Preparation of Organic Polysulfanes R2Sn (n = 5, 7, 8, 9) from Sulfenyl Chlorides, RSCl, and Transition Metal Polysulfido Complexes

Article abstract of DOI:10.1002/(SICI)1099-0682(200005)2000:5<921::AID-EJIC921>3.0.CO;2-2

The preparation of seven novel organic polysulfanes is reported. Bis(n-octyl)heptasulfane R2S7 1 is formed upon reaction of RSCl with [Cp2TiS5], while the corresponding nonasulfane R2S9 2 is obtained by reaction of RSSCl with [Cp2TiS5]. The bis(n-octyl)pe

Full text of DOI:10.1002/(SICI)1099-0682(200005)2000:5<921::AID-EJIC921>3.0.CO;2-2

FULL PAPER
Sulfur Compounds, 212[‡]
Preparation of Organic Polysulfanes R2Sn (n ؍ 5, 7, 8, 9) from Sulfenyl
Chlorides, RSCl, and Transition Metal Polysulfido Complexes
Ralf Steudel,*[a] Karin Hassenberg,[a] Vera Münchow,[a] Oliver Schumann,[a] and
Joachim Pickardt[a]
Keywords: Sulfur / Titanium / Zinc / Polysulfido complexes / Sulfur heterocycles / Polysulfides / Polysulfanes / Sulfenyl
chlorides
The preparation of seven novel organic polysulfanes is re-
known 1,2,3,4,5-benzopentathiepin C6H4S5 6, with [Cp2TiS5]
ported. Bis(n-octyl)heptasulfane R2S7 1 is formed upon reac- to give the novel 1,2,3,4,5,6,7-benzoheptathionin C6H4S7 7,
tion of RSCl with [Cp2TiS5], while the corresponding nonas- and with [(TMEDA)ZnS6] to give the novel 1,2,3,4,5,6,7,8-
ulfane R2S9 2 is obtained by reaction of RSSCl with [Cp2TiS5].
The bis(n-octyl)pentasulfane R2S5 3 is obtained from RSCl
and [(CpЈ2TiCl)2S3] by transfer of the S3 ligand at 20 °C. The
new alkyl polysulfanes 1–3 have been obtained in quantitat-
ive yields. They are liquids at 20 °C, having freezing points
below –50 °C, but do not form mesogenic phases. Reactions
of [Cp2TiS5] with 2-naphthyl- and 4-chlorophenyl sulfenyl
chloride furnish the corresponding heptasulfanes 4 and 5, re-
benzooctathiecin C6H4S8 8. The cyclic polysulfanes 6–8 are
solids at 20 °C and have been recovered in yields of 60–83%.
The orthorhombic structure of 1,2-C6H4S7 has been investig-
ated by single-crystal X-ray diffraction analysis. The molec-
ules are found to be located at sites of Cs symmetry and the
motif of the C2S7 heterocycle is +–+–+–+–, with the torsion
angle of zero at the carbon–carbon bond. The three internu-
clear SS distances measure 205.0(1), 203.7(1), and 205.7(1)
spectively, which are solids at 20 °C. 1,2-Benzodisulfenyl pm.
chloride C6H4(SCl)2 reacts with [(CpЈ2TiCl)2S3] to give the
Introduction
pounds are allowed to react with titanocene pentasulfide,
chain-like polysulfanes with up to nine sulfur atoms may be
generated (Equation 3 and 4; Cp ϭ η5-C5H5):[7,8]
Sulfur-rich organic polysulfanes R2Sn (n Ͼ 2) may be
synthesized by a variety of methods starting from either
thiols, sulfenyl chlorides, elemental sulfur, sulfanes (H2Sn),
chlorosulfanes (SnCl2), ionic polysulfides (e.g. Na2Sn), or
other sulfur compounds.[1] In most cases, mixtures of poly-
sulfanes of varying chain length n are obtained, which have
to be separated by repeated crystallization or by chromato-
graphy. Such separations have to be conducted under mild
conditions owing to the thermal and thermodynamic in-
stability of the longer-chain polysulfanes, which tend to
equilibrate with species of other chain lengths or to split off
S8, S7, or S6 (Equation 1 and 2):[2]
2 CCl3SCl ϩ [Cp2TiS5] Ǟ (CCl3)2S7 ϩ [Cp2TiCl2]
2 iPrOSSCl ϩ [Cp2TiS5] Ǟ (iPrO)2S9 ϩ [Cp2TiCl2]
(3)
(4)
In a similar fashion, bifunctional organic sulfenyl chlor-
ides and chlorodisulfanes have been treated with titanocene
pentasulfide or similar complexes, thereby generating cyclic
sulfur-rich polysulfanes with up to 11 sulfur atoms (Equa-
tion 5 and 6):[9,10,11]
1,2-C2H4(SCl)2 ϩ [Cp2TiS5] Ǟ C2H4S7 ϩ [Cp2TiCl2]
(5)
1,2-C7H10(SCl)(SSCl) ϩ [Cp2TiS5] Ǟ C7H10S8 ϩ [Cp2TiCl2] (6)
2 R2Sn Ǟ R2Snϩx ϩ R2Sn–x
R2Sn Ǟ R2Sn–8 ϩ S8 (n Ͼ 8)
(1)
(2)
A relatively new titanocene polysulfide complex is
[CpЈ2Ti(Cl)–S3–(Cl)TiCpЈ2],[12] which reacts with sulfenyl
chlorides as an S3 group transfer reagent (Equation 7 and
8; CpЈ ϭ CH3C5H4):[13]
In recent years, the enormous potential of titanocene
polysulfide complexes for the synthesis of novel homocyclic
and heterocyclic organic and inorganic sulfur compounds
has been demonstrated.[3,4,5,6] Using these reagents, a large
number of interesting sulfur-rich species have been pre-
pared, for which no synthetic route had hitherto been avail-
able. When organic sulfenyl chlorides or related SCl com-
C10H12(SCl)2 ϩ [(CpЈ2TiCl)2S3] Ǟ C10H12S5 ϩ 2 [CpЈ2TiCl2] (7)
C10H12(SCl)(SSCl) ϩ [(CpЈ2TiCl)2S3] Ǟ
C10H12S6 ϩ 2 [CpЈ2TiCl2] (8)
In this work, we report the synthesis of five chain-like
and three cyclic organic polysulfanes with between 5 and 9
sulfur atoms. In the case of the chain-like species, we used
alkyl as well as aryl substituents. The n-octyl substituent
was employed in the hope that the rather long chains of (n-
[‡]
Part 211: A. H. Otto, R. Steudel, Eur. J. Inorg. Chem., in print.
