1,1-Olefin-bridged bis-(2-indenyl) metallocenes of titanium and zirconium

Article abstract of DOI:10.1039/c4dt01583e

Tetrasubstituted alkenes bearing geminal 2-indenyl substituents-9-[bis(1H- inden-2-yl)methylidene]-9H-fluorene (6), 2,2′-(2,2-diphenylethene-1,1- diyl)-bis(1H-indene) (7), and 2,2′-(2-propylpent-1-ene-1,1-diyl)-bis(1H- indene) (8) have been synthesized and metallated to form a new class of ansa titanium and zirconium metallocene complexes containing a single sp ²-hybridized carbon bridge. The synthesis of the tetramethylated bis-indenyl Zr-analog is described. In addition, the 1,1-bis-indenyl ethylene is prepared and the Zr complex is modified by olefin metathesis. X-ray structure analyses reveal strained η⁵ sandwich complexes with highly open metal centers. These complexes have proven active in the polymerization of ethylene and its copolymerization with 1-hexene.

Full text of DOI:10.1039/c4dt01583e

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1,1-Olefin-bridged bis-(2-indenyl) metallocenes
of titanium and zirconium†
Cite this: Dalton Trans., 2014, 43,
13219
a
b
a
a
Jason G. M. Morton,‡ Haif Al-Shammari, Yunshan Sun, Jiangtao Zhu and
a
Douglas W. Stephan*
Tetrasubstituted alkenes bearing geminal 2-indenyl substituents – 9-[bis(1H-inden-2-yl)methylidene]-
9
H-fluorene (6), 2,2’-(2,2-diphenylethene-1,1-diyl)-bis(1H-indene) (7), and 2,2’-(2-propylpent-1-ene-
1
,1-diyl)-bis(1H-indene) (8) have been synthesized and metallated to form a new class of ansa titanium
2
and zirconium metallocene complexes containing a single sp -hybridized carbon bridge. The synthesis of
the tetramethylated bis-indenyl Zr-analog is described. In addition, the 1,1-bis-indenyl ethylene is prepared
Received 29th May 2014,
Accepted 14th July 2014
5
and the Zr complex is modified by olefin metathesis. X-ray structure analyses reveal strained η sandwich
DOI: 10.1039/c4dt01583e
complexes with highly open metal centers. These complexes have proven active in the polymerization of
www.rsc.org/dalton
ethylene and its copolymerization with 1-hexene.
Introduction
While heterogeneous Ziegler–Natta titanium and Phillips chro-
mium catalyst systems are currently utilized for the bulk of
1
industrial linear polyethylene production, great attention con-
tinues to be directed towards the synthesis and evaluation of
homogeneous transition-metal catalysts. Such soluble, single-
site species are infinitely variable in their ligand scaffolding,
allowing for the designed perturbation of the metal’s elec- Fig. 1 Metallocene with an sp -hybridized bridging carbon.
tronic and structural environment. Soluble catalysts are of par-
2
ticular interest to complement existing heterogeneous high-
and low-density polyethylene (HDPE and LDPE) processes
through the production of linear low-density polyethylene
To our knowledge, there have been no reports of ansa-metallo-
cene bridges containing a single, unsaturated carbon in the
backbone (Fig. 1). We were drawn to such systems in the belief
(LLDPE), where longer α-olefins such as 1-butene, 1-hexene,
2
that an sp -hybridized carbon would enlarge the angle between
and 1-octene are incorporated into the polyethylene chain.
the indenyl substituents, and thus provide a more open metallo-
cene than that seen for the corresponding species containing
Group 4 ansa-metallocenes with a single atom bridge con-
2
–7
tinue to be particularly well-studied in this regard,
though
3
sp -carbon center bridges. It is suggested that decreasing the
saturation in the academic and patent literature has led many
8
–13
Cpcentroid–M–Cpcentroid angle of the metallocene will provide
researchers to pursue alternative frameworks.
Meanwhile,
analysis of
1
4–17
2,18–20
greater α-olefin co-monomer incorporation, possibly due to
the theoretical
and structure–activity
24
easier steric access to the cationic metal binding site. Further-
more, unlike traditional substituent variations on the Cp-rings,
altering the alkene substituents in such systems will allow for
the inductive perturbation of the electronics at the metal center
from afar, separating this effect from any steric considerations.
these discreet molecular systems advances our understanding
of the polymerization process itself, thereby driving the devel-
2
1–23
opment of new technology.
a
Department of Chemistry, University of Toronto, 80 St. George St, Toronto, Ontario,
Canada, M5S3H6. E-mail: dstephan@chem.utoronto.ca
Experimental section
General considerations
b
Saudi Basic Industries Corporation, P.O. Box 42503, Riyadh 11551, Saudi Arabia
†
CCDC 1003249–1003258. For crystallographic data in CIF or other electronic
format see DOI: 10.1039/c4dt01583e
Current address: SABIC Corporate Research and Innovation Center,
2
5
Compounds 2-bromoindene (1),
9-(dibromomethylene)-
2
6
27
fluorene (3),
(2,2-dibromoethene-1,1-diyl)dibenzene (4),
‡
2
8
29
P.O. Box 4545-4700, Jeddah-Thuwal, Kingdom of Saudi Arabia, 23955-6900.
4-(dibromomethylene)heptane (5), (Me N) ZrCl ·DME, and
2
2
2
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3
0,31
(Me
2
N)
2
TiCl
2
2 2
were prepared according to literature pre- 7.09 (s, 1H, CHCCH ), 3.52 (d, J = 1.8 Hz, 2H, CHCCH ),
cedent. All reactions were carried out and all metallocene 1.79–1.49 (m, 6H, CH CH CH CH ), 1.47–1.29 (m, 6H,
2
2
2
3
complexes were manipulated under an atmosphere of dry CH
unless otherwise noted. Hexanes, THF, Et O, PhMe, and (t, J = 7.3 Hz, 9H, CH
CH Cl were dried and deoxygenated using a solvent purifi- δ 149.92, 147.00, 145.56, 141.81 (JC–Sn = 16.4 Hz), 126.06,
2
CH
2
CH
2
CH
3
), 1.11–1.12 (m, 6H, CH
2
CH
2 2 3
CH CH ), 0.94
1
3
N
2
2
2
CH
2
CH
2
CH
3
). C-NMR (75 MHz, CDCl )
3
2
2
3
2
cation system in the manner of Grubbs, while PhH, PhCl, 123.92, 123.21, 119.97, 45.85 (JC–Sn = 20.8, 20.0 Hz), 29.23
and 1-hexene were distilled from CaH . All solvents were (JC–Sn = 10.5 Hz), 27.36 (JC–Sn = 28.5, 27.2 Hz), 13.69, 9.69
degassed and held over 4 Å molecular sieves prior to use. All (JC–Sn = 173, 166 Hz).
other reagents were commercially obtained and used as Synthesis of (C12
received. Preparative flash chromatography was performed Schlenk flask under N
2
H
8
)CvC(C
9
H
7
)
2
(6). In a flame-dried
3
3
2
atmosphere were combined 9-(dibromo-
on Silicycle P60 40–63 µm silica gel. NMR analysis was methylene)fluorene (3) (2.0 g, 5.95 mmol, 1.0 eq.) and tri-
obtained on Varian Mercury 400, Unity 500, and Brüker Avance butyl(1H-inden-2-yl)stannane (2) (6.03 g, 14.9 mmol, 2.5 eq.).
III 400 spectrometers. High-temperature GPC analysis for the Magnetic stirring commenced, and the contents were degassed
polymers was performed at Cornell University, Dept. of Chem- under vacuum for 15 min. The flask was purged with N , then
2
istry and Chemical Biology with polyethylene calibration. GPC charged with 30 mL anhydrous, degassed toluene. Pd
2 3
(dba)
analysis for the ethylene–1-hexene co-polymers was performed (272 mg, 0.30 mmol, 0.05 eq.) and t-Bu P (240 mg, 1.2 mmol,
3
at SABIC STC-Riyadh using a Waters Alliance GPC 2000 instru- 0.2 eq.) were combined in 3 mL anhydrous, degassed toluene
ment, with 1,2,4-trichlorobenzene as solvent at 150 °C. Density and syringed into the reaction mixture. This was followed by
analysis and differential scanning calorimetry were also per- three freeze–pump–thaw cycles, then reintroduction of N
2
formed at SABIC STC-Riyadh. Elemental analysis was per- atmosphere. The reaction mixture was then heated at 100 °C
formed by the University of Toronto, ANALEST facility, using a for 14 h. After this time, the solution was allowed to cool to
PerkinElmer 2400 Series II CHNS Analyzer. In some cases, ambient temperature, and KF (3.46 g, 59.5 mmol, 10 eq.) and
repeated attempts to acquire satisfactory elemental analyses 30 mL H O were added and the resultant biphasic mixture was
2
were unsuccessful.
Synthesis of (C
stirred vigorously for 1 h. The crude product was then filtered
(2). A Schlenk flask was charged through Celite, with EtOAc (100 mL) as additional elutant.
9
H
7
)SnBu
3
with a magnetic stir bar and Mg turnings (5.6 g, 231 mmol, 3.0 After aqueous separation with brine (30 mL), the organic layer
eq.) and flame-dried under vacuum. After cooling, the flask was dried with MgSO and concentrated by rotary evaporation
was purged to N , anhydrous THF was added to just cover the onto 2 g of silica. Column chromatography (5 → 10 → 20 →
4
2
turnings, and stirring was commenced. Two drops of 1,2- 30% PhMe–hexanes; the product can be seen as a red band)
dibromoethane were added as initiator, and a heat gun used provided the desired 6 (2.05 g, 85% yield) as a bright red solid.
