Synthesis of mono- and geminal dimetalated carbanions of bis(phenylsulfonyl)methane using alkali metal bases and structural comparisons with lithiated bis(phenylsulfonyl)imides

Article abstract of DOI:10.1039/b504730g

The α,α'-stabilized carbanion complexes [(PhSO ₂)₂CHLi-THF] 1, [(PhSO₂)₂CHNa-THF] 2 and [(PhSO₂)₂CHK] 3 were prepared by the direct deprotonation of bis(phenylsulfonyl)methane I in THF with

Full text of DOI:10.1039/b504730g

View Article Online / Journal Homepage / Table of Contents for this issue
F U L L P A P E R
Synthesis of mono- and geminal dimetalated carbanions of
bis(phenylsulfonyl)methane using alkali metal bases and structural
comparisons with lithiated bis(phenylsulfonyl)imides
Dugald J. MacDougall,a Alan R. Kennedy,b Bruce C. Nolla and Kenneth W. Henderson*a
a Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN,
46556, USA. E-mail: khenders@nd.edu; Fax: (574) 631 6652; Tel: (574) 631 8025
b Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK G1 1XL
Received 5th April 2005, Accepted 5th May 2005
First published as an Advance Article on the web 19th May 2005
ꢀ
The a,a -stabilized carbanion complexes [(PhSO2)2CHLi·THF] 1, [(PhSO2)2CHNa·THF] 2 and [(PhSO2)2CHK] 3
were prepared by the direct deprotonation of bis(phenylsulfonyl)methane I in THF with one molar equivalent of
MeLi, BuNa and BnK respectively. The geminal dianionic complexes [(PhSO2)2CLi2·THF] 4, [(PhSO2)2CNa2·
0.55THF] 5 and [(PhSO2)2CK2] 6 were similarly prepared by the reaction of I with two molar equivalents of MeLi,
BuNa and BnK respectively in THF. NMR and MS solution studies of 1–3 are consistent with the formation of
charge-separated species in DMSO media. Solutions studies of 4–6, in conjunction with trapping experiments,
indicate that the dianions deprotonate DMSO and regenerate the monoanions 1–3. Crystallographic analysis of 1
revealed a 1D chain polymer in which the metal centers are chelated by the bis(sulfonyl) ligands and connect to
neighboring units through Li–O(S) interactions. An unexpected feature of 1 is that the polymeric chains are
homochiral, since the chelating ligands of the backbone adopt the same relative configuration. Also, the phenyl
substituents of each chelate in 1 are oriented in a cisoid manner. The sodium derivative 2 adopts a related
solid-state structure, where enantiomeric pairs of chains combine to give a 1D ribbon motif. The lithium
bis(phenylsulfonyl)imides [(PhSO2)2NLi·THF] 9 and [(PhSO2)2NLi·Pyr2] 10 were also prepared and structurally
characterized. In the solid state 9 has a similar connectivity to that found for 1 but with heterochiral chains. In
comparison, the more highly solvated complex 10 forms a 1D polymeric arrangement without chelation of the
ligands and with the phenyl substituents oriented in a transoid fashion.
identification of the organometallic intermediates. Caution
Introduction
should be applied in such instances due to the possible formation
of “quasi dianionic complexes” (QUADACs).11 QUADACs are
co-complexes between a metal base and a carbanion that mimic
the expected reaction profile of a geminal dianion.
Highly reactive carbanions are fundamental synthons in the
preparation of new bonds in organic synthesis.1 Typically,
the carbanionic intermediates are generated in situ by the
deprotonation of an activated carbon center with a metal base,
such as an alkyllithium reagent. Popular activating groups
include sulfonyl,2,3 phosphonate4,5 and nitrile6 moieties, due to
their excellent electron withdrawing properties coupled with the
ease of their subsequent derivatization or complete removal from
a product. Considering the importance of lithiated a-stabilized
carbanions in particular, it is no surprise that the aggregation
behavior of these species has been extensively studied both
theoretically and experimentally.2–8 A commonly encountered
structural pattern is the formation of dimeric aggregates, where
the metals are bridged by the most electronegative groups rather
than binding to the carbanion (Fig. 1).
Our contribution to this area has focused on elucidating
ꢀ
the aggregated structures adopted by monometalated a,a -
stabilized carbanions and investigating the potential of these
species as precursors for geminal dianion synthesis. We ra-
tionalized that the presence of a second electron withdraw-
ing group will result in increased acidity of the neighboring
protons and facilitate the generation of geminal dianions
by direct deprotonation routes. During the course of these
investigations we have synthesized and structurally charac-
ꢀ
terized the a,a -stabilized monocarbanions of several systems
including cyanophosphonates,12 (organosulfonyl)acetonitriles,13
b-diphosphonates,14 and b-diphosphine oxides.15 These mono-
carbanions display unexpected aggregation behaviors com-
pared to their singly a-stabilized analogues, and we have
begun to establish new structural patterns within this area.
In an extension to this work we now report the synthesis
and characterization of the monocarbanions and the geminal
dianions of bis(phenylsulfonyl)methane using lithium, sodium
and potassium as the countercations. These studies include
the structural characterization of a monolithiated and a
monosodiated complex. In addition, two lithiated complexes of
bis(phenylsulfonyl)imine were prepared and characterized for
comparative purposes.
Fig. 1 Common structural motifs associated with monolithiated
carbanions stabilized by: a) sulfones, b) phosphonates and c) nitriles. L =
Lewis base.
Results and discussion
In certain instances geminal dianions may be prepared by a
second deprotonation of the carbanion.9 However, only a hand-
ful of lithiated geminal dianions have been characterized.10 Gem-
inal dianion formation is often assumed on the basis of the sys-
tem’s observed reaction chemistry, rather than through the direct
Syntheses and spectroscopic analyses
Reaction of bis(phenylsulfonyl)methane I with one molar equiv-
alent of MeLi, BuNa or BnK in THF leads to the formation
2 0 8 4
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1
T h i s j o u r n a l i s
T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 5
©

View Article Online
Table 1 Selected 1H and 13C NMR data for the neutral ligand I and compounds 1–3 in d6-DMSO. THF signals are omitted
dH (ppm)
dC (ppm)
Compound
CH2/CH−
o-H
m-H
p-H
CH2/CH−
o-C
m-C
p-C
i-C
I
5.91
3.67
3.67
3.69
7.89
7.72
7.71
7.70
7.61
7.32
7.31
7.31
7.75
7.32
7.31
7.31
71.81
63.75
63.75
63.80
128.32
125.16
125.13
125.09
129.14
127.68
127.65
127.67
134.40
128.93
128.90
128.62
138.84
150.48
150.38
150.24
1
2
3
of the monodeprotonated species [(PhSO2)2CHLi·THF] 1,
[(PhSO2)2CHNa·THF] 2 and [(PhSO2)2CHK] 3 respectively.
Performing similar reactions using two molar equivalents
of the bases results in formation of the doubly metalated
products [(PhSO2)2CLi2·THF] 4, [(PhSO2)2CNa2·0.55THF] 5
and [(PhSO2)2CK2] 6. Upon precipitation, compounds 1–6 are
insoluble in non-polar hydrocarbon or arene solvents, and
only the monoanions 1 and 2 were found to display noticable
solubility in hot pyridine. All of the compounds did completely
dissolve in DMSO and this was therefore chosen as solvent
media for the subsequent NMR spectroscopic studies. Strong
heating was required to prepare homogeneous solutions for the
dianionic species 4–6.
metal and ligand were detected, with the most abundent of these
ions being [{(PhSO2)2CH}2Li]−.
