o-Trityl phenoxy-imino vanadium (III) complexes: synthesis, characterization, and catalysis on ethylene (co)polymerization

Article abstract of DOI:10.1002/aoc.5809

Several phenoxy-imine ligands bearing o-trityl group in phenoxy moiety RN=CHArOH (Ar = C₆H₂(CPh₃)^tBu, R = 2,6-Me₂C₆H₃ (L₁H); 2,6-ⁱPr₂C₆

Full text of DOI:10.1002/aoc.5809

Received: 25 February 2020
DOI: 10.1002/aoc.5809
Revised: 2 April 2020
Accepted: 27 April 2020
F U L L P A P E R
o-Trityl phenoxy-imino vanadium (III) complexes:
synthesis, characterization, and catalysis on ethylene (co)
polymerization
Zhiqiang Hao1,2
| Feng Li1 | Wei Gao1
1College of Chemistry, Jilin University,
Changchun, 130012, China
2Hebei Key Laboratory of Organic
Functional Molecules, College of
Chemistry & Material Science, Hebei
Normal University, Shijiazhuang, 050024,
China
Several phenoxy-imine ligands bearing o-trityl group in phenoxy moiety
RN=CHArOH (Ar = C6H2(CPh3)tBu, R = 2,6-Me2C6H3 (L1H); 2,6-iPr2C6H3
(L2H); 3,5-(CF3)2C6H3 (L3H); 3,5-(OMe)2C6H3 (L4H); CHPh2 (L5H); CPh3
(L6H)) were synthesized and characterized by1H NMR and 13C NMR spectros-
copy. The vanadium complexes based on these ligands LVCl2(THF)2 (1–6)
were synthesized via conventional transmetalation reaction in moderate to
high yields. Complexes 1–6 were fully characterized by FT-IR, elemental ana-
lyses and the molecular structures of 1, 2·H2O, (2·H2O)2(μ-Cl)2, 4, and 5 were
confirmed by X-ray crystallographic analysis in which the six-coordinated
vanadium centers are in a typical octahedral geometry. Upon activation with
Et2AlCl in toluene, complexes 1–6 showed high activities in ethylene polymeri-
Correspondence
Wei Gao, College of Chemistry, Jilin
University, Changchun 130012, China.
Email: gw@jlu.edu.cn
Funding information
National Natural Science Foundation of
China, Grant/Award Numbers: 21574052,
21603082, 51673078, U1462111
zation
affording
polymers
with
moderate
molecular
weight
(5.9–11.8 × 104 Da). Moreover, in hexane or CH2Cl2, 1–6/Et2AlCl exhibited
enhanced activities. When activated with MAO or MMAO in toluene, these
complexes showed relatively low activities but afforded polymers with ultra-
high molecular weight (up to 3.30 × 106 Da). 1–6/Et2AlCl also showed high
activities in ethylene/1-hexene copolymerization at room temperature giving
moderate molecular-weight polymers (6.5–11.4 × 104 Da) with co-monomer
incorporation being of 6.0 ꢀ 7.8%.
K E Y W O R D S
copolymerization, ethylene polymerization, ultra-high molecular weight, vanadium complexes
1 | INTRODUCTION
efforts have been devoted in design and synthesis of new
vanadium catalysts directed toward controlled polymeri-
In the early 1960s, Ziegler-type vanadium catalyst sys-
tems, which were composed of vanadium complexes such
as V (acac)3 and VOCl3, and organometallic reagents
such as EtAlCl2 and Et2AlCl, were widely explored as
homogeneous catalysts for olefin polymerization.[1] These
catalytic systems showed encouraging activities for syn-
thesis of high molecular weight polymers with narrow
polydispersity and good performance in co- and ter-
polymerization of ethylene.[1,2] Since then tremendous
zation. Various bidentate or polydentate ligands were
incorporated to the systems and it is well accepted that
the ancillary ligand which can render the metal centers
tunable electronic or steric effects plays an important role
in the catalytic performance.[3–7] Of the numerous
ligands used to support the vanadium complexes the
phenoxy-imine (FI) derivatives, which have achieved
great success in supporting group 4 complexes for olefin
polymerization, have received great attention due to their
Appl Organomet Chem. 2020;e5809.
wileyonlinelibrary.com/journal/aoc
© 2020 John Wiley & Sons, Ltd.
1 of 11
https://doi.org/10.1002/aoc.5809

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HAO ET AL.
feasible tuning of electronic and steric effects by changing
the groups in phenoxy and/or imine moiety.[6f,8] For
example, Fujita et al. have reported the bisligated vana-
dium (III) complexes with α phenoxy-imine ligands,
which exhibited high activities in ethylene polymeriza-
tion at 1 atm ethylene (A in chart 1).[3b] Li and coworkers
showed that the vanadium (III) complexes bearing FI
ligands, upon activation with Et2AlCl, exhibited high
activities for ethylene polymerization giving polymers
with moderate molecular weight.[4a,f] Such catalytic sys-
tem can also catalyze ethylene/1-hexene copolymeriza-
tion producing polymers with low co-monomer
incorporation and low molecular weights. Moreover, the
vanadium complexes with FI ligands containing hetero-
atom exhibited slightly lower activities when compared
to those with heteroatom-free ligands.[4b] The vanadyl
complexes bearing bidentate FI ligands, reported by
Nomura, showed relatively lower activities affording
polymers with broadened PDI.[5e]
Nevertheless, Li and co-workers reported that FI vana-
dium chlorides with o-tBu exhibited much lower catalytic
activities when compared to those with o-H (C in chart
1). The author declared that the o-tBu group in the ligand
may suppress the chain propagation during the
polymerization.[4a]
As part of our ongoing investigation in developing
excellent vanadium catalysts for olefin polymerization,
we are very interested in the vanadium complexes with
ortho trityl FI ligands (see in chart 1). We envisioned that
the rotation of the propeller-shape trityl moiety may fur-
nish more efficient protection to the vanadium center. To
this end, we herein report a series of o-trityl phenoxy-
imine ligands (L1H–L6H) and their vanadium com-
plexes. The catalytic performance of these complexes in
ethylene polymerization and ethylene/1-hexene copoly-
merization are also presented.
