O-Phenylene-bridged Cp/sulfonamido titanium complexes for ethylene/1-octene copolymerization

Article abstract of DOI:10.1039/b605345a

The Suzuki-coupling reaction of 2-(dihydroxyboryl)-3,4-dimethyl-2- cyclopenten-1-one (1) and 2-(dihydroxyboryl)-3-methyl-2-cyclopenten-1-one (2) with 2-bromoaniline derivatives affords cyclopentenone compounds (3-8) from which cyclopentadiene compounds, 4,6-R′₂-2-(2,5-Me ₂C₅H₃)C₆H₂NH₂ (9-11) and 4,6-R′₂-2-(2,3,5-Me₃C₅H ₂)C₆H₂NH₂ (12-14) are prepared. After sulfonation of the -NH₂ group with p-TsCl, metallation is carried out by successive addition of Ti(NMe₂)₄ and Me₂SiCl₂ affording o-phenylene-bridged Cp/sulfonamido titanium dichloride complexes, [4,6-R′₂-2-(2,5-Me ₂C₅H₂)C₆H₂NSO ₂C₆H₄CH₃)]TiCl₂ (R′ = H, 21; R′ = Me, 22; R′ = F, 23) and [4,6-R′₂-2- (2,3,5-Me₃C₅H)C₆H₂NSO ₂C₆H₄CH₃)]TiCl₂ (R′ = H, 24; R′ = Me, 25; R′ = F, 26). The molecular structures of 24 and [2-(2,5-Me₂C₅H₂)C₆H ₄NSO₂C₆H₄CH₃)]Ti(NMe ₂)₂ (27) are determined by X-ray crystallography. The Cp(centroid)-Ti-N angle in 24 is smaller (100.90°) than that observed for the CGC (constrained-geometry catalyst), [Me₂Si(η⁵- Me₄Cp)(N^tBu)]TiCl₂ (107.6°) indicating a more "constrained feature" in 24 than in the CGC. Complex 24 shows the highest activity among the newly prepared complexes in ethylene/1-octene copolymerization but it is slightly inferior to the CGC in terms of activity, comonomer-incorporation ability, and molecular weight of the obtained polymers. The Royal Society of Chemistry 2006.

Full text of DOI:10.1039/b605345a

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PAPER
www.rsc.org/dalton | Dalton Transactions
o-Phenylene-bridged Cp/sulfonamido titanium complexes for
ethylene/1-octene copolymerization†
Dae June Joe,a Chun Ji Wu,a Taekki Bok,a Eun Jung Lee,b Choong Hoon Lee,b Won-Sik Han,c
Sang Ook Kangc and Bun Yeoul Lee*a
Received 13th April 2006, Accepted 20th June 2006
First published as an Advance Article on the web 3rd July 2006
DOI: 10.1039/b605345a
The Suzuki-coupling reaction of 2-(dihydroxyboryl)-3,4-dimethyl-2-cyclopenten-1-one (1) and
2-(dihydroxyboryl)-3-methyl-2-cyclopenten-1-one (2) with 2-bromoaniline derivatives affords
cyclopentenone compounds (3–8) from which cyclopentadiene compounds, 4,6-Rꢀ2-
2-(2,5-Me2C5H3)C6H2NH2 (9–11) and 4,6-Rꢀ2-2-(2,3,5-Me3C5H2)C6H2NH2 (12–14) are prepared. After
sulfonation of the –NH2 group with p-TsCl, metallation is carried out by successive addition of
Ti(NMe2)4 and Me2SiCl2 affording o-phenylene-bridged Cp/sulfonamido titanium dichloride
complexes, [4,6-Rꢀ2-2-(2,5-Me2C5H2)C6H2NSO2C6H4CH3)]TiCl2 (Rꢀ = H, 21; Rꢀ = Me, 22; Rꢀ = F, 23)
and [4,6-Rꢀ2-2-(2,3,5-Me3C5H)C6H2NSO2C6H4CH3)]TiCl2 (Rꢀ = H, 24; Rꢀ = Me, 25; Rꢀ = F, 26). The
molecular structures of 24 and [2-(2,5-Me2C5H2)C6H4NSO2C6H4CH3)]Ti(NMe2)2 (27) are determined
by X-ray crystallography. The Cp(centroid)–Ti–N angle in 24 is smaller (100.90◦) than that observed
◦
5
for the CGC (constrained-geometry catalyst), [Me2Si(g -Me4Cp)(NtBu)]TiCl2 (107.6 ) indicating a
more “constrained feature” in 24 than in the CGC. Complex 24 shows the highest activity among the
newly prepared complexes in ethylene/1-octene copolymerization but it is slightly inferior to the CGC
in terms of activity, comonomer-incorporation ability, and molecular weight of the obtained polymers.
devised a novel synthetic route for the ligand system using the
Suzuki-coupling reaction between N-alkyl-2-bromoanilines and 2-
(dihydroxyboryl)-3,4-dimethyl-2-cyclopenten-1-one (1) (eqn (1)).
Introduction
Among the reported homogeneous Ziegler–Natta catalysts,1,2
the most successful one is the silylene-bridged Cp/amido
complex, [Me2Si(g -Me4C5)(NtBu)]TiCl2, which is called CGC
5
(constrained-geometry catalyst).3 Advantages of the CGC over
the conventional bis(cyclopentadienyl)metallocene catalysts are
high a-olefin incorporation, thermal stability, and high molecular
weight in the ethylene/a-olefin copolymerizations, which enable
its use in a commercial process. Since Dow and Exxon reported it
almost simultaneously in the early 1990s,4 various modifications
have been carried out either by replacement of the Me4C5-unit with
other p-donor ligands5 or by replacement of the NtBu-unit with
other amides or phosphides.6 In contrast to the large variations
in the Me4C5- and NtBu-units, modification of the bridge has not
been so abundant and not so successful. Erker reported the prepa-
(1)
1
2
Some complexes are superior to the standard CGC in terms
of activity and 1-hexene incorporation. Herein, we report the
preparation of related o-phenylene-bridged Cp/sulfonamido tita-
nium complexes and their ethylene/1-octene copolymerizations.
