Transition-metal compounds containing alkynylsilyl groups - Cyclopentadienyl complexes

Article abstract of DOI:10.1002/ejic.201200707

The synthesis of (alkynylsilyl)cyclopentadienyl complexes of titanium and manganese was studied. The titanium compounds PhC≡CMe₂SiC ₅H₄CpTiCl₂ (1) and (PhC≡CMe ₂SiC₅H₄)₂

Full text of DOI:10.1002/ejic.201200707

FULL PAPER
DOI: 10.1002/ejic.201200707
Transition-Metal Compounds Containing Alkynylsilyl Groups –
Cyclopentadienyl Complexes
Florian Hoffmann,[a] Jörg Wagler,[a] and Gerhard Roewer*[a]
Keywords: Manganese / Titanium / Alkynylsilyl compounds / Cyclopentadienyl ligands
The synthesis of (alkynylsilyl)cyclopentadienyl complexes of
titanium and manganese was studied. The titanium com-
pounds PhCϵCMe2SiC5H4CpTiCl2 (1) and (PhCϵCMe2-
SiC5H4)2TiCl2 (2) were prepared by treating LiC5H4Si-
Me2CϵCPh with suitable titanium(IV) halides. The manga-
nese compound PhCϵCMe2SiC5H4Mn(CO)3 (3) could be
synthesized by treating Mn(CO)5Cl with TlC5H4Si-
Me2CϵCPh or LiC5H4SiMe2CϵCPh. Alternatively, the alk-
ynylation of ClMe2SiC5H4Mn(CO)3 (6) with PhCϵCMgBr
was also successful. In contrast, the direct complexation of
(alkynylsilyl)cyclopentadiene or the direct alkynylsilylation
of cymantrene were not feasible. Redox reactions and the de-
silylation of the cyclopentadienyl ring were hampering side
reactions in all routes but to varying extent. All three com-
plexes were characterized by NMR spectroscopy. 1 and 3
were also studied by IR and UV/Vis spectroscopy. The molec-
ular and crystal structure of compound 1 was determined by
X-ray diffraction analysis.
metathesis of an (alkynylsilyl)cyclopentadienide],[4] and one
of manganese [prepared by the reaction of a (chloro-
silyl)cyclopentadienyl complex with a lithium acetylide][5]
reported, which bear alkynylsilyl groups, whereas the corre-
sponding oligosilyl compounds are completely unknown.
However, there is a number of related (alkenyl- or allenylsil-
yl)cyclopentadienyl complexes.[6]
Herein, we present a comparative assessment of synthetic
routes leading to (alkynylsilyl)cyclopentadienyl complexes,
as well as two new examples of such compounds.[7]
Introduction
Recently, we reported the synthesis of some alkynylsilyl–
transition-metal complexes with a metal–silicon bond, as
well as mild subsequent reactions preserving this reactive
bond.[1] An alternative approach towards alkynylsilyl-func-
tionalized complexes, which circumvents the sensitivity is-
sues associated with the direct metal–silicon bond, is the
insertion of a cyclopentadienyl spacer unit between the
metal and the silicon atom, that is, the synthesis of (alk-
ynylsilyl)cyclopentadienyl complexes. The metal–carbon
and carbon–silicon bonds are more robust than a direct
metal–silicon bond, while the silyl group prevents side reac-
tions, which could occur, if the alkynyl residue was bound
directly to the aromatic ring (conjugated π system) or
through one carbon atom (activation of propargylic C–H
bonds). This spacer unit should allow the complexes to re-
sist less mild conditions, when they are used as starting ma-
terials in further reactions.
Results and Discussion
The number of synthetic pathways to cyclopentadienyl
complexes with silyl groups is larger than that for silyl com-
plexes with a metal–silicon bond, because the Si–C bond is
kinetically inert and the metal complex fragments are quite
robust. Thus, the alkynyl group, the silyl group, and the
metal-complex fragment can be connected in several se-
quences depending on the reactivity of the complex frag-
ment. In reactive fragments, for example, dichloridodicyclo-
pentadienyltitanium derivatives (titanocene dichlorides),
the (alkynylsilyl)cyclopentadienyl ligand has to be attached
to the metal center as a complete ligand, because the Ti–Cl
bonds do not allow for selective reactions at the cyclopen-
tadienyl rings or the silyl group. In less reactive fragments,
for example, tricarbonylcyclopentadienylmanganese deriva-
tives (cymantrenes), the silyl group can be introduced into
the cyclopentadienyl complex and even be modified later
on.
