Reactions of mono- and bis-N-bromosulfimides with thio-ether crowns, phosphines and selenides

Article abstract of DOI:10.1039/b316850f

The brominated sulfimide Ph₂SNBr reacts with diphosphines 1,2-(PPh₂)₂C₂H₄ and 1,4-(Ph ₂P)₂(C₆H₄) to give the bis-N-phosphoniosulfimidium cations [1,2-(Ph₂PNSPh₂) ₂C₂H₄]²⁺ and [1,4-(Ph ₂PNSPh₂)₂(C₆H₄)] ²⁺, respectively. Treatment of the bis-sulfimide 1,4-[PhSNH] ₂C₆H₄ with N-bromosuccinimide results in 1,4-[PhSNBr]₂C₆H₄, which in turn reacts with triphenylphosphine to generate [1,4-(PhS{NSPPh₃})₂C ₆H₄]Br₂. Both Ph₂SNBr and 1,4-[PhSNBr]₂C₆H₄ react with the thio-ether crown [9-ane]S₃, giving [9[ane]S₃NSPh₂]Br and [1,4-{[9-ane]S₂S(NSPh)₂C₆H₄]Br ₂, respectively. The first examples of seleniosulfimidium salts have been isolated from the reactions of Ph₂SNBr and 1,4(PhS{NBr}) ₂C₆H₄ with Ph₂Se and the structures of the [Ph₂SNSePh₂]⁺ and [1,4-(PhSNSePh ₂)₂C₆H₄]²⁺ cations confirmed by X-ray crystallography. Reaction of 1,2-PhS(NH)C₆H ₄SPh with one equivalent of N-bromosuccinimide followed by addition of Na[BPh₄] results in [1,2-(PhS)₂(μ-N)C ₆H₄][BPh₄] in which a CCSNS ring is observed; two forms of this material may be isolated upon crystallisation-X-ray crystallography reveals them to differ by the relative orientations of the phenyl rings.

Full text of DOI:10.1039/b316850f

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P A P E R
Reactions of mono- and bis-N-bromosulfimides with thio-ether
crowns, phosphines and selenides
Stephen M. Aucott, Mark R. Bailey, Mark R. J. Elsegood, Liam M. Gilby, Kathryn E. Holmes,
´
Paul F. Kelly,* Michael J. Papageorgiou and Sarah Pedron-Haba
Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK.
E-mail: P.F.Kelly@lboro.ac.uk; Fax: +44 (0)1509 223925; Tel: +44 (0)1509 222578
Received (in Montpellier, France) 22nd December 2003, Accepted 29th March 2004
First published as an Advance Article on the web 12th July 2004
The brominated sulfimide Ph2SNBr reacts with diphosphines 1,2-(PPh2)2C2H4 and 1,4-(Ph2P)2(C6H4) to give
the bis-N-phosphoniosulfimidium cations [1,2-(Ph2PNSPh2)2C2H4]2þ and [1,4-(Ph2PNSPh2)2(C6H4)]2þ
,
respectively. Treatment of the bis-sulfimide 1,4-[PhSNH]2C6H4 with N-bromosuccinimide results in 1,4-
[PhSNBr]2C6H4 , which in turn reacts with triphenylphosphine to generate [1,4-(PhS{NSPPh3})2C6H4]Br2 .
Both Ph2SNBr and 1,4-[PhSNBr]2C6H4 react with the thio-ether crown [9-ane]S3 , giving [9[ane]S3NSPh2]Br
and [1,4-{[9-ane]S2S(NSPh)2C6H4]Br2 , respectively. The first examples of seleniosulfimidium salts have been
isolated from the reactions of Ph2SNBr and 1,4(PhS{NBr})2C6H4 with Ph2Se and the structures of the
[Ph2SNSePh2]þ and [1,4-(PhSNSePh2)2C6H4]2þ cations confirmed by X-ray crystallography. Reaction of
1,2-PhS(NH)C6H4SPh with one equivalent of N-bromosuccinimide followed by addition of Na[BPh4] results
in [1,2-(PhS)2(m-N)C6H4][BPh4] in which a CCSNS ring is observed; two forms of this material may be
isolated upon crystallisation—X-ray crystallography reveals them to differ by the relative orientations of the
phenyl rings.
revealed an S–N–S angle of 109.6(5)ꢂ, suggesting a tetrahedral
conformation around the nitrogen atom, with S–N distances
Introduction
6
of 1.60(1) (N–SPh2) and 1.67(1) A. Similarly, the symmetric
˚
In the course of recent work we have been able to demonstrate
that the sulfimide Ph2SNH can act as an excellent ligand
towards a range of metal centres.1 Particular interest in the
results stems not only from the ability of the ligand to stabilise
unusual combinations of coordination geometries but also
from the extensive hydrogen-bonding effects seen in the result-
ing complexes. An obvious strategy for building upon such
results comes in the form of the preparation of structural var-
iations upon the original ligand and we have gone some way
towards this by looking at the chemistry of bis-sulfimides
and mixed sulfide/sulfimides.2 The first examples of both such
species were reported in this journal3 and subsequently shown
to act as effective ligands.2 Similarly, we have been able to iso-
late the first examples of complexes of the substituted sulfimide
Ph2SN(CH2)2CN.4 In order to pave the way for investigations
into more substantial variations upon the original ligand, we
have now begun to investigate reactions of N-halosulfimides
with a variety of species. Only a few reports currently exist
on the synthesis, properties and reactions of these com-
pounds.5
[Me2SNSMe2]þ cation has been structurally characterised
and exhibits an S–N–S angle 110.8ꢂ and S–N bond lengths
7
almost symmetrical at 1.63 and 1.64 A. The only other struc-
˚
turally characterised compound of this type is the N-phospho-
niosulfimide [Ph3PNSPh2][SbCl6],8 formed by the reaction of
N-chlorodiphenylsulfimide and triphenylphosphine, which
˚
has S–N and P–N distances of 1.60(1) A and an S–N–P angle
of 123.6(8)ꢂ.
In order to increase the amount of structural data available
for such compounds and to increase the diversity of systems of
this type, we have now undertaken a variety of novel reactions
within this area. Specifically we have aimed to:
(i) Determine the ability of bis-phosphines to undertake such
reactions.
