and 126 ml of SOCl2 was stirred for
24 h at room temperature. Thionyl chloride was distilled
off. The residue was dried in vacuo and, then, dissolved
in 200 ml of CH2Cl2. To a suspension of 101 g (0.76
mol) of AlCl3 in 1000 ml of CH2Cl2 the above-men-
tioned solution of 2-(3,5-dimethylbenzyl)propionyl chlo-
ride was added dropwise by vigorous stirring for 1 h 0
ꢁC. This mixture was refluxed for 1.5 h, cooled to ambi-
ent temperature, and, then, poured on 1000 cm3 of iced
water, acidified with 12 M HCl to pH 1. Organic layer
was separated, washed with aqueous NaHCO3, dried
over K2CO3, and evaporated to dryness. Yield: 64.7 g
(73%) of crude 2,5,7-trimethylindan-1-one. This product
was used without further purification. Anal. Calc. for
C12H14O: C, 82.72; H, 8.10. Found: C, 82.90; H,
3.6. Mixture of 3,5-dimethylbenzylbromide and 2,4,6-
trimethylbromobenzene
In a three-necked round-bottom 500 ml flask
equipped with reflux condenser and dropping funnel
with the inlet tube reaching down to the bottom of the
flask, to 250 ml (216 g, 1.8 mol) of mesitylene 102 ml
(316 g, 1.98 mol) of bromine was added dropwise under
exposure to 200 W medium pressure UV lamp for 6 h at
120 ꢁC. The reaction temperature was maintained in the
range of 120–135 ꢁC. The reaction mixture was washed
with 2 · 100 ml of water. Fractional distillation gave
colorless liquid, b.p. 115–125 ꢁC/15 mm Hg. Yield: 144
g (40%) of the mixture of 3,5-dimethylbenzylbromide
(78%) and 2,4,6-trimethylbromobenzene (22%). Anal.
Calc. for C9H11Br: C, 54.30; H, 5.57. Found: C, 54.42;
1
8.25%. H NMR (CDCl3): d 7.02 (br.s, 1H, 6-H), 6.88
1
H, 5.65%. H NMR (CDCl3), 3,5-dimethylbenzylbro-
(br.s, 1H, 4-H), 3.26 (m, 1H, 3-H), 2.61 (m, 2H, 3-H0
and 2-H), 2.58 (s, 3H, 5-Me), 2.36 (s, 3H, 7-Me), 1.27
(d, 3H, J = 7.3 Hz, 2-Me). 13C{1H} NMR (CDCl3): d
209.60, 154.36, 144.70, 138.38, 131.26, 130.10, 124.01,
42.11, 34.16, 21.53, 17.89, 16.23.
mide: d 6.91 (s, 2H, C6H3), 6.83 (s, H, C6H3), 4.30 (s,
2H, CH2), 2.22 (s, 6H, Me). 13C{1H} NMR (CDCl3):
d 137.92, 137.48, 129.61, 126.69, 33.54, 20.88.
3.7. (3,5-Dimethylbenzyl)propionic acid
3.9. 2,4,6-Trimethylindene (3) (Method 1)
Sodium metal (14.8 g, 0.64 mol) was dissolved in 400
ml of dry ethanol. To the resulting solution 107 g (0.62
mol) of diethylmethylmalonate in 100 ml of dry ethanol
was added dropwise within 10 min; then, 129 g (0.65
mol) of 3,5-dimethylbenzylbromide (165 g of the
above-described mixture of 3,5-dimethylbenzylbromide
and 2,4,6-trimethylbromobenzene) was added by vigor-
ous stirring at such a rate, so the reaction mixture main-
tained at gentle reflux. Additionally, this mixture was
refluxed for 5 h and cooled to room temperature. A
solution of 128 g (2.29 mol) of KOH in 350 ml of water
was added. This mixture was refluxed for 4 h to saponif-
icate the ester formed. Viscous oil of 2,4,6-trimethylb-
romobenzene was removed in separatory funnel.
Ethanol was distilled off. To the residue 1 l of water
and, then, 12 M HCl (to pH 1) were added. The substi-
tuted methylmalonic acid precipitated at 5 ꢁC was sepa-
rated, washed with 3 · 100 ml of cold water and dried.
Crude product was obtained after decarboxilation at
130 ꢁC. This product was used without further purifica-
tion. Yield: 81 g (65%). Anal. Calc. for C12H16O2: C,
To a solution of 64.7 g (0.37 mol) of 2,5,7-trimethy-
lindan-1-one in 500 ml of THF/MeOH mixture (2:1)
21 g (0.56 mol) of NaBH4 was added in small portions
at 0 ꢁC. This mixture was stirred for 24 h at room tem-
perature and, then, poured over 500 cm3 of ice, acidified
with 12 M HCl to pH 1, and extracted with 3 · 300 ml of
ether. The combined extract was washed with 2 · 150 ml
of water, dried over MgSO4, and evaporated to dryness.
