Synthetic and structural studies on aluminium thiolate complexes

Article abstract of DOI:10.1016/S0277-5387(03)00351-6

The reaction between [AlH₃(NMe₂Et)] and 1 equiv. of t-BuSH resulted in the isolation of colourless crystals of [Al(S-t-Bu)₃(NMe₂Et)]. The reaction of [AlH₃(NMe₂Et)] and 1 equiv. of 2,6-Me

Full text of DOI:10.1016/S0277-5387(03)00351-6

Polyhedron 22 (2003) 2655ꢂ2660
/
www.elsevier.com/locate/poly
Synthetic and structural studies on aluminium thiolate complexes
Claire J. Carmalt a,*, John D. Mileham a, Andrew J.P. White b, David J. Williams b,
Simon Rushworth c
a Department of Chemistry, Christopher Ingold Laboratories, University College London, 20 Gordon Street, London, WC1H 0AJ, UK
b Department of Chemistry, Imperial College London, South Kensington, London, SW7 2AZ, UK
c Epichem Limited, Power Road, Bromborough, Wirral, CH62 3QF UK
Received 31 March 2003; accepted 12 May 2003
Abstract
The reaction between [AlH3(NMe2Et)] and 1 equiv. of t-BuSH resulted in the isolation of colourless crystals of [Al(SÃ
/
t-
Bu)3(NMe2Et)]. The reaction of [AlH3(NMe2Et)] and 1 equiv. of 2,6-Me2C6H3SH afforded colourless crystals of [HNMe2Et]-
[Al(SC6H3Me2-2,6)4]. The related reaction of [AlH3(OEt2)] (generated in situ from AlCl3 and 3 equiv. of LiAlH4) and 2,6-
Me2C6H3SH in diethyl ether resulted in the formation of [Al(SC6H3Me2-2,6)3(OEt2)]. However, the ionic compound
[Li(OEt2)3][Al(SC6H3Me2-2,6)4] can be isolated from the reaction between [AlH3(OEt2)] and 2,6-Me2C6H3SH, when incomplete
reaction of AlCl3 with LiAlH4 occurs before the addition of the thiol. The X-ray crystal structures of all the compounds have been
determined.
# 2003 Elsevier Ltd. All rights reserved.
Keywords: Aluminium; Thiolate; Hydride
1. Introduction
Most of the aluminium thiolate complexes are prepared
from salt elimination routes or triorganoaluminium
Organometallic
compounds,
AlꢂTl; Eꢁ
alkyl or aryl) have been studied for many years [1].
of
the
type
compounds [1ꢂ6]. However, there are relatively few
reports of reactions between thiols and aluminium
hydrides [2,4,7,8].
/
[RnM(ER?)3ꢀn] (where Mꢁ
/
/
/
SꢂTe; R and
/
R?ꢁ
/
We were interested in exploring the reactivity of alane
with thiols in more detail in an attempt to obtain
structural information on mixed hydrido-thiolate com-
plexes of aluminium. In related reactions of alane with
alcohols we isolated and structurally characterised some
pentanuclear alkoxyaluminium hydrides [9]. We were
also interested in hydridoaluminium thiolate complexes
because materials containing a Group 13 metal (Al, Ga,
In or Tl) and a chalcogen are reported to have
applications as precursors to III/VI materials, which
are potential alternatives to II/VI materials for photo-
More recently, structural information has shown that
these complexes have a tendency to form dimeric or
trimeric aggregates in the solid-state [1]. Monomeric
derivatives, of the type [M(ER)3], have only been studied
to a limited extent. With reference to aluminium
tris(thiolate) complexes, [Al(SR)3], structurally charac-
terised examples include [Al(SC6H2Ã
[Al(SR)3(L)] (LꢁHNMe2, Rꢁi-Pr; Lꢁ
or C6H2Ãi-Pr3-2,4,6) [2ꢂ4]. Lithium organo-tri(thiola-
to)aluminates, of the type [Li(thf)2Al{C(SiMe3)3}(SR)3]
(RꢁMe, Et, i-Pr or Ph) have been reported recently
and some of the complexes structurally characterised [5].
/t-Bu3-2,4,6)3] and
/
/
/
thf, Rꢁt-Bu
/
/
/
/
voltaic and optoelectronic devices [10ꢂ12].
/
Herein we describe the reactivity of alane with t-
BuSH and 2,6-Me2C6H3SH. The structures of four new
complexes, namely [Al(SÃ
Me2-2,6)3(OEt2)], [Li(OEt2)3][Al(SC6H3Me2-2,6)4] and
[HNMe2Et][Al(SC6H3Me2-2,6)4] are described.
