Preparation of phosphine-amido hafnium and zirconium complexes for olefin polymerization

Article abstract of DOI:10.1021/om400899g

Aniline (N-R-C₆H₅NH) and 1,2,3,4-tetrahydroquinoline (2-R-C₉H₉NH) derivatives were ortho-lithiated via conversion of the respective -NH groups to -N(COOLi), followed by treatment with tBuLi. The resulting ortho-lithiated compounds were transformed to ortho-Ph₂P-substituted derivatives on treatment with Ph ₂P(OPh). Further reaction of the resulting compounds with M(CH ₂Ph)₄ (M = Zr, Hf) afforded a series of Hf and Zr complexes: (2-R-8-Ph₂PC₉H₉N)Hf(CH ₂Ph)₃ (8, R = H; 9, R = Me; 10, R = iPr; 11, R = nBu), (N-R-2-Ph₂PC₆H₄N)Hf(CH₂Ph) ₃ (12, R = Me; 13, R = Et; 14, R = iPr), (2-R-8-Ph₂PC ₉H₉N)Zr(CH₂Ph)₃ (15, R = H; 16, R = Me; 17, R = iPr; 18, R = nBu), and (N-R-2-Ph₂PC₆H ₄N)Zr(CH₂Ph)₃ (19, R = Me; 20, R = Et)]. X-ray crystallographic studies of 9, 14, 16, and 19 revealed a distorted trigonal-bipyramidal structure with two benzyl moieties in equatorial positions and the remaining benzyl ligand occupying an apical position; in solution, however, three benzyl ligands became scrambled, as evidenced by a single set of benzyl signals in the corresponding ¹H NMR spectra. The complexes showed comparable activities (17-48 × 10⁶ g/mol-M·h) to the Ti-based constrained geometry catalyst (CGC) (36 × 10⁶ g/mol-Ti·h) in ethylene/1-octene copolymerization, despite their inferior 1-octene incorporation capabilities (3-8 mol % versus 17 mol %). Compound 15 showed a moderate 1-octene incorporation capability (7.7 mol %), whereas the others showed low 1-octene incorporations (2-4 mol %). Compounds 9 and 16 provided high-molecular-weight polymers with M_w > 200 000 even at high reaction temperatures of 100-130 C.

Full text of DOI:10.1021/om400899g

Article
pubs.acs.org/Organometallics
Preparation of Phosphine-Amido Hafnium and Zirconium Complexes
for Olefin Polymerization
Sung Hae Jun,† Ji Hae Park,† Chun Sun Lee,† Seong Yeon Park,† Min Jeong Go,‡ Junseong Lee,‡
and Bun Yeoul Lee*,†
†Department of Molecular Science and Technology, Ajou University, Suwon 443-749, South Korea
‡Department of Chemistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 500-757, South Korea
S
* Supporting Information
ABSTRACT: Aniline (N-R-C6H5NH) and 1,2,3,4-tetrahydroquinoline (2-
R-C9H9NH) derivatives were ortho-lithiated via conversion of the
respective −NH groups to −N(COOLi), followed by treatment with
tBuLi. The resulting ortho-lithiated compounds were transformed to ortho-
Ph2P-substituted derivatives on treatment with Ph2P(OPh). Further
reaction of the resulting compounds with M(CH2Ph)4 (M = Zr, Hf)
afforded a series of Hf and Zr complexes: (2-R-8-Ph2PC9H9N)Hf(CH2Ph)3
(8, R = H; 9, R = Me; 10, R = iPr; 11, R = nBu), (N-R-2-
Ph2PC6H4N)Hf(CH2Ph)3 (12, R = Me; 13, R = Et; 14, R = iPr), (2-R-8-
Ph2PC9H9N)Zr(CH2Ph)3 (15, R = H; 16, R = Me; 17, R = iPr; 18, R =
nBu), and (N-R-2-Ph2PC6H4N)Zr(CH2Ph)3 (19, R = Me; 20, R = Et)]. X-ray crystallographic studies of 9, 14, 16, and 19
revealed a distorted trigonal-bipyramidal structure with two benzyl moieties in equatorial positions and the remaining benzyl
ligand occupying an apical position; in solution, however, three benzyl ligands became scrambled, as evidenced by a single set of
benzyl signals in the corresponding 1H NMR spectra. The complexes showed comparable activities (17−48 × 106 g/mol-M·h) to
the Ti-based constrained geometry catalyst (CGC) (36 × 106 g/mol-Ti·h) in ethylene/1-octene copolymerization, despite their
inferior 1-octene incorporation capabilities (3−8 mol % versus 17 mol %). Compound 15 showed a moderate 1-octene
incorporation capability (7.7 mol %), whereas the others showed low 1-octene incorporations (2−4 mol %). Compounds 9 and
16 provided high-molecular-weight polymers with Mw > 200 000 even at high reaction temperatures of 100−130 °C.
[N,N,C]-HfX2 complexes have been successfully utilized in
chain shuttling polymerization reactions.23−27 Similar types of
pyridine-2-phenolate-6-(σ-aryl) derived complexes were also
reported.28,29 Phosphine and its related ligands have rarely been
utilized in the construction of group-4-metal based polymer-
ization catalysts.30−32 In this work, we report fabrication of
LMX3-type complexes constructed using phosphine-amido
ligands and examine their olefin polymerization reactivities.
INTRODUCTION
■
Currently, approximately 5 million tons of polyethylene (PE)
and 1.5 million tons of polypropylene (PP) are produced
annually using single-site homogeneous Ziegler catalysts.1
Methyl aluminoxane (MAO)-activated group 4 metallocenes
were introduced as single-site homogeneous Ziegler catalysts by
Kaminsky;2 catalytic species were later expanded to half-
metallocenes constructed with a cyclopentadienyl and an amido
ligand.3−5 Single-site polyolefin catalysts were further extended
to postmetallocenes comprising noncyclopentadienyl ligand
systems.6−9 Most of the known single-site polyolefin catalysts
have the common structure “LMX2”. The spectator ligand L,
attached permanently to the metal center, imparts an electronic
and a steric influence to the metal center. One of the ligands X
(alkyl) is abstracted by an activator to generate a cationic metal
center, while the polymer chain grows from the other X moiety.
Different types of highly active catalysts possessing the “LMX3”
structure (M: Zr or Hf; L: ether-amido ligand; X: benzyl) were
discovered by Dow and Symyx by high-throughput screening
methods;10 since this discovery, the spectator ligand L has been
further diversified to include imine-amido, imine-enamido, and
aminotroponiminato derivatives for use in catalytic olefin
polymerization.11−16 These species were followed by reports of
[N,N,C]-HfX2 complexes based on the pyridine-amido ligand
system, incorporating ortho-metalated aryl moieties;17−22 such
RESULTS AND DISCUSSION
■
Ligand Synthesis. We have previously developed a simple
protocol for the directed ortho-lithiation of tetrahydroquinoline
derivatives, which allows the facile construction of a series of
half-metallocenes.33−35 Several half-metallocenes prepared by
this method showed excellent catalytic performances in
ethylene/α-olefin copolymerization reaction, with potential
applicability in commercial processes.36,37 The lithium
carbamate [−N(COOLi)] group, generated from tetrahydro-
quinoline derivatives by sequential treatment with n-BuLi and
CO2, acts as a directing group in the directed ortho-lithiation
process, facilitating the deprotonation of the aryl ortho-proton
upon treatment with tBuLi (Scheme 1). Advantageously, the
Received: September 6, 2013
Published: November 27, 2013
© 2013 American Chemical Society
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Scheme 1. Ligand Synthesis
Chart 1. Metal Complexes Prepared Using Phosphine-
Amido Ligands
original amino group (−NH−) is easily recovered during the
acidic workup procedure. Katritzky attempted ortho-lithiation
of the lithium carbamate of tetrahydroquinoline over two
decades ago by treatment with tBuLi−KOtBu in THF. The
resulting product was not the ortho-lithiated analogue; rather,
an α-lithiated product was obtained.38 We observed that the
treatment of a tetrahydroquinoline-derived lithium carbamate
in a nonpolar solvent (diethyl ether) with tBuLi containing a
residual amount of THF yielded the desired ortho-lithiated
product; when this product was reacted with chlorodiphenyl-
phosphine (Ph2PCl), a negligible amount of the desired
product was obtained. We attributed this failure to the high
reactivity of Ph2PCl, which might react not only with the ortho-
lithiated carbon nucleophile but also with the carbamate anion.
