Preparation of molecular alumoxane hydrides, hydroxides, and hydrogensulfides

Article abstract of DOI:10.1002/anie.200605081

Suppressed aggregation: The unprecedented alumoxane hydrogensulfide [{LAI(SH)}²(μ-O)] and the unique sulfide-bridged compound [{LAI(SH)}₂(μ-S)] can be prepared from the easily accessible aluminum dihydride [LAIH₂] (L = HC-

Full text of DOI:10.1002/anie.200605081

Angewandte
Chemie
DOI: 10.1002/anie.200605081
Alumoxanes
Preparation of Molecular Alumoxane Hydrides, Hydroxides, and
Hydrogensulfides**
Sandra Gonzµlez-Gallardo, Vojtech Jancik, Raymundo Cea-Olivares, RubØn A. Toscano, and
Mónica Moya-Cabrera*
Research on the controlled hydrolysis of aluminum com-
pounds has led to the isolation and structural characterization
of several interesting alumoxanes.[1] Alumoxanes (entities
containing Al-O-Al moieties) are known to easily undergo
association, leading to oligomeric structures.[1a,b] Thus, the
preparation of molecular alumoxanes with low degrees of
association in a pure, crystalline form remains a synthetic
challenge. Moreover, organically modified alumoxanes are
not common,[1c,d] although they are highly desirable com-
pounds owing to their potential application as cocatalysts in
the polymerization of a wide range of organic monomers.[2]
Aluminum hydride compounds have been demonstrated to
be useful precursors for the preparation of organoalumox-
anes[3] and aluminum chalcogenides.[4] Indeed, the aluminum
ature to afford [{LAl(H)}2(m-O)] (2) in 90% yield (Scheme 1).
À
The IR spectrum of 2 shows the Al H valence vibration at
1799 cmÀ1, while the mass spectrum exhibits the highest peak
hydride [iPrLAlH2] (iPrL = HC[(CMe)N(2,6-iPr2C6H3)]2
)
À
[4a]
bearing the sterically encumbered b-diketiminate ligand iPrL
is easily transformed into the aluminum hydrogensulfide
[
iPrLAl(SH)2] upon reaction with elemental sulfur in the
presence of a catalytic amount of P(NMe2)3.[4b] However, the
preparation of the alumoxane hydroxide [{iPrLAl(OH)}2(m-
O)] requires an ammonia/toluene two-phase liquid system
with [iPrLAlI2] as the starting material.[5a]
Scheme 1. Formation of compounds 2–4; Ar=2,4,6-Me3C6H2.
at [M+ÀH], indicating the formation of the alumoxane
hydride. The thermal stability of 2 and its unique structural
arrangement make it an advantageous starting material for
the preparation of alumoxanes containing aluminum atoms
with terminal SH groups.
Compound 2 reacts cleanly in toluene with two equiv-
alents of elemental sulfur to yield the first known alumoxane
bearing two terminal SH groups, [{LAl(SH)}2(m-O)] (3; 85%
yield). Furthermore, 2 reacts smoothly in toluene with two
equivalents of water to produce the alumoxane hydroxide
[{LAl(OH)}2(m-O)] (4; 82%). Compound 4 can also be
obtained by the direct reaction of 1 with three equivalents
of water at ambient temperature (73%).
Compounds 2–4 are stable over a long period of time
when stored under an inert atmosphere and are highly soluble
in common organic solvents (benzene, toluene, CH2Cl2, THF)
but insoluble in hexane and pentane. The facile hydrolysis of
1, yielding alumoxanes 2 and 4, contrasts significantly with the
reaction conditions required for the preparation of the
analogous[{iPrLAl(OH)}2(m-O)].[5]
Treatment of 1 with 1.5 equivalents of elemental sulfur in
toluene at ambient temperature gives [{LAl(SH)}2(m-S)] (5)
in 75% yield (Scheme 2). No evidence was found to suggest
the formation of the aluminum hydrogensulfide [LAl(SH)2].
