Interaction of oxygen functionalized alkenes with a methylaluminoxane-zirconocene catalyst studied by NMR

Article abstract of DOI:10.1016/S0022-328X(98)01219-4

Reactions of hydroxyl, ether and carbonyl functionalized alkenes with methylaluminoxane prepared in toluene-d₈ (MAO) and zirconocenedichloride (Cp₂ZrCl₂) were investigated by ¹H- and ¹³C-NMR spectroscopy at 27°C. The 11 alkenes studied bear a terminal C=C bond separated by 7-9 (-CH₂-) units from the heteroatom moiety. Intramolecular connectivities in mono (alkene), bi (alkene and MAO) and tri (alkene, MAO and Cp₂ZrCl₂) component mixtures were determined by 2D HSQC, HMBC, ROESY and NOESY NMR techniques. The five studied alkenols formed aluminium alkoxides with MAO even in the case of a substantial steric hindrance around the OH group. Zirconocene enhanced the formation of aluminium alkoxides. Decomposition to free alkenol was observed only for the straight chain alkenol (10-undecen-1-ol). The OTMS derivatives formed dimers of the type CH₂=CR₁R₂ along with methyl derivatives, CH₂=C(Me)(R) and (Me)CH=CH(R), in the presence of MAO and Cp₂ZrCl₂. 10-Undecenyl methyl ether and methyl decenoate remained mainly as a free comonomer in the presence of MAO or MAO/Cp₂ZrCl₂, though a transient coordination of the former to MAO was deduced. Unsaturated species Me₂C=CH-Al-X and CH₂=CH(CH₂)₅CH₂CH=C(t-Bu)O-Al-X (X = MAO oligomer) were formed in the reaction of t-butyl undecenoate or 2,2-dimethyl-11-dodecen-3-one with MAO or MAO/Cp₂ZrCl₂. Interaction of the CH₂=CH part of the functionalized alkenes with zirconocene was not observed. A possible coordination of the C=C bond to MAO was observed only for the sec alkenols.

Full text of DOI:10.1016/S0022-328X(98)01219-4

Journal of Organometallic Chemistry 579 (1999) 164–176
Interaction of oxygen functionalized alkenes with a
methylaluminoxane–zirconocene catalyst studied by NMR
Tuulamari Helaja a,*, Kimmo Hakala b, Juho Helaja a, Barbro Lo¨fgren b
a Department of Chemistry, PO Box 55, Uni6ersity of Helsinki, FIN-00014 Helsinki, Finland
b Polymer Science Center, Helsinki Uni6ersity of Technology, PO Box 356, FIN-02150 Espoo, Finland
Received 28 September 1998
Abstract
Reactions of hydroxyl, ether and carbonyl functionalized alkenes with methylaluminoxane prepared in toluene-d8 (MAO) and
1
zirconocenedichloride (Cp2ZrCl2) were investigated by H- and 13C-NMR spectroscopy at 27°C. The 11 alkenes studied bear a
terminal CꢀC bond separated by 7–9 (–CH2–) units from the heteroatom moiety. Intramolecular connectivities in mono (alkene),
bi (alkene and MAO) and tri (alkene, MAO and Cp2ZrCl2) component mixtures were determined by 2D HSQC, HMBC, ROESY
and NOESY NMR techniques. The five studied alkenols formed aluminium alkoxides with MAO even in the case of a substantial
steric hindrance around the OH group. Zirconocene enhanced the formation of aluminium alkoxides. Decomposition to free
alkenol was observed only for the straight chain alkenol (10-undecen-1-ol). The OTMS derivatives formed dimers of the type
CH2ꢀCR1R2 along with methyl derivatives, CH2ꢀC(Me)(R) and (Me)CHꢀCH(R), in the presence of MAO and Cp2ZrCl2.
10-Undecenyl methyl ether and methyl decenoate remained mainly as a free comonomer in the presence of MAO or
MAO/Cp2ZrCl2, though a transient coordination of the former to MAO was deduced. Unsaturated species Me2CꢀCH–Al–X and
CH2ꢀCH(CH2)5CH2CHꢀC(t-Bu)O–Al–X (X=MAO oligomer) were formed in the reaction of t-butyl undecenoate or 2,2-
dimethyl-11-dodecen-3-one with MAO or MAO/Cp2ZrCl2. Interaction of the CH2ꢀCH part of the functionalized alkenes with
zirconocene was not observed. A possible coordination of the CꢀC bond to MAO was observed only for the sec alkenols. © 1999
Elsevier Science S.A. All rights reserved.
Keywords: Functionalized alkenes; Zirconocene–methylaluminoxane catalyst; NMR
1. Introduction
alumoxanes, [(t-Bu)Al(m3-O)]n (n=6,8,9), support the
latter [7].
The structural features of MAO and its oligomeric
interconversion have been extensively studied by H-,
The MAO–zirconocene interaction has been moni-
1
1
tored by H-, 13C-, 27Al- and 91Zr-solution NMR [3,8–
13C-, 17O- and 27Al-NMR [1–6]. It is suggested that
residual trimethylaluminium (TMA) in MAO solution
participates in the interconversion of linear, branched
and cyclic MAO oligomers. In addition to the linear
and cyclic oligomers the presence of clusters with three
coordinated oxo ligands has been proposed (Scheme 1).
The synthesis and structural characterization of cage
12] and solid-state XPS [13] or CPMAS [14] techniques.
Scheme 1. The suggested structural elements of MAO: (a) linear, (b)
cyclic and (c) cage structures (methyl groups have been omitted for
clarity) [1,7].
* Corresponding author. Fax: +358-9-1914-0366.
E-mail address: tuulamari.helaja@helsinki.fi (T. Helaja)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(98)01219-4