To our surprise, a literature search revealed that, apart
from a notable number of ferrocene derivatives mainly used
in materials science,[2] there are only a few cyclopentadienyl
complexes of rare-earth metals (Y, Lu, Sc; formed by ring
openingandrearrangementof2-furylsubstituentsonthesilicon
atom),[3] two of cobalt and titanium each [prepared by salt
[a] Institut für Anorganische Chemie, Technische Universität
Bergakademie Freiberg,
Leipziger Str. 29, 09596 Freiberg, Germany
Fax: +49-3731-39-4058
E-mail: Gerhard.Roewer@chemie.tu-freiberg.de
Homepage: http://tu-freiberg.de/fakult2/aoch/agsi/
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201200707.
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Cyclopentadienyl–Transition-Metal Complexes with Alkynylsilyl Groups
Titanium Compounds
Considering the above-said, dichlorido(η5-cyclopenta-
dienyl){η5-[dimethyl(phenylethynyl)silyl]cyclopentadienyl}-
titanium(IV) (1), PhCϵCMe2SiC5H4CpTiCl2, was synthe-
sized by treating trichlorido(η5-cyclopentadienyl)titanium,
CpTiCl3, with lithium [dimethyl(phenylethynyl)silyl]cyclo-
pentadienide, LiC5H4SiMe2CϵCPh, in tetrahydrofuran
(THF) (Scheme 1). The order of mixing of the starting ma-
terials had some influence on the yield and the purity of
the target product. When the lithium salt was added to
CpTiCl3, 1 was obtained in 53% yield, whereas the inverse
order gave a product of lower purity in 34% yield. This is
attributed to redox reactions caused by the excess of lithium
salt in the second case. Compound 1 forms laminar red
crystals with a tinge of violet. They can be handled in air
and are sparingly soluble in nonpolar and well soluble in
Figure 1. Molecular structure of 1. Selected bond lengths [pm] and
angles [°]: Ti1–Cp(C1–C5) 206.32(9), Ti1–Cp(C6–C10) 206.11(9),
Ti1–C10 241.29(19), Ti1–Cl1 237.90(6), Ti1–Cl2 237.23(6), Si1–
C10 188.0(2), Si1–C11 186.3(2), Si1–C12 185.7(2), Si1–C13
185.3(2), C13–C14 121.0(3), C14–C15 144.8(3); Cl1–Ti1–Cl2
96.40(2), Cp(C1–C5)–Ti1–Cp(C6–C10) 131.24(10), Ti1–C10–Si1
128.94(9), C10–Si1–C11 113.74(9), C10–Si1–C12 109.57(9), C10–
Si1–C13 104.23(9), C11–Si1–C12 113.13(10), C11–Si1–C13
106.11(10), C12–Si1–C13 109.55(10), Si1–C13–C14 176.8(2), C13–
C14–C15 77.8(2), Cl1–Ti1–C10–Si1 38.48(11), Ti1–C10–Si1–C13
151.36(11).
1
polar solvents. The H, 13C, and 29Si NMR spectroscopic
data are consistent with the molecular structure of 1. The
49Ti NMR spectrum shows a signal at δ = –747 ppm (full
width a half-maximum height Δν1/2 = 100 Hz), which is in
the range characteristic of titanocene dichlorides.[8]
The bonding parameters of compound 1 are similar to
those of related complexes (Figure 1).[9,10] The molecules
form layers parallel to the bc plane (Figure 2a). These layers
consist of a “core” of titanocene dichloride fragments and
a “cover” of dimethyl(phenylethynyl)silyl groups. The titan-
ocene dichloride fragments within such a layer feature inter-
molecular CH···Cl bridges (Figure 2b), a phenomenon that
has been reported before for this type of complexes.[11]
Neighboring layers interact through weak CH···π contacts
between the phenylethynyl and the dimethylsilyl groups.