1
to briefly reflux the contents, after which the flask was placed
3
H-NMR (200 MHz, CDCl ) δ 7.73 (d, J = 7.5 Hz, 2H, Harom),
in a 25 °C water bath. In a separate flame-dried flask under N2 7.46 (dd, J = 7.5, 5.2 Hz, 6H, Harom), 7.40–7.19 (m, 6H, Harom),
1
3
atmosphere, 2-bromoindene 1 (15.0 g, 76.9 mmol, 1.0 eq.) was 7.13–6.98 (m, 4H), 3.72 (s, 4H, CHCCH
dissolved in 75 mL anhydrous THF. A cannula was then used CDCl ) δ 148.45, 144.73, 143.99, 140.25, 138.49, 137.06, 134.96,
to transfer this solution onto the activated magnesium turn- 133.40, 127.67, 126.80, 125.35, 124.80, 123.96, 121.70, 119.49,
2
). C-NMR (101 MHz,
3
ings over 45 min, resulting in a red, opaque solution. After 40.95. Analysis calc’d for C32H
22 (406.52 g mol− ): C, 94.55; H,
1
1
.5 h, GC/MS analysis of an aliquot sample showed consump- 5.45; found: C, 94.08; H, 5.83.
tion of the 2-bromoindene. A separate flame-dried flask under
Synthesis of Ph CvC(C H ) (7). In the same manner as 6,
2 9 7 2
N
2 3
atmosphere was charged with n-Bu SnCl (22.9 mL, 7 was synthesized from (2,2-dibromoethene-1,1-diyl)dibenzene
8
0
4.6 mmol, 1.1 eq.) in 75 mL anhydrous THF and cooled to 4 (6.55 g, 19.4 mmol, 1.0 eq.), tributyl(1H-inden-2-yl)stannane
°C. To this was added, by cannula, the Grignard solution 2 (19.65 g, 48.5 mmol, 2.5 eq.), Pd (dba) (890 mg, 0.97 mmol,
2
3
3
over 20 min., and the reaction flask was brought to ambient 0.05 eq.), t-Bu P (790 mg, 3.9 mmol, 0.2 eq.) and KF (11.3 g,
temperature for an additional 20 min. The mixture was 19.5 mmol, 10 eq.) in dry toluene (100 mL). Column chromato-
quenched with chilled, saturated aq. NH Cl (50 mL) and the graphy (5 → 10 → 20 → 30 → 40% PhMe–hexanes; the product
4
organic phase was separated. The aqueous layer was extracted can be seen as a yellow band) provided 7 (5.17 g, 65% yield) as
1
with Et
2
O (50 mL × 3) and the combined organic layers were a bright yellow solid. H-NMR (400 MHz, CDCl
3
) δ 7.43–7.27
washed with brine (60 mL), dried over anhydrous MgSO , fil- (m, 16H, Harom), 7.24 (td, J = 7.2, 1.5 Hz, 2H, Harom), 6.84
4
1
3
tered, and concentrated to an orange oil. This was pushed (s, 2H, CHCCH
through a plug of activated, neutral alumina using hexanes, to CDCl ) δ 150.00, 144.61, 143.86, 143.77, 141.27, 134.11, 133.06,
provide, after removal of volatiles, the stannane 2 as a yellow 130.45, 128.06, 126.98, 126.23, 124.54, 123.36, 120.86, 41.25.
oil (27.7 g, ∼95 weight% purity by NMR) which was used Analysis calc’d for C32
without further purification. (The product is unstable to found: C, 93.61; H, 6.21.
normal SiO chromatography, while an attempt at vacuum dis- Synthesis of n-Pr CvC(C H ) (8). In the same manner as 6
) δ 7.51 except that 4-(dibromomethylene)heptane 5 was added once
d, J = 7.3 Hz, 1H, Harom), 7.42 (d, J = 7.4 Hz, 1H, Harom), 7.29 after stannane reagent was degassed, 8 was synthesized from 5
t, J = 7.3 Hz, 1H, Harom), 7.17 (td, J = 7.4, 1.1 Hz, 1H, Harom), (5.26 g, 19.5 mmol, 1.0 eq.), tributyl(1H-inden-2-yl)stannane 2
2 2
), 3.34 (s, 4H, CHCCH ). C-NMR (101 MHz,
3
H
24 (408.53 g mol− ): C, 94.08; H, 5.92;
1
2
2
9
7 2
1
tillation was unsuccessful). H-NMR (300 MHz, CDCl
3
(
(
13220 | Dalton Trans., 2014, 43, 13219–13231
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(19.8 g, 48.9 mmol, 2.5 eq.), Pd
2
(dba)
3
(890 mg, 0.97 mmol, CH
2
Cl
2
(5 mL), which after concentration provided 10a
0
1
.05 eq.), t-Bu P (790 mg, 3.9 mmol, 0.2 eq.) and KF (11.3 g, (210 mg, 56% yield) as a purple solid. Crystals suitable for
3
9.5 mmol, 10 eq.) in dry toluene (100 mL). Column chromato- X-ray diffraction could be grown by layering hexanes over a
1
graphy (5% PhMe–hexanes) provided 8 (4.8 g, 72% yield) as a concentrated solution of 10a in CH
slightly yellow, viscous oil. H-NMR (400 MHz, CDCl ) δ 7.30 CD Cl ) δ 7.58–7.53 (m, 4H, Harom), 7.49 (dd, J = 6.5, 3.1 Hz,
2
Cl
2
. H-NMR (400 MHz,
1
3
2
2
(
7
d, J = 7.4 Hz, 2H, Harom), 7.23 (dd, J = 14.1, 7.3 Hz, 4H, Harom), 4H, Harom), 7.40–7.26 (m, 10H, Harom), 6.18 (s, 4H, CHCCH).
1
3
.11 (td, J = 7.4, 1.1 Hz, 2H, Harom), 6.64 (s, 2H, CHCCH
2
), 3.26
2 2
C-NMR (101 MHz, CD Cl ) δ 144.60, 139.39, 133.72, 130.41,
(
(
s, 4H, CHCCH ), 2.36–2.04 (m, 4H, CH CH CH ), 1.56–1.36 128.92, 128.87, 128.78, 128.11, 127.16, 126.07, 114.83, 110.89.
2 2 2 3
m, 4H, CH
2
CH
C-NMR (100 MHz, CDCl
30.83, 129.89, 126.80, 124.66, 123.85, 121.04, 42.51, 34.94,
2
CH
3
), 0.84 (t, J = 7.3 Hz, 6H, CH
2 2 3 2 2 2
CH CH ). Analysis calcd for C32H22Cl Ti·CH Cl (612.24): C, 64.95;
1
3
3
) δ 148.78, 145.60, 143.65, 141.13, H, 3.96; found: C, 64.43; H, 3.84.
1
2
Synthesis of n-Pr CvC(C H ) TiCl (11a). In the same
2 9 6 2 2
2.53, 14.31. Analysis calc’d for C26
H
28 (340.50 g mol− ): manner as 9a except that a different purification method was
1
C, 91.71; H, 8.29; found C, 91.30; H 8.40.
employed, 11a was synthesized from 2,2′-(2-propylpent-1-ene-
Synthesis of (C H )CvC(C H ) TiCl (9a). In the glovebox, 1,1-diyl)bis(1H-indene) (8) (206 mg, 0.605 mmol, 1.0 eq.),
1
2
8
9
6 2
2
under N
2
3
2
atmosphere, a vial was charged with 9-(di(1H-inden- NaHMDS (233 mg, 1.27 mmol, 2.1 eq.) and (Me
-yl)methylene)fluorene (6) (73 mg, 0.180 mmol, 1.0 eq.) and (131 mg, 0.635 mmol, 1.05 eq.) in THF (6 mL), and Me
.6 mL THF. The mixture was stirred magnetically and cooled (0.45 mL, 3.6 mmol, 6.0 eq.) in CH Cl (5 mL). The dark
2
N)
2
TiCl
2
3
SiCl
2
2
to −35 °C, after which time solid NaHMDS (69 mg, residue was added to a small pipet packed with Celite and fil-
.377 mmol, 2.1 eq.) was added in one portion. The reaction tered through using CH Cl . Removal of solvent in vacuo, then
0
2
2
was allowed to warm slowly to ambient temperature and washing/decanting the resultant purple solid with pentanes
stirred for a total time of 5 h. The homogeneous solution was (5 mL × 3) provided 11a (130 mg, 47% yield) as a purple solid.
then cooled back to −35 °C and solid (Me
2 2 2
N) TiCl (39.1 mg, Crystals suitable for X-ray diffraction were grown by vial-in-vial
0
.189 mmol, 1.05 eq.) was added. The reaction mixture was solvent diffusion of a concentrated solution of 11a in CH Cl
2
2
1
allowed to warm slowly to ambient temperature and stirred with hexanes. H-NMR (400 MHz, C
6
D
6
) δ 7.47 (dd, J = 6.4,
overnight. After this time, the THF was removed in vacuo. The 2.9 Hz, 4H, Harom), 7.01 (dd, J = 6.4, 2.9 Hz, 4H, Harom), 5.65 (s,
residue was filtered through Celite with PhH (6 mL), concen- 4H, CHCCH), 2.19 (t, J = 7.4 Hz, 4H, CH CH CH ), 1.59–1.34
2
2
3
trated, and washed with pentanes (2 mL × 5) to remove trace (m, 4H, CH
2
CH
C-NMR (101 MHz, C
was dissolved in 1.5 mL CH Cl , after which Me SiCl (0.06 mL, 125.34, 114.60, 109.56, 33.16, 21.40, 13.99. Analysis calcd for
2
CH
3
), 0.86 (t, J = 7.3 Hz, 6H, CH
2 2 3
CH CH ).