In the FI-based group 4 systems, it is well established
that the ortho group in phenoxyl moieties have a strong
impact on the behaviors in olefin polymerizations.[8] For
example, the FI-Ti and FI-Zr complexes with o-tBu
substituted ligands are usually more active than those
with o-H substituted ligands respectively.[8–10] Fujita
disclosed that the FI-Ti catalysts bearing a cycloalkyl or
o-phenyl group in ortho position produced high
molecular-weight polymers with high catalyst efficiency
and high α-olefin incorporation.[11] DFT calculations rev-
ealed that the rotation of the o-phenyl group may evade
the steric congestion during the polymerization.[11]
Despite extensive studies on the ortho-effects in FI group
4 systems, such effects in FI-Vanadium systems were less
investigated and some limited reports gave inconsistent
results. For example Nomura et al. demonstrated that, in
the arylmido vanadium(V) complexes bearing FI ligands
(B in chart 1), the size of ortho substitutes showed strong
positive effects on the activities of ethylene poly-
merization.[5e] Redshaw et al. demonstrated that the
bridged mononuclear or dinuclear FI-V complexes with
o-tBu group are more active than those without.[6d]
2 | RESULTS AND DISCUSSION
2.1 | Synthesis and characterization of
ligands L1H–L6H
The ortho-trityl FI ligands were synthesized according to
the procedure described in Scheme 1. 4-tert-butyl-
2-tritylphenol and 3-trityl-5-tert-butyl-salicylaldehyde
were synthesized according to a procedure in the litera-
1
ture and identified by H NMR and 13C NMR.[12] Con-
densation reactions of 3-trityl-5-tert-butyl-salicylaldehyde
with
corresponding
aniline
afforded
the
deriva-
2-triphenylmethyl-4-tert-butylsalicylaldiminato
tives (L1H − L6H) respectively in high yields (Scheme 1).
The ligands were characterized by 1H NMR and 13C
NMR, in which the diagnostic resonances for the imino
HC=NAr were observed at 7.88–8.65 ppm. The sharp sin-
glet at 12.63–13.94 ppm can be assigned to the OH group
which linked to the imine nitrogen atoms via a hydrogen
bond. The molecular structure of L6H (Figure 1)
established by X-ray diffraction analysis confirmed the
coordinating potential of the ligand with the O atom and
CHART 1 Typical FI vanadium complexes

HAO ET AL.
3 of 11
SCHEME 1 Synthetic routine for the ligands L1H-L6H
FIGURE 1 Perspective view of L6H with thermal ellipsoids
drawn at 30% probability level. Hydrogens solvent are omitted for
clarity. The selected bond lengths (Å): C(1)–O(1) 1.9630(18),
C(7)– N(1) 2.066(2)
SCHEME 2 Synthesis of FI vanadium complexes 1–6 and the
structures of complexes 7–8
All the complexes showed broadened and informative
1
N atom linked by an intramolecular hydrogen bond. Two
phenyl rings of the o-trityl group formed a V-shape shield
surrounding the phenoxyl group.
resonances in H{13C}NMR spectra indicating their para-
magnetic nature. The efficient magnetic moments (μeff)
of 1–6 determined by Evans method[13] are in the range
of 2.63–2.82 μB which are typical for a d2 V (III) in high-
spin state.[4c,6d,14] The molecular structures of 1, 2·H2O,
(2·H2O)2(μ-Cl)2, 4, and 5 were further determined by
X-ray crystallographic analysis and the summary of the
crystal data and the structure determination results was
listed in Table S1. Crystals of 1 suitable for X-ray crystal-
lography were grown from THF/hexane mixed solution.
The solid-state structure of 1 is shown in Figure 2 along
with the selected bond lengths and angles in the caption.
Complex 1 features a distorted octahedral geometry
around the vanadium metal center which is coordinated
by o-trityl FI ligand, two chlorine atoms, and two THF
molecules. The bond distances of V1–O1 (1.919(6) Å) and
V1–N1 (2.141(7) Å) are slightly longer than those respec-
tively in [RN=CHArO]VCl2(THF)2 probably due to the
repulsion of the trityl groups.[4a] The two chlorine atoms
and the two THF molecules in 1 are situated in cis posi-
tion respectively as evidenced by the small Cl(1)–V(1)–
2.2 | Synthesis and characterization of
vanadium complexes
The vanadium complexes (1–6) with the ortho trityl FI
ligands were synthesized via a lithium-salt metathesis
reaction (Scheme 2). Treatment of the ligands (L1H-L6H)
with nBuLi at −78 ꢁC afforded corresponding ligand
ꢁ
lithium salts as yellow solutions. After warm to −40 C,
1 equiv of VCl3(THF)3 was added in one portion giving a
red to brown solution. Evaporation of the solvent to
dryness and crystallization of the residue with
hexane/dichloromethane mixed solvent gave the vana-
dium complexes as dark red powders in moderate to high
yields. Complexes 7 and 8 was also synthesized according
to the literature for comparative studies.[4a] Complexes
1–6 were characterized by FT-IR and elemental analyses.

4 of 11
HAO ET AL.
center. The aryl ring in imino moiety of 1 is almost per-
pendicular to the phenoxyl ring (dihedral angle of
91.75ꢁ). Attempts to grow the crystals of complex 2 in
THF/hexane solution gave a hydrate complex 2·H2O (see
in Figure 3), in which one of the THF molecule was rep-
laced by a H2O molecule from the solvent. The coordina-
tion of water molecule implies the good tolerance of the
FI vanadium complexes to water. In 2·H2O the two chlo-
rine atoms situate in trans position with the Cl(1)–V(1)–
Cl(2) angle being of 170.90(5)ꢁ. The THF is in the trans
position to the nitrogen atom in imine group. The metri-
cal parameters of 2·H2O are very similar to those in 1. It
is worth to note that the vanadium atom deviates greatly
from the FI coordination plane with a deviation of
0.269 Å probably due to the repulsion of the isopropyl
groups in the imine moiety. The crystals grown in
dichloromethane solution of 2 gave out a THF-free
dimeric complex {2·H2O}2(μ-Cl) in which two
FIGURE 2 Perspective view of 1 with thermal ellipsoids
drawn at 30% probability level. Hydrogens are omitted for clarity.
The selected bond lengths (Å) and angles (deg.): V(1)–O(1) 1.919(6),
V(1)–O(2) 2.170(7), V(1)–O(3) 2.120(7), V(1)–N(1) 2.141(7),
V(1)– Cl(1) 2.330(3), V(1)–Cl(2) 2.273(3); Cl(1)–V(1)–
Cl(2) 95.57(15), N(1)–V(1)–O(1) 87.9(3), O(2)–V(1)–Cl(1) 174.7(2),
O(2)–V(1)–O(3) 83.3(3), Cl(2)–V(1)–O(1) 169.8(2), O(3)–
V(1)– N(1) 175.2(3)
[2,6-iPr2C6H3N=CHC6H2(CPh3)tBuO]V(H2O)Cl
units
were connected by two chlorine bridges (see in
Figure S1). The water molecule is in trans position to the
terminal chlorine atom. The solid- structures of 4 and
5
were also confirmed by X-ray crystallography
(Figures 4 and 5). In 4 the two chlorine atoms are in trans
position whereas in 5 the two chlorine atoms are in cis
position. The bond distances and angels in 4 and 5 are
well comparable to those in 1. The molecular structures
described above reveal that, the incorporation of trityl
group into the FI vanadium complexes may change the
cis/trans configuration of the chlorine atoms (or THF
molecules) probably due to the repulsion of the trityl
Cl(2) angle (87.9(3)ꢁ) and O(2)–V(1)–O(3) angle
(83.31(3)ꢁ). The vanadium atom is almost coplanar with
the FI ligand plane with a deviation of (0.092 Å). One of
the THF molecules is situated in the valley formed by
two aryl rings of ortho-trityl moiety. Such orientation can
efficiently decrease the steric congestion at the metal
FIGURE 3 Perspective view of 2·H2O with thermal ellipsoids
drawn at 30% probability level. Hydrogens are omitted for clarity.