To the residue 200 ml of benzene and 69 g of P4O10 was
added, and this mixture was refluxed for 1 h. Then, 200
ml of water was added. An organic layer was separated,
washed with water and aqueous solution of NaHCO3,
then, evaporated to dryness. Fractional distillation gave
slightly yellow liquid 3, b.p. 73–77C/1 mm Hg. Yield:
41.4 g (71%). Alternatively, a mixture of 1.07 mol of
the alcohol, 18.3 g of p-toluenesulfonic acid monohy-
drate, and 1200 ml of benzene was refluxed for 3 h.
The product was isolated as described above. Yield:
165 g (71%). Anal. Calc. for C12H14: C, 91.08; H, 8.92.
1
Found: C, 91.01; H, 8.93%. H NMR (CDCl3): d 6.98
(br.s, 1H, 7-H), 6.81 (br.s, 1H, 5-H), 6.49 (br.s, 1H, 3-
H), 3.19 (s, 2H, CH2), 2.32 (s, 3H, 4-Me), 2.30 (s, 3H,
1
74.97; H, 8.39. Found: C, 75.11; H, 8.46%. H NMR
(CDCl3): d 12.12 (br.s, 1H, COOH), 6.83 (s, 1H,

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V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
6-Me), 2.10 (s, 3H, 2-Me). 13C{1H} NMR (CDCl3): d
144.03, 143.43, 141.96, 132.97, 128.32, 127.93, 125.05,
121.64, 42.65, 21.15, 18.31, 16.66.
(142 mmol) of a 2.5 M n-BuLi in hexanes was added
at room temperature. This mixture was refluxed with
vigorous stirring for 3 h, then, cooled to ꢀ40 ꢁC, and
17.3 g (74 mmol) of ZrCl4 was added. The resulted mix-
ture was allowed to warm to room temperature over a
period of 2 h (color changed from yellow to red) and,
then, refluxed for 2 h. The suspension was filtered
(G4), and the precipitate was washed with 100 ml of tol-
uene, 4 · 100 ml of hot DME. Crystallization of the
combined toluene filtrate at ꢀ30 ꢁC gave orange-yellow
crystals of meso-7. Yield: 6.05 g (16%). Then, crystalliza-
tion of the combined DME filtrate at ꢀ30 ꢁC gave yel-
low crystals of rac-7. Yield: 4.11 g (11%). Anal. Calc.
for C26H30Cl2SiZr: C, 58.62; H, 5.68. meso-7: Found:
3.10. 2,4,6-Trimethylindene (3) (Method 2)
To a suspension of 269 g (2.03 mol) of AlCl3 in 1000
ml of CH2Cl2 121 g (1.12 mol) of methacrylchloride in
600 ml of CH2Cl2 was added dropwise at ꢀ70 ꢁC. To
this mixture 122 ml (106 g, 1.00 mol) of m-xylene was
added. This mixture was refluxed for 3 h and stored
for a night at room temperature. Then, this mixture
was poured to 1500 cm3 of ice and acidified with 12 M
HCl to pH 1. Organic layer was separated, washed with
aqueous NaHCO3, dried over K2CO3, and evaporated
to dryness. Following the procedure described for
2,5,7-trimethylindene, crude 2,5,7-trimethylindan-1-
one, 1330 ml of THF/MeOH (2:1), 56.8 g (1.49 mol)
of NaBH4, 1100 ml of benzene, and 16.8 g of p-toluene-
sulfonic acid gave crude title indene. Fractional distilla-
tion gave yellowish 3, b.p. 104 ꢁC/5 mm Hg. Yield: 122 g
(77%). Anal. Calc. for C12H14: C, 91.08; H, 8.92. Found:
C, 91.15; H, 8.99%.
1
C, 58.71; H, 5.76%. meso-7: H NMR (CD2Cl2): d 7.24
(m, 2H, 7,70-H), 6.66 (m, 2H, 5,50-H), 6.51 (m, 2H,
3,30-H), 2.003 (s, 3H, 4-Me), 2.001 (s, 3H, 40-Me), 1.87
(s, 6H, 6,60-Me), 1.802 (s, 3H, 2-Me), 1.799 (s, 3H, 20-
Me), 1.41 (s, 3H, SiMeMe0), 1.19 (s, 3H, SiMeMe0).
rac-7: Found: C, 58.68; H, 5.75%. rac-7: 1H NMR
(CD2Cl2): d 7.21 (m, 2H, 7,70-H), 6.91 (m, 2H, 5,50-H),
6.64 (m, 2H, 3,30-H), 2.24 (s, 6H, 4,40-Me), 2.23 (s,
6H, 6,60-Me), 2.14 (s, 6H, 2,20-Me), 1.24 (s, 6H, SiMe2).
3.11. Bis(2,4,6-trimethylindenyl)dimethylsilane (5)
3.13. Rac- and meso-dimethylsilandiyl-bis(2,4,6-
trimehylindenyl)zirconium dichlorides (rac-7 and meso-
7) (Method 2)
To a solution of 56.4 g (0.36 mol) of 2,4,6-trimethy-
lindene (or 2,5,7-trimethylindene) in 650 ml of THF/tol-
uene (1:12) 143 ml (0.36 mol) of a 2.5 M n-BuLi in
hexane was added by vigorous stirring at room temper-
ature. This mixture was stirred for 1 h at 80 ꢁC, cooled
to 0 ꢁC, and 21.7 ml (23.1 g, 0.18 mol) of Me2SiCl2 was
added dropwise. The reaction mixture was stirred for 1 h
at 80 ꢁC. Then, 100 ml of water was added. An organic
layer was separated and evaporated to dryness. To the
residue 200 ml of cold hexane was added. Product pre-
cipitated from this mixture was filtered (G3), washed
with 2 · 50 ml of hexane, and dried in vacuo over
P4O10. Yield: 26.6 g (40%) of rac-5. Alternatively, the
product was purified by flash chromatography (Silica
Gel 60, hexane/CH2Cl2 = 9/1) and obtained in 34%
yield. Anal. Calc. for C26H32Si: C, 83.81; H, 8.66.