The preparation and structure of a related ethylene bridged
Cp/tosylamido titanium dichloride complex were reported with-
out providing any polymerization reactivity.10
=
ration of alkylidene (R R C) or vinylidene (H2C C)-bridged
complexes, but their activities for ethylene polymerization are
significantly lower than that of the standard CGC.7 The ethylene-
5
bridged complex [(g -Me4C5)CH2CH2(NtBu)]TiCl2 was prepared
by Hessen, but it showed much lower a-olefin incorporation.8 Re-
cently, we reported o-phenylene-bridged Me3HC5/amido titanium
complexes and their ethylene/1-hexene copolymerizations.9 We
aDepartment of Molecular Science and Technology, Ajou University, Suwon,
443-749, Korea
Results and discussion
bLG Chem. Ltd./Research Park, 104-1, Munji-dong, Yuseong-gu, Daejon,
305-380, Korea
Synthesis and characterization
cDepartment of Chemistry, Korea University, 208 Seochang, Chochiwon,
Chung-nam, 339-700, Korea. E-mail: bunyeoul@ajou.ac.kr; Fax: +82-31-
219-2394; Tel: +82-31-219-1844
Boronic acid 2 is prepared on a 30 g scale in 94% yield from
2-bromo-3-methyl-2-cyclopenten-1-one using almost the same
conditions and method as applied for the preparation of 1.9
Suzuki-coupling reactions of 1 and 2 with 2-bromoaniline or
† Electronic supplementary information (ESI) available: Experimental
details for compounds 2–20. See DOI: 10.1039/b605345a
4056 | Dalton Trans., 2006, 4056–4062
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Scheme 1 Legend: (i) 2-BrC6H2(Rꢀ)2NH2, Na2CO3, Pd(PPh3)4 (1 mol%); (ii) MeLi/CeCl3, then HCl (2 N); (iii) p-TsCl/pyridine; (iv) Ti(NMe2)4; (v)
Me2SiCl2.
substituted 2-bromoaniline afford the desired coupled compounds
attributed to a high rotation barrier around the N–S bond caused
by the presence of an ortho-methyl group on the phenylene-bridge.
Treatment of the bis(dimethylamido)titanium complexes with
Me2SiCl2 in toluene at room temperature for 1 hour cleanly
gives the desired dichlorotitanium complexes.15 The complexes are
soluble in toluene or benzene but insoluble in pentane or hexane.
Analytically pure complexes are obtained by layer diffusion of
pentane into a benzene solution. Broad single signals are observed
for Cp-CH3 and Cp-H protons, respectively, in the 1H NMR
spectrum of 21, but for 22 and 23 two Cp-CH3 signals and two Cp-
H signals are observed as singlets and as a pair of doublets (J =
3.2 Hz), respectively. These observations may be explained by the
coordination of the oxygen atom to the titanium center (eqn (2)).
1
3–8 in 73–96% yields (Scheme 1). The H NMR, 13C NMR, and
IR spectra are in agreement with the structures.
Addition of 2 equivalents of MeLi to 3–8 and subsequent acidic
work-up does not afford the desired cyclopentadiene compounds,
but the same reaction in the presence of anhydrous CeCl3
furnishes the desired compounds 9–14 in 60–89% yields.11 The
1,5-sigmatropic rearrangement is a facile process in the cyclopen-
tadiene derivatives and it gives rise to a set of isomers for some
substituted cyclopentadiene compounds.12 For compounds 9–14,
the isomer, where two hydrogens are attached on the sp3 carbon, is
substantially more stable than the other isomers and only a set of
signals is observed at room temperature in the 1H and 13C NMR
spectra.13 Compounds 9–11 are obtained contaminated with an
isomer (∼10%) which cannot be removed by chromatography on
silica gel. Observation of a pair of singlet signals at 4.5–5.0 ppm
in the 1H NMR spectra indicates that the minor isomer has
not arisen from the 1,5-sigmatropic rearrangement but from the
exocyclic elimination reaction.14 That kind of undesired isomer
is not observed at all in the case of the trimethylcyclopentadiene
compounds 12–14.
(2)
Complex 21 is under fluxional motion on the NMR time scale
between the two states depicted in eqn (2) and hence broad
single Cp-CH3 and Cp-H signals are observed, respectively. For
complex 22, the state change is prohibited (or very slow) at
room temperature by the presence of the ortho-methyl group
and hence the two methyls and the two hydrogens attached to
the cyclopentadienyl are inequivalent, respectively, on the NMR
time scale. For complex 23, the fluorine atoms on the phenylene
bridge reduce the coordination ability of the nitrogen donor and
consequently the oxygen is bound more strongly to the titanium
not allowing the state change. A set of broad signals is observed
for 24 but, for complexes 25 and 26, two sets of sharp signals
are observed in 2 : 1 and 1 : 1 ratios, respectively, which is also
explained by the coordination of an oxygen atom to the titanium
center. The coordination gives rise to two diastereomers in the case
of the unsymmetric trimethylcyclopentadienyl complexes.
Sulfonamides 15–20 are obtained from 9–14 by treatment with
p-toluenesulfonyl chloride (p-TsCl) in the presence of pyridine
in good yields (80–91% for 15–19, 68% for 20). For compounds
9–14, the Cp-CH2 proton signals are observed at ∼3 ppm as
singlets or narrow multiplets, but for compounds 15–20 the
corresponding signals are observed as AB spin systems, which is
explained by the higher rotation barrier around the C(phenylene)–
C(cyclopentadiene) bond caused by the attachment of the p-
toluenesulfonyl group.
