Reactions of hydrogen sulfide with singly and doubly tucked-in titanocenes

Article abstract of DOI:10.1021/om1010726

Hydrogen sulfide reacts with tucked-in titanocene complexes [Ti(III){η⁵:η¹-C₅Me₄(CH ₂)}Cp*] (Cp* = η⁵-C₅Me ₅) (2) and [Ti{η⁴:η³-C ₅Me₃(CH₂)₂}Cp*] (3) and their precursors [Cp*₂TiMe] (2a) and [Cp*₂Ti(η²-Me₃SiC≡CSiMe₃)] (3a), respectively, to give the corresponding titanocene hydrosulfides [Cp*₂Ti(SH)] (4) and [Cp*₂Ti(SH)₂] (1), respectively. Hydrogen sulfide also cleaves intramolecular σ- or π-Ti-C bonds in ansa-[Ti^III(η¹:η⁵: η⁵-C₅Me₄SiMe₂CHCH ₂SiMe₂C₅Me₄)] (5) and ansa-[Ti ^II(η²:η⁵:η⁵-C ₅Me₄SiMe₂CH=CHSiMe₂C ₅Me₄)] (6), affording hydrosulfides ansa- [(η⁵-CH₂Me₂SiC₅Me ₄)₂Ti(SH)] (7) and ansa-[(η⁵-CH ₂Me₂SiC₅Me₄)₂Ti(SH) ₂] (8). The S-H bonds of hydrosulfides 4 and 7 were able to react with the Ti-C bonds in 2 and 5, affording titanocene sulfides [(Cp*₂Ti^III)₂S] (11) and ansa-[{(η⁵-CH₂Me₂SiC₅Me ₄)₂Ti^III}₂S] (12), respectively. Combination of 7 with 2a gave rise to the mixed titanocene sulfide [ansa-{(η⁵-CH₂SiMe₂C₅Me ₄)₂Ti}S(TiCp*₂)] (13). The titanium(III) d¹ electrons in 11-13 form an electronic triplet state well observable by EPR spectra in toluene glass. All the hydrosulfides were decomposed by sunlight. Compound 1 eliminated Cp*H and H₂S, while 4 mainly Cp*H. Apparently formed transient [Cp*TiS] species probably gave rise to the serendipitously isolated cluster [{Cp*Ti(S)} ₄] (14). Crystal structures of the all complexes were determined by X-ray diffraction analysis.

Full text of DOI:10.1021/om1010726

1034 Organometallics 2011, 30, 1034–1045
DOI: 10.1021/om1010726
Reactions of Hydrogen Sulfide with Singly and Doubly
Tucked-in Titanocenes
†
Jirı Pinkas, Ivana Cısarova, Michal Horacek, Jirı Kubista, and Karel Mach*
†
†
,†
ꢀꢁ
ꢁ ꢀ ꢁ ‡
ꢁꢀ
ꢀꢁ
ꢀ
†
ꢁ
J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, v.v.i.,
ꢀ
‡
Dolejskova 3, 182 23 Prague 8, Czech Republic, and Department of Inorganic Chemistry,
Charles University, Hlavova 2030, 128 40 Prague 2, Czech Republic
Received November 15, 2010
Hydrogen sulfide reacts with tucked-in titanocene complexes [Ti(III){η5:η1-C5Me4(CH2)}Cp*]
(Cp* = η5-C5Me5) (2) and [Ti{η4:η3-C5Me3(CH2)2}Cp*] (3) and their precursors [Cp*2TiMe] (2a)
and [Cp*2Ti(η2-Me3SiCtCSiMe3)] (3a), respectively, to give the corresponding titanocene hydro-
sulfides [Cp*2Ti(SH)] (4) and [Cp*2Ti(SH)2] (1), respectively. Hydrogen sulfide also cleaves
intramolecular σ- or π-Ti-C bonds in ansa-[TiIII(η1:η5:η5-C5Me4SiMe2CHCH2SiMe2C5Me4)] (5)
and ansa-[TiII(η2:η5:η5-C5Me4SiMe2CHdCHSiMe2C5Me4)] (6), affording hydrosulfides ansa-[(η5-
CH2Me2SiC5Me4)2Ti(SH)] (7) and ansa-[(η5-CH2Me2SiC5Me4)2Ti(SH)2] (8). The S-H bonds of
hydrosulfides 4 and 7 were able to react with the Ti-C bonds in 2 and 5, affording titanocene sulfides
[(Cp*2TiIII)2S] (11) and ansa-[{(η5-CH2Me2SiC5Me4)2TiIII}2S] (12), respectively. Combination of 7
with 2a gave rise to the mixed titanocene sulfide [ansa-{(η5-CH2SiMe2C5Me4)2Ti}S(TiCp*2)] (13).
The titanium(III) d1 electrons in 11-13 form an electronic triplet state well observable by EPR
spectra in toluene glass. All the hydrosulfides were decomposed by sunlight. Compound 1 eliminated
Cp*H and H2S, while 4 mainly Cp*H. Apparently formed transient [Cp*TiS] species probably gave
rise to the serendipitously isolated cluster [{Cp*Ti(S)}4] (14). Crystal structures of the all complexes
were determined by X-ray diffraction analysis.
Introduction
gained importance as catalysts for sulfur removal from
petroleum via hydrodesulfurization.2d-g These applications
stimulate the unceasing interest in investigation of the whole
range of mononuclear as well as homo- and heteropoly-
nuclear transition metal complexes containing sulfur ligands
as bridging moieties.3 Titanocene-sulfide chemistry, in spite
of undoubted progress since the 1960s, remained relatively
less developed,3g needing some basic knowledge on simple
highly substituted titanocene (TiIV and TiIII)-hydrosulfide
and sulfide complexes.
Hydrogen sulfide is one of the most toxic gases;1a however,
it is also considered to be, in addition to NO and CO, a
gaseous hormone endogenously produced, e.g., by enzy-
matic decomposition of cysteine and homocysteine.1b This
important signaling biological compound has been shown to
play important roles, e.g., in central nervous and cardiovas-
cular systems,1c-e and its physiological as well as pathophys-
iological effects are intensely studied. A long known,
however, still intensely studied are sulfide complexes of
biogenic transition metals (Fe, Co, Ni) that constitute a
family of life-important enzymes,2a-c whereas the sulfides
of some other transition metals (Mo, W, Ru, Os, Rh, Ir, Re)
Titanocene-sulfur chemistry was opened by the discovery
of titanacyclohexasulfane complex [Cp2TiS5] (Chart 1, I)
by E. Samuel in 19664a and independently by H. Kopf
€
et al.4b The X-ray crystal structures of both of its two
crystallographic modifications revealed the chair structure
of its six-membered ring,5 which appeared to be suitable
for insertion6a and substitution reactions with organic
reagents.6b Simple titanocene dihydrosulfide [Cp2Ti(SH)2]
*To whom correspondence should be addressed. E-mail: karel.mach@
jh-inst.cas.cz.
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52086. (c) Moore, P. K.; Bhatia, M.; Moochhala, S. Trends Pharmacol. Sci.
2003, 24, 609–611. (d) Chen, C.-Q.; Xin, H.; Zhu, Y.-Z. Acta Pharmacol.
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r
pubs.acs.org/Organometallics
Published on Web 01/21/2011
2011 American Chemical Society

Article
Organometallics, Vol. 30, No. 5, 2011 1035
Chart 1
was prepared from [Cp2TiCl2] and H2S in the presence of
NEt3.7a Attempts to use it for preparation of titanacyclo-
sulfanes with different sulfur content largely yielded
[Cp2TiS5];7a however, a better crystallizing [(C5H4Me)2Ti-
(SH)2] has been suggested to dehydrogenate to give
[(C5H4Me)2Ti(μ-S2)]2, forming 1,4-dititanacyclohexasulfane
(Chart 1, II). This compound was actually obtained by
partial desulfurization of [(C5H4Me)2TiS5] with PBu3.7b
Similarly, the 1,5-dititanacyclooctasulfane complex (Chart 1,
III) was obtained from I using PPh3 as a desulfurization
agent.7c Both mentioned titanocene dihydrosulfides were
shown to have low-reactive S-H bonds; however, their
sulfur atoms were able to coordinate M(CO)4 (M=Mo, W)
moieties, giving rise to [Cp2Ti(μ-SH)2M(CO)4] complexes.7d
Deprotonation of [Cp2Ti(SH)2] appeared to be feasible with
NaH7e or LiBu,7f affording the ionic complex [Na2{CpTiS-
complex containing a titanacyclobutasulfane ring (Chart 1,
IV).8 A convenient entry to the permethyltitanocene dihy-
drosulfide, [Cp*2Ti(SH)2] (1), was discovered by F. Bottom-
ley et al.,9a who explored the titanium(II) complex [Cp*2-
Ti(CO)2] in a redox reaction with H2S under condition that
the latter was not in excess during the reaction. The overall
stoichiometry of the reaction is given in eq 1.
ꢀ
ꢀ
Cp 2TiðCOÞ2 þ 2H2S f Cp 2TiðSHÞ2 þ H2 þ 2CO
ð1Þ
Analogous treatment of [Cp2Ti(CO)2] with H2S yielded
mainly the cluster [(CpTi)5S6] (Chart 1, V),9b similar to an
extremely stable oxygen complex [(CpTi)6O8] prepared analo-
gously from [Cp2Ti(CO)2] and water.9c The analogous zirco-
nium dicarbonyls [Cp2Zr(CO)2] and [Cp*2Zr(CO)2] afforded
dehydrogenated dimeric sulfides, with the crystal structure
determined for [Cp2Zr(μ-S)]2 only.9a The tucked-in zirconocene
complex [ZrI{η5:η1-C5Me4(CH2)}Cp*] was reacted with H2Sto
give [Cp*2Zr(SH)I], which afforded the highly reactive
[Cp*2ZrdS] species.9d An elegant method exploring thermally
stable Ti(II) titanocene complexes was also applied by R. A.