The selected bond lengths (Å) and angles (deg.):
FIGURE 4 Perspective view of 4 with thermal ellipsoids
drawn at 30% probability level. Hydrogens are omitted for clarity.
The selected bond lengths (Å) and angles (deg.): V(1)–O(1) 1.876(3),
V(1)–N(1) 2.091(3), V(1)–O(2) 2.130(3), V(1)–O(3) 2.172(3),
V(1)–Cl(1) 2.3297(12), V(1)–Cl(2) 2.3632(11);
V(1)–O(1) 1.8911(19), V(1)–N(1) 2.100(2), V(1)–O(2) 2.217(2),
V(1)–O(3) 2.069(2), V(1)–Cl(1) 2.3793(8), V(1)–Cl(2) 2.3487(8);
Cl(1)–V(1)–Cl(2) 168.60(3), O(1)–V(1)–O(3) 178.68(9),
O(1)–V(1)–O(2) 91.07(8), N(1)–V(1)–O(1) 87.75(9)
Cl(1)–V(1)–Cl(2) 170.90(5), O(1)–V(1)–N(1) 90.10(11),
O(2)–V(1)–O(3) 84.52(10)

HAO ET AL.
5 of 11
showed slight dependence on the Al/V ratio and the
activity of 1 increased from 4.28 × 104 to 5.08 × 104 Kg
PE·mol (V)−1·h−1 when Al/V ratio increased from 1,000:1
to 2000:1. But further increase the Al/V ratio to 3,000:1
the activity drops slightly. Interestingly, the molecular
weights of the polymer were not affected greatly by the
Al/V ratio in the range of 1,000 ꢀ 3,000 (entry 1–3). It
was reported that, in the catalytic systems with 7 or 8, the
molecular weight of the polymer decreased gradually
with the increase of Et2AlCl concentration probably due
to the chain transfer from vanadium to aluminum.[4a] We
believe that in the o-trityl FI-vanadium systems the chain
migration from the active species to the aluminum spe-
cies may be suppressed by the bulky ortho trityl group.
The polymerization temperature showed little influence
on the activities. The catalytic activities of complex
1 decrease slightly with an increase of temperature, while
the molecular weights of the resulted polymers are not
varied greatly with temperature. Upon activation with
2000 equiv of Et2AlCl at room temperature complexes
2–6 also showed high activities in ethylene polymeriza-
tion. Complex 2 with two bulky ortho-iPr groups in the
N-aryl moiety showed higher activities than 1 under the
same condition (entry 6). On introducing two
trifluoromethyl (electron-withdrawinggroup) into the
3,5-positions of N-aryl moiety, to form complex 3, cata-
lytic activity did not change much when compared with
the system involving 1. However, when two methoxyl
(donating group) were introduced into the 3,5-position of
N-aryl moiety in the ligand the activity decreased about
20%. Complex 5 which possess a cumyl group in imino
moiety showed the highest activity among these com-
plexes. Further increase the steric hindrance around the
metal center by introducing a Ph3C group in imino moi-
ety, to form complex 6, the activity decreases slightly.
The decrease in activity should be ascribed to that the
bulky substitutes may suppress the chain propagation
during the polymerization. A great deal of research has
shown that solvent play an important role in vanadium
system for olefin polymerization. For example, the
ethylene polymerization with VCl2(N-2,6-Me2C6H3)(O-
Me2C6H3)/Et2AlCl in CH2Cl2 exhibited higher activities
than in toluene, while the activities in n-hexane were
very low.[5g] Our catalytic systems of 1–6/Et2AlCl showed
enhanced activities in CH2Cl2 affording the polymers
with high molecular weight (entry 11 ꢀ 16) in which
complex 4 showed the highest activities and the produc-
tivity up to 7.52 × 104 Kg PE·mol (V)−1·h−1 was obtained.
Unexpectedly, 1–6/Et2AlCl showed very high activity in
hexane (entry 17 ꢀ 22) and a productivity of 6.72 × 104
Kg PE·mol (V)−1·h−1 was obtained with 3/Et2AlCl/in
hexane. This result is in contrast to the VCl2(N-2,-
6-Me2C6H3)(O-Me2C6H3)/Et2AlCl system which showed
FIGURE 5 Perspective view of 5 with thermal ellipsoids
drawn at 30% probability level. Hydrogens are omitted for clarity.
The selected bond lengths (Å) and angles (deg.): V(1)–O(1) 1.905(3),
V(1)–N(1) 2.111(4), V(1)–O(2) 2.109(3), V(1)–O(3) 2.123(4),
V(1)–Cl(1) 2.3326(15), V(1)–Cl(2) 2.3828(15); Cl(1)–V(1)–
Cl(2) 92.50(6), O(1)–V(1)–N(1) 87.68(14)
group. But the bond lengths and angles involving metal
center does not alter greatly when compared to the FI
vanadium analogous with o-tBu or o-H groups. The two
phenyl rings stretch out to the outer sphere of the metal
center. The out-sphere protection may not prohibit the
uptake of monomer in the polymerization but may sup-
press the β-hydrogen elimination and chain transfer dur-
ing the polymerization.
2.3 | Catalysis on olefin polymerization
Complexes 1–6 were evaluated as pre-catalysts for ethyl-
ene polymerization under the activation with Et2AlCl.
The polymerization results are listed in Table 1. The com-
plexes [2,6-iPr2PhN=CH(C6H2 Bu2)O]VCl2(THF)2 (7) and
t
[2,6-iPr2PhN=CH(C6H3 tBu)O]VCl2(THF)2 (8) were also
tested for comparation. Complexes 1–6 showed low activ-
ity for ethylene polymerization when only Et2AlCl was
used. As proven previously, the poor activity may be
ascribed to the reduction of the V (III) to low valent spe-
cies during the activation with alkyl aluminum com-
pounds.[2g] Some oxidant reagent such as Cl3CCO2Et
were generally needed to maintain the activity. As
expected, when small amount of Cl3CCO2Et was added
the 1–6/Et2AlCl catalytic systems showed high activities
in ethylene polymerization. For example, the productivity
of 4.28 × 104 Kg PE·mol (V)−1·h−1 was obtained by using
0.1 μmol of 1 and 1,000 equiv of Et2AlCl at room temper-
ature in the presence of 0.03 mL Cl3CCO2Et. The activity

6 of 11
HAO ET AL.
