π-spacer-coupled diimidosulfinates

Article abstract of DOI:10.1515/znb-2010-0607

To synthesize ligands that are capable of coordinating two metals, 1,4-dilithiumbenzene and 4,4′-dilithiumbiphenyl were reacted with different sulfurdiimides to give coupled diimidosulfinates. [(THF) ₄Li₂{(NSiMe₃)₂S} ₂biphenyl] (1) and [(THF)_1.5Li₂{(NSiMe ₃)₂S}₂biphenyl]∞ (2) could be isolated and structurally characterized. While 1 forms distinct molecules in the solid state, 2 crystallizes in infinite chains. The lithium complex with a benzene group as spacer could not be isolated due to co-complexed lithium bromide. Subsequent metal exchange reactions with dimethylaluminum chloride afforded [{Me₂Al(N^tBu)₂S}₂biphenyl] (3) and [{Me₂Al(NSiMe₃)₂S}₂(C ₆H₄)] (4).

Full text of DOI:10.1515/znb-2010-0607

π-Spacer-coupled Diimidosulfinates
Thomas Schulz, David-Raphael Dauer, and Dietmar Stalke
Institut fu¨r Anorganische Chemie, Georg-August Universita¨t Go¨ttingen, Tammannstraße 4,
37077 Go¨ttingen, Germany
Reprint requests to Prof. Dr. D. Stalke. Fax: 0551/393459. E-mail: dstalke@chemie.uni-goettingen.de
Z. Naturforsch. 2010, 65b, 711 – 718; received February 9, 2010
To synthesize ligands that are capable of coordinating two metals, 1,4-dilithiumbenzene and
4,4ꢀ-dilithiumbiphenyl were reacted with different sulfurdiimides to give coupled diimidosulfinates.
[(THF)4Li2{(NSiMe3)2S}2biphenyl] (1) and [(THF)1.5Li {(NSiMe3)2S}2biphenyl]∞ (2) could be
isolated and structurally characterized. While 1 forms disti2nct molecules in the solid state, 2 crystal-
lizes in infinite chains. The lithium complex with a benzene group as spacer could not be isolated
due to co-complexed lithium bromide. Subsequent metal exchange reactions with dimethylaluminum
chloride afforded [{Me2Al(NtBu)2S}2biphenyl] (3) and [{Me2Al(NSiMe3)2S}2(C6H4)] (4).
Key words: Sulfur, Imide, Aromatic Spacers, Lithium, Aluminum
Introduction
an organic spacer. Two sulfurdiimides and also
two sulfurtriimides were coupled with a methylene
bridge [27, 28] or with a thiophene, dithiophene or
selenophene bridge [29]. Fueled by these promising
results, in the work presented in this paper we em-
barked to broaden the field of organic spacers (Fig. 1)
and investigated the metal exchange of the coupled
lithium diimidosulfinates.
Since aryl groups are more rigid and therefore tend
to give less intramolecular side reactions when doubly
metalated [30] our choice was to employ dibromo-
benzene and dibromobiphenyl as synthons for organic
spacers. Another advantage of those aryl groups is the
possibility to exploit different regio isomers. By the
use of either 1,4-dibromobenzene and 1,3-dibromo-
benzene or 2,2ꢀ-biphenyl and 4,4ꢀ-dibromobiphenyl
the distance of the coordination sites and hence
the distance between the two metal atoms can be
varied. With this in mind we synthesized, isolated and
Heterobimetallic complexes are known to be excel-
lent catalysts for a variety of reactions [1 – 7]. The main
areas of application are the polymerization of various
alkenes [8 – 10] and the catalytic enhancement of or-
ganic reactions [11 – 13]. Furthermore, oxidation reac-
tions can be facilitated by the use of heterobimetal-
lic catalysts [14, 15]. To combine two metals in one
molecule it is often feasible to use Janus-Head ligands
[16 – 20]. These ligands provide the option to coordi-
nate hard and soft metals [21] by employing two dif-
ferent coordination sites. Since diimidosulfinates are
known to coordinate hard metals like lithium [22 – 24]
but also soft metals like cesium [25] and barium [26]
they are an obvious choice for the design of Janus-
Head ligands. In addition to their flexibility in metal
coordination it is their solubility in nearly all organic
solvents that makes coupled diimidosulfinates a worth-
while synthetic target.
