Synthesis of telechelic olefin polymers via catalyzed chain growth on multinuclear alkylene zinc compounds

Article abstract of DOI:10.1021/ja403626g

Multinuclear alkylene zinc (MAZ) compounds of the type EtZn-(R″-Zn) _n-Et (R″ = ethyl and propyl branched alkylene groups) were synthesized by a simple one-step procedure in nonpolar hydrocarbon solvents from α,ω-dienes (e.g., 1,7-octadiene or 1,9-decadiene) and diethylzinc using a bis(salicylaldiminato)Zr(IV) complex, [(2-methylcyclohexyl)N=CH(2-O- C₆H₃-3,5-di-tert-butyl)]₂ZrMe₂, as a catalyst. The MAZ serves as a divalent reversible chain-transfer agent for olefin polymerization, resulting in telechelic Zn-metalated polyolefins whose molecular weights are controllable over a wide range. The Zn-terminated telechelics serve as a polymer precursor for further reactions and can be converted into a variety of telechelic functionalized polyolefins in high yield.

Full text of DOI:10.1021/ja403626g

Subscriber access provided by Mount Allison University | Libraries and Archives
Communication
Synthesis of Telechelic Olefin Polymers via Catalyzed
Chain Growth on Multinuclear Alkylene Zinc Compounds
Haruyuki Makio, Takashi Ochiai, Jun-ichi Mohri, Kouji Takeda, Toshiyuki
Shimazaki, Yoko Usui, Sadahiko Matsuura, and Terunori Fujita
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/ja403626g • Publication Date (Web): 15 May 2013
Downloaded from http://pubs.acs.org on May 16, 2013
Just Accepted
“Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted
online prior to technical editing, formatting for publication and author proofing. The American Chemical
Society provides “Just Accepted” as a free service to the research community to expedite the
dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts
appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been
fully peer reviewed, but should not be considered the official version of record. They are accessible to all
readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered
to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published
in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just
Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor
changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers
and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors
or consequences arising from the use of information contained in these “Just Accepted” manuscripts.
Journal of the American Chemical Society is published by the American Chemical
Society. 1155 Sixteenth Street N.W., Washington, DC 20036
Published by American Chemical Society. Copyright © American Chemical Society.
However, no copyright claim is made to original U.S. Government works, or works
produced by employees of any Commonwealth realm Crown government in the course
of their duties.

Page 1 of 5
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
Synthesis of Telechelic Olefin Polymers via Catalyzed Chain
Growth on Multinuclear Alkylene Zinc Compounds
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Haruyuki Makio,*,† Takashi Ochiai,¶ Jun-ichi Mohri,¶ Kouji Takeda,¶ Toshiyuki Shimazaki,¶ Yoko
Usui,¶ Sadahiko Matsuura,¶ and Terunori Fujita†
†Mitsui Chemicals Singapore R&D Centre, 50 Science Park Road, Kendall, Science Park II Singapore 117406
¶R&D Center, Mitsui Chemicals, Inc., 580-32 Nagaura, Sodegaura, Chiba, 299-0265, Japan
Supporting Information Placeholder
of reachable molecular weights, applicable main chain structures,
and the variety of chain-end functional groups.