To a solution of 15.3 g (41 mmol) of bis-(2,4,6-trim-
ethylindenyl)dimethylsilane in 140 ml of toluene 49 ml
(82 mmol) of a 1.68 M MeLi in ether was added at room
temperature. This mixture was stirred overnight. Then,
19.7 g (82 mmol) of Et3SnCl (WARNING: Organotin
reagents are very toxic!) was added dropwise, and the
reaction mixture was stirred for 3 h at room temperature
and then evaporated to dryness. The residue was treated
with 170 ml of toluene. The suspension formed was fil-
tered (G4). To the filtrate cooled to ꢀ40 ꢁC, 9.55 g (41
mmol) of ZrCl4 was added, and the resulted mixture
was stirred overnight, then, additionally refluxed for 5
h. The precipitate was filtered off (G4), washed with 50
ml of toluene, then, washed with 3 · 100 ml of hot
DME. Crystallization of the combined toluene filtrate
at ꢀ30 ꢁC gave orange-yellow crystals of meso-7. Yield:
3.71 g (17%). Then, crystallization of the combined
DME filtrate at ꢀ30 ꢁC gave yellow crystals of rac-7.
Yield: 5.46 g (25%). Anal. Calc. for C26H30Cl2SiZr: C,
58.62; H, 5.68. rac-7: Found: C, 58.44; H, 5.54%.
meso-7: Found: C, 58.68; H, 5.73%.
1
Found: C, 83.95; H, 8.72%. H NMR (CDCl3): d 7.21
(s, 2H, 7,70-H), 6.97 (s, 2H, 5,50-H), 6.77 (s, 2H, 3,30-
H), 3.77 (s, 2H, 1,10-H), 2.51 (s, 6H, 4,40-Me), 2.44 (s,
6H, 6,60-Me), 2.30 (s, 6H, 2,20-Me), ꢀ0.18 (s, 6H,
SiMe2). 13C{1H} NMR (CDCl3): d 145.22, 145.00,
141.65, 132.17, 128.52, 127.05, 124.70, 121.51, 47.09,
21.47, 18.64, 17.87, ꢀ5.84.
3.12. Rac- and meso-dimethylsilandiyl-bis(2,4,6-
trimehylindenyl)zirconium dichlorides (rac-7 and meso-
7) (Method 1)
3.14. Rac- and meso-dimethylsilandiyl-bis(2,4,6-
trimehylindenyl)hafnium dichlorides (rac-8 and meso-8)
(Method 1)
To a solution of 26.5 g (71 mmol) of bis-(2,4,6-trim-
ethylindenyl)dimethylsilane in 550 ml of toluene 57 ml
Following the procedure described for rac- and
meso-dimethylsilandiyl-bis(2,4,6-trimehylindenyl)zirco-

V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
1075
nium dichlorides (Method 1), 8.70 g (23.3 mmol) of
3.17. 2-(2,4-Diisopropylbenzyl)propionic acid
bis(2,4,6-trimethylindenyl)dimethylsilane, 18.9 ml (47
mmol) of 2.5 M solution of n-BuLi in hexanes, and
7.47 g (23.3 mmol) of HfCl4 gave yellow-orange crys-
tals of meso-8 and yellow crystals of rac-8. Yields
2.31 g (16%) and 1.73 g (12%) of meso- and rac-com-
plexes, respectively. Anal. Calc. for C26H30Cl2SiHf: C,
50.37; H, 4.88. meso-8: Found: C, 50.48; H, 4.95%.
Sodium metal (16.2 g, 0.71 mol) was dissolved in 400 ml
of dry ethanol. To the resulted solution 117 g (0.69 mol) of
diethylmethylmalonate in 125 ml of ethanol was added
dropwise for 10 min; then, 150 g (0.71 mol) 2,4-diisopro-
pylbenzyl chloride was added by vigorous stirring at such
a rate, so the reaction mixture maintained at gentle reflux.
Additionally, this mixture was refluxed for 5 h and cooled
to room temperature. A solution of 140 g (2.50 mol) of
KOH in 400 ml of water was added. This mixture was re-
fluxed for 4 h to saponificate the ester formed. Ethanol
was distilled off. To the residue 1 liter of water and, then,
12 M HCl (to pH 1) were added. The substituted methyl-
malonic acid precipitated at 5 ꢁC was separated, washed
with 3 · 100 ml of cold water and dried. Crude product
was obtained after decarboxylation at 130 ꢁC. This prod-
uct was used without further purification. Yield: 163 g
(92%). Anal. Calc. for C16H24O2: C, 77.38; H, 9.74.