characterized
[(THF)4Li2{(NSiMe3)2S}2biphenyl]
(1), [(THF)1.5Li2{(NSiMe3)2S}2biphenyl]∞ (2) and
[{Me2Al(NtBu)2S}2biphenyl] (3) with biphenyl as a
longer spacer and [{Me2Al(NSiMe3)2S}2(C6H4)] (4)
with benzene for a shorter bridge.
Results and Discussion
Fig. 1. Spacers for the synthesis of coupled diimidosulfinates.
Synthesis of coupled lithium diimidosulfinates
Previous investigations in our group showed that
it is possible to connect two sulfurdiimides through
For the synthesis of the coupled lithium diimido-
sulfinates, 1,4-dibromobenzene, 1,3-dibromobenzene,
c
0932–0776 / 10 / 0600–0711 $ 06.00 ꢀ 2010 Verlag der Zeitschrift fu¨r Naturforschung, Tu¨bingen · http://znaturforsch.com
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
Scheme 1. Synthesis of coupled
lithium diimidosulfinates.
Fig.
2 (color online). Crystal structure of
[(THF)4Li2{(NSiMe3)2S}2biphenyl] (1). Aniso-
tropic displacement parameters are depicted at
the 50 % probability level, and all hydrogen
atoms have been omitted for clarity. Selected
bond lengths and angles are presented in Table 1.
2,2ꢀ-dibromobiphenyl and 4,4ꢀ-dibromobiphenyl were spectra are not free of signals of side products due to
n
t
lithiated twice with BuLi, or with BuLi in the case the uncertain stoichiometry. The crystal structure could
of the dibromobenzene compounds. The reactions of also not be determined because the lithium bromide
2,2ꢀ-dilithiumbiphenyl and 1,3-dilithiumphenyl with tends to crystallize more readily than the lithium di-
the sulfurdiimides did not afford the desired products. imidosulfinate. In spite of these purification problems
The reason for this is probably the insufficient distance the metal exchange from lithium to aluminum (vide
between the lithiated positions. Apparently there is not infra) worked and proved a posteriori that the reac-
enough room for the simultaneous addition of both sul- tion of the lithiated benzene with the sulfurdiimide was
furdiimides. The other spacers reacted readily with the successful.
sulfurdiimides (Scheme 1) and yielded the coupled di-
imidosulfinates.
Structural characterization of
[(THF)4Li2{(NSiMe3)2S}2biphenyl] (1) and
[(THF)1.5Li2{(NSiMe3)2S}2biphenyl]∞ (2)
Unfortunately, [{(THF)2Li(NR)2S}2(C6H4)] could
not be isolated and characterized due to the co-
1 crystallizes at −30◦ in the triclinic space group
complexation with the lithium bromide side prod-
¯
P1 (Fig. 2) with half of the molecule in the asym-
uct generated in the synthesis of 1,4-dilithiumbenzene
from 1,4-dibromobenzene. Several attempts to sepa-
rate the lithium bromide or prevent its formation in
the course of the synthesis failed. It seems that the
twofold lithiated benzene is highly reactive and at-
tacks the formed RBr (R= n-butyl, t-butyl) to give
lithium bromide. The LiBr co-complexation hampers
further experiments since the molecular weight of the
dimetalated species remains unknown, and the amount
of employed 1,4-dilithiumbenzene is difficult to de-
termine. In addition it makes it nearly impossible to
get reliable evidence of the formation of [{(THF)2-
metric unit. In contrast to the diimidosulfinates de-
scribed in the literature, the molecule does not dimer-
ize but accomplishes the favored fourfold coordina-
tion of the lithium atom by coordination of two THF
molecules. Up to now monomeric diimidosulfinates
have only been known with a chelating donor base like
TMEDA [31]. Otherwise only triimidosulfinates or the
S(NtBu)4 anion have been known to crystallize as
2−
monomers when THF is the only donor base present
[32, 33].
