Oxidative addition of σ Bonds to an Al(I) center

Article abstract of DOI:10.1021/ja5038337

The Al(I) compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]^- and Ar = 2,6-Prⁱ₂C₆H₃) reacts with H-X (X = H, Si, B, Al, C, N, P, O) σ bonds of H₂, silanes, borane (HBpin, pin = pinacolate), allane (NacNacAlH₂), phosphine (HPPh₂), amines, alcohol (PrⁱOH), and Cp H (Cp* = pentamethylcyclopentadiene) to give a series of hydride derivatives of the four-coordinate aluminum NacNacAlH(X), which are characterized herein by spectroscopic methods (NMR and IR) and X-ray diffraction. This method allows for the syntheses of the first boryl hydride of aluminum and novel silyl hydride and phosphido hydride derivatives. In the case of the addition of NacNacAlH ₂, the reaction is reversible, proving the possibility of reductive elimination from the species NacNacAlH(X).

Full text of DOI:10.1021/ja5038337

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Article
Oxidative addition of # bonds to an Al(I) center
Terry Chu, Ilia Korobkov, and Georgii I. Nikonov
J. Am. Chem. Soc., Just Accepted Manuscript • DOI: 10.1021/ja5038337 • Publication Date (Web): 03 Jun 2014
Downloaded from http://pubs.acs.org on June 4, 2014
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Oxidative addition of σ bonds to an Al(I) center
Terry Chu,† Ilia Korobkov,‡ Georgii I. Nikonov*,†
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†Department of Chemistry, Brock University, 500 Glenridge Ave, St. Catharines, ON L2S 3A1, Canada
‡XꢀRay Core Facility, Faculty of Science, University of Ottawa, 150 Louis Pasteur, Ottawa, ON K1N 6N5, Canada
ABSTRACT: The Al(I) compound NacNacAl (1, NacNac = [ArNC(Me)CHC(Me)NAr]− and Ar = 2,6ꢀPri2C6H3) reacts with HꢀX
(X = H, Si, B, Al, C, N, P, O) σ bonds of H2, silanes, borane (HBpin, pin=pinacolate), allane (NacNacAlH2), phosphine (HPPh2),
amines, alcohol (PriOH), and Cp*H (Cp*= pentamethylcyclopentadiene) to give a series of hydride derivatives of the 4ꢀcoordinate
aluminum NacNacAlH(X) which were characterized by spectroscopic methods (NMR and IR) and Xꢀray diffraction. This method
allows for the syntheses of the first boryl hydride of aluminum and novel silyl hydride and phosphido hydride derivatives. In the
case of the addition of NacNacAlH2 the reaction is reversible, proving the possibility of reductive elimination from the species
NacNacAlH(X).
Introduction
Mainꢀgroup metal catalysis is of great current interest due
can be classified as an aromatically stabilised carbenoid,
featuring an Alꢀbased lone pair and an accessible antibonding
π*(AlꢀN) orbital. Such a situation, i.e. the presence of a metalꢀ
centered lone pair and an accessible vacant orbital, is
reminiscent of transition metal centers amenable for activation
of robust bonds.1 This fact prompted our study of oxidative
addition reactions to this Al(I) center (Scheme 1). Indeed,
molecular hydrogen cleanly adds to complex 1 at 70 ºC to
furnish the known dihydride compound NacNacAlH2 (2).26
Encouraged by this result and given the analogy between HꢀH
and SiꢀH bond activation,3 we studied the addition of silanes to
1. H3SiPh readily adds to 1 at room temperature after stirring
overnight to give the silyl hydride NacNacAlH(SiH2Ph) (3),
whereas heating overnight at 70 ºC was required for the
bulkier silane H2SiMePh to produce NacNacAlH(SiHMePh)
(4). Compounds 3 and 4 represent rare examples of silyl
hydride derivatives of Al(III), with only one other example
to its potential to circumvent the high cost and toxicity of
common transition metal catalysts.1,2 However, its further
development faces several obstacles, of which the lack of
activation of robust sigma bonds is one of the biggest
problems. The success of transition metal catalysis relates in
great extent to the ease of activation of HꢀH, HꢀSi, HꢀB, HꢀC
etc. bonds, which proceeds either by the formation of σꢀ
complexes, e.g. Mꢀ(σꢀHꢀX),3 or more commonly by oxidative
addition, e.g. MH(X).4 Addition of HꢀX bonds to mainꢀgroup
centers are much less common.1,5 Examples include the
hydrogenations of digermyne,6 borole,7 digalene (GaR)2,8
NacNacGa (NacNac = [ArNC(Me)CHC(Me)NAr]− and Ar =
2,6ꢀPri2C6H3)9 and carbenes,10,11 as well as heterolytic splitting
of H2 by Frustrated Lewis Pairs, i.e. a pair of a Lewis acid and
base that cannot form an adduct for steric reasons,12ꢀ16 which
finds many applications in catalytic hydrogenation.12,17 The Hꢀ
Si bond undergoes a similar heterolytic cleavage by a
combination Lewis acids and bases,18 allowing for ionic
hydrosilylation of organic substrates.19 Addition of BꢀH, CꢀH,
SiꢀH, NꢀH, and PꢀH bonds to a single mainꢀgroup element
center has been observed for a few Group 14 carbenoids10,11,20
and for a P(III) center supported by an ONO tridentate
ligand.21 Oxidative additions to a single Group 13 center has
been studied for atomic reactions with H2 and NH3 in frozen
matrixes,22 whereas activation of the HꢀH bond has been
demonstrated by Ga(I) aryls, via a 2+2 addition to the
digallene RGa=GaR.8 Most relevant to this study is the report
by Linti et al. on HꢀX bond addition to a low valent gallium(I)
complex, NacNacGa,9 and addition of aryl and alkyl halides to
NacNacIn.23 Here we report the first examples of oxidative
additions of a series of robust sigma HꢀX bonds (X=H, B, C,
Si, N, P, O) to a single Al(I) center supported by the
diiminoacetylacetonate ligand.
