Organoaluminum hydroxides supported by β-diketiminato ligands: Synthesis, structural characterization, and reactions

Article abstract of DOI:10.1021/om700969g

Three β-diketiminato ligands (L¹ = HC[C(Me)N(Ar)] ₂, Ar = 2,4,6-Me₃C₆H₂; L² = HC[C(Me)N(Ar)]₂, Ar = 2,6-iPr₂C₆H ₃; L³ = HC[C(tBu)N(Ar)]₂, Ar = 2,6iPr ₂C₆H₃) were employed to prepare the organoaluminum hydroxides LAlR(OH) (R = Me, Et, Ph, OEt, OSiMe₃) by hydrolysis of the corresponding chlorides in the presence of a N-heterocyclic carbene as HCl scavenger. Reaction of the organoaluminum hydroxide with Cp ₂ZrMe₂ in toluene afforded the heterobimetallic oxide LAlR(μ-O)ZrMeCp₂ under evolution of methane. All compounds were characterized by multinuclear NMR, IR, mass spectrometry, and elemental analysis. The structures of L¹AlPh(OH) (10), L²AlPh(OH) (11), L²AlOEt(OH) (12), L²AlOSiMe₃(OH) (13), and L²AlPh(μ-O)ZrMeCp₂ (17) were determined by single-crystal X-ray diffraction studies. The polymerization of ethylene was studied with compound 17, which exhibits moderate catalytic activity.

Full text of DOI:10.1021/om700969g

Organometallics 2008, 27, 769–777
769
Organoaluminum Hydroxides Supported by ꢀ-Diketiminato
Ligands: Synthesis, Structural Characterization, and Reactions
Ying Yang,†,‡ Thomas Schulz,‡ Michael John,‡ Zhi Yang,‡ Victor Manuel Jiménez-Pérez,‡
Herbert W. Roesky,*,‡ Prabhuodeyara M. Gurubasavaraj,‡ Dietmar Stalke,‡ and Hongqi Ye†
School of Chemistry and Chemical Engineering, Central South UniVersity,
Changsha, 410083, P.R. China and Institut für Anorganische Chemie der UniVersität Göttingen,
Tammannstraße 4, 37077 Göttingen, Germany
ReceiVed September 29, 2007
Three ꢀ-diketiminato ligands (L1 ) HC[C(Me)N(Ar)]2, Ar ) 2,4,6-Me3C6H2; L2 ) HC[C(Me)N(Ar)]2,
Ar ) 2,6-iPr2C6H3; L3 ) HC[C(tBu)N(Ar)]2, Ar ) 2,6-iPr2C6H3) were employed to prepare the
organoaluminum hydroxides LAlR(OH) (R ) Me, Et, Ph, OEt, OSiMe3) by hydrolysis of the corresponding
chlorides in the presence of a N-heterocyclic carbene as HCl scavenger. Reaction of the organoaluminum
hydroxide with Cp2ZrMe2 in toluene afforded the heterobimetallic oxide LAlR(µ-O)ZrMeCp2 under
evolution of methane. All compounds were characterized by multinuclear NMR, IR, mass spectrometry,
and elemental analysis. The structures of L1AlPh(OH) (10), L2AlPh(OH) (11), L2AlOEt(OH) (12),
L2AlOSiMe3(OH) (13), and L2AlPh(µ-O)ZrMeCp2 (17) were determined by single-crystal X-ray diffraction
studies. The polymerization of ethylene was studied with compound 17, which exhibits moderate catalytic
activity.
previously introduced, including L2Al(OH)2,6 [L2Al(OH)]2(µ-
O),7 L2Al(OH)OAlL(OCHdNtBu),8 L2AlMe(OH),3 [L2AlCl(µ-
OH)]2,9 and L2Al(OH)[C(SiMe3)CH(SiMe3)].10 Among these
aluminum hydroxides, however, due to uncontrolled reactivity
or limited availability, only L2AlMe(OH) so far succeeded
in gaining practical application in the preparation of oxo-
bridged heterometallic oxides as catalysts.3 Very recently an
ethyl-substituted aluminum hydroxide L2AlEt(OH) and its
derivative L2AlEt(µ-O)ZrMeCp2 have been prepared and
characterized in our laboratory.11 Further efforts are being
made to use a ligand effect to improve the activity and
thermal stability of catalysts containing the M-O-M′
moiety.12 Herein we report the preparation of a new orga-
noaluminum hydroxide LAlR(OH) supported by three dif-
ferent ꢀ-diketiminato ligands (L ) L1, L2, L3; Scheme 1)
together with a variety of substituents on aluminum (R )
Me, Et, Ph, OEt, OSiMe3). Subsequently, the reactivity of
the new organoaluminum hydroxides is investigated using
the reaction with Cp2ZrMe2 to afford the corresponding
heterobimetallic oxide LAlR(µ-O)ZrMeCp2.
Introduction
MAO-activated metallocene complexes of group 4 metals
play an important role as catalysts in olefin polymerization.1
Attempts to develop MAO-free catalyst systems began with
cationic complexes stabilized by weakly coordinating anions.2
A well-defined heterobimetallic oxide L2AlMe(µ-O)ZrMeCp2
(L2 ) HC[C(Me)N(Ar)]2, Ar ) 2,6-iPr2C6H3) emerged as a
single-site homogeneous catalyst with noticeable activity.3
Recent ab initio calculations demonstrate that the oxygen
within the M-O-M′ unit is responsible for the necessary
depletion of electron density at the metal sites.4 These results
have initiated the development of oxo-bridged heterobime-
tallic systems derived from organometallic hydroxides to
explore potentially good catalysts.5 Several organoaluminum
hydroxides supported by a ꢀ-diketiminato ligand have been
* To whom correspondence should be addressed. Email: hroesky@
gwdg.de.
† Central South University.
‡ Universität Göttingen.
(6) Bai, G.; Peng, Y.; Roesky, H. W.; Li, J.; Schmidt, H.-G.; Noltemeyer,
M. Angew. Chem., Int. Ed. 2003, 42, 1132–1135.
(1) (a) Britovsek, G. J. P.; Gibson, V. C.; Wass, D. F. Angew. Chem.,
Int. Ed. 1999, 38, 428–447. (b) Alt, H. G.; Koppl, A. Chem. ReV. 2000,
100, 1205–1221. (c) Hlatky, G. G. Chem. ReV. 2000, 100, 1347–1376.
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J. Am. Chem. Soc. 1991, 113, 8570–8571. (c) Yang, X.; Stern, C. L.; Marks,
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Angew. Chem., Int. Ed. 2003, 42, 5502–5506.
(8) Peng, Y.; Bai, G.; Fan, H.; Vidovic, D.; Roesky, H. W.; Magull, J.
Inorg. Chem. 2004, 43, 1217–1219.
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10.1021/om700969g CCC: $40.75
2008 American Chemical Society
Publication on Web 01/24/2008

770 Organometallics, Vol. 27, No. 4, 2008
Yang et al.
Scheme 1
is prone to be oily in the presence of organic solvents and hard
to crystallize, although crystalline L′AlMe(Cl) (L′ ) HC[C(Me)
N(Ar)]2, Ar ) p-Tol) can be isolated from toluene at -78 °C.13
Synthesis of Aluminum Hydroxides 8–13. Subsequent
hydrolysis of aluminum chlorides 2-7 with 1 equiv of H2O in
the presence of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene
(abbreviated as :C) as HCl scavenger9,14 successfully afforded
organoaluminum hydroxides 8-13, while the attempt to hy-
drolyze L1AlMe(Cl) (1) gave only trace amounts of the target
L1AlMe(OH) accompanied by the free ligand L1H and an
insoluble precipitate.
Scheme 2
1
The H NMR spectra of 8-13 feature a singlet for the OH
proton in the range δ 0.54–0.63 ppm, which is in agreement
with previous observations for L2AlMe(OH) (δ 0.53 ppm)3 and
L2AlEt(OH) (δ 0.64 ppm).11 The IR spectra of aluminum
hydroxides 8 and 11-13 exhibit the OH stretching frequency
in the range 3720–3732 cm-1, consistent with those reported
for L2AlMe(OH) (3728 cm-1)3 and L2AlEt(OH) (3729 cm-1).11
In the mass spectrum of 10, the strongest peak corresponds
to the fragment [2M+ - Ph - Me - 3H], accompanied by a
weak signal for the molecular ion. In the IR spectrum of 10,
the OH stretching frequency (3671 cm-1) deviates substantially
from the other terminal hydroxides and is more comparable to
those of [(tBu)2Al(µ-OH)]3 (3584 cm-1) and [(tBu)2Al(µ-
OH)]3 · 2THF (3690 cm-1).15 These observations strongly
suggest a dimeric composition of 10 in the solid state, in which
two monomer units are associated via µ-OH groups. In solution,
Results and Discussion
Synthesis of Organoaluminum Chlorides 1–7. The syn-
thesis of the monomeric alkyl aluminum chloride LAlR(Cl) (L
) L1, R ) Me, 1; L ) L3, R ) Me, 2; L ) L1, R ) Et, 3) was
readily achieved by the straightforward reaction of RAlCl2 with
the respective LLi in toluene (Scheme 2).
1
the H NMR spectrum of 10 reveals the coexistence of two
sets of resonances that are populated approximately in a 5:1
ratio and slowly equilibrate at room temperature. The minor
species contains an OH resonance (δ 0.62 ppm), which is close
to the other terminal hydroxides and was therefore assigned to
the monomer, whereas the OH resonance of the major species
(δ 1.79 ppm) indicates a bridging OH proton that is substantially
displaced from its original position, presumably due to dimer-
ization. A comparable variability of the µ-OH resonance has
beenobservedin[(tBu)2Al(µ-OH)]3 (δ2.02ppm)and[(tBu)2Al(µ-
OH)]3 · 2THF (δ 3.42 ppm).15
The H NMR spectrum of L1AlMe(Cl) (1) shows a high-
1
field singlet (δ -0.48 ppm) corresponding to the protons of the
Al-bound methyl group, which is shifted slightly downfield
compared to those of L2AlMe(Cl) (δ -0.64 ppm)9 and
L3AlMe(Cl) (2) (δ -0.73 ppm). Similarly, in the H NMR
1
spectrum of L1AlEt(Cl) (3), one quartet (δ 0.08 ppm) and one
triplet (δ 0.89 ppm), assigned to the methylene and methyl
protons of the ethyl group on Al, show downfield shifts relative
to those of L2AlEt(Cl) (δ -0.04, 0.80 ppm).11 The mass spectra
of the alkyl aluminum chlorides 1-3 exhibit the base peak as
fragment [M+ - R].