1
meso-8: H NMR (CD2Cl2): d 7.24 (m, 2H, 7,70-H),
6.60 (m, 2H, 5,50-H), 6.37 (m, 2H, 3,30-H), 2.48 (s,
6H, 4,40-Me), 2.20 (s, 6H, 6,60-Me), 2.16 (s, 6H,
2,20-Me), 1.37 (s, 3H, SiMeMe0), 1.15 (s, 3H,
SiMeMe0). rac-8: Found: C, 50.26; H, 4.80%. rac-8:
1H NMR (C6D6): d 7.29 (m, 2H, 7,70-H), 6.84 (m,
2H, 5,50-H), 6.66 (m, 2H, 3,30-H), 2.27 (s, 6H, 4,40-
Me), 2.23 (s, 6H, 2,20-Me), 2.19 (s, 6H, 6,60-Me),
0.91 (s, 6H, SiMe2).
3.15. Rac- and meso-dimethylsilandiyl-bis(2,4,6-
trimehylindenyl)hafnium dichlorides (rac-8 and meso-8)
(Method 2)
1
Found: C, 77.50; H, 9.85%. H NMR (CDCl3): d 11.91
(br.s, 1H, COOH), 6.87–7.32 (m, 3H, C6H3), 3.35–2.25
(m, 5H, CHMe2, CH(Me)COOH, and CH2), 1.03–1.51
(m, 15H, CHMe2 and CH(Me)COOH).
Following the procedure described for rac- and
meso-dimethylsilandiyl-bis(2,4,6-trimehylindenyl)zirco-
nium dichlorides (Method 2), 24.6 g (66 mmol) of
bis(2,4,6-trimethylindenyl)dimethylsilane, 79 ml (132
mmol) of 1.68 M solution of MeLi in ether, 31.8 g
(132 mmol) of Et3SnCl (WARNING: Organotin re-
agents are very toxic!), and 21.2 g (66 mmol) of HfCl4
gave yellow crystals of rac-8 and yellow-orange crys-
tals of meso-8. Yields 9.52 g (27%) and 5.27 g (15%)
of rac- and meso-complexes, respectively. Anal. Calc.
for C26H30Cl2SiHf: C, 50.37; H, 4.88. rac-8. Found:
C, 50.18; H, 4.75%. meso-8. Found: C, 50.45; H,
4.91%.
3.18. 2-Methyl-4,6-diisopropylindan-1-one
Mixture of 163 g (0.66 mol) of 2-(2,4-diisopropylben-
zyl)propionic acid and 162 ml of SOCl2 was stirred for
24 h at room temperature. Thionyl chloride was distilled
off. The residue was dried in vacuo and, then, dissolved
in 200 ml of CH2Cl2. To a suspension of 130 g (0.98
mol) of AlCl3 in 1800 ml of CH2Cl2 the above-men-
tioned solution of 2-(2,4-diisopropylbenzyl)propionyl
chloride was added dropwise by vigorous stirring for 1
h at 0 ꢁC. This mixture was refluxed for 1.5 h, cooled
to ambient temperature, and, then, poured to 1500
cm3 of iced water, acidified with 12 M HCl to pH 1. Or-
ganic layer was separated, washed with aqueous NaH-
CO3, dried over K2CO3, and evaporated to dryness.
Yield: 137 g (90%) of crude 2-methyl-4,6-triisopropylin-
dan-1-one. This product was used without further puri-
fication. Anal. Calc. for C16H22O: C, 83.43; H, 9.63.
3.16. 2,4-Diisopropylbenzylchloride
A mixture of 400 ml of 12 M HCl, 380 ml (2.35 mol)
of m-diisopropylbenzene, 177 g of ZnCl2, and 65 g of
paraform was treated with HCl gas (prepared from
250 ml of 12 M HCl, 40 g of NaCl, and 250 ml of
98% H2SO4) for 3 h at 80 ꢁC. This reaction mixture
was stored overnight. Then, 60 g of paraform was
added, and the resulted mixture was treated one more
time with HCl gas. Finally, this procedure was repeated
with 40 g of paraform. Organic layer was separated and
dried over K2CO3. Fractional distillation in the presence
of 1 g of NaHCO3 gave colorless oil, b.p. 90–111 ꢁC/1
mm Hg. Yield: 250 g (58%) of the title product. Anal.
Calc. for C13H19Cl: C, 74.09; H, 9.09. Found: C,
74.20; H, 9.14%. 1H NMR(CDCl3): d 7.21–7.01 (m,
3H, C6H3), 4.61 (s, 2H, CH2), 3.28 (sept, 1H, J = 6.9
Hz, CHMe2(1)), 2.88 (sept, 1H, J = 6.6 Hz, CHMe2(2)),
1.27 (d, 6H, J = 6.9 Hz, CHMe2(1)), 1.23 (d, 6H, J = 6.6
Hz, CHMe2(2)).
