Syntheses and structures of lithiated sulfones Li[CR(R′)SO2Ph] - C versus O bound lithium. [{Li{CH(Me)SO2Ph}(thf)}∞] - The structure of a C-bound derivative

Article abstract of DOI:10.1016/j.jorganchem.2005.12.048

Sulfones RCH(R′)SO₂Ph were reacted with n-BuLi in thf/n-hexane (R/R′ = H/Me, Me/Et, H/CH₂Ph) and toluene/n-hexane (R/R′ = Me/Ph) yielding under deprotonation Li[CR(R′)SO₂Ph] which reacted with Me₃SiCl and n-Bu

Full text of DOI:10.1016/j.jorganchem.2005.12.048

Journal of Organometallic Chemistry 691 (2006) 2358–2367
www.elsevier.com/locate/jorganchem
Syntheses and structures of lithiated sulfones Li[CR(R0)SO2Ph] –
C versus O bound lithium. [{Li{CH(Me)SO2Ph}(thf)} ] –
1
The structure of a C-bound derivative
*
Matthias Linnert, Clemens Bruhn, Christoph Wagner, Dirk Steinborn
Institut fu¨r Anorganische Chemie der Martin-Luther-Universita¨t Halle-Wittenberg, Kurt-Mothes-Straße 2, D-06120 Halle (Saale), Germany
Received 31 August 2005; received in revised form 19 December 2005; accepted 23 December 2005
Available online 20 February 2006
Abstract
Sulfones RCH(R0)SO2Ph were reacted with n-BuLi in thf/n-hexane (R/R0 = H/Me, Me/Et, H/CH2Ph) and toluene/n-hexane
(R/R0 = Me/Ph) yielding under deprotonation Li[CR(R0)SO2Ph] which reacted with Me3SiCl and n-Bu3SnCl forming the requisite tri-
methylsilyl and tri(n-butyl)tin substituted derivatives R030E-CðRÞR0SO2Ph ðR030E ¼ Me3Si; n-Bu3SnÞ. Performing the reactions of
RCH(R0)SO2Ph with n-BuLi in n-hexane (instead of thf/n-hexane) and toluene/n-hexane, respectively, resulted in the precipitation of
the organo lithium compounds Li[CR(R0)SO2Ph] (1–4) which were isolated as strongly moisture-sensitive yellow powders in essentially
1
quantitative yields. Their identities were confirmed by H and 13C NMR spectroscopic measurements in thf-d8. Solutions of each 1, 3,
and 4 in thf/n-hexane and thf/n-pentane afforded crystals of each [{Li{CH(Me)SO2Ph}(thf)} ] (1a), [{Li{CH(CH2Ph)SO2Ph}(thf)} ]
1
1
(3a), and [{Li{CMe(Ph)SO2Ph}(thf)2}2] (4a), respectively, whose structures were determined by single-crystal X-ray crystallography.
The compounds 1a and 3a crystallize in 1D polymeric ladder-like structures. The strands of 1a are built-up by eight-membered
˚
Li2C2S2O2 rings having direct Li–C bonding interactions (Li–C 2.215(5) A). The donor set of Li is completed by three oxygen atoms,
one from the thf ligand and two from SO2 groups of neighboring Li{CH(Me)SO2Ph}(thf) entities. The strands of 3a are built-up of alter-
nating Li2S2O4 eight- and Li2O2 four-membered rings. Each lithium atom is coordinated to three oxygen atoms, two from
O2S(Ph)CHCH2Ph groups and one from thf oxygen atom. There is no Li–C bonding. Compound 4a crystallizes in dimers consisting
of eight-membered Li2S2O4 rings in which the two lithium atoms are bridged by two O2S(Ph)CHMePh groups. The coordination sphere
of lithium is completed by two oxygen atoms of the thf ligands.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: a-Sulfonyl functionalized alkyl carbanions; Lithiated alkyl phenyl sulfones; Oxygen versus carbon coordination; Structures of organo lithium
compounds
1. Introduction
nated. Some derivatives with chiral carbanionic centers
exhibit a relatively high conformational stability [4,5].
Thus, such carbanions have not only received experimental
interest but also considerable attention from the theoretical
point of view. Structurally characterized compounds
Li[CR(R0)SO2R00] (R, R0 = alkyl, aryl, H; R00 = alkyl, aryl)
contain in the most cases tmeda or diglyme coligands and
were found to be dimeric in the solid state [4]. The central
structural units in these dimers are eight-membered
Li2S2O4 rings in which the SO2 groups bridge the two lith-
ium atoms. There are Li–O bonds only and no Li–C bonds.
The lone pairs of electrons on the ‘‘free’’ carbanions were
Lithium-coordinated a-sulfonyl functionalized alkyl
carbanions are widely used in organic synthesis as versatile
building blocks for a wide range of organic compounds [1].
Since the carbanions are dipole stabilized [2], the a-C–H
bonds in the requisite sulfones are acidic (cf. pKa(CH3-
SO2Ph) = 29.0 in DMSO [3]) and can be easily deproto-
*
Corresponding author. Tel.: +49 345 5525620; fax: +49 345 5527028.
E-mail address: dirk.steinborn@chemie.uni-halle.de (D. Steinborn).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.12.048

M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
2359
found to be bisecting the O–S–O angle. In a single case, the
crystal structure of thf adduct was obtained,
Performing the reactions of RCH(R0)SO2Ph with n-
BuLi in n-hexane instead of a thf/n-hexane mixture
(Scheme 1, a) resulted in the precipitation of the organo
lithium compounds Li[CR(R0)SO2Ph] (1–3) which were
isolated as strongly moisture-sensitive yellow powders in
essentially quantitative yields. MeCH(Ph)SO2Ph was found
not to react with n-BuLi in hexane obviously due to its
insolubility in n-hexane. In toluene/n-hexane MeCH(Ph)-
SO2Ph reacted with n-BuLi yielding 4 in 89% yield.
a
[{{Li(thf)2}{CPh(CH2Ph)SO2CF3}}2] [6], which was also
found to be dimeric as described above. On the other hand,
in the case of a-sulfanyl functionalized lithiumalkyls
LiCH2SR the structures are strongly dependent on the
coligand. Tmeda adducts are dimeric with six-membered
Li2C2S2 or four-membered Li2C2 rings [7] whereas the thf
adducts were found to be dimeric or polymeric [8].
Here, we describe the synthesis of solvate-free com-
pounds Li[CR(R0)SO2Ph] (R/R0 = H/Me, Me/Et, H/
CH2Ph, Me/Ph) from which we prepared the tetrahydrofu-
ran adducts. Furthermore, we succeeded to obtain well-
shaped crystals and single-crystal X-ray investigations
showed both an usual dimeric structure (R/R0 = Me/Ph)
and 1D polymeric structures (R/R0 = H/Me, H/CH2Ph),
one of which (H/Me) has an unusual Li–C bond.
