Tetrabenzo[a,c,g,i]fluorenyllithium and η5-tetrabenzo[a,c,g, i]fluorenyltitanium complexes

Article abstract of DOI:10.1021/om0602613

Tetrabenzo[a,c,g,z]fluorene (Tbf-H, 4) was deprotonated with n-butyllithium, leading to ionic Tbf-LiLⁿ complexes 5 and 6, consisting of well-separated cations (Li(THF)₄ (5), Li(DME) ₃ (6)) and Tbf anions. Subsequent reactions with chlorotitanium alkoxides Cl_xTi(OⁱPr)_4-x: (x = 1, 3) and chlorotitanium phenoxides {ClTi(OR)₃(THF)}₂ (R = C ₆H₅ (12), 4-MeC₆H₄ (13), 4- ^tBuC₆H₄ (14)) give a series of η⁵-tetrabenzo[a,c,g,i]fluorenyltitanium complexes (TbfTiCl ₂(OⁱPr) (11) and TbfTi(OR)₃ [R = ⁱPr (10), C₆H₅ (15), 4-MeCe₆H₄ (16), 4-′BuC₆H₄ (17)]), which were characterized by NMR, MS, and IR measurements and X-ray crystallography. Additionally, the compounds' properties regarding the syndiospecific polymerization of styrene when activated with MAO were explored. The activities increase in the following order [kg sPS/(mol Ti × mol styrene × h]: 11 (1420) < 17 (3400) < 16 (3740) < 10 (6040) < 15 (6720).

Full text of DOI:10.1021/om0602613

3824
Organometallics 2006, 25, 3824-3836
Tetrabenzo[a,c,g,i]fluorenyllithium and
η5-Tetrabenzo[a,c,g,i]fluorenyltitanium Complexes
Kai Schro¨der, Detlev Haase, Wolfgang Saak, Arne Lu¨tzen, and Ru¨diger Beckhaus*
Institute for Pure and Applied Chemistry, Carl Von Ossietzky UniVersity, D-26111 Oldenburg, Germany
Silke Wichmann and Ju¨rgen Schellenberg
DOW Central Germany, Research and DeVelopment Engineering Plastics, D-06258 Schkopau, Germany
ReceiVed March 23, 2006
Tetrabenzo[a,c,g,i]fluorene (Tbf-H, 4) was deprotonated with n-butyllithium, leading to ionic Tbf-
LiLn complexes 5 and 6, consisting of well-separated cations (Li(THF)4 (5), Li(DME)3 (6)) and Tbf
anions. Subsequent reactions with chlorotitanium alkoxides ClxTi(OiPr)4-x (x ) 1, 3) and chlorotitanium
phenoxides {ClTi(OR)3(THF)}2 (R ) C6H5 (12), 4-MeC6H4 (13), 4-tBuC6H4 (14)) give a series of η5-
tetrabenzo[a,c,g,i]fluorenyltitanium complexes (TbfTiCl2(OiPr) (11) and TbfTi(OR)3 [R ) iPr (10), C6H5
(15), 4-MeC6H4 (16), 4-tBuC6H4 (17)]), which were characterized by NMR, MS, and IR measurements
and X-ray crystallography. Additionally, the compounds’ properties regarding the syndiospecific
polymerization of styrene when activated with MAO were explored. The activities increase in the following
order [kg sPS/(mol Ti × mol styrene × h]: 11 (1420) < 17 (3400) < 16 (3740) < 10 (6040) < 15
(6720).
systems, such as indenyl,8 fluorenyl,9 or corannulenes,10 the last
one being understood as a formal part of a C60 molecule.11 By
modification of the steric and electronic requirements the
complex properties can be tuned in an excellent way, e.g., in
order to obtain better solubilities and thermal stabilities or to
avoid subsequent reactions.12 Particularly, the fine-tuning of the
steric and electronic properties of these complexes is of interest
in order to optimize properties in catalytic applications such as
the stereoregular polymerization of olefins,13 hydroamination,
or hydroformylation.14 Particularly, half-sandwich titanium(IV)
complexes are useful in the syndiotactic polymerization of
styrene.15 It was shown that monocyclopentadienyl titanium
derivatives show increasing catalytic activities with increasing
steric size of the spectator ligands. In such a way titanium
complexes with 2-phenylcyclopenta[l]phenanthrene16 (1),
2methylbenz[e]indene17 (2), or 1,2,3,4,5,6,7,8-octahydrofluo-
rene18 (3) are important catalysts for styrene polymerization
(Chart 1).
Introduction
The cyclopentadienide anion and its derivatives are widely
used ligands in coordination and organometallic chemistry. It
has been recognized that the replacement of hydrogen atoms
on the cyclopentadienyl ring by substituents influences the
physical and chemical properties of the corresponding metal
complexes.1 In addition to the well-known permethylated ligand
Cp*, a broad range of other Cp substituents are used to prepare
sterically demanding Cp ligands. On one hand, bulky Cp ligands
become available by pentasubstitution employing isopropyl,2
benzyl,3,4 phenyl,5 and ferrocenyl ligands directly6 or indirectly
attached to the five-membered ring.7 On the other hand, more
bulky Cp ligands become available by using fused aromatic ring
* Corresponding author. Phone: + 49 441 798 3656. Fax: + 49 441
798 3851. E-mail: ruediger.beckhaus@uni-oldenburg.de.
(1) Janiak, C.; Schumann, H. AdV. Organomet. Chem. 1991, 33, 291-
393.
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R.; Dezember, T.; Havlas, Z.; Kaim, W.; Moscherosch, M.; Zanathy, L. J.
Am. Chem. Soc. 1993, 115, 12003-12009.
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Czech. Chem. Commun. 2004, 69, 2036-2044. (b) Schumann, H.; Go¨rlitz,
F. H.; Dietrich, A. Chem. Ber. 1989, 122, 1423-1426. (c) Lorberth, J.;
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10.1021/om0602613 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 07/01/2006

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3825
Chart 1
Scheme 1
Scheme 2
Prompted by these developments, we were interested in
developing a nearly planar Cp ligand system with an increasing
number of annulated benzene rings and subsequently tried to
synthesize a novel type of titanium complexes bearing tetra-
benzo[a,c,g,i]fluorenide (Tbf) as ligand. The corresponding
protonated hydrocarbon 8bH-tetrabenzo[a,c,g,i]fluorene (Tbf-H
4a) is easily available starting from 9-bromophenanthrene in a
classical procedure with slight modifications to the protocol
(Scheme 1).19
The tetrabenzo[a,c,g,i]fluorene moiety has not been widely
used in organometallic chemistry so far. Originally, derivatives
of 4 were developed as protecting groups, which exhibit an
increased affinity for charcoal and thus have been applied in
the purification of peptides, proteins, and oligonucleotides.20
Later on, it was also used as an anchor group for solution phase
supported organic synthesis,19 and there was an attempt to use
it in main group organometallic chemistry, e.g., as a polyaro-
matic tag for organotin compounds.21 Here we wish to report
the synthesis and characterization of tetrabenzo[a,c,g,i]fluoren-
yllithium and η5-tetrabenzo[a,c,g,i]fluorenyltitanium complexes.
Furthermore, the applications of the titanium complexes in the
syndiospecific polymerization of styrene, activated with MAO,
are examined.
Results and Discussion
Synthesis and Characterization of Tetrabenzo[a,c,g,i]-
fluorenyllithium. 8bH-Tetrabenzo[a,c,g,i]fluorene (Tbf-H, 4)19
can be deprotonated with n-butyllithium in THF to give TbfLi-
(THF)4 (5) as blocky yellow crystals when stored at -80 °C
(Scheme 2). The substance is soluble in THF, aromatic solvents,
and cyclohexane and exhibits sensitivity to air and moisture,
but is not pyrophoric, in contrast to common lithium cyclopen-
tadienides. In the case of 5, a low melting point without
decomposition of 81 °C is found.
The crystals obtained are suitable for X-ray structure analysis;
5 crystallizes in space group P1h; the triclinic unit cell contains
four separated ion pairs. As seen in the ORTEP plot (Figure
1), the tetrabenzo[a,c,g,i]fluorenide anion is not planar but
exhibits a slightly helical distortion due to steric repulsion of
the aromatic ring protons.
These results raise the question, whether tetrabenzo[a,c,g,i]-
fluorenyllithium also forms separated ion pairs in the solid state,
when other coordinating solvents, such as dimethoxyethane
(DME), are used. Therefore, tetrabenzo[a,c,g,i]fluorenyllithium
was prepared by deprotonation of Tbf-H by n-butyllithium in
toluene. The white precipitate was filtered and redissolved in
DME (Scheme 2). Cooling the resulting yellow solution to -80
°C yields blocky yellow crystals (mp 98 °C), suitable for X-ray
(17) Xu, G.; Cheng, D. Macromolecules 2000, 33, 2825-2831.
(18) Schellenberg, J. J. Polym. Sci. A: Polym. Chem. 2000, 38, 2428-
2439.
(19) Hay, A. M.; Hobbs-Dewitt, S.; MacDonald, A. A.; Ramage, R.
Synthesis 1999, 1979-1985.
(20) (a) Ramage, R.; Raphy, G. Tetrahedron Lett. 1992, 33, 385-388.
(b) Brown, A. R.; Irving, S. L.; Ramage, R. Tetrahedron Lett. 1993, 34,
7129-7132. (c) Ramage, R.; Wahl, F. O. Tetrahedron Lett. 1993, 34, 7133-
7136. (d) Brown, A. R.; Irving, S. L.; Ramage, R.; Raphy, G. Tetrahedron
1995, 51, 11815-11830.
(21) Stien, D.; Gastaldi, S. J. Org. Chem. 2004, 69, 4464-4470.