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
165
Scheme 2. The structures of alkenols studied: 10-undecen-1-ol (1), 2,2-dimethyl-12-tridecen-1-ol (2), 12-tridecen-2-ol (3), 2,2,4,4-tetramethyl-14-
pentadecen-3-ol (4) and 2,3,3-trimethyl-13-tetradecen-2-ol (5). The numbers refer to the characteristic 1H and 13C atoms monitored by NMR.
These indicate a formation of a [Cp2ZrR]+ cation
stabilized by an [R-MAO]− counterion and a subse-
quent displacement of the anion by an olefin molecule
in polymerization (R=alkyl, Cp=cyclopentadienyl
Table 1
Characteristic chemical shift values (l, ppm) for mono-, bi- and tri-component mixtures of alkenols 1–5 measured in toluene-d8 (multiplicity of
the observed 1H-NMR signal is given in parentheses and the atomic numbers refer to Scheme 2)
Compound number
Atomic number
Alkenol
Alkenol with MAO or MAO/Cp2ZrCl2
1H l (ppm)
13C l (ppm)
1H l (ppm)
13C l (ppm)
1
2
1
2
3.45 (t)
1.40 (m)
62.7
33.3
4.00 (m)
1.90 (bm)
64.6
33.3
1
3.13 (s)
0.83 (s)
71.7
24.1
3.44 (s)
* 3.58 (s)
0.82 (s)
73.2
* 84.7
24.1
21, 22
3
4
1
2
1.05 (d)
3.58 (m)
23.8
67.7
1.14 (d)
23.3
71.1
3.81 (m)
* 3.88 (m)
* 1.00 a (s)
* 1.03 b (s)
1.15c (s)
* 2.95 a (d)
* 3.40 b (s)
3.66c (s)
* 0.96 a (s)
* 0.98 b
* 80.5
* 29.1 a
* 29.7 b
31.0 c
* 83.7 a
* 100.1 b
92.5c
1, 21, 22
1.00 (s)
2.95 (s)
0.96 (s)
29.1
3
83.7
41, 42
25.6 and 26.0
n.r.
n.r.
n.r.
* 1.01 b
1.08 c
26.83 c,i
26.82 c,i
1.16 c
5
1, 21
1.03 (s)
0.85 (s)
25.6
1.35 a
1.47 b
1.49 c
25.6 a
26.2 b,ii
26.1 c,ii
85.6 a
2
74.9
21.6
86.1 b,c
22.4 a
31, 32
0.89 a
0.93 b
0.94 c
22.7 b,iii
22.8 c,iii
* Detected only in the presence of Cp2ZrCl2.
a ,b
c
and refer to the different molecular fragments present in the bi- or tri-component mixtures, (i, ii, iii) mutually interchangeable signals, n.r.,
not resolved.

166
T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
and 13C-NMR spectroscopy. Intramolecular connectivi-
ties between nuclei have been deduced by HSQC,
HMBC, ROESY and NOESY 2D NMR techniques.
1H-1H ROESY and NOESY measurements have been
further performed to reveal the possible catalyst coordi-
nation to the vinyl and/or heteroatom moiety of the
comonomer and to have an insight into the spatial
vicinity of the protons in the bi- or tri-component
systems. Comparison of the NMR and actual ethene or
propene copolymerization results is also briefly
described.
2. Results and discussion
2.1. Reactions of alkenols with the MAO–Cp2ZrCl2
catalyst system
Five hydroxyl functionalized alkenes 1–5 (Scheme 2)
with varying degrees of steric hindrance around the
oxygen atom were allowed to react with the MAO–
Cp2ZrCl2 catalyst system. The interaction(s) between
the alkenol and the catalyst system were analyzed by
1
comparing the characteristic H- and 13C-NMR reso-
nances of pure alkenol (mono component) to the sig-
nals observed for the bi (alkenol and MAO)- and tri
(alkenol, MAO and Cp2ZrCl2)-component mixtures
(Table 1).
1
Fig. 1. The H-NMR spectrum (500 MHz) of (A) 1, (B) 1 and MAO,
(C) 1, MAO and Cp2ZrCl2 and (D) aged 1 (300 MHz), MAO and
Cp2ZrCl2 referenced* to the residual CHD2 in toluene-d8. The num-
bering refers to Scheme 2. Different Cp2Zr species are marked with
superscripts a–c.
2.1.1. Primary alkenol 1
1
The H-NMR spectra of compound 1 measured in
different component systems are presented in Fig. 1(A–
D). The 1-CH2 of free alkenol 1 has the chemical shift
value l 3.45 ppm (Fig. 1(A)). These protons were
shifted to a lower field at l 4.00 ppm, when the NMR
sample contained an equimolar amount of MAO (Fig.
1(B)). Simultaneously their multiplicity changed from a
triplet to a fine-structured doublet presumably due to
the unsymmetry induced by different MAO fragments.
The chemical shift values and the multiplicity of the
observed proton signals remained the same, when a
catalytic amount of Cp2ZrCl2 was added to the mixture
of 1 and MAO (Fig. 1(C)). Additional multiplets at l
3.50–4.40 ppm, barely visible in the bi-component mix-
ture, became more pronounced in the tri-component
mixture of 1.
On the basis of HSQC spectra the 1-CH2 resonance
of 1 assigned at l 62.7 ppm had shifted (Dl(C)=1.9
ppm) to an upper value of 64.6 ppm measured in the bi-
and tri-component systems. Two HMBC correlations
(Fig. 2) between a 1H singlet (l −0.30 ppm) and
1-CH2 or 2-CH2 resonances (64.6 and 33.3 ppm) were
detected indicating the formation of an aluminium
alkoxide. Chemical shift values of −0.35 ppm [2],
−0.38 ppm [4] and −0.40 ppm [6] are generally at-
tributed to TMA present as a free dimer (Al2Me6) or
ligand). Recently, an ion-pair complex of a cage alu-
moxane, [(t-Bu)Al(m3-O)]6, and Cp2ZrMe2 has been de-
tected and proven to be an active catalyst for ethene
polymerization [15].
In addition to the spectroscopic investigations of
MAO or MAO–zirconocene interaction, reactions of
cage alumoxanes and of related alkylalumoxanes with
different heteroatom compounds have been reported
[16–19]. However, interaction(s) appearing in a three-
component system of the polar comonomer, MAO and
zirconocene has not been thoroughly investigated.
We have previously studied the synthesis of func-
tional polyolefins through direct polymerization of
ethene or propene and some polar oxygen functional-
ized comonomers with soluble zirconocene–MAO cata-
lysts [20–23]. The catalyst deactivation was observed to
vary depending on the structural features of a polar
monomer utilized in the copolymerization.
In the present study, interaction of OH, OR, CO2R
and CꢀO functionalized long-chain alkenes with MAO
prepared [24] in toluene-d8 solution and a Cp2ZrCl2
catalyst are discussed. The mono (pure alkene)-, bi
(alkene/MAO)- and tri (alkene/MAO/Cp2ZrCl2)-com-
1
ponent reaction mixtures were investigated using H-