being
LSiH(AlH2(NMe3))
(5,
L
=
(ArN)C(=CH2)CH=C(Me)(NAr)) reported by Driess et al.27
1
The SiꢀH bonds in 3 and 4 give rise to the H NMR signals at
3
3
3.87 (d, JHꢀH = 2.8 Hz) and 4.20 ppm (dq, JHꢀH =5.1 Hz, 3JHꢀ
= 6.6 Hz), respectively, which correlates with the upfield
H(Al)
29Si NMR resonances at −74.0 and −48.0 ppm. The AlꢀH
1
signals cannot be observed directly by H NMR spectroscopy
because of quadrupolar broadening on the 27Al center (nuclear
spin = 5/2), but the presence of the AlꢀH bond is confirmed by
the IR stretches observed at 1785 cmꢀ1 both for 3 and 4. The
Xꢀray structure of 4 is shown in Figure 1. The NacNac
Results and Discussion
The Al(I) compound NacNacAl (1) was reported over a
decade ago24 and its reactivity towards unsaturated molecules
has been extensively studied by Roesky et al.25 Compound 1
Scheme 1. Oxidative additions to the Al(I) compound 1
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fragment is nearly planar (mean deviation of 0.029 Å), with
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the Al atom sitting above the N1ꢀC4ꢀC3ꢀC2ꢀN2 plane by
0.751 Å. The Al(1)ꢀSi(1) bond distance of 2.4551(8) Å is
comparable with the corresponding distance in 5, 2.487(1) Å,27
and the average AlꢀSi distance on a 4ꢀcoordinate Al center
(2.466 Å).28 The AlꢀN distances of 1.9043(15) and 1.9084(15)
Å are shorter than in the parent NacNac complex 1 having a 2ꢀ
coordinate aluminum (1.957(2) Å),24 but comparable with the
related compound NacNacAl(η2(F,B)ꢀB(C6F5)3) (6) with a 4ꢀ
coordinate aluminum (1.885(4) and 1.900(3) Å).29 Another
prominent feature of 4 and its analogues discussed below is
the significant distortion of the N2AlHX (X = Si, B, C, P, etc.)
fragment from tetrahedral geometry in that the NꢀAlꢀN bond
angle is significantly smaller than the NꢀAlꢀX angle (in 4:
95.66(7)° vs. 111.94(5)° and 115.08(5)° for X = Si).
Scheme 2. Examples of boryl aluminum compounds. Ar =
2,6-Pri2C6H3
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Figure 2. Molecular structure of 7 (thermal ellipsoids are shown
at 50%, hydrogen atoms except the hydride are omitted for
clarity). The oxygen atoms are disordered but only one pair is
shown for clarity. Selected bonds (Å) and angles (°): Al(1)ꢀN(1)
1.9095(11), Al(1)ꢀN(2) 1.9103(11), Al(1)ꢀB(1) 2.1232(15), N(1)ꢀ
Al(1)ꢀN(2) 95.12(5), N(1)ꢀAl(1)–B(1) 119.18(6), N(2)ꢀAl(1)ꢀB(1)
110.65(5).
Figure 1. Molecular structure of 4 (thermal ellipsoids are shown
at 50%, hydrogen atoms except the hydride are omitted for clariꢀ
ty). Selected bonds (Å) and angles (°): Al(1)ꢀSi(1) 2.4551(8),
Al(1)ꢀN(1) 1.9043(15), Al(1)ꢀN(2) 1.9084(15), N(1)ꢀAl(1)ꢀN(2)
95.66(7), N(1)ꢀAl(1)ꢀSi(1) 111.94(5), N(2)ꢀAl(1)ꢀSi(1) 115.08(5).
Related oxidative addition of the AlꢀH bond of 2 to 1
results in the formation of an equilibrium mixture of the
starting compounds and the dimer (NacNacAl(H)ꢀ)2 (10,
Scheme 3). At room temperature complex 10 forms in about
Given the diagonal analogy between silicon and boron,
we then studied the reactions of boranes with 1. HBpin (pin =
pinacolate) adds to 1 at room temperature in the course of 3
hours to furnish cleanly the first boryl hydride derivative of
aluminum, NacNacAlH(Bpin) (7, Scheme 2). Complex 7 was
characterized by multinuclear NMR spectroscopy, IR
spectroscopy, and Xꢀray analysis. Similar to complex 3 and 4,
1H NMR data are indicative of Cs symmetry in solution.30 The
boryl ligand gives rise to the 11B NMR resonance at 34.9 ppm,
consistent with a 3ꢀcoordinate boron, and the presence of the
AlꢀH bond is evidenced by the observation of an IR stretch at
1795 cmꢀ1. The chemistry of boron substituted compounds of
aluminum is mainly represented by carborane and borohydride
derivatives. The first boryl substituted aluminum compounds,
(THF)Me2AlꢀB(NArCHꢀ)2 and ((µꢀMe)MeAlꢀB(NArCHꢀ)2)2
(8 and 9, Scheme 2), have been obtained only recently by
Anwander et al.31 by reacting AlMe3 with Yamashita’s
borylide [Li(THF)2][B(NArCHꢀ)2]. The molecular structure of
7 (Figure 2) closely resembles that of 4. The AlꢀB single bond
of 2.1232(15) Å in 7 is comparable with the corresponding
distances in 8 (2.150(2) Å) and 9 (2.119(3) Å). There are also
a few structurally characterised Lewis adducts between
nucleophilic Al(I) species32 and electrophilic boranes which
feature donorꢀacceptor Al→B bonds in the range of 2.115(2) –
2.183(5) Å, with the longest value found in the 4ꢀcoordinate
1
50% yield. The H NMR spectrum of 10 displays four septets
for the methine protons and eight doublets for the methyls of
the Pri groups on the aryl rings, consistent with the effective
C2 or Ci symmetry in solution. IR spectrum of the mixture
displays new bands at 1778 and 1772 cmꢀ1 attributed to the Alꢀ
H bond and similar to the AlꢀH stretches at 1832 and 1795 cmꢀ
1
observed for 2.26, Upon heating the reaction mixture to 50
34
°C, complex 10 disproportionates back to a mixture of the
starting compounds 1 and 2, indicating an entropy driven
reaction. However, returning to room temperature results in
clean reproduction of the original equilibrium mixture without
any side reactions. The equilibrium between 1, 2, and 10 was
studied by 1H NMR spectroscopy and the thermodynamic
parameters (ꢁH = −42.0 ± 0.7 kJ mol−1; ꢁS = −130.8 ± 2.0 J
K−1 mol−1) were extracted from the van’t Hoff plot in the range
from 295 to 348 K (Figure 3). This dynamic process is of
interest as a proof of principle of reductive elimination from
an aluminum center. Reductive elimination of HꢀX bonds is a
key step in many transition metal catalysed reactions but is
uncommon for main group complexes. Previously Beachley
and coꢀworkers reported the synthesis of organometallic
Ga(I)35 and In(I)36 compounds via elimination of SiMe4 from
KM(CH2SiMe3)3H (M = Ga or In). However, the results were
not reproducible and the proposed decomposition likely
follows a more complicated pathway rather than a simple
Al complex 6.29,
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reductive elimination.37 More recently, Fischer et al. has
reported the reductive elimination of Cp*H from Cp*AlH2 to
furnish the Al(I) compound Cp*Al, with the three species
being in equilibrium in toluene at 110 °C.38
versus the range found for other NacNacAlH(X) species
1
2
3
discussed herein (1.9043(15) – 1.9095(11) Å), which can be
accounted for by the significant steric strain imposed by the
bulky Ar and Cp* groups.