(ii) Determine the ability of our recently reported example of
a bis-sulfimide, 1,4-[PhSNH]2C6H4 , to act as source of the
corresponding brominated sulfimide and then to undergo
reactions analogous to those noted above.
(iii) Undertake the first investigation of the reactivity of a
thio-crown system towards halosulfimides.
(iv) Investigate the possibility of generating S–N–Se systems
via reaction with a selenide.
(v) Determine the ability of the mixed sulfide/sulfimide sys-
tem 1,2-(PhS{NH})(PhS)C6H4 to undergo intramolecular ring
closure reactions via halosulfimide formation.
N-Halosulfimides, usually prepared by the reaction of an N-
unsubstituted sulfimide and N-bromo- or N-chlorosuccimide
in an inert solvent, are known to react with a variety of sul-
fides, phosphines and tertiary amines to form N-substituted
sulfimidium salts according to eqn. (1):
R2SNX þ ER0n ! ½R2SNER0nꢀþ Xꢁ;
ðE ¼ S; P or N and X ¼ halideÞ ð1Þ
Results and discussion
There is, however, little structural information available on the
products of such reactions. One example of a fully elucidated
system comes in the form of the [Ph2SNSPhMe]þ cation, gen-
erated in the reaction of N-bromodiphenylsulfimide with
methylphenylsulfide. For the X-ray study the resulting bro-
mide salt was converted to the perchlorate and crystallography
Preparation of new N-phosphoniosulfimidium salts
A specific aim of this area of the work was to generate systems
in which more than one cationic PNS unit is present. There are
two approaches that may be taken to the formation of such
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6
959

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systems, namely reaction of Ph2SNBr with bis-phosphines
or, alternatively, the reaction of monophosphines with bis-
bromosulfimides. Here we present examples of both classes
of reaction.
Reaction of 2 equiv of Ph2SNBr with 1,2-(PPh2)2C2H4
(Scheme 1) results in the formation of colourless [1,2-
(Ph2PNSPh2)2C2H4]Br2 (1), which may be crystallised by slow
diffusion of Et2O into a CH2Cl2 solution. X-Ray crystallogra-
phy confirms (Fig. 1) that the cation contains two PNSPh2
units, within which S–N and P–N distances of 1.6224(14)
˚
and 1.6101(14) A, respectively, are observed.
One of the most striking features of the structure of 1 is the
fact that the PNSPh2 units take up positions on opposite sides
of the central axis defined by the ethyl backbone. This presum-
ably reduces steric interactions, which would be significant if
both units were aligned on the same side of the backbone; this
effect does, however, also manifest itself in the structure of the
[1,4-(Ph2PNSPh2)2(C6H4)]2þ cation (Fig. 2), in which the
PNSPh2 units are separated by the intervening phenyl group.
This cation is made in the same manner as 1, by reaction
of 1,4-(Ph2P)2(C6H4) with 2 equiv of Ph2SNBr; in this case
subsequent reaction with Na[BPh4] allows isolation of [1,4-
(Ph2PNSPh2)2(C6H4)][BPh4]2 , 2, which is more readily crystal-
lised than the bromide salt (an effect which will be noted for
many of the systems within this study). In the case of 2 the
S–N bonds are seen to be parallel to each other and at 26ꢂ
to the central phenyl; the P–N bonds point in the opposite
direction relative to the phenyl bridge, at an angle of 39ꢂ. A
comparison of bond distances to those in 1 reveals the S–N dis-
Fig. 1 The crystal structure of the cation in 1. Selected bond lengths
and angles (see text also): N(1)–S(1) 1.6224(14), N(1)–P(1) 1.6101(14)
ꢂ
˚
A; S(1)–N(1)–P(1) 120.68(8) .
reaction of Ph2SNBr with dppe the principal product appears
to be the oxide [1,2-(Ph2PNSPh2)(Ph2PO)C2H4]þ unless the
reaction is performed under rigorously anaerobic conditions.
In previous work we reported the isolation of the first exam-
ple of a bis-sulfimide, namely 1,4-[PhSNH]2C6H4 . Reaction of
this compound with N-bromosuccinimide proceeds in an
entirely analogous manner to that of monosulfimides and
1,4-[PhSNBr]2C6H4 may be isolated as a yellow solid. The
reactivity of this mirrors that of Ph2SNBr in that treatment
with PPh3 generates [1,4-(PhS{NSPPh3})2C6H4]Br2 (3). The
X-ray crystal structure of 3 (Fig. 3) confirms the presence of
the two cationic SNP units; unlike in the structure of 2 the
N–S and P–N bonds are much closer to being in the same
plane as the central phenyl unit.
˚
tance to be significantly shorter in 2 at 1.605(6) A; both this
˚
and the P–N distance [1.603(6) A)] are consistent with substan-
tial double bond character of both bonds and delocalisation of
the positive charge across the SNP unit.
Interestingly, if such reactions are performed in an equimo-
lar ratio, the addition of the Ph2SN unit to one phosphine
appears to activate the other to oxidation. Thus, in the 1:1
The results thus show that brominated monosulfimides react
with diphosphines and that brominated bis-sulfimides react
with monophosphines. This raises the possibility of combining
the two reaction strategies and generating cyclic structures by
reaction of a brominated bis-sulfimide with a diphosphine. The
reaction chosen was that of 1,4-(PhSNBr)2C6H4 with 1,4-
(Ph2P)2(C6H4) in the hope of generating the structure shown
in Scheme 1. The reaction was performed using high dilution
conditions in order to suppress the formation of polymeric spe-
cies. After removal of the solvent, a sticky solid resulted for
which 31P NMR revealed a mixture with a strong peak at
36.6 ppm, a shift similar to those found in the other S–N–P
compounds. Although this species could still be construed as
polymeric, the high solubility and mass spectrometry of this
Fig. 2 The cation in 2. Selected bond lengths and angles (see text
˚
also): N(1)–S(1) 1.605(6), N(1)–P(1) 1.603(6) A; S(1)–N(1)–P(1)
Scheme 1
125.2(4)ꢂ.