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
167
Fig. 2. The expanded HMBC (500 MHz) spectrum of 1 and MAO.
mainly bound to MAO. Alternatively, O–Al(CH3)2
chain-end methyl protons of MAO oligomers could
appear at l−0.38 ppm [4].
the values measured for the pure 1. Hence, the origi-
nally formed aluminium alkoxides seem to be unstable
under the experimental conditions.
We assume that there exists one main aluminium
alkoxide and a few minor similar components based on
the observed HMBC correlations and the TROESY
spectrum measured from the bi- or tri-component mix-
tures of 1. The ROE correlations (Fig. 3) arising from
the spectral area of 3.50–4.40 ppm to the group of
singlets at l −0.26 to −0.46 ppm suggest that com-
pound 1 has reacted with MAO oligomers and thus
produced different RCH2–O–Al– fragments, of which
the main species could be formed from the residual
TMA present in MAO. In that case the main compo-
nent has most likely a trimeric structure since dimethyl-
aluminium alkoxides, Me2Al(OR) with straight-chain
hydrocarbon substituents (R), have been observed to
favor the trimeric form in solution [25].
The pronounced effect of aging is also noticed by
inspecting the chemical shift values of cyclopentadienyl
protons (Cp). Pure Cp2ZrCl2 has its Cp resonance (s) at
l 5.88 ppm (lC 116.0 ppm). In the freshly measured
1
tri-component H-NMR spectrum (Fig. 1(C)), two ad-
ditional Cp resonances were observed: one at the upper
value of 5.95 ppm (lC 113.5 ppm) and the other at the
lower value of 5.78 ppm (lC 112.6 ppm). The chemical
shift value of 5.74–5.76 ppm has been assigned to the
Cp moiety of Cp2ZrCH3Cl whereas the l value of
0.36–0.43 ppm was obtained for the Zr–CH3 resonance
depending on the concentration of MAO [11]. These
1
can both be identified in the H-NMR spectrum pre-
sented in Fig. 1(C). We assume that the upper l value
(5.95 ppm) is produced by coordination of MAO or
When the NMR sample containing 1, MAO and
Cp2ZrCl2 was allowed to stand for a few weeks in the
dark, some gelatinous material was formed in the NMR
TMA aluminium to a chlorine of Cp2ZrCl2 or
Cp2ZrCH3Cl on the basis of induced downfield shift
(DlH=0.07 ppm compared to Cp2ZrCl2). These types
of complexes have been suggested to occur in a reaction
of MAO and Cp2ZrCl2 [1,8,9,11].
1
tube. Subsequently, both the H- and 13C-NMR spectra
had changed significantly. Now a 1H resonance with the
appearance of a deceptive quartet was detected at l
3.36 ppm (Fig. 1(D)). A coupling constant of 5.5 Hz
was obtained for the deceptive quartet and the triplet at
l 0.62 ppm indicating that they are part of the same
spin system. Based on the HSQC and HMBC spectra
these signals are most likely the 1-CH2 and OH of free
alkenol 1. The assigned OH proton showed distinct
HMBC correlations to the 1-CH2, 2-CH2 and 3-CH2
resonances (l 62.5, 33.0 and 26.5 ppm) attributable to
1
The original Cp signals were absent at the H spec-
trum recorded from the aged tri-component mixture
(Fig. 1(D)). Two proton resonances (bs) having the l
values 6.29 and 6.47 ppm (lC 133.5 and 133.0 ppm)
were found with a mutual HMBC correlation instead.
Such lowfield resonances have been earlier reported for
Cp2Zr+(Me)O(CH2)nCHꢀCH2 (n=1–3) cations with
anionic counterions [26]. However, the observed lC
values, 133.5 and 133.0 ppm, are not in agreement with

168
T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
Fig. 3. The expanded TROESY (500 MHz) spectrum of 1 and MAO; correlations are marked with arrows.
the chemical shifts commonly assigned for Cp car-
bons in Cp2Zr+(R)(L) (L=ligand), Cp2Zr(OR)2 or
Cp2Zr(R)OR [10,26,27]. Presumably the high lC val-
ues obtained are due to a substituent attached to the
Cp ring. This is supported by the HMBC correlations
detected between the resonances at lH 2.70 ppm (lC
41.8 ppm) and lC 133.5 ppm as well as at lH 6.29
ppm and lC 41.8 ppm.
ROE correlations to 1-CH2 at l 3.44 and 3.70 ppm,
respectively.
For compound 3, ROE correlations from the 2-CH
signals (br) at l 4.14 and 4.28 ppm to the Al–CH3
signals (unresolved) at l −0.30 to −0.48 ppm were
recorded in the presence of MAO. Additional weak
ROE correlations were observed for the mixture of 3,
MAO and Cp2ZrCl2. The 13-CH2 (l 5.00 ppm, m)
and 11-CH2 protons exhibited ROE correlations to
the Al-CH3 (l −0.30 ppm, unresolved) and Al–CH3
(bs, centered at l −0.10 ppm), correspondingly.
The Cp signals measured for the tri-component
mixtures of 2 or 3 (Fig. 4) appear approximately at
the same l values as described for compound 1 (Fig.
1(C)). Thus the interaction of the olefinic part of 3
and MAO manifested at the ROESY spectrum is
2.1.2. Primary and secondary alkenols 2 and 3
Several partly overlapping –C(Me2)CH2–O– and
–CH(Me)–O– resonances appeared at l 3.40–4.40
ppm, when the NMR spectrum was measured from a
mixture of compound 2 or 3 and MAO–Cp2ZrCl2
(Fig. 4(A–B)). Consequently the geminal C–O reso-
nances (l 70–85 ppm) from the HSQC spectra could
no longer be unequivocally deduced with the excep-
tions noted in Table 1. HMBC correlations could be
observed from the different 21/22-CH3 of 2 (l 0.80–
1.20 ppm) and 1-CH3 of 3 (l 1.00–1.25 ppm) to the
corresponding 1-C–O (l 73.0–84.7 ppm) and 2-C–O
(l 71.0–80.5 ppm) signals.
Obviously various –C(Me2)CH2–O– and –CH-
(Me)–O– species are produced from structurally dif-
ferent MAO oligomers. This is supported by the
ROESY spectra of 2 or 3 and the catalyst system.
The 1-CH2 resonances of
2 (l 3.44–4.10 ppm)
showed ROE correlations to the 21/22-CH3 signals (l
0.80–1.20 ppm). The partly overlapping Al–CH3 res-
onances centred at l −0.40 and −0.38 ppm had
Fig. 4. The 1H-NMR spectrum (600 MHz) of (A) 2, MAO and
Cp2ZrCl2 and (B) 3, MAO and Cp2ZrCl2.