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Scheme 3. Equilibrium between 1 and 2 to give 10
2
1
0
-1
-2
0.0028
0.003
0.0032
0.0034
0.0036
1/T
Figure 4. Molecular structure of 11 (thermal ellipsoids are shown
at 50%, hydrogen atoms except the hydride are omitted for clariꢀ
ty). Selected bonds (Å) and angles (°): Al(1)ꢀN(1) 1.9534(11),
Al(1)ꢀC(1) 2.0901(19), N(1)ꢀC(8) 1.3387(17), N(1)ꢀAl(1)ꢀN(1a)
93.64(7), N(1)ꢀAl(1)ꢀC(1) 117.78(5), C(4)ꢀC(1)ꢀAl(1) 118.50(14),
C(2)ꢀC(1)ꢀAl(1) 97.07(10).
Figure 3. van’t Hoff plot of the equilibrium between 1, 2, and 10
(R2 = 0.999).
Complex 1 does not react with the sp2 CꢀH bonds of
benzene, toluene or terminal alkene and neither with the sp Cꢀ
H bonds of alkynes. In the latter two cases, addition to the πꢀ
system takes place.25 Similar πꢀcomplexation occurs for the Cꢀ
Amines add readily to the Al(I) precursor 1 at room
temperature. Thus, the addition of H2NBut is completed after
stirring for 3 days, whereas the more acidic aniline H2NPh
requires only 16 hours. The formation of amido hydride
products 12 and 13, respectively, was established by
multinuclear NMR and IR spectroscopy, Xꢀray studies, and by
comparison with the related compound NacNacAlH(NHAr)
(14) obtained by the reaction of NacNacAlH2 with H2NAr.40 In
particular, the presence of AlꢀH bonds in 12 and 13 is
evidenced from the IR stretches at 1812 and 1854 cmꢀ1,
respectively. Both compounds show two sets of signals in the
1H NMR spectrum for the methine CHs of the Pri groups on
the aryl rings consistent with Cs symmetry. The NꢀH signals
were observed as broad signals at −0.03 and 3.27 ppm for 12
and 13, respectively. The molecular structure of compound 12
is shown in Figure 5. The structure of 13 is very similar and is
given in the supporting information.30 The molecule of 12 is
bisected by a crystallographically imposed symmetry plane
running through atoms Al(1), N(2) and C(2). The But group on
the amido center N(2) is rotationally disordered. The NꢀH and
AlꢀH protons are in transoid arrangement, which results in the
alignment of the amide lone pair in parallel with the N(1)ꢀ
N(1a) vector and hence leads to the possibility of partial
electron transfer on the antibonding orbitals of the Al(1)ꢀN(1)
and Al(1)ꢀN(1a) bonds. Although the short Al(1)ꢀN(2)
distance of 1.7859(19) Å (cf. with the average AlꢀN distance
on a 4ꢀcoordinate aluminum of 1.927 Å) appear to support this
notion, the Al(1)ꢀN(1) distance, 1.9069(1) Å, is quite normal.
H
acidic cyclopentadiene. However, for the sterically
encumbered pentamethylcyclopentadiene, oxidative addition
of the CꢀH bond takes place at 70 °C in the course of 3 days to
give the hydride alkyl derivative NacNacAlH(Cp*) (11, Cp*=
C5Me5). Compound 11 was characterised by multinuclear
NMR and IR spectroscopy and its structure was confirmed by
Xꢀray crystallography. In particular, two types of Pri groups are
1
3
observed by H NMR spectroscopy at 3.57 (hept, JHꢀH = 6.8
3
Hz) and 3.16 ppm (hept, JHꢀH = 6.9 Hz), consistent with Cs
symmetry. The methyl groups of the Cp* ligand gives rise to a
singlet at 1.48 ppm indicating the occurrence of a fast haptoꢀ
tropic shift. Like the other aluminum hydrides discussed
above, the AlꢀH signal is not observed by 1H NMR
spectroscopy but the presence of the AlꢀH bond is supported
by the IR stretch at 1802 cmꢀ1. The molecular structure of 11 is
shown in Figure 4. The molecule lies on a special position,
with a crystallographically imposed symmetry plane running
through atoms C(7), Al(1), C(1), and C(4). The Al(1) center is
attached to the C(1) atom of the Cp* ligand with a distance of
2.0901(19) Å, which is 0.109 Å longer than the average AlꢀC
distance in 4ꢀcoordinate hydrido alkyl aluminum compounds
(1.981 Å).39 Such an elongated AlꢀC bond and the acute C(2)ꢀ
C(1)ꢀAl(1) bond angle of 97.07(10)° indicate that bonding of
Al(1) to the Cp* ring has a significant pꢀcharacter on carbon,
which is consistent with the facile haptotropic shift of the Cp*
ligand observed by 1H NMR. Unlike the related structures of 4
and 7, the NacNac ligand is slightly folded, with the dihedral
angle between the N(1)ꢀC(8)ꢀC(7) and N(1a)ꢀC(8a)ꢀC(7)
planes being 13.3°. Another telling feature is the very
significant elongation of the Al(1)ꢀN(1) bond (1.9534(11) Å)
Related addition of a less polar but weaker PꢀH bond of
HPPh2 also occurs at room temperature and affords a
phosphide hydride derivative of aluminum, NacNacAlH(PPh2)
(15). The 1H and 13C NMR features for 15 are similar to those
of other NacNacAlH(X) complexes reported above. The
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Figure 5. Molecular structure of 12 (thermal ellipsoids are shown
Figure 6. Molecular structure of 15 (thermal ellipsoids are shown
at 50%, hydrogen atoms except the hydride are omitted for clariꢀ
ty). Selected bonds (Å) and angles (°): Al(1)ꢀN(1) 1.9069(11),
Al(1)ꢀN(2) 1.7859(19), N(1)ꢀC(1) 1.3324(15), N(2)ꢀC(16)
1.450(3), N(1)ꢀAl(1)ꢀN(1a) 94.63(6), N(2) Al(1)ꢀN(1) 112.00(5).
at 50%, hydrogen atoms are omitted for clarity).Selected bonds
(Å) and angles (°): Al(1)ꢀP(1) 2.3971(6), Al(1)ꢀN(1) 1.8963(13),
Al(1)ꢀN(2) 1.9070(13), N(1)ꢀAl(1)ꢀN(2) 95.42(6), N(1)ꢀAl(1)ꢀ
P(1) 112.02(4), N(2)ꢀAl(1)ꢀP(1) 111.55(4).
presence of the phosphide ligand is supported by the upfield
31P NMR signal at −67.9 ppm. The hydride gives rise to the
AlꢀH stretch at 1778 cmꢀ1 in the IR spectrum. The molecular
structure of 15 found by Xꢀray diffraction is shown in Figure
6. The AlꢀP distance of 2.3971(6) Å is comparable to the
average AlꢀP bond found on neutral 4ꢀcoordinate aluminum
hydrido phosphides (2.375 Å)41 and 4ꢀcoordinate phosphide
hydride aluminates (2.403 Å).42 Given the small size of the
hydride ligand, it appears that the AlꢀP bond length is
primarily controlled by steric factors. The phosphide center is
pyramidal, with the sum of bond angles equal to 308.72(7)°.
