Synthesis and structure of ansa-metallocene complexes (M=ZrCl2, TiCl2, YCl, and LuCl) containing the bis(2-methyl-4,5,6,7-tetrahydroinden-yl)dimethylsilane ligand

Article abstract of DOI:10.1016/S0022-328X(00)00177-7

The three step synthesis of 2-methyl-4,5,6,7-tetrahydro-1H-indene from cyclohexyl methacrylate is described [(a) PPA cyclization; (b) LiAlH₄ reduction; (c) HCl dehydration]. This annelated trisubstituted cyclopentadiene was bridged selectively to form ethylene- or dimethylsilyl-bridged bis(2-methyl-4,5,6,7-tetrahydro-1H-inden-1-yl) ligands. Metal complexes (M=ZrCl₂, TiCl₂, YCl, and LuCl) of the bis(2-methyl-4,5,6,7-tetrahydroinden-1-yl)dimethylsilane ligand were formed as meso/dl stereoisomeric mixtures in ratios from 1:1 to 2:1 dl:meso.

Full text of DOI:10.1016/S0022-328X(00)00177-7

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 604 (2000) 12–19
Synthesis and structure of ansa-metallocene complexes (M=ZrCl2,
TiCl2, YCl, and LuCl) containing the
bis(2-methyl-4,5,6,7-tetrahydroinden-yl)dimethylsilane ligandꢀ
Ronald L. Halterman a,*1, Herbert Schumann b,*2, Frank Du¨bner a,b
a Department of Chemistry and Biochemistry, Uni6ersity of Oklahoma, Room 208, 620 Parrington O6al, Norman, OK 73019, USA
b Institut fu¨r Anorganische und Analytische Chemie der Technischen Uni6ersita¨t Berlin, Straße des 17. Juni 135, D-10623 Berlin, Germany
Received 4 October 1999; received in revised form 1 March 2000
Abstract
The three step synthesis of 2-methyl-4,5,6,7-tetrahydro-1H-indene from cyclohexyl methacrylate is described [(a) PPA
cyclization; (b) LiAlH4 reduction; (c) HCl dehydration]. This annelated trisubstituted cyclopentadiene was bridged selectively to
form ethylene- or dimethylsilyl-bridged bis(2-methyl-4,5,6,7-tetrahydro-1H-inden-1-yl) ligands. Metal complexes (M=ZrCl2,
TiCl2, YCl, and LuCl) of the bis(2-methyl-4,5,6,7-tetrahydroinden-1-yl)dimethylsilane ligand were formed as meso/dl stereoiso-
meric mixtures in ratios from 1:1 to 2:1 dl:meso. © 2000 Published by Elsevier Science S.A. All rights reserved.
Keywords: Tetrahydroindenyl ligand; ansa-Bis(tetrahydroindenyl)metal; Chiral metallocenes; Zirconocene dichloride; Titanocene dichloride;
Bis(tetrahydroindenyl)yttrium chloride; Bis(tetrahydroindenyl)lutetium chloride
1. Introduction
Only a limited number of bridged bis(tetrahydroinde-
nes) have been reported in the literature due to their
generally difficult synthesis. Without the coordinated
metal to protect the five-membered ring, hydrogenation
of indene itself does not occur on the benzene ring, but
rather it occurs at the styrenyl double bond, leaving the
benzene ring intact. A limited number of achiral un-
bridged ligands such as tetrahydroindene [4], isodi-
cyclopentadiene [5] and bicyclooctane-annelated cy-
clopentadienes [6] have been known for some time.
Attempts to bridge annelated cyclopentadienes such as
tetrahydroindenes are complicated, however, by the
nearly equivalent reactivity in the alkylation or silyla-
tion of the 1- and 2-positions in these cyclopentadi-
enes — in contrast with the electronic preference for
alkylating only at the 1-position of indene. Thus, efforts
to form bridged bis(tetrahydroindenes) have focused on
establishing the bridging position before forming the
cyclopentadiene moiety. Recently, we have reported the
application of the Pauson–Khand cyclization for the
preparation of the first bis(tetrahydroindenes) contain-
ing either the ethylene bridge in 3 or the 1,2-phenylene
bridge in 4 [7]. This general method has been nicely
extended to a bridged chiral variation [8]. Herein we
The reactivities and physical properties of ansa-
bis(indenyl)- or ansa-bis(tetrahydroindenyl)zirconium
dichlorides can be readily compared since the hydro-
genation of easily-prepared ansa-bis(indenyl)zirconium
dichlorides gives the corresponding ansa-bis(tetrahy-
droindenyl)zirconium dichlorides [1]. For example, the
dimethylsilyl bridged ansa-bis(2-methylindenyl)zircon-
ium dichloride (1) was converted into the bis(tetrahy-
droindenyl) derivative 2. Complex 2 was found to be
more active and selective for producing high molecular
weight isotactic polypropylene [2]. The ability to effi-
ciently hydrogenate the six-membered ring in indenyl-
metal complexes is, however, not general and has not
been reported for any indenyllanthanide complexes [3].