Replacing Ph2PCl with the less reactive reagent Ph2P(OPh)
afforded the desired products (1−4) in fair yields (50−77%,
Scheme 1). Further, compound purification could be achieved
using column chromatography without aerobic oxidation. The
synthesis of 2 was recently reported; however, its preparation
required a tedious five-step procedure from an expensive
bipyramidal structure, in which two benzyl ligands and a
phosphine ligand formed a plane with the metal center, while
the remaining benzyl and amido ligand occupied the apical
sites. The apical and equatorial benzyl ligands were expected to
appear differentiated if the solid structure persisted in the
solution; however, only a single benzyl-CH2 signal was
observed, indicating that the three benzyl ligands rapidly
scrambled in solution. In the 1H NMR spectra of 9−11
prepared from chiral ligands, the benzyl-CH2 signals were
observed at 2.5 ppm (dd, J = 12 and 2.4 Hz) and 2.3 ppm (d, J
= 12 Hz) with an equal integration value. Because of the
presence of a chiral center, the two benzyl methylene protons
were diastereotopic, exhibiting distinct chemical shifts with a
large geminal coupling constant (2JH−H = 12 Hz). Further
coupling, as noted by the accompanying smaller coupling
constant, was attributed to coupling with the phosphorus atom
(3JP−H = 2.4 Hz). The 31P signals were observed at 30−33 ppm
after Hf metal coordination, corresponding to a distinct upfield
chemical shift from that observed for the free ligands (−20
ppm). For 10, the 31P signal was observed at 19 ppm, a
deviation from the chemical shifts of the other complexes (30−
33 ppm).
starting material (8-bromoquinoline).39 The H, 13C, and 31P
1
NMR spectra and high-resolution mass data were in good
agreement with the expected structure.
By employing the same ortho-lithiation method,40 N-R-2-
(diphenylphosphanyl)anilines (R = Me, Et, iPr) were prepared
from N-alkylanilines (Scheme 1). In our previous report, ortho-
lithiation was not facile for substrates bearing sterically bulky
substituents around the nitrogen atom, such as N-isopropylani-
line.40 We determined that difficulties arose during the CO2-
addition step, which was resolved by replacing diethyl ether
the reaction solvent used in this stepwith THF. Katritzky
previously reported the ortho-lithiation of N-methylaniline,41
which was successfully utilized by others in the preparation of
N-methyl-2-(diphenylphosphanyl)aniline (5).42−44 Synthesis of
N-ethyl-2-(diphenylphosphanyl)aniline (6) was also reported
by a different route, but as a mixture of para-isomers in low
yield (25%).45
The same procedure and conditions used for the synthesis of
Hf complexes afforded the Zr complexes 15−20 when
Zr(CH2Ph)4 was used. The reaction rate for the formation of
17 was comparatively slow, requiring 3 days, whereas the other
complexes were afforded after stirring overnight. Reaction of N-
isopropyl-2-(diphenylphosphanyl)aniline did not afford the
desired Zr complex; instead, a black intractable solid was
Metalation and Activation Reaction. The overnight
reaction of 1−7 with Hf(CH2Ph)4 in toluene at room
temperature afforded the desired complexes 8−14, respectively,
in good yields (71−82%, Chart 1). The rate of metalation
depended on the ligand structure. For 8 and 9, the metalation
completed in several hours, but for the others, it needed
overnight stirring for the completion. Yellow powders were
isolated by trituration in hexane, which were clean according to
1
formed. The H NMR spectra of the Zr complexes exhibited
the same benzyl methylene proton signal pattern in almost the
same region as was observed for the Hf complexes, indicating
that all three benzyl ligands were equivalent because of rapid
scrambling. The 31P signals were observed at 22−24 ppm,
downfield-shifted from the chemical shifts observed for the Hf
complexes. For 17, the 31P signal was also observed at 17 ppm,
deviating from the chemical shifts of other Zr species in a
manner similar to that of the Hf complexes. It is suggested that
the steric influence of the isopropyl group provided interference
at the metal center, resulting in the slower metalation reaction
1
the H NMR spectral analysis. The NH signals observed at
4.7−5.0 ppm in the 1H NMR spectra of 1−7 disappeared in the
1
corresponding spectra of 8−14. In the H NMR spectra of 8
and 12−14 prepared from achiral ligands, a single benzyl-CH2
signal was observed at 2.4 ppm as a singlet, indicating that the
three benzyl ligands were equivalent in solution. As shown in
Figure 2, the crystalline complexes adopted a distorted trigonal-
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rate and shift in the 31P signals from the typical values observed
for the other complexes. Contrary to the failure in metalation of
the related amine-based ligand systems, titanium complex 21
was successfully prepared, possibly by the aid of a phosphine
unit, according to the same procedure and conditions using
Ti(CH2Ph)4. A single benzyl-CH2 signal was also observed at
3.5 ppm as a singlet, and a 31P signal was observed at 29 ppm.
The Hf and Zr complexes were yellowish solids, whereas the
titanium complex was a reddish brown solid.
the Hf center were observed at 5.7 ppm as a doublet (3JP−H
=
7.2 Hz), significantly downfield-shifted from the chemical shift
observed for 8 (2.4 ppm). The significant change in the
chemical shift is thought to be due to a change in the hapticity
(from η1 to η3) of the benzyl ligand. The −CH2N− signal was
fairly upfield-shifted from 3.4 ppm in 8 to 2.3 ppm in 22. The
complex was stable in the solution; therefore, negligible
changes were observed in the 1H NMR spectrum after allowing
the NMR sample in the solution to stand at room temperature
for 3 h. However, the appearance of an additional unassigned
Hf-CH2Ph doublet signal at 6.2 ppm was observed when the
sample was kept overnight in the solution. The assignment was
also confirmed by the analysis of the 1H NMR spectrum of 23.
The methylene signal in [PhCH2B(C6F5)3]− was observed at
the same chemical shift (3.5 ppm, singlet) as that found in 22.
The −CH2Ph signal corresponding to the other two benzyl
groups on Hf was observed in the region similar to that for 22;
however, the signal was split into two doublet signals at 6.0 and
5.7 ppm because of the presence of a chiral center in the ligand
framework. The −CHN− signal was also upfield-shifted from
4.0 ppm in 11 to 3.1 ppm in 23. Furthermore, 23 was more
When 1 equiv of B(C6F5)3 was added to a solution of 8 in
C6D6, an oily compound was deposited, which became soluble
by the addition of a small amount of C6H5Cl.46 The H NMR
1
spectrum was quite clean and assignable to the structure of ion-
paired complex 22 (Chart 1 and Figure 1). The methylene
1
stable in solution than 22; the H NMR spectrum remained
unchanged even after keeping the sample in the solution for 1
day. In the 19F NMR spectra, only a set of signals was observed
at −130.6, −164.1, and −166.9 ppm, assignable to a solvent
separated free anion.15 In related amidoquinoline complexes,
two sets of 19F NMR signals were observed: one was a solvent
separated free anion and the other minor was a coordinated
ion.15 When ethylene gas was fed into the NMR cell containing
23, rapid consumption of ethylene was observed with formation
of polymer precipitates.
1
Figure 1. H NMR spectra of 8 and 22.
signal in [PhCH2B(C6F5)3]− was observed at 3.5 ppm as a
singlet, while that of the other two benzyl moieties attached at
Figure 2. Thermal ellipsoid plots (30% probability level) of 9 (a), 14 (b), 16 (c), and 19 (d). Hydrogen atoms are omitted for clarity.
