Insertion of internal alkynes and ethene into permethylated singly tucked-in titanocene

Article abstract of DOI:10.1021/om800691f

The singly tucked-in permethyltitanocene 1 reacts with an excess of internal alkynes to give the 1:1 adducts 3a-c,f-i, arising from insertion of the alkyne triple bond into the titanium-methylene bond. Only the simplest species, 2-butyne, inserted two molecules to give the known compound 2; however, at a 1:1 stoichiometric ratio the 1:1 adduct 3j was also smoothly formed. 1,4-Disubstituted conjugated diynes with CMe3 or SiMe3 substituents reacted in the same way by only one triple bond to give 3d,e, respectively. The dimethylsilylene-bridged dialkynes Me₂Si(C≡CR)₂ (R = SiMe₃, CMe₃) afforded compounds 3k,l with both triple bonds reacting. After insertion of the first triple bond, the second one underwent a rearrangement which resulted in substituent shift and formation of a silacyclobutene ring linked to the titanium atom. Alkynes bearing the bulky substituents CMe₃ and SiMe₃ were unreactive. Among a number of olefins and 1,3-butadiene, only ethene reacted to give cleanly the 1:1 adduct 3m. The structures of the paramagnetic [TFi^III- (η⁵-C₅Me₅)(η⁵: η¹-C₅Me₄(CH₂CR²)}] products 3a-g,k,l were determined by single-crystal X-ray diffraction analysis. These compounds and compounds 3h-j,m, whose crystal structures could not be determined, were chlorinated with PbCl₂ to give the diamagnetic products [Ti^IVCl(η⁵-C₅Me ₅){η⁵:η¹-C₅Me ₄(CH₂CR¹=CR²)}] (4a-j) and the corresponding chlorotitanocene derivatives 4k-m. The solution structures of 4a-m were determined by ¹H and ¹³C NMR spectroscopy, and crystal structures for 4b,e,g,l,m were found by single crystal X-ray diffraction analysis. DFT calculations threw light on the transition-state molecule for the formation of 3j and revealed a steric hindrance to be responsible for preventing the insertion of a second molecule of hex-3-yne, the closest homologue of but-2-yne, to react with 3i, forming a homologue of 2.

Full text of DOI:10.1021/om800691f

5532
Organometallics 2008, 27, 5532–5547
Insertion of Internal Alkynes and Ethene into Permethylated Singly
Tucked-in Titanocene
†
‡
‡
†
†
†
§
ˇ
J. Pinkas, I. Císarˇova´, R. Gyepes, M. Hora´cˇek, J. Kubisˇta, J. Cejka, S. Go´mez-Ruiz,
E. Hey-Hawkins,§ and K. Mach*,†
J. HeyroVsky Institute of Physical Chemistry of Academy of Sciences of the Czech Republic, V.V.i.,
DolejsˇkoVa 3, 182 23 Prague 8, Czech Republic, Department of Inorganic Chemistry, Faculty of Science,
Charles UniVersity, HlaVoVa 2030, 128 40 Prague 2, Czech Republic, and Institut fu¨r Anorganische
Chemie, UniVersita¨t Leipzig, Johannisallee 29, 04103 Leipzig, Germany
ReceiVed July 21, 2008
The singly tucked-in permethyltitanocene 1 reacts with an excess of internal alkynes to give the 1:1
adducts 3a-c,f-i, arising from insertion of the alkyne triple bond into the titanium-methylene bond.
Only the simplest species, 2-butyne, inserted two molecules to give the known compound 2; however,
at a 1:1 stoichiometric ratio the 1:1 adduct 3j was also smoothly formed. 1,4-Disubstituted conjugated
diynes with CMe3 or SiMe3 substituents reacted in the same way by only one triple bond to give 3d,e,
respectively. The dimethylsilylene-bridged dialkynes Me2Si(CtCR)2 (R ) SiMe3, CMe3) afforded
compounds 3k,l with both triple bonds reacting. After insertion of the first triple bond, the second one
underwent a rearrangement which resulted in substituent shift and formation of a silacyclobutene ring
linked to the titanium atom. Alkynes bearing the bulky substituents CMe3 and SiMe3 were unreactive.
Among a number of olefins and 1,3-butadiene, only ethene reacted to give cleanly the 1:1 adduct 3m.
The structures of the paramagnetic [TiIII(η5-C5Me5){η5:η1-C5Me4(CH2CR1dCR2)}] products 3a-g,k,l
were determined by single-crystal X-ray diffraction analysis. These compounds and compounds 3h-j,m,
whose crystal structures could not be determined, were chlorinated with PbCl2 to give the diamagnetic
products [TiIVCl(η5-C5Me5){η5:η1-C5Me4(CH2CR1dCR2)}] (4a-j) and the corresponding chlorotitanocene
derivatives 4k-m. The solution structures of 4a-m were determined by 1H and 13C NMR spectroscopy,
and crystal structures for 4b,e,g,l,m were found by single crystal X-ray diffraction analysis. DFT
calculations threw light on the transition-state molecule for the formation of 3j and revealed a steric
hindrance to be responsible for preventing the insertion of a second molecule of hex-3-yne, the closest
homologue of but-2-yne, to react with 3i, forming a homologue of 2.
Scheme 1
Introduction
Decamethyltitanocene chemistry is well understood, thanks
to the pioneering works by Brintzinger and Bercaw1 and by
Teuben.2 The formation of the paramagnetic singly tucked-in
permethyltitanocene [TiIII{η5:η1-C5Me4(CH2)}(η5-C5Me5)] (1)
was first observed when an equilibrium mixture of decameth-
yltitanocene [Ti(η5-C5Me5)2] with its singly tucked-in (aka η6-
fulvene) hydride [TiH{η6-C5Me4(CH2)}(η5-C5Me5)] was sub-
limedundervacuum.1c Lateron,thermolysisofthedecamethyltitano-
cene monoalkyl compounds [TiIIIR(η5-C5Me5)2] (R ) Me, Et,
Pr, CH2CMe3) appeared to be another clean and convenient
method for obtaining 1 (Scheme 1).2c
110 °C does compound 1 lose another atom of hydrogen to
give the doubly tucked-in compound [Ti{η3:η4-C5Me3(CH2)2}(η5-
C5Me5)], containing one allyl-diene ligand.2a,c Compound 1
is a paramagnetic d1 Ti(III) complex,1,2 as evidenced by its EPR
spectrum (g ) 1.952, ∆H ) 70 G) and the lowest vertical
ionization energy of 5.54 eV in He I and He II photoelectron
spectra (intensity ratio He II/He I ) 1.00) that is typical for a
SOMO d(Ti).3 On the other hand, the electronic absorption
spectrum of 1, showing a single absorption band at λmax 550
nm, is different from the absorption spectra of d1 titanocene
alkyl compounds, which are characterized by two absorptions
in about the same region.2,4 Ultimately, the infrared absorption
band of 1 occurring at 3020 cm-1 is compatible with the
In both cases the liberation of hydrogen or alkane, respec-
tively, is the only process observed. Only at temperatures above
* To whom correspondence should be addressed. E-mail: mach@
jh-inst.cas.cz.
† Academy of Sciences of the Czech Republic.
‡ Charles University.
§ Universita¨t Leipzig.
(1) (a) Bercaw, J. E.; Brintzinger, H. H. J. Am. Chem. Soc. 1971, 93,
2045–2046. (b) Bercaw, J. E.; Marvich, R. H.; Bell, L. G.; Brintzinger,
H. H. J. Am. Chem. Soc. 1972, 94, 1219–1238. (c) Bercaw, J. E. J. Am.
Chem. Soc. 1974, 96, 5087–5095. (d) McDade, C.; Green, J. C.; Bercaw,
J. E. Organometallics 1982, 1, 1629–1634.
(2) (a) Pattiasina, J. W.; Hissink, C. E.; de Boer, J. L.; Meetsma, A.;
Teuben, J. H.; Spek, A. L. J. Am. Chem. Soc. 1985, 107, 7758–7759. (b)
Luinstra, G. A.; ten Cate, L. C.; Heeres, H. J.; Pattiasina, J. W.; Meetsma,
A.; Teuben, J. H. Organometallics 1991, 10, 3227–3237. (c) Luinstra, G. A.;
Teuben, J. H. J. Am. Chem. Soc. 1992, 114, 3361–3367.
(3) Vondra´k, T.; Mach, K.; Varga, V.; Terpstra, A. J. Organomet. Chem.
1992, 425, 27–39.
(4) Lukens, W. W., Jr.; Smith, M. R., III; Andersen, R. A. J. Am. Chem.
Soc. 1996, 118, 1719–1728.
10.1021/om800691f CCC: $40.75
2008 American Chemical Society
Publication on Web 10/09/2008

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5533
Chart 1
In spite of the aforementioned interest in the reactivity of 1,
this compound has not been examined for its reactivity toward
internal alkynes and olefins. We have entered an investigation
of this topic in an effort to find out the mechanism of formation
of the interesting paramagnetic product 2, which formed in high
yield when [TiCl2(η5-C5Me5)2] was reduced with an excess of
magnesium in the presence of excess but-2-yne in tetrahydro-
furan (Scheme 3).9
The formation of 2 could be envisaged as resulting from
insertionoftwomoleculesofbut-2-yneintothetitanium-methylene
bond of 1 transiently generated in the reaction mixture.
Following this suggestion, we have undertaken the investigation
of ability of 1 to undergo insertion reactions with but-2-yne
and a number of other internal alkynes, conjugated and bridged
dialkynes, and simple olefins. The structures of the Ti(III)
insertion products as depending on the nature of the alkyne
presence of an sp2 methylene carbon atom that would fit to the
fulvene formulation of the ligand.1,2,5a Thus, while the un-
equivocal presence of a Ti(III) atom in 1 is compatible with
the η5:η1 bonding of the tucked-in ligand, the infrared absorption
band for a methylene ν(C-H) vibration requires η4:η2 bonding
(Chart 1).
10
substituents, chlorination of the Ti(III) products with PbCl2
The crystal structure of 1 was hampered by an extensive
disorder6 and did not aid in distinguishing between both bonding
modes. Recently, DFT calculations have shown that compound
1 is a d1 complex with strongly mixed d and p orbitals, allowing
for an sp2 character of the exo methylene carbon.7 As we are
aware that the electronic structure of 1 cannot be described with
either of the two canonical structures of Chart 1, the η5:η1
description of 1 will be used throughout the paper to stress that
the high reactivity follows from the Ti(III) valence state.
Reactions of 1 with protonic acids, hydrogen, halogens,
disulfides, methyl halides, nitriles, and 2-methylpyridine were
studied by Pattiasina in his Ph.D thesis and only partly reported
in journals.5 Protonic acids HX such as hydrogen halides,
carboxylic acids, alcohols, and pyrrole split the Ti-methylene
bond to give the Ti(III) decamethyltitanocene derivatives
[TiIIIX(η5-C5Me5)2], while hydrogen under mild conditions
afforded the simple hydride [TiIIIH(η5-C5Me5)2]. Oxidation with
halogens, organic disulfides, or methyl halides gave rise to
Ti(IV) products with the preserved Ti-methylene bond [TiX{η5:
η1-C5Me4(CH2)}(η5-C5Me5)] (X ) Br, I, SPh). Methyl halides
also acted as oxidation agents, yielding a 1:1 mixture of
[TiX{η5:η1-C5Me4(CH2)}(η5-C5Me5)](X)Cl,Br)and[TiMe{η5:
η1-C5Me4(CH2)}(η5-C5Me5)]. tert-Butyl cyanide underwent an
insertion of the CtN bond into the Ti-methylene bond
followed by a proton transfer from the methylene group to the
nitrogen atom, giving an unsaturated titanium amide: e.g.,
[TiIII{η5:η1-C5Me4CHdC(tBu)NH}(η5-C5Me5)].5a,b The most
interesting reaction of 1 was observed for 2-methylpyridine,
whose C-H bond in an ortho position reacted in an opposite
way with respect to protonic acids. The hydrogen atom was
transferred to Ti, the carbon atom was linked to the methylene
carbon, and the nitrogen atom was coordinated to the metal,
thus affording the Ti(III) titanocene hydride stabilized by
intramolecular nitrogen coordination.5c Recently, compound 1
was shown to react with water to form the titanocene hydroxide
[TiIIIOH(η5-C5Me5)2]8a and with the strong Lewis acid B(C6F5)3
to give the paramagnetic zwitterionic complex [(TiIII)+(η5-
C5Me5){η5-C5Me4CH2B-(C6F5)3}] (Scheme 2).8b
in order to obtain the Ti(IV) derivatives accessible to high-
resolution NMR methods, and consideration of the insertion
mechanism on the basis of DFT calculations are reported herein.
Results and Discussion
Compound 1 was obtained from [TiCl2(η5-C5Me5)2] by a
known procedure2 via titanocene chloride and titanocene mono-
methyl and thermolysis in toluene at 110 °C (Scheme 4).
The purple crystalline product was purified by recrystallization
from hexane and gave spectroscopic data1-5 and molecular
parameters that are published elsewhere.6 The solution of 1 in
hexane was reacted with simple internal alkynes, head-to-tail
dimers of pent-1-yne, tert-butylethyne, and (trimethylsilyl)-
ethyne, 1,4-disubstituted 1,3-diynes, and dimethylsilylene-
bridged alkynes, as well as with ethene, but-1-ene, but-2-ene,
tert-butylethene, cyclopentene, and buta-1,3-diene. In all cases
the alkynes or alkenes were used in a 2-10-fold molar excess
with respect to 1. Among the internal alkynes but-2-yne reacted
quickly at room temperature, causing the color of 1 to change
from purple to brownish yellow and finally to the green color
of the known compound 2, containing two but-2-yne molecules
inserted (Scheme 2).9 In contrast, all the other reacting internal
alkynes, including the nearest homologue, hex-3-yne, afforded
the brownish yellow products 3a-i with only one alkyne
molecule inserted. The 1:1 insertion product of but-2-yne, 3j,
was obtained when only 1 molar equiv of the alkyne was
dissolved from the gas phase in a stirred hexane solution of 1
(Scheme 5).
The reactions were accomplished within hours at room
temperature, except for the case of a head-to-tail dimer of
(trimethylsilyl)ethyne, Me3SiCtCC(SiMe3)dCH2, which re-
quired warming to 60 °C for 3 h to yield 3g. The alkynes with
very bulky substituents such as bis(trimethylsilyl)ethyne, (tri-
methylsilyl)tert-butylethyne, and the head-to-tail dimer of tert-
butylethyne, t-BuCtCC-t-BudCH2, did not react even after
heating to 80 °C for 3 days.
The dimethylsilylene-bridged dialkynes Me2Si(CtCSiMe3)2
and Me2Si(CtC-t-Bu)2 reacted smoothly with 1 using both
triple bonds for the insertion combined with a rearrangement
to give the 1-silacyclobut-2-ene moiety (Scheme 6).
(5) (a) Pattiasina, J. W. Ph.D. Thesis, University of Groningen, Gronin-
gen, The Netherlands, 1988; pp 35-77. (b) Ellis, D. D.; Spek, A. L. Acta
Crystallogr. 2000, C56, 558–559. (c) Pattiasina, J. W.; van Bolhuis, F.;
Teuben, J. H. Angew. Chem., Int. Ed. Engl. 1987, 26, 339–340.
(6) Fischer, J. M.; Piers, W. E.; Young, V. G., Jr Organometallics 1996,
15, 2410–2412.
(9) Mach, K.; Gyepes, R.; Kubisˇta, J.; Hora´cˇek, M. Inorg. Chem.
Commun. 2006, 9, 156–159.
(10) (a) Luinstra, G. A.; Teuben, J. H. J. Chem. Soc., Chem. Commun.
1990, 1470–1471. (b) Luinstra, G. A.; Vogelzang, J.; Teuben, J. H.
Organometallics 1992, 11, 2273–2281. (c) Luinstra, G. A.; Teuben, J. H.
J. Am. Chem. Soc. 1992, 114, 3361–3367.
(7) Gyepes, R. Unpublished results.
(8) (a) Hora´cˇek, M.; Gyepes, R.; Kubisˇta, J.; Mach, K. Inorg. Chem.
ˇ
Commun. 2004, 7, 155–159. (b) Varga, V.; Sindela´rˇ, P.; C´ısaˇrova´, I.;
Hora´cˇek, M.; Kubisˇta, J.; Mach, K. Inorg. Chem. Commun. 2005, 8, 222–
226.