ABSTRACT: Multinuclear alkylene zinc compounds (MAZ) of
the type EtZn-(R"-Zn)n-Et (R": ethyl and propyl branched al-
Catalyzed chain growth (CCG) on main group metals is a process
kylene groups) were synthesized by a simple one-step procedure
in which a reversible transmetallation takes place between transi-
in non-polar hydrocarbon solvents from α,ω-dienes (e.g., 1,7-
octadiene or 1,9-decadiene) and diethylzinc (DEZ) using a
tion metal alkyl species responsible for chain propagation and
main group metal alkyls.8 Polymer chains carried by main group
bis(salicylaldiminato)Zr(IV)
complex,
[(2-
metals are inactive for polymerization and subject to chain growth
only when transferred back to a catalytically active transition
metal species through transmetallation. The transmetallation oc-
curs at a statistically equal probability at a comparable rate to
chain propagation for all main group metal alkyls, and thus CCG
affords polymers with a Poisson distribution that are quantitative-
ly capped with the main group metals. Unlike living polymeriza-
tion, CCG requires a much less stoichiometric amount of transi-
tion metal catalyst to polymer chains and can also operate in a
continuous process. Hence, a catalyzed chain growth on zinc has
been successfully applied to the manufacturing of olefin block
copolymers on an industrial scale.9 Recently, Boisson and D'Ago-
sto reported that telechelic PE was successfully prepared using
CCG with bis(10-undecenyl)magnesium and a neodymium cata-
lyst.10 Although it works well, the obtained telechelic polymers
were limited to PE as the Nd catalyst could polymerize only eth-
ylene, and the PE molecular weights remained at Mn~1,500, pre-
sumably, I believe, to avoid precipitation of high molecular
weight PE (polymerization was carried out at 75 °C).
methylcyclohexyl)N=CH(2-O-C6H3-3,5-ditert-butyl)]2ZrCl2 (1),
as a catalyst. The MAZ serve as a divalent reversible chain trans-
fer agent for olefin polymerization, resulting in telechelic Zn-
metalated polyolefins whose molecular weights are controllable
over a wide range. The Zn-terminated telechelics serve as a poly-
mer precursor for further reactions and can be converted into a
variety of telechelic functionalized polyolefins in high yield.
Telechelic polymers refer to macromolecules possessing two well-
defined reactive functional groups situated at the chain termini.1
Progress in single-site transition metal catalyzed polymerization
of non-polar olefins such as ethylene and propylene has allowed
the synthesis of polyolefins having unprecedented structural fea-
tures such as monodisperse molecular weight polyolefins, olefin
block copolymers, ethylene copolymers with vinyl functionalized
monomers, and hyper-branched polyolefins.2 Nevertheless, re-
search on telechelic polyolefins with well-defined structures has
been rather limited, for example, (a) The pyrolysis of high molec-
ular weight polypropylene,3 (b) The metathesis degradation of
polybutadienes followed by functionalization and hydrogenation,
resulting in a telechelic polyethylene (PE),4 (c) ROMP in the
presence of an acyclic internal olefin as a chain transfer agent
(ROMP-CT)1,5 which also requires subsequent hydrogenation to
form a telechelic PE, and (d) Living polymerization using func-
tionalized initiators followed by chain-end capping.6 In our own
research efforts, we have developed a series of robust living
polymerization catalysts with bis(salicylaldiminato)Ti complexes
(Ti-FI catalysts) bearing fluorinated N-aryl groups.7 The active
species derived from the fluorinated Ti-FI catalysts are well-
defined and thermally so robust that functional initiators can be
quantitatively prepared in situ via single insertion of functional-
ized α-olefins to the living Ti-Me species and also living chain
ends can be quantitatively functionalized after polymerization.6b
However, the living polymerization protocol inherently imposes
some restrictions, namely 1) One catalyst molecule forms only
one polymer chain; and 2) It is difficult to apply to an industrially
relevant continuous processes. These drawbacks result in signifi-
cant cost disadvantages for large scale manufacturing. Likewise,
all the approaches raised above have some shortcomings in terms
In this article, we would like to present a new process enabling a
catalytic synthesis of high molecular weight telechelic polyolefins
via CCG in the presence of multinuclear alkylene zinc compounds
(MAZ) to provide a solution for the problems described above.
We believe that our method displays advantages over that of
Boisson and D'Agosto because we can obtain a higher molecular
weight range, a more versatile main chain structure, and a higher
polymerization activity.