1
A similar effect is observed in the H NMR spectrum of 9;
however, in this case the relative populations of the monomer
(δ 0.50 ppm) and the dimer (δ 1.27 ppm) are reversed (7:1).
The bridging OH group in 9 is also characterized by the OH
stretch (3672 cm-1) in the IR spectrum. In contrast, the mass
spectrum in the gas phase shows the fragment [M+ - Me] as
the base peak, and no larger fragment related to the dimer is
detected.
When a solution of LAlCl2 (L ) L1, L2) was treated with a
stoichiometric amount of PhLi, however, no effective halide
metathesis was observed, presumably due to the size of the
phenyl group. An alternative route allowed access to the phenyl-
substituted aluminum chloride LAlPh(Cl) (L ) L1, 4; L ) L2,
5) by adding a solution of LLi to a prereacted mixture of AlCl3
and PhLi in toluene; obviously PhAlCl2 has to be formed first
followed by the reaction with LLi. Broad 13C NMR resonances
at 146.1 and 144.0 ppm for 4 and 5, respectively, demonstrate
the formation of an Al-C bond. The presence of three further
13C resonances (for ortho, meta, and para CH groups) indicates
that the phenyl ring rapidly rotates in solution. In the mass
Synthesis of Heterobimetallic Oxides 14–19. Further reac-
tions were performed to study the reactivity of the OH group
in the organoaluminum hydroxides. Treatment of 8–13, respec-
tively, with 1 equiv of Cp2ZrMe2 in toluene at 100 °C led to
the formation of the corresponding LAlR(µ-O)ZrMeCp2 (14–19)
in modest yield, along with the elimination of methane. The IR
spectra of 14–19 are devoid of any absorption in the reasonable
range for OH groups, consistent with the absence of hydroxyl
spectra of 4 and 5, two strong peaks ([M+ - Ph] and [M+
Ph - Me]) are present in both cases.
-
1
proton resonances in the H NMR spectra. The compositions
of 14–19 are further evidenced by mass spectra, elemental
Treatment of L2AlCl2 with LiOEt and LiOSiMe3 smoothly
afforded L2AlOEt(Cl) (6) and L2AlOSiMe3(Cl) (7), respectively.
1
(13) Qian, B.; Ward, D. L.; Smith, M. R., III. Organometallics 1998,
17, 3070–3076.
In the H NMR spectrum of 6, one quartet (δ 3.56 ppm) and
one triplet (δ 0.69 ppm) characterize the ethoxyl group on Al,
while for 7 the OSiMe3 proton resonance is observed as a singlet
(δ -0.16 ppm). In the mass spectra of both 6 and 7 the
molecular ion is detected with moderate intensity.
(14) (a) Jancik, V.; Pineda, L. W.; Pinkas, J.; Roesky, H. W.; Neculai,
D.; Neculai, A. M.; Herbst-Irmer, R. Angew. Chem., Int. Ed. 2004, 43, 2142–
2145. (b) Pineda, L. W.; Jancik, V.; Roesky, H. W.; Neculai, D.; Neculai,
A. M. Angew. Chem., Int. Ed. 2004, 43, 1419–1421. (c) Singh, S.; Jancik,
V.; Roesky, H. W.; Herbst-Irmer, R. Inorg. Chem. 2006, 45, 949–951.
(15) Mason, M. R.; Smith, J. M.; Bott, S. G.; Barron, A. R. J. Am. Chem.
Soc. 1993, 115, 4971–4984.
Crystalline solids of 2-7 were obtained in moderate yield
from toluene or hexane solutions. In contrast, L1AlMe(Cl) (1)

Organoaluminum Hydroxides
Organometallics, Vol. 27, No. 4, 2008 771
Figure 1. Molecular structure of 10. Thermal ellipsoids are drawn at the 50% level, and all hydrogen atoms, except those of the OH groups,
and one benzene solvent molecule are omitted for clarity.
Figure 3. Molecular structure of 12. Thermal ellipsoids are drawn
at the 50% level, and all hydrogen atoms, except that of the OH
group, are omitted for clarity.
Figure 2. Molecular structure of 11. Thermal ellipsoids are drawn
at the 50% level, and all hydrogen atoms, except that of the OH
group, and two THF solvent molecules are omitted for clarity.
analysis, and multinuclear NMR spectra. The 1H NMR spectra
of 14-19 exhibit one characteristic singlet (δ 5.43–5.54 ppm)
attributed to two symmetry-related Cp groups, comparable to
that in L2AlEt(µ-O)ZrMeCp2 (δ 5.30 ppm).11 Another singlet
characterizes the Me group on Zr; this resonance is devoid of
NOE correlations with protons of the Al-bound R group,
indicating that the -O-Zr-Me linkage is stretched away from
the Al atom. The compounds containing the bulky 2,6-iPr2C6H3
substituent (14, 17-19) possess considerable thermal stability
with high melting points (376–391 °C), corresponding well to
L2AlMe(µ-O)ZrMeCp2 (385 °C, dec)3 and L2AlEt(µ-O)ZrMe-
Cp2 (368–369 °C).11 In contrast, the melting points of L1AlEt(µ-
O)ZrMeCp2 (15) and L1AlPh(µ-O)ZrMeCp2 (16) are relatively
low (145–195 °C). Furthermore, in comparison to L2AlMe(µ-
3
O)ZrMeCp2 and L2AlEt(µ-O)ZrMeCp2,11 compounds 14-19
are well soluble in benzene. These observations demonstrate
Figure 4. Molecular structure of 13. Thermal ellipsoids are drawn
at the 50% level, and all hydrogen atoms, except those of the OH
group, are omitted for clarity.
accordingly that the variation of the ligand and the substituent
on aluminum exhibit a profound impact on the physical and
chemical properties of the M-O-M′ species.
Structural Characterization of 10–13 and 17. Molecular
structures of 10–13 and 17 (Figures 1–5) were determined by
single-crystal X-ray diffraction studies, with details for crystal
data and structure refinement presented in Table 1 and selected
bond lengths and angles provided in Table 2.
L1AlPh(OH) (10) crystallizes as a centrosymmetric dimer (see
Figure 1), which is in good agreement with the observation in
the mass spectrum and the monomer–dimer equilibrium ob-
served by NMR. The structure of 10 contains two Al atoms
linked by µ-OH bridges to form a perfect planar four-membered

772 Organometallics, Vol. 27, No. 4, 2008
Yang et al.
intermediate between those of L2AlMe(OH) (96.3(1)°)3 and
L2AlEt(OH) (95.32(8)°).11 The phenyl group on Al is almost
perpendicular to the NCCN quasi-plane, and the Al-C bond
length (1.9694(15) Å) is shorter than that in 10 (1.9946(18) Å)
and more comparable to those in AlPh3 (1.960, 1.956 Å).18
L2AlOEt(OH) (12) crystallizes in the monoclinic space group
P2(1)/c (see Figure 3). The aluminum atom is coordinate to
two N atoms (from chelating ꢀ-diketiminato ligand) and two O
atoms (from the OH and OEt substituents) in a distorted
tetrahedral geometry. The Al-OH bond length (1.7631(13) Å)
is much longer than the Al-OEt separation (1.7023(12) Å) and
also longer than that in L2AlEt(OH) (1.7409(17) Å).11 The
N(1)-Al-N(2) bite angle (97.11(6)°) is wider than that in
L2AlEt(OH) (95.32(8)°).11 The O-Al-O angle (115.48(6)°) is
close to that in L2Al(OH)2 (115.38(8)°).6
L2AlOSiMe3(OH) (13) crystallizes in the monoclinic space
group P2(1) (see Figure 4). Similarly, the aluminum site is also
surrounded by two N atoms and two O atoms. Both Al-O bond
lengths are nearly identical (1.7116(11), 1.7106(11) Å) and also
similar to those in L2Al(OH)2 (1.695(15), 1.711(16) Å).6 The
N(1)-Al-N(2) bite angle (96.32(5)°) is close to that in 11
(95.89(5)°). The O-Al-O angle (109.80(6)°) is slightly nar-
rower than that in [L2Al(OH)]2(µ-O) (112.33(14)°)7 and
L2Al(OH)2 (115.38(8)°).6
Figure 5. Molecular structure of 17. Thermal ellipsoids are drawn
at the 50% level, and all hydrogen atoms and one-half n-hexane
solvent molecule are omitted for clarity.