1
3
remaining (Me
2
N)
2
TiCl
2
. The resultant dark purple residue
6 6
D
) δ 142.37, 133.49, 127.81, 125.71,
2
2
3
0
.46 mmol, 3.0 eq.) was added. The reaction mixture was
stirred magnetically for 12 h, then the volatiles were removed H, 5.88.
in vacuo. The purple residue was added to a small pipet packed Synthesis of (C H )CvC(C H ) ZrCl (9b). In the same
26 2
C H26Cl Ti (457.26): HC, 68.29; H, 5.73; found: C, 68.15;
1
2
8
9
6 2
2
with Celite. It was washed with PhH, which was then dis- manner as 9a except that a different purification method was
carded. The remaining solids were then filtered through using employed, 9b was synthesized from 9-(di(1H-inden-2-yl)-
PhCl, which after concentration and precipitation from methylene)fluorene (6) (92 mg, 0.226 mmol, 1.0 eq.), NaHMDS
hexanes provided 9a (38 mg, 48% yield) as a purple solid. Crys- (91.3 mg, 0.498 mmol, 2.2 eq.) and (Me
tals suitable for X-ray diffraction could be grown by vial-in-vial 0.237 mmol, 1.05 eq.) in THF (4 mL), and Me
solvent diffusion of a concentrated solution of 9a in PhCl with 1.8 mmol, 6.0 eq.) in CH Cl (5 mL). The residue washed with
2
N)
2
ZrCl
2
·DME (81 mg,
3
SiCl (0.18 mL,
2
2
1
hexanes. H-NMR (500 MHz, C
6 5 2
D Br) δ 7.84 (d, J = 7.7 Hz, 2H, Et O (2 mL × 2), then hexanes (6 mL × 3) to provide, after
H
arom), 7.81 (d, J = 7.6 Hz, 2H, Harom), 7.73 (dd, J = 6.5, 3.1 Hz, removal of trace solvent in vacuo, the desired 9b (114 mg, 89%
4
6
6
H, Harom), 7.47 (dt, J = 7.6, 1.1 Hz, 2H, Harom), 7.30 (dd, J = yield) as an orange, highly insoluble solid. Crystals suitable for
.4, 3.1 Hz, 4H, Harom), 7.17 (dt, J = 7.6, 1.1 Hz, 2H, Harom), X-ray diffraction were grown by slow precipitation of a PhMe–
1
3
1
6 5 6 6
.24 (s, 4H, CHCCH). C-NMR (partial, by gHMBC; C D Br) PhH solution. H-NMR (400 MHz, C D ) δ 7.60 (d, J = 7.7 Hz,
δ 141.5, 137.4, 133.9, 130.0, 128.4, 127.9, 126.3, 125.3, 120.7, 2H, Harom), 7.53 (d, J = 7.6 Hz, 2H, Harom) 7.50 (dd, J = 6.5,
1
13.1, 109.4. Analysis calc’d for C32
H
20Cl
2
Ti·C
6
H
5
Cl (634.05 g 3.1 Hz, 4H, Harom), 7.16 (dt, J = 1.0, 7.6 Hz, 2H, Harom), 6.97 (dd,
J = 3.1, 6.5 Hz, 4H, Harom), 6.88 (dt, J = 1.1, 7.6 Hz, 2H, Harom),
−
1
mol ): C, 71.78; H, 3.96; found: C, 71.92; H, 4.39.
1
3
Synthesis of Ph CvC(C H ) TiCl (10a). In the same 5.68 (s, 4H, CHCCH). C-NMR (100 MHz, C D ) δ 141.3, 137.4,
2
9
6 2
2
6 6
manner as 9a except that a different purification method was 129.5, 129.2, 128.5, 127.6, 127.1, 126.9, 125.3, 125.0, 120.3,
employed, 10a was synthesized from 2,2′-(2,2-diphenylethene- 116.6, 101.7. Analysis calc’d for C32 Zr·C Cl (681.20 g
,1-diyl)bis(1H-indene) 7 (295 mg, 0.72 mmol, 1.0 eq.), mol ): C, 67.20; H, 3.71; found: C, 66.90; H, 4.07.
NaHMDS (278 mg, 1.52 mmol, 2.2 eq.) and (Me N) TiCl Synthesis of Ph CvC(C ZrCl (10b). In the same
180 mg, 0.76 mmol, 1.05 eq.) in THF (6 mL), and Me SiCl manner as 9a except that a different purification method was
0.6 mL, 4.73 mmol, 6.5 eq.) in CH Cl (6 mL). The mixture of employed, 10b was synthesized from 2,2′-(2,2-diphenylethene-
H
22Cl
2
6 5
H
−
1
1
2
2
2
2
9
H
6
)
2
2
(
3
(
2
2
1
0a in CH
2
Cl
2
was concentrated and the dark residue was 1,1-diyl)bis(1H-indene) 7 (2 g, 4.90 mmol, 1.0 eq.), NaHMDS
O solution (1 mL × 2). The (1.98 g, 10.8 mmol, 2.2 eq.) and (Me N) ZrCl ·DME (1.91 g,
remaining solids were then filtered through Celite using 5.16 mmol, 1.05 eq.) in THF (50 mL), and Me SiCl (2.2 mL,
washed with a 3 : 1 pentane–Et
2
2
2
2
3
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1
7.3 mmol, 3.5 eq.) in CH
2
Cl
2
(25 mL). The mixture of 10b in (m, 4H, Harom), 7.14–7.07 (m, 2H, Harom), 3.58 (qd, J = 7.5,
CH Cl was concentrated and the resulting residue was dis- 3.8 Hz, 2H, CHCH ). 2.10 (d, J = 2.0 Hz, 6H, CCH ), 1.40 (d, J =
2
2
3
3
1
3
solved in CH
2
Cl
2
3 3
(5 mL), after which time slow addition of 7.6 Hz, 6H, CHCH ). C-NMR (100 MHz, CDCl ) δ 148.94,
hexanes causes precipitation of the desired complex. The 147.17, 145.04, 140.07, 138.46, 137.56, 137.12, 134.51, 127.60,
supernatant was decanted, and the procedure repeated, to give 127.18, 126.81, 125.71, 123.94, 122.65, 119.98, 119.23, 46.85,
+
1
0b (2.1 g, 71%) as a yellow powder. Crystals suitable for X-ray 15.23, 12.15. HRMS (m/z) calcd for C36
H
31[M + H ] 463.24258,
diffraction were grown by layering a concentrated solution of found 463.24230.
1
1
0b in CH Cl with pentane. H-NMR (400 MHz, C D )
Synthesis of (C H )CvC(C H Me ) (13). Under N atmos-
12 8 9 4 2 2 2
2
2
6
6
δ 7.57–7.47 (m, 4H, Harom), 7.39 (dd, J = 6.5, 3.1 Hz, 4H, phere, a vial was charged with 12 (185 mg, 0.4 mmol, 1.0 eq.)
arom), 7.10–6.93 (m, 6H, Harom), 6.90 (dd, J = 6.5, 3.1 Hz, 4H, and THF (10 mL). The mixture was stirred magnetically and
H
1
3
Harom), 5.62 (s, 4H, CHCCH). C-NMR (100 MHz, C D ) cooled to −35 °C, then solid NaN(SiMe ) (154 mg, 0.84 mmol,
6
6
3 2
δ 144.39, 139.64, 130.27, 128.67, 128.54, 128.51, 128.26 (found 2.1 eq.) was added in one portion; the reaction mixture
by gHMBC) 126.57, 124.86, 117.73, 102.64. Analysis calcd for immediately went to a deep purple color. The reaction was
C H Cl ·C H Cl (681.20): C, 67.00; H, 4.00; found: C, 67.19; allowed to warm slowly to ambient temperature and stirred for
3
2
22
2
6
5
H, 4.38.
Synthesis of n-Pr
a total time of 5 h. The homogeneous solution was then
2
CvC(C
9
H
6
)
2
ZrCl
2
(11b). In the same cooled back to −35 °C and solid (Me N) TiCl (86 mg,
2
2
2
manner as 9a except that a different purification method 0.42 mmol, 1.05 eq.) was added in one portion. The reaction
was employed, 11b was synthesized from 2,2′-(2-propylpent- mixture was allowed to warm slowly to ambient temperature
1
1
-ene-1,1-diyl)bis(1H-indene)
.0 eq.), NaHMDS (147 mg, 0.802 mmol, 2.1 eq.) and in vacuo. Hexane (16 mL) washed the residue solid and the
N) ZrCl ·DME (137 mg, 0.401 mmol, 1.05 eq.) in THF filtrate was vacuumed to give the product (13) (120 mg, 65%
8 mL), and Me
4 mL). The mixture of 11b in CH Cl was concentrated and J = 6.5 Hz, 2H, Harom), 7.70 (d, J = 7.1 Hz, 2H, Harom), 7.68–7.62
8
(130 mg, 0.382 mmol, and stirred overnight. After this time, the THF was removed
(
(
(
Me
2
2
2
1
3
SiCl (0.14 mL, 1.1 mmol, 3.0 eq.) in CH
2
Cl
2
2 2
yield) as a purple solid. H-NMR (400 MHz, CD Cl ) δ 7.86 (d,
2
2
the residue was washed with a 5 : 1 pentane–Et
1 mL × 2). The remaining solids were then filtered through
Celite using PhH (5 mL), which after concentration provided (s, 6H, CCH3). C-NMR (100 MHz, CD Cl ) δ 160.20, 150.15,
2
O solution (m, 2H, Harom), 7.52–7.47 (m, 2H, Harom), 7.44–7.38 (m, 4H,
(
H
arom), 7.37–7.27 (m, 4H, Harom), 1.99 (s, 6H, CvCCH ), 0.79
3
1
3
2
2
1
1
1b (155 mg, 81% yield) as a yellow solid. H-NMR (400 MHz, 148.01, 139.93, 139.35, 139.21, 130.96, 130.68, 127.73, 127.02,
) δ 7.47 (dd, J = 6.5, 3.1 Hz, 4H, Harom), 6.97 (dd, J = 6.5, 127.00, 126.78, 124.78, 123.55, 121.34, 119.92, 62.97, 18.23,
.1 Hz, 4H, Harom), 5.57 (s, 4H, CHCCH), 2.24–2.15 (m, 4H, 15.35. HRMS (m/z) calcd for C H [M + H ] 461.22693, found
36 29
6 6
C D
3
+
CH
2
CH
2
CH
3
), 1.59–1.35 (m, 4H, CH
2
CH
2
CH
3
), 0.86 (t, J = 461.22532.