When the reaction of 4,4ꢀ-dilithiumbiphenyl with
Li(NR)2S}2(C6H4)] in the NMR experiment since the bis(trimethylsilyl)sulfurdiimide is performed in a
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
713
Fig. 3 (color online). Part of the crystal struc-
ture of [(THF)1.5Li2{(NSiMe3)2S} biphenyl]∞
(2). All hydrogen atoms and the carb2on atoms of
the trimethylsilyl groups have been omitted for
clarity. Anisotropic displacement parameters are
depicted at the 50 % probability level. Selected
bond lengths and angles are presented in Table 1.
Fig. 4 (color online). Part of the pack-
ing plot of [(THF)1.5Li2{(NSiMe3)2S}2-
biphenyl]∞ (2). All hydrogen atoms and
the carbon atoms of the trimethylsilyl
groups have been omitted for clarity.
˚
Table 1. Selected bond lengths (A) and angles (deg) for 1, 2,
coordination geometries at the metal atoms depend-
ing on the conformation at the Li2N2 four-membered
rings. While the mode of connectivity in the first
of these units provides a co-linear orientation of the
biphenyl substituents, the second one induces an al-
most perpendicular twisted kink (99.4◦) in the poly-
meric chain. This kink is caused by a donor base-
free four-fold N-coordinated lithium atom (Li3) which
leads to an overall stair-like arrangement. The corre-
sponding lithium atom at the hollow of the knee is only
in a trigonal planar coordination by two nitrogen atoms
of different diimidosulfinate ligands and a single THF
molecule. In the unit leading to a co-linear arrange-
ment both lithium atoms (Li1 and Li2) exhibit a dis-
torted tetrahedral coordination by three nitrogen atoms
and an oxygen atom of a THF donor base each. Al-
ternating Li–N contacts provide the linkages along the
chain.
3 and 4.
1
2
3
4
S-N (av.)
S-C (av.)
Li1-N
1.601(1) 1.560(4) S-N1
1.810(2) 1.793(4) S-N2
2.040(3) 1.989(8) Al-C
2.082(3) 2.426(8)
2.055(8)
1.644(2) 1.622(2)
1.648(2) 1.625(2)
1.957(3) 1.958(3)
1.980(3) 1.959(3)
Li2-N
Li3-N
2.019(8) Al-N1
2.199(8) Al-N2
1.984(5)
1.908(2) 1.929(2)
1.915(2) 1.936(2)
Li1-O
Li2-O
1.941(3) 1.973(8) S-C
1.947(4)
1.796(2) 1.801(3)
1.89(1)
N-S1-N 91.17(9) 94.94(12)
N-S-N (av.) 104.02(7) 105.89(18) C-S-N 105.71(9) 105.05(11)
106.30(9) 105.36(11)
C-S-N (av.) 102.99(8) 103.22(20) N-Al-N 75.90(7) 76.49(10)
THF/hexane mixture, and the saturated solution is
afterwards stored at r. t., the compound [(THF)1.5Li2-
{(NSiMe3)2S}2biphenyl]∞ (2) is obtained. In contrast
Both structural motifs are known for lithium diimi-
to 1, it is a coordination polymer (Figs. 3 and 4) as dosulfinates, and the bond lengths and angles are in
already expected from known lithium diimidosulfinate the normal range expected for S–N and Li–N distances
structures [24, 26, 34]. Interestingly, 2 shows different [25, 34, 35]. Comparing those in 2 and in the com-
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
Scheme 2. Synthesis of 3 and 4.