TABLE 1
Polymerization of ethylene with 1–6/Et2AlCla
Entry
1
Catalyst
Al/V
1,000
2000
3,000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
2000
T (ꢁC)
25
25
25
50
70
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
25
Solvent
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
Tolueue
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
Hexane
Hexane
Hexane
Hexane
Hexane
Hexane
Tolueue
Tolueue
Tolueue
Yield (g)
1.07
1.27
1.14
1.12
1.08
1.35
1.23
1.02
1.44
1.14
1.39
1.60
1.85
1.88
1.40
1.15
1.48
1.61
1.68
1.66
1.53
1.25
0.88
1.04
1.52
Activityb (×104)
4.28
Mwc (×104)
8.4
PDI
2.5
2.6
2.9
2.9
2.8
2.4
1.8
2.7
2.8
2.2
2.6
2.7
2.9
3.1
2.7
2.8
2.7
2.6
2.4
2.5
2.8
2.7
5.6
2.8
2.4
M.p.d
138.3
139.5
139.7
138.8
139.4
137.6
141.4
141.1
139.5
141.3
140.3
139.7
138.4
139.3
142.9
137.9
142.2
141.0
139.9
139.2
139.6
140.1
140.2
139.8
139.9
1
2
1
5.08
9.1
3
1
4.56
9.7
4
1
4.48
10.2
9.0
5
1
4.32
6
2
5.40
6.4
7
3
4.92
11.8
11.1
9.9
8
4
4.08
9
5
5.76
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
6
4.56
8.3
1
5.56
8.2
2
6.40
6.5
3
7.40
11.6
7.3
4
7.52
5
5.60
6.4
6
4.60
5.9
1
5.92
6.1
2
6.44
7.3
3
6.72
8.8
4
6.64
8.6
5
6.12
7.4
6
5.00
7.8
VCl3(THF)3
3.22
18.2
5.2
7
8
4.08
6.41
4.3
aPolymerization conditions: solvent (60 ml), cat (0.1 μmol based on V), Cl3CCO2Et = 0.03 mL; 5 bar; 15 min.
bActivity in unit of Kg PE·mol(V)−1·h−1
cDetermined by GPC relative to polystyrene standards.
dDetermined by DSC at a heating of 10 ꢁC min−1
.
.
very low activity in hexane.[5g] Complexes 7 and 8 with
small ortho group in ligand showed similar activities
under the same conditions affording the polymers with
relative lower molecular-weight when compared with
those derived from o-trityl FI vanadium systems. This
result suggested that the bulky o-trityl group which offer
an efficient out-sphere protection may suppress the
chain-transfer and β-H elimination during the polymeri-
zation giving the polymers with relatively high
molecular-weight. The 13C NMR spectroscopy analysis
shows that all the polymers obtained with 1–6/Et2AlCl
catalytic systems are highly linear with the melting point
in the range of 137.6–142.9 ꢁC (see Figure S2).
those with Et2AlCl (Table 2). Interestingly, the molecular
weights of the resulted polymer derived from the 1–6/
MAO (MMAO) are greatly higher than those with
Et2AlCl and the polymers with molecular weight up to
3.30 × 106 Da were obtained with 2/MMAO at room tem-
perature (see Figure S4).
Complexes 1–6 were also used to catalyze the eth-
ylene/hexene copolymerization and the representative
results are summarized in Table 3. When activated with
Et2AlCl, complexes 1–6 show high activities toward eth-
ylene/hexene copolymerization and give the high molec-
ular weight copolymers with unimodal molecular weight
distributions (Ð 2.8 ꢀ 3.6). The co-monomer incorpora-
tions of 6.0 ꢀ 7.8% were obtained. The representative 13C
NMR and GPC data of the polymer see Figure S3 and S5.
When MAO or MMAO was used as co-catalyst, com-
plexes 1–6 show relatively lower activities compared to

HAO ET AL.
7 of 11
TABLE 2
Polymerization of ethylene with 1–6/MAO (MMAO)a
Entry
Catalyst
Co-catalyst
MAO
Yield (g)
0.12
Activityb
960
Mwc (×106)
1.68
PDI
1.9
2.1
1.6
2.7
2.6
2.3
1.7
2.5
2.4
2.4
2.3
2.0
M.p.d
1
1
2
3
4
5
6
1
2
3
4
5
6
135.5
138.1
138.4
136.4
136.8
137.1
137.1
138.0
135.5
135.7
136.2
136.7
2
MAO
0.28
2,240
1,200
2,160
2,720
1,280
2,240
3,920
2,880
2,400
4,640
1840
1.75
3
MAO
0.15
1.13
4
MAO
0.27
0.87
5
MAO
0.34
1.35
6
MAO
0.16
1.27
7
MMAO
MMAO
MMAO
MMAO
MMAO
MMAO
0.28
2.64
8
0.49
3.30
9
0.36
2.68
10
11
12
0.30
2.69
0.58
2.89
0.23
2.26
aPolymerization conditions: toluene (60 ml), cat (0.5 μmol based on V), Cl3CCO2Et = 0.05 ml, Al/V molar ratio = 400, temperature 25 ꢁC,
ethylene pressure 5 bar, time 15 min.
bActivity in unit of Kg of PE·mol (V)−1·h−1
.
cDetermined by GPC relative to polystyrene standards.
dDetermined by DSC at a heating of 10 ꢁC min−1
.
TABLE 3
Ethylene/1-hexene copolymerization 1–6/Et2AlCla
Run
Catalyst
Al/V
400
400
400
400
400
400
Yield (g)
1.79
Activityb (×103)
Hexenec content
Mwd (×104)
PDI
3.0
3.4
2.9
2.8
3.6
3.5
1
2
3
4
5
6
1
2
3
4
5
6
7.2
6.5
7.1
6.0
7.8
7.0
6.6
6.9
8.5
8.9
1.65
2.55
10.2
11.4
6.8
5.6
2.85
5.1
1.70
11.1
11.5
1.69
6.7
aPolymerization conditions: toluene 60 ml,1.0 μmol, Cl3CCO2Et = 0.05 ml, 15 min, hexene 0.75 mol/l, temperature 25 ꢁC.
bActivity in unit of Kg of PE·mol (V)−1·h−1
.
cCalculated on the basis of 13C NMR spectra.
dDetermined by GPC relative to polystyrene standards.