Finally, the reaction of complex 1 with HOPri occurs
smoothly at room temperature in the course of 16 hours to
furnish the hydrido alkoxy product NacNacAlH(OPri) (16).
Compound 16 was characterised by spectroscopic data and Xꢀ
ray analysis.30 Although many hydrido alkoxides of 4ꢀ
coordinate aluminum are known, most of them are aluminate
compounds with bulky aryloxide ligands.43 Therefore,
compound 16 represents a rare example of a neutral,
monomeric hydrido alkoxy species. The structural features of
16 are very close to those of the related hydrido amides 12 and
13. The AlꢀO bond distance of 1.6969(15) Å is shorter than
the average AlꢀO distance in neutral, monomeric 4ꢀcoordinate
hydrido aryloxy aluminum compounds (1.723 Å),44 but
comparable with the AlꢀO distance in monomeric 4ꢀcoordinate
aryloxide hydride aluminates (1.712 Å)45 and 3ꢀcoordinate Al
compounds.46 Thus, like the related amide derivatives we can
conclude that this metric is primarily determined by the steric
hindrance around the aluminum center.
Experimental Section
Unless stated otherwise, all manipulations were
performed using standard inert atmosphere (N2 gas) gloveꢀbox
and Schlenk techniques. Benzene, toluene, and hexanes were
dried using a Grubbsꢀtype solvent purification system. C6D6
was dried by distillation from K/Na alloy. NMR spectra were
obtained with a Bruker DPXꢀ300 and DPXꢀ600 instruments
(1H, 300 MHz and 600 MHz; 13C, 75 MHz and 151 MHz; 11B,
96 MHz and 193 MHz; 29Si, 60 MHz and 119 MHz; 31P, 121
MHz and 243 MHz) at room temperature, unless specified
otherwise. IR spectra were measured on a PerkinꢀElmer 1600
FTꢀIR spectrometer. Elemental analysis was performed by the
ANALEST laboratories (University of Toronto) or the
analytical laboratory of McMaster University. Analyses were
done in quadruplicate, but were generally found to be low in
carbon, regardless if a single crystal or a well ground powder
was
submitted.
Methylphenylsilane
(MePhSiH2),
pinacolborane (HBPin), tertꢀbutylamine (H2NBut), aniline
(H2NPh), and isopropanol (PriOH) were purchased from
SigmaꢀAldrich. Pentamethylcyclopentadiene (Cp*H) was
purchased from Strem Chemicals. Phenylsilane (PhSiH3) and
diphenylphosphine (Ph2PH) were prepared by the reduction of
PhSiCl3 and Ph2PCl with LiAlH4, respectively. Compound 1
was prepared according to a literature procedure.24
Reaction of 1 with hydrogen. An NMR tube was charged
with 1 (0.007 g, 0.016 mmol) dissolved in 0.6 mL of C6D6.
Hydrogen gas (4 atm) was introduced into the sample and
heated at 70 °C overnight to cleanly furnish 2. The
spectroscopic data are consistent with previously published
data.26
Conclusion
In conclusion, we found that the Al(I) compound
NacNacAl shows transition metalꢀlike reactivity towards the
oxidative addition of robust HꢀX bonds leading to a series of
aluminum hydrides NacNacAlH(X) substituted by silyl, boryl,
aluminyl, alkyl, amido, phopshido, and alkoxy groups.
Investigations into the application of these species towards
catalytic processes are in progress and will be reported in due
course.
NacNacAlH(SiH2Ph) (3). A solution of 1 (0.118 g, 0.265
mmol) in benzene (6 mL) was added to a flask followed by the
addition of PhSiH3 (0.033 mL, 0.265 mmol). The reaction was
stirred overnight at room temperature to yield a dark yellow
solution. Volatiles were removed under vacuo and taken up in
hexanes. Colourless crystals of 3 were obtained upon cooling
1
to ꢀ30 °C (0.092 g, 0.166 mmol, 63%). H NMR (600 MHz,
C6D6): δ 7.13 (m, 2H, C6H5), 7.08 (m, 2H, C6H5), 6.96 (m, 7H,
C6H3 and C6H5), 4.93 (s, 1H, CH), 3.87 (d, 2H, SiH2Ph, 3JHꢀH
=
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Journal of the American Chemical Society
2.8 Hz), 3.42 (hept, 2H, CH(CH3)2, 3JHꢀH = 6.9 Hz), 3.35 (hept,
was allowed to stand for 4 hours at room temperature and the
2H, CH(CH3)2, 3JHꢀH = 6.9 Hz), 1.54 (s, 6H, NCCH3), 1.43 (d,
resulting solution contained a mixture of 1, 2, and 10. 1H
NMR (600 MHz, C6D6): 7.17 (m, 8H, C6H3) 7.01 (t, 2H, mꢀH
Ar, 3JHꢀH = 7.6 Hz), 6.85 (d, 2H, pꢀH Ar, 3JHꢀH = 7.7 Hz), 4.69
(s, 2H, CH), 3.77 (hept, 2H, CH(CH3)2, 3JHꢀH = 6.1 Hz), 3.67
1
2
3
4
5
6
7
8
6H, CH(CH3)2, 3JHꢀH = 6.8 Hz), 1.17 (d, 6H, CH(CH3)2, 3JHꢀH
=
3
6.7 Hz), 1.13 (d, 6H, CH(CH3)2, JHꢀH = 6.9 Hz), 1.11 (d, 6H,
CH(CH3)2, 3JHꢀH = 6.8 Hz). 13C{1H} NMR (151 MHz, C6D6): δ
171.0 (NCCH3), 145.6, 143.0, 134.7, 128.3, 127.7, 127.5,
127.4, 125.2, 124.4 (C6H3 and C6H5), 140.5 (Cipso), 136.3 (oꢀC
Ph), 97.8 (CH), 29.4, 28.2 (CH(CH3)2), 26.2, 24.8, 24.3, 24.2
(CH(CH3)2), 23.0 (NCCH3). 29Si INEPT+ NMR (119 MHz,
C6D6, J = 200 Hz): δ −74.3 (m, SiH2Ph). IR (nujol): ν = 2065
cmꢀ1 (SiꢀH), 1785 cm−1 (AlꢀH). Anal Calcd for C35H49AlN2Si:
C, 76.04; H, 8.93; N, 5.07. Found: C, 74.71; H, 9.10; N, 5.01.