Andersen et al. for synthesis of the sulfide [Cp*2Ti(dS)-
(pyridine)] and the disulfide [Cp*2Ti(S2)] (Chart 1, VI) com-
plexes from [Cp*2Ti(η2-C2H4)] and stoichiometric amounts of
sulfur. Molecular hydrogen was shown to convert the sulfide
complex to [Cp*2TiH(SH)] and the disulfide VI to 1, proving
thus the hydrogenation step in the desulfurization reaction.10
Here, we report reactions of hydrogen sulfide with tucked-
in titanocene complexes [Ti(III){η5:η1-C5Me4(CH2)}(Cp*)]
(2)11a and [Ti{η4:η3-C5Me3(CH2)2}(Cp*)] (3)12a and their
(μ-S)}2 4THF]2. This was proved to be an intermediate in
3
the formation of intermetallic clusters [CpTi(μ3-S)3M3-
(diolefin)3] (M = Rh, Ir) from [{M(μ-Cl)(diolefin)}2] and
[Cp2Ti(SH)2] in the presence of LiBu.7f The deprotonation of
[Cp2Ti(SH)2] with leaving anionic ligand (A) from [M(A)-
(diolefin)2] (M=Rh, Ir, A=acac, quinol) afforded trinuclear
complexes [Cp(A)Ti(μ3-S)2{M(diolefin)2}2].7g Deprotona-
tion of the adduct of [Cp2Ti(SH)2] with [Cp*RuCl] afforded
a pseudocubane cluster composed of two [CpTiS] and two
[Cp*RuS] moieties.7h
The sterically more congested [Cp*2TiCl2] was shown to
be inert toward H2S in the presence of NEt3; however, when
reacted with Li2S5 it afforded the first permethyltitanocene-sulfur
(5) (a) Epstein, E. F.; Bernal, I. J. Chem. Soc., Chem. Commun. 1970,
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1036 Organometallics, Vol. 30, No. 5, 2011
Pinkas et al.
precursors [Cp*2TiMe] (2a)11b and [Cp*2Ti(η2-Me3SiCt
CSiMe3)] (3a),12b respectively, yielding the corresponding
titanocene hydrosulfide [Cp*2TiSH] (4) and dihydrosulfide
1, respectively. Hydrogen sulfide was also reacted with
intramolecular σ- or π-Ti-C bonds in recently described
complexes ansa-[TiIII(η1:η5:η5-C5Me4SiMe2CHCH2SiMe2C5-
Me4)] (5) and ansa-[TiII(η2:η5:η5-C5Me4SiMe2CHdCHSiMe2-
C5Me4)] (6)13 in order to demonstrate the general applic-
ability of this access to titanocene hydrosulfides. The S-H
bonds of the obtained titanocene hydrosulfides 4 and 7 were
able to react with the Ti-C bonds in 2 and 5, affording
titanocene sulfides TiIII-S-TiIII. A serendipitious isolation
of the cluster [{Cp*Ti(μ3-S)}4] (14) justified preliminary
investigations of thermolysis and photolysis of 1 and 4.
the sense of “optimum atom economy”, as no other products
are formed in stoichiometric reactions, whereas methane and
hydrogenated bis(trimethylsilyl)ethyne derivatives are formed
from 2a and 3a, respectively. All the reactions proceed at
ambient temperature, compound 2 reacting somewhat faster
than compound 3, and both their precursors 2a and 3a faster
than the tucked-in compounds 2 and 3, in accord with their
energy content.14 The protolytic reactions of H2S also run
smoothly with the intramolecular Ti-C bond of the para-
magnetic ansa-titanocene compound ansa-[Ti(III){η1:η5:η5-
C5Me4SiMe2CHCH2SiMe2C5Me4}] (5) having the ansa-
chain tethered to titanium (eq 2) and with the back-bonding
Ti-C bonds of the π-coordinated double bond of the ansa-
chain in [Ti(II){η2:η5:η5-C5Me4SiMe2CHdCHSiMe2C5Me4}]
(6) (eq 3).
Results and Discussion
Protolytic reactions of H2S with the singly tucked-in
titanocene [Ti(III){η5:η1-C5Me4(CH2)}(Cp*)] (2)11a and its
precursor [Cp*2TiMe] (2a)11b are shown in Scheme 1, and
those with the doubly tucked-in [Ti{η4:η3-C5Me3(CH2)2}-
(Cp*)] (3)12a and its precursor [Cp*2Ti(η2-Me3SiCtCSiMe3)]
(3a)12b are shown in Scheme 2.
The reactions are visually observable since purple 2 or
green 2a affords the violet [Cp*2TiSH] (4), and blue 3 or
yellow 3a give rise to the known9a red [Cp*2Ti(SH)2] (1). The
use of the tucked-in compounds 2 and 3 is advantageous in
Scheme 1
These reactions were also accompanied by color changes as
brown 5 afforded violet ansa-[(η5-CH2Me2SiC5Me4)2Ti(SH)]
Scheme 2
Scheme 3

Article
Organometallics, Vol. 30, No. 5, 2011 1037
(7) and yellow 6 gave blood-red ansa-[(η5-CH2Me2SiC5-
Me4)2Ti(SH)2] (8). Due to uncertainty in dosing exact
amounts of gaseous H2S, a 1.1-1.5-fold molar excess of
H2S over the stoichiometry was used in order to avoid the
case of its insufficiency. Warming to 40 °C for up to 10 min
was used to accomplish the reaction, which was then
terminated by evaporation of all volatiles under vacuum.
No byproducts that could arise, e.g., from protolysis of
cyclopentadienyl ligands or other reactions of excessive
H2S, were detected throughout this work. The only experi-
ment without the presence of excess H2S was the reaction of
6 with approximately one molar equivalent of H2S, which
could yield, for example, products 9 and 10, depicted in
Scheme 3.
compounds 1 and 8 showed very low-abundant molecular
ions and their [M - 2 H]þ fragments and abundant [M -
HS]þ and M - H2S]þ ions. Compound 1 showed also
abundant [M - Cp*]þ and [M - Cp* - H2S]þ ions and
[HCp*]þ base peak. Compound 8 further displayed the [M
- 2 SH - 5 H]þ ion and [HSiMe2]þ as a base peak. The EI-
MS spectra of composed crystal [8/6] displayed mostly the
fragmentation of 8, whereas the base peak of 6 (M.þ, m/z
430)13 was negligible.
The ν(S-H) vibration of very low intensity was well
discernible in a narrow range, 2590-2607 cm-1, the mono-
hydrosulfides absorbing at higher wavenumbers than the
dihydrosulfides. For comparison, ν(S-H) for CH3SH ab-
sorbs at 2550 cm
,
-1 17a and H2S in Xe matrix at 17 K in the
Surprisingly, the main ocher-red crystalline product de-
noted [8/6] contained 8 and 6, one molecule each in its unit
cell, showing that the formation of 8 is preferred to other
possible products 9 and/or 10.
range 2580-2630 cm-1 17b
.
The discrepancy between the
reported9a value of 2580 cm-1 and the present 2600 cm-1
for 1 can be due to different medium (Nujol mull/KBr
pellet) or different crystal modification (see below). The
reported δH 2.73 ppm for S-H of 1 agrees with the present
Structures of all the compounds were identified by X-ray
single-crystal diffraction analysis (see below), and their
properties determined by current spectroscopic and ana-
lytical methods. Paramagnetic d1 titanocene hydrosulfides
4 and 7 extend the class of [Cp*2TiL] compounds, binding
an electronegative element in ligand L (L=halide, amide,
and alkoxide). Accordingly, they show very similar EPR g-
tensors and two electronic transitions in the visible spectral
region assigned to 1a1 f 2a1 and 1a1 f b1 transitions.15a
The electronic absorption band in the attainable near-
infrared region (800-2000 nm) due to 1a1 f b2 transition,
which indicates the extent of π-donation from electroneg-
ative element (N, O or F) to Ti(III),15 was not observed for
Ti-S bonds in 4 and 7. This does not imply the absence of
the π-donation at all since the corresponding transition
could occur at wavelength above 2000 nm, where its
observation could be difficult because of a large line-width
of the electronic transition compared to by orders more
intensive C-H valence vibration absorption bands. The
red color of 1 and 8 comes from the absorption band at 490
nm, which is a Cp* f Ti or S f Ti LMCT transition.16a It
is of interest that an analogous absorption band for
[Cp*2TiCl2] is observed at a much higher wavelength of
560 nm.16b
δ
H 2.85 ppm provided the solvent effect (CDCl3/C6D6) is
considered.
Formation of Titanocene Sulfides. The titanocene hydro-
sulfide 4 and ansa-titanocene hydrosulfide 7 maintain
the protolytic capability of their S-H moiety, as
demonstrated by reactions of 4 with 2 (eq 4) and 7 with 5
(eq 5).
Both 4 and 7 displayed their EI-MS spectra with high-
abundant molecular ions; however, their fragmentation
depended on the titanocene moiety. Compound 4 gave
fragments [M - HS]þ and [M - H2S]þ as virtually equal
intensity base peaks, while the [M - Cp*]þ fragment was
much less abundant. Compound 7 showed the abundant
fragment [M - H2S - 2H2]þ and [HSiMe2]þ as a base
peak. The extensive loss of hydrogen that is typical for
fragmentation patterns of ansa-[(η5-CH2Me2SiC5Me4)2-
Ti] derivatives13 accompanies the H2S elimination to
give the former ion. On the other hand, diamagnetic
Both reactions afforded green paramagnetic sulfides
[(Cp*2Ti)2S] (11) and ansa-[{(η5-CH2SiMe2C5Me4)2Ti}2S]
(12) in virtually quantitative yields. Heating to 60 °C for
30 min was necessary to complete the reaction since
reactivity of the hydrosulfide group in 4 and 7 was
decreased compared to H2S due to its lower acidity and
sterical congestion. Compounds 11 and 12 could also be
obtained by applying a half molar equivalent of H2S to 2
or 2a and 5, respectively. Their formation was indicated
by a transient green coloration after about half portions
of H2S were added to 2 or 5 in the synthesis of 4 and 7,
respectively. Reactions between a titanocene hydrosulfide
and a titanocene alkyl can be used for preparation of
sulfides with different metallocene moieties. This was
exemplified by reacting 7 with 2a, which resulted in the
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(13) Pinkas, J.; Cısarova, I.; Kubista, J.; Horacek, M.; Mach, K.