1
Selected H and 13C NMR spectroscopic data of the lith-
ium compounds 1–4 in thf-d8 solutions are given in Table
1. Comparison with the corresponding data of the sulfones
demonstrates that lithiation gives rise to highfield shifts of
the a-carbon resonances by 8.8–13.7 ppm. In complexes 1
and 3 the a-hydrogen resonances are highfield shifted by
1.41 and 1.15 ppm, respectively.
2.2. Structures of a-lithiated alkyl phenyl sulfones
2. Results and discussion
In the case of 1 (R/R0 = H/Me), 3 (R/R0 = H/CH2Ph)
and 4 (R/R0 = Me/Ph) from thf/n-hexane (1, 4) and thf/
n-pentane (3) solutions, respectively, precipitated well
shaped crystals (1a, 3a, 4a) that proved to be suitable for
single-crystal X-ray diffraction measurements (Scheme 1,
d–f). Compounds 1a and 3a were obtained by dissolution
of the solvate-free compounds 1 and 3, respectively, in
thf and precipitation with n-hexane/n-pentane. Analo-
gously, crystals of 4a were obtained, but those of better
2.1. Syntheses and characterization
It is well known that alkyl phenyl sulfones and their
derivatives can be easily deprotonated yielding a-(phen-
ylsulfonyl) substituted carbanions. Consequently, reactions
of RCH(R0)SO2Ph with n-BuLi in thf/n-hexane at ꢀ78 ꢁC
resulted in the formation of the lithium-coordinated a-sul-
fonyl functionalized alkyl carbanions 1–4 (Scheme 1, a).
Their formation could be unambigously proven by reac-
tions with Me3SiCl yielding the requisite trimethylsilyl
substituted derivatives 5–8 in isolated yields between 90
and 95% (Scheme 1, b). Analogous reactions with the less
reactive n-Bu3SnCl resulted in the formation of tri(n-
butyl)tin substituted derivatives 9–11, respectively, in yields
between 60 and 85% (Scheme 1, c). MeCH(Ph)SO2Ph did
not react in this way in thf/n-hexane but the reaction in tol-
uene/n-hexane resulted in the formation of 12 (yield: 49%).
The identities of the silyl and tin compounds 5–12 have
been unequovically established by 1H, 13C, and 119Sn
NMR spectroscopic measurements (see Section 3).
Table 1
Selected chemical shifts of the lithiated sulfones Li[CR(R0)SO2Ph] (1–4) in
thf-d8
a
R/R0
a-CRR0
a-CHRR0
b
dH
dC
dH
dC
1
2
3
4
H/Me
Me/Et
H/CH2Ph
Me/Ph
1.70
–
2.17
–
39.2
47.8
44.9
57.6
3.11
2.91
3.32
4.20
50.5
61.5
57.4
66.4
a
In HCR(R0)SO2Ph for comparison.
For R = H.
b
d
RCH(R´)SO2Ph
n-BuLi
[{Li{CH(Me)SO2Ph}(thf)} ]
∞
1a
a
Me3SiCl
Me3SiCR(R´)SO2Ph
b
e
5 - 8
[{Li{CH(CH2Ph)SO2Ph}(thf)} ]
Li[CR(R´)SO2Ph]
∞
1 - 4
3a
n-Bu3SnCl
n-Bu3SnCR(R´)SO2Ph
c
9 - 12
f
[{Li{CMe(Ph)SO2Ph}(thf)2}2]
R/R´
4a
H/Me
Me/Et
H/CH2Ph
Me/Ph
1, 5, 9
2, 6, 10
3, 7, 11
4, 8, 12
Scheme 1.

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M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
˚
quality crystallized directly from the reaction mixture
PhCH(Me)SO2Ph/n-BuLi. In contrast to the powdery lith-
ium compounds 1, 3 and 4, the complexes 1a and 3a crys-
tallize with one molecule of thf per lithium and 4a with two
molecules of thf per lithium.
between Li and C1 is 2.215(5) A. The donor set of Li is
completed by three oxygen atoms, one (O3) from the thf
ligand and two (O100, O20) from SO2 groups of the neigh-
boring Li{CH(Me)SO2Ph}(thf) entities. The angles around
C1 (Li–C1–C2, Li–C1–S, S–C1–C2) are between 103.9(2)ꢁ
and 115.7(2)ꢁ. Thus, the C1 atom is best described as sp3
hybridized. The C1–S conformation was found to be stag-
gered and the Li–C1 vector is directed along the acute
bisector of the O1–S–O2 angle as exhibited by the two tor-
sional angles O1–S–C1–Li ꢀ61.2(2)ꢁ and O2–S–C1–Li
68.5(2)ꢁ. Thus, 1a may be stabilized by a negative hyper-
conjugation nC1–rꢁSC3 (torsional angle: C3–S–C1–Li
ꢀ176.5(2)ꢁ) between the anionic lone pair orbital at the
C1 and the orbitals of the S–C3 backbone.
2.2.1. Solid state structure of
[{Li{CH(Me)SO2Ph}(thf)} ] (1)
1
Compound 1a crystallizes in a 1D polymeric ladder-like
structure which is shown in Fig. 1. Selected bond lengths
and angles are given in Table 2. The smallest distances
between non-hydrogen atoms between the strands
˚
(>3.1 A) show that there are no unusual interstrand inter-
actions. The strands extend along the crystallographic
a-axis and are built up by eight-membered Li2C2S2O2 cen-
trosymmetric rings. The marked feature of the structure of
1a is a direct Li–C bonding interaction; the distance
2.2.2. Solid state structure of
[{Li{CH(CH2Ph)SO2Ph}(thf)} ] (3a)
1
The 1D polymeric solid state structure of [{Li{CH-
(CH2Ph)SO2Ph}(thf)} ] (3a) is shown in Fig. 2. Selected
1
bond lengths and angles are given in Table 3. Along the
crystallographic b-axis the crystal is threaded by strands
built-up of alternating eight- and four-membered rings.
There are no unusual interstrand interactions; the smallest
˚
distance between non-hydrogen atoms is >3.5 A. The
a
b
c
a
b
Fig. 1. [{Li{CH(Me)SO2Ph}(thf)} ] (1a): Front (a) and side view (b) of
1
the solid-state structure and structural formula (c). Hydrogen atoms were
omitted for clarity and in the side view ‘b’ also the phenyl groups and thf
ligands. From the disordered thf C atoms only the major occupied
positions (71(1)%) are shown.