Apparently, this layered structure is the origin of the lami-
nar appearance of the crystals of 1.
Figure 2. (a) Crystal structure of 1 (view into a layer, hydrogen
atoms omitted for clarity). (b) CH···Cl contacts in 1 [view onto a
layer, phenyl hydrogen atoms omitted for clarity, HCp···Cl
(CCp···Cl) distances in pm: d1 = 294 (357), d2 = 257 (352); sum of
the van der Waals radii: 310 pm (380 pm)].[12]
The analogous bis(alkynylsilyl)-substituted complex
dichloridobis{η5-[dimethyl(phenylethynyl)silyl]cyclopenta-
dienyl}titanium(IV) (2), (PhCϵCMe2SiC5H4)2TiCl2,[4] was
synthesized in the same manner as 1 from LiC5H4Si-
Me2CϵCPh and TiCl4·2THF in THF (Scheme 1). How-
ever, the reaction was not as clean as for 1, and again, the impure viscous oil. Repeated attempts of recrystallization
order of mixing of the starting materials had significant in- did not lead to a solid product. Therefore, satisfying ele-
fluence on the yield and the purity of the product. When mental analyses could not be obtained. However, the syn-
the lithium salt was added to the titanium tetrachloride, thesis of solid 2 by using hexane as solvent was recently
yields were low and erratic. This was attributed to the oxid- reported (including a crystal-structure determination),[4]
izing and Lewis-acidic properties of TiIV, which lead to TiIII which emphasizes the influence of the reaction conditions.
compounds and side reactions of the alkyne. Adding the
1H, 13C [attached-proton test (APT)], and 29Si NMR
starting materials in the inverse order resulted in a 64% spectra, which are consistent with the molecular structure
yield of 2 but only after a workup that included the ad- of 2 and literature data, verify the identity of the com-
dition of carbon tetrachloride for the reoxidation[13] of low- pound. The 49Ti NMR spectrum features an intense signal
valent titanium species, and that afforded the product as an at δ = –726 ppm (Δν1/2 = 270 Hz), which is in the range
Scheme 1. Synthesis of compounds 1 and 2.
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F. Hoffmann, J. Wagler, G. Roewer
FULL PAPER
characteristic of titanocene dichlorides.[8] In addition, 1 and proved less straightforward, and all of the above-mentioned
the complex trichlorido{η5-[dimethyl(phenylethynyl)silyl]- pathways had to be examined.
The simplest way to synthesize tricarbonyl{η5-[dimethyl-
cyclopentadienyl}titanium(IV), PhCϵCMe2SiC5H4TiCl3,
[δ(49Ti) = –366 ppm][8b] were identified as byproducts.[14]
In conclusion, [(alkynylsilyl)cyclopentadienyl]titanium
complexes can be prepared by treating substituted lithium
cyclopentadienides with titanium(IV) halides, but the abil-
ity of the lithium salts to act as a reducing agent is a draw-
back of this method. Possibly, this could be circumvented
by: (1) the use of thallium cyclopentadienides, which have a
markedly decreased reducing ability, (2) the use of titani-
um(III) halides, which leads to the formation of titanocene
monohalides which can then be oxidized to the correspond-
ing dihalides,[15] or (3) the use of zirconium and hafnium
halides, which are not reduced by lithium cyclopentadien-
ides.[16]
(phenylethynyl)silyl]cyclopentadienyl}manganese(I)
PhCϵCMe2SiC5H4Mn(CO)3, seemed to be the reaction of
cyclopentadienyldimethyl(phenylethynyl)silane, PhCϵ
(3),
CMe2SiCp, with Mn2(CO)10 (route 1). This method gives
good results for substituted cymantrenes[17] and cyman-
trene, CpMn(CO)3, itself (see Exp. Sect.). Nevertheless, with
PhCϵCMe2SiCp in refluxing nonane at 150 °C,[18] only de-
composition occurred, and CpMn(CO)3 was the only iden-
tifiable product. Similar observations are reported for the
preparation of (trimethylsilyl)cymantrene, Me3SiC5H4-
Mn(CO)3, according to this route.[19] Apparently, this path-
way is not applicable to silylcymantrenes in general.