3 | CONCLUSION
1-hexene affording the polymers with moderate co-
monomer incorporations (6.0 ꢀ 7.8%).
A series of o-trityl phenoxy-imine ligands were synthe-
sized and used to support the vanadium (III) complexes.
All these complexes were fully characterized and some of
their solid structures were further confirmed by X-ray dif-
fraction analysis in which the vanadium atoms are in dis-
torted octahedral geometry. When combined with
Et2AlCl, these complexes showed high activities for ethyl-
4 | EXPERIMENTAL
4.1 | General considerations
All manipulations involving air- and moisture-sensitive
compounds were carried out under an atmosphere of
dried and purified nitrogen using standard Schlenk and
vacuum-line techniques. Toluene and THF were dried
over sodium metal and distilled under nitrogen prior to
use. Elemental analyses were performed on a Varian EL
microanalyzer. CH2Cl2, hexane and 1-hexene were puri-
fied by distilling over calcium hydride before use. NMR
ene
polymerization
(activities
up
to
7.52 × 104 g·mol−1(V)·h−1) affording the polymers with
moderate molecular-weight. While MAO (MMAO) was
used, these complexes can polymerize ethylene to ultra-
high molecular weight polymers (up to 3.30 × 106 Da)
with narrow PDI (<3). These complexes also showed
high activities in the copolymerization of ethylene with

8 of 11
HAO ET AL.
spectra were carried out on a Varian 400 MHz instru-
ment at room temperature in CDCl3 solution for ligands.
13C NMR spectra of the copolymers were recorded on a
7.50 mmol). L2H was obtained as yellow solid. Yield
2.56 g (88.3%). 1H NMR (400 MHz, CDCl3, 25 ꢁC): δ
1.07–1.09 (d, 12H, CH (CH3)2), 1.21 (s, 9H, C (CH3)3),
2.81–2.88 (m, 2H, CH (CH3)2), 7.10 (s, 2H, Ar-H),
7.15–7.18 (t, 3H, Ar-H), 7.22–7.30 (m, 14H, Ar-H), 7.46 (s,
1H, Ar-H), 8.24 (s, 1H, CH=N), 13.30 (s, 1H, Ar-OH)
ppm. C NMR (100 MHz, CDCl3, 25 C): δ 23.45 (s, 4C,
ArCH (CH3)2), 28.06 (s, 2C,ArCH (CH3)2), 31.36 (s,3C,C
(CH3)3), 34.20 (s, 1C,C (CH3)3), 63.53 (s, 1C, C (Ph)3),
117.95, 123.11, 125.19, 125.61, 127.16, 127.39, 131.08,
132.75, 134.69, 138.65, 140.18, 145.58, 146.10, 158.23,
166.68 (s, 1C, CH=N) ppm.
ꢁ
Varian Unity-400 NMR spectrometer at 135 C with o-
C6D4Cl2 as the solvent. The molecular weights (MWs)
and polydispersity indices (PDIs) of the polymer samples
13
ꢁ
ꢁ
were determined at 150 C by a PL-GPC 220 type high-
temperature
gel
permeation
chromatograph.
1,2,4-Trichlorobenzene was employed as the solvent at a
flow rate of 1.0 mL/min. The differential scanning calo-
rimetry (DSC) measurements were performed on a
Netzsch DSC 204 instrument under a N2 atmosphere.
The samples were heated at a rate of 10 ꢁC/min and
ꢁ
cooled at a rate of 10 C/min. The melting peaks were
4.2.3 | Synthesis of L3H
obtained by analyzing the second heating graph. 3,5-Bis
(trifluoromethyl)aniline,
3,5-dimethoxyaniline,
L3H was synthesized in the same way as described for
L1H using 5-tert-butyl-2-hydroxybenzaldehyde (2.10 g,
5.00 mmol) and 3,5-bis (trifluoromethyl)aniline (1.72 g,
7.50 mmol). L3H was obtained as yellow solid. Yield
2.67 g (84.5%). H NMR (400 MHz, CDCl3, 25 C): δ 1.22
(s, 9H, C (CH3)3), 7.18–7.25 (m, 15H, Ar-H), 7.37 (s, 1H,
Ar-H), 7.52 (s, 1H, Ar-H), 7.60 (s, 2H, Ar-H), 7.72 (s, 1H,
Ar-H), 8.65 (s, 1H, CH=N), 12.63 (s, 1H, Ar-OH) ppm.
triphenylmethanamine, diphenylmethanamine, and tri-
phenylchloromethane were purchased from Aldrich.
Ethyl trichloroacetate (ETA) was purchased from TCI.
5-tert-butyl-2-hydroxy-3-tritylbenzaldehyde[12]
and
1
ꢁ
VCl3(THF)3 was prepared according to the literature.[15]
The representative 13C NMR and GPC data of the poly-
mers are given in Figures S2-S5.
13
ꢁ
C NMR (100 MHz, CDCl3, 25 C): δ 31.25 (s, 3C, C
(CH3)3), 34.26 (s, 1C,C (CH3)3), 63.70 (s, 1C, C (Ph)3),
118.07, 119.72, 121.56, 121.71, 124.42, 125.74, 127.26,
128.47, 130.99, 132.62, 132.95, 134.01, 134.79, 141.03,
145.25, 149.98, 158.16, 165.88 (s, 1C, CH=N) ppm.
4.2 | Synthesis of ligands L1H-L6H
4.2.1 | Synthesis of L1H
5-tert-butyl-2-hydroxy-3-tritylbenzaldehyde
(2.10
g,
5.00 mmol) and 2,6-dimethylaniline (0.91 g, 7.50 mmol)
was dissolved in 30 ml of anhydrous methanol, and a few
drops of formic acid were added. After refluxing for 12 hr
the mixture was evaporated to dryness and the residue
was treated with cold methanol to give the L1H as yellow
powder. Yield 2.27 g (86.7%). 1H NMR (400 MHz, CDCl3,
4.2.4 | Synthesis of L4H
L4H was synthesized in the same way as described for
L1H using 5-tert-butyl-2-hydroxybenzaldehyde (2.10 g,
5.00 mmol) and 3,5-dimethoxyaniline (1.15 g, 7.50 mmol).
L4H was obtained as yellow solid. Yield 2.21 g (79.7%).