3826 Organometallics, Vol. 25, No. 16, 2006
Schro¨der et al.
Figure 1. ORTEP plot of the solid-state molecular structure of 5. Hydrogen atoms are omitted for clarity; thermal ellipsoids are drawn at
the 50% probability level. Selected bond lengths [Å] and angles [deg]: C(1)-C(2) 1.404(3), C(1)-C(5) 1.406(3), C(2)-C(3) 1.431(3),
C(3)-C(4) 1.431(3), C(4)-C(5) 1.425(3), C(17)-C(3)-C(4)-C(29) 30.4(4).
ring) and Li cations are found, exhibiting Ct-Li distances (av)
of 5.9/7.2 and 5.8/7.2 Å. Between this Li-Tbf ensemble,
distances (av c, f) of 5.55 Å are found. The Tbf anions fulfill
a honeycomb-like arrangement, showing Tbf molecules alternat-
ing in a horizontal and in a orthogonal arrangement. The C17
atoms of the Tbf molecules are orientated in an alternative
mannersone molecule ahead, the next reversesforming a point
to face (T-shaped) interaction in 5 (2.618 Å shortest contact
H21 center of C47-C52) and in 6 (2.803 Å shortest contact
H13 center of C59-C64).25
NMR experiments were performed on 6 in order to inspect
if the compound also exists as separated ion pairs in solution,
especially in nonpolar solvents such as C6D6. NOE measure-
ments do not reveal any coupling between the protons of the
DME molecules coordinated to the lithium cation and the
protons of the Tbf anion. Therefore, it is assumed that even in
nonpolar solvents separated ion pairs are formed due to the
strong delocalization of the negative charge on the anions’
aromatic ring system.
The tetrabenzofluorenide complexes 5 and 6 represent rare
examples of η0-coordinated carbanions employing “simple”
Lewis bases, such as THF or DME, instead of crown ethers,
for coordinative saturation of the cation.22,26
Synthesis and Characterization of Tetrabenzo[a,c,g,i]-
fluorenyltitanium Complexes. Standard procedures for the
synthesis of half-sandwich titanocene complexes proved not to
be successful with the tetrabenzo[a,c,g,i]fluorenyl ligand system.
For instance, reacting 5 with TiCl4(THF)2 in different solvents
such as THF, toluene, and n-hexane leads to dimerization of
the ligand, forming bis(17-tetrabenzo[a,c,g,i]fluorene) (7) (Scheme
3), a reaction pathway that is known for fluorenyltitanium
compounds and involves oxidation of the ligand anion and its
subsequent radical coupling while reducing the metal center.27
The low solubility of 7 prohibits NMR measurements, whereas
in the EI mass spectra the molecular peak can be observed (m/z
730.2).
Figure 2. ORTEP plot of the solid-state molecular structure of 6.
Hydrogen atoms are omitted for clarity; thermal ellipsoids are drawn
at the 50% probability level. Selected bond lengths [Å] and angles
[deg]: C(1)-C(2) 1.403(2), C(1)-C(5) 1.397(2), C(2)-C(3)
1.425(2), C(3)-C(4) 1.432(2), C(4)-C(5) 1.437(2), C(17)-C(3)-
C(4)-C(18) 22.2(3).
diffraction. Like 5, TbfLi(DME)3 (6) crystallizes in space group
P1h; the triclinic unit cell contains 0.25 equiv of DME in addition
to four separated ion pairs of 6. Like in the case of 5, also for
6 two symmetry-independent molecules are found in the unit
cell. However, the structural data are identical with respect to
the standard deviation; for that reason only one molecule is
discussed. The Li-O distances are found shorter in the
tetrahedral cation 5 (1.876-1.930 Å, av 1.90 Å) compared to
the octahedral cation 6 (2.096-2.190 Å, av 2.13 Å). These
values are in the expected range of Li-O distances.22,23
The packing diagrams of 5 (Figure 3) and 624 show no
bonding contacts between the lithium cations and tetrabenzo-
fluorenyl anions, respectively. Two types of rhombic arrange-
ments (a, b and d, e) of the anions (center of the five-membered
Bis(17-tetrabenzo[a,c,g,i]fluorene) (7) is poorly soluble in any
organic solvent and proves to be highly temperature resistant
for an aromatic compound, as it decomposes without melting
at 363 °C. The compound crystallizes from dichloromethane in
(22) Li-O distances [Å]: [Li(DIGLYME)2]+ 2.043(5)-2.228(5),22 [Li-
(THF)3]+ 1.893-1.955,23a [Li(THF)4]+ 1.924-1.954,23b [Li(DME)3]+
2.082-2.271.23c Neander, S.; Ko¨rnich, J.; Olbrich, F. J. Organomet. Chem.
2002, 656, 89-96.
(23) (a) Rabe, G. W.; Zhang-Presse, M.; Golen, J. A.; Rheingold, A. L.
Acta Crystallogr. 2003, E59, m255-m256. (b) Nikiforov, G. B.; Roesky,
H. W.; Noltemeyer, M.; Schmidt, H.-G. Polyhedron 2004, 23, 561-566.
(c) Wang, H.; Chan, H.-S.; Okuda, J.; Xie, Z. Organometallics 2005, 24,
3118-3124.
(25) Janiak, C. J. Chem. Soc., Dalton Trans. 2000, 3885-3896.
(26) Chen, H.; Jutzi, P.; Leffers, W.; Olmstead, M. M.; Power, P. P.
Organometallics 1991, 10, 1282-1286.
(27) Knjazhanski, S. Y.; Moreno, G.; Cadenas, G.; Belsky, V. K.;
Bulychev, B. M. Tetrahedron 1999, 55, 1639-1646.
(24) For further details see Supporting Information.

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3827
Figure 3. Packing diagram of 5. Hydrogen atoms are omitted for clarity (values of 6 in brackets). Selected distances [Å]: a (red) 5.902
(6.854), b (black) 7.173 (6.829), c (green) 5.469 (6.276), d (pink) 5.835 (7.081), e (blue) 7.209 (7.217), f (dark yellow) 5.586 (6.167).
Scheme 3
space group P21/n; the monoclinic cell unit contains four
molecules of (Tbf)2 along with 4 equiv of dichloromethane
(Figure 4). An extraordinarily long C-C single bond between
C1-C30 (1.615(2) Å) is found, nearly identical to the corre-
sponding C-C bond in a comparable compound described by
Malaba and Youngs.28 A nearly perfect face-to-face π-π
stacking of the C5/C24 and C31/C41 rings is observed (distance
of the ring centers 3.422 Å).25
Figure 4. ORTEP plot of the solid-state molecular structure of 7.
24
Hydrogen atoms and one molecule of CH2Cl2 are omitted for clarity;
thermal ellipsoids are drawn at the 50% probability level. Selected
bond lengths [Å] and angles [deg]: C(1)-C(30) 1.615(2), C(1)-
C(2) 1.509(2), C(1)-C(5) 1.512(2), C(2)-C(3) 1.366(2), C(3)-
C(4) 1.474(2), C(4)-C(5) 1.370(2), C(17)-C(3)-C(4)-C(29) 19.3.
However, as also alternative reactions of Tbf-SiMe3 and
TiCl4 failed, resulting only in unidentified products,29 we were
forced to choose an alternative synthetic path, employing
titanium alkoxides in order to increase the electron density on
the metal center.30 Thus for fluorenyltitanium complexes an
sufficient thermal stability is observed.31 Reacting a solution
of 5 in toluene with ClTi(OiPr)3 (8) at ambient temperature and
subsequent crystallization from n-hexane (-60 °C) yields yellow
crystals of 10 (Scheme 4), which can be isolated in acceptable
yields (68%). The Tbf complex 10 melts at 135 °C and shows
good solubilities in common organic solvents. Of high diagnostic
1
value is the H NMR shift of H17 in 10 (δ 7.6 ppm) (Figure
6). The other signals are in the expected range; further details
are given later on. The crystals obtained were also suitable for
X-ray diffraction (Figure 5). The orthorhombic crystals con-
tained eight molecules of compound 10 in the unit cell (space
group Pbca). The distance Ti(1)-Ct(1) measures 2.120 Å and
is nearly identical to the Ti-Ct distance in (η5-Flu)(η1-Flu)Ti(Oi-
Pr)2 (Flu: fluorenyl, 2.122 Å),31 but longer than in CpTiCl3
(2.01 Å)32 or (η5-Ind)TiCl3 (2.032 Å).33
(28) Malaba, D.; Tessier, C. A.; Youngs, W. J. Organometallics 1996,
15, 2918-2922.
(29) Schro¨der, K. Ph.D. Thesis, Universita¨t Oldenburg, in progress.
(30) Kucht, A.; Kucht, H.; Barry, S.; Chien, J. C. W.; Rausch, M. D.
Organometallics 1993, 12, 3075-3078.
(31) Knjazhanski, S. Y.; Cadenas, G.; Garcia, M.; Perez, C. M.; Nifant’ev,
I. E.; Kashulin, I. A.; Ivchenko, P. V.; Lyssenko, K. A. Organometallics
2002, 21, 3094-3099.
(32) Engelhardt, L. M.; Papasergio, R. I.; Raston, C. L.; White, A. H.
Organometallics 1984, 3, 18-20.

3828 Organometallics, Vol. 25, No. 16, 2006
Schro¨der et al.
Scheme 4
Scheme 5
Figure 5. ORTEP plot of the solid-state molecular structure of
10. Hydrogen atoms are omitted for clarity; thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths [Å] and
angles [deg]: Ti(1)-Ct(1) 2.120, Ti(1)-O(1) 1.775(8), Ti(1)-O(2)
1.768(8), Ti(1)-O(3) 1.823(2), O(1)-C(1) 1.396(3), O(2)-C(4)
1.394(3), O(3)-C(7) 1.319(9), C(10)-C(11) 1.435(3), C(10)-
C(14) 1.417(4), C(11)-C(12) 1.418(4), C(12)-C(13) 1.409(4),
Ti(1)-O(1)-C(1) 165.0(5), Ti(1)-O(2)-C(4) 169.2(2), Ti(1)-
O(3)-C(7) 137.4(5), C(15)-C(10)-C(11)-C(27) 22.4(4).
Two of the OiPr groups show short Ti-O distances (av 1.77
Å), whereas a larger value of 1.823(2) Å is found for the third
group. This corresponds with short C-O distances (av 1.39 Å)
and large Ti-O-C angles (av 167°) for the first two alkoxide
ligands, indicative of higher Ti-O bond orders. On the other
hand, a shorter C(7)-O(3) bond (1.319(9) Å) as well as a
smaller Ti(1)-O(3)-C(7) angle (137.4(5)°) is found.
Being stable as a solid compound, 10 shows some decom-
position, mainly more in polar solvents than in nonpolar ones
(Scheme 5).
As one subsequent product the hydrocarbon 17H-tetrabenzo-
[a,c,g,i]fluorene (4b) is identified, besides an unknown titanium-
containing species.24 The 17H-isomer 4b is the thermodynami-
cally preferred one, compared to 8bH-tetrabenzo[a,c,g,i]fluorene
(4a) as the kinetic one.21 The former can be easily obtained as
needle-shaped monoclinic crystals, suitable for X-ray diffraction,
directly from solutions of 10. 17H-Tetrabenzo[a,c,g,i]fluorene
(4b) crystallizes in space group P2/c with four molecules per
unit cell (Figure 7).
Figure 6. 1H NMR spectrum (500.13 MHz, 300 K) of 10 in CDCl3 (polar solvent) and C6D6 (nonpolar solvent). The asterisks demark
subsequent products.