Since indenyllanthanides tend to have low solubility, we
desired to produce the presumably more soluble ansa-
bis(tetrahydroindenyl)lanthanum chlorides directly
from ‘pre-reduced’ bis(tetrahydroindenyl) ligands.
ꢀ See Ref. [1].
1 *Corresponding author. Tel.: +1-405-3254836; fax: +1-405-
3256111; e-mail: rhalterman@ou.edu
2 *Corresponding author. E-mail: schumann@chem.tu-berlin.de
0022-328X/00/$ - see front matter © 2000 Published by Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00177-7

R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
13
present an efficient method for the synthesis of the
dimethylsilyl bridged bis(2-methyltetrahydroindene) 5
and its application in the formation of ansa-zir-
conocene and titanocene dichloride and yttrium and
lutetium chloride complexes.
tion mixture of enone 8 and LiAlH4 in diethyl ether
could be directly acidified with concentrated HCl and
this solution heated under reflux for 1 h [11] to give
crude 2-methyltetrahydroindene 10 in good yield. If the
2. Results and discussion
reaction time was prolonged or if the product was
stored for several days, the rearranged diene 11 formed
as the predominant species. MM2 calculations showed
diene 11 to be 1.84 Kcal mol−1 more stable than diene
10 [12]. Chromatographic separation of these isomers
was not feasible and the crude mixture was taken on to
the next step. Deprotonation of the mixture of 10 and
11 with n-BuLi in hexane gave 2-methyl-4,5,6,7-tetrahy-
droindenyllithium (6) in 44% yield as an insoluble white
solid after purification by washing with hexane to re-
move any unreacted or isomerized tetrahydroindenes.
2.1. Synthesis of
2-methyl-4,5,6,7-tetrahydroindenyllithium (6)
In order to overcome the normally unselective reac-
tivity of alkylation at the various unsubstituted sites in
tetrahydroindenes, we chose to block the 2-position by
utilizing 2-methyltetrahydroindene 6 for forming the
bridged ligands. The synthesis of 2-methyltetrahydroin-
dene 6 is illustrated in Scheme 1. A modification of
Conia’s procedure [9,10] for the rearrangement and
PPA-promoted Nazarov cyclization of cyclohexyl
methacrylate 7 at 120°C, followed by vacuum distilla-
tion gave isomeric 2-methyltetrahydroindenones 8 in an
improved yield of 30%. Under our conditions, cycliza-
tion to give the more substituted double bond isomer
8a was favored over the trisubstituted double bond
isomer 8b in a ratio of 85:15. The presence of the
methyl doublet in the 1H-NMR spectrum of 8a was
diagnostic for this isomer, while 8b exhibited a vinyl
hydrogen signal at 6.55 ppm. Reduction of the cy-
clopentenone mixture 8 with excess LiAlH4 in diethyl
ether gave the allylic alcohol 9 as the major stereoiso-
mer in 85% yield. Attempts to dehydrate this cyclopen-
tenol with p-TsOH in benzene or methylene chloride
led only to polymeric material. Alternatively, the reac-
2.2. Bridging of 2-methyl-4,5,6,7-tetrahydroindene
With the preparation of 2-methyl-4,5,6,7-tetrahy-
droindenyllithium (6), we had a ligand that we could
selectively bridge at the equivalent 1- or 3-positions.
Since ethylene and silylene groups are particularly com-
mon bridging groups in ansa-metallocenes, we focused
on their incorporation as one- or two-atom bridges [13].
As shown in Scheme 2, treatment of 2-methyl-4,5,6,7-
tetrahydroindenyllithium (6) with dichlorodimethylsi-
lane in THF gave the silyl-bridged bis(tetrahydroin-
dene) 12 in 59% yield as an inconsequential stereoiso-
meric mixture of dl and meso forms. Attempts at carry-
ing out the silyl bridging in diethyl or dimethyl ether
resulted mainly in the formation of a monosilylindene.
Scheme 1.

14
R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
Scheme 2.
Scheme 3.
The incorporation of the ethylene bridge in ethylene
dene) 15 was ultimately isolated in only 14% yield after
chromatographic purification. Given the poor yields in
our attempts to form ethylene-bridged 15, we were not
able to carry this ligand forward to metal complexes.