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
960
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6

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4 can be readily crystallised. The X-ray crystal structure of this
material reveals (Fig. 4) the desired mono-substituted thio-
ether crown, with the sulfoniosulfimidium unit exhibiting an
S–N–S angle of 108.55(10)ꢂ and S–N distances of 1.6433(17)
˚
˚
A and N–S(crown) 1.6559(17) A. Interestingly, the latter dis-
tance is almost identical to the S–N distance in the cation
{[9-ane]S3(NH2)}þ ([1.642(2) A].
˚
9
1
The H NMR of 4 shows the thia-crown protons as three
pairs of signals in an AB pattern each consisting of eight-line
multiplets. Three signals are observed in the aliphatic region
of the 13C NMR spectrum, consistent with the solid-state
structure not being retained in solution. A similar effect was
noted in the case of {[9-ane]S2SNH2}þ.
Fig. 3 The crystal structure of the cation in 3. Selected bond lengths
˚
and angles (see text also): N(1)–S(1) 1.599(3), N(1)–P(1) 1.599(3) A;
S(1)–N(1)–P(1) 125.84(18)ꢂ.
Addition of further Ph2SNBr does not appear to result in
the addition of more Ph2SN units to the structure. This con-
trasts to the reaction of the crown with MSH during which
addition of two sulfimidium units was shown to be possible.
Presumably in this case the steric bulk of the phenyl groups
on the incoming units mitigates against addition of more
than one.
As noted above, 1,4-[PhSNBr]2C6H4 is readily prepared
from the corresponding free bis-sulfimide and just as this com-
pound reacts analogously to Ph2SNBr when treated with phos-
phines, it also reacts with [9-ane]S3 . Reaction of 2 equiv of the
crown with 1 equiv of the bis-sulfimide results in the formation
of [1,4-{[9-ane]S2S(NSPh)}2C6H4]Br2 , 5, in which a crown
unit is added to both sulfimide units of the starting material.
Unfortunately, even after conversion to the [BPh4]ꢁ salt we
have been unable to crystallise this material and obtain struc-
tural confirmation via X-ray crystallography.
Although a number of previous reports exist of reactions
between N-halosulfimides with sulfides, phosphines and ter-
tiary amines, there is, to the best of our knowledge, no report
of a reaction with selenides. In order to address this omission,
we investigated the reactivity of both Ph2SNBr and 1,4-
[PhSNBr]2C6H4 towards Ph2Se.
Reaction of Ph2SNBr with Ph2Se in CH2Cl2 results in the
formation of the N-seleniosulfimidium salt [Ph2SNSePh2]Br,
6, isolated as a colourless solid after removal of the solvent
and trituration with ether. It is noteworthy that this reaction
is significantly faster and more efficient than the corresponding
reaction with Ph2S (which is reported to occur at high tem-
peratures, though in our hands we have found even then that
the yield is low; this is one reaction that appears to be more
efficient using Ph2SNCl).
product suggested otherwise, the latter revealing the highest
peak at m/z 770, consistent with the tentative formulation.
Microanalysis of this product was, however, unsatisfactory,
thus conversion to the BPh4ꢁ salt was attempted and treatment
of the solid with Na[BPh4] in MeOH resulted in a solid that
can tentatively be formulated as cyclo-[(Ph)SNP(Ph)2-
C6H4P(Ph)2NS(Ph)C6H4][BPh4]2 , exhibiting only a single peak
in the 31P NMR at 35.6 ppm as well as a peak for the molecu-
lar ion in electrospray mass spectrometry. Unfortunately,
despite repeated attempts we have thus far been unable to
grow single crystals of this material and so ultimate confirma-
tion of the structure remains elusive.
Preparation of new N-sulfoniosulfimidium salts and the first
examples of N-seleniosulfimidium salts
While Ph2SNBr has been shown to react with simple organo
monosulfides, the analogous reactivity towards polysulfide sys-
tems has not been reported. Here we have gone some way
towards addressing this by investigating the ability of the bro-
mosulfimide to react with the thio-crown [9-ane]S3 (Scheme 2).
In part this was prompted by the fact that previous work in
this group resulted in a series of azasulfonium salts generated
by the reaction of [9-ane]S3 with the aminating agent O-mesi-
tylsulfonylhydroxylamine (MSH).9 In the course of such reac-
tions one or more of the sulfþur atoms of the crown were
=
converted through to S NH2 groups, indicating that this
crown is susceptible to sulfimidation.
Reaction of 9[ane]S3 with 1 equiv of Ph2SNBr in CH2Cl2
results in the formation of an oily solid after removal of the
solvent. Washing of the solid with ether eventually leaves a
white solid that analyses (CHN) as the desired product,
namely [9[ane]S3NSPh2]Br. Attempts to crystallise this product
have so far proved unsuccessful; upon conversion to the
[BPh4]ꢁ salt (by addition of Na[BPh4]), however, the product
The X-ray crystal structure of 6 (Fig. 5) reveals the
[Ph2SNSePh2]þ cation is disordered with the S and Se sites
partially occupied by both elements. This disorder, which
results from the symmetric nature of the molecule, has been
refined to give the relative occupancies of [Ph2SNSePh2]þ:
[Ph2SeNSPh2]þ as 83.2:16.8(2)%. This disorder makes it rather
difficult to compare the S–N and Se–N bond lengths as each
Fig. 4 The crystal structure of the cation of 4. Selected bond angles
(see text also): C(18)–S(2)–C(13) 105.94(9)ꢂ, C(14)–S(3)–C(15)
103.43(11)ꢂ, C(16)–S(4)–C(17) 105.03(11)ꢂ.
Scheme 2
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6
961

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disorder of the sulfur and selenium sites so the value of the
˚
Se–N bond length of 1.814(2) A is a true representation of
the bonding within these units.
The 77Se chemical shifts of compounds 6 and 7 are very simi-
lar (694 and 696 ppm, respectively), highlighting the similarity
in chemical environment in the two cases. It is worth noting
that unlike a number of other Se–N systems such as
(Me3SiNSN)2Se and (Me3Si)2N–Se–N(SiMe3)2 , neither 6 nor
7 appear to be significantly sensitive to air. Thus, samples of
6, for example, have been kept sealed (in air) in sample vials
for many months without significant discolouration.
Cyclisation reactions of 1,2-PhS(NH)C6H4SPh
Fig. 5 The crystal structure of 6.