/
t-Bu)3(NMe2Et)], [Al(SC6H3-
* Corresponding author. Tel: ꢃ
7463.
E-mail address: c.j.carmalt@ucl.ac.uk (C.J. Carmalt).
/
44-20-7679-7528; fax: ꢃ44-20-7679-
/
0277-5387/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved.
doi:10.1016/S0277-5387(03)00351-6

2656
C.J. Carmalt et al. / Polyhedron 22 (2003) 2655ꢂ2660
/
2. Results and discussion
Table 1
˚
Selected bond lengths (A) and angles (8) for 1
The reaction of [AlH3(NMe2Et)] and 1 equiv. of t-
BuSH in diethyl ether at room temperature resulted,
after work up, in the isolation of colourless crystals of
Bond lengths
AlÃ
AlÃ
S(1)Ã
S(3)Ã
/
N(1)
2.038(2)
2.2356(8)
1.852(2)
1.858(2)
AlÃ
AlÃ
S(2)ÃC(10)
/
S(1)
2.2366(8)
2.2337(8)
1.862(2)
/S(2)
/S(3)
/C(6)
/
[Al(SÃ
scopic data for 1 were consistent with the formation of
the tris(thiolate) complex [Al(SÃt-Bu)3(NMe2Et)] rather
/t-Bu)3(NMe2Et)] (1). Analytical and spectro-
/C(14)
Bond angles
N(1)ÃAlÃS(3)
S(3)ÃAlÃ
S(3)ÃAlÃ
C(6)Ã
C(14)Ã
/
/
/
101.16(6)
115.68(3)
116.21(3)
112.65(7)
112.46(8)
N(1)Ã
N(1)Ã
S(2)ÃAlÃ
C(10)ÃS(2)Ã
/
AlÃ
/
S(2)
104.00(6)
99.83(6)
than a hydridoaluminium thiolate. The X-ray structure
of 1 (Fig. 1, Table 1) shows the coordination geometry
at aluminium to be noticeably flattened tetrahedral, the
/
/
S(2)
S(1)
/
AlÃ
/S(1)
/
/
/
/
S(1)
116.17(4)
112.91(7)
/
S(1)Ã
S(3)Ã
/
Al
Al
/
/Al
/
/
NÃ
104.00(6)8, whereas those for SÃ
115.68(3)8 and 116.21(3)8 with the aluminium atom
/
AlÃ
/
S
angles ranging between 99.83(6)8 and
/
AlÃS are between
/
˚
lying 0.45 A out of the S3 plane. This geometry is
directly analogous to that observed in [Al(SÃt-Bu)3(thf)]
and [Al(SÃi-Pr)3(HNMe2)] where the geometry at
aluminium was described as distorted trigonal pyrami-
dal [3]. In the present structure the sum of the three SÃ
AlÃS angles is 3488, a value virtually identical to those
reported for t-Bu)3(thf)] and [Al(SÃi-
[Al(SÃ
Pr)3(HNMe2)] (3488 and 3458, respectively [3]).
Although the three AlÃS distances are in a very narrow
range (2.2337(8)ꢂ2.2366(8) A) and there appears to be
an essentially C3-symmetric arrangement of the t-SBu
ligands with respect to the AlꢂN axis, this symmetry
does not extend to the torsion angles about the AlÃ
bonds, with the twists relative to the AlꢂN vector
/
/
/
/
/
/
/
˚
/
/
/
S
/
Scheme 1.
ranging between 1098 and 1378. There are no inter-
molecular packing interactions of note.
Compound 1 was the only species isolated from the
reaction of [AlH3(NMe2Et)] with t-BuSH and the
prepare compound 1 was higher (room temperature vs.
15 8C) which may result in ligand redistribution
reactions occurring. It is possible that [H2Al(SÃt-
Bu)(NMe2Et)] or [HAl(SÃt-Bu)2(NMe2Et)] was formed
during the reaction but ligand exchange occurred to give
1 and [AlH3]. The formation of a tris(thiolate) complex
has been observed previously in related gallium thiolate
chemistry [13]. Thus, the reaction between [GaH3-
(NMe3)] and 2 equiv. of t-BuSH was reported to yield
ꢀ
/
/
expected product [H2Al(SÃ
/
t-Bu)(NMe2Et)] was not
observed (Scheme 1). The formation of compound 1 is
/
in contrast to a previous report where the alkylthiola-
t-
toalanes, [H2Al(SÃ
/
t-Bu)(NMe3)] and [HAl(SÃ
/
Bu)2(NMe3)], were isolated from the reaction of
[AlH3(NMe3)] and 1 or 2 equiv. of t-BuSH, respectively
[8]. However, the reaction temperature employed to
[Ga(SÃ
/
t-Bu)3(NMe3)] and [HGa(SÃ
/
t-Bu)2(NMe3)] [13].