[a]
Institut für Anorganische und Analytische Chemie, Sekr. C2,
Technische Universität Berlin,
D-10623 Berlin, Germany
Fax: (internat.) ϩ 49-(0)30/314-26529
E-mail: steudel@schwefel.chem.tu-berlin.de
Eur. J. Inorg. Chem. 2000, 921Ϫ928
WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
1434Ϫ1948/00/0505Ϫ0921 $ 17.50ϩ.50/0
921

R. Steudel, K. Hassenberg, V. Münchow, O. Schumann, J. Pickardt
FULL PAPER
octyl)2Sn would result in a high degree of anisotropy and the natural logarithm of the capacity factor (ln kЈ), which
consequently in mesogenic properties. The aryl groups 4- is calculated from the retention time. This has previously
chlorophenyl and 2-naphthyl were used in the expectation been demonstrated for other polysulfanes bearing alkyl and
that readily crystallizable products suitable for X-ray crys- aryl substituents.[10,11,13,17] On heating of the nonasulfane 2
tallographic analysis would be obtained. In the case of the at 80 °C for 30 min., decomposition occurred resulting in a
cyclic species, 1,2-substituted benzene was used for the same mixture of polysulfanes with up to 15 sulfur atoms. A plot
reason. A further aim of this work was to study the utility of ln kЈ versus the number of sulfur atoms nS for the bis(n-
of the zinc polysulfide chelate complex [(TMEDA)ZnS6] in octyl)polysulfanes formed in this reaction is shown in Fig-
the preparation of sulfur-rich organic heterocycles. This ure 1.
compound has previously been used to prepare inorganic
[14]
rings such as 1,2-Se2S6
and S14 (Equation 9).[15]
Results and Discussion
Aliphatic Polysulfanes[16]
Octylsulfenyl chloride was prepared by chlorination of n-
octanethiol. Titanocene pentasulfide was found to react
with this sulfenyl chloride at temperatures below 0 °C in
carbon disulfide to quantitatively afford bis(n-octyl)hepta-
sulfane 1 (Equation 10; x ϭ 1). This compound is a viscous
red liquid at ambient temperature and has a freezing point
of –60 °C.
Figure 1. Dependence of the chromatographic retention times of
the bis(n-octyl)polysulfanes (C8H17)2Sn (n ϭ 2–15) on the number
of sulfur atoms nS; here, ln kЈ is plotted against nS [kЈ ϭ (tr – t0)/
t0; t0 ϭ dead time, tr ϭ retention time]
Table 1. Retention data (retention times tR, capacity factors kЈ, and
retention index values RS) of the homologous series (C8H17)2Sn
(n ϭ 2–15)
2 nC8H17SxCl ϩ [Cp2TiS5] Ǟ (nC8H17)2S5ϩ2x ϩ [Cp2TiCl2] (10)
Reaction of n-octanethiol with dichlorosulfane gives n-
octylchlorodisulfane, which reacts with titanocene pentasul-
fide under the same experimental conditions as above to
yield the orange bis(n-octyl)nonasulfane
2
(Equa-
tion 10; x ϭ 2). This product freezes to a glass at –52 °C.
Bis(n-octyl)pentasulfane 3, a yellow liquid with freezing
point –67 °C, was prepared by the reaction of n-octylsul-
fenyl chloride with bis[bis(methylcyclopentadienyl)chloro-
titanium]trisulfide [(CpЈ2TiCl)2S3] in carbon disulfide at low
temperatures (Equation 11; CpЈ ϭ CH3C5H4).
The chromatographic data and the retention indices
RS [18] derived therefrom are given in Table 1. The retention
indices are independent of the chromatographic system
used and can therefore be used for the identification of
these species in a similar manner as spectroscopic data.
