Different inertness of titanocene [Cp2Ti] and decamethyltitanocene [Cp*2Ti] in reactions with N,N-bis(trimethylsilyl)sulfurdiimide - Elimination of tetramethylfulvene and formation of half-titanocene complexes

Article abstract of DOI:10.1002/ejic.201200242

The reaction of the titanocene alkyne complex [Cp* ₂Ti(η²-Me₃SiC₂SiMe₃)] (1) (Cp* = η⁵-pentamethylcyclopentadienyl) with N,N-bis(trimethylsilyl)sulfurdiimide (2) results in the formation of 1,2,3,4-tetramethylfulvene (3) as well as three titanium complexes 4, 5 and 6. During the reaction, formal elimination of one Cp* ligand induces a series of C-H and N-S bond activation steps, thus yielding the products. The molecular structures of complex 5 and of the free fulvene were determined by X-ray crystallographic analysis. Evidently, in these reactions [Cp* ₂Ti] is less stable than [Cp₂Ti]; a possible reason was found to be the well-known intramolecular C-H activation yielding the tautomeric tetramethylfulvene hydride species, from which 1,2,3,4-tetramethylfulvene (3) can dissociate. Reaction of decamethyltitanocene complex [Cp* ₂Ti(η²-Me₃SiC₂SiMe₃)] with N,N-bis(trimethylsilyl)sulfurdiimide results in the formation of three titanium complexes as well as 1,2,3,4-tetramethylfulvene (3) as the organic byproduct. The molecular structures of metallacyclic half-sandwich titanium complex 5 and - most remarkably - of free 3 (co-crystallised with Me ₃SiC₂SiMe₃) were determined by X-ray crystallographic analysis. Copyright

Full text of DOI:10.1002/ejic.201200242

SHORT COMMUNICATION
DOI: 10.1002/ejic.201200242
Different Inertness of Titanocene [Cp2Ti] and Decamethyltitanocene [Cp*2Ti]
in Reactions with N,N-Bis(trimethylsilyl)sulfurdiimide – Elimination of
Tetramethylfulvene and Formation of Half-Titanocene Complexes
Katharina Kaleta,[a] Monty Kessler,[a] Torsten Beweries,*[a] Perdita Arndt,[a]
Anke Spannenberg,[a] and Uwe Rosenthal*[a]
Keywords: C–H activation / Metallacycles / Metallocenes / Titanium / Structure elucidation
The reaction of the titanocene alkyne complex [Cp*2Ti(η2-
Me3SiC2SiMe3)] (1) (Cp* = η5-pentamethylcyclopentadienyl)
with N,N-bis(trimethylsilyl)sulfurdiimide (2) results in the
formation of 1,2,3,4-tetramethylfulvene (3) as well as three
titanium complexes 4, 5 and 6. During the reaction, formal
elimination of one Cp* ligand induces a series of C–H and
N–S bond activation steps, thus yielding the products. The
molecular structures of complex 5 and of the free fulvene
were determined by X-ray crystallographic analysis. Evi-
dently, in these reactions [Cp*2Ti] is less stable than [Cp2Ti];
a possible reason was found to be the well-known intramo-
lecular C–H activation yielding the tautomeric tetrameth-
ylfulvene hydride species, from which 1,2,3,4-tetramethyl-
fulvene (3) can dissociate.