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~
J. W.; Teuben, J. H. J. Organomet. Chem. 1989, 364, 97–103.
(15) (a) Lukens, W. W., Jr.; Smith, M. R., III; Andersen, R. A. J. Am.
ꢁ ꢀ
ꢁ
Chem. Soc. 1996, 118, 1719–1728. (b) Varga, V.; Cısarova, I.; Gyepes, R.;
ꢁꢀ
ꢀ
Horacek, M.; Kubista, J.; Mach, K. Organometallics 2009, 28, 1748–1757.
ꢁꢀ
ꢀ
(c) Gyepes, R.; Varga, V.; Horacek, M.; Kubista, J.; Pinkas, J.; Mach, K.
Organometallics 2010, 29, 3780–3789.
(16) (a) Bruce, A. E.; Bruce, M. R. M.; Tyler, D. R. J. Am. Chem. Soc.
1984, 106, 6660–6664. (b) Finch, W. C.; Anslyn, E. V.; Grubbs, R. H. J. Am.
Chem. Soc. 1988, 110, 2406–2413.
(17) (a) May, I. W.; Pace, E. L. Spectrochim. Acta A 1968, 24, 1605–
1615. (b) Koga, K.; Takami, A.; Koda, S. Chem. Phys. Lett. 1998, 293, 180–
184.

1038 Organometallics, Vol. 30, No. 5, 2011
Pinkas et al.
formation of [ansa-{(η5-CH2SiMe2C5Me4)2Ti}S(TiCp*2)]
(13) (eq 6).
Scheme 4
only for the less bulky cyclopentadienyl ligands, e.g., Cp0 =
Compounds 11-13 are paramagnetic green crystalline
solids forming bright green toluene solutions. Their EI-MS
spectra showed low-abundant molecular ions for 11 and 13,
whereas for 12 the Mþ ion was not observed at all. The
reason lies in the high temperatures of evaporation, which
facilitate dissociation of the Ti-S bond upon electron im-
pact. Accordingly, the base peaks [Cp*2Ti]þ for 11 and
[(CH2Me2SiC5Me4)2Ti]þ for 13 were observed, and for 12
the [HSiMe2]þ base peak was accompanied with a highly
abundant retro-fragment [5]þ (m/z 431). The IR spectra gave
evidence for the presence of Cp* and (CH2Me2SiC5Me4)2
t
1,3-C5Me3 Bu2 with linear Ti-O-Ti linkage21 or Cp0 =Cp
with the Ti-O-Ti angle of 170.9(4)°.22 The EPR spectrum
of [(Cp2Ti)2O] in toluene glass at 2 K afforded the axially
symmetric triplet-state spectrum (D = 0.0249 cm-1, E = 0)
indicative of the linear Ti-O-Ti arrangement, however.23
In contrast, the rhombic symmetry of the EPR parameters
for 11 proves that the molecule retains the bent structure as
found by X-ray crystallography (see below) in the toluene glass.
The other related compound, the telluride [(Cp*2Ti)2Te] with
˚
the Ti-Te distance of 2.70 A and Ti-Te-Ti angle of
168.62(8)°, surprisingly exerted only a weak magnetic coupling
between the Ti(III) atoms, not displaying the EPR spectra of the
electronic triplet state.24
1
ligands only, and the H NMR spectrum of 11 displayed a
very broad line typical of paramagnetic shift and broad-
ening.
Thermolytic and Photolytic Decomposition of 1 and 4. All
the above hydrosulfides appeared to be thermally unstable at
elevated temperature and photosensitive to sunlight. Heat-
ing of an m-xylene solution of 1 in the dark to 140 °C for 2 h
turned the solution greenish-brown, and pentamethylcyclo-
pentadiene (C5Me5H (Cp*H)), fulvene (C5Me4CH2), and
pentamethylcyclopentadienylthiol (C5Me5SH) were de-
tected in volatiles by GC-MS in the molar ratio ca.
The other spectroscopic properties were discernibly chang-
ing in the order 11 f 13 f 12, reflecting the different
influence of the [Cp*2Ti] and ansa-[(η5-CH2SiMe2C5Me4)2-
Ti] moieties. The green color of the compounds is due to an
absorption band that moves slightly its position from 635 nm
for 11 to 655 nm for 12. The two Ti(III) d1 electrons form
an electronic triplet state of rhombic symmetry, as evidenced
by EPR spectra of their frozen toluene solutions (see Sup-
porting Information). The g-tensor and zero-field splitting
parameters D and E could be determined18 for only 11 (gz=
1.980, gy = 1.967, gx = 1.968; D = 0.01678 cm-1 and E =
0.00163 cm-1), as Ti(III) impurities in 12 and 13 obscured the
central part of their ESR spectra. For 11, a simplified
relationship (eq 7)19 between experimental dipole-dipole
zero-field parameter Dd and
1
12:1.7:1. The H NMR spectra of the thermolytic residue
displayed a number of resonances of apparently C5Me5
ligands, not allowing any conclusion on the thermolytic
products. On the other hand, the solution of 4 in m-xylene
remained clear violet until 150 °C and turned gray at 220 °C
for 5 h with elimination of mainly Cp*H and much less Cp*H
dimers. The EI-MS spectra of the residue after evaporation
of volatiles revealed in addition to the molecular ion of 4 (m/z
351) a pattern of peaks m/z 571-575 and some other high-
mass low-abundant peaks varying with the temperature of
evaporation. Similar spectra were also obtained from the
residue of 1 after 140 °C, not giving any lead to a possible
cluster composition.
Exposure of toluene solutions of 1 and 4 to sunlight
resulted in their color change to brown within 1-2 h. The
photolysis of 1 in C6D6 was followed in a sealed NMR tube:
compound 1 disappeared after 1 h, and Cp*H and H2S were
liberated in approximately equimolar amounts as identified
from 1H and 13C NMR spectra. Unfortunately, a tangle of
1H and 13C NMR resonances attributable to different C5Me5
ligands did not allow determining any titanium-containing
product. The GC-MS analysis of volatiles from photolysis
of 4 revaled the presence of far overwhelming Cp*H.
This indicates that a highly coordinatively unsaturated
[Cp*TiS] species is formed (eq 8), which can stabilize by
"
#
- β2
3R3
2
2
gx þ gy
2
Dd
¼
2gz
þ
ð7Þ
2
˚
˚
the Ti-Ti distance R afforded R=4.66 A, shorter by 0.05 A
than the crystallographic distance. The outer features of the
EPR triplet-state spectra (ΔHzz), which mainly determine the
magnitude of Dd, were slightly increasing in the order 11 f
13 f 12 (364-376 G), whereas the crystallographic Ti-Ti
distances were slightly increasing from an average 4.7117(7)
˚
˚
˚
A for 11 to 4.7476(4) A for 13 and to 4.7701(4) A for 12 (see
below). This disagrees with the inversely proportional rela-
tionship between Dd and R of eq 8; however, differences in
the Ti-Ti distance determined by single-crystal X-ray dif-
fraction and by the EPR method in toluene glass as large as
˚
0.05 A are quite common due to the different molecular
geometry in the glass and in the single crystal.20 It is of
interest that analogous [(Cp02Ti)2O] compounds are known
(21) Sofield, C. D.; Walter, M. D.; Andersen, R. A. Acta Crystallogr.
2004, E60, 1417–1419.
(22) Honold, B.; Thewalt, U.; Herberhold, M.; Alt, H. G.; Kool,
L. B.; Rausch, M. D. J. Organomet. Chem. 1986, 314, 105–111.
(23) Lukens, W. W., Jr.; Andersen, R. A. Inorg. Chem. 1995, 34,
3440–3443.
(18) Wasserman, E.; Snyder, L. C.; Yager, W. A. J. Chem. Phys. 1964,
41, 1763–1772.
(19) Samuel, E.; Harrod, J. F.; Gourier, D.; Dromzee, Y.; Robert, F.;
Jeannin, Y. Inorg. Chem. 1992, 31, 3252–3259.
ꢁꢀ
ꢁ
ꢀ
ꢁ
ꢀ
(20) Horacek, M.; Gyepes, R.; Cısarova, I.; Kubista, J.; Pinkas, J.;
Mach, K. J. Organomet. Chem. 2010, 695, 2338-2344, and references
therein.
(24) Fischer, J. M.; Piers, W. E.; MacGillivray, L. R.; Zaworotko,
M. J. Inorg. Chem. 1995, 34, 2499–2500.

Article
Organometallics, Vol. 30, No. 5, 2011 1039
˚
Table 1. Important Common Bond Lengths (A) and Valence and Dihedral Angles (deg) for Hydrosulfides 4, 1, 7, 8, and [8/6]
4
1
7
8
[8/6]
˚
Bond Lengths (A)
Ti(1)-Cg(1)a
Ti(1)-Cg(2)a
Ti(1)-S(1)
Ti(1)-S(2)
S(1)-H(1)
S(2)-H(2)
2.0618(9)
2.0629(8)
2.3957(6)
2.1323(7)
2.0667(7)
2.0634(7)
2.3958(5)
2.1445(7)
2.1384(7)
2.3984(5)
2.3991(5)
1.167g
2.1424(11)
2.1402(11)
2.4127(8)
2.3910(7)
1.175
2.1359(7)
2.4128(5)
2.4129(4)
1.052
1.210
1.015
1.025
0.928
1.078
Valence Angles (deg)
Cg(1)-Ti(1)-Cg(2)a
Cg(1)-Ti(1)-S(1)
Cg(2)-Ti(1)-S(1)
Cg(1)-Ti(1)-S(2)
Cg(2)-Ti(1)-S(2)
S(1)-Ti-S(2)
143.76(4)
109.32(3)
106.91(3)
137.71(3)
101.77(2)
106.18(2)
102.85(2)
105.21(2)
95.699(17)
101.6
145.12(3)
105.45(2)
109.18(3)
140.37(3)
102.85(3)
102.22(3)
102.09(3)
105.73(3)
95.035(19)
112.7h
140.47(5)
100.48(4)
103.73(4)
105.80(4)
103.42(4)
93.48(3)
101.9
Ti(1)-S(1)-H(1)
Ti(1)-S(2)-H(2)
104.0
107.7
103.1
101.6
103.8
Dihedral Angles (deg)
44.16(4)
jb
36.76(8)
4
-173
36.86(5)
-1
175
46.49(4)
45.01(8)
τ1c
τ2d
ω1e
ω2f
80.96(3)
78.09(3)
69.31(1)i
73.15(1)
42.60(3)
74.28(2)
a Cg(1) and Cg(2) are centroids of the C(1-5) and C(11-15) cyclopentadienyl rings, respectively. b Dihedral angle between the least-squares planes of
cyclopentadienyl rings. c Torsion angle Cg(1)-Ti(1)-S(1)-H(1). d Torsion angle Cg(2)-Ti(1)-S(1)-H(1). e Dihedral angle between the plane defined
by Ti(1), S(1), and S(2) and the plane defined by Ti(1), S(1), and H(1). f Dihedral angle between the plane defined by Ti(1), S(1), and S(2) and the plane
defined by Ti(1), S(2), and H(2). g Atom H(1) is resolved in two orthogonal positions, H(11) and H(12). The distance S(1)-H(11) is given in the table;
Si(1)-H(12) is 1.176 A. h The value for Ti(1)-S(1)-H(11); Ti(1)-S(1)-H(12) is 100.8°. i The dihedral angle involving the Ti(1)-S(1)-H(11) plane; the
˚
dihedral angle involving the Ti(1)-S(1)-H(12) plane is 53.80(1)°.
constituting various clusters using μ-S or μ3-S bridging
atoms.