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3829
Figure 9. ORTEP plot of the solid-state molecular structure of
13. Hydrogen atoms are omitted for clarity; thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths [Å] and
angles [deg]: Ti(1)-Cl(1) 2.343(4), Ti(1)-O(1) 2.056(3), Ti(1)-
O(2) 1.789(8), Ti(1)-O(3) 1.808(4), Ti(1)-O(4) 2.142(4), O(1)-
C(1) 1.383(4), O(2)-C(8) 1.354(3), O(3)-C(15) 1.351(0), Ti(1)-
O(1)-C(1) 125.94(8), Ti(1)-O(2)-C(8) 164.01(1), Ti(1)-O(3)-
C(15) 164.44(1).
Figure 7. ORTEP plot of the solid-state molecular structure of
17H-tetrabenzo[a,c,g,i]fluorene (4b). All protons are freely refined;
thermal ellipsoids are drawn at the 50% probability level. Selected
bond lengths [Å] and angles [deg]: C(1)-C(2) 1.5022(16), C(2)-
C(3) 1.3718(16), C(3)-C(4) 1.4809(16), C(4)-C(5) 1.3719(15),
C(1)-C(5) 1.4971(16), C(17)-C(3)-C(4)-C(18) 22.3(2).
Scheme 6
The preparation of Tbf-titanium phenoxides involved the
development of a suitable type of chlorotitanium aryloxide as
starting material since most complexes of the general formula
ClTi(OAr)3Xn (Ar ) any phenyl, X ) Lewis base, n ) 0-2)
are often only obtained as highly viscous oils or gums and would
thus be quite inconvenient to handle.34 In comparison to the
corresponding aliphatic alkoxides titanium aryloxides are more
Lewis-acidic due to a σn f π* interaction between the lone
pair of the oxygen atom and an antibonding orbital of the aryl-
ring system.35 They can easily be reacted with Lewis bases to
form adducts.36,37 In our search for a convenient starting material
for the preparation of TbfTi(OAr)3 complexes, TiCl4 or Ti(OEt)4
was refluxed with different phenols (phenol, 4-methylphenol,
and 4-tert-butylphenol) in toluene (Scheme 6). After evaporation
of all volatiles the resulting residues were redissolved in THF
and layered with n-hexane to give red to orange crystalline
compounds {ClTi(OAr)3(THF)}2 (12-14). The nearly air-stable
and crystalline aryloxides 12 (mp 94 °C), 13 (mp 109 °C), and
14 (mp 125 °C) are highly soluble in common solvents with
the exception of n-hexane.
Figure 8. ORTEP plot of the solid-state molecular structure of
11. Hydrogen atoms are omitted for clarity; thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths [Å] and
angles [deg]: Ti(1)-Ct(1) 2.049, Ti(1)-O(1) 1.733(3), Ti(1)-Cl(1)
2.284(9), Ti(1)-Cl(2) 2.285(7), O(1)-C(1) 1.426(3), C(4)-C(5)
1.417(3), C(4)-C(8) 1.446(3), C(5)-C(6) 1.422(3), C(6)-C(7)
1.416(3), C(7)-C(8) 1.423(3), Ti(1)-O(1)-C(1) 173.25(1), C(9)-
C(4)-C(8)-C(32) 21.3(4).
The formation of 17H-tetrabenzo[a,c,g,i]fluorene (4b) also
occurs by deliberately protonating 10, which leads to the
assumption that the decomposition process in polar solvents
might employ an intramolecular proton transfer, e.g., due to
the potential acidity of the OiPr group. Reacting 9 with 5 in
toluene, the Tbf complex 11 can be isolated as red crystals (mp
208 °C). Suitable crystals for X-ray structure determination are
obtained by layering the mother liquor with n-hexane (Figure
8). Being in space group P21/c, the cell unit contains four
molecules. The decrease of electron density on the titanium
center leads to a significantly shortened Ti(1)-Ct(1) distance
of 2.049 Å, as opposed to compound 10, and therefore to a
tighter bond between titanium and the spectator ligand. The
Ti(1)-O(1) distance (1.733(3) Å) is indicative of an expected
dπ-pπ interaction, leading to a large Ti-O-C angle of
173.25(1)°. As opposed to 10, compound 11 is stable in all
solvents.
Suitable crystals of 13 for X-ray diffraction were obtained
from a THF solution layered with n-hexane. Compound 13
crystallized as monoclinic red-orange crystals in space group
P21/c. The phenoxide 13 is characterized by the formation of
two equivalent molecule parts, bridged by phenolate ligands
(Figure 9). Each titanium atom is coordinated in an octahedral
(33) Ready, T. E.; Day, R. O.; Chien, J. C. W.; Rausch, M. D.
Macromolecules 1993, 26, 5822-5823.
(34) Bradley, D.; Mehrotra, R. C.; Rothwell, I. Alkoxo and Aryloxo
DeriVatiVes of Metals; Academic Press: London, 2001; pp 1-687.
(35) Nielson, A. J.; Schwerdtfeger, P.; Waters, J. M. J. Chem. Soc.,
Dalton Trans. 2000, 529-537.
(36) Gupta, R.; Singh, A.; Mehrotra, R. C. Indian J. Chem. 1990, 29A,
596-598.
(37) Malhotra, K. C.; Sharma, N.; Bhatt, S. S.; Chaudhry, S. C.
Polyhedron 1992, 11, 2065-2068.

3830 Organometallics, Vol. 25, No. 16, 2006
Schro¨der et al.
Scheme 7
Scheme 8
fashion; the Ti(1)-O(1) (2.056(3) Å) bond is found to be longer
than Ti(1)-O(2) (1.789(8) Å) and Ti(1)-O(3) (1.808(4) Å).
The Ti(1)-Cl(1) bond (2.343(4) Å) is longer than expected
(2.305 Å),38 whereas the bond length to the coordinated THF
molecule is in the typical range (2.142(4) Å).
dependent NMR experiments were conducted in order to
determine the energetic barrier for interconversion of both
isomers (Figure 12). A sample of compound 16, which was
chosen due to its good solubility and stability, was dissolved in
CDCl3, and measurements were taken within a temperature
range of 300-203 K in the attempt to “freeze in” the flipping
movement of the benzo-fused rings. Unfortunately, a complete
stoppage and thus a 2-fold signal set could not be achieved.
The spectra show only what seems to be a deceleration of the
interconversion movement as the doublet for the H-8/H-9
protonsswhich cause the ligand to twist helically due to their
steric repulsionsis shifted upfield with decreasing temperature.
Reacting the chlorotitanium triphenoxides 12, 13, and 14 with
5 in cyclohexane or toluene at ambient temperature yields
mononuclear tetrabenzo[a,c,g,i]fluorenyltitanium triaryloxides
TbfTi(OAr)3 (Ar ) C6H5 (15), 4-MeC6H4 (16), 4-tBuC6H4 (17)).
These Tbf-titanium aryloxides are obtained as red crystalline
solids (mp 153 °C (15), 154 °C (16), 173 °C (17) showing
acceptable solubilities in common solvents with the exception
of n-hexane. Layering the mother liquors with n-hexane yielded
crystals suitable for X-ray diffraction of compounds 15 and 16
(Figures 10, 11). Any attempts to obtain crystals of compound
17 that would have been suitable for X-ray diffraction have not
been successful so far. Compound 15 crystallizes in the
monoclinic space group P21/n with four molecules per unit cell,
whereas 16 crystallizes in the triclinic space group P1h with two
molecules per unit cell.
The Tbf complexes 15 and 16 are characterized by the
formation of a tetrahedral-coordinated titanium center. The
Ti(1)-Ct distances in 15 (2.069 Å) and 16 (2.067 Å) are shorter
than those in 10 (2.120 Å). Similar to 10, also for 15 two shorter
(av 1.80 Å) and one longer Ti(1)-O(1) bond (1.851(6) Å) are
found. The short distances correlate also as in 10 to the Ti-
O-C angles. For 16 three different Ti-O bond lengths are
found. Short contacts of the aromatic rings (center of C(18)/
C(23) and C(42)/C(47) 3.78 Å) in 15 are indicative again of a
face-to-face π-π stacking.25
Due to the helical shape of the ligand, all η5-tetrabenzo-
[a,c,g,i]fluorenyltitanium complexes exhibit C1-symmetry, giv-
ing two optical isomers, both of which crystallize as a racemate
leading to centrosymmetric space groups (Table 5).
NMR spectroscopy reveals that in solution both isomers
rapidly interconvert, as instead of a 2-fold signal set, which
would be indicative of two isomers, only half the signal set
can be observed at ambient temperature. Thus temperature-
Figure 10. ORTEP plot of the solid-state molecular structure of
15. Hydrogen atoms are omitted for clarity; thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths [Å] and
angles [deg]: Ti(1)-Ct(1) 2.069, Ti(1)-O(1) 1.851(6), Ti(1)-O(2)
1.799(3), Ti(1)-O(3) 1.806(9), O(1)-C(30) 1.358(8), O(2)-C(36)
1.348(7), O(3)-C(42) 1.356(3), C(1)-C(2) 1.402(3), C(1)-C(5)
1.424(4), C(2)-C(3) 1.438(3), C(3)-C(4) 1.452(4), C(4)-C(5)
1.431(3),Ti(1)-O(1)-C(30)142.76(1),Ti(1)-O(2)-C(36)166.11(1),
Ti(1)-O(3)-C(42) 161.52(1), C(17)-C(3)-C(4)-C(18) 11.7(5).
(38) Orpen, A. G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson, D.
G.; Taylor, R. J. Chem. Soc., Dalton Trans. 1989, S1-S83.