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Table 1. Selected Bond Distances (Å) and Angles (deg) in 9, 14, 16, and 19
9 (Hf)
14 (Hf)
16 (Zr)
19 (Zr)
M−P
M−N
M−C(eq 1)
M−C(eq 2)
2.735(1)
2.086(3)
2.250(6)
2.217(7)
2.306(6)
101.3(4)
116.0(4)
125.5(4)
130.20(16)
113.98(15)
115.54(17)
151.43(18)
93.5(2)
2.6808(5)
2.109(2)
2.7558(6)
2.104(2)
2.7498(7)
2.113(2)
2.316(2)
2.285(3)
2.319(2)
2.232(2)
2.271(3)
2.247(2)
2.246(3)
M−C(apical)
2.293(2)
2.322(3)
M−C(eq 1)−C
M−C(eq 2)−C
M−C(apical)−C
P−M−C(eq 1)
C(eq 1)−M−C(eq 2)
C(eq 2)−M−P
N−M−C(apical)
C(apical)−M−C(eq 1)
C(apical)−M−C(eq 2)
C(apical)−M−P
N−M−C(eq 1)
N−M−C(eq 2)
N−M−P
116.88(14)
102.26(13)
128.53(15)
112.38(6)
118.07(8)
129.46(6)
152.81(7)
96.50(8)
101.9(2)
101.48(15)
85.48(14)
125.57(16)
130.34(7)
134.6(1)
111.5(2)
126.9(2)
129.40(9)
116.87(11)
113.47(10)
149.36(9)
93.99(12)
98.28(13)
83.51(7)
95.06(7)
145.08(9)
89.37(9)
98.1(2)
92.44(8)
98.89(10)
81.53(7)
84.64(15)
96.11(17)
102.33(18)
68.64(10)
134.9(3)
110.8(3)
113.9(4)
84.63(6)
101.44(7)
96.87(7)
96.15(11)
102.69(10)
67.76(5)
95.24(9)
102.14(9)
69.18(6)
69.74(5)
M−N−C(sp2)
M−N−C(sp3)
C(sp2)−N−C(sp3)
135.01(13)
104.28(12)
120.70(16)
135.54(15)
109.71(15)
114.42(19)
135.32(16)
109.00(17)
115.2(2)
a
Table 2. Ethylene/1-Octene Copolymerization Results
b
c
entry
catalyst
temp (°C)
yield (g)
activity
[Oct] (mol %)
Mw
Mw/Mn
Tm (°C)
1
2
8
100−103−100
100−123−113
100−125−112
100−127−116
100−135−129
100−129−125
100−133−129
100−130−114
100−134−113
100−133−113
100−141−115
100−127−114
100−132−115
100−100
0.36
1.10
1.02
1.30
2.42
1.80
2.35
1.33
0.86
1.13
1.47
1.24
1.37
∼0
7
22
20
26
48
36
47
27
17
23
29
25
27
∼0
36
3.3
2.1
3.3
3.2
4.3
3.0
3.8
7.7
2.5
3.8
3.6
3.7
3.9
119000
2.72
3.13
2.81
2.59
2.77
2.91
2.70
6.85
5.93
4.33
4.56
3.30
2.58
111
118
111
115
116
111
108
108
116
114
115
111
113
9
207000
81000
3
10
11
12
13
14
15
16
17
18
19
20
21
CGC
4
103000
70000
5
6
94000
7
76000
8
117000
250000
147000
151000
115000
83000
9
10
11
12
13
14
d
15
100−125−113
1.80
17.4
127000
2.92
114, 68
a
Polymerization conditions: methylcyclohexane solution of 1-octene (1.0 M, 30 mL), complex (1.0 μmol), [HNMe(C18H37)2]+[B(C6F5)4]− (1.2
b
c
μmol), MAO (Al/M = 125), ethylene (30 bar), 3 min. Activity in units of 106 g/mol-M·h. 1-Octene mole fraction in the copolymer measured from
d
the H NMR spectrum. Complex (1.0 μmol), [Ph3C]+[B(C6F5)4]− (4.0 μmol), and iBu3Al (0.80 mmol) were used.
1
X-ray Crystallographic Studies. Single crystals of 9, 14,
16, and 19 were grown in toluene/hexane solution in a
refrigerator, and their structures were confirmed by X-ray
crystallography (Figure 2). The metrical parameters are
summarized in Table 1. All complexes adopted a distorted
trigonal-bipyramidal structure. Two benzyl and phosphine
ligands were situated in equatorial positions, while the amido
and remaining benzyl groups occupied the apical positions. The
Hf (or Zr) atom was located on a plane formed by the three
equatorial ligands, and the sum of the bond angles of P−M−
C(eq1), C(eq1)−M−C(eq2), and C(eq2)−M−P was approx-
imately 360°. The M−C(apical) vector was almost perpendic-
ular to the plane formed by the three equatorial ligands
(C(apical)−M−C(eq1), C(apical)−M−C(eq2), and C-
(apical)−M−P angles, 82−99°). The N−M−P angles (68−
69°) were acutely deviated from the ideal angle of 90°
anticipated for the trigonal-bipyramidal structure. As a result of
this deviation, the N−M−C(apical) angles (145−153°) were
also distorted from the ideal 180°. The coordinating nitrogen
atoms adopted sp2 hybridization for π-donation, and the sum of
bond angles around the nitrogen atom was approximately 360°.
The Hf−P, Hf−N, and Hf−C bond distances were all slightly
shorter than the corresponding Zr−P, Zr−N, and Zr−C bond
distances. In all structures, the M−C(apical) distance was
longer than the M−C(equatorial) distances. The tight binding
of the benzyl ligands in the equatorial positions is thought to be
due to the partial participation of aromatic π-electrons in
bonding with the metal; in all cases, the M−C(eq)−C6 angles
were less obtuse than the M−C(apical)−C6 angle. In the
structure of 19 prepared from the sterically least encumbered
ligand, the metrical parameters around an equatorial benzyl
ligand were fairly different from those of either the remaining
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benzyl ligands in the same compound or the benzyl ligands in
the other three compounds. The M−C(eq)−C6 angle was
acute (85.5°) compared with those of the others (101−116°).
The C(eq1)−M−C(eq2) angle (134.6°) also deviated from that
observed for the other complexes (113−118°). These
parameters suggest that an η3-binding mode was adopted by
the benzyl ligand, which was further supported by the observed
distances between Zr and the benzyl carbon atoms; the Zr−
C6(ipso) and Zr−C6(ortho) distances were shorter (2.605(3)
and 2.709(3) Å, respectively) than the corresponding distances
observed for the other equatorial benzyl ligand, which adopted
an η1-binding mode (2.981(3) and 3.485(3) Å). However, in
observed at ca. 110 °C in the DSC scan, which was similar to
that of commercial linear low-density polyethylene (LLDPE).
The imine-(en)amido and quinoline-amido LMX3-type com-
plexes of Hf and Zr also showed moderate 1-octene
incorporation in a similar range.11,13,14,16
The molecular weights of the obtained polymers were found
to be sensitive to the ligand structure; the tetrahydroquinoline-
derived Hf complex 8 generated a polymer with Mw = 119 000
(Table 2, entry 1). Attaching a methyl substituent at the 2-
position of the tetrahydroquinoline framework resulted in a
nearly 2-fold increase in Mw to 207 000 (entry 2), whereas
attaching a bulkier isopropyl or n-butyl group yielded a
decrease in Mw back to ∼100 000 (entries 3−4). A similar trend
was observed for Zr complexes: the tetrahydroquinaldine-
derived Zr complex 16 generated the highest-molecular-weight
polymer (Mw = 250 000), whereas N-alkylaniline-derived
complexes generated lower-molecular-weight polymers (Mw =
70 000−115 000) than those derived from tetrahydroquinoline
derivatives in both the Hf and the Zr complexes. The molecular
weight distribution of the polymers prepared using Hf
complexes was narrow (Mw/Mn = 2.6−3.1) but was rather
broad for the Zr complexes (Mw/Mn = 2.6−6.8).
1
the H NMR spectrum of 19, only one benzyl-CH2 signal was
observed as a singlet at 2.55 ppm because of the rapid
scrambling.
Polymerization Studies. The newly prepared complexes
(8−21) were screened for activity toward ethylene/1-octene
copolymerization under identical conditions: 1-octene in
methylcyclohexane (1.0 M, 30 mL); metal complex (1.0
μmol); [HNMe(C18H37)2]+[B(C6F5)4]− (1.2 μmol); MAO
(0.125 mmol); ethylene (30 bar); initial temperature 100 °C; 3
min (Table 2). Methylcyclohexane-soluble [HNMe-
(C18H37)2]+[B(C6F5)4]− was used as an activator, and MAO
was fed as a scavenger.6 The temperature rapidly increased by
the exotherm to reach a maximum value and then dropped
slowly either by the cooling with ambient air or by catalyst
deactivation (Table 2, column 3). The polymerizations were
run for a short time because of difficulties in stirring the
reaction mixture due to the formation of a viscous solution in
such a short time. Though Hf complex 8 showed a negligible
activity (7 × 106 g/mol-M·h, entry 1), the other Hf and Zr
complexes showed fairly high activities ((17−48) × 106 g/mol-
M·h, entries 2−13); in contrast, Ti complex 21 was not active
at all. The constrained geometry catalyst (CGC) [Me2Si(η5-
Me4C5)(NtBu)]TiCl2 showed a similar activity (36 × 106 g/
mol-Ti·h) under the same temperature and pressure, but was
activated with [Ph3C]+[B(C6F5)4]− (B/Ti = 4) and iBu3Al
(A1/Ti = 800). Hf complexes 12−14 derived from N-
alkylaniline showed higher activities ((36−47) × 106 g/mol-
Hf·h, entries 5−7) than those (9−11) derived from
tetrahydroquinoline derivatives ((20−26) × 106 g/mol- Hf·h,
entries 2−4). Activities of Zr complexes were relatively
insensitive to the ligand structure, falling in the range of
(20−30) × 106 g/mol-Zr·h (entries 8−13). When 12 (1.0
μmol) was activated with just MAO (Al/Hf = 125), a negligible
amount of polymer was obtained, but some amount of polymer
(0.60 g) was generated when the MAO amount was increased
to A1/Hf = 1000. When 2 equiv of [HNMe(C18H37)2]+[B-
(C6F5)4]− was used instead of 1.2 equiv, the yield was
marginally increased from 2.42 to 2.63 g.