Compound 1 can be prepared in higher yield from the
reaction of [AlH3(NMe2Et)] and 3 equiv. of t-BuSH [3].
In order to investigate the reactivity of alane with
thiols in more detail, [AlH3(NMe2Et)] was treated with 1
equiv. of 2,6-Me2C6H3SH in diethyl ether (Scheme 1).
After work up a colourless crystalline product (2) was
obtained. The structure of 2 was established by X-ray
crystallography and shown to be the pseudo-homoleptic
complex [HNMe2Et][Al(SC6H3Me2-2,6)4], shown in Fig.
2 (Table 2). For the charges to balance either the
complex or the co-crystallised NMe2Et molecule has to
be protonated, but unfortunately it was not possible to
locate in difference electron maps a hydrogen atom on
any of the four sulfur atoms or on the nitrogen atom of
the NMe2Et. Inspection of the AlÃ
/
S bond lengths
Fig. 1. The molecular structure of 1.
showed that three of these, those to S(1), S(3) and

C.J. Carmalt et al. / Polyhedron 22 (2003) 2655ꢂ
/2660
2657
of a 1:1 mixture of 2 and the neutral complex
[Al(SC6H3Me2-2,6)3(NMe2Et)].
An alternative route was also investigated where
[AlH3] in diethyl ether was reacted with thiols. Thus,
the reaction between [AlH3(OEt2)] (generated in situ
according to Ref. [14]) and 1 equiv. of 2,6-Me2C6H3SH
in diethyl ether at room temperature resulted, after work
up, in a 30% yield of colourless crystalline 3. Analytical
and spectroscopic data for 3 were consistent with the
formation of [Al(SC6H3Me2-2,6)3(OEt2)] rather than
that of the expected product [H2Al(SC6H3Me2-2,6)]n
(Scheme 2). Interestingly, the addition of 3 equiv. of 2,6-
Me2C6H3SH to [AlH3(OEt2)] resulted in the formation
of a mixture of products rather than the isolation of
compound 3.
The X-ray analysis revealed compound 3 to be the
tri(thiophenolato)aluminium-diethyl ether species de-
picted in Fig. 3 (Table 3). The structure, ignoring the
two ethyl groups, has pseudo C3 symmetry about the
Fig. 2. The structure of the [Al(SC6H3Me2-2,6)4]ꢀ anion in 2.
˚
2.254(3) A,
whereas the fourth, to Al-(2), is significantly longer at
S(4), lie in the narrow range 2.250(2)ꢂ
/
OÃ
/
Al direction creating a propeller-like geometry.
Al vector, the structure shown in
Viewed down the OÃ
/
˚
2.275(2) A. Such a lengthening has been seen previously
in the structure of [i-Pr2NH2][Al(SÃt-Bu)4] [3], where it
was associated with the presence of weak NÃ ꢀ ꢀ ꢀ
S ca. 3.38 A. Here in 2 the
Fig. 3 has a L-type conformation, but as the crystal is
racemic the structure contains equal numbers of D and
L forms. The three 2,6-dimethylphenyl ring systems are
oriented approximately orthogonally (778, 828 and 968)
to the S3 plane. The ‘all down’ geometry observed here is
in contrast to the ‘one up, two down’ conformation seen
/
/
H
/
/S
˚
hydrogen bonds with N
NMe2Et nitrogen approaches S(2) at 3.37 A, suggesting
an analogous NÃ S hydrogen bonding interaction.
/
ꢀ ꢀ ꢀ
/
˚
/
H
/
ꢀ ꢀ ꢀ
/
We thus conclude that in the solid state structure of 2
the ‘missing’ proton most probably resides on the
nitrogen of the NMe2Et unit. The geometry at alumi-
nium does not exhibit the flattening observed in 1,
in the related [Al(SC6H2Ã
/
i-Pr3-2,4,6)3(thf)] species [2].