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
169
Fig. 5. The expanded HMBC and HSQC spectrum (300 MHz) of aged 4, MAO and Cp2ZrCl2.
probably induced by the suitable structure of sec
alkenol 3 and not by a zirconocene species absent in the
reaction mixtures of prim alkenol 1 or 2. Moreover, the
decomposition of the formed alkoxides as described for
the straight chain alkenol 1 did not occur in the tri-
component mixtures of the branched compounds 2 or
3.
HMBC correlations to the 13C resonances at l 40.8
(Cq), 38.1 (Cq), 31.0 (1-CH3, 21-CH3 and 22-CH3),
1
26.83, 26.82 (41-CH3 and 42-CH3) ppm. A H–1H ROE
1
correlation was detected between the 3-CH and a H
triplet (l −0.20 ppm, br) supporting the formation of
an aluminium alkoxide. The vinyl 15-CH2 of 4 (l 5.00
ppm) exhibited a weak ROE correlation to the broad
signal of MAO (l 0.00 ppm) as described earlier for the
tri-component mixture of 3.
2.1.3. Secondary and tertiary alkenols 4 and 5
The addition of Cp2ZrCl2 produced another alu-
minium alkoxide having its 3-CH resonance at l 3.40
ppm (Table 1). The originally formed alkoxide (lH 3.66
ppm) and free 4 (lH 2.95 ppm) were detected as well.
After keeping the NMR sample for a few weeks in the
dark, the intensity ratio 1:1:1 originally observed for
the 3-CH protons at l 3.66, 3.40 and 2.95 ppm was
readjusted to 3:5:1. The analysis of the 2D spectra
Compound 4 represents a sec alcohol with a substan-
tial steric hindrance around the oxygen atom. The
3-CH (s) resonance for pure 4 was observed at l 2.95
ppm. In the bi-component system a single lower field
3-CH signal (l 3.66 ppm, s) was detected. Obviously
the bulky alkyl groups of 4 prevent the OH group from
forming the multiple CH–O– species found for the sec
alkenol 3. The 3-CH (l 3.66 ppm) signal showed

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T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
Fig. 6. The expanded 1H-NMR spectrum (500 MHz) of (A) 5, (B) 5 and MAO and (C) (300 MHz) 5, MAO and Cp2ZrCl2.
measured from the mono-, bi- and tri-component mix-
tures confirmed the existence of these separate 3-CH–
O– molecular fragments. The extended HSQC and
HMBC spectra with the characteristic signals marked
a–c for the three separate fragments are presented in
Fig. 5.
cal shift values of 1.35 (1-CH3/21-CH3), 0.89 (31-CH3/
32-CH3) and −0.27 (Al–CH3) ppm.
The addition of Cp2ZrCl2 into the mixture of 5 and
MAO produced few additional signals (Fig. 6(C)) in the
1H and 13C spectra. Based on the 2D spectra, the new
proton resonances at l 1.23 and 0.81 ppm are part of
an aluminium alkoxide absent in the mixture of 5 and
MAO. In fact, there existed a weak ROE correlation
between the proton signals at l 0.81 and −0.40 ppm.
Similarly, the two Cp proton resonances (l 5.88 and
6.03 ppm) initially appeared in the ratio 5:1 but later
1
the H resonance for the pure Cp2ZrCl2 at l 5.88 ppm
1
However, the connectivities between the other new H
became barely visible. Hence, the added Cp2ZrCl2
seems to direct the equilibrium favouring the formation
of a certain aluminium alkoxide and simultaneously
diminishing the amount of the free alkenol 4 in the
tri-component system. The participation of Cp2ZrCl2 in
the observed change in component equilibria is further
supported by a weak ROE correlation detected between
the t-Bu protons (l 1.00 ppm) of 4 and the Cp protons
at l 6.03 ppm. The observed ROE correlation and the
shifted l-value of Cp protons (6.03 ppm, DlH=0.15
ppm compared to Cp2ZrCl2) suggest a coordination
between the comonomer oxygen atom and zirconium in
the reaction mixture.
signals appearing at l 0.75 and −0.25 ppm could not
be deduced from the 2D spectra. Pure Cp2ZrCl2 (lH
5.88 and lC 116.1 ppm) along with the formed
Cp2ZrCH3Cl species (Cp lH 5.74, lC 112.9 ppm; CH3
lH 0.36, lC 32.1 ppm) were present in equal amounts.
The interaction of zirconocene with MAO could induce
the new species observed. In all the studied component
The 1-CH3/21-CH3 and 31-CH3/32-CH3 signals of t-
alkenol 5 were assigned at l 1.03 and 0.85 ppm (Fig.
6(A)). The addition of MAO produced multiple CH3
signals appearing at separate l values (Fig. 6(B)). Based
on the 2D spectral analysis the different 31-CH3/32-CH3
and 1-CH3/21-CH3 resonances were assigned as being
part of three distinct molecular fragments formed in the
ratio 1:1:8. The methyl groups exhibited strong ROE
correlations to the Al–CH3 signals at l −0.22, −0.23
and −0.27 ppm indicating the presence of aluminium
alkoxides of which the main component has the chemi-
Scheme 3. The structures of (top) 10-undecenyl methyl ether (6),
(middle) 10-undecenyl trimethylsilyl ether (7) and (bottom) 12-tride-
cen-2-yl trimethylsilyl ether (8).

