Successful extrapolation of an f-element synthetic method to the pseudo light lanthanoid, aluminium

Article abstract of DOI:10.1016/j.jorganchem.2010.08.007

A redox transmetallation/ligand exchange reaction between Al metal, Hg(C₆F₅)₂ and 3,5-di-tert-butylpyrazole (tBu₂pzH) in tetrahydrofuran (thf) yields [Al(tBu₂pz) ₃(thf)] in which the six coordinate aluminium atom has two η²- and one η¹-tBu₂pz ligands. By contrast an analogous reaction in 1,2-dimethoxyethane (dme) gives the organoaluminium complex [Al₂(tBu₂pz)₃(C ₆F₅)₂(OCH₂CH₂OCH ₃)] in which each aluminium atom has an η²-pyrazolate and a C₆F₅ ligand and the Al atoms are bridged by an η¹:η¹-tBu₂pz ligand and a 2-methoxyethoxide ligand. In addition, [Al(tBu₂pz)₃] was isolated from the reaction mixture in a different form from that previously reprinted.

Full text of DOI:10.1016/j.jorganchem.2010.08.007

Journal of Organometallic Chemistry 695 (2010) 2720e2725
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Successful extrapolation of an f-element synthetic method to the pseudo light
lanthanoid, aluminium
,
a,c
Jacinta M. Bakker a, Leonard J. Barbour b, Glen B. Deacon a, Peter C. Junk a , Gareth O. Lloyd
,
*
Jonathan W. Steed c
a School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia
b Department of Chemistry, University of Stellenbosch, 7602, Matieland, South Africa
c Department of Chemistry, Durham University, South Road, Durham DH1 3LE, United Kingdom
a r t i c l e i n f o
a b s t r a c t
Article history:
A redox transmetallation/ligand exchange reaction between Al metal, Hg(C6F5)2 and 3,5-di-tert-butyl-
pyrazole (tBu2pzH) in tetrahydrofuran (thf) yields [Al(tBu2pz)3(thf)] in which the six coordinate
Received 8 July 2010
Received in revised form
4 August 2010
Accepted 6 August 2010
Available online 12 August 2010
aluminium atom has two
1,2-dimethoxyethane (dme) gives the organoaluminium complex [Al2(tBu2pz)3(C6F5)2(OCH2CH2OCH3)]
in which each aluminium atom has an
2-pyrazolate and a C6F5 ligand and the Al atoms are bridged by an
h1 1-tBu2pz ligand and a 2-methoxyethoxide ligand. In addition, [Al(tBu2pz)3] was isolated from the
reaction mixture in a different form from that previously reprinted.
Ó 2010 Elsevier B.V. All rights reserved.
h h
2- and one 1-tBu2pz ligands. By contrast an analogous reaction in
h
:h
Dedicated to Professor Herbert Schumann
the Father of German Organolanthanoid
Chemistry, a valued colleague and friend.
Keywords:
Redox transmetallation/ligand exchange
Aluminium complexes
Pyrazole and pyrazolates
High Z0
Crystallography
1. Introduction
crystal structure was determined.) using a metathesis method [2].
In this study, we report developments in the coordination chem-
istry of aluminium with tBu2pz through the use of a different
synthetic route, namely, the redox transmetallation/ligand
exchange reaction [6]. Such reactions (e.g. Scheme 1) have hitherto
been used to synthesise particularly f-element, but also Group 2
complexes [6], derivatives of elements more electropositive than
aluminium. Nevertheless, Al is a highly reactive metal and the
common oxidation state is the same as that of the f-element
complexes. It could thus be regarded as the lightest rare earth
metal. Further, the well-known preparations of homoleptic
aluminium alkyls and aryls from metallic aluminium and HgR2
species at elevated temperatures [7] suggested that aluminium
metal should participate in redox transmetallation/ligand exchange
reactions.
The coordination chemistry of pyrazolate anions and pyrazoles
has become a mainstay of inorganic chemistry.[1] Prior to 1997 the
coordination modes established for pyrazolates by crystallographic
means consisted of just the simple
me : ,
h1 h1 h1 and h2 modes
[1a,p,2]. However, post-1997, the possible modes of coordination
have increased substantially to over 20, resulting in such extreme
cases as me : :h h
h1 h2 1 (to Kþ and Tlþ) and 5 (to Ru2þ) [1a,3,4a]. The
synthesis of homoleptic pyrazolate complexes of d-block [4aec], f-
block [4def] and main group metals has also been achieved [2,3c,g].
3,5-Di-tert-butylpyrazole (tBu2pzH) is an archetypal ligand when it
comes to the coordination chemistry of the pyrazolates
[1a,2,3a,c,d,g,4bee,5]. Due to its simplicity in structure and it being
the bulkiest of the simple pyrazolates, it forms many types of
complexes with different metals [2,3c,4,5b]. We have previously
synthesised the homoleptic [Al(tBu2pz)3] (Compound 1; a trigonal
2. Results and discussion
Carrying out the redox transmetallation/ligand exchange reac-
tion shown in Scheme 1 using thf as the solvent resulted in
a complex of formula [Al(tBu2pz)3thf]$thf (2). The best yields of ca.
* Corresponding author. Fax: þ61 03 9905 4597.