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3831
1
Table 1. Selected H (ppm, C6D6, 500.13 MHz, 300 K) NMR
Data of Compounds 5 and 6
5
6
H-1/H-16
H-2/H-15
H-3/H-14
H-4/H-13
H-5/H-12
H-6/H-11
H-7/H-10
H-8/H-9
H-17
8.48
7.53
7.40
8.59
8.60
7.35
7.48
9.30
7.690
8.49
7.55
7.41
8.60
8.62
7.36
7.48
9.28
7.670
Figure 11. ORTEP plot of the solid-state molecular structure of
16. Hydrogen atoms are omitted for clarity; thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths [Å] and
angles [deg]: Ti(1)-Ct(1) 2.067, Ti(1)-O(1) 1.829(9), Ti(1)-O(2)
1.844(5), Ti(1)-O(3) 1.800(0), O(1)-C(30) 1.353(2), O(2)-C(37)
1.359(2), O(3)-C(44) 1.361(2), C(1)-C(2) 1.431(2), C(1)-C(5)
1.418(3), C(2)-C(3) 1.437(3), C(3)-C(4) 1.433(3), C(4)-C(5)
1.417(3),Ti(1)-O(1)-C(30)150.10(1),Ti(1)-O(2)-C(37)141.72(1),
Ti(1)-O(3)-C(44) 160.28(1), C(18)-C(3)-C(19)-C(17) 13.3(4).
for the triaryloxide derivatives all fall in the same range the
above-mentioned proton signals of compound 11 are shifted
downfield about 0.2 ppm. Most interestingly, this shift correlates
with different Ti-Ct bond lengths and twist angles of the
helically shaped ligand found in X-ray crystal structures (Table
3). The torsion angle between the carbon atoms denoted a, b,
c, and d can be taken as indicative of the ligands’ helical
twisting. Interestingly, this torsion angle is almost identical in
17H-Tbf (4b), in the anion of 6, and in the complexes 10 and
When comparing the NMR data of the different η5-tetrabenzo-
[a,c,g,i]fluorenyltitanium complexes (Table 2), one difference
between the compounds measured in CDCl3 is striking: Whereas
the proton signals of H-1/H-16, H-4/H-13, H-5/H-12, and H-17
1
Figure 12. Variable-temperature H NMR spectrum (300.13 MHz, CDCl3) of 16. Only the range relevant for the tetrabenzo[a,c,g,i]-
fluorenyl ligand is shown.

3832 Organometallics, Vol. 25, No. 16, 2006
Schro¨der et al.
1
Table 2. Selected H NMR Data (500.13 MHz, 300 K) of
indicating syndiotactic polymers. Furthermore, on the basis of
the melting points the polystyrenes show a very high degree of
syndiotacticity, comparable to about 100% of the rrrrr-hexad
fraction via 13C NMR, in comparison to, for example, syndio-
tactic polystyrene of a melting point of 257 °C and a rrrrr-hexad
fraction of 89% received with CpTiCl3 as catalyst.39
Compounds 10, 11, and 15-17 (numbering scheme in
accordance with Table 1)
10
11
15
16
17
solvent
C6D6
8.24
7.47
a
8.41
8.43
a
CDCl3
8.39
a
CDCl3
8.14
7.60
7.53
8.38
8.41
7.48
7.56
8.81
7.800
CDCl3
8.16
7.63
7.56
8.43
8.45
7.50
7.59
8.83
7.795
CDCl3
8.14
7.58
7.51
8.33
8.36
7.48
7.54
8.81
7.793
H-1/H-16
H-2/H-15
H-3/H-14
H-4/H-13
H-5/H-12
H-6/H-11
H-7/H-10
H-8/H-9
H-17
a
Conclusions
8.60
8.63
a
7.60
8.85
8.014
The efficient synthesis of 4a allows an effective access to
the organometallic chemistry of the tetrabenzo[a,c,g,i]fluorenyl
moieties. Using the remarkable η0-coordinated lithium salts 5
and 6 monosubstituted titanium(IV) alkoxides and aryloxides
become available. The tetrabenzo[a,c,g,i]fluorenyl moiety is
coordinated as a sterically demanding Cp derivative in a η5-
fashion to the titanium centers. The formal benzannelation of
the fluorenyl system, as present in the Tbf titanium complexes,
leads to large mono-Cp complexes of high thermal stability
compared to η5-fluorenyl titanium derivatives. Due to its helical
twist, the η5-coordinated tetrabenzo[a,c,g,i]fluorenyl ligands
show C1-symmetry in the solid state but seem to interconvert
in solution. Additionally, the titanium complexes were subjected
to polymerization experiments of styrene to some extent.
a
9.14
7.596
a Signals could not be clearly assigned.
11 despite their different electronic situations. In the triaryloxide
complexes 15 and 16 the torsion angle declines from an average
22° (6, 10, 11) to 11.7(5)° (15) and 13.3(4)° (16), respectively.
Comparison of bond lengths in the Tbf moiety reveals that
the C-C distances of the five-membered ring are strongly
influenced by the charge of the molecule. In the Li salts 5 and
6 the C17-C18 and C17-C29 bonds (av 1.40 Å, numbering
in accordance with Table 1) are found to be shorter than in the
neutral compounds 4b and 7 (av 1.50 Å). A similar shortening
is observed for the titanium complexes 10, 11, 15, and 16 (av
1.41 Å). The C24-C29 as well as the C18-C23 bond is
elongated comparing the neutral (av 1.37 Å), ionic, and titanium
derivatives (av 1.43 Å). Also the C23-C24 distances are
influenced, as expected, for the neutral derivatives, 1.40 Å (av),
the lithium salts, 1.43 Å (av), and the titanium complexes, 1.44
Å (av). The other C-C distances are less influenced by
electronic effects. However, an increasing aromatic character
of the annelated rings is found comparing 4b and 7 with the
lithium as well as the titanium complexes. In such a way the
C-C distances C20-C21, C26-C27 (x); C18-C19, C28-C29
(y), and C23-C22, C24-C25 (z) of the central six-membered
rings increase significantly from the neutral to the lithium up
to the titanium Tbf derivatives (x, av: neutral 1.45, Li 1.46, Ti
1.47 Å; y, av: neutral 1.42, Li: 1.44, Ti 1.45 Å; z, av: neutral
1.45, Li 1.45, Ti 1.46 Å).
Styrene Polymerization. To assess the capability of the
complexes as catalysts in polymerization reactions, the coor-
dination polymerization of styrene as a monomer was investi-
gated in the presence of the η5-tetrabenzo[a,c,g,i]fluorenyltita-
nium complexes. Methylalumoxane (MAO) was selected as a
cocatalyst and was used in relatively low concentrations with
regard to the transition metal, corresponding to a molar ratio
MAO/Ti ) 110/1. In addition, triisobutylaluminum (TIBA) was
used as a strong reducing agent for the titanium compound and
was added in a molar ratio of TIBA/Ti ) 25/1. The polymeriza-
tions were initiated at a high molar ratio styrene/Ti ) 700 000/
1 by addition of the catalyst premix solution to the styrene
monomer at 30 °C. The polymerization results (Table 4) indicate
a significant activity of all η5-tetrabenzo[a,c,g,i]fluorenyltitanium
complexes as catalysts in the coordination polymerization of
styrene with MAO as cocatalyst. However, the polymerization
activity of the different complexes varies depending on the kind
of ancillary ligands in addition to the η5-tetrabenzo[a,c,g,i]-
fluorenyl group. The activity increases in the following order:
11 (1420 kg sPS/(mol Ti × mol styrene × h) < 17 (3400) <
16 (3740) < 10 (6040) < 15 (6720). On the other hand, the
stereospecificity of the complexes as catalysts in the coordination
polymerization of styrene can be determined by investigation
of the melting points of the polystyrenes received by DSC (Table
4). All polymer samples obtained exhibited high melting points,
Experimental Section
Reagents and General Techniques. All operations were per-
formed in a nitrogen atmosphere with rigorous exclusion of oxygen
and moisture using glovebox or Schlenk techniques. All chemicals
used were reagent grade or higher and purified according to standard
protocols. Nonchlorinated solvents were distilled over Na/K alloy
and benzophenone under nitrogen atmosphere. Dichloromethane
was distilled over CaH2 under nitrogen atmosphere. Trichlorotita-
nium isopropoxide (9) was prepared according to literature.40 1H
and 13C NMR spectra were recorded on a Bruker AVANCE 500
(1H, 500.13 MHz; 13C, 125.75 MHz) spectrometer. Variable-
temperature NMR experiments were conducted on a Bruker Avance
300 (1H, 300.13 MHz) spectrometer. 1H chemical shifts are
referenced to residual solvent protons; 13C spectra were referenced
to CDCl3 or C6D6. Signal assignment was done according to H,H-
and C,H-COSY and NOE measurements. Electron impact (EI) mass
spectra were taken on a Finnigan-MAT 95 spectrometer. IR spectra
were recorded on a BIO-RAD FTS-7 spectrometer using KBr
pellets. Elemental analyses were carried out by the Analytische
Laboratorien GmbH, Lindlar (Germany). Melting points were
determined using a “Mel-Temp” by Laboratory Devices, Cam-
bridge.
X-ray Diffraction. Single-crystal experiments were performed
on a Stoe IPDS diffractometer with graphite-monochromated Mo
KR radiation (λ ) 0.71073 Å). The structures were solved by direct
phase determination and refined by full-matrix least-squares
techniques against F2 with the SHELXL-97 program system.41
Crystallographic details are given in Table 5.
Modified Synthesis of Bis(phenanthren-9-yl)methanol.19
A
solution of 50 g (194 mmol) of 9-bromophenanthrene in 80 mL of
THF is dropped within 20 min onto a 4.7 g (196 mmol) portion of
magnesium turnings under vigorous stirring. Heat evolves, and for
reaction’s completeness the mixture is stirred overnight. Subse-
quently, a solution of 6.1 mL (99 mmol) of methylformiate in 25
mL of THF is added to the reaction mixture within 20 min,
whereupon the solution turned from green to brown. After 2 h the
reaction mixture is poured into 200 mL of 2 M HCl, yielding a
(39) Schellenberg, J. Macromol. Mater. Eng. 2005, 290, 675-680.
(40) Kamigaito, M.; Sawamoto, M.; Higashimura, T. Macromolecules
1995, 28, 5671-5675.
(41) Sheldrick, G. M. SHELXL-97. A Program for Refining Crystal
Structures; University of Go¨ttingen: Germany, 1997; unpublished.

