A study of representative alcohol, alkoxide, thiol and thiolate complexes of B(C6F5)3; Their roles as activators of zirconocene olefin polymerization initiators

Article abstract of DOI:10.1016/S0020-1693(02)00836-8

The highly electrophilic borane B(C₆F₅)₃ reacts with n-octadecanol (n-C₁₈H₃₇OH) and n-octadecanethiol (n-C₁₈H₃₇SH) to form equilibrium mixtures of reactants and the 1:1 adducts (n-C₁₈H₃₇EH)B(C₆F₅)₃ (E=O, S); equilibrium constants for adduct formation are determined. The adducts are deprotonated by 1,8-bis(dimethylamino)naphthalene (proton sponge) to form the salts [C₁₀H₆(NMe₂)₂H][(n-C ₁₈H₃₇O)B(C₆F₅)₃] and [C₁₀H₆(NMe₂)₂H][(n-C ₁₈H₃₇S)B(C₆F₅)₃], respectively, and by Cp₂ZrMe₂ to give methane and, apparently, the unstable zirconium complexes [Cp₂ZrMe][(n-C₁₈H₃₇E)B(C₆F ₅)₃]. The alcohol, alkoxide, thiol and thiolate systems are characterized in solution by ¹H, ¹⁹F, ¹³C{¹H} and ¹¹B NMR spectroscopy and in the solid state by FAB mass spectrometry, and it is also shown that proton sponge can coordinate in monodentate fashion to B(C₆F₅)₃.

Full text of DOI:10.1016/S0020-1693(02)00836-8

Inorganica Chimica Acta 335 (2002) 43ꢁ51
/
www.elsevier.com/locate/ica
A study of representative alcohol, alkoxide, thiol and thiolate
complexes of B(C6F5)3; their roles as activators of zirconocene olefin
polymerization initiators
Mark J. Drewitt, Martina Niedermann, Rajesh Kumar, Michael C. Baird *
Department of Chemistry, Queen’s University, Kingston, Ont., Canada K7L 3N6
Received 1 October 2001; accepted 24 December 2001
Abstract
The highly electrophilic borane B(C6F5)3 reacts with n-octadecanol (n-C18H37OH) and n-octadecanethiol (n-C18H37SH) to form
equilibrium mixtures of reactants and the 1:1 adducts (n-C18H37EH)B(C6F5)3 (EꢀO, S); equilibrium constants for adduct
/
formation are determined. The adducts are deprotonated by 1,8-bis(dimethylamino)naphthalene (proton sponge) to form the salts
[C10H6(NMe2)2H][(n-C18H37O)B(C6F5)3] and [C10H6(NMe2)2H][(n-C18H37S)B(C6F5)3], respectively, and by Cp2ZrMe2 to give
methane and, apparently, the unstable zirconium complexes [Cp2ZrMe][(n-C18H37E)B(C6F5)3]. The alcohol, alkoxide, thiol and
1
thiolate systems are characterized in solution by H, 19F, 13C{1H} and 11B NMR spectroscopy and in the solid state by FAB mass
spectrometry, and it is also shown that proton sponge can coordinate in monodentate fashion to B(C6F5)3. # 2002 Published by
Elsevier Science B.V.
Keywords: Borate complexes; Alkoxide complexes; Thiolate complexes; Olefin polymerization
1. Introduction
Recent years have seen huge advances in the devel-
opment of wellꢁdefined, cationic substituted cyclopen-
/
ð2Þ
tadienyl (Cp?) complexes of the Group 4 metals as
alkene polymerization catalysts [1]. In the most studied
catalyst systems, the active species are generated from
neutral metallocene precursors as in Eqs. (1) and (2),
reactions which involve the abstraction of methyl
carbanions from the metals by B(C6F5)3 and trityl ion,
respectively.
The methylborate anion of Eq. (1) coordinates
relatively strongly to the electron deficient cations, and
the dissociation postulated is evidenced only from the
chemistry of the complexes formed. In contrast, the
tetrakis(pentafluorophenyl)borate anion of Eq. (2)
forms such weakly associated ion pairs that the equili-
brium shown lies well toward the dizirconium species.
Again, however, the chemistry of the complexes formed
ꢂ
ð1Þ
?
implies the ready availability of [Cp2ZrMe] [1]. Of
course, in order for an initiator system to exhibit high
activity, the monomer must be able to coordinate
readily. Since this generally involves accessing the
ꢂ
?
putative 14-electron intermediate [Cp2ZrMe] by dis-
placement of the counteranions, considerable attention
has been paid to determining the coordinating abilities
of anionic species such as [MeB(C6F5)3]ꢃ and
[B(C6F5)4]ꢃ, and correlating their ease of dissociation
with catalyst activities [2].
* Corresponding author. Tel.: ꢂ
6669.
E-mail address: bairdmc@chem.queensu.ca (M.C. Baird).
/
1-613-533 2616; fax: ꢂ1-613-533
/
0020-1693/02/$ - see front matter # 2002 Published by Elsevier Science B.V.
PII: S 0 0 2 0 - 1 6 9 3 ( 0 2 ) 0 0 8 3 6 - 8

44
M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ51
/
Considerable research has also been carried out in
shown in Eq. (4) even in the absence of B(C6F5)3 [10].
?
Thus, in a solution containing e.g. Cp2ZrMe2, an
alcohol and B(C6F5)3, one wonders what species might
actually be present.
We describe here the results of an investigation of the
solution chemistry, in the presence and absence of base,
of Brønsted acidic alcohol (n-octadecanol, n-
C18H37OH) and thiol (n-octadecanethiol, n-C18H37SH)
adducts of B(C6F5)3. Anticipating further investigations
efforts to design new anions which are even more weakly
coordinating than those mentioned above [3]. The
approaches are generally based on the premise that
delocalization of negative charge over as many atoms as
possible in a large anion will be of advantage, and a wide
variety of anionic species has been reported [3]. In
metallocene catalyst chemistry, the synthetic methodol-
ogies have often involved modification of the borate
anion of Eq. (1), for instance, by substitution of the
groups on boron by more complex fluoroaryl groups
[2d,2e,4]. The bulkier anions do indeed coordinate less
well than does [MeB(C6F5)3]ꢃ, and form more active
catalysts.
?
of the adducts as co-initiators, with Cp2ZrMe2, for
alkene polymerization, we have also studied reactions of
the alcohol and alcohol adducts in solution with
Cp2ZrMe2. The high molecular weight, long chain n-
octadecanol and n-octadecanethiol were chosen in part
because measuring of millimole quantities would be
more accurate than with low molecular weight analo-
gues, in part with the expectation that ionic species of
the type formed in Eq. (4) might exhibit better solubi-
lities and hence more useful catalytic properties in non-
polar solvents.
An alternative and rather simpler procedure synthe-
tically involves the interaction of B(C6F5)3 with various
anions Xꢃ (Xꢃ ꢀe.g. OHꢃ [5], CNꢃ [2f,6], N3 [6b],
/
ꢃ
ORꢃ [5b,5c,5d,5k], SRꢃ [5b,5c,5d]-imidazolate [7]) to
form complex anions of the types [XB(C6F5)3]ꢃ and [(m-
X){B(C6F5)3}2]ꢃ. Research on the hydroxyl system has
a long history, and it has been well established that,
because of the strongly electron withdrawing character
of B(C6F5)3, the aqua complex H2OB(C6F5)3 is a strong
Brønsted acid capable of acid cleavage of metal-carbon
bonds as in Eq. (3) [5a,5c,5d,5e].