Another economic synthesis should be route 2, but the
reaction of lithiated cymantrene, (OC)3MnC5H4Li, with
chlorodimethyl(phenylethynyl)silane, PhCϵCMe2SiCl (–
78 °C, exclusion of light), resulted in a mixture of com-
pounds containing 3 only in minor amounts. Thus, this
pathway, which otherwise works well with many electro-
philes[20] or with lithiated ferrocene,[2b] proved to be inef-
ficient. This may be due to insufficient exclusion of light,
which can lead to interactions of the CϵC triple bond with
the lithiated cymantrene, which undergoes photosubstitu-
tion easily.[20]
Manganese Compounds
For alkynylsilyl-substituted cymantrenes, four synthetic
pathways can be deduced by retrosynthesis: (1) the reaction
of an (alkynyl)(cyclopentadienyl)silane with decacarbonyl-
dimanganese Mn2(CO)10, (2) the reaction of lithiated cym-
antrene with an alkynylhalosilane, (3) the reaction of lithi-
ated cymantrene with a protected halosilane and the subse-
quent transformation into an alkynylsilane, and (4) the re-
action of an alkynylsilyl-substituted cyclopentadienide
Route 3 circumvents this problem by introducing the alk-
ynyl group only in the last step. A variation of this pathway
was used for the synthesis of the only known (alkynylsilyl)-
cymantrene.[5] At first, (OC)3MnC5H4Li is silylated with
chloro(diethylamino)dimethylsilane, Et2NMe2SiCl, which
anion
with
a
pentacarbonylmanganese(I)
halide
(Scheme 2). Although one should thus expect the synthesis
of a cymantrene derivative to be easily accomplished, it
leads
to
tricarbonyl{η5-[(diethylamino)dimethylsilyl]-
cyclopentadienyl}manganese(I) (4), Et2NMe2SiC5H4Mn-
(CO)3 (Scheme 3). Subsequent reactions with methanol/
chlorotrimethylsilane (methanol alone did not react) and
acetyl chloride furnished tricarbonyl[η5-(methoxydimethyl-
silyl)cyclopentadienyl]manganese(I)
C5H4Mn(CO)3,[21] and tricarbonyl[η5-(chlorodimethylsilyl)-
cyclopentadienyl]manganese(I) (6), ClMe2SiC5H4Mn-
(5),
MeOMe2Si-
(CO)3,[22] respectively. Finally, the addition of (phenylethyn-
yl)magnesium bromide, PhCϵCMgBr, to 6 and workup re-
sulted in a 90% crude yield of 3 as a brown oil. All these
reactions were monitored by NMR spectroscopy. The spec-
tra indicated that a small amount of a byproduct was
formed in the first step. This byproduct is very similar to 4
and follows all of its transformations [Δδ(29Si) = 0.1 ppm],
Scheme 2. Synthetic pathways for (alkynylsilyl)cymantrenes.
Scheme 3. Synthesis of 3 via 4, 5, and 6.
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Cyclopentadienyl–Transition-Metal Complexes with Alkynylsilyl Groups
that is, the only difference between the two compounds can Reactivity of the Triple Bond
be the ligands on the manganese atom. Most likely a carb-
The CϵC triple bond can undergo complexation inter-
onyl substitution occurred, probably with THF.[20] Unfortu-
nately, this byproduct could not be removed, neither by
recrystallization nor by chromatography on silica gel, and
thus prevented the isolation of pure solid 3. In conclusion,
route 3 is a practicable synthetic pathway, if high purity is
not demanded.