Reaction of the monosulfimide 1,2-PhS(NH)C6H4SPh with
one equivalent of N-bromosuccinimide (Scheme 3) results in
the generation of a yellow solution analogous to that of
Ph2SNBr formed from Ph2SNH. This solution does decolour-
ise with time, indicative of intramolecular attack from the N-
bromosulfimide group on the sulfide unit. However, there are
two problems with the reaction as it stands: firstly, the time
taken for completion of the decolourisation appears very vari-
able, suggesting that factors not yet determined have a big
influence on this reaction time. Secondly, the bromide salt pro-
duced tends to form as an oil and while we have had some suc-
cess at growing single crystals, the yield of the latter is very
low, though X-ray crystallography (which we are not present-
ing formally here) does confirm the connectivity of the result-
ing ring system.
A far more satisfactory situation prevails if Na[BPh4] is
added to the reaction mixture in methanol. Now the decolour-
isation is instantaneous and the product, [1,2-(PhS)2(m-N)-
C6H4][BPh4], 8, precipitates. Crystallisation of this product
by ether vapour diffusion into CH2Cl2 solutions results in the
formation of two crystal types: colourless needles (8a) and col-
ourless plates (8b). X-Ray crystallography confirms that in
both cases the desired intramolecular cyclisation has taken
place, but they differ by the relative disposition of the phenyl
groups.
will have some character of the minor component. If we con-
sider the Se–N bond length, for example, the true value for this
bond will be longer than that observed as the partial sulfur
character will act to shorten the bond. The opposite is true
for the corresponding S–N bond length. Although the bond
lengths obtained from the crystal structure cannot be quoted
reliably, relative effects can be observed. The Se–N bond length
˚
within 6 is observed to be 1.832(3) A with the S–N bond at
ꢂ
˚
1.678(3) A and an S–N–Se angle of 107.61(15) . The sulfur
character means that the true Se–N bond is longer than this
value. Recent work by Chivers and Laitinen et al. revealed
10
˚
Se–N single bonds of 1.844(3) A within (Me3SiNSN)2Se,
˚
while single bond lengths of 1.827(5) and 1.869(2) A have been
also been noted in OSN–Se–NSO11 and (Me3Si)2N–Se–
N(SiMe3)2 ,12 respectively. The Se–N distance observed in 6
is thus within this single bond range, even after the shortening
effect of the sulfur character. Thus, within the SNSe unit we see
a significant degree of multiple bonding character for the S–N
bond but little for Se–N.
The 1H NMR spectrum of 6 in CDCl3 reveals a multiplet in
the aromatic region. Included in this are two distinct doublets
of doublets, most likely corresponding to the hydrogens in the
4-position from the sulfur and selenium. The 13C NMR spec-
trum reveals the expected eight different carbon environments,
corresponding to the four positions of the carbon atoms in the
phenyl rings attached to the sulfur and selenium.
In the analogous reaction of 1,4-(PhSNBr)2C6H4 with 2
equiv of Ph2Se, the expected bis-N-seleniosulfimide [1,4-
(PhSNSePh2)2C6H4]Br2 is isolated; subsequent conversion to
the [BPh4]ꢁ salt [1,4-(PhSNSePh2)2C6H4][BPh4]2 (7) allows
crystallisation. X-Ray crystallography reveals the structure
shown in Fig. 6 and confirms that both sulfimide units have
indeed reacted with the incoming selenides. In 7 there is no
The asymmetric unit of 8a contains 3 [1,2-(PhS)2(m–N)-
C6H4]þ cations, all of which contain the phenyl rings in an
‘‘anti’’ arrangement as shown in Fig. 7. The cations form
dimers by a close Nꢃ ꢃ ꢃS approach of 3.100, 3.141 and 3.181
˚
A, giving a four-membered ring with an angle of approxi-
mately 104ꢂ at the nitrogen and approximately 75ꢂ at the sulfur
Fig. 6 The crystal structure of the cation in 7. Selected bond lengths
˚
and angles; N(1)–S(1) 1.637(2), N(1)–Se(1) 1.814(2) A; S(1)–N(1)–Se(1)
109.35(11)ꢂ.
Scheme 3 The cyclisation reaction of 1,2-PhS(NH)C6H4SPh with
N-bromosuccinimide.
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
962
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6

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Conclusion
The isolation of compounds 1–3 confirms that the basic reac-
tion of phosphines with bromosulfimides can be extended to
diphosphines and bis-sulfimides; the results also indicate that
such reactions may be adapted to generate new cyclic species
of which cyclo-[(Ph)SNP(Ph)2C6H4P(Ph)2NS(Ph)C6H4][BPh4]2
is the first example. As noted in the text we have yet to confirm
the cyclic structure of this material by X-ray crystallography,
though work towards solving this problem is under way. The
suggested structure (Scheme 1), if ultimately confirmed, will
raise the possibility of isolation of a series of variations upon
this structure, including a range of variations in ring size and
of substituents.
The isolation of 4 and 5 constitutes a rare example of
post ring-closure derivatisation of a thio-ether crown system
and raises the possibility of using such reactions either as
linking mechanisms or as a means of introducing pendant
arm coordinating groups into the system. The latter would
require the preparation of derivatised versions of Ph2SNBr
containing potentially coordinating groups; we have already
gone some way to addressing this by formation of hydroxy
substituted sulfimides and many more examples should be
possible.
The isolation of 6 and 7 represents a simple route into a
new class of Se–N species; in this context it is also important
to note that unlike many other Se–N compounds the pro-
ducts are neither explosive nor air-sensitive. Finally, the iso-
lation of the cyclic product 8 illustrates a new route to SN
heterocycles. Again, the potential for derivatisation to this
structure should mean that this intramolecular ring closure
technique should provide a route to many more interesting
structures.
Fig. 7 One of the two unique dimers formed by the cations in 8a.
Selected bond lengths and angles (see text also): N(2)–S(3) 1.618(3),
˚
N(2)–S(4) 1.669(3), N(3)–S(5) 1.609(3), N(3)–S(6) 1.677(3) A; S(3)–
N(2)–S(4) 113.35(14)ꢂ, S(5)–N(3)–S(6) 113.25(14)ꢂ. For the other
˚
cation: N(1)–S(1) 1.617(3), N(1)–S(2) 1.663(3) A, S(1)–N(1)–S(2)
114.36(16)ꢂ.