Quenching studies
To further probe the possible reaction between the geminal
dianions 4–6 and DMSO a series of in situ MeI quenching
studies were performed. Either one or two molar equivalents
of the appropriate base (MeLi, BuNa or BnK) were added
to THF solutions of I, followed by stirring for 2 h. After this
time excess MeI was added to the heterogeneous mixtures and
the organic products extracted following aqueous workup. A
second set of experiments was performed where the THF media
was replaced by DMSO prior to the addition of MeI. Three
products were identified by GCMS analyses, starting material
(PhSO2)2CH2 I, monomethylated (PhSO2)2CH(CH3) 7 and
dimethylated (PhSO2)2C(CH3)2 8 (Table 2). Although all of
the reactions resulted in mixtures of products, a clear pattern
could be discerned. Alkylation of the ‘monometalated’ and
‘dimetalated’ substrate in THF solutions resulted in the major
products, monomethylated 7 and dimethylated 8 respectively. In
comparison, all of the quenches performed in DMSO resulted in
monomethylated 7 as the major product. These results support
the view that the geminal dianions react with DMSO and
demonstrate the need for care when assigning the nature of these
highly reactive intermediates.
Table 1 lists the chemical shift data obtained on dissolution
of 1–3 in d6-DMSO. These spectra clearly confirm that the
methylene units were singly deprotonated. As expected, the 1H
NMR studies show an upfield shift of ∼2.2 ppm for the a-
CH following deprotonation, corresponding with an increase in
electron density at the carbanionic center. The 13C NMR spectra
show a similar trend, with the carbanionic CH signals shifted
1
upfield by ∼8.0 ppm. Comparison of the H and 13C NMR
spectra for compounds 1–3 indicates that the identity of the
counter ion (Li, Na or K) has little effect on the chemical shift
positions. The most likely explanation for these observations is
that solvent-separated ion pairs (SSIP) are formed in the strongly
basic solvent DMSO. This situation would lead to essentially
identical free carbanions, (PhSO2)2CH−, in each of the solutions.
Finally, as additional verification of this metalation process
the dilithio complex 4 was dissolved in protic DMSO and the
1H and 13C NMR spectra of the solution was recorded. This
resulted in the reappearance of the expected carbanionic CH
signals for the monoanion 1 in both the 1H and 13 NMR spectra.
1
The H NMR spectra of the geminal dianions 4–6 show no
signal for the carbanion, consistent with twofold deprotonation
of the methylene unit. Also, no signal for the carbanionic carbon
could be detected in the 13C NMR spectra even after extended
acquisition times.16 However, a curious finding was that there
was essentially no difference between the remaining signals of
spectra obtained for the dimetalated species 4–6 and those of
the related monometalated species 1–3. This is unexpected since
the presence of a second negative charge within the ligand
framework should cause significant changes to the electron
distribution within 4–6. We considered that this may be due
to deuterium/metal exchange between the geminal-dianion and
d6-DMSO leading to the regeneration of the monometalated
carbanion (Scheme 1). This scenario would explain the overall
similarity between the spectra of the mono- and dianions and
also for the loss of the 13C NMR signal for the carbanionic center
due to supression by the deuterium.
Crystallographic studies
Surprisingly little has appeared in the literature regarding
the structural characterization of metalated complexes of
bis(phenylsulfonyl)methane. Indeed, a search of the Cam-
bridge Structural Database indicated only a single report of
such a metal complex, the monomeric diaurated compound
[{(Ph3P)Au}2{l-C(SO2Ph)2}].17 Interestingly, this compound
Table 2 Conversion of monoanions 1–3 and dianions 4–6 to
(PhSO2)2CH2 I, (PhSO2)2CH(CH3) 7 and (PhSO2)2C(CH3)2 8 following
MeI quenching
% Ratios obtained
by GC analyses (%)
Base
Mol. equiv.
Solvent
I
7
8
MeLi
BuNa
BnK
MeLi
BuNa
BnK
MeLi
BuNa
BnK
MeLi
BuNa
BnK
1
1
1
2
2
2
1
1
1
2
2
2
THF
THF
THF
THF
THF
THF
DMSO
DMSO
DMSO
DMSO
DMSO
DMSO
15.8
4.0
9.3
0.9
2.9
5.7
10.7
14.8
9.2
8.7
7.9
0.0
73.1
83.6
72.0
2.6
15.8
26.7
78.8
80.1
75.7
69.7
72.6
56.1
11.1
12.4
18.7
96.5
81.3
67.6
10.5
5.1
15.1
21.6
19.5
43.9
Scheme 1 Reaction of the dianions with d6-DMSO (M = Li, Na or K).
Electrospray mass spectroscopic studies of the lithium com-
pounds 2 and 4 proved insightful. Each complex was dissolved
in DMSO (5 mM) and their spectra recorded in both positive
and negative ion modes. Very similar spectra were obtained for
each solution and the results were consistent with the dominant
species being the SSIPs [Li·(DMSO)n]+ (where n = 2 or 3), and
(PhSO2)2CH−. Only trace amounts of species containing both
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1
2 0 8 5

View Article Online
was generated by transmetalation of the presumed geminal
dilithio intermediate. Only two complexes of alkali metal com-
plexes of bis(organosulfonyl)methanides have been structurally
characterized.18 These are the Cs and Rb salts of (F3CSO2)2CH−,
which form complex 3D networks.19 The poor solubilty of
compounds 4–6 prevented the preparation of crystalline samples
suitable for X-ray analysis. However, high quality crystals were
successfully obtained from THF solutions of 1 and 2.
The structure of the sodium complex 2 bears some striking
similarities to that of 1 (Fig. 3). Each metal is chelated by one
sulfonyl ligand, through O(2) and O(3), and is also coordinated
to a third sulfonyl oxygen, O(1*) of a neighboring anion to
generate a 1D polymer with identical connectivity to that of 1.
However, the larger coordination sphere of sodium allows an
additional interaction to a sulfonyl oxygen, Na(1)–O(2#), of a
neighboring chain, resulting in a ribbon rather than a simple
chain motif. Overall, the core of the structure is composed of
alternating four membered Na2O2 rings and eight membered
(SO2Na)2 rings. The eight membered ring is reminiscent of the
(SO2Li)2 motif favored by the related lithiosulfones (Fig. 1a).2,3
However, in light of the similarities displayed by 1 and 2, it
appears likely that metal chelation and chain formation are the
dominant structural themes. Penta-coordination of the sodium
centers is completed by ligation of terminal THF molecules.
Analysis of 1 revealed a 1D polymeric chain structure in
which the lithium centers are tetrahedrally coordinated by three
sulfonyl oxygen atoms and the oxygen atom of a pendant
THF molecule (Fig. 2). Each bis(sulfonyl) ligand chelates a
single metal center, with the polymer propagating through
Li(1)–O(1*) contacts between neighboring ‘monomeric’ units.
Overall, three of the four sulfonyl oxygen atoms of each
ligand bind to lithium centers, leaving one oxygen atom, O(3),
uncoordinated. Hence, the geometry adopted by this lithiated
ꢀ
a,a -sulfonyl stabilized carbanion departs from the generalized
eight membered (SO2Li)2 ring motif found for the simple a-
stabilized counterparts (Fig. 1a).2,3
Fig. 2 Section of the polymeric structure of 1. Hydrogen atoms and
disordered sites of the THF are omitted for clarity.