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3833
Table 3. Comparison of Selected Bond Lengths and Torsion Angles
4b
5
6
10
11
15
16
a, b, c, d [deg]
Ct-Ti [Å]
22.3(2)
30.4(4)
22.2(3)
22.4(4)
2.120
21.3(4)
2.049
11.7(5)
2.069
13.3(4)
2.067
Table 4. Polymerization of Styrene (30 °C, styrene/MAO/
TIBA/Ti ) 700 000/110/25/1)
C-22), 134.2 (C-5), 133.3 (C-19), 130.8 (C-27), 130.5 (C-25), 129.5
(C-26), 128.5 (C-3), 128.3 (C-2), 127.6 (C-28), 127.3 (C-7), 127.0,
127.0 (C-6, C-8), 126.7 (C-14, C-15), 126.4 (C-10), 126.3 (C-9),
125.9 (C-5), 125.2 (C-11), 125.0 (C-1), 124.7 (C-16), 123.7 (C-4),
123.6, 123.3 (C-13, C-12), 121.3 (C-17), 53.2 (C-23). IR (KBr)
[cm-1]: ν˜ 3057 (m), 933 (m), 1690 (m), 1603 (m), 1497 (s), 1436
(m), 1381 (m), 1324 (m), 1264 (m), 1228 (m), 1160 (w), 1094
(w), 1040 (w), 933 (w), 856 (w), 742 (s), 618 (w), 517 (w), 436
(w). MS (EI, 70 eV): m/z (relative intensity) 366.0 (100) [M+],
181.9 (30), 175.4 (10).
polymerization time
[min]
melting pointb
run no.
catalyst
activitya
[°C]
1
2
3
4
5
6
7
8
11
10
15
15
16
16
17
17
120
120
60
120
60
120
60
120
1420
6040
6720
4720
3740
2000
3400
2000
267.2
268.0
266.2
265.6
266.4
266.2
266.0
267.0
Synthesis of TbfLi(THF)4 (5). To a suspension of 2.5 g (6.82
mmol) of 8bH-tetrabenzo[a,c,g,i]fluorene (4a) in 50 mL of THF is
added 4.4 mL (7.04 mmol) of n-butyllithium in n-hexane (1.6 M),
whereupon a dark orange solution is formed, which is cooled to
-80 °C to give 7.93 g of 4 as orange-yellow crystals (11.04 mmol,
a Activity in kg sPS/(mol Ti × mol styrene × h). b Melting point of the
polymer.
sticky white precipitate, which is filtered and washed with 100 mL
of water and 200 mL of diethyl ether. Afterward the product is
dried in vacuo, giving 31.6 g (82.2 mmol, 84. 6%) of bis-
(phenanthren-9-yl)methanol. Mp: 235 °C. 1H NMR (CDCl3, 500.13
MHz, 300 K) [ppm]: δ 8.78 (d, 2 H, H-5, H-5b), 8.70 (d, 2 H,
H-4, H-4b), 8.12 (d, 2 H, H-8, H-8b), 7.811 (s, 2 H, H-10, H-10b),
7.74 (d, 2 H, C-1, C-1b), 7.68-7.64 (m, 4 H, H-), 7.54 (m, 4 H,),
7.308 (s, 1 H, CHOH). 13C NMR (CDCl3, 124.75 MHz, 300 K)
[ppm]: δ 136.4 (C-14, C-14b), 131.4 (C-11, C-11b), 131.0 (C-13,
C-13b), 130.5 (C-12, C-12b), 130.1 (C-9, C-9b), 129.1 (C-1, C-1b),
127.0, 126.8 (C-2, C-2b, C-7, C-7b), 126.5 (C-3, C-3b, C-5, C-5b),
126.2 (C-10, C-10b), 124.4 (C-8, C-8b), 123.3 (C-5, C-5b), 122.5
(C-4, C-4b), 69.9 (CHOH). IR (KBr) [cm-1]: ν˜ 3540 (s), 3464
(s), 3072 (s), 1938 (m), 1802 (m), 1604 (s), 1489 (m), 1441 (m),
1401 (m), 1243 (m), 1210 (m), 1066 (s), 1036 (s), 965 (m), 906
(m), 889 (m), 802 (m), 751 (s), 718 (s). MS (EI, 70 eV): m/z
(relative intensity) 384.1 (70) [M+], 365.1 (10) [M - OH], 205.2
(100), 178.2 (50).
Modified Synthesis of 8bH-Tetrabenzo[a,c,g,i]fluorene (4a).19
To a suspension of 28.9 g (75.14 mmol) of bis(phenanthren-9-yl)-
methanol in 250 mL of dichloromethane is added 50 mL of
trifluoroacetic acid within 20 min. After stirring overnight the
yellow suspension is evaporated to dryness and 200 mL of
chloroform is added. The mixture is refluxed for 30 min and filtered
after cooling to ambient temperature in order to remove residual
trifluoroacetic acid. The yellow precipitate is dried in vacuo,
yielding 18.7 g of product (51 mmol, 68%). Mp: 277 °C. 1H NMR
(CDCl3, 500.13 MHz, 300 K) [ppm]: δ 8.79 (m, 2 H, H-12, H-13),
8.26 (m, 1 H, H-16), 8.09 (dd, 1 H, 3JHH ) 7.4 Hz, 4JHH ) 1.5 Hz,
H-9), 7.97 (m, 1 H, 3JHH ) 7.4 Hz, 4JHH ) 1.2 Hz, H-4), 7.84 (m,
1
81%). Mp: 81 °C. H NMR (C6D6, 500.13 MHz, 300 K) [ppm]:
δ 9.30 (d, 2 H, 3JHH ) 8.2 Hz, H-8, H-9), 8.60 (d, 2 H, 3JHH ) 9.8
Hz, H-5, H-12), 8.59 (d, 2 H, H-4, H-13), 8.48 (d, 2 H, 3JHH ) 7.7
Hz, H-1, H-16), 7.690 (s, 1 H, H-17), 7.53 (m, 2 H, H-2, H-15),
7.48 (m, 2 H, H-7, H-10), 7.40 (m, 2 H, H-3, H-14), 7.35 (m, 2 H,
3
H-6, H-11), 2.95 (t, 16 H, JHH ) 7.4 Hz, OCH2), 1.04 (t, 16 H,
3JHH ) 7.4 Hz, OCH2CH2). 13C NMR (C6D6, 124.75 MHz, 300 K)
[ppm]: δ 133.0 (C-22, C-25), 131.8 (C-19, C-28), 129.3 (C-20,
C-27), 128.3 (C-21, C-26), 126.4 (C-2, C-15), 126.2 (C-7, C-10),
125.4 (C-18, C-29), 124.8 (C-8, C-9), 124.2 (C-5, C-12), 123.7
(C-1, C-16), 123.6 (C-4, C-13), 123.4 (C-3, C-14), 122.2 (C-6,
C-11), 112.6 (C-23, C-24), 87.4 (C-17), 67.7 (OCH2CH2), 25.2
(OCH2CH2). Anal. Calcd for C45H49LiO4: C, 81.79; H, 7.47.
Found: C, 82.04; H, 7.34.
Synthesis of TbfLi(DME)3 (6). To a solution of 1 g (2.73 mmol)
of 8bH-tetrabenzo[a,c,g,i]fluoren (4a) in 160 mL toluene is added
1.9 mL (3.04 mmol) of n-butyllithium in n-hexane. The reaction
mixture is stirred overnight, and the white precipitate is filtered
off, washed two times with 20 mL of toluene, and dried in vacuo.
Subsequently 300 mg (0.94 mmol) of tetrabenzo[a,c,g,i]fluorenyl-
lithium is dissolved in 80 mL of DME to form a bright yellow
solution, which is cooled to -20 °C to yield 315 mg (0.47 mmol,
1
50%) of yellow crystals. Melting point: 98 °C. H NMR (C6D6,
3
500.13 MHz, 300 K) [ppm]: δ 9.28 (d, 2 H, JHH ) 8.3 Hz, H-8,
3
3
H-9), 8.62 (d, 2 H, JHH ) 7.8 Hz, H-5, H-12), 8.60 (d, 2 H, JHH
3
) 7.8 Hz, H-4, H-13), 8.49 (d, 2 H, JHH ) 7.8 Hz, H-1, H-16),
7.67 (s, 1 H, H-17), 7.55 (m, 2 H, H-2, H-15), 7.48 (m, 2 H, H-7,
H-10), 7.41 (m, 2 H, H-4, H-14), 7.36 (m, 2 H, H-6, H-11), 2.72
(s, 12 H, CH2), 2.64 (s, 18 H, CH3). 13C NMR (C6D6, 124.75 MHz,
300 K) [ppm]: δ 137.5 (C-17), 132.9 (C-22, C-25), 131.6 (C-19,
C-28), 129.3 (C-20, C-26), 128.0 (C-21, C-27), 126.6 (C-2, C-15),
125.5 (C-18, C-29), 125.4 (C-7, C-10), 124.9 (C-8, C-9), 124.3
(C-5, C-12), 123.7, 123.7, 123.6 (C-1, C-16, C-4, C-13, C-3, C-14),
122.4 (C-6, C-11), 112.5 (C-23, C-24). Anal. Calcd for C41H47-
LiO3: C, 76.61; H, 7.37. Found: C, 78.19; H, 6.40.
3
3
4
1 H, JHH ) 7.5, H-5), 7.72 (dd, 1 H, JHH ) 7.2 Hz, JHH ) 1.6
Hz, H-1), 7.70-7.68 (m, 2 H, H-10, H-15), 7.66-7.63 (m, 2 H,
H-11, H-14), 7.46 (m, 1 H, 3JHH ) 7.7 Hz, H-8), 7.46 (d, 1 H, 4JHH
3
3
) 2.2 Hz, H-16), 7.42 (ddd, 1 H, JHH ) 7.4 Hz, JHH ) 7.4 Hz,
4JHH ) 1.5 Hz, H-3), 7.39 (ddd, 1 H, JHH ) 7.4 Hz, JHH ) 7.4
Hz, 4JHH ) 1.3 Hz, H-2), 7.32 (dd, 1 H, 3JHH ) 7.4 Hz, 3JHH ) 7.5
Hz, H-6), 7.11 (m, 1 H, 3JHH ) 7.5 Hz, 3JHH ) 7.5 Hz, H-7), 5.39
(m, 1 H, H-23). 13C NMR (CDCl3, 124.75 MHz, 300 K) [ppm]: δ
148.5 (C-18), 141.4 (C-29), 137.5 (C-24), 135.5, 135.4 (C-21,
3
3
Formation of Bis(17-tetrabenzo[a,c,g,i]fluorene) (7) by Reac-
tion of 4 with TiCl4(THF)2. To a solution of 455 mg (1.40 mmol)
of TiCl4(THF)2 in 50 mL of THF is added 925 mg (1.40 mmol) of