plex [(THF)Li(NSiMe3)2SPh]2 [35], which also ex- at −78◦ (Scheme 2). The reactions proceeded
hibits a tetrahedrally LiN3(THF) coordinated lithium smoothly and afforded [{Me2Al(NtBu)2S}2biphenyl]
atom, shows the N–S–N backbone to be very simi- (3) and [{Me2Al(NSiMe3)2S}2(C6H4)] (4). Both com-
lar. The Li–N distances show only slight differences pounds could be crystallized and structurally charac-
˚
( 0.03 A see Table 1).
terized. Although only half an equivalent of Me2AlCl
was employed to get mixed metal complexes, both
lithium atoms got replaced by the dimethylaluminum
moiety. In 4 the amount of the used lithium diimido-
sulfinate could not be determined unequivocally due
to the LiBr co-complexation discussed earlier, but ob-
viously the exchange reaction with dimethylaluminum
chloride is not selective enough to substitute only one
lithium atom.
The addition of the dilithiated spacers and the fol-
lowing metal exchange with Me2AlCl were performed
with the di-tert-butyl-sulfurdiimide as well as with the
bis(trimethylsilyl)sulfurdiimide. Regarding the lithium
compounds, only the trimethylsilyl derivates had been
crystallized and characterized. The reactions with
the bis(tert-butyl)sulfurdiimide only afforded powders
that gave no satisfactory NMR spectra. Neverthe-
less, the subsequent metal exchange with Me2AlCl
afforded 3.
One of the two Li2N2 motifs exhibited by 2 can
also be observed in [(Et2O){Li(NSiMe3)2SPh}2] [35].
Li2 shows the same Li–N and Li–O distances although
[(Et2O){Li(NSiMe3)2SPh}2] crystallizes with Et2O as
the donor base instead of THF. The comparison of
˚
˚
the Li3–N distances in 2 (2.20 A / 1.98 A) and in
˚
˚
[(Et2O){Li(NSiMe3)2SPh}2] (2.24 A / 1.99 A) shows
more distinct differences [35]. The change of the do-
nating solvent from Et2O to THF seems not to be
the reason for the differences since the bond lengths
around Li2 are similar in both structures. So they must
be induced by the packing of the coordination poly-
mer 2.
The inspection of the three different lithium atom
environments present in 2 shows the Li–N and Li–O
distances around Li2 to be the shortest. Since Li2 ex-
hibits only three instead of four coordinative bonds,
it needs to compensate for the lack in charge density
by closer contacts to the electron-rich neighbors. Es-
Structural characterization of [{Me2Al(NtBu)2S}2bi-
phenyl] (3) and [{Me2Al(NSiMe3)2S}2(C6H4)] (4)
˚
pecially the Li–O distance is 0.06 A shorter than in 1
and even 0.09 A shorter than the Li1–O bond in 2. Fi-
˚
nally the fact that both compounds can be crystallized
at only slightly different conditions shows that 1 and 2
must be rather close in energy. From the comparison of
known dimeric diimidosulfinates it seems clear that 2
exhibits the most favorable coordination of the lithium
atoms. The different coordination in 1 may be due to
the formation of hydrogen bonds. While in 2 only in-
tramolecular hydrogen bonds can be found, in 1 the
stability of the solid-state structure is enhanced by one
intermolecular hydrogen bond per molecule.
[{Me2Al(NtBu)2S}2biphenyl] (3) and [{Me2Al-
(NSiMe3)2S}2(C6H4)] (4) show almost the same struc-
tural motif (Figs. 5 and 6). The N–S–N planes exhibit
a similar arrangement relative to the aromatic spacer
planes (120.0◦ for 3 and 125.1◦ for 4), and in both
structures the two sulfurdiimido moieties are arranged
trans relative to each other. Both aluminum atoms
show a tetrahedral coordination geometry with the N–
Al–N angle clearly smaller than the ideal tetrahedral
angle. All the other angles around the metal atom are
slightly larger.