2. Results and discussion
Cp2?ZrMe2 ꢂH2OB(C6F5)3
2.1. Adduct formation with primary alcohol and thiol
0 [Cp?ZrMe][(HO)B(C6F5)3]ꢂCH4
(3)
2
The adducts of B(C6F5)3 with n-octadecanol (n-
C18H37OH, 1) and n-octadecanethiol (n-C18H37SH, 4)
form rapidly on mixing B(C6F5)3 and n-octadecanol or
n-octadecanethiol in CD2Cl2 or toluene-d8.
There result organometallic complexes, similar to
those shown in Eqs. (1) and (2), which have been shown
to catalyze alkene polymerization [5b,5c,5d,5e]. Coordi-
nation of alcohols ROH (Rꢀalkyl) to B(C6F5)3 simi-
/
B(C6F5)3 ꢂnC18H37EHX(nC18H37EH)B(C6F5)3E
larly gives the 1:1 adducts (ROH)B(C6F5)3 [5b,5c,5d,5k],
and these appear to exhibit sufficiently enhanced acidity
that they also cleave metal-carbon bonds (Eq. (4)) to
give the cationic products which behave as alkene
polymerization catalysts [5b,5c,5d].
ꢀO(2); S(5)
(5)
The adducts have previously been reported by Siedle
et al. [5c,5d], but no characterizing data were presented.
The reactions can, however, be conveniently studied by
NMR spectroscopy using a range of nuclei, 1H, 13C, 11
B
Cp2?ZrMe2 ꢂ(ROH)B(C6F5)3
and 19F, which are highly sensitive to the coordination
and electronic environment. Thus, on adding one molar
equivalent of B(C6F5)3 to a solution of n-octadecanol
0 [Cp?ZrMe][(RO)B(C6F5)3]ꢂCH4
(4)
2
Thus a wide variety of new, readily synthesized
activators containing bulky counteranions is now ap-
parently available. However, few such systems have as
yet been studied in detail, and while crystalline alcohol
adducts of B(C6F5)3 can be isolated from non-polar
solvents such as pentane [5c,5k], in fact little is known of
their solution chemistry. Indeed, 1:1 adducts with a
variety of N- [5k,8a] O- [5k,8b] and P-donors [8c] exhibit
relatively small association constants and high labilities,
(ꢀ1 mM) in CD2Cl2, the OH resonance shifted from d
/
1.38 (m) to d 6.19 (broad singlet), indicating significant
exchange of coordinated alcohol with, presumably, a
small amount of free n-octadecanol remaining in solu-
tion under these circumstances (see below). Similarly the
OCH2 1H and OCH2 13C{1H} resonances shifted from
3
d 3.58 (triplet, JHH 6.5 Hz) and 63.3 to d 4.02 (triplet,
3JHH 6.9 Hz) and 70.5, respectively. On the addition of
0.1 or greater molar equivalents of B(C6F5)3, however,
the OH resonance changed to a well-resolved triplet and
the OCH2 resonance to a double triplet, suggesting that
the concentration of the free alcohol had been effectively
reduced to the point that exchange was now no longer
observable.
while B(C6F5)3 itself undergoes BÃ
presence of proton sources [8c]. In addition, ZrÃ
bonds are generally stronger than BÃO bonds [9],
/C cleavage in the
/
O
/
leading to the possibility of ligand exchange and the
formation of alkoxy-zirconium compounds, while sim-
ple alcohols can induce the same methyl protonation

M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ
/51
45
The other 1H and 13C resonances shift relatively little,
but the 11B resonance of B(C6F5)3 shifts from d 63.3 to
3.8 and the o-F, m-F and p-F 19F resonances shift from
d ꢃ
and ꢃ
/
129.1, ꢃ
/
162.0 and ꢃ
/
144.7 to d ꢃ
/
134.9, ꢃ
/
168.3
/
164.9, respectively. The changes in the 11B and the
19F NMR spectra are all consistent with change in the
coordination number of the boron from three to four
[5i,8a,11]. Similar changes were observed on the addi-
tion of one molar equivalent of B(C6F5)3 to a solution of
n-octadecanethiol in CD2Cl2, the SH resonance shifting
from d 1.35 (triplet, 3JHH 7.9 Hz) to d 3.35 (triplet, 3JHH
8.0 Hz), the SCH2 1H and SCH2 13C{1H} resonances
shifting from d 2.51 and 65.1 to d 2.54 and 24.9,
respectively. Important NMR data for these systems
are listed in Table 1.
Fig. 1. Plot of the change in chemical shift, Dd, of the OCH2 protons
of n-octadecanol vs. borane concentration.
Since alcohols contain two lone pairs, the 2:1 adduct
{(n-C18H37OH){B(C6F5)3}2 could in principle also form
and play a role in dimethyl zirconocene activation
analogous to the chemistry depicted in Eq. (4). The
stoichiometry of the n-octadecanol reaction was there-
fore determined using the mole ratio method [12]. The
concentration of the n-octadecanol was kept constant
and the ratio with respect to the borane was varied from
0.6:1 to 5:1. The chemical shift of the OCH2 protons of
n-octadecanol was observed using 1H NMR spectro-
scopy, as this is highly sensitive to coordination. The
experimental data are presented as supplementary
information (Table S1) and, as shown in Fig. 1, a plot
of the change in chemical shift, Dd, as a function of
borane concentration resulted in two lines intersecting at
an approximate ratio of 1:1 and well away from the
intersection point for a 2:1 reaction, confirming the
anticipated 1:1 stoichiometry.
the adduct to C6F5H and B(OC18H37)(C6F5)2, but the
decomposition was only on the order of 1ꢁ3% and did
/
not seriously affect the determination of stoichiometry.
Equilibrium constant measurements for the 1:1 complex
were carried out, using the dilution procedure [13], with
solutions sufficiently dilute (7ꢄ
/
10ꢃ4ꢁ
/
2ꢄ
10ꢃ2 mol
/
lꢃ1) that C6F5H did not form. The procedure involved
diluting portions of a standard solution to known
concentrations, x, while monitoring the 1H chemical
shifts of the OCH2 protons of the n-octadecanol. The
data, which are presented as supplementary information
(Table S2), were fitted to Eq. (6) [13]. In Eq. (6), D is the
difference between the observed chemical shift of the
probe protons in the solutions of the 1:1 adduct at
equilibrium and that of the same proton in the free
component, D0 (dcomp
the limiting chemical shift of the probe protons in the
ꢃdfree) is the difference between
/
During this study, some decomposition of the product
was noted at higher B(C6F5)3 to n-octadecanol ratios, a
1
weak H resonance of C6F5H being observed at d 6.96
(m). This observation suggests the partial metathesis of
1:1 adduct and that of the protons in the free component
(d100% comp
lꢃ1) of the 1:1 adduct.