Table 2
˚
Selected interatomic distances (A) and angles (ꢁ) in [{Li{CH(Me)-
SO2Ph}(thf)} ] (1a)
1
Li–C1
Li–O100
Li–O20
Li–O3
C1–C2
C1–S
C3–S
S–O1
S–O2
2.215(5)
1.922(5)
1.903(5)
2.023(5)
1.503(4)
1.656(3)
1.790(3)
1.448(2)
1.449(2)
Li–C1–C2
Li–C1–S
S–C1–C2
O100–Li–C1
O20–Li–C1
O3–Li–C1
O100–Li–O20
O1–S–O2
103.9(2)
111.4(2)
115.7(2)
115.2(2)
123.8(2)
100.9(2)
109.9(2)
115.5(1)
c
Fig. 2. [{Li{CH(CH2Ph)SO2Ph}(thf)} ] (3a): Front (a) and side view (b)
1
of the solid-state structure and structural formula (c). In ‘a’ hydrogen
atoms of the phenyl substituents and of the thf ligands were omitted for
clarity. In the side view ‘b’ phenyl groups and thf ligands are not shown.

M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
2361
Table 3
˚
Selected interatomic distances (A) and angles (ꢁ) in [{Li{CH(CH2Ph)-
SO2Ph}(thf)} ] (3a)
1
Li–O1
Li–O200
Li–O20
Li–O3
Liꢂ ꢂ ꢂLi0
C1–C2
C1–S
C9–S
S–O1
S–O2
1.883(4)
1.975(5)
1.982(4)
1.936(4)
2.859(8)
1.515(4)
1.608(3)
1.812(2)
1.461(2)
1.480(2)
O1–Li–O200
O1–Li–O20
O1–Li–O3
O20–Li–O200
Li–O20–Li0
S–C1–C2
C1–S–O1
C1–S–O2
O1–S–O2
117.5(2)
119.6(2)
106.9(2)
87.5(2)
92.5(2)
119.9(2)
112.9(1)
109.8(1)
114.8(1)
a
b
strands exhibit crystallographically imposed inversion sym-
metry; the eight- and four-memebered rings are centrosym-
metric. In the Li2S2O4 eight-membered rings the two
lithium atoms are bridged by two O2S(Ph)CHCH2Ph
groups. One oxygen atom (O2) of each of these SO2 groups
bridges two Li atoms (Li–O–Li) and builds up the Li2O2
four-membered rings. The Li–O1 bond is considerably
shorter than the Li–l-O2 bonds (1.883(4) versus 1.975(5)/
Fig. 3. [{Li{CMe(Ph)SO2Ph}(thf)2}2] (4a): Solid-state structure (a) and
structural formula (b). Hydrogen atoms of the thf ligands were omitted for
clarity.
˚
1.982(4) A). As expected, the S@O bond to the bridging
Table 4
oxygen atom is considerably longer than that to the non-
˚
Selected interatomic distances (A) and angles (ꢁ) in [{Li{CMe(Ph)-
˚
bridging oxygen atom (1.480(2) versus 1.461(2) A). Due
SO2Ph}(thf)2}2] (4a)a
to the inversion symmetry the Li2O2 rings are planar.
The Li2S2O4 rings exhibit approximately a chair conforma-
tion [9] with the Li/Li00 and O2/O20 atoms in the plane. The
coordination sphere of the lithium atoms is completed by
coordination of one thf molecule, thus exhibiting a LiO4
donor set. There is no Li–C bonding; the distance between
Li–O1
Li–O20
Li–O3
Li–O4
C1–S
C1–C2
C9–S
S–O1
S–O2
a
1.890(8)/1.920(8)
1.897(8)/1.950(9)
1.949(8)/1.929(8)
1.928(9)/1.966(8)
1.670(5)/1.659(5)
1.503(7)/1.527(7)
1.783(5)/1.791(4)
1.456(4)/1.469(3)
1.460(3)/1.464(3)
O1–Li–O20
O3–Li–O4
O1–S–O2
C2–C1–C3
S–C1–C2
S–C1–C3
114.8(4)/112.6(3)
106.3(4)/103.5(3)
115.6(2)/116.3(2)
119.7(5)/119.6(4)
115.0(4)/116.6(4)
123.3(3)/123.1(3)
˚
Li and the carbanionic C1 atom amounts to 4.238(5) A. In
accordance with that, the S–C1–C2 angle is 119.9(2)ꢁ indi-
cating that the C1 atom is best described as sp2 hybridized.
The values of the two crystallographically independent molecules are
separated by a slash.
2.2.3. Solid state structure of
[{Li{CMe(Ph)SO2Ph}(thf)2}2] (4a)
Compound4acrystallizesindimericmolecules[{Li{CMe-
(Ph)SO2Ph}(thf)2}2] having crystallographically imposed
inversion symmetry. The unit cell contains two symmetri-
cally independent dimers that are very similar in their struc-
tures. One of them is shown in Fig. 3, selected bond lengths
and angles are given in Table 4. The central structural unit
of the dimeric molecule is a centrosymmetric eight-mem-
bered Li2S2O4 ring in which the two lithium atoms are
bridged by two O2S(Ph)CMePh groups. The Li2S2O4 ring
adopts a chair conformation with Li/Li0 and O2/O20 in the
plane. The coordination sphere of lithium is completed by
two oxygen atoms of thf ligands. Again, the primary donor
set of lithium consists of four oxygen atoms. There are no
Liꢂ ꢂ ꢂC contacts; the distance of lithium to the carbanionic
and C2–C1–C3 range from 115.0(4)ꢁ/116.6(4)ꢁ to
123.3(3)ꢁ/123.1(3)ꢁ. Thus, the carbanionic C1 atom can be
described as sp2 hybridized with the lone electron pair per-
pendicular to the C1,C2,C3,S1 plane. Since this plane is
coplanar with the plane of the phenyl group C3,. . .,C8
(interplanar angle: 5.0(3)ꢁ/7.8(3)ꢁ), a conjugative interaction
between the lone pair and the p*-orbital of the phenyl ring
may stabilize the carbanion, as was previously found for ben-
zyl anions [10]. In accordance with this, the C1–C3 bond is
˚
relatively short (1.446(7)/1.448(7) A) compared to @C–Car
(conjugated) bonds (median 1.470, lower/upper quartile
1.463/1.480, n = 37, n – number of observations) [11]. Fur-
thermore, the lone electron pair is approximately periplanar
to the S–Ph bond thus allowing a stabilizing hyperconjuga-
tive nC1–rꢁSPh interaction. This is typical for a-sulfonyl carba-
nions [4,12–14].
1
˚
a-C atom (C1) is 3.93(1)/3.80(1) A. As expected, the car-
banionic C1 atom is essentially planar (sum of angles:
358.0ꢁ/359.3ꢁ; distance of C1 from the C2,C3,S1 plane:
˚
0.127(5)/0.074(5) A) and the angles S1–C1–C2, S1–C1–C3,
2.3. Computational results
1
Quantum chemical calculations on the DFT level of the-
Here and the following the values for the two symmetrically indepen-
ory of Li[CH(Me)SO2Ph] (13) have been performed to gain
dent molecules are separated by a slash.