Synthesis of the dimethylaluminum diimidosulfinates
For the metal exchange the lithium diimidosulfi-
All bond lengths and angles are similar and in the
nates were treated with half an equivalent of Me2AlCl same range as in other known aluminum di- and tri-
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
715
Fig. 5 (color online). Crystal structure of [{Me2-
Al(NtBu)2S}2biphenyl] (3). Anisotropic dis-
placement parameters are depicted at the 50 %
probability level, and all hydrogen atoms have
been omitted for clarity. Selected bond lengths
and angles are presented in Table 1.
Conclusion
In this paper we report the syntheses and struc-
tures of four bis(sulfurdiimides) linked by arene spac-
ers. Our experiments showed that the starting mate-
rials 1,4-dibromobenzene, 1,3-dibromobenzene, 2,2ꢀ-
biphenyl and 4,4ꢀ-dibromobiphenyl can easily be
twofold lithiated. Presumably due to steric hindrance
only 1,4-dilithiumbenzene and 4,4ꢀ-dilithiumbiphenyl
react cleanly with sulfurdiimides to give the coupled
diimidosulfinates 1 – 4. The reactions show aryl groups
to be perfect candidates for the connection of two
chelating ligands. The twofold lithiation proceeds al-
most quantitatively and without side products. Al-
though the addition reactions worked well and yielded
1 and 2, the following metal exchange reactions where
not selective enough to allow substitution of only one
of the two lithium sites. Therefore, better suited metal
fragments have to be found with reduced reactivity
and increased selectivity to accomplish the intended
synthesis of heterobimetallic complexes. Further metal
exchange reactions are currently under investigation.
A promising candidate for further studies is 9,10-
dibromo-anthracene.
Fig. 6 (color online). Crystal structure of [{Me2Al-
(NSiMe3)2S}2Ph] (4). Anisotropic displacement parameters
are depicted at the 50 % probability level, and all hydrogen
atoms have been omitted for clarity. Selected bond lengths
and angles are presented in Table 1.
imido sulfinates [32, 36]. Only marginal differences
can be detected in the S–N and Al–N bond lengths
(Table 1). In 3 the S–N bond lengths are elongated by
˚
0.02 A while the Al–N bond lengths are shortened by
the same amount.
When comparing 3 and 4 with the lithium diimido-
sulfinates the only noticeable differences that can be
Experimental Section
˚
spotted are in the M–N bond lengths (av. Li: 2.04 A
All experiments were carried out either in an atmosphere
of purified dry nitrogen or argon by using modified Schlenk
techniques or in an argon drybox. The glassware was dried
for several hours at 120 ◦C, assembled hot, and cooled under
vacuum. The solvents were freshly distilled from potassium
prior to use and degassed. The reactants were commercially
available or synthesized according to published procedures
S(NtBu)2 [37].
All NMR spectra were recorded on Bruker Avance 500
spectrometers. The chemical shifts δ are given in ppm with
positive values for low-field shifts relative to tetramethylsi-
lane as external standard.
˚
vs. av. Al: 1.92 A), and the N–S–N angles are also
different (av. Li: 103◦ vs. av. Al: 93◦). As the metal-
nitrogen bonds are shortened the sulfur-metal distances
get smaller, too. To prevent both electropositive atoms
from getting too close, the N–S–N angle is widened.
The S–N bond lengths are slightly elongated in 3 and 4
˚
˚
(av. 1.64 and 1.62 A) compared to 1 and 2 (av. 1.60 A)
probably because the aluminum atom acquires more
from the negative charge at the nitrogen atom resulting
in smaller electrostatic interactions between the sulfur
and the nitrogen atom.