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
171
Table 2
Characteristic chemical shift values (l, ppm) for mono-, bi- and tri-component mixtures of ethers 6–8 measured in toluene-d8
a
Compound number
Atomic number
Ether derivative
Ether derivative with MAO or MAO/Cp2ZrCl2
1H l (ppm)
13C l (ppm)
1H l (ppm)
13C l (ppm)
6
7
8
1
2
3.16 (s)
3.22 (t)
58.3
73.0
3.15 (s)
3.23 (t)
58.3
73.0
1
2
3.53 (t)
1.52 (m)
62.7
33.3
3.60 (t)
1.56 (m)
65.6
32.4
1
2
1.12 (d)
3.70 (m)
24.3
68.7
1.15 (d)
3.86 (m)
23.1
71.1
a Multiplicity (m) of the observed NMR signal is given in parentheses. The atomic number refers to Scheme 3.
1
mixtures of 5 the H and 13C resonances for 12-CH2,
13-CH and 14-CH2 appeared at l 2.00, 5.80 and 5.00
ppm and at l 34.3, 139.3 and 114.5 ppm, respectively.
These resonances did not show HMBC or ROE corre-
lations to the resonances of catalyst system.
when Cp2ZrCl2 was added to the mixture of 8 and
MAO (Fig. 7). Based on the 2D spectral analysis, these
1H signals were assigned to four different fragments
with hydrocarbon chains (Scheme 4). The most abun-
dant species formed was the dimer I. Three methyl-sub-
stituted fragments II, III and IV were present to a lesser
extent in the intensity ratio 2:1:1.
2.2. Reactions of ether deri6ati6es with the MAO–
Cp2ZrCl2 catalyst system
Similar behaviour was observed when 7 or 1-un-
decene were allowed to react with the MAO–Cp2ZrCl2
catalyst. The former required a reaction time of some
weeks in an NMR tube, the latter reacting immediately.
Compound 6 did not produce fragments of the types
I–IV even with a prolonged reaction time. Previously,
some amino functionalized monomers have been re-
ported to form type I dimers in homopolymerizations
with borane-activated zirconocene catalysts [28].
Based on the 2D spectral analysis, the ether deriva-
tives 6–8 (Scheme 3) remained mainly as free
comonomers in the presence of MAO. The characteris-
1
tic H and 13C resonances of 6–8 in different compo-
nent mixtures are given in Table 2. For 6 a transient
HMBC correlation was found between a 13C resonance
1
at lC 50.7 ppm (lH 3.10 ppm, s) and a H singlet at lH
−0.62 ppm (lC −10.9 ppm). Apparently a minor part
of 6 existed as a complex with MAO as previously
described [16]. Slightly shifted l values of 1-CH2/2-CH2
and 1-CH3/2-CH were determined for 7 and 8, respec-
tively. However, these signals did not exhibit HMBC or
ROE correlations to the several H resonances appear-
ing at l −0.35 to −0.65 ppm in the spectrum of 7 or
8 and MAO.
2.3. Reactions of carbonyl deri6ati6es with the MAO–
Cp2ZrCl2 catalyst system
Slightly altered chemical shift values, DlH=0.1;
DlC=1.4 and DlC=3.2, were obtained for 1-CH3 and
2-CꢀO resonances of compound 9 (Scheme 5) in the
1
The CH2ꢀCH–CH2 resonances of 6–8 were not ob-
served to deviate from their original chemical shift
values (l(H) 5.00, 5.80 and 2.00 ppm) in the presence
of MAO. A completely new set of olefinic 1H reso-
nances emerged in the spectral region l 4.70–5.50 ppm
Scheme 4. Structures and chemical lH,C values in ppm (13C in
parentheses) of the four assigned fragments formed in a mixture of 8,
MAO and Cp2ZrCl2.
Fig. 7. The 1H-NMR spectrum (300 MHz) of 8, MAO and Cp2ZrCl2.