Table 5. Crystal Structure Data for Compounds 4b, 5-7, 10, 11, 13, 15, and 16
4b
5
6
7
10
11
13
15
16
empirical formula
fw
color
C
29H18
C45H49LiO4
660.78
yellow
C41H47LiO6‚0.25C4H10O2 C58H34‚C2H2Cl2
C38H38O3Ti
590.58
yellow
C32H24Cl2OTi
543.31
red
C50H58Cl2O8Ti
953.66
orange-red
C47H32O3Ti
692.63
yellow
C50H38O3Ti
734.70
yellow
366.43
yellow
665.26
815.78
yellow
orange-yellow
cryst dimens, mm
cryst syst
space group
a, Å
b, Å
c, Å
R, deg
â, deg
γ, deg
V, Å3
1.20 × 0.19 × 0.10 0.50 × 0.34 × 0.33 1.10 × 0.45 × 0.15
0.30 × 0.24 × 0.18 0.45 × 0.43 × 0.42 0.40 × 0.31 × 0.28 0.55 × 0.29 × 0.24 0.28 × 0.21 × 0.09 0.32 × 0.20 × 0.19
monoclinic
P2/c
triclinic
triclinic
monoclinic
P21/n
orthorhombic
Pbca
monoclinic
P21/n
monoclinic
P21/c
monoclinic
P21/n
triclinic
P1h
P1h
P1h
18.4562(14)
5.0962(2)
19.1459(16)
90
91.022
90
12.8899(11)
17.0343(13)
18.0571(13)
106.810(8)
96.169(9)
105.422(9)
3585.0(5)
4
12.2073(6)
13.4821(7)
23.8558(14)
75.144(6)
76.299(6)
82.717(6)
3677.8(3)
4
13.8807(8)
20.0576(8)
14.8992(10)
90
110.980
90
16.4719(8)
17.0792(7)
22.1152(14)
90
90
90
12.9702(6)
10.6352(7)
18.6582(9)
90
93.630(6)
90
11.9750(4)
23.7536(7)
8.4337(2)
90
92.273
90
14.2737(9)
15.7569(8)
15.2020(8)
90
99.529(7)
90
10.0203(5)
13.5219(8)
14.6028(8)
87.455(7)
75.017(6)
77.620(6)
1866.75(18)
2
1800.5(2)
4
3873.1(4)
4
6221.6(6)
8
2568.6(2)
4
2397.07(12)
2
3371.9(3)
4
Z
D
calcd, g cm3
1.352
1.224
1.201
1.399
1.261
1.404
1.321
1.364
1.307
µ, mm-1
T, K
0.077
0.076
0.079
0.212
0.311
0.566
0.496
0.299
0.274
153
153
153
153
153
153
153
153
153
θ range, deg
1.38 to 26.00
no. of rflns collected 14 846
2.25 to 26.05
40 561
2.10 to 26.04
45 760
2.50 to 26.05
31 892
2.47 to 25.99
49 297
2.21 to 26.03
21 824
2.42 to 26.00
23 709
2.14 to 26.04
33 096
2.10 to 26.10
23 098
no. of indep rflns
3328 [R(int) )
0.0446]
13 147 [R(int) )
0.0807]
13 458 [R(int) )
0.0572]
7507 [R(int) )
0.0617]
5898 [R(int) )
0.0805]
4713 [R(int) )
0.0538]
4497 [R(int) )
0.0387]
6618 [R(int) )
0.1291]
6847 [R(int) )
0.0598]
no. of rflns I > 2σ(I) 2514
6785
none
0.9754 and 0.9630
R1 ) 0.0463,
wR2 ) 0.0910
R1 ) 0.1059,
wR2 ) 0.1054
8856
none
09882 and 0.9180
R1 ) 0.0383,
wR2 ) 0.0826
R1 ) 0.0676,
wR2 ) 0.0906
4918
3801
3416
3793
3348
none
0.9736 and 0.9210
R1 ) 0.0399,
wR2 ) 0.0608
R1 ) 0.1121,
wR2 ) 0.0732
4553
abs corr
none
numerical
0.9628 and 0.9390
R1 ) 0.0364,
wR2 ) 0.0763
R1 ) 0.0668,
wR2 ) 0.0835
numerical
0.8805 and 0.8727
R1 ) 0.0472,
wR2 ) 0.1193
R1 ) 0.0779,
wR2 ) 0.1306
numerical
0.8577 and 0.8054
R1 ) 0.0321,
wR2 ) 0.0742
R1 ) 0.0517,
wR2 ) 0.0796
numerical
0.8902 and 0.7720
R1 ) 0.0298,
wR2 ) 0.0822
R1 ) 0.0369,
wR2 ) 0.0847
numerical
0.9498 and 0.9175
R1 ) 0.0363,
wR2 ) 0.0758
R1 ) 0.0646,
wR2 ) 0.0823
max., min. transmn
final R indices
(I > 2σ(I))
0.9924 and 0.9137
R indices (all data)