E-mail address: peter.junk@monash.edu (P.C. Junk).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.08.007

J.M. Bakker et al. / Journal of Organometallic Chemistry 695 (2010) 2720e2725
2721
Scheme 1. Redox transmetallation/ligand exchange reaction between aluminium metal, 3,5-di-tert-butylpyrazole (tBu2pzH) and bis(pentafluorophenyl)mercury.
60% were achieved when the aluminium metal foil was cut into
strips that were as small as possible. Elemental mercury was used
for activation by surface amalgamation and the reaction was per-
formed in a sonic bath for between 48 and 72 h. After filtration and
reduction in the volume of the solution, crystals were formed over
time. Single crystal X-ray diffraction confirmed the formulation
coordination distorts the metal environment resulting in one of the
three tBu2pz ligands being
1-bonded, N1eAl11.8770(18), N2/Al1
1-pyrazolate coordination is long known
h
ꢀ
2.5610(18) A. Although
h
[1a,p], examples are relatively few, generally driven by coordina-
tion number (precious metals) [1a], or steric limitations
(compound 2), or H bonding to the free nitrogen atom [4f]. Even
(Fig. 1). Six coordinate compound 2 exhibits
h
2-coordination of two
though two tBu2pz ligands are h
2-bound, they have asymmetric
tBu2pz ligands in the same way as for 1. However, the h1 thf
AleN binding; bond lengths N3eAl1 1.8542(19); N4eAl1 2.3894
(19); N5eAl1 1.8794(18) and N6eAl 2.0304(18). Whilst the N5,6
ligand has a bite angle (Table 1) approaching that of homoleptic 1,
the more unsymmetrically coordinated N3,4 ligand has a much
narrower bite angle, typical of coordination to larger metals [1a].
Additionally, each pyrazolate ring is distorted away from copla-
narity with the coordination plane of the aluminium centre;
(interplanar angles between plane of tBu2pz and N1eN2eAl1 6.07
(17)ꢀ; N3eN4eAl1 17.06(14)ꢀ; N5eN6eAl1 25.49(14)ꢀ; calculated
using the MPLA function in SHELXL) [8]. tBu2pz coordination to four
coordinate Al can be distorted to either an unsymmetrical
h
2 or h1
(h
1 or h1 1) due to the steric bulkiness of the ligand [5a,c,d]. In
m
e
:h
six coordinate 2 these effects are exacerbated resulting in two
unsymmetrical h2 and one unidentate ligand. The average AleN
ꢀ
ꢀ
bond length (1.99 A) of 2 is longer than that of 1 (1.91 A) despite the
same coordination number, as thf is more bulky than half of an h2
-
tBu2pz ligand. Complex 2 is isolated as a thf solvate from a solution
in thf. The original metathesis synthesis of homoleptic 1 (trigonal
system form with approximate D3h symmetry) was carried out in
thf as well, but evaporation of the solution to dryness under
vacuum removed the thf from 2 to produce the homoleptic
compound before crystallisation from light petroleum [2]. The
lability of thf is also evident from the mass spectrum of 2 as no
signal is seen for any thf containing complex. Difficulty was expe-
rienced in obtaining a satisfactory C,H analysis (though N analysis
acceptable) for this air, moisture and thermally sensitive compound
but the composition was unequivocal both from the X-ray crystal
structure and the 1H NMR spectrum. The 27Al NMR spectrum in
C4D8O shows a broad resonance at 23.8 ppm and a narrower
resonance at 67.3 ppm (Section 4). The former is indicative of a six
Fig. 1. Ellipsoid plot of compound 2 showing the h2 and h1 coordination by tBu2pz to
Al. Hydrogen atoms and the interstitial thf have been removed for clarity. Ellipsoids are
shown at 50% probability.
coordinate low symmetry species and is attributed to a [Al(h1
-

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J.M. Bakker et al. / Journal of Organometallic Chemistry 695 (2010) 2720e2725
Table 1
Selected bond lengths and angles for compounds 1, 2 and one representative molecule of 4 (i ¼ 1 ꢁ y, x ꢁ y, z; ii ¼ 1 ꢁ x þ y, 1 ꢁ x, z).