3
(hept, 2H, CH(CH3)2, JHꢀH = 6.9 Hz), 3.53 (hept, 2H,
CH(CH3)2, 3JHꢀH = 6.9 Hz), 2.95 (sp, 2H, CH(CH3)2, 3JHꢀH = 6.6
3
Hz), 1.74 (d, 6H, CH(CH3)2, JHꢀH = 6.8 Hz), 1.50 (m, 12H,
NCCH3 and CH(CH3)2), 1.31 (s, 6H, NCCH3), 1.21 (d, 6H,
CH(CH3)2, 3JHꢀH = 6.9 Hz), 1.12 (d, 6H, CH(CH3)2, 3JHꢀH = 6.8
9
3
Hz), 1.09 (d, 6H, CH(CH3)2, JHꢀH = 7.0 Hz), 0.90 (d, 6H,
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
CH(CH3)2, 3JHꢀH = 6.6 Hz), 0.84 (d, 6H, CH(CH3)2, 3JHꢀH = 6.6
Hz). 13C{1H} NMR (151 MHz, C6D6): δ 169.8, 168.4
(NCCH3), 145.8, 145.6, 144.5, 143.8, 143.0, 142.1, 127.7,
127.4, 127.0, 126.9, 125.5, 125.1, 124.4, 124.0 (C6H3), 98.1
(CH), 29.9, 28.4, 28.1, 27.7 (CH(CH3)2), 28.8, 26.0, 25.6,
25.3, 25.1, 25.1, 24.9 (CH(CH3)2), 24.4, 23.4 (NCCH3). IR
(nujol): ν = 1778, 1772 cm−1 (AlꢀH).
NacNacAlH(SiHMePh) (4). A flask containing 1 (0.120 g,
0.270 mmol) in benzene (8 mL) was charged with MePhSiH2
(0.037 mL, 0.270 mmol) and heated with stirring for 16 hours
at 70 °C. Solvent was removed from the resulting yellow
solution and the residue was dissolved in a 1:2 mixture of
toluene and hexanes. Cooling the solution to −30 °C afforded
1
NacNacAlH(Cp*) (11). Cp*H (0.043 mL, 0.277 mmol) was
added to a flask containing 1 (0.123 g, 0.277 mmol) in
benzene (8 ml). The mixture was heated with stirring at 70 °C
for 3 days to give a pale orange solution. Removal of the
solvent in vacuo yielded a yellow solid. The product was
recrystallized in a 1:2 mixture of toluene and hexanes at −30
°C to give yellow crystals of 11 (0.099 g, 0.170 mmol, 61%).
1H NMR (300 MHz, C6D6): δ 7.15 (m, 6H, C6H3), 4.90 (s, 1H,
colourless crystals of 4 (0.107 g, 0.189 mmol, 70%). H NMR
(300 MHz, C6D6): 7.05 (m, 9H, C6H3, mꢀH Ph and pꢀH Ph),
6.90 (m, 2H, oꢀH Ph), 4.93 (s, 1H, CH), 4.20 (dq, 1H,
SiH(CH3)Ph, 3JH(Si)ꢀH(C) = 5.1 Hz, 3JH(Si)ꢀH(Al) = 6.6 Hz), 3.46 (m,
3
3H, CH(CH3)2,), 3.23 (hept, 1H, CH(CH3)2, JHꢀH = 6.9 Hz),
1.56 (s, 3H, NCCH3), 1.53 (s, 3H, NCCH3), 1.52 (d, 3H,
CH(CH3)2, 3JHꢀH = 6.8 Hz), 1.44 (d, 3H, CH(CH3)2, 3JHꢀH = 6.8
3
Hz), 1.39 (d, 3H, CH(CH3)2, JHꢀH = 6.7 Hz), 1.16 (d, 3H,
CH(CH3)2, 3JHꢀH = 6.9 Hz), 1.13 (d, 6H, CH(CH3)2, 3JHꢀH = 6.8
CH), 3.57 (hept, 2H, CH(CH3)2, JHꢀH = 6.8 Hz), 3.16 (hept,
3
3
3
Hz), 1.09 (d, 3H, CH(CH3)2, JHꢀH = 6.9 Hz), 0.82 (d, 3H,
2H, CH(CH3)2, JHꢀH = 6.9 Hz), 1.48 (s, 15H, C5(CH3)5), 1.44
CH(CH3)2, 3JHꢀH = 6.7 Hz), −0.14 (d, 3H, SiH(CH3)Ph, 3JHꢀH
=
(m, 18H, NCCH3 and CH(CH3)2), 1.15 (d, 6H, CH(CH3)2, 3JHꢀH
5.1 Hz). 13C{1H} NMR (75 MHz, C6D6): δ 170.9, 170.6
(NCCH3), 145.6, 143.1, 142.8, 127.6, 127.5, 127.3, 127.1,
125.4, 125.2, 124.4 (C6H3 and C6H5), 140.9, 140.9 (Cipso),
140.1 (Cipso Ph), 134.9 (oꢀC Ph), 97.6 (CH), 29.5, 29.3, 28.2,
28.0 (CH(CH3)2), 26.4, 25.5, 24.8, 24.8, 24.4, 24.2, 24.1
(CH(CH3)2), 23.1, 22.9 (NCCH3), −7.3 (SiH(CH3)Ph). 29Si
INEPT+ NMR (119 MHz, C6D6, J = 200 Hz): δ −47.2 (m,
SiH(CH3)Ph). IR (nujol): ν = 2065 cmꢀ1 (SiꢀH), 1785 cm−1 (Alꢀ
H). Anal Calcd for C36H51AlN2Si: C, 76.28; H, 9.07; N, 4.94.
Found: C, 75.64; H, 9.31; N, 4.84.
= 6.8 Hz), 1.03 (d, 12H, CH(CH3)2, JHꢀH = 6.7 Hz). 13C{1H}
3
NMR (75 MHz, C6D6): δ 170.3 (NCCH3), 145.7, 142.8, 127.5,
125.7, 123.9 (C6H3), 144.0 (Cipso), 121.5 (C5(CH3)5), 98.0
(CH), 29.9, 28.3 (CH(CH3)2), 25.4, 24.9, 24.5, 24.3
(CH(CH3)2), 23.5 (NCCH3), 12.3 (C5(CH3)5). IR (nujol): ν =
1802 cm−1 (AlꢀH). Anal Calcd for C39H57AlN2: C, 80.64; H,
9.89; N, 4.82. Found: C, 82.39; H, 10.33; N, 4.93.