bis(tetrahydroindene) 15 proved to be much more trou-
blesome due to a competing intramolecular cyclization
to form the spiro-cyclopropane side product 13. Under
typical conditions [14], the lithium salt 6 was treated
with 1,2-dibromoethane to give a mixture of monote-
trahyroindenylethyl bromide 14, spiro-annelated te-
trahydroindene 13 and traces of the desired bridged
ligand 15. The formation of the spiro side product in
the synthesis of bis(indenes) and bis(cyclopentadienes)
is well known and the reported methods for avoiding it
were attempted [14]. The most successful method for
avoiding spiro-annelation has been to alkylate the mag-
nesium salt generated by deprotonating cyclopentadi-
enes by alkylmagnesium halides [14b]. Unfortunately
during the prolonged period in refluxing THF needed
for the deprotonation by Grignard reagents, tetrahy-
droindene 10 isomerized into the thermodynamically
more stable diene isomer 11, which was the major
isolated product of this treatment. The best method for
the preparation of 15 was an ultimately unsatisfactory
compromise involving the use the isolated lithium salt 6
(freed of any isomerized diene) in an alkylation with
1,2-ethylene ditosylate. As expected, less isomerization
to 11 was observed by deprotonating with n-BuLi, but
rather large amounts of the spiro product 13 were
formed. The desired ethylene bridged bis(tetrahydroin-
2.3. Preparation of [bis(2-methyl-4,5,6,7-
tetrahydroindenyl)dimethylsilane]metal complexes
2.3.1. Preparation of [bis(2-methyl-4,5,6,7-tetra-
hydroindenyl)dimethylsilane]zirconium dichloride (2)
The dimethylsilylene bridged bis(2-methyl-4,5,6,7-te-
trahydroindenyl)zirconium dichloride (2) has been pre-
pared previously through the hydrogenation of the
corresponding bis(indenyl)zirconium dichloride com-
1
plex and the H-NMR spectrum, and polymerization
characteristics of this complex were reported [2]. In our
case (Scheme 3), deprotonation of the dl and meso
mixture of silyl-bridged bis(tetrahydroindene) 12 by
n-BuLi in Et2O was followed by treatment of the
resulting yellow suspension of the dilithio salt with
ZrCl4 at room temperature (r.t.). The solvent was re-
moved in vacuo and the residue was taken up in
methylene chloride and filtered. Removal of the solvent
from this filtrate provided zirconocene 2 as a 1:1 mix-
ture of dl and meso forms in 95% yield. The meso
isomer of 2 was more soluble than the dl isomer in
hexane. Washing the initial 0.9 g of the mixture with

R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
15
hexane (3×40 ml) gave 0.28 g of pure dl-2. The
spectroscopic characterization of this complex is dis-
cussed below.
trahydroindenyl)lanthanide chloride complexes of
lutetium and yttrium, as shown in Scheme 4. Deproto-
nation of 12 as above, followed by metalation with
either LuCl3 or YCl3–THF3 in THF solvent led to the
isolation of a dl/meso mixture of the metal complexes
18 (M=Lu, 90% yield, 1:0.6 dl:meso) and 19 (M=Y,
78% yield, 1:0.9 dl:meso) as light yellow THF adducts.
The coordination of the solvent in either the lutetium
or yttrium complexes could potentially give rise to two
meso diastereomers, but the 1H-NMR spectra evidenced
only one, possibly averaged meso structure. Although
the dl isomer in the lutetium case was favored by
almost a 2:1 ratio, the dl isomer could not be isolated
by fractional recrystallization. Complexes of both
metals were characterized as the diastereomeric mix-
tures.
Metalation of the silyl bridged bis(tetrahydroindene)
12 with tetrakis(dimethylamido)zirconium under equili-
brating conditions in toluene, followed by chloro-
trimethylsilane treatment [15] gave a 96% yield of the
zirconocene dichloride 12 but again with a 1:1 ratio of
1
the dl and meso isomers. The H-NMR spectrum of the
intermediate bis(dimethylamido)bis(2-methyl-4,5,6,7-te-
trahydroindenyl)dimethylsilane]zirconium (16) also in-
dicated a 1:1 ratio of dl and meso isomers. The
frequently observed improvement of the dl:meso ratios
through this amido elimination method was not real-
ized in our case.
2.3.2. Preparation of [bis(2-methyl-4,5,6,7-tetra-
hydroindenyl)dimethylsilane]titanium dichloride (17)
The dilithio salt of silyl-bridged bis(tetrahydroindene)
12 was treated with TiCl3 in THF, followed by air
oxidation in chloroform [16] to give the bis(tetrahy-
droindenyl)titanium dichloride 17 as a brown, air stable
solid as a 1:1 mixture of dl and meso isomers in 78%
yield. These isomers were not separated and were char-
acterized as the mixture.
2.4. NMR spectra of the metallocenes
In the case of zirconocene 2 where the meso and dl
isomers could be separated, the assignments of the
1H-NMR signals could be assigned unambiguously due
to the presence of the two diastereotopic silylmethyl
groups lying in the mirror plane of the meso isomer. In
dl-2, the two silylmethyl groups are equivalent and give
rise to only one signal. In the two lanthanide cases 18
and 19, where the dl:meso ratios were not unity, the
major signals (with only one silylmethyl signal) corre-
sponded to the dl isomers. The remaining titanium
2.3.3. Preparation of [bis(2-methyl-4,5,6,7-tetrahydroin-
denyl)dimethylsilane]lanthanide chlorides (18) and 19
The silyl-bridged bis(tetrahydroindene) 12 did prove
to be a suitable starting material for forming bis(te-
Scheme 4.