1
Found: C, 83.58; H, 9.76%. H NMR (CDCl3): d 7.44
(d, 1H, J = 1.44 Hz, 7-H), 7.36 (d, 1H, J = 1.44 Hz, 5-
H), 3.34 (dd, 1H, J = 16.6 Hz, J = 7.6 Hz, 3-H), 3.09
(sept, 1H, J = 6.9 Hz, 6-CHMe2), 2.95 (sept, 1H,
J = 7.2 Hz, 4-CHMe2), 2.67 (m, 1H, 2-H), 2.62 (dd,
1H, J = 16.6 Hz, J = 4.0 Hz, 30-H), 1.31–1.24 (m, 15H,
2-Me and CHMe2). 13C{1H} NMR (CDCl3): d 209.45,
148.77, 148.63, 145.76, 136.24, 129.75, 118.24, 41.89,
33.84, 32.93, 29.56, 23.80, 23.78, 22.66, 16.15.
3.19. 2-Methyl-5,7-diisopropylindene (2)
Following the procedure described for 2,5,7-trime-
thylindene, 137 g (0.60 mol) of 2-methyl-4,6-triisopropy-

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V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
lindan-1-one, 800 ml of THF/MeOH (2:1), 33.7 g (0.90
mol) of NaBH4, 300 ml of benzene, and 110 g of
P4O10 gave the title crude indene. Fractional distillation
gave yellowish liquid 2, b.p. 104–110 ꢁC/1 mm Hg.
Yield: 89 g (70%). Anal. Calc. for C16H22: C, 89.65; H,
J = 6.9 Hz, 4,40-CH Me2), 3.02 (sept, 2H, J = 6.9 Hz,
6.60-CH Me2), 2.28 (s, 6H, 2,20-Me), 1.38–1.25 (m,
24H, 4,40,6,60-CHMe2), 0.20 (6H, SiMe2); meso-, d
7.21 (s, 2H, 7,70-H), 7.09 (s, 2H, 5,50-H), 6.85 (s, 2H,
3,30-H), 3.75 (s, 2H, 1,10-H), 3.34 (sept, 2H, J = 6.9
Hz, 4,40-CHMe2), 3.02 (sept, 2H, J = 6.9 Hz, 6,6-
CHMe2), 2.33 (s, 6H, 2,20-Me), 1.38–1.25 (m, 24H,
4,40,6,60-CHMe2), 0.13 (s, 3H, SiMeMe0), 0.23 (s, 3H,
SiMeMe0).
1
10.35. Found: C, 89.73; H, 10.39%. H NMR (CDCl3):
d 7.11 (s, 1H, 4-H), 6.99 (s, 1H, 6-H), 6.57 (m, 1H, 3-H),
3.34 (s, 2H, 1-H), 3.17 (sept, 1H, J = 7.0 Hz, 5-CHMe2),
3.03 (sept, 1H, J = 6.9 Hz, 7-CHMe2), 2.25 (s, 3H, 2-
Me), 1.42–1.38 (m, 12H, 5,7-CHMe2).
3.22. Rac- and meso-dimethylsilandiyl-bis(2-mehyl-4,6-
diisopropylindenyl)zirconium dichlorides (rac-9 and
meso-9) (Method 1)
3.20. 2-Methyl-4,6-diisopropylindene (4)
To a suspension of 45.3 g (0.339 mol) of AlCl3 in 550
ml of CH2Cl2 29.0 g (0.337 mol) of methacrylchloride in
150 ml of CH2Cl2 was added dropwise at ꢀ70 ꢁC. To
this mixture 50.0 ml (42.8 g, 0.264 mol) of 1,3-diisopro-
pylbenzene in 100 ml of CH2Cl2 was added. This mix-
ture was refluxed for 3 h and stored for a night at
room temperature. Then, this mixture was immersed in
500 cm3 of ice and acidified with 12 M HCl to pH 1. Or-
ganic layer was separated, washed with aqueous NaH-
CO3, dried over K2CO3, and evaporated to dryness.
Following the procedure described for 2,5,7-trimethy-
lindene, crude 2-methyl-5,7-diisopropylindan-1-one,
330 ml of THF/MeOH (2:1), 14.2 g (0.374 mol) of
NaBH4, 260 ml of benzene, and 4.2 g of p-toluenesulf-
onic acid gave the title crude indene. Fractional distilla-
tion gave yellowish liquid 4, b.p. 101–105C/1 mm Hg.
Yield: 36.7 g (65%). Anal. Calc. for C16H22: C, 89.65;
H, 10.35. Found: C, 89.61; H, 10.31%. 1H NMR
(CDCl3): d 7.14 (s, 1H, 7-H), 7.00 (s, 1H, 5-H), 6.64
(s, 1H, 3-H), 3.30 (s, 2H, 1-H), 3.21 (sept, 1H, J = 6.8
Hz, 6-CHMe2), 2.95 (sept, 1H, J = 7.1 Hz, 4-CHMe2),
1.29 (d, 6H, J = 7.1 Hz, 4-CHMe2), 1.33 (d, 6H,
J = 6.8 Hz, 6-CHMe2).
Following the procedure described for rac- and meso-
dimethylsilandiyl-bis(2,4,6-trimehylindenyl)zirconium
dichlorides (Method 1), 15.1 g (31.1 mmol) of bis(2-
methyl-4,6-diisopropyl-indenyl)dimethylsilane, 24.9 ml
(62.3 mmol) of 2.5 M solution of butyllithium in hex-
anes, and 7.59 g (32.6 mmol) of ZrCl4 gave yellow-or-
ange crystals of meso-9 and yellow crystals of rac-9.