[the cations containing N(1) dimerise with themselves and
those containing N(2) and N(3) interact with each other].
The asymmetric unit of 8b contains a single [1,2-(PhS)2(m–
N)C6H4]þ cation and one [BPh4]ꢁ anion. In contrast to 8a,
the phenyl rings are arranged in a ’’syn’’ position as shown
in Fig. 8(a). There are no significant Nꢃ ꢃ ꢃS interactions but
there is a weak C–Hꢃ ꢃ ꢃN hydrogen bond (Cꢃ ꢃ ꢃN distance of
ꢂ
˚
3.298 A, C–Hꢃ ꢃ ꢃN angle of 144.8 ) to a phenyl hydrogen. This
interaction links the cations into a 1-D chain as shown in Fig.
8(b). [If the cations are viewed along an S–C bond (a C of the
terminal phenyl rings) the other ring is at 180ꢂ in 8a and 0ꢂ in
8b, hence the ‘‘anti’’ and ‘‘syn’’ terminology.]
Experimental
General
Ph2SNBr,5 1,4-{PhS(NH)}2C6H4 ,3 1,2-C6H4(PhS)(PhSNH).
H2O,3 1,4-(PPh2)2C6H4
and O-mesitylenehydroxlyamine
13
(MSH)3 were prepared according to the literature methods.
Diethyl ether was dried over sodium/benzophenone and
dichloromethane over CaH2 .
Microanalyses were performed by the Loughborough
Departmental Service, IR spectra recorded on a Perkin–Elmer
2000 spectrometer and NMR on a Bruker AC250 spectro-
meter. FAB mass spectra were recorded on a JEOL JMS
SX102 (positive ion mode) and ES-MS were performed by
the EPSRC Mass Spectrometry Service, University Of Wales,
Swansea.
Syntheses
[1,2-(Ph2PNSPh2)2C2H4]Br2 (1). A solution of Ph2SNBr
(873 mg, 3.11 mmol) in toluene (5 ml) was treated with dppe
(621 mg, 1.56 mmol) in an equal volume of the same solvent,
added with stirring. A white precipitate appeared immediately;
this was filtered and washed with diethyl ether (4 ꢄ 5 ml). The
resulting white solid was recrystallised from CH2Cl2–Et2O.
Yield 1.24 g, 76%. CHN: Found C 62.3, H 4.2 N 2.6%; Calcd
for C50H44N2Br2P2S2 : C 62.8, H 4.6, N 2.9%. IR (cmꢁ1) 1119,
1091 n(P–N). FAB-MS m/z 798 (M ꢁ 2Br)þ. 1H NMR
(CDCl3) d 7.43–7.79 (20H, m), 3.13 (4H, m).13C NMR
(CDCl3) d 137.3, 134.4, 132.4, 132.2, 130.4, 130.0, 126.9,
123.7, 122.7, 21.1. 31P NMR (CDCl3) d 40.4 (s).
Fig. 8 (a) The structure of the cation in 8b showing the syn arrange-
ment of the phenyl rings. (b) The extended 1-D chain formed via a
weak C–Hꢃ ꢃ ꢃN hydrogen bond. Selected bond lengths and angles
[1,4-(Ph2PNSPh2)2(C6H4)][Br]2 (2). A solution of Ph2SNBr
(178 mg, 0.64 mmol) in toluene (15 ml) was treated with
1,4-(Ph2P)2(C6H4) (142 mg, 0.32 mmol) in the same solvent
˚
(see text also): N(1)–S(1) 1.6494(17), N(1)–S(2) 1.6501(19) A; S(1)–
N(1)–S(2) 111.84(10)ꢂ.
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6
963

View Article Online
(10 ml). After stirring overnight, an off-white solid had precipi-
tated which was filtered, washed with toluene (10 ml) and
diethyl ether (2 ꢄ 10 ml) and then recrystallised from
CH2Cl2–ether. Yield 308 mg, 96%. CHN Calcd for
C54H44N2Br2P2S2ꢃ1.5CH2Cl2 : C 58.8, H 4.2, N 2.5%; Found
C 59.0, H 4.7 N 2.1%. IR (cmꢁ1) 843m n(S–N), 1112s, 1064s
n(P–N). FAB-MS m/z 927 (M ꢁ Br)þ. 1H NMR (CDCl3) d
7.44–7.95 (40H, m). Dichloromethane is also evident in the
1H NMR spectra of 2 at 5.27 ppm and integrates to approxi-
mately 3 protons. 13C NMR (CDCl3) d 136.8, 134.7, 133.6,
133.4, 132.8, 130.6, 130.1, 129.3, 126.7, 124.1, 123.1. 31P
NMR (CDCl3) d 33.2 (s).
1088 (M ꢁ BPh4)þ, 770 (M ꢁ 2BPh4 þ 2H)þ, 384 (M ꢁ 2BPh4)2þ
.
31P NMR (CD3CN) d 35.6.
[9[ane]S3NSPh2][BPh4] (4). A solution of 9[ane]S3 (31 mg,
0.17 mmol) in toluene (5 ml) was added to Ph2SNBr (48 mg,
0.17 mmol) dissolved in an equal volume of the same solvent.
After stirring overnight, the solvent was removed under
reduced pressure to give a yellow oil, which was triturated with
Et2O (20 ml). A white precipitate formed that was filtered and
washed with Et2O, leaving [9[ane]S3NSPh2]Br as an off-white
solid after drying. Yield 55 mg, 70%. CHN Calcd for
C18H22NBrS4 : C 46.9, H 4.8, N 3.0%; Found C 46.4, H 4.7
This material was converted to the analogous [BPh4]ꢁ salt
by treating the material (151 mg, 0.15 mmol) dissolved in
MeOH (10 ml) with Na[BPh4] (107 mg, 0.31 mmol) in MeOH
(5 ml). A colourless solid precipitated immediately. Stirring
was continued for a further 15 min. The solid was collected
by filtration, washed with MeOH (10 ml) and then Et2O (10
ml) and dried under vacuum. Yield 202 mg, 91%. CHN Calcd
for C102H84B2N2P2S2 : C 82.5, H 5.7, N 1.9%; Found C 82.3, H
5.3 N 1.9%. X-Ray quality crystals of this material were
obtained by recrystallisation from acetonitrile–diethyl ether.