5534 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
Scheme 2. Reactivity of 1
Scheme 3
Scheme 5. Preparation of 3a-j
Scheme 4. Synthetic Route to 1
Scheme 6
Rearrangement involving the shift of the SiMe3 group for
3k or t-Bu group for 3l and ring closure apparently had to follow
the insertion of the first triple bond (Scheme 7).
The formation of fused zirconacyclobutene-silacyclobutene11
and titanacyclobutene-silacyclobutene12 complexes (Chart 2,
A) was observed in the reactions of the metallocene at the onset
of their formation with various R2Si(CtCR′)2 derivatives. Also,
spiro dimetallacyclobutene-silacyclobutene complexes sharing
(11) (a) Takahashi, H.; Xi, Z.; Obora, Y.; Suzuki, N. J. Am. Chem. Soc.
1995, 117, 2665–2666. (b) Xi, Z.; Fischer, R.; Hara, R.; Sun, W.-H.; Obora,
Y.; Suzuki, N.; Nakajima, K.; Takahashi, H. J. Am. Chem. Soc. 1997, 119,
12842–12848.
the silicon atom (Chart 2, B) were prepared analogously using
tetraalkynylsilanes.13 Itisofinterestthatthepermethyltitanocene-
ˇ
(12) Hora´cˇek, M.; Bazyakina, N.; Steˇpnicˇka, P.; Gyepes, R.; C´ısaˇrova´,
I.; Bredeau, S.; Meunier, P.; Kubisˇta, J.; Mach, K. J. Organomet. Chem.
2001, 628, 30–38.
(13) Pellny, P.-M.; Peulecke, N.; Burlakov, V. V.; Baumann, W.;
Spannenberg, A.; Rosenthal, U. Organometallics 1996, 15, 1198–1200.

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5535
Scheme 7. Suggested Mechanism of the Formation of 3k,l
hinders coordination of alkynes more bulky than but-2-yne, and
as far as ethene insertion is concerned, the alkyltitanocene
products formed can be higher in energy than 5.15 Although
the insertion reactions into the Ti-C bond are very similar in
both cases, compound 1 affords more coordination space than
5, the methylene group with sp2-hybridized carbon atom is more
easily activated to form a transition complex than the methyl
group in 5, and the intramolecular tether formed is capable of
stabilizing the product more than a titanium-linked pending
alkenyl or alkyl chain.
All the products 3a-m displayed EPR spectra in solution (g
) 1.942-1.962, ∆H ) 10-40 G) and frozen toluene glass,
and electronic absorption spectra showed two absorptions in
the visible region (440-500 and 560-680 nm) (see the
Supporting Information). Both types of spectra resembled the
spectra of TiIII permethyltitanocene alkyl2,4,16 or halide
compounds4,17 with trigonal coordination of the titanium atom.
The crystal structure investigation of 3a-g (see below) found
that such a coordination is only slightly asymmetrical in
compounds 3. All compounds purified by crystallization were
characterized by EI-MS spectra, which mainly showed abundant
molecular ions (M•+) and ions of 1 after elimination of the
alkynes (L) ([M - L]+). The low abundance of M•+ for 3g
(22%) is probably due to a partial thermal dissociation of the
alkyne, whose ions L•+ and [L - Me]+ are also abundant.
Uncertainty about the molecular ion of 3m in standard EI-MS
spectra at IP 70 eV showing [M - 4 H]+ to be the base peak
were solved by measuring with IP of 15 eV which gave M•+
the base peak; however, the abundant loss of hydrogen atoms
from M•+ remained remarkable. The IR spectra gave clear
evidence for the presence of groups such as Ph (3a,c), SiMe3
(3b,c,e,g), t-Bu (3d), CtC (3d,e), and CdCH2 (3f,g); however,
the ν(CdC) vibration that should be present for all the
compounds except 3m was of very low intensity in the range
1590-1510 cm-1 and in some cases was even not discernible
or was hidden under the absorption bands of the Ph group. Due
Chart 2
Scheme 8
1
to paramagnetic broadening and resonance line shifts the H
and 13C NMR spectra were not applicable for resolution of
different substituents in the inserted alkyne. Therefore, the
majority of the products were analyzed by single-crystal X-ray
diffraction, which allowed us to unequivocally identify the
position of substituents in compounds 3a-g, as shown in
Scheme 4, and the structures of 3k,l, as shown in Scheme 5
(see below).
bis(trimethylsilyl)ethyne complex reacted with Me2Si-
(CtCSiMe3)2 to give a different 1-titana-4,4-dimethyl-4-sila-
3,5-bis(trimethylsilyl)cyclohexa-2,5-diene complex (Chart 2,
C)14 and was unreactive to Me2Si(CtC-t-Bu)2.12 On the other
hand, compounds 3d,e, possessing one free triple bond, did not
react with added 1, even at 80 °C, apparently due to some steric
congestion.
Of the olefins only ethene reacted with 1 to give the ocher
product 3m, containing one ethene molecule inserted (Scheme
8). The other olefins and 1,3-butadiene appeared to be nonre-
active, even after heating to 80 °C for 3 days.
The limited reactivity of 1 toward sterically hindered internal
alkynes and olefins becomes understandable after comparing it
with the reactivity of [TiIIIMe(η5-C5Me5)2] (5), the precursor
of 1. The methyl permethyltitanocene 5 did not react with
ethene, even at high pressure and 100 °C, and among internal
alkynes it reacted only with but-2-yne, which inserted one
molecule into the Ti-Me bond to give [TiIIIC(Me)dCMe2(η5-
C5Me5)2].10b This comparison shows that the presence of a
methyl group in the pseudoequatorial plane of 5 apparently
Diamagnetic Chlorinated Compounds 4a-m. Since the
products 3h-j,m did not give crystals suitable for X-ray single-
crystal analysis, these and all other compounds 3 (3a-g,k,l)
were converted to the chlorotitanium(IV) compounds 4a-m by
chlorination with PbCl2 (Scheme 9)10 in order to attempt the
structure resolution by means of 1H and 13C NMR spectroscopy.
All the compounds were red diamagnetic solids which were
somewhat less sensitive to air and humidity than their precursors
3a-m. Their color arose from two absorption bands occurring
in the ranges 395-490 and 475-660 nm (see the Supporting
Information). Their electronic absorption spectra were similar
(15) In our hands reaction of 5 with ethene at 60 °C for 3 days gave a
trace of polyethene and higher olefins and the [TiII(C2H4}(η5-C5Me5)2]
complex20a was the only one isolated from a mixture of products.
(16) (a) De Wolf, J. M.; Blaauw, R.; Meetsma, A.; Teuben, J. H.;
Gyepes, R.; Varga, V.; Mach, K.; Veldman, N.; Spek, A. L. Organometallics
1996, 15, 4977–4983. (b) Pinkas, J.; Lukesˇova´, L.; Gyepes, R.; C´ısaˇrova´,
I.; Lo¨nnecke, P.; Kubisˇta, J.; Hora´cˇek, M.; Mach, K. Organometallics 2007,
26, 3100–3110.
ˇ
(14) Hora´cˇek, M.; Steˇpnicˇka, P.; Gyepes, R.; C´ısaˇrova´, I.; Kubisˇta, J.;
Lukesˇova´, L.; Meunier, P.; Mach, K. Organometallics 2005, 24, 6094–
6103.
(17) Mach, K.; Raynor, J. B. J. Chem. Soc., Dalton Trans. 1992, 683–
688.

5536 Organometallics, Vol. 27, No. 21, 2008
Scheme 9. Chlorination of 3a-m and Structure of the Products 4a-m
Pinkas et al.
Table 1. Selected 1H and 13C NMR Resonances (in ppm) of Compounds 4a-ja
compd
C(21)R1
C(22)R2
1H C(6)H2 (2JHH, Hz)
C(6)
C(21)
C(22)
4a
4b
4c′
4c
4d
4e
4f
4g
4h
4i
Ph
Me
SiMe3
Ph
CMe3
SiMe3
n-Pr
C(SiMe3)d)CH2
Me
Et
Ph
SiMe3
Ph
SiMe3
CtCCMe3
CtCSiMe3
C(dCH2)(CH2)2CH3
SiMe3
Ph
Et
3.14, 3.44 (17.1)
2.81, 2.93 (17.4)
2.91, 3.25 (16.8)
2.89, 3.16 (18.6)
2.86, 3.12 (18.6)
2.78, 3.00 (18.6)
2.94, 3.02 (17.4)
3.07, 3.22 (17.4)
2.92, 3.00 (17.4)
2.76, 2.84 (16.8)
2.75
37.77
40.47
36.32
43.27
37.97
35.31
34.96
40.93
37.88
32.45
36.43
157.35
157.39
163.63
161.03
164.05
166.79
160.93
166.03
157.32
149.25
143.48
204.41
212.91
221.96
215.05
178.45
195.11
208.90
215.54
207.17
212.45
206.98
4j
Me
Me
a Crystallographic atom labeling.
to those of highly methyl-substituted titanocene dichlorides.18
The EI-MS spectra of compounds 4 showed the molecular ions
in low to moderate abundance, except for 4g, whose molecular
ion easily eliminated the alkyne ligand (L) and was not observed.
The [C5Me5TiCl]+ ion was a base peak for all compounds
except 4a, where the [M - C5Me4CH2]+ ion surprisingly
dominated. Less pronounced fragment ions indicated elimination
of HCl, L, or specific groups of alkynes. Infrared spectra
afforded very similar information about the presence of specific
groups, such as the spectra of nonchlorinated precursors.
Decisive information on the structure of compounds 4 was
obtained from their NMR spectra, and this was corroborated
by crystal structures of 4b,e,g,m.
shift was observed in 4m, where the double bond is absent.
Signals for the permethylcyclopentadienyl ring fall into a narrow
1
region in H as well as in 13C spectra (C5Me5, δH 1.62-1.96
ppm, δC 12.66-13.02 ppm; C5Me5, δC 122.96-125.47 ppm),
remaining almost unaffected by the rest of the molecule. The
chemical shifts of TiC(22)dC(21) quaternary carbons (Table
1) in 13C NMR spectra are close to those reported previously
for permethyltitanocene-alkenyl species, the titanium-linked
C(22) being shifted far more downfield.10b,19
The positions of substituents R1 and R2 were assigned on
the basis of 1D NOESY experiments, where irradiation of
C(6)H2 protons enhanced the signal(s) of the substituent at the
C(21) atom, provided it was bearing proton(s) (see the Sup-
porting Information). Thus, determined substituent positions
were consistent with those determined by X-ray diffraction
analysis for compounds 4b,e,g and 3a-g, except for 3c. Unlike
all other cases, only the crystalline 3c was obtained in low yield
(23%), and thus not the pure 3c but the mother liquor was used
for the chlorination. The 1H, 13C, and 29Si NMR spectra of the
chlorination product revealed the presence of two regioisomers
(Table 1), and the 1D NOESY experiment assigned the more
abundant isomer to 4c′ (85%). The irradiation of the high-field
proton (2.91 ppm) of C(6)H2 gave rise to the signal for the SiMe3
group (-0.06 ppm) and the signal of the methyl group in a
1H and 13C NMR spectra of compounds 4 displayed some
general features which are summarized in Table 1. Due to the
stereogenic center at the titanium atom, the protons on C(6)H2
are diastereotopic, giving rise to two doublets in the region
2.7-3.4 ppm with geminal coupling constants 2JHH ) 16.8-18.6
2
Hz. A high value of JHH together with 13C chemical shifs of
C(6) are consistent with sp3 hybridization of the C(6) carbon.
The methyl groups in the tethered C5Me4 ring gave rise to four
signals in both 1H and 13C NMR spectra. Among them, a
relatively large downfield shift of one methyl group signal is
noteworthy. On the basis of gHMBC and 1D NOESY spectra,
this signal is assigned to the methyl group in a position vicinal
to Cipso, close to the Ti-Cl bond (C7 in Figure 5), which induced
its anisotropic deshielding. Although anisotropic deshielding due
to the C(21)-C(22) double bond could also be considered, such
an effect had to be marginal, because a similar methyl downfield
(19) (a) Cohen, S. A.; Bercaw, J. E Organometallics 1985, 4, 1006–
1014. (b) Beckhaus, R.; Sang, J.; Oster, J.; Wagner, T. J. Organomet. Chem.
1994, 484, 179–190. (c) Beckhaus, R.; Strauss, I.; Wagner, T. J. Organomet.
Chem. 1994, 464, 155–161. (d) Beckhaus, R.; Sang, J.; Wagner, T.; Ganter,
B. Organometallics 1996, 15, 1176–1187. (e) Beckhaus, R.; Wagner, T.;
Burlakov, V. V.; Baumann, W.; Peulecke, N.; Spannenberg, A.; Kempe,
R.; Rosenthal, U. Z. Anorg. Allg. Chem. 1998, 624, 129–134. (f) Thomas,
D.; Peulecke, N.; Burlakov, V. V.; Heller, D.; Baumann, W.; Spannenberg,
A.; Kempe, R.; Rosenthal, U.; Beckhaus, R. Z. Anorg. Allg. Chem. 1998,
624, 919–924.
(18) (a) Finch, W. C.; Anslyn, E. V.; Grubbs, R. H. J. Am. Chem. Soc.
1988, 110, 2406–2413. (b) Hora´cˇek, M.; Gyepes, R.; C´ısaˇrova´, I.; Pola´sˇek,
M.; Varga, V.; Mach, K. Collect. Czech. Chem. Commun. 1996, 61, 1307–
1320.

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5537
Figure 1. PLATON30 drawing of 3c at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
Figure 2. PLATON30 drawing of 3e at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
position vicinal to Cipso, remote from the Ti-Cl bond (C10 in
Figure 5) (1.85 ppm), in addition to the second signal (3.25
ppm) of C(6)H2. Subsequent irradiation of the downfield proton
(3.25 ppm) of C(6)H2 gave rise to the signals of the SiMe3 group
(-0.06 ppm), the permethylcyclopentadienyl ligand (1.62 ppm),
and the methyl group in a position vicinal to Cipso, close to the
Ti-Cl bond (C7 in Figure 5) (2.62 ppm), in addition to the
signal of C(6)H2 at 2.91 ppm. The NMR assessment of 4c (15%)
and 4c′ (85%) allowed us to determine the abundance of the
formed regioisomers 3c and 3c′. Assuming that 3c (23%) was
removed by crystallization before the chlorination, the crude
insertion product should consist of 3c (35%) and 3c′ (65%).
The 1H and 13C NMR spectra revealed the presence of alkynyl
groups on C(22) in 4d,e displaying resonances typical for
quaternary acetylenic carbons (89.58 and 113.02 ppm for 4d;
106.69 and 115.60 ppm for 4e). The presence of a dCH2 group
in 4f,g was also unequivocally detected (4f, δH 4.35, 4.77 ppm,
δC 106.31 ppm; 4g, δH 5.39, 5.75, δC 127.08), showing the
signal of the upfield shifted methylene proton to be significantly
broadened in the both complexes. For 4g, the signal of C5Me5
at δC 124.14 ppm, C(22) at δC 215.54 ppm, and the signal at
-14.13 ppm in the 29Si NMR spectrum were also broadened.
Complexes 4k,l contained a silacyclobutene ring taking part
in their tether chains. Their quaternary carbon atoms directly
linked to titanium were shifted highly downfield, δC 264.56 ppm
for 4k and δC 240.69 ppm for 4l, whereas the other sp2
quaternary carbon atoms resonated as expected.19
Figure 3. PLATON30 drawing of 3f at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
The trimethylene chain in 4m displayed three resonances at
δC 25.64, 44.67, and 80.58 ppm. The last one falls into the range
of δC for an sp3 carbon linked to the titanium atom.20 The proton
signals of the methylene groups are rather complicated, due to
the presence of a stereogenic titanium center. The highly upfield
shifted signal at -0.42 ppm was attributed to the hydrogen atom
of the TiCH2 group, which is directed toward the Ti-Cl bond.
Crystal Structures of 3a-g. The crystal structures of 3a-g
are generally uniform, resembling the trigonal coordination of
the central atom known for TiIII permethyltitanocene monosub-
stituted complexes. The selected PLATON drawings of com-
pounds 3c (Figure 1), 3e (Figure 2), 3f (Figure 3), and 3g (Figure
4) represent various types of alkyne products; however, the
Figure 4. PLATON30 drawing of 3g at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
(20) (a) Cohen, S. A.; Auburn, P.; Bercaw, J. E. J. Am. Chem. Soc.
ˇ
1983, 105, 1136–1143. (b) Lukesˇova´, L.; Hora´cˇek, M.; Steˇpnicˇka, P.;
Gyepes, R.; C´ısarˇova´, I.; Kubisˇta, J.; Mach, K. J. Organomet. Chem. 2004,
ˇ
689, 1919–1929. (c) Hora´cˇek, M.; Steˇpnicˇka, P.; Kubisˇta, J.; C´ısarˇova´, I.;
geometry of the inserted disubstituted alkenylene moiety is only
moderately affected by the substituents R1 and R2 at the C(21)
and C(22) carbon atoms. The substituents were found in the
Petrusova´, L.; Mach, K. J. Organomet. Chem. 2003, 667, 154–166. (d)
ˇ
Hora´cˇek, M.; Steˇpnicˇka, P.; Gyepes, R.; C´ısarˇova´, I.; Tisˇlerova´, I.; Zema´nek,
J.; Kubisˇta, J.; Mach, K. Chem. Eur. J. 2000, 6, 2397–2408.