The chromatograms of the pure products 1–3 showed nei-
1
Analyses by H-NMR and HPLC showed that the un- ther traces of other polysulfanes nor of sulfur homocycles,
usual red color of the heptasulfane 1 is not due to traces of the other products of the disproportionation of polysul-
titanocene pentasulfide or titanocene dichloride as might fanes according to Equations 1 and 2. The three liquid
be suspected. Bis(n-octyl)nonasulfane 2 is the most sulfur- bis(n-octyl)polysulfanes can be stored at –25 °C for several
rich of all selectively available diorganylpolysulfanes that is months without decomposition. After storage at ambient
liquid at ambient temperature.
temperatures for three days, HPLC analysis showed that
The lengths of the sulfur chains in these novel com- about 10% of the products had undergone dispropor-
1
pounds have been assessed not only by microanalysis, but tionation. The H- and 13C-NMR spectra of 1–3 did not
also by reversed-phase HPLC. A linear relationship exists reveal any unusual features. The proton signals exhibit a
between the number of sulfur atoms in the chain (nS) and very slight downfield shift with increasing number of sulfur
922
Eur. J. Inorg. Chem. 2000, 921Ϫ928

Sulfur Compounds, 212
FULL PAPER
Aromatic Polysulfanes
atoms, reflecting the increase in acidity of the sulfanes H2Sn
with increasing chain length n.[19]
Chain-Like Heptasulfanes[20]
The infrared spectra of 1–3, recorded at ambient temper-
atures, are almost identical. They show mainly the absorp-
tions of the n-octyl substituents, i.e. strong signals due to
the CH stretching modes in the range 2850–2960 cm–1 and
the CH2 bending modes between 1200 and 1470 cm–1. More
interesting are the SS stretching modes, which can best be
detected by Raman spectroscopy. The low-temperature
(–135 °C) Raman spectra exhibit, besides weak to strong
lines in the ranges 2700–3000 cm–1 and 1300–1500 cm–1 at-
tributable to the n-octyl substituents, several lines between
420 and 510 cm–1, which are characteristic of catenated sul-
fur. In this region, the spectrum of (nC8H17)2S5 is character-
ized by three peaks at 435, 459, and 493 cm–1, and a shoul-
der at 505 cm–1. The heptasulfane spectrum features four
The 2-naphthyl and 4-chlorophenyl groups have previ-
ously been used in the preparation of relatively stable sul-
fur-rich derivatives, from which it can be concluded that
these residues stabilize either sterically or electronically the
thermodynamically unstable sulfur compounds. Since the
corresponding sulfenyl chlorides are readily available,[21] we
have prepared bis(2-naphthyl)heptasulfane 4 and bis(4-
chlorophenyl)heptasulfane 5 by reaction with titanocene
pentasulfide (Equation 12).
2 RSCl ϩ [Cp2TiS5] Ǟ R2S7 ϩ [Cp2TiCl2]
(12)
These reactions were carried out at 20 °C in carbon disul-
lines at 429, 445, 470, and 495 cm–1, and a shoulder at 463 fide solution; 4 was obtained as a pale-yellow powder in
cm–1. The Raman spectrum of (nC8H17)2S9 features me- 51% yield, while 5 formed lemon-yellow microcrystals (44%
dium to strong lines at 423, 437, 463, and 494 cm–1, with yield). Despite the bulky substituents, these compounds are
shoulders at 452 and 472 cm–1. All these lines must stem characterized by relatively low melting points of 55 °C (4)
from SS stretching modes as the Raman spectrum of n-oct- and 40 °C (5). Reversed-phase HPLC analyses of the
anethiol does not feature any lines in this region (see Fig- rapidly quenched melts did not reveal the presence of any
ure 2). The number of lines in the region 400–510 cm–1 is decomposition products. However, when the heptasulfanes
smaller than the expected number of SS stretching modes were heated to twice the melting temperatures (110 °C and
of 1–3, indicating that there must be some coincidental de- 80 °C, respectively) for 5 min., the naphthyl derivative de-
generacies.
composed to give a mixture of polysulfanes R2Sn with up
In view of the low freezing points of these liquid polysul- to 11 sulfur atoms, while the chlorophenyl derivative pro-
fanes, no mesogenic properties were to be expected near duced a similar series of homologous sulfanes with 3–12
room temperature. All three compounds solidify as glasses sulfur atoms. As mentioned above, such homologous series
on rapid cooling to –70 °C.
can be analysed by the systematic increase of the retention
Figure 2. Raman spectra of n-octanethiol and of the bis(n-octyl)polysulfanes (nC8H17)2Sn (n ϭ 5, 7, 9) in the range 400–550 cm–1
Eur. J. Inorg. Chem. 2000, 921Ϫ928
923

R. Steudel, K. Hassenberg, V. Münchow, O. Schumann, J. Pickardt
FULL PAPER
time with increasing number nS of sulfur atoms. The reten- and elemental sulfur in the presence of DABCO at 160–185
tion index RS is a linear function of nS and the following °C (yield 54%).[25] The melting point of 6 measured by these
data were determined using methanol as an eluent:
authors was 58–60 °C, which agrees well with our findings.
Under similar conditions as those used to generate 6, 1,2-
benzenebis(sulfenyl chloride) was found to react with titan-
ocene pentasulfide to yield the novel 1,2,3,4,5,6,7-
benzoheptathionin 7, which was obtained in 83% yield as a
yellow solid with m.p. 107 °C (Equation 14).
RS ϭ a ϩ bnS
4: nS ϭ 2–11, a ϭ 517, b ϭ 69
5: nS ϭ 2–12, a ϭ 382, b ϭ 67
The linear correlation coefficients were better than 0.999.