The geometry at aluminium is best described as flattened
tetrahedral, the metal centre being displaced towards the
˚
‘basal’ S3 face, lying only 0.43 A out of this plane in the
though the SÃ
/
AlÃ
/
S angles cover a fairly wide range of
direction of the oxygen atom (a deviation very similar to
that seen in 1). The angles subtended at aluminium are
between 103.79(7)8 [S(4)/S(3)] and 119.45(10)8 [S(1)/
S(3)]. The molecule has superficially non-crystallo-
graphic S4 symmetry, though on closer inspection it is
found that the planes of the four 2,6-dimethylphenyl
rings are inclined by between 498 and 648 to the vector
in the range 97.34(7)ꢂ
three SÃAlÃS angles is 3498. The AlÃ
unexceptional, ranging between 2.227(1) and 2.238(1) A
/
120.81(5)8, and the sum of the
/
/
/
S distances are
˚
˚
O distance is 1.907(2) A). The propeller-like
(the AlÃ
/
bisecting the S(1)Ã
/
AlÃ
/
S(3) angle. Except for the already
geometry results in one of the methyl groups of each 2,6-
dimethylphenyl ring system being directed into the face
discussed weak NÃ
/
H
/
ꢀ ꢀ ꢀ
/S hydrogen bond, there are no
noteworthy packing interactions. Analytical and spec-
troscopic data for 2 were consistent with the formation
of its nearest neighbour aryl ring, the shortest H
˚
distance being 2.78 A. There are no intermolecular
/
ꢀ ꢀ ꢀ
/
p
Table 2
˚
Selected bond lengths (A) and angles (8) for 2
Bond lengths
AlÃ
AlÃ
S(1)Ã
S(3)Ã
/
S(1)
S(3)
2.250(2)
2.254(3)
1.771(6)
1.792(6)
AlÃ
AlÃ
S(2)Ã
S(4)Ã
/
S(2)
S(4)
2.275(2)
2.250(2)
1.790(6)
1.794(7)
/
/
/
C(11)
C(31)
/
C(21)
C(41)
/
/
Bond angles
S(4)Ã
S(1)Ã
S(1)Ã
C(11)Ã
C(31)Ã
/
AlÃ
AlÃ
AlÃ
/
S(1)
S(3)
S(2)
108.28(9)
119.45(10)
104.65(8)
102.5(2)
S(4)Ã
S(4)Ã
S(3)Ã
C(21)Ã
C(41)Ã
/
AlÃ
AlÃ
AlÃ
/
S(3)
S(2)
S(2)
103.79(9)
116.49(9)
104.78(9)
103.7(2)
107.0(2)
/
/
/
/
/
/
/
/
/
S(1)Ã
/
Al
Al
/
S(2)Ã
/
Al
Al
/
S(3)Ã
/
101.9(2)
/
S(4)Ã
/
Scheme 2.

2658
C.J. Carmalt et al. / Polyhedron 22 (2003) 2655ꢂ2660
/
Fig. 3. The molecular structure of 3.
Fig. 4. The structure of the homoleptic, S4-symmetric anion in the
˚
crystals of 4. Selected bond length (A) and angles (8); AlÃ
SÃC(1) 1.784(4), SÃAlÃS(0A) 119.16(6), SÃAlÃS(0B) 104.85(3), C(1)Ã
SÃAl 107.42(12).
/
S 2.2534(9),
/
/
/
/
/
/
/
interactions of note. The formation of 3 is similar to the
isolation of [Al(SÃt-Bu)3(NMe2Et)] (1) from the reac-
/
tion between [AlH3(NMe2Et)] and 1 equiv. of t-BuSH
(Scheme 1). In addition, the 1H and 13C NMR data for 1
and 3 indicate the presence of bound and uncoordinated
ligand (NMe2Et for 1 and Et2O for 3) suggesting that an
exchange process is occurring.
slight flattening of the tetrahedron about the S4 axis
(which bisects the SÃAlÃS(0A) angle), and an AlÃ
distance of 2.253(1) A. This distance is similar to those
seen for the three AlÃS bonds in 2 where the sulfur is not
/
/
/
S
˚
/
involved in intermolecular hydrogen bonding (2.250(2)ꢂ
/
In order to obtain compound 3, the mixture of
LiAlH4 and AlCl3 was stirred for 30 min before the
addition of 2,6-Me2C6H3SH. However, if 2,6-
Me2C6H3SH is added immediately to the slurry of
LiAlH4 and AlCl3 in diethyl ether, colourless crystals
of a new compound [Li(OEt2)3][Al(SC6H3Me2-2,6)4] (4)
are obtained (Scheme 2). The formation of 4 is probably
the result of incomplete reaction of aluminium(III)
chloride with LiAlH4 before the addition of the thiol.