5538 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
allowing for a moderate variation in the Cg(1)-Ti-Cg(2),
Cg(1)-Ti-C(22), Ti-C(22)-C(21), and C(22)-C(21)-C(6)
angles.
The tether bond Ti-C(22) is inclined to the Cg(1) cyclo-
pentadienyl ring, as the Cg(1)-Ti-C(22) angle is ca. 12-15°
smaller than Cg(2)-Ti-C(22). The substituted Ti-C-
(R1)dC(R2)-- moiety in 3a-g is only slightly more bent than
the Ti-CHdCH2 group in Cp*2Ti(L)CH)CH2 (L ) F, OR)
compounds.19b,c The geometry of the tether is influenced by
their substituents, however. At least, the Ti-C(22)-C(21) angle
is markedly larger than the C(22)-C(21)-C(6) angle when the
carbon atom C(22) is carrying a trimethylsilyl group (3b,c,g).The
torsion angles at the double bond (τ
) Ti-C(22)-
Figure 5. PLATON30 drawing of 4b at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
C(21)-C(6) and ω involving the substituent atoms (C or Si) at
C(22)-C(21)) indicate a nearly planar arrangement for 3a,e;
however, in other compounds these angles approach up to 30°
(see Table 2). This deviation from double-bond planarity
together with a somewhat elongated CdC bond is due to the
vicinity of the transition metal.
Crystal Structures of 4b,e,g,m. PLATON drawings of
4b,e,g,m are shown in Figures 5-8, respectively, and their
common geometric parameters are given in Table 3. The
parameters for 4b,e,g can be compared with the corresponding
parameters for their Ti(III) precursors (cf. Table 2). The chlorine
atom occupies roughly the equatorial position, as indicated by
the mutually close magnitudes of the Cg(1)-Ti-Cl and
Cg(2)-Ti-Clangles.TheTi-Clbondlengths2.3267(5)-2.3442(6)
Å are slightly shorter than the bonds in [TiCl2(η5-C5Me5)2]
(average 2.349(1) Å),21a [TiCl2(η5-C5Me4-t-Bu)2] (2.3666(4)
Å),21b and [TiCl2(η5-C5Me4SiMe3)2] (2.365(1) Å).18b The
chlorine addition brought about a slight increase in all bond
lengths, which were influenced by a larger coordination number
of the metal.
Figure 6. PLATON30 drawing of 4e at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
The pseudotetrahedral coordination of the titanium atom
accounts for the smaller Cg(1)-Ti-Cg(2) angles and a smaller
difference in the Cg(1)-Ti-C(22) and Cg(2)-Ti-C(22) angles.
The tether geometry is changed only slightly from the tether
geometry for their precursors. Compound 4m differs from the
above structures by the tether being composed of only sp3 carbon
atoms. Due to this, the Ti-C(22) is discernibly shorter, the bond
lengths C(21)-C(22) and C(21)-C(6) are virtually equal, and
the valence angles at C(21) and C(22) are close to tetrahedral.
Crystal Structures of 3k,l and 4l. The unit cells of 3k and
3l contained two independent molecules whose geometric
parameters differed only slightly; therefore the geometry of
molecules 1 will be discussed only. The PLATON drawing for
molecule 1 of 3l is shown in Figure 9 and that for 4l in Figure
10.
The selected geometric parameters for 3k (molecule 1), 3l
(molecule 1) (molecules 1 are labeled using prefix 1), and 4l
are given in Table 4. As for 3a-g the Ti-Cg(11) distances in
3k,l are shorter than the Ti-Cg(12) distances and the
Cg(11)-Ti-C(123) angles are smaller than those involving
Cg(12). The tether between the cyclopentadienyl ring and the
titanium atom is longer by one carbon. An additional C-C bond
(C(123)-C(122)) forms a saturated side of the formed silacy-
clobutene moiety. Its geometry is similar to those involved in
the fused titanacyclobutene-silacyclobutene moieties:12,13 the
angle at the Si atom is about 75°, whereas that at the opposite
carbonatomC(123)isabove100°.ThedoublebondC(123)-C(124)
forming the silacyclobutene cycle (1.386(2) Å for 3k and
1.376(3) Å for 3l) is markedly longer than the analogous double
bond in titanacyclobutene compounds.19b,c On the other hand,
the exocyclic double bond C(121)-C(122) is shorter than the
Figure 7. PLATON30 drawing of 4g at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
positions indicated in Scheme 5. The geometric parameters
gathered in Table 2 show that the tethered cyclopentadienyl
ligand is more tightly bound to the titanium atom than the intact
ligand (Ti-Cg(1) ) 2.033(2)-2.0561(15) Å versus Ti-Cg(2)
) 2.062(3)-2.0885(15) Å), confirming the presence of the
double bond (C(21)sC(22) ) 1.354(6)-1.369(7) Å) and its
linking to the titanium atom (Ti-C(22) ) 2.201(5)-2.280(2)
Å)andthemethylenecarbon(C(6)-C(21))1.497(3)-1.5338(19)
Å). The angles in the tethered alkenylene system are versatile,

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5539
Table 2. Important Common Bond Lengths (Å) and Valence and Dihedral Angles (deg) for 3a-g
3a
3b
3c
3d
3e
3f
3g
Bond Lengths (Å)
Ti-Cg(1)a
Ti-Cg(2)a
Ti-C(22)
C(21)-C(22)
C(6)-C21)
2.0499(10)
2.0777(10)
2.280(2)
1.355(3)
1.497(3)
2.033(2)
2.0782(18)
2.246(3)
1.355(5)
1.530(5)
2.0471(7)
2.0731(7)
2.2512(15)
1.364(2)
2.037(2)
2.062(3)
2.201(5)
1.369(7)
1.518(7)
2.0436(9)
2.0672(9)
2.2604(18)
1.354(6)
2.0561(15)
2.0885(15)
2.265(3)
1.361(4)
1.500(5)
2.0359(7)
2.0801(7)
2.2423(14)
1.3627(19)
1.5338(19)
1.529(2)
1.508(6)
Valence Angles (deg)
Cg(1)-Ti-Cg(2)
Cg(1)-Ti-C(22)
Cg(2)-Ti-C(22)
Ti-C(22)-C(21
C(22)-C(21)-C(6)
139.90(4)
103.17(6)
116.91(6)
117.83(15)
120.35(19)
141.81(8)
101.40(12)
116.61(12)
109.5(2)
141.83(3)
102.40(4)
114.68(4)
108.34(10)
122.12(13)
145.86(11)
142.03(3)
103.61(5)
114.36(5)
120.84(12)
117.61(16)
140.32(6)
103.62(9)
115.89(9)
116.6(2)
119.7(3)
141.73(3)
102.07(4)
115.37(4)
108.43(10)
122.20(12)
100.39(14)
113.34(14)
117.0(3)
121.8(3)
116.7(4)
Dihedral Angles (deg)
ꢀb
τc
35.91(12)
0.1(3)
4.5(3)
33.70(19)
28.2(4)
28.3(4)
33.22(5)
31.97(16)
34.89(7)
-3.4(2)
-2.1(2)
36.24(9)
14.4(4)
11.0(5)
33.57(4)
25.23(16)
30.03(19)
-24.57(17)
-29.5(2)
20.0(6)
13.2(6)
ωd
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 Dihedral angle Ti-C(22)-C(21)-C(6). d Dihedral angle involving C(21) and C(22) and attached atoms (C or Si) of their
substituents.
Table 3. Selected Bond Lengths (Å) and Bond Angles (deg) for
4b,e,g,m
4b
4e
4g
4m
Bond Lengths (A)
Ti-Cg(1)a
Ti-Cg(2)a
Ti-Cl
Ti-C(22)
C(21)-C(22)
C(6)-C(21)
2.1080(8)
2.1334(8)
2.3267(5)
2.1005(9)
2.1145(9)
2.3354(6)
2.1155(9)
2.1055(19)
2.1435(10) 2.124(2)
2.3442(6)
2.257(2)
1.366(3)
1.520(3)
2.3573(12)
2.200(5)
1.526(8)
1.524(8)
2.2466(16) 2.212(2)
1.356(2)
1.521(2)
1.358(3)
1.520(3)
Bond Angles (deg)
Cg(1)-Ti-Cg(2)
Cg(1)-Ti-C(22)
Cg(2)-Ti-C(22)
Cg(1)-Ti-Cl
135.94(3)
138.54(4)
98.35(6)
104.08(6)
105.68(3)
106.53(3)
95.01(6)
134.88(4)
101.36(6)
106.39(6)
104.19(3)
106.02(4)
98.47(5)
138.95((8)
99.08(14)
105.53(14)
106.19(6)
105.69(6)
91.02(15)
100.28(5)
107.37(5)
104.60(2)
105.74(2)
96.13(5)
Cg(2)-Ti-Cl
Cl-Ti-C(22)
Ti-C(22)-C(21)
116.77(12) 121.38(15) 116.26(14) 112.9(3)
C(22)-C(21)-C(6) 120.24(15) 116.43(17) 120.79(18) 109.0(4)
Figure 8. PLATON30 drawing of 4m at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
Dihedral Angles (deg)
ꢀb
τc
43.66(7)
6.3(2)
13.9(3)
40.81(10)
10.2(2)
8.9(3)
44.19(7)
11.9(2)
23.3(3)
41.64(12)
ωd
double bonds in 3a-g, due to its remoteness from the metal.
In 4l, addition of the chlorine atom at a roughly equatorial
position resulted in a slight prolongation of all bonds which
were influenced by an increased coordination number of the
metal. The geometry of the silacyclobutene ring and the overall
geometry of the tether moiety were changed rather negligibly,
however.
Insertion Mechanism and Steric Limitations. The transition
state for the reaction of 1 with one molecule of but-2-yne was
determined by DFT calculations. The initial solid-state geometry
of 1 with one but-2-yne molecule added in the equatorial plane
(the plane perpendicular to the Cg(1)-Ti-Cg(2) angle and
bisecting it) from the open shell side was optimized to a first-
order saddle point. The transition-state geometry (Figure 11) is
characterized by the triple bond prolongation to 1.39 Å and its
π-mode binding to the titanium atom resembling the well-known
structure of titanocene-bis(trimethylsilyl)ethyne complexes.22
The internal carbon atom of the arising tether is weakly
bonded to the methylene carbon atom (C(1)-C(2) ) 1.62 Å),
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 Dihedral angle
Ti-C(22)-C(21)-C(6). d Dihedral angle involving C(21) and C(22) and
attached atoms (C or Si) of their substituents.
and its bond to the titanium atom is longer than that of the
terminal tether atom (Ti-C(2) ) 2.36 Å versus Ti-C(3) )
2.17 Å). The imaginary frequency devised for the transition state
breaks the Ti-C(2) bond and shortens the C(1)-C(2) and the
C(2)-C(3) bonds, as expected for 3j (see the corresponding
bond lengths for 3a-g in Table 2).
Theoretical investigations have also showed that the molecule
constructed by insertion of two molecules of hex-3-yne into 1
(2a) is stable and its geometry is very similar to that of 2 (see
the Supporting Information). Since the above experiments
proved that compound 2 is formed via the intermediate
compound 3j and since compound 3i was the sole product
obtained with a large excess of hex-3-yne, it has to be assumed
that it is steric congestion due to the presence of substituents
larger than the methyl that does not allow an effective
coordination of the second molecule of the respective alkyne
to 3a-i in a step which should precede its insertion. The
reluctance of 3m to insert another molecule of ethene is due to
the lower reactivity of ethene compared to that of but-2-yne
(21) (a) McKenzie, T. C.; Sanner, R. D.; Bercaw, J. E. J. Organomet.
Chem. 1975, 102, 457–466. (b) Lukesˇova´, L.; Gyepes, R.; Pinkas, J.;
ˇ
Hora´cˇek, M.; Kubisˇta, J.; Cejka, J.; Mach, K. Collect. Czech. Chem.
Commun. 2005, 70, 1589–1603.
(22) Rosenthal, U.; Burlakov, V. V.; Arndt, P.; Baumann, W.; Span-
nenberg, A Organometallics 2003, 22, 884–900.

5540 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
Table 4. Selected Bond Lengths (Å) and Bond Angles (deg) for 3ka,
3la, and 4lb
3k
3l
4l
Bond Lengths (A)
Ti(1)-Cg(11)c
Ti(1)--Cg(12)c
Ti(1)-C(123)
C(122)-C(123)
C(123)-C(124)
C(124)-Si(11)
C(122)-Si(11)
C(121)-C(122)
C(121)-C(16)
2.0413(9) 2.0463(10) 2.1108(7)
2.0648(10) 2.0847(11) 2.1539(6)
2.1660(17) 2.180(2)
1.523(2)
1.386(2)
1.856(2)
1.8932(18) 1.884(2)
1.348(3)
1.537(3)
2.2012(13)
1.5281(18)
1.3876(18)
1.8473(15)
1.8757(14)
1.3487(19)
1.522(2)
1.518(3)
1.376(3)
1.849(2)
1.345(3)
1.531(3)
Bond Angles (deg)
Cg(11)-Ti(1)-Cg(12)
Cg(11)-Ti(1)-C(123)
Cg(12)-Ti(1)-C(123)
Ti(1)-C(123)-C(122)
Ti(1)-C(123)-C(124)
C(122)-C(123)-C(124)
C(123)-C(124)-Si(11)
C(123)-C(122)-Si(11)
C(122)-Si(11)-C(124)
C(16)-C(121)-C(122)
C(122)-C(121)-C(126)
145.85((4) 143.17(4) 137.50(2)
103.34(5) 102.24(6) 98.07(4)
109.36(5) 110.37(6) 106.17(4)
114.38(11) 118.49(13) 119.40(9)
141.61(14) 138.42(16) 137.89(10)
103.92(15) 103.05(17) 102.68(11)
92.66(12) 93.46(14) 93.41(9)
87.02(11) 87.69(12) 87.90(8)
Figure 9. PLATON30 drawing of 3l at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
75.37(8)
74.80(9)
75.46(6)
125.92(17) 124.40(18) 124.42(12)
120.05(14) 122.91(18) 122.47(13)
Dihedral Angles (deg)
C(122)-C(123)-C(124)-C(125) 166.47(17) 169.9(2)
171.80(17)
25.0(2)
C(126)-C(121)-C(122)-Si(11) 29.7(3)
28.4(3)
ꢀd
τe
33.26(10) 35.89(11) 45.03(4)
28.45(11) 28.95(12) 31.53(4)
13.48(14) 11.26(15) 13.68(9)
ωf
a Two independent molecules in the unit cell differ slightly. The data
for molecule 1 are listed only. Atoms for molecule 1 are numbered with
prefix 1 (otherwise equally as for 4l). b Additional data for 4l: Ti-Cl )
2.3429(4) Å; Cl-Ti-C(23) ) 103.92(4)°; Cg(1)-Ti-Cl ) 104.06(2)°;
Cg(2)-Ti-Cl ) 103.27(2)°. c Cg(11) and Cg(12) are centroids of the
C(11-15) and C(111-115) cyclopentadienyl rings, respectively.
d Dihedral angle between the least-squares planes of cyclopentadienyl
rings. e Dihedral angle between the least-squares planes of
cyclopentadienyl ring C(1-5) and the silacyclobutene ring. f Dihedral
angle between the least-squares planes of cyclopentadienyl ring
C(111-115) and the silacyclobutene ring.
Figure 10. PLATON30 drawing of 4l at the 30% probability level
with the atom-labeling scheme. Hydrogen atoms are omitted for
clarity.
and to the better stability of the propane-1,3-diyl tether compared
to that of the longer pentane-1,5-diyl tether.
Conclusions
The singly tucked-in permethyltitanocene 1 rapidly inserts
internal alkynes with not extremely bulky substituents into its
highly reactive titanium-methylene bond to give the new class
of thermally robust Ti(III) propenyl-tethered derivatives 3a-j.
Among them, only 3j is able to insert another molecule of an
alkyne, but-2-yne, to give the pentadienyl-tethered compound
2. The reluctance of 3a-i to insert the respective alkyne is due
to insufficient coordination space at the titanium atom. The DFT
calculation identified the transition state for formation of 3j as
arising from π-coordination of the alkyne in a pseudoequatorial
plane. The mode of insertion of unsymmetrical alkynes is
determined by the polarity of the Tiδ+-Cδ-R1d bond as well
as by steric congestion, and the high regioselectivity of the
insertion is rather surprising. Thus, the electron-withdrawing
groups preferably reside on this carbon (Ph, alkynyl, SiMe3),
whereas electron-donating alkyl groups (Me, t-Bu) occupy the
other, more positive carbon atom of the double bond. In this
respect, the electronic effects of the phenyl and trimethylsilyl
groups should be similar, because only in the compound derived
from phenyl(trimethylsilyl)ethyne were both isomers (3c, 3c′)
established in comparable abundance. Nonetheless, steric de-
Figure 11. Transition state for the formation of 3j. Calculated
distances (Å): Ti-C(2) ) 2.36, Ti-C(3) ) 2.17, C(1)-C(2) )
1.62, C(2)-C(3) ) 1.39, C(2)-C(5) ) 1.53, C(3)-C(4) ) 1.50.
mands can also play an important role, as exemplified by the
reluctance of 1 to react with sterically hindered alkynes or with
the free triple bond of 3d,e. The dialkynyldimethylsilanes react
with 1 by both triple bonds; however, this occurs with the
formation of a silacyclobutene moiety that has been encountered
in similar titanocene and zirconocene systems.11-13 Among a
number of olefins only ethene underwent the insertion to give
the propane-1,3-diyl tethered permethyltitanocene 3m. An easy
and nearly quantitative chlorination of paramagnetic compounds
3 affords diamagnetic compounds 4, which are suitable for
structure determination with NMR methods. Both series of