X-Ray crystallographic studies
Reaction of 15–20 with Ti(NMe2)4 in toluene at 60 ◦C for
12 hours affords the desired chelated bis(dimethylamido)titanium
complexes. The Cp-H and the NCH3 signals are very broad in the
case of the complexes derived from 16 and 19. The broadening is
Single crystals of the intermediate bis(dimethylamido)titanium
complex [C6H4(Me2H2C5)(NTs)]Ti(NMe2)2 (27) suitable for X-
ray crystallography are obtained by layer diffusion of pentane
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◦
˚
7.8 ), the measured Ti–O separation (3.022 A) is too large to be a
chemical bond between these two atoms.
Layer diffusion of pentane into a C6D6 solution of 23 in a NMR
cell affords yellow single crystals along with powdery precipitates.
An X-ray crystallographic study of the yellow single crystal
revealed the structure of an unexpected dinuclear l-oxo complex
28 (Fig. 2). A similar dinuclear l-oxo zirconium complex was ob-
served by us when crystal growing was conducted for (Me2H2C5–
C(Ph)H–NtBu)ZrCl2 by the same method.17 Formation of the
water-absorbed complex even in thoroughly dried solvents implies
that the complex is highly reactive towards water.
Fig. 1 Thermal ellipsoid plot (30% probability level) of 27. Selected
bond distances (A) and angles (◦): Ti–N(1), 2.1095(15); Ti–N(2),
˚
1.9200(17); Ti–N(3), 1.8935(17); Ti–C(7), 2.3355(19); Ti–C(8), 2.400(2);
Ti–C(9), 2.398(2); Ti–C(10), 2.365(2); Ti–C(11), 2.369(2); S–N(1),
1.6249(15); Cp(centroid)–Ti, 2.046; O(1)–Ti, 3.022; S–O(1), 1.4381(16);
S–O(2), 1.4396(15); Cp(centroid)–Ti–N(1), 102.95; N(3)–Ti–N(2),
104.12(8); C(2)–N(1)–S, 119.88(12); C(2)–N(1)–Ti, 122.93(12);
S–N(1)–Ti, 117.19(8); C(2)–C(1)–C(7), 116.09(17); C(1)–C(2)–N(1),
114.42(16); Cp(centroid)–C(7)–C(1), 172.79; C(7)–Cp(centroid)–Ti,
88.15; Ti–N(1)–S–C(14), 105.5; Ti–N(1)–S–O(1), 7.8.
into a benzene solution. Fig. 1 shows the structure with the
selected bond distances and angles. The Cp(centroid)–Ti–N angle
has been used as a qualitative measure for the “constrained
geometry”. The smaller the Cp(centroid)–Ti–N angle is, the
more pronounced the “constrained geometry” features should
be. The Cp(centroid)–Ti–N angle (10◦2.95◦) is smaller than those
observed for the standard CGC (107.6 )16 and for the o-phenylene-
Fig. 2 Thermal ellipsoid plot (30% probability level) of 28.
When crystal growing is conducted with 24 by the same method
applied for 23, red single crystals are obtained without formation
of any fluffy precipitates. An X-ray crystallographic study revealed
the structure of the desired chelated titanium dichloride complex.
Two independent molecules are present in the asymmetric unit
cell. Fig. 3 shows its structure with the selected bond distances
and angles measured for one molecule in the asymmetric unit
cell. The metrical parameters measured for the other molecule
are almost the same. The Cp(centroid)–Ti–N angle (100.91◦) is
contracted from that observed for 27 (102.95◦). The angle is
significantly small when compared with those observed for the
standard CGC (107.6◦) and the o-phenylene-bridged complex [2-
5
bridged complex [2-(g -2,3,5-Me3C5H)C6H3NC6H11]TiCl2 (104.6
and 104.8◦)9 indicating a more “constrained feature” in the o-
phenylene-bridged Cp/sulfonamido complex. The ipso-carbon
on the phenylene bridge does not acutely deviate from the cy-
clopentadienyl plane (Cp(centroid)–C(bridgehead)–C(Ph) angle,
172.79◦) which is in contrast with the observation of acute
deviation of the Si atom from the cyclopentadienyl plane for
the silylene-bridged complexes (Cp(centroid)–C(bridgehead◦)–Si
angles for C5R4SiMe2(N-t-Bu) titanium complexes, 150–154 ).17
The Cp(centroid)–Ti vector does not deviate from the normal
direction and is situated almost perpendicularly to the cyclopen-
tadienyl plane (Ti–Cp(centroid)–C(bridgehead) angle, 88.15◦).
◦
5
(g -2,3,5-Me3C5H)–C6H3N–C6H11]TiCl2 (104.6 and 104.8 ). Even
though the “constrained geometry” feature is large in this system,
the elements constituting the chlelation are not situated in a
severely strained position. That is, the ipso-carbon (C(9)) on
the phenylene bridge is situated on the cyclopentadienyl plane
((Cp(centroid)–C(1)–C(9) angle, 174.62◦) and the titanium atom
is bonded perpendicularly to the cyclopentadienyl ligand (C(1)–
Cp(centroid)–Ti(1), 89.24◦) as is observed for 27. The Ti–N dis-
˚
The Ti–NTs bond distance (2.1095(15) A) is substantially longer
˚
than those observed for the standard CGC (1.907(4) A) and
5
˚
[2-(g -2,3,5-Me3C5H)C6H3NC6H11]TiCl2 (1.902 A) indicating a
˚
tance (2.005(5) A) is reduced from that observed for 27 (2.1095(15)
weaker Ti–N bond strength for the sulfonamide complex. The
sulfonamide nitrogen atom is perfectly trigonal and the sum of
the bond angles around the nitrogen atom amounts to 360.0◦.