NacNacAlH(NHBut) (12). To a dark red solution of 1 (0.120
g, 0.270 mmol) in benzene (6 mL) was added H2NBut (0.028
mL, 0.270 mmol) at room temperature. The mixture was
stirred for 3 days to afford a dark yellow solution. Solvent was
removed and the solid was dissolved in hexanes which
afforded colourless crystals of 12 upon cooling to −30 °C
(0.070 g, 0.135 mmol, 50%). 1H NMR (300 MHz, C6D6): δ
NacNacAlH(BPin) (7). To a dark red solution of 1 (0.119 g,
0.268 mmol) in benzene (5 mL) was added HBPin (0.039 mL,
0.268 mmol) at room temperature. The mixture was stirred for
3 hours to afford a yellow solution. Solvent was removed to
give a pale yellow solid. Colourless crystals of 7 were
obtained upon cooling a hexanes solution to ꢀ30 °C (0.080 g,
0.152 mmol, 57%). 1H NMR (300 MHz, C6D6): δ 7.13 (m, 6H,
C6H3), 5.00 (s, 1H, CH), 3.50 (m, 4H, CH(CH3)2), 1.59 (s, 6H,
NCCH3), 1.53 (d, 6H, CH(CH3)2, 3JHꢀH = 6.8 Hz), 1.43 (d, 6H,
7.12 (m, 6H, C6H3), 4.86 (s, 1H, CH), 3.46 (hept, 2H,
3
CH(CH3)2, JHꢀH = 6.8 Hz), 3.31 (hept, 2H, CH(CH3)2, 3JHꢀH
=
6.9 Hz), 1.57 (s, 6H, NCCH3), 1.45 (m, 12H, CH(CH3)2), 1.15
(d, 6H, CH(CH3)2, 3JHꢀH = 6.9 Hz), 1.11 (d, 6H, CH(CH3)2, 3JHꢀ
= 6.8 Hz), 0.90 (s, 9H, NHꢀC(CH3)3), −0.03 (s, 1H, NHꢀ
H
3
3
C(CH3)3). 13C{1H} NMR (75 MHz, C6D6): δ 169.7 (NCCH3),
144.9, 143.6, 127.1, 124.8, 123.9 (C6H3), 140.8 (Cipso), 96.3
(CH), 48.6 (NHꢀC(CH3)3), 35.5 (NHꢀC(CH3)3), 28.9, 28.3
(CH(CH3)2), 25.8, 24.9, 24.8, 24.3 (CH(CH3)2), 23.3
(NCCH3). IR (nujol): ν = 1812 cm−1 (AlꢀH). Anal Calcd for
C33H52AlN3: C, 76.55; H, 10.12; N, 8.12. Found: C, 71.94; H,
9.87; N, 8.54.
CH(CH3)2, JHꢀH = 6.7 Hz), 1.19 (d, 12H, CH(CH3)2, JHꢀH
=
6.7 Hz), 0.73 (s, 12H, OC(CH3)2). 13C{1H} NMR (75 MHz,
C6D6): δ 170.3 (NCCH3), 145.7, 143.5, 126.8, 124.5, 123.9
(C6H3), 141.4 (Cipso), 97.7 (CH), 81.2 (OC(CH3)2), 29.1, 28.2
(CH(CH3)2), 26.7, 24.8, 24.4, 24.2 (CH(CH3)2), 25.1
(OC(CH3)2), 23.1 (NCCH3). 11B NMR (96 MHz, C6D6): δ 34.9
(br s, BꢀPin). IR (nujol): ν = 1795 cm−1 (AlꢀH). Anal Calcd for
C35H54AlBN2O2: C, 73.41; H, 9.51; N, 4.89. Found: C, 72.70;
H, 9.77; N, 4.88.
NacNacAlH(NHPh) (13). H2NPh (0.025 mL, 0.270 mmol)
was added to a flask containing 1 (0.120 g, 0.270 mmol) in
benzene (6 ml). The mixture was stirred for 16 hours at room
temperature to give a yellow solution. Removal of the solvent
in vacuo yielded a pale yellow solid. The product was
Generation of (NacNacAlH-)2 (10). A solution of 1 (0.012 g,
0.027 mmol) in C6D6 (0.6 ml) was added to 2 (0.012 g, 0.027
mmol) and the mixture charged into an NMR tube. The tube
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Journal of the American Chemical Society
Page 6 of 10
detector. The data collection results for compounds 3, 4, 7, 11,
recrystallized in hexanes at −30 °C to give colourless crystals
of 13 (0.095 g, 0.177 mmol, 66%). 1H NMR (300 MHz,
C6D6): δ 7.12 (m, 8H, C6H3 and oꢀH Ph), 6.68 (t, 1H, pꢀH Ph,
1
2
3
4
5
6
7
8
12, 13, 15 and 16 represent the best data sets obtained in
several trials for each sample. Raw data collection and
processing were performed with APEX II software package
from BRUKER AXS.47 Diffraction data for crystals of 3, 11,
3
3JHꢀH = 7.3 Hz), 6.38 (br d, 2H, mꢀH Ph, JHꢀH = 7.0 Hz) 5.07
3
(s, 1H, CH), 3.36 (hept, 2H, CH(CH3)2, JHꢀH = 6.9 Hz), 3.27
3
(s, 1H, NHꢀPh), 3.17 (hept, 2H, CH(CH3)2, JHꢀH = 6.7 Hz),
12, 15 and 16 were collected with a sequence of 0.5°
at 0, 120, and 240° in . Due to a lower symmetry and in order
to ensure adequate data redundancy, the diffraction data for 4,
7 and 13 were collected with a sequence of 0.3° scans at 0,
90, 180 and 270° in . Initial unit cell parameters were
determined from 60 data frames with 0.3° scan each
ω scans
3
1.56 (s, 6H, NCCH3), 1.44 (d, 6H, CH(CH3)2, JHꢀH = 6.8 Hz),
ϕ
3
1.14 (d, 6H, CH(CH3)2, JHꢀH = 6.8 Hz), 1.03 (d, 6H,
CH(CH3)2, 3JHꢀH = 6.8 Hz), 0.96 (d, 6H, CH(CH3)2, 3JHꢀH = 6.6
Hz). 13C{1H} NMR (75 MHz, C6D6): δ 170.5 (NCCH3),
152.1, 146.4, 143.7, 125.0, 124.4 (C6H3), 140.0 (Cipso), 128.8
(oꢀC Ph), 117.8 (mꢀC Ph), 115.4 (pꢀC Ph), 97.5 (CH), 29.1,
27.8 (CH(CH3)2), 25.1, 24.9, 24.8, 24.4 (CH(CH3)2), 23.4
(NCCH3). IR (nujol): ν = 1854 cm−1 (AlꢀH). Anal Calcd for
C35H48AlN3: C, 78.17; H, 9.00; N, 7.81. Found: C, 77.74; H,
8.72; N, 7.63.
ω
ϕ
9
ω
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
collected at the different sections of the Ewald sphere. Semiꢀ
empirical absorption corrections based on equivalent
reflections were applied.48 Unitꢀcell parameters and diffraction
ꢀ
peaks intensities were consistent with triclinic P1 (№2)
symmetry space group for compounds 4, 7 and 13. Presence of
systematic absences in the diffraction dataꢀset together with
unit cell parameters suggested the following symmetry space
groups for the remaining compounds: monoclinic P21/c (№14)
for compound 15; monoclinic P21/n (№14, alternative
settings) for compound 3 and 16; monoclinic P21/m (№11) for
compound 12, and orthorhombic Ibam (№72) for compound
11. Solutions in the centrosymmetric space groups for all
NacNacAlH(PPh2) (15). A solution of 1 (0.120 g, 0.270
mmol) in benzene (6 mL) was added to a flask followed by the
addition of Ph2PH (0.047 mL, 0.270 mmol). The reaction was
stirred for 24 hours at room temperature to yield a yellow
solution. Volatiles were removed under vacuo to afford a
yellow solid. Yellow crystals of 15 were obtained upon
cooling a toluene solution layered with hexanes to −30 °C
1
compounds
yielded
chemically
reasonable
and
(0.133 g, 0.211 mmol, 78%). H NMR (300 MHz, C6D6): δ
computationally stable results of refinement. The structures
were solved by direct methods, completed with difference
Fourier synthesis, and refined with fullꢀmatrix leastꢀsquares
procedures based on F2. For all structures the positions
hydrogen atoms attached to nonꢀcarbon atoms (Al, N, or Si)
were found as residual electron density peaks from the Fourier
maps. The hydrogen atoms directly attached to carbon atoms
were restrained to riding models and were consecutively
treated as idealized contributions during the refinement.