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M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
Table 5
further insight into the unusual [LiO3C] coordination mode
of the lithiated sulfone 1a. Geometry optimizations without
any symmetry restrictions led to two different equilibrium
structures for 13. One structure (13a) exhibits a Li coordi-
nation at the anionic carbon atom and at one oxygen atom
of the sulfonyl group (coordination mode: j2C,O). In the
other structure (13b) the lithium atom was found to be
coordinated through two sulfonyl oxygen atoms (coordina-
tion mode: j2O,O0). To complete the ligand sphere of Li,
geometry optimizations without any symmetry restrictions
of the solvated compound Li[CH(Me)SO2Ph] Æ 2Me2O
(13 Æ 2Me2O) were also performed. Even for 13 Æ 2Me2O
two equilibrium structures were found showing an
analogous coordination of the lithium atom as described
before with two additional coordinated Me2O molecules.
Thus, in both compounds Li adopts a tetrahedral coordi-
nation with three O atoms and one C atom (13a Æ 2Me2O)
and with four O atoms (13b Æ 2Me2O), respectively. The
molecular structures of these two compounds are shown
in Fig. 4. Molecular structures of 13a and 13b are not
shown; they are essentially the same as 13a Æ 2Me2O/
13b Æ 2Me2O but without the two Me2O molecules. Selected
geometrical parameters for all four lithiated sulfones are
given in Table 5.
˚
Calculated distances (A) and angles (ꢁ) for lithiated sulfones Li[CH(Me)-
SO2Ph] (coordination mode: j2C,O (13a); j2O,O0 (13b)) and their
dimethyl ether adducts Li[CH(Me)SO2Ph] Æ 2Me2O 13a Æ 2Me2O and
13b Æ 2Me2O, respectively
13a
13a Æ 2Me2O
13b
13b Æ 2Me2O
Li–O1
Li–O2
Li–C1
S–C1
S–O1
S–O2
S–C3
1.855
(3.290)
2.109
1.737
1.526
1.474
1.815
1.982
(3.249)
2.259
1.712
1.515
1.483
1.822
1.888
1.885
(3.528)
1.641
1.526
1.530
1.832
2.012
2.013
(3.588)
1.657
1.512
1.516
1.832
S–C1–C2
116.1
117.1
102.3
111.4
116.9
117.0
103.8
110.8
120.2
107.1
111.6
112.8
81.3
119.0
109.7
111.2
112.0
75.9
O1–S–O2
O1–S–C1
O2–S–C1
O1–Li–O2
O1–Li–C1
Li–O3/Li–O4
O3–Li–O4
79.6
73.4
1.977/1.953
108.4
1.932/1.962
112.3
rules [15], the Li–O bonds are longer in 13a Æ 2Me2O/
13b Æ 2Me2O than in 13a/13b (1.982–2.013 A versus
1.855–1.888 A). The same holds for the Li–C distances
(2.259 A in 13a Æ 2Me2O versus 2.109 A in 13a). Further-
more, the coordination of the carbanionic center to lithium
gives rise to a substantial elongation of the S–C1 bond
(1.737/1.712 A versus 1.641/1.657 A). Although the coordi-
nation modes of Li in 1a (experimental values taken from
the solid-state structure), where Li is coordinated to the
anionic C atom and to three O atoms (from coordinated
thf and intermolecularly from two sulfonyl O atoms), and
in 13a Æ 2Me2O (calculated values in the gas phase), where
Li is coordinated to the anionic C atom and to three O
atoms (from two coordinated Me2O and intramolecularly
from one sulfonyl O atom), are different, the Li–C dis-
˚
˚
˚
˚
Coordination of a sulfonyl oxygen atom to lithium gives
˚
rise to an elongation of the S–O bond (1.512–1.526 A ver-
˚
˚
˚
sus 1.474/1.483 A). As expected, these bonds are longer in
the compounds 13a/13b (C.N.(Li) = 2) than in 13a Æ
˚
2Me2O/13b Æ 2Me2O (C.N.(Li) = 4): 1.526–1.530 A versus
˚
1.512–1.516 A. As expected from Gutmann’s bond length
˚
˚
tances (2.259 A in 13a Æ 2Me2O; 2.215(5) A in 1a) agree
well. The calculated value for the S–C1 bond in
˚
˚
13a Æ 2Me2O (1.712 A) was found to be slightly longer than
that in 1a (1.656(3) A).
In both structures with Li–C bonds (13a and 13a Æ
2Me2O) the anionic C atom is strongly pyramidalized
(sum of angles at C1: 334.7ꢁ/337.6ꢁ). The pyramidalization
of the C atom in the two compounds with exclusively Li–O
contacts, 13b and 13b Æ 2Me2O, was found to be less (sum
of angles at C1: 351.6ꢁ/347.4ꢁ). In all four structures there
is a staggered Ca–S conformation. In 13b and 13b Æ 2Me2O
the lone pair at the C atom is gauche to both oxygen atoms.
Thus, a negative hyperconjugation ðnC–rꢁSPhÞ between the
anionic lone pair at Ca and the orbitals of the S–Ph bond
seems to be of major importance for the carbanion stabil-
ization [16–18]. In 13a and 13a Æ 2Me2O the torsional
angles C3–S–C1–Li (ꢀ134.9/ ꢀ 143.7ꢁ) point to reduced
negative hyperconjugation. Accordingly, the C3–S bonds
a
b
˚
in 13a/13a Æ 2Me2O are shorter (1.815/1.822 A) than in
Fig. 4. Calculated structures of Li[CH(Me)SO2Ph] Æ 2Me2O along with
the numbering schemes. (a) 13a Æ 2Me2O. (b) 13b Æ 2Me2O. The structures
of 13a and 13b are essentially the same but without coordinated Me2O;
their numbering schemes are analogous.
˚
13b/13b Æ 2Me2O (1.832/1.832 A).