N
3.3%. IR (cmꢁ1
) 920br n(S–N). FAB-MS m/z 380
(M ꢁ Br)þ. 1H NMR (CDCl3) d 7.53–7.69 (10H, m), 4.27
(2H, m), 3.64 (2H, m), 3.27 (2H, m), 3.03 (2H, m), 2.91 (2H,
m), 2.80 (2H, m). 13C NMR (CDCl3) d 136.3, 131.7, 129.2,
126.6, 51.4, 34.0, 26.3.
This material was converted to the analogous [BPh4]ꢁsalt by
treating the material (80 mg, 0.17 mmol) dissolved in MeOH
(5 ml) with Na[BPh4] (60 mg, 0.18 mmol) in MeOH (5 ml).
A white solid precipitated immediately, which was filtered,
washed with MeOH and Et2O (10 ml of both), then recrystal-
lised from acetonitrile–diethyl ether to produce crystals of
X-ray quality. Yield 56 mg, 45%. CHN Calcd for
C42H42NBS4ꢃMeCN: C 71.4, H 6.0, N 3.8%; Found C 71.4,
H 6.0 N 3.8%. IR (cmꢁ1) 927br n(S–N). ES-MS (acetone)
m/z 380 (M ꢁ BPh4)þ. 1H NMR (CDCl3) d 7.76 (4H, m),
7.64 (6H, m) 7.30 (8H, m) 7.02 (8H, m), 6.87 (4H, m), 4.35
(2H, m), 3.70 (2H, m), 3.33 (2H, m), 3.10 (2H, m), 3.00 (2H,
m), 2.85 ppm (2H, m). 13C NMR (CDCl3) d 136.8, 135.4,
132.7, 130.0, 126.6, 125.3, 121.4, 117.0, 52.1, 34.6, 26.7.
[1,4-(PhS{NSPPh3})2C6H4]Br2 (3). 1,4-{PhS(NH)}2C6H4
(425 mg, 1.31 mmol) was dissolved in degassed MeOH (15
ml) and cooled in ice. N-Bromosuccinimide (487 mg, 2.74
mmol) was dissolved in degassed acetone (10 ml) and added
to the MeOH solution. The resulting yellow precipitate of
1,4-[PhSNBr]2C6H4 was collected by filtration, washed with
MeOH, then acetone and dried in vacuo. Yield 573 mg, 90%.
CHN Calcd for C18H15Br2N2S2 : C 44.8, H 2.9, N 5.8%;
Found C 44.8, H 3.3 N 5.6%. IR (cmꢁ1) 867br n(S–N).
A suspension of this material (178 mg, 0.29 mmol) in
degassed CH2Cl2 (15 ml) was treated with PPh3 (154 mg,
0.59 mmol) added as a solid with stirring in a single portion.
After 5 min of stirring the initial suspension had completely
dissolved, giving a colourless solution that was stirred over-
night. The resulting slightly cloudy solution was filtered
through Celite and the volume of the filtrate was reduced to
ca. 3 ml. The addition of diethyl ether (40 ml) with stirring
gave a colourless solid. After filtration the material was
washed with Et2O, leaving a slightly off-white solid. Yield
267 mg, 93%. CHN Calcd. for C54H44N2Br2P2S2 : C 64.5, H
4.4, N 2.8%; Found C 64.4, H 4.0, N 2.6%. IR (cmꢁ1) 844m
n(S–N), 1113s, 1088s n(P–N). FAB-MS m/z 927 (M ꢁ Br)þ.
1H NMR (CDCl3) d 7.98–8.02 (6H, m), 7.48–7.62 (48H m).
13C NMR (CDCl3) d 141.7, 136.9, 134.3, 1133.3, 132.6,
130.6, 129.9, 128.6, 127.0, 125.0, 124.4. 31P NMR (CDCl3) d
34.8 (s).
[1,4-{[9-ane]S2S(NSPh)}2C6H4][BPh4]2 (5). 1,4-{PhS(NBr)}2-
C6H4 (101 mg, 0.21 mmol) was suspended in dry methanol
and 9[ane]S3 (77 mg, 0.43 mmol) was added as a solid in a
single portion. The suspended mixture was stirred overnight
(16 h) giving a very pale yellow, clear solution. To this was
added solid Na[BPh4] (147 mg, 0.43 mmol) and the mixture
was stirred for 20 min. The resulting precipitate was collected
by filtration, washed with MeOH (3 ꢄ 5 ml) and Et2O
(3 ꢄ 10 ml), then dried in vacuo overnight. Yield 181 mg,
65%. CHN Calcd for C78H78B2N2S8 : C 70.9, H 5.9, N
2.1%; Found C 70.4, H 5.8 N 2.2%. IR (cmꢁ1) 915w n(S–N).
ES-MS (MeCN) m/z 1001 (M ꢁ BPh4)þ, 341 (M ꢁ 2BPh4)2þ
.
1H NMR (CD2Cl2) d 7.41–7.19 (28H, m), 6.87 (18H, m) 6.77
(8H, m), 3.87 (2H, m), 3.78 (2H, m), 3.23 (4H, m), 2.93–2.43
(16H, m). 13C NMR (CD2Cl2) d 136.3, 136.0, 134.6, 131.5,
131.4, 129.9, 128.9, 128.4, 126.4, 126.3, 122.5, 52.9, 52.1,
36.1, 35.9, 28.0, 27.9.
Unfortunately, unlike other instances where the [BPh4]ꢁ salt
was prepared, the introduction of the anion did not increase
the ease of crystallisation and no crystals of X-ray quality
could be generated.
Reaction of 1,4-(PhSNBr)2C6H4 with 1,4-(Ph2P)2(C6H4). A
solution of 1,4-(PPh2)2C6H4 (11 mg, 0.025 mmol) in dry
CH2Cl2 (60 ml) was added dropwise with into dry CH2Cl2
(250 ml) containing 1,4-[PhSNBr]2C6H4 (12 mg, 0.025 mmol,
prepared as above). After stirring for 12 h, more 1,4-
[PhSNBr]2C6H4 (12 mg, 0.025 mmol) was added to the reac-
tion mixture. Another solution of the diphosphine was added
dropwise to the reaction and stirred for a further 12 h. This
was repeated twice more. The solvent was then removed under
reduced pressure, leaving a white residue that was extracted
with MeOH (3 ꢄ 10 ml), the combined extracts filtered and
then treated with Na[BPh4] (70 mg, 0.2 mmol) in MeOH (5
ml). A white precipitate immediately formed and after 1 h
stirring this was filtered and washed with MeOH, CH2Cl2
and Et2O (10 ml of each) and dried. Yield 28 mg, 20%.