tadienyl), elimination or insertion reactions of the alkyne
were the dominant reaction patterns. However, some exam-
ples of the activation or elimination of the cyclopentadienyl
ligand were observed.[9,10]
Introduction
Since the early days in titanocene[1] and zirconocene[2]
chemistry the [Cp2M] complex fragment (Cp = cyclopen-
tadienyl) was mostly considered to be relatively inert re-
garding the dissociation of Cp ligands: “In most organo-
metallic reactions of transition metal complexes, the η5-Cp
ligand plays the role of a spectator that stays tightly bound
in η5 fashion to the metal centre throughout the course of
the reactions.”[3] Nevertheless, there were some strong hints
from Brintzinger’s results on the elimination of the η5-Cp
ligands during reduction, which motivated his group to in-
troduce the ansa-bridged rac-ebthi [ebthi = 1,2-ethylene-
1,1Ј-bis(η5-tetrahydroindenyl)] ligand to prevent the elimi-
nation of Cp by the chelate effect.[4]
Already in 1974, the photochemically induced exchange
reaction of Cp ligands between different titanocene com-
plexes was observed.[5] Numerous reactions of metallocene
complexes involving the Cp ligand are known; examples in-
clude C–H activation, coupling and ring opening reac-
tions.[6] These “unexpected” activation processes influence
synthetic[7] and catalytic[8] applications and should therefore
be taken into account when using such metallocene com-
plexes. In our studies of the metallocene alkyne complexes
CpЈ2M(L)(η2-Me3SiC2SiMe3) (M = Ti, Zr, Hf; L = thf,
pyridine; CpЈ = substituted or unsubstituted η5-cyclopen-
For the parent fully methylated complex fragment
[Cp*2M] (Cp* = pentamethylcyclopentadienyl), similar ex-
amples for the loss of one Cp* group from the titanium
centre are known. Very recently, in our group such formal
ligand eliminations were found in the reaction of the titano-
cene alkyne complex [Cp*2Ti(η2-Me3SiC2SiMe3)] (1) with
azobenzene[11] or during the irradiation of the decamethyl-
titanocene dihydroxido complex [Cp*2Ti(OH)2], where eli-
mination of a pentamethylcyclopentadienyl radical takes
place.[12] Pentamethylcyclopentadienol and pentamethylcy-
clopentadiene, formed by recombination of Cp*· with OH·
and H· (which were also cleaved off during irradiation),
respectively, were found to be the organic products in this
bond activation reaction.
The unsubstituted complex [Cp2Ti(η2-Me3SiC2SiMe3)]
reacts with N,N-bis(trimethylsilyl)sulfurdiimide (2) with al-
kyne substitution to give a four-membered Ti–N–S–N
metallacycle (A) (Scheme 1).[13] In this earlier paper, we re-
[a] Leibniz-Institut für Katalyse e.V. an der Universität Rostock,
Albert-Einstein-Str. 29a, 18059 Rostock, Germany
Fax: +49-381-1281-51104, -51176
E-mail: torsten.beweries@catalysis.de
uwe.rosenthal@catalysis.de
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201200242.
Scheme 1.
Me3SiN=S=NSiMe3.
Reaction
of
[Cp2Ti(η2-Me3SiC2SiMe3)]
with
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Formation of Half-Titanocene Complexes
ported on the unusual structure and bonding of this hetero- cipitated at –78 °C, which was analysed by mass spec-
metallacycle by means of X-ray diffraction analysis and troscopy and tentatively identified as the titanocene sulfur
DFT calculations.
compound 6. This four-membered metallacycle was first
In this present contribution we describe the reaction of synthesised by Shaver et al. and was isolated as black crys-
the permethylated titanocene alkyne complex [Cp*2Ti(η2- tals.[14] Unfortunately, after filtration of all precipitates, the
Me3SiC2SiMe3)] (1) with N,N-bis(trimethylsilyl)sulfurdi- mother liquor still contains large amounts of the main
imide, thus emphasising the different reactivities of Cp and product 5, which cannot be isolated because of its high sol-
Cp* complexes. As found before, the formal elimination of ubility. Therefore, the isolated yields (overall isolated yield
the pentamethylcyclopentadienyl ligand from the metal cen- of all titanium complexes of 40%) do not reflect the actual
tre was facilitated in contrast to the unsubstituted complex ratio of the compounds produced during the reaction.
[Cp2Ti(η2-Me3SiC2SiMe3)].
Furthermore, the interference of the signals of the different
compounds prevents a quantitative determination by 1H
NMR spectroscopy.