The compounds where the Li is bound via C and O to
the deprotonated sulfone (13a and 13a Æ 2Me2O) are

M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
2363
energetically more stable than those where the Li is bound
through two sulfonyl O atoms (13b and 13b Æ 2Me2O). As
expected, the energy difference is larger for the compounds
where Li has a coordination number 2 (DE(13a/13b) =
5.7 kcal/mol and 5.0 kcal/mol ZPE corrected) than for
the compounds where Li is tetracoordinated (DE-(13a Æ
2Me2O/13b Æ 2Me2O) = 2.8 kcal/mol and 2.5 kcal/mol
ZPE corrected). Quantum chemical calculations of
Li[CH2SO2Me] gave an analogous result. The structure in
which the Li is associated with one O atom and the anionic
C atom was found to be energetically more stable than the
structure in which the Li is associated with two O atoms
[17,19].
derivative 14 that has the typical Li2S2O4 ring with an addi-
tional Li–C bond. These Li–C bonds are considerably
˚
longer than that in 1a (2.44(1) versus 2.215(5) A) [23]. Fur-
thermore, in the hexameric structure of the dilithiated sul-
fone Li2[C(SiMe3)SO2Ph] (15) [(15)6 Æ Li2O Æ (thf)10] Li–C
˚
distances between 2.18 and 3.08 A were found [24]. In gen-
˚
eral, the Li–C distance in 1a (2.215(5) A) is in the range of
Li–Csp3 distances in ‘‘terminally bonded’’ organolithium
compounds [25] as shown by the comparison with the sul-
˚
fanyl derivatives [{Li(CH2SPh)(tmeda)}2] (2.131(4) A) [7]
and [Li(CH2SPh)(pmdta)] (pmdta = N,N,N0,N00,N00-pen-
˚
tamethyldiethylenetriamine) (2.146(5)/2.20(1) A) [26].
Ph
Ph
Ph
2.4. Conclusion
S
O
O
O
a-Lithiated sulfones Li[CR(R0)SO2R00] (I) have been
found to crystallize typically as dimers in the solid state
without the formation of Li–C bonds. Thus, with tmeda
[5,20,21], diglyme [12,22], and thf [6] as co-ligands eight-
membered Li2S2O4 rings were formed having strong Li–O
bonds. In these compounds Li exhibits LiO2N2 (formula
Ia), LiO5 (formula Ib) and LiO4 (formula Ic) primary
donor sets. The strongly binding tridentate pmdta co-
ligand gave rise to the formation of a monomeric com-
pound where the Li is bound only to one oxygen atom of
the sulfonyl group (Li donor set: LiON3) [13].
O
O
Li
Li
O
O
S
O
Ph Ph
Ph
14
The Li–C1 coordination does not give rise to an unusual
length of the Ca–S bond as a comparison of the C1–S bond
in 1a (1.656(3) A) with those of 3a and 4a (1.608(3)–
˚
˚
1.670(5) A) exhibits. Regardless of whether the lithium
atom is coordinated to sulfonyl oxygen atoms (3a, 4a) or
additionally to the a-carbon atom (1a) the bonds between
sulfur and the a-carbon atoms are significantly shortened
R'
R''
L
R
˚
(1.608(3)–1.670(5) A) compared to S–C bonds in non-lithi-
S
a
Me2N
NMe2
O
Li
O
O
Li
O
˚
ated alkyl phenyl sulfones (median: 1.778 A; lower/upper
L
L
˚
quartile: 1.764/1.790 A; n = 94 [11]). Such bond shortening
MeO
(thf)2
O
OMe
b
c
is also observed in other lithiated sulfones (1.608(6)–
S
˚
R''
R'
1.683(2) A [5,6,12,13,20–22]) and is mostly due to electro-
R
static effects (the attraction between the negatively charged
anionic C atom and the positively charged S atom) [14].
Furthermore, in 1a, 3a, and 4a the S–O bonds are elon-
I
˚
gated (1.448(2)–1.480(2) A) compared with those in non-
In this work, we succeeded to obtain the solvate-free
lithiated sulfones Li[CR(R0)SO2Ph] (1–4) and by crystalli-
zation from thf/n-hexane or thf/n-pentane the tetrahydro-
furan adducts in well-shaped crystals (see Scheme 1, d–f).
Compound 4a (R/R0 = Me/Ph) crystallizes with two mole-
cules of thf and is a dimeric type Ic compound. The less-
solvated compounds 1a and 3a (one molecule thf per Li)
exhibited 1D polymeric structures that are unprecedented
so far. As in 4a, the structural motif in 3a consists of
Li2S2O4 eight-membered rings with lithium in an LiO4
environment. The loss of thf is compensated for by the
coordination of an oxygen atom from a neighboring
Li2S2O4 ring.
˚
lithiated sulfones (median: 1.437 A; lower/upper quartile:
˚
1.431/1.442 A; n = 316 [11]). This can be discussed in terms
of the electrostatic effect of the carbanion neighbored by
the S atom [14] and the Li coordination to the O atoms.
Overall, the structures of lithiated sulfones presented in
this work are a further confirmation that tetrahydrofuran
adducts of functionalized organolithium compounds exhi-
bit a much greater structural diversity than those with
tmeda or other chelating coligands.
3. Experimental
The marked structural feature of compound 1a is the
Li–C bond. Thus, the solid-state structure of 1a is formally
built-up from (thf)Li–CH(Me)SO2Ph in which the coordi-
nation sphere of lithium is completed (LiO3C) by oxygen
coordination from neighboring units. The only other lithi-
ated sulfone having a Li–C bond is the dimeric cyclopropyl
3.1. General considerations
All reactions and manipulations were carried out under
purified argon using standard Schlenk techniques except
the manipulations of organotin and organosilicon com-
pounds. n-Pentane, n-hexane and thf-d8 were dried with

2364
M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
LiAlH4 and thf was distilled from sodium benzophenone
ketyl. NMR spectra were recorded on Varian Gemini 200,
Gemini 2000, and Unity 500 spectrometers using the protio
impurities and the 13C resonances of the deuterated solvents
Si(CH3)3), 2.97–3.00 (m, 2H, CHCH2), 3.08–3.14 (m, 1H,
CHCH2), 6.72–6.77/7.02–7.05/7.32–7.47/7.69–7.74 (m/m/
m/m, 10H, o-H/m-H/p-H, Ph). 13C NMR (50 MHz,
CDCl3): d ꢀ0.8 (s, Si(CH3)3), 32.3 (s, CHCH2), 57.4 (s,
CHCH2), 126.3 (s, p-C Ph), 127.8/128.1/128.3/128.8 (s/s/
s/s, o-C/m-C, Ph + SO2Ph), 132.7 (s, p-C, SO2Ph), 138.5/
141.1 (s/s, i-C, Ph + SO2Ph).
1
as references for H and 13C NMR spectroscopy, respec-
tively. d(119Sn) is relative to external SnMe4 in C6D6. The
preparative centrifugal thin layer chromatography was
made by using a Chromatotron (Harrison Research).
3.2.4. Me3SiCMe(Ph)SO2Ph (8)
3.2. General procedure for metalation of RCH(R0)SO2Ph
(R/R0 = H/Me, Me/Et, H/CH2Ph, Me/Ph) and subsequent
reaction with Me3SiCl/n-Bu3SnCl
Purification by recrystallization from diethyl ether.