1H NMR (400 MHz, CDCl3, 25 ꢁC): δ 1.20 (s, 9H, C
(CH3)3), 3.77 (s, 6H, Ar-OCH3), 6.35–6.39 (m, 3H, Ar-H),
7.18–7.31 (m, 16H, Ar-H), 7.42 (s, 1H, Ar-H), 8.59 (s, 1H,
CH=N), 13ꢁ.23 (s, 1H,Ar-OH) ppm. 13C NMR (100 MHz,
CDCl3, 25 C): δ 31.30 (s, 3C, C (CH3)3), 34.15 (s,1C, C
(CH3)3), 55.53 (s, 2C, Ar-OCH3), 63.43 (s, 1C, C (Ph)3),
99.17, 99.38, 118.42, 125.63, 127.19, 127.89, 131.03,
132.76, 134.35, 140.34, 145.48, 150.39, 157.99, 161.26,
163.16 (s, 1C, CH=N) ppm.
ꢁ
25 C): δ 1.20 (t, 9H, C (CH3)3), 2.08 (s, 6H, Ar-CH3),
6.92–6.96 (t, 1H, Ar-H), 7.01–7.03 (d, 2H, Ar-H),
7.14–7.18 (t, 4H, Ar-H), 7.22–7.29 (m, 12H, Ar-H), 7.45 (s,
1H, Ar-H), 8.29 (s, 1H, CH=N), 13.19 (s, 1H, Ar-OH)
13
ꢁ
ppm. C NMR (100 MHz, CDCl3, 25 C): δ 18.47 (s, 2C,
Ar-CH3), 31.38 (s, 3C, C (CH3)3), 34.20 (s, 1C, C (CH3)3),
63.52 (s, 1C, C (Ph)3), 118.06, 124.70, 125.62, 127.18,
127.47, 127.68, 128.23, 128.31, 131.10, 132.69, 134.58,
140.17, 145.60, 148.03, 158.18, 166.95 (s, 1C,
CH=N) ppm.
4.2.5 | Synthesis of L5H
4.2.2 | Synthesis of L2H
L5H was synthesized in the same way as described for
L1H using 5-tert-butyl-2-hydroxybenzaldehyde (2.10 g,
5.00 mmol) and aminodiphenylmethane (1.37 g,
7.50 mmol). L5H was obtained as yellow solid. Yield
L2H was synthesized in the same way as described for
L1H using 5-tert-butyl-2-hydroxybenzaldehyde (2.10 g,
5.00 mmol) and 2,6-diisopropylaniline (1.33 g,

HAO ET AL.
9 of 11
1
nBuLi (2.00 M in hexane, 0.50 ml, 1.00 mmol), and
VCl3(THF)3 (0.38 g, 1.00 mmol). Complex 2 was obtained
as dark red powders (yield 0.53 g, 62.5%). The crystals of
2 suitable for X-ray structural determination were grown
from THF/hexane mixed solution. Anal. Calcd for
C50H60Cl2NO3V(%): C, 71.08; H, 7.16; N, 1.66. Found: C,
ꢁ
2.38 g (81.4%). H NMR (400 MHz, CDCl3, 25 C): δ 1.15
(s, 9H, C (CH3)3), 5.54 (s, 1H, CH (Ph)2), 7.15–7.20 (m,
12H, Ar-H), 7.22–7.27 (m, 14H, Ar-H), 7.35 (s, 1H, Ar-H),
8.40 (s, 1H, CH=N), 13.30 (s, 1H, Ar-OH) ppm. 13C NMR
(100 MHz, CDCl3, 25 ꢁC): δ 31.38 (s, 3C, C (CH3)3), 34.14
(s,1C, C (CH3)3), 63.53 (s, 1C, C (Ph)3), 76.72 (s, 1C, N-
CH (Ph)2) 125.57, 118.29, 127.17, 127.27,127.38,127.69,
128.55, 131.10, 132.04, 134.20, 139.98, 142.44, 145.64,
157.81, 165.61 (s, 1C, CH=N) ppm.
70.92; H, 7.03; N, 1.79. μeff = 2.78 μB. IR (KBr): ν (cm−1
)
3016w, 2,920 m, 2861w, 1,605 m, 1494vs, 1,445 m, 1389s,
870w, 821 s, 676w, 599 m.
4.2.6 | Synthesis of L6H
4.3.3 | Synthesis of complex 3
L6H was synthesized in the same way as described for
L1H using 5-tert-butyl-2-hydroxybenzaldehyde (2.10 g,
5.00 mmol) and tritylamine (1.30 g, 7.50 mmol). L6H was
Complex 3 was synthesized in the same way as described
above for complex 1 using L3H (0.63 g, 1.00 mmol),
nBuLi (2.00 M in hexane, 0.50 mL, 1.00 mmol), and
VCl3(THF)3 (0.38 g, 1.00 mmol). Complex 3 was obtained
as dark red powders (yield 0.53 g, 58.8%). Anal. Calcd for
C46H46Cl2F6NO3V(%): C, 61.61; H, 5.17; N, 1.56.
Found: C, 61.80; H, 5.28; N, 1.41. μeff = 2.63μB. IR (KBr):
ν (cm−1) 3014w, 2,927 m, 2,868 m, 1,607 m, 1487vs,
1,453 m, 1,392 m, 877w, 824 s, 690w, 606 m, 503w.
1
obtained as yellow solid. Yield 2.83 g (85.6%). H NMR
ꢁ
(400 MHz, CDCl3, 25 C): δ 1.13 (s, 9H, C (CH3)3), 6.97
(s, 1H, Ar-H), 7.08–7.10 (m, 6H, Ar-H), 7.14–7.18 (m, 3H,
Ar-H), 7.21–7.29 (m, 21H, Ar-H), 7.37 (s, 1H, Ar-H), 7.88
(s, 1H, CH=N), 13.94 (s, 1H, Ar-OH) ppm. 13C NMR
ꢁ
(100 MHz, CDCl3, 25 C): δ 31.52 (s, 3C,C (CH3)3), 34.26
(s,1C, C (CH3)3), 63.70 (s, 1C, C (Ph)3), 78.83 (s, 1C, N-C
(Ph)3) 118.34, 125.66, 127.27, 127.89, 128.07, 129.84,
131.28, 132.19, 134.52, 139.96, 144.42, 145.82, 158.26,
164.56 (s, 1C, CH=N) ppm.
4.3.4 | Synthesis of complex 4
Complex 4 was synthesized in the same way as described
above for complex 1 using L4H (0.56 g, 1.00 mmol),
nBuLi (2.00 M in hexane, 0.50 mL, 1.00 mmol), and
VCl3(THF)3 (0.38 g, 1.00 mmol). Complex 4 was
obtained as dark red powders (yield 0.55 g, 66.8%). The
crystals of 4 suitable for X-ray structural determination
were grown from THF/hexane mixed solution.