During the course of refinement of structure 3 a strong
residual peak was observed in the vicinity of the Alꢀbound
hydride which was successfully modeled as a hydroxyl
impurity (occupancy factor of 25%). We believe that this
impurity stems from partial hydrolysis by adventitious water
during crystallization. All scattering factors are contained in
several versions of the SHELXTL program library, with the
latest version used being v.6.12.49 Crystal and structure
refinement data are given in Tables 1, except for compound 16
whose parameters are given in the Supporting Information.
Molecular structure of compounds 3, 13, and 16 are given in
Figure SI24, Figure SI25 and Figure SI26, respectively. Other
structures are presented in the main text.
6.91 (m, 16H, C6H3 and C6H5), 4.92 (s, 1H, CH), 3.69 (hept,
2H, CH(CH3)2, 3JHꢀH = 6.9 Hz), 3.21 (hept, 2H, CH(CH3)2, 3JHꢀ
3
= 6.8 Hz), 1.64 (d, 6H, CH(CH3)2, JHꢀH = 6.8 Hz), 1.51 (s,
H
6H, NCCH3), 1.12 (d, 6H, CH(CH3)2, 3JHꢀH = 6.9 Hz), 1.08 (d,
6H, CH(CH3)2, 3JHꢀH = 6.8 Hz), 1.00 (d, 6H, CH(CH3)2, 3JHꢀH
=
6.7 Hz). 13C{1H} NMR (75 MHz, C6D6): δ 171.0 (NCCH3),
144.9, 143.5, 139.5, 139.2, 136.0, 135.7, 127.9, 127.8, 125.6,
125.4, 124.6 (C6H3 and C6H5), 140.8 (Cipso), 97.6 (CH), 29.6,
28.2 (CH(CH3)2), 25.0, 24.7, 24.2, 24.1 (CH(CH3)2), 23.3
(NCCH3). 31P{1H} NMR (121 MHz, C6D6): δ −67.85 (s, Pꢀ
Ph2). IR (nujol): ν = 1778 cm−1 (AlꢀH). Anal Calcd for
C41H52AlN2P: C, 78.06; H, 8.31; N, 4.44. Found: C, 77.38; H,
8.42; N, 4.42.
NacNacAl(H)OPri (16). A flask containing 1 (0.120 g, 0.270
mmol) in benzene (6 mL) was charged with PriOH (0.020 mL,
0.270 mmol) and stirred for 16 hours at room temperature.
Solvent was removed from the resulting yellow solution and
the residue was dissolved hexanes. Cooling the solution to ꢀ30
°C afforded colourless crystals of 16 (0.070 g, 0.139 mmol,
1
51%). H NMR (300 MHz, C6D6): δ 7.11 (m, 6H, C6H3), 4.87
3
(s, 1H, CH), 3.90 (hept, 1H, OꢀCH(CH3)2, JHꢀH = 6.1 Hz),
3.40 (m, 4H, CH(CH3)2), 1.57 (s, 6H, NCCH3), 1.52 (d, 6H,
CH(CH3)2, 3JHꢀH = 6.8 Hz), 1.41 (d, 6H, CH(CH3)2, 3JHꢀH = 6.7
Hz), 1.15 (m, 12H, CH(CH3)2), 0.72 (d, 6H, OꢀCH(CH3)2, 3JHꢀ
ASSOCIATED CONTENT
= 6.0 Hz). 13C{1H} NMR (75 MHz, C6D6): δ 170.0
H
Supporting Information. Further characterization data, molecuꢀ
lar structures of 3, 13, and 16. This material is available
free of charge via the Internet at http://pubs.acs.org.
(NCCH3), 144.8, 144.4, 127.3, 124.5, 124.3 (C6H3), 139.6
(Cipso), 96.2 (CH), 64.0 (OꢀCH(CH3)2), 28.8, 28.3 (CH(CH3)2),
27.6 (OꢀCH(CH3)2) 26.0, 24.7, 24.7, 24.5 (CH(CH3)2), 23.0
(NCCH3). IR (nujol): ν = 1824 cm−1 (AlꢀH). Anal Calcd for
C32H49AlN2O: C, 76.15; H, 9.79; N, 5.55. Found: C, 76.37; H,
10.18; N, 5.60.
AUTHOR INFORMATION
Corresponding Author
X-ray Crystallography. The crystals were mounted on thin
glass fibers using paraffin oil. Prior to data collection crystals
were cooled to 200 °K. Data were collected on a Bruker AXS
SMART single crystal diffractometer equipped with a sealed
Mo tube source (wavelength 0.71073 Å) APEX II CCD
*gnikonov@brocku.ca
Author Contributions
The manuscript was written through contributions of all authors.
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Journal of the American Chemical Society
ACKNOWLEDGMENT
G.I.N. thanks the Petroleum Research Fund for support and
CFI/OIT for an equipment grant.