In CCG with dialkylzinc, the divalent zinc metal carries two pol-
ymer chains and these polymers are considered to be end func-
tionalized with zinc albeit only at one chain end (mono-telechelic,
Scheme 1). If the alkyl groups on zinc in this polymerization are
substituted with divalent alkylene groups (-R"-) having two Zn-C
bonds in one molecule, telechelic polyolefins should result, in
theory (Scheme 1). However, synthesis of such divalent alkylene
multinuclear metal compounds is not straightforward. If one tries
to apply common practices for the synthesis of alkylzinc com-
pounds (alkylation of zinc halides, transmetallation of alkyl-
boranes and Et2Zn, etc.) to divalent alkylene zinc compounds, the
challenges to be involved are: 1) Commercial unavailability of
divalent alkylene metal agents (M-R"-M, M: main group metal);
2) Multistep reactions including purification; 3) Low atom econ-
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 2 of 5
omy (formation of metal halide salts or BEt3); 4) Possible use of
when used as a chain transfer agent (CTA), resulting in long chain
branching.
1
2
3
4
oxygen-containing polar solvents which cause adverse impacts in
subsequent polymerization steps even if only a minute amount is
carried over.
There are several key criteria to select an appropriate catalyst for
this reaction: 1) High efficiency for olefin insertion (path i); 2)
Prohibitive second olefin insertion (path ii); 3) Rapid transmetal-
lation (path iii); 4) Negligible β-H transfer reaction (path iv).
Scheme 1. CCG with mono- and multinuclear zinc com-
pounds
5
Complex
1
[(2-methylcyclohexyl)N=CH(2-O-C6H3-3,5-ditert-
6
7
8
9
butyl)]2ZrMe2 (Chart) and MAO/borate cocatalysts are highly
active toward ethylene polymerization and yet very sensitive to
steric environments and thus two consecutive insertions of higher
α-olefins are practically impossible.11 In addition, this catalyst is
also capable of CCG on Zn, meaning that transmetallation with
alkylzinc is much more facile than the second monomer insertion.
Lastly, the catalyst affords very high molecular weight PE,12
which fulfills requirement 4).
Mononuclear
R'
:
R Zn R
*
x
*
R'
(R' = H or alkyl)
Fn: functional group
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
R
Zn
Fn
R
CCG
x 2 (mono-telechelics)
R
CHART. Catalyst precursors capable of CCG on zinc al-
kyls
Multinuclear
R"
R Zn
R'
Zn
R
n
iPr
R
Zn
R"
R
Zn
CCG
ZrMe2
N
n
N
iPr
2
O
tBu
Fn
x n (telechelics)
N
R"
Fn
Fn
Hf
Me
tBu
Me
x 2 (mono-telechelics)
R
iPr
1
5
Since olefin insertion to an M'-C bond is a facile and atom-
economic reaction to form C-C and C-M' bonds simultaneously
(M': transition metal), we envisioned the following reactions to
prepare multinuclear alkylene zinc compounds (MAZ) to address
all the challenges discussed above (Scheme 2).
The reactions using 1,9-decadiene and DEZ were carried out in
hexane in the presence of 1 and MMAO/Ph3CB(C6F5)4. The
products were hydrolyzed and the organic layer was analyzed by
gas chromatography (Table 1).
TABLE 1. Synthesis of multinuclear alkylene zinca
Scheme 2. Synthesis of multinuclear alkylene zinc via pol-
yaddition reaction
Et
Et
Et
1
1) Et2Zn,
2) H+
+
+
R"
R"
6
Et
6
+
Et2Zn
EtZn
Zn
Et
6
6
Et
Et
Zr-FI catalyst
n
Et
Et
R"
2
3
4
entry
1,9-
DEZ
2
3
4
complex 1
R"
Zn
LnZr
Et
decadiene
mol/L
0.2
c
c
c
equiv.b
%
%
%
mmol/L
Et
1
2
2.0
2.0
1.2
1.2
2.5
2.1
1.5
1.5
1.5
1.1
74
74
76
92
79
24
24
22
8
2
2
2
0
1
iii)
i)
0.2
3
0.12
4d
5e
0.12
R"
Et Zn
LnZr
iv)
Et
0.50
20
R"
aReactions were carried out at 20 °C for 30 min in hexane using
MMAO and Ph3CB(C6F5)4 as cocatalysts (Zr/Al/B=1/14‒ 20/2
ii)
LnZr
R"
b
c
d
R"
molar ratio). To 1,9-decadiene. GC area ratios. Reaction at 0
Et
°C. edMAO instead of MMAO.