CONCLUSION
■
Diphenylphosphanyl groups were easily attached to either the
8-position of 2-alkyl-1,2,3,4-tetrahydroquinolines or the ortho-
position of N-alkylanilines in a one-pot procedure. Using the
resulting compounds, a series of phosphine-amido Hf and Zr
complexes were prepared, and the structures of four of these
complexes were elucidated by X-ray crystallography. The
complexes adopted a distorted trigonal-bipyramidal structure
with two benzyl ligands in the equatorial positions and the
remaining benzyl moiety occupying the apical position; only a
1
single benzyl signal was observed in the H NMR spectra of
these complexes, indicating rapid scrambling of the three benzyl
ligands in solution. In the complex coordinated by the sterically
least encumbering ligand, a benzyl in the equatorial position
adopted the η3-binding mode. The complexes exhibited
comparable activities ((17−48) × 106 g/mol-M·h) in ethyl-
ene/1-octene copolymerizations to those observed with CGC
(36 × 106 g/mol-Ti·h), even though the 1-octene incorporation
capabilities were inferior to those observed for CGC (2−8 mol
% versus 17 mol %). Tetrahydroquinaldine-derived Hf and Zr
complexes generated high-molecular-weight polymers (Mw
>
200 000) even at high reaction temperatures of 100−130 °C.
EXPERIMENTAL SECTION
■
General Remarks. All manipulations were performed under an
inert atmosphere using standard glovebox and Schlenk techniques.
Diethyl ether, THF, C6D6, and C6D5CD3 were distilled from
benzophenone ketyl. Methylcyclohexane (anhydrous grade), toluene,
and 1-octene used for the polymerization reaction were purchased
from Aldrich and purified over a Na/K alloy. Ethylene was purchased
from Conley Gas (99.0%) and was purified by contact with molecular
The 1-octene contents observed for the polymers prepared
with Hf complexes were in the range of 2.1−4.3 mol %.
Complexes 12−14 derived from N-alkylaniline showed slightly
higher 1-octene incorporation than those (9−11) derived from
tetrahydroquinoline derivatives. The tetrahydroquinoline-de-
rived Zr complex 15 showed the highest 1-octene incorporation
(7.7 mol %) among the prepared Hf and Zr complexes;
however, the other Zr complexes showed low 1-octene
incorporation (2.5−3.9 mol %), similar to that shown by the
Hf complexes. These 1-octene contents were significantly lower
than that of the polymer prepared using the CGC under similar
conditions (17 mol %, Table 2, entry 15). Because of low 1-
octene content, a single and fairly sharp melting signal was
1
sieves and copper for several days under 50 bar pressure. The H
NMR (400 MHz), 13C NMR (100 MHz), 19F NMR (376 MHz), and
31P NMR (162 MHz) spectra were recorded on a Varian Mercury plus
400. Elemental analyses were carried out at the Analytical Center,
Kyunghee University. Mass spectra were obtained on a JEOL JMS-
700. Hf(CH2Ph)4, Zr(CH2Ph)4, Ti(CH2Ph)4, and [HNMe-
(C18H37)2]+[B(C6F5)4]− were prepared according to the reported
procedure and conditions.47−49
Compound 1. n-BuLi (9.5 mL, 23.7 mmol, 2.5 M solution in
hexane) was added dropwise to a solution of 1,2,3,4-tetrahydroquino-
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line (3.00 g, 22.5 mmol) in hexane (42 mL) at room temperature. The
solution was stirred at room temperature overnight. The resultant
white solid precipitated from the solution was subsequently filtered
and washed with hexane, yielding the corresponding lithium amide
compound in quantitative yield (3.13 g). Then, CO2 gas was added to
a solution of lithium amide (0.59 g, 4.23 mmol) in diethyl ether (10
mL) stirred at −78 °C. The white solid disappeared immediately. The
temperature was raised slowly to room temperature while excess CO2
gas was removed through a bubbler. The solution was stirred
overnight, resulting in the precipitation of a white solid. THF (0.34 g,
4.7 mmol) and tBuLi (2.7 mL, 4.7 mmol, 1.7 M solution in pentane)
were added successively to the slurry at −20 °C, and the solution was
stirred for 2 h at this temperature. A solution of Ph2P(OPh) (1.00 g,
3.59 mmol) in diethyl ether (10 mL) was added to the ortho-lithiated
compound via syringe at −20 °C. The solution was subsequently
stirred for 1 h at −20 °C and warmed slowly to room temperature.
After stirring the solution overnight, H2O (10 mL) was added at 0 °C
and the mixture was stirred at room temperature for 30 min. The
product was extracted with diethyl ether (3 × 20 mL). The organic
phase was collected and dried over anhydrous MgSO4. The solvent
was removed using a rotary evaporator to obtain a residue, which was
purified using column chromatography on silica gel by eluting with
hexane and diethyl ether (v/v, 50:1). The product was obtained as a
(m, 2H, 3-quinoline), 0.69 (d, J = 7.2 Hz, 3H, CH3), 0.67 (d, J = 7.2
Hz, 3H, CH3) ppm. 13C{1H} NMR (C6D6): δ 148.20 (d, J = 17 Hz),
136.70 (d, J = 8.3 Hz), 136.46 (d, J = 8.3 Hz), 134.28 (d, J = 9.1 Hz),
134.09 (d, J = 9.1 Hz), 132.84 (d, J = 3.8 Hz), 130.73, 128.91, 128.87,
128.85, 128.78, 121.27 (d, J = 3.0 Hz), 117.93 (d, J = 6.8 Hz), 116.99
(d, J = 3.1 Hz), 57.86, 32.98, 27.61, 24.86, 18.62, 18.53 ppm. 31P{1H}
NMR (C6D6): δ −19.87 ppm. HRMS(EI): m/z calcd ([M+]
C24H26NP) 360.1880. Found: 360.1881.
Compound 4. The title compound was synthesized using the same
conditions and procedure as those for 3 using 2-n-butyl-1,2,3,4-
tetrahydroquinaline (0.80 g, 4.23 mmol). The final product was
purified by column chromatography on silica gel eluting with hexane
and ethyl acetate (v/v, 50:1). The pale yellow viscous oil was obtained
1
in 77% yield (1.04 g). H NMR (C6D6): δ 7.60−7.40 (m, 4H, PPh),
7.14−7.00 (m, 6H, PPh), 7.01−6.92 (m, 2H, 5- and 7-quinoline), 6.60
(t, J = 7.2 Hz, 1H, 6-quinoline), 5.01 (br s, 1H, NH), 3.10−2.83 (m,
1H, 2-quinoline), 2.76−2.40 (m, 2H, 4-quinoline), 1.68−1.54 (m, 1H,
3-quinoline), 1.46−1.29 (m, 1H, 3-quinoline), 1.25−0.94 (m, 6H,
CH2), 0.77 (t, J = 6.8 Hz, 3H, CH3) ppm. 13C{1H} NMR (C6D6): δ
148.07 (d, J = 18 Hz), 136.79 (d, J = 8.3 Hz), 136.51 (d, J = 8.3 Hz),
134.21 (d, J = 5.3 Hz), 134.02 (d, J = 5.3 Hz), 132.99 (d, J = 3.8 Hz),
130.93, 128.90, 128.85, 128.80, 128.79, 121.11 (d, J = 3.0 Hz), 117.74
(d, J = 6.9 Hz), 117.06 (d, J = 2.3 Hz), 52.16 (d, J = 1.5 Hz), 36.68,
28.30, 28.24, 27.35, 23.27, 14.61 ppm. 31P{1H} NMR (C6D6): δ
−20.09 ppm. HRMS(EI): m/z calcd ([M+] C25H28NP) 374.2037.
Found: 374.2038.