Table 1
1H-NMR data for the metal complexes
Complex
Metal
Chemical shift (ppm)
CpꢀH
CpꢀCH3
SiꢀCH3
rac
meso
rac
meso
rac
meso
2
17
16
18
19
Zr
Ti
Zr
Lu
Y
6.45
6.71
6.34
6.18
6.29
6.27
6.49
6.26
6.07
6.21
2.11
2.00
2.19
2.45
2.46
2.23
2.16
2.29
2.56
2.57
0.90
0.93
0.72
0.98
1.04
0.82/0.96
0.87/1.00
0.70/0.74
0.96/1.01
1.01/1.05

16
R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
complex 17 and the bis(amido)zirconium complex 16
were assigned by analogy to give the assignments
shown in Table 1. In each case, the CpꢀH signal in the
meso isomers appeared at higher field, while the CpꢀMe
signal for the meso isomers appeared at lower field.
3.3. 1H-2-Methyl-2,3,4,5,6,7-hexahydroindan-1-ol (9)
To a suspension of LiAlH4 (0.80 g, 21.0 mmol; six
equivalents) in Et2O (200 ml) at 0°C, was added drop-
wise a solution of 2-methyl-4,5,6,7-tetrahydroindan-1-
one (3) (2.20 g, 14.6 mmol) in Et2O (20 ml). After 3 h
at r.t., the suspension was cooled to 0°C and saturated
aqueous potassium sodium tartrate (Rochelle’s salt)
was added dropwise until the evolution of gas stopped.
This mixture was stirred for 30 min, then filtered. The
filtrate was concentrated by rotary evaporation to give
2.5. Summary
2-Methyl-4,5,6,7-tetrahydroindene could be bridged
by dimethylsilane and the bridged bis(indene) could be
converted directly into dimethylsilyl-bridged bis(te-
trahydroindenyl)metal chloride complexes of zirco-
nium, titanium, yttrium and lutetium in dl:meso ratios
of 1:0.6–1:1.
1
9 as a yellow liquid (1.86 g, 84% yield). H-NMR (200
MHz, C6D6, l): 1.07 (d, J=6.6 Hz, 3H, 10-H3), 1.45–
2.45 (m, 11H, 2-H, 3-/5-/6-/7-/8-H2), 3.45 (br-s, 1H,
OH), 4.11 (br-s, 1H, 1-H); 13C-NMR (75.42 MHz,
C6D6, l): 19.18 (C10), 22.67, 25.79, 41.56, 41.77 (C2, 3, 5,
6, 7, 8), 86.61 (C1), 135.74 (C9), 137.34 (C4); MS (70 eV
DIP): 152 (47) [M+], (36) [M+−CH3], 135 (90) [M+−
OH], 109 (48), 107 (40), 79 (100) [M+−
CH3ꢀC2H4ꢀH2CO); IR (NaCl, thin layer in cm−1):
3322, 2926, 2836, 1446, 1277, 1032.
3. Experimental
3.1. General
All operations involving air sensitive compounds
were performed in a nitrogen glove box or under argon
using standard Schlenck glassware techniques. See Refs.
[7] and [14b] for a more complete description of general
techniques and instrumentation used.
3.4. 1H-2-Methyl-4,5,6,7-tetrahydroindene (10)
To a suspension of LiAlH4 (7.80 g, 0.20 mol, four
equivalents) in Et2O (700 ml) at 0°C was added drop-
wise a solution of 2-methyl-4,5,6,7-tetrahydroindan-1-
one (3) (30.9 g, 0.20 mol) in Et2O (100 ml). After
heating for 1 h under reflux, water (100 ml) was added
to the cooled suspension, followed by the addition of
enough concentrated HCl to dissolve all of the alu-
minum hydroxide precipitate. The resulting solution
was then heated under reflux for 1 h. After cooling to
r.t., the phases were separated and the organic portion
was washed with water and saturated aqueous
NaHCO3, and dried over MgSO4. The solvent was
removed by rotary evaporation to give indene 10 as a
yellow liquid (26.5 g, 98% yield), which darkens upon
3.2. 1H-2-Methyl-2,3,4,5,6,7-hexahydroindan-1-one
(8a) [9]
In a three neck flask equipped with an overhead
stirrer and reflux condenser, polyphosphoric acid (500
g) was heated to 100°C. Cyclohexyl methacrylate (130
ml, 0.72 mol) was added to give a deep red solution.
After 1 h, the hot solution was poured into ice water
(500 ml) and the mixture was stirred until the polyphos-
phoric acid completely dissolved. To the resulting
brown mixture was added NH4Cl (10.0 g, 0.19 mol)
and after 30 min the solution was extracted with Et2O
(3×100 ml). The combined organic portion was
washed with 10% aqueous NaHCO3 (100 ml) and satu-
rated aqueous NaCl, and dried over MgSO4. The sol-
vent was removed by rotary evaporation and the
viscous black–red residue was distilled under vacuum
(0.01 mbar, 55°C) to give 8a as a yellow oil (33.0 g, 30%
1
standing. H-NMR (300 MHz, C6D6, l): 1.67 (m, 4H,
6-/7-H2), 1.99 (s, 3H, 10-H3), 2.25 (m, 4H, 5-/8-H2),
2.60 (s, 2H, 3-H2), 6.01 (s, 1H, 1-H); 13C-NMR (75.42
MHz, CDCl3, l in ppm): 17.80 (C10), 22.50, 23.10,
24.20, 25.20 (C5, 6, 7, 8), 46.40 (C3), 129.20 (C2), 135.60
(C4), 137.80 (C9), 140.80 (C1); MS (70 eV DIP, 63°C):
135 (100) [MH+], 133 (25) [M+−H], 119 (22) [M+−
CH3], 105 (27) [M+−HꢀC2H4], 79 (26) [C6H+7 ], 77 (30)
[C6H+5 ], IR (NaCl, thin layer in cm−1): 3036, 2928,
2864, 2836, 1446, 1050.