Al2O2 ring. The same bridging mode of hydroxyl groups
9
has been observed in [L2AlCl(µ-OH)]2 and [{Mes2Al(µ-
OH)}2] · 2THF.16 Altogether, the Al atom is five-coordinate with
a coordination sphere made up by two N atoms of the
ꢀ-diketiminato ligand, two O atoms of hydroxyl groups, and a
phenyl group. The bond lengths of Al-(µ-OH) (1.8825(12),
1.8583(12) Å) are comparable to those in [L2AlCl(µ-OH)]2
(1.886(1), 1.875(1) Å),9 but longer than those found for the four-
coordinate aluminum in [{Mes2Al(µ-OH)}2] · 2THF (1.822 Å)16
and [(tBu)2Al(µ-OH)]3 (1.846(3)-1.851(2) Å).15 Likewise, the
O-Al-O angle (72.82(6)°) is very close to that in [L2AlCl(µ-
OH)]2 (72.46(7)°),9 but significantly narrower than those in
[{Mes2Al(µ-OH)}2] · 2THF (80.8°),16 [(tBu)2Al(µ-OH)]3
(97.9(2)-98.1(2)°),15 and [L2Al(OH)]2(µ-O) (112.33(14)°).7 The
N(1)-Al-N(2) bite angle (89.98(6)°) is similar to that in
[L2AlCl(µ-OH)]2 (90.05(6)°),9 while the angle at oxygen
(107.18(6)°) lies between those in [{Mes2Al(µ-OH)}2] · 2THF
(98.8°)16 and [H2Al(µ-OH)]3 (127.8°).17 The two phenyl groups
on Al are arranged trans with respect to the Al2O2 plane, and
the Al-C bond length (1.9946(18) Å) is noticeably longer
than those in AlPh3 (1.960, 1.956 Å)18 and in [Ph2Al ·
NdCPh · C6H4Br]2 · 2C6H6 (1.979(13), 1.956 (13) Å).19
L2AlPh(µ-O)ZrMeCp2 (17) crystallizes in the monoclinic
space group C2/c (see Figure 5) and shows again a monomeric
arrangement, in which the terminal OH group of 11 is replaced
by a µ-oxo-linked ZrCp2Me moiety. The angle for the bent
Al-O-Zr linkage is 155.73(6)°, which is a little tighter than
that of L2AlMe(µ-O)ZrMeCp2 (158.2(1)°),3 but much wider than
that of L2AlEt(µ-O)ZrMeCp2 (144.41(6)°),11 while correspond-
ingly the Zr-O bond separation (1.9400(9) Å) falls between
those of L2AlMe(µ-O)ZrMeCp2 (1.929(2) Å)3 and L2AlEt(µ-
O)ZrMeCp2 (1.9424(10) Å).11 Similarly, the Al-O bond length
(1.7171(10) Å) lies between those of its alkyl analogues
(1.7285(10), 1.711(2) Å).3,11 These observations indicate that
the steric demand of R on Al offers a possibility for tuning the
Al-O-Zr angle and the Al-Zr separation (Scheme 3). The
Al-C bond length (1.9759(15) Å) is slightly longer relative to
that in its hydroxide precursor 11 (1.9694(15) Å). The methyl
group on Zr and the phenyl group on Al are arranged in a trans
conformation to each other, similar to what is found in the ethyl
analogue.11 The XCp1-Zr-XCp2 angle and the Zr-XCp distances
are in the expected range.
In contrast to 10, the X-ray crystal structural analysis of
L2AlPh(OH) (11) shows a monomeric composition (see Figure
2), again in agreement with the observations in the mass and
NMR spectra. This is most likely due to the bulkier L2 ligand,
in which the Ar substituents cannot be packed against each other
into a dimer as that of the flat mesityl substituent of L1. Here,
the four-coordinate Al atom is surrounded by two N atoms of
the ꢀ-diketiminato ligand, an OH, and a phenyl group. Conse-
quently, the Al-OH separation (1.7202(10) Å) is much shorter
than those in 10 (1.8825(12), 1.8583(12) Å) and slightly shorter
than those found in the alkyl-substituted terminal hydroxides
L2AlMe(OH) (1.731(3) Å)3 and L2AlEt(OH) (1.7409(17) Å),11
but a little longer than those of the dihydroxides L2Al(OH)2
(1.695(15), 1.711(16) Å).6 The N(1)-Al-N(2) bite angle
(95.89(5)°) is much wider than that in 10 (89.98(6)°) and
Ethylene Polymerization Studies with Compound 17.
Table 3 summarizes the polymerization results of compound
17. All polymeric materials were isolated as white powders.
Under comparable polymerization conditions, the methylalu-
moxane (MAO)/17 catalyst system shows lower activity com-
pared to that of MAO/L2AlR(µ-O)MMeCp2 (R ) Me, Et; M
) Ti,5e Zr3,11). However the MAO-activated compound 17 still
exhibits moderate catalytic activity for the polymerization of
ethylene. It can be observed that the catalytic activity of
compound L2AlR(µ-O)ZrMeCp2 varies depending on the R
group on the aluminum center. The activity is in the order Me
> Et > Ph. This can be attributed to the steric and electronic
factors that stabilize the cation formation.
Conclusion
New organoaluminum hydroxides LAlR(OH) (L ) L3, R )
Me, 8; L ) L1, R ) Et, 9; L ) L1, R ) Ph, 10; L ) L2, R )
Ph, 11; L ) L2, R ) OEt, 12; L ) L2, R ) OSiMe3, 13) were
synthesized by controlled hydrolysis of the respective chlorides.
In contrast to the chlorides and depending on the steric bulk of
(16) Storre, J.; Klemp, A.; Roesky, H. W.; Schmidt, H.-G.; Noltemeyer,
M.; Fleischer, R.; Stalke, D. J. Am. Chem. Soc. 1996, 118, 1380–1386.
(17) Rogers, J. H.; Apblett, A. W.; Cleaver, W. M.; Tyler, A. N.; Barron,
A. R. J. Chem. Soc., Dalton Trans. 1992, 3179–3187.
(18) Malone, J. F.; McDonald, W. S. Chem. Commun. 1967, 444–445.
(19) McDonald, W. S. Acta Crystallogr. 1969, B25, 1385–1391.

Organoaluminum Hydroxides
Organometallics, Vol. 27, No. 4, 2008 773
Table 1. Crystal Data and Structure Refinement for Compounds 10 · (benzene)0.5, 11 · (THF)2, 12, 13, and 17 · (n-hexane)0.5
10 · (benzene)0.5
11 · (THF)2
662282
12
13
17 · (n-hexane)0.5
CCDC
formula
fw
662281
662283
662284
662285
C32H38AlN2O
493.62
C43H63AlN2O3
682.93
C31H47AlN2O2
506.69
C32H51AlN2O2Si
550.82
C49H66AlN2OZr
817.24
T, K
100(2)
100(2)
100(2)
100(2)
100(2)
cryst syst
space group
a, Å
b, Å
c, Å
triclinic
P1
triclinic
P1
monoclinic
P2(1)/c
16.954(2)
10.0454(15)
17.892(3)
90
103.031(2)
90
2968.7(7)
4
monoclinic
P2(1)
8.8703(10)
19.895(2)
10.2310(11)
90
114.0800(10)
90
1648.4(3)
2
monoclinic
C2/c
37.4042(15)
12.8409(5)
19.3062(8)
90
104.05
90
8995.4(6)
8
1.270
¯
¯
11.4187(11)
11.5317(11)
12.1602(11)
93.6510(10)
106.2490(10)
114.6840(10)
1366.5(2)
9.0526(10)
12.0803(14)
18.727(2)
73.6670(10)
82.3990(10)
86.1870(10)
1947.1(4)
R, deg
ꢀ, deg
γ, deg
V, Å3
Z
2
2
F
calc, g/cm3
1.200
0.101
1.165
0.092
1.134
0.097
1.110
0.127
µ, mm-1
0.300
cryst size, mm3
0.1 × 0.1 × 0.05
1.78 to 26.40
-14 e h e 13
-14 e k e 14
0 e l e 15
25 588
0.4 × 0.2 × 0.2
2.75 to 25.08
-10 e h e 10
-13 e k e 14
0 e l e 22
36 861
0.25 × 0.1 × 0.05
2.34 to 25.59
-20 e h e 20
0 e k e 12
0 e l e 21
5557
0.15 × 0.1 × 0.05
2.05 to 26.37
-11 e h e 10
0 e k e 24
0 e l e 12
6706
0.4 × 0.4 × 0.2
2.64 to 26.39
-46 e h e 46
-16 e k e 16
-24 e l e 24
95 350
θ range for data collection, deg
index ranges
no. of reflns collected
no. of indep reflns [Rint
]
5606 [0.0306]
5606/1/336
1.043
0.0392, 0.0948
0.0571, 0.1041
0.286/-0.292
6895 [0.0205]
6895/0/444
1.047
0.0388, 0.1039
0.0427, 0.1073
0.478/-0.410
5557 [0.0430]
5557/1/339
1.020
0.0379, 0.0905
0.0542, 0.0982
0.317/-0.268
6706 [0.0263]
6706/16/386
1.031
0.0337, 0.0778
0.0482, 0.0856
0.255/-0.272
9178 [0.0206]
9178/146/569
1.043
0.0255, 0.0672
0.0271, 0.0685
0.773/-0.656
no. of data/restrnts/params
goodness-of-fit on F2
R1, wR2 (I > 2σ(I))
R1, wR2 (all data)
largest diff peak/hole, e Å-3
Table 2. Selected Bond Distances (Å) and Angles (deg) for Compounds 10-13 and 17
10
11
12
13
17
Al-O(1)
1.8825(12)
1.8583(12)
1.9937(14)
1.9736(14)
1.9946(18)
1.7202(10)
1.7631(13)
1.7023(12)
1.8885(14)
1.8885(14)
1.7116(11)
1.7106(11)
1.868(4)
1.7171(10)
Al-O(2)
Al-N(1)
1.9120(12)
1.9153(12)
1.9694(15)
1.9121(12)
1.9107(12)
1.9759(15)
1.9400(9)
2.258
Al-N(2)
1.899(4)
Al-C
Zr-O
Zr-XCp1
Zr-XCp2
2.271
O(1)-Al-N(1)
O(1)-Al-N(2)
N(1)-Al-N(2)
O(1)-Al-C
C-Al-N(1)
C-Al-N(2)
Al-O-Zr
XCp1-Zr-XCp2
149.75(6)
89.84(6)
89.98(6)
103.95(6)
105.56(7)
102.97(6)
109.89(5)
112.05(5)
95.89(5)
117.76(6)
110.29(6)
108.78(6)
112.51(6)
109.03(6)
97.11(6)
111.65(19)
111.86(19)
96.32(5)
113.53(5)
114.91(5)
95.80(5)
113.55(6)
110.21(6)
107.38(6)
155.73(6)
129.23
OEt, 18; L ) L2, R ) OSiMe3, 19) by intermolecular
elimination of CH4. Compound 17 exhibits moderate catalytic
activity in ethylene polymerization. Preliminary results of
L2AlR(µ-O)ZrMeCp2 in polymerization reactions show that the
activity depends on the substituents R on aluminum.