Anal. Calcd for C46H52Cl2NO5V(%): C, 67.32; H, 6.39; N,
1.71. Found: C, 67.19; H, 6.27; N, 1.86. μeff = 2.77μB. IR
(KBr): ν (cm−1) 2958 s, 2840 m, 2715w, 1730vs,
1584w, 1467s, 1,377 m, 1155s, 1071w, 981 m, 836 m,
739w, 496w.
4.3 | Synthesis of vanadium complexes 1–6
4.3.1 | Synthesis of complex 1
nBuLi (0.5 mL, 1.00 mmol) in n-hexane was added
dropwise to a stirred solution of L1H (0.52 g, 1.00 mmol)
ꢁ
in 30 ml of THF at −78 C. The mixture was allowed to
warm to −40 ꢁC and stirred for 30 min. VCl3(THF)3
(0.38 g, 1.00 mmol) was added in one portion and the
mixture was allowed to warm to room temperature and
stirred overnight. After removal of the solvent, the resi-
due was extracted with toluene (20 ml). Toluene was
removed in vacuum and the crude product was rec-
rystallized from CH2Cl2/hexane to give the pure complex
1 as dark red powder (0.52 g, 65.7%). Anal. Calcd for
C46H52Cl2NO3V(%): C, 70.05; H, 6.64; N, 1.78. Found: C,
4.3.5 | Synthesis of complex 5
Complex 5 was synthesized in the same way as described
above for complex 1 using L5H (0.58 g, 1.00 mmol),
nBuLi (2.00 M in hexane, 0.50 ml, 1.00 mmol), and
VCl3(THF)3 (0.38 g, 1.00 mmol). Complex 5 was obtained
as dark red powders (yield 0.61 g, 71.2%). The crystals of
5 suitable for X-ray structural determination were grown
from THF/hexane mixed solution. Anal. Calcd for
C51H54Cl2NO3V(%): C, 71.99; H, 6.40; N, 1.65. Found: C,
70.21; H, 6.49; N, 1.64. μeff = 2.81μB. IR (KBr): ν (cm−1
)
3020w, 2,935 m, 2,864 m, 1,603 m, 1504vs, 1421s, 867 m,
820 s, 682w, 601 m, 512w.
4.3.2 | Synthesis of complex 2
72.16; H, 6.58; N, 1.45. μeff = 2.82μB. IR (KBr): ν (cm−1
)
Complex 2 was synthesized in the same way as described
above for complex 1 using L2H (0.58 g, 1.00 mmol),
3027w, 2,952 m, 2854w, 1619s, 1536w, 1,487 m, 1,439 m,
1314w, 1,002 m, 843w, 752 m, 697vs, 551 m.

10 of 11
HAO ET AL.
4.3.6 | Synthesis of complex 6
ORCID
Zhiqiang Hao https://orcid.org/0000-0002-6554-803X
Complex 6 was synthesized in the same way as described
above for complex 5 using L6H (0.66 g, 1.00 mmol),
nBuLi (2.00 M in hexane, 0.50 ml, 1.00 mmol), and
VCl3(THF)3 (0.38 g, 1.00 mmol). Complex 6 was obtained
as dark red powders (yield 0.69 g, 74.3%). Anal. Calcd for
C57H58Cl2NO3V(%): C, 73.86; H, 6.31; N, 1.51. Found: C,
REFERENCES
[1] a) W. L. Carrick, J. Am. Chem. Soc. 1958, 80, 6455;
b) W. L. Carrick, R. W. Kluiber, E. F. Bonner, L. H. Wartman,
F. M. Rugg, J. Smyth, J. Am. Chem. Soc. 1960, 82, 3883;
c) G. Natta, G. Mazzanti, A. Valvassori, G. Sartori,
D. Fiumani, J. Polym. Sci. A 1961, 51, 411; d) G. W. Phillips,
73.69; H, 6.47; N, 1.69. μeff = 2.79μB. IR (KBr): ν (cm−1
)
W. L. Carrick, J. Polym. Sci.
A
1962, 59, 401;
3008w, 2,930 m, 2,867 m, 1,612 m, 1495vs, 1,446 m,
1397s, 868 m, 822 s, 683w, 600 m, 509w.
e) V. E. Junghanns, A. Gumboldt, G. Bier, Makromol. Chem.
1962, 58, 18; f) D. L. Christman, G. I. Keim, Macromolecules
1968, 1, 358.
[2] a) Y. Doi, S. Ueki, T. Keii, Macromolecules 1979, 12, 814;
b) Y. Doi, T. Koyama, K. Soga, Makromol. Chem. 1985, 186,
11; c) H. Hagen, J. Boersma, G. van Koten, Chem. Soc. Rev.
2002, 31, 357; d) S. Gambarotta, Coord. Chem. Rev. 2003, 237,
229; e) K. Nomura, W. Zhang, Chem. Sci. 2010, 1, 161;
f) C. Redshaw, Dalton Trans. 2010, 39, 5595. K. Nomura,
S. Zhang, Chem. Rev. 2010, 111, 2342; g) G. Zanchin,
L. Vendier, I. Pierro, F. Bertini, G. Ricci, C. Lorber, G. Leone,
Organometallics 2018, 37, 3181.
[3] a) Y. Nakayama, H. Bando, Y. Sonobe, Y. Suzuki, T. Fujita,
Chem. Lett. 2003, 32, 766; b) Y. Nakayama, H. Bando,
Y. Sonobe, T. Fujita, J. Mol. Catal. A: Chem. 2004, 213, 141.
[4] a) J. Q. Wu, L. Pan, N. H. Hu, Y. S. Li, Organometallics 2008,
27, 3840; b) J. Q. Wu, L. Pan, S. R. Liu, L. P. He, Y. S. Li,
J. Polym. Sci., Part a: Polym. Chem. 2009, 47, 3573; c) J. Q. Wu,
L. Pan, Y. G. Li, S. R. Liu, Y. S. Li, Organometallics 2009, 28,
1817; d) B. C. Xu, T. Hu, J. Q. Wu, N. H. Hu, Y. S. Li, Dalton
Trans. 2009, 41, 8854; e) J. Q. Wu, B. X. Li, S. W. Zhang,
Y. S. Li, J. Polym. Sci., Part a: Polym. Chem. 2010, 48, 3062; f)
J. Q. Wu, Y. G. Li, B. X. Li, Y. S. Li, Chin. J. Polym. Sci. 2011,
29, 627; g) J. B. Wang, L. P. Lu, J. Y. Liu, H. L. Mu, Y. S. Li,
J. Mol. Catal. A: Chem. 2015, 398, 289.
4.4 | Ethylene polymerization
experiments
The ethylene polymerization experiments were carried
out as follows: a dry 100 mL steel autoclave with a mag-
netic stirrer was charged with 55 ml of toluene,
thermostated at the desired temperature, and saturated
with ethylene (1.0 atm). The polymerization reaction was
started by addition of a mixture of the catalyst and
co-catalyst in toluene (5 ml) at the same time. The vessel
was pressurized to 5 atm with ethylene immediately, and
the pressure was maintained by continuous feeding of
ethylene. The mixture was stirred at the desired tempera-
ture for the desired time period. The polymerization was
then quenched by injecting an acidic ethanol solution
containing HCl (3 M). The polymer was collected by
filtration, washed with water and ethanol, and dried to a
constant weight under vacuum.