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5541
Table 5. Crystallographic Data and Data Collection and Structure Refinement Details for 3a-g,k,l and 4b,e,g,l,m
3a
3b
3c
3d
3e
formula
mol wt
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
(deg)
C34H39Ti
495.55
C26H41SiTi
429.58
C31H43SiTi
491.64
C32H47Ti
479.60
C30H47Si2Ti
511.76
monoclinic
P21/c (No. 14)
10.0271(3)
13.3244(4)
20.5151(5)
90
95.788(3)
90
2726.95(13)
4
1.207
0.334
reddish brown
0.4 × 0.2 × 0.1
180(2)
monoclinic
C2/c (No. 15)
34.8395(14)
8.5922(3)
20.4083(8)
90
125.7742(15)
90
4956.5(3)
8
triclinic
triclinic
monoclinic
P21/c (No. 14)
13.7810(2)
12.3880(2)
18.3740(4)
90
105.5660(10)
90
3021.74(9)
4
j
j
P1 (No. 2)
P1 (No. 2)
8.6571(2)
14.2383(3)
14.2383(3)
99.8037(10)
90.9041(13)
103.7740(12)
1359.02(6)
2
8.8960(4)
15.2670(8)
15.2670(8)
92.443(2)
105.854(3)
111.242(3)
1465.42(12)
2
1.087
0.308
reddish brown
0.18 × 0.50 × 0.75
293(2)
γ (deg)
V (Å3)
Z
Dcalcd (g cm-3
)
1.151
0.403
brown
1.201
0.376
brown
1.125
0.378
red
µ (mm-1
)
color
cryst size (mm3)
0.5 × 0.4 × 0.3
0.23 × 0.45 × 0.58
0.2 × 0.2 × 0.5
T (K)
150(2)
150(2)
150(2)
θ
min, θmax (deg)
2.55, 27.10
-12 to +12
-17 to +17
-26 to +26
23 547
2.00, 26.02
-42 to +42
-10 to +10
-25 to +25
28 513
1.5, 27.6
-11 to +11
-14 to +14
-18 to +18
22 685
3.10, 25.12
-10 to +10
-14 to +14
-18 to +18
16 077
1.5, 27.5
-17 to +17
-16 to +16
-23 to +23
51 240
range of h
range of k
range of l
no. of rflns collected
no. of unique rflns
F(000)
6011
1060
4861
1864
6236
530
5129
522
6919
1108
no. of params
472
9.25, 8.97
0.964
4.44, 7.60
0.22, -0.30
275
5.35, 13.88
1.047
4.96, 13.54
0.957, -0.566
310
4.36, 9.31
1.02
3.53, 8.82
0.36, -0.29
328
8.61, 24.97
1.122
7.56, 24.22
0.366, -0.353
321
5.58, 10.18
1.056
3.86, 9.32
0.25, -0.353
R(F), Rw(F2) (all data) (%)
GOF(F2) (all data)
R(F), Rw(F2) (I > 2σ(I))
∆F (e Å´-3
)
3f
3g
3k
3l
formula
mol wt
C30H45Ti
453.56
C30H49Si2Ti
513.77
C32H53Si3Ti
569.91
C34H53SiTi
537.75
cryst syst
space group
a (Å)
b (Å)
c (Å)
orthorhombic
Pbca (No. 61)
14.9530(7)
17.0466(4)
21.4640(9)
90
90
90
5471.1(4)
8
1.101
triclinic
P1 (No. 2)
orthorhombic
Pca21 (No. 29)
19.3155(2)
12.0150(3)
28.9179(5)
90
90
90
6711.1(2)
8
1.128
monoclinic
P21/c (No. 14)
29.3847(2)
11.9628(1)
18.7935(3)
90
108.4411(12)
90
6267.11(12)
8
j
9.0306(2)
11.9583(3)
14.7172(2)
89.3701(13)
82.0966(13)
71.3318(10)
1490.48(5)
2
R (deg)
(deg)
γ (deg)
V (Å3)
Z
Dcalcd (g cm-3
)
1.145
0.383
red
1.140
0.331
green
µ (mm-1
)
0.327
0.380
green
color
dark red
0.9 × 0.5 × 0.1
293(2)
cryst size (mm3)
0.5 × 0.5 × 0.35
0.5 × 0.5 × 0.4
0.4 × 0.3 × 0.2
T (K)
150(2)
150(2)
150(2)
θ
min, θmax (deg)
3.12, 27.48
-19 to +19
-22 to +22
-27 to +27
37 907
1.40, 27.46
-11 to +11
-15 to +15
-18 to +19
28 408
1.41, 27.50
-24 to +25
-15 to +15
-37 to +37
58 772
1.46, 27.58
-38 to +38
-15 to +15
-24 to +24
127 410
range of h
range of k
range of l
no. of rflns collected
no. of unique rflns
F(000)
6260
1976
6803
558
14 750
2472
14 392
2344
no. of params
291
15.40, 18.83
1.022
6.74, 15.21
0.445, -0.434
321
4.0, 8.74
1.025
3.31, 8.26
0.322, -0.338
700
3.48, 7.85
1.037
3.07, 7.52
0.251, -0.294
675
6.39, 12.47
1.063
4.86, 11.69
0.718, -0.367
R(F), Rw(F2) (all data) (%)
GOF(F2) (all data)
R(F), Rw(F2) (I > 2σ(I))
∆F (e Å´-3
)
4b
4e
4g
4l
4m
formula
mol wt
cryst syst
space group
a (Å)
b (Å)
c (Å)
R (deg)
(deg)
C26H41ClSiTi
465.03
C30H47ClSi2Ti
547.21
C30H49ClSi2Ti
549.22
C34H53ClSiTi
573.20
C22H33ClTi
380.83
orthorhombic
P212121 (No. 19)
10.4972(1)
11.3834(2)
20.9230(3)
90
monoclinic
C2/c (No. 15)
22.1646(8)
18.0672(7)
15.7913(3)
90
97.899(2)
90
6263.7(4)
8
triclinic
monoclinic
C2/c (No. 15)
31.7739(5)
20.4057(3)
11.1870(1)
90
109.5524(9)
90
6835.04(16)
8
tetragonal
j
j
P1 (No. 2)
P4 (No. 81)
8.6384(3)
11.4893(2)
15.6002(4)
78.9559(16)
77.8493(14)
86.9128(16)
1485.44(7)
2
15.3776(4)
15.3776(4)
8.3838(2)
90
90
90
1982.52(9)
4
1.276
90
90
γ (deg)
V (Å3)
Z
2500.17(6)
4
1.235
Dcalcd (g cm-3
)
1.161
1.228
1.114

5542 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
Table 5. Continued
4e
4b
4g
4l
4m
µ (mm-1
)
0.508
0.383
dark red
0.476
brown
0.383
brown
0.567
brown
color
dark red
0.5 × 0.5 × 0.3
150(2)
cryst size (mm3)
T (K)
0.5 × 0.35 × 0.2
0.5 × 0.45 × 0.25
0.6 × 0.5 × 0.25
0.5 × 0.5 × 0.3
150(2)
150(2)
150(2)
150(2)
θ
min, θmax (deg)
1.95, 27.48
-13 to +13
-14 to +14
-27 to +27
36 612
1.87, 26.03
-27 to +27
-22 to +19
-19 to +19
30 206
2.05, 27.47
-11 to +11
-14 to +14
-20 to +20
26 429
1.36, 27.50
-41 to +41
-26 to +26
-14 to +14
64 166
1.87, 27.13
-19 to +19
-19 to +19
-10 to +10
31 026
range of h
range of k
range of l
no. of rflns collected
no. of unique rflns
F(000)
5736
1000
6113
2352
6779
592
7856
2480
4359
816
no. of params
283
3.00, 7.25
1.051
2.78, 7.10
0.251, -0.228
330
5.13, 10.64
1.062
3.88, 9.52
0.491, -0.369
338
6.13, 10.40
1.022
4.10, 9.37
0.345, -0.293
359
4.02, 9.03
1.051
3.20, 8.58
0.347, -0.276
227
5.18, 15.17
1.120
5.10, 15.10
1.019, -0.404
R(F), Rw(F2) (all data) (%)
GOF(F2) (all data)
R(F), Rw(F2) (I > 2σ(I))
∆F (e Å´-3
)
vacuum systems. The solid diynes t-BuCtCCtC-t-Bu and
Me3SiCtCCtCSiMe3 (Aldrich) were degassed under vacuum. The
diynes Me2Si(CtC-t-Bu)2 and Me2Si(CtCSiMe3)2 were prepared
and used as reported elsewhere.12 Head-to-tail dimers of 1-pentyne,
(trimethylsilyl)ethyne, and tert-butylethyne (RCtCC(R)dCH2; R
) Pr, SiMe3, t-Bu) were obtained using Ti catalysts.24 Buta-1,3-
diene of purity for Ti-catalyzed cyclotrimerization25 and ethene
purified by reaction with [Ti(η5-C5Me4SiMe3)2]26 were used.
[TiCl2(η5-C5Me5)2] and magnesium (turnings for Grignard reaction)
were purchased from Aldrich and used as such after degassing.
Methyllithium (LiMe) 1.6 M in diethyl ether (Aldrich) was degassed
and distributed in sealed ampules. The singly tucked-in permeth-
yltitanocene [TiIII{η5:η1-C5Me4(CH2)}(η5-C5Me5)] (1) was prepared
from [TiCl2(η5-C5Me5)2] via [TiCl(η5-C5Me5)2] and [TiMe(η5-
C5Me5)2] by thermolysis of the latter at 110 °C for 3 h (see the
Supporting Information).
Preparation of 2 from 1. Compound 1 (0.50 g, 1.57 mmol)
was dissolved in hexane (20 mL) and the solution mixed with but-
2-yne (1.0 mL, 8.0 mmol) and stirred at room temperature. The
initial purple color of 1 turned rapidly to ocher-brown and finally
to khaki-green. After 3 h all volatiles were evaporated under
vacuum, and a dark green residue was extracted with hexane (10
mL). The solution was concentrated to ca. 5 mL and left to
crystallize in a freezer (-28 °C). Green crystalline product was
separated and dried under vacuum. Yield: 0.57 g (86%). The product
gave EI-MS, IR, EPR and UV-vis spectra identical with those
reported for 2.9
Preparation of Compounds 3a-g. Compound 1 (0.50 g, 1.57
mmol) was dissolved in hexane (20 mL), and the solution was
mixed with the hexane solution of an internal alkyne (2-6 mmol
in 15 mL). The solution was stirred at room temperature until the
color changed to brown (1-3 h), and the stirring was continued
for another such period (for 3g see below). All volatiles were
evaporated under vacuum, and the residue was dissolved in a
minimum amount of hexane. For nonvolatile alkynes excess alkyne
was removed from the product by fractional crystallization at low
temperature (3a,c-g). Compounds 3a-g were obtained pure by
recrystallization from hexane.
compounds have a high potential for further application in
organometallic synthesis and catalysis: e.g., via formation of
zwitterionic complexes with strong Lewis acids.
Experimental Section
General Considerations. Synthesis of 1 and its reactions with
internal acetylenes and olefins were carried out under vacuum on
a vacuum line in sealed all-glass devices equipped with breakable
seals or under an argon atmosphere. 1H (300 MHz), 13C (75 MHz),
and 29Si (59.6 MHz) NMR spectra were recorded on a Varian
Mercury 300 spectrometer in C6D6 solutions at 25 °C. Chemical
shifts (δ/ppm) are given relative to the residual solvent signal (δH
7.15) and to the solvent resonance (δC 128.0). The δSi values are
related to tetramethylsilane. The NOESY 1D experiment was
performed using a mixing time of 500 ms. EI-MS spectra were
obtained on a VG-7070E mass spectrometer at 70 eV. Crystalline
samples in sealed capillaries were opened and inserted into the direct
inlet under argon. The spectra are represented by the peaks of
relative abundance higher than 7% and by important peaks of lower
intensity. Crystals for EI-MS measurements and melting point
determinations were placed in glass capillaries, and KBr pellets
were prepared in a Labmaster 130 (mBraun) glovebox under
purified nitrogen (concentrations of oxygen and water were lower
than 2.0 ppm) and sealed with flame. IR spectra were measured in
an air-protecting cuvette on a Nicolet Avatar FT IR spectrometer
in the range 400-4000 cm-1. X-band EPR spectra were recorded
on an ERS-220 spectrometer (Center for Production of Scientific
Instruments, Academy of Sciences of GDR, Berlin, Germany)
operated by a CU-1 unit (Magnettech, Berlin, Germany). g values
were determined by using an Mn2+ standard at g ) 1.9860 (MI )
-1/2 line). An STT-3 variable-temperature unit was used for
measurements in the range -140 ( 25 °C. UV-near-IR spectra
in the range 300-1000 nm were measured on a Varian Cary 17D
spectrometer in all-sealed quartz cells (Hellma).
Chemicals. The solvents tetrahydrofuran (THF), hexane, and
toluene were dried by refluxing over LiAlH4 and stored as solutions
of green dimeric titanocene [(µ-η5:η5-C5H4C5H4)(µ-H)2{Ti(η5-
C5H5)}2].23 C6D6 (99.5% D) was degassed, distilled on a vacuum
line into a storage ampule containing dimeric titanocene, and stored
as its solution. The alkynes but-2-yne, hex-3-yne, 1-(trimethylsi-
lyl)prop-1-yne, 1-phenylprop-1-yne, phenyl(trimethylsilyl)ethyne,
bis(trimethylsilyl)ethyne, and tert-butyl(trimethylsilyl)ethyne and
olefins cis-/trans-but-2-ene, but-1-ene, hex-1-ene, tert-butylethene,
and cyclopentene (all Aldrich) were degassed by freeze/thaw cycles
and purified by dissolving the green dimeric titanocene until its
solution remained green. Then the reagents were distilled off in
ˇ
(24) (a) Steˇpnicˇka, P.; Gyepes, R.; C´ısaˇrova´, I.; Hora´cˇek, M.; Kubisˇta,
J.; Mach, K. Organometallics 1999, 18, 4869–4880. (b) Varga, V.;
ˇ
Petrusova´, L.; Cejka, J.; Hanusˇ, V.; Mach, K. J. Organomet. Chem. 1996,
ˇ
509, 235–240. (c) Varga, V.; Petrusova´, L.; Cejka, J.; Mach, K. J.
Organomet. Chem. 1997, 532, 251–259. (d) Hora´cˇek, M.; C´ısaˇrova´, I.;
ˇ
Cejka, J.; Karban, J.; Petrusova´, L.; Mach, K. J. Organomet. Chem. 1999,
577, 103–112.
(25) Pola´cˇek, J.; Antropiusova´, H.; Petrusova´, L.; Mach, K. J. Mol. Catal.
1991, 70, 9–28.
ˇ
(23) Antropiusova´, H.; Dosedlova´, A.; Hanusˇ, V.; Mach, K. Transition
Met. Chem. 1981, 6, 90–93.
(26) Hora´cˇek, M.; Kupfer, V.; Thewalt, U.; Steˇpnicˇka, P.; Pola´sˇek, M.;
Mach, K. Organometallics 1999, 18, 3572–3578.