Scheme 3
Table 3. Ethylene Polymerization for Compound 17 (22.2 µmol) in
100 mL of Toluene under 1 atm of Ethylene Pressure at 25 °C,
Activity (A) ) 105 g PE/mol cat · h
Experimental Section
General Remarks. All manipulations were carried out under
an atmosphere of purified nitrogen using standard Schlenk tech-
niques. The samples for analytical measurements as well as for
the reactions were manipulated in a glovebox. The solvents were
purified and dried using conventional procedures and were freshly
distilled under nitrogen and degassed prior to use. MeAlCl2,
EtAlCl2, nBuLi, PhLi, AlCl3, LiOEt, LiOSiMe3, and Cp2ZrMe2 were
purchased from Aldrich. LH,13,20 LLi,13,20 L2AlCl2,21 and 1,3-
MAO/17
t (min)
PE (g)
A
200
300
400
600
30
30
30
30
0.12
0.26
0.72
1.12
0.11
0.23
0.65
1.01
the ꢀ-diketiminato ligand, the hydroxides tend to dimerize under
formation of a planar Al2O2 ring. Further, the OH groups exhibit
the expected reactivity toward Cp2ZrMe2, resulting in the
formation of the oxo-bridged heterobimetallic compounds
LAlR(µ-O)ZrMeCp2 (L ) L3, R ) Me, 14; L ) L1, R ) Et,
15; L ) L1, R ) Ph, 16; L ) L2, R ) Ph, 17; L ) L2, R )
(20) Budzelaar, P. H. M.; van Oort, A. B.; Orpen, A. G. Eur. J. Inorg.
Chem. 1998, 1485–1494.
(21) Stender, M.; Eichler, B. E.; Hardman, N. J.; Power, P. P.; Prust,
J.; Noltemeyer, M.; Roesky, H. W. Inorg. Chem. 2001, 40, 2794–2799.

774 Organometallics, Vol. 27, No. 4, 2008
Yang et al.
1
diisopropyl-4,5-dimethylimidazol-2-ylidene (abbreviated as :C)22
were prepared as described in the literature.
a white solid. Yield: 0.64 g (38%); mp 133 °C. H NMR (500.13
MHz, C6D6): δ 1.51 (s, 6 H, CMe), 1.87 (s, 6 H, o-ArMe), 2.03 (s,
6 H, p-ArMe), 2.45 (s, 6 H, o-ArMe), 5.04 (s, 1 H, γ-CH), 6.57–7.72
(m, Ar) ppm. 13C NMR (75.48 MHz, C6D6): δ 171.1 (CN), 146.1
(br, i-Ph), 139.8 (i-Ar), 138.0 (o-Ph), 135.9, 134.0, 133.2, 130.1,
129.9 (p-, o-, o-, m-, m-Ar), 128.5, 127.3, (p-, m-Ph), 98.4 (γ-CH),
22.7 (ꢀ-CH3), 20.8 (p-ArMe), 19.5 (o-ArMe), 19.2 (o-ArMe) ppm.
IR (Nujol mull, cm-1): ν˜ 1610 (w), 1529 (w), 1299 (w), 1261 (w),
1246 (w), 1223 (w), 1200 (w), 1149 (w), 1090 (w), 1022 (w), 962
(w), 935 (w), 919 (w), 877 (w), 847 (w), 799 (w), 765 (w), 724
(w), 706 (w), 680 (w). EI-MS: m/z (%) 472.2 (10) [M+], 395.2
(100) [M+ - Ph], 379.1 (52) [M+ - Ph - Me]. Anal. Calcd for
C29H34AlClN2 (473.0): C, 73.63; H, 7.24; N, 5.92. Found: C, 73.31;
H, 7.50; N, 5.72.
L1AlMe(Cl) (1). To a toluene solution (40 mL) of L1H (0.84 g,
2.5 mmol) at -78 °C was added nBuLi (1 mL, 2.5 M, 2.5 mmol)
drop by drop. The mixture was stirred and allowed to warm to
room temperature. After additional stirring for 12 h, the solution
was cooled to -78 °C again and MeAlCl2 (2.5 mL, 1 M, 2.5 mmol)
was added. The resulting suspension was allowed to warm to room
temperature and stirred for 12 h. After workup, the insoluble LiCl
was removed by filtration, and the filtrate was concentrated to form
an oily paste. Washing the paste with pentane (5 mL) and drying
it in vacuum afforded a white solid. Yield: 0.28 g (27%); mp >100
1
°C (dec). H NMR (200.13 MHz, C6D6): δ-0.48 (s, 3 H, AlMe),
1.47 (s, 6 H, CMe), 2.09 (s, 6 H, p-ArMe), 2.10 (s, 6 H, o-ArMe),
2.51 (s, 6 H, o-ArMe), 4.94 (s, 1 H, γ-CH), 7.05–7.15 (m, Ar)
ppm. IR (Nujol mull, cm-1): ν˜ 1610 (w), 1530 (w), 1299 (w), 1261
(w), 1251 (w), 1225 (w), 1200 (w), 1149 (w), 1092 (w), 1023 (w),
961 (w), 936 (w), 878 (w), 799 (w), 722 (w), 672 (w), 661 (w).
EI-MS: m/z (%) 410.2 (4) [M+], 395.2 (100) [M+ - Me]. Anal.
Calcd for C24H32AlClN2 (411.0): C, 70.14; H, 7.85; N, 6.82. Found:
C, 69.82; H, 8.04; N, 6.67.
L2AlPh(Cl) (5). Preparation of 5 was accomplished like that of
4 using PhLi (2 mL, 1.8 M, 3.6 mmol), AlCl3 (0.48 g, 3.6 mmol),
and L2Li in situ (3.6 mmol) in toluene (60 mL). Yield: 0.46 g
(23%); mp 212–214 °C. 1H NMR (300.13 MHz, C6D6): δ 0.67 (d,
J ) 6.8 Hz, 6 H, CH(CH3) 2), 1.01 (d, J ) 6.8 Hz, 6 H, CH(CH3) 2),
1.16 (d, J ) 6.8 Hz, 6 H, CH(CH3) ), 1.49 (d, J ) 6.6 Hz, 6 H,
CH(CH3) ), 1.58 (s, 6 H, CMe), 3.06 (sept, J ) 6.8 Hz, 2 H,
2
2
L3AlMe(Cl) (2). Preparation of 2 was accomplished like that of
1 from L3H (0.50 g, 1 mmol), nBuLi (0.4 mL, 2.5 M, 1 mmol),
and MeAlCl2 (1 mL, 1 M, 1 mmol). Yield: 0.45 g (77%); mp
179–181 °C. 1H NMR (500.13 MHz, C6D6): δ -0.73 (s, 3 H,
AlMe), 1.10 (s, 18 H, C(CH3)3), 1.18 (d, J ) 6.6 Hz, 6 H,
CH(CH3)2), 1.22 (d, J ) 6.6 Hz, 6 H, CH(CH3)2), 1.33 (d, J ) 6.8
Hz, 6 H, CH(CH3)2), 1.44 (d, J ) 6.4 Hz, 6 H, CH(CH3)2), 3.15
(sept, J ) 6.8 Hz, 2 H, CH(CH3)2), 4.15 (sept, J ) 6.8 Hz, 2 H,
CH(CH3)2), 6.00 (s, 1 H, γ-CH), 7.00–7.15 (m, Ar) ppm. 13C NMR
(75.48 MHz, C6D6): δ 179.8 (CN), 146.1, 143.8, 141.5, 127.2,
125.0, 124.0 (o-, o-, i-, p-, m-, m-Ar), 101.8 (γ-CH), 43.32 (ꢀ-
C(CH3)3), 32.2 (ꢀ-C(CH3)3), 28.7, 28.3 (CH(CH3)2), 27.8, 26.0,
24.7, 24.3 (CH(CH3)2), -11.9 (br, AlMe) ppm. IR (Nujol mull,
cm-1): ν˜ 3063 (w), 1623 (w), 1588 (w), 1530 (w), 1486 (m), 1401
(m), 1378 (s), 1360 (s), 1317 (m), 1306 (w), 1262 (m), 1215 (w),
1180 (w), 1098 (m), 1019 (m), 934 (w), 865 (w), 802 (m), 757
(w), 722 (w), 697 (w), 656 (w). EI-MS: m/z (%) 578.4 (6) [M+],
563.4 (100) [M+ - Me]. Anal. Calcd for C36H56AlClN2 (579.3):
C, 74.64; H, 9.74; N, 4.84. Found: C, 74.37; H, 9.74; N, 4.63.
L1AlEt(Cl) (3). Preparation of 3 was accomplished like that of
1 from L1H (0.84 g, 2.5 mmol), nBuLi (1 mL, 2.5 M, 2.5 mmol),
and EtAlCl2 (1.3 mL, 1.9 M, 2.5 mmol). Yield: 0.68 g (64%); mp
CH(CH3) 2), 3.72 (sept, J ) 6.8 Hz, 2 H, CH(CH3)2), 5.02 (s, 1 H,
γ-CH), 6.95–7.05 (m, Ar), 7.05–7.20 (m, Ar), 6.98–7.40 (m, Ar)
ppm. 13C NMR (125.8 MHz, C6D6): δ 171.6 (CN), 144.0 (br, i-Ph),
145.1, 144.3, 139.7 (o-, o-, i-Ar), 137.9, 127.9, 127.8, (o-, p-, m-Ph),
127.1, 125.0, 124,5 (p-, m-, m-Ar), 98.9 (γ-CH), 28.9, 28.8
(CH(CH3)2), 25.7, 24.7, 24.5, 23.9 (CH(CH3)2), 23.5 (ꢀ-CH3) ppm.