Both heptasulfanes were found to be well-soluble in car-
bon disulfide and in chlorinated aliphatic hydrocarbons.
They may be stored for long periods at 4 °C without de-
composition, but slow decomposition occurs at 20 °C.
HPLC analysis, mass spectrometry, as well as infrared, Ra-
1,2-C6H4(SCl)2 ϩ [Cp2TiS5] Ǟ 1,2-C6H4S7 ϩ [Cp2TiCl2]
(14)
The new octasulfane 1,2,3,4,5,6,7,8-benzooctathiecin 8, a
yellow solid with m.p. 73 °C, was obtained in 60% yield
following reaction of the zinc hexasulfido chelate complex
1
man, H- and 13C-NMR spectroscopic data confirmed the
[26]
[(TMEDA)ZnS6]
with 1,2-benzenebis(sulfenyl chloride)
identities and purities of 4 and 5. Their low melting points
can be explained as follows. The torsion angle at SS bonds
is usually about 90°, but may be positive or negative (en-
antiomeric forms). A chain with six SS bonds can therefore
theoretically exist as 26 ϭ 64 conformational isomers. It has
previously been shown that many of these conformers will
be of almost identical energy.[22] However, in crystals of
polysulfanes usually only one conformer is found.[1] It
therefore seems reasonable to assume that only a single con-
formation of the CSSSSSSSC chain is present in solid 4 and
5, while several conformations will be present in their melts,
thus resulting in a strong increase in entropy. The melting
temperature Tm and the melting entropy ∆Sm are inversely
related to each other, with the melting enthalpy as an addi-
tional factor: Tm ϭ ∆Hm/∆Sm. Therefore, long chain-like
polysulfanes are either liquid at 20 °C or have melting
points only slightly above ambient temperature.
in carbon disulfide at ambient temperature (Equation 15;
TMEDA ϭ tetramethylethylenediamine).
The number of sulfur atoms in these cyclic polysulfides
can again be assessed by reversed-phase HPLC, since there
is a linear relationship between the number of sulfur atoms
in the ring and the logarithm of the capacity factor (not
shown). The 1H-NMR spectra of 6–8 each feature an
AAЈBBЈ system, which is centered at δ ϭ 7.61 for the C2S5
ring, at δ ϭ 7.63 for the C2S7 ring, and at δ ϭ 7.59 for the
C2S8 ring. The 13C-NMR spectra feature only three signals
in the expected region. The infrared spectra are all very sim-
ilar, in line with expectation. They are dominated by a very
strong absorption near 750 cm–1, which is typical for 1,2-
substituted benzene rings. More interesting are the Raman
spectra, which show the SS stretching modes between 400
and 520 cm–1 (see Figure 3). The three heterocycles each
exhibit a distinct pattern of SS stretching modes. In the rel-
evant region, the spectrum of the benzopentathiepin fea-
tures four lines at 418, 429, 467, and 490 cm–1, that of the
benzoheptathionine features five lines at 436, 451, 471, 495,
and 518 cm–1 and a shoulder at 480 cm–1, while that of the
benzooctathiocene is characterized by six lines at 416, 428,
438, 460, 467, and 512 cm–1 with shoulders at 476 and 515
cm–1.
Cyclic Polysulfanes
The titanocene complex [(CpЈ2TiCl)2S3] reacts with 1,2-
benzenebis(sulfenyl chloride), prepared by chlorination of
1,2-benzenedithiol, at low temperatures in carbon disulfide
solution to yield the known yellow 1,2,3,4,5-benzopenta-
thiepin 6 (Equation 13).
´
Compound 6 was first synthesized by Feher and
Langer[23] by condensation of 1,2-benzenedithiol
C6H4(SH)2 with dichlorotrisulfane S3Cl2. It was obtained
in a yield of just 50% and was seemingly not very pure since
the reported melting point of 65–66 °C differs substantially
from our measurements. Our product was analytically,
chromatographically, and spectroscopically pure and was
found to melt at 58 °C. It was recovered in 73% yield. In
The crystal structure of C6H4S7 was determined by
single-crystal X-ray diffraction analysis. The crystals were
found to be orthorhombic with four molecules in the unit
cell and a density of 1.765 g cm–3 at 20 °C. The molecules
have Cs symmetry (Figure 4). The crystallographic mirror
plane passes through the center of the C3–C3Ј bond and
contains S4.
´
1979, Feher and Engelen determined the molecular and
crystal structure of 6,[24] and in 1984 Chenard and Miller
reported a new synthesis of 6 from 1,2-benzothiadiazole
924
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Sulfur Compounds, 212
FULL PAPER
Figure 3. Raman spectra of the solid 1,2-benzenepolysulfanes C6H4Sn (n ϭ 5, 7, and 8) at 20 °C in the range 400–550 cm–1
slight alternation in the SS bond lengths in 7: d(S1ϪS2) ϭ
205.0(1), d(S2ϪS3) ϭ 203.7(1), and d(S3ϪS4) ϭ 205.7(1)
pm. The conformations of sulfur homocycles and sulfur-
rich heterocycles can best be characterized by the motif,
which describes the order of the signs of the torsion angles
around the ring. The motif for the C2S7 heterocycle is ϩ-
ϩ-0ϩ-ϩ-, with a value of zero at the carbon–carbon bond.