) δ 143.01, Synthesis of (C12
1
3
7
1
1
.4 Hz, 6H, CH
2
CH
2
CH
3
). C-NMR (101 MHz, C
6
D
6
H
8
)CvC(C
9
H
4
2 2 2
Me ) ZrCl (14). In the glove-
29.08, 126.53, 125.70, 124.88, 118.16, 102.54, 33.09, 21.47, box, under N atmosphere, a vial was charged with 12 (140 mg,
3.98. Analysis calcd for C26
2
H
26Cl
2
Zr (500.61): C, 62.38; 0.3 mmol, 1.0 eq.) and THF (10 mL). The mixture was stirred
H, 5.23; found: C, 62.23; H, 5.41.
magnetically and cooled to −35 °C, then solid NaHMDS
Synthesis of (C H )CvC(C H Me ) (12). To a solution of 6 (122 mg, 0.63 mmol, 2.1 eq.) was added in one portion; the
1
2
8
9
5
2 2
(
(
1.3 g, 3.2 mmol, 1.0 eq.) in THF (20 mL) was added NaN- reaction mixture immediately went to a deep purple color. The
SiMe (1.2 g, 6.7 mmol, 2.1 eq.) in one portion at −35 °C. reaction was allowed to warm slowly to ambient temperature
3 2
)
The resulting purple solution was allowed to warm slowly to and stirred for a total time of 5 h. The homogeneous solution
ambient temperature and stirred for 3 h. Then the reaction was then cooled back to −35 °C and solid (Me N) ZrCl ·DME
mixture was cooled in an ice bath and MeI (1.9 g, 13.4 mmol, (107 mg, 0.31 mmol, 1.05 eq.) was added. The reaction mixture
.2 eq.) was added. After stirred overnight, the reaction was was allowed to warm slowly to ambient temperature and
quenched by saturated NH Cl solution (10 mL) and extracted stirred overnight. After this time, the THF was removed
by ether (30 mL × 2). The organic layer was dried over MgSO in vacuo. The brown residue was filtered through Celite with
filtered and concentrated to give the crude dimethylated inter- CH Cl (10 mL) and concentrated. The resulting solid was dis-
2
2
2
4
4
4
,
2
2
mediate (1.1 g). The dimethylated intermediate was dissolved solved in CH
in THF (30 mL) and cooled to −35 °C. LiN(SiMe (876 mg, 1.8 mmol, 3.0 eq.) was added. The reaction mixture was stirred
.25 mmol, 2.1 eq.) was added in one portion. The resulting magnetically at ambient temperature for 12 h, during which
2 2 3
Cl (10 mL), after which Me SiCl (194 mg,
3 2
)
5
solution was stirred at ambient temperature for 3 h. Then the time red precipitates crash out. The volatiles were removed
reaction mixture was cooled in an ice bath and MeI (1.7 g, in vacuo, and the residue washed with hexanes (15 mL). The
1
2.0 mmol, 4.8 eq.) was added. After stirred overnight, the supernatant was decanted off, and the residue washed with
reaction was quenched by saturated NH Cl solution (10 mL) further CH Cl (6 mL × 3) to provide, after removal of trace
4
2
2
and extracted by ether (30 mL × 2). The organic layer was dried solvent in vacuo, the desired 14 (112 mg, 60% yield) as a yellow
over MgSO , filtered and concentrated. The residue was recryst- solid. Crystals suitable for X-ray diffraction were grown by slow
4
1
allized by DCM and MeOH to give the product (12) (815 mg, precipitation of a CH
5% yield). H-NMR (400 MHz, CDCl
2
Cl
2
–hexane solution. H-NMR (400 MHz,
1
5
3 2 2
) δ 7.78 (ddt, J = 13.0, CD Cl ) δ 7.83 (dt, J = 7.6, 0.9 Hz, 2H, Harom), 7.58–7.49
8
.0, 0.9 Hz, 4H, Harom), 7.48–7.39 (m, 8H, Harom), 7.35–7.31 (m, 6H, Harom), 7.43 (td, J = 7.5, 1.1 Hz, 2H, Harom), 7.37–7.27
13222 | Dalton Trans., 2014, 43, 13219–13231
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Dalton Transactions
Paper
(
(
1
1
m, 4H, Harom), 7.16 (td, J = 7.6, 1.1 Hz, 2H, Harom), 2.46 CDCl
s, 12H, CCH3). C-NMR (100 MHz, CD Cl ) δ 141.00, 140.31, 121.61, 102.26, 99.47, 42.83, 0.16. HRMS (m/z) calcd for
2 2
3
) δ 143.97, 142.95, 138.41, 127.28, 126.86, 126.00, 123.65,
1
3
+
37.11, 129.82, 129.30, 127.78, 125.63, 124.20, 124.13, 123.53,
20.00, 114.02, 111.03, 14.72.
C
14
H
17Si [M + H ] 213.10995, found 213.11035.
Synthesis of (C )CuCH (18). To a solution of 17 (2.53 g,
9
H
7
Synthesis of (HO)CMe(C H ) (15). Under N atmosphere, a 11.9 mmol, 1.0 eq.) in THF (30 mL) was added dropwise a solu-
9
7 2
2
flask was charged with the indenyl Grignard solution, pre- tion of TBAF (14.4 mL, 1.0 M in THF, 14.4 mmol, 1.2 eq.) at
pared from 2-bromoindene (1.56 g, 8 mmol, 1.0 eq.) and Mg 0 °C. The resulting purple solution was allowed to warm to
turnings (0.576 g, 24 mmol, 3.0 eq.) in THF (16 mL). To this room temperature and stirred at this temperature for
1
flask was added acetyl chloride (234 mg, 3.0 mmol) dropwise 3.5 hours. H NMR of the crude mixture showed that the reac-
by syringe. The resulting mixture was stirred for another 1 h at tion was done. The mixture was diluted with hexane (100 mL),
room temperature. Then workup by NH Cl saturated solution washed with brine (30 mL × 1), dried over MgSO , filtered and
4
4
(
10 mL) and extracted by ether (50 mL). The organic layers was evaporated in vacuo. The residue was purified by silica gel
dried over MgSO , filtered and concentrated. The residue was column (hexane) to give 18 (1.61 g, 96% yield) as a yellow
further purified by silica gel column by Hexane to give the liquid. H-NMR (400 MHz, CDCl ) δ 7.42 (d, J = 7.6 Hz, 1H,
4
1
3
1
product (15) (207 mg, 25% yield). H-NMR (400 MHz, CDCl
δ 7.39–7.31 (m, 4H, Harom), 7.28–7.19 (m, 2H, Harom), 7.14 (td,
3
)
H
H
arom), 7.39 (d, J = 7.0 Hz, 1H, Harom), 7.29 (t, J = 7.6 Hz, 1H,
arom), 7.25 (dt, J = 7.4, 1.2 Hz, 1H, Harom), 7.16 (s, 1H,
J = 7.4, 1.2 Hz, 2H, Harom), 6.79 (dt, J = 1.6, 0.8 Hz, 2H, CHCCH ), 3.55 (s, 2H, CHCCH ), 3.30 (s, 1H, CuCH).
2
2
1
3
13
CHCCH
2
), 3.51–3.33 (m, 4H, CHCCH
2
), 1.85 (s, 3H). C-NMR
C-NMR (100 MHz, CDCl
3
) δ 143.74, 142.92, 138.95, 126.92,
(
1
C
100 MHz, CDCl ) δ 154.53, 144.52, 143.39, 126.57, 124.76, 126.21, 126.15, 123.71, 121.70, 81.96, 81.04, 42.72. HRMS (m/z)
3
+
23.83, 121.11, 73.65, 38.33, 28.93. HRMS (m/z) calcd for calcd for C H [M + H ] 141.07043, found 141.07048.
1
1
9
+
20
H
17[M − OH] 257.13303, found 257.13365.
Synthesis of (C
(58 mg, 0.1 mmol, 0.03 eq.) in THF (7 mL) was
15) (137 mg, 0.5 mmol, 1.0 eq.) in DCM (3 mL) was added added dropwise a solution of DIBAL-H (7.2 mL, 1.0 M in
9 7 2
H )CIvCH (19). To a suspension of
3 9 7 4 2
Synthesis of C HMe(C H ) (16). To a solution of compound Ni(dppp)Cl
(
some crystals of p-toluenesulfonic acid (10 mg, 0.05 mmol, 0.1 hexane, 7.2 mmol, 2.0 eq.) at room temperature. The mixture
eq.). The resulting solution was stirred at 40 °C for 1 h. The was stirred for 5 minutes then it was cooled down to 10 °C. A
solution was then washed with brine (10 mL) and extracted solution of 18 (0.5 g, 3.57 mmol, 1.0 eq.) in THF (5 mL) was
with DCM (10 mL × 2). The organic layers were dried over added and the resulting mixture was allowed to warm to room
2 4
Na SO , filtered and concentrated. The residue was further temperature and stirred at this temperature for 2 hours before
purified by silica gel column (hexane–DCM = 2 : 1) to give the a solution of iodine (2.7 g, 10.6 mmol, 3.0 eq.) in THF (20 mL)
1
product (16) (68 mg, 50% yield). H-NMR (400 MHz, CDCl
3
) δ was added at 10 °C. The mixture was then stirred at room
7
1
.67 (d, J = 7.1 Hz, 1H), 7.52–6.88 (m, 16H), 6.40 (d, J = 3.9 Hz, temperature for 40 minutes when TLC (hexane) showed the
1
3
H), 4.30–3.12 (m, 11H), 2.07–1.94 (m, 3H).