IR (Nujol mull, cm-1): ν˜ 3055 (m), 1584 (w), 1532 (m), 1317 (m),
1260 (m), 1197 (w), 1178 (w), 1100 (m), 1089 (m), 1056 (m), 1025
(m), 934 (w), 881 (w), 800 (m), 758 (w), 736 (w), 722 (w), 704
(w), 676 (w), 648 (w). EI-MS: m/z (%) 521 (4) [M+-Cl], 478 (44)
[M+ - Ph], 463 (100) [M+ - Ph - Me]. Anal. Calcd for
C35H46AlClN2 (557.2): C, 75.45; H, 8.32; N, 5.03. Found: C, 75.07;
H, 8.48; N, 4.93.
L2AlOEt(Cl) (6). A solution of LiOEt (5 mL, 1 M, 5 mmol)
was added in excess drop by drop at -78 °C to a solution of
L2AlCl2 (2.06 g, 4 mmol) in THF (80 mL). The mixture was
allowed to warm to room temperature and stirred overnight. After
workup the solvent was removed in vacuo and the crude product
was extracted with Et2O (90 mL). The solution was concentrated
to 10 mL and was kept at 4 °C to afford a crystalline solid. Yield:
1
1.62 g (77%); mp 155–157 °C. H NMR (500.13 MHz, C6D6): δ
0.69 (t, 3 H, OCH2CH3), 1.08 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.16
(d, J ) 6.8 Hz, 6 H, CHMe2), 1.45 (d, J ) 6.8 Hz, 6 H, CHMe2),
1.49 (d, J ) 6.6 Hz, 6 H, CHMe2), 1.53 (s, 6 H, CMe), 3.37 (sept,
1
165–167 °C. H NMR (300.13 MHz, C6D6): δ 0.08 (q, J ) 8.2
Hz, 2 H, AlCH2CH3), 0.89 (t, J ) 8.0 Hz, 3 H, AlCH2CH3), 1.47
(s, 6 H, CMe), 2.08 (s, 6 H, p-ArMe), 2.10 (s, 6 H, o-ArMe), 2.52
(s, 6 H, o-ArMe), 4.95 (s, 1 H, γ-CH), 6.75–7.15 (m, Ar) ppm. 13
C
J ) 6.8 Hz, 2 H, CHMe2) 3.56 (q, 2 H, J ) 6.9 Hz, OCH2CH3),
3.57 (sept, J ) 6.7 Hz, 2 H, CHMe2), 4.87 (s, 1 H, γ-CH), 7.10–7.16
(m, Ar) ppm. 13C NMR (125.76 MHz, C6D6): δ 171.3 (CN), 145.3,
144.6, 139.0, 127.8, 125.0, 124.3 (o-, o-, i-, p-, m-, m-Ar), 97.8
(γ-CH), 58.7 (OCH2CH3), 28.9, 28.2 (CH(CH3)2), 26.4, 24.9, 24.8,
24.3 (CH(CH3)2), 23.3 (ꢀ-CH3), 20.1 (OCH2CH3) ppm. IR (Nujol
mull, cm-1): ν˜ 3057 (w), 1623 (w), 1589 (w), 1553 (m), 1533 (s),
1317 (s), 1305 (m), 1253 (m), 1169 (s), 1144 (m), 1104 (w), 1075
(w), 1056 (w), 1023 (m), 936 (w), 919 (w), 890 (w), 801 (m), 775
(w), 759 (w), 721 (w), 690 (w). EI-MS: m/z (%) 524.2 (40) [M+],
509.2 (16) [M+ - Me], 463.2 (100) [M+ - OEt - Me]. Anal.
Calcd for C31H46AlClN2O (525.1): C, 70.90; H, 8.83; N, 5.33.
Found: C, 70.63; H, 8.93; N, 5.30.
NMR (75.48 MHz, C6D6): δ 170.3 (CN), 139.8, 135.9, 134.6, 132.8,
130.4, 129.4 (i-, p-, o-, o-, m-, m-Ar), 98.0 (γ-CH), 22.4 (ꢀ-CH3),
20.8 (p-ArMe), 19.6 (o-ArMe), 18.6 (o-ArMe), 8.7 (AlCH2CH3),
0.66 (AlCH2CH3) ppm. IR (Nujol mull, cm-1): ν˜ 1728 (w), 1608
(s), 1532 (s), 1299 (s), 1262 (s), 1245 (s), 1223 (s), 1198 (s), 1147
(s), 1094 (m), 1021 (s), 996 (s), 955 (m), 936 (m), 875 (s), 845
(m), 801 (m), 761 (s), 723 (m), 655 (m), 607 (s), 566 (s). EI-MS:
m/z (%) 395.2 (100) [M+ - Et]. Anal. Calcd for C25H34AlClN2
(425.0): C, 70.65; H, 8.06; N, 6.59. Found: C, 70.26; H, 8.40; N,
6.50.
L1AlPh(Cl) (4). A solution of PhLi (2 mL, 1.8 M, 3.6 mmol)
was added at -78 °C to the suspension of AlCl3 (0.48 g, 3.6 mmol)
in toluene (30 mL). The mixture was allowed to warm to room
temperature, and a white precipitate was observed immediately.
After stirring this mixture overnight, a toluene solution (40 mL) of
L1Li (3.6 mmol) in situ was added at -78 °C. After removing the
cold bath and raising the temperature to room temperature, stirring
was continued for another 12 h. After filtration, the filtrate was
evaporated to dryness and washed with n-pentane (10 mL) to afford
L2AlOSiMe3(Cl) (7). A solution of LiOSiMe3 (1 mL, 1 M, 1
mmol) was added drop by drop at -78 °C to a solution of L2AlCl2
(0.51 g, 1 mmol) in toluene (50 mL). The mixture was allowed to
warm to room temperature and stirred overnight. After filtration
the solution was removed in vacuo to afford a white solid. Yield:
1
0.41 g (72%); mp 240–242 °C. H NMR (500.13 MHz, C6D6): δ
-0.16 (s, 9 H, SiMe3), 1.03 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.17 (d,
J ) 6.8 Hz, 6 H, CHMe2), 1.41 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.50
(d, J ) 6.6 Hz, 6 H, CHMe2), 1.52 (s, 6 H, CMe), 3.30 (sept, J )
(22) Kuhn, N.; Kratz, T. Synthesis 1993, 561–562.

Organoaluminum Hydroxides
Organometallics, Vol. 27, No. 4, 2008 775
7.0 Hz, 2 H, CHMe2), 3.62 (sept, J ) 6.6 Hz, 2 H, CHMe2), 4.87
(s, 1 H, γ-CH), 7.10–7.16 (m, Ar) ppm. 13C NMR (125.76 MHz,
C6D6): δ 171.5 (CN), 145.6, 143.8, 139.0, 127.7, 125.2, 124.0 (o-,
o-, i-, p-, m-, m-Ar), 97.7 (γ-CH), 29.0, 28.0 (CH(CH3)2), 26.8,
24.7, 24.7, 24.2 (CH(CH3)2), 23.3 (ꢀ-CH3), 2.4 (Si(CH3)3) ppm.
29Si NMR (99.36 MHz, C6D6): δ 4.43 ppm. IR (Nujol mull, cm-1):
ν˜ 3585 (w), 1938 (w), 1870 (w), 1585 (w), 1528 (w), 1319 (m),
1302 (w), 1255 (w), 1179 (w), 1166 (w), 1098 (w), 1054 (m), 1020
(w), 968 (w), 934 (w), 892 (w), 854 (w), 836 (w), 799 (w), 757
(w), 660 (w). EI-MS: m/z (%) 568.3 (24) [M+], 553.2 (100) [M+
- Me]. Anal. Calcd for C32H50AlClN2OSi (569.3): C, 67.51; H,
8.85; N, 4.92. Found: C, 67.32; H, 8.79; N, 4.77.
(s, 6 H, o-ArMe), 2.07 (s, 6 H, p-ArMe), 2.49 (s, 6 H, o-ArMe),
4.99 (s, 1 H, γ-CH), 6.50–8.04 (m, Ar) ppm. 13C NMR (75.48 MHz,
C6D6, primary conformation): δ 169.1 (CN), 145.7–125.6 (Ph, Ar),
99.8 (γ-CH), 23.9 (ꢀ-CH3), 22.6 (o-ArMe), 21.4 (p-ArMe), 20.9
(o-ArMe) ppm. IR (Nujol mull, cm-1): ν˜ 3671 (w, OH), 3055 (w),
1610 (w), 1538 (w), 1510 (w), 1290 (w), 1261 (w), 1243 (w), 1220
(w), 1199 (w), 1146 (w), 1085 (w), 1019 (w), 919 (w), 859 (w),
800 (w), 728 (w), 705 (w), 669 (w). EI-MS: m/z (%), 813.4 (100)
[2M+ - Ph - Me - 3H], 753.4 (56) [2M+ - 2Ph - H], 454.2
(4) [M+], 437.2 (14) [M+ - OH], 377.2 (66) [M+ - Ph]. Anal.
Calcd for C29H35AlN2O (454.6): C, 76.62; H, 7.76; N, 6.16. Found:
C, 76.24; H, 7.71; N, 5.88. X-ray quality crystals of 10 · (benzene)0.5
were grown from the solution of benzene.