Such a motif has not previously been observed for any nine-
membered heterocycle of the type CxSy. The absolute values
of the torsion angles at the SS bonds lie between 85° and
110° (see Table 2).
 plot)
Figure 4. Structure of the 1,2-C6H4S7 molecule in the crystal (-
Table 2. Selected bond lengths [pm], valence angles [°], and torsion
angles [°] for C6H4S7 (symmetry transformations used to generate
equivalent atoms: Ј ϭ x, –y ϩ 1/2, z)
Conclusions
We have shown that sulfur-rich organic polysulfanes can
be prepared in good yield not only from titanocene polysul-
fido complexes, but also from the relatively new zinc hexa-
sulfido complex, despite the presence of the amine
TMEDA. Normally, amines catalyze the decomposition of
thermodynamically unstable polysulfur compounds. The
novel bis(n-octyl)polysulfanes described here, which consist
of chains of more than 20 non-hydrogen atoms, do not form
mesogenic phases at ambient temperature since their freez-
ing temperatures are quite low. These chains most probably
have a random coil conformation rather than a straight
chain structure in the liquid phase and therefore the mat-
Selected internuclear distances, bond angles, and torsion erials solidify as glasses. The chain-like polysulfanes bearing
angles are listed in Table 2.
aromatic substituents are solids at 20 °C, even when the
The geometrical parameters show the expected values sulfur chain is quite long. Most probably, they exist as a
with an arithmetic mean of 138.1 pm for the CC bonds and single conformer in the solid state, but as many rotational
an average of 204.8 pm for the SS bonds. The latter value isomers in the liquid state, leading to a high melting entropy
is identical to the average bond length in S8. There is a and hence to a depression of the melting temperature. Once
Eur. J. Inorg. Chem. 2000, 921Ϫ928
925

R. Steudel, K. Hassenberg, V. Münchow, O. Schumann, J. Pickardt
FULL PAPER
37.3, H 6.7, S 56.0; found C 37.7, H 6.4, S 56.3. – UV/Vis (meth-
anol): λmax (%) ϭ 228 nm (100), 284 (sh). – MS (160 °C): m/z (%) ϭ
450 (0.2) [Mϩ – 2S], 418 (2) [Mϩ – 3S], 386 (4) [Mϩ – 4S], 145
again, we have observed that the homologous members of
the series R2Sn with n ϭ 2–12 exhibit a systematic increase
in their reversed-phase HPLC retention times with increas-
ing number of sulfur atoms.
1
(100) [C8H17S]. – H NMR (200 MHz, CDCl3): δ ϭ 3.01 (t, 4 H),
1.79 (tt, 4 H), 1.47–1.29 (br. s, 20 H), 0.90 (t, 6 H). – 13C NMR
(50 MHz, CDCl3): δ ϭ 39.8, 31.8, 29.1, 28.9, 28.4, 22.6, 14.1. –
Raman (40 mW, –135 °C): ν˜ ϭ 423 cm–1 (SS), 437 (SS), 452 (SS),
463 (SS), 472 (SS), 494 (SS).
Experimental Section
General: The reactions were carried out under exclusion of mois-
Synthesis of Bis(2-naphthyl)heptasulfane (4): To a stirred solution
ture using carefully dried solvents. The chromatographic system
of C10H7SCl (0.29 g, 1.49 mmol) in CS2 (40 mL), [Cp2TiS5] (0.25 g,
used has been described previously.[11] Octadecylsilane (C18) was 0.74 mmol) was added at 20 °C under an N2 atmosphere. After the
used as a stationary phase throughout. The following spectrometers
were used: Nicolet Magna 750 FT-IR spectrometer (using KBr or
CsCl sample discs); Bruker RFS 100 FT Raman spectrometer,
equipped with an Nd-YAG laser (1064 nm); Bruker ARX 200 and
ARX 400 NMR spectrometers.
color had changed to orange-red, the precipitated [Cp2TiCl2] was
filtered off and the filtrate was stirred with a few mg of silica gel
to bind residual titanocene dichloride. After filtration, the solvent
was evaporated to leave a yellow oil, which was dissolved in a small
volume of CH2Cl2. A little n-hexane was added and the mixture
was concentrated until some turbidity appeared. It was then cooled
to –50 °C, which led to the deposition of crystals of 4. The collected
crystals were washed with n-hexane and dried to give 4 as a yellow
powder, m.p. 55–58 °C; yield 0.18 g (51%). – C20H14S7 (478.8):
calcd. C 50.2, H 3.0, S 46.9; found C 50.1, H 3.1, S 45.3. – UV/Vis
(methanol): λmax (%) ϭ 222 nm (92), 233 (97), 236 (100), 240 (98),
281 (34), 334 (14). – MS (210 °C): m/z (%) ϭ 446 (0.3) [Mϩ – S],
115 (100) [C9H7]. – 1H NMR (200 MHz, CD2Cl2): δ ϭ 8.09 (d),
7.83 (m), 7.68 (dd), 7.53 (m). – 13C NMR (50 MHz, CD2Cl2): δ ϭ
127.0, 127.5, 127.8, 127.8, 129.3, 129.9, 133.0, 133.1, 133.4. – Ra-
man (40 mW; 20 °C): ν˜ ϭ 394 cm–1 (m), 417 (sh), 430 (vs), 441 (s),
473 (vs), 505 (sh), 511 (s), 521 (m).