ν
ꢀ
ꢀ
ꢀ
Cp 2TiSH f Cp H þ ½Cp TiSꢁ
ð8Þ
Compound 1 affords probably the same [Cp*TiS] species,
however, in a more complex process since the established
elimination of Cp*H and H2S would result in a proton-
deficient species. Nevertheless, the formation of [Cp*TiS]
seems to be justified by a serendipitous finding of several
crystals of the tetramer [Cp*Ti(μ3-S)]4 (14), which grew up
from a hexane solution of 3 mixed, accidentally, with only
about one tenth of a molar equivalent of H2S after 16 months
standing in a laboratory shelf (Scheme 4).
The structure of 14 was determined by single-crystal X-ray
diffraction analysis (see below), and the composition was
corroborated by EI-MS spectra revealing the molecular ion
(m/z 860) and plausible fragment ions corresponding to
elimination of Cp*, 2 Cp*H, 3 Cp*H, and M2þ ion (m/z
430). Diamagnetism of 14 and equivalency of all Cp* ligands
was established by 1H and 13C NMR spectra exhibiting one
single resonance for protons and two resonances of carbon
atoms. The mechanism of formation of 14 remains unclear
since its NMR signals were not observed in the above
thermolytic as well as photolytic products of 1. We suggest
that 14 was formed from 1 (arisen from 3, Scheme 1) under
diffuse light on a laboratory shelf. The photolytically liber-
ated H2S was apparently consumed with excess 3 to give 1,
which was photolyzed until its complete disappearance with
elimination of Cp*H. This was proved by GC-MS of vola-
tiles from the mother liquor. The structurally similar cluster
[{(η5-C5H4Me)Ti(μ3-S)}4] was prepared by the reaction of
[(C5H4Me)TiCl2(THF)2] with an equimolar amount of
Figure 1. PLATON drawing of compound 4 at the 30% prob-
ability level with atom-labeling scheme. The hydrogens on
carbon atoms are omitted for clarity.
(Me3Si)2S, eliminating Me3SiCl. The cluster formation was
proposed to proceed via the dimer [(C5H4Me)TiS]2 solvated
with THF.25 Here, the formation of crystalline 14 in hexane,
in which it is practically insoluble, was apparently condi-
tioned by a very slow photolysis of 1, generating a very low
concentration of the [Cp*TiS] species. Attempts to repro-
duce the preparation of 14 in sunlight or by heating to
thermolytic temperature of 1 (140 °C) were unsuccessful.
Crystal Structures. All the prepared crystalline com-
pounds were characterized by single-crystal X-ray diffrac-
tion methods. Important geometric parameters for tita-
nocene hydrosulfides 1, 4, 7, and 8 and composed crystal
[8/6] are listed in Table 1. The monohydrosulfides 4 (Figure 1)
(25) Darkwa, J.; Lockmeyer, J. R.; Boyd, P. D. W.; Rauchfuss, T. B.;
Rheingold, A. L. J. Am. Chem. Soc. 1988, 110, 141–149.

1040 Organometallics, Vol. 30, No. 5, 2011
Pinkas et al.
Figure 5. PLATON drawing of compounds 6 and 8 in [8/6] at
the 30% probability level with atom-labeling scheme. The
hydrogens on carbon atoms except those on C43 and C44 are
omitted for clarity.
Figure 2. PLATON drawing of compound 7 at the 30% prob-
ability level with atom-labeling scheme. The hydrogens on
carbon atoms are omitted for clarity.
Figure 6. PLATON drawing of compound 11 at the 30%
probability level with atom-labeling scheme. Hydrogens are
omitted for clarity.
Figure 3. PLATON drawing of compound 1 at the 30% prob-
ability level with atom-labeling scheme. The hydrogens on
carbon atoms are omitted for clarity.
Figure 7. PLATON drawing of compound 12 at the 30%
probability level with atom-labeling scheme. Hydrogens are
omitted for clarity.
S-H bonds were always found on difference Fourier maps;
however, their position was not refined since a large electron
density from the sulfur atom in the vicinity of hydrogen
Figure 4. PLATON drawing of compound 8 at the 30% prob-
ability level with atom-labeling scheme. The hydrogen H1 is
disordered over two positions (H11, H12) with equal occupancy
factors. The hydrogens on carbon atoms are omitted for clarity.
˚
resulted in an unrealistic short distance (close to 1.0 A)
(Table 1). In spite of this limitation it was established that
the Ti-S-H angles of slightly above 100° are orientated
close to the Cg(1)-Ti-Cg(2) plane (see values of τ for 4 and
7) and ω for 1, 8, and [8/6] (Table 1). This orientation of the
Ti-S-H moiety causes a decrease of the Ti-S bond from the
axis of the Cg(1)-Ti-Cg(2) angle to gain a somewhat larger
space for the S-H bond. For 1, the variation in spatial
orientation of S-H bonds leads to an extensive polymor-
phism. In addition to the monoclinic crystal of 1 described in
Table 1, an orthorhombic crystal (1a) described in detail in
the Supporting Information was also obtained by crystallization
and 7 (Figure 2) with trigonally coordinated titanium(III)
show considerably stronger bonding of cyclopentadienyl
ligands than the tetrahedrally coordinated titanium(IV) di-
hydrosulfides 1 (Figure 3) and 8 (Figures 4 and 5), as indic-
˚
ated by about 0.06 A shorter Ti-Cg bonds.
A discernibly shorter Ti-S bond is found for 4 compared
to 1; however, for the ansa-compounds 7 and 8 the difference
is close to a three-times esd only. The hydrogen atoms in

Article
Organometallics, Vol. 30, No. 5, 2011 1041
Figure 8. PLATON drawing of compound 13 at the 30%
probability level with atom-labeling scheme. Hydrogens are
omitted for clarity.
Figure 9. PLATON drawing of compound 14 at the 30%
probability level with atom-labeling scheme. The carbon atoms
of methyl moieties are disordered into two positions. Hydrogens
are omitted for clarity.
˚
Table 2. Important Common Bond Lengths (A) and Valence and
Dihedral Angles (deg) for Sulfides 11-13
11a
Bond Lengths (A)
12b
13
˚
from the same solvent (hexane), probably at somewhat
different temperature. The unit cell of 1a contained the two
independent molecules, one with the S-H bonds on one side
of the Ti, S(1), S(2) plane and the other with the S-H bonds
on both sides. Nonetheless, Bottomley et al.9a described
Ti(1)-Cg(1)c
Ti(1)-Cg(2)c
Ti(2)-Cg(3)c
Ti(2)-Cg(4)c
Ti(1)-S(1)
2.0944(13)
2.0990(15)
2.0990(13)
2.0994(14)
2.1056(13)
2.1016(13)
2.1045(14)
2.1077(13)
2.3604(8)
2.3589(8)
2.3524(8)
2.3634(8)
4.7069(7)
4.7165(7)
2.1145(7)
2.0937(7)
2.1015(7)
2.0860(8)
2.1096(7)
2.1062(8)
2.3772(4)
2.3806(4)
4.7476(4)
˚
another, tetragonal structure of 1 (I41/a, a,b=31.140(6) A,
3
˚
˚
c=8.350(1) A, Z=16, V=8097(2) A ) with the hydrogen
atoms on opposite sides of the Ti, S(1), S(2) plane and ω
angles about 65°, and mentioned yet another monoclinic
structure (Cm, a=8.202(1) A, b=14.941(1) A, c=9.255(1)
A, β=116.29(1)°, and Z=2). Different positions of the S-H
2.3942(3)
4.7701(4)
˚
˚
Ti(2)-S(1)
˚
bonds were also found for 8 and [8/6]. In 8 the S(1)-H(1)
bond was disordered on both sides of the plane as H(11) and
H(12) (Figure 4), witnessing close probability of occurrence
of any of the two orientations. For [8/6] the S-H bonds in 8
were found on opposite sides of the Ti, S(1), S(2) plane, and
the molecule of 6 did not differ remarkably from that
recently described (Figure 5).13
The sulfides 11-13 (Figures 6-8) contain trigonally co-
ordinated Ti(III) atoms bonded to the sulfur atom in near-
linear arrangements.