172
T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
Table 3
Characteristic chemical shift values (l, ppm) for mono-, bi- and
tri-component mixtures of carbonyl derivatives 9–11 measured in
a
toluene-d8
Compound
number
Atomic
number
1H l (ppm)
13C l (ppm)
9
1
3.40 (s), [3.30
(s)]
50.8 [52.2]
2
3
4
173.2 [176.4]
34.2
25.3
2.10 (t)
1.50 (m)
10
11
1, 21, 22
3
4
5
1.40 (s)
28.2
172.3 [173.0]
35.7
Scheme 5. Structures of the carbonyl derivatives: methyl decenoate
(9), t-butyl undecenoate (10) and 2,2-dimethyl-11-dodecen-3-one (11).
2.10 (t)
1.54 (m)
25.5
1, 21, 22
3
4
5
0.97 (s)
26.4
213.0
36.3
presence of MAO or MAO/Cp2ZrCl2 (Table 3). Proton
singlets at l 3.12 (lC 50.3 ppm) and 3.08 (lC 48.6 ppm)
ppm were also observed as well as Al–CH3 resonances
at l −0.28 to −0.65 ppm (lC −7.0 to −10.0 ppm).
Cp2Zr(Me)Cl and another zirconocene species (lH 5.92
ppm, lC 115.1 ppm) appeared in the tri-component
2.17 (t)
1.56 (m)
24.3
a Multiplicity of the observed NMR signal is given in parentheses.
The l values given in brackets are measured in the presence of MAO
or MAO/Cp2ZrCl2. The numbering of the H and C atoms refers to
Scheme 5.
1
mixture. However, the H-13C correlations over two or
more bonds connecting the observed signals to 9 were
not detected.
The other two carbonyl derivatives investigated, t-
butyl ester 10 and ketone 11 in Scheme 5, produced
unsaturated species in their reactions with MAO. An
alkene fragment V was identified as a reaction product
of 10 and MAO (Scheme 6). A partial decomposition of
10 to free 10-undecenoic acid had occurred involving an
alkyl–oxygen cleavage to produce a t-butyl cation un-
der Lewis acidic conditions. The formed t-butyl cation
reacts further with MAO through rearrangement(s) and
elimination to produce V. A coupling constant of 1.1
Hz was measured for the CH3 (d) and CH (septet)
protons. The l-values of fragment V and a weak NOE
correlation detected between the CH and Al–CH3 (l
−0.40 ppm) protons suggest that an aluminium species
(AlXMe) is coordinated to V.
of 10 and MAO noticeably. Monomethyl derivative
Cp2ZrCH3(Cl) was formed in a ratio 1:1 to Cp2ZrCl2.
1
Similar to compound 9, the characteristic H and 13C
signals of unreacted 10 appeared in the NMR spectra
measured from the bi- or tri-component mixtures
(Table 3).
Two unsaturated fragments with slightly different
chemical shift values were formed in a reaction of
ketone 11 and MAO in a ratio 1:2 compared to free 11
(Scheme 7). The t-Bu, H1 and H2 protons of each
fragment exhibited HMBC correlations to the corre-
sponding quaternary carbon atom (Cq at l 155.4 or
155.7 ppm). Presumably the oligomeric nature of MAO
and the different oxygen–aluminium environments
present in MAO solution induced the altered l values
for the fragment couple. The observed ROE correla-
The addition of Cp2ZrCl2 did not affect the reaction
Scheme 6. Chemical lH,C values in ppm (13C in parentheses) for fragment V identified in a reaction of 10 with MAO (AlXMe=an aluminium
species).

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
173
Scheme 7. Chemical lH,C values in ppm for the assigned fragments formed in a reaction of 11 with MAO. The superscripts a and b refer to H
and C atoms being part of the same fragment.
tions from the Al–CH3 centred at l −0.36 ppm to the
bH1, bH2 and bt-Bu protons support this conclusion.
Strong ROE correlations between the t-Bu (l 1.15 and
1.12 ppm) and the methine protons (l 4.87 and 4.83
ppm) as well as the absence of the correlation between
the t-Bu protons and methylene protons (l 2.25 and
2.16 ppm) indicate that the formed vinyl ethers exist in
the Z configuration (Scheme 7, Fig. 8).
The addition of Cp2ZrCl2 did not have any immedi-
ate observable effect on the product formation. The Cp
protons of different zirconocene species appeared at l
5.76 (lC 112.5), 5.83 (lC 111.2), 5.88 (lC 115.7) and
Fig. 8. The expanded ROESY spectrum (500 MHz) of 11, MAO and Cp2ZrCl2. The broken line contours are TOCSY and unbroken ROE
correlations.

174
T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
6.03 (lC 114.3) ppm in an equal intensity ratio. The two
former Cp signals disappeared and the two latter re-
mained in a ratio 1:10 due to the aging of the NMR
sample. Simultaneously, two triplets had emerged at l
4.29 and 4.43 ppm in a ratio 8:1. Each of them exhib-
ited a ROE correlation to a new t-Bu proton signal at
l 1.14 or 1.18 ppm, respectively (Fig. 8). The t-Bu
signals exhibited ROE correlations to the spectral re-
gion l −0.26 to −0.44 ppm. Accurate l values could
not be determined due to the overlapping of the corre-
sponding Al–CH3 signals. The lower chemical shift
values of the two methine proton resonances (ca. Dl 0.5
ppm) compared to the original l values of H1 reported
in Scheme 7 suggest that X is part of a MAO oligomer
with an appropriate electronic surrounding to induce
the observed shift of H1 protons to a higher field.
Presumably the formation of the new unsaturated spe-
cies has occurred via the zirconocene at l 6.03 ppm.
3. Experimental
3.1. Preparation of MAO and NMR samples
MAO in toluene-d8 (Aldrich 99+%D) solution
(MAO) was prepared from Al2(SO4)3*18H2O and TMA
according to the standard procedure [24]. The alu-
minium content of MAO prepared was estimated to be
5.8 wt.%. Its effectivity was tested by homopolymeriz-
ing ethene with a zirconocene-based catalyst and com-
paring the activity with a commercial MAO in toluene
solution. The prepared MAO activated the metallocene
catalyst as well as the commercial MAO. All NMR
samples were prepared under nitrogen in a glove box.
The evolution of gas was observed while adding MAO
into the toluene-d8 solutions of alkenols 1–5. Conse-
quently, the 1H resonance at ca. l 0.23 ppm at-
tributable to methane [2] was detected at the spectra
measured from the bi- and tri-component mixtures of
1
1–5. The aforementioned H signal also appeared at
the spectra of 6–11 and MAO or MAO/Cp2ZrCl2. The
two- and three-component reaction mixtures in toluene-
d8 were studied in 5 mm NMR tubes specially designed
for sealing. The tubes were closed with NMR-tube
Tip-Off Manifold (Wilmad) and sealed outside the
glove box using a butane flame. The sample volumes
were 0.7 ml and concentrations of samples were 0.07–
0.42 M. In each sample the mole ratio of the alkene
derivative and MAO is 1:1 the amount of Cp2ZrCl2
being catalytic (ca. 5 mg).
2.4. Comparison of the NMR and copolymerization re-
sults
The oxygen functionalized alkenes 1,3,6–11 and a
t-alkenol, 2,2-dimethyl-3-(1,1-dimethylethyl)-11-dode-
cen-3-ol) synthesized according to the literature [29],
have been tested as comonomers in zirconocene–MAO
catalysed copolymerizations with ethene or propene
[20–23]. The activity of the catalyst system was sup-
pressed to varying degrees depending on the functional
group of polar comonomer and the steric hindrance
around the hetero atom. The NMR studies suggest that
stronger interaction between comonomers and the cata-
lyst system is involved in the case of a- or b-branched
rather than straight chain alkenols. In fact, the decom-
position of the aluminium alkoxide was observed only
for the straight chain alkenol 1. Presumably the
stronger bond or coordination of the Lewis acidic Al to
the free electron pair of oxygen reduces the deleterious
interactions between a comonomer and active catalyst
centres. Moreover, the bond formation between alu-
minium and comonomer oxygen is not a prerequisite
for the diminished catalyst fouling, since equal catalyst
activity has been found in copolymerizations of the
OMe or OTMS derivatives 6 and 7 compared to 1 [30].
The carbonyl compounds 9–11 deactivated the cata-
lyst more strongly than the alkenols or ether derivatives
indicating the different interaction of a CO2R or CꢀO
group with the catalyst system. This deactivation might
be caused by the presence of mainly free comonomer in
the polymerization reaction, or alternatively by the
formation of some other unsaturated species as de-
tected by NMR. The latter were also observed in the
1H-NMR spectrum recorded from the copolymerization
product of ethene and 10.
3.2. Measurement of NMR spectra
1
The H and 13C spectra were referenced to the sol-
vent (1H l 2.10 ppm for residual CHD2 and 13C l 20.4
ppm resonances of toluene-d8) measured with te-
tramethylsilane (TMS) added into an unsealed NMR
1
tube. All the samples were measured at 27°C. The H-,
13C- and 2D-NMR measurements (HSQC, HMBC,
ROESY (or TROESY) and NOESY) were recorded on
a Varian Unity 500 MHz (1, 4, 5 and 11(ROESY)) or
a Varian Inova 300 MHz spectrometer (1–11) using
1
Varian standard pulse sequences. The H spectra of 2
and 3 were also measured on a Varian Unity 600 MHz.
In the HSQC and HMBC experiments the coherence
selection was obtained using pulsed field gradients
along the Z direction. In 2D experiments the data of
the indirect dimension were zero filled to be 2×number
of acquired data increments. In phase-sensitive experi-
ments (HSQC, ROESY and NOESY) a p/2 shifted
sine-bell window weighting function were applied in F1
and F2 dimensions. The number of collected transients
were 16–64 and time increments 256–512 in 2D exper-
iments. In the ROESY and NOESY 100–200 ms mix-
ing times and acquisition time of 0.18 s were used. In
the former, the spin lock was generated using a