The cyclopentadienyl plane is situated almost perpendicularly to
the phenylene plane (angle between the plane, 79.68(8)◦) and the
titanium atom is situated on the phenylene plane (distance between
˚
˚
A) but still longer than those observed for the CGC (1.907(4) A)
5
˚
and for [2-(g -2,3,5-Me3C5H)C6H3NC6H11]TiCl2 (1.902 A). The
nitrogen atom is perfectly trigonal (sum of the bond angles around
the nitrogen atom, 360.0◦). An oxygen atom (O(1)) is situated
˚
close to the titanium and the Ti–O distance is 2.414 A, which is
˚
˚
the Ti and the phenylene plane, 0.194(4) A). Even though the –
substantially shorter than that observed for 27 (3.022 A). This
1
SO2C7H7 fragment is situated allowing for one oxygen (O(1)) to
be close to the titanium atom (dihedral angle of Ti–N(1)–S–O(1),
short distance along with the H NMR signal pattern described
above indicates chemical bonding between these two atoms. An
4058 | Dalton Trans., 2006, 4056–4062
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of Al(iBu)3. The Al(iBu)3 is added both as a scavenger and as an
alkylating agent. The polymerization conditions and the results
are summarized in Table 1. The activity is very sensitive not
only to the substituents on the phenylene bridge but also to the
number of methyl substituents on the cyclopentadienyl ligand.
Introduction of dimethyl or difluoro groups on the phenylene-
bridge significantly reduces the activity (entries, 2–3 and 5–6). By
placing one more methyl group on the cyclopentadienyl ligand,
the activity increases more than two times (entries 1 and 4). The
activity of 24 (130 × 106 g molTi h−1) nearly reaches that of the
−1
CGC (160 × 106 g molTi h−1).
−1
The 1-octene content in the copolymer is usually calculated by
the analysis of the 13C NMR spectrum of the copolymer18 but, in
the case of the copolymers containing significant amounts of a-
olefin, it can be measured more easily from the 1H NMR spectrum.
1
In the H NMR spectrum (Fig. 4), the methyl signal (0.93–1.02
ppm) is suitably isolated from the methine and methylene signals
(1.30–1.50 ppm) and the 1-octene content can be calculated from
the integration values of the two signals. Usually, higher incor-
poration of a-olefin can be expected for the complex exhibiting
the smaller Cp(centroid)–Ti–N angle. Complex 24 has a smaller
Cp(centroid)–Ti–N angle than the CGC, but the 1-octene content
(15 mol%) of the copolymer obtained with 24 is less than that of
the copolymer obtained with the standard CGC (19 mol%). This
discrepancy might be due to the additional coordination of the
oxygen atom.
Fig. 3 Thermal ellipsoid ◦plot (30% probability level) of 24. Selected bond
˚
distances (A) and angles ( ): Ti–N, 2.005(5); Ti–Cl(1), 2.272(2); Ti–Cl(2),
2.274(2); Ti–C(1), 2.356(6); Ti–C(2), 2.401(7), Ti–C(3), 2.403(7); Ti–C(4),
2.364(7); Ti–C(5), 2.344(6); Cp(centroid)–Ti(1), 2.046; S–N, 1.606(5);
S–O(1), 1.462(5); S–O(2), 1.426(5); O(1)–Ti(1), 2.416; Cp(centroid)–Ti–N,
100.91; Cl(1)–Ti–Cl(2), 104.98(8); C(10)–N–S, 123.7(4); C(10)–N–Ti,
130.0(4); S–N–Ti, 106.3(3); C(10)–C(9)–C(1), 112.7(5); C(9)–C(10)–N,
112.3(5); Cp(centroid)–C(1)–C(9), 174.62; C(1)–Cp(centroid)–Ti, 89.24;
Ti–N–S–C(15), 110.8; Ti–N–S–O(1), 3.1.
oxygen atom is also situated close to the titanium center in
5
case of the related complex [g -CpCH2CH2NTs]TiCl2, which was
interpreted as a bonding interaction between these two atoms.10 By
the coordination of the oxygen atom, the S–O(1) distance (1.462(5)
˚
˚
A) is elongated a little (the other S–O distance, 1.426(5) A; the S–
˚
O distances in 27, 1.4381(16) and 1.4396(15) A) and the Ti–N–S
angle is contracted to 106.3(3)◦ from the normal angle of 120◦. The
Ti–N–S angle observed for the oxygen-uncoordinated complex 27
is 117.19(8)◦.
Polymerization studies
The prepared complexes were tested for ethylene/1-octene copoly-
merization after activation with [Ph3C][B(C6F5)4] in the presence
Fig. 4 The 1H NMR spectrum of the ethylene/1-octene copolymer.
Table 1 Ethylene/1-octene copolymerization resultsa
Entry
Catalyst b
Yield/g
Ac
Tm/◦C
[Oct]
14
MId
Mw
Mw/Mn
1
2
3
4
5
6
7
21
43
5.3
Trace
110
3.4
5.1
130
51
6.4
86.6
104.9
146
13.1
28 000
71 000
2.0
6.1
22
23
24
130
4.1
6.1
160
92.8
86.0
90.7
89.4
15
14
24
19
26
49 000
85 000
191 000
56 000
3.0
3.9
6.0
2.8
25
2.7
0.23
20
26
CGC
a Polymerization conditions: 1000 mL toluene solution of 1-octene (0.8 M), 5 lmol complex, 15 lmol of [Ph3C][B(C6F5)4], 0.125 mmol of Al(iBu)3, 13 bar
ethylene, 10 minutes, 90 ◦C. b Activity in units of 106 g molTi h−1
.
c 1-Octene content in the copolymer measured by 1H NMR. d Melt index which is the
−1
melt flow rate (g per 10 min) at 190 ◦C and using a load of 2160 g.
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Attachment of one more methyl group to the cyclopentadienyl
ligand leads to a significant increase in the molecular weight
(entries 1 and 4), but the molecular weight of the polymer obtained
with 24 is still slightly smaller than that of the polymer obtained
with the CGC (Mw, 49 000 and 56 000 for 24 and the CGC,
respectively). The melt flow rate (MI) of the polymer is strongly
related to the molecular weight and the MI data are in good accord
with the molecular weights measured using GPC.