Moreover, the presence of P(NMe2)3 is not required for the
formation of the terminal SH groups in 3 and 5. However, the
addition of a catalytic amount of P(NMe2)3 at ambient
temperature substantially decreases the yield of 5 (36%),
During our research with the sterically modified alumi-
num hydride [LAlH2] (L = HC[(CMe)N(2,4,6-Me3C6H2)]2 ),
À
we observed that this compound readily reacts with water,
forming Al-O-Al moieties under very mild conditions.
Herein, we describe the preparation of the unprecedented
alumoxane hydride [{LAl(H)}2(m-O)] (2) and hydrogensulfide
[{LAl(SH)}2(m-O)] (3), as well as the unique [{LAl(SH)}2(m-
S)] (5) from the readily available aluminum hydride [LAlH2]
(1). To the best of our knowledge, 3 represents the first
example of a structurally characterized alumoxane bearing
terminal SH groups.
Reaction of LH in toluene with AlH3·NMe3 at room
temperature yields 1 in 94% yield. Compound 1 reacts
smoothly with one equivalent of water at ambient temper-
[*] S. Gonzµlez-Gallardo, Dr. V. Jancik, Prof. Dr. R. Cea-Olivares,
Dr. R. A. Toscano, Dr. M. Moya-Cabrera
Instituto de Química
Universidad Nacional Autónoma de MØxico
Circuito Exterior
Ciudad Universitaria, MØxico 04510 (Mexico)
Fax: (+52)55-5616-2217
E-mail: monica.moya@correo.unam.mx
[**] We thank the UNAM (PAPIIT grant 209706) for financial support
and T. Flores for technical assistance. V.J. acknowledges the UNAM
for his postdoctoral fellowship.
Supporting information for this article is available on the WWW
under http://www.angewandte.org or from the author.
Angew. Chem. Int. Ed. 2007, 46, 2895 –2898
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
2895

Communications
O)] (1808; 3,5-Me2py = 3,5-dimethylpyridine)[5b]
and for [{(tBu)2Al[NH(Me)CH2CH2NMe2]}2(m-
O)](1808).[5c] The Al (m-O) distances in
3
À
(1.687 Š) are only slightly longer than those in 4
(1.691, 1.701 Š), which are comparable to those in
[{iPrLAl(OH)}2(m-O)] (1.698, 1.694 Š), but shorter
than that reported for [(m-O){iPrLAl(m-O)}2-
(AlMe)] (av 1.715 Š).[5a] The Al-S-Al angle in 5
Scheme 2. Formation of 5 and its hydrolysis to 3; Ar=2,4,6-Me3C6H2.
giving insoluble [LAl(m-S)2AlL] as the only by-product.
Compound 5 is air- and moisture-sensitive and reacts readily
with one equivalent of water with subsequent elimination of
H2S to produce 3.
Colorless single crystals of 1 (see the Supporting Infor-
mation), 3 (Figure 1), 4 (Figure 2), and 5 (Figure 3) were
grown from their saturated toluene solutions at À328C within
several days.[6] Compound 3 crystallizes in the monoclinic
Figure 2. Molecular structure of 4; hydrogen atoms except OH are
omitted for clarity. Thermal ellipsoids are set at 50% probability.
Selected bond lengths [Š] and angles [8]: Al(1)-O(1) 1.707(2), Al(1)-
O(2) 1.691(2), Al(2)-O(2) 1.701(2), Al(2)-O(3) 1.710(2), Al(1)-N(1)
1.900(2), Al(1)-N(2) 1.889(2), Al(2)-N(3) 1.890(2), Al(2)-N(4) 1.896(2);
Al(1)-O(2)-Al(2) 136.8(1), O(1)-Al(1)-O(2) 118.0(1), O(2)-Al(1)-O(3)
117.6(1), N(1)-Al(1)-N(2) 95.4(1), N(3)-Al(1)-N(4) 95.2(1).