Synthesis of Bis(n-octyl)pentasulfane (1): n-Octylsulfenyl chloride
was first prepared by chlorination of the corresponding thiol with
one equivalent of sulfuryl chloride in dichloromethane at 0 °C ac-
cording to standard procedures. At –70 °C, a solution of the sul-
fenyl chloride (0.181 g, 1 mmol) in CS2 (25 mL) was added drop-
wise over a period of 1 h to a solution of [(CpЈ2TiCl)2S3] (0.290 g,
0.5 mmol) in CS2 (25 mL), which resulted in a color change from
dark-green to light-red. The reaction mixture was allowed to warm
to 20 °C, the volume was reduced to one-half of the original, and
then the concentrated solution was cooled to –50 °C for several
hours. The precipitated [CpЈ2TiCl2] was filtered off. This procedure
(partial evaporation of the solvent and subsequent cooling) was
repeated until no more titanocene dichloride was precipitated. The
remaining solvent was then completely removed under reduced
Synthesis of Bis(4-chlorophenyl)heptasulfane (5): To a stirred solu-
tion of [Cp2TiS5] (1.00 g, 2.96 mmol) in CS2 (70 mL), ClC6H4SCl
pressure yielding the liquid product. Yield: 0.193 g (quantitative); (1.06 g, 5.91 mmol) was added at 20 °C. After 5 min., the color had
freezing temp. –66 to –68 °C. – C16H34S5 (386.8): calcd. C 49.7, H
8.9, S 41.5; found C 50.8, H 8.2, S 40.4. – UV/Vis (methanol): λmax
changed to orange and the precipitated [Cp2TiCl2] was filtered off.
A few mg of silica gel was added to the filtrate to bind residual
(%) ϭ 216 nm (100), 292 (sh). – MS (120 °C): m/z (%) ϭ 386 (23) titanocene dichloride. After stirring for a few min., the solution
1
[Mϩ], 322 (100). – H NMR (200 MHz, CDCl3): δ ϭ 2.99 (t, 4 H), was filtered, the filtrate was concentrated to a volume of 5 mL, and
1.78 (tt, 4 H), 1.45–1.29 (br. s, 20 H), 0.89 (t, 6 H). – 13C{1H}
then n-pentane (10 mL), MTB ether (15 mL), and ethanol (15 mL)
NMR (50 MHz, CDCl3): δ ϭ 39.9, 31.8, 29.1, 29.1, 28.8, 28.4, 22.6, were added. The solvents were then evaporated until the solution
14.1. – Raman (80 mW, 20 °C): ν˜ ϭ 505 cm–1 (SS), 493 (SS), 459 became turbid. Cooling of the solution to –78 °C led to the depos-
(SS), 435 (SS).
ition of crystals of 5 (m.p. 40 °C), which were filtered off, washed
with n-pentane, and dried in air; yield 0.58 g (44%). – C12H8Cl2S7
(447.6): calcd. C 32.2, H 1.8, S 50.2; found C 32.3, H 1.7, S 50.2. –
UV/Vis (methanol): λmax (%) ϭ 211 nm (93), 240 (100), 292 (30),
327 (23). – MS (160 °C): m/z (%) ϭ 418 (0.2), 414 (0.4) [Mϩ – S],
382 (2) [Mϩ – 2S], 175 (100) [C6H4ClS2]. – 1H NMR (200 MHz,
CD2Cl2): δ ϭ 7.57 (dm, 4 H), 7.36 (dm, 4 H). – 13C NMR
(50 MHz, CD2Cl2): δ ϭ 129.5, 132.0, 134.4, 135.0. – Raman
(40 mW; 20 °C): ν˜ ϭ 376 cm–1 (m), 419 (w), 435 (vs), 456 (vw), 473
(vs), 509 (m), 541 (m).
Synthesis of Bis(n-octyl)heptasulfane (2) and -nonasulfane (3): To a
stirred solution of [Cp2TiS5] (0.846 g, 2.5 mmol) in CS2 (30 mL)
at –20 °C (2) or at –70 °C (3), a solution of n-octylsulfenyl chloride
(0.904 g, 5 mmol) or n-octylchlorodisulfane (1.064 g, 5 mmol) in
CS2 (40 mL) was added dropwise. [The chlorodisulfane, a yellow
viscous liquid, had been prepared from the thiol (10 mmol) and
SCl2 (12 mmol) in CH3OtBu at –70 to ϩ20 °C]. The color turned
from dark-red to light-red. The precipitated [Cp2TiCl2] was re-
moved by filtration at 20 °C in the case of 2 and at –20 °C in the
case of 3 and the filtrate was concentrated to one-half of its original Synthesis of 1,2,3,4,5-Benzopentathiepin (6): To a stirred solution
volume. After cooling to –50 °C for several hours, the precipitated
[Cp2TiCl2] was filtered off. On complete removal of the solvent
under reduced pressure, the liquid polysulfane was obtained. Yield:
1.127 g of the heptasulfane or 1.290 g of the nonasulfane (both
quantitative). – 2: freezing temp. –61 °C. – C16H34S7 (450.9): calcd.