L3AlMe(OH) (8). To a mixture of L3AlMe(Cl) (2) (0.39 g, 0.68
mmol) and [CN(iPr)C2Me2N(iPr)] (:C, 0.12 g, 0.68 mmol) in
toluene (40 mL) at 0 °C was added distilled H2O (12 µL, 0.68
mmol). The suspension was allowed to warm to room temperature
and stirred for 12 h. The insoluble solid was removed by filtration,
and from the filtrate all volatiles were removed in vacuo. The
resulting residue was washed with n-pentane (3 mL) to afford a
white solid. Yield: 0.27 g (70%); mp >197 °C (dec). 1H NMR
(500.13 MHz, C6D6): δ -1.00 (s, 3 H, AlMe), 0.63 (s, 1 H, OH),
1.10 (s, 18 H, C(CH3)3), 1.26 (d, J ) 6.8 Hz, 6 H, CH(CH3)2),
1.27 (d, J ) 6.8 Hz, 6 H, CH(CH3)2), 1.36 (d, J ) 6.4 Hz, 6 H,
CH(CH3)2), 1.37 (d, J ) 6.8 Hz, 6 H, CH(CH3)2), 3.22 (sept, J )
6.8 Hz, 2 H, CH(CH3)2), 4.03 (sept, J ) 6.8 Hz, 2 H, CH(CH3)2),
5.71 (s, 1 H, γ-CH), 7.00–7.20 (m, Ar) ppm. 13C NMR (125.8 MHz,
C6D6): δ 178.0 (CN), 145.6, 143.7, 142.3, 126.8, 124.6, 123.9 (o-,
o-, i-, p-, m-, m-Ar), 99.0 (γ-CH), 43.0 (ꢀ-C(CH3)3), 32.5 (ꢀ-
C(CH3)3), 28.7, 28.1 (CH(CH3)2), 27.4, 25.9, 24.6, 24.2 (CH(CH3)2),
-13.5 (br, AlMe) ppm. IR (Nujol mull, cm-1): ν˜ 3732 (w, OH),
1621 (w), 1529 (w), 1502 (w), 1401 (w), 1364 (w), 1315 (w), 1274
(w), 1262 (w), 1216 (w), 1187 (w), 1156 (w), 1138 (w), 1096 (w),
1029 (w), 1020 (w), 933 (w), 847 (w), 805 (w), 784 (w), 754 (w),
722 (w), 694 (w). EI-MS: m/z (%) 560.4 (4) [M+], 545.4 (100)
[M+ - Me]. Anal. Calcd for C36H57AlN2O (560.8): C, 77.10; H,
10.24; N, 4.99. Found: C, 76.73; H, 10.10; N, 4.95.
L2AlPh(OH) (11). Preparation of 11 was accomplished like that
of 9 from L2AlPh(Cl) (5) (1.11 g, 2 mmol), [CN(iPr)C2Me2N(iPr)]
(:C, 0.36 g, 2 mmol), and distilled H2O (36 µL, 2 mmol). Yield:
1
0.49 g (45%); mp 192 °C. H NMR (500.13 MHz, C6D6): δ 0.63
(s, 1 H, OH), 0.68 (t, J ) 6.8, 6 H, CH(CH3)2), 1.05 (d, J ) 6.8
Hz, 6 H, CH(CH3)2), 1.20 (d, J ) 7.0 Hz, 6 H, CH(CH3)2), 1.40
(d, J ) 6.8 Hz, 6 H, CH(CH3)2), 1.61 (s, 6 H, CMe), 3.09 (sept, J
) 6.8 Hz, 2 H, CH(CH3)2), 3.76 (sept, J ) 6.8 Hz, 2 H, CH(CH3)2),
4.98 (s, 1 H, γ-CH), 7.00–7.19 (m, Ar) ppm. 13C NMR (125.8 MHz,
C6D6): δ 170.3 (CN), 146.8 (br, i-Ph), 145.1, 144.3, 140.7 (o-, o-,
i-Ar), 138.0, 127.7 (o-, p-Ph), 127.4 (p-Ar), 126.9 (m-Ph), 124.7,
124,4 (m-, m-Ar), 97.7 (γ-CH), 28.8, 28.4 (CH(CH3)2), 25.5, 24.7,
24.6, 23.8 (CH(CH3)2), 23.3 (ꢀ-CH3) ppm. IR (Nujol mull, cm-1):
ν˜ 3720 (w, OH), 3053 (w), 1623 (w), 1584 (w), 1533 (w), 1317
(w), 1257 (w), 1197 (w), 1179 (w), 1101 (w), 1085 (w), 1056 (w),
1025 (w), 935 (w), 880 (w), 800 (w), 785 (w), 759 (w), 734 (w),
708 (w), 674 (w). EI-MS: m/z (%) 537.4 (28) [M+ - H], 521.4
(100) [M+ - Me - 2H]. Anal. Calcd for C35H47AlN2O (538.7):
C, 78.03; H, 8.79; N, 5.20. Found: C, 77.91; H, 8.85; N, 5.20. X-ray
quality crystals of 11 · (THF)2 were grown from the solution of THF.
L2AlOEt(OH) (12). Preparation of 12 was accomplished like
that of 8 from L2AlOEt(Cl) (6) (1.05 g, 2 mmol), [CN(iPr)C2Me2-
N(iPr)] (:C, 0.36 g, 2 mmol), and distilled H2O (36 µL, 2 mmol).
Yield: 0.22 g (22%); mp 146–148 °C. 1H NMR (500.13 MHz,
C6D6): δ 0.59 (s, 1 H, OH), 0.67 (t, 3 H, OCH2CH3), 1.14 (d, J )
6.8 Hz, 6 H, CHMe2), 1.17 (d, J ) 6.6 Hz, 6 H, CHMe2), 1.36 (d,
J ) 6.6 Hz, 6 H, CHMe2), 1.48 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.57
(s, 6 H, CMe), 3.38 (sept, J ) 6.8 Hz, 2 H, CHMe2) 3.46 (q, 2 H,
J ) 6.8 Hz, OCH2CH3), 3.54 (sept, J ) 6.8 Hz, 2 H, CHMe2),
4.90 (s, 1 H, γ-CH), 7.10–7.16 (m, Ar) ppm. 13C NMR (125.76
MHz, C6D6): δ 170.3 (CN), 144.9, 144.6, 140.0, 127.3, 124.4, 124.2
(o-, o-, i-, p-, m-, m-Ar), 96.6 (γ-CH), 58.4 (OCH2CH3), 28.8, 28.0
(CH(CH3)2), 25.8, 24.8, 24.7, 24.5 (CH(CH3)2), 23.1 (ꢀ-CH3), 20.6
(OCH2CH3)) ppm. IR (Nujol mull, cm-1): ν˜ 3733 (w, OH), 3176
(w), 1584 (w), 1552 (w), 1533 (m), 1319 (m), 1252 (w), 1197 (w),
1169 (w), 1144 (w), 1103 (w), 1073 (w), 1056 (w), 1022 (w), 936
(w), 913 (w), 890 (w), 801 (w), 776 (w), 765 (w), 759 (w), 722
(w), 675 (w). EI-MS: m/z (%) 506.3 (64) [M+], 445.3 (100) [M+
- Et - 2Me - 2H]. Anal. Calcd for C31H47AlN2O2 (506.7): C,
73.48; H, 9.35; N, 5.53. Found: C, 73.13; H, 9.58; N, 5.39.
L2AlOSiMe3(OH) (13). Preparation of 13 was accomplished like
that of 8 from L2AlOSiMe3(Cl) (7) (1.14 g, 2 mmol), [CN(iPr)C2Me2-
N(iPr)] (:C, 0.36 g, 2 mmol), and distilled H2O (36 µL, 2 mmol).
L1AlEt(OH) (9). Preparation of 9 was accomplished like that
of 8 from L1AlEt(Cl) (3) (0.42 g, 1 mmol), [CN(iPr)C2Me2N(iPr)]
(:C, 0.18 g, 1 mmol), and distilled H2O (18 µL, 1 mmol). Yield:
0.18 g (44%); mp 158–159 °C. 1H NMR (500.13 MHz, C6D6) for
the primary conformation: δ -0.05 (q, J ) 8.0 Hz, 2 H,
AlCH2CH3), 0.54 (s, 1H, OH), 0.78 (t, J ) 8.0 Hz, 3 H, AlCH2CH3),
1.51 (s, 6 H, CMe), 2.11 (s, 6 H, p-ArMe), 2.16 (s, 6 H, o-ArMe),
2.51 (s, 6 H, o-ArMe), 4.91 (s, 1 H, γ-CH), 6.78–7.15 (m, Ar)
ppm; for the second conformation: δ 0.23 (q, J ) 8.0 Hz, 2 H,
AlCH2CH3), 1.27 (s, 1H, OH), 1.35 (s, 6 H, CMe), 1.55 (t, J ) 8.0
Hz, 3 H, AlCH2CH3), 2.04 (s, 6 H, o-ArMe), 2.16 (s, 6 H, o-ArMe),
2.28 (s, 6 H, p-ArMe), 4.91 (s, 1 H, γ-CH), 6.78–7.15 (m, Ar)
ppm. 13C NMR (75.48 MHz, C6D6, primary conformation): δ 169.1
(CN), 140.9, 135.4, 134.7, 132.9, 130.0, 129.3 (i-, p-, o-, o-, m-,
m-Ar), 96.6 (γ-CH), 22.3 (ꢀ-CH3), 20.9 (p-ArMe), 19.1 (o-ArMe),
18.4 (o-ArMe), 9.3 (AlCH2CH3), -0.78 (br, AlCH2CH3) ppm. IR
(Nujol mull, cm-1): ν˜ 3672 (s, OH), 1766 (w), 1738 (w), 1609
(w), 1534 (s), 1287 (m), 1262 (m), 1244 (m), 1221 (m), 1198 (m),
1145 (m), 1094 (m), 1021 (s), 991 (m), 919 (s), 859 (s), 800 (m),
765 (m), 723 (m). EI-MS: m/z (%) 406.3 (>1) [M+], 389.3 (>1)
[M+ - OH], 377.2 (100) [M+ - Et]. Anal. Calcd for C25H35AlN2O
(406.5): C, 73.86; H, 8.68; N, 6.89. Found: C, 73.49; H, 8.41; N,
6.62.
1
Yield: 0.49 g (44%); mp 192 °C. H NMR (500.13 MHz, C6D6):
δ -0.24 (s, 9 H, SiMe3), 0.58 (s, OH), 1.09 (d, J ) 6.8 Hz, 6 H,
CHMe2), 1.17 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.36 (d, J ) 6.8 Hz,
6 H, CHMe2), 1.42 (d, J ) 6.6 Hz, 6 H, CHMe2), 1.55 (s, 6 H,
CMe), 3.28 (sept, J ) 6.8 Hz, 2 H, CHMe2), 3.56 (sept, J ) 6.8
Hz, 2 H, CHMe2), 4.88 (s, 1 H, γ-CH), 7.11–7.16 (m, Ar) ppm.