Compound 1 Compound 2 Compound 4
Angles (ꢀ)
Bond lengths (A)
Angles (ꢀ)
Bond lengths (A)
Angles (ꢀ)
ꢀ
ꢀ
ꢀ
Bond lengths (A)
Al1eN1
Al1eN2
1.903(2)
1.911(2)
N1eAl1eN2
N1eAl1eN1i
N1eAl1eN2i
N1eAl1eN2ii
N2eAl1eN2ii
43.18 (9)
107.7 (1)
117.3 (1)
131.6 (1)
107.7 (1)
Al1eN3
Al1eN1
Al1eN5
Al1eO1
Al1eN6
Al1eN4
1.8542(19)
N3eAl1eN1
N3eAl1eN5
N1eAl1eN5
N3eAl1eO1
N1eAl1eO1
N5eAl1eO1
N3eAl1eN6
N1eAl1eN6
N5eAl1eN6
O1eAl1eN6
N3eAl1eN4
N1eAl1eN4
N5eAl1eN4
O1eAl1eN4
116.99(7)
121.24(8)
116.20(8)
101.64(7)
93.65(8)
98.11(7)
97.98(7)
108.37(8)
41.81(6)
139.51(6)
35.51(6)
149.89(7)
93.75(7)
84.61(6)
Al1eN1
1.901(2)
N1eAl1eN15
N1eAl1eN28
N15eAl1eN28
N1eAl1eN14
N15eAl1eN14
N28eAl1eN14
N1eAl1eN27
N15eAl1eN27
N28eAl1eN27
N14eAl1eN27
N1eAl1eN2
115.77(9)
132.01(9)
108.32(9)
107.41(9)
42.96(8)
117.67(9)
110.06(9)
130.66(9)
43.01(8)
106.55(9)
42.85(8)
107.15(9)
107.06(9)
131.66(9)
118.75(9)
1.8770(18)
1.8794(18)
1.9171(16)
2.0304(18)
2.3894(19)
Al1eN15
Al1eN28
Al1eN14
Al1eN27
Al1eN2
1.901(2)
1.902(2)
1.910(2)
1.913(2)
1.920(2)
N15eAl1eN2
N28eAl1eN2
N14eAl1eN2
N27eAl1eN2
tBu2pz)3(C4D8O)3] complex whilst the latter is nearer the region for
five coordination and the line width suggests higher symmetry [9].
A fully solvated Al(C4D8O)35þ species is a possible explanation. In
both cases the strong donor solvent either fully or partially (h2 to
(C6F5)3 precursor and a 2-methoxyethoxide anion, arising from the
cleavage of dme, leading to overall five coordination. One of the three
pyrazolate ligands and the methoxyethoxide ligand bridge the two
metal centres. The bridging pyrazolate ligand, binds me :h
h1 1 to the
h
1) displaces pyrazolate ligands. The reported 27Al NMR chemical
two metals with bond lengths of Al1eN3 1.954(3) and Al2eN41.949
(3) and a torsion angle of :Al1$N3$N4$Al2 34.3(3). The five
membered ring involving the bridged tBu2pz and OCH2CH2OCH3
ligands eAl1eN3eN4eAl2eO1e is not a common motif (only three
rings involving eAleNeNeAleOe were found in the CSD [10] and all
have pyrazolate ligands) [11] and is not planar (rms deviation from
shift for highly symmetric six coordinate 1 is 0 ppm [2]. The redox
transmetallation/ligand exchange reaction therefore is effective as
a means to synthesise products of ligated aluminium, and should
prove to have wide application. The essential role of the mercurial
in the reaction is evident since direct reaction of amalgamated
aluminium with TBPH in thf failed.
As thf plays an important role in the isolation of 2 and the
homoleptic compound 1, we attempted to study the effect that
a change of solvent would have on the reaction product in terms of
the coordination of solvent. We chose to use 1,2-dimethoxyethane
(dme), so that the bidentate coordinating ability of the solvent would
test if the aluminium coordination sphere could accommodate three
pyrazolate ligands and two coordinated solvent oxygen atoms.
However, the first compound isolated from this reaction was not
a simple pyrazolate ligated complex, but had the composition
[Al2(tBu2pz)3(C6F5)2(OCH2CH2OCH3)]$0.5 dme (3) (Fig. 2, Table 2).
The complex is dinuclear and contains three different ligands; the
pyrazolate anion, pentafluorophenyl ligands from the postulated Al
ꢀ
plane ¼ 0.1363 A; calculated using the MPLA function in SHELXL) [8].
The h2 pyrazolate ligands have bond lengths of Al1eN1 1.974(3);
Al1eN2 1.870(3) and Al2eN5 1.858(3); Al2eN6 2.054(3), with an
ꢀ
average value (1.94 A) similar to that of the
me
h1
:h
1-ligand (above),
ꢀ
somewhat greater than that (1.90 A) of six coordinate 1, but below
that (1.99 A) of six coordinate 2. These two ligands are coplanar with
ꢀ
the Al/N coordination plane (interplanar angles of N1eN2eAl1 2.67
(15)ꢀ and N5eN6eAl2 3.37 (9)ꢀ). In addition, the chelation bite
angles approach that of 1 and are similar to that of the more
symmetrical h
2-tBu2pz ligand of 2. The AleO bond lengths (Table 1)
are considerably shorter than those of 2 consistent with the lower
coordination number of 3. The 2-methoxyethoxide anion is the
product of the cleavage of the solvent dme and is relatively unusual,
although there are precedents [12]. More usually, methoxide
complexes are isolated (e.g. [6d,12g]). A 2-methoxyethoxide is
Table 2
Selected bond lengths and angles for compound 3
(ꢀ)
ꢀ
Bonds
Lengths (A)
Angles
Al1eO1
Al1eN2
Al1eN3
Al1eN1
Al1eC37
Al2eN5
Al2eN4
Al2eC43
Al2eN6
Al2eO1
1.821(2)
1.870(3)
1.954(3)
1.974(3)
2.008(4)
1.858(3)
1.949(3)
2.007(4)
2.054(3)
1.807(3)
O1eAl1eN2
O1eAl1eN3
N2eAl1eN3
O1eAl1eN1
N2eAl1eN1
N3eAl1eN1
O1eAl1eC37
N2eAl1eC37
N3eAl1eC37
N1eAl1eC37
O1eAl2eN5
O1eAl2eN4
N5eAl2eN4
O1eAl2eC43
N5eAl2eC43
N4eAl2eC43
O1eAl2eN6
N5eAl2eN6
N4eAl2eN6
111.50(13)
90.71(12)
104.00(13)
100.86(12)
42.69(12)
146.68(12)
110.15(13)
127.78(14)
105.56(13)
99.60(14)
111.87(13)
91.46(12)
105.87(13)
109.04(14)
125.83(14)
107.01(13)
99.39(12)
41.59(11)
147.39(13)
Fig. 2. Ellipsoid plot of compound 3 showing the ligation of aluminium by C6F5, tBu2pz
and a 2-methoxyethoxide anion in a bimetallic complex. Hydrogen atoms, the inter-
stitial dme, and the t-butyl groups have been removed for clarity. Ellipsoids are shown
at 30% probability.