Tetrabenzofluorenyllithium and -titanium Complexes
Organometallics, Vol. 25, No. 16, 2006 3835
solid 5 at -78 C. The reaction mixture was slowly warmed to
ambient temperature, whereupon 7 precipitated nearly quantitatively
as an orange-yellow solid, which was isolated on a glass frit and
dried in vacuo. Crystals suitable for X-ray diffraction were obtained
by recrystallization from dichloromethane. Mp: 363 °C dec. IR
(KBr) [cm-1]: ν˜ 3070 (m), 2920 (w), 2327 (w), 1931 (w), 1701
(w), 1606 (w), 1495 (m), 1423 (m), 1327 (m), 1263 (m), 1232 (m),
1157 (m), 1107 (m), 1040 (m), 935 (w), 857 (w), 727 (s), 617 (w),
521 (w), 433 (w). MS (EI, 70 eV): m/z (relative intensity) 730.2
(40) [M+], 365.2 (100) [M2+].
solution with 40 mL of n-hexane yields 5.30 g (10.5 mmol, 39%)
1
of 12 as dark red crystals. Mp: 95 °C. H NMR (CDCl3, 500.13
MHz, 300 K) [ppm]: δ 7.16 (t, 6 H, 3JHH ) 6.9 Hz, Hmeta), 6.98-
3
6.93 (m, 9 H, Hpara, Hortho), 4.14 (t, 4 H, JHH ) 6.2 Hz, OCH2-
3
CH2), 1.95 (q, 4 H, JHH ) 6.2 Hz). 13C NMR (CDCl3, 124.75
MHz, 300 K) [ppm]: δ 166.5, 166.4, 166.3 (Cipso), 128.9 (Cmeta),
128.0, 127.8, 127.6, 123.1 (Cpara), 119.4 (Cortho), 71.2 (OCH2CH2),
25.5 (OCH2CH2). MS (EI, 70 eV): m/z (relative intensity) 419.7
(100), 361.7 (95), 236.8 (55), 268.8 (35), 232.8 (60), 156.8 (15),
93.9 (50), 76.9 (15). IR (KBr) [cm-1]: ν˜ 2970 (m), 1939 (w), 1586
(s), 1477 (s), 1362 (s), 1160 (m), 1068 (s), 1020 (s), 999 (s), 900
(s), 820 (s), 756 (s), 688 (s), 667 (s), 617 (s)559 (s), 486 (s), 459
(s), 444 (s). Anal. Calcd for C44H46Cl2O8Ti2: C, 60.78; H, 5.33.
Found: C, 60.51; H, 5.46
Synthesis of TbfTi(OiPr)3 (10). A portion of 660 mg (1.00
mmol) of 5 and 260 mg (1.00 mmol) of ClTi(OiPr)3 are mixed as
solids, and 60 mL of toluene is added. After stirring overnight the
reaction mixture is taken to dryness and the residue is extracted
with 60 mL of n-hexane. Cooling the yellow solution to -80 °C
yields 402 mg (0.68 mmol, 68%) of 7 as yellow crystals. Mp: 135
Synthesis of [(4-MeC6H4O)3Ti(Cl)(THF)]2 (13). To a solution
of 10.00 g (92.47 mmol) of 4-methylphenol in 50 mL of toluene is
added 3.40 mL (30.82 mmol) of TiCl4, and the mixture is refluxed
overnight. The deep red reaction mixture is taken to dryness, and
the residue is dissolved in a minimum amount (ca. 80 mL) of THF.
Layering the solution with 80 mL of n-hexane affords 11.56 g
(12.13 mmol, 82.7%) of 13 as deep red crystals suitable for X-ray
1
°C. H NMR (C6D6, 500.13 MHz, 300 K) [ppm]: δ 9.14 (d, 2 H,
3JHH ) 7.9 Hz, H-8, H-9), 8.43 (d, 2 H, 3JHH ) 7.9 Hz, H-5, H-12),
8.41 (d, 2 H, 3JHH ) 8.1 Hz, H-4, H-13), 8.24 (d, 2 H, 3JHH ) 7.7
3
Hz, H-1, H-16), 7.596 (s, 1 H, H-17), 7.47 (m, 2 H, JHH ) 7.3
Hz, H-2, H-15), 7.43-7.37 (m, 6 H, H-3, H-6, H-7, H-10, H-14,
3
1
H-11), 3.86 (q, 3 H, JHH ) 6.1 Hz, OCH(CH3)2), 0.58 (d, 18 H,
diffraction. Mp: 109 °C. H NMR (CDCl3, 500.13 MHz, 300 K)
3JHH ) 6.1 Hz, OCH(CH3)2). 13C NMR (C6D6, 124.75 MHz, 300
K) [ppm]: δ 131.2 (C-19, C-28), 130.6 (C-22, C-26), 129.5 (C-
20, C-27), 128.3 (C-21, C-26), 127.4 (C-8, C-9), 127.1 (C-2, C-15),
126.7, 126.1, 125.7 (C-3, C-6,C-7, C-10, C-11, C-14), 125.6 (C-
18, C-29), 124.9 (C-1, C-16), 124.2 (C-5, C-12), 123.6 (C-4, C-13),
116.9 (C-23, C-24). MS (EI, 70 eV): m/z (relative intensity) 598.8
(90) [M - H], 531 (20), 472.8 (30), 428.7 (35), 365.8 (95), 268.9
(100), 224.9 (45), 180.9 (30), 138.9 (25). IR (KBr) [cm-1]: ν˜ 3077
(m), 2966 (s), 2923 (s), 2856 (m), 1604 (m), 1510 (m), 1434 (s),
1373 (m), 1326 (s), 977 (s), 848 (s), 794 (m), 751 (s), 721 (s), 594
(s). Anal. Calcd for C38H38O3Ti: C, 77.28; H, 6.49; O, 8.13.
Found: C, 77.30; H, 5.21.
[ppm]: δ 6.95 (d, 6 H, 3JHH ) 7.6 Hz, Hmeta), 6.84 (m, 6 H, Hortho),
4.12 (t, 4 H, 3JHH ) 6.2 Hz, OCH2CH2), 2.228 (s, 9 H, CH3), 1.94
3
(q, 4 H, JHH ) 6.2 Hz). 13C NMR (CDCl3, 124.75 MHz, 300 K)
[ppm]: δ 164.9 (Cipso), 129.2 (Cmeta), 119.1 (Cortho), 70.9 (OCH2-
CH2), 25.5 (OCH2CH2), 20.8 (CH3). MS (EI, 70 eV): m/z (relative
intensity) 476.0 (25), 403.9 (100), 368.9 (15), 331.8 (30), 296.9
(30), 260.9 (20), 204.9 (10), 107.0 (90), 91.0 (35), 77.0 (25), 65.0
(10), 51.0 (10). IR (KBr) [cm-1]: ν˜ 2915 (m), 1603 (m) 1577 (m),
1498 (s), 1251 (s), 1206 (s), 1165 (m), 1101 (m), 1025 (m), 903
(s), 831 (s), 787 (s), 757 (m), 643 (w), 592 (s), 575 (s), 558 (s),
463 (s), 416 (s). Anal. Calcd for C50H58Cl2O8Ti2: C, 62.97; H,
6.13. Found: C, 62.96; H, 6.40.
Synthesis of TbfTiCl2(iPrO) (11). A portion of 661 mg (1.00
mmol) of 5 and 213 mg (1.00 mmol) of Cl3Ti(OiPr) (9) are mixed
as solids, and 40 mL of toluene is added, whereupon a red
suspension is formed immediately. After 2 h the reaction mixture
is filtered through a P4 glass frit. Layering the solution with 40
mL of n-hexane afforded red crystals of 11 (124 mg, 23%). Mp:
208 °C. 1H NMR (CDCl3, 500.13 MHz, 300 K) [ppm]: δ 8.85 (d,
Synthesis of [(4-tBuC6H4O)3Ti(Cl)(THF)]2 (14). To a solution
of 3.25 g (21.64 mmol) of 4-tert-butylphenol in 40 mL of toluene
is added 0.80 mL (7.11 mmol) of TiCl4, and the mixture is refluxed
overnight. The deep red reaction mixture is evaporated to dryness
and the residue dissolved in 40 mL of THF. Layering the solution
with 40 mL of n-hexane yielded 2.73 g (2.27 mmol, 63.8%) of 14
as red microcrystals. Mp: 125 °C. 1H NMR (CDCl3, 500.13 MHz,
300 K) [ppm]: δ 7.09 (d, 8 H, 3JHH ) 6.2 Hz, Hmeta), 7.00 (d, 4 H,
3JHH ) 7.8 Hz, Hmeta bridge), 6.77 (m, 8 H, Hortho), 6.55 (d, 2 H, 3JHH
) 6.2 Hz, Hortho bridge), 6.48 (d, 2 H, Hortho bridge), 4.00 (t, 8 H, 3JHH
3
2 H, 3JHH ) 8.1 Hz, H-8, H-9), 8.63 (d, 2 H, JHH ) 8.2 Hz, H-5,
H-12), 8.60 (d, 2 H, 3JHH ) 5.3 Hz, H-4, H-13), 8.39 (d, 2 H, 3JHH
) 8.4 Hz, H-1, H-16), 8.014 (s, 1 H, H-17), 7.72-7.67 (m, 6 H,
3
3
H-2, H-3, H-6, H-11, H-14, H-15), 7.60 (m, 2 H, JHH ) 7.6 Hz,
) 6.4 Hz, OCH2CH2), 1.90 (q, 8 H, JHH ) 6.4 Hz, OCH2CH2),
3
t
t
t
H-7, H-10), 3.42 (q, 1 H, JHH ) 6.1 Hz, OCH(CH3)2), 0.41 (d, 6
1.243 (s, 36 H, Bu), 1.221 (s, 9 H, Bu bridge), 1.209 (s, 9 H, Bu
bridge). 13C NMR (CDCl3, 124.75 MHz, 300 K) [ppm]: δ 164.8
(Cipso), 145.9 (Cpara), 145.8 (Cpara bridge), 125.5 (Cmeta), 125.4 (Cmeta
bridge), 118.8 (Cortho), 118.7 (Cortho bridge), 70.3 (OCH2CH2), 34.3
(C(CH3)), 31.5 (C(CH3)), 25.5 (OCH2CH2). MS (EI, 70 eV): m/z
(relative intensity) 643.9 (55), 628.9 (55), 529.8 (30), 514.9 (90),
400.8 (15), 341.0 (45), 306.9 (30), 249.9 (15), 232.8 (10), 150.0
(25), 135.0 (100), 107.0 (25), 95.0 (10). IR (KBr) [cm-1]: ν˜ 3252
(m), 2961 (s), 2900 (m), 2865 (m), 1599 (w), 1503 (s), 1459 (m),
1391 (w), 1362 (m), 1256 (s), 1219 (m), 1175 (m), 1110 (m), 1019
(m), 910 (s), 869 (s), 831 (s), 721 (m), 681 (w), 641 (w), 577 (m),
549 (m), 527 (s), 475 (w), 446 (w). Anal. Calcd for C68H94Cl2O8-
Ti2: C, 67.72; H, 7.86. Found: C, 67.52, H, 7.72.
3
H, JHH ) 6.1 Hz, OCH(CH3)2). 13C NMR (CDCl3, 124.75 MHz,
300 K) [ppm]: δ 131.7 (C-19, C-28), 131.2 (C-22, C-25), 128.6
(C-21, C-26), 127.9 (C-8, C-9), 127.6 (C-20, C-27), 127.5 (C-18,
C-29), 126.3 (C-7, C-10), 125.1 (C-1, C-16), 124.3 (C-5, C-12),
123.6 (C-4, C-13), 122.3 (C-23, C-24), 101.3 (C-17), 85.4 (OCH-
(CH3)2), 23.2 (OCH(CH3)2). MS (EI, 70 eV): m/z (relative intensity)
541.7 (20) [M+], 364.9 (100). IR (KBr) [cm-1]: ν˜ 3076 (w), 2986
(w), 2924 (w), 1507 (w), 1430 (w), 1164 (w), 1107 (s), 1017 (s),
862 (w), 818 (w), 754 (s), 721 (m), 607 (w), 426 (w). Anal. Calcd
for C32H24Cl2OTi: C, 77.28; H, 6.49; O, 8.13. Found: C, 74.68
(lowered by TiC formation); H, 5.92. Isotope pattern for C32H24-
Cl2OTi m/z (relative intensity): calcd 542.1 (100), 544.1 (72), 543.1
(48), 545.1 (29); found 542.1 (100), 544.1 (75), 544.1 (50), 545.1
(30).
Synthesis of TbfTi(OC6H5)3 (15). A portion of 330 mg (0.50
mmol) of 5 and 220 mg (0.25 mmol) of 12 are mixed as solids and
suspended in 30 mL of cyclohexane. The reaction mixture is stirred
overnight and filtered through a glass frit. Layering the orange
solution with 30 mL of n-hexane yielded 121 mg (0.18 mmol, 35%)
of 15 as red crystals suitable for X-ray diffraction. Mp: 153 °C.
1H NMR (CDCl3, 500.13 MHz, 300 K) [ppm]: δ 8.81 (d, 2 H,
3JHH ) 8.0 Hz, H-8, H-9), 8.41 (d, 2 H, 3JHH ) 8.0 Hz, H-5, H-12),
Synthesis of [(C6H5O)3Ti(Cl)(THF)]2 (12). To 4.56 g (20 mmol)
of titanium tetraethoxide is added a solution of 7.53 g (80 mmol)
of phenol, and the resulting ethanol is distilled from the reaction
mixture. The red solution is taken to dryness, the residue is dissolved
in 80 mL of dichloromethane, and the color deepens as 0.73 mL
(6.67 mmol) of TiCl4 is added. After stirring for 2 h all volatiles
are evaporated and 40 mL of THF is added. Layering the deep red
3
3
8.38 (d, 2H, JHH ) 8.0 Hz, H-4, H-13), 8.14 (d, 2 H, JHH ) 6.9