13C NMR (125.76 MHz, C6D6): δ 170.4 (CN), 144.9, 143.9, 139.9,
127.3, 124.6, 124.0 (o-, o-, i-, p-, m-, m-Ar), 96.7 (γ-CH), 28.7,
27.8 (CH(CH3)2), 25.9, 24.6, 24.5, 24.4 (CH(CH3)2), 23.1 (ꢀ-CH3),
2.6 (Si(CH3)3) ppm. 29Si NMR (99.36 MHz, C6D6): δ 2.02 ppm.
IR (Nujol mull, cm-1): ν˜ 3730 (m, OH), 3062 (m), 1938 (w), 1870
L1AlPh(OH) (10). Preparation of 10 was accomplished like that
of 9 from L1AlPh(Cl) (4) (0.95 g, 2 mmol), [CN(iPr)C2Me2N(iPr)]
(:C, 0.36 g, 2 mmol), and distilled H2O (36 µL, 2 mmol). Yield:
0.44 g (48%); mp 203–205 °C. 1H NMR (500.13 MHz, C6D6) for
the primary conformation: δ 1.39 (s, 6 H, CMe), 1.52 (s, 6 H,
o-ArMe), 1.79 (s, 1H, OH), 2.16 (s, 6 H, p-ArMe), 2.25 (s, 6 H,
o-ArMe), 5.14 (s, 1 H, γ-CH), 6.50–8.04 (m, Ar) ppm; for the
second conformation: δ 0.62 (s, 1H, OH), 1.54 (s, 6 H, CMe), 1.92

776 Organometallics, Vol. 27, No. 4, 2008
Yang et al.
(w), 1804 (w), 1700 (w), 1624 (w), 1584 (w), 1549 (m), 1528 (s),
1319 (s), 1252 (s), 1202 (w), 1180 (m), 1108 (m), 1100 (m), 1018
(s), 936 (m), 890 (w), 862 (m), 834 (s), 799 (s), 757 (s), 723 (m),
682 (w), 657 (w), 638 (w), 573 (m). EI-MS: m/z (%) 550.4 (68)
[M+], 535.3 (100) [M+ - Me]. Anal. Calcd for C32H51AlN2O2Si
(550.8): C, 69.78; H, 9.33; N, 5.09. Found: C, 69.44; H, 9.17; N,
4.93.
and Cp2ZrMe2 (0.26 g, 1 mmol). Yield: 0.49 g (63%); mp 390–391
°C. 1H NMR (300.13 MHz, C6D3): δ 0.30 (s, 3 H, ZrMe), 0.64 (d,
J ) 6.6 Hz, 6 H, CH(CH3)2), 0.98 (d, J ) 6.8 Hz, 6 H, CH(CH3)2),
1.07 (d, J ) 6.8 Hz, 6 H, CH(CH3)2), 1.53 (s, 6 H, CMe),1.56 (d,
J ) 6.8 Hz, 6 H, CH(CH3)2), 3.03 (sept, J ) 6.7 Hz, 2 H,
CH(CH3)2), 3.33 (sept, J ) 6.8 Hz, 2 H, CH(CH3)2), 4.88 (s, 1 H,
γ-CH), 5.47 (s, 10 H, C5H5), 7.00–7.34 (m, Ar) ppm. 13C NMR
(125.8 MHz, C6D6): δ 171.3 (CN), 138.2 (br, i-Ph), 145.0, 143.9,
141.3 (o-, o-, i-Ar), 138.2, 128.5 (o-, p-Ph), 127.5 (p-Ar), 125.6
(m-Ph), 125.2, 124,2 (m-, m-Ar), 110.7 (C5H5), 97.8 (γ-CH), 29.2,
28.2 (CH(CH3)2), 25.0, 24.6, 24.3 (CH(CH3)2), 23.7 (ꢀ-CH3), 19.5
(ZrMe) ppm. IR (Nujol mull, cm-1): ν˜ 1875 (w), 1809 (w), 1704
(w), 1581 (w), 1543 (m), 1522 (s), 1317 (s), 1257 (s), 1196 (m),
1176 (m), 1126 (m), 1096 (m), 1080 (m), 1058 (m), 1044 (m),
1018 (s), 971 (w), 952 (w), 934 (m), 875 (s), 863 (s), 798 (s), 759
(s), 726 (s), 705 (m), 670 (m), 639 (m). EI-MS: m/z (%) 772.3 (4)
[M+], 757.4 (100) [M+ - Me]. Anal. Calcd for C46H59AlN2OZr
(774.2): C, 71.36; H, 7.68; N, 3.62. Found: C, 71.68; H, 7.45; N,
3.52. X-ray quality crystals of 17 · (n-hexane)0.5 were grown from
the solution of n-hexane.
L3AlMe(µ-O)ZrMeCp2 (14). Toluene (40 mL) was added to
the mixture of L3AlMe(OH) (8) (0.56 g, 1 mmol) and Cp2ZrMe2
(0.26 g, 1 mmol). The resulting solution was stirred for 2 h at room
temperature and then continuously for 24 h at 100 °C. After
filtration, the solution was kept at room temperature overnight to
isolate colorless crystals. Yield: 0.33 g (41%); mp >390 °C (dec).
1H NMR (500.13 MHz, C6D3): δ -0.21 (s, 3 H, AlMe), -0.04 (s,
3 H, ZrMe), 1.05 (s, 18 H, C(CH3)3), 1.26 (d, J ) 7.0 Hz, 6 H,
CH(CH3)2), 1.30 (d, J ) 6.8 Hz, 6 H, CH(CH3)2), 1.49 (d, J ) 7.0
Hz, 6 H, CH(CH3)2), 1.53 (d, J ) 7.4 Hz, 6 H, CH(CH3)2), 3.37
(sept, J ) 6.8 Hz, 2 H, CH(CH3)2), 3.59 (sept, J ) 6.4 Hz, 2 H,
CH(CH3)2), 5.43 (s, 10 H, C5H5), 5.74 (s, 1 H, γ-CH), 7.08–7.15
(m, Ar) ppm. 13C NMR (125.8 MHz, C6D6): δ 178.8 (CN), 145.6,
143.5, 143.2, 127.1, 124.6, 124.4 (o-, o-, i-, p-, m-, m-Ar), 110.7
(C5H5), 99.6 (γ-CH), 43.4 (ꢀ-C(CH3)3), 32.5 (ꢀ-C(CH3)3), 28.9,
28.4 (CH(CH3)2), 28.1, 25.9, 24.9, 24.0 (CH(CH3)2), 18.5 (ZrMe),
-10.2 (br, AlMe) ppm. IR (Nujol mull, cm-1): ν˜ 3322 (w), 1647
(w), 1620 (w), 1581 (w), 1530 (w), 1402 (w), 1315 (m), 1274 (w),
1263 (w), 1216 (w), 1191 (w), 1157 (w), 1137 (w), 1097 (w), 1058
(w), 1019 (w), 967 (w), 934 (w), 919 (w), 863 (w), 847 (w), 794
(m), 753 (w), 742 (m), 723 (w), 693 (w). EI-MS: m/z (%) 779.4
(100) [M+ - Me]. Anal. Calcd for C47H69AlN2OZr (796.3): C,
70.89; H, 8.73; N, 3.52. Found: C, 70.64; H, 8.55; N, 3.50.
L1AlEt(µ-O)ZrMeCp2 (15). Preparation of 15 was accomplished
like that of 14 from L1AlEt(OH) (9) (0.41 g, 1 mmol) and Cp2ZrMe2
(0.26 g, 1 mmol). Yield: 0.21 g (34%); mp 193–195 °C. 1H NMR
(500.13 MHz, C6D3): δ 0.19 (q, J ) 8.0 Hz, 2 H, AlCH2CH3),
0.29 (s, 3 H, ZrMe), 1.35 (t, J ) 7.8 Hz, 3 H, AlCH2CH3), 1.41 (s,
6 H, CMe), 2.11 (s, 6 H, p-ArMe), 2.26 (s, 6 H, o-ArMe), 2.27 (s,
6 H, o-ArMe), 4.78 (s, 1 H, γ-CH), 5.46 (s, 10 H, C5H5), 6.80–7.15
(m, Ar) ppm. 13C NMR (125.8 MHz, C6D6): δ 169.2 (CN), 141.2,
135.8, 134.7, 133.1, 130.1, 129.7 (i-, p-, o-, o-, m-, m-Ar), 110.3
(C5H5), 96.9 (γ-CH), 22.4 (ꢀ-CH3), 20.8 (p-ArMe), 19.5 (o-ArMe),
18.4 (o-ArMe), 19.5 (ZrMe), 9.9 (AlCH2CH3), 3.2 (br, AlCH2CH3)
ppm. IR (Nujol mull, cm-1): ν˜ 1624 (w), 1609 (w), 1538 (m), 1391
(m), 1296 (w), 1261 (w), 1249 (w), 1228 (w), 1202 (w), 1149 (w),
1095 (w), 1021 (w), 958 (w), 935 (w), 874 (w), 859 (m), 799 (m),
761 (w), 740 (w), 723 (w), 653 (w), 593 (w). EI-MS: m/z (%) 625.2
(64) [M+ - Me], 611.2 (100) [M+ - Et]. Anal. Calcd for
C36H47AlN2OZr (642.0): C, 67.35; H, 7.38; N, 4.36. Found: C,
67.24; H, 7.28; N, 4.32.