The molecular structure of complex 5 is shown in
Figure 1. The titanium atom is coordinated by one penta-
methylcyclopentadienyl ligand and a trimethylsilyl amino
group and is part of a planar four-membered metallacycle
(N1–Ti1–N3–S1 4.7°). The central sulfur atom is bound to
a trimethylsilyl imido group via a N=S double bond
[1.530(2) Å]. Ti–N as well as N–S distances in the ring unit
are equal and correspond to typical single bonds [Ti–N
1.938(2), N–S 1.703(2) Å]. The Ti–S distance of 2.6761(5) Å
is longer than that in the computed metallacycle A,[15]
which suggests that the presence of an interannular Ti–S
bond can be excluded in complex 5.[13]
Results and Discussion
The reaction of complex 1 with N,N-bis(trimethylsilyl)-
sulfurdiimide (2) was completed after five days at 50 °C,
resulting in a red solution. The alkyne elimination proceeds
via a green paramagnetic intermediate, which could not be
identified. Concerning the H and 13C NMR spectra, sev-
1
eral products were formed reproducibly, which had to be
isolated and characterised. After concentration of the reac-
tion mixture at low temperature, the liquid substances could
be separated by distillation at 70 °C and 0.1 mbar. This re-
sulted in a yellow solution of different amounts of 1,2,3,4-
tetramethylfulvene (3) besides n-hexane, bis(trimethylsilyl)-
acetylene and the starting material N,NЈ-bis(trimethylsilyl)-
sulfurdiimide. Therefore, we conclude that elimination of
a pentamethylcyclopentadienyl fragment of the titanocene
complex takes place in the absence of any reducing agent
or upon irradiation with light (Scheme 2).
From the distillation residue, the organometallic prod-
ucts of this bond activation process could be isolated by
repeated crystallisation from an n-hexane solution at
–78 °C. First, the dinuclear complex 4 was obtained as
1
yellow crystalline material. Its H NMR spectrum displays
resonances due to a Cp* ligand and an amino group
(–NHSiMe3) as well as two different signals corresponding
to SiMe3 protons. Results from elemental analysis and mass
spectrometry {molecular ion peak at m/z = 844 for
[Cp*(NHSiMe3)Ti(NSiMe3)S2]2} further suggest a consti-
tution of complex 4 as shown in Scheme 2. Filtration of the
mother liquor and storing at –78 °C yielded orange crystals
of the mononuclear half-sandwich complex 5, which were
Figure 1. Molecular structure of complex 5. Hydrogen atoms (ex-
cept H4) are omitted for clarity. Thermal ellipsoids correspond to
50% probability.
The sulfur atom adopts a distorted pseudotetrahedral
suitable for X-ray crystallography. Similarly to complex 4, geometry [N1–S1–N3 92.21(7)°, N1–S1–N2 108.54(8)° and
a transfer of a hydrogen atom of one pentamethylcyclopen- N2–S1–N3 110.23(8)°]. The free ligand, a tris(imido)sulfite
tadienyl ligand to an imido group was observed with elimi- S(NSiMe3)3, was synthesised by Pohl et al. and displays a
nation of 1,2,3,4-tetramethylfulvene (3). Finally, from the planar coordination geometry at the S atom with S=N
remaining solution a small amount of a brown solid pre- bond lengths of 1.504(3) Å,[16] slightly shorter than those in
Scheme 2. Reaction of complex 1 with N,NЈ-bis(trimethylsilyl)sulfurdiimide (2).
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T. Beweries, U. Rosenthal et al.
SHORT COMMUNICATION
complex 5. Structural data suggest the presence of a metalla- of the CϵC triple bond with an aromatic hydrogen atom.[20]
cyclic σ complex with the titanium centre in the formal As shown in Figure 3, no interaction of the alkyne with the
oxidation state +4. This is corroborated by its NMR ac- fulvene is observed in this case. Characteristic bond lengths
tivity, showing resonances in its 1H NMR spectrum for the and angles of the bis(trimethylsilyl)acetylene resemble those
SiMe3 groups at δ = 0.05, 0.35 and 0.44 ppm as well as for found in the pure compound [e.g. C1–C1A 1.201(3) Å, cf.
the Cp* protons at δ = 2.01 ppm. A singlet due to the NH C–C 1.208(3) Å in the pure alkyne].[21]
functionality was observed at δ = 6.73 ppm.