ꢃdfree) and x is the concentration (in mol
/
Table 1
Selected NMR spectroscopy data (d) for 1ꢁ6 in CD2Cl2 and toluene-d8 (EꢀO, S)
/
Data
CD2Cl2
Toluene-d8
1H, EH
1H, ECH2
13C, ECH2
1H, EH
1H, ECH2
13C, ECH2
1
1.38
6.19
3.58
4.02
3.62
2.51
2.54
1.93
63.3
70.5
65.1
24.9
29.4
29.7
0.43
5.93
3.33
3.35
3.07
2.18
2.00
2.41
62.7
67.9
65.3
24.6
29.0
30.3
a
2
3
4
ꢁ/
1.35
3.35
ꢁ/
1.06
2.57
a
5
6
ꢁ/
ꢁ/
B(C6F5)3
57.9
3.8
o-F
m-F
p-F
B(C6F5)3
60.0
3.2
o-F
m-F
p-F
B(C6F5)3
a
ꢃ129.1
ꢃ134.9
ꢃ133.9
ꢃ131.9
ꢃ132.9
ꢃ162.0
ꢃ168.3
ꢃ168.4
ꢃ163.6
ꢃ168.4
ꢃ144.7
ꢃ164.9
ꢃ165.0
ꢃ153.1
ꢃ164.6
ꢃ129.7
ꢃ135.5
ꢃ135.6
ꢃ131.9
ꢃ131.8
ꢃ161.1
ꢃ163.0
ꢃ167.4
ꢃ162.7
ꢃ167.4
ꢃ142.8
ꢃ155.1
ꢃ164.0
ꢃ152.1
ꢃ163.3
2
3
ꢃ2.4
12.9
ꢃ3.1
9.6
a
5
6
ꢃ11.2
ꢃ10.4
a
The chemical shifts noted for 2 and 5 are averages of the chemical shifts of the free and coordinated species. The concentrations used to acquire
these data may be found in Section 3.

46
M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ51
/
All attempts to isolate the pure 1:1 adducts, (n-
C18H37EH)B(C6F5)3 (EꢀO, S) failed, presumably in
/
part because the n-C18H37 chains ensured that oils were
inevitably obtained, in part because of facile dissocia-
tion. Indeed, plots showing the extent of coordination of
both ligands as a function of borane concentration (Fig.
3) indicate that, at 1:1 ratios, there are appreciable
fractions, 0.12 and 0.30, of free n-octadecanol and n-
octadecanethiol, respectively. Thus, as expected, the
presumably hard Lewis acidic borane exhibits a distinct
preference for the relatively hard alcohol.
The equilibrium constants obtained for n-octadecanol
and n-octadecanethiol are similar to those reported by
Piers et al. [8b] for reactions of B(C6F5)3 with a series of
carbonyl compounds in benzene-d6. From the value for
Fig. 2. Plot of D vs. (D/x)1/2
.
Keq, we can derive a value of DG0 of ꢃ
/
20.3 kJ molꢃ1 for
n-octadecanol in CD2Cl2, and ꢃ
/
15.2 and ꢃ
/
14.7 kJ
molꢃ1 for n-octadecanethiol in CD2Cl2 and toluene-d8,
respectively.
DꢀD0-(D=x)1=2(D0=Keq)1=2
(6)
The results are shown in Fig. 2, where the slope (ꢃ
/
1
2
(D0/Keq) ) yields an equilibrium constant Keq of 36009
/
180 molꢃ1 lꢃ1 at 298 K.
The above method for the derivation of Keq relies on
the reliable determination of the chemical shifts of free,
unassociated n-octadecanol. In CD2Cl2, the chemical
shifts of the OH and OCH2 resonances were found to be
concentration dependent above 0.1 mol lꢃ1, indicating
varying amounts of hydrogen-bonding, but not in the
2.2. Deprotonation of (n-C18H37EH)B(C6F5)3 (Eꢀ
S)
/
O,
We can infer from the downfield shifts of the alcohol
OH and thiol SH protons on coordination that the
electron withdrawing power of the B(C6F5)3 induces
significant increases in the alcohol and thiol acid
range 0.1ꢃ
/
3ꢄ
10ꢃ3 mol lꢃ1, where presumably essen-
/
1
tially unassociated, monomeric n-octadecanol molecules
pertained. When the same system was examined in
toluene-d8, however, the chemical shifts of the OH
and OCH2 resonances varied over the entire useful
strengths. In agreement with this deduction, H NMR
spectroscopy showed that while neither n-octadecanol
nor n-octadecanethiol react in CD2Cl2 with the strong,
non-nucleophilic base 1,8-bis (dimethylamino) naphtha-
lene [15] (proton sponge, C10H6(NMe2)2), addition of
one molar equivalent of proton sponge to a 1:1 mixture
of n-octadecanol or n-octadecanethiol and B(C6F5)3
resulted in the rapid formation of the protonated amine
concentration range (0.1ꢁ
/
3ꢄ
10ꢃ3 mol lꢃ1), and thus
/
some degree of molecular association in the form of
hydrogen bonding was apparently present at all con-
centrations. For this reason, neither the stoichiometry
nor the equilibrium constant for the reaction of n-
octadecanol and B(C6F5)3 could be determined in this
solvent.
(d 19.34) and the anion, (Eq. (7), EꢀO, S).
/
The mole ratio analysis was also applied to the n-
octadecanethiol system in CD2Cl2 and toluene-d8 to
ascertain the stoichiometry; in contrast to the n-octade-
canol-borane system, decomposition of the adduct to
C6F5H was not observed at high borane to n-octadeca-
nethiol ratios (5ꢁ20:1). The data again indicated a 1:1
/
stoichiometry, and this was confirmed using the pro-
gram EQNMR by modeling the 2:1 and 1:1 cases [14]. The
thiol proton was observed throughout the whole range
of B(C6F5)3:n-octadecanethiol ratios, 20:1ꢁ1:5. No ex-
/
change of this proton was observed, as in the case of n-
octadecanol, allowing us to use this as a probe to
measure Keq in CD2Cl2 and toluene-d8. The program
EQNMR was used in this case to extract Keq giving values
Fig. 3. Plots showing fraction of free and complexed n-octadecanol
and n-octadecanethiol, (both 1.75ꢄ
10ꢃ2 mol lꢃ1 initial concentra-
tion), as a function of increasing borane concentration in CD2Cl2.
of 4629
/
30 and 3709
30 molꢃ1 lꢃ1 at 298 K in CD2Cl2
/
/
and toluene-d8, respectively.

M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ
/51
47
The
compounds
[C10H6(NMe2)2H][(n-
O, S) could not be character-
ð7Þ
C18H37EH)B(C6F5)3] (Eꢀ
/
ized satisfactorily by elemental analyses as apparent
inclusion of free alcohol or thiol could seemingly not be
avoided. However, they were readily characterized by
fast atom bombardment (FAB) mass spectrometry, the
positive ion of both being confirmed as the protonated
In the case of n-octadecanol, 1H and 19F NMR
spectroscopy indicated that conversion to the cation
and anion was rapid and quantitative, and the product
was obtained in 84% isolated yield (see Section 3). As
anticipated, deprotonation of the 1:1 adduct results in
upfield shifts of the OCH2 1H and OCH2 13C reso-
nances, by 0.40 and 5.4 ppm, respectively. The 11B and
19F chemical shifts also change, as indicated in Table 1.
Similar results were obtained in CD2Cl2 with the thiol,
the SH resonance disappearing and being replaced by
the NH resonance at d 19.34. There were complemen-
tary shifts of the SCH2 1H and SCH2 13C resonances, as
well as of the 11B and 19F resonances (Table 1), and the
product was obtained in 48% isolated yield (see Section
3).
proton sponge ion, [C10H6(NMe2)2H]ꢂ (FABꢂ
m/e
/
215.3), the molecular ions of [(n-C18H37O)B(C6F5)3]ꢃ
and [(n-C18H37S)B(C6F5)3]ꢃ also being observed at m/e
values of 781.1 and 797.2, respectively.