molecularly as well as intramolecularly, and it can also take
part in bond forming reactions. The required free coordina-
tion sites at the metal center can be furnished by inherently
labile ligands or by ligand dissociation upon chemical reac-
tions or upon UV irradiation. With appropriate transition-
metal moieties, for example, the labile (phospane)cobalt
compound bis(triphenylphosphane)(η5-cyclopentadienyl)-
cobalt(I), CpCo(PPh3)2, the reaction does not stop at the
alkyne complex stage, and carbon–carbon bond coupling
reactions occur.[25] However, in the intermolecular reaction
of 1 or 2 with CpCo(PPh3)2, redox reactions between TiIV
and CoI prevented the isolation of an alkyne complex or
any other product. In a reference experiment, chloridotris-
(triphenylphosphane)cobalt(I), (Ph3P)3CoCl, was treated
with LiC5H4SiMe2CϵCPh to form an intramolecular com-
plex via the intermediate {η5-[dimethyl(phenylethynyl)silyl]-
cyclopentadienyl}bis(triphenylphosphane)cobalt(I), (Ph3P)2-
CoC5H4SiMe2CϵCPh (cf. ref.[25]). In a second reference ex-
periment, compound 1 was reduced with magnesium in
THF to remove the chlorido ligands and to form a complex
with the alkynyl group, either intra- or intermolecularly.[26]
Unfortunately, in both cases, neither could a defined prod-
uct be isolated, nor could any intermediate or final complex
be detected by NMR spectroscopy, although color changes
indicated that a reaction had taken place.
Route 4 comprises the reaction of alkynylsilyl-substituted
lithium or thallium cyclopentadienides with a pentacarb-
onylmanganese(I) halide. Preliminary tests showed that
when unsubstituted sodium cyclopentadienide (NaCp) is
used, redox reactions interfere with the synthesis, and a
considerable amount of Mn2(CO)10 forms, which is in con-
trast to literature results.[23a] Better results were obtained
with thallium cyclopentadienide (TlCp), which led to only
minor amounts of Mn2(CO)10.[23b] Similar observations
were made with LiC5H4SiMe2CϵCPh and thallium [di-
methyl(phenylethynyl)silyl]cyclopentadienide
(TlC5H4Si-
Me2CϵCPh) [prepared in situ from the lithium salt and
thallium(I) chloride, TlCl]. LiC5H4SiMe2CϵCPh reacted
with chloridopentacarbonylmanganese(I), Mn(CO)5Cl, to
afford 3 and Mn2(CO)10 in comparable amounts both in
THF and benzene. Thus, only low to moderate yields of
impure target compound were obtained. By using
TlC5H4SiMe2CϵCPh instead, 3 was prepared as the main
product (Scheme 4). The proportion of Mn2(CO)10 was
only approximately 15% and could be removed by sublima-
tion. Unsubstituted CpMn(CO)3, formed by desilylation,
was observed in the sublimate as a byproduct, too. The sub-
sequent recrystallization of the residue finally gave 3 in 58%
yield as an orange-yellow low-melting solid.
Irradiation-induced ligand substitutions are quite com-
mon, also for silyl[27] and stannyl[28] complexes with unsatu-
rated hydrocarbons. Consequently, a solution of compound
3 was irradiated with UV light and monitored by IR and
NMR spectroscopy,[29] but only decomposition occurred,
and the free silane ligand PhCϵCMe2SiCp was detected.
Spectroscopic Properties
Scheme 4. Synthesis of
Me2CϵCPh or TlC5H4SiMe2CϵCPh.
3
from Mn(CO)5Cl and LiC5H4Si-
Selected 29Si NMR and IR spectroscopic data of the syn-
thesized complexes are listed in Tables 1 and 2. In compari-
son with the free ligand,[30] the complexation of a cyclopen-
tadienyl group in a silane causes a decrease in 29Si shielding,
because electron density is transferred to the metal cen-
ter.[31,32] This low-field shift was found to be 5–7 ppm for
the (alkynylsilyl)cyclopentadienyl complexes 1, 2, and 3, re-
sulting in signals ranging between δ = –23 and –25 ppm.[4,30]
1
The H, 13C, and 29Si NMR spectra are consistent with
the molecular structure of 3 in number, intensity, and cou-
pling patterns of the signals. The features of the 55Mn
NMR signal (δ = –2140 ppm, Δν1/2 = 23 kHz) are typical
for cymantrene derivatives.[24] The IR spectrum of 3 shows
three characteristic bands at 2161, 2024, and 1944 cm–1,
which were assigned to the CϵC vibration and the carbonyl
ligands, respectively. A crystal structure analysis was not
possible, because the solid consisted of very thin fibrous
“crystals”. Nevertheless, the identity of 3 was verified by
the analytical and spectroscopic data.