[5] a) K. Nomura, A. Sagara, Y. Imanishi, Chem. Lett. 2001, 30, 36;
b) K. Nomura, A. Sagara, Y. Imanishi, Macromolecules 2002,
35, 1583; c) W. Wang, J. Yamada, M. Fujiki, K. Nomura, Cat.
Com. 2003, 4, 159; d) W. Wang, K. Nomura, Macromolecules
2005, 38, 5905; e) Y. Onishi, S. Katao, M. Fujiki, K. Nomura,
Organometallics 2008, 27, 2590; f) K. Nomura, A. Igarashi,
S. Katao, W. Zhang, W. H. Sun, Inorg. Chem. 2013, 52, 2607;
g) W. Wang, K. Nomura, Adv. Synth. Catal. 2006, 348, 743;
h) A. Igarashi, E. L. Kolychev, M. Tamm, K. Nomura, Organo-
metallics 2016, 35, 1778; i) K. Nomura, T. Mitsudome,
A. Igarashi, G. Nagai, K. Tsutsumi, T. Ina, T. Omiya,
H. Takaya, S. Yamazoe, Organometallics 2017, 36, 530;
j) C. Bariashir, C. Huang, G. A. Solan, W.-H. Sun, Coord.
Chem. Rev. 2019, 385, 208.
[6] a) C. Redshaw, L. Warford, S. H. Dale, M. R. J. Elsegood,
Chem. Commun. 2004, 1954; b) C. Redshaw, M. A. Rowan,
D. M. Homden, S. H. Dale, M. R. Elsegood, S. Matsui,
S. Matsuura, Chem. Commun. 2006, 3329; c) D. M. Homden,
C. Redshaw, D. L. Hughes, Inorg. Chem. 2007, 46, 10827; d)
L. Clowes, M. Walton, C. Redshaw, Y. Chao, A. Walton,
P. Elo, V. Sumerin, D. L. Hughes, Cat. Sci. Technol. 2013, 3,
152; e) J. Ma, K. Q. Zhao, M. J. Walton, J. A. Wright,
J. W. Frese, M. R. Elsegood, Q. F. Xing, W. H. Sun,
C. Redshaw, Dalton Trans. 2014, 43, 8300; f) J. Ma,
4.5 | Crystallography
The crystals were mounted on a glass fiber using the oil
drop. Data obtained with the ω-2θ□ scan mode were col-
lected on a Bruker SMART 1000 CCD diffractometer with
graphite-monochromated Kα radiation (λ = 0.71073 Å).
The structures were solved using direct methods, while
further refinement with full-matrix least squares on F2
was obtained with the SHELXTL program package. All
non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were introduced in calculated positions
with the displacement factors of the host carbon atoms.
The crystal data and summary of X-ray data collection
are given in Table S1 in Supporting Information.
ACKNOWLEDGMENTS
We thank financial supports from the National Natural
Science Foundation of China for project Nos. 21574052,
U1462111, 51673078, 21603082.

HAO ET AL.
11 of 11
K. Q. Zhao, M. Walton, J. A. Wright, D. L. Hughes,
[11] H. Terao, A. Iwashita, N. Matsukawa, S. Ishii, M. Mitani,
H. Tanaka, T. Nakano, T. Fujita, ACS Catal. 2011, 1, 254.
[12] S. Ay, M. Neiger, S. Bräse, Chem. A Eur. J. 2008, 14, 11539.
[13] D. F. Evans, J. Chem. Soc. 1959, 2003.
M. R. Elsegood, K. Michiue, X. Sun, C. Redshaw, Dalton
Trans. 2014, 43, 16698; g) C. Redshaw, M. J. Walton, D. S. Lee,
C. Jiang, M. R. Elsegood, K. Michiue, Chem. A Eur. J. 2015, 21,
5199; h) C. Redshaw, Y. Tang, Chem. Soc. Rev. 2012, 41, 4484.
[7] a) D. Reardon, F. Conan, S. Gambarotta, G. Yap, Q. Wang,
J. Am. Chem. Soc. 1999, 121, 9318; b) Z. Janas,
L. B. Jerzykiewicz, P. Sobota, R. L. Richards, Chem. Commun.
1999, 1105; c) S. Milione, G. Cavallo, C. Tedesco, A. Grassi,
J. Chem. Soc. Dalton Trans. 2002, 1839; d) T. Rüther,
K. J. Cavell, N. C. Braussaud, B. W. Skelton, A. H. S. White,
J. Chem. Soc. Dalton Trans. 2002, 4684; e) D. S. McGuinness,
V. C. Gibson, J. W. Steed, Organometallics 2004, 23, 6288;
f) M. Biazek, K. Czaja, J. Polym. Sci., Part a: Polym. Chem.
2008, 46, 6940; g) G. Leone, I. Pierro, G. Zanchin, A. Forni,
F. Bertini, A. Rapallo, G. Ricci, J. Mol. Catal. A: Chem. 2016,
424, 220; h) N. A. Kolosov, V. A. Tuskaev, S. C. Gagieva,
I. V. Fedyanin, V. N. Khrustalev, O. V. Polyakova,
B. M. Bulychev, Eur. Polym. J. 2017, 87, 266.
ꢀ
[14] aA. Gansnuer, Tetrahedron 2002, 58, 7017. bA. K. Tomov,
V. C. Gibson, D. Zaher, M. R. J. Elsegood, S. H. Dale, Chem.
Commun. 2004, 1956.
[15] A. Gansäuer, B. A. Rinker, Tetrahedron 2002, 58, 7017.
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How to cite this article: Hao Z, Li F, Gao W. o-
Trityl phenoxy-imino vanadium (III) complexes:
synthesis, characterization, and catalysis on
ethylene (co)polymerization. Appl Organomet
Chem. 2020;e5809. https://doi.org/10.1002/aoc.
5809
[8] H. Makio, H. Terao, A. Iwashita, T. Fujita, Chem. Rev. 2011,
111, 2363.
[9] E. Yao, J. Wang, Z. Chen, Y. Ma, Macromolecules 2014, 47,
8164.
[10] A. Li, H. Ma, J. Huang, Appl. Organomet. Chem. 2013, 27, 341.
S. Matsui, T. Fujita, Catal. Today 2001, 66, 63.