1
yield). H-NMR (400 MHz, C6D6, l): 1.01 (d, J=7.6
Hz, 3H, 10-H3), 1.37 (m, 4H, 6-H2/7-H2),1.67 (dm,
J=17 Hz, 1H, 3-H), 1.88 (m, 2H, 8-H2), 2.01 (m, 2H,
5-H2), 2.06 (qd, J=7.6/3.3 Hz, 1H, 2-H), 2.27 (dm,
J=17 Hz, 1H, 3-H); 13C-NMR (100.57 MHz, C6D6,
l): 16.56 (C10), 20.57, 22.01, 22.49, 28.21, 38.94 (C3, 5, 6,
7, 8), 39.88 (C2), 137.35 (C9), 169.76 (C4), 208.95 (C1),
MS (70 eV DIP): 150 (56) [M+] 135 (100) [M+−CH3],
122 (30), 79 (91) [M+−C2H4ꢀCO], 77 (62); IR (NaCl,
thin layer, cm−1): 2929, 2868, 1699, 1652, 1277, 1252,
1230, 935.
3.5. (2-Methyl-4,5,6,7-tetrahydroindenyl)lithium (6)
To 2-methyl-4,5,6,7-tetrahydroindene (10) (15.9 g,
0.12 mol) in hexanes (180 ml) under argon was added
n-butyllithium (2.5 M in hexane, 0.14 mol; 1.2 equiva-
lents) at r.t. to give a brighter yellow solution, which
slowly produced a white precipitate. After 12 h at r.t.,

R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
17
(300 MHz, CDCl3, l in ppm): 1.25 (m, 4H, 11-/12-H2),
1.70 (m, 7H, 6-/7-H2, 10-H3), 1.88 (sbr, 2H, 8-H2), 2.30
(m, 2H, 5-H2), 6.07 (s, 1H, 1-H), 13C-NMR (75.42
MHz, CDCl3, l in ppm): 11.80 (C11, 12), 12.50 (C10),
21.00, 22.80, 2380, 25.10 (C5, 6, 7, 8), 37.70 (C3), 127.40
(C2), 136.10 (C4), 138.70 (C9), 144.10 (C1); MS (70 eV
DIP, 60°C): 160 (45) [M+], 145 (95) [M+−CH3], 117
the precipitate was filtered under argon, washed with
hexane and dried under vacuum to give lithium salt 6 as
a white powder (7.20 g, 44% yield). The filtrate con-
tained isomerized diene 11.
3.6. 1,2-Ethylenebis(2-methyl-4,5,6,7-tetrahydroinden-
1-yl) (15)
(100)
[M+−CH3ꢀC2H4],
77
(20)
[M+−
C2H4ꢀC2H4ꢀCH3ꢀC]; IR (NaCl, thin layer in cm−1
)
To a yellow suspension of [2-methyl-4,5,6,7-tetrahy-
droindenyl]lithium (6) (0.80 g, 5.70 mmol) in THF (15
ml) at r.t. was added ethylene-1,2-bis(tosylate) (0.85 g,
2.28 mmol). After stirring for 48 h at r.t., the mixture
was hydrolyzed with saturated aqueous NH4Cl (40 ml)
and extracted with petroleum ether (60 ml total). The
combined organic portion was washed with 10%
aqueous NHCO3 and saturated aqueous NaCl, dried
over MgSO4 and concentrated by rotary evaporation.
The yellow residue was purified by column chromatog-
raphy (H2O–deactivated SiO2, pet ether) to give recov-
ered indene 10, spiro-annelated 11 and the desired
bis(indene) 15 as a colorless oil (93 mg, 14% yield).
1H-NMR (300 MHz, CDCl3, l): 1.05 (m, 4H, 11-H2),
1.20–1.80 (m, 12H, 5-/6-/7-/8-H2), 1.90 (m, 6H, 10-H3),
2.00–2.70 (m, 6H, 5-/8-H2, 3-H), 5.60–5.90 (m, 4H,
1-H); 13C-NMR (75.42 MHz, CDCl3, l): 14.59; 15.32
(C10), 21.42, 23.33, 24.09, 24.40, 25.49, 29.12, 53.79,
55.13, 55.32, 55.73, 55.84 (C3, 5, 6, 7, 8, 11), 124.33, 124.48,
128.88 (C2), 137.34, 137.43, 139.16, 139.27, 139.67,
139.80, 139.84, 156.49 (C1, 4, 9); MS (70 eV DIP, 63°C):
294 (10) [M+], 161 (10) [M+−C10H13], 160 (100) [M+
−C10H14], 145 (66) [M+−C10H14ꢀCH3], 135 (39)
[C10H+15], 117 (54) [M+−C10H14ꢀCH3ꢀC2H4], 105 (96)
[C8H+9 ]; IR (NaCl, thin layer in cm−1): 3042, 2849,
2243, 1699, 1661, 1652, 1634, 1446, 1418, 907, 728.