In conclusion, the synthesis of 3 was unexpectedly com-
plicated by the decomposition of the ligand, substitutions
at the manganese atom, or redox reactions. Out of the four
routes presented above, only the reaction of Mn(CO)5Cl
with TlC5H4SiMe2CϵCPh proved efficient to afford 3 as a
pure, solid product.
Table 1. 29Si NMR spectroscopic data of compounds 1–6.[a]
2
1
Compound
δ
1JSiCϵC JSiCϵC JSiC5H4
[ppm] [Hz]
[Hz]
[Hz]
(PhCϵCMe2SiC5H4)CpTiCl2 (1) –24.6
(PhCϵCMe2SiC5H4)2TiCl2 (2) –24.7
(PhCϵCMe2SiC5H4)Mn(CO)3 (3) –23.2
(Et2NMe2SiC5H4)Mn(CO)3 (4) –3.4
(MeOMe2SiC5H4)Mn(CO)3 (5)[c] +7.2
(ClMe2SiC5H4)Mn(CO)3 (6) +19.2
90
89
92
–
–
–
17
16
18
–
–
–
72
72
74
[b]
–
–
[b]
[b]
–
[a] For 29Si NMR spectroscopic data of the free ligand, see ref.[30]
[b] Satellites too weak or hidden. [c] Ref.[21b]
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F. Hoffmann, J. Wagler, G. Roewer
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(161.98 MHz), 49Ti (22.56 MHz), and 55Mn (98.97 MHz) measure-
ments were 85% H3PO4, TiCl4, and 0.08 m KMnO4 in H2O (δ =
–0.8 ppm), respectively.[34] For 29Si NMR spectra, the INEPT
(INEPT = insensitive nuclei enhanced by polarization transfer)
pulse sequence was employed. IR spectra were recorded with a Spe-
cord M 82 (VEB Carl Zeiss JENA) or a Nicolet 510 spectrometer.
Liquid samples were prepared between NaCl plates, whereas solids
were examined in KBr disks. UV/Vis spectra were recorded with a
Specord S 100 (Analytik Jena AG) in the range 190–1000 nm.
Table 2. IR data of compounds 1–3.[a]
Compound
ν(CϵC) [cm–1
]
ν(C=O) [cm–1
]
˜
˜
(PhCϵCMe2SiC5H4)CpTiCl2 (1)
(PhCϵCMe2SiC5H4)2TiCl2 (2)
2157,[b] 2151[c]
2156[b]
–
–
(PhCϵCMe2SiC5H4)Mn(CO)3 (3) 2161[d]
2024, 1944[d]
2018, 1930[e]
2158[e]
[a] For IR data of the free ligand, see ref.[30] [b] Solution in toluene.
[c] KBr pellet. [d] Solution in hexane. [e] Neat liquid.
Chemicals: Solvents were dried and deoxygenated by distillation
under argon from sodium/benzophenone (benzene, diethyl ether,
hexane, THF, toluene, triethylamine), calcium hydride (chloroform,
1
The H and 13C NMR signals appeared in the expected
ranges. The alkyne carbon atoms feature signals in the
range δ = 90–108 ppm, and the signal of the silicon-bound deuterated chloroform, decaline, dichloromethane, nonane), lith-
carbon atom is always at higher field (assignment by 29Si
ium aluminium hydride (pentane), or magnesium (methanol) and
were stored under argon until use. Chlorotrimethylsilane was dis-
satellites).
tilled and stored under argon before use. Acetyl chloride was dis-
The UV/Vis spectra of the synthesized compounds con-
tilled from iron powder and stored under argon until use. Dicyclo-
sist of very intense aromatic absorptions at 200–300 nm and
pentadiene was dried with calcium hydride. The silane ligands
one or more bands with medium to low intensity in the
PhCϵCMe2SiCp and LiC5H4SiMe2CϵCPh were synthesized as
near-UV or visible region, which are responsible for the
color of the complexes. A comparison showed the spectra
of the compounds to be simple superimpositions of the
spectra of their components, “transition metal complex
previously reported.[30] CpTiCl3 was prepared from Cp2TiCl2 and
TiCl4 in xylene,[35] and TiCl4·2THF was prepared from TiCl4 and
THF in CH2Cl2.[36] CpMn(CO)3 was prepared from dicyclopenta-
diene and Mn2(CO)10. Although this reaction is mentioned in the
fragment” and “alkynylsilyl group”,[33] with no or only literature,[37a] we could not find a published procedure. Thus, the
experimental details are given below. Mn(CO)5Cl was prepared
from Mn2(CO)10 and sulfuryl chloride, SO2Cl2, in CH2Cl2.[38]
Chromatography was performed on “Silicagel L5/40” from LACH-
EMA (Brno)/CHEMAPOL (Prague). The other chemicals were
prepared according to common procedures or purchased from
commercial suppliers and were used as received.