Fig. 3 Section of the polymeric structure formed by 2. Hydrogen atoms
and coordinated THF molecules are omitted for clarity.
An unexpected feature of 1 is the cisoid orientation of the
phenyl groups within each ligand. This can be gauged by the
improper torsion angle of 18.7◦ for C(8)–S(1)–S(2)–C(2). In
comparison, the free ligand I◦has approximately transoid phenyl
groups, with a value of 119.6 for the same torsion angle.20 Any
p–p contribution to the stabilization of the cisoid orientation
is likely to be weak, with only the C(2)–C(8) distances of the
As in 1 the phenyl groups of each ligand are cisoid, with
the improper torsion angle C(2)–S(1)–S(2)–C(8) being 16.3◦.
Also, the ribbon can be considered as being composed of two
cross-linked enantiomeric chains, which are related through an
inversion center.
Examination of the bond lengths and angles found in 1 and
2 indicates that similar charge distributions are present within
the anions. Key bond lengths and angles for 1 and 2 are listed in
Tables 3 and 4 respectively. The mean S–C(1) distances are 1.674
21
˚
adjacent phenyl rings being <3.5 A. Another point to note
in 1 is that the coordination mode of the anion renders the
sulfur atoms chiral. The ligands of each chain adopt the same
relative configuration and the polymers can be described as being
homochiral (Scheme 2).22 However, the crystals themselves are
racemic since adjacent chains in the lattice adopt opposite chiral
configurations.
˚
and 1.678 A in 1 and 2 respectively. This represents a contraction
of ∼6% in comparison to the neutral ligand I,20 1.786(2) A.
˚
These bond lengths lie between those expected for single S–C
23
=
and double S C bonds. Furthermore, a slight elongation of
=
∼1.5% is seen in the S O bonds following metalation (mean
20
˚
˚
1.454 and 1.451 A in 1 and 2 respectively versus 1.432 A in I).
These patterns correlate well with previously reported alkali
metal complexes of a-sulfonyl carbanions.2,3
◦
˚
Table 3 Selected bond lengths (A) and angles ( ) for 1
Li(1)–O(1*)
Li(1)–O(2)
S(1)–C(1)
S(1)–O(1)
S(1)–O(2)
S(1)–C(8)
1.937(7)
1.970(7)
1.679(4)
1.455(3)
1.455(3)
1.774(4)
Li(1)–O(4)
Li(1)–O(5)
S(2)–C(1)
S(2)–O(3)
S(2)–O(4)
S(2)–C(2)
1.972(7)
1.890(7)
1.669(4)
1.445(3)
1.460(3)
1.775(4)
O(1*)–Li(1)–O(4)
O(1*)–Li(1)–O(2)
O(2)–Li(1)–O(4)
S(1)–O(1)–Li(1#)
S(1)–O(2)–Li(1)
S(2)–O(4)–Li(1)
107.4(3)
118.9(4)
95.9(3)
135.1(3)
126.3(3)
130.8(3)
O(5)–Li(1)–O(1*)
O(5)–Li(1)–O(2)
O(5)–Li(1)–O(4)
S(2)–C(1)–S(1)
S(2)–C(1)–H(1)
S(1)–C(1)–H(1)
112.8(4)
107.8(3)
113.0(4)
121.5(3)
117(3)
Scheme 2 Association of monomeric fragments into stereoregular
homochiral (top) and heterochiral (bottom) polymers. Blue and green
coloring of the oxygen atoms is used to highlight the different coordi-
nation modes adopted. Solvation of the lithium centers by THF is not
shown for simplicity.
114(3)
Symmetry transformations used to generate equivalent atoms.* x − 1,
y, z. # x + 1, y, z.
2 0 8 6
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1

View Article Online
◦
˚
Table 4 Selected bond lengths (A) and angles ( ) for 2
Na(1)–O(1*)
Na(1)–O(2)
Na(1)–O(2#)
Na(1)–O(3)
Na(1)–O(5)
S(1)–C(1)
2.3122(17) S(1)–O(1)
2.3130(16) S(1)–O(2)
2.3513(15) S(2)–C(1)
2.3262(16) S(2)–O(3)
2.2818(18) S(2)–O(4)
1.4529(14)
1.4555(14)
1.680(2)
1.4512(15)
1.4440(15)
1.779(2)
1.677(2)
S(1)–C(2)
S(2)–C(8)
O(1*)–Na(1)–O(2)
102.41(6)
1.784(2)
Fig. 5 Section of the polymeric chain formed by 9. Hydrogen atoms
and coordinated THF molecules are omitted for clarity.
O(1*)–Na(1)–O(2#)
O(1*)–Na(1)–O(3)
O(2)–Na(1)–O(2#)
O(2)–Na(1)–O(3)
O(3)–Na(1)–O(2#)
O(5)–Na(1)–O(1#)
O(5)–Na(1)–O(2)
O(5)–Na(1)–O(2#)
O(5)–Na(1)–O(3)
98.70(6)
99.48(6)
78.33(5)
81.35(5)
155.17(6)
121.83(7)
135.60(7)
90.64(6)
94.00(6)
S(1)–O(1)–Na(1D)
S(1)–O(2)–Na(1)
S(1)–O(2)–Na(1#)
123.52(9)
133.69(8)
122.57(8)
Na(1)–O(2)–Na(1#) 101.67(5)
S(2)–O(3)–Na(1)
S(1)–C(1)–S(2)
S(1)–C(1)–H(1)
S(2)–C(1)–H(1)
137.62(9)
122.72(13)
114.5(14)
115.8(14)
Symmetry transformations used to generate equivalent atoms. * x + 1,
y, z. # −x + 2, −y, −z. D x − 1, y, z.
The geometry of the carbanions in 1 and 2 can be considered
as intermediate between sp2 and sp3 hybridized (Fig. 4). The
planarity of the carbanion can be assessed in terms of (i) the
sum of the angles around C(1) (352.5◦ in 1 and 353.0◦ in 2), (ii)
Fig. 6 Section of the polymeric structure formed by 10. Hydrogen
atoms are omitted for clarity.
˚
the deviation of C(1) from the S(1)–S(2)–H(1) plane (0.21 A
˚
in 1 and 0.20 A in 2), and (iii) the pyramidalization angle
pyridine molecules coordinating each lithium. The polymer is
formed through head-to-tail bridging of two ligands by the
metal centers. Also, the phenyl substituents are now oriented
in a transoid fashion, with the improper torsion angle C(1)–
S(1)–S(2)–C(7) being 138.8◦. Each bis(sulfonyl) ligand within a
chain has the same chiral configuration, and again the crystals
are racemic since neighboring chains are enantiomeric.
v1, which is defined as 180◦ minus the improper torsion angle
S1–C1–S2 · · · H1 (32.1◦ in 1 and 30.7◦ in 2).24 Considering all
these factors, it is apparent that there is similar but significant
pyramidalization about the carbanions.