3080, 3044, 3002, 2928, 2854, 2834, 1439, 993, 845.
3.7. Bis(2-methyl-4,5,6,7-tetrahydroinden-1-yl)-
dimethylsilane (12)
To a yellow suspension of [2-methyl-4,5,6,7-tetrahy-
droindenyl]lithium (6) (1.31 g, 9.30 mmol) in THF (15
ml) at r.t. was added dichlorodimethylsilane (0.45 g,
3.50 mmol, 0.75 equivalents). After 24 h at r.t., the
mixture was hydrolyzed with saturated aqueous NH4Cl
(40 ml) and extracted with petroleum ether (60 ml
total). The combined organic portion was washed with
10% aqueous NHCO3 and saturated aqueous NaCl,
dried over MgSO4 and concentrated by rotary evapora-
tion. The yellow residue was purified by column chro-
matography (H2O–deactivated SiO2, pet ether) to give
12 as a colorless oil (0.67 g, 59% yield). No desired
reaction was observed when diethyl ether was used as
the reaction solvent. Anal. Calc. for C22H32Si: C, 81.41;
H, 9.94. Found: C, 78.14; H, 9.79%. 1H-NMR (300
MHz, CDCl3, l in ppm): −0.272, −0.255, −0.245 (s,
6H, 11-/12-H3), 1.55 (m, 4H, 6-/7-H2), 1.78 (m, 4H,
6-/7-H2), 2.07, 2.09 (s, 6H, 10-H3), 2.32 (m, 8H, 5-/8-
H2), 3.19 (s, 2H, 3-H), 6.03 (s, 2H, 1-H), 13C-NMR
(75.42 MHz, CDCl3, l in ppm): −6.19 (C11, 12), 17.36,
17.49 (C10), 23.29, 23.85, 24.58, 27.20, 27.36 (C5, 6, 7, 8),
52.30 (C3), 129.83 (C2), 137.55 (C4), 137.90 (C9), 141.97
(C1); MS (70 eV DIP, 63°C): 324 (22) [M+], 191 (100)
[M+−C10H13], 131 (55) [C10H1+1], 79 (91) [M+−
C2H4ꢀCO], 59 (12) [HSi(CH3)+2 ], IR (NaCl, thin film in
cm−1): 3037, 2926, 2854, 2836, 1631, 1248, 1001, 830.
3.6.1. 1H-1-(2-Bromoethyl)-2-methyl-4,5,6,7-
tetrahydroindene (14)
When the ethylene-1,2-bis(tosylate) in the preceding
experiment was replaced by 1,2-dibromoethane, the
1
monoalkylated product 14 was also obtained. H-NMR
(300 MHz, CDCl3, l in ppm): 1.68 (m, 4H, 6-/7-H2),
1.94 (s, 3H, 10-H3), 2.20 (sbr, 4H, 5-/8-H2), 2.25 (m, 2H,
3.8. [ansa-Dimethylsiladiyl-bis(2-methyl-4,5,6,7-
tetrahydroinden-1-yl)]zirconium dichloride (2) [2]
3
11-H2), 2.80 (sbr, 1H, 3-H), 3.05 (t, J(1H,1H)=8.0 Hz,
2H, 12-H2), 5.90 (s, 1H, 1-H); MS (70 eV DIP, 36°C):
240/242 (5/6) [M+], 161 (10) [M+−Br], 146 (100)
[M+−BrꢀCH3] 133 (91) [M+−BrꢀC2H4], 117 (22)
To bis[2-methyl-4,5,6,7-tetrahydroindenyl]dimethyl-
silane (12) (0.66 g, 2.00 mmol) in diethyl ether (10 ml)
was added n-butyllithium (2.5 M in hexane, 4.90 mmol,
1.2 equivalents) at 0°C. The mixture was then
stirred for 24 h at r.t. to give a yellow, oily precipitate.
Solid ZrCl4 (0.76 g, 3.20 mmol, 1.6 equivalents)
was added at r.t. to give a yellow suspension. After
24 h at r.t., the volatiles were removed under high
vacuum and CH2Cl2 (20 ml) was added. The resulting
[M+−HBrꢀC2H4ꢀCH3],
105
(78)
[M+−
BrꢀC2H4ꢀC2H4], IR (NaCl, thin layer in cm−1): 2932,
2858, 1699, 1652, 1446, 1352, 1087, 839, 648.
3.6.2. 1H-1,1-Ethano-2-methyl-4,5,6,7-tetrahydroindene
(13)
In both of the preceding experiments, a substantial
1
amount of spiro compound 13 was isolated. H-NMR
suspension was filtered through a glass frit to

18
R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
remove LiCl and concentration of the filtrate gave
zirconocene dichloride 2 as a yellow–brown solid (0.92
g, 95% yield). The dl:meso diastereomeric ratio was
methylene chloride (20 ml). Filtration of the solid LiCl
and concentration of the filtrate gave 2 (0.36 g, 96%
yield) as a yellow powder. The spectroscopic character-
istics matched those reported above.