Yields 4.21 g (21%) and 3.02 g (15%) of meso- and
rac-complexes,
respectively.
Anal.
Calc.
C34H46Cl2SiZr: C, 63.32; H, 7.19. meso-9: Found: C,
for
1
63.43; H, 7.26%. meso-9: H NMR (CD2Cl2): d 7.17 (s,
2H, 7,70-H), 6.83 (s, 2H, 5,50-H), 6.66 (s, 2H, 3,30-H),
2.97 (sept, 2H, J = 7.0 Hz, 4,40-CHMe2), 2.69 (sept,
2H, J = 6.8 Hz, 6.60-CHMe2), 2.41 (s, 6H, 2,20-Me),
1.38 (s, 3H, SiMeMe0), 1.25 (d, 3H, J = 6.8 Hz, 6-
CHMe2), 1.18 (d, 3H, J = 6.8 Hz, 60-CHMe2), 1.17 (s,
3H, SiMeMe0), 1.14 (d, 3H, J = 7.0 Hz, 4-CHMe2),
1.06 (d, 3H, J = 7.0 Hz, 40-CHMe2). meso-9: 13C{1H}
NMR (CD2Cl2): d 146.90, 145.26, 136.46, 135.37,
130.53, 129.72, 122.44, 121.54, 121.09, 35.96, 33.05,
25.04, 24.60, 24.37, 22.55, 20.10, 4.33, 4.07. rac-9:
1
Found: C, 63.47; H, 7.22%. rac-9: H NMR (CD2Cl2):
d 7.26 (s, 2H, 7,70-H), 7.02 (s, 2H, 5,50-H), 6.74 (s, 2H,
3,30-H), 2.97 (sept, 2H, J = 6.8 Hz, 4,40-CH Me2), 2.81
(sept, 2H, J = 6.8 Hz, 6.60-CH Me2), 2.20 (s, 6H, 2,20-
Me), 1.29 (d, 3H, J = 6.8 Hz, 4-CHMe2), 1.25 (s, 6H,
SiMe2), 1.22 (d, 3H, J = 6.8 Hz, 6-CHMe2), 1.18 (d,
3H, J = 6.8 Hz, 60-CHMe2), 1.17 (d, 3H, J = 6.8 Hz,
40-CHMe2). rac-9: 13C{1H} NMR (CD2Cl2): d 147.90,
145.88, 135.61, 133.20, 129.18, 124.59, 122.21, 121.23,
120.10, 36.16, 33.21, 24.73, 24.72, 24.12, 22.79, 20.00,
4.07.
3.21. Bis(2-methyl-4,6-di-
isopropylindenyl)dimethylsilane (6)
To a solution of 84 g (0.39 mol) of 2-methyl-4,6-diiso-
propylindene in 1200 ml of THF/toluene (1:23) 156 ml
(0.39 mol) of a 2.5 M n-BuLi in hexane was added with
vigorous stirring at room temperature. This mixture was
stirred for 1 h at 80 ꢁC, cooled to 0 ꢁC, and 23.7 ml (25.2
g, 0.195 mol) of Me2SiCl2 was added dropwise. The
reaction mixture was stirred for 1 h at 80 ꢁC. Then,
100 ml of water was added. An organic layer was sepa-
rated and evaporated to dryness. Unreacted 2-methyl-
4,6-diisopropylindene was distilled off at 150 ꢁC/1
mm Hg. Product was purified by flash chromatography
(Silica Gel 60, hexane). Yield: 58 g (61%) of rac-/meso-
mixture of 6. Anal. Calc. for C34H48Si: C, 84.23; H,
3.23. Rac- and meso-dimethylsilandiyl-bis(2-mehyl-4,6-
diisopropylindenyl)zirconium dichlorides (rac-9 and
meso-9) (Method 2)
Following the procedure described for rac- and meso-
dimethylsilandiyl-bis(2,4,6-trimehylindenyl)zirconium
dichlorides (Method 2), 8.57 g (23 mmol) of bis(2-
methyl-4,6-diisopropyl-indenyl)dimethylsilane, 27.5 ml
(46 mmol) of 1.68 M solution of MeLi in ether, 11.1 g
1
9.98. Found: C, 84.39; H, 10.11%. H NMR (CDCl3):
rac-, d 7.34 (s, 2H, 7,70-H), 7.07 (s, 2H, 5,50-H), 6.83
(s, 2H, 3,30-H), 3.78 (s, 2H, 1,10-H), 3.34 (sept, 2H,

Table 2
Crystal data, data collection, structure solution and refinement parameters for rac-7, meso-7, rac-8, meso-8, meso-9, and rac-10
Compound
meso-7
meso-8
rac-7
rac-8
meso-9
rac-10
Empirical formula
Formula weight
Color, habit
C
26H30Cl2Si1Zr1
C26H30Cl2Si1Hf1
619.98
C26H30Cl2Si1Zr1
532.71
C26H30Cl2Si1Hf1
619.98
C34H46Cl2Si1Zr1
644.92
C34H46Cl2Si1Hf1
732.19
532.71
Red block
0.6 · 0.5 · 0.4