NMe2), 5.75 (s, 2H, Cp-H), 6.74 (d, J = 6.8 Hz, 2H, Ts-H), 6.83 (t,
J = 6.8 Hz, 1H, C6H4-CH), 6.96 (d, J = 6.8 Hz, 1H, C6H4-CH),
7.13 (t, J = 6.8 Hz, 1H, C6H4-CH), 7.78 (d, J = 6.8 Hz, 2H, Ts-H),
8.11 (d, J = 6.8 Hz, 1H, C6H4-CH) ppm. To a flask containing the
resulting bis(dimethylamido)titanium complex in toluene (10 mL)
was added Me2SiCl2 (0.570 g, 4.42 mmol). After the solution was
stirred for 1 hour at room temperature, all volatiles were removed
under vacuum to give a red residue which was triturated in pentane
(0.464 g, overall 63%). 1H NMR (C6D6): d 1.72 (s, 3H, CH3), 1.79 (s,
6H, CH3), 6.65 (s, 2H, Cp-H), 6.65 (d, J = 7.6 Hz, 2H, Ts-H), 6.81
(d, J = 7.2 Hz, 1H, C6H4-CH), 6.86 (t, J = 7.2 Hz, 1H, C6H4-CH),
6.99 (t, J = 7.2 Hz, 1H, C6H4-CH), 7.09 (d, J = 7.2 Hz, 1H, C6H4-
Conclusion
o-Phenylene-bridged Me2H2C5 (or Me3HC5)/sulfonamide
ligands are prepared. The Suzuki-coupling reaction of 2-
1
CH), 8.15 (d, J = 7.6 Hz, 2H, Ts-H) ppm. 13C{ H} NMR (C6D6): d
(dihydroxyboryl)-3,4-dimethyl-2-cyclopenten-1-one
(1)
and
15.07, 21.44, 114.52, 124.0 (broad), 124.85, 126.23, 128.11, 128.39,
128.88, 129.76, 130.09, 135.30, 143.93, 145.28, 155.01 ppm. Anal.
Calc. (C20H19Cl2NO2STi): C, 52.65; H, 4.20; N, 3.07%. Found: C,
52.71; H, 4.37; N, 2.93%.
2-(dihydroxyboryl)-3-methyl-2-cyclopenten-1-one (2) with 2-
bromoaniline derivatives is the key step in the preparation. The
chelated metal complexes are obtained by successive addition
1
of Ti(NMe2)4 and Me2SiCl2 to the ligands. The H NMR and
Complex 22. The compound was synthesized from 16 using
the same conditions and procedures as for 21. Overall yield for
the dichloride complex from 16 was 68%. The NMR data for
the intermediate bis(dimethylamido)titanium complex: 1H NMR
(C6D6): d 1.95 (s, 3H, CH3), 2.05 (s, 9H, CH3), 2.17 (s, 3H, CH3),
3.32 (br s, 12H, NMe2), 5.94 (s, 2H, Cp-CH), 6.76 (s, 1H, C6H2-
CH), 6.86 (d, J = 8.0 Hz, 2H, Ts-H), 6.95 (s, 1H, C6H2-CH),
8.25 (d, J = 8.0 Hz, 2H, Ts-H) ppm. The analytical data for
X-ray crystallographic studies show that both the nitrogen
and the oxygen atoms on the sulfonamide coordinate to the
titanium for the dichlorotitanium complexes while only the
nitrogen atom coordinates for the bis(dimethylamido)titanium
complexes. The Cp(centroid)–Ti–N angles measured on the
X-ray structures of the o-phenylene-bridged Cp/sulfonamide
complexes are substantially smaller than those observed for
5
the CGC and for [Me2Si(g -Me4C5)(NtBu)]TiCl2, indicating a
1
the dichlorotitanium complex: H NMR (C6D6): d 1.81 (s, 3H,
more “constrained feature” in the sulfonamide complex, but less
1-octene is incorporated by the sulfonamide complex during
ethylene/1-octene copolymerization, which might be attributed
to the additional oxygen-coordination. The activity is highly
sensitive not only to the substituents on the phenylene bridge but
also to the number of methyl substituents on the cyclopentadienyl
ligand. The highest activity is observed with the unsubstituted
o-phenylene-bridged Me3HC5/sulfonamide complex (24) and it
nearly reaches that of the CGC.
CH3), 1.88 (s, 3H, CH3), 1.92 (s, 3H, CH3), 2.08 (s, 3H, CH3),
2.21 (s, 3H, CH3), 6.54 (d, J = 3.2 Hz, 1H, Cp–CH), 6.55–6.56
(m, 1H, C6H2-CH), 6.61–6.63 (m, 1H, C6H2-CH), 6.64 (d, J =
8.0 Hz, 2H, Ts-H), 6.68 (d, J = 3.2 Hz, 1H, Cp-CH), 8.10 (d, J =
1
8.0 Hz, 2H, Ts-H) ppm. 13C{ H} NMR (C6D6): d 14.60, 16.84,
20.76, 20.98, 21.41, 123.35, 125.03, 126.90, 127.77, 128.56, 129.46,
129.93, 133.20, 134.90, 137.12, 137.91, 140.36, 144.63, 145.17,
148.77 ppm. Anal. Calc. (C22H23Cl2NO2STi): C, 54.56; H, 4.79;
N, 2.89%. Found: C, 54.62; H, 4.75; N, 2.93%.
Experimental
Complex 23. The compound was synthesized from 17 using
the same conditions and procedures as for 21. Overall yield for
the dichloride complex from 17 was 62%. The NMR data for
the intermediate bis(dimethylamido)titanium complex: 1H NMR
(C6D6): d 1.89 (s, 6H, CH3), 1.93 (s, 3H, CH3), 3.28 (s, 12H,
NMe2), 5.85 (s, 2H, Cp-CH), 6.46–6.52 (m, 1H, C6H2F2-CH),
6.63–6.66 (m, 1H, C6H2F2-CH), 6.86 (d, J = 8.0 Hz, 2H, Ts-H),
8.24 (d, J = 8.0 Hz, 2H, Ts-H) ppm. The analytical data for the
dichlorotitanium complex: 1H NMR (C6D6): d 1.65 (s, 3H, CH3),
General remarks
All manipulations were performed under an inert atmosphere
using standard glovebox and Schlenk techniques. Toluene, pen-
tane, THF, and C6D6 were distilled from sodium benzophenone.