The geometric parameters gathered in Table 2 show that
the structures of 11-13 differ negligibly. The Ti-Cg dis-
tances for 11 and 12 are discernibly longer compared to those
for titanocene(TiIII) hydrosulfides 4 and 7, and the Cg-
Ti-Cg angles are more acute, however, very similar for all
11-13 compounds. The Ti-S bonds are becoming slightly
longer and the Ti-S-Ti angles marginally less obtuse in the
order 11 < 13 < 12. In the same order the Ti-Ti distance as
well as the sum of Ti-S distances are increasing. The
conformation of the ansa-[(η5-CH2SiMe2C5Me4)2Ti] species
in a number of complexes has been recently discussed.13 The
staggered conformation of the Cp*2Ti mioety and substan-
tial deviation of the Cp* methyl groups from the ring least-
squares plane are common here and in all known structures
of Cp*2Ti complexes.15
Ti(1)-Ti(2)
Valence Angles (deg)
Cg(1)-Ti(1)-Cg(2)c
Cg(3)-Ti(2)-Cg(4)c
Cg(1)-Ti(1)-S(1)
Cg(2)-Ti(1)-S(1)
Cg(3)-Ti(2)-S(1)
Cg(4)-Ti(2)-S(1)
Ti(1)-S(1)-Ti(2)
138.87(5)
139.16(6)
139.26(5)
138.76(5)
110.87(4)
110.58(5)
110.26(4)
110.26(4)
109.91(5)
110.73(4)
110.78(4)
110.50(4)
174.37(4)
174.33(4)
138.83(3)
139.06(3)
137.98(3)
111.49(3)
109.34(2)
110.75(3)
111.27(3)
172.479(19)
112.25(3)
108.77(2)
169.97(3)
Dihedral Angles (deg)
j1d
j2e
ωf
39.69(11)
39.85(12)
39.91(12)
39.72(10)
85.99(12)
87.72(11)
41.10(7)
40.96(8)
40.40(8)
89.91(9)
88.27(8)
a Data for two nonequivalent molecules in the unit cell: molecule 1
and molecule 2. b Symmetry operation used to generate equivalent
positions: -x þ 1, y, -z þ 1/2. c Cg(1) and Cg(2) are centroids of the
C(1-5) and C(11-15) cyclopentadienyl rings, respectively, and Cg(3)
and Cg(4) are centroids of the C(21-25) and C(31-35) cyclopentadienyl
rings, respectively. d Dihedral angle between the least-squares planes of
the C(1-5) and C(11-15) cyclopentadienyl rings. e Dihedral angle
between the least-squares planes of the C(21-25) and C(31-35) cyclo-
pentadienyl rings. f Dihedral angle between the plane defined by Cg(1),
Ti(1), and Cg(2) and the plane Cg(3), Ti(2), and Cg(4).
The cluster 14 is formed from four equivalent [Cp*Ti(μ3-
S)] moieties forming a distorted cubane structure composed
of Ti and S atoms (Figure 9). The Cp* ligands are rotation-
ally disordered, which resulted in larger thermal parameters
of its ring carbon atoms and resolution of the methyl carbon
atoms into two positions. The least-squares plane of the

1042 Organometallics, Vol. 30, No. 5, 2011
Pinkas et al.
cyclopentadienyl ring C(1-5) is nearly parallel with the
plane of three sulfur atoms (S(1), S(1a), and S(1b)) attached
to the common Ti(1) atom (dihedral angle of 1.22(20)°). The
equivalent positions of the (C5Me5)Ti(1)S(1) moiety are
formed by symmetry operations -x þ 1, -y, z (atoms
denoted 1a), -x þ 1/2, y þ 1/2, -z þ 1/2 (atoms denoted
1b), and x - 1/2, -y þ 1/2, -z þ 1/2 (atoms denoted 1c). The
NMR spectra were recorded on a Varian Mercury 300 spectrom-
eter in C6D6 solutions at 25 °C. Chemical shifts (δ/ppm) are
given relative to solvent signals or tetramethylsilane. EI-MS
spectra were measured on a VG-7070E mass spectrometer at
70 eV. The crystalline samples in sealed capillaries were opened
and inserted into a direct inlet probe under argon. IR spectra of
samples in KBr pellets were measured in an air-protecting
cuvette on a Nicolet Avatar FT IR spectrometer in the range
400-4000 cm-1. KBr pellets were prepared in a Labmaster 130
(mBraun) glovebox under purified nitrogen. X-Band ESR
spectra were recorded on an ERS-220 spectrometer (Center
for Production of Scientific Instruments, Academy of Sciences
˚
bond length Ti(1)-S(1) is 2.3748(9) A, Ti(1)-S(1a) and
˚
Ti(1a)-S(1) are identical (2.3811(9) A), and the same is true
˚
for Ti(1)-S(1b) and Ti(1c)-S(1) bonds (2.3999(9) A). The
valence angles S-Ti-S are 99.73(3)-101.98(3)° and
Ti-S-Ti are 77.04(3)-78.47(3)°. The Ti-Ti distances in
of GDR, Berlin, Germany) operated by
a CU-1 unit
˚
(Magnettech, Berlin, Germany). g-Values were determined by
using an Mn2þ standard at g = 1.9860 (MI = -1/2 line). A
variable-temperature STT-3 unit was used for measurements in
the range -140 to þ25 °C. UV-near-IR spectra in the range
300-2000 nm were measured on a Varian Cary 17D spectro-
meter in sealed quartz cells (Hellma). GC-MS measurements
were performed on a Thermo Focus DSQ using a Thermo TR-
5MS (15 m ꢂ 0.25 mm i.d. ꢂ 0.25 μm) capillary column.
Elemental analyses were carried out on a FLASH EA1112
CHN/O automatic elemental analyzer (Thermo Scientific).
Melting points were measured on a Koffler block in sealed glass
capillaries under nitrogen and are uncorrected. These melting
points should be taken with caution since the observed sample
darkening for 1 and 4 can indicate the photoinduced decom-
position on the Koffler block. Photolysis experiments were
performed in summer with sunlight that passed through 2 ꢂ
2.5 mm glass windows and 2 mm Pyrex glass of the ampule.
Chemicals. The solvents hexane, toluene, and benzene-d6 were
dried by refluxing over LiAlH4 and stored as solutions of dimeric
titanocene [(μ-η5:η5-C5H4C5H4)(μ-H)2{Ti(η5-C5H5)}2].29 Com-
pound 2 and [Cp*2TiMe] (2a) were obtained from [Cp*2TiCl2]
(Aldrich) as described elsewhere.11c Compound 3 was prepared
from [Cp*2Ti(η2-Me3SiCtCSiMe3)] (3a) as reported.12b The tita-
nocene dichloride ansa-[TiCl2(η5-CH2SiMe2C5Me4)2]30 was used
for obtaining ansa-[Ti(III){η1:η5:η5-C5Me4SiMe2CHCH2SiMe2-
C5Me4}] (5) and [Ti(II){η2:η5:η5-C5Me4SiMe2CHdCHSiMe2-
C5Me4}] (6) as described recently.13 H2S was obtained by
hydrolysis of aluminum sulfide (Al2S3) (granular, <4 mesh,
Aldrich) as follows. Granular Al2S3 (3.0 g, 20 mmol) was
degassed in an ampule (2 L) on a vacuum line, and degassed
water (0.18 mL, 10.0 mmol) was condensed in under cooling
with liquid nitrogen. After sealing off, the aluminum sulfide was
repeatedly spread over the ampule and poured into the bottom,
where also all volatiles were condensed. After 2 days the gaseous
H2S was transferred into a storage ampule (5 L) on a vacuum
line by condensing at -196 °C. The reactor line was equipped
with a mercury manometer, allowing dosing of requested
amounts of H2S to the reagent solution (Hg was exposed to
H2S only for the time to restore the pressure of up to 30 Torr).
Preparation of [Cp*2TiSH] (4). Gaseous H2S (total amount of
1.2 mmol) was slowly added to a solution of 2 (0.25 g, 0.8 mmol)
in 5 mL of toluene under stirring. The purple color of 2 turned
intense green when about one-half of the H2S was consumed;
however, addition of the whole amount of H2S by condensing at
liquid nitrogen temperature followed by warming to room
temperature resulted in obtaining a clear violet solution. The
unreacted H2S and all volatiles were immediately evaporated
under vacuum to a trap cooled with liquid nitrogen, and
the violet residue was dissolved in ca. 5 mL of hexane. Crystal-
lization from a concentrated solution at -28 °C yielded violet
crystalline aggregates. Yield: 0.23g (83%). Slow recrystallization
the cluster molecule are 2.9776(8)-3.0081(9) A. These ge-
ometry parameters do not differ from those for [η5-
C5H4Me)Ti(μ3-S)]4 more than by 3-times esd. This allows
us to adopt conclusions of T. B. Rauchfuss and A. L.
Rheingold et al.25 for bonding in 14: four titanium(III)-based
electrons are delocalized in the cluster with participation of
electron-deficient Ti-Ti bonds.
Conclusions
The reaction of hydrogen sulfide with low-valent per-
methyltitanocene derivatives affords a clean and convenient
access to corresponding titanocene hydrosulfides 1, 4, 7, and
8, whose further chemistry can be a subject of interest. The
S-H bonds of 4 and 7 were shown to be highly reactive in
protolysis of Ti-C bonds, affording dititanocene sulfides
11-13, and this gives a good prospect for their reactivity in
hydrothiolation of alkynes. The mode of terminal acetylene
insertion will be of relevance to the recently reported inser-
tion of the HCtCR triple bond into the Zr-SR0 bond in a
catalytic cycle effecting the catalytic hydrothiolation of terminal
alkynes, yielding Markovnikov products.26 Although the sulfur
atoms in the S-H bonds are more sterically hindered and
weaker electron donors than those in nonsubstituted titanocene
hydrosulfides, they should be attempted for the synthesis of
titanium-late transition metal complexes following the metho-
dology known for [Cp2Ti(SH)2].7d,f-h A decreased electroposi-
tivity of titanium in the Cp*Ti moiety could be used to tune the
catalytic properties of such complexes.27 Similarly, titanocene
thiolates can be used to coordinate late transition metal
complexes;28 however, the steric congestion in permethyltitano-
cene thiolates would require using half-sandwich titanocene
thiolates instead. An easy photodecomposition of 1 and 4 is
being explored in the search for new cluster complexes contain-
ing [Cp*TiS] building units.
Experimental Section
General Considerations. Reactions with Ti(III) and Ti(II)
complexes with H2S were performed with exclusion of direct
sunlight in sealed glass devices equipped with breakable seals on
a vacuum line. This was operated by metal valves and finally
driven by active charcoal at -196 °C to give a pressure of about
2 ꢂ 10-4 Torr. 1H (300 MHz), 13C (75 MHz), and 29Si (59.6 MHz)
(26) Weiss, C. J.; Marks, T. J. J. Am. Chem. Soc. 2010, 132, 10533–
10546.