small bathochromic shifts. This means that there is no or
only a weak conjugation between the component chromo-
phores.
Conclusions
Crystal Structure Analysis: The X-ray single-crystal structure
analysis was performed with a Bruker-Nonius X8 diffractometer
by using Mo-Kα radiation (λ = 71.073 pm) and an APEX2-CCD
area detector. For the solving, refinement, and visualization of the
structure the programs Bruker SMART,[39a] Bruker SAINT,[39a]
[(Alkynylsilyl)cyclopentadienyl]titanium and -manganese
complexes are accessible by complexation of the corre-
sponding substituted lithium or thallium cyclopentadien-
ides with suitable metal halides. For the preparation of
manganese compounds, the alkynylation of (halosilyl)cym- SHELXS-97,[39b] SHELXL-97,[39c] and ORTEP32[39d] were used.
The thermal ellipsoids are drawn at the 50% probability level. Crys-
tal structure data and determination details of complex 1: molecu-
lar formula: C20H20Cl2SiTi; M = 407.25 gmol–1; T = 93(2) K; λ
= 71.073 pm; crystal system: monoclinic; space group: P21/c; a =
1240.39(14) pm, b = 1371.92(16) pm, c = 1235.00(14) pm; α = 90°,
β = 112.647(3)°, γ = 90°; V = 1939.6(4)ϫ106 pm3 (= Å3); Z = 4;
ρcalcd. = 1.395 gcm–3; μ = 0.777 mm–1; F(000) = 840; crystal size =
0.21ϫ0.15ϫ0.10 mm; θ range = 1.78–27.50°; hkl ranges = –10 Յ
h Յ 16, –16 Յ k Յ 17, –16 Յ l Յ 15; reflections collected/unique
= 16873/4440; Rint = 0.0478; completeness = 100.0%; absorption
correction: semi-empirically from equivalents; maximal/minimal
transmission = 0.9300/0.8162; refinement method: full-matrix least-
squares on F2; data/restraints/parameters = 4440/0/217; GoF (F2)
= 1.028; R1/wR2 [IՆ2σ(I)] = 0.0323/0.0697, R1/wR2 (all data) =
antrene derivatives is a useful alternative. In contrast, the
complexation of (alkynylsilyl)cyclopentadienes or the direct
alkynylsilylation of cyclopentadienyl complexes are not
feasible. Redox reactions of the cyclopentadienides and the
desilylation of the cyclopentadienyl ring are hampering side
reactions in all routes. However, their extent can be dimin-
ished by properly choosing starting materials and reaction
procedure.
Experimental Section
General Remarks: All operations were performed under purified
argon by using standard Schlenk-line or glovebox techniques. If
possible, reactions were monitored by NMR or IR spectroscopy.