Yield: 2.90 g (91%). Anal. Calc. for C17H22SO2Si (318.51):
C, 64.11; H, 6.96; S, 10.07. Found: C, 63.96; H, 6.75; S,
10.36%. 1H NMR (400 MHz, CDCl3): d 0.27 (s, 9H,
Si(CH3)3), 1.61 (s, 3H, CCH3), 7.20–7.26/7.38–7.45 (m/m,
10H, o-H/m-H/p-H, 2 · Ph). 13C NMR (100 MHz, CDCl3):
d ꢀ0.8 (s, Si(CH3)3), 18.1 (s, CCH3), 61.6 (s, SiCCH3(Ph)),
127.2 (s, p-C, Ph), 127.8/127.9/128.3/129.2 (s/s/s/s, o-C/m-
C, Ph + SO2Ph), 132.6 (s, p-C, SO2Ph), 136.1/136.9 (s/s,
i-C, Ph + SO2Ph).
At ꢀ78 ꢁC to a stirred solution of RCH(R0)SO2Ph
(10.0 mmol) in thf (15 ml) a solution of n-BuLi in n-hexane
(10.0 mmol, 1.5 M) was added dropwise. After stirring for
15 min at ꢀ78 ꢁC the mixture was warmed to room temper-
ature and stirred for 2 h. Me3SiCl (10.0 mmol) or n-Bu3SnCl
(10.0 mmol) was added at ꢀ78 ꢁC by a syringe, and the mix-
ture was stirred for 18 h at room temperature. The reaction
mixture was hydrolized with distilled water (20 ml) and
extracted with ether (2 · 30 ml). The combined organic lay-
ers were dried with Na2SO4. After the solvents were removed
in vacuo, the residue was purified as described below.
3.2.5. n-Bu3SnCH(Me)SO2Ph (9)
Purification by preparative centrifugal thin layer chroma-
tography using n-pentane/diethyl ether for eluation. Yield:
3.90 g (85%). Anal. Calc. for C20H36SO2Sn (459.27): C,
52.30; H, 7.90; S, 6.98. Found: C, 52.96; H, 7.84; S, 7.33%.
1H NMR (400 MHz, CDCl3): d 0.90 (t, 9H, d-CH3, Bu),
3.2.1. Me3SiCH(Me)SO2Ph (5)
Purification by preparative centrifugal thin layer chro-
matography using n-pentane/diethyl ether for eluation.
Yield: 2.30 g (95%). Anal. Calc. for C11H18SO2Si
(242.41): C, 54.50; H, 7.48; S, 13.23. Found: C, 55.08; H,
1.14–1.19 (m, 6H, a-CH2, Bu), 1.31–1.38 (m, 6H, c-CH2,
Bu), 1.52–1.59 (m, 6H, b-CH2, Bu), 1.25 (d, JH,H
3
=
3
7.26 Hz, 3H, Bu3SnCH(CH3)), 2.83 (q, JH,H = 7.26 Hz,
1H, Bu3SnCH(Me)), 7.46–7.56/7.80–7.82 (m/m, 5H, Ph).
13C NMR (100 MHz, CDCl3): d 13.7 (s, C4, Bu), 27.3
1
7.41; S, 13.10%. H NMR (400 MHz, CDCl3): d 0.23 (s,
3
9H, Si(CH3)3), 1.09 (d, JH,H = 7.47 Hz, 3H, CH3), 2.60
3
2
(s + d, JSn,C = 62.6 Hz, C3, Bu), 28.9 (s + d, JSn,C
=
3
(q, JH,H = 7.26 Hz, 1H, CH), 7.44–7.47/7.78–7.80 (m/m,
1
19.6 Hz, C2, Bu), 11.0 (s + d, JSn,C = 329.2 Hz, C1, Bu),
4H, o-H/m-H, Ph), 7.48–7.52 (m, 1H, p-H, Ph). 13C
NMR (100 MHz, CDCl3): d ꢀ1.5 (s, Si(CH3)3), 11.5 (s,
CH3), 50.5 (s, CH), 127.7/128.7 (s/s, o-C/m-C), 132.6 (s,
p-C), 140.0 (s, i-C).
1
12.9 (s, Bu3SnCH(CH3)), 48.0 (s + d, JSn,C = 136.9 Hz,
Bu3SnCH(Me)), 127.7/128.7 (s/s, o-C/m-C), 132.3 (s, p-C),
139.9 (s, i-C). 119Sn NMR (186 MHz, CDCl3): d 5.6.
3.2.6. n-Bu3SnCMe(Et)SO2Ph (10)
3.2.2. Me3SiCMe(Et)SO2Ph (6)
Purification by preparative centrifugal thin layer chroma-
tography using n-pentane/diethyl ether for eluation. Yield:
3.40 g (70%). Anal. Calc. for C22H40SO2Sn (487.33): C,
54.22; H, 8.27; S, 6.58. Found: C, 54.64; H, 8.38; S, 6.85%.
1H NMR (500 MHz, CDCl3): d 0.89 (t, 9H, d-CH3, Bu),
1.11–1.21/1.24–1.42/1.49–1.62/1.82–2.00 (m/m/m/m, 26H,
CH2, Bu + Me + Et), 7.41–7.57/7.69–7.75 (m/m, 5H, Ph).
13C NMR (100 MHz, CDCl3): d 13.6 (s, C4, Bu), 27.4
Purification by preparative centrifugal thin layer
chromatography using n-pentane/diethyl ether for elua-
tion. Yield: 2.43 g (90%). Anal. Calc. for C13H22SO2Si
(270.46): C, 57.73; H, 8.20; S, 11.86. Found: C, 58.05; H,
1
8.20; S, 11.71%. H NMR (400 MHz, CDCl3): d 0.26 (s,
3
9H, Si(CH3)3), 0.86 (t, JH,H = 7.58 Hz, 3H, CH2CH3),
1.17 (s, 3H, CCH3), 1.39/1.71 (m/m, JH,H = 7.5 Hz/
7.5 Hz, 1H/1H, CH2CH3), 7.43–7.48/7.73–7.76 (m/m, 4H,
o-H/m-H, Ph), 7.51–7.56 (m, 1H, p-H, Ph). 13C NMR
(100 MHz, CDCl3): d ꢀ0.5 (s, Si(CH3)3), 10.5 (s, CH2CH3),
18.5 (s, CCH3), 27.9 (s, CH2CH3), 57.2 (s, Me3SiC), 128.5/
129.9 (s/s, o-C/m-C), 132.9 (s, p-C), 137.2 (s, i-C).
3
2
(s + d, JSn,C = 67.0 Hz, C3, Bu), 28.9 (s + d, JSn,C
=
1
18.4 Hz, C2, Bu), 12.1 (s + d, JSn,C = 325.6 Hz, C1, Bu),
12.0 (s, CH2CH3), 19.4 (s, CCH3), 28.7 (s, CH2CH3), 62.7
1
(s + d, JSn,C = 178.7 Hz, Bu3SnCMe(Et)), 128.3/129.5 (s/s,
o-C/m-C), 132.4 (s, p-C), 136.1 (s, i-C). 119Sn NMR
(186 MHz, CDCl3): d 12.1.