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5543
Compound 3a. The above quantity of 1 was reacted with
diphenylethyne (0.712 g, 4.0 mmol in 15 mL) to give reddish brown
crystals. Yield 0.61 g (78%).
316 (8), 315 (9), 182 (7), 181 (15), 180 (10), 178 (10), 57 (22). IR
(KBr, cm-1): 2962 (vs), 2904 (vs), 2864 (s), 2721 (vw), 2187 (vw),
2153 (w), 1508 (w), 1494 (w), 1475 (s), 1437 (s, b), 1377 (vs),
1357 (s), 1295 (vw), 1264 (s), 1232 (m), 1206 (s), 1162 (vw), 1097
(m), 1079 (w), 1024 (s), 954 (vw), 923 (vw), 869 (vw), 825 (w),
802 (vw), 752 (w), 711 (w), 659 (vw), 615 (w), 529 (w), 496 (w),
458 (s), 414 (s). EPR (toluene, 23 °C): g ) 1.949, ∆H ) 20 G.
EPR (toluene, -140 °C): g1 ) 1.999, g2 ) 1.983, g3 ) 1.870, gav
) 1.950. UV-vis (toluene, nm): 438 . 610 (sh). Anal. Calcd for
C32H47Ti (479.59): C, 80.14; H, 9.88. Found: C, 80.08; H, 9.83.
Compound 3e. This compound was obtained from 1,4-bis(tri-
methylsilyl)buta-1,3-diyne) (0.39 g, 2.0 mmol) as red crystals. Yield:
0.69 g (86%).
Data for 3a are as follows. Mp: 155 °C. EI-MS (150 °C): m/z
(relative abundance) 497 (18), 496 (45), 495 (M•+; 100), 494 (20),
493 (19), 492 (7), 491 (11), 481 (7), 480 ([M - Me]+; 14), 483
(13), 465 ([M - 2 Me]+; 9), 389 (8), 361 (9), 319 (8), 318 (20),
317 ([M - L]+; 63), 316 (10), 315 (13), 313 (9), 181 (11), 178
(23). IR (KBr, cm-1): 3060 (w), 3051 (w), 3001 (m), 2960 (s),
2936 (s), 2902 (vs), 2861 (s), 2722 (vw), 1590 (s), 1582 (vw), 1570
(vw), 1532 (w), 1481 (s), 1439 (s), 1378 (s), 1312 (vw), 1199 (w),
1070 (w), 1022 (m), 902 (vw), 886 (vw), 832 (w), 786 (m), 758
(m), 748 (w), 699 (vs), 549 (vw), 530 (w), 511 (vw), 446 (s), 422
(m). EPR (toluene, 23 °C): g ) 1.948, ∆H ) 19 G. EPR (toluene,
-140 °C): g1 ) 1.9992, g2 ) 1.9820, g3 ) 1.863, gav ) 1.948.
UV-vis (toluene, nm): 370 (sh) . 500 > 650 (sh). Anal. Calcd
for C34H39Ti (495.54): C, 82.41; H, 7.93. Found: C, 82.38; H, 7.95.
Compound 3b. Reaction between 1 and 1-(trimethylsilyl)pro-
pyne (0.5 g, 5.3 mmol) afforded brown crystals highly soluble in
hexane upon cooling to solid CO2 temperature. Yield: 0.37 g (55%).
Data for 3e are as follows. Mp: 83 °C. EI-MS (90 °C): m/z
(relative abundance) 513 (15), 512 (28), 511 (M•+; 53), 510 (14),
509 (15), 496 ([M - Me]+; 5), 438 ([M - SiMe3]+; 9), 423 ([M
- SiMe3 - Me]]+; 4), 319 (23), 318 (68), 317 ([M - L]+; 100),
316 (32), 315 (33), 313 (13), 200 (12), 181 (20), 180 (11), 179 (9),
178 (12), 73 (32). IR (KBr, cm-1): 2954 (s), 2902 (s), 2863 (m,
sh), 2722 (vw), 2150 (vw), 2079 (vs), 1488 (w), 1441 (m), 1407
(w), 1380 (m), 1245 (s), 1163 (vw), 1077 (m), 1052 (w), 856 (vs),
840 (vs), 754 (s), 694 (w), 676 (m), 651 (w), 620 (vw), 616 (vw),
498 (w), 449 (m), 424 (m). EPR (toluene, 23 °C): g ) 1.946, ∆H
) 28 G. EPR (toluene, -140 °C): g1 ) 1.999, g2 ) 1.983, g3 )
1.865, gav ) 1.949. UV-vis (toluene, nm): 500 > 665 (sh). Anal.
Calcd for C30H47Si2Ti (511.74): C, 70.41; H, 9.26. Found: C, 70.46;
H, 9.29.
Data for 3b are as follows. Mp: 95 °C. EI-MS (90 °C): m/z
(relative abundance) 431 (20), 430 (40), 429 (M•+; 87), 428 (25),
427 (36), 426 (24), 425 (51), 424 (12), 423 (16), 414 ([M - Me]+;
14), 413 ([M - H - Me]+; 19), 412 ([M - 2H - Me]+; 22), 355
(9), 354 ([M - 2H - SiMe3]+; 18), 353 (11), 341 (9), 319 (19),
318 (53), 317 ([M - L]+; 100), 316 (28), 315 (38), 314 (13), 313
(28), 312 (9), 311 (17), 182 ([M - L - C5Me5]+; 19), 181 (34),
180 (22), 179 (17), 178 (28), 177 (18), 176 (13), 97 (41), 73 (46).
IR (KBr, cm-1): 2984 (sh), 2950 (s), 2901 (vs), 2858 (s), 2817
(m), 2720 (vw), 1613 (w), 1578 (vw), 1493 (m), 1434 (m, b), 1378
(s), 1240 (s), 1160 (vw), 1130 (vw), 1066 (vw), 1023 (m), 989
(vw), 970 (vw), 873 (s), 835 (vs), 769 (w), 751 (vw), 684 (w), 665
(vw), 621 (w), 566 (w), 514 (w), 449 (m), 414 (m). EPR spectrum
(hexane, 22 °C): g ) 1.9625, ∆H ) 8.5 G. UV-vis (hexane, nm):
480 > 610 (sh). Anal. Calcd for C26H41SiTi (429.56): C, 72.70; H,
9.62. Found: C, 72.75; H, 9.58.
Compound 3c. Reaction of 1 with phenyl(trimethylsilyl)ethyne
(0.5 g, 2.9 mmol) gave after evaporation of hexane a brown solid.
This was dissolved in 7.0 mL of toluene and crystallized by cooling
to -28 °C. A crop of brown crystals was recrystallized from
toluene. Yield: 0.17 g (23%). The mother liquor did not afford more
crystals and was further analyzed after chlorination with PbCl2 (see
below).
Compound 3f. This compound was prepared from 2,4-dipro-
pylbut-1-en-3-yne (head-to-tail dimer of 1-pentyne) (0.68 g, 5.0
mmol) to give brown crystals. Yield: 0.61 g (86%).
Data for 3f are as follows. Mp: 110-112 °C. EI-MS (110 °C):
m/z (relative abundance) 455 (12), 454 (30), 453 (M•+; 45), 452
(12), 451 (16), 449 (15), 440 (10), 439 (23), 438 ([M - Me]+;
58), 437 (17), 436 (18), 319 (10), 318 (35), 317 ([M - L]+; 100),
316 (19), 315 (23), 314 (9), 313 (19), 311 (13), 182 (14), 181 (25),
180 (17), 179 (11), 178 (17), 177 (13), 176 (8), 119 (7), 41 (13).
IR (KBr, cm-1): 3054 (w), 2953 (vs), 2897 (s), 2866 (s), 2721
(vw), 1604 (m), 1532 (m), 1492 (w), 1453 (s, b), 1376 (s), 1307
(vw), 1250 (vw), 1211 (vw), 1163 (vw), 1071 (vw), 1023 (m), 981
(vw), 907 (vw), 893 (vw), 855 (s), 739 (vw), 710 (w), 667 (vw),
596 (vw), 563 (w), 520 (vw), 507 (vw), 451 (m), 433 (m). EPR
(toluene, 23 °C): g ) 1.952, ∆H ) 12 G. EPR (toluene, -140
°C): g1 ) 1.999, g2 ) 1.982, g3 ) 1.881, gav ) 1.954. UV-vis
(toluene, nm): 495 > 630 (sh). Anal. Calcd for C30H45Ti (453.55):
C, 79.44; H, 10.00. Found: C, 79.50; H, 9.95.
Data for 3c are as follows. Mp: 140 °C. EI-MS (130 °C): m/z
(relative abundance) 493 (11), 492 (23), 491 (M•+; 50), 489 (14),
476 ([M - Me]+; 11), 475 ([M - HMe]+; 10), 418 ([M - SiMe3]+;
6), 417 ([M - SiHMe3]+; 7), 400 (12), 319 (13), 318 (33), 317
([M - L]+; 100), 316 (17), 315 (19), 313 (9), 182 (11), 181 (17),
178 (12), 73 (36). IR (KBr, cm-1): 3090 (vw), 3063 (w), 2976 (s,
b), 2902 (vs), 2861 (s), 2972 (vw), 1614 (vw), 1593 (w), 1572
(vw), 1488 (m), 1471 (s), 1437 (s), 1421 (m), 1379 (s), 1288 (vw),
1255 (m), 1239 (s), 1199 (vw), 1073 (vw), 1023 (m), 1000 (vw),
985 (vw), 911 (vw), 879 (vs), 833 (vs), 769 (s), 757 (s), 715 (s),
702 (s), 679 (w), 667 (w), 625 (w), 565 (w), 466 (w), 436 (m),
412 (m). EPR (toluene, 23 °C): g ) 1.948, ∆H ) 21 G. EPR
Compound 3g. This compound was obtained from 2,4-bis(tri-
methylsilyl)but-1-ene-3-yne (head-to-tail dimer of (trimethylsilyl)
ethyne) (1.0 mL, 5.0 mmol). The reaction required heating to 60
°C for 3 h. Brown crystals were obtained from hexane. Yield: 0.68 g
(85%).
Data for 3g are as follows. Mp: 135 °C. EI-MS (130 °C): m/z
(relative abundance) 514 (15), 513 (M•+; 22), 512 (12), 511 (19),
498 ([M - Me]+; 13), 440 ([M - SiMe3]+; 7), 319 (30), 318 (60),
317 ([M - L]+; 100), 316 (49), 315 (55), 314 (17), 313 (42), 312
(13), 311 (21), 196 (L•+; 47), 183 (12), 182 (32), 181 ([L - Me]+;
90), 180 (19), 179 (13), 178 (22), 177 (14), 156 (19), 155 (85),
119 (9), 108 (30), 97 (11), 83 (11), 74 (10), 73 (92), 45 (21), 43
(12). IR (KBr, cm-1): 3038 (vw), 3015 (vw), 2958 (s), 2904 (vs),
2858 (s), 2725 (vw), 1600 (w, b), 1486 (m), 1433 (s, b), 1378 (s),
1247 (s), 1166 (vw), 1149 (vw), 1067 (w), 1023 (m), 926 (w), 892
(w), 838 (vs), 807 (m), 755 (m), 725 (w), 692 (w), 620 (w), 566
(m), 516 (w), 474 (w), 430 (s). EPR (toluene, 23 °C): g ) 1.952,
∆H ) 15 G. EPR (toluene, -140 °C): g1 ) 1.999, g2 ) 1.982, g3
) 1.874, gav ) 1.952. UV-vis (toluene, nm): 464 > ∼600 (sh).
Anal. Calcd for C30H49Si2Ti (513.75): C, 70.13; H, 9.61. Found:
C, 70.06; H, 9.59.
(toluene, -140 °C): g1 ) 1.999, g2 ) 1.982, g3 ) 1.861, gav
)
1.947. UV-vis (toluene, nm): 370 (sh) . 458 > 700 (sh). Anal.
Calcd for C31H43SiTi (491.63): C, 75.73; H, 8.82. Found: C, 75.70;
H, 8.78.
Compound 3d. This compound was obtained from 2,2′,7,7′-
tetramethyl-octa-3,5-diyne (0.49 g, 3.0 mmol) as brown crystals.
Yield: 0.51 g (68%).
Data for 3d are as follows. Mp: 105 °C. EI-MS (100 °C): m/z
(relative abundance) 481 (18), 480 (47), 479 (M•+; 100), 478 (24),
477 (28), 476 (7), 475 (9), 465 (7), 464 ([M - Me]+; 16), 463 (7),
425 (10), 423 (14), 422 ([M - Bu]+; 26), 421 (9), 420 (10), 408
(7), 407 ([M - Bu - Me]+; 14), 318 (14), 317 ([M - L]+; 47),