NMR spectra were recorded on a Varian Mercury plus 400.
Elemental analyses were carried out at the Inter-University
Center Natural Science Facilities, Seoul National University.
3
◦
1.77 (s, 3H, CH3), 1.83 (s, 3H, CH3), 6.12 (ddd, JHF = 7.2 Hz,
Gel permeation chromatograms (GPC) were obtained at 140 C
4JHH = 2.4 Hz, 5JHF = 1.2 Hz, 1H, C6H2F2-H), 6.22 (t, ddd, 3JHF
=
in trichlorobenzene using Waters Model 150 ◦C + GPC and
the data were analyzed using a polystyrene analyzing curve.
Differential scanning calorimetry (DSC) was performed on a
Thermal Analysis 3100. Details of synthetic procedures and
characterizations of 2–20 are available as ESI.†
3
4
14.4 Hz, JHF = 8.8 Hz, JHF = 2.4 Hz, 1H, C6H2F2-H), 6.53 (d,
J = 3.2 Hz, 1H, Cp-CH), 6.64 (d, J = 8.4 Hz, 2H, Ts-H), 6.72 (d,
J = 3.2 Hz, 1H, Cp-CH), 8.19 (d, J = 8.4 Hz, 2H, Ts-H), ppm.
19F NMR (C6D6): d −106.14 (d, J = 6.8 Hz), −114.33 (d, J = 6.8
Hz) ppm. Anal. Calc. (C20H17Cl2F2NO2STi): C, 48.81; H, 3.48; N,
2.85%. Found: C, 48.75; H, 3.52; N, 2.69%.
Syntheses
Complex 21. Compound 15 (0.500 g, 1.473 mmol), Ti(NMe2)4
(0.330 g, 1.473 mmol), and toluene (10 mL) were added to a
Schlenk flask. The solution was stirred for 12 hours at 60 ◦C. Re-
moval of solvent and extraction with pentane gave a red solid. 1H
NMR (C6D6): d 1.66 (s, 6H, CH3), 1.87 (s, 3H, CH3), 3.28 (s, 12H,
Complex 24. The compound was synthesized from 18 using
the same conditions and procedures as for 21. Overall yield for
the dichloride complex from 18 was 70%. The NMR data for
the intermediate bis(dimethylamido)titanium complex: 1H NMR
(C6D6): d 1.64 (s, 3H, CH3), 1.70 (s, 3H, CH3), 1.83 (s, 3H, CH3),
4060 | Dalton Trans., 2006, 4056–4062
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1.89 (s, 3H, CH3), 3.08 (s, 6H, NMe2), 3.51 (s, 6H, NMe2), 5.95
(s, 1H, Cp-CH), 6.76 (d, J = 8.0 Hz, 2H, Ts-H), 6.82 (t, J =
7.2 Hz, 1H, C6H4-CH), 6.98 (d, J = 7.2 Hz, 1H, C6H4-CH), 7.10
(t, J = 7.2 Hz, 1H, C6H4-CH), 7.76 (d, J = 8.0 Hz, 2H, Ts-H),
8.06 (d, J = 7.2 Hz, 1H, C6H4-CH) ppm. The analytical data for
the dichlorotitanium complex: 1H NMR (C6D6): d 1.66 (br s, 3H,
CH3), 1.79 (br s, 6H, CH3), 2.26 (br s, 3H, CH3), 6.48 (s, 1H, Cp-
CH), 6.66 (d, J = 8.0 Hz, 2H, Ts-H), 6.80–6.92 (m, 2H, C6H4-CH),
7.01 (br t, J = 7.2 Hz, 1H, C6H4-CH), 7.12 (d, J = 7.2 Hz, 1H,
139.34, 139.54, 144.49, 144.53, 146.19, 146.27, 148.83 ppm. Anal.
Calc. (C23H25Cl2NO2STi): C, 55.44; H, 5.06; N, 2.81%. Found: C,
55.61; H, 5.10; N, 2.93%.
Complex 26. The compound was synthesized from 20 using
the same conditions and procedures as for 21. Overall yield for
the dichloride complex from 20 was 69%. The NMR data for
the intermediate bis(dimethylamido)titanium complex: 1H NMR
(C6D6): d 1.70 (s, 3H, CH3), 1.93 (s, 3H, CH3), 2.00 (s, 3H, CH3),
2.04 (s, 3H, CH3), 3.12 (s, 6H, NMe2), 3.44 (s, 6H, NMe2), 5.88 (s,
1H, Cp-CH), 6.49–6.54 (m, 1H, C6H2F2-CH), 6.65–6.68 (m, 1H,
C6H2F2-CH), 6.86 (d, J = 8.0 Hz, 2H, Ts-H), 8.22 (d, J = 8.0 Hz,
2H, Ts-H) ppm. The analytical data for the dichlorotitanium
complex (1 : 1 mixture): 1H NMR (C6D6): d 1.61 (s, 1.5H, CH3),
1.72 (s, 1.5H, CH3), 1.81 (s, 1.5H, CH3), 1.82 (s, 1.5H, CH3), 1.83
(s, 1.5H, CH3), 1.90 (s, 1.5H, CH3), 2.28 (s, 3H, CH3), 6.26–6.32
(m, 2H, C6H2F2), 6.46 (s, 0.5H, Cp-CH), 6.63 (s, 0.5H, Cp-CH),
6.70 (d, J = 8.0 Hz, 2H, Ts-H), 8.17–8.20 (m, 2H, Ts-H) ppm.