Figure 1. Molecular structure of 3; hydrogen atoms (except SH) and
solvent atoms are omitted for clarity. Thermal ellipsoids are set at
50% probability. Selected bond lengths [Š] and angles [8]: Al(1)-O(1)
1.687(1), Al(1)-S(1) 2.231(1), Al(1)-N(1) 1.895(3), Al(1)-N(2) 1.894(3),
S(1)-H(1) 1.21(1); Al(1)-O(1)-Al(1A) 155.2(2), O(1)-Al(1)-S(1)
111.0(1), N(1)-Al(1)-N(2) 96.6(1), Al(1)-S(1)-H(1) 95(3).
space group I2/a with one half of the molecule of 3 and one
molecule of toluene in the asymmetric unit, whereas com-
pound 4 crystallizes in the monoclinic space group P21/n as a
nonmerohedral twin with one molecule of 4 in the asymmetric
unit. Compound 5 crystallizes in the orthorhombic space
group Pna21 with one molecule in the asymmetric unit.
Unfortunately, we were not able to crystallize pure 5, thus
data for 5 which contains about 25% of 4 were used.
In all three compounds (3–5), the aluminum center
possesses a distorted tetrahedral geometry and is coordinated
to two nitrogen atoms from the b-diketiminato ligand. The
remaining two coordination sites are occupied by sulfur and
oxygen atoms (3), two oxygen atoms (4), or two sulfur atoms
(5). The Al-O-Al angle in 3 (155.28), is more obtuse than that
in 4 (136.88) and those found in [{iPrLAl(OH)}2(m-O)] (112.38)
and [(m-O){iPrLAl(m-O)}2(AlMe)] (125.78),[5a] but significantly
smaller than those reported for [{(tBu)2Al(3,5-Me2py)}2(m-
Figure 3. Molecular structure of 5; hydrogen atoms except SH are
omitted for clarity. Thermal ellipsoids are set at 50% probability.
Selected bond lengths [Š] and angles [8]: Al(1)-S(1) 2.150(3), Al(1)-S(2)
2.206(2), Al(2)-S(1) 2.163(3), Al(2)-S(3) 2.214(2), Al(1)-S(1)-Al(2)
110.8(1); S1(1)-Al(1)-S(2) 120.7(1), S(1)-Al(2)-S(3) 119.5(1), N(1)-
Al(1)-N(2) 96.9(2), N(3)-Al(1)-N(4) 96.4(2).
2896 www.angewandte.org
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Angewandte
Chemie
C6D6, 258C): d = À1.47 (s, 2H, AlSH), 1.46 (s, 12H, CH3), 2.06–2.15
(110.88) is less obtuse than the Al-O-Al angles in compounds
(s, 24H, o-ArCH3), 2.35 (s, 12H, p-ArCH3), 4.92 (s, 2H, g-CH), 6.76–
6.83 ppm (m, 8H, m-ArH); 13C NMR (75.6 MHz, C6D6, 258C): d =
19.4 (CH3), 20.7 (p-ArCH3), 22.5 (o-ArCH3), 96.9 (g-CH), 129.3,
À
3 and 4, most probably because of the longer Al (m-S)
distances (2.150, 2.163 Š) and the resulting larger separation
À
between the organic ligands. The Al S(H) bond length in 3
=
134.0, 135.1, 140.7 (i-, o-, m-, p-C(Ar)), 169.3 ppm (C N); IR (CsI):
À
(2.231 Š) is larger than the terminal Al S(H) bond lengths in
n˜ = 2561 cmÀ1 (w, AlS H); EI-MS (70 eV): m/z (%): 802 (20)
À
[M+ÀH]. Elemental analysis (%) calcd for C46H60Al2N4OS2
À
5 (2.206, 2.214 Š). The above-mentioned Al (m-S) distances
for 4 are shorter than those reported for [iPrLAl(m-S)2AliPrL]
(803.09): C 68.8, H 7.5, N 7.0; found: C 69.1, H 7.7, N 6.9.
(2.237, 2.245 Š),[7a]
and
[
iPrLAl(m-S3)2AliPrL] (2.223, 2.248 Š),[7b]
4: A solution of H2O (1.0m, 2.8 mL, 2.8 mmol) in THF was slowly
added to a solution of 2 (2.10 g, 2.8 mmol) in toluene (30 mL) at room
temperature. The reaction mixture was stirred for 12 h and filtered.