J.M. Bakker et al. / Journal of Organometallic Chemistry 695 (2010) 2720e2725
2723
a homoleptic solvent free complex with Z0 [15] of one. However,
there are void channels (Fig 4a) that could hold disordered hexane
(crystallized from light petroleum) though it was not modelled in
the reported structure. The microanalysis [2] could accommodate
1/3.hexane within acceptable limits. In the new structure (4) there is
no solvent present, and the packing is compact (Fig. 4b). Thus, the
crystal structure of 1 may have contained a little disordered hexane,
or these may be two crystal forms of [Al(tBu2pz)3]. The four crys-
tallographically independent molecules found within the new
structure 4 show a similar approximate D3h symmetry to 1. However,
the symmetry can be described as almost C3 symmetry due to the
twisting of the planes of the pyrazolate ligands. This twisting is
opposite on neighbouring columns (related by P-1 symmetry) in 1
and is also evident in 4. One of the most noticeable differences
between 4 and 1 is the orientation of the two t-butyl groups on
tBu2pz in relation to each other. In 1 the orientation is staggered,
with a torsion angle of ca. 32.5ꢀ. In 4 this is not always the case. Of the
twelve examples, two are eclipsed (torsion angles of ca. 1.2ꢀ and ca.
5.6ꢀ). The other ten ꢀstaggered groups have torsion angles ranging
ꢀ
ꢀ
from ca. 25 to ca. 52 . The bond length range (1.868(2)e1.989(2) A)
of 4 is far wider than that of 1 (Table 1), and all bite angles are less
than those of 1, but mostly not by the three e.s.d. criterion.
Fig. 3. One of the four unique molecules in the X-raycrystalstructure of [Al(tBu2pz)3] (4).
3. Conclusions
observed in [Al(CH2SiMe3)2(OCH2CH2OCH3)]2 [12e], but the ligand is
not only bridging, it also has OCH3 coordination, in contrast to 3. The
bonds between the aluminium and the C6F5 ligands (Al1eC37 2.008
(4) and Al2eC43 2.007(4)) match well with the average distance
AleC 1.997(52) for C6F5 to Al in the crystal structures observed and
reported in the CSD [13]. The 27Al NMR chemical shift of 3 in the non
coordinating solvent C6D6 is near the region for five coordinate Al
species and the very broad signal is consistent with a low symmetry
mixed ligand complex suggesting the structural integrity is main-
tained in C6D6 [9]. The serendipitous formation of compound 3
provides evidence that the redox transmetallation/ligand exchange
reaction does indeed go through an AleC6F5 complex intermediate
and not a mercury tBu2pz complex. Compound 3 represents a small
percentage of the reaction products (ca. 23%). As well as 3, unreacted
tBu2pzH (ca. 40%) and the homoleptic compound [Al(tBu2pz)3] (4, ca.
37%) were found.
We have shown that the redox transmetallation/ligand exchange
reaction can be used to prepare aluminium complexes starting with
simple “off the supermarket shelf” aluminium foil in reasonable
yield. This one pot methodology allows for easy separation of
products as the elemental mercury produced is filtered off (with the
excess aluminium foil) and the pentafluorobenzene is easily evapo-
rated leaving products and unreacted 3,5-di-tert-butylpyrazole. In
this reaction, the putative intermediate Al(C6F5)3 is never isolated
andpurified, as this compound can result in the explosive production
of aluminium fluorides [16]. The complexes reported herein reveal
the solvent ligand binding ability of the [Al(tBu2pz)3] complex.
Tetrahydrofuran can coordinate but without a coordination number
increase owing to an h2
/ h
1-tBu2pz bonding change. More steri-
cally demanding solvents such as dme do not appear to be able to
bind even if they are potential chelators. The cleavage of dme during
this reaction is also interesting and formation of 3 provides evidence
for an Al(C6F5)3 intermediate. Further experiments are underway to
investigate the possibilities of using the redox transmetallation/
ligand exchange reaction with Al and other ligands, as well as
extensions to other electropositive elements. Indeed, success has
been recently achieved with the synthesis of manganese(II) aryl-
oxides [17].