L2AlOEt(µ-O)ZrMeCp2 (18). Preparation of 18 was accom-
plished like that of 14 from L2AlOEt(OH) (12) (0.51 g, 1 mmol)
and Cp2ZrMe2 (0.26 g, 1 mmol). Yield: 0.55 g (74%); mp 377–378
°C. 1H NMR (500.13 MHz, C6D6): δ 0.04 (s, 3 H, ZrMe), 1.03 (d,
J ) 6.8 Hz, 6 H, CHMe2), 1.24 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.40
(t, 3 H, OCH2CH3), 1.45 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.51 (s, 6
H, CMe), 1.58 (d, J ) 6.6 Hz, 6 H, CHMe2), 3.10 (sept, J ) 6.8
Hz, 2 H, CHMe2), 3.52 (sept, J ) 6.8 Hz, 2 H, CHMe2), 3.97 (q,
2 H, J ) 6.8 Hz, OCH2CH3), 4.82 (s, 1 H, γ-CH), 5.50 (s, 10 H,
C5H5), 7.00–7.21 (m, Ar) ppm. 13C NMR (125.76 MHz, C6D6): δ
170.4 (CN), 144.8, 143.7, 141.4, 127.5, 124.8, 124.4 (o-, o-, i-, p-,
m-, m-Ar), 110.5 (C5H5), 97.3 (γ-CH), 58.5 (OCH2CH3)), 28.8, 27.7
(CH(CH3)2), 25.7, 24.8, 24.8, 24.5 (CH(CH3)2), 23.4 (ꢀ-CH3), 21.0
(OCH2CH3)), 18.8 (ZrMe) ppm. IR (Nujol mull, cm-1): ν˜ 1938
(w), 1872 (w), 1806 (w), 1591 (w), 1531 (m), 1318 (m), 1258 (m),
1177 (m), 1129 (w), 1100 (w), 1079 (w), 1018 (m), 936 (w), 876
(m), 853 (m), 794 (s), 761 (m), 723 (w), 666 (w), 638(w). EI-MS:
m/z (%) 725.3 (100) [M+ - Me]. Anal. Calcd for C42H59AlN2O2Zr
(742.1): C, 67.97; H, 8.01; N, 3.77. Found: C, 67.88; H, 7.94; N,
3.73.
L2AlOSiMe3(µ-O)ZrMeCp2 (19). Preparation of 19 was ac-
complished like that of 14 from L2AlOSiMe3(OH) (13) (0.55 g, 1
mmol) and Cp2ZrMe2 (0.26 g, 1 mmol). Yield: 0.51 g (65%); mp
376–377 °C. 1H NMR (500.13 MHz, C6D6): δ -0.20 (s, 3 H,
ZrMe), 0.31 (s, 9 H, SiMe3), 1.04 (d, J ) 6.8 Hz, 6 H, CHMe2),
1.27 (d, J ) 6.8 Hz, 6 H, CHMe2), 1.44 (d, J ) 6.8 Hz, 6 H,
CHMe2), 1.50 (s, 6 H, CMe), 1.52 (d, J ) 6.8 Hz, 6 H, CHMe2),
3.11 (sept, J ) 6.8 Hz, 2 H, CHMe2), 3.53 (sept, J ) 6.8 Hz, 2 H,
CHMe2), 4.95 (s, 1 H, γ-CH), 5.54 (s, 10 H, C5H5), 7.01–7.23 (m,
Ar) ppm. 13C NMR (125.76 MHz, C6D6): δ 171.3 (CN), 144.9,
143.2, 141.6, 127.3, 125.1, 124.5 (o-, o-, i-, p-, m-, m-Ar), 99.1
(γ-CH), 28.7, 27.5 (CH(CH3)2), 26.4, 25.2, 24.8, 24.6 (CH(CH3)2),
23.7 (ꢀ-CH3), 17.5 (ZrMe), 3.5 (Si(CH3)3) ppm. 29Si NMR (99.36
MHz, C6D6): δ -4.21 ppm. IR (Nujol mull, cm-1): ν˜ 1587 (w),
1552 (w), 1525 (m), 1320 (m), 1252 (m), 1179 (m), 1160 (w), 1110
(w), 1052 (s), 1019 (m), 936 (m), 913 (s), 843 (m), 832 (m), 797
(s), 776 (m), 758 (m), 744 (m), 726 (m), 693 (w), 678 (w), 649
(w), 597 (w), 556 (m). EI-MS: m/z (%) 769.3 (100) [M+ - Me].
Anal. Calcd for C43H63AlN2O2SiZr (786.3): C, 65.69; H, 8.08; N,
3.56. Found: C, 65.44; H, 7.87; N, 3.50.
L1AlPh(µ-O)ZrMeCp2 (16). Preparation of 16 was accom-
plished like that of 14 from L1AlPh(OH) (10) (0.22 g, 0.5 mmol)
and Cp2ZrMe2 (0.14 g, 0.5 mmol). Yield: 0.23 g (67%); mp
145–147 °C. 1H NMR (500.13 MHz, C6D6): δ 0.31 (s, 3 H, ZrMe),
1.45 (s, 6 H, CMe), 1.78 (s, 6 H, o-ArMe), 2.07 (s, 6 H, p-ArMe),
2.26 (s, 6 H, o-ArMe), 4.92 (s, 1 H, γ-CH), 5.48 (s, 10 H, C5H5),
6.62–7.94 (m, Ar) ppm. 13C NMR (125.76 MHz, C6D6): δ 169.9
(CN), 151.4 (br, i-Ph), 140.9 (i-Ar), 138.1 (o-Ph), 135.9, 134.4,
133.7, 130.0, 129.9 (p-, o-, o-, m-, m-Ar), 128.9, 127.4, (p-, m-Ph),
110.5 (C5H5), 97.3 (γ-CH), 22.5 (ꢀ-CH3), 20.8 (p-ArMe), 19.4 (o-
ArMe), 19.2 (o-ArMe), 18.2 (ZrMe) ppm. IR (Nujol mull, cm-1):
ν˜ 1625 (w), 1553 (w), 1528 (w), 1297 (w), 1261 (w), 1249 (w),
1225 (w), 1201 (w), 1149 (w), 1085 (w), 1019 (w), 961 (w), 890
(m), 796 (m), 746 (w), 726 (w), 704 (w), 674 (w), 570 (w), 529
(w), 508 (w), 484 (w), 449 (w). EI-MS: m/z (%) 688.3 (2) [M+],
673.2 (100) [M+ - Me]. Anal. Calcd for C40H47AlN2OZr (690.0):
C, 69.63; H, 6.87; N, 4.06. Found: C, 69.55; H, 6.70; N, 3.89.
L2AlPh(µ-O)ZrMeCp2 (17). Preparation of 17 was accom-
plished like that of 14 from L2AlPh(OH) (11) (0.54 g, 1 mmol)
X-ray Structure Determination of 10–13 and 17. The data for
all five compounds were collected from shock-cooled crystals at
100(2) K.23 The data for 11 were collected on a Bruker SMART-
APEX II diffractometer with a D8 goniometer, and the other
structures were measured on a Bruker TXS-Mo rotating anode with
(23) (a) Kottke, T.; Stalke, D. J. Appl. Crystallogr. 1993, 26, 615–619.
(b) Stalke, D. Chem. Soc. ReV. 1998, 27, 171–178.

Organoaluminum Hydroxides
Organometallics, Vol. 27, No. 4, 2008 777
APEX II detector on a D8 goniometer. Both diffractometers were
equipped with a low-temperature device. The Bruker SMART-
APEX II diffractometer used graphite-monochromated Mo KR
radiation, λ ) 0.71073 Å. The Bruker TXS-Mo rotating anode used
INCOATEC Helios mirror optics as radiation monochromator. The
data of 10-13 and 17 were integrated with SAINT,24 and an
empirical absorption (SADABS) was applied.25 The structures were
solved by direct methods (SHELXS-97)26 and refined by full-matrix
least-squares methods against F2 (SHELXL-97).27 All non-
hydrogen atoms were refined with anisotropic displacement pa-
rameters. The hydrogen atoms were refined isotropically on
calculated positions using a riding model with their Uiso values
constrained to 1.5 times the Ueq of their pivot atoms for terminal
sp3 carbon atoms and 1.2 times for all other carbon atoms. The
positions of the hydrogen atoms in the OH groups were found with
a difference Fourier analysis of the remaining electron density. The
oxygen-hydrogen bond lengths were restrained to 0.84 Å, and the
Uiso were constrained to 1.2 times the Ueq of the oxygen atoms.
Crystallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge
Crystallographic Data Centre. The CCDC numbers are listed in
Table 1. Copies of the data can be obtained free of charge from
the Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/
data_request/cif.
Polymerization of Ethylene. The polymerization reactions were
carried out on a high-vacuum line (10-5 Torr) in an autoclave
(Buchi). In a typical experiment, 100 mL of dry toluene (from Na/
K) was vacuum-transferred into the polymerization flask and
saturated with 1.0 atm of rigorously purified ethylene. The catalyst
(22.2 µmol) was taken in the Schlenk flask and appropriate MAO
(1.6 M in toluene, Witco GmbH) was added. The mixture was
stirred for 20 min to activate the catalyst. The catalyst solution
was then quickly injected into the rapidly stirred flask using a
gastight syringe. After a measured time interval, the polymerization
was quenched by the addition of methanol (5 mL) and the reaction
mixture was then poured into methanol (800 mL). The polymer
was allowed to fully precipitate overnight and then collected by
filtration, washed with fresh methanol, and dried.
Acknowledgment. This work was supported by the
Deutsche Forschungsgemeinschaft, the Fonds der Chemi-
schen Industrie, and the Göttinger Akademie der Wissen-
schaften. Y.Y. thanks the Chinese Scholarship Council for
a fellowship.
(24) SAINT-NT: Bruker AXS Inc.: Madison, WI, 2000.
(25) Sheldrick, G. M. SADABS 2.0; Universität Göttingen: Göttingen,
Germany, 2000.
(26) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467–473.
(27) Sheldrick, G. M. SHELX-97: Program for the Solution and
Refinement of Crystal Structures; Universität Göttingen: Göttingen, Ger-
many, 1997.
Supporting Information Available: Crystallographic data for
10-13 and 17 as a CIF file. This material is available free of charge
via the Internet at http://pubs.acs.org.
OM700969G