Interestingly, addition of excess borane to a solution
of [C10H6(NMe2)2][(n-C18H37S)B(C6F5)3] in CD2Cl2
resulted in changes of the chemical shifts of the 1H
NMR and 19F resonances. The changes were small,
1
generally B
/
1 ppm in the H NMR spectra, but the 19F
resonances of the anion and the free borane were
averaged, suggesting a facile equilibrium between [(n-
C18H37S)B(C6F5)3]ꢃ and the 2:1 species [(n-
C18H37S){B(C6F5)3}2]ꢃ. Similar observations were not
made with the n-octadecanol system, possibly because
the smaller oxygen cannot accommodate two borane
molecules.
The lowered isolated yield may come about in part
because a small portion of the proton sponge coordi-
nates in an unusual monodentate fashion to the borane.
1
A H NMR spectrum of a 1:1:1 ratio of thiol, proton
sponge and B(C6F5)3 in CD2Cl2 at 298 K revealed, in
addition
to
the
expected
resonances
of
2.3. Reactions between Cp2ZrMe2 and n-octadecanol
[C10H7(NMe2)2][(n-C18H37S)B(C6F5)3], a set of weak
resonances tentatively attributable to the 1:1 adduct
[(C10H6(NMe2)2)B(C6F5)3]. While the latter has not
been isolated, the 1H NMR spectrum clearly shows
that both planes of symmetry of the proton sponge
framework have been lost. Thus there are six single-
The reaction of Cp2ZrMe2 with an equivalent of n-
octadecanol in CD2Cl2 at ꢃ50 8C resulted in the
/
formation of methane (d 0.18) and, apparently, two
1
new Cp-zirconium compounds. A H NMR spectrum
run immediately showed, in addition to the resonances
of unreacted n-octadecanol and Cp2ZrMe2, two new Cp
hydrogen aromatic resonances at d 7.39 (d, Jꢀ
7.21 (‘t’, Jꢀ8.0 Hz), 7.11 (d, Jꢀ7.8 Hz), 7.02 (‘t’, Jꢀ
8.1 Hz), 6.58 (d, Jꢀ7.5 Hz) and 6.30 (d, Jꢀ7.5 Hz), in
addition to a broad, six-hydrogen methyl resonance at d
2.33 and two three-hydrogen methyl resonances at d
2.54 and 2.61. Thus the structure would appear to be as
/
7.2 Hz),
/
/
/
resonances at d 5.92 and 5.98, two apparent ZrÃ
/
Me
/
/
resonances at d ꢃ0.094 and ꢃ0.17 and a triplet OCH2
/
/
resonance at d 3.76. On warming to 20 8C, the NMR
spectrum indicated that the reaction had proceeded
further, but the resonances of Cp2ZrMe2 and n-octade-
canol were still present. On prolonged standing at
20 8C, the spectrum became very complicated. Reaction
in A, with the NÃ
/B bond more or less perpendicular to
the C10H6 plane.
of Cp2ZrMe2 with 0.5 equiv. of n-octadecanol at ꢃ50
/
8C resulted in little reaction after 10 min, but reaction of
Cp2ZrMe2 with 2 equiv. of n-octadecanol at 20 8C
resulted in immediate disappearance of the resonances
of the Cp2ZrMe2 and the appearance of the resonance of
methane, of the Cp and ZrÃ/Me resonances mentioned
above and of the OCH2 resonance mentioned above. We
suspect the formation of the alkoxy species
Cp2Zr(Me)(OC18H37), but all attempts to synthesize
this resulted in the formation of a waxy mixture with a
complicated NMR spectrum.
The three-hydrogen methyl resonances are reasonably
attributed to the NMe2 group coordinated to the
borane, and are presumably rendered non-equivalent
because of restricted rotation about the NÃ
/
aryl bond.
The resulting asymmetry results in non-equivalence of
the free NMe2 methyl groups, resulting in their six-
hydrogen resonance being broad. The ring hydrogen
resonances have been assigned using a COSY experi-
ment, and the resulting assignments are also shown.
2.4. Reactions of Cp2ZrMe2 with 1:1:1 n-octadecanol,
B(C6F5)3 and proton sponge
A reaction of Cp2ZrMe2 with an equimolar amount
of [C10H6(NMe2)2H][(n-C18H37O)B(C6F5)3] in CD2Cl2

48
M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ51
/
1
at ꢃ
After 10 min, in addition to resonances of the starting
materials (ꢀ70% of the original intensities), the spec-
trum exhibited a methane resonance at d 0.186, two new
Cp resonances at d 5.94 and 5.99, two new ZrÃMe
resonances at d ꢃ0.07 and ꢃ0.11 and an OCH2
resonance at d 3.82. Some of these are probably to be
attributed to the above mentioned
/
20 8C was monitored by H NMR spectroscopy.
OCH2); 1.39ꢁ
CD2Cl2): 148.2 (dm, JFC
(dm, JFC 253.4 Hz, para CF); 137.6 (dm, JFC
Hz, meta CF) 116.2 (ipso C); 70.5 (OCH2); 32.3, 30.7,
30.1, 30.0, 29.9, 29.8, 29.4, 25.4, 23.1 (CH2); 14.3 (CH3).
/
0.78 (m, 35H, CH2). 13C{1H} (298 K,
239.4 Hz, ortho CF); 140.9
249.0
ꢀ
/
/
ꢀ
/
ꢀ
/
/
/
/
(298 K, toluene-d8) 147.8 (dm, JFC
CF); 140.4 (dm, JFC 256.5 Hz, para CF); 137.2 (dm,
JFC 252.8 Hz, meta CF) 115.2 (ipso C); 67.9 (OCH2);
31.9, 29.8, 29.7, 29.6, 29.5, 29.4, 29.3, 29.0, 24.7, 22.7
(CH2); 13.8 (CH3). 19F NMR: (298 K, CD2Cl2) ꢃ
134.9
(d, Jꢀ21.7 Hz, 2F, ortho); ꢃ164.9 (t, Jꢀ20.9 Hz, 1F,
para); ꢃ
135.5 (d, Jꢀ
Hz, 1F, para); ꢃ
ꢀ/244.6 Hz, ortho
ꢀ
/
ꢀ
/
Cp2Zr(Me)(OC18H37), but again warming the reaction
mixture resulted in considerable decomposition. A
similar reaction but in the presence of a second
/
/
/
/
1
equivalent of B(C6F5)3 resulted in a complex H NMR
/
168.3 (m, 2F, meta). (298 K, toluene-d8) ꢃ
/
spectrum which exhibited the resonances of protonated
proton sponge and of the borate anion [MeB(C6F5)3]ꢃ
(d 0.42), but no methane resonance. Interestingly, only a
single set of 19F resonances were observed, attributable
to [MeB(C6F5)3]ꢃ, and it appears that in this case the
major species formed are alkoxy zirconium compounds
and [C10H6(NMe2)2H]-[MeB(C6F5)3]. Certainly the an-
ticipated catalytic cation [Cp2ZrMe]ꢂ is not a major
species in solution [5b,5c,5d,5e].
/
21.5 Hz, 2F, ortho); ꢃ
/
155.1 (t, Jꢀ
/20.3
/
163.0 (m, 2F, meta). 11B NMR: (298 K,
CD2Cl2) 3.8. (298 K, toluene-d8) 3.2.