R" Et
R": alkylene chain
____________________________________________________
The overall reaction is a polyaddition reaction between two bi-
functional monomers, i.e., α,ω-dienes (e.g., 1,7-octadiene or 1,9-
decadiene) and diethylzinc (ZnEt2). The reaction is catalyzed
by an olefin polymerization catalyst through repetitive olefin
insertion and transmetallation until all vinyl groups or Zn-Et
groups are consumed. The degree of polymerization, "n", can be
determined by molar ratios of diene and ZnEt2 (DEZ) and high
molecular weight products will result when DEZ/diene is close to
one (DEZ/diene = 1.0). When DEZ/diene > 1, the polymer chain
ends will be exclusively Zn-CH2CH3. In the opposite cases
(DEZ/diene < 1), the vinyl groups will remain at the chain ends,
which can be engaged in olefin polymerization in the next step
Within 30 min, 1,9-decadiene was completely consumed. Upon
hydrolysis, three products were identified with a different regio-
chemistry regarding Zn-C bond addition over two double bonds
in the diene, namely, 1,2-1,2 adduct (2), 1,2-2,1 adduct (3), and
2,1-2,1 adduct (4). The selectivity for 1,2-addition is about 87%
(0.87×0.87=0.75) at 20 °C, which increases to 96% at 0 °C (entry
4). The products derived from multiple diene insertions (path ii),
cyclization, insertion only at one vinyl group of diene (the other
one is left untouched), and β-H elimination resulting in a vinyli-
dene group (path iv), were not detected.13
A portion of the products (entry 4) was taken and the solvents
were distilled off to take NMR spectra. The broad signals that
ACS Paragon Plus Environment

Page 3 of 5
Journal of the American Chemical Society
1
appeared in H NMR spectrum support the polymeric nature of
the products. Neither the signals for DEZ nor any unsaturated
bonds are discernible.14 The 13C NMR spectrum was complicated
due to the mixed isomeric units but the signals for the main iso-
meric unit can be assigned.
from major n-butyl chain ends. No sec-butyl branches were ob-
served. The regio-selectivity of the Zn-Et addition at 20 °C was
about 87/13 for 1,2- and the 2,1- addition as discussed above.
Since each regiochemistry results in ethyl and propyl branches
upon multiple insertions of ethylene monomers between Zn-C
bonds (Scheme 4), the observed branch composition demonstrates
that CCG from primary Zn-C bonds (1,2-adduct) and secondary
Zn-C bonds (2,1-adduct) is equally facile under the conditions
and that Zn-bound alkylene groups in MAZ serve as an efficient
divalent chain transfer agent.
1
2
3
4
5
6
7
8
The 13C signals for Zn-CH2CH3 appear at δ 10.4 (Cβ) and 7.4
(Cα), which are similar but clearly distinguishable from the ones
for DEZ (δ 10.3, 6.7) that are not observed in the product.14 How-
ever, the peak intensity of Zn-Et is clearly smaller than the one
expected from the molar ratio of the reactants. Furthermore, when
fresh DEZ was added to this NMR sample, the signals for DEZ
did not appear. These observations suggest that there is a rapid
equilibrium between each MAZ molecule as shown in Scheme 3.
Therefore, upon removal or addition of DEZ the degrees of
polymerization ("n" in Scheme 2) are controllable. In fact, the
degree of polymerization can reach as high as n = 40 or higher
after excessive removal of DEZ under a high vacuum by shifting
the equilibrium in Scheme 3 to the right.