1
pale yellow viscous oil (0.59 g, 52%). H NMR (C6D6): δ 7.53−7.43
(m, 4H, PPh), 7.10−7.01 (m, 6H, PPh), 6.96−6.90 (m, 1H, 7-
quinoline), 6.89 (d, J = 7.2 Hz, 1H, 5-quinoline), 6.56 (t, J = 7.2 Hz,
1H, 6-quinoline), 4.95 (br s, 1H, NH), 2.80−2.70 (m, 2H, 2-
quinoline), 2.48 (t, J = 6.8 Hz, 2H, 4-quinoline), 1.53−1.42 (m, 2H, 3-
quinoline) ppm. 13C{1H} NMR (C6D6): δ 148.44 (d, J = 19 Hz),
136.81 (d, J = 8.4 Hz), 134.12 (d, J = 18 Hz), 133.01, 132.49 (d, J =
9.9 Hz), 131.15, 128.84 (d, J = 6.1 Hz), 121.08 (d, J = 3.0 Hz), 117.75
(d, J = 6.9 Hz), 117.06, 42.31, 28.14, 22.23 ppm. 31P{1H} NMR
(C6D6): δ −21.23 ppm. HRMS(EI): m/z calcd ([M+] C21H20NP)
317.1332. Found: 317.1333.
Compound 5. The title compound was synthesized using the same
conditions and procedure as those for 1 with N-methylaniline (0.45 g,
4.23 mmol). The final product was purified by column chromatog-
raphy on silica gel eluting with hexane and diethyl ether (v/v, 50:1)
1
(0.73 g, 70%). mp 117 °C. H NMR (C6D6): δ 7.50−7.35 (m, 4H,
PPh), 7.21 (t, J = 7.2 Hz, 1H), 7.07 (t, J = 6.8 Hz, 1H) 7.10−6.88 (m,
6H, PPh), 6.63 (t, J = 7.6 Hz, 1H), 6.48 (dd, J = 8.4, 5.6 Hz, 1H), 4.83
(br s, 1H, NH), 2.26 (d, J = 5.2 Hz, 3H, CH3) ppm. 13C{1H} NMR
(C6D6): δ 152.67 (d, J = 19 Hz), 136.49 (d, J = 7.6 Hz), 134.96,
134.10 (d, J = 18 Hz), 131.21, 128.91 (d, J = 3.1 Hz), 128.86, 119.05
(d, J = 7.6 Hz), 117.59, 109.91 (d, J = 3.1 Hz), 30.57 ppm. 31P{1H}
NMR (C6D6): δ −21.10 ppm. HRMS(EI): m/z calcd ([M+]
C19H18NP) 291.1176. Found: 291.1177.
Compound 2. The title compound was synthesized using the same
conditions and procedure as those for 1 using 1,2,3,4-tetrahydroqui-
naldine (0.62 g, 4.23 mmol). The final product was purified by column
chromatography on silica gel eluting with hexane and diethyl ether (v/
v, 50:1). The pale yellow viscous oil was obtained in 50% yield (0.60
1
Compound 6. The title compound was synthesized using the same
conditions and procedure as those for 1 using N-ethylaniline (0.51 g,
4.23 mmol). The final product was purified by column chromatog-
raphy on silica gel eluting with hexane and diethyl ether (v/v, 50:1)
(0.77 g, 70%). mp 71−72 °C. 1H NMR (C6D6): δ 7.57−7.37 (m, 4H,
PPh), 7.21 (dt, J = 7.2, 1.6 Hz, 1H), 7.11 (dt, J = 6.8, 1.6 Hz, 1H),
7.09−6.97 (m, 6H, PPh), 6.28 (t, J = 7.2 Hz, 1H), 6.55 (dd, J = 8.0, 5.2
Hz, 1H), 4.83 (br s, 1H, NH), 2.90−2.65 (m, 2H, NCH2), 0.78 (t, J =
7.2 Hz, 3H, CH3) ppm. 13C{1H} NMR (C6D6): δ 151.83 (d, J = 17
Hz), 136.50 (d, J = 7.6 Hz), 135.31, 134.04 (d, J = 18 Hz), 131.23,
128.89 (d, J = 4.6 Hz), 128.85, 118.96 (d, J = 7.6 Hz), 117.56, 110.59,
38.77, 14.75 ppm. 31P{1H} NMR (C6D6): δ −20.56 ppm. HRMS(EI):
m/z calcd ([M+] C20H20NP) 306.1412. Found: 306.1412.
g). H NMR (C6D6): δ 7.56−7.40 (m, 4H, PPh), 7.12−7.00 (m, 6H,
PPh), 6.99 (t, J = 7.2 Hz, 1H, 7-quinaldine), 6.93 (d, J = 7.2 Hz, 1H, 5-
quinaldine), 6.59 (t, J = 7.6 Hz, 1H, 6-quinaldine), 4.96 (br s, 1H,
NH), 3.10−2.96 (m, 1H, 2-quinaldine), 2.66−2.42 (m, 2H, 4-
quinaldine), 1.53−1.18 (m, 2H, 3-quinaldine), 0.75 (d, J = 6.4 Hz, 3H,
CH3) ppm. 13C{1H} NMR (C6D6): δ 148.41 (d, J = 18 Hz), 136.97
(d, J = 8.4 Hz), 136.61 (d, J = 8.4 Hz), 134.14 (d, J = 6.8 Hz), 133.96
(d, J = 6.8 Hz), 133.26 (d, J = 3.8 Hz), 131.03, 128.90, 128.87, 128.83,
128.80, 120.89 (d, J = 3.1 Hz), 117.51 (d, J = 6.8 Hz), 117.17, 47.78,
30.01, 27.53, 22.58 ppm. 31P{1H} NMR (C6D6): δ −20.94 ppm.
HRMS(EI): m/z calcd ([M+] C22H22NP) 331.1490. Found: 331.1490.
Compound 3. THF (10 mL) was added dropwise to a flask
containing the lithium amide (0.77 g, 4.23 mmol) at −78 °C. After
CO2 gas was added at −78 °C, the clear solution was stirred for 1 h at
−78 °C. The temperature was slowly raised to 0 °C while excess CO2
gas was removed through a bubbler. The solvent was removed by
vacuum, and then diethyl ether (10 mL) was added. After cooling to
−20 °C, THF (0.34 g, 4.7 mmol) and tBuLi (2.7 mL, 4.7 mmol, 1.7 M
solution in pentane) were added successively to the slurry at −20 °C,
and the solution was stirred for 2 h at this temperature. A solution of
Ph2P(OPh) (1.00 g, 3.59 mmol) in diethyl ether solution (10 mL) was
added to the ortho-lithiated compound via syringe at −20 °C. The
solution was subsequently stirred for 1 h at −20 °C and warmed
slowly to room temperature. The workup procedure was the same with
that of 1. The final product was purified by column chromatography
on silica gel eluting with hexane and diethyl ether (v/v, 50:1). A pale
Compound 7. The title compound was synthesized using the same
conditions and procedure as those for 3 with N-isopropylaniline (0.57
g, 4.23 mmol). The final product was purified by column
chromatography on silica gel eluting with hexane and diethyl ether
1
(v/v, 50:1) (0.55 g, 48%). mp 53−54 °C. H NMR (C6D6): δ 7.51−
7.38 (m, 4H, PPh), 7.20 (dt, J = 7.6, 1.6 Hz, 1H), 7.14 (dt, J = 6.6, 1.2
Hz, 1H), 7.11−6.99 (m, 6H, PPh), 6.67−6.56 (m, 2H), 4.75 (br s, 1H,
NH), 3.46−3.32 (m, 1H, NCH), 0.87 (d, J = 6.8 Hz, 6H, CH3) ppm.
13C{1H} NMR (C6D6): δ 150.92 (d, J = 17 Hz), 136.44 (d, J = 8.4
Hz), 135.64 (d, J = 6.1 Hz), 134.00 (d, J = 19 Hz), 131.20, 128.87 (d, J
= 4.5 Hz), 128.83, 119.10 (d, J = 7.6 Hz), 117.30 (d, J = 3.8 Hz),
111.33 (d, J = 3.0 Hz), 44.59, 22.96 ppm. 31P{1H} NMR (C6D6): δ
−19.59 ppm. HRMS(EI): m/z calcd ([M+] C21H22NP) 320.1568.
Found: 320.1568.
1
yellow solid was obtained in 77% yield (1.00 g). mp 68−69 °C. H
NMR (C6D6): δ 7.56−7.43 (m, 4H, PPh), 7.14−7.01 (m, 6H, PPh),
7.00−6.91 (m, 2H, 5- and 7-quinoline), 6.59 (t, J = 7.6 Hz, 1H, 6-
quinoline), 4.96 (br s, 1H, NH), 2.84−2.74 (m, 1H, 2-quinoline),
2.68−2.48 (m, 2H, 4-quinoline), 1.59−1.48 (m, 1H, CH), 1.48−1.29
Complex 8. Hf(CH2Ph)4 (0.42 g, 0.77 mmol) and 1 (0.25 g, 0.77
mmol) were mixed in toluene (5 mL) at −30 °C. The temperature was
raised slowly to room temperature, and the solution was stirred
overnight. After the solvent was removed under vacuum, the residue
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was triturated in hexane (∼1 mL). The yellow solid was isolated by
Complex 13. The title complex was synthesized using the same
conditions and procedure as those for 8 using 6 (0.27 g, 0.87 mmol).