) δ 145.89, 145.70, 145.53, 144.43, 143.94, (60 mL), washed with aqueous Na
43.90, 143.53, 142.24, 141.70, 141.66, 138.56, 129.51, 127.12, MgSO , filtered and evaporated at 30 °C in vacuo. The residue
C-NMR reaction was done. The mixture was diluted with diethyl ether
(100 MHz, CDCl
3
2 2 3
S O
(30 mL), dried over
1
4
1
1
27.08, 127.00, 126.87, 126.68, 125.74, 125.71, 125.70, 125.56, was purified by basic alumina column (0 → 3% EtOAc–hexane)
25.15, 124.87, 124.78, 124.54, 124.40, 124.05, 123.48, 122.17, to give 19 (0.6 g, 63% yield) as a yellow solid. H-NMR
1
1
3
21.01, 57.53, 54.40, 53.77, 51.88, 47.25, 39.94, 39.47, 39.24, (400 MHz, CDCl
3
) δ 7.38 (dd, J = 6.4, 6.0 Hz, 2H, Harom), 7.27
+
5.77, 18.04. HRMS (m/z) calcd for C H [M + H ] 513.25283, (t, J = 7.6 Hz, 1H, Harom), 7.21 (dt, J = 7.4, 1.2 Hz, 1H, Harom),
4
0
33
found 513.25531.
Synthesis of (C
7.00 (s, 1H, CHCCH
2
), 6.46 (d, J = 1.6 Hz, 1H, CHHCI), 5.97 (d,
1
3
9
H
7
)CuCSiMe
3
(17). To a Schlenk flask was J = 1.6 Hz, 1H, CHHCI), 3.68 (s, 2H, CHCCH ). C-NMR
2
charged with 2-bromoindene (6 g, 30.8 mmol, 1.0 eq.), CuI (100 MHz, CD Cl ) δ 147.62, 144.02, 143.87, 138.44, 127.15,
2
2
(
(
0.59 g, 3.1 mmol, 0.1 eq.), THF (80 mL) and triethylamine 126.34, 124.33, 122.18, 102.55, 38.07. HRMS (m/z) calcd for
+
20 mL), and it was freeze–pump–thaw three times. Trimethyl-
C
11
H
10I [M + H ] 268.98272, found 268.98267.
silylacetylene (5.2 mL, 37.5 mmol, 1.2 eq.) and PdCl (PPh )
Synthesis of (C H ) CvCH (20). A Schlenk flask was
2
3 2
9
7 2
2
2
(0.6 g, 0.9 mmol, 0.03 eq.) was then added under N atmos- charged with a magnetic stir bar and Mg turnings (0.32 g,
phere. The resulting mixture was stirred at room temperature 13.3 mmol, 3.0 eq.) and flame-dried under vacuum. After
overnight, and TLC (hexane) showed the reaction was done. cooling, the flask was purged to N , anhydrous THF (6 mL)
2
The mixture was filtered and the filter cake was washed with was added to just cover the turnings, and stirring was com-
hexane (20 mL × 3). The combined filtrates was washed with menced. Several drops of 1,2-dibromoethane was added as
brine (50 mL × 1), dried over MgSO , filtered and evaporated initiator, and a heat gun used to briefly reflux the contents,
4
in vacuo. The residue was purified by silica gel column (0 → 5% after which the flask was placed in a 25 °C water bath. In a sep-
CH
2
Cl
2 2
–hexane) to give 2 (6 g, 92% yield) as a yellow solid. arate flame-dried flask under N atmosphere, 2-bromoindene
1
H-NMR (400 MHz, CDCl ) δ 7.40 (d, J = 7.2 Hz, 1H, Harom), (0.87 g, 4.5 mmol, 1.0 eq.) was dissolved in THF (12 mL).
3
7
7
(
.37 (d, J = 7.4 Hz, 1H, Harom), 7.28 (t, J = 6.8 Hz, 1H, Harom), A cannula was then used to transfer this solution onto the
.23 (t, J = 7.4 Hz, 1H, Harom), 7.11 (s, 1H, CHCCH ), 3.54 activated magnesium turnings over 5 min, resulting in a
s, 2H, CHCCH ), 0.25 (s, 9H, Si(CH ) ). C-NMR (100 MHz, red, opaque solution. This solution was stirred at room
2
1
3
2
3 3
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Dalton Transactions
temperature for 1.5 hours before it was added to a solution of X-ray diffraction were grown by vial-in-vial solvent diffusion of
ZnCl (1.2 g, 8.8 mmol, 2.0 eq.) in THF (12 mL) in a flame- a concentrated solution of 22 in benzene with pentane.
2
1
dried Schlenk flask at room temperature. The resulting
H-NMR (400 MHz, C
)CvCH ), 5.19 (s, 8H, CHCCH). C-NMR (100 MHz,
.4 mmol, 0.75 eq.) in THF (9 mL) and Pd(PPh3)4 (0.25 g, C D ) 141.90, 140.81, 134.75, 124.05, 123.13, 111.62, 103.22.
6 6
D ) δ 6.87–6.97 (m, 16H, Harom), 5.23
13
mixture was cooled to 0 °C, and a solution of 4 (0.9 g, (s, 4H, (C
H
9 6
2
3
0
6
6
.2 mmol, 0.05 eq.) were added subsequently in turn. The
2 9 6 2 2
Synthesis of H CvC(C H ) ZrCl (23). To a stirred solution
resulting mixture was slightly evacuated and then filled with of 20 (0.26 g, 1.0 mmol, 1.0 eq.) in benzene (15 mL) was added
N at 0 °C, and this process was repeated twice before it was NaN(SiMe3)2 (0.41 g, 2.2 mmol, 2.2 eq.) in one portion at
2
stirred at this temperature for 1.5 hours. To the mixture was 25 °C. The resulting yellow suspension was then stirred over-
added ethyl acetate (50 mL) and water (20 mL), and the night. The suspension was filtered, and the residue was
organic phase was separated. The aqueous layer was extracted washed with benzene (5 mL) and pentane (10 mL), dried
with ethyl acetate (30 mL × 2) and the combined filtrates were in vacuo. This yellow powder of di-sodium salt was added to a
washed with brine (20 mL × 1), dried over MgSO
evaporated in vacuo. The residue was purified by silica gel 1.05 mmol, 1.05 eq.) in toluene (10 mL) in portions, and the
column (0 → 5% CH Cl –hexane, 0.1% Et N was added) to resulting suspension was allowed to warm to room tempera-
4
, filtered and pre-cooled (−35 °C) suspension of ZrCl
4 2
(THF) (0.40 g,
2
2
3
1
give 20 (0.4 g, 56% yield) as a yellow solid. H-NMR (400 MHz, ture and stirred for 5 hours. The mixture was filtered through
CDCl ) δ 7.46 (d, J = 7.2 Hz, 2H, Harom), 7.38 (d, J = 7.6 Hz, 2H, celite and the filter cake was washed with benzene (3 mL). The
3
H
arom), 7.28 (t, J = 7.4 Hz, 2H, Harom), 7.21 (dt, J = 7.4, 0.72 Hz, combined filtrates were concentrated in vacuo. Prior to the
2
3
1
1
2
H, Harom), 7.01 (s, 2H, CHCCH ), 5.38 (s, 2H, (C )CvCH ), complete removal of solvent, excess hexane was added to pre-
2
9
H
7
2
1
3
.71 (s, 4H, CHCCH2). C-NMR (100 MHz, CDCl ) δ 146.60, cipitate the product, which was collected by filtration and
3
45.17, 142.90, 141.44, 130.41, 126.71, 125.15, 123.70, 121.30, dried under high vacuum to provide 23 (0.22 g, 52% yield) as a
+
1
13.83, 40.43. HRMS (m/z) calcd for C20
57.13303, found 257.13289.
H
17 [M + H ] yellow powder. H-NMR (400 MHz, C
2H, Harom), 7.41 (d, J = 3.08 Hz, 2H, Harom), 6.96 (d, J = 3.04
9 7 4 4 5
H ) C H (21). To a stirred solution of com- Hz, 2H, Harom), 6.94 (d, J = 3.08 Hz, 2H, Harom), 5.52 (s, 4H,
6 6
D ) δ 7.43 (d, J = 3.08 Hz,
Synthesis of (C
pound 20 (30 mg, 0.12 mmol, 1.0 eq.) and 1-hexene (0.15 mL, CHCCH), 5.29 (s, 2H, (C
.2 mmol, 10.0 eq.) in CD Cl (0.5 mL) was added a solution of CD Cl ) δ 138.12, 128.75, 126.82, 124.83, 117.77, 117.43,
1
3
9
6 2
H )CvCH ). C-NMR (100 MHz,
1
2
2
2
2
nd
Grubbs 2 generation catalyst (5 mg, 0.006 mmol, 0.05 eq.) in 101.76.