Triclinic
Orange block
0.5 · 0.4 · 0.3
Triclinic
Yellow block
0.4 · 0.2 · 0.1
Monoclinic
C2/c
Yellow block
0.3 · 0.3 · 0.1
Monoclinic
C2/c
Yellow block
0.3 · 0.2 · 0.2
Monoclinic
P21/n
Orange block
0.3 · 0.3 · 0.2
Monoclinic
C2/c
Crystal size (mm)
Crystal system
Space group
ꢀ
ꢀ
P1
P1
Unit cell dimensions
˚
a (A)
˚
b (A)
9.106(3)
10.431(4)
14.711(7)
107.16(3)
94.28(3)
110.19(3)
1228.6(9)
2
9.084(8)
10.408(9)
14.69(1)
107.23(9)
94.25(7)
110.08(9)
1222(2)
2
14.674(6)
9.832(6)
16.972(9)
14.654(6)
9.831(6)
16.98(1)
10.104(2)
17.547(5)
18.614(4)
28.4346(9)
9.8833(3)
26.7154(8)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
100.68(5)
100.47(5)
90.97(2)
119.675(1)
3
˚
Volume (A )
2406(2)
4
2046(2)
4
3300(1)
4
6253.1(3)
8
Z
Density (calc.) (g cmꢀ3
)
1.440
1.685
1.471
0.740
1.712
4.620
1.298
0.552
1.491
3.420
Absorption coefficient
(mmꢀ1
F(000)
0.725
4.548
)
548
612
293
1096
293
1224
293
1352
293
2960
Diffractometer
Enraf-Nonius CAD4
Bruker SMART
CCD
Temperature (K)
˚
293
150.0(2)
Radiation (k/A)
Graphite-monochromated Mo Ka (0.71073)
Scan mode
h range (ꢁ)
Index ranges
x
x
x
x
x
x
1.65–27.00
2.20–26.97
ꢀ11 6 h 6 10,
ꢀ2 6 k 6 13,
ꢀ18 6 l 6 18
6037
2.20–24.99
ꢀ10 6 h 6 10,
ꢀ12 6 k 6 12,
ꢀ3 6 l 6 17
5560
2.44–25.00
ꢀ9 6 h 6 18,
ꢀ11 6 k 6 11,
ꢀ21 6 l 6 21
2611
2.44–24.97
ꢀ17 6 h 6 17,
ꢀ11 6 k 6 11,
ꢀ4 6 l 6 20
5464
3.08–25.96
ꢀ11 6 h 6 6,
0 6 k 6 21,
0 6 l 6 22
5170
ꢀ36 6 h 6 36,
ꢀ12 6 k 6 12,
ꢀ34 6 l 6 31
24208
Reflections collected
Independent reflections
Data reduction
5236 [Rint = 0.0163]
XCAD4a
4294 [Rint = 0.0312]
1593 [Rint = 0.0688]
2122 [Rint = 0.0571]
4767 [Rint = 0.1064]
7137 [Rint = 0.0589]
Bruker SAINTb
Empirical
Absorbtion correction
Minimum/maximum
transmission
None
Empirical
None
0.1041/0.5681
0.7360/1.0000
0.4066/0.7277
0.4522/0.6052
Solution method
Direct methods
SHELX-86)c
(
Refinement method
Full-matrix least-squares on F2
(
SHELXL-93)d
4256/0/280
Data/restraints/parameter
Reflections with I > 2r(I)
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
R indices (all data)
5236/0/382
1489/0/141
2103/0/142
4767/0/356
6278/0/356
4836
3929
1372
1956
4259
4621
1.073
1.066
1.133
1.046
1.053
0.992
R1 = 0.0265, wR2 = 0.0719
R1 = 0.0301, wR2 = 0.0739
0.018(1)
R1 = 0.0465, wR2 = 0.1396
R1 = 0.0531, wR2 = 0.1536
0.0001(7)
R1 = 0.1007, wR2 = 0.2896
R1 = 0.1143, wR2 = 0.3202
—
R1 = 0.0365, wR2 = 0.0902
R1 = 0.0414, wR2 = 0.0931
0.0001(1)
R1 = 0.0395, wR2 = 0.1141
R1 = 0.0452, wR2 = 0.1183
0.0053(8)
R1 = 0.0336, wR2 = 0.0713
R1 = 0.0487, wR2 = 0.0835
0.00003(1)
Extinction coefficient
Largest difference
0.501/ꢀ0.606
2.397/ꢀ2.914
1.744/ꢀ1.335
2.692/ꢀ2.163
0.848/ꢀ1.115
0.827/ꢀ0.581
ꢀ3
˚
peak/hole (e A
)
a
K. Harms, XCAD4 – Program for the Lp-Correction of Nonius CAD4 DATA, Marburg, 1997.
SAINT Version 4.050, Bruker AXS, Madison, Wisconsin, USA, 1995.
b
c
G.M. Sheldrick, Acta Crystallogr. Sect. A A46 (1990) 467.
d
G.M. Sheldrick, SHELXL-93 – Program for the Refinement of Crystal Structures, University of Go¨ttingen, Germany, 1993.