Stalke and co-workers synthesised zinc and main group
metal tris(imido)sulfonate salts in which the sulfur atom is
bound to an additional substituent.[17] S–N bond lengths
are similar and in the range 1.50 to 1.60 Å, thus indicating
that an ionic interaction with electron delocalisation
throughout the SN unit is present. Very recently, Gade et
al. reported on the first zirconium complexes of a tris-
(imido)sulfite [S(NSiMe3)2(N-DIPP)] (DIPP = 2,6-diiso-
propylphenyl)andahydrazidobis(imido)sulfite[S(NSiMe3)2-
(NNPh2)], both formed by [2+2] cycloaddition of a sulfur-
diimide with a [LZr=NR] complex.[18] Structural param-
eters of these complexes are similar to those found in com-
plex 5; however, because of unsymmetrical substitution the
S–N distances in the metallacycle are different in Gade’s
complexes. DFT analysis of the structure and bonding in
Figure 3. Crystal packing diagram of 3·BTMSA. Thermal ellip-
the zirconium complexes showed that the electron density
of the ring unit is reduced by the terminal [NSiMe3] group,
which results in a higher polarity of the M–N and N–S
bonds.[18]
soids correspond to 50% probability. Hydrogen atoms are omitted
for clarity.
As shown in Scheme 3, in the crystal of 3·BTMSA two
orientations of the molecule overlap; the methylene group
was found to be half-and-half at C7 and C7A. Therefore,
the bond lengths of C4–C5, C5–C6 and C4–C7 correspond
to values between single and double bonds whereas C4–
C4A is a typical single bond. Compounds containing
fulvene units were described in the literature before, for ex-
ample, 1,2,3,4,6-pentaphenylfulvene.[22]
Most interestingly, we succeeded in the isolation and
characterisation of 1,2,3,4-tetramethylfulvene (3) as the or-
ganic product of the Cp* dissociation process. In many
cases, fulvene formation has been observed in the presence
of basic ligands;[19] however, to the best of our knowledge,
this reaction is one of the few examples in which the formal
elimination of a Cp* ligand such as 3 from the titanium
centre at moderate temperature and without irradiation
with light was proven by isolation of the corresponding C–
H activated product. For the first time, the structure of un-
coordinated 1,2,3,4-tetramethylfulvene was determined by
X-ray crystallography. Yellow crystals of compound
3·BTMSA could be isolated from the crude reaction mix-
ture in n-hexane by cooling to –78 °C. The molecular struc-
ture of the tetramethylfulvene co-crystallised with bis(tri-
methylsilyl)acetylene (BTMSA) is depicted in Figure 2.
Scheme 3. Orientation of the two half overlapping 1,2,3,4-tetra-
methylfulvene molecules formed by symmetry.
The reaction of alkyne complex 1 with N,N-bis(tri-
methylsilyl)sulfurdiimide most likely proceeds by
a
multistep mechanism consisting of several C–H and N–S
bond activation steps. One possibility includes the elimi-
nation of bis(trimethylsilyl)acetylene to form the [Cp*2Ti]
fragment, which undergoes an intramolecular C–H acti-
vation to yield the well-known tautomeric hydride spe-
cies.[23] Subsequent reaction of this species with a [NSiMe3]
group induces an elimination of 1,2,3,4-tetramethylfulvene
(3) by a transfer of the hydrogen atom and formation of the
[Cp*(NHSiMe3)Ti] fragment. The formation of an amido
group could then facilitate the activation of the N=S bond
and cause the cleavage of the sulfurdiimide. Surprisingly,
the activation of the N–Si bond, which is usually favoured
in the reaction of N,NЈ-bis(trimethylsilyl)sulfurdiimide, was
not observed. Finally, the recombination of the amino and
Figure 2. Molecular structure of 3·BTMSA. Thermal ellipsoids
correspond to 50% probability.
Bolte et al. published the solid-state structure of this alk- sulfurimido fragments with the titanocene complexes
yne crystallised with benzene and observed an interaction should result in two different compounds: 4 and 5.