5544 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
Preparation of 3h. Compound 1 (0.50 g, 1.57 mmol) was reacted
with 1-phenylprop-1-yne (0.26 g, 2.2 mmol) in 10 mL of hexane
to give a brown solution showing EPR and UV-vis spectra which
were attributable to 3h. Since all attempts for the product crystal-
lization gave only a brown wax, this was finally dried under vacuum
and used for the preparation of its chloro derivative 4h, which was
characterized (see below).
460 > 620 (sh). Anal. Calcd for C32H53Si3Ti (569.89): C, 67.42;
H, 9.37. Found: C, 67.40; H, 9.39.
Preparation of 3l. Compound 1 (0.50 g, 1.57 mmol) was reacted
with Me2Si(CtCCMe3)2 (0.40 g, 1.8 mmol) after warming the
reaction mixture to 60 °C for 1 h. After the concentrated solution
was cooled to -28 °C, brownish yellow crystalline material was
separated from a brown mother liquor. The product was recrystal-
lized from hexane to give dark yellow crystals. Yield: 0.73 g (87%).
Data for 3h are as follows. EPR (hexane, 22 °C): g ) 1.954,
∆H ) 21 G. UV-vis (hexane, nm): 485 . 640 (sh).
Preparation of 3i. Compound 1 (0.50 g, 1.57 mmol) was reacted
with hex-3-yne (0.4 g, 4.9 mmol) in 10 mL of hexane. The reaction
was complete after 1 h to give an ocher solution which displayed
EPR and UV-vis spectra attributable to 3i. Evaporation of all
volatiles yielded an ocher oil which did not crystallize. The oily
product was used for the preparation of 4i, which was characterized
(see below).
Data for 3l are as follows. Mp: 100-102 °C. EI-MS (100 °C):
m/z (relative abundance) 538 (6), 537 (M•+; 12), 522 ([M - Me]+;
2), 480 ([M - Bu]+; 2), 319 (29), 318 (77), 317 ([M - L]+; 100),
316 (36), 315 (38), 313 (11), 181 (14), 180 (10), 178 (9), 73 (18),
57 (13). IR (KBr, cm-1): 2953 (vs), 2901 (s), 2861 (m), 2798 (vw),
2720 (vw), 1589 (vw), 1514 (w), 1475 (m), 1460 (m), 1444 (m),
1377 (m), 1356 (m), 1286 (w), 1242 (m), 1192 (w), 1086 (w), 1073
(m), 1024 (w), 970 (vw), 952 (vw), 924 (vw), 836 (s), 814 (m),
775 (s), 764 (s), 697 (s), 614 (w), 579 (w), 496 (vw), 436 (m).
EPR (toluene, 23 °C): g ) 1.952, ∆H ) 20 G. EPR (toluene, -140
°C): g1 ) 1.999, g2 ) 1.982, g3 ) 1.883, gav ) 1.954. UV-vis
(toluene, nm): 455 > 615 (sh). Anal. Calcd for C34H53SiTi (537.74):
C, 75.94; H, 9.93. Found: C, 75.90; H, 9.90.
Preparation of 3m. A 0.5 mL amount of liquid ethene was
condensed at liquid nitrogen temperature and subsequently dissolved
in a solution of 1 (1.1 g, 3.5 mmol) in 20 mL of hexane. After the
mixture stood overnight at 20 °C, a clean brown solution was
carefully evaporated, and the residue was dissolved in 5 mL of
hexane. Cooling to -28 °C afforded a brown polycrystalline
material, which was collected. A slow recrystallization yielded, in
addition to a brown polycrystalline product, several red-brown
prisms as a very minor component less soluble in hexane. Their
analysis by X-ray diffraction indicated that the crystals contained
two pairs of molecules of 1 and 3m in the unit cell. Unfortunately,
the molecules were heavily disordered, which did not allow us to
determine the correct molecular parameters. The presence of 1 in
these crystals was confirmed by a very weak shoulder at 3018 cm-1
and an absorption band of medium intensity at 430 cm-1 in their
IR spectra. These bands were missing in IR spectra of the bulk of
3m. Yield: 1.05 g (87%).
Data for 3i are as follows. EPR (hexane, 22 °C): g ) 1.956, ∆H
) 14 G. UV-vis (hexane, nm): 495 (sh) > 580 (sh).
Preparation of 3j. A solution of 1 (0.50 g, 1.57 mmol) in hexane
(10 mL) was precooled to ca. -20 °C, and but-2-yne (0.14 mL,
1.75 mmol) was rapidly condensed from the gas phase into the
stirred solution. The purple color changed immediately to brownish
yellow. After the mixture was stirred for 30 s, all volatiles were
distilled off by condensation to liquid nitrogen temperature. A brown
residue was dissolved in a minimum amount of hexane and
crystallized at -28 °C. The first crop of crystals (0.14 g) was
separated and discarded, as their greenish coloration suggested the
presence of 2. The mother liquor was concentrated and cooled in
a freezer to give a brown fine polycrystalline material extremely
soluble in hexane. After separation from mother liquor and drying
under vacuum, a brown powder was obtained. Yield: 0.32 g (55%).
Data for 3j are as follows. Mp: 105 °C. EI MS (100 °C): m/z
(relative abundance, %) 373 (17), 372 (36), 371 (M•+; 74), 370
(29), 369 (33), 368 (37), 367 ([M - 2 H2]+; 100), 366 (23), 365
(32), 364 (8), 363 (15), 356 (13), 355 (25), 354 ([M - Me - H2]+;
45), 353 (17), 352 (15), 342 (16), 341 ([M - 2 Me]+; 24), 340
(10), 339 ([M - 2 Me - H2]+; 12), 318 (11), 317 ([M - L]+; 27),
316 (10), 315 (13), 314 (10), 313 (18), 254 (12), 202 (32), 201
(12), 200 (19), 199 (16), 195 (15), 183 (21), 182 (21), 181 (39),
180 (26), 179 (21), 178 (31), 177 (22), 176 (20), 175 (12), 167
(17), 166 (10), 165 (11), 164 (12), 163 (14), 152 (15), 151 (11),
150 (14), 135 (21), 133 (15), 120 (16), 119 (25), 105 (30), 93 (23),
91 (23), 79 (17), 77 (15). IR (KBr, cm-1): 2972 (m), 2906 (vs),
2860 (s), 2720 (vw), 1543 (w), 1493 (m), 1445 (s, b), 1378 (vs),
1309 (vw), 1023 (m), 807 (w), 615 (vw), 565 (w), 450 (m), 427
(m). EPR (toluene, 22 °C): g ) 1.957; ∆H ) 11.6 G. EPR (toluene,
-140 °C): g1 ) 2.000; g2 ) 1.982; g3 ) 1.894; gav ) 1.958.
UV-vis (toluene, nm): 475 (sh) > 630 (sh). Anal. Calcd for
C24H35Ti (371.39): C, 77.61; H, 9.50. Found: C, 77.66; H, 9.54.
Preparation of 3k. Compound 1 (0.50 g, 1.57 mmol) was reacted
with Me2Si(CtCSiMe3)2 (0.43 g, 1.7 mmol) in 10 mL of hexane.
The reaction was complete after 30 min at 60 °C. A dark yellow
product crystallized out from a concentrated solution. Recrystalli-
zation from hexane afforded dark yellow crystals. Yield: 0.83 g
(93%).
Data for 3m are as follows. Mp: 80-82 °C. EI-MS (80 °C): m/z
(relative abundance) 347 (11), 346 (22), 345 (M•+; 53), 344 (29),
343 (49), 342 (36), 341 ([M - 2 H2]+; 100), 340 (32), 339 (73),
338 (14), 337 (18), 319 (11), 318 (27), 317 ([M - C2H4]+; 67),
316 (26), 315 (26), 314 (11), 313 (24), 311 (16), 203 (16), 202
(10), 200 (13), 181 (27), 180 (18), 179 (19), 178 (27), 177 (22),
176 (15). EI-MS (15 eV, 70 °C): m/z (relative abundance) 347 (13),
346 (29), 345 (M•+; 100), 344 (10), 343 ([M - H2]+; 41), 342
(11), 341 ([M - 2 H2]+; 23), 340 (7), 339 (13), 319 (7), 318 (18),
317 ([M - C2H4]+; 63), 316 (14), 315 (10). IR (KBr, cm-1): 2906
(vs), 2857 (s), 2809 (m), 2722 (vw), 1487 (m), 1442 (s, b), 1378
(vs), 1312 (vw), 1202 (vw), 1067 (vw), 1023 (m), 896 (vw), 849
(w), 805 (w), 755 (vw), 723 (w), 680 (vw), 617 (vw), 563 (w),
517 (vw), 466 (w), 442 (s). EPR (toluene, 23 °C): g ) 1.959, ∆H
) 19 G. EPR (toluene, -140 °C): g1 ) 2.000, g2 ) 1.983, g3 )
1.897, gav ) 1.960. UV-vis (toluene, nm): 325 (sh), 375 (sh) .
444 > 560 (sh). Anal. Calcd for C22H33Ti (345.35): C, 76.51; H,
9.63. Found: C, 76.48; H, 9.60.
Preparation of Chlorinated Compounds 4a-m. Pure crystal-
line products 3a,b,d-g,k-m and crude products 3c,h-j were
dissolved in THF (10 mL), and the brown solutions were poured
onto degassed powdery PbCl2 (slightly more than 1/2 molar equiv).
After 15 min of vigorous stirring the solutions turned red and white
PbCl2 turned to black lead. THF was distilled off for another use,
and the residues were extracted with toluene. The products were
crystallized from concentrated toluene solution by cooling, and red
crystalline products were dried under vacuum.
Data for 3k are as follows. Mp: 90-95 °C. EI-MS (90 °C): m/z
(relative abundance) 569 (M•+; 4), 319 (13), 318 (37), 317 ([M -
L]+; 92), 316 (29), 315 (44), 314 (17), 313 (38), 312 (11), 311
(19), 253 (19), 252 (L.+; 67), 239 (33), 238 (64), 237 ([L - Me]+;
100), 181 (16), 180 (9), 179 (14), 178 (15), 177 (13), 155 (12),
151 (10), 111 (54), 97 (18), 83 (13), 73 (69). IR (KBr, cm-1):
2984 (m, sh), 2950 (s), 2898 (s), 2856 (m, sh), 2794 (w), 2721
(vw), 1550 (w), 1487 (w), 1436 (m), 1401 (w), 1244 (s), 1023 (w),
991 (s), 894 (s), 857 (vs), 834 (vs), 767 (s), 747 (m), 685 (m), 632
(m), 607 (vw), 565 (w), 550 (vw), 458 (m), 436 (s). EPR (toluene,
23 °C): g ) 1.942, ∆H ) 41 G. EPR (toluene, -140 °C): g1 )
1.998, g2 ) 1.980, g3 ) 1.842, gav ) 1.940. UV-vis (toluene, nm):

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5545
Preparation of 4a. Crystals of 3a (0.21 g, 0.42 mmol) reacted
with PbCl2 (0.07 g, 0.25 mmol) to give a bright red polycrystalline
powder. Yield: 0.21 g (94%).
-11.86 (SiMe3). Data for 4c′ (85%) are as follows. 1H NMR
(C6D6): -0.08 (s, 9H, SiMe3); 1.62 (s, 15H, C5Me5); 1.73, 1.77,
2
1.85, 2.62 (4 × s, 4 × 3H, C5Me4); 2.91, 3.25 (2 × d, 2 × JHH
)
16.8 Hz, 2 × 1H, C(6)H2); 6.88-7.22 (m, 5H, Ph). 13C{1H} NMR
(C6D6): 1.92 (SiMe3); 11.75, 11.99 (C5Me4); 12.71 (C5Me5); 13.20,
15.27 (C5Me4); 36.32 (C(6)); 118.60, 120.66, 124.20 (C5Me4);
124.55 (CH, Ph); 124.97 (C5Me5); 126.67 (CH, Ph); 128.99
(C5Me4); 129.62 (CH, Ph); 148.75, 153.56 (Cipso (Ph) and C5Me4);
163.63 (C(21)); 221.96 (C(22)). 29Si{1H} NMR (C6D6): -12.32
(SiMe3). EI-MS (200 °C): m/z (relative abundance) 528 (10), 527
(13), 526 (M•+; 16), 511 ([M - Me]+; 5), 491 (7), 490 ([M -
HCl]+; 14), 453 ([M - SiMe3]+; 5), 418 ([M - Cl - SiMe3]+;
5), 392 ([M - C5Me4CH2]+; 11), 355 (11), 354 (40), 353 (31),
352 ([M - L]+; 91), 351 (12), 350 (11), 317 ([M - L - Cl]+; 6),
220 (41), 219 (30), 218 ([M - L - C5Me4CH2]+; 100), 217 (32),
216 (26), 215 (11), 214 (7), 213 (19), 119 (14), 73 (57). IR (KBr,
cm-1): 3069 (vw), 3047 (w), 2998 (m), 2947 (s), 2896 (vs), 2844
(m, sh), 2719 (vw), 1590 (w), 1567 (vw), 1495 (m), 1473 (w), 1435
(m), 1376 (m), 1254 (m), 1243 (s), 1073 (vw), 1024 (m), 921 (vw),
885 (w), 844 (vs), 835 (vs), 768 (m), 755 (m), 707 (s), 680 (vw),
647 (w), 506 (w), 416 (s). UV-vis (hexane, nm): 445 (sh) > 540
(sh). Anal. Calcd for C31H43ClSiTi (527.08): C, 70.64; H, 8.22.
Found: C, 70.70; H, 8.28.
1
Data for 4a are as follows. Mp: 219 °C. H NMR (C6D6): 1.66
(s, 15H, C5Me5);1.68, 1.87, 1.93, 2.63 (4 × s, 4 × 3H, C5Me4);
2
3.14, 3.44 (2 × d, 2 × JHH ) 17.1 Hz, 2 × 1H, C(6)H2); 6.81-7.08
(m, 8H, Ph); 7.10-7.14 (m, 2H, CHortho, C(22)Ph). 13C{1H} NMR
(C6D6): 11.58, 11.78 (C5Me4); 12.79 (C5Me5); 13.76, 14.54 (C5Me4);
37.77 (C(6)); 118.01, 121.05 (C5Me4); 124.01, 125.36, 126.12,
131.80 others are obscured by stronger solvent signal (CH, Ph);
125.14 (C5Me5); 128.69, 132.10, 138.76, 143.70, 149.60 (C5Me4
and Cipso (Ph)); 157.35 (C(21)); 204.41 (C(22)). EI-MS (210 °C):
m/z (relative abundance) 532 (21), 531 (26), 530 (M•+; 47), 529
(22), 494 ([M - HCl]+; 9), 399 (13), 398 (42), 397 (39), 396 ([M
- C5Me4CH2]+; 100), 395 (26), 394 (14), 220 (28), 219 (23), 218
([M - L - C5Me4CH2]+; 76), 217 (29), 216 (24), 215 (13), 214
(8), 213 (23), 178 (21), 135 (15), 119 (17), 105 (12), 91 (10). IR
(KBr, cm-1): 3069 (w), 3048 (m), 3003 (s), 2946 (m), 2899 (vs),
2842 (m), 2717 (vw), 1938 (vw), 1878 (vw), 1808 (vw), 1589 (m),
1567 (vw), 1543 (vw), 1485 (s), 1437 (s), 1376 (s), 1311 (vw),
1243 (vw), 1193 (vw), 1152 (vw), 1071 (w), 1020 (m), 932 (vw),
888 (vw), 832 (vw), 783 (m), 762 (m), 746 (w), 700 (vs), 638 (vw),
579 (vw), 547 (vw), 531 (w), 499 (vw), 464 (w), 415 (s). UV-vis
(toluene, nm): 465 > 540 (sh). Anal. Calcd for C34H39ClTi (530.99):
C, 76.91; H, 7.40. Found: C, 76.96; H, 7.36.
Preparation of 4d. Compound 3d (0.25 g, 0.52 mmol) reacted
with PbCl2 (0.09 g, 0.32 mmol) to give bright red crystals from
hexane. Yield: 0.24 g (91%).
Preparation of 4b. Brown crystalline 3b (0.25 g, 0.58 mmol)
reacted with PbCl2 (0.09 g, 0.32 mmol) to give bright red crystals.
Yield: 0.20 g (75%).
Data for 4d are as follows. Mp: 180 °C. 1H NMR (C6D6): 1.31
(s, 9H, tCCMe3); 1.40 (s, 9H, C(21)CMe3); 1.58, 1.81, 1.99, 2.49
(4 × s, 4 × 3H, C5Me4); 1.96 (s, 15H, C5Me5); 2.86, 3.12 (2 × d,
Data for 4b are as follows. Mp: 195 °C. 1H NMR (C6D6): 0.40
(s, 9H, SiMe3); 1.58, 1.92, 1.93, 2.37 (4 × s, 4 × 3H, C5Me4);
2
2 × JHH ) 18.6 Hz, 2 × 1H, C(6)H2). 13C{1H} NMR(C6D6):
4
10.77, 11.74 (C5Me4); 12.98 (C5Me5); 13.82, 14.36 (C5Me4); 29.14
(CMe3); 29.78, 31.03 (2 × CMe3); 32.61 (CMe3); 37.97 (C(6));
89.58 (C(22)CtC); 113.02 (CtCCMe3); 114.73, 122.79 (C5Me4);
124.53 (C5Me5); 127.46, 132.52, 134.64 (C5Me4); 164.05 (C(21));
178.45 (C(22)). EI-MS (170 °C): m/z (relative abundance) 517 (13),
516 (15), 515 (18), 514 (M•+; 27), 502 (9), 501 (16), 500 (14),
499 ([M - Me]+; 32), 464 ([M - Me - Cl]+; 11), 463 ([M - Me
- HCl]+; 12), 457 ([M - Bu]+; (6), 382 (15), 381 (41), 380 (38),
379 ([M - C5Me5]+; 83), 378 (15), 377 (14), 221 (13), 220 (40),
219 (33), 218 ([M - L - C5Me4CH2]+; 100), 217 (44), 216 (31),
215 (23), 214 (15), 213 (42), 135 (16), 119 (30), 57 (56). IR (KBr,
cm-1): 2963 (vs), 2901 (vs), 2861 (s), 2720 (vw), 1530 (w), 1501
(m), 1445 (s, b), 1384 (m), 1376 (vs), 1358 (s), 1266 (s), 1240
(m), 1205 (m), 1103 (vw), 1066 (vw), 1020 (m), 843 (w), 753 (vw),
617 (w), 536 (w), 440 (s). UV-vis (hexane, nm): 452 > 535 (sh).
Anal. Calcd for C32H47ClTi (515.04): C, 74.62; H, 9.20. Found: C,
74.58; H, 9.23.
1.79 (s, 15H, C5Me5); 1.81 (d, JHH ) 1.2 Hz, 3H, C(7)Me); 2.81
2
2
4
(d, JHH ) 17.4 Hz, 1H, C(6)H2); 2.93 (dq, JHH ) 17.4 Hz, JHH
) 1.2 Hz, 1H, C(6)H2). 13C{1H} NMR (C6D6): 6.26 (SiMe3); 10.68,
12.40 (C5Me4); 12.78 (C5Me5); 14.20, 15.52 (C5Me4); 24.53
(C(21)Me); 40.47 (C(6)); 116.21, 123.20, 127.05, 132.14, 134.36
(C5Me4); 123.90 (C5Me5); 157.39 (C(21)); 212.91 (C(22)). 29Si{1H}
NMR (C6D6): -13.87 (SiMe3). EI-MS (180 °C): m/z (relative
abundance) 466 (15), 465 (14), 464 (M•+; 29), 451 (6), 449 ([M -
Me]+; 11), 428 ([M - HCl]+; 5), 355 (10), 354 (34), 353 (27),
352 ([M - L]+; 75), 351 (10), 350 (9), 332 (9), 331 (11), 330 ([M
- C5Me4CH2]+; 20), 329 (16), 317 ([M - Cl - L]+; 21), 221
(11), 220 (58), 219 (44), 218 ([M - L - C5Me4CH2]+; 100), 217
(52), 216 (33), 215 (16), 214 (9), 213 (26), 178 (9), 135 (8), 119
(18), 105 (9), 91 (7), 73 (25). IR (KBr, cm-1): 2987 (m), 2946 (s),
2898 (vs), 2863 (s), 2818 (m), 2716 (vw), 1520 (w), 1502 (m),
1434 (m, b), 1376 (s), 1294 (vw), 1256 (m), 1239 (s), 1065 (vw),
1020 (m), 881 (s), 841 (vs), 757 (w), 733 (w), 672 (m), 621 (w),
596 (vw), 517 (w), 466 (vw), 429 (m). UV-vis (hexane, nm): 435
(sh) > 540 (sh). Anal. Calcd for C26H41ClSiTi (465.01): C, 67.15;
H, 8.89. Found: C, 67.20; H, 8.92.
Preparation of 4e. The above procedure using 3e (0.33 g, 0.65
mmol) and PbCl2 (0.10 g, 0.36 mmol) afforded bright red crystals.
Yield: 0.22 g (62%).
1
Preparation of 4c/4c′. The mother liquor from 3c was evapo-
rated under vacuum, and the residue (0.54 g, 1.10 mmol) was
dissolved in THF and this solution reacted with PbCl2 (0.16 g, 0.57
mmol). A bright red waxy residue was obtained after evaporation
of toluene. It turned into a polycrystalline solid after long
Data for 4e are as follows. Mp: 154 °C. H NMR (C6D6): 0.28
(s, 9H, SiMe3); 0.38 (s, 9H, SiMe3); 1.54, 1.82, 1.95, 2.46 (4 × s,
4 × 3H, C5Me4); 1.94 (s, 15H, C5Me5); 2.78, 3.00 (2 × d, 2 ×
2JHH ) 18.6 Hz, 2 × 1H, C(6)H2). 13C{1H} NMR (C6D6): -0.37,
0.19 (2 × SiMe3); 10.71, 11.99 (C5Me4); 12.98 (C5Me5); 14.38,
14.87 (C5Me4); 35.31 (C(6)); 106.69, 115.60 (CtC); 113.71,
124.82, 127.49, 134.97, 140.18 (C5Me4); 125.17 (C5Me5); 166.79
(C(21)); 195.11 (C(22)). 29Si {1H}(C6D6): - 21.12 (tCSiMe3),
-11.81 (dCSiMe3). EI-MS (140 °C): m/z (relative abundance) 549
(9), 548 (13), 547 (12), 546 (M•+; 22), 531 ([M - Me]+; 12), 510
([M - HCl]+; 10), 495 ([M - Me - HCl]+; 7), 473 ([M -
SiMe3]+; 7), 414 (12), 413 (18), 412 (24), 411 ([M - C5Me5]+;
23), 396 ([M - Me - C5Me5]+; 7), 355 (8), 354 (27), 353 (22),
352 ([M - L]+; 62), 317 ([M - L - Cl]+; 9), 221 (8), 220 (38),
219 (29), 218 ([M - L - C5Me4CH2]+; 100), 217 (35), 216 (26),
215 (14), 214 (9), 213 (21), 135 (12), 119 (14), 73 (71). IR (KBr,
cm-1): 2989 (m, sh), 2954 (s), 2897 (s), 2823 (w, sh), 2720 (vw),
1
evacuation. H, 13C, and 29Si NMR spectra revealed that regioi-
somer 4c′ is contained in 85% abundance, whereas 4c is a minor
species (see Table 1). Yield: 0.53 g (93%).
Mp: 155 °C. Data for 4c (15%) are as follows. 1H NMR (C6D6):
0.10 (s, 9H, SiMe3); 1.84 (s, 15H, C5Me5); 1.89, 1.97 (2 × s, 2 ×
2
3H, C5Me4); 2.89, 3.16 (2 × d, 2 × JHH ) 18.6 Hz, 2 × 1H,
C(6)H2); other signals were not detected due to overlapping by
stronger signals of 4c′. 13C{1H} NMR (C6D6): 6.43 (SiMe3); 10.82,
12.53 (C5Me4); 12.89 (C5Me5); 14.46, 15.74 (C5Me4); 43.27 (C(6));
119.11, 121.69 (C5Me4); 122.96 (C5Me5); 124.05 (C5Me4); 124.55,
126.67, 129.62 (CH, Ph); 130.85, 133.99 (C5Me4); 145.84 (Cipso
(Ph)); 161.03 (C(21)); 215.05 (C(22)). 29Si{1H} NMR (C6D6):