C 42.6, H 7.6, S 49.8; found C 43.3, H 7.8, S 48.0. – UV/Vis (meth-
of [(CpЈ2TiCl)2S3] (0.150 g, 0.259 mmol) in CS2 (40 mL) at –78 °C,
solution of 1,2-benzenebis(sulfenyl chloride) (0.055 g,
0.259 mmol) in CS2 (40 mL) was added dropwise over a period of
20 min. [The bis(sulfenyl chloride) had been prepared by chlorina-
tion of the corresponding dithiol using elemental chlorine in CCl4
at 0 °C]. On warming the reaction mixture to ambient temperature,
a
anol): λmax (%) ϭ 226 nm (100), 300 (sh). – MS (160 °C): m/z (%) ϭ the color changed from dark-green to light-red. After filtering off
450 (1) [Mϩ], 418 (7) [Mϩ – S], 386 (10) [Mϩ – 2S], 322 (100) [Mϩ
–
the precipitated [CpЈ2TiCl2], the filtrate was concentrated to one-
1
4S]. – H NMR (200 MHz, CDCl3): δ ϭ 3.00 (t, 4 H), 179 (tt, 4 quarter of its original volume and the mixture was cooled to –
H), 1.46–1.29 (br. s, 20 H), 0.90 (t, 6 H). – 13C NMR (50 MHz,
55 °C for several hours. After another filtration, the solvent was
CDCl3): δ ϭ 39.8, 31.8, 29.1, 29.1, 28.9, 28.4, 22.6, 14.1. – Raman completely removed under reduced pressure. The yellow crude
(40 mW, –135 °C): ν˜ ϭ 429 cm–1 (SS), 445 (SS), 463 (SS), 470 (SS),
495 (SS). – 3: freezing temp. –53 °C. – C16H34S9 (515.1): calcd. C
product was recrystallized from a mixture of CS2 and CH3OtBu
(1:1). Yield: 0.045 g (73%); m.p. 58 °C. – C6H4S5 (236.4): calcd. C
926
Eur. J. Inorg. Chem. 2000, 921Ϫ928

Sulfur Compounds, 212
FULL PAPER
30.4, H 1.7, S 67.7; found C 30.3, H 1.4, S 66.1. – UV/Vis (meth-
cell dimensions by refinement of the reflections obtained from all
anol): λmax (%) ϭ 223 nm (100), 272 (sh), 314 (sh). – MS (88 °C): frames. The compound crystallizes in the space group Pnma (no.
m/z (%) ϭ 236 (16) [Mϩ], 172 (100) [Mϩ – S2]. – 1H NMR
(200 MHz, CD2Cl2): δ ϭ 7.85 (m, 2 H), 7.36 (m, 2 H). – 13C NMR
62). An empirical absorption correction (SADABS[27]) was per-
formed. Structure solution and refinement were performed using
(50 MHz, CDCl3): δ ϭ 143.8, 135.8, 129.6. – Raman (150 mW, 20 SHELXTL.[28] H atom positions were calculated assuming tri-
°C): ν˜ ϭ 418 cm–1 (SS), 428 (SS), 467 (SS), 490 (SS).
gonal-planar coordination of C atoms with C–H distances of 93
pm and were refined as riding on the C atoms with isotropic tem-
perature factors 1.2Uequiv. of the corresponding C atoms. A sum-
mary of data collection and refinement is given in Table 3. Crystal-
lographic data (excluding structure factors) have been deposited
with the Cambridge Crystallographic Data Centre as supplement-
ary publication no. CCDC-136074. Copies of the data can be ob-
tained free of charge on application to the CCDC, 12 Union Road,
Cambridge CB2 1EZ, U.K. [Fax.: (internat.) ϩ44 (0)1223 336033;
E-mail: deposit@ccdc.cam.ac.uk].
Synthesis of 1,2,3,4,5,6,7-Benzoheptathionin (7): The synthesis was
carried out in analogy to the preparation of 4 starting from
[Cp2TiS5] (0.8 g, 2.37 mmol) in CS2 (150 mL) and 1,2-benzene-
bis(sulfenyl chloride) (0.5 g, 2.37 mmol) in CS2 (50 mL). Yield:
0.59 g (83%); m.p. 107 °C. – C6H4S7 (300.6): calcd. C 24.0, H 1.3;
found C 24.2, H 1.1. – UV/Vis (methanol): λmax (%) ϭ 218 nm
(100), 295 (sh). – MS (149 °C): m/z (%) ϭ 300 (2) [Mϩ], 172 (100)
1
[C6H4S3]. – H NMR (200 MHz, CD2Cl2): δ ϭ 7.77 (m, 2 H), 7.48
(m, 2 H). – 13C NMR (50 MHz, CDCl3): δ ϭ 137.9, 135.2, 131.3. –
Raman (150 mW, 20 °C): ν˜ ϭ 436 cm–1 (SS), 451 (SS), 471 (SS),
495 (SS), 518 (SS).
Acknowledgments
Synthesis of 1,2,3,4,5,6,7,8-Benzooctathiecin (8): To a stirred solu-
tion of [(TMEDA)ZnS6] (0.326 g, 0.94 mmol) in CS2 (30 mL), a
solution of 1,2-benzenebis(sulfenyl chloride) (0.2 g, 0.94 mmol) in
CS2 (20 mL) was added dropwise over a period of 30 min. After
stirring for 1 h, the precipitated [(TMEDA)ZnCl2] was filtered off
and the solvent was removed completely from the filtrate. The
crude yellow oil was crystallized from a mixture of CS2 and MTB
ether (1:1). Yield: 0.19 g (60%); m.p. 73 °C. – C6H4S8 (332.6): calcd.