3836 Organometallics, Vol. 25, No. 16, 2006
Schro¨der et al.
Hz, H-1, H-16), 7.80 (s, 1 H, H-17), 7.60 (m, 2 H, H-2, H-15),
7.56 (m, 2 H, H-7, H-10), 7.53 (m, 2 H, H-3, H-14), 7.48 (m, 2 H,
Hpara), 1.228 (s, 27 H, C(CH3)3). 13C NMR (CDCl3, 125.75 MHz,
300 K) [ppm]: δ 162.8 (Cipso), 143.2 (Cpara), 131.4 (C-22, C-25),
131.2 (C-19, C-28), 128.6 (C-20, C-27), 127.7 (C-21, C-26), 127.4
(C-2, C-15), 127.3 (C-7, C-10), 127.2 (C-18, C-29), 127.1 (C-8,
C-9), 127.0 (C-5, C-12), 125.8 (C-1, C-16), 125.1 (Cmeta), 124.8
(C-4, C-13), 124.2 (C-3, C-14), 123.5 (C-7, C-10), 119.1 (C-23,
C-24), 117.6 (Cortho), 97.2 (C-17), 34.1 (C(CH3)3), 31.6 (C(CH3)3).
MS (EI, 70 eV): m/z (relative intensity) 679 (10), 617 (10), 366.1
(35) [Tbf+], 150.1 (25) [4-tBuC6H5O+], 135.1 (100), 107.1 (20).
IR (KBr) [cm-1]: ν˜ 3030 (w), 2958 (m), 2902 (m), 2864 (m), 1599
(m), 1502 (s), 1460 (m), 1438 (m), 1248 (s), 1248 (m), 1174 (s),
1108 (m), 908 (m), 834 (s), 807 (m), 756 (s), 721 (s), 567 (m),
550 (m), 430 (w). Anal. Calcd for C59H56O3Ti: C, 82.31; H, 6.56.
Found: C, 82.52; H, 6.72.
Styrene Polymerization. A catalyst premix solution was pre-
pared by using the corresponding transition metal catalyst together
with methylalumoxane (MAO) as cocatalyst with a molar ratio of
MAO/triisobutylaluminum (TIBA)/Ti ) 110/25/1. The mixture was
composed in a drybox under argon atmosphere in a 5 mL volumetric
flask by adding sequentially 1.17 mL of 1.41 M MAO solution in
toluene, 0.38 mL of a 1 M TIBA solution in toluene, 14.9 µmol of
neat tetrabenzo[a,c,g,i]fluorenyltitanium catalysts (10, 11, 15, 16,
17), and sufficient additional toluene to 5 mL volume. To run the
polymerization trials, glass ampules were charged in a drybox with
10 mL of styrene that had previously been deoxygenated by
sparging with nitrogen, passed through activated alumina, and
hydrogenated using Pd on alumina to remove phenylacetylene. After
removal from the drybox the septum-capped, crimp-sealed ampules
were placed in a water bath and equilibrated for 10 min at the
polymerization temperature of 30 °C. Polymerizations were initiated
at a molar ratio styrene/Ti ) 700 000/1, by addition of 41.6 µL of
the catalyst premix solution described above via microliter syringe.
After the desired polymerization time of 60 or 120 min, respectively,
the polymerization reactions were quenched by the addition of
methanol. The resulting polymer was isolated and dried under
vacuum for 30 min at 150 °C followed by 30 min at 250 °C. The
samples were weighed and melting points were determined by DSC.
Additional crystallographic data for the structures 4b, 5, 6, 7,
10, 11, 13, 15, and 16 have been deposited with the Cambridge
Data Centre as supplementary publications nos. CCDC 601752 (4b),
CCDC 601753 (5), CCDC 601749 (6), CCDC 601754 (7), CCDC
601751 (10), CCDC 601750 (11), CCDC 601746 (13), CCDC
601748 (15), and CCDC 601747 (16). Copies of the data can be
obtained free of charge on application to CCDC, 12 Union Road,
Cambridge CB21EZ, U.K. (fax (+44)1223-336-033; e-mail
deposit@ccdc.cam.ac.uk).
3
H-6, H-11), 6.85 (dd, 6 H, JHH ) 7.7 Hz, H meta), 6.68 (t, 3 H,
3
3JHH ) 7.7 Hz, H para), 5.95 (d, 6 H, JHH ) 7.7 Hz, H ortho). 13C
NMR (CDCl3, 124.75 MHz, 300 K) [ppm]: δ 164.9 (Cipso), 131.5
(C-22, C-25), 131.2 (C-19, C-28), 128.5 (Cmeta), 128.0 (C-20, C-27),
127.5 (C-21, C-26), 127.5 (C-2, C-15), 127.3 (C-7, C-10), 127.3
(C-18, C-29), 127.2 (C-8, C-9), 127.2 (C-5, C-12), 126.0 (C-1,
C-16), 124.7 (C-4, C-13), 124.3 (C-3, C-14), 123.6 (C-6, C-11),
120.8 (Cpara), 119.4 (C-23, C-24), 118.3 (Cortho), 97.4 (C-17). MS
(EI, 70 eV): m/z (relative intensity) 692.2 (10) [M+], 420.1 (65),
366.1 (100) [Tbf+], 327.1 (45), 233.0 (50), 94.0 (15) [PhO+], 77.0
(30) [C6H5+], 63.9 (40). IR (KBr) [cm-1]: ν˜ 3058 (w), 2962 (w),
2921 (w), 2849 (w), 1577 (s), 1477 (s), 1245 (s), 1153 (m), 1098
(m), 1060 (m), 1020 (m), 896 (s), 869 (s), 816 (m), 750 (s), 685
(m), 643 (s). Anal. Calcd for C47H32O3Ti: C, 81.50; H, 4.66; O,
6.93. Found: C, 80.68; H, 5.93.
Synthesis of TbfTi(4-MeC6H4O)3 (16). A portion of 330 mg
(0.50 mmol) of 5 and 240 mg (0.25 mmol) of 13 are mixed as
solids and suspended in 30 mL of cyclohexane. The reaction mixture
is stirred overnight and filtered through a glass frit. Layering the
orange solution with 30 mL of n-hexane yielded 105 mg (105 mg,
29%) of 16 as red crystals suitable for X-ray diffraction. Mp: 154
°C. 1H NMR (CDCl3, 500.13 MHz, 300 K) [ppm]: δ 8.83 (d, 2 H,
3JHH ) 8.0 Hz, H-8, H-9), 8.45 (d, 2 H, 3JHH ) 8.2 Hz, H-5, H-12),
8.43 (d, 2 H, 3JHH ) 8.3 Hz, H-4, H-13), 8.16 (d, 2 H, 3JHH ) 7.8
Hz, H-1, H-16), 7.795 (s, 1 H, H-17), 7.63 (m, 2 H, H-2, H-15),
7.59 (m, 2 H, H-7, H-10), 7.56 (m, 2 H, H-3, H-14), 7.50 (m, 2 H,
H-6, H-11), 6.66 (d, 6H, 3JHH ) 8.1 Hz, Hmeta), 5.88 (d, 6 H, 3JHH
) 8.1 Hz, Hortho), 2.19 (s, 9 H, CH3). 13C NMR (CDCl3, 125.75
MHz, 300 K) [ppm]: δ 164.9 (Cipso), 131.5 (C-22, C-25), 131.2
(C-19, C-28), 128.5 (Cmeta), 128.0 (C-20, C-27), 127.5 (C-21, C-26),
127.5 (C-2,C-15), 127.3 (C-7, C-10), 127.3 (C-18, C-29), 127.2
(C-8, C-9), 127.2 (C-5, C-12), 126.0 (C-1, C-16), 124.7 (C-4, C-13),
124.3 (C-3, C-14), 123.6 (C-6, C-11), 120.8 (Cpara), 119.1 (C-23,
C-24), 117.9 (Cortho), 97.4 (C-17), 26.9 (CH3). MS (EI, 70 eV):
m/z (relative intensity) 629.0 (20), 579.0 (20), 479.0 (15), 366.1
(15) [Tbf+], 276.0 (45), 151.0 (40), 84.1 (100). IR (KBr) [cm-1]:
ν˜ 3019 (w), 2918 (w), 2853 (w), 1603 (w), 1499 (s), 1434 (m),
1275 (s), 1251 (s), 1163 (m), 1099 (m), 928 (w), 880 (s), 819 (m),
781 (m), 755 (m), 723 (m), 642 (w), 582 (m), 510 (m), 418 (w).
Anal. Calcd for C50H38O3Ti: C, 81.74; H, 5.21; O, 6.53. Found:
C, 81.42; H, 5.15.
Synthesis of TbfTi(4-tBuC6H4O)3 (17). A portion of 330 mg
(0.50 mmol) of 5 and 300 mg (0.25 mmol) of 14 are mixed as
solids and suspended in 30 mL of cyclohexane. The reaction mixture
is stirred overnight and filtered through a P4 glass frit. Layering
the orange solution with 30 mL of n-hexane yielded 114 mg (0.13
mmol, 27%) of 17 as orange microcrystals. Mp: 173 °C. 1H NMR
Acknowledgment. This work was supported by DOW
Central Germany and by the Fonds der Chemischen Industrie.
3
(CDCl3, 500.13 MHz, 300 K) [ppm]: δ 8.81 (d, 2 H, JHH ) 7.4
3
Hz, H-8, H-9), 8.36 (d, 2 H, JHH ) 8.0 Hz, H-5, H-12), 8.33 (d,
Supporting Information Available: Additional crystallographic
data for the structures 4b, 5, 6, 7, 10, 11, 13, 15, and 16 are available
free of charge via the Internet at http://pubs.acs.org.
2 H, 3JHH ) 7.7 Hz, H-4, H-13), 8.14 (d, 2 H, 3JHH ) 7.0 Hz, H-1,
H-16), 7.793 (s, 1 H, H-17), 7.58 (m, 2 H, H-2, H-15), 7.54 (m, 2
H, H-7, H-10), 7.51 (m, 2 H, H-3, H-14), 7.48 (m, 2 H, H-6, H-11),
3
3
6.83 (d, 6 H, JHH ) 8.6 Hz, Hmeta), 5.89 (d, 6 H, JHH ) 8.6 Hz,
OM0602613