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
Elemental analyses were performed by the Mikroanalyti- der reduced pressure. After 2 d storage at 4◦ colorless crys-
sches Labor des Instituts fu¨r Anorganische Chemie der Uni- tals suitable for X-ray diffraction were obtained. Yield (%):
versita¨t Go¨ttingen with an Elementar Vario EL3 apparatus. 3.79 g, 5.0 mmol, 76 %. – Elemental analysis in % found
The determined values deviate more than usual from the cal- (calcd.): C 61.85 (62.50), H 9.61 (9.18), N 8.90 (9.11),
culated ones, as the substances are highly sensitive to oxygen S 10.20 (10.43). – 1H NMR (500 MHz, [D8]THF): δ = 7.98
and moisture.
(d, 3JHH = 8.2 Hz, 4 H, meta), 7.80 (d, 3JHH = 8.4 Hz, 4 H,
ortho), 1.36 (s, 36 H, C(CH3)3), −0.58 – −0.68 (br, 12 H,
Mass spectra were recorded with the electron ionization
method (EI-MS: 70 eV) on a Finnigan MAT 95 spectrome-
ter. The mass-to-charge ratios (m/z) of the fragment ions are
based on the molecular mass of the isotopes with the high-
est natural abundance. The molecular ion peak M is defined
as the compound without coordinated solvent. Some spec-
1
Al(CH3)2). – 13C{ H} NMR (125 MHz, [D8]THF): δ =
150.92 (s, ipso), 144.09 (s, para), 128.96 (s, ortho), 127.50
(s, meta), 53.29 (s, C(CH3)3), 31.95 (s, C(CH3)3), −4.79 (s,
Al(CH3)2).
EI-MS: m/z (%) = 502 (11) [M–2 AlMe2+H]+, 429
tra were unspecific as the ionic character and the reactivity (13) [M–2 AlMe2–NtBu]+, 360 (30) [M–2 AlMe2–2
of the synthesized compounds made the measurement diffi- NtBu+H]+, 289 (10) [M–2 AlMe2–3 NtBu+2 H]+, 57 (100)
cult. Due to the reactivity and solubility of the compounds, [AlMe2/tBu]+, 41 (50) [C3H5]+.
no electron spray ionization (ESI-MS) or fast atom bombard-
ment (FAB-MS) mass spectra could be recorded.
Synthesis of bis-dimethylaluminum-benzene-1,4-bis-
trimethylsilyldiimidosulfinate (4)
Synthesis of the dilithium-biphenyl-4,4ꢀ-bis-trimethylsilyl-
diimidosulfinates (1) and (2)
To a solution of 4.7 g (20 mmol) 1,4-dibromobenzene
in 30 mL toluene 24 mL of a 1.67 M solution of BuLi
t
A suspension of 3.1 g (10 mmol) 4,4ꢀ-dibromobiphenyl
in 15 mL Et2O was treated with 11.2 mL (20 mmol) of a
1.79 M solution of nBuLi at −78 ◦C. After stirring for 2 h the
resulting colorless solid was filtered and washed with cold
hexane.
(40 mmol) was added. After stirring for 2 h the resulting
light-yellow solid was filtered and washed with cold Et2O.
4.2 g (16 mmol) 1,4-dilithiumbenzene was suspended in
20 mL of Et2O, and 6.6 g (32 mmol) of S(NSiMe3)2 was
◦
added at −78 C. After stirring over night the light-orange
4.0 g (8.7 mmol) 4,4ꢀ-dilithiumbiphenyl was suspended
in THF (for 2 a THF/hexane mixture was used), and 3.6 g
precipitate was filtered and washed with cold Et2O.