5546 Organometallics, Vol. 27, No. 21, 2008
Pinkas et al.
2162 (vw), 2084 (s), 1494 (m), 1444 (m), 1403 (w), 1377 (m),
1245 (s), 1081 (m), 1045 (w), 1022 (w), 912 (vw), 854 (vs, b),
756 (m), 692 (w), 675 (w), 647 (w), 618 (vw), 482 (w), 444 (m),
430 (m), 417 (m). UV-vis (toluene, nm): 452 > 530 (sh). Anal.
Calcd for C30H47ClSi2Ti (547.19): C, 65.85; H, 8.66. Found: C,
65.90; H, 8.62.
Preparation of 4f. Crystalline 3f (0.32 g, 0.71 mmol) reacted with
PbCl2 (0.11 g, 0.40 mmol) to give a red solution which after the usual
workup yielded red crystals from hexane. Yield: 0.30 g (87%).
37.88 (C(6)); 118.92, 119.72 (C5Me4); 123.82 (CH, Ph); 124.85
(C5Me5); 126.73 (CH, Ph); 126.87, 129.67 (C5Me4); 130.00 (CH, Ph);
141.38 (C5Me4); 152.28 (Cipso, Ph); 157.32 (C(21)); 207.17 (C(22)).
EI-MS (170 °C): m/z (relative abundance) 468 (M•+; 2), 455 (6), 453
([M - Me]+; 10), 354 (14), 353 (7), 352 ([M - L]+; 20), 317 ([M -
L - Cl]+; 38), 220 (44), 219 (25), 218 ([M - L - C5Me4CH2]+;
100), 217 (27), 216 (25), 215 (12), 213 (24), 179 (21), 135 (12), 119
(14), 105 (11), 91 (8). IR (KBr, cm-1): 3072 (vw), 3053 (w), 2989
(m), 2950 (m), 2901 (vs), 2853 (s, sh), 2720 (vw), 1589 (w), 1550
(vw), 1489 (m), 1435 (s), 1376 (vs), 1154 (vw), 1070 (w), 1019 (s),
916 (w), 790 (m), 769 (w), 756 (m), 742 (w), 708 (s), 701 (s), 620
(vw), 572 (vw), 513 (w), 467 (w), 415 (s). UV-vis (hexane, nm):
453 > 535 (sh). Anal. Calcd for C29H37ClTi (468.91): C, 74.28; H,
7.95. Found: C, 74.32; H, 8.00.
Data for 4f are as follows. Mp: 135 °C. 1H NMR (C6D6): 0.99 (t,
3
3JHH ) 7.5 Hz, 3H, CH2CH2Me); 1.05 (t, JHH ) 7.5 Hz, 3H,
CH2CH2Me); 1.21-1.61 (m, 4H, 2 × CH2Me); 1.73, 1.74, 1.78, 2.49
(4 × s, 4 × 3H, C5Me4); 1.87 (s, 15H, C5Me5); 2.00-2.18 (m, 2H,
CH2CH2Me); 2.33-2.52 partially overlapped by stronger methyl signal
2
(m, 2H, CH2CH2Me); 2.94, 3.02 (2 × d, 2 × JHH ) 17.4 Hz, 2 ×
Preparation of 4i. The crude yellow oily 3i (0.48 g, 1.20 mmol)
reacted with PbCl2 (0.17 g, 0.62 mmol). Crystallization from hexane
yielded a fine, crystalline red solid. Yield: 0.59 g (87%).
2
1H, C(6)H2); 4.35, 4.77 (2 × d, 2 × JHH ) 3.3 Hz, 2 × 1H, dCH2).
13C{1H} NMR (C6D6): 11.14, 12.13 (C5Me4); 12.76 (C5Me5); 14.26,
the fourth overlapped by stronger C5Me5 signal (C5Me4); 14.74, 14.77
(2 × CH2CH2Me); 21.95, 23.82 (2 × CH2CH2Me); 34.96 (C(6));
36.10, 41.08 (2 × CH2CH2Me); 106.31 (dCH2); 118.62, 120.54
(C5Me4); 124.50 (C5Me5); 125.77, 130.05, 141.91 (C5Me4); 158.96
(CdCH2); 160.93 (C(21)); 208.90 (C(22)). EI-MS (130 °C): m/z
(relative abundance) 488 (M•+; 7), 473 ([M - Me]+; 5), 454 (12),
453 (32), 452 ([M - HCl]+; 80), 451 (11), 450 (10), 355 (12), 354
(23), 353 (28), 352 ([M - L]+; 29), 351 (13), 220 (49), 219 (37), 218
([M - L - C5Me4CH2]+; 100), 217 (45), 216 (37), 215 (22), 214
(15), 213 (40), 203 ([M - L - Me - C5Me4CH2]+; 11), 199 (12),
178 (10), 135 (51), 119 (42), 105 (21), 91 (22). IR (KBr, cm-1): 3058
(w), 2990 (m), 2955 (vs), 2901 (s), 2865 (s), 2838 (m), 2718 (vw),
1600 (w), 1589 (vw), 1531 (m), 1493 (m), 1452 (s), 1440 (s), 1376
(vs), 1311 (vw), 1253 (vw), 1081 (vw), 1064 (vw), 1021 (m), 877
(m), 745 (w), 715 (w), 672 (vw), 597 (w), 507 (w), 448 (w), 415 (m).
UV-vis (hexane, nm): 452 > 540 (sh). Anal. Calcd for C30H45ClTi
(489.00): C, 73.68; H, 9.28. Found: C, 73.65; H, 9.25.
Data for 4i are as follows. Mp: 200 °C. 1H NMR (C6D6): 0.95 (t,
3
3JHH ) 7.2 Hz, 3H, C(22)CH2Me); 0.99 (t, JHH ) 7.5 Hz, 3H,
C(21)CH2Me); 1.60 (s, 3H, C5Me4); 1.83 (s, 15H, C5Me5); 1.87-2.08
(m, partially overlapped 2H, C(21)CH2); 1.89, 1.94 (2 × s, 2 × 3H,
C5Me4); 2.15-2.30 (m, 1H, C(22)CH2); 2.41-2.58 (m, 1H,
2
C(22)CH2); 2.43 (s, 3H, C5Me4); 2.76, 2.84 (2 × d, 2 × JHH ) 16.8
Hz, 2 × 1H, C(6)H2). 13C{1H} NMR (C6D6): 11.05, 12.10 (C5Me4);
12.36 (C(22)CH2Me); 12.81 (C5Me5); 13.74 (C(21)CH2Me); 14.00,
15.04 (C5Me4); 24.02 (C(21)CH2); 32.45 (C(6)); 33.30 (C(22)CH2);
114.64, 123.02, 132.34, 133.61, the fifth signal is overlapped by solvent
signal (C5Me4); 123.68 (C5Me5); 149.25 (C(21)); 212.45 (C(22)). EI-
MS (190 °C): m/z (relative abundance) 436 (10), 435 (9), 434 (M•+
;
22), 421 (11), 420 (10), 419 ([M - Me]+; 26), 399 (13), 398 ([M -
HCl]+; 36), 383 ([M - HCl - Me]+; 15), 352 ([M - L]+; 5), 299
(11), 298 (9), 297 (25), 295 (17), 284 (11), 283 (16), 269 (12), 220
(42), 219 (42), 218 ([M - L - C5Me4CH2]+; 100), 217 (67), 216
(37), 215 (30), 214 (17), 213 (52), 201 (10), 199 (14), 181 (11), 178
(12), 177 (10), 135 (12), 119 (31), 105 (16), 91 (20), 77 (11). IR (KBr,
cm-1): 2960 (s), 2903 (vs), 2866 (s), 2849 (sh), 2821 (m), 2720 (vw),
1565 (w), 1502 (m), 1490 (m), 1434 (s), 1377 (vs), 1308 (w), 1296
(vw), 1263 (w), 1192 (vw), 1146 (vw), 1079 (vw), 1057 (w), 1020
(m), 956 (vw), 818 (vw), 778 (vw), 754 (vw), 614 (vw), 598 (vw),
468 (w), 448 (m), 411 (s). UV-vis (hexane, nm): 430 > 515. Anal.
Calcd for C26H39ClTi (434.89): C, 71.80; H, 9.04. Found: C, 71.82;
H, 9.05.
Preparation of 4g. Crystalline 3g (0.35 g, 0.68 mmol) reacted
with PbCl2 (0.11 g, 0.40 mmol) to give a red microcrystalline solid.
Yield: 0.24 g (64%).
Data for 4g are as follows. Mp: 162 °C. 1H NMR (C6D6): 0.29 (s,
9H, C(dCH2)SiMe3); 0.37 (s, 9H, C(22)SiMe3); 1.60, 1.92, 1.93, 2.56
(4 × s, 4 × 3H, C5Me4); 1.83 (s, 15H, C5Me5); 3.07, 3.22 (2 × d, 2
2
2
× JHH ) 17.4 Hz, 2 × 1H, C(6)H2); 5.39, 5.75 (2 × d, 2 × JHH
)
2.4 Hz, 2 × 1H, dCH2). 13C{1H} NMR (C6D6): 0.80, 8.17 (SiMe3);
10.88, 12.06 (C5Me4); 12.86 (C5Me5); 14.18, 15.84 (C5Me4); 40.93
(C(6)); 117.09, 123.52, 126.45, 131.30, 134.07 (C5Me4); 124.14
(C5Me5); 127.08 (dCH2); 157.11 (CdCH2); 166.03 (C(21)); 215.54
(C(22)). 29Si{1H} NMR (C6D6): - 14.13, - 5.80 (SiMe3). EI-MS
(170 °C): m/z (relative abundance) (548, M•+ not observed), 354 (54),
353 (24), 352 ([M - L]+; 65), 317 ([M - L - Cl]+; 30), 220 (46),
219 (27), 218 ([M - L - C5Me4CH2]+; 100), 217 (28), 216 (27),
215 (13), 213 (26), 181 (21), 119 (35), 73 (74). IR (KBr, cm-1): 3058
(w), 2980 (sh), 2955 (s), 2898 (vs), 2718 (vw), 1484 (m), 1444 (m),
1407 (m), 1375 (s), 1298 (vw), 1245 (vs), 1168 (vw), 1064 (vw), 1018
(m), 941 (m), 928 (w), 897 (s), 845 (vs, b), 787 (w), 756 (s), 689 (m),
672 (m), 646 (w), 623 (w), 595 (vw), 574 (vw), 534 (vw), 482 (vw),
455 (w), 424 (m), 409 (s). UV-vis (hexane, nm): 435 > 545 (sh).
Anal. Calcd for C30H49ClSi2Ti (549.20): C, 65.61; H, 8.99. Found: C,
65.58; H, 9.02.
Preparation of 4j. Crystalline 3j (0.25 g, 0.67 mmol) reacted with
PbCl2 (0.10 g, 0.35 mmol). After the usual workup procedure red
polycrystalline material was obtained. Yield: 0.21 g (78%).
1
Data for 4j are as follows. Mp: 95 °C. H NMR (C6D6, 323 K):
1.59 (s, 3H, C(21)Me); 1.62 (s, 3H, C5Me4); 1.80 (s, 3H, C(22)Me);
1.83 (s, 15H, C5Me5); 1.88, 1.94, 2.34 (3 × s, 3 × 3H, C5Me4); 2.75
(br s, 2H, C(6)H2). 13C{1H} NMR (C6D6, 323 K): 10.88, 12.08
(C5Me4); 12.71 (C5Me5); 13.85, 14.09 (C5Me4); 16.77 (C(21)Me); 29.57
(C(22)Me); 36.43 (C(6)); 114.28, 122.71 (C5Me4); 123.64 (C5Me5);
132.92, 134.74, the fifths is overlapped by solvent signal (C5Me4);
143.48 (C(21)); 206.98 (C(22)). EI MS (100 °C): m/z (relative
abundance, %) 408 (13), 407 (15), 406 (M•+; 21), 393 (9), 392 (8),
391 ([M - Me]+; 20), 370 ([M - HCl]+; 11), 356 (8), 355 ([M -
Me - HCl]+; 23), 354 (11), 353 (20), 272 ([M - C5Me4CH2]+; 10),
269 (10), 257 (12), 256 (12), 255 ([M - HC5Me5 - HCl]+; 29), 254
(7), 253 (12), 220 (38), 219 (33), 218 ([M - L - C5Me4CH2]+; 100),
217 (45), 216 (257), 215 (17), 214 (9), 213 (27), 135 ([C5Me5]+; 16),
119 (16), 105 (12), 91 (13). IR (KBr, cm-1): 2986 (m), 2949 (m, sh),
2902 (vs), 2836 (s), 2718 (vw), 1580 (w), 1498 (m), 1486 (m), 1442
(s), 1434 (s), 1375 (vs), 1298 (vw), 1190 (vw), 1064 (vw), 1048 (vw),
1021 (m), 956 (vw), 897 (vw), 829 (vw), 812 (vw), 789 (vw), 772
(vw), 689 (vw), 597 (vw), 499 (vw), 452 (m), 417 (s). UV-vis
(hexane, nm): 440 (sh) > 515. Anal. Calcd for C24H35ClTi (406.84):
C, 70.85; H, 8.67. Found: C, 70.86; H, 8.64.
Preparation of 4h. Crude compound 3h (0.52 g, 1.20 mmol)
reacted with PbCl2 (0.18 g, 0.64 mmol) in THF to give a red solution.
After evaporation of THF the residue was extracted with hexane.
Cooling of the concentrated solution afforded a red waxy solid. This
was, after drying under vacuum, used for its characterization.
Data for 4h are as follows. 1H NMR (C6D6): 1.53 (s, 3H, C(21)Me);
1.63 (s, 15H, C5Me5); 1.76, 1.78, 1.81, 2.53 (4 × s, 4 × 3H, C5Me4);
2
2.92, 3.00 (2 × d, 2 × JHH ) 17.4 Hz, 2 × 1H, C(6)H2); 6.96-7.03
(m, 1H, Ph); 7.17-7.26 (m, 4H, Ph). 13C{1H} NMR (C6D6): 11.31,
12.07 (C5Me4); 12.66 (C5Me5); 12.97, 14.33 (C5Me4); 19.44 (C(21)Me);