1
2
3
4
5
6
7
8
9
Table 1. Crystal and structure refinement data
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
3
4
7
11
12
13
15
Empirical
formula
C35H49AlN2O0 C18H25.5Al0.5
N
C35H54AlBN2
O2
C80H100Al2N2
C30H30AlN3
C72H100Al2N6
O0.50
C27.33H34.67
Al0.67N1.33
P0.67
.25Si
Si0.5
Formula
weight
556.83
283.43
572.59
1143.58
459.55
1111.54
420.53
Crystal habit
Crystal color
block
block
block
Block
Block
block
block
colorless
200(2)
colorless
200(2)
colorless
200(2)
colorless
200(2)
Colorless
200(2)
colorless
200(2)
colorless
200(2)
Temperature,
K
Wavelength,
Å
0.71073
0.71073
0.71073
0.71073
0.71073
0.71073
0.71073
Crystal system Monoclinic
Triclinic
Pꢀ1
Triclinic
Pꢀ1
Orthorhombic Monoclinic
Triclinic
Pꢀ1
Monoclinic
P2(1)/c
Space group
P2(1)/n
Ibam
P2(1)/m
Unit cell diꢀ
mensions:
a, Å
b, Å
c, Å
a, °
9.6330(5)
16.9749(8)
20.9503(10)
90
12.0366(12)
12.3508(13)
12.6164(13)
70.633(6)
9.3319(3)
16.3923(4)
19.8520(6)
21.4153(6)
90
8.9717(3)
19.8654(7)
10.1194(4)
90
11.9759(9)
12.3948(8)
24.9637(17)
104.188(3)
93.639(4)
90.242(4)
3584.6(4)
17.2991(7)
12.1331(6)
18.0903(8)
90
11.6691(3)
17.0064(5)
80.3490(10)
75.2380(10)
88.0350(10)
1765.37(9)
b, °
g, °
93.418(3)
90
87.367(6)
90
113.658(2)
90
100.282(2)
90
79.059(6)
90
3
3419.7(3)
1737.0(3)
6969.0(3)
1651.97(10)
3736.0(3)
Volume, Å
Z
4
4
2
4
4
2
6
Density (calc), 1.082
1.084
1.077
1.090
1.848
1.030
1.121
3
Mg/m
Absorption
0.119
1208
0.118
616
0.088
624
0.085
2480
0.158
976
0.083
1208
0.127
1360
ꢀ1
coeff., mm
F(000)
Crystal size, 0.190 x 0.140 0.24 x 0.15 x 0.22 x 0.17 x 0.23 x 0.19 x 0.19 x 0.15 x 0.18 x 0.13 x 0.23 x 0.17 x
3
x 0.120
0.14
0.15
0.16
0.10
0.11
0.13
mm
2.28 to 28.31
1.71 to 26.43
1.77 to 28.32
1.61 to 28.32
2.05 to 28.32
2.38 to 24.81
2.03 to 28.33
θ
range for
data collection
Index ranges
ꢀ12<=h<=12, ꢀ ꢀ15<=h<=14, ꢀ ꢀ12<=h<=12, ꢀ ꢀ21<=h<=21, ꢀ ꢀ11<=h<=11, ꢀ ꢀ14<=h<=14, ꢀ ꢀ23<=h<=23, ꢀ
22<=k<=22, ꢀ 15<=k<=15, ꢀ 15<=k<=15, ꢀ 26<=k<=23, ꢀ 25<=k<=26, ꢀ 14<=k<=14, ꢀ 16<=k<=15, ꢀ
7
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27<=l<=27
26467
15<=l<=15
22062
22<=l<=22
26594
28<=l<=27
47830
13<=l<=13
22744
29<=l<=23
24915
24<=l<=23
52628
1
2
3
Reflections
collected
4
5
Independent
reflections
8338 [R(int) = 7090 [R(int) = 8702 [R(int) = 4465 [R(int) = 4213 [R(int) = 12063 [R(int) 9241 [R(int) =
0.0406]
0.0251]
0.0197]
0.0485]
0.0299]
= 0.0516]
0.0242]
6
7
8
9
Absorption
correction
Semiꢀ
None
Semiꢀ
None
None
Semiꢀ
empirical
from equivaꢀ from equivaꢀ
lents
Semiꢀ
empirical
empirical
from equivaꢀ
lents
empirical
from equivaꢀ
lents
lents
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Max. and min. 0.7457
and 0.9837
0.9723
and 0.9869
0.9809
and 0.9865
0.9807
and 0.9844
0.9706
and 0.9910
0.9853
and 0.9837
0.9715
and
transmission
0.6834
Refinement
method
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
Fullꢀmatrix
leastꢀsquares
2
2
2
2
2
2
2
on F
on F
on F
on F
on F
on F
on F
Data
/
reꢀ 8338
/
26
/
7090 / 0 / 369
8702 / 0 / 371
4465 / 0 / 209
4213 / 0 / 204
12063 / 18 / 9241 / 0 / 407
746
straints / paꢀ 377
rameters
Goodnessꢀofꢀ
1.039
1.064
1.032
1.042
1.043
1.011
1.012
2
fit on F
Final R indiꢀ R1 = 0.0488, R1 = 0.0507, R1 = 0.0506, R1 = 0.0447, R1 = 0.0456, R1 = 0.0689, R1 = 0.0500,
ces
wR2 = 0.1168 wR2 = 0.1247 wR2 = 0.1412 wR2 = 0.1171 wR2 = 0.1204 wR2 = 0.1628 wR2 = 0.1387
[I>2sigma(I)]
R indices (all R1 = 0.0898, R1 = 0.0672, R1 = 0.0641, R1 = 0.0644, R1 = 0.0624, R1 = 0.1329, R1 = 0.0631,
data) wR2 = 0.1326 wR2 = 0.1344 wR2 = 0.1532 wR2 = 0.1323 wR2 = 0.1308 wR2 = 0.1955 wR2 = 0.1516
Largest diff. 0.306 and
peak and hole, 0.173
ꢀ
0.413 and
0.314
ꢀ
0.555 and
0.354
ꢀ
0.456 and
0.254
ꢀ
0.258 and
0.219
ꢀ
0.418 and
0.316 e
ꢀ
0.525 and
0.364
ꢀ
ꢀ3
e.Å
(
(
10) (a) Frey, G. D.; Lavallo, V.; Donnadieu, B.; Schoeller, W. W.;
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1
2
3
4
5
6
7
8
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31
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33
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37
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39
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41
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43
44
45
46
47
48
49
50
51
52
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(
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(
23) Hill, M. S.; Hitchcock, P. B.; Pongtavornpinyo, R. Inorg. Chem.
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(
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(
(
(
(
(
(
43) SeydenꢀPenne, J. Reductions by the Alumino- and Borohydrides
in Organic Synthesis; WileyꢀVCH: New York, 1997.
44) Neutral hydrido aryloxides of Al are usually obtained by reactꢀ
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Mason, M. R.; Gravelle, P. W.; Bott, S. G.; Barron, A. R. J.
Chem. Soc., Dalton Trans. 1993, 441. (b) Campbell, J. P.; Gladꢀ
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2009, 9322.
(
(
45) Nöth, H.; Schlegel, A.; Knizek, J.; Krossing, I.; Ponikwar, W.;
Seifert, T. Chem. – Eur. J. 1998, 4, 2191.
(
(
(
46) (a) Shreve, A. P.; Mulhaupt, R.; Fultz, W.; Calabrese, J.; Robꢀ
bins, W.; Ittel, S. D. Organometallics 1988, 7, 409. (b) Clegg,
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(47) APEX Software Suite v.2010; Bruker AXS: Madison, WI, 2005.
(48) Blessing, R. Acta Cryst. 1995, A51, 33.
(49) Sheldrick, G.M. Acta Cryst. 2008, A64, 112.
(33) (a) J Gorden, J. D.; Voigt, A.; Macdonald, C. L. B.; Silverman,
J. S.; Cowley, A. H. J. Amer. Chem. Soc. 2000, 122, 950. (b)
Romero, P. E.; Piers, W. E.; Decker, S. A.; Chau, D.; Woo, T.
K.; Parvez, M. Organometallics 2003, 22, 1266.
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