T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
175
DANTE-type pulse sequence. The acquisition times in
the HSQC and HMBC were 0.11 and 0.22 s, respec-
tively. In the HMBC experiments, non-shifted sine-bell
window weighting functions were used in both dimen-
sions. A relaxation delay of 1 s was used in all
experiments.
1.52 (m, 2H), 1.42–1.16 (12H); 13C (l ppm): 139.3,
114.5, 73.0, 58.3, 34.3, 30.3, 30.1, 30.0, 29.9, 29.6, 29.4,
26.7; HRMS Calc. for C12H24O 184.1827, Found
184.1823.
1
Data for compound 7: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 3.53 (t, 2H), 1.98 (m, 2H), 1.52 (m, 2H),
1.42–1.16 (10H), 0.12 (s, 9H); 13C (l ppm): 139.3,
114.5, 62.7, 38.3, 34.3, 33.3, 30.1, 30.0, 29.6, 29.4,
26.4,–0.38; HRMS Calc. for C14H30OSi 242.2066,
Found 242.2055.
3.3. Origin and spectral data for functionalized alkenes
1-Undecene (received from Fluka) was used as a
model compound for a reaction of a non-functionalized
alkene with the MAO–Cp2ZrCl2 catalyst system. The
commercial 10-undecen-1-ol 1 was received from Fluka
and compound 9 was synthesized by Neste. Com-
pounds 2-5 were synthesized as previously reported
[31]. Compounds 6 [32], 7–8 [33], 10 [34], and 11 [29]
were prepared according to known literature
procedures.
1
Data for compound 8: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 3.70 (m, 1H), 2.00 (m, 2H), 1.50–1.20
(16H), 1.12 (d, 3H), 0.14 (s, 9H); 13C (l ppm): 139.3,
114.5, 68.7, 40.2, 34.3, 30.3, 30.2, 30.1, 30.0, 29.7, 29.5,
26.4, 24.3, 0.43; EI (70 eV): m/z 170.
1
Data for compound 9: H (l ppm): 5.75 (m,1H), 5.00
(m, 2H), 3.40 (s, 3H), 2.10 (t, 2H), 1.94 (m, 2H), 1.50
(m, 2H), 1.32–1.10 (8H); 13C (l ppm): 173.2, 139.2,
114.5, 50.8, 34.2, 34.1, 29.6, 29.5, 29.4, 29.3, 25.3.
Compounds 2–11 were purified by the usual chro-
matographic techniques or vacuum distillation prior to
the NMR sample preparation. All the compounds stud-
ied were stored under molecular sieves. The following
1H- and 13C-NMR data were recorded for compounds
1–11 with a Varian Inova 200 or 300 MHz spectrome-
ter using toluene-d8 as a solvent. Mass spectra as well as
high-resolution mass spectra were recorded on a JEOL
JMS-SX102 with an EI potential of 70 eV.
1
Data for compound 10: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 2.10 (t, 2H), 1.97 (m, 2H), 1.54 (m, 2H),
1.40 (s, 9H), 1.36–1.14 (10H); 13C (l ppm): 172.3,
139.2, 114.5, 79.2, 35.7, 34.3, 29.8, 29.7, 29.5, 29.4, 28.2,
25.5; EI (70 eV): m/z 240.
1
Data for compound 11: H (l ppm): 5.77 (m, 1H),
5.00 (m, 2H), 2.17 (t, 2H), 1.98 (m, 2H), 1.56 (m, 2H),
1.40–1.10 (10H), 0.97 (s, 9H); 13C (l ppm): 213.0,
139.2, 114.5, 43.8, 36.3, 34.2, 29.9, 29.7, 29.5, 29.4, 26.4,
24.3; HRMS Calc. for C14H26O 210.1984, Found
210.1993.
1
Data for compound 1: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 3.45 (t, 2H), 2.00 (m, 2H), 1.40 (m, 2H),
1.38–1.20 (13H); 13C (l ppm): 139.3, 114.5, 62.7, 34.3,
33.3, 30.2, 30.1, 30.0, 29.7, 29.4, 26.3.
1
Data for compound 2: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 3.13 (s, 2H), 2.00 (m, 2H), 1.50–1.10
(15H), 0.83 (s, 6H); 13C (l ppm): 139.3, 114.5, 71.7,
39.2, 35.2, 34.3, 31.2, 30.3, 30.2, 30.1, 29.7, 29.5, 24.4,
24.1; HRMS Calc. for C15H30O 226.2297, Found
226.2299.
4. Conclusions
Based on the H- and 13C-NMR measurements in-
1
cluding HSQC, HMBC, ROESY and NOESY experi-
ments, interaction mechanism(s) between an oxygen
functionalized alkene with an MAO–Cp2ZrCl2 catalyst
exhibited a clear dependence on the nature of the
functional group and on the steric hindrance around
the hetero atom. Hydroxyl functionalized alkenes 1–5
formed alkoxides with MAO even in the presence of
C(CH3)3 and C(CH3)2 groups a to the OH group. On
the contrary, their OMe or TMS derivatives (6–8)
remained mainly as free comonomers in the presence of
MAO. For compound 6 an HMBC correlation indicat-
ing a partial coordination to MAO was detected. a- or
b-branching to the OH group of an alkenol induced the
formation of several aluminium alkoxides. On the other
hand, the highly sterically hindered 4 and the straight
chain alkenol 1 formed one main species with MAO.
Apparently a moderate degree of branching allows the
formation of aluminium alkoxides from structurally
different MAO oligomers.
1
Data for compound 3: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 3.58 (m, 1H), 2.00 (m, 2H), 1.50–1.20
(17H), 1.05 (d, 3H); 13C (l ppm): 139.3, 114.5, 67.7,
39.9, 34.3, 30.3, 30.2, 30.1, 30.0, 29.7, 29.5, 26.3, 23.8;
HRMS Calc. for C13H26O 198.1984, Found 198.1988.
1
Data for compound 4: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 2.95 (s, 1H), 2.01 (m, 2H), 1.56 and 1.22
(m, 2H), 1.42–1.26 (15H), 1.00 (s, 9H), 0.96 (s, 6H); 13
C
(l ppm): 139.1, 114.5, 83.7, 42.5, 40.1, 37.6, 34.3, 31.4,
30.3, 30.2, 30.1, 29.7, 29.5, 29.1, 26.0, 25.6, 24.6;
HRMS Calc. for C19H38O 282.2923, Found 282.2909.
1
Data for compound 5: H (l ppm): 5.80 (m, 1H),
5.00 (m, 2H), 2.00 (m, 2H), 1.44–1.20 (17H), 1.03 (s,
6H), 0.85 (s, 6H); 13C (l ppm): 139.3, 114.5, 74.9, 40.0,
37.4, 34.3, 31.5, 30.4, 30.3, 30.1, 29.7, 29.5, 25.6, 25.3,
21.6; HRMS Calc. for C17H34O 254.2609, Found
254.2599.
1
Data for compound 6: H (l ppm): 5.80 (m, 1H),
Zirconocene seemed to enhance the interaction be-
tween an alkenol and MAO since additional aluminium
5.00 (m, 2H), 3.22 (t, 2H), 3.16 (s, 3H), 2.00 (m, 2H),