Key bond lengths and angles for 9 and 10 are listed in Tables 5
and 6 respectively. As expected, the mean S–N distances of
˚
1.588 and 1.588 A in 9 and 10 are compressed in comparison
25
˚
to those in the neutral ligand II (1.650 A), whereas the
S O bonds are slightly elongated (mean 1.450 and 1.446 A
˚
=
˚
in 9 and 10, versus 1.415 A in II). These values compare
favorably with those in related compounds.26 Indeed, there is
growing literature related to bis(organo)sulfonamide anions due
to their use in electrochemical devices.27 The closest structural
analogue to the compounds disclosed in this study is the lithium
triflamide complex [(CF3SO2)2NLi·DME] 11 (DME = 1,2-
dimethoxyethane).28 Complex 11 adopts a similar connectivity
Fig. 4 Asymmetric units of 1 and 2 highlighting the pyramidal nature
of the carbanions. Hydrogen atoms except those of the carbanion are
omitted for clarity.
◦
˚
Table 5 Selected bond lengths (A) and angles ( ) for 9
Comparisons with lithiated bis(phenylsulfonyl)imines
Li(1)–O(9)
Li(1)–O(6)
Li(1)–O(3)
Li(1)–O(1)
O(1)–S(1)
O(2)–S(1)
O(3)–S(2)
O(4)–S(2)
N(1)–S(1)
N(1)–S(2)
S(1)–C(1)
S(2)–C(7)
1.898(3)
1.899(3)
1.922(3)
1.937(3)
1.4556(12) O(5)–S(3)
1.4502(12) O(6)–S(3)
1.4596(12) O(7)–S(4)
1.4354(12) O(8)–S(4)
1.5752(14) N(2)–S(3)
1.6014(14) N(2)–S(4)
1.7675(14) S(3)–C(3)
1.7647(14) S(4)–C(19)
Li(2)–O(2*)
Li(2)–O(10)
Li(2)–O(7)
Li(2)–O(5)
1.899(3)
1.904(3)
1.940(3)
1.942(3)
1.4532(12)
1.4534(12)
1.4591(12)
1.4375(13)
1.5759(15)
1.5985(14)
1.7654(14)
1.7673(14)
To investigate if the aggregation patterns observed in 1 and 2
are general to related a,a -bis(sulfonyl) stabilized anions, the
ꢀ
alkali metal salts of bis(phenylsulfonyl)imine, (PhSO2)2NH,
II were targeted for study. Two complexes were successfully
prepared and characterized by single crystal X-ray crystal-
lography. Reaction of II with BuLi in THF or Pyr (Pyr =
pyridine) followed by crystallization resulted in the formation of
[(PhSO2)2NLi·THF] 9 and [(PhSO2)2NLi·Pyr2] 10 respectively.
Crystallographic analysis of 9 revealed 1D polymeric strands in
which the lithum atoms are tetrahedrally coordinated to three
sulfonyl oxygen atoms and the oxygen atom of a terminally
bonded THF molecule (Fig. 5). Indeed, the connectivity in 9
again matches that found in 1. However, a significant difference
between the structures is that adjacent ligands within the chains
of 9 now adopt opposite chiral configurations, i.e. the polymers
are heterochiral (Scheme 2). Nevertheless, the phenyl groups of
each ligand remain cisoid, with the two independent improper
torsion angles C(1)–S(1)–S(2)–C(7) and C(13)–S(3)–S(4)–C(19)
being 17.1 and 17.2◦ respectively.
O(9)–Li(1)–O(6)
O(9)–Li(1)–O(3)
O(6)–Li(1)–O(3)
O(9)–Li(1)–O(1)
O(6)–Li(1)–O(1)
O(3)–Li(1)–O(1)
S(1)–O(1)–Li(1)
S(1)–O(2)–Li(2#)
S(2)–O(3)–Li(1)
105.24(15) O(2*–Li(2)–O(10)
116.77(17) O(2*–Li(2)–O(7)
114.11(16) O(10)–Li(2)–O(7)
108.29(15) O(2*–Li(2)–O(5)
115.78(17) O(10)–Li(2)–O(5)
96.85(14) O(7)–Li(2)–O(5)
125.83(12) S(3)–O(5)–Li(2)
145.48(13) S(3)–O(6)–Li(1)
130.78(12) S(4)–O(7)–Li(2)
105.05(15)
112.46(16)
120.29(18)
119.56(18)
104.20(16)
95.76(14)
126.46(12)
144.12(12)
131.65(12)
Although pyridine solvate 10 crystallizes as a 1D chain its
structure differs markedly from 1, 2 and 9 (Fig. 6). The ligands
no longer chelate metal centers due to the presence of two
Symmetry transformations used to generate equivalent atoms. * x + 1,
y, z. # x − 1, y, z.
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1
2 0 8 7

View Article Online
◦
˚
Table 6 Selected bond lengths (A) and angles ( ) for 10
system. Elemental analyses were performed by the University
of Strathclyde microanalysis service (compounds 1–6) and
Canadian Microanalytical Service Ltd (compounds 9 and 10).
Li(1)–O(1*)
Li(1)–O(3)
N(1)–S(1)
O(1)–S(1)
O(2)–S(1)
S(1)–C(1)
1.931(2)
1.915(2)
Li(1)–N(2)
Li(1)–N(3)
N(1)–S(2)
O(3)–S(2)
O(4)–S(2)
S(2)–C(7)
2.052(2)
2.047(2)
1.5908(11)
1.4474(9)
1.4396(9)
1.7690(12)
1
It should be noted that the H and 13C chemical shift values
1.5849(11)
1.4562(9)
1.4434(9)
1.7700(13)
obtained on dissolution of compounds 4–6 in d6-DMSO actually
represent the monometalated derivatives due to reaction with the
solvent, as outlined in the text. However, they are included here
for completeness. Also, the compounds tended to lose solvent
on evacuation, with the degree of solvent loss varying depending
on the isolation conditions. Therefore, the formulae used for the
analytical determinations are based on the 1H NMR integration
vaules obtained for the specific samples analyzed.
O(1*)–Li(1)–N(2)
O(1*)–Li(1)–N(3)
O(3)–Li(1)–O(1*)
S(1)–O(1)–Li(1#)
115.90(12)
105.83(11)
115.80(12)
133.82(9)
O(3)–Li(1)–N(2)
O(3)–Li(1)–N(3)
N(3)–Li(1)–N(2)
S(2)–O(3)–Li(1)
102.78(11)
104.01(11)
112.07(11)
166.47(9)
Symmetry transformations used to generate equivalent atoms. * −x +
2, y − 1/2, −z + 1/2. # −x + 2, y + 1/2, z + 1/2.
Preparations and characterizations
[(PhSO2)CHLi·THF] 1. MeLi (1 mmol, 0.78 mL) was
added dropwise to a hot solution of bis(phenylsulfony)methane
(1 mmol, 296 mg) in THF (20 mL). Slow cooling of the
to that of 1 and 9 but with penta-coordination of the metal
centers due to chelation by the didentate DME molecules. Also,
the trifluoromethyl substituents are oriented in an approximately
transoid arrangement in comparision to the cisoid phenyl groups
in 1 and 9. The transoid orientation is presumably preferred in
11 due to steric factors.
◦
resulting solution in a water bath (60 C to ambient) resulted
in the formation of high quality crystals (colorless needles).