19F NMR (C6D6): d −107.47 (d, J = 6.8 Hz), −115.56 (d, J = 6.8
Hz) ppm. Anal. Calc. (C21H19Cl2F2NO2STi): C, 49.83; H, 3.78; N,
2.77%. Found: C, 50.02; H, 3.85; N, 2.68%.
1
C6H4-CH), 8.16 (d, J = 8.0 Hz, 2H, Ts-H) ppm. 13C{ H} NMR
(C6D6): d 12.80, 15.20, 15.44, 21.41, 114.60, 124.57, 124.62, 125.63,
126.84, 128.41, 128.50, 128.92, 129.27, 129.71, 130.01, 135.61,
135.69, 145.03, 155.27 ppm. Anal. Calc. (C21H21Cl2NO2STi): C,
53.64; H, 4.50; N, 2.98%. Found: C, 53.57; H, 4.62; N, 3.09%.
Complex 25. The compound was synthesized from 19 using
the same conditions and procedures as for 21. Overall yield for
the dichloride complex from 19 was 78%. The NMR data for
the intermediate bis(dimethylamido)titanium complex: 1H NMR
(C6D6): d 1.88 (s, 3H, CH3), 1.95 (s, 3H, CH3), 2.06 (s, 3H, CH3),
2.14 (s, 6H, CH3), 2.19 (s, 3H, CH3), 3.23 (s, 6H, NMe2), 3.43 (s, 6H,
NMe2), 5.93 (s, 1H, Cp-CH), 6.77 (s, 1H, C6H2-CH), 6.85 (d, J =
5.6 Hz, 2H, Ts-H), 6.96 (s, 1H, C6H2-CH), 8.23 (d, J = 5.6 Hz, 2H,
Ts-H) ppm. The analytical data for the dichlorotitanium complex
Polymerization
1
(2 : 1 mixture): H NMR (C6D6): d 1.80 (s, 3H, CH3), 1.84 (s,
To a 2.0 L Bu¨ch reactor were added 1.0 L of a toluene solution of
1-octene (0.80 M) and (iBu)3Al (0.5 mmol). After the solution
was heated to 90 ◦C, it was saturated with ethylene gas (13
bar). An activated catalyst, which was prepared by mixing
the complex (5.0 lmol Ti), [CPh3]+[B(C6F5)4]− (15 lmol) and
(iBu)3Al (0.125 mmol) for 2 minutes, was added to the reactor
by pressurizing the catalyst-feed tank with N2. After the ethylene
(13 psig) had been fed continuously for 10 minutes, the reaction
mixture was drained into a flask containing ethanol to give white
precipitates which were collected by filtration and dried under
1H, CH3), 1.90 (s, 2H, CH3), 1.92 (s, 2H, CH3), 1.95 (s, 1H,
CH3), 2.11 (s, 1H, CH3), 2.13 (s, 2H, CH3), 2.15 (s, 2H, CH3),
2.28 (s, 1H, CH3), 2.29 (s, 1H, CH3), 2.40 (s, 2H, CH3), 6.38
(s, 0.33H, Cp-CH), 6.51 (s, 0.67H, Cp-CH), 6.61–6.64 (m, 2H,
Ts-H), 6.64 (s, 2H, C6H2-CH), 8.08–8.12 (m, 2H, Ts-H) ppm.
1
13C{ H} NMR(C6D6): d 12.70, 14.42, 14.74, 15.80, 16.32, 17.12,
20.84, 20.86, 21.40, 124.94, 126.01, 126.89, 126.94, 127.77, 128.52,
128.64, 129.07, 129.33, 129.87, 129.91, 130.04, 130.30, 132.99,
133.12, 134.74, 134.83, 135.65, 135.70, 135.82, 137.66, 138.08,
Table 2 Crystallographic parameters of 27, 28 and 24a
27
28
24
Formula
M
Color
C24H31N3O2STi
473.48
Red
C40H36Cl4F4N2O5S2Ti2
1002.43
Yellow
C21H20Cl2NO2STi
470.25
Red
Size/mm
0.5 × 0.1 × 0.03
31.743(3)
11.5195(11)
13.1968(12)
90
98.297(2)
90
4775.1(8)
Monclinic
C2/c
1.317
8
0.471
24251
5993
288
0.0376
0.0953
1.053
0.1 × 0.1 × 0.06
0.2 × 0.08 × 0.01
11.194(4)
9.734(3)
19.677(7)
90
˚
a/A
8.927(5)
˚
b/A
13.917(8)
˚
c/A
18.663(10)
101.172(12)
97.017(13)
102.053(13)
2192(2)
a/◦
b/◦
c /◦
90
90
3
˚
V/A
2144.2(13)
Orthorhombic
P212121
1.457
Crystal system
Space group
D(calc)/g cm−1
Z
Triclinic
¯
P1
1.519
2
4
l/mm−1
0.765
30361
10937
539
0.0924
0.1957
0.856
0.762
21958
5347
258
0.0639
0.1429
1.050
No. of data collected
No. of unique data
No. of variables
R
Rw
Goodness of fit
ꢀ
ꢀ
ꢀ
ꢀ
2
a Data collected at 293(2) K, R(F) = ||Fo| − |Fc||/ |Fo| with Fo > 2.0r(I), Rw = [ [w(Fo − Fc2)2]/ [w(Fo)2]2]1/2 with Fo > 2.0r(I).
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vacuum. The copolymer (10 mg) was dissolved in C6D6 in order
to record the 1H NMR spectra at 78 ◦C.
M. Kraft, M. O. Kristen and D. Leusser, J. Am. Chem. Soc., 2005, 127,
3282; H. Li, L. Li, D. J. Schwartz, M. V. Metz, T. J. Marks, L. Liable-
Sands and A. L. Rheingold, J. Am. Chem. Soc., 2005, 127, 14756; W.
Wang, M. Fujiki and K. Nomura, J. Am. Chem. Soc., 2005, 127, 4582;
M. van Meurs, G. J. P. Britovsek, V. C. Gibson and S. A. Cohen, J. Am.
Chem. Soc., 2005, 127, 9913.