3.2. Formation of (n-C18H37SH)B(C6F5)3 (5)
To B(C6F5)3 (8.9 mg, 15.5 mmol) and 4 (5.0 mg, 15.5
mmol) in a 5 mm NMR tube was added 1 ml of
deuterated solvent at r.t. 1H NMR (298 K, CD2Cl2)
3.35 (t, Jꢀ
SCH2); 1.67 (‘q’, Jꢀ
CH2); 1.26 (m, 28H, CH2); 0.88 (t, Jꢀ
(298 K, toluene-d8) 2.57 (t, Jꢀ7.8 Hz, 1H, SH); 2.00
(‘q’, Jꢀ7.4 Hz, 2H, SCH2); 1.34 (m, 24H, CH2); 1.16
(m, 2H, CH2); 1.12 (m, 2H, CH2); 1.04 (m, 2H, CH2);
0.96 (m, 2H, CH2); 0.92 (t, Jꢀ7.1 Hz, 3H, CH3).
13C{1H} (298 K, CD2Cl2): 148.5 (dm, JFC
243.9 Hz,
ortho CF); 142.1 (dm, JFC 243.5 Hz, para CF); 137.7
(dm, JFC
261.5 Hz, meta CF) 114.3 (ipso C); 32.3 (r-
/
8.0 Hz, 1H, SH); 2.54 (‘q’, Jꢀ
7.04 Hz, 2H, CH2); 1.35 (m, 2H,
7.0 Hz, 3H, CH3).
/
7.6 Hz, 2H,
3. Experimental
/
/
All operations were performed under purified argon
using normal Schlenk techniques or an MBraun Lab-
master glove box. Solvents were purified by standard
methods, and distilled and degassed before use. All 1D
1H, 11B, 13C{1H} and 19F NMR spectra and 2D COSY,
HMQC and HSQC spectra, (used for assignment), were
recorded using Bruker AC-200 or Avance 300, 400 or
500 spectrometers, chemical shifts being determined by
/
/
/
ꢀ
/
ꢀ
/
ꢀ
/
CH2); 31.6 (b-CH2); 30.1, 30.0, 29.9, 29.8, 29.7 (CH2);
reference to residual H and 13C solvent peaks for H
1
1
29.4 (a-CH2); 29.2 (CH2); 28.7 (g-CH2); 23.1 (u-CH2);
and 13C{1H} studies, external CFCl3 for 19F studies and
14.3 (CH3). (298 K, toluene-d8) 148.5 (dm, JFC
Hz, ortho CF); 142.2 (dm, JFC 257.1 Hz, para CF);
137.8 (dm, JFC 257.3 Hz, meta CF) 114.4 (ipso C);
ꢀ/261.0
BF3×
/
Et2O for 11B. The compounds Cp2ZrMe2 [9] and
ꢀ
/
B(C6F5)3 [8d] were prepared according to published
procedures. 1,8-(Dimethylamino) naphthalene was pur-
chased from Aldrich and sublimed before use. Toluene-
ꢀ
/
32.4, 31.1, 30.3, 30.2, 30.1, 29.9, 29.8, 29.3 (CH2); 29.0
(SCH2); 28.4, 23.2 (CH2); 14.4 (CH3). 19F NMR: (298
d8 and CD2Cl2 were dried over sodiumꢁbenzophenone
/
K, CD2Cl2) ꢃ
/
131.9 (d, Jꢀ
/
16.6 Hz, 2F, ortho); ꢃ
/
153.1
and CaH2, respectively, and vacuum transferred prior to
use. The ‘’ in the text indicates a resonance of a
deceptively simple nature.
n-Octadecanol (1) and n-octadecanethiol (4) were
purchased from Aldrich and recrystallized before use.
Full NMR data are given in the supplementary material.
(s, 1F, para); ꢃ
/
163.6 (m, 2F, meta). (298 K, toluene-d8)
ꢃ
/
131.9 (s, 2F, ortho); ꢃ
/
152.1 (s, Hz, 1F, para); ꢃ
/
162.7
(m, 2F, meta). 11B NMR: (298 K, CD2Cl2) 12.9. (298 K,
toluene-d8) 9.6.
3.1. Formation of (n-C18H37OH)B(C6F5)3 (2)
3.3. Determination of the stoichiometry of the reaction of
n-octadecanol and B(C6F5)3
To B(C6F5)3 (10 mg, 18.5 mmol) and 1 (5 mg, 18.5
mmol) in a 5 mm NMR tube was added 1 ml of
deuterated solvent at room temperature (r.t.). 1H
NMR (298 K, CD2Cl2) 6.19 (br s, 1H, OH) 4.02 (t,
A series of solutions was prepared by dissolving n-
octadecanol (5 mg, 20 mmol) and varying amounts of
B(C6F5)3 (0.6:1ꢁ5:1) in 1 ml CD2Cl2 in several 5 mm
/
Jꢀ
30H, CH2); 0.86 (t, Jꢀ
toluene-d8) 5.93 (br s, 1H, OH) 3.35 (t, Jꢀ
/
6.9 Hz, 2H, OCH2); 1.79 (m, 2H, -CH2); 1.26 (m,
6.7 Hz, 3H, CH3). (298 K,
6.2 Hz, 2H,
NMR tubes. The solutions were allowed to react for 1 h
1
before measurement of the H NMR spectra; see Table
/
/
S1, supplementary material, for data.

M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ
/51
49
3.4. Measurement of equilibrium constant of the reaction
of n-octadecanol and B(C6F5)3
1H NMR (298 K, CD2Cl2): 19.39 (m, 1H, NH); 8.04 (d,
Jꢀ8.3 Hz 2H, CH); 7.76 (d, Jꢀ7.8 Hz, 2H, CH); 7.71
(‘t’, Jꢀ7.9, 2H, CH); 3.14 (d, Jꢀ2.6 Hz, 12H, NCH3);
3.07 (t, Jꢀ6.6 Hz, 2H, OCH2); 1.41 (m, 2H, b-CH2);
1.26 (m, 30H, CH2); 0.88 (t, Jꢀ6.5 Hz, 3H, CH3). (298
K, toluene-d8): 18.32 (br s, 1H, NH); 7.44 (d, Jꢀ8.0 Hz
2H, CH); 7.17 (‘t’, Jꢀ7.6 Hz, 2H, CH); 6.88 (d, Jꢀ6.9,
2H, CH); 3.62 (t, Jꢀ7.1 Hz, 2H, OCH2); 2.23 (d, Jꢀ
1.8 Hz, 12H, NCH3); 1.76 (m, 2H, -CH2); 1.44 (m, 2H,
?-CH2); 1.31 (m, 28H, CH2); 0.92 (t, Jꢀ6.7 Hz, 3H,
CH3). 13C{1H} NMR(298 K, CD2Cl2): 148.3 (dm,
/
/
/
/
The equilibrium constant for the adduct formation
was measured using 1H NMR methods. Samples for
observing the complexed proton shift were prepared
/
/
/
from a stock solution of B(C6F5)3 (40 mg, 8ꢄ
/
10ꢃ5 mol)
/
/
and n-octadecanol (21 mg, 8ꢄ
/
10ꢃ5 mol), dissolved in
/
/
CD2Cl2 (1 ml, 1.362 g). The vessel was sealed and left to
react for 1 h. Portions of this solution were then placed
in 5 mm NMR tubes and the volumes were adjusted to
1000 ml with the appropriate amount of CD2Cl2 (see
Table S2, supplementary material, for data).