All volatiles were removed under vacuum to leave a white residue,
which was treated with hexane (10 mL). After filtration and drying
under vacuum, 4 was obtained as a white powder. Yield: 1.77 g
(82%); m.p. 1608C (decomp); 1H NMR (300 MHz, C6D6, 258C): d =
À0.64 (s, 2H, AlOH), 1.43 (s, 12H, CH3), 1.89 (s, 12H, p-ArCH3), 2.22
(s, 12H, o-ArCH3), 2.45 (s, 12H, o-ArCH3), 4.82 (s, 2H, g-CH), 6.81–
6.85 ppm (m, 8H, m-ArH); 13C NMR (75.6 MHz, C6D6, 258C): d =
18.8 (CH3), 20.8 (p-ArCH3), 22.0 (o-ArCH3), 95.8 (g-CH), 127.8,
LAl(m-S)(m-C(SiMe3) C C(SiMe3)S)AliPrL] (2.230,
= =
[
iPr
2.219 Š).[7c] In all three compounds, the XH groups (X = O,
S) from the HX1-Al1-X2-Al2-X3H moiety are in a cis
1
1
2
2
À
À
conformation with an angle between the X Al X and X -
Al2-X3 planes of 588 (3), 728 (4), and 508 (5).
The facile synthesis of 2 allows access to the preparation
of unprecedented molecular alumoxanes bearing two differ-
ent Group 16 atoms covalently bonded to the same aluminum
center, as well as to the modified alumoxane hydroxide
[{LAl(OH)}2(m-O)], on a large scale. Furthermore, the cis
conformation of the terminal SH and OH groups makes these
compounds ideal precursors for further synthesis of hetero-
metallic compounds. The preparation of such multimetallic
systems is the subject of ongoing research.
=
129.1, 134.5, 141.3 (i-, o-, m-, p-C(Ar)), 168.4 ppm (C N); IR (CsI):
n˜ = 3650 cmÀ1 (m, AlO H); EI-MS (70 eV): m/z (%): 770 (100)
À
[M+ÀH]. Elemental analysis (%) calcd for C46H60Al2N4O3 (770.96):
C 71.7, H 7.8, N 7.3; found: C 71.2, H 7.6, N 7.0.
5: Compound 1 (3.00 g, 8.29 mmol) and elemental sulfur (0.66 g,
20.7 mmol) were dissolved in toluene (30 mL) at ambient temper-
ature. The reaction mixture was stirred for 4 h and filtered. All
volatiles were removed under vacuum, leaving a white residue, which
was treated with hexane (10 mL). After filtration and drying under
vacuum, 5 was obtained as a white powder. Yield: 2.48 g (75%);
m.p. 1888C (decomp); 1H NMR (300 MHz, C6D6, 258C): d = À0.81 (s,
2H, AlSH), 1.42 (s, 12H, CH3), 2.07 (s, 12H, p-ArCH3), 2.36 (s, 24H,
o-ArCH3), 4.86 (s, 2H, g-CH), 6.76 ppm (m, 8H, m-ArH); 13C NMR
(75.6 MHz, C6D6, 258C): d = 18.7 (CH3), 20.6 (p-ArCH3), 22.6 (o-
Experimental Section
All manipulations were performed under a dry and oxygen-free
atmosphere (N2) by using Schlenk-line and glovebox techniques.
1: A solution of AlH3·NMe3 (1.0m, 70 mL, 70 mmol) in toluene
was slowly added to a solution of LH (20.00 g, 60 mmol) in toluene
(50 mL). The reaction mixture was stirred for 24 h, after which any
insoluble material was filtered off and the volatiles were removed
under vacuum. An oily residue remained, which solidified upon
treatment with cold hexane (40 mL). After filtration and drying under
vacuum, 1 was obtained as a white powder. Yield: 20.40 g (94%);
ArCH3), 97.7 (g-CH), 129.9, 133.6, 135.9, 139.0 (i-, o-, m-, p-C(Ar)),
À1
=
À
170.8 ppm (C N); IR (CsI): n˜ = 2559 cm (m, AlS H); EI-MS
(70 eV): m/z (%): 819 (13) [M+]. Elemental analysis (%) calcd for
C46H60Al2N4S3 (819.15): C 67.4, H 7.4, N 6.8; found: C 66.9, H 7.1,
N 6.7.