A solution of 9.0 g (12.3 mmol) dilithium-benzene-1,4-
◦
(17.4 mmol) of S(NSiMe3)2 was added at −78 C. After
bis-trimethylsilyldiimido-sulfinate in 15 mL THF was re-
◦
stirring over night, part of the solvent was removed under acted with 1.2 mL (12.3 mmol) Me2AlCl at −78 C. Af-
reduced pressure. After 2 d storage at 4◦ colorless crystals
suitable for X-ray diffraction were obtained. For 2 the high-
est peaks in the mass spectrum and the signals of the NMR
spectrum where the same as for 1. The elemental analysis for
2 gave poor results. Yield (%): 6.16 g, 7.1 mmol, 71 % (re-
ferring to 4,4ꢀ-dibromobiphenyl). – Elemental analysis in %
found (calcd.): C 55.47 (55.38), H 9.47 (8.72), N 6.69 (6.50),
S 7.79 (7.39). – 1H NMR (500 MHz, [D8]THF): δ = 7.77
ter stirring over night, part of the solvent was removed
under reduced pressure. The remaining solid was filtered
and the solution stored in the refrigerator at 4 ◦C. After
2 d storage colorless crystals suitable for X-ray diffraction
were obtained. Yield (%): 5.67 g, 9.4 mmol, 47 % (referring
to 1,4-dibromobenzene). – Elemental analysis in % found
(calcd.): C 43.33 (43.81), H 9.01 (8.69), N 9.45 (9.29),
S 10.09 (10.63). – 1H NMR (500 MHz, [D8]THF): δ =
8.16 – 7.98 (m, 4 H), −0.03 (br, 36 H, Si(CH3)3), −0.61 –
3
3
(d, JHH = 8.0 Hz, 4 H, ortho), 7.50 (d, JHH = 8.0 Hz,
4 H, meta), 3.62 ppm (m, 8 H, OCH2CH2), 1.77 (m, 8 H,
1
−0.72 (br, 12 H, Al(CH3)2). – 13C{ H} NMR (125 MHz,
OCH2CH2), 0.11 (s, 36 H, Si(CH3)3). – 13C{ H} NMR
1
[D8]THF): δ = 155.78 (s, ipso), 127.16 (br, meta, ortho),
3.20 (s, Si(CH3)3), −4.71 (s, Al(CH3)2). – EI-MS: m/z (%) =
(125 MHz, [D8]THF): δ = 150.81 (s, ipso), 143.54 (s, para),
127.81 (s, ortho), 126.99 (s, meta), 67.4 (OCH2CH2), 25.3 588 (61) [M–Me]+, 574 (22) [M–2 Me+H]+, 530 (19) [M–
SiMe3]+, 73 (18) [SiMe3]+, 57 (100) [AlMe2]+.
(OCH2CH2), 1.11 (s, Si(CH3)3). – EI-MS: m/z (%) = 565
(12) [M–2 Li+H]+, 464 (21) [M–2 Li–NSiMe3–CH3+H]+,
392 (100) [M–2 Li–2 NSiMe3+H]+, 287 (25) [M–2 Li–
S(NSiMe3)2–SiMe3+H]+, 73 (26) [SiMe3]+.
X-Ray structure determination
The data for 1 – 4 (Table 2) were collected from shock-
cooled crystals at 100 K (1, 2 and 4) or 170 K (3) [38, 39]
on Bruker SMART-APEX II diffractometers with D8 go-
niometers. For 1 – 3 a Bruker TXS-Mo rotating anode was
Synthesis of bis-dimethylaluminum-biphenyl-4,4ꢀ-bis-
di tbutyl-diimidosulfinate (3)
A solution of 5.3 g (6.6 mmol) 1 in 15 mL THF was used as X-ray source, for 4 an Incoatec microfocus source
◦
reacted with 0.6 mL (6.5 mmol) Me2AlCl at −78 C. Af- was utilized [40]. All diffractometers were equipped with
ter stirring over night, part of the solvent was removed un- a low-temperature device and used monochromated MoKα
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T. Schulz et al. · π-Spacer-coupled Diimidosulfinates
717
Table 2. Crystal structure data for 1 – 4.