The product loses THF on isolation/exposure to vacuum. The
yield and all analyses are based on the formula C16H17S2O4.75Li
as indicated by integration of the 1H NMR spectra. Yield:
195 mg, 55% (Found C, 52.62; H, 4.82. C16H17S2O4.75Li requires
C, 53.92; H, 4.81%); dH (d6-DMSO) 1.76 (3H, m, CH2, THF),
3.60 (3H, m, OCH2, THF), 3.67 (1H, s, CH), 7.32 (6H, m, m-
and, p-H, Ph) and 7.72 (4H, m, o-H, Ph); dC (d6-DMSO) 25.10
(CH2, THF), 63.75 (CH), 67.00 (OCH2, THF), 125.16 (o-C,
Ph), 127.68 (m-C, Ph), 128.93 (p-C, Ph) and 150.48 (i-C, Ph).
MS: 295 [(PhSO2)2CH]−, 598 [(PhSO2)CHLi(PhSO2)CH]−, 241
(Li·3DMSO)+, 163 (Li·2DMSO)+.
[(PhSO2)CHNa·THF] 2. BuNa (1 mmol, 80 mg) was added
to a −78 ◦C cooled solution of bis(phenylsulfonyl)methane
(1 mmol, 296 mg) in THF (30 mL). The resulting solution was
slowly warmed to room temperature resulting in the formation
of a white microcrystalline solid. The solid was removed by
filtration and high quality crystals were obtained by storing the
filtrate for 3 days at ambient temperature (colorless needles). The
product loses THF on isolation/exposure to vacuum. The yield
and all analyses are based on the formula C16H17S2O4.75Na as
indicated by integration of the 1H NMR spectra. Yield: 250 mg,
66% (Found C, 52.07; H, 4.34. C16H17S2O4.75Na requires C, 51.88;
H, 4.08%); dH (d6-DMSO) 1.76 (3H, m, CH2, THF), 3.60 (3H,
m, OCH2, THF), 3.67 (1H, s, CH), 7.31 (6H, m, m- and p-H, Ph)
and 7.71 (4H, m, o-H, Ph); dC (d6-DMSO) 25.08 (CH2, THF),
63.75 (CH), 66.97 (OCH2, THF), 125.13 (o-C, Ph), 127.65 (m-C,
Ph), 128.90 (p-C, Ph) and 150.38 (i-, Ph).
Conclusions
Our studies confirm that both the mono- and geminal dianions
of bis(phenylsulfonyl)methane can be prepared by its direct de-
protonation with the appropriate stoichiometry of MeLi, BuNa
or BnK in THF solution. Our solution studies demonstrated that
the geminal dianions react with the solvent media d6-DMSO to
regenerate the monanions. On reflection this rearrangement is
perhaps not unexpected considering that DMSO has been widely
employed as a protic solvent in determining the equilbrium
acidities of organic molecules.29
The solid-state structural studies of 1 and 2 reveal a close
relationship between the lithium and sodium derivatives of the
monocarbanion. In combination, it appears that the primary
structural motif is chelation of the metal centers by the ligand
followed by association with neighboring units to form 1D
chains, rather than the formation of dimeric (SO2M)2 rings that
are found in simple a-stablized species.
This 1D chain motif is also retained in the related lithium
bis(phenylsulfonyl)imide 9, where again each metal is singly-
solvated by THF. Use of the stronger and sterically less demand-
ing base pyridine results in two solvent molecules coordinating
to each metal center, and formation of a non-chelated 1D chain
polymer.
A THF solution (5 mL) of bis(phenylsulfonyl)methane was
Experimental
◦
added to a −78 C cooled solution of BnK (1 mmol, 130 mg)
in THF (20 mL). The resulting solution quickly turned from
dark red/brown to colorless before a white precipitate rapidly
formed. This was isolated by filtration, washed with hexane
(2 × 10 mL), dried under vacuum and transferred to a glove
box for analysis. Yield: 320 mg, 93% (Found C,46.43; H, 3.15.
C13H9S2O4K requires C, 46.97; H, 2.73%); dH (d6-DMSO) 3.69
(1H, s, CH), 7.31 (6H, m, m- and p-H, Ph) and 7.70 (4H, m, o-H,
Ph); dC (d6-DMSO) 63.80 (CH), 125.09 (o-C, Ph), 127.67 (m-C,
Ph), 128.62 (p-C, Ph) and 150.24 (i-C, Ph).
General procedures
All experimental manipulations were performed under an
inert atmosphere using standard Schlenk techniques or in
an argon-filled glovebox.30 THF was distilled from sodium–
˚
benzophenone ketyl and stored over 4 A molecular sieve
prior to use. Pyridine was distilled from CaH2 and stored
˚
over 4 A molecular sieve prior to use. DMSO was purchased
31
˚
from Fisher and dried by passage over 4 A molecular sieves.
Bis(phenylsulfonyl)methane was purchased from Aldrich and
used as supplied. Bis(phenylsulfonyl)imine was purchased from
Fluka and used as supplied. Methyllithium and n-butyllithium
were purchased from Aldrich as 1.6 M solutions in diethyl ether
and hexanes respectively, and were standardized before use.32
Methyl iodide was purchased from Alfa Aesar and distilled from
CaI2 immediately before use. Butylsodium and benzylpotassium
were prepared following reported literature procedures.33 The
NMR spectra were recorded on Bruker DPX 400 or Varian-
300 spectrometers at 298 K, and were referenced internally
to the residual signals of the deuterated solvent. Mass spectra
were recorded on a Micromass Triple Quadrupole LC-MS-MS
[(PhSO2)CLi2·THF] 4. MeLi (2 mmol, 1.25 mL) was added
to a solution of bis(phenylsulfonyl)methane (1 mmol, 296 mg)
in THF (30 mL). After stirring the resulting mixture for 3 hours,
an off white precipitate was isolated via filtration, washed with
hexane (2 × 10 mL) and dried under vacuum. The resulting light
brown solid was then transferred to a glove box for analysis.
Yield: 370 mg, 97% (Found C, 52.36; H, 5.03; C17H18S2O5Li2
requires C, 53.69; H, 4.77%); dH (d6-DMSO) 1.75 (4H, br, CH2,
THF), 3.60 (4H, br, OCH2, THF), 7.32 (6H, br, m- and p-H, Ph)
and 7.72 (4H, br, o-H, Ph); dC (d6-DMSO) 25.13 (CH2, THF),
67.03 (OCH2, THF), 125.17 (o-C, Ph), 127.71 (m-C, Ph), 128.97
2 0 8 8
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1

View Article Online
(p-C, Ph) and 150.57 (i-C, Ph). MS: 295 [(PhSO2)2CH]−, 598
[(PhSO2)CHLi(PhSO2)CH]−, 241 (Li·3DMSO)+.
[(PhSO2)NHLi·Pyr2] 10. BuLi (5 mmol, 3.2 mL) was added
to a solution of bis(phenylsulfonyl)imine (5 mmol, 1480 mg) in
pyridine (5 mL) to give a white preciptate. Dissolution of the
precipitate was achieved by strong heating and dilution with
additional pyridine (10 mL). Slow cooling of the solution in a
water bath (60 ◦C to ambient) resulted in the formation of high
quality crystals (colorless blocks). The product loses pyridine
on isolation/exposue to vacuum. All analyses and the yield
are based on the formula C18.8H16.8N2.4O4S2Li as indicated by
integration of the 1H NMR spectra. Yield 1910 mg, 94% (Found
56.91; H, 4.30; N, 8.92. C18.8H16.8N2.36O4S2Li requires C, 54.96;
H, 4.12; N 8.05%); dH (d6-DMSO) 7.38 (8.7H, m, m-H, Pyr and
m- and p-H, Ph), 7.68 (4H, m, o-H,Ph), 7.77 (1.34H, m, p-H,
Pyr) and 8.58 (2.7H, m, o-H, Pyr); dC (d6-DMSO) 124.63 (m-
C, Pyr), 126.83 (o-C, Ph), 128.54 (m-C, Ph), 130.69 (p-C, Ph),
136.86 (p-C, Pyr), 147.22 (i-C, Ph) and 150.32 (o-C, Pyr).