1
m.p. 2008C (decomp); H NMR (300 MHz, C6D6, 258C): d = 1.47 (s,
6H, CH3), 2.09 (s, 6H, p-ArCH3), 2.32 (s, 12H, o-ArCH3), 4.79 (s, 1H,
g-CH), 6.74 ppm (m, 4H, m-ArH); 13C NMR (75.6 MHz, C6D6,
258C): d = 18.2 (CH3), 20.6 (p-ArCH3), 21.8 (o-ArCH3), 95.5 (g-CH),
Received: December 15, 2006
Published online: March 20, 2007
=
129.7, 133.3, 135.6, 139.5 (i-, o-, m-, p-C(Ar)), 169.4 ppm (C N); IR
Keywords: aluminum · alumoxanes · hydrides ·
hydrogensulfides · hydrolysis
(CsI): n˜ = 1815, 1775 cmÀ1 (s, AlH2); EI-MS (70 eV): m/z (%): 361
(100) [M+ÀH]. Elemental analysis (%) calcd for C23H31AlN2 (362.49):
C 76.2, H 8.6, N 7.7; found: C 75.9, H 8.6, N 7.5.
.
2: A solution of H2O (1.0m, 6.9 mL, 6.9 mmol) in THF was slowly
added to a solution of 1 (5.00 g, 13.8 mmol) in toluene (30 mL) at
room temperature. The reaction mixture was stirred for 12 h and
filtered. All volatiles were removed under vacuum to leave a viscous
white residue, which was treated with hexane (10 mL). After filtration
and drying under vacuum, 2 was obtained as a white powder. Yield:
4.59 g (90%); m.p. 2158C (decomp); 1H NMR (300 MHz, C6D6,
258C): d = 1.56 (s, 12H, CH3), 2.09 (s, 12H, p-ArCH3), 2.24–2.27 (s,
24H, o-ArCH3), 3.99 (br, 2H, AlH), 4.95 (s, 2H, g-CH), 6.72–
6.76 ppm (m, 8H, m-ArH); 13C NMR (75.6 MHz, C6D6, 258C): d =
18.8 (CH3), 20.7 (p-ArCH3), 22.2 (o-ArCH3), 95.9 (g-CH), 129.4,
[1] a) S. Pasynkiewicz, Polyhedron 1990, 9, 429 – 453, and references
therein; b) M. R. Mason, J. M. Smith, S. G. Bott, A. R. Barron, J.
Am. Chem. Soc. 1993, 115, 4971 – 4984; c) C. J. Harlan, M. R.
Mason, A. R. Barron, Organometallics 1994, 13, 2957 – 2969;
d) H. W. Roesky, M. G. Walawalkar, R. Murugavel, Acc. Chem.
Res. 2001, 34, 201 – 211, and references therein; e) J. Lewinski, W.
Bury, I. Justyniak, J. Lipkowski, Angew. Chem. 2006, 118, 2938 –
2941; Angew. Chem. Int. Ed. 2006, 45, 2872 – 2875; f) L. B.
Jerzykiewicz, J. Utko, P. Sobota, Organometallics 2006, 25,
4924 – 4926; g) C. C. Landry, C. J. Harlan, S. G. Bott, A. R.
Barron, Angew. Chem. 1995, 107, 1315 – 1317; Angew. Chem.
Int. Ed. Engl. 1995, 34, 1201 – 1202.
[2] a) H. Sinn, W. Kaminsky, Adv. Organomet. Chem. 1980, 18, 99 –
149; b) T. L. Feng, P. L. Gurian, M. D. Healy, A. R. Barron, Inorg.
Chem. 1990, 29, 408 – 411; c) C. J. Harlan, M. R. Mason, A. R.
Barron, Organometallics 1994, 13, 2957 – 2969; d) Y. Koide, S. G.
Bott, A. R. Barron, Organometallics 1996, 15, 2213 – 2226; e) M.