CD Cl (0.1 mL) at room temperature. The resulting brown solu- Synthesis of n-C
tion was then stirred overnight and H NMR showed the reac- solution of compound 23 (30 mg, 0.072 mmol, 1.0 eq.) and
tion was done. The mixture was concentrated and the residue 1-hexene (18 µL, 0.15 mmol, 2.0 eq.) in CH Cl (2 mL) was
was purified by silica gel column (0 → 3% EtOAc–hexane) to added a solution of Grubbs 2 catalyst (6.2 mg, 0.0073 mmol,
give compound 21 (25 mg, 81% yield) as a white solid. H-NMR 0.1 eq.) in CH Cl (1 mL) at room temperature. The resulting
2
2
4 9 9 6 2 2
H CHvC(C H ) ZrCl (24). To a stirred
1
2
2
nd
1
2
2
(400 MHz, CDCl
3
) δ 7.47 (d, J = 7.36 Hz, 1H), 7.41 (d, J = 7.36 brown solution was then stirred overnight before it was con-
Hz, 1H), 7.38 (t, J = 7.48 Hz, 1H), 7.34 (d, J = 7.52 Hz, 1H), centrated in vacuo. The residue was washed with pentane
7
1
.10–7.26 (m, 9H), 7.02 (t, J = 7.4 Hz, 2H), 6.90 (d, J = 7.68 Hz, (2 mL), and then taken up in CH Cl (1 mL). Excess hexane
2 2
H), 6.82 (s, 1H), 6.52 (s, 1H), 6.43 (s, 1H), 4.66 (s, 1H), 4.07 was added and the precipitate was discarded. The filtrate was
(
s, 2H), 3.73 (d, J = 22.4 Hz, 1H), 3.69 (s, 2H), 3.52 (d, J = then concentrated in vacuo to give compound 24 (9 mg, 28%
1
2
2
1
1
1
1
4
2.4 Hz, 1H), 3.09 (d, J = 23.2 Hz, 1H), 2.89 (d, J = 23.2 Hz, 1H), yield) as a yellow-pink powder. H-NMR (400 MHz, CD Cl )
2 2
1
3
3
.45–2.79 (m, 4H). C-NMR (100 MHz, CDCl ) δ 156.83, δ 7.54 (d, J = 3.2 Hz, 1H, Harom), 7.53 (d, J = 3.2 Hz, 2H, Harom),
50.79, 147.80, 145.26, 145.09, 144.76, 143.88, 143.61, 143.55, 7.51 (d, J = 3.2 Hz, 1H, Harom), 7.26 (d, J = 3.2 Hz, 2H, Harom),
41.91, 138.63, 130.39, 129.69, 128.13, 127.29, 126.94, 126.83, 7.25 (d, J = 3.2 Hz, 1H, Harom), 7.24 (d, J = 3.2 Hz, 1H, Harom),
26.76, 126.39, 125.76, 125.23, 125.12, 124.60, 124.28, 124.07, 6.21 (t, J = 8.0 Hz, 1H, CvCHCH
23.70, 123.61, 120.99, 120.95, 120.60, 56.03, 47.39, 41.53, (s, 2H, CHCCH), 2.40 (q, J = 8.0 Hz, 2H, CvCHCH
0.65, 39.30, 38.85, 37.51, 27.44. HRMS (m/z) calcd for C H J = 8.0 Hz, 2H, CH CH CH ), 1.44 (m, 2H, CH CH CH ), 0.96
2
), 6.03 (s, 2H, CHCCH), 6.01
2
), 1.58 (dd,
4
0
33
2
2
3
2
2
3
+
13
[
M + H ] 513.25823, found 513.25822.
Synthesis of (H CvC(C Zr (22). To a mixture of 20 δ 133.60, 129.13, 128.88, 126.75, 126.66, 124.89, 117.76,
50 mg, 0.2 mmol, 1.0 eq.) and NaN(SiMe3)2 (79 mg, 116.99, 102.64, 102.07, 31.75, 28.62, 22.51, 14.21.
.43 mmol, 2.2 eq.) was added benzene (4 mL) at 25 °C. The
resulting suspension was stirred at room temperature for over-
night. To this yellow-orange suspension was added pyridine These polymerizations were carried out using standard
50 μL, 0.62 mmol, 3.1 eq.) and ZrCl (THF) (78 mg, Schlenk-line techniques. A stock solution of 10 or 5 µmol pre-
.21 mmol, 1.05 eq.) in turn at room temperature. The mixture catalyst was prepared. In a Schlenk-flask, 1000 eq. MAO (10 wt%
2 2 3 6 6
(t, J = 7.6 Hz, 3H, CH CH CH ). C-NMR (100 MHz, C D )
2
9 6 2 2
H ) )
(
0
Schlenk-flask polymerization experiments
(
0
4
2
was stirred at room temperature for 3 hours before it was fil- soln in PhMe) was syringed into anhydrous PhMe (50 mL
tered through celite. The filtrate was concentrated in vacuo, PhMe was employed when 10 µmol pre-catalyst was used, and
washed by pentane, and dried under high vacuum to give 22 200 mL PhMe for 5 µmol pre-catalyst) and attached to a line
(
43 mg, 74% yield) as a brown powder. Crystals suitable for supplying 1 atm C H . Magnetic stirring was commenced at
2
4
13224 | Dalton Trans., 2014, 43, 13219–13231
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3
4
1
200 rpm. The flask was cycled between vacuum and ethylene were taken from the literature tabulations. The heavy atom
(×3), then placed in a 25 °C water bath. The pre-catalyst was positions were determined using direct methods employing
added via syringe; after 20 min, 10 mL of 10% (v/v) HCl in the SHELXTL direct methods routine. The remaining non-
MeOH was used to carefully quench the reaction, a needle hydrogen atoms were located from successive difference
being used to vent the evolved gas. An additional 150 mL of Fourier map calculations. The refinements were carried out by
MeOH was then added to fully precipitate any polymer. The using full-matrix least squares techniques on F, minimizing
2
2
resultant slurry was passed through filter paper and washed the function ω(F
o
− F
c
c o
) where the weight ω is defined as 4F /
2
with further MeOH. The recovered polymer was dried in a 2s (F ) and F and F are the observed and calculated structure
o
o
vacuum oven at 60 °C overnight before it was weighed and ana- factor amplitudes, respectively. In the final cycles of each
lyzed. Condition A: the same procedure as before, except 100 refinement, all non-hydrogen atoms were assigned anisotropic
eq. i-Bu Al was used in place of MAO, and the pre-catalyst and temperature factors in the absence of disorder or insufficient
3
3 6 5 4
[Ph C][B(C F ) ] were combined briefly before syringing into data. In the latter cases atoms were treated isotropically. C–H
the reaction flask. Copolymerizations with 1-hexene were per- atom positions were calculated and allowed to ride on the
formed in the same manner as in Condition A, except 5 mL carbon to which they are bonded assuming a C–H bond length
1
-hexene was added 1 min. prior to addition of the pre- of 0.95 Å. H-atom temperature factors were fixed at 1.20 times
catalyst.
the isotropic temperature factor of the C-atom to which they
are bonded. The H-atom contributions were calculated, but
not refined. The locations of the largest peaks in the final
Autoclave polymerization experiments
Into 5 ml anhydrous toluene was suspended 1 mg of the difference Fourier map calculation as well as the magnitude of
appropriate complex 9a, 10a, 11a, 9b, 10b, or (2-Ind) -1,1- the residual electron densities in each case were of no chemi-
2
2
biphenylZrCl . Methylaluminoxane (10 wt% soln in PhMe, cal significance.
M : Al = 1 : 1500) was added to the suspended complex (1.9 mL
MAO solution for 9a, 1.9 mL for 10a, 2.18 mL for 11a, 1.75 mL
for 9b, 2.08 mL for 10b and 1.83 mL for (2-Ind)
ZrCl ). After two minutes of shaking, the mixture was trans-
ferred under inert atmosphere into a 2 liter autoclave reactor
maintained at 60 °C and filled with 250 mL of iso-pentane and To synthesize the requisite ligands, 2-bromoindene (1) was
00 mL of 1-hexene. An ethylene pressure of 20 bar was first transformed to the corresponding Grignard reagent, then
applied for 1 hour. After releasing the pressure, the polymer transmetallated with tri-n-butyltin chloride to give the stan-
was filtered through an airless filter funnel, washed with nane (2-C )SnBu (2). Migita–Kosugi–Stille cross-coup-
with the gem-dibromides 3–5,
accomplished under palladium-catalyzed conditions, provid-
ing the ligand precursors R CvC(2-C (R = C12 6, Ph 7,
n-Pr 8). It is noteworthy that attempts to use 1H-inden-2-
2
-1,1-biphenyl-
2
Discussion
25
1
9
H
7
3
3
5,36
26–28
diluted hydrochloric acid (10 mL) water (10 mL) and acetone lings
10 mL) and finally dried in vacuum.
were then
(
2
9
H
7
)
2
H
8
1
-Hexene co-polymer quantification
1
3
37,38
39
C-NMR analysis was performed at 125 °C on a Varian 400 ylboronic acid
or its trifluoroborate salt for this later
spectrometer. Samples were prepared in 10 mm tubes, 10 wt% transformation gave very low yields.
polymer in 1,2,4-trichlorobenzene. A 5 mm sealed tube con-
The ligand dianions were most effectively generated by
taining C D Br was inserted within the 10 mm NMR tube to deprotonation with NaHMDS. Though subsequent salt meta-
6
5
serve as a deuterium lock. Parameter conditions for acquisition: thesis with the simple TiCl
3
, TiCl
N) TiCl
inverse gated H decoupling. Signals were integrated and ana- cleanly yielded the desired ansa-metallocenes. Finally, treatment
4
, or ZrCl
4
gave inconsistent
9
0° pulse angle, 33 s relaxation delay, 2 s acquisition time, and results, reactions with (Me
2
2
2
and (Me
2
N) ZrCl ·DME
2
2
1
2
1b
lyzed using the triad method developed by Hsieh and Randall.
with trimethylsilyl chloride provided the dichlorides R
C(2-C MCl (R = C12 , M = Ti: 9a, Zr: 9b; R = Ph, M = Ti:
0a, Zr: 10b; R = n-Pr, M = Ti: 11a, Zr: 11b) in yields ranging
Crystals were coated in Paratone-N oil in the glovebox, from 36–89% (Scheme 1).
mounted on a MiTegen Micromount and placed under an N All complexes were characterized by H- and C-NMR spectro-
2
Cv
H )
9 7 2
2
H
8
X-ray crystallography
1
1
13
2
1
stream, thus maintaining a dry, O -free environment for each scopy and elemental analysis. Indeed, the H-NMR spectra
2
crystal. The data were collected on a Bruker Apex II diffracto- of complexes 9–11 are informative in their characteristic
meter employing Mo Kα radiation (λ = 0.71073 Å). Data collec- indenyl singlets. The more electronegative titanium imparts
tion strategies were determined using Bruker Apex software further downfield chemical shifts than in the corresponding
and optimized to provide >99.5% complete data to a 2θ value zirconium complexes. Moreover, it is clear that as the alkene
of at least 55°. The data were collected at 150(±2) K for all crys- substituent become more electron withdrawing (fluorenyl >
tals. The frames were integrated with the Bruker SAINT soft- diphenyl > di-n-propyl), the chemical shift of the indenyl
ware package using a narrow-frame algorithm. Data were singlet also moves further downfield, inferring that the alkene
corrected for absorption effects using the empirical multi-scan substituents are also playing an electronic role at the metal
method (SADABS). Non-hydrogen atomic scattering factors center.