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Formation of Half-Titanocene Complexes
Another likely possibility involves an intermediate sim- was determined by X-ray crystallographic analysis. The
ilar to complex A, which could undergo C–H bond acti- eliminated hydrogen atom was most likely transferred to an
vation to give the free 1,2,3,4-tetramethylfulvene and a half- imido group of the sulfurdiimide, which resulted in the half-
sandwich complex [Cp*Ti(NHSiMe3)(η2-SNSiMe3)]. The sandwich titanium amido complexes 4 and 5. Intramolecu-
latter could get desulfurised to give complex 4 and an imido lar C–H bond activation (Scheme 4) was found to be the
complex [Cp*Ti=NSiMe3(NHSiMe3)]. In a last step, which reason for the formation of the latter species. Similar “ring
is very similar to the [2+2] cycloaddition observed by Gade slippage” processes are also known for Cp ligands;[26] how-
et al.,[18] this could then be coupled to another sulfurdi- ever, in the described reactions with bis(trimethylsilyl)-
imide fragment to give the four-membered heterometalla- sulfurdiimide, this is not as pronounced as in the related
cycle 5. However, these mechanistic considerations remain Cp* complexes. Another possible rationalisation for the
rather speculative; attempts to gain further insight into the more facile activation of the Cp* relative to the Cp ligand
formation of the organometallic products were of limited could be the option of formal elimination as a neutral li-
success: variation of the ratios of the starting materials 1 gand in the former case (vs. as a radical or coupling product
and 2 gave results that are very similar to those obtained for Cp).
with a 1:1 ratio. The reaction was monitored by means of
NMR spectroscopy in order to check whether interconver-
sion between either of the product complexes takes place.
Experimental Section
Unfortunately, no trend could be discerned from analysis
General Information: All operations were carried out under argon
1
of the H NMR spectra (see Supporting Information for
with standard Schlenk techniques or in a glove box. Prior to use,
details).
solvents were freshly distilled from sodium tetraethylaluminate and
stored under argon. Me3SiN=S=NSiMe3
It should be noted that these results match well with the
[27]
and [Cp*2Ti(η2-
Me3SiC2SiMe3)][28] were synthesised according to published pro-
cedures. The following spectrometers were used: MAT 95-XP for
mass spectra, Bruker AV 300 or AV 400 for NMR spectra. Chemi-
cal shifts (1H, 13C) are given in ppm relative to SiMe4 and are
referenced to signals of [D6]benzene (δH = 7.16, δC = 128.0). Melt-
ing points are measured in sealed capillaries with a Büchi 535 appa-
ratus. Elemental analyses were performed with a Leco CHNS-932
elemental analyser.
trend that four-membered strained metallacycles tend to be
stabilised by coordination of a second metal fragment[24a]
or substitution at the central β-atom (carbon or sulfur).[24b]
This phenomenon was discussed by us before for titanocene
carbodiimide complexes and will be the matter of detailed
investigations in future.[25]
Conclusions
Synthesis of Compounds 3, 4, 5 and 6: [Cp*2Ti(η2-Me3SiC2SiMe3)]
(1) (0.345 g, 0.706 mmol) was dissolved in n-hexane (10 mL). N,N-
bis(trimethylsilyl)sulfurdiimide (2) (0.17 mL, 0.706 mmol) was
added, and the reaction mixture turned green. The mixture was
stirred at 50 °C for 5 d, after which a red solution was obtained.
The reaction of the decamethyltitanocene fragment
[Cp*2Ti] with N,N-bis(trimethylsilyl)sulfurdiimide resulted
in a formal dissociation of a Cp* ligand and thus in the
formation of 1,2,3,4-tetramethylfulvene and three different After the amount of solvent was reduced at 0 °C, the remaining
volatiles were distilled at 70 °C and 0.1 mbar to reveal a mixture of
1,2,3,4-tetramethylfulvene (3), n-hexane, bis(trimethylsilyl)acetyl-
ene and N,NЈ-bis(trimethylsilyl)sulfurdiimide. The crude product
was dissolved in n-hexane (2 mL) and stored at –78 °C, whereupon
yellow crystals of dinuclear complex 4 precipitated. They were iso-
lated and washed with cold n-hexane. Yield of 4: 0.090 g
(0.106 mmol, 30% referred to Ti). The mother liquor was again
stored at –78 °C and orange crystals of mononuclear complex 5
were obtained, which were isolated and washed with cold n-hexane.