/
JFC
JFC
ꢀ
/
242.7 Hz, ortho CF); 143.3 (ipso C); 138.4 (dm,
ꢀ
/
241.1 Hz, para CF); 136.7 (dm, JFC 254.1 Hz,
ꢀ
/
meta CF); 135.7 (ipso C); 130.5 (CH); 127.7 (CH);
121.5 (CH); 118.8 (ipso C); 109.8 (ipso C); 65.1 (OCH2);
46.8 (NCH3); 33.2, 32.3, 30.1, 26.7, 23.1 (CH2); 14.2
3.5. Reaction with 2:1 stoichiometry
To B(C6F5)3 (20 mg, 39 mmol) and n-C18H37OH (5
mg, 18.5 mmol) in a 5 mm NMR tube was added 1 ml of
deuterated solvent at r.t. 1H NMR (298 K, CD2Cl2) 6.24
(CH3). (298 K, toluene-d8): 148.9 (dm, JFC
ortho CF); 143.1 (ipso C); 139.7 (low field part of
doublet, para CF); 137.1 (dm, JFC 248.8 Hz, meta
ꢀ
/
245.6 Hz,
ꢀ
/
(t, Jꢀ
OCH2); 1.80 (m, 2H, -CH2); 1.26 (m, 30H, CH2); 0.87 (t,
Jꢀ6.8 Hz, 3H, CH3). (298 K, toluene-d8) 5.94 (t, Jꢀ
4.4 Hz, 1H, OH); 3.37 (dt, Jꢀ4.4, 6.6 Hz, 2H, a-CH2);
1.39ꢁ0.78 (m, 35H, CH2).
/
4.4 Hz, 1H, OH); 4.03 (dt, Jꢀ
/
4.4, 6.9 Hz, 2H,
CF); 135.6 (ipso C); 129.9 (CH); 127.1 (CH); 120.8
(CH); 118.4 (ipso C); 65.3 (OCH2); 45.2 (NCH3); 33.8,
32.4, 30.6, 30.5, 30.3, 30.2, 29.9, 27.0, 23.2 (CH2); 14.4
/
/
/
(CH3). 19F NMR (298 K, CD2Cl2): ꢃ
Hz, 2F, ortho); ꢃ165.0 (t, Jꢀ
168.4 (m, 2F, meta). (298 K, toluene-d8): ꢃ
Jꢀ24.4 Hz, 2F, ortho); ꢃ164.0 (m, 1F, para); ꢃ
(m, 2F, meta). 11B NMR: (298 K, CD2Cl2) ꢃ
2.4. (298
/
133.9 (d, Jꢀ
19.9 Hz, 1F, para); ꢃ
135.6 (d,
167.4
/
23.0
/
/
/
/
/
3.6. Determination of the stoichiometry and equilibrium
constant of the reaction of n-octadecanethiol and
B(C6F5)3
/
/
/
/
K, toluene-d8) ꢃ3.1. MS(FAB, nitrobenzyl alcohol):
/
FABꢂ m/e 215.1 [C10H6(NCH3)2H]ꢂ; FABꢃ m/e
781.1 [(n-C18H37O)B(C6F5)3]ꢃ.
A series of solution was prepared by dissolving n-
octadecanethiol (5.0 mg, 17.5 mmol) and varying
amounts of B(C6F5)3 (1:5ꢁ/5:1) in 1 ml of deuterated
3.8. Synthesis of [C10H6(NMe2)2H][(n-
C18H37S)B(C6F5)3] (6)
solvent in several 5 mm NMR tubes. The solutions were
1
allowed to react for 1 h before measurement of the H
NMR spectra; see Table S3 and S4, supplementary
material, for data in CD2Cl2 and toluene-d8.
B(C6F5)3 (0.5360 g, 1.05 mmol) and 4 (0.3000 g, 1.05
mmol) were dissolved in dichloromethane (30 ml) at ꢃ
/
78 8C. They were allowed to slowly warm to r.t., where
they were allowed to stir for a further 1 h. To this
3.7. Synthesis of [C10H6(NMe2)2H][(n-
C18H37O)B(C6F5)3] (3)
solution, cooled to ꢃ78 8C, was added proton sponge
/
(0.2244 g, 1.05 mmol) drop-wise in dichloromethane (15
ml). The solution was allowed to warm slowly to r.t. and
was stirred for a further 3 h. The solution was
concentrated, in vacuo to 5 ml, cooled to 0 8C and
hexanes, (30 ml), added to give a white precipitate. The
supernatant was decanted and the solid was washed with
B(C6F5)3 (175 mg, 340 mmol) and 1 (92 mg, 340 mmol)
were dissolved in dichloromethane (30 ml) at ꢃ78 8C.
/
They were allowed to slowly warm to r.t., where they
were allowed to stir for a further 1 h. To this solution,
cooled to ꢃ78 8C, was added proton sponge (74 mg,
/
340 mmol) drop-wise in dichloromethane (15 ml). The
solution was allowed to warm slowly to r.t. and was
stirred for a further 3 h. The solvent was removed in
vacuo to leave a colorless, viscous oil. Hexanes (10 ml)
were added to the flask, and the mixture was sonicated
for 1 h, during which time the oil turned into a white
precipitate. The supernatant was decanted and the solid
hexanes (2ꢄ10 ml). The solvent was removed in vacuo,
/
and a waxy pale yellow solid was isolated 0.5062 g (0.50
mmol, 48%). Anal. Calc. for C50H56B1F15N2S1: C, 59.3;
1
H, 5.6; N, 2.8. Found: C, 57.8; H, 5.1; N, 2.8%. H
NMR (298 K, CD2Cl2): 19.34 (m, 1H, NH); 8.04 (d,
Jꢀ
(d, Jꢀ
1.93 (t, Jꢀ
(t, Jꢀ6.8 Hz, 3H, CH3). (298 K, toluene-d8): 18.36 (m,
1H, NH); 7.34 (d, Jꢀ
Hz, 2H, CH); 6.88 (d, Jꢀ
/
8.6 Hz 2H, CH); 7.78 (d, Jꢀ
8.0, 2H, CH); 3.15 (d, Jꢀ
7.8 Hz, 2H, SCH2); 1.27 (m, 32H, CH2); 0.88
/
8.6 Hz, 2H, CH); 7.71
/
/
2.8 Hz, 12H, NCH3);
was washed with hexanes (2ꢄ
/
10 ml). The solvent was
/
removed in vacuo, and the white solid was isolated 284
mg (285 mmol, 84%). Anal. Calc. for C50H56B1F15N2O1:
C, 60.3; H, 5.7; N, 2.8. Found: C, 57.7; H, 5.2; N, 2.9%.