Galimberti, M. Destro, O. Fusco, F. Piemontesi, I. Camurati,
Macromolecules 1999, 32, 258 – 263; f) W. Kaminsky, Catal. Today
2000, 62, 23 – 34; g) M. Watanabi, C. N. McMahon, C. J. Harlan,
A. R. Barron, Organometallics 2001, 20, 460 – 467.
=
132.8, 134.7, 140.9 (i-, o-, m-, p-C(Ar)), 168.1 ppm (C N); IR (CsI):
n˜ = 1799 cmÀ1 (m, AlH); EI-MS (70 eV): m/z (%): 738 (100) [M+ÀH].
Elemental analysis (%) calcd for C46H60Al2N4O (738.96): C 74.8,
H 8.2, N 7.6; found: C 74.0, H 8.1, N 7.5.
3: Compound 2 (2.77 g, 3.75 mmol) and elemental sulfur (0.30 g,
9.38 mmol) were dissolved in toluene (30 mL) at ambient temper-
ature. The reaction mixture was stirred for 5 h and filtered to remove
the insoluble material. All volatiles were evaporated under vacuum to
leave a white residue, which was washed with hexane (10 mL). After
filtration and drying under vacuum, 3 was obtained as a white powder.
Yield: 2.56 g (85%); m.p. 1508C (decomp); 1H NMR (300 MHz,
Angew. Chem. Int. Ed. 2007, 46, 2895 –2898
ꢀ 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org 2897

Communications
[3] a) W. Zheng, N. C. Mosch-Zanetti, H. W. Roesky, M. Noltemeyer,
wR2 = 0.1028 for all data. The final difference Fourier synthesis
À3
M. Hewitt, H.-G. Schmidt, T. R. Schneider, Angew. Chem. 2000,
112, 4446 – 4449; Angew. Chem. Int. Ed. 2000, 39, 4276 – 4279;
b) Y. Peng, G. Bai, H. Fan, D. Vidovic, H. W. Roesky, J. Magull,
Inorg. Chem. 2004, 43, 1217 – 1219; c) R. J. Wehmschulte, P. P.
Power, J. Am. Chem. Soc. 1997, 119, 8387 – 8388.
gave a min/max residual electron density of À0.302/ + 0.283 eŠ
.
d) Crystal data for 5: C46H60Al2N4O0.25S2.75 (815.10), orthorhom-
bic, space group Pna21, a = 20.794(3), b = 9.525(2), c =
23.442(4) Š, V= 4643(1) Š3, Z = 4, 1calcd = 1.166 gcmÀ3, F(000) =
1744, l = 0.71073 Š, T= 173(2) K, m(MoKa) = 0.222 mmÀ1. Flack
parameter was refined to 0.05(12). Of the 13896 measured
reflections, 6121 were independent (Rint = 0.0740). The final
refinements converged at R1 = 0.0614 for I > 2s(I), wR2 = 0.1299
for all data. The final difference Fourier synthesis gave a min/max
residual electron density of À0.212/ + 0.276 eŠÀ3. Data for the
structures of 1 and 3–5 were measured on a Bruker-APEX three-
circle diffractometer. Intensity measurements were performed on
rapidly cooled crystals (0.50 ” 0.20 ” 0.17 mm3) in the range
3.348 ꢀ 2q ꢀ 50.728 (1), (0.34 ” 0.21 ” 0.18 mm3) in the range
2.828 ꢀ 2q ꢀ 50.188 (3), (0.18 ” 0.12 ” 0.12 mm3) in the range
2.948 ꢀ 2q ꢀ 50.868 (4), and (0.27 ” 0.25 ” 0.09 mm3) in the range
3.488 ꢀ q ꢀ 50.088 (5). The structures were solved by direct
methods (SHELXS-97)[8] and refined against all data by full-
matrix least squares on F2.[9] The hydrogen atoms from the OH
and SH groups were localized from the difference electron-
density map and refined isotropically. The twin law for 4 was
determined as a 1808 rotation around the real axis [101]. CCDC-
630404–630407 contain the supplementary crystallographic data
for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif.