[(PhSO2)CNa2·0.55THF] 5. BuNa (2 mmol, 160 mg)
was added to a −78 ◦C cooled solution of bis(phenyl-
sulfonyl)methane (1 mmol, 296 mg) in THF (30 mL). The
resulting mixture was stirred for 1 hour at −78 ◦C then allowed to
warm to room temperature. This gave a brown precipitate which
was isolated by filtration, washed with hexane (2 × 10 mL), dried
under vacuum and then transferred to a glove box for analysis.
The amount of THF in the final product was determined from
integration of the 1H NMR spectra. The yield and all analyses
are based on the molecular formula C15.2H14.4S2O4.55Na2. Yield:
340 mg, 89% (Found C, 48.11; H, 4.17. C15.2H14.4S2O4.55Na2
requires C, 48.05; H, 3.82%); dH (d6-DMSO) 1.76 (2.2H, m,
CH2, THF), 3.60 (2.2H, m, OCH2, THF), 7.31 (6H, m, m- and
p-H, Ph) and 7.70 (4H, m, o-H, Ph); dC (d6-DMSO) 25.13 (CH2,
THF), 67.02 (OCH2, THF), 125.15 (o-C, Ph), 127.71 (m-C, Ph),
128.97 (p-C, Ph) and 150.34 (i-C, Ph).
Quenching studies
One or two molar equivalents of the appropriate base (MeLi,
BuNa or BnK) were added to THF solutions (20 mL) of I
(1 mmol, 296 mg), followed by stirring for 2 h. After this time
excess MeI (2 mL) was added to the heterogeneous mixtures and
the organic products extracted into EtOAc (3 × 30 mL) following
aqueous workup. The products were identified by GC-MS and
NMR spectroscopy. Quenches in DMSO were performed in a
similar manner with the exception that the THF was removed
under vacuum and replaced with DMSO (20 mL) immediately
prior to the addition of MeI.
[(PhSO2)CK2] 6. A THF solution (5 mL) of bis(phenyl-
sulfonyl)methane (1 mmol, 296 mg) was added to a −78 ◦C
cooled solution of BnK (2 mmol, 260 mg) in THF (20 mL).
The mixture immediately changed color from dark red/brown
to white accompanied by the formation of a precipitate. The
reaction was allowed to slowly warm to room temperature and
stirred overnight. Then the light brown product was isolated by
filtration, washed with hexane (2 × 10 mL), dried under vacuum
and transferred to a glove box for analysis. Yield: 350 mg, 94%
(Found C, 41.68; H, 2.83. C13H10S2O4K2 requires C, 41.91; H,
2.71%); dH (d6-DMSO) 7.31 (6H, m, m- and p-H, Ph) and 7.71
(4H, m, o-H, Ph); dC (d6-DMSO) 125.12 (o-C, Ph), 127.65 (m-C,
Ph), 128.90 (p-C, Ph) and 150.39 (i-C, Ph).
X-Ray crystallography
Specific crystallographic data and refinement parameters for 1,
2, 9 and 10 are listed in Table 7. In all cases the crystalline samples
were placed under a blanket of inert oil, mounted on a glass pin
and transferred to the cold N2 gas stream of the diffractometer.
Single-crystal diffraction data for 1 and 2 were recorded on a
Nonius Kappa CCD using graphite monochromated Mo-Ka
[(PhSO2)NLi·THF] 9. BuLi (2 mmol, 1.25 mL) was added to
a solution of bis(phenylsulfonyl)imine (2 mmol, 594 mg) in THF
(12 mL). A white precipitate quickly formed which dissolved
completely on strong heating. Slow cooling of the solution in
a water bath (60 ◦C to ambient) resulted in the formation
of high quality crystals (colorless needles). The product loses
all coordinated solvent on isolation/exposure to vacuum. All
analyses and the yield are based on the formula (PhSO2)2NLi as
indicated by integration of the 1H NMR spectra. Yield: 380 mg,
63% (Found C, 47.40; H, 3.26; N, 4.61. C12H10NO4S2Li requires
C, 47.52; H, 3.32; N, 4.62%); dH (d6-DMSO) 7.39 (6H, m, m-
and p-H, Ph) and 7.68 (4H, m, o-H,Ph); dC (d6-DMSO) 126.79
(o-C, Ph), 128.56 (m-C, Ph), 130.72 (p-C, Ph) and 147.16 (i-C,
Ph).
˚
(k = 0.71073 A) radiation at 123 K and 150 K respectively.
Crystal data for 9 and 10 were collected and integrated using
a Bruker SMART Apex system, with graphite monochromated
˚
Mo-Ka (k = 0.71073 A) radiation at 100 K. The structures were
solved by direct methods using SHELXS-97 and refined using
SHELXL-97.34 All non-H atoms were found by successive full-
matrix least-squares refinement on F2 and were refined with
anisotropic thermal parameters. Disorder was modelled for one
THF molecule of 1, 2 and 9. C(17) of compound 1 was modeled
over two sites with a freely refined occupancy of 0.768(16) :
Table 7 Crystallographic data for compounds 1, 2, 9 and 10
Compound
1
2
9
10
Empirical formula
M
T/K
C17H19LiO5S2
374.38
123(2)
C17H19NaO5S2
390.43
150(2)
C32H36Li2N2O10S4
750.75
100(2)
C20H22LiN3O4S2
461.47
100(2)
Crystal system
Space group
Monoclinic
P21/n
Monoclinic
P21/n
Monoclinic
P21/n
Monoclinic
P21/c
˚
a/A
5.7976(4)
34.489(3)
9.0798(8)
103.882(2)
1762.5(3)
4
5.9292(1)
27.1577(5)
11.2618(2)
96.258(1)
1802.61(6)
4
10.8793(7)
9.3620(6)
34.239(2)
94.697(1)
3475.6(4)
4
10.7604(6)
12.8589(7)
16.3444(9)
105.549(1)
2178.8(2)
4
˚
b/A
˚
c/A
b/◦
V/A
3
˚
Z
D
calc/Mg m−1
1.411
0.326
1.439
0.344
1.435
0.332
1.407
0.279
l/mm−1
F(000)
Refln. collected
784
9751
816
3669
1568
36012
960
23105
Independent refln. [Rint
]
2947 [0.0740]
1.011
0.0559
3669
1.020
0.0373
0.0841
8630 [0.0252]
1.082
0.0455
5418 [0.0256]
1.051
0.0352
Goodness-of-fit on F2
R1
wR2
0.1149
0.1175
0.0954
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1
2 0 8 9

View Article Online
0.232(16), C(14) of compound 2 was modelled over two sites
with a freely refined occupancy of 0.80(4) : 0.20(4) and C(32) of
compound 10 was modeled over two sites with a fixed occupancy
of 0.63 : 0.37. The carbanionic hydrogen atoms H(1) of 1 and
2 and the aromatic hydrogen atoms of 9 were located in the
difference map and refined isotropically. All other hydrogen
atoms were placed in calculated positions and in riding modes,
with fixed thermal parameters (Uij = 1.2 Uij(eq) for the atom to
which they are bonded).