ꢁ
(27) (a) Casado, M. A.; Perez-Torrente, J. J.; Ciriano, M. A.; Oro,
ꢁ
L. A.; Orejon, A.; Carmen, C. Organometallics 1999, 18, 3035–3044.
ꢁ
(b) Casado, M. A.; Perez-Torrente, J. J.; Ciriano, M. A.; Dobrinovitch, I. T.;
Lahoz, F. J.; Oro, L. A. Inorg. Chem. 2003, 42, 3956–3964. (c) Hernandez-
ꢁ
ꢁ
ꢀ
(29) Antropiusova, H.; Dosedlova, A.; Hanus, V.; Mach, K. Transi-
ꢁ
Gruel, M. A. F.; Perez-Torrente, J. J.; Ciriano, M. A.; Rivas, A. B.; Lahoz,
tion Met. Chem. (London) 1981, 6, 90–93.
ꢀ
ꢁ
ꢁꢀ
F. J.; Dobrinovitch, I. T.; Oro, L. A. Organometallics 2003, 22, 1237–1249.
(28) Stephan, D. W.; Nadasdi, T. T. Coord. Chem. Rev. 1996, 147,
147-208, and references therein.
(30) Lukesova, L.; Gyepes, R.; Varga, V.; Pinkas, J.; Horacek, M.;
ꢀ
Kubista, J.; Mach, K. Collect. Czech. Chem. Commun. 2006, 71, 164–
178.

Article
Organometallics, Vol. 30, No. 5, 2011 1043
from hexane afforded crystals suitable for X-ray diffraction
analysis.
mL of toluene under cooling with liquid nitrogen. After warm-
ing to room temperature a stirred solution turned ocher-red
within 20 min. Then all volatiles were distilled at finally 60 °C
under vacuum into a cooled trap, and the residue was dissolved
in hexane. Ocher-red crystalline 1 was obtained from a saturated
solution by cooling to -28 °C. Yield: 0.32 g (85%). The crystal-
line product gave virtually identical 1H and 13C NMR spectra in
C6D6 as 1. The GC-MS analysis of the volatiles established the
presence of 1,2-bis(trimethylsilyl)ethenes (m/z 172).
Data for 4 are as follows. Mp: violet crystals turned brown at
168 °C, melting at 205-210 °C. EI-MS (140 °C): m/z (relative
abundance) 352 (30), 351 (Mþ; 72), 350 (12), 335 ([M - MeH]þ;
6), 319 (26), 318 ([M - SH]þ; 100), 317 ([M - SH2]þ; 95), 316
(30), 315 (38), 313 (14), 217 (19), 216 (18), 215 ([M - Cp*H]þ;
32), 214 (24), 213 (26), 212 ([M - Cp*H - 3 H]þ; 30), 211 (15),
210 (15), 209 (15), 183 (12), 182 (16), 181 ([M - Cp*H - SH2]þ;
26), 180 (19), 179 (18), 178 ([M - Cp*H - 3 H - SH2]þ; 31), 177
(22), 176 (17), 135 ([Cp*]þ; 12), 121 (14), 119 (36), 117 (15), 105
(31), 93 (19), 91 (31), 80 (18), 77 (21). IR (KBr, cm-1): 2968 (s),
2940 (s), 2905 (vs), 2858 (s), 2721 (vw), 2606 (vw) ν(S-H), 1488
(m), 1433 (m,b), 1378 (vs), 1243 (vw), 1160 (vw), 1064 (w), 1023
Preparation of ansa-[(η5-CH2SiMe2C5Me4)2TiSH] (7). Com-
pound 5 (0.61 g, 1.41 mmol) was dissolved in 10 mL of toluene,
giving a brown solution, and gaseous H2S (1.5 mmol) was
condensed in under cooling with liquid nitrogen. After warming
to room temperature a clear blue solution was formed. After 30
min, all volatiles were evaporated to dryness, and the residue
was dissolved in 10 mL of hexane and crystallized from a satu-
rated solution at -28 °C. A blue crystalline solid was separated
from a brown mother liquor and recrystallized analogously
from hexane to give blue rhomboid crystals. Yield: 0.51 g (78%).
Data for 7 are as follows. Mp: decomposition at 185 °C. EI-
MS (180 °C): m/z (relative abundance) 468 (9), 467 (25), 466 (34),
465 (Mþ ; 80), 464 (12), 463 (12), 433 (7), 432 (14), 431 ([M -
H2S]þ; 17), 430 (9), 429 (53), 428 (42), 427 ([M - H2S - 2H2]þ;
74), 426 (40), 425 (22), 259 (7), 258 (15), 257 (10), 244 (7), 243 (8),
242 (11), 241 (15), 240 (9), 163 (10), 119 (19), 105 (10), 85 (21), 73
([SiMe3]þ; 89), 59 ([SiMe2H]þ; 100). IR (KBr, cm-1): 2974 (m),
2947 (s), 2920 (s), 2900 (s), 2866 (m), 2799 (w), 2729 (vw), 2607
(w) ν(S-H), 1481 (w), 1450 (w), 1432 (w), 1412 (w), 1388 (w),
1378 (m), 1349 (w), 1331 (s), 1246 (s), 1130 (w), 1078 (vw), 1022
(m), 830 (vs),797 (m), 766 (s), 709 (m), 682 (m), 594 (m), 572 (w),
444 (m). EPR (toluene, 22 °C): g=1.966, ΔH=7 G; (toluene, -140
°C): g1=2.000, g2=1.984, g3=1.918, gav=1.967. UV-vis (toluene,
nm): 350 (sh) . 547 > 666 (sh). Anal. Calcd for C24H41SSi2Ti
(465.71): C, 61.90; H, 8.87. Found: C, 61.96; H, 8.94.
1
(m), 951 (vw), 802 (vw), 433 (s). H NMR (C6D6): 17.6 (br s,
1900 Hz, 30H, C5Me5); SH not found. EPR (toluene): giso =
1.964, ΔH=14 G; (toluene, -140 °C): g1 =2.000, g2 =1.983,
g3=1.912, gav=1.965. UV-vis (toluene, nm): 545 > 670 (sh).
Anal. Calcd for C20H31STi (351.41): C, 68.36; H, 8.89. Found:
C, 68.42; H, 8.93.
Preparation of 4 from Cp*2TiMe (2a). Cp*2TiMe (0.22 g, 0.66
mmol) was dissolved in C6D6 (2.0 mL), and gaseous H2S (∼0.3
mmol) was condensed to the frozen solution at -196 °C. After
warming to room temperature an intense bright green solution
was formed (of apparently compound 11). Volatiles were con-
densed into an NMR tube under cooling with liquid nitrogen,
and the tube was sealed off. The green solid was dissolved in
toluene (5 mL), and about 0.5 mmol of gaseous H2S was
condensed in. After warming to room temperature, the solution
turned intense blue. After a 5 min warming to 40 °C, all volatiles
were condensed to a trap cooled to -196 °C. The residue was
dissolved in 2 mL of hexane and crystallized by slow distillation
of the solvent in a refrigerator. A residual mother liquor (ca. 0.3
mL) was removed, and fine violet crystals were washed with
condensing hexane vapor and dried under vacuum. Yield: 0.19 g
(82%). The crystals gave virtually identical EI-MS, IR, EPR, and
UV-vis spectra to those of 4. The collected volatiles in C6D6
contained methane as identified by an NMR singlet signal at δH
0.16 ppm31 and H2S at δH 0.18 ppm (published value 0.20 ppm).3b
Preparation of [Cp*2Ti(SH)2] (1). Gaseous H2S (1.2 mmol)
was condensed to a blue solution of 3 (0.32 g, 1.0 mmol) in 10 mL
of toluene under cooling with liquid nitrogen. After warming to
room temperature a stirred solution was warmed to 60 °C for
10 min, changing color to ocher-red. Then all volatiles were
evaporated under vacuum, and the residue was dissolved in
hexane. An ocher-red crystalline solid was obtained from a
saturated solution by cooling to -28 °C. Yield: 0.34 g (89%).
Data for 1 are as follows. Mp: darkening at 210 °C, melting at
Preparation of ansa-[(η5-CH2SiMe2C5Me4)2Ti(SH)2] (8).
Compound 6 (0.34 g, 0.80 mmol) was dissolved in 20 mL of
toluene to give a yellow-orange solution, and gaseous H2S (∼1.9
mmol) was condensed in under cooling with liquid nitrogen.
When the reaction solution warmed to room temperature, it
turned bright red. All volatiles were evaporated under vacuum,
and the residue was dissolved in 20 mL of warm hexane. Slow
cooling to -5 °C yielded a crop of red crystals. A concentrated
mother liquor afforded another crop of crystals of the same
appearance. Combined yield: 0.33 g (0.83%).
Data for 8 are as follows. Mp: 170 °C. 1H NMR (C6D6): 0.17
(s, 12H, SiMe2); 0.95 (s, 4H, SiCH2); 2.03, 2.08 (2 ꢂ s, 2 ꢂ 12H,
C5Me4); 2.93 (s, 2H, SH). 13C{1H} NMR (C6D6): 1.54 (SiMe2),
12.70 (SiCH2); 14.14, 16.83 (C5Me4); 113.18 (Cipso), 130.10,
132.09 (C5Me4). 29Si{1H} NMR (C6D6): -4.91 (SiMe2). EI-
MS (160 °C): m/z (relative abundance) 498 (Mþ 3 ; 5), 497 (6), 496
([M - 2H]þ; 10), 469 (8), 468 (7), 467 (14), 466 (27), 465 ([M -
SH]þ; 35), 464 (28), 463 (14), 433(10), 432 ([M - 2 SH]þ; 25), 431
(10), 429 (19), 428 (13), 427 ([M - 2 SH - 5 H]þ; 23), 379 (12),
258 (17), 257 (11), 241 (14), 179 (9), 178 (7), 177 (10), 145 (23),
143 (15), 119 (18), 105 (17), 91 (7), 85 (22), 73 ([SiMe3]þ; 86), 59
([SiMe2H]þ; 100). IR (KBr, cm-1): 2978 (m), 2950 (m), 2921 (s),
2900 (s), 2851 (m), 2796 (w), 2723 (vw), 2590 (w) ν(S-H), 1474
(m), 1454 (m), 1413 (m), 1375 (m), 1346 (w), 1328 (m), 1254 (s),
1243 (s), 1145 (vw), 1126 (m), 1087 (vw), 1065 (w), 1018 (m), 951
(vw), 836 (vs), 800 (m), 768 (s), 703 (m), 683 (w), 660 (vw),
636 (vw), 598 (m), 578 (vw), 457 (m), 434 (w). Anal. Calcd for
C24H42S2Si2Ti (498.78): C, 57.79; H, 8.49. Found: C, 57.86; H,
8.54.