1H/13C NMR data show only the formation of 4 rather
than a mixture of products. A single crystal X-ray
diffraction analysis showed the anion in 4 to be the S4-
symmetric homoleptic complex shown in Fig. 4. The
geometry at aluminium is distorted tetrahedral with
unique angles of 104.85(3)8 and 119.16(6)8, reflecting a
˚
2.254(3) A, vide supra). The [(Et2O)3Li] cation is
disordered. Attempts to prepare compound 4 from the
reaction of LiAlH4 and 4 equiv. of 2,6-Me2C6H3SH
under the same conditions (diethyl ether, room tem-
perature) resulted in decomposition.
3. Summary
The aluminium tris(thiolate) complexes [Al(SÃ
/
t-
Bu)3(NMe2Et)] (1), and [Al(SC6H3Me2-2,6)3(OEt2)] (3)
have been synthesised from the 1:1 reaction of [AlH3(L)]
(Lꢁ
Me2C6H3SH). Compound 1 can be prepared in higher
yields (Â70%) from the 1:3 reaction of [AlH3(NMe2Et)]
/
NMe2Et or Et2O) and RSH (Rꢁ/t-Bu or 2,6-
/
and t-BuSH [3]. These results suggest that [AlH3(L)]
reacts with thiols in a similar manner to alcohols (ROH)
to produce not very well defined species of composition
Table 3
˚
Selected bond lengths (A) and angles (8) for 3
[AlH3ꢀn(ER)n] (EꢁO, S) [14]. The formation of the
/
Bond lengths
aluminium tris(thiolate) complexes also suggests that
compounds of the type [AlH3ꢀn(SR)n] undergo ligand
exchange reactions at ambient temperatures. Two ionic
AlÃ
AlÃ
S(1)Ã
S(3)Ã
/
O
S(2)
1.907(2)
2.238(1)
1.794(3)
1.796(3)
AlÃ
AlÃ
S(2)ÃC(21)
/
S(1)
2.227(1)
2.234(1)
1.797(3)
/
/S(3)
/
C(11)
C(31)
/
/
complexes
containing
the
homoleptic
anion
[Al(SC6H3Me2-2,6)4]ꢀ (compounds 2 and 4) have also
been isolated. All the compounds have been structurally
characterised. We are currently investigating reactions
between AlH3 and thiols under different conditions (e.g.
low temperature), the results of which will be described
in a future publication.
Bond angles
OÃAlÃS(1)
S(1)ÃAlÃ
S(1)ÃAlÃ
C(11)Ã
C(31)Ã
/
/
104.03(7)
112.73(4)
120.81(5)
106.12(9)
107.98(9)
OÃ
OÃ
S(3)Ã
C(21)Ã
/
AlÃ
/
S(3)
102.01(7)
97.34(7)
/
/
S(3)
/
AlÃ
/S(2)
/
/S(2)
/
AlÃ
/
S(2)
Al
115.61(4)
107.03(9)
/
S(1)Ã
/
Al
Al
/
S(2)Ã
/
/
S(3)Ã
/

C.J. Carmalt et al. / Polyhedron 22 (2003) 2655ꢂ
/2660
2659
4. Experimental
in CH2Cl2 (Â
5 cm3) and over a period of days at room
/
temperature colourless crystals of 2 were formed. Anal.
Calc. for C36H48NS4Al: C, 66.52; H, 7.44; N, 2.15.
Found: C, 64.20; H, 6.72; N, 2.35. 1H NMR (CD2Cl2): d
4.1. General and physical measurements
All manipulations were performed under a dry,
oxygen-free dinitrogen atmosphere using standard
Schlenk techniques or in a Mbraun Unilab glove box.
All solvents were distilled from appropriate drying
agents prior to use (sodium/benzophenone for ether)
and AlH3(OEt2) was prepared by literature methods
[15]. [AlH3(NMe2Et)] was supplied by Epichem Ltd. All
other reagents were procured commercially from Al-
drich and used without further purification. Microana-
lytical data were obtained at University College London
(UCL).