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Scheme 1 Synthesis of metallocene complexes. Conditions: (a) Mg,
cat. BrCH
Pd (dba) , 10 mol% t-Bu
–25 °C, then (Me N) ZrCl
Me SiCl, CH Cl , 25 °C.
2
CH
2
Br, THF, 25 °C, then n-Bu
P, 2.5 eq. 2, PhMe; (c) 2.2 eq. NaN(SiMe
·DME or (Me N) TiCl , 0–25 °C; (d) 3.0 eq.
3
SnCl, THF, 0 °C; (b) 5 mol%
2
2
3
3 2
)
, THF,
0
2
2
2
2
2
2
Fig. 2 POV-ray representation of complex (a) 9a, (b) 10a, (c) 11a, C:
3
2
2
black, Ti: violet, Cl: green. Hydrogens are omitted.
Crystals suitable for X-ray diffraction were obtained for the
three titanium complexes 9a, 10a and 11a (Fig. 2), as well as
for two of the zirconium complexes, 9b and 10b. In order to
obtain quantifiable information on hapticity, differences in
average metal to carbon bond lengths for the cyclopentadienyl-
like ring portion of the indenyl systems were examined. The
4
0
slip distortion parameter, (ΔM–C), measures the average
difference in distance between (a) the metal center and the
two carbons shared by the 5- and 6-membered rings of the
indenyl system and (b) the metal center and the three carbons
unique to the 5-membered ring. Considering the two zirco-
nium structures, the average (ΔM–C) value is calculated to be
Fig. 3 Geometrical parameters for metallocene complexes.
3
0
.160 Å for 9b and 0.158 Å for 10b. For comparison, the assum- with Ti shifted further towards η hapticity. Additionally, it
4
1
42
edly unstrained (Ind) ZrCl
and (Ind) ZrMe
have average appears that the alkene substituents play some role in the dis-
2
2
2
2
(
ΔM–C) values of 0.113 Å and 0.104 Å, respectively. Likewise, placement of the metal, with (ΔM–C) growing larger with
the titanium complex 9a has an average (ΔM–C) value of increasing electron-withdrawing effect. Finally, it is important
0
Ind
.218 Å, 10a of 0.202 Å, and 11a of 0.195 Å; the related to analyze the “openness” of the indene wedge. The most
4
2
2
TiMe
2
exhibits a value of 0.131 Å.
readily obtained value, Ct(1)–M–Ct(2) (α, Fig. 3), can be mis-
While these ansa species are then clearly more distorted leading, as a line connecting the metal to the indenyl centroid
than their parent unbridged structures, the slip parameters are is not necessarily normal (δ ≠ 90°) to the plane of that ring. It
small enough to place all complexes reported in this work is thus useful to consider the parameter β, the angle at which
5
within η hapticity. Still, it is apparent that for the two metals the indenyl planes would intersect were they to extend behind
studied, Zr exhibits a more natural fit into the ligand pocket, themselves into space.
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Simple geometrical analysis reveals that β = 360° − α − δ
1
−
Table 1 Selected bond lengths (Å) and angles (°)
δ . Wang has compiled an excellent review of metrical para-
2
a
2
9a
10a
11a
9b
10b
meters for a wide variety of ansa-metallocenes. Overall, single
3
sp carbon bridges give values for β in the range of 65.6–66.9°
M–Cl(1)
2.301(9) 2.3101(6) 2.321(1) 2.407(2) 2.4219(6)
2.302(5) 2.3219(6) 2.308(1) 2.4244(6)
for Ti and 69.5–72.8° for Zr metallocenes. Longer bridges, or M–Cl(2)
—
M–C(3)
single heteroatom linkages, invariably give smaller values. It is
M–C(4)
2.323(3) 2.342(2)
2.384(4) 2.355(2)
2.593(1) 2.539(2)
2.549(4) 2.563(2)
2.339(3) 2.376(2)
2.327(7) 2.343(2)
2.342(4) 2.365(2)
2.546(4) 2.567(2)
2.588(1) 2.569(2)
2.388(3) 2.365(2)
2.332(4) 2.451(6) 2.457(2)
2.364(4) 2.480(5) 2.457(2)
2.551(4) 2.626(5) 2.620(2)
2.527(4)
2.343(4)
also worth noting the values of ϕ (see Fig. 3) obtained from
M–C(5)
2
these crystal structures. An sp -hybridized carbon is expected M–C(10)
—
—
2.640(2)
2.488(2)
M–C(11)
to exhibit unstrained bond angles of ca. 120°. Indeed, for the
M–C(12)
b
2.331(4) 2.448(6)c 2.467(2)
crystal structure of a ligand based on 6, with triethylsilyl
M–C(13)
2.371(4) 2.475(4) 2.493(2)
d
groups on the indenyl rings, a value of ϕ = 117.2° was M–C(14)
2.555(4) 2.621(4) 2.633(2)
4
3
M–C(19)
M–C(20)
M–Ct(1)
2.537(4)
2.342(4)
2.103
—
—
2.223
2.215
2.615(2)
2.455(2)
2.224
observed. In the complexes reported here, the bond angles at
e
the bridging alkenyl carbon range between 101.3° and 104.5°.
2.120
2.121
2.114
2.122
5
e
This angle compression presumably results from the η -hapti- M–Ct(2)
2.105
2.224
city of indenyl group at the metal. The most closely related
complexes available in the literature are ansa-metallocenes
based on 2,2′-methylenebis(1H-inden-1-yl)zirconium dichlor- C(1)–C(2)–C(3)
α
121.84
99.15(6) 98.49
128.9(4) 126.26
121.07
121.67
100.24
129.07
128.62
102.04
120.33
121.61
118.05
163.03
163.23
85.10
117.02
103.95
126.94
128.55
104.51
128.26
126.63
105.11
163.14
163.60
85.81
115.97
100.09
128.01
128.16
103.83
121.11
121.74
117.14
164.41
163.27
85.98
Cl(1)–M–Cl(2)
C(1)–C(2)–C(12) 129.1(4) 132.39
102.28 101.35
C(2)–C(1)–R(1)f 127.3(4) 116.27
ide skeletons, three of which have been crystallographically
ϕ
4
4
3
f
analyzed. For these sp -bridged structures, the largest value
of ϕ obtained was 101.8°. In our series, the two comparable C(2)–C(1)–R(2)
127.28
105.85
164.20
163.77
83.71
84.04
70.41
15.80
16.23
125.20
118.52
163.79
164.15
84.94
84.63
69.36
16.21
15.85
R(1)–C(1)–R(2)
zirconium complexes 9b and 10b have ϕ = 104.5 and 103.8°,
ε
1
ε
2
δ
1
δ
2
3
2
respectively, inferring the change from sp to sp hybridization
at the bridge does enforce a more open indene–bridge–indene
angle.
84.76
68.47
16.97
16.97
85.92
71.25
16.86
16.40
86.48
71.57
15.59
16.73
β
Values obtained for the present methylidene bridges
γ
γ
1
(Table 1), particularly in the Ti series, are then touching at the
2
upper limits of β. Surprisingly though, the aforementioned
a
b
c
d
e
Averaged. M–C(8). M–C(10). M–C(11). Ct(n) refer to the centroids
44
f
2,2′-methylenebis(1H-inden-1-yl)zirconium dichloride systems,
of respective indenyl rings. R(n) refer to the connecting non-indenyl
carbons. ϕ: C(3)–C(2)–C(12); α: Ct(1)–M–Ct(2); ε
C(2)–C(12)–Ct(2); δ : M–Ct(1)–C(3); δ : M–Ct(2)–C(12).
1
: C(2)–C(3)–Ct(1); ε
2
:
while showing larger values for φ, maintain slightly smaller
values for α (115.2–115.6°) and larger values for β (74.2–76.9°)
compared to the zirconium complexes 10b and 11b. These
methylene-bridged complexes, however, contain alkyl or silyl
1
2
3
substituents on the indenyl rings, and hence steric repulsions ϕ angle to 106.7° with the average Zr–C distances to the η -
may explain this observation.
bound indenyl rings of 2.46(3) Å and longer Zr–C distances of
2
.501(8) and 2.61(1) Å.