CHN: Found C 79.6, H 5.4, N 2.1%; Calcd For C96H78
[Ph2SNSePh2]Br (6). A solution of Ph2SNBr (850 mg, 3
mmol) in CH2Cl2 (5 ml) was treated with a solution of Ph2Se
(710 mg, 3 mmol) in CH2Cl2 (5 ml), added dropwise with stir-
ring. The resulting mixture was allowed to stir overnight after
which time the solvent was removed in vacuo. After washing
with Et2O (2 ꢄ 20 ml) and drying in vacuo, 6 was obtained
as a white solid. Yield 1.39 g, 89%. CHN Calcd for
C24H20NBrSSe: C 56.1, H 3.9, N 2.7%; Found C 55.2, H 3.7
N 2.7%. IR (cmꢁ1) 871s n(S–N), 643m n(Se–N). FAB-MS
1
m/z 434 (M ꢁ Br)þ. H NMR (CDCl3) d 7.35–7.50 (m, 12H)
7.61–7.65 (m, 4H) 7.87–7.89 ppm (m, 4H). 13C NMR (CDCl3)
d 127.9, 129.6, 130.3, 130.4, 132.4, 132.8, 137.5, 138.87. 77Se
NMR (CDCl3) d 677.9 (s).
N2B2P2S2ꢃ0.5CH2Cl2 : C 80.0, H 5.5, N 1.9%. IR (cmꢁ1
)
916w n(S–N), 1069s, 1118s n(P–N). ES-MS (CH3CN) m/z
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
964
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6

View Article Online
Table 1 X-Ray crystallographic data
1
2
3
4
6
7
8a
8b
Formula
C50H44Br2N2P2S2ꢃ C102H84B2N2P2S2 C54H44Br2N2P2S2ꢃ
C
42H42BNS4ꢃ
C
24H20BrNSSe C90H74B2N2S2Se2 C126H102B3N3S6ꢃ
C42H34BNS2ꢃ
2CH2Cl2
1128.60
Monoclinic
P21/c
2CH3OH
1070.88
Monoclinic
P21/c
CH3CN
740.87
C4H10Oꢃ0.5CH2Cl2 0.5CH2Cl2
M
1485.39
Monoclinic
P21/n
513.34
Monoclinic
P21/n
1427.17
Monoclinic
P21/c
1999.48
Triclinic
¯
P1
670.10
Monoclinic
P21/c
Crystal system
Space group
Triclinic
¯
P1
˚
a/A
14.1746(7)
14.7287(7)
12.9914(6)
90
9.984(2)
28.483(6)
13.850(3)
90
9.4252(5)
14.7382(8)
18.3414(10)
90
10.0080(17)
10.0428(17)
20.281(3)
103.872(3)
96.430(3)
95.884(3)
1948.7(6)
2
8.0966(5)
15.4700(9)
16.7219(10)
90
11.4390(7)
16.4905(10)
19.0299(11)
90
15.4453(9)
17.0255(10)
20.8544(12)
91.183(2)
103.617(2)
93.015(2)
5319.3(5)
2
10.1131(7)
10.9151(8)
31.609(2)
90
˚
b/A
˚
c/A
a/ꢂ
b/ꢂ
g/ꢂ
107.527(2)
90
92.243(2)
90
95.367(2)
90
97.160(2)
90
102.904(2)
90
96.854(2)
90
3
˚
U/A
2586.3(2)
2
1.954
3935.8(14)
2
0.161
2536.6(2)
2
1.787
2078.2(2)
4
3.840
3499.0(4)
2
1.167
3464.2(4)
4
0.263
Z
m/mmꢁ1
Measured
reflections
0.278
17238
1.248
38966
22509
22487
21995
17434
30423
17069
Indep. reflections 6250
5141
2358
6139
4279
8974
6057
4939
4473
8465
5680
18627
10122
6085
4271
Obs. reflections
[F2 > 2s(F2)]
Rint
5433
0.0205
0.0269
0.0784
0.1715
0.0854
0.2870
0.0396
0.0507
0.1455
0.0304
0.0452
0.1119
0.0328
0.0380
0.0871
0.0329
0.0389
0.1046
0.0460
0.0548
0.1340
0.0354
0.0409
0.0999
R [F2 > 2s(F2)]
wR2 (all data)
[1,4-(PhSNSePh2)2C6H4][BPh4]2 (7). A solution of 1,4-
[PhSNBr]2C6H4 (50 mg, 0.1 mmol) in CH2Cl2 (10 ml) was trea-
ted with a solution of Ph2Se (55 mg, 0.24 mmol) in CH2Cl2 (10
ml) added slowly, with stirring. After stirring for a further 5
days, the CH2Cl2 was removed under reduced pressure and
the residue stirred overnight with Et2O (10 ml). After filtration
the resulting solid was extracted into MeOH (10 ml), the solu-
tion filtered and then treated with a solution of Na[BPh4](70
mg, 0.22 mmol) in MeOH (5 ml) with stirring. The resulting
white precipitate was filtered, washed with MeOH and Et2O
(10 ml of each) and then dried in vacuo, to give 7 as a white
solid. Yield 71 mg, 50%. CHN Calcd for C90H74N2B2S2Se2 :
C 75.7, H 5.2, N 2.0%; Found C 76.0, H 5.1 N 2.0%. IR
(cmꢁ1) 878m n(S–N), 643m n(Se–N). ES-MS (acetone) m/z
structural aspects of these complexes are described below
and the crystal structure data is presented in Table 1.y
6. The [Ph2SNSePh2]þ cation is disordered with the S and Se
sites partially occupied by both elements. This disorder has
been refined to give the relative occupancies of [Ph2SNSePh2]þ:
[Ph2SeNSPh2]þ of 83.2:16.8(2)%.