C 21.7, H 1.2; found C 21.2, H 0.9. – UV/Vis (methanol): λmax
(%) ϭ 213 nm (100), 235 (sh), 318 (sh). – MS (120 °C): m/z (%) ϭ
332 (1) [Mϩ], 172 (100) [C6H4S3]. – 1H NMR (200 MHz, CD2Cl2):
δ ϭ 7.74 (m, 2 H), 7.43 (m, 2 H). – 13C NMR (50 MHz, CDCl3):
δ ϭ 139.4, 133.9, 129.8. – Raman (150 mW, 20°C): ν˜ ϭ 416 cm–1
(SS), 428 (SS), 438 (SS), 460 (SS), 467 (SS), 512 (SS).
This work was supported by the Deutsche Forschungsgemeinschaft
and the Verband der Chemischen Industrie.
[1]
Review: R. Steudel, M. Kustos, Encyclopedia of Inorganic
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4009–4038.
[2]
R. Steudel, Top. Curr. Chem. 1982, 102, 149–176.
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R. Steudel, in The Chemistry of Inorganic Ring Systems (Ed.:
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R. Steudel, M. Kustos, M. Pridöhl, U. Westphal, Phosphorus,
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1996, 622, 1594–1600.
[5]
[6]
Table 3. Crystal data and structure refinement for C6H4S7
[7]
Empirical formula
Formula weight
Temperature [K]
C6H4S7
[8]
300.51
293(2)
0.71073
[9]
˚
Wavelength [A]
Crystal system
Space group
Z
orthorhombic
Pnma
[10]
4
˚
a [A]
17.7990(7)
13.2422(6)
4.7990(2)
1131.11(8)
1.765
[11]
˚
b [A]
˚
c [A]
[12]
3
R. Steudel, M. Kustos, A. Prenzel, Z. Naturforsch. Part B 1997,
52, 79–82.
M. Kustos, R. Steudel, J. Org. Chem. 1995, 60, 8056–8061.
A. K. Verma, T. B. Rauchfuss, Inorg. Chem. 1995, 34, 6199.
˚
V [A ]
D (calcd.) [g cm–3]
[13]
µ [mm–1]
1.342
[14]
Crystal size [mm]
2θ range [°]
0.3 ϫ 0.08 ϫ 0.08
4.58–55.00
h ±22, k ϩ17, l ±6
7947
[15]
R. Steudel, O. Schumann, J. Buschmann, P. Luger, Angew.
Index ranges
Chem. 1998, 110, 2502–2504; Angew. Chem. Int. Ed. 1998, 37,
Collected reflections
Independent reflections
Obsd. with I Ͼ 2σ(I)
Data/restraints/parameters
Goodness-of-fit on F2
R1 [I Ͼ 2σ(I)]
2377–2378.
1358 (Rint ϭ 0.0625)
916
[16]
For more details, see O. Schumann, Doctoral Dissertation,
Techn. Univ. Berlin, 1999.
R. Steudel, S. Förster, J. Albertsen, Chem. Ber. 1991, 124,
2357–2359.
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1990, 45, 1282–1290.
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For more details, see V. Münchow, Doctoral Dissertation,
Techn. Univ. Berlin, 1996.
T. Zincke, K. Eismayer, Ber. Dtsch. Chem. Ges. 1918, 51, 751.
E. Gebauer-Fülnegg, J. Am. Chem. Soc. 1927, 49, 2270.
Y. Drozdova, K. Miaskiewicz, R. Steudel, Z. Naturforsch. Part
B 1995, 50, 889–893.
1358/0/61
1.119
[17]
0.0507
[18]
R1 (all data)
Largest diff. peak/hole [eA ]
0.0889
–3
˚
0.425/–0.229
[19]
[20]
Crystallography: Crystals were obtained by dissolving 7 in carbon
disulfide and adding n-hexane until the mixture became turbid. On
cooling this mixture to 4 °C, crystals separated. Diffraction meas-
urements were made at room temperature using a Siemens SMART
CCD diffractometer (Mo-Kα radiation, 10 s per frame, 0.3° ω-scan
increments, specimen–detector distance 3 cm). Preliminary lattice
constants were obtained from 45 orientation frames and final unit
[21]
[22]
[23]
´
F. Feher, M. Langer, Tetrahedron Lett. 1971, 24, 2125.
[24]
[25]
´
F. Feher, B. Engelen, Z. Anorg. Allg. Chem. 1979, 452, 37.
B. L. Chenard, T. J. Miller, J. Org. Chem. 1984, 49, 1221.
Eur. J. Inorg. Chem. 2000, 921Ϫ928
927

R. Steudel, K. Hassenberg, V. Münchow, O. Schumann, J. Pickardt
FULL PAPER
[26]
[28]
A. K. Verma, T. B. Rauchfuss, S. R. Wilson, Inorg. Chem. 1995,
G. M. Sheldrick, SHELXTL Software Reference Manual, ver-
34, 3072.
sion 5.1, Bruker AXS Inc., Madison, Wisconsin, USA, 1997.
[27]
G. M. Sheldrick, SADABS, University of Göttingen, Ger-
many, 1996.
Received October 19, 1999
[I99372]
928
Eur. J. Inorg. Chem. 2000, 921Ϫ928