An alternative strategy to derivatization of these metallo-
Further derivatization
Efforts to generate related alkylated ligands were undertaken. cenes targeted the synthesis of a terminal methylene analog of
To this end, derivative 6 was sequentially reacted with two 9–11. The idea was to then employ this species as a synthon
equivalents of NaN(SiMe
dimethylated ligand. Further treatment with LiN(SiMe
MeI afforded the tetramethylated ligand precursor (C H )- olefinic ligand precursor. Thus, treatment of indenyl Grignard
3
)
2
at −35 °C and MeI affording the for olefin metathesis to access a family of ligands. To this end,
3 2
)
and an initial approach targeted a dehydration strategy to the
1
2
8
CvC(C
Initial efforts to metallate 12 involved reaction with NaN- to prepare (HO)CMe(C
SiMe3)2 and subsequent treatment with (Me N) TiCl . Iso- lated pure in 25% yield. Efforts to dehydrate 15 using p-tolyl-
9
H
5
Me
2
)
2
(12) in 55% overall yield.
with acetyl chloride followed by an aqueous work-up was used
H )
7 2
(15), although it could only be iso-
9
(
2
2
2
lation and characterization of the product 13 revealed the sulfonic acid as a catalyst resulted in dehydration and
failure of this strategy to incorporate Ti. Instead the organic subsequent dimerization yielded C HMe(C (16) in 50%
product (C H )CvC(C H Me ) 13 was isolated in 65% yield, yield (Scheme 3). The nature of this product was confirmed
H )
9 7 4
3
1
2
8
9
4
2 2
in which the methylated indenyl rings are coupled (Scheme 2 crystallographically (Fig. 6).
and Fig. 4).
An alternative approach involved the high yielding synthesis
In contrast, reaction of 12 with two equivalents of NaN- of (C )CuCSiMe (17) from 2-bromoindene, Me SiCuCH
SiMe and (Me N) ZrCl
·DME afforded a new yellow species and triethylamine using PdCl (PPh /CuI as a catalyst. Sub-
in 60% isolated yield. NMR data were consistent with the for- sequent conversion of 17 to 18 was achieved in 96% yield by
mulation of this species as (C H )CvC(C H Me ) ZrCl (14). treatment with [Bu N]F. Reductive iodination of the alkyne
This was subsequently confirmed by X-ray methods (Fig. 5). proceeded via treatment with Ni(dppp)Cl , DIBAL-H and
While the overall geometry of 14 is analogous to that of 9a the iodine, affording (C )CIvCH (19) in 63% yield (Scheme 4).
impact of the methyl groups on the indenyl rings is to alter the Finally, reaction of 19 with the Mg, ZnCl and Pd(PPh yielded
H
9 7
3
3
(
3
)
2
2
2
2
2
3 2
)
1
2
8
9
4
2 2
2
4
2
H
7
9
2
3 4
)
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Scheme 3 Synthesis of 15–16.
Scheme 2 Synthesis of 12–14.
Fig. 6 POV-ray representation of complex 16. Hydrogens are omitted.
Fig. 4 POV-ray representation of complex 13. Hydrogens are omitted.
Fig. 5 POV-ray representation of complex 14. C: black, Zr: coral,
Cl: green. Hydrogens are omitted.
9 7 2 2
the desired 1,1-bis indenyl olefin, (C H ) CvCH (20), in 56%
nd
yield. Metathesis trials on 20 using Grubbs 2 generation cata-
lyst resulted in the formation of the cyclic dimeric species
(C
9
H
7
)
4
C
4
H
5
(21) which was isolated in 81% yield as a white
solid. Nonetheless, reaction of 20 with base and ZrCl (THF) at
4
2
room temperature led to the isolation of the bis-ligand Scheme 4 Synthesis of 17–24.
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atmospheric pressure conditions. Within a single metal series,
yield of polymer from the two aryl-containing systems 9 and 10
are relatively similar; however, the alkyl systems 11 are mark-
edly more active. Average molecular weights, moreover, do not
appear to trend with the alkenyl substituents. Comparing the
two metal systems, titanium consistently gave higher yields of
polyethylene and with higher average molecular weights than
zirconium.
As the metal center is comparatively exposed in these
systems, this could lead to chain transfer to the methylalumin-
oxane (MAO) co-catalyst, particularly with the zirconium pre-
catalysts. Consequently, 11a and 11b were run using i-Bu
alkylating agent/solvent scrubber and [Ph C][B(C
While this did increase the average molecular
weights of the resulting polymer, it came at the expense of
lower overall activities.
3
Al as
Fig. 7 POV-ray representation of complex 22. Hydrogens are omitted.
3
6 5 4
F )
] as
4
5,46
initiator.
2 9 6 2 2
complex, (H CvC(C H ) ) Zr (22). The nature of 22 was con-
firmed crystallographically (Fig. 7). These data confirmed the
5
formulation with two π-bound η -indenyl and two σ-bonded
The metallocenes 9–11 were also tested in 1-hexene–ethy-
lene co-polymerization experiments utilizing both Schlenk-line
and autoclave vessels (Tables 3 and 4, respectively). For com-
parative purposes, the known bis(1H-inden-2-yl)-1,1′-biphenyl-
rings. The latter give rise to Zr–C bond distances of 2.342(3)Å.
In contrast, performing the metallation procedures at −35 °C,
the Zr complex, H CvC(C H ) ZrCl (23), was readily prepared.
2 9 6 2 2
This afforded 23 in 52% yield as a yellow powder. Employing
4
7
zirconium dichloride
was also tested under identical
this species as a substrate for olefin metathesis with 1-hexene
conditions, as the biphenyl moiety of this complex was
expected to provide a similar inductive effect as the aryl groups
in complexes 9b and 10b. However, the difference in geometry
nd
and again employing of Grubbs 2 generation catalyst afforded
the product n-C H CHvC(C H ) ZrCl (24) in 28% yield
4
9
9
6 2
2
(Scheme 4).
(
α = 132°) putatively provides a less open metallocene.
While activity measurements between Tables 3 and 4
cannot be directly compared, it is evident that the increased
Polymerization results
The synthesized complexes were tested for their ethylene quantity of polymer produced occurs as a result of 1-hexene
polymerization activities in Schlenk-flask trials (Table 2) under
a
Table 2 Ethylene polymerizations
Table 3 Ethylene–1-hexene copolymerization (low pressure)
Precat.
μmol)
MAO
Vol
Yield Act.
M
(Da)
w
Act.
Hexene incorp.
(mol %)
(g mmol− h−1
1
)
PDI Precat.
Yield (g)
(g mmol h−1
)
−1
(
(mmol) (mL) (g)
9
1
1
1
9
1
1
1
a (10)
0a (10) 10
1a (5)
1a (10)
b (10)
0b (10) 10
1b (10) 10
10
50
50
200
50
50
50
1.86
1.60
4.10
1.68
1.51
1.16
2.06
1.51
560
480
2460
500
450
350
122 000 3.6
154 000 3.8
137 000 3.3
145 000 3.3
2500 2.0
2800 1.8
2500 1.8
9a
10a
11a
9b
10b
11b
BIBPZrCl
2
5.42
5.09
6.50
3.94
3.72
6.58
1.53
1620
1530
1950
1180
1120
1970
461
17.2
15.2
8.4
28.2
28.4
16.8
6.6
10
A
10
a
200
50
1240
450
1b (10)
A
4900 2.5
Conditions: 10 μmol precat., 10 mmol MAO, 1 atm C
2 4
H , 5 mL
a
Conditions: 1 atm C
1 μmol [Ph C][B(C
2
)
H
4; 25 °C, 20 min PhMe. A: 1 mmol iBu
3
Al, 1-hexene, 50 mL PhMe, 25 °C, 20 min. Hexene incorporation determined
1
3
a
1
3
6
F
5
4
].
2 2 2
by C-NMR analysis. BIBPZrCl = (2-Ind) -1,1-biphenylZrCl .
Table 4 Ethylene–1-hexene copolymerization, autoclave experiments
Productivity
(gcopol/gprecat
Density
−1
a
Precat.
)
Branching
(g mL
)
M
w
(Da)
PDI
T
c
(°C)
m
T (°C)
9
1
1
9
1
a
103 000
28 000
96 000
19 000
27 000
79 000
13.67
17.68
20.51
117.02
115.97
16.34
0.9392
0.9317
0.9246
0.9330
0.9345
0.9398
292 500
313 000
122 500
2700
3100
381 000
3.1
2.9
2.2
1.8
1.9
2.3
113
115
110
98
100
117
127
129
122
106
109
131
0a
1a
b
0b
b
2
BIBPZrCl
a
Conditions: 1 mg precat., MAO (M : Al ratio 1 : 1500), 20 bar C
BIBPZrCl = (2-Ind) -1,1-biphenylZrCl .
2 2 2
2 4
H
, 100 mL 1-hexene, 250 mL iso-pentane, 60 °C, 1 h. Per 1000 carbon atoms.
b
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3
mers probably causes an inflation in this value: the C-NMR
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6 P. Margl, L. Deng and T. Ziegler, J. Am. Chem. Soc., 1998,
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Conclusion
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This study has detailed the synthesis of a new class of titanium 18 H. Alt and A. Köppl, Chem. Rev., 2000, 100.
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ations from ideal sp -hybridized carbon bond angles in the 20 C. E. D. Zachmanoglou, A. Bridgewater, B. M. Parkin,
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13230 | Dalton Trans., 2014, 43, 13219–13231
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4
4
4
1 T. Repo, M. Klinga, I. Mutikainen, Y. Su, M. Keskelä and 44 L. Resconi, I. Camurati, C. Fiori, D. Balboni, P. Mercandelli
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3 Formula: C H Si ; 635.02 g mol ; triclinic, P ˉ1 ; a = 8.397(1), 46 N. N. Bhriain, H.-H. Britzinger, D. Ruchatz and G. Fink,
−1
44
50
2
b = 12.138(1), c = 18.422(2) Å; α = 103.273(6), β = 93.615(7),
Macromolecules, 2005, 38, 2056–2063.
−
3
γ = 92.848(6)°; Z = 2; dcalc = 1.159 g cm ; abs. coeff. 47 W. W. Ellis, T. K. Hollis, W. Odenkirk, J. Whelan,
0
0
.127 mm− , refl. collected: 42 063, unique: 11 574; R1
1
=
R. Ostrander, A. L. Rheingold and B. Bosnich, Organometallics,
1993, 12, 4391–4401.
.0455; wR = 0.1347.
2
This journal is © The Royal Society of Chemistry 2014
Dalton Trans., 2014, 43, 13219–13231 | 13231