3 A. L. McKnight and R. M. Waymouth, Chem. Rev., 1998, 98, 2587;
V. C. Gibson and S. K. Spitzmesser, Chem. Rev., 2003, 103, 283.
4 J. C. Stevens, F. J. Timmers, D. R. Wilson, G. F. Schmidt, P. N. Nickias,
R. K. Rosen, G. W. Knight and S. Y. Lai (Dow Chemical Company),
Eur. Pat. Appl., EP 416815-A2, 1991; J. M. Canich (Exxon Chemical
Company), Eur. Pat. Appl., EP 420436-A1, 1991.
5 L. J. Irwin and S. A. Miller, J. Am. Chem. Soc., 2005, 127, 9972; C.
Grandini, I. Camurati, S. Guidotti, N. Mascellani, L. Resconi, I. E.
Nifant’ev, I. A. Kashulin, P. V. Ivchenko, P. Mercandelli and A. Sironi,
Organometallics, 2004, 23, 344; C. De Rosa, F. Auriemma, O. Ruiz de
Ballesteros, L. Resconi, A. Fait, E. Ciaccia and I. Camurati, J. Am.
Chem. Soc., 2003, 125, 10913; J. Klosin, W. J. Jr. Kruper, P. N. Nickias,
G. R. Roof, P. De Waele and K. A. Abboud, Organometallics, 2001, 20,
2663.
X-Ray crystallography
Crystals of 24, 27, and 28 were mounted in thin-walled glass
capillaries and sealed under argon. The data sets were collected
on a Bruker Smart CCD detector single diffractometer. Mo-Ka
˚
radiation (k = 0.7107 A) was used for all structures. The structures
were solved by direct methods using the SHELX-96 program and
least-squares refinement using the SHELXL-Plus (5.1) software
package. All non-hydrogen atoms were refined anisotropically. All
hydrogen atoms were included in calculated positions. The crystal
data and refinement results are summarized in Table 2.
CCDC reference numbers 604506–604508.
For crystallographic data in CIF or other electronic format see
DOI: 10.1039/b605345a
6 G. Altenhoff, S. Bredeau, G. Erker, G. Kehr, O. Kataeva and R.
Frohlich, Organometallics, 2002, 21, 4084.
7 K. Kunz, G. Erker, S. Doring, R. Frohlich and G. Kehr, J. Am. Chem.
Soc., 2001, 123, 6181; C. Wang, G. Erker, G. Kehr, K. Wedeking and
R. Frohlich, Organometallics, 2005, 24, 4760.
Acknowledgements
The authors are grateful for financial support from the Ministry
of Commerce, Industry and Energy.
8 D. van Leusen, D. J. Beetstra, B. Hessen and J. H. Teuben,
Organometallics, 2000, 19, 4084 and references therein.
9 D. J. Cho, C. J. Wu, S. S. W.-S. Han, S. O. Kang and B. Y. Lee,
Organometallics, 2006, 25, 2133.
10 C. Lensink, J. Organomet. Chem., 1998, 553, 387.
References
11 For CeCl3-mediated reaction, see: A. Krasovskiy, F. Kopp and P.
Knochel, Angew. Chem., Int. Ed., 2006, 45, 497 and references therein.
12 P. Jutzi, Chem. Rev., 1986, 86, 983.
1 Review: H. H. Brintzinger, D. Fischer, R. Mu¨lhaupt, B. Rieger and
R. M. Waymouth, Angew. Chem., Int. Ed. Engl., 1995, 34, 1143; G. J. P.
Britovsek, V. C. Gibson and D. F. Wass, Angew. Chem., Int. Ed., 1999,
38, 429; H. G. Alt and A. Ko¨pple, Chem. Rev., 2000, 100, 1205; G. W.
Coates, Chem. Rev., 2000, 100, 1223; L. Resconi, L. Cavallo, A. Fait
and F. Piemontesi, Chem. Rev., 2000, 100, 1253; E. Y.-X. Chen and T. J.
Marks, Chem. Rev., 2000, 100, 1391; H. G. Alt, Dalton Trans., 2005,
3271.
2 Recent progress: K. A. O. Starzewski, B. S. Xin, N. Steinhauser, J.
Schweer and J. Benet-Buchholz, Angew. Chem., Int. Ed., 2006, 45, 1799;
M. B. Harney, R. J. Keaton, J. C. Fettinger and L. R. Sita, J. Am. Chem.
Soc., 2006, 128, 3420; X. Li, J. Baldamus and Z. Hou, Angew. Chem.,
Int. Ed., 2005, 44, 962; A. P. Dove, X. Xie and R. M. Waymouth, Chem.
Commun., 2005, 2152; X. Zhang, A. B. Sieval, J. C. Hummelena and
B. Hessen, Chem. Commun., 2005, 1616; H. Braunschweig, M. Gross,
13 E. S. Cho, U. G. Joung, B. Y. Lee, H. Lee, Y.-W. Park, C. H. Lee and
D. M. Shin, Organometallics, 2004, 23, 4693; D. J. Joe, B. Y. Lee and
D. M. Shin, Bull. Korean Chem. Soc., 2005, 25, 233.
14 B. Y. Lee, J. W. Han, Y. K. Chung and S. W. Lee, J. Organomet. Chem.,
1999, 587, 181.
15 B. Y. Lee, J. W. Han, I. S. Lee and Y. K. Chung, J. Organomet. Chem.,
2001, 627, 233.
16 D. W. Carpenetti, L. Kloppenburg, J. T. Kupec and J. L. Petersen,
Organometallics, 1996, 15, 1572.
17 T. H. Kim, Y. C. Won, B. Y. Lee, D. M. Shin and Y. K. Chung,
Eur. J. Inorg. Chem., 2004, 1522.
18 W. Liu, P. L. Rinaldi, L. H. McIntosh and R. P. Quirk, Macromolecules,
2001, 34, 4757.
4062 | Dalton Trans., 2006, 4056–4062
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©