1.10 (t, Jꢁ
/
11 Hz, HNCH2CH3), 1.17 (t, Jꢁ11 Hz,
/
NCH2CH3), 2.14 (s, SC6H3(CH3)2-2,6), 2.34 (s,
SC6H3(CH3)2-2,6), 2.45 (s, N(CH3)2), 2.73 (s,
HN(CH3)2), 2.77 (q, Jꢁ
/19 Hz, HNCH2CH3), 3.31 (q,
Jꢁ19 Hz, NCH2CH3), 6.86ꢂ
/
/7.01 (m, SC6H3(CH3)2-
2,6), 7.70 (br, NH). 13C{1H} NMR (CD2Cl2): d 6.0 (s,
NCH2CH3), 9.9 (s, HNCH2CH3), 23.8 (s, SC6H3-
(CH3)2-2,6), 24.1 (s, SC6H3(CH3)2-2,6), 42.7 (s, NCH2-
CH3), 43.2 (s, HNCH2CH3), 51.8 (s, N(CH3)2), 54.0 (s,
HN(CH3)2), 125.2 (s, m-SC6H3(CH3)2-2,6), 126.0 (s, m-
SC6H3(CH3)2-2,6), 127.3 (s, ipso-SC6H3(CH3)2-2,6),
127.9 (s, ipso-SC6H3(CH3)2-2,6), 133.1 (s, p-SC6H3-
(CH3)2-2,6), 136.2 (s, p-SC6H3(CH3)2-2,6), 142.7 (s, o-
SC6H3(CH3)2-2,6)142.8 (s, o-SC6H3(CH3)2-2,6). IR (nu-
jol, cmꢀ1): 3143 m, 1581 m, 1375 s, 1161 m, 1115 m,
1082 m, 1062 m, 1021 m, 988 s, 914 s, 812 m, 764 vs, 720
s, 586 s, 544 s, 469 s, 458 m, 442 w.
1H and 13C NMR spectra were recorded on Bruker
AMX400 spectrometers at UCL. The NMR spectra are
referenced to CDCl3 or CD2Cl2, which was degassed
and dried over molecular sieves prior to use; 1H and 13
C
chemical shifts are reported relative to SiMe4 (0.00
ppm). IR spectra were run on a Shimadzu FTIR-8200
instrument. Melting points were obtained in sealed glass
capillaries under nitrogen and are uncorrected.
4.2.3. [Al(SC6H3Me2-2,6)3(OEt2)] (3)
Following literature routes, 15AlCl3 (0.22 g, 1.60
mmol) was dissolved in diethyl ether (10 cm3) and
added slowly to a stirred slurry of LiAlH4 (0.19 g, 5.0
mmol) in diethyl ether (15 cm3). After stirring for 1 h,
2,6-Me2C6H3SH (0.88 cm3, 6.65 mmol) was added
dropwise and the immediate evolution of hydrogen
was observed. The resulting grey slurry was stirred at
room temperature for 24 h. After filtering through celite
the solvent was reduced in vacuo to ca. 5 cm3 and cooled
4.2. Preparations
4.2.1. [Al(SÃ
/
t-Bu)3(NMe2Et)] (1)
t-BuSH (0.43 cm3, 3.77 mmol) was added dropwise to
a solution of [AlH3(NMe2Et)] (0.5 cm3, 3.77 mmol) in
diethyl ether (20 cm3) at room temperature. The
evolution of hydrogen was observed and the mixture
was stirred at room temperature for 1.5 h. The solution
was reduced in volume to Â
Cooling to ꢀ20 8C for 24 h resulted in the formation of
colourless crystals of 1 (0.19 g, 15% yield based on
aluminium), m.p. 84ꢂ86 8C. Anal. Calc. for
/
5 cm3 under vacuum.
to ꢀ
crystals of 3 formed (1.09 g, 28% yield based on
aluminium, m.p. 103ꢂ104 8C). Anal. Calc. for
C28H37O1S3Al: C, 65.59; H, 7.27. Found C, 65.51; H,
7.41. 1H NMR (CDCl3): d 1.12 (t, Jꢁ
11 Hz, 6H,
O(CH2CH3)2), 1.35 (t, Jꢁ11 Hz, 3H, O(CH2CH3)2),
2.25 (s, 18H, SC6H3(CH3)2-2,6), 3.42 (q, Jꢁ21 Hz, 4H,
O(CH2CH3)2), 4.37 (q, Jꢁ21 Hz, 2H, O(CH2CH3)2),
6.77ꢂ
6.95 (m, 9H, SC6H3(CH3)2-2,6). 13C{1H} NMR
/
20 8C. After 24 h at this temperature colourless
/
/
/
C16H38NS3Al: C, 52.27; H, 10.42; N, 3.81. Found: C,
1
51.38; H, 9.92; N, 3.46. H NMR (CD2Cl2): d 1.12 (t,
/
/
Jꢁ
/
10 Hz, 3H, NCH2CH3), 1.14 (t, Jꢁ
/10 Hz,
/
NCH2CH3), 1.57 (s, 27H, SC(CH3)3), 2.56 (s, 6H,
N(CH3)2), 2.58 (s, N(CH3)2), 3.08 (q, NCH2CH3), 3.22
(q, 2H, NCH2CH3). 13C{1H} NMR (CD2Cl2): d 5.9 (s,
NCH2CH3), 35.1 (s, SC(CH3)3), 41.8 (s, N(CH3)2), 45.2
(s, SC(CH3)3), 50.7 (s, NCH2CH3). IR (nujol, cmꢀ1):
1463 s, 1425 m, 1377 m, 1360 m, 1216 w, 1169 m, 1150
m, 1078 m, 1019 m, 999 m, 915 w, 820 w, 764 m, 582 s,
504 s, 412 w.