3.2.3. Me3SiCH(CH2Ph)SO2Ph (7)
Purification by recrystallization from isopropanol. Yield:
2.90 g (91%). Anal. Calc. for C17H22SO2Si (318.51): C,
64.11; H, 6.96; S, 10.07. Found: C, 64.43; H, 7.17; S,
10.52%. 1H NMR (200 MHz, CDCl3): d 0.26 (s, 9H,
3.2.7. n-Bu3SnCH(CH2Ph)SO2Ph (11)
Purification by preparative centrifugal thin layer chro-
matography using n-pentane/diethyl ether for eluation.

M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
2365
Yield: 3.20 g (60%). Anal. Calc. for C26H40SO2Sn (535.37):
C, 58.33; H, 7.53; S, 5.99. Found: C, 58.53; H, 7.45; S,
5.85%. 1H NMR (500 MHz, CDCl3): d 0.88 (t, 9H, d-
CH3, Bu), 0.99–1.13 (m, 6H, a-CH2, Bu), 1.26–1.33 (m,
6H, c-CH2, Bu), 1.41–1.54 (m, 6H, b-CH2, Bu), 2.98–3.06
(m, 2H, CHCH2), 3.28–3.31 (m, 1H, CHCH2), 6.85–6.87/
thf-d8): d 16.3 (s, CCH3(Ph)), 57.6 (s, CCH3(Ph)), 115.0
(s, p ꢀ C, Ph) 119.7 (s, p ꢀ C, SO2Ph) 125.7/127.3/128.5/
129.1 (s/s/s/s, o-C/m-C, Ph + SO2Ph), 145.3 (s, i-C,Ph),
150.8 (s, i-C, SO2Ph).
3.5. Synthesis of n-Bu3SnCMe(Ph)SO2Ph (12)
7.05–7.12/7.38–7.41/7.45–7.48/7.76–7.78
(m/m/m/m/m,
10H, o-H/m-H/p-H, 2 · Ph). 13C NMR (125 MHz,
At room temperature, to a stirred solution of 4 in tolu-
ene/n-hexane prepared as described above, n-Bu3SnCl
(10.0 mmol) was added by a syringe. Then, the reaction
mixture was stirred for 18 h at room temperature. After-
wards, water (20 ml) was added. The phases were separated
and the aqueous phase was extracted with diethyl ether
(2 · 30 ml). The combined organic phases were dried
(Na2SO4) and after the removal of the solvents in vacuo
volatile impurities were removed by heating the residue
up to 200 ꢁC at 0.01 Torr. Yield: 2.60 g (49%). Anal. Calc.
for C26H40SO2Sn (535.37): C, 58.33; H, 7.53; S, 5.99.
3
CDCl3): d 13.6 (s, C4, Bu), 27.2 (s + d, JSn,C = 66.7 Hz,
2
C3, Bu), 28.7 (s + d, JSn,C = 19.3 Hz, C2, Bu), 11.5
1
(s + d, JSn,C = 336.9 Hz, C1, Bu), 33.8 (s, CHCH2Ph),
1
55.0 (s + d, JSn,C = 128.4 Hz, Bu3SnCH(CH2Ph)), 126.5
(s, p-C, Ph), 127.6/128.1/128.4/128.7 (s/s/s/s, o-C/m-C,
Ph + SO2Ph), 132.3 (s, p-C, SO2Ph), 138.3/140.7 (s/s, i-C,
Ph + SO2Ph). 119Sn NMR (186 MHz, CDCl3): d 3.4.
3.3. Synthesis of Li[CH(Me)SO2Ph] (1),
Li[CMe(Et)SO2Ph] (2) and Li[CH(CH2Ph)SO2Ph] (3)
1
Found: C, 59.01; H, 7.80; S, 5.83%. H NMR (400 MHz,
At room temperature to a stirred solution of n-BuLi in
n-hexane (10.0 mmol, 0.375 M) RCH(R0)SO2Ph (R/
R0 = H/Me, Me/Et, H/CH2Ph) (10.0 mmol) was added
dropwise. Stirring the reaction mixture for 30 min resulted
in precipitation of 1, 2, and 3, respectively, as yellow pow-
ders, which were filtered off, washed with n-pentane
(2 · 10 ml) and dried in vacuo. Compound 1: Yield: 1.76 g
CDCl3): d 0.83 (t, 9H, d-CH3, Bu), 1.10–1.17 (m, 6H, a-
CH2, Bu), 1.22–1.31 (m, 6H, c-CH2, Bu), 1.40–1.49 (m,
6H, b-CH2, Bu), 1.68 (s + d, JSn,H = 39.0 Hz, 3H, CH3),
3
7.11–7.26/7.28–7.30/7.34–7.40/7.49–7.52 (m/m/m/m, 10H,
o-H/m-H/p-H, Ph + SO2Ph). 13C NMR (100 MHz,
3
CDCl3): d 13.5 (s, C4, Bu), 27.2 (s + d, JSn,C = 66.7 Hz,
2
C3, Bu), 28.7 (s + d, JSn,C = 18.4 Hz, C2, Bu), 12.8
1
(100%). 1H NMR (200 MHz, thf-d8):
d
1.39 (d,
(s + d, JSn,C = 323.4 Hz, C1, Bu), 18.9 (s, CH3), 64.2
3JH,H = 5.81 Hz, 3H, CH3), 1.70 (broad, 1H, CH), 7.19–
7.29/7.71–7.74 (m, 5H, Ph). 13C NMR (50 MHz, thf-d8):
d 11.8 (s, CH3), 39.2 (s, CH), 126.2/128.4 (s/s, p-C/m-C/
(s + d, JSn,C = 154.5 Hz, Bu3SnCCH3(Ph)), 126.6 (s, p-C,
1
Ph), 127.8/127.9/128.1/128.9 (s/s/s/s, o-C/m-C, Ph +
SO2Ph), 132.2 (s, p-C, SO2Ph), 136.1/137.6 (s/s, i-C,
Ph + SO2Ph). 119Sn NMR (186 MHz, CDCl3): d 29.2.
o-C,Ph). Compound 2: Yield: 1.92 g (94%). 1H NMR
3
(400 MHz, thf-d8):
d
0.93 (t, JH,H = 7.24 Hz, 3H,
CH2CH3), 1.62 (broad, 3H, CH3), 2.04 (broad, 2H,
CH2CH3), 7.12 (broad, 1H, p-H,Ph), 7.23/7.62 (broad/
broad, 4H, o-H/m-H,Ph). 13C NMR (100 MHz, thf-d8): d
15.2/16.2 (s/s, 2 · CH3), 26.7 (s, CH2CH3), 47.8 (s,
CMe(Et)), 127.2 (s, p-C), 125.3/128.2 (s/s, o-C/m-C),
151.4 (s, i-C). Compound 3: Yield: 2.51 g (100%). 1H
NMR (400 MHz, thf-d8): d 2.17 (broad, 1H, CHCH2),
3.38 (broad, 2H, CHCH2), 6.90–7.42/7.85–7.86 (m/m,
10H, Ph). 13C NMR (100 MHz, thf-d8): d 33.9 (s, CHCH2),
44.9 (s, CHCH2), 125.0 (s, p-C, Ph), 125.8/128.1/128.9/
129.0 (s/s/s/s, o-C/m-C/p-C, Ph + SO2Ph), 147.4/154.1
(s/s, i-C, Ph + SO2Ph).