9
Scheme 4. Branch formation derived from MAZ
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
R"
R"
Zn
Zn
x
CCG
CCG
Et
Et
1,2-adduct
Ethyl branch
Et
Zn
R"
R"
x
Scheme 3. Equilibrium between MAZ species
Zn
Et
Propyl branch
R"
R"
2,1-adduct
EtZn
Zn
+ EtZn
Zn
Et
Et
p
q
To further confirm the formation of telechelic PE capped with Zn
and to obtain telechelic end-functionalized PE, chemical conver-
sion of the Zn-C bonds were attempted using a highly reactive
acyl chloride. When ethyl succinyl chloride (ESC) was added at 6
equivalents to Zn at 120 °C after the polymerization, the Zn-CH2-
bonds were converted to EtOCOCH2CH2COCH2- at 89-96% es-
timated by 1H NMR. A typical example is shown in Figure 1. For
this particular example, the functionality (Fn(%)/100: functional-
ized chain ends/all chain ends) can be estimated at Fn= 82% from
Et
Et
EtZn
Et
Et
R"
+ Et2Zn
Zn
Et
p+q
Et
Et
The MAZ prepared by this method was then applied for ethylene
polymerization. We selected complex 1 as an ethylene polymeri-
zation catalyst because it is capable of performing well-controlled
CCG with DEZ. The polymerization results are compiled in Table
2. Complex 1 yielded high molecular weight PE having reasona-
ble molecular weight distribution at high activity in the absence of
any CTA (entry 6). In the presence of DEZ under otherwise the
same conditions, the molecular weight of PE dropped dramatical-
ly and molecular weight distribution narrowed without significant
changes in activity (entry 7), which is in line with the efficient
CCG. When MAZ was employed instead of DEZ (entry 8), the
polymerization afforded PE with similar molecular weight distri-
bution at comparable activity but the molecular weight became
higher than the PE derived from DEZ. This would be in accord-
ance with our hypothesis, where polymers that are linked by al-
kylene groups in MAZ should have a molecular weight about
twice as high as those generated from Zn-Et bonds (Scheme 1).
1
the H NMR integral ratios of all the methyl groups appearing
around δ 0.8-0.95 ppm (chain ends that are not functionalized and
branches derived from alkylene groups of MAZ) and the 4-
ethoxy-4-oxobutanoyl group of ESC. The DEZ/diene ratio of
1
MAZ used in this polymerization is 1.098 (determined by H
NMR as a mixture of reactants), from which theoretical values,
n=10.2 and Fn=83.6% are elucidated. The observed Fn (82%) is
slightly lower than the theoretical value possibly because the mi-
nor chain transfer to MAO (or trimethylaluminum) is included
therein.
O
c
f
O
a
d
e
b
O
a
TABLE 2. Ethylene polymerization with complex 1 in the
presence of zinc-based CTAa
f
c
c
entry
CTA
none
DEZ
MAZd 0.12
MAZe 0.48
[Zn], mM
activityb
12.0
Mn
Mw/Mn
1.70
f
b
d c e
f
6
7
8
9
0
19940
5770
7950
1990
0.12
10.7
1.46
11.2
1.46
8
7
6
5
4
3
2
1
8.6
1.78
1
FIGURE 1. H NMR spectrum of a telechelic PE equipped with
4-ethoxy-4-oxobutanoyl group at 82% functionality in C2D2Cl4 at
120 °C (entry 9 in Table 2).
aReactions were carried out at 120 °C for 10 min under 0.7 MPa
of ethylene pressure in hexane (5 mL as total volume) using
MMAO
and
Ph3CB(C6F5)4
as
cocatalysts
(Zr/Al/B=0.0002/0.020/0.0008 mmol). bIn kg-PE/mmol-Zr h.
The MAZ we so far used for polymerization includes active com-
plex 1 albeit in small amounts, which will irreproducibly cause
unwanted polymeric byproducts when a catalyst other than 1 is
used in a subsequent polymerization. Besides, the MAO remain-
ing in MAZ may decrease the Fn values by serving as univalent
CTA. Therefore, complex 1 was anchored onto SiO2-supported
MAO and the heterogenized complex 1 was used as a catalyst to
prepare MAZ in the absence of additional cocatalysts such as
MAO or borate. The reactions are as efficient as homogeneous
catalyst 1 and after the heterogeneous catalyst was filtered off, the
cDetemined by GPC (PE calibration). The product from entry 2.
d
eThe product from entry 5.