1
determined by H-NMR spectroscopy to be 1:1. Re-
peated extraction of the solid with hexane could be
used to remove the more soluble meso isomer. Stirring
the crude reaction product with hexane (40 ml), decant-
ing the hexane and repeating twice more gave a yellow
residue of dl-2 (0.28 g, 29%). Recrystallization from
dichloromethane and hexane gave nearly colorless crys-
3.10. [ansa-Dimethylsiladiyl-bis(2-methyl-
4,5,6,7-tetrahydroinden-1-yl)]titanium dichloride (17)
To a solution of bis[2-methyl-4,5,6,7-tetrahydroin-
denyl]dimethylsilane (12) (0.25 g,0.77 mmol) in diethyl
ether (8 ml) at 0°C was added a solution of n-butyl-
lithium (2.5 M in hexane, 1.84 mmol, 1.2 equivalents).
The mixture was then stirred at r.t. for 24 h to give a
yellow oily precipitate. The solvent was removed under
vacuum and the residue was taken up in THF (10 ml).
After cooling this solution to −78°C, TiCl3 (0.19 g,
1.23 mmol, 1.6 equivalents) was added and the resulting
mixture was stirred at r.t. for 12 h to give a dark purple
solution, which when heated under reflux for 4 h turned
black–green. The solvent was removed under vacuum
and the residue taken up at 0°C in chloroform (8 ml).
Air was bubbled through the solution for 4 h and the
solution was then stirred with 2 N HCl (5 ml) for 10
min. The phases were separated and the aqueous phase
extracted with dichloromethane (total of 40 ml). The
combined organic portion was washed with 1 N HCl
and water, dried over magnesium sulfate and concen-
trated by rotary evaporation to give 17 as a waxy solid
(0.26 g, 78% yield). Washing with hexane gave an
air-stable brown solid in a dl:meso ratio of 1:1. M.p.
216°C. 1H-NMR (200 MHz, CDCl3); l 6.71 (s, 2H, H-3
rac), 6.49 (s, 2H, H-3 meso), 2.30–3.45 (m, 16H, H-4,
H-7 rac+meso), 2.16 (s, 6H, ꢁCCH3 meso), 2.00 (s,
6H, ꢁCCH3 rac), 1.30–1.95 (m, 16H, H-5, H-6 rac+
meso) 1.00 (s, 3H, SiCH3 meso), 0.87 (s, 3H, SiCH3
meso), 0.93 (s, 6H, SiCH3 rac); 13C-NMR (50.28 MHz,
CDCl3): l 147.1, 145.8, 137.2, 135.9, 135.2, 133.7,
132.1, 131.8, 96.1, 95.9, 27.4, 27.0, 25.7, 25.5, 22.7, 22.6,
21.7, 21.6, 19.3, 18.5, 1.86 (SiCH3 meso), 1.51 (SiCH3
meso), 1.66 (SiCH3 rac); IR (KBr pellet) 2939, 2864,
1497, 1455, 1435, 1259, 1036, 816 cm−1; MS (12 eV
DIP) 442 (21), 441 (13), 440 (29, M+), 405 (17), 404
(46, M+−Cl), 368 (100, M+−2Cl); Anal. Calc: C,
59.87; H, 6.85. Found: C, 58.90; H, 7.36%.
1
tals of pure dl-2 (m.p. 212°C). H-NMR (200 MHz,
CDCl3): l 6.45 (s, 2H, H-3), 2.40–3.05 (m, 8H, H-4,
H-7), 2.11 (s, 6H, ꢁCCH3), 1.40–1.95 (m, 8H, H-5,
H-6), 0.90 (s, 6H, SiCH3); 13C-NMR (50.28 MHz,
CDCl3): l 138.9, 129.0, 128.8, 127.7, 97.5, 26.7, 24.4,
22.8, 22.0, 17.3, 2.06; IR (KBr pellet) 2939, 2858, 1259,
1097, 1024, 844 cm−1; MS (12 eV DIP) 484 (11), 482
(10, M+), 448 (7), 324 (2), 192 (2), 134 (100, C10H1+4),
132 (21), 119 (25); Anal. Calc: C, 54.52; H, 6.24.
Found: C, 51.27; H, 6.58%.
A sample enriched in the meso-2 isomer was obtained
1
by concentrating the above hexane fractions. H-NMR
(200 MHz, CDCl3): l 6.27 (s, 2H, H-3), 2.30–3.18 (m,
8H, H-4, H-7), 2.23 (s, 6H, ꢁCCH3), 1.40–1.95 (m, 8H,
H-5, H-6), 0.96 (s, 3H, SiCH3), 0.82 (s, 3H, SiCH3);
13C-NMR (50.28 MHz, CDCl3): l 140.0, 130.4, 128.1,
127.4, 97.5, 26.4, 24.5, 23.0, 22.1, 18.2, 2.12, 1.94.