1
325 °C, brown liquid. H NMR (C6D6): 1.84 (s, 30H, C5Me5);
2.85 (s, 2H, SH). 13C{1H} NMR (C6D6): 12.99 (C5Me5); 122.54
(C5Me5). EI-MS (200 °C): m/z (relative abundance) 384 (Mþ
;
3
2), 382 ([M - 2H]þ; 8), 355 (10), 354 (12), 353 (38), 352 (35), 351
([M - SH]þ; 56), 350 (47), 349 (24), 348 (10), 319 (21), 318 ([M -
2 SH]þ; 53), 317 (42), 316 (18), 315 (15), 253 (18), 251 (23), 249
([M - Cp*]þ; 37), 219 (13), 218 (25), 217 (40), 216 (41), 215
([M - Cp* - H2S]þ; 73), 214 (26), 213 (49), 212 (31), 211 (19),
209 (15), 182 (11), 181 (30), 179 (13), 178 (23), 177 (18), 137 (12),
136 ([Cp*H]þ; 100), 135 (85), 134 (25), 121 (41), 120 (21), 119
(92), 117 (15), 105 (65), 91 (48), 79 (23), 77 (24). IR (KBr, cm-1):
2980 (m), 2949 (m), 2895 (vs), 2857 (s), 2719 (vw), 2600 (vw)
ν(S-H), 1491 (m), 1432 (s), 1377 (vs), 1309 (vw), 1243 (w), 1160
(vw), 1064 (vw), 1021 (m), 954 (vw), 808 (vw), 600 (vw). UV-vis
(toluene, nm): 490. Anal. Calcd for C20H32S2Ti (384.49): C,
62.25; H, 8.39. Found: C, 62.34; H, 8.34.
Preparation of Composed Crystals [8/6]. Compound 6 (0.43 g,
1.0 mmol) was suspended in 15 mL of hexane to give a pale
yellow solution, and H2S was slowly added under stirring. As the
reaction proceeded, the solid 6 was dissolved until at about 1.0
mmol H2S consumed the solid 6 disappeared while the solution
turned ocher. The solution was evaporated, and an ocher
residue was dissolved in hexane and crystallized by slow cooling
Preparation of 1 from 3a. Gaseous H2S (1.2 mmol) was
condensed to a yellow solution of 3a (0.49 g, 1.0 mmol) in 10
(31) Fulmer, G. R.; Miller, A. J. M.; Sherden, N. H.; Gottlieb, H. E.;
Nudelman, A.; Stoltz, B. M.; Bercaw, J. E.; Goldberg, K. I. Organome-
tallics 2010, 29, 2176–2179.

1044 Organometallics, Vol. 30, No. 5, 2011
Pinkas et al.
to -5 °C. A crop of ocher-red crystals was obtained. After con-
centration of the mother liquor another portion of crystals of the
same appearance was collected. Combined yield: 0.34 g (73%).
The X-ray diffraction analysis revealed that the unit cell con-
tained molecules of 8 and 6 in a 1:1 abundance.
onto crystalline 7 (0.21 g, 0.45 mmol), and the mixture was
stirred at 60 °C for 20 min. A clear green solution was cooled
to -28 °C for 2 days. The mother liquor containing a highly
soluble excess of 2a was separated from a crystalline product.
The latter was recrystallized from warm hexane and dried under
vacuum to give a green crystalline solid. Yield: 0.25 g, (71%).
Crystals suitable for X-ray diffraction analysis were obtained
from a toluene solution.
Data for 13 are as follows. Mp: 240 °C. MS EI-MS (240 °C):
m/z (relative abundance) 782 (Mþ 3 ; 4), 468 (4), 467 (7), 466 (5),
465 ([M - Cp*(C5Me4CH2)Ti]þ; 6), 464 (4), 434 (16), 433 (50),
432 ([M - Cp*2TiS]þ; 100), 431 (36), 430 (14), 429 (12), 319 (19),
318 ([Cp*2Ti]þ; 54), 317 (17), 316 (9), 216 ([Cp*TiSH]þ; 6), 179
(7), 121 (7), 91 (7). IR (KBr, cm-1): 2954 (s), 2904 (vs), 2858
(s), 2717 (vw), 1485 (w), 1459 (w), 1444 (m,b), 1413 (w), 1377
(m), 1332 (m), 1246 (s), 1152 (vw), 1130 (w), 1070 (vw), 1023 (m),
832 (vs), 797 (w), 766 (m), 703 (w), 679 (vw), 595 (vw), 570 (vw),
433 (m). EPR (toluene, 22 °C): impurity 1 (Cp02TiOR): g =
1.978, ΔH=3.4 G; impurity 2 (Cp02TiSR): g=1.967, ΔH=10 G;
Data for [8/6] are as follows. Mp: 161 °C. EI-MS (150 °C): m/z
(relative abundance) [8]þ 498 not observed, 467 (63), 465 ([8 -
3
SH]þ; 95), 463 (11), 465 (30), 433 (51), 432 ([8 - 2 SH]þ; 100), 431
([8 - H2S - HS]þ; 78), 430 ([6]þ 3 ; 13), 429 (22), 428 (22), 427
(29), 426 (55), 425 (24), 119 (13), 105 (32), 91 (15), 85 (8), 83 (15),
73 ([SiMe3]þ; 95), 59 ([SiMe2H]þ; 39). IR (KBr, cm-1): 3040
(vw), 2970 (m,sh), 2953 (m), 2902 (s), 2859 (m), 2800 (w,sh), 2729
(vw), 2593 (vw) ν(S-H), 1476 (w), 1453 (w), 1433 (w), 1418 (w),
1376 (m), 1348 (w), 1328 (m), 1247 (s), 1123 (m), 1064 (vw), 1020
(m), 846 (vs), 801 (m), 767 (s), 704 (m), 682 (w), 662 (m), 642 (w),
598 (w), 575 (vw), 498 (vw), 467 (m), 444 (w). 1H, 13C, and 29Si
NMR spectra revealed the presence of 8 and 613 in equimolar
quantities.
Preparation of [(Cp*2Ti)2S] (11). Compound 4 was prepared
from 2 (0.25 g, 0.8 mmol) and H2S (1 mmol) as described above,
and all volatiles were evaporated. A purple solution of 2 (0.25 g,
0.8 mmol) in 5 mL of toluene was added to the violet solid of 4
under stirring. A bright green solution was obtained after
warming to 60 °C for 15 min. Green prisms of 11 were obtained
after cooling of the concentrated solution to -28 °C. The
mother liquor after its volume reduction afforded crystals of
the same appearance. Combined yield: 0.47 g (88%).
(toluene, -140 °C): electronic triplet state: gz =1.980, ΔHzz
=
372 G, gz=1.980, ΔHyy.= 246 G, gy=1.967, ΔHxx obscured by
impurities, ΔMs= 2: singlet, ΔH = 10 G at g=3.942; impurity
1: g1=2.000, g2=1.985, g3=1.955, gav=1.980; impurity 2: g1=
2.000, g2=1.985, g3=1.919, gav=1.968. UV-vis (toluene, nm):
385 . 550(sh) < 645. Anal. Calcd for C44H70SSi2Ti2 (783.04):
C, 67.49; H, 9.01. Found: C, 67.82; H, 9.08.
Preparation of [(Cp*TiS)4] (14). Compound 3 (0.3 g, 0.95
mmol) in 15 mL of hexane was exposed by an experimental fault
to an unknown, much substoichiometric amount of H2S, and a
dark blue solution was left standing in a sealed ampule. After 16
months in diffuse daylight at room temperature, the presence of
several square-pyramidal crystals of gray-metallic appearance
was observed. The blue mother liquor was separated, and the
crystals were washed with condensing hexane vapor and dried
under vacuum. Yield: 0.03 g (0.035 mmol). Further crystal-
lization from the mother liquor after volume reduction afforded
only pure 3. Volatiles of the mother liquor were distilled under
vacuum into a trap cooled with liquid nitrogen. The GC-MS
analysis of the distillate revealed besides hexanes only the
presence of C5Me5H (m/z 136) and a trace of C5Me5H3 (m/z
138). The nonvolatile residue was dissolved in C6D6 for 1H and
13C NMR analysis. Tangles of weak resonances did not allow
identification of any product except 3, whose spectra are
known.12
Data for 11 are as follows. Mp: decomposition at 340 °C. EI-
MS (270 °C): m/z (relative abundance) 670 (5), 669 (6), 668 (Mþ.
;
11), 601 (6), 573 (8), 352 ([M - Cp*Ti(C5Me3(CH2)2)]þ; 14), 351
([Cp*2TiSH]þ; 10), 320 (12), 319 (58), 318 ([Cp*2Ti]þ; 100), 317
(70), 316 (29), 216 ([Cp*TiSH]þ; 12), 212 (10), 182 (9), 181 (12),
179 (7), 178 (9), 136 (12), 135 (12), 119 (18), 105 (16), 95 (11), 91
(14), 79 (9). IR (KBr, cm-1): 2982 (m,sh), 2966 (m), 2901 (vs),
2858 (s), 2716 (vw), 1491 (w), 1439 (m,b), 1377 (s), 1309 (vw),
1242 (w), 1166 (w), 1064 (vw), 1023 (m). 1H NMR (C6D6): 15.5
(br s, 2600 Hz, 60H, C5Me5). EPR (toluene, 22 °C): giso=1.970,
ΔH = 10 G; (toluene, -140 °C): electronic triplet state gz =
1.980, gy = 1.967, gx =1.969, D = 0.01678 cm-1, E=0.00163
cm-1, ΔMs = 2: singlet, ΔH = 10 G at g = 3.941. UV-vis
(toluene, nm): 372 > 397 (sh) . 550 (sh) < 635. Anal. Calcd for
C40H60STi2 (668.75): C, 71.84; H, 9.04. Found: C, 71.80; H,
8.98.