1078
V.V. Izmer et al. / Journal of Organometallic Chemistry 690 (2005) 1067–1079
(46 mmol) of Et3SnCl (WARNING: Organotin reagents
are very toxic!), and 5.36 g (23 mmol) of ZrCl4 gave
yellow crystals of rac-9 and yellow-orange crystals of
meso-9. Yields 4.60 g (31%) and 2.97 g (20%) of rac-
and meso-complexes, respectively. Anal. Calc. for
C34H46Cl2SiZr: C, 63.32; H, 7.19. rac-9: Found: C,
63.19; H, 7.04%. meso-9: Found: C, 63.45; H, 7.26%.
6.33. rac-10: Found: C, 55.60; H, 6.26%. meso-10:
Found: C, 55.86; H, 6.33%.
4. X-ray diffraction experimental determination
Crystal data, data collection, structure solution and
refinement parameters of rac-7, meso-7, rac-8, meso-
8, meso-9, and rac-10 are listed in Table 2. All non-
hydrogen atoms in all structures were refined in the
anisotropic approximation. In the case of complex
meso-7 hydrogen atoms were found from difference
Fourier synthesis and refined with isotropic thermal
parameters. In all other cases, hydrogen atoms were
placed in calculated positions and refined using a riding
model. CCDC Reference Nos. 203928-203933. See Sup-
plementary Material section for crystallographic data in
CIF format.
3.24. Rac- and meso-dimethylsilandiyl-bis(2-mehyl-4,6-
diisopropylindenyl)hafnium dichlorides (rac-10 and meso-
10) (Method 1)
Following the procedure described for rac- and meso-
dimethylsilandiyl-bis(2,4,6-trimehylindenyl)zirconium
dichlorides (Method 1), 24.7 g (51 mmol) of bis(2-
methyl-4,6-diisopropyl-indenyl)dimethylsilane, 40.8 ml
(102 mmol) of 2.5 M solution of n-butyllithium in hex-
anes, and 16.3 g (51 mmol) of HfCl4 gave yellow crystals
of meso-10 and rac-10. Yields 5.23 g (14%) and 7.47 g
(20%) of meso- and rac-complexes, respectively. Anal.
Calc. for C34H46Cl2SiHf: C, 55.77; H, 6.33. meso-10:
Found: C, 55.87; H, 6.45%. meso-10: 1H NMR
(CD2Cl2): d 7.18 (s, 2H, 7,70-H), 6.80 (s, 2H, 5,50-H),
6.54 (s, 2H, 3,30-H), 2.95 (sept, 2H, J = 6.9 Hz, 4,40-
CHMe2), 2.71 (sept, 2H, J = 6.9 Hz, 6.60-CHMe2),
2.52 (s, 6H, 2,20-Me), 1.36 (s, 3H, SiMeMe0), 1.23 (d,
3H, J = 6.9 Hz, 6-CHMe2), 1.17 (s, 3H, SiMeMe0),
1.16 (d, 3H, J = 6.9 Hz, 60-CHMe2), 1.14 (d, 3H,
J = 6.9 Hz, 4-CHMe2), 1.06 (d, 3H, J = 6.9 Hz, 40-
CHMe2). meso-10: 13C{1H} NMR (CD2Cl2): d 146.44,
144.89, 135.77, 135.05, 134.30, 128.47, 122.29, 121.02,
119.52, 35.85, 32.99, 25.05, 24.67, 24.35, 22.51, 19.97,
4.30, 4.02. rac-10: Found: C, 55.90; H, 6.40%. rac-10:
1H NMR (CD2Cl2): d 7.29 (s, 2H, 7,70-H), 6.99 (s, 2H,
5,50-H), 6.63 (s, 2H, 3,30-H), 2.96 (sept, 2H, J = 6.8
Hz, 4,40-CHMe2), 2.83 (sept, 2H, J = 7.0 Hz, 6.60-
CHMe2), 2.29 (s, 6H, 2,20-Me), 1.28 (d, 3H, J = 6.8
Hz, 4-CHMe2), 1.24 (s, 6H, SiMe2), 1.21 (d, 3H,
J = 7.0 Hz, 6-CHMe2), 1.19 (d, 3H, J = 7.0 Hz, 60-
CHMe2), 1.18 (d, 3H, J = 6.8 Hz, 40-CHMe2).
Acknowledgements
Financial support from the International Science and
Technology Center (Grant. No. 1036/99), The resident
of the Russian Federation (Grant no. MD-
340.2003.03) INTAS (Grant No. 00-00841) and Exxon-
Mobil Chemical Company is gratefully acknowledged.
L.G.K. and A.V.C. thank the Royal Society of Chemis-
try for the RSC Journal Grants for International
Authors. A.V.C. is grateful to the grant of The President
of Russian Federation for young scientists (Grant no.
MK-3697.2004.03). We also thank Prof. I.P. Beletskaya.
Appendix A. Supplementary data
Supplementary data associated with this article can
be found, in the online version, at doi:10.1016/
j.jorganchem.2004.10.052.
3.25. Rac- and meso-dimethylsilandiyl-bis(2-mehyl-4,6-
diisopropylindenyl)hafnium dichlorides (rac-10 and meso-
10) (Method 2)
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