3.6. Growing of single-crystals of 1a, 2a, and 4a
3.6.1. [{Li{CH(Me)SO2Ph}(thf)} ] (1a)
1
At
room
temperature
Li[CH(Me)SO2Ph]
(1)
(10.0 mmol, 1.76 g), prepared as described above, was dis-
solved in thf (10 ml). Heating for 5 min to 50 ꢁC resulted in
a clear orange solution. Cooling to room temperature and
addition of n-hexane (5 ml) resulted in crystallization of
[{Li{CH(Me)SO2Ph}(thf)} ] (1a).
1
3.6.2. [{Li{CH(CH2Ph)SO2Ph}(thf)} ] (3a)
1
At room temperature Li[CH(CH2Ph)SO2Ph] (3)
(10.0 mmol, 2.52 g), prepared as described above, was dis-
solved in thf (20 ml). Addition of n-pentane (30 ml)
resulted in crystallization of [{Li{CH(CH2Ph)SO2Ph}-
3.4. Synthesis of Li[CMe(Ph)SO2Ph] (4)
At 0 ꢁC to a stirred suspension of PhCH(Me)SO2Ph
(10.0 mmol, 2.46 g) in toluene (40 ml) was added dropwise
a solution of n-BuLi in n-hexane (10.0 mmol, 1.5 M). Stir-
ring for 2 h at room temperature and addition of n-hexane
(20 ml) resulted in precipitation of 4 as a yellow powder,
which was filtered off, washed with n-pentane (2 · 10 ml)
and dried in vacuo. Yield: 2.25 g (89%). 1H NMR
(400 MHz, thf-d8): d 2.10 (s, 3H, CCH3(Ph)), 6.32–6.36
(m, 1H, p-CH, Ph), 6.85–6.89/7.08–7.10/7.20–7.25/7.72–
7.75 (m/m/m/m, 9H, Ph + SO2Ph). 13C NMR (100 MHz,
(thf)} ] (3a).
1
3.6.3. [{Li{CMe(Ph)SO2Ph}(thf)2}2] (4a)
At 0 ꢁC to a stirred suspension PhCH(Me)SO2Ph
(10.0 mmol, 2.46 g) in thf (40 ml) was added dropwise a
solution of n-BuLi in n-hexane (10.0 mmol, 1.5 M). Stirring
for 30 min at room temperature resulted in a clear brown-
ish-orange solution. Addition of n-pentane (10 ml) and
cooling to ꢀ45 ꢁC resulted in crystallization of [{Li{C-
Me(Ph)SO2Ph}(thf)2}2] (4a) within some days.

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M. Linnert et al. / Journal of Organometallic Chemistry 691 (2006) 2358–2367
Table 6
Crystallographic and data collection parameters for complexes 1a, 3a, and 4a
Compound
1a
3a
4a
Empirical formula
Mr
C12H17LiO3S
248.26
C18H21LiO3S
324.35
C22H29LiO4S
396.45
Crystal system
Space group
Monoclinic
P21/n
5.499(1)
20.358(4)
12.392(5)
Monoclinic
P21/c
13.775(5)
5.5726(8)
23.069(6)
Triclinic
ꢀ
P1
˚
a (A)
9.966(2)
13.795(4)
17.121(5)
93.48(3)
103.14(3)
107.40(3)
2166(1)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
95.16(4)
102.55(4)
3
˚
V (A )
1381.6(8)
4
1.194
0.226
528
1728.6(8)
4
1.246
0.197
688
Z
4
Dcalc (g cmꢀ1
)
1.216
0.173
848
l(Mo Ka) (mmꢀ1
F(000)
)
h Range (ꢁ)
Number of reflections collected
2.59–25.00
14661
2.60–26.08
11269
2.12–25.00
9420
Number of reflections observed [I > 2r(I)]
1562
2104
3292
Number of independent reflections (Rint
Data/restraints/parameters
Goodness-of-fit on F2
)
2444 (0.1184)
2444/0/172
0.957
3249 (0.0632)
3249/0/208
0.955
6507 (0.0656)
6507/0/505
0.901
R1, wR2 [I > 2r(I)]
R1, wR2 (all data)
Largest difference in peak and hole (e A
0.0537, 0.1288
0.0902, 0.1455
0.281 and ꢀ0.322
0.0484, 0.1172
0.0790, 0.1290
0.293 and ꢀ0.298
0.0646, 0.1589
0.1339, 0.2014
0.313 and ꢀ0.435
ꢀ3
˚
)
3.7. X-ray structure determinations
4. Supplementary material
Crystals of 1a, 3a, and 4a suitable for X-ray diffrac-
tion measurements were obtained as described above.
Intensity data were collected on a STOE IPDS diffractome-
ter at 220(2) K (3a, 4a) and 268(2) K (1a), respectively,
using graphite monochromatized Mo Ka radiation (k =
CIF’s have been deposited in the Cambridge Crystallo-
graphic Data Centre, with the numbers CCDC-296930
(1a), CCDC-296931 (3a), and CCDC-296932 (4a).
Acknowledgements
˚
0.71073 A). A summary of the crystallographic data, the
data collection parameters, and the refinement parameters
is given in Table 6. Absorption corrections were applied
Financial support by the Deutsche Forschungsgemeins-
chaft is gratefully acknowledged. We thank Merck
(Darmstadt) for gifts of chemicals.
numerically (Tmin/Tmax
: 0.90/1.00, 1a; 0.96/0.98, 3a;
0.92/0.98, 4a). The structures were solved by direct methods
with SHELXS-97 and refined using full-matrix least–squares
routines against F2 with SHELXL-97 [27]. Non-hydrogen
atoms were refined with anisotropic displacement parame-
ters. Hydrogen atoms were placed in calculated positions
and refined isotropically with fixed displacement parameters
(riding model). In 1a the C atoms of the thf molecule are dis-
ordered over two positions with occupanices of 71(1)% and
29(1)%; the C atoms of the minor occupied positions were
isotropically refined.
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