Preparation of ansa-[{(η5-CH2SiMe2C5Me4)2Ti}2S] (12).
Compound 7 (0.30 g, 0.64 mmol) in 10 mL of toluene was
poured onto solid 5 (0.28 g, 0.64 mmol), and the mixture was
kept at 60 °C for 5 h to give a yellowish-green solution. All
volatiles were evaporated under vacuum, and the residue was
dissolved in 30 mL of hexane at 60 °C. Slow cooling to -5 °C
afforded green, nearly rectangular prisms. Yield: 0.32 g (56%).
Data for 12 are as follows. Mp: decomposition at 185 °C. EI-
Data for 14 are as follows. Mp > 360 °C. EI-MS (340 °C): m/z
(relative abundance) 862 (10), 861 (13), 860 (Mþ 3 ; 16), 859 (9),
725 ([M - Cp*]þ; 2), 679 (13), 678 (8), 677 ([M - Cp*Ti]þ; 13),
661 (10), 455 (10), 430 ([M/2]þ; 6), 368 (11), 279 (13), 278 ([M - 3
Cp*Ti - SH]þ; 67), 256 (10), 219 (9), 185 (13), 170 (12), 157 (16),
141 (9), 136 (10), 135 (13), 133 (10), 131 (10), 129 (12), 121 (14),
119 (16), 97 (9), 96 (9), 83 (11), 81 (10), 69 (38), 57 (26), 55 (31), 51
MS (180 °C): m/z (relative abundance) Mþ 896 not observed,
(12). H NMR (C6D6): 2.56 (s, 60H, C5Me5). 13C{1H} NMR
1
3
465 (17), 464 ([M - Cp02Ti]þ; 16), 463 (11), 433 (16), 432 (45),
431 ([M - Cp02Ti - HS]þ; 75), 430 (27), 429 (40), 428 (32), 427
(25), 426 (10), 119 (12), 105 (17), 91 (12), 85 (19), 83 (27), 73
([SiMe3]þ; 95), 59 ([SiMe2H]þ; 100). IR (KBr, cm-1): 2947 (s,sh),
2919 (vs), 2854 (s), 2800 (w,sh), 1481 (w), 1452 (w), 1410 (w),
1381 (w), 1349 (w), 1331 (m), 1248 (s), 1154 (vw), 1130 (w), 1090
(vw), 1072 (vw), 1024 (m), 832 (vs),799 (m), 766 (s), 706 (m), 681
(w), 595 (w), 571 (vw), 435 (m). EPR (toluene, 22 °C): impurity 1
(Cp02TiOR): g = 1.978, ΔH = 3.3 G, aTi = 7.9 G; impurity 2
(Cp02TiSR): g=1.963, ΔH=13 G; (toluene, -140 °C): electro-
nic triplet state: ΔHzz=376 G, gz=1.981, ΔHyy.= 226 G, gy=
1.969, ΔHxx obscured by impurities, ΔMs = 2: singlet, ΔH =
10 G at g=3.942; impurity 1: g1=2.000, g2=1.984, g3=1.955, gav=
1.980; impurity 2: g1 =2.000, g2=1.984, g3 =1.910, gav =1.965.
UV-vis (toluene, nm): 385 > 420 (sh) . 655. Anal. Calcd for
C48H80SSi4Ti2 (897.34): C, 64.25; H, 8.99. Found: C, 64.18; H, 8.96.
Preparation of [ansa-{(η5-CH2SiMe2C5Me4)2Ti}S(TiCp*2)]
(13). A solution of 2a (0.5 mmol in 4 mL of hexane) was poured
(C6D6): 14.55 (C5Me5); 119.84 (C5Me5). IR (KBr, cm-1): 2971
(m), 2946 (m), 2904 (vs), 2852 (m), 2718 (vw), 1494 (w), 1484 (w),
1454 (m), 1430 (m), 1373 (vs), 1309 (vw), 1244 (w), 1158 (vw),
1064 (vw), 1025 (m), 802 (vw). Anal. Calcd for C40H60S4Ti4
(860.70): C, 55.82; H, 7.03. Found: C, 56.02; H, 6.97.
Thermolysis of 1. A solution of 1 (0.22 g, 0.57 mmol) in m-
xylene (5 mL) was heated to 140 °C for 4 h in an oven, turning the
initial red color to brown. All volatiles were distilled at 100 °C
under high vacuum to a cooled trap and analyzed by GC-MS:
C5Me5H, m/z 136, (92%), fulvene C5Me4CH2, m/z 134, (5%),
C5Me5SH, m/z 168, (3%).
Thermolysis of 4. Compound 4 (0.18 g, 0.5 mmol) was
dissolved in m-xylene (5.0 mL), sealed in a glass ampule, and
subsequently heated. The blue color of 4 faded only after 168 °C,
and the final gray solution was worked up after heating to 250 °C
for 2 h. Volatiles were collected in a cooled trap and analyzed
with GC-MS: m/z 136 (Cp*H) 98%, m/z 270 (Cp*2) 1%, m/z 272
(Cp*H)2 1%. Only a minor part of the nonvolatile residue was

Article
Organometallics, Vol. 30, No. 5, 2011 1045
extracted into hexane. The residue was largely soluble in tol-
uene; however, some black solid remained insoluble. The solu-
purified nitrogen. Diffraction data for all complexes were col-
lected on a Nonius KappaCCD diffractometer (Mo KR radiation,
33
ble fractions gave no crystallizing product, and their 1H and 13
C
λ= 0.71073 A) and processed by the HKL program package.
˚
NMR spectra showed a tangle of resonances for Cp* ligands.
EI-MS spectra (150-250 °C) of the residue from the hexane
extract indicated still the presence of 4þ (m/z 351 and its
fragment ions) and low-intensity peaks at m/z 602, 574, 573,
559, 545, 430, and 414, which could indicate a cluster formation.
Photolysis of 1 in an NMR Tube. A C6D6 solution of 1 (38 mg)
in a sealed NMR tube was exposed to sunlight, and the photo-
lysis progress was followed by 1H NMR spectroscopy. The
signals belonging to 1 vanished within 2 h. The 1H NMR
spectrum of the photolyzed sample contained the resonance of
H2S at δH =0.18 ppm (published value δH =0.20 ppm)3c and
resonances of pentamethylcyclopentadiene32 in integral ratio
close to 1:1. Furthermore, the spectrum showed the presence of
several Cp* moieties, which could not be assigned. Then the
NMR tube was opened under vacuum, and volatiles were
distilled into a trap at 60 °C. The GC-MS analysis revealed
the presence of Cp*H (60%) and fulvene (C5Me4CH2) (40%).
Photolysis of 4 in Benzene. A solution of 4 (0.14 g, 0.4 mmol) in
benzene (5 mL) was exposed to sunlight for 5 h. All volatiles
were distilled under vacuum into a trap cooled to -196 °C, and
after warming to ambient temperature in air the liquid was
analyzed by GC-MS. The products consisted of Cp*H (84%)
and C5Me4CH2 (16%).
The phase problem was solved by direct methods (SIR97),34
followed by consecutive Fourier syntheses, and refined by full-
matrix least-squares on F2 (SHELXL-97).35 Relevant crystallo-
graphic data are gathered in the Supporting Information. All non-
hydrogen atoms were refined anisotropically, except those of
disordered methyl moieties in 14. The C-H hydrogen atoms were
found on a difference Fourier map, recalculated into idealized
positions (riding model), and assigned temperature factors either
Hiso(H) =1.2Ueq(pivot atom) or Hiso(H)=1.5Ueq(pivot atom),
except for H(43) andH(44) of 8/6. Thesewererefinedisotropically
without any restraints. The hydrogenatoms of S-H moieties were
found on difference Fourier maps and refined as riding on
corresponding S atoms with restricted displacement parameters.
PLATON/SQUEEZE36 was used to correct the data of 13 for the
presence of the disordered solvent. One potential solvent volume
3
˚
of 376 A was found at a special position; 103 electrons per unit cell
worth of scattering were located in the void, corresponding well to
two molecules of toluene. Molecular graphics was carried out with
the PLATON program.37
Acknowledgment. This research was supported by the
Grant Agency of the Academy of Sciences of the Czech
Republic (Grant No. IAA400400708) and the Ministry of
Education, Youth and Sports (Project No. LC06070).
I.C. is grateful for MSM0021620857.
X-ray Crystallography. Single crystals or crystal fragments of
1, 1a, 4, 7, 8, 8/6, and 11-14 were mounted into Lindemann
glass capillaries in a Labmaster 130 glovebox (mBraun) under
Supporting Information Available: CIF files for the structures
1, 1a, 4, 7, 8, 8/6, 11, 12, 13, and 14. EPR spectrum of 11 in frozen
toluene glass. Tables of crystallographic data and data collec-
tion and structure refinement details for 1, 1a, 4, 7, 8, 8/6, 11, 12,
13, and 14. This material is available free of charge via the
Internet at http://pubs.acs.org.
ꢀ
(32) Pinkas, J.; Gyepes, R.; Cısarova, I.; Stepnicka, P.; Horacek, M.;
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Kubista, J.; Varga, V.; Mach, K. Collect. Czech. Chem. Commun. 2008,
73, 967–982.
(33) Otwinowski, Z.; Minor, W. HKL Denzo and Scalepack program
package by Nonius. For a reference, see: Otwinowski, Z.; Minor, W.
Methods Enzymol. 1997, 276, 307-326.
(34) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.;
Giacovazzo, C.; Guagliardi, A.; Polidori, G. J. Appl. Crystallogr.
1994, 27, 435–436.
(36) v. d. Sluis, O.; Spek, A. K. Acta Crystallogr., Sect. A: Found.
Crystallogr. 1990, A46, 194–201.
(35) Sheldrick, G. M. SHELXL97, Program for Crystal Structure
€
€
Refinement from Diffraction Data; University of Gottingen: Gottingen,
1997.
(37) Spek, A. L. PLATON, A Multipurpose Crystallographic Tool;
Utrecht University: Utrecht, Netherlands, 2007.