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T. Helaja et al. / Journal of Organometallic Chemistry 579 (1999) 164–176
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alkoxides were detected in the tri-component mixtures.
A more pronounced effect of zirconocene was observed
in the reaction of TMS derivative 8 which produced
dimers of the type CH2ꢀCR1R2 along with methylated
derivatives CH2ꢀC(Me)(R) and (Me)CHꢀCH(R) (R,
R1, R2=hydrocarbon chain) with the catalyst system.
Compound 7 and 1-undecene reacted analogously, the
former being the least reactive.
Compound 10 was partly decomposed to
Me2CꢀCH–Al–X species in its reaction with MAO or
MAO/Cp2ZrCl2. Two unsaturated CH2ꢀCH(CH2)5CH2
CHꢀC(t-Bu)O–Al(CH3)–X species with slightly differ-
ent chemical shift values were assigned in the reaction
of ketone 11 with MAO. Additional similar fragments
emerged in the tri-component mixture of 11. Obviously
1
the characteristic H and 13C resonances of the four
fragments appear at different l values due to the X
being part of a different MAO oligomer.
In all the studied tri-component mixtures the olefinic
part of comonomers were found not to interact directly
.
with Cp2ZrCl2 or other zirconocene species formed in
the component mixture. An ROE correlation between
the olefinic protons of sec alkenol 3 or 4 and methyl
protons of MAO was observed, suggesting coordina-
tion of the CꢀC of 3 or 4 to MAO. A more precise
structure could not be deduced on the basis of the
measured spectra. The nature of interaction appears to
be rather weak since the chemical shift values for
CH2ꢀCH did not alter compared to the corresponding
lH values of free 3 or 4. Hence, only limited informa-
tion about the structure of aluminium fragments coor-
dinated or attached to comonomers could be obtained
by the utilized solution NMR techniques. By compar-
ing ROESY with NOESY measurements, the observed
ROE correlations were always detected as NOEs with
positive signs. Thus the molecular weights of formed
species were clearly below 1000 g mol−1 based on the
molecular correlation times [35].
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Acknowledgements
[30] K. Hakala, B. Lo¨fgren, T. Helaja, in preparation.
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This work was supported by the Neste Foundation.
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