____________________________________________________
In order to examine whether MAZ units are incorporated into
polymer chains, low molecular weight PE was prepared by in-
creasing the concentration of MAZ (entry 9). After hydrolysis,
microstructures of the PE were investigated by 13C NMR,14 which
revealed ethyl and propyl branches at 89/11 molar ratio aside
ACS Paragon Plus Environment

Journal of the American Chemical Society
Page 4 of 5
remaining MAZ has no color (unlike the red to orange homoge-
1
2
3
4
neous catalyst system, Figure 2) and contains only a minute
amount of aluminum or zirconium (below 0.1% relative to Zn
where [Zn] is around 0.5 M). In addition, the filtered heterogene-
ous catalyst can be reused for MAZ preparation several times
over.
ASSOCIATED COMMENT
Supporting Information Available: NMR spectra and GPC elution
curves. This material is available free of charge via the Internet at
http://pubs.acs.org.
5
6
AUTHOR INFORMATION
7
Corresponding Author: haruyuki.makio@mitsui-chem.co.jp
8
9
REFERENCES
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
(1) Tasdelen, M. A.; Kahveci, M. U.; Yagci, Y. Prog. Polym. Sci. 2011,
36, 455–567.
(2) (a) Fujita, T.; Makio, H. Comprehensive Organometallic Chemistry
III, Vol. 11, Eds: Crabtree, R. H.; Mingos, D. M. P., Volume Ed:
Hiyama, T.: Elsevier, Amsterdam, 2007, pp 691–734. (b) Gibson, V.
C.; Spitzmesser, S. K. Chem. Rev., 2003, 103, 283–315.
(3) (a) Sawaguchi, T.; Suzuki, Y.; Sakaki, A.; Saito, H.; Seno, M. Polym.
Int. 2000, 49, 921–925. (b) Sawaguchi, T.; Ikemura, T.; Seno, M.
Macromolecules 1995, 28, 7973–7978.
(4) (a) Shiono, T.; Naga, N.; Soga, K. Makromol. Chem. Rapid Commun.
1993, 14, 323–327.
(5) (a) Sill, K.; Emrick, T. J. Polym. Sci. Part A 2005, 43, 5429–5439.
(b) Pitet, L. M.; Amendt, M. A.; Hillmyer, M. A. J. Am. Chem. Soc.
2010, 132, 8230–8231.
(6) (a) Gottfried, A. C.; Brookhart, M. Macromolecules 2003, 36, 3085–
3100. (b) Makio, H.; Fujita, T. Macromol. Rapid Commun. 2007, 28,
698–703.
(7) (a) Mitani, M.; Nakano, T.; Fujita, T. Chem. Eur. J. 2003, 9, 2396–
2403. (b) Makio, H.; Kashiwa, N.; Fujita, T. Adv. Synth. Catal.
2002, 344, 477–493. (c) Makio, H.; Terao, H.; Iwashita, A.; Fujita, T.
Chem. Rev. 2011, 111, 2363–2449.
(8) (a) Samsel, E. G.; Eisenberg, D. C. EP-0574854, 1993. (b) Pelletier,
J.-F.; Mortreux, A.; Olonde, X.; Bujadoux, K. Angew. Chem., Int. Ed.
Engl. 1996, 35, 1854–1856. (c) Britovsek, G. J. P.; Cohen, S. A.;
Gibson, V. C.; Maddox, P. J.; van Meurs, M. Angew. Chem., Int. Ed.,
2002, 41, 489–491. (d) Britovsek, G. J. P.; Cohen, S. A.; Gibson, V.
C.; van Meurs, M. J. Am. Chem. Soc., 2004, 126, 10701–10712. (e)
Kretschmer, W. P.; Meetsma, A.; Hessen, B.; Schmalz, T.; Qayyum,
S.; Kempe, R. Chem. Eur. J., 2006, 12, 8969–8978.