The homoleptic complex [Al(tBu2pz)3] (4) (Fig. 3) does not
contain metal-bound dme solvent (Fig. 3). The isolation of this
complex suggests that dme cannot replace even one tBu2pz nitrogen
since unidentate dme coordination is known. Analogously [YbCp2F]3
is isolated from dme [14a] in contrast to [YbCp2F(thf)]2 from thf
[14b]. The crystal structure reported previously [2] of 1 (Fig. 4a) is
Fig. 4. (a) Figure of the homoleptic compound Al(tBu2pz)3 1 channel structure. (b) High Z0 structure (Z0 ¼ 4) of the homoleptic compound Al(tBu2pz)3 4. There are four asymmetric
units. All structures shown in capped-stick representation.

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J.M. Bakker et al. / Journal of Organometallic Chemistry 695 (2010) 2720e2725
4. Experimental section
immersed in viscous hydrocarbon oil and mounted on a glass fibre
which was mounted on the diffractometer. Reflections were
The compounds described are all air- and moisture-sensitive. All
manipulations were carried out under purified nitrogen using
standard Schlenk techniques. Solvents (thf, dme, toluene and
hexane) were dried and deoxygenated by refluxing over blue sodium
benzophenone ketyl under purified nitrogen. Solvents were distilled
directly into storage flasks equipped with Teflon taps and stored
under nitrogen. Elemental analyses (C, H, N) were performed by The
Campbell Microanalytical Laboratory, Chemistry Department,
University of Otago, Dunedin, New Zealand. I.R. spectra were
obtained as Nujol mulls with a Perkin Elmer 1600 FTIR instrument.
The n.m.r. spectra were recorded on a Bruker AM300 spectrometer,
and data were referenced to either the residual protonated solvent
signals or a solution of an external standard (Al(NO3)3, 0.67 M (aq),
measured using psi and omega scans and were reduced to unique
reflections, with Fo > 2s(Fo) being considered observed. Data were
initially processed and corrected for absorption using the programs
DENZO [19] and SORTAV [20]. The structures were solved using
direct methods, and observed reflections were used in least squares
refinement on F2, with anisotropic thermal parameters refined for
non-hydrogen atoms. Hydrogen atoms were constrained in calcu-
lated positions and refined with a riding model. Structure solutions
and refinements were performed using the programs SHELXS-97
[21] and SHELXL-97 [22] through the graphical interface X-Seed
[23], which was also used to generate the figures.
Crystal data for 2: C41H73AlN6O2, M ¼ 709.03, colourless rect-
angular prism, 0.39 ꢂ 0.36 ꢂ 0.31 mm3, monoclinic, space group
27Al
d
¼ 0.0). Chemicals were purchased from Aldrich and were used
P21/c (No. 14), a ¼ 11.934(7), b ¼ 19.011(10), c ¼ 19.148(12) A,
ꢀ
3
as received. Standard aluminium foil was used. Syntheses of 3,5-di-
tert-butylpyrazole [18a] and bis(pentafluorophenyl)mercury [18b]
have been described previously.
b
¼ 101.095(15)ꢀ, V ¼ 4263(4) A , Z ¼ 4, Dc ¼ 1.105 g/cm3,
ꢀ
F000 ¼ 1560,
2
qmax ¼ 53.0ꢀ, 31846 reflections collected, 8799
unique
(Rint ¼ 0.0467).
Final
GooF ¼ 1.029,
R1 ¼0.0548,
(I)
In a typical experiment, a large excess of Al foil (cut into small
strips, 0.500 g, 18.5 mmol) was combined with tBu2pzH (0.911 g,
5.06 mmol), Hg(C6F5)2 (1.38 g, 2.58 mmol) and 2 drops of elemental
mercury in a Schlenk flask. These starting materials were dried under
vacuum for ca. 3 h prior to the addition of thf (compound 2) or dme
(compound 3) (50 ml). The reaction vessel was placed in a sonic bath
for 48e72 h. After this time, the precipitated mercury and excess
aluminium were left to settle to the bottom of the reaction mixture.
The reaction solution was separated through a filter cannula,
concentrated to crystallisation and stored at ambient temperature or
cooled to 5 ꢀC until single crystals of the product deposited (2 or 3).
The filtrate following isolation of 3 was evaporated until precipita-
tion began. After heating to dissolve this precipitate, and standing at
room temperature overnight, crystals of 4 deposited. The mother
liquor was removed by cannula leaving 4 (37%), and evaporated to
dryness leaving unreacted 3,5-di-tert-butylpyrazole (40%).
wR2 ¼ 0.1237, R indices based on 6473 reflections with I > 2
s
(refinement on F2), 497 parameters, 34 restraints. Lp and absorp-
tion corrections applied,
m
¼ 0.087 mmꢁ1
.
Crystal data for 3.0.5dme: C50H69Al2F10N6O3, M ¼ 1046.07, col-
ourless block, 0.40 ꢂ 0.38 ꢂ 0.25 mm3, triclinic, space group P-1 (No.
ꢀ
2), a ¼ 10.618(2), b ¼ 12.964(3), c ¼ 20.759(4) A,
a
¼ 73.27(3),
3
3
ꢀ
ꢀ
b
¼ 76.49(3),
g
¼ 87.32(3) , V ¼ 2660.1(9) A , Z ¼ 2, Dc ¼ 1.306 g/cm ,
F000 ¼ 1102, 2qmax ¼ 52.0ꢀ, 32,892reflectionscollected,10,390 unique
(Rint ¼ 0.0796). Final GooF ¼ 1.036, R1 ¼0.0697, wR2 ¼ 0.1778, R
indices based on 5682 reflections with I > 2s
(I) (refinement on F2),
695 parameters, 0 restraints. Lp and absorption corrections applied,
m
¼ 0.136 mmꢁ1
.