It was obtained as a yellow solid in 74% yield (0.49 g). H NMR
decantation, and the residual solvent was removed by evacuation (0.47
1
1
g, 80%). H NMR (C6D6): δ 7.03−6.77 (m, 26H), 6.73 (dt, J = 7.6,
(C6D6): δ 7.20−6.77 (m, 26H), 6.72 (dt, J = 8.0, 1.6 Hz, 1H), 6.48 (t,
J = 7.2 Hz, 1H), 6.32 (dd, J = 8.4, 5.2 Hz, 1H), 3.37 (quintet, J = 6.4
Hz, 2H, NCH2), 2.36 (s, 6H, HfCH2), 0.89 (t, J = 6.4 Hz, 3H, CH3)
ppm. 13C{1H} NMR (C6D6): δ 161.26 (d, J = 25 Hz), 144.43, 133.80
(d, J = 13 Hz), 133.67, 133.26, 130.70, 129.15 (d, J = 9.1 Hz), 128.77,
128.41, 122.36, 122.32, 121.91, 119.11 (d, J = 5.3 Hz), 112.36 (d, J =
8.3 Hz), 82.67 (HfCH2), 37.02, 13.10 ppm. 31P{1H} NMR (C6D6): δ
32.95 ppm. Anal. Calcd (C41H40NPHf): C, 65.12; H, 5.33; N, 1.85.
Found: C, 64.79; H, 5.05; N, 1.62%.
1.2 Hz, 1H), 6.50 (dt, J = 7.2, 1.2 Hz, 1H), 3.49−3.38 (m, 2H, 2-
quinoline), 2.43 (t, J = 6.4 Hz, 2H, 4-quinoline), 2.37 (s, 6H, HfCH2),
1.58−1.46 (m, 2H, 3-quinoline) ppm. 13C{1H} NMR (C6D6): δ
159.66 (d, J = 27 Hz), 144.56, 133.91 (d, J = 6.9 Hz), 133.82, 131.39,
130.57, 129.69 (d, J = 30 Hz), 129.11 (d, J = 9.1 Hz), 128.83, 128.20,
123.34 (d, J = 7.6 Hz), 122.39, 120.30 (d, J = 39 Hz), 119.39 (d, J =
5.3 Hz), 83.25 (HfCH2), 44.23, 27.88, 21.56 ppm. 31P{1H} NMR
(C6D6): δ 31.03 ppm. Anal. Calcd (C42H40NPHf): C, 65.66; H, 5.25;
N, 1.82. Found: C, 65.95; H, 5.56; N, 2.14%.
Complex 14. The title complex was synthesized using the same
Complex 9. The title complex was synthesized using the same
conditions and procedure as those for 8 using 7 (0.23 g, 0.73 mmol).
conditions and procedure as those for 8 using 2 (0.24 g, 0.73 mmol).
1
1
It was obtained as a yellow solid in 80% yield (0.45 g). H NMR
It was obtained as a yellow solid in 82% yield (0.47 g). H NMR
(C6D6): δ 7.30−6.80 (m, 28H), 6.57 (t, J = 7.6 Hz, 1H), 4.18−4.05
(m, 1H, NCH), 2.34 (s, 6H, HfCH2), 1.28 (d, J = 6.4 Hz, 6H, CH3)
ppm. 13C{1H} NMR (C6D6): δ 158.76 (d, J = 24 Hz), 145.28, 134.09
(d, J = 13 Hz), 133.86, 132.97, 130.69, 129.15 (d, J = 9.1 Hz), 128.90,
128.36, 123.34, 122.95, 122.40, 119.93 (d, J = 5.3 Hz), 116.21 (d, J =
6.8 Hz), 81.90 (HfCH2), 44.40, 20.96 ppm. 31P{1H} NMR (C6D6): δ
29.74 ppm. Anal. Calcd (C42H42NPHf): C, 65.49; H, 5.50; N, 1.82.
Found: C, 65.20; H, 5.28; N, 1.51%.
(C6D6): δ 7.14−6.72 (m, 26H), 6.63 (dt, J = 7.2, 1.2 Hz, 1H), 6.51
(dt, J = 7.2, 1.6 Hz, 1H), 4.18−4.06 (m, 1H, 2-quinaldine), 2.76−2.58
(m, 1H, 4-quinaldine), 2.50 (dd, J = 11.6, 2.4 Hz, 3H, HfCH2), 2.41−
2.29 (m, 1H, 4-quinaldine), 2.20 (d, J = 11.6 Hz, 3H, HfCH2), 1.89−
1.76 (m, 1H, 3-quinaldine), 1.53−1.44 (m, 1H, 3-quinaldine), 0.91 (d,
J = 6.0 Hz, 3H, CH3) ppm. 13C{1H} NMR (C6D6): δ 157.85 (d, J = 25
Hz), 144.71, 134.55 (d, J = 13 Hz), 133.59, 133.27 (d, J = 12 Hz),
131.06, 130.64, 129.55, 129.25 (d, J = 8.3 Hz), 128.96, 128.89, 128.49,
122.44, 122.38, 122.05, 121.60 (d, J = 9.1 Hz), 119.38 (d, J = 6.0 Hz),
82.79 (d, J = 3.8 Hz, HfCH2), 44.83, 25.27, 22.31, 19.59 ppm. 31P{1H}
NMR (C6D6): δ 33.86 ppm. Anal. Calcd (C43H42NPHf): C, 66.02; H,
5.41; N, 1.79. Found: C, 66.35; H, 5.70; N, 2.12%.
Complex 15. The title complex was synthesized using the same
conditions and procedure as those for 8 using 1 (0.15 g, 0.48 mmol)
and Zr(CH2Ph)4 (0.22 g, 0.48 mmol) instead of Hf(CH2Ph)4. It was
1
obtained as a yellow solid in 61% yield (0.20 g). H NMR (C6D6): δ
7.20−6.75 (m, 26H), 6.80 (t, J = 7.6 Hz, 1H), 6.55 (dt, J = 7.2 Hz, 1.6
Hz, 1H), 3.33−3.20 (m, 2H, 2-quinoline), 2.53 (d, J = 1.6 Hz, 6H,
HfCH2), 2.43 (t, J = 6.4 Hz, 2H, 4-quinoline), 1.54−1.43 (m, 2H, 3-
quinoline) ppm. 13C{1H} NMR (C6D6): δ 158.66 (d, J = 28 Hz),
144.40, 133.91 (d, J = 12 Hz), 133.72, 131.31, 130.50, 129.85 (d, J =
28 Hz), 129.33, 129.07 (d, J = 9.1 Hz), 128.01, 122.38, 122.22 (d, J =
9.1 Hz), 120.53 (d, J = 38 Hz), 119.47 (d, J = 5.3 Hz), 72.71 (ZrCH2),
45.46, 27.96, 21.71 ppm. 31P{1H} NMR (C6D6): δ 23.44 ppm. Anal.
Calcd (C42H40NPZr): C, 74.08; H, 5.92; N, 2.06. Found: C, 74.43; H,
6.15; N, 1.78%.
Complex 10. The title complex was synthesized using the same
conditions and procedure as those for 8 using 3 (0.12 g, 0.33 mmol).
1
It was obtained as a yellow solid in 74% yield (0.20 g). H NMR
(C6D6): δ 7.15−6.75 (m, 26H), 6.62 (t, J = 7.6 Hz, 1H), 6.52 (t, J =
7.6 Hz, 1H), 3.79 (d, J = 9.2 Hz, 1H, 2-quinoline), 2.64−2.44 (m, 4H,
HfCH2 and 4-quinoline), 2.42−2.22 (m, 4H, HfCH2 and 4-quinoline),
1.91−1.77 (m, 2H, 3-quinoline), 1.60−1.45 (m, 1H, CHCH3), 0.73 (d,
J = 6.4 Hz, 3H, CH3), 0.40 (d, J = 6.4 Hz, 3H, CH3) ppm. 13C{1H}
NMR (C6D6): δ 156.73 (d, J = 24 Hz), 144.65, 134.44 (d, J = 12 Hz),
133.63 (d, J = 12 Hz), 131.44, 131.00 (d, J = 27 Hz), 130.66, 130.59,
130.46, 130.21, 129.15 (d, J = 8.4 Hz), 128.89, 128.71, 123.48 (d, J =
7.6 Hz), 122.62, 122.06, 121.70, 119.75 (d, J = 5.3 Hz), 84.07
(HfCH2), 55.20, 30.23, 23.21, 22.77, 20.78, 19.76 ppm. 31P{1H} NMR
(C6D6): δ 19.11 ppm. Anal. Calcd (C45H46NPHf): C, 66.70; H, 5.72;
N, 1.73. Found: C, 66.47; H, 5.46; N, 1.98%.
Complex 16. The title complex was synthesized using the same
conditions and procedure as those for 15 using 2 (0.17 g, 0.50 mmol).