(9) Arriola, D. J.; Carnahan, E. M.; Hustad, P. D.; Kuhlman, R. L.;
Wenzel, T. T. Science 2006, 312, 714–719.
(10)German, I.; Kelhifi, W.; Norsic, S.; Boisson, C.; D'Agosto, F. Angew.
Chem. Int. Ed. 2013, 52, 3438–3441.
(11)Makio, H.; Ochiai, T.; Tanaka, H.; Fujita, T. Adv. Synth. Catal. 2010,
352, 1635–1640.
(12)Terao, H.; Ishii, S.; Saito, J.; Matsuura, S.; Mitani, M.; Nagai, N.;
Tanaka, H.; Fujita, T. Macromolecules, 2006, 39, 8584–8593.
(13)The absence of the byproducts was confirmed using GC-MS and
NMR. Cyclic products for 1,7-octadiene and 1,9-decadiene were not
observed while 1-ethyl-3-methylcyclopentane was detected after hy-
drolysis when 1,5-hexadiene was used.
FIGURE 2. MAZ prepared with homogeneous 1/MMAO/
Ph3CB(C6F5)4 (left) and with SiO2-supported 1/MAO (right).
The MAZ prepared with the heterogeneous catalyst was tested
with hafnium pyridyl-amide complex 5, which is known to be a
good comonomer incorporator and also capable of polymerizing
olefins in a well controlled CCG fashion.9 In copolymerization of
ethylene and propylene followed by reaction with ESC, telechelic
elastomer terminated by ester groups was successfully synthesized
(Activity: 133.4 kg-polymer (mmol-Hf h)-1; Mw (PSt): 39,000;
Mw/Mn: 2.13; Propylene content (IR): 25.1 mol%, due to the over-
lapping signals at 1,100-1,200 cm-1, the value may not be accu-
rate.).
In conclusion, we have developed a simple and efficient one-pot
method to synthesize multinuclear alkylene zinc compounds
(MAZ) from DEZ and diene using a Zr-FI catalyst. The degree of
polymerization of MAZ can be controlled either by adjusting the
DEZ/diene molar ratios or by adding or removing DEZ afterward
to shift the equilibrium. MAZ can also be prepared by heterogen-
ized 1/MAO/SiO2 catalysts, where the obtained MAZ has no Al
or Zr contaminations in the liquid phase. MAZ can serve as a
reversible divalent chain transfer agent in CCG reactions, yielding
telechelic zinc metalated polyolefins in high efficiency. Molecular
weights of the telechelic Zn polymers are controllable by adjust-
ing [olefins]/[Zn] molar ratios and reach at least Mn ~104. Main
chain compositions can be varied from crystalline polyethylene to
elastic ethylene-α-olefin copolymers, and possibly to isotactic
polypropylene.15 Unlike living polymerization, the telechelic pol-
yolefin manufacturing technology developed in this study will be
applicable to an industrial continuous solution tank reactor pro-
cess just by replacing common metal alkyls with MAZ. The ob-
tained Zn-terminated telechelic polyolefins are highly reactive and
versatile polymer precursors which can be converted to end-
functionalized polyolefins at high yield.
(14)See Supporting Information.
(15) Boussie, T. R.; Diamond, G. M.; Goh, C.; Hall, K. A.; LaPointe, A.
M.; Leclerc, M. K.; Murphy, V.; Shoemaker, J. A. W.; Turner, H.;
Rosen, R. K.; Stevens, J. C.; Alfano, F.; Busico, V.; Cipullo, R.; Tal-
arico G. Angew. Chem. Int. Ed. 2006, 45, 3278–3283.
ACKNOWLEDGMENT
H.M. would like to thank Munehito Funaya, Kouji Endo, Mayumi
Hiwara and Katsuyuki Harada for their technical support and
helpful suggestions.
ACS Paragon Plus Environment

Page 5 of 5
Journal of the American Chemical Society
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
ACS Paragon Plus Environment