Crystal data for 4: C33H57N6Al1, M ¼ 564.83, colourless prism,
0.45 ꢂ 0.21 ꢂ0.18 mm3, triclinic, space group P-1 (No. 2), a ¼ 10.4999
ꢀ
(5), b ¼ 19.4670(10), c ¼ 33.9263(18) A,
a
¼ 91.127(3),
b
¼ 92.024
3
(2),
g
¼ 97.265(2)ꢀ, V ¼ 6872.6(6) A , Z ¼ 8, Dc ¼ 1.092 g/cm3,
ꢀ
Analytical data: Compound 2: 1H n.m.r. (C4D8O) 1.15, s, 54H,
F000 ¼ 2480, 2qmax ¼ 55.0ꢀ, 142,018 reflections collected, 31,492
unique (Rint ¼ 0.0448). Final GooF ¼ 1.107, R1 ¼0.0781, wR2 ¼ 0.1757,
(tBu); 5.91, s, 3H, (-CH-) 27Al n.m.r. (C4D8O)
d (W1/2 Hz) 23.8 (1800)
and 67.3 (130). I.r. absorption: 2955s; 2924s; 2845s; 1511m; 1462s;
1375s; 1309w; 1257s; 1232w; 1204w; 1075s; 992w; 960w; 915w;
796w; 723s. Mass Spectrum: m/z 564.4 (46%, Al(tBu2pz)þ3 ), 385.3
(100%, M-tBu2pzþ). Elemental analysis: Calculated for C41H73AlN6O2
(709.08): C 69.5%, H 10.4%, N 11.9% Observed: C 67.0%, H 9.7%, N
12.0%. Compound 3: 1H n.m.r. (C6D6) 1.22, s, 54H, (tBu); 3.12, m, 8H,
(eOeCH2e); 3.33, m, 9H (eCH3); 5.98, s, 3H, (eCHe) 27Al n.m.r.
R indices based on 24,910 reflections with I > 2s
(I) (refinementon F2),
1442 parameters, 0 restraints. Lp and absorption corrections applied,
m
¼ 0.089 mmꢁ1
.
Acknowledgements
We thank the Leverhulme Trust and GOL thanks the Common-
wealth Scholarship Commission for funding. We also acknowledge
the Australian Research Council and the Monash Graduate School
for a scholarship (JMB).
(C6D6)
d
(W1/2 Hz) 77.9 (4600). 19F n.m.r. ((C6D6)) ꢁ119.7, m, 4F, F2,6;
ꢁ154.4, m, 2F, F4; ꢁ 162.5, m, 4F, F3,5. I.r. absorption: 2934s; 2848s;
1635m; 1507m; 1456s; 1380m; 1365m; 1303w; 1268w; 1252w;
1227w; 1205w; 1125w; 1069m; 962m; 804m; 799m; 722w; 666w.
Mass Spectrum: m/z 821.3 (18%, M-tBu2pzHþ), 225.1 (100%, [Al
(C6F5)OMe]þ). No molecular ion peak was seen. Elemental analysis:
Calculated for C48H64Al2F10N6O2 (1000.99 e loss of dme of solva-
tion): C 57.6%, H 6.4%, N 8.4% Observed: C 57.4%, H 7.5%, N 8.4%.
Attempted reaction of amalgamated aluminium with TBPH: A
large excess of oven dried Al foil (cut into small strips, 0.14 g,
5.10 mmol) was combined with dried TBPH (0.911 g, 5.06 mmol),
and two drops of elemental mercury and thf (30 ml) were added.
After sonication for 3d the reaction solution was passed through
a filter cannula and concentrated to dryness. IR (strong NH band)
and 1H NMR (1:1 ratio of amine and backbone proton signals)
spectra indicated the resulting powder was TBPH.
Appendix A. Supplementary material
Crystallographic data (excluding structure factors) for the
structures reported in this paper have been deposited with the
Cambridge Crystallographic Data Centre as supplementary publi-
cation no. CCDC-745488 for 2, CCDC-745489 for 3 and CCDC-
745490 for 4. Copies of the data can be obtained free of charge on
application to The Director, CCDC, 12 Union Road, Cambridge, CB2
1EZ, UK (fax: þ44 1223 336 033; email for inquiry: fileserv@ccdc.
cam.ac.uk; email for deposition: deposit@ccdc.cam.ac.uk).
References
[1] (a) M.A. Halcrow, Dalton Trans. (2009) 2059;
5. X-ray structure determinations
(b) A.Y. O’Brien, J. Hitzbleck, A. Torvisco, G.B. Deacon, K. Ruhlandt-Senge, Eur. J.
Inorg. Chem. (2008) 172;
(c) S. Nieto, J. Perez, L. Riera, V. Riera, D. Miguel, Chem. Eur. J. 12 (2006) 2244;
(d) S. Trofimenko, Chem. Rev. 72 (1972) 497;
Intensity data were collected using an Enraf-Nonius KAPPA CCD
ꢀ
at 123 K with Mo-K
a
radiation (
l
¼ 0.7170 A). Suitable crystals were

J.M. Bakker et al. / Journal of Organometallic Chemistry 695 (2010) 2720e2725
2725
(e) M.A. Omary, O. Elbjeirami, C.S.P. Gamage, K.M. Sherman, H.V.R. Dias, Inorg.