Yield of 5: 0.032 g (0.057 mmol, 8% referred to Ti). The remaining
solution was cooled to –78 °C. A brown precipitate of 6 could be
isolated and washed with cold n-hexane. Yield of 6: approximately
0.005 g (ca. 2% based on Ti). Single crystals of 3 [co-crystallised
with bis(trimethylsilyl)acetylene] and 5 suitable for X-ray analysis
were obtained from a portion of the crude reaction mixture that
was stored at –78 °C.
titanium complexes. Again, significant differences in the re-
activity of Cp and Cp* complexes became evident. The mo-
lecular structure of free 1,2,3,4-tetramethylfulvene [co-crys-
tallised with bis(trimethylsilyl)acetylene] in the solid state
Analytical Data of Compound 3: 1H NMR (300 MHz, [D6]benzene,
297 K): δ = 1.69 (s, 6 H, CH3), 1.84 (s, 6 H, CH3), 5.33 (s, 2 H,
CH2) ppm. 13C NMR (75 MHz, [D6]benzene, 297 K): δ = 9.4
(CH3), 11.2 (CH3), 109.8 (C=CH2), 123.7 (C=CH2), 138.7 (qC),
155.4 (qC) ppm.
Analytical Data of Compound 4: M.p. 125–127 °C (dec. under Ar).
C32H68N4S4Si4Ti2·0.25C6H14: calcd. C 46.94, H 8.62, N 6.35, S
14.53; found C 46.56, H 8.32, N 6.01, S 14.78. IR (ATR, 32 scans,
Scheme 4. Differences in the reactivity of Cp and Cp* ligands.
297 K): ν = 3329 (w), 2951 (m), 2903 (m), 1434 (w), 1376 (w), 1242
˜
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3391

T. Beweries, U. Rosenthal et al.
SHORT COMMUNICATION
(s), 1158 (w), 1058 (w), 933 (m), 826 (s), 746 (m), 657 (m) cm–1. 1H
NMR (300 MHz, [D6]benzene, 297 K): δ = 0.41 (s, 18 H, 2 SiMe3),
0.45 (s, 18 H, 2 SiMe3), 2.01 (s, 30 H, C5Me5), 7.84 (s, 2 H, NH)
ppm. 13C NMR (75 MHz, [D6]benzene, 297 K): δ = 2.4 (SiMe3),
2.6 (SiMe3), 13.1 (C5Me5), 121.6 (C5Me5) ppm. MS (EI): m/z (%)
= 844 (7) [M]+, 677 (24) [M – Cp* – S]+, 542 (5) [M – 2Cp* – S]+,
422 (100) [M/2]+, 390 (28) [M/2 – S]+, 336 (5) [M/2 – NSiMe3]+,
134 (18) [Cp* – H]+.
Acknowledgments
We thank our technical and analytical staff for assistance. Financial
support by the Deutsche Forschungsgemeinschaft (DFG) (RO
1269/8-1) is gratefully acknowledged.
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Analytical Data of Compound 5: IR (ATR, 32 scans, 297 K): ν =
˜
3339 (w), 2952 (m), 2902 (m), 1434 (w), 1377 (w), 1243 (s), 1162
(m), 1055 (m), 984 (m), 936 (m), 893 (s), 826 (s), 747 (s), 661 (m),
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1
600 (m) cm–1. H NMR (300 MHz, [D6]benzene, 297 K): δ = 0.05
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15 H, C5Me5), 6.73 (s, 1 H, NH) ppm. 13C NMR (75 MHz,
[D6]benzene, 297 K): δ = 2.8 (SiMe3), 2.9 (SiMe3), 3.4 (SiMe3), 12.9
(C5Me5), 122.5 (C5Me5) ppm. MS (EI): m/z (%) = 564 (1) [M]+, 360
(30) [Cp*Ti(NHSiMe3)2 + H]+, 206 (5) [S(NSiMe3)2]+, 191 (100)
[S(NSiMe3)2 – Me]+. HRMS (ESI): calcd. for C22H52N4SSi4Ti
564.24637 [M]+; found 564.24786. Because of the small amount of
isolated product, no elemental analysis and no melting point could
be obtained.