/
/
(CDCl3): d 13.4 (s, O(CH2CH3)2), 15.1 (s, O(CH2-
CH3)2), 23.6 (s, SC6H3(CH3)2-2,6), 65.8 (s, O(CH2-
CH3)2), 68.8 (s, O(CH2CH3)2), 125.5 (s, m-SC6H3-
(CH3)2-2,6), 127.5 (s, ipso-SC6H3(CH3)2-2,6), 132.4 (s,
p-SC6H3(CH3)2-2,6), 142.0 (s, o-SC6H3(CH3)2-2,6). IR
(KBr disc, cmꢀ1): 3057 m, 2977 m, 2922 w, 1460 s, 1436
m, 1371 m, 1323 w br, 1262 w, 1188 m, 1162 m, 1149 m,
1088 m, 1051 s, 1009 s, 989 m, 878 s, 831 w, 760 vs, 718 s,
588 m, 528 s, 496 s, 480 s, 413 m.
4.2.2. [HNMe2Et][Al(SC6H3Me2-2,6)4] (2)
2,6-Me2C6H3SH (0.3 cm3, 2.26 mmol) was added
dropwise to a solution of [AlH3(NMe2Et)] (0.3 cm3, 2.26
mmol) in diethyl ether (15 cm3) at room temperature.
Evolution of hydrogen was observed and a white
precipitate formed. The solvent was removed under
vacuum yielding a white powder (0.39 g, 27% yield
based on aluminium). The white powder was dissolved
4.2.4. [Li(OEt2)3][Al(SC6H3Me2-2,6)4] (4)
Compound 4 was prepared using the same procedure
described above for 3, except that 2,6-Me2C6H3SH was
added immediately to the slurry of LiAlH4 and AlCl3.
Colourless crystals of 4 formed from a concentrated

2660
C.J. Carmalt et al. / Polyhedron 22 (2003) 2655ꢂ2660
/
diethyl ether solution at ꢀ
/
20 8C (0.24 g, 10% yield based
Crystal data for 4: [C32H36S4Al][C12H30O3Li]×
/
¯
on aluminium, decomposed without melting below
230 8C). Anal. Calc. for C44H66O3S4LiAl: C, 65.63; H,
8.26. Found C, 63.71; H, 7.51. H NMR (CDCl3): d
C4H10O, Mꢁ
12.186(1), cꢁ17.693(3) A, Vꢁ
symmetry), Dcalc
mmꢀ1, Tꢁ
183 K, colourless tetrahedra; 1242 indepen-
dent measured reflections, F2 refinement, R1ꢁ
0.042,
wR2ꢁ0.114, 1130 independent observed absorption
corrected reflections [jFojꢀ4s(jFoj), 2umax 1288], 224
parameters. The absolute structure of 4 was determined
by a combination of R-factor tests [R1ꢃ ꢁ
0.0417,
R1ꢀ ꢁ
0.0508] and by use of the Flack parameter
[xꢃ ꢁ
0.07(5)]. Disorder was observed in both the
/
879.3, tetragonal, I
/
4 (no. 82), aꢁ
/
3
˚
˚
/
/
2627.3(4) A , Zꢁ
/
2 (S4
1
ꢁ
/
1.111 g cmꢀ3, m (Cu Ka)ꢁ
/2.11
2.00 (t, Jꢁ
SC6H3(CH3)2-2,6), 3.53 (q, Jꢁ
O(CH2CH3)2), 6.86ꢂ6.97 (m, 9H, SC6H3(CH3)2-2,6).