1
It was obtained as a yellow solid in 82% yield (0.28 g). H NMR
(C6D6): δ 7.14−6.77 (m, 26H), 6.67 (t, J = 7.2 Hz, 1H), 6.55 (dt, J =
7.2, 1.6 Hz, 1H), 3.91−3.82 (m, 1H, 2-quinaldine), 2.72−2.50 (m, 4H,
HfCH2 and 4-quinaldine), 2.46−2.26 (m, 4H, HfCH2 and 4-
quinaldine), 1.79−1.66 (m, 1H, 3-quinaldine), 1.46−1.34 (m, 1H, 3-
quinaldine), 0.91 (d, J = 6.0 Hz, 3H, CH3) ppm. 13C{1H} NMR
(C6D6): δ 156.96 (d, J = 27 Hz), 144.44, 134.56 (d, J = 13 Hz), 133.34
(d, J = 12 Hz), 131.00, 130.56, 129.68, 129.31, 129.13 (d, J = 8.4 Hz),
128.90 (d, J = 9.8 Hz), 127.34, 122.83, 122.42, 122.33, 120.42 (d, J =
9.1 Hz), 119.39 (d, J = 5.3 Hz), 72.42 (ZrCH2), 45.56, 25.18, 22.27,
19.88 ppm. 31P{1H} NMR (C6D6): δ 25.65 ppm. Anal. Calcd
(C43H42NPZr): C, 74.31; H, 6.09; N, 2.02. Found: C, 74.53; H, 6.40;
N, 2.35%.
Complex 11. The title complex was synthesized using the same
conditions and procedure as those for 8 using 4 (0.20 g, 0.54 mmol).
1
It was obtained as a yellow solid in 71% yield (0.31 g). H NMR
(C6D6): δ 7.15−6.73 (m, 26H), 6.62 (t, J = 7.2, 1H), 6.51 (dt, J = 7.2
Hz, 1H), 4.01 (br s, 1H, 2-quinoline), 2.74−2.57 (m, 1H, 4-quinoline),
2.53 (dd, J = 11.6, 2.4 Hz, 3H, HfCH2), 2.44−2.30 (m, 1H, 4-
quinoline), 2.23 (d, J = 11.6 Hz, 3H, HfCH2), 1.94−1.71 (m, 2H, 3-
quinoline), 1.60−1.00 (m, 6H, CH2), 0.81 (t, J = 7.2 Hz, 3H, CH3)
ppm. 13C{1H} NMR (C6D6): δ 158.18 (d, J = 25 Hz), 144.79, 134.50
(d, J = 12 Hz), 133.57, 133.35 (d, J = 12 Hz), 131.13, 130.60 (d, J =
9.0 Hz), 129.83, 129.50, 129.21 (d, J = 8.4 Hz), 128.94, 128.86,
128.52, 122.42, 122.28, 122.11 (d, J = 8.4 Hz), 121.87, 119.42 (d, J =
6.0 Hz), 83.33 (HfCH2), 49.68, 33.35, 28.81, 23.64, 22.29, 22.02,
14.64 ppm. 31P{1H} NMR (C6D6): δ 31.98 ppm. Anal. Calcd
(C46H48NPHf): C, 67.02; H, 5.87; N, 1.70. Found: C, 67.33; H, 5.56;
N, 2.03%.
Complex 17. The title complex was synthesized using the same
conditions and procedure as those for 15 using 3 (0.15 g, 0.42 mmol).
The reaction time was 3 days. It was obtained as a yellow solid in 63%
1
yield (0.19 g). H NMR (C6D6): δ 7.15−6.87 (m, 24H), 6.75−6.66
(m, 2H), 6.62 (t, J = 7.2 Hz, 1H), 6.53 (dt, J = 7.2, 1.6 Hz, 1H), 3.78−
3.62 (m, 1H, 2-quinoline), 2.81 (dd, J = 10.4, 3.2 Hz, 3H, HfCH2),
2.64−2.41 (m, 4H, HfCH2 and 4-quinoline), 2.41−2.26 (m, 1H, 4-
quinoline), 1.92−1.72 (m, 2H, 3-quinoline), 1.68−1.48 (m, 1H,
CHCH3), 0.76 (d, J = 6.4 Hz, 3H, CH3), 0.43 (d, J = 6.4 Hz, 3H, CH3)
ppm. 13C{1H} NMR (C6D6): δ 156.85 (d, J = 27 Hz), 144.42, 134.26
(d, J = 12 Hz), 133.86 (d, J = 13 Hz), 133.37, 131.41, 131.06, 130.69,
130.40, 130.10, 129.21, 128.75 (d, J = 9.0 Hz), 128.61, 122.69, 122.48,
122.32, 122.05 (d, J = 9.0 Hz), 119.56 (d, J = 5.3 Hz), 74.85 (ZrCH2),
55.97, 55.92, 30.67, 22.76, 20.53, 19.92 ppm. 31P{1H} NMR (C6D6): δ
16.60 ppm. Anal. Calcd (C45H46NPZr): C, 74.75; H, 6.41; N, 1.94.
Found: C, 74.97; H, 6.19; N, 2.25%.
Complex 12. The title complex was synthesized using the same
conditions and procedure as those for 8 using 5 (0.19 g, 0.65 mmol).
1
It was obtained as a yellow solid in 73% yield (0.35 g). H NMR
(C6D6): δ 7.20 (t, J = 6.8 Hz, 1H), 7.20−6.60 (m, 26H), 6.53 (t, J =
7.2 Hz, 1H), 6.34 (dd, J = 8.0, 5.2 Hz, 1H), 2.80 (s, 3H, CH3), 2.40 (s,
6H, HfCH2) ppm. 13C{1H} NMR (C6D6): δ 163.45 (d, J = 27 Hz),
144.09, 133.77 (d, J = 13 Hz), 133.60, 130.58, 129.65, 129.13 (d, J =
9.8 Hz), 128.79, 128.24, 122.49, 120.87, 120.48, 119.37 (d, J = 5.3
Hz), 111.84 (d, J = 9.1 Hz), 83.30 (HfCH2), 32.63 ppm. 31P{1H}
NMR (C6D6): δ 30.16 ppm. Anal. Calcd (C40H38NPHf): C, 64.73; H,
5.16; N, 1.89. Found: C, 64.55; H, 4.84; N, 1.62%.
Complex 18. The title complex was synthesized using the same
conditions and procedure as those for 15 using 4 (0.14 g, 0.38 mmol).
7363
dx.doi.org/10.1021/om400899g | Organometallics 2013, 32, 7357−7365

Organometallics
Article
1
It was obtained as a yellow solid in 76% yield (0.22 g). H NMR
(C6D6): δ 7.15−6.75 (m, 26H), 6.66 (t, J = 7.2 Hz, 1H), 6.55 (dt, J =
7.2, 1.6 Hz, 1H), 3.86−3.72 (m, 1H, 2-quinoline), 2.68 (dd, J = 10.4,
2.4 Hz, 3H, HfCH2), 2.64−2.49 (m, 1H, 4-quinoline), 2.41 (dd, J =
10.4, 2.4 Hz, 3H, HfCH2), 2.38−2.22 (m, 1H, 4-quinoline), 1.84−1.67
(m, 2H, CH2, 3-quinoline), 1.58−1.01 (m, 6H, CH2), 0.80 (t, J = 6.8,
3H, CH3) ppm. 13C{1H} NMR (C6D6): δ 157.44 (d, J = 27 Hz),
144.52, 134.49 (d, J = 13 Hz), 133.42 (d, J = 12 Hz), 133.40, 131.07,
130.53 (d, J = 16 Hz), 129.98, 129.66, 129.29, 129.12 (d, J = 8.4 Hz),
128.87 (d, J = 9.9 Hz), 128.34, 122.68, 122.35, 122.25, 120.92 (d, J =
9.1 Hz), 119.40 (d, J = 5.3 Hz), 73.08 (ZrCH2), 50.53, 33.36, 28.69,
23.61, 22.28, 21.88, 14.64 ppm. 31P{1H} NMR (C6D6): δ 24.45 ppm.
Anal. Calcd (C46H48NPZr): C, 74.96; H, 6.56; N, 1.90. Found: C,
75.26; H, 6.64; N, 2.11%.
−164.2 (t, J = 21 Hz, 1F, p-C6F5), −166.9 (t, J = 19 Hz, 2F, m-C6F5)
ppm. 31P{1H} NMR: δ 28.79 ppm.
Ethylene/1-Octene Copolymerization. In a glovebox, a dried 75
mL bomb reactor was charged with a solution of 1-octene (4.0 g, 1.0
M) in methylcyclohexane (27 mL) and MMAO-4 (Akzo, 7.0 wt % Al
in toluene, 29 mg, Al/M = 75). The reactor was assembled and
brought out from the glovebox. The reactor was then heated to 100 °C
using a mantle. [HNMe(C18H37)2]+[B(C6F5)4]− (1.00 g) and 10 mg
of the complex were dissolved, respectively, in 22.3 and 1.99 g of
toluene to make stock solutions. The stock solution of [HNMe-
(C18H37)2]+[B(C6F5)4]− (34 mg, 1.2 μmol) was taken and diluted with
toluene to be 1.0 mL. MMAO-4 solution (19 mg, Al/M = 50) was
taken and diluted with toluene to be 1.0 mL. The stock solution of the
complex (1.0 μmol) was taken and also diluted with toluene to be 1.0
mL. The three solutions were mixed and injected into the reactor via
syringe. Ethylene gas (30 bar) was fed immediately into the reaction
vessel. The mantle was removed immediately, after injecting ethylene
gas, to allow the generated heat to dissipate. After conducting
polymerization for 3 min, the ethylene gas was vented and methanol
(10 mL) was added immediately. The isolated polymer lump or
powder was dried under vacuum at 150 °C for several hours. The 1-
Complex 19. The title complex was synthesized using the same
conditions and procedure as those for 15 using 5 (0.12 g, 0.42 mmol).