Insertion into Singly Tucked-in Titanocene
Organometallics, Vol. 27, No. 21, 2008 5547
Preparation of 4k. Crystalline 3k (0.37 g, 0.65 mmol) reacted
with PbCl2 (0.10 g, 0.36 mmol). After the usual workup procedure
yellowish brown crystalline material was obtained. Yield: 0.39 g (90%).
Data for 4k are as follows. Mp: 218 °C. 1H NMR (C6D6): 0.16 (s,
9H, C(21)SiMe3); 0.38 (s, 3H, SiMe2); 0.39 (s, 9H, C(24)SiMe3); 0.51
(s, 3H, SiMe2); 1.43, 1.74 (2 × s, 2 × 3H, C5Me4); 1.82 (s, 15H,
C5Me5); 2.12, 2.18 (2 × s, 2 × 3H, C5Me4); 2.86, 2.94 (2 × d, 2 ×
2JHH ) 19.5 Hz, 2 × 1H, CH2). 13C{1H} NMR (C6D6): -0.88
(C(21)SiMe3); 0.59, 3.43 (SiMe2); 3.48 (C(24)SiMe3); 10.11, 12.66
(C5Me4); 13.18 (C5Me5); 14.64, 14.75 (C5Me4); 31.04 (CH2); 116.31,
117.95, 121.39 (C5Me4); 124.04 (C5Me5); 128.78 (C5Me4); 133.04
(C(21)); 137.03 (C5Me4); 165.84 (C(22)); 167.90 (C(24); 264.56
(C(23)). 29Si{1H} NMR (C6D6): -14.82 (SiMe3); -5.65 (SiMe2); 4.82
(SiMe3). EI-MS (210 °C): m/z (relative abundance, %) 608 (12), 607
(25), 606 (51), 605 (50), 604 (M•+; 84), 603 (13), 602 (10), 569 ([M
- Cl]+; 5), 531 ([M - SiMe3]+; 5), 469 ([M - C5Me5]+; 5), 396
([M - C5Me5 - SiMe3]+; 7), 352 ([M - L]+; 5), 317 ([M - L -
Cl]+; 13), 252 ([L]+; 6), 237 ([L - Me]+; 7), 220 (37), 219 (28), 218
([M - L - C5Me4CH2]+; 100), 217 (33), 216 (24), 215 (10), 213
(16), 155 (11), 119 (10), 73 (81). IR (KBr, cm-1): 2987 (sh), 2950
(s), 2899 (s), 2792 (w), 2720 (vw), 1562 (w), 1493 (m), 1435 (m),
1402 (w), 1388 (w), 1358 (s), 1246 (s), 1021 (w), 978 (s), 922 (m),
880 (s), 856 (vs), 835 (vs), 768 (s), 747 (m), 690 (m), 674 (w), 662
(w), 634 (m), 467 (m), 421 (m). UV-vis (hexane, nm): 490 (sh) >
600 (sh). Anal. Calcd for C32H53Si3ClTi (605.34): C, 63.49; H, 8.82.
Found: C, 63.46; H, 8.80.
(vw), 1199 (w), 1163 (vw), 1117 (vw), 1060 (w), 1022 (m), 953 (vw),
926 (vw), 906 (vw), 871 (vw), 810 (vw), 680 (vw), 616 (w), 561 (vw),
549 (vw), 478 (w), 415 (s). UV-vis (hexane, nm): 395 (sh) > 475 (sh).
Anal. Calcd for C22H33ClTi (380.82): C, 69.38; H, 8.73. Found: C, 69.39;
H, 8.78.
X-ray Crystallography. Single crystals or crystal fragments of
3a-g,k,l and 4b,e,g,l,m were mounted into Lindemann glass capillaries
in a Labmaster 130 glovebox (mBraun) under purified nitrogen. Diffraction
data for all complexes except 3a were collected on a Nonius KappaCCD
diffractometer (Mo KR radiation, λ ) 0.710 73 Å) and processed by the
HKL program package.27 Data for 3a were collected on a CCD Xcalibur
S (Mo KR radiation, λ ) 0.710 73 Å) using ꢀ-scan rotation. The phase
problem was solved by direct methods (SIR97),28 followed by consecutive
Fourier syntheses, and refined by full-matrix least squares on F2 (SHELXL-
97).29 Relevant crystallographic data are given in Table 5. All non-
hydrogen atoms were refined anisotropically. Hydrogen atoms were
included in idealized positions and refined isotropically using the riding
model, except for the hydrogen atoms on the methylene C(6) atom in
3b,e and 4b,e,g,l, the C(16) and C(26) atoms in two independent molecules
of 3k, the exo methylene C(27) atom in 3g, and the C(24) atom in 4g.
These were found on difference Fourier maps and refined isotropically
without any restraints.
Computational Details. DFT calculations have been performed at
the Computer Center of the J. Heyrovsky Institute of Physical Chemistry
of Academy of Sciences of the Czech Republic, v.v.i., using Gaussian
03, Revision C.02.31 The transition state of 3j was determined using the
6-31+G(d) basis set on all atoms and the BPW91 functional.32 The
Hessian needed for the geometry optimization was computed analytically.
Vibration analysis for the transition-state molecule was done at the
stationary point reached by the optimization procedure after checking for
the presence of one (and only one) imaginary vibration. Vibrations and
molecular orbitals were visualized by Molden.33
Preparation of 4l. Crystalline 3l (0.32 g, 0.61 mmol) reacted with
PbCl2 (0.09 g, 0.33 mmol) in THF to give bright red crystals from
hexane. Yield: 0.32 g (92%).
1
Data for 4l are as follows. Mp: 205 °C. H NMR (C6D6): 0.43,
0.48 (2 × s, 2 × 3H, SiMe2); 1.14 (s, 9H, C(21)CMe3); 1.26 (s, 9H,
C(24)CMe3); 1.44, 1.69 (2 × s, 2 × 3H, C5Me4); 1.86 (s, 15H, C5Me5);
2
2.23, 2.26 (2 × s, 2 × 3H, C5Me4); 2.77, 2.90 (2 × d, 2 × JHH
)
19.5 Hz, 2 × 1H, CH2). 13C{1H} NMR (C6D6): 0.85, 5.17 (SiMe2);
10.71 (C5Me4); 13.36 (C5Me5); 13.49, 14.38, 15.46 (C5Me4); 28.49
(CH2); 30.43 (C(21)CMe3); 32.61 (C(24)CMe3); 35.45 (C(24)CMe3);
37.88 (C(21)CMe3); 117.00, 117.47, 121.96 (C5Me4); 124.73 (C5Me5);
131.59 (C5Me4); 137.08, 137.21 (C(21) and C5Me4); 149.09 (C(22));
170.42 (C24)); 240.69 (C(23)). 29Si{1H} NMR (C6D6): -6.89 (SiMe2).
EI-MS (200 °C): m/z (relative abundance, %) 574 (7), 573 (7), 572
(M•+; 13), 439 (6), 437 ([M - C5Me5]+; 11), 221 (8), 220 (41), 219
(27), 218 ([M - L - C5Me4CH2]+; 100), 217 (24), 216 (18), 213 (9),
73 (15). IR (KBr, cm-1): 2989 (m), 2945 (vs), 2899 (vs), 2858 (s),
2718 (vw), 1592 (vw), 1558 (vw), 1493 (m), 1481 (w), 1461 (m),
1437 (m), 1406 (w), 1387 (w), 1375 (s), 1359 (m), 1238 (s), 1204
(w), 1086 (w), 1055 (vs), 1020 (m), 919 (vw), 838 (vs), 819 (w), 778
(w), 764 (s), 696 (m), 673 (w), 615 (vw), 581 (vw), 499 (vw), 421
(m). UV-vis (hexane, nm): 470 (sh) . 660. Anal. Calcd for
C34H53ClSiTi (573.19): C, 71.24; H, 9.32. Found: C, 71.19; H, 9.28.
Preparation of 4m. Crystalline 3m (0.40 g, 1.16 mmol) reacted with
PbCl2 (0.18 g, 0.64 mmol) in THF (20 mL) to give a brown-yellow
solution. Cooling of the concentrated solution afforded brown crystals.
Yield: 0.40 g (91%).
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).
Supporting Information Available: CIF files for the structures
of 3a-g,k,l and 4b,e,g,l,m and text giving the experimental procedure
for obtaining 1, a table giving the makeup of compounds 3a-m and their
UV-vis and ESR spectra, a table giving UV-vis spectral data for 4a-m,
figures giving 1D NOESY NMR spectra for 4a,b,c′,d,4g-j,m, text giving
the full ref 31, tables giving crystal data and Platon drawings at 30%
probability for structures 3a-g,k,l and 4b,e,g,l,m, and a figure giving the
optimized geometry of molecule 2a with important interatomic distances.
This material is available free of charge via the Internet at http://pubs.acs.org.
OM800691F
(27) (a) Otwinowski, Z.; Minor, W.; HKL Denzo and Scalepack Program
Package; Enraf-Nonius, Delft, The Netherlands. For a reference, see: (b)
Otwinowski, Z.; Minor, W. Methods Enzymol. 1997, 276, 307–326.
(28) Altomare, A.; Burla, M. C.; Camalli, M.; Cascarano, G.; Giacovazzo, C.;
Guagliardi, A.; Polidori, G J. Appl. Crystallogr. 1994, 27, 435–436.
(29) Sheldrick, G. M. SHELXL97: Program for Crystal Structure
Refinement from Diffraction Data; University of Go¨ttingen, Go¨ttingen,
Germany, 1997.
(30) Spek, A. L. PLATON, A Multipurpose Crystallographic Tool;
Utrecht University, Utrecht, The Netherlands, 2007.
(31) Frisch, M. J., et al. Gaussian 03, Revision C.02; Gaussian, Inc.,
Wallingford, CT, 2004 (see the full reference in the Supporting Informa-
tion).
(32) (a) Becke, A. D. Phys. ReV. A 1988, 38, 3098–3100. (b) Perdew,
J. P.; Chevary, J. A.; Vosko, S. H.; Jackson, K. A.; Pederson, M. R.; Singh,
D. J.; Fiolhais, C. Phys. ReV. B 1992, 46, 6671–6687.
(33) Schaftenaar, G.; Noordik, J. H. Molden: a pre- and post-processing
program for molecular and electronic structures. J. Comput.-Aided Mol.
Design 2000, 14, 123–134.
1
Data for 4m are as follows. Mp: 215 °C. H NMR (C6D6): -0.42
(ddd, JHH ) 5.4 Hz, JHH ) 11.1 Hz, JHH )12.6 Hz, 1H, TiCH2); 1.39,
1.44, 1.68, 2.52 (4 × s, 4 × 3H, C5Me4); 1.78 (s, 15H, C5Me5); 1.88-1.96
(m, 1H, TiCH2); 2.34-2.58 (m, 2H, TiCH2CH2); 2.66-2.83 (m, 2H,
C5Me4CH2). 13C{1H} NMR (C6D6): 10.44, 11.29, 11.91 (C5Me4); 12.22
(C5Me5); 14.77 (C5Me4); 25.64 (C5Me4CH2); 44.67 (TiCH2CH2); 80.58
(TiCH2); 115.18, 116.57, 117.97, 133.07, 143.09 (C5Me4); 122.20 (C5Me5).
EI-MS (210 °C): m/z (relative abundance) 382 (9), 381 (8), 380 (M•+;
20), 365 ([M - Me]+; 6), 354 (11), 353 (9), 352 (M - L]+; 24), 345
(12), 344 ([M - HCl]+; 33), 246 ([M - C5Me4CH2]+; 13), 221 (9), 220
(47), 219 (30), 218 ([M - L - C5Me4CH2]+; 100), 217 (25), 216 (25),
215 (8), 214 (6), 213 (13), 203 (9), 199 (8), 135 (13), 119 (15), 91 (11).
IR (KBr, cm-1): 3053 (vvw), 2980 (m), 2910 (vs, b), 2853 (s), 2829 (s),
2720 (vw), 1493 (m), 1435 (m), 1377 (s), 1312 (vw), 1301 (w), 1234