Harms, M. Marsch, R. Wollert and K. Dehnicke, Chem. Ber., 1992,
125, 87; (e) G. Boche, K. Harms and M. Marsch, J. Am. Chem. Soc.,
1988, 110, 6925; (f) G. Boche, M. Marsch and K. Harms, Angew.
Chem., Int. Ed. Engl., 1986, 25, 373; (g) J. Kaneti, P. v. R. Schleyer,
T. Clark, A. J. Kos, G. W. Spitznagel, J. G. Andrade and J. B. Moffat,
J. Am. Chem. Soc., 1986, 108, 1481.
7 For reviews on structural lithium chemistry see: (a) R. E. Mulvey,
Chem. Soc. Rev., 1998, 27, 339; (b) K. Gregory, P. v. R. Schleyer
and R. Snaith, Adv. Inorg. Chem., 1991, 37, 47; (c) E. Weiss, Angew.
Chem., Int. Ed. Engl., 1993, 32, 1501; (d) M. A. Beswick and D. S.
Wright, in Comprehensive Organometallic Chemistry, eds. E. W. Abel,
F. G. A. Stone and G. Wilkinson, Elsevier, Oxford, 1995, vol. 1, p. 1.
8 For a review on theoretical studies of lithium compounds see:
Lithium Chemistry, A Theoretical and Experimental Overview, eds.
A. M. Sapse and P. v. R. Schleyer, John Wiley and Sons, New York,
1995.
CCDC reference numbers 267871–267874.
See http://www.rsc.org/suppdata/dt/b5/b504730g/ for cry-
stallographic data in CIF or other electronic format.
Acknowledgements
9 (a) I. Marek and J.-F. Normant, Chem. Rev., 1996, 96, 3241; (b) I.
Marek, Chem. Rev., 2000, 100, 2887; (c) J. F. K. Mu¨ller, Eur. J. Inorg.
Chem., 2000, 789.
We gratefully acknowledge the University of Notre Dame
for financial assistance (KWH and DJM). We also thank Dr
William Boggess (Univeristy of Notre Dame) for expertize with
the mass spectroscopic studies and the referees of this paper for
their helpful suggestions.
10 (a) J. Vollhardt, H.-J. Gais and K. L. Lukas, Angew. Chem., Int. Ed.
Engl., 1985, 24, 610; (b) J. Vollhardt, H.-J. Gais and K. L. Lukas,
Angew. Chem., Int. Ed. Engl., 1985, 24, 696; (c) J. F. K. Mu¨ller,
M. Neuburger and M. Zehnder, Helv. Chim. Acta, 1997, 80, 2182;
(d) J. F. K. Mu¨ller, M. Neuburger and B. Spingler, Angew. Chem. Int.
Ed., 1999, 38, 3549; (e) J. F. K. Mu¨ller, M. Neuburger and B. Spingler,
Angew. Chem. Int. Ed., 1999, 38, 92; (f) W. Zarges, M. Marsch and K.
Harms, Chem. Ber., 1989, 122, 1307; (g) A. Kasani, R. P. Kamelesh
Babu, R. McDonald and R. G. Cavell, Angew. Chem. Int. Ed., 1999,
38, 1483; (h) C. M. Ong and D. W. Stephan, J. Am. Chem. Soc., 1999,
121, 2939.
11 (a) P. J. Crowley, M. R. Leach, O. Meth-Cohn and B. J. Wakefield,
Tetrahedron Lett., 1986, 27, 2909; (b) W. Zarges, M. Marsch, K.
Harms and G. Boche, Angew. Chem., Int. Ed. Engl., 1989, 28, 1392;
(c) J. Corset, M. Castella`-Ventura, F. Froment, T. Strzalko and L.
Wartski, J. Org. Chem., 2003, 68, 3902; (d) J. Corset, M. Castella`-
Ventura, F. Froment, T. Strzalko and L. Wartski, Spectrochim. Acta,
Part A, 2002, 58, 1971.
References and notes
1 (a) J. Clayden and S. Warren, Angew. Chem., Int. Ed. Engl., 1996,
35, 241; (b) Comprehensive Organic Synthesis, eds. B. M. Trost and
I. Flemming, Permagon, Oxford, 1991, vols. 1 and 2; (c) Compre-
hensive Carbanion Chemistry, eds. E. Buncel and T. Durst, Elsevier,
Amsterdam, 1984.
2 (a) H.-J. Gais, M. van Gumpel, G. Raabe, J. Mu¨ller, S. Braun, H. J.
Lindner, S. Rohs and J. Runsink, Eur. J. Org. Chem., 1999, 1627;
(b) H.-J. Gais, J. Mu¨ller, J. Vollhardt and H. J. Lindner, J. Am.
Chem. Soc., 1991, 113, 4002; (c) H.-J. Gais, G. Hellman and H. J.
Lindner, Angew. Chem., Int. Ed. Engl., 1990, 29, 100; (d) H.-J. Gais, G.
Hellman, H. Gu¨nther, F. Lopez, H. J. Lindner and S. Braun, Angew.
Chem., Int. Ed. Engl., 1989, 28, 1025; (e) H.-J. Gais, J. Vollhardt, G.
Hellman, H. Paulus and H. J. Lindner, Tetrahedron Lett., 1988, 29,
1259; (f) H.-J gais and J. Vollhardt, Tetrahedron Lett., 1988, 29, 1529;
(g) H.-J Gais, J. Vollhardt and H. J. Lindner, Angew. Chem., Int. Ed.
Engl., 1986, 25, 939; (h) H.-J. Gais, H. J. Lindner and J. Vollhardt,
Angew. Chem., Int. Ed. Engl., 1985, 24, 859.
3 (a) G. Boche, Angew. Chem., Int. Ed. Engl., 1989, 28, 277; (b) F.
Bosold, P. Zulauf, M. Marsch, K. Harms, J. Lohrenz and G. Boche,
Angew. Chem., Int. Ed. Engl., 1991, 30, 1455; (c) W. Hollstein, K.
Harms, M. Marsch and G. Boche, Angew. Chem., Int. Ed. Engl., 1988,
27, 846; (d) W. Hollstein, K. Harms, M. Marsch and G. Boche, Angew.
Chem., Int. Ed. Engl., 1987, 26, 1287; (e) G. Boche, M. Marsch, K.
Harms and G. M. Sheldrick, Angew. Chem., Int. Ed. Engl., 1985, 24,
573.
4 (a) W. Clegg, R. P. Davies, L. Dunbar, N. Feed, S. T. Liddle, R. E.
Mulvey, R. Snaith and A. E. H. Wheatley, Chem. Commun., 1999,
1401; (b) D. R. Armstrong, D. Barr, M. G. Davidson, G. Hutton, P.
O’brien, R. Snaith and S. Warren, J. Organomet. Chem., 1997, 529,
97; (c) J. E. Davies, R. P. Davies, L. Dunbar, P. R. Raithby, M. G.
Russel, R. Snaith, S. Warren and A. E. H. Wheatley, Angew. Chem.,
Int. Ed. Engl., 1997, 36, 2334; (d) D. R. Armstrong, R. P. Davies, L.
Dunbar, P. R. Raithby, R. Snaith and A. E. H. Wheatley, Phosphorus,
Sulfur Silicon Relat. Elem., 1997, 125, 51; (e) D. R. Armstrong, M. G.