7. The asymmetric unit contains half a [1,4-(PhSNSePh2)2-
C6H4]þ cation and a [BPh4]ꢁ anion. The cation is disordered
with alternative positions for the S and Se atoms [refined occu-
pancies of 91.61:8.39(17)%]. This disorder has been modelled
with geometric and displacement parameter restraints applied.
It is clear that the minor disorder extends throughout the S–N–
Se section of the molecule and probably also includes the phe-
nyl and C6H4 rings. However, due to the low occupancy, only
the S and Se sites were modelled as disordered.
1107 (M ꢁ BPh4)þ, 395 (M ꢁ 2BPh4)2þ
DMSO) d 695.5.
.
77Se NMR (d6-
[1,2-(PhS)2(l-N)C6H4][BPh4] (8).
A
solution of 1,2-
PhS(NH)C6H4SPhꢃH2O (0.25 g, 0.76 mmol) in MeOH (15
ml) was treated with N-bromosuccinimide (0.136 g, 0.76 mmol)
added as a solid with stirring. The resulting yellow solution
was stirred for 10 min after which time solid Na[BPh4]
(0.261 g, 0.76 mmol) was added with vigorous stirring, imme-
diately generating a white precipitate. After further stirring for
10 min the solid was filtered and washed with cold MeOH
(5 ml) and then Et2O (20 ml) before drying in vacuo. Yield
0.326 g, 86%. CHN Calcd for C42H34BNS2 : C 80.4, H 5.4,
N 2.2%; Found C 80.3, H 5.3, N 2.1%. IR (cmꢁ1) 908w
n(S–N). ES-MS (MeOH) m/z 308 (M ꢁ BPh4). 1H NMR
(CDCl3) d 9.10 (dd, 1H), 8.64 (dd, 1H), 8.01 (dd, 1H), 7.92
(d, 2H), 7.73 (dd, 1H), 7.50 (m, 4H), 7.13 (d, 2H), 7.06
(t, 2H). 13C NMR (CDCl3) d 137.4, 137.1, 136.7, 134.5,
134.4, 134.1, 130.7, 129.7, 129.6, 128.2, 127.8, 127.5.
8. Both 8a and 8b contain diffuse solvent molecules that
could not be modelled using a point atom model. The PLA-
TON squeeze program15 was used to model this as half a
CH2Cl2 molecule per asymmetric unit for each structure.
Acknowledgements
The authors are grateful to the EPSRC Mass Spectrometry
Service, University Of Wales Swansea, and to the EPSRC
for PDRA support (SMA, LMG and KEH)
References
1
See, for example: A. V. Makarycheva-Mikhailova, N. A. Bokach,
V. Y. Kukushkin, P. F. Kelly, L. M. Gilby, M. L. Kuznetsov,
K. E. Holmes, M. Haukka, J. Parr, J. M. Stonehouse, M. R. J.
Elsegood and A. J. L. Pombeiro, Inorg. Chem., 2003, 42, 301
and references therein.
Crystallography
Data for all complexes was collected at 150 K with a Bruker
SMART AXS 1000 CCD diffractometer and Mo-Ka radiation
2
M. R. J. Elsegood, K. E. Holmes, P. F. Kelly, E. J. MacLean, J.
Parr and J. M. Stonehouse, Eur. J. Inorg. Chem., 2003, 120.
˚
(l ¼ 0.71073 A). All structures were solved by direct methods
and were refined by full-matrix least-squares methods on F2.
All hydrogens were placed in geometrical positions using
a riding model. Programs used were Bruker SMART,14a
SAINT,14a SHELXTL14b and local programs. Any unusual
y CCDC reference numbers 236754–236761. See http://www.rsc.org/
suppdata/nj/b3/b316850f/ for crystallographic data in .cif or other
electronic format.
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6
965

View Article Online
3
4
5
M. R. J. Elsegood, K. E. Holmes, P. F. Kelly, J. Parr and J. M.
Stonehouse, New. J. Chem., 2002, 26, 202.
P. F. Kelly, K. G. Parker, M. A. Rodiel and A. M. Z. Slawin,
J. Organomet. Chem., 2001, 623, 120.
For example: N. Furukawa, T. Yoshimura and S. Oae, Tetrahe-
dron Letters, 1973, 2113; N. Furukawa, T. Yoshimura, T.
Akasaka and S. Oae, Tetrahedron, 1977, 33, 1061.
N. Furukawa, Y. Nishikawa, Y. Matsuura, M. Kakudo, T.
Akasaka and S. Oae, Chem. Lett., 1978, 447.
A. M. Griffin and G. M. Sheldrick, Acta Crysallogr., Sect. B,
1975, 31, 893.
R. Reck, L. Zsolnai, G. Huttner, S. Herzberger and J. C. Jochims,
Chem. Ber., 1982, 115, 2981.
M. R. J. Elsegood, L. M. Gilby, K. E. Holmes and P. F. Kelly,
Can. J. Chem., 2002, 18, 1410.
10 J. Konu, A. Maaninen, K. Paananen, P. Ingman, R. S. Laitinen,
T. Chivers and J. Valkonen, Inorg. Chem., 2002, 41, 1430.
11 A. Haas, J. Kasprowski, K. Angermund, P. Betz, C. Kruger,
Y.-H. Tsay and S. Werner, Chem. Ber., 1991, 124, 1895.
12 M. Bjo¨rgvinsson, H. W. Roesky, F. Pauer, D. Stalke and G. M.
Sheldrick, Inorg. Chem., 1990, 29, 5140.
13 R. A. Baldwin and R. M. Washburn, J. Org. Chem., 1965, 30,
3860.
14 (a) SMART and SAINT software for CCD diffractometers, Bruker
AXS, Inc., Madison, WI, USA, 1994; (b) G. M. Sheldrick,
SHELXTL user manual, version 5, Bruker AXS, Inc., Madison,
WI, USA, 1994.
6
7
8
9
15 A. L. Spek, PLATON, A Multipurpose Crystallographic Tool,
Utrecht University, Utrecht, The Netherlands, 2003.
T h i s j o u r n a l i s Q 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 a n d t h e
C e n t r e N a t i o n a l d e l a R e c h e r c h e S c i e n t i f i q u e 2 0 0 4
966
N e w . J . C h e m . , 2 0 0 4 , 2 8 , 9 5 9 – 9 6 6