1
2
3
4
Formula
C40H76Li2N4
O4S2Si4
867.41
C60H112Li4N8
O3S4Si8
1374.30
764287
0.2 × 0.1 × 0.1
orthorhombic
Pbcn
13.4045(13)
18.8417(16)
33.228(3)
90
C40H72Al2
N4O2S2
759.10
764286
0.4 × 0.2 × 0.2
monoclinic
P21/c
9.0151(13)
15.890(2)
16.808(3)
90
102.658(3)
90
2349.3(6)
2
1.07
0.2
828
−11 ≤ h ≤ +10
0 ≤ k ≤ +19
0 ≤ l ≤ +20
26.04
53732
4630
C22H52Al2N4
S2Si4
603.12
Mr
CCDC no.
764284
764285
Crystal size, mm3
Crystal system
Space group
0.35 × 0.2 × 0.1
0.15 × 0.15 × 0.1
orthorhombic
Pccn
15.7678(11)
16.5892(11)
14.3223(9)
90
90
90
3746.4(4)
4
1.07
0.3
1304
−18 ≤ h ≤ +18
−19 ≤ k ≤ +19
−16 ≤ l ≤ +17
25.34
21854
3431
0.0503
triclinic
¯
P1
˚
a, A
10.1713(16)
10.426(3)
13.924(3)
80.687(4)
68.710(6)
68.492(5)
1279.4(5)
1
˚
b, A
˚
c, A
α, deg
β, deg
90
90
γ, deg
3
˚
V, A
8392.3(13)
4
1.09
0.3
2960
−16 ≤ h ≤ +16
−22 ≤ k ≤ +22
−36 ≤ l ≤ +40
25.46
56409
7750
Z
Dcalcd, g cm−3
µ(MoKα ), cm−1
F(000), e
hkl range
1.13
0.2 mm−1
470
−11 ≤ h ≤ +12
−12 ≤ k ≤ +12
0 ≤ l ≤ +16
25.35
31830
4687
−1
˚
((sinθ)/λ)max, A
Refl. measured
Refl. unique
Rint
0.0221
0.1079
0.0327
Param. refined
349
455
241
224
R(F)/ wR(F2)a (all refl.)
0.0417 / 0.0946
1.043
0.46 / 0.30
0.0990 / 0.1959
1.167
0.58 / −0.34
0.0561 / 0.1465
1.049
0.49 / −0.46
0.0671 / 0.1084
1.023
0.38 / −0.38
GoF (F2)b
∆ρfin (max / min), e A
−3
˚
R1 = ΣꢁFo|− |Fc|/Σ|Fo|, wR2 = [Σw(Fo − Fc2)2/Σw(Fo2)2]1/2, w = [σ2(Fo2)+(AP)2+BP]−1, where P = (Max(Fo2, 0)+2Fc2)/3 and A and
a
2
B are constants adjusted by the program; b GoF = S = [Σw(Fo − Fc2)2/(nobs − nparam)]1/2, where nobs is the number of data and nparam the
2
number of refined parameters.
˚
radiation, λ = 0.71073 A, with mirror optics as monochro- bond lengths restraints and isotropic displacement parameter
mator. The data of 1 – 4 were integrated with SAINT [41], restraints [44].
and an empirical absorption correction (SADABS) was ap-
CCDC 764284–764287 contain the supplementary crys-
plied [42]. All structures were solved by Direct Methods tallographic data for this paper. These data can be obtained
(SHELXS-97) [43] and refined by full-matrix least-squares free of charge from The Cambridge Crystallographic Data
methods against F2 (SHELXL-97) [44]. All non-hydrogen Centre via www.ccdc.cam.ac.uk/data request/cif.
atoms were refined with anisotropic displacement param-
Acknowledgement
eters. The hydrogen atoms were refined isotropically on
calculated positions using a riding model with their Uiso
values constrained to 1.5 times the Ueq of their pivot
atoms for terminal sp3 carbon atoms and 1.2 times for all
other carbon atoms. Disordered moieties were refined using
The authors like to thank the DFG priority programme
1178, the Georg-August Universita¨t Go¨ttingen, the Land
Niedersachsen and the Volkswagenstiftung for providing su-
perb X-ray facilities.
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