Chem. 48 (2009) 1784;
(d) G.B. Deacon, P.C. Junk, G.J. Moxey, M. Guino, K. Ruhlandt-Senge, Dalton
Trans. (2009) 4878.
(f) I. Saeed, S. Katao, K. Nomura, Inorg. Chem. 48 (2009) 5011;
(g) R. Mukherjee, Coord. Chem. Rev. 203 (2000) 151;
(h) F. Mani, Coord. Chem. Rev. 120 (1992) 325;
[7] (a) J.J. Eisch, Aluminium. in: G. Wilkinson, F.G.A. Stone, E.W. Abel (Eds.),
Comprehensive Organometallic Chemistry, vol. 1. Pergamon, Oxford, 1982
Chapter 6;
(i) T.A. Kaden, Coord. Chem. Rev. 192 (1999) 371;
(b) S. Dagorne, D.A. Atwood, Chem. Rev. 108 (2008) 4037;
(c) J. Alcantara-Garcia, V. Jancik, J. Barroso, S. Hidalgo-Bonilla, R. Cea-Olivares,
R.A. Toscano, M. Moya-Cabrera, Inorg. Chem. 48 (2009) 5874.
[8] G.M. Sheldrick, Acta Crystallogr. Sect. A 64 (2008) 112.
[9] (a) H. Haraguchi, S. Fujiwara, J. Phys. Chem. 73 (1969) 3467;
(b) R. Benn, A. Rufinska, Angew Chem. Int. Ed. Engl. 25 (1986) 861.
[10] CSD, version 1.11; May 2009 update, Cambridge Crystallographic Data Centre.
[11] (a) Z.K. Yu, J.M. Wittbrodt, A.B. Xia, M.J. Heeg, H.B. Schlegel, C.H. Winter,
Organometallics 20 (2001) 4301;
(j) M.D. Ward, J.A. McCleverty, J.C. Jeffery, Coord. Chem. Rev. 222 (2001) 251;
(k) K.R. Gust, J.E. Knox, M.J. Heeg, H.B. Schlegel, C.H. Winter, Eur. J. Inorg.
Chem. (2002) 2327;
(l) K.R. Gust, J.E. Knox, M.J. Heeg, H.B. Schlegel, C.H. Winter, Angew Chem. Int.
Ed. 41 (2002) 1591;
(m) S. Trofimenko, Prog. Inorg. Chem. 34 (1986) 115;
(n) A.W. Addison, P.J. Burke, J. Heterocycl. Chem. 18 (1981) 803;
(o) T. Basu, H.A. Sparkes, M.K. Bhunia, R. Mondal, Cryst. Growth Des. 9 (2009)
3488;
(b) W.J. Zheng, N.C. Mosch-Zanetti, H.W. Roesky, M. Noltemeyer, M. Hewitt,
H.G. Schmidt, T.R. Schneider, Angew Chem. Int. Ed. 39 (2000) 4276.
[12] (a) W. Uhl, Coord. Chem. Rev. 163 (1997) 1;
(p) J.E. Cosgriff, G.B. Deacon, Angew Chem. Int. Ed. 37 (1998) 286;
(q) D. Pfeiffer, M.J. Heeg, C.H. Winter, Angew Chem. Int. Ed. 37 (1998) 2517.
[2] G.B. Deacon, E.E. Delbridge, C.M. Forsyth, P.C. Junk, B.W. Skelton, A.H. White,
Aust. J. Chem. 52 (1999) 733.
(b) W.K. Wong, L. Zhang, F. Xue, T.C.W. Mak, J. Chem. Soc. Dalton Trans. (1999)
3053;
[3] (a) C. Yelamos, M.J. Heeg, C.H. Winter, Inorg. Chem. 37 (1998) 3892;
(b) G.B. Deacon, E.E. Delbridge, C.M. Forsyth, B.W. Skelton, A.H. White, J. Chem.
Soc. Dalton Trans. (2000) 745;
(c) W. Uhl, A. Vester, D. Fenske, G. Baum, J. Organomet. Chem. 464 (1994) 23;
(d) A. Ecker, R. Koppe, C. Uffing, H. Schnöckel, Z. Anorg. Allg. Chem. 624 (1998)
817;
(c) S. Beaini, G.B. Deacon, A.P. Erven, P.C. Junk, D.R. Turner, Chem. Asian J. 2
(2007) 539;
(e) M. Westerhausen, C. Birg, H. Nöth, J. Knizek, T. Seifert, Eur. J. Inorg. Chem.
(1999) 2209;
(d) J.R. Perera, M.J. Heeg, H.B. Schlegel, C.H. Winter, J. Am. Chem. Soc. 121
(1999) 4536;
(f) D. Britnell, M.G.B. Drew, G.W.A. Fowles, D.A. Rice, Inorg. Nucl. Chem. Lett. 9
(1973) 415;
(e) S. Beaini, G.B. Deacon, E.E. Delbridge, P.C. Junk, B.W. Skelton, A.H. White,
Eur. J. Inorg. Chem. (2008) 4586;
(f) N.C. Mösch-Zanetti, R. Kratzner, C. Lehmann, T.R. Schneider, I. Uson, Eur. J.