/
/
8.0 Hz 2H, CH); 7.15 (‘t’, Jꢀ
/8.3
/
7.6, 2H, CH); 2.41 (t, Jꢀ
/7.5

50
M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ51
/
Hz, 2H, SCH2); 2.31 (d, Jꢀ
(m, 2H, -CH2); 1.31 (m, 30H, CH2); 0.92 (t, Jꢀ
3H, CH3). 13C{1H} NMR(298 K, CD2Cl2): 148.5 (dm,
/
2.5 Hz, 12H, NCH3); 1.52
3.10. Reactions of Cp2ZrMe2 with 1:1:1 n-octadecanol,
B(C6F5)3 and proton sponge
/
6.8 Hz,
JFC
JFC
ꢀ
/
235.2 Hz, ortho CF); 143.5 (ipso C); 138.5 (dm,
Solid Cp2ZrMe2 (4.91 mg, 0.02 mmol) was dissolved
ꢀ
/
247.0 Hz, para CF); 136.9 (dm, JFC 250.7 Hz,
ꢀ
/
in
a
C18H37O)B(C6F5)3] (0.02 mmol) in 0.5 ml CD2Cl2 at
solution
of
[C10H6(NMe2)2H][(n-
meta CF); 136.0 (ipso C); 130.4 (CH); 127.7 (CH);
121.5 (CH); 118.8 (ipso C); 113.0(ipso C); 46.8 (NCH3);
32.9 (b-CH2); 32.3, 30.1, 29.9, 29.8 (CH2); 29.7 (SCH2);
14.2 (CH3). (298 K, toluene-d8): 149.0 (dm, JFC
Hz, ortho CF); 143.3 (ipso C); 139.9 (low field part of
doublet, para CF); 137.2 (dm, JFC 246.5 Hz, meta
CF); 135.6 (ipso C); 129.7 (CH); 127.1 (CH); 120.9
(CH); 118.5 (ipso C); 45.2 (NCH3); 33.5 (b-CH2); 32.4,
(CH2); 30.3 (SCH2); 30.3, 30.2, 29.9, 23.2 (CH2); 14.4
1
ꢃ
/
20 8C, and the reaction was monitored by H NMR
spectroscopy. After 20 min, in addition to resonances of
the starting materials (ꢀ70% of the original intensities),
there were observed a methane resonance at d 0.186,
two new Cp resonances at d 5.99 and 5.94, two new ZrÃ
Me resonances at d ꢃ0.07 and ꢃ0.11 and a OCH2R
ꢀ
/
242.5
/
ꢀ
/
/
/
/
resonance at d 3.82 (t, JHH 5.9 Hz). Some of these are
probably to be attributed to the above mentioned
compound Cp2Zr (Me)(OCH2R), but again warming
the reaction mixture resulted in considerable decom-
position.
(CH3). 19F NMR (298 K, CD2Cl2): ꢃ
Hz, 2F, ortho); ꢃ164.6 (t, Jꢀ
168.4 (m, 2F, meta). (298 K, toluene-d8): ꢃ
Jꢀ20.5 Hz, 2F, ortho); ꢃ163.3 (t, Jꢀ21.9 Hz, 1F,
para); ꢃ
167.4 (m, 2F, meta). 11B NMR: (298 K,
CD2Cl2) ꢃ
/
132.9 (d, Jꢀ
20.4 Hz, 1F, para);
131.8 (d,
/
20.4
/
/
ꢃ
/
/
/
/
/
The same reaction in the presence of a second
1
equivalent of B(C6F5)3 resulted in a complex H NMR
/
/
11.2. (298 K, toluene-d8) ꢃ
/
10.4. MS(FAB,
spectrum which exhibited the resonances of protonated
proton sponge and of the borate anion [MeB(C6F5)3]ꢃ
(d 0.42), but only a very weak methane resonance. Since
only a single set of 19F resonances were observed, those
glycerol): FABꢂ m/e 215.1 [C10H6(NCH3)2H]ꢂ; FABꢃ
m/e 797.2 [(n-C18H37S)B(C6F5)3]ꢃ.
of [MeB(C6F5)3]ꢃ at d ꢃ
166.10 (t, JFF 20.69 Hz) and ꢃ
Hz), it appears that the major species formed are alkoxy
/
134.2 (d, JFF 18.8 Hz),
168.7 (dt, JFF 18.8
3.9. Reactions between Cp2ZrMe2 and n-octadecanol
ꢃ
/
/
To a solution of 15 mg (0.06 mmol) of Cp2ZrMe2 (dCp
zirconium
[MeB(C6F5)3].
compounds
and
[C10H6(NMe2)2H]-
6.07, dMe
added a solution of 15.8 mg (0.058 mmol) of 1 in a small
ꢃ
/
0.51) in 0.5 ml CD2Cl2 at ꢃ
/
50 8C was
1
amount of CD2Cl2. A H NMR spectrum run immedi-
ately showed, in addition to the resonances of 1 (d 3.58,
3.11. Supporting information available
1.53, 1.26, 0.88) and Cp2ZrMe2 (d 6.07, ꢃ
/
0.51), at
A listing of all data used in the calculation of the
equilibrium constants.
ꢀ
/
70% of the original intensities, the resonance of
methane at d 0.18, two new Cp resonances at d 5.98
and 5.92 (2:1 ratio) and two new methyl resonances at d
ꢃ
/
0.094 and ꢃ0.17 (1:2 ratio). There was also an OCH2
/
Acknowledgements
product resonance at d 3.76 (t, JHH 6.1 Hz). On
warming to 20 8C, the NMR spectrum exhibited new
Financial support from Bayer Inc. and the Natural
Sciences and Engineering Research Council made this
research possible. We also thank Dr. M.J. Hynes for
making the program EQNMR available to us.
resonances (dCp 6.009, 5.96; dMe
ꢃ
/
0.019, ꢃ0.064),
/
indicating that the reaction had proceeded further, but
the resonances of Cp2ZrMe2 and n-octadecanol were
still present. On prolonged standing at 20 8C, the
spectrum became very complicated.
Reaction of Cp2ZrMe2 (19 mg, 0.07 mmol) with 0.5
References
equiv. of 1 at ꢃ50 8C resulted in little reaction after 10
/
min, but reaction of Cp2ZrMe2 (8.83 mg, 0.035 mmol)
with 2 equiv. of n-octadecanol (19 mg, 0.07 mmol) at
[1] For useful reviews see: (a) P.C. Mohring, N.J. Coville, J.
¨
Organomet. Chem. 479 (1994) 1.
(b) V.K. Gupta, S. Satish, I.S. Bhardwaj, J. Macromol. Sci., Rev.
Macromol. Chem. Phys. C34 (1994) 439.
(c) H.H. Brintzinger, D. Fischer, R. Mulhaupt, B. Rieger, R.M.
¨
20 8C (mixed at ꢃ20 8C) resulted in immediate dis-
/
appearance of the resonances of the Cp2ZrMe2 and the
appearance of the resonance of methane at d 0.21, of
Waymouth, Angew. Chem., Int. Ed. 34 (1995) 1143.
(d) M. Bochmann, J. Chem. Soc., Dalton Trans. (1996) 255.
(e) W. Kaminsky, M. Arndt, M. Adv. Polymer Sci. 127 (1997) 143.
(f) J.C.W. Chien, Topics in Catalysis 7 (1999) 125.
new Cp and methyl resonances at d 6.01 and ꢃ0.059,
/
respectively, and of a new OCH2 resonance at d 3.816 (t,
JHH 6.1 Hz). The product is almost certainly an alkoxy
species such as Cp2ZrMe (OC18H37), but all attempts to
synthesize it on a larger scale resulted in the formation
of a waxy mixture with a complicated NMR spectrum.
(g) H.G. Alt, A. Koppl, Chem. Rev. 100 (2000) 1205.
¨
(h) G.W. Coates, Chem. Rev. 100 (2000) 1223.
(i) L. Resconi, L. Cavallo, A. Fait, F. Piemontesi, Chem. Rev. 100
(2000) 1253.