/14 Hz, O(CH2CH3)2), 2.27 (s, 24H,
/
/21 Hz, 4H,
/
/
/
13C{1H} NMR (CDCl3): d 14.8 (s, O(CH2CH3)2), 23.8
(s, SC6H3(CH3)2-2,6), 66.0 (s, O(CH2CH3)2), 125.0 (s,
m-SC6H3(CH3)2-2,6), 127.1 (s, ipso-SC6H3(CH3)2-2,6),
134.8 (s, p-SC6H3(CH3)2-2,6), 142.3 (s, o-SC6H3(CH3)2-
2,6). IR (KBr disc, cmꢀ1): 1583 w, 1303 w, 1257 w, 1161
m, 1092 m, 1051 s, 1022 m, 912 m, 838 w, 798 m, 771 s,
759 m, 587 m, 521 m, 492 m, 468 m, 436 m, 408 m.
/
ꢁ
/
/
/
/
ꢀ
/
included solvent diethyl ether molecule and in those
coordinated to the lithium centre. CCDC 194437.
4.3. X-ray crystallography
5. Supplementary material
Crystals of 1, 3 and 4 were grown from diethyl ether
solutions at ꢀ
CH2Cl2 at room temperature.
Crystal data for 1: C16H38NS3Al, Mꢁ
hombic, Pbca (no. 61), aꢁ11.668(1), bꢁ16.626(1), cꢁ
8, Dcalc 1.121 g
3.45 mmꢀ1, Tꢁ
183 K, colourless
prisms; 3226 independent measured reflections, F2
refinement, R1ꢁ0.034, wR2ꢁ0.076, 2668 independent
observed absorption corrected reflections [jFojꢀ
4s(jFoj), 2umax 1208], 191 parameters. CCDC 194439.
/
20 8C and crystals of 2 were grown from
Supplementary data are available from the CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK on request,
/367.6, orthor-
quoting the deposition numbers CCDC 194436ꢂ
/
194439
/
/
/
(fax: ꢃ44-1223-336033; e-mail: deposit@ccdc.cam.ac.uk
/
3
˚
˚
22.468(2) A, Vꢁ
/
4358.5(5) A , Zꢁ
/
ꢁ
/
or www: http://www.ccdc.cam.ac.uk).
cmꢀ3, m (Cu Ka)ꢁ
/
/
/
/
Acknowledgements
/
ꢁ
/
We thank EPSRC for a studentship (J.D.M.).
4.3.1. Crystal data for 2
C32H36S4Al×C4H12N, Mꢁ
aꢁ11.034(7), bꢁ11.485(2), cꢁ
81.65(1)8, bꢁ74.18(2)8, gꢁ62.92(1)8, Vꢁ
Zꢁ2, Dcalc
1.197 g cmꢀ3, m (Cu Ka)ꢁ2.83 mmꢀ1
Tꢁ183 K, colourless blocks; 5091 independent mea-
sured reflections, F2 refinement, R1ꢁ
0.086, wR2ꢁ
0.232, 3658 independent observed absorption corrected
1208], 379 para-
meters. The somewhat high final value of R is a
reflection of the poor quality of the crystals (including
the presence of significant twinning) with consequent
diffuse diffraction. CCDC 194438.
¯
˚
/
/
650.0, triclinic, P
/
1 (no. 2),
References
/
/
/
16.618(2) A, aꢁ
/
3
˚
1804(1) A ,
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/
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4.3.2. Crystal data for 3
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[11] O. Madelung, R. Poerschke (Eds.), Semiconductor: other than
C28H37OS3Al×
(no. 14), aꢁ15.946(3), bꢁ
bꢁ104.13(1)8, Vꢁ
cmꢀ3, m (Mo Ka)ꢁ
prisms; 5780 independent measured reflections, F2
refinement, R1ꢁ0.048, wR2ꢁ0.105, 4218 independent
observed reflections [jFojꢀ4s(jFoj), 2umax 508], 344
parameters. CCDC 194436.
/
Et2O, Mꢁ
/
586.9, monoclinic, P21/c
˚
/
/
14.182(2), cꢁ
/
14.984(4) A,
4, Dcalc 1.186 g
0.28 mmꢀ1, Tꢁ
183 K, colourless
3
˚
/
/
3286(1) A , Zꢁ
/
ꢁ
/
Group IV Elements and IIIꢂ
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Weinheim, 1997, pp. 216ꢂ319.
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/V Compounds, Verlag, Berlin, 1992.
/
/
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/
/
[14] A. Schlegel, H. Noth, H. Schwenk-Kirchner, Angew. Chem., Int.
¨
Ed. Engl. 36 (1997) 2640.
/
ꢁ
/
[15] H. Noth, H. Suchy, Z. Anorg. Allg. Chem. 358 (1968) 44.
¨