1
It was obtained as a yellow solid in 76% yield (0.21 g). H NMR
(C6D6): δ 7.20 (t, J = 7.2 Hz, 1H), 7.14−6.78 (m, 26H), 6.59 (t, J =
7.2 Hz, 1H), 6.32 (dd, J = 8.0, 5.2 Hz, 1H), 2.67 (s, 3H, CH3), 2.55 (d,
J = 2.0 Hz, 6H, HfCH2) ppm. 13C{1H} NMR (C6D6): δ 162.32 (d, J =
28 Hz), 143.98, 133.81 (d, J = 12 Hz), 133.54 (d, J = 6.9 Hz), 130.52,
129.78, 129.49, 129.33, 129.10 (d, J = 9.0 Hz), 122.46, 121.11, 120.74,
119.50 (d, J = 5.3 Hz), 110.84 (d, J = 9.1 Hz), 72.50 (ZrCH2), 33.94
(d, J = 6.1 Hz) ppm. 31P{1H} NMR (C6D6): δ 22.46 ppm. Anal. Calcd
(C40H38NPZr): C, 73.36; H, 5.85; N, 2.14. Found: C, 73.05; H, 5.66;
N, 2.42%.
1
octene contents were calculated by the analysis of the copolymer H
NMR spectra; the methyl (CH3) signals (0.93−1.02 ppm) were well
isolated from the methine (CH) and methylene (CH2) signals (1.30−
1.50 ppm), allowing for the 1-octene content to be calculated from the
integration values of the two regions. The copolymer (10 mg) was
1
dissolved in C6D5CD3, and the H NMR spectra were recorded at 80
Complex 20. The title complex was synthesized using the same
°C. For the polymerization with CGC (Table 2, entry 15), the
activated catalyst, which was prepared by mixing CGC (1.0 μmol),
[C(C6H5)3]+[B(C6F5)4]− (4.0 μmol), and (iBu)3Al (0.80 mmol, Al/M
= 800) in toluene (3 mL), was fed to the reactor just containing a
solution of 1-octene (4.0 g, 1.0 M) in methylcyclohexane (27 mL)
without MAO at 100 °C.33,34
conditions and procedure as those for 15 using 6 (0.10 g, 0.32 mmol).
It was obtained as a yellow solid in 69% yield (0.15 g). H NMR
1
(C6D6): δ 7.15−6.82 (m, 26H), 6.77 (dt, J = 7.8, 1.2 Hz, 1H), 6.52 (t,
J = 7.2 Hz, 1H), 6.26 (dd, J = 8.0, 5.2 Hz, 1H), 3.11 (quintet, J = 6.4
Hz, 2H, NCH2), 2.51 (d, J = 2.0 Hz, 6H, HfCH2), 0.91 (t, J = 6.4 Hz,
3H, CH3) ppm. 13C{1H} NMR (C6D6): δ 160.24 (d, J = 27 Hz),
144.24, 133.85 (d, J = 12 Hz), 133.51, 133.06, 130.61, 129.25, 129.08
(d, J = 9.0 Hz), 128.66, 128.16, 122.72, 122.30, 119.18 (d, J = 5.4 Hz),
111.18 (d, J = 9.0 Hz), 72.26 (ZrCH2), 37.79, 13.48 ppm. 31P{1H}
NMR (C6D6): δ 24.65 ppm. Anal. Calcd(C41H40NPZr): C, 73.61; H,
6.03; N, 2.09. Found: C, 73.93; H, 6.23; N, 1.75%.
Complex 21. The title complex was synthesized using the same
conditions and procedure as those for 8 using 1 (0.10 g, 0.29 mmol)
and Ti(CH2Ph)4 (0.12 g, 0.29 mmol) instead of Hf(CH2Ph)4. It was
obtained as a dark brown solid in 77% yield (0.14 g). 1H NMR
(C6D6): δ 7.05−6.74 (m, 26H), 6.66 (t, J = 7.6 Hz, 1H), 6.55 (dt, J =
7.2, 1.6 Hz, 1H), 3.97−3.80 (m, 2H, 2-quinoline), 3.54 (d, J = 2.4 Hz,
6H, HfCH2), 2.40 (t, J = 6.4 Hz, 2H, 4-quinoline), 1.60−1.43 (m, 2H,
3-quinoline) ppm. 13C{1H} NMR (C6D6): δ 159.27 (d, J = 29 Hz),
148.04, 133.79 (d, J = 13 Hz), 133.73, 131.37, 130.49, 129.98 (d, J =
28 Hz), 128.99 (d, J = 9.1 Hz), 128.60, 127.75, 122.67 (d, J = 38 Hz),
122.31, 121.20 (d, J = 9.1 Hz), 120.63 (d, J = 5.3 Hz), 93.61 (TiCH2),
49.34, 27.82, 21.66 ppm. 31P{1H} NMR (C6D6): δ 28.90 ppm. Anal.
Calcd (C42H40NPTi): C, 79.12; H, 6.32; N, 2.20. Found: C, 78.95; H,
6.66; N, 2.50%.
X-ray Crystallography. Reflection data for 9, 14, 16, and 19 were
collected at 100 K on a Bruker APEX II CCD area diffractometer using
́
graphite-monochromated Mo K-α radiation (λ = 0.7107 Å).
Specimens of suitable quality and size were selected, mounted, and
centered in the X-ray beam by using a video camera. The hemisphere
of the reflection data was collected as φ and ω scan frames at 0.5°/
frame and an exposure time of 10 s/frame. The cell parameters were
determined and refined by the SMART program. Data reduction was
performed using the SAINT software. The data were corrected for
Lorentz and polarization effects. An empirical absorption correction
was applied using the SADABS program. The structures of the
compounds were solved by direct methods and refined by full-matrix
least-squares methods using the SHELXTL program package with
anisotropic thermal parameters for all non-hydrogen atoms. Further
details are listed in the Supporting Information.
ASSOCIATED CONTENT
■
S
* Supporting Information
The CIF files; crystal data and structure refinement for 9, 14,
Complex 22. B(C6F5)3 (14 mg, 0.03 mmol) was added to a
solution of 8 (21 mg, 0.030 mmol) in C6D6 (0.4 mL). An oily
compound was deposited, which was soluble by the addition of
C6H5Cl (0.2 mL). The compound was not isolated due to its
1
16, and 19; and H NMR spectra for metal complexes. This
material is available free of charge via the Internet at http://
pubs.acs.org.
1
instability. H NMR: δ 7.40−6.54 (m, 28H), 5.75 (d, JP−H = 7.2 Hz,
4H, HfCH2), 3.52 (s, 2H, PhCH2B(C6F5)3), 2.31 (t, J = 6.4 Hz, 2H, 4-
quinoline), 2.28−2.20 (m, 2H, 2-quinoline), 1.32−1.16 (m, 2H, 3-
quinoline) ppm. 19F NMR: δ −130.6 (d, J = 22 Hz, 2F, o-C6F5),
−164.1 (t, J = 21 Hz, 1F, p-C6F5), −166.9 (t, J = 18 Hz, 2F, m-C6F5)
ppm. 31P{1H} NMR: δ 26.87 ppm.
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: bunyeoul@ajou.ac.kr. Tel: 82-31-219-1844.
Notes
Complex 23. The solution for NMR studies was prepared using
The authors declare no competing financial interests.
the same conditions and procedure as those for 22 using 11 (30 mg,
1
0.04 mmol). H NMR: δ 7.40−6.40 (m, 28H), 6.07−5.92 (br, 2H,
HfCH2), 5.83−5.66 (br, 2H, HfCH2), 3.54 (s, 2H, PhCH2B(C6F5)3),
3.10−3.00 (br, 1H, 2-quinoline), 2.60−2.31 (m, 1H, 4-quinoline),
2.31−2.16 (m, 1H, 4-quinoline), 2.13−1.94 (m, 2H, 3-quinoline),
1.59−1.44 (m, 1H, CH2), 1.20−0.79 (m, 5H, CH2), 0.74 (t, J = 7.2
Hz, 3H, CH3) ppm. 19F NMR: δ −130.4 (d, J = 21 Hz, 2F, o-C6F5),
ACKNOWLEDGMENTS
■
This work was supported by the Midcarrier Researcher
Program (No. 2012-003303) and by the Basic Science Research
Program (No. 2009-0093826) through the National Research
7364
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