M.J. Drewitt et al. / Inorganica Chimica Acta 335 (2002) 43ꢁ
/51
51
(j) K. Angermund, G. Fink, V.R. Jensen, R. Kleinschmidt, Chem.
Rev. 100 (2000) 1457.
Polymerization: Fundamentals and Applications 665 ACS Sym-
posium Series, American Chemical Society, New York, 1997, p.
96;
(k) J. Scheirs W. Kaminsky, (Eds.), ‘Metallocene-based Poly-
olefins’, Wiley, New York, 1999.
(g) G.S. Hill, L. Manojlovic-Muir, K.W. Muir, R.J. Puddephatt,
Organometallics 16 (1997) 525;
[2] (a) L. Jia, X. Yang, C.L. Stern, T.J. Marks, Organometallics 16
(1997) 842;
(h) A.A. Danopoulos, J.R. Galsworthy, M.L.H. Green, S.
Cafferkey, L.H. Doerrer, M.B. Hursthouse, J. Chem. Soc.,
Chem. Commun. (1998) 2529;
(b) P.A. Deck, C.L. Beswick, T.J. Marks, J. Am. Chem. Soc. 120
(1998) 1772;
(c) C.L. Beswick, T.J. Marks, Organometallics 18 (1999) 2410;
(d) L. Luo, T.J. Marks, Topics in Catalysts 7 (1999) 7;
(e) E.Y.-X. Chen, Chem. Rev. 100 (2000) 1391;
(f) J. Zhou, S.J. Lancaster, D.A. Walker, S. Beck, M. Thornton-
Pett, M. Bochmann, J. Am. Chem. Soc. 123 (2000) 223.
[3] S.H. Strauss, Chem. Rev. 93 (1993) 927.
[4] (a) L. Jia, X. Yang, C.L. Stern, T.J. Marks, Organometallics 13
(1994) 3755;
(i) L.H. Doerrer, M.L.H. Green, J. Chem. Soc., Dalton Trans.
(1999) 4325;
(j) J.L. Priego, L.H. Doerrer, L.H. Rees, M.L.H. Green, J. Chem.
Soc., Chem. Commun. (2000) 779;
(k) C. Bergquist, B.M. Bridgewater, C.J. Harlan, J.R. Norton,
R.A. Friesner, G. Parkin, J. Am. Chem. Soc. 122 (2000) 10581;
(l) H.A. Kalamarides, S. Iyer, J. Lipian, L.F. Rhodes, Organo-
metallics 19 (2000) 3983.
(b) L. Jia, X. Yang, A. Ishihara, T.J. Marks, Organometallics 14
(1995) 3135;
[6] (a) S.J. Lancaster, D.A. Walker, M. Thornton-Pett, M. Boch-
mann, J. Chem. Soc., Chem. Commun. (1999) 1533;
(b) R.E. LaPointe, PCT Int. Application WO 9942467, 1999 (Dow
Chemical Co.).
(c) L. Li, T.J. Marks, Organometallics 17 (1998) 3996;
(d) Y.-X. Chen, M.V. Metz, L. Li, C.L. Stern, T.J. Marks, J. Am.
Chem. Soc. 120 (1998) 6287;
[7] R.E. LaPointe, G.R. Roof, K.A. Abboud, J. Klosin, J. Am.
Chem. Soc. 122 (2000) 9560.
[8] (a) H. Jacobsen, H. Berke, S. Doring, G. Kehr, G. Erker, R.
(e) L. Li, C.L. Stern, T.J. Marks, Organometallics 19 (2000) 3332;
(f) M.V. Metz, D.J. Schwartz, C.L. Stern, P.N. Nickias, T.J.
Marks, Angew. Chem., Int. Ed. 39 (2000) 1312;
¨
Frohlich, O. Meyer, Organometallics 18 (1999) 1724;
¨
(g) K. Kohler, W.E. Piers, A.P. Jarvis, S. Xin, Y. Feng, A.M.
¨
Bravakis, S. Collins, W. Clegg, G.P.A. Yap, T.B. Marder,
Organometallics 17 (1998) 3557;
(b) D.J. Parks, W.E. Piers, M. Parvez, R. Atencio, M.J.
Zawarotko, Organometallics 17 (1998) 1369;
(c) D.C. Bradley, I.S. Harding, A.D. Keefe, M. Motevalli, D.H.
Zheng, J. Chem. Soc., Dalton Trans. (1996) 3931;
(d) J.L. Pohlmann, F.E. Brinckmann, Z. Naturforsch. 20b (1965)
5;
(h) V.C. Williams, W.E. Piers, W. Clegg, M.R.J. Elsegood, S.
Collins, T.B. Marder, J. Am. Chem. Soc. 121 (1999) 3244;
(i) V.C. Williams, G.J. Irvine, W.E. Piers, Z. Li, S. Collins, W.
Clegg, M.R.J. Elsegood, T.B. Marder, Organometallics 19 (2000)
1619;
(e) D. Vagedes, R. Frohlich, G. Erker, Angew. Chem., Int. Ed. 38
¨
(1999) 3362.
(j) W.E. Piers, G.J. Irvine, V.C. Williams, Eur. J. Inorg. Chem.
(2000) 2131;
[9] A.R. Siedle, R.A. Newmark, W.M. Lamanna, J.N. Schroepfer,
Polyhedron 9 (1990) 301.
(k) W.E. Piers, Y. Sun, L.W.M. Lee, Topics in Catalysis 7 (1999)
133.
[10] P.C. Wailes, H. Weigold, A.P. Bell, J. Organomet. Chem. 34
(1972) 155.
[5] (a) A.R. Siedle, R.A. Newmark, W.M. Lamanna, J.C. Huffman,
Organometallics 12 (1993) 1491;
[11] (a) R.G. Kidd, in: P. Laszlo (Ed.), NMR of Newly Accessible
Nuclei, vol. 2, Academic Press, New York, 1983;
(b) S. Berger, S. Braun, H.O. Kalinowski, NMR Spectroscopy of
Non-Metals G, vol. 4, Thieme, New York, 1994.
[12] (a) L. Fielding, Tetrahedron 56 (2000) 6151;
(b) C.D. Chriswell, A.A. Schilt, Anal. Chem. 47 (1975) 1623.
[13] D.R. Alston, T.H. Lilley, J.F. Stoddart, Chem. Commun. (1985)
1600.
(b) A.R. Siedle, W.M. Lamanna, R.A. Newmark, J. Stevens, D.E.
Richardson, M. Ryan, Makromol. Chem. Macromol. Symp. 66
(1993) 215;
(c) A.R. Siedle, W.M. Lamanna, US Patent 5296433, 1994
(Minnesota Mining and Manufacturing Co);
(d) A.R. Siedle, W.M. Lamanna, US Patent 5416177, 1995
(Minnesota Mining and Manufacturing Co);
(e) T.D. Shaffer, J.R. Ashbaugh, J. Polym. Sci., Part A 35 (1997)
329;
[14] M.J. Hynes, J. Chem. Soc., Dalton Trans. (1993) 311.
[15] Addition of 1 equiv. of Proton Sponge to 1 equiv. of n-
octadecanol or n-octadecanethiol in CD2Cl2 or toluene-d2 gave
1
(f) T.D. Shaffer, in: R. Faust, T.D. Shaffer (Eds.), Cationic
no observable changes in the resonances in the H NMR spectra.