Inorg. Chem. (2000) 13;
(g) J. Hitzbleck, G.B. Deacon, K. Ruhlandt-Senge, Angew Chem. Int. Ed. 43
(2004) 5218.
(g) G.B. Deacon, P.C. Junk, G.J. Moxey, Z. Anorg. Allg. Chem. 634 (2008) 2789.
[13] CCDC Vista. Cambridge Crystallographic Data Centre, Cambridge, United
Kingdom, 1994.
[14] (a) G.B. Deacon, D. Stellfeldt, G. Meyer, Eur. J. Inorg. Chem. (2000) 1061;
(b) G.B. Deacon, S.C. Harris, G. Meyer, D. Stellfeldt, D.L. Wilkinson, G. Zelesny,
J. Organomet. Chem. 552 (1998) 165.
[4] (a) I.A. Guzei, A.G. Baboul, G.P.A. Yap, A.L. Rheingold, H.B. Schlegel, C.H. Winter,
J. Am. Chem. Soc. 119 (1997) 3387 Typical examples: d block:;
(b) I.A. Guzei, G.P.A. Yap, C.H. Winter, Inorg. Chem. 36 (1997) 1738;
(c) O.M. El-Kadri, M.J. Heeg, C.H. Winter, Inorg. Chem. 45 (2006) 5278 f-block;
(d) G.B. Deacon, A. Gitlits, B.W. Skelton, A.H. White, Chem. Commun. (1999)
1213;
[15] (a) J.W. Steed, CrystEngComm (2003) 169;
(b) K.M. Anderson, M.R. Probert, C.N. Whiteley, A.M. Rowland, A.E. Goeta,
J.W. Steed, Cryst. Growth. Des. 9 (2009) 1082;
(c) K.M. Anderson, A.E. Goeta, J.W. Steed, Cryst. Growth Des. 8 (2008) 2517;
(d) K.M. Anderson, J.W. Steed, CrystEngComm 9 (2007) 328;
(e) G.R. Desiraju, CrystEngComm 9 (2007) 91.
(e) G.B. Deacon, A. Gitlits, P.W. Roesky, M.R. Burgstein, K.C. Lim, B.W. Skelton,
A.H. White, Chem. Eur. J. 7 (2001) 127;
[16] T. Belgardt, J. Storre, H.W. Roesky, M. Noltemeyer, H.G. Schmidt, Inorg. Chem.
34 (1995) 3821.
(f) G.B. Deacon, C.M. Forsyth, A. Gitlits, R. Harika, P.C. Junk, B.W. Skelton,
A.H. White, Angew Chem. Int. Ed. 41 (2002) 3249.
[17] G.B. Deacon, L.Y. Goh, W.R. Jackson, B.W. Skelton, W. Chen, A.H. White, Z.
Anorg. Allg. Chem. 636 (2010) 1478.
[5] (a) Z.K. Yu, J.E. Knox, A.V. Korolov, M.J. Heeg, H.B. Schlegel, C.H. Winter, Eur. J.
Inorg. Chem. (2005) 330;
[18] (a) J. Elguero, E. Gonzales, R. Jacquier, Bull. Soc. Chim. Fr. (1968) 707;
(b) G.B. Deacon, J.E. Cosgriff, E.T. Laurenz, C.M. Forsyth, D.L. Wilkinson, in:
W.A. Hermann, F.T. Edelmann (Eds.), Synthetic Methods in Organometallic
and Inorganic Chemistry (Hermann/Brauer), vol. 6, Thieme, NewYork, 1997,
pp. 48e51.
[19] Z. Otwinowski, W. Minor, Methods Enzymol. 276 (1997) 307.
[20] R.H. Blessing, Acta Crystallogr. Sect. A 51 (1995) 33.
[21] G.M. Sheldrick, SHELXS-97 Program for Crystal Structure Solution. University
of Göttingen, Germany, 1997.
(b) G.B. Deacon, E.E. Delbridge, D.J. Evans, R. Harika, P.C. Junk, B.W. Skelton,
A.H. White, Chem. Eur. J. 10 (2004) 1193;
(c) W.J. Zheng, N.C. Mosch-Zanetti, T. Blunck, H.W. Roesky, M. Noltemeyer,
H.G. Schmidt, Organometallics 20 (2001) 3299;
(d) W.J. Zheng, H.W. Roesky, M. Noltemeyer, Organometallics 20 (2001) 1033.
[6] (a) G.B. Deacon, G.D. Fallon, C.M. Forsyth, S.C. Harris, P.C. Junk, B.W. Skelton,
A.H. White, Dalton Trans. (2006) 802;
(b) M.L. Cole, P.C. Junk, New J. Chem. 29 (2005) 135;
(c) G.B. Deacon, C.M. Forsyth, S. Nickel, J. Organomet. Chem. 647 (2002) 50 and
references therein;
[22] G.M. Sheldrick, SHELXL-97 Program for Crystal Structure Refinement.
University of Göttingen, Germany, 1997.
[23] L.J. Barbour, Supramol. Chem. 1 (2001) 189.