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Analytical Data of Compound 6: 1H NMR (300 MHz, [D6]benzene,
1
297 K): H: δ = 1.83 (s, C5Me5) ppm. MS (EI): m/z (%) = 414 (45)
[M]+, 382 (35) [M – S]+, 349 (40) [M – 2S – H]+, 318 (15)
[Cp*2Ti]+, 279 (100) [M – Cp*]+, 247 (18) [M – Cp* – S]+, 214 (29)
[M – Cp* – 2S – H]+. Because of the small amount of isolated
product, no elemental analysis and no melting point could be ob-
tained.
Structure Elucidation
Diffraction data were collected with
a STOE-IPDS II dif-
fractometer using graphite-monochromated Mo-Kα radiation. The
structures were solved by direct methods (SHELXS-97[29]) and re-
fined by full-matrix least-squares techniques on F2 (SHELXL-
97[29]). Diamond was used for graphical representations.[30]
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CCDC-870539 (for 3·BTMSA) and -870538 (for 5) contain the sup-
plementary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Crystallographic Details
3·BTMSA: C18H32Si2, Mr
0.50ϫ0.20ϫ0.15 mm, space group Cmcm, orthorhombic, a =
13.6654(8) Å, 12.8647(7) Å, 11.4138(5) Å,
=
304.62, yellow crystals,
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=
c
=
V =
2006.6(2) Å3, Z = 4, ρcalcd. = 1.008 gcm–3, T = 150 K, μ =
0.169 mm–1, numerical absorption correction (max. and min. trans-
mission: 0.9729 and 0.7980), 13151 reflections collected, 1316 were
independent of symmetry (Rint = 0.0476), of which 1006 were ob-
served [IϾ2σ(I)], R1 [IϾ2σ(I)] = 0.0312, wR2 (all data) = 0.0699,
110 parameters.
ˇ
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Compound 5: C22H52N4SSi4Ti, Mr = 565.00, orange crystals,
0.25ϫ0.20ϫ0.15 mm, space group P21/c, monoclinic,
a =
9.9129(3) Å, b = 36.574(1) Å, c = 9.9692(3) Å, β = 112.233(2)°, V
= 3345.7(2) Å3, Z = 4, ρcalcd. = 1.122 gcm–3, T = 150 K, μ =
0.478 mm–1, 37773 reflections collected, 6291 were independent of
symmetry (Rint = 0.0333), of which 4784 were observed [IϾ2σ(I)],
R1 [IϾ2σ(I)] = 0.0280, wR2 (all data) = 0.0668, 310 parameters.
Selected examples for the activation of the pentamethylcyclo-
pentadienyl ligand: a) K. Kaleta, P. Arndt, T. Beweries, A.
Spannenberg, O. Theilmann, U. Rosenthal, Organometallics
2010, 29, 2604–2609; b) V. Kupfer, U. Thewalt, I. Tisˇlerovaˇ, P.
ˇ
Steˇpnicˇka, R. Gyepes, J. Kubisˇta, M. Horácˇek, K. Mach, J.
Supporting Information (see footnote on the first page of this arti-
cle): NMR spectra.
Organomet. Chem. 2001, 620, 39–50; c) P.-M. Pellny, V. V. Bur-
ˇ
lakov, W. Baumann, A. Spannenberg, M. Horacˇek, P. Steˇp-
3392
www.eurjic.org
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Received: March 9, 2012
Published Online: June 15, 2012
Eur. J. Inorg. Chem. 2012, 3388–3393
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
3393