[4] a) C. Cui, H. Roesky, H. Hao, H.-G. Schmidt, M. Noltemeyer,
Angew. Chem. 2000, 112, 1885 – 1887; Angew. Chem. Int. Ed. 2000,
39, 1815 – 1817; b) V. Jancik, Y. Peng, H. W. Roesky, J. Li, D.
Neculai, A. M. Neculai, R. Herbst-Irmer, J. Am. Chem. Soc. 2003,
125, 1452 – 1453.
[5] a) G. Bai, H. W. Roesky, J. Li, M. Noltemeyer, H.-G. Schmidt,
Angew. Chem. 2003, 115, 5660 – 5664; Angew. Chem. Int. Ed.
2003, 42, 5502 – 5506; b) L. G. van Poppel, S. G. Bott, A. R.
Barron, J. Chem. Crystallogr. 2001, 31, 417 – 420; c) C. N. McMa-
hon, A. R. Barron, J. Chem. Soc. Dalton Trans. 1998, 3703 – 3704.
[6] a) Crystal data for 1: C23H31AlN2 (362.48), monoclinic, space
group P21/n, a = 7.377(2), b = 24.346(4), c = 12.303(3) Š, b =
96.09(3)8, V= 2197(1) Š3, Z = 4, 1calcd = 1.096 gcmÀ3, F(000) =
784, l = 0.71073 Š, T= 294(2) K, m(MoKa) = 0.101 mmÀ1. Of the
18099 measured reflections, 3999 were independent (Rint
=
0.0314). The final refinements converged at R1 = 0.0462 for I >
2s(I), wR2 = 0.1331 for all data. The final difference Fourier
synthesis gave a min/max residual electron density of À0.203/
+ 0.223 eŠÀ3. b) Crystal data for 3·toluene: C60H76Al2N4OS2
(987.33), monoclinic, space group I2/a, a = 22.857(5), b =
8.707(2), c = 28.967(5) Š, b = 96.22(3)8, V= 5731(2) Š3, Z = 4,
1calcd = 1.144 gcmÀ3, F(000) = 2120, l = 0.71073 Š, T= 173(2) K,
m(MoKa) = 0.165 mmÀ1. Of the 14094 measured reflections, 5046
were independent (Rint = 0.0730). The final refinements con-
verged at R1 = 0.0599 for I > 2s(I), wR2 = 0.1650 for all data. The
[7] a) V. Jancik, M. M. Moya-Cabrera, H. W. Roesky, R. Herbst-
Irmer, D. Neculai, A. M. Neculai, M. Noltemeyer, H.-G. Schmidt,
Eur. J. Inorg. Chem. 2004, 3508 – 3512; b) Y. Peng, H. Fan, V.
Jancik, H. W. Roesky, R. Herbst-Irmer, Angew. Chem. 2004, 116,
6316 – 6318; Angew. Chem. Int. Ed. 2004, 43, 6190 – 6192; c) H.
Zhu, J. Chai, Q. Ma, V. Jancik, H. W. Roesky, H. Fan, R. Herbst-
Irmer, J. Am. Chem. Soc. 2004, 126, 10194 – 10195.
[8] SHELXS-97, Program for Structure Solution: G. M. Sheldrick,
Acta Crystallogr., Sect. A 1990, 46, 467 – 473.
[9] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure
Refinement, Universitꢀt Gꢁttingen, Gꢁttingen, 1997.
final difference Fourier synthesis gave
a min/max residual
electron density of À0.214/ + 0.389 eŠÀ3. c) Crystal data for 4:
C46H60Al2N4O3 (770.94), monoclinic, space group P21/n, a =
11.248(3), b = 21.112(4), c = 18.346(3) Š, b = 93.23(3)8, V=
4350(2) Š3, Z = 4, 1calcd = 1.177 gcmÀ3
,
F(000) = 1656, l =
0.71073 Š, T= 173(2) K, m(MoKa) = 0.110 mmÀ1. Of the 7990
measured reflections, 7990 were independent (Rint = 0.0478).
The final refinements converged at R1 = 0.0528 for I > 2s(I),
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Angew. Chem. Int. Ed. 2007, 46, 2895 –2898