3.9. [Bis(dimethylamido)][ansa-dimethylsiladiyl-
bis(2-methyl-4,5,6,7-tetrahydroinden-1-yl)]zirconium
(16)
To tetrakis(dimethylamido)zirconium (0.24 g, 0.89
mmol; 1.2 equivalents) in toluene (5 ml) at r.t. was
added a solution of bis[2-methyl-4,5,6,7-tetrahydroin-
denyl]dimethylsilane (12) (0.25 g, 0.77 mmol) in toluene
(15 ml). While stirring at 100°C for 14 h, gas was
evolved and the solution deepened from yellow to
orange. The solvent was removed under vacuum to give
16 as an orange pasty solid. The dl:meso ratio was
1
found to be 1:1. H-NMR (200 MHz, C6D6): l 6.26 (s,
2H, H-3 meso), 6.34 (s, 2H, H-3 rac), 3.18 (br, 6H,
NMe2 meso), 3.07 (br, 6H, NMe2 meso), 3.14 (br, 12H,
NMe2 rac), 2.30–2.95 (m, 16H, H-4, H-7 rac+meso),
2.29 (s, 6H, ꢁCCH3 meso), 2.19 (s, 6H, ꢁCCH3 rac),
1.20–1.95 (m, 16H, H-5, H-6 rac+meso) 0.74 (s, 3H,
SiCH3 meso), 0.70 (s, 3H, SiCH3 meso), 0.72 (s, 6H,
SiCH3 rac); 13C-NMR (50.28 MHz, C6D6): l 134.5,
130.8, 124.2, 122.6, 122.2, 121.9, 119.8, 117.1, 106.9,
105.9, 52.0, 49.7, 48.6, 26.6, 26.4, 25.5, 25.1, 24.7, 24.2,
22.9, 17.1, 16.7, 2.29, 2.21.
The crude reaction product was dissolved in benzene
(5 ml) and chlorotrimethylsilane (0.42 g, 3.85 mmol, 1.5
equivalents) was added to the resulting orange solution.
After 14 h at r.t., the volatiles were removed under
vacuum and the yellow solid residue was taken up in
3.11. [ansa-Dimethylsiladiyl-bis(2-methyl-
4,5,6,7-tetrahydroindenyl)]lutetium chloride (18)
To a solution of 12 (0.40 g, 1.23 mmol) in diethyl
ether (8 ml) was added at 0°C n-butyllithium in hexane
(2.71 mmol). The solution was allowed to warm to r.t.
and it was stirred for 24 h to form a yellow precipitate.
The solvent was removed in vacuo and the yellow solid
was taken up in THF (10 ml). The solution was cooled
to −78°C and lutetium trichloride (1.47 mmol, 0.41 g)
was added. After 30 min, the mixture was allowed to

R.L. Halterman et al. / Journal of Organometallic Chemistry 604 (2000) 12–19
19
Acknowledgements
warm to r.t. and it was stirred for an additional 48 h.
The solvent was removed in vacuo and the residue was
extracted with diethyl ether (20 ml). The voluminous
LiCl precipitate was removed by filtration and the
filtrate evaporated in vacuo to give 18 as a light yellow
solid (0.72 g, 90%) in a diastereomeric rac:meso ratio of
1:0.6. Attempts to isolate a single diastereomer by
recrystallization were unsuccessful. The NMR spectra
indicated the presence of coordinated THF, but the
presence of a C2- and only one meso-symmetrical iso-
mer was indicated. Anal. Calc. for C22H30SiLuCl: C,
49.58; H, 5.67. Found: C, 52.13; H, 6.68%. Calc. with
1.5 equivalents of THF: C, 52.45; H, 6.60%. rac:meso
We thank the Partnershaftsprogramm TU Berlin-
University of Oklahoma, the Alexander von Humboldt
Stiftung (Research Fellowship for R.L.H.), the Okla-
homa Center for the Advancement of Science and
Technology (AR7-11) and the Phillips Petroleum Com-
pany for support of this work.
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1
2:1 by NMR spectra. H-NMR (200 MHz, C6D6): l
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(s, 6H, ꢁCCH3 meso), 2.45 (s, 6H, ꢁCCH3 rac), 1.36
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Following the procedure described for the formation
of the lutetium complex 18 using 12 (0.40 g, 1.23 mmol)
in diethyl ether (8 ml), n-butyllithium in hexane (2.71
mmol) and yttrium trichloride–THF3 (0.61 g, 1.47
mmol) gave 19 (0.43 g, 78%) as a light yellow solid in a
1
diastereomeric rac:meso ratio of 1:0.9. H-NMR (200
MHz, C6D6): l 6.29 (s, 2H, H-3 rac), 6.21 (s, 2H, H-3
meso), 3.66 (br, THF), 2.60–3.29 (m, 16H, H-4, H-7
rac+meso), 2.57 (s, 6H, ꢁCCH3 meso), 2.46 (s, 6H,
ꢁCCH3 rac), 1.47 (br, THF), 1.25–2.35 (m, 16H, H-5,
H-6 rac+meso) 1.05 (s, 3H, SiCH3 meso), 1.01 (s, 3H,
SiCH3 meso), 1.04 (s, 6H, SiCH3 rac).
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.