Davidson, R. P. Davies, H. J. Mitchell, R. M. Oakley, P. R. Raithby,
R. Snaith and S. Warren, Angew. Chem., Int. Ed. Engl., 1996, 35,
1942; (f) I. CraggHine, M. G. Davidson, A. J. Edwards, E. Lamb,
P. R. Raithby and R. Snaith, Chem. Commun., 1996, 153.
5 (a) S. E. Denmark, K. A. Swiss, P. C. Miller and S. R. Wilson,
Heteroat. Chem., 1998, 9, 209; (b) S. E. Denmark, K. A. Swiss and
S. R. Wilson, Angew. Chem., Int. Ed. Engl., 1996, 35, 2515; (c) C. J.
Cramer, S. E. Denmark, P. C. Miller, R. L. Dorow, K. A. Swiss and
S. R. Wilson, J. Am. Chem. Soc., 1994, 116, 2437; (d) S. E. Denmark,
P. C. Miller and S. R. Wilson, J. Am. Chem. Soc., 1993, 115, 3826;
(e) S. E. Denmark, P. C. Miller and S. R. Wilson, J. Am. Chem. Soc.,
1991, 113, 1468; (f) S. E. Denmark and S. L. Dorow, J. Am. Chem.
Soc., 1990, 112, 864; (g) M. Kranz, S. E. Denmark, K. A. Swiss and
S. R. Wilson, J. Org. Chem., 1996, 61, 8551; (h) M. Kranz and S. E.
Denmark, J. Org. Chem., 1995, 60, 5867.
6 (a) D. Enders, J. Kirchhoff, P. Gerdes, D. Mannes, G. Raabe, J.
Runsink, G. Boche, M. Marsch, H. Ahlbrecht and H. Sommer,
Eur. J. Org. Chem., 1998, 3, 63; (b) P. R. Carlier, B. L. Lucht and D. B.
Collum, J. Am. Chem. Soc., 1994, 116, 11602; (c) C. Lambert, P. v.
R. Schleyer, U. Pieper and D. Stalke, Angew. Chem., Int. Ed. Engl.,
1992, 31, 77; (d) W. Hiller, S. Frey, J. Stra¨hle, G. Boche, W. Zarges, K.
12 K. W. Henderson, A. R. Kennedy, A. E. McKeown and D. Strachan,
J. Chem. Soc., Dalton Trans., 2000, 23, 4348.
13 (a) K. W. Henderson, A. R. Kennedy, L. Macdonald and D. J.
MacDougall, Inorg. Chem., 2003, 42, 2839; (b) K. W. Henderson,
A. R. Kennedy and D. J. MacDougall, Inorg. Chem., 2003, 42, 2736;
(c) K. W. Henderson, A. R. Kennedy, D. J. MacDougall and D.
Shanks, Organometallics, 2002, 21, 606; (d) K. W. Henderson and
D. J. MacDougall, Phosphorus, Sulfur Silicon Relat. Elem., 2004,
179, 795.
14 R. Nassar, A. M. Beatty and K. W. Henderson, Eur. J. Inorg. Chem.,
2003, 18, 3325.
15 R. Nassar, B. C. Noll and K. W. Henderson, Polyhedron, 2004, 23,
2499.
16 Similar behaviour was found for the dilithio derivatives of (organosul-
fonyl)acetonitriles, ref. 13c.
17 B. Djordjevic, K. A. Porter, S. Nogai, N. Schier and H. Schmidbaur,
Organometallics, 2003, 22, 5336.
18 K. T. Da˚vøy, T. Gramstad and S. Husebye, Acta Chem. Scand., Ser.
A, 1979, 33, 3.
19 Some transition metal complexes have also been reported: (a) A. R.
Siedle, R. A. Newmark, W. B. Gleason and W. M. Lamana,
Organometallics, 1990, 9, 1290; (b) A. R. Siedle, R. A. Newmark
and L. H. Pignolet, Inorg. Chem., 1986, 25, 3412; (c) A. R. Siedle,
R. A. Newmark and L. H. Pignolet, Organometallics, 1986, 5, 38.
20 C. Glidewell, P. Lightfoot and I. L. J. Patterson, Acta Crystallogr.,
Sect. C, 1995, 51, 1648.
21 (a) C. Janiak, J. Chem. Soc., Dalton Trans., 2000, 3885; (b) C. G.
Classens and J. F. Stoddart, J. Phys. Org. Chem., 1997, 10, 254.
22 This was also the case for [(PhSO2)2CHCNLi·TMEDA]∞, see ref.
13c.
23 F. H. Allen, O. Kennard, D. G. Watson, L. Brammer, A. G. Orpen
and R. Taylor, J. Chem. Soc., Perkin Trans. 2, 1987, S1.
24 For a completely planar carbanion v1 would be 0◦ and for a
tetrahedral atom the v1 value would be 60◦.
25 F. A. Cotton and P. F. Stokely, J. Am. Chem. Soc., 1970, 92, 294.
26 (a) M. G. Davidson, P. R. Raithby, A. L. Johnson and P. D. Bolton,
Eur. J. Inorg. Chem., 2003, 3445; (b) L. Xue, C. W. Padgett, D. D.
DesMarteau and W. T. Pennington, Solid State Sci., 2002, 4, 1535;
(c) A. Blaschette, K.-H. Nagel and P. G. Jones, Z. Naturforsch., Teil
B, 1994, 49, 36.
27 (a) J. L. Nowinski, P. Lightfoot and P. G. Bruce, J. Mater. Chem.,
1994, 4, 1579; (b) D. Scomburg, A. Blaschette and S. Kassomenakis,
Z. Anorg. Allg. Chem., 1991, 604, 47; (c) P. G. Jones, O. Moers and A.
Blaschette, Acta Crystallogr., Sect. C, 1997, 53, 1809; (d) O. Moers,
2 0 9 0
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1

View Article Online
A. Blaschette and P. G. Jones, Z. Anorg. Allg. Chem., 2001, 627, 1611;
(e) O. Moers, A. Blaschette and P. G. Jones, Z. Anorg. Allg. Chem.,
2002, 628, 1377; (f) O. Moers, A. Blaschette and P. G. Jones, Z. Anorg.
Allg. Chem., 2002, 628, 2086.
30 D. F. Schriver and M. A. Drezdon, The Manipulation of Air-Sensitive
Compounds, Wiley, New York, 1986.
31 D. R. Burfield and R. H. Smithers, J. Org. Chem., 1978, 43, 3966.
32 B. E. Love and E. G. Jones, J. Org. Chem., 1999, 64, 3755.
33 L. Lochmann, Eur. J. Inorg. Chem., 2000, 1115.
34 G. M. Sheldrick, SHELXS-97 and SHELXL-97 software for crys-
tal structure determination, University of Go¨ttingen, Germany,
1997.
28 D. Brouillette, D. E. Irish, N. J. Taylor, G. Rerron, M. Odziemkowski
and J. E. Desnoyers, Phys. Chem. Chem. Phys., 2002, 4, 6063.
29 (a) A. Streitwieser, Acc. Chem. Res., 1984, 17, 353; (b) F. G. Bordwell,
Acc. Chem. Res., 1988, 21, 456.
D a l t o n T r a n s . , 2 0 0 5 , 2 0 8 4 – 2 0 9 1
2 0 9 1