Assignments were made by comparison of the spectra with each
other and with literature data. Missing NMR peaks are hidden by
other peaks, often by those of the solvent. Melting points were
determined between thin glass plates (in air) or in sealed capillaries
(under argon) with a Boëtius-type heating microscope with a heat-
ing rate of about 4 Kmin–1. Elemental analyses were performed
0.0514/0.0747; ρres (maximal/minimal)
=
0.394ϫ10–6 epm–3/
–0.285ϫ10–6 epm–3 (= eÅ–3). CCDC-642191 (for 1) contains the
supplementary crystallographic data for this paper. These data can
be obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Tricarbonyl(η5-cyclopentadienyl)manganese(I)
Mn2(CO)10 (980 mg, 2.51 mmol), dicyclopentadiene C10H12
(Cymantrene):
in duplicate with a CHN-O-Rapid (Heraeus), and the values were (2.0 mL, 1960 mg, 14.9 mmol), and decaline (6 mL) were heated to
averaged. The NMR spectra were recorded at 22 °C with a Bruker
DPX 400 Avance spectrometer by using tetramethylsilane, Me4Si,
reflux (oil bath temperature of ca. 200 °C). A gas evolution started,
which ceased after 6 h. After 9 h of heating, the reaction mixture
was cooled to room temperature, filtered, and cooled to –20 °C. A
yellow solid deposited, which was separated, washed with cold hex-
1
as internal standard for H (400.13 MHz), 13C (100.63 MHz), and
29Si (79.49 MHz) measurements. The external standards for 31P
6022
www.eurjic.org
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2012, 6018–6026

Cyclopentadienyl–Transition-Metal Complexes with Alkynylsilyl Groups
ane, and dried in vacuo (yield: 600 mg, 59%). Cooling of the
mother liquor to –78 °C yielded an additional precipitate (yield:
350 mg, 34%). The crude product (950 mg, 93%) was sublimated
in vacuo, which resulted in yellow crystals. The final product was
very pure, and Mn2(CO)10 could not be detected by 55Mn NMR
C5H4CpTiCl2), 399 (br., 3000, C5H4CpTiCl2), 539 (br., 300,
C5H4CpTiCl2) nm (Lmol–1 cm–1).[42b,43e]
Dichloridobis{η5-[dimethyl(phenylethynyl)silyl]cyclopentadienyl}-
titanium(IV) (2): TiCl4·2THF (1000 mg, 2.99 mmol) in THF
(50 mL) was added to LiC5H4SiMe2CϵCPh (1400 mg, 6.08 mmol)
in THF (50 mL) at 0 °C with stirring. The deep red-brown solution
was then warmed to room temperature, and the solvents were evap-
orated in vacuo. The residue was extracted with CCl4 (1 mL) and
CH2Cl2 (5ϫ 4 mL). After 3 d, the extract was concentrated in
vacuo, and the residue was treated with CH2Cl2 (10 mL). This ex-
tract was reduced in vacuo to half its volume and layered with
hexane (10 mL). After mixing and cooling to –78 °C, a red oil de-
posited, which was separated, washed with hexane (3ϫ 1 mL), and
dried in vacuo (1370 mg, 81% crude yield). It was redissolved in
diethyl ether (3 mL) and layered with hexane (6 mL). After mixing
and cooling to –20 °C, a very viscous dark red oil deposited which
was separated, washed with hexane (3ϫ 1 mL), and dried in vacuo.
Yield: 1085 mg, 1.92 mmol, 64%. Solubility: CH2Cl2, chloroform,
1
spectroscopy. Yield: 735 mg, 3.60 mmol, 72%. H NMR (CDCl3):
1
δ = 4.76 (s,[40] Δν1/2 = 2 Hz, JHC = 179 Hz) ppm. 13C NMR
(CDCl3): δ = 224.8 (br., Δν1/2 = 50 Hz, CO), 82.7 (s, Δν1/2 = 5 Hz,
Cp) ppm. 55Mn NMR (CDCl3): δ = –2160 (br., Δν1/2 = 8.5 kHz)
ppm. UV/Vis (hexane): λ (ε) = 216 (15000), 332 (1000) nm
(Lmol–1 cm–1).[41]
Dichlorido(η5-cyclopentadienyl){η5-[dimethyl(phenylethynyl)silyl]-
cyclopentadienyl}titanium(IV) (1): A solution of LiC5H4Si-
Me2CϵCPh (490 mg, 2.13 mmol) in THF (25 mL) was added to
CpTiCl3 (467 mg, 2.13 mmol) in THF (25 mL) at room tempera-
ture with stirring. After 6 h, the solvent was evaporated from the
red solution in vacuo, and the residue was extracted with CH2Cl2.
The extract was concentrated in vacuo (to 4 mL) and layered with
hexane (8 mL). After mixing and cooling to –20 °C for several days,
dark-red crystals and a light-red solid deposited, which were sepa-
1
toluene, diethyl ether; insoluble in hexane. H NMR (0.12 molL–1
in CDCl3): δ = 7.49 (m, 4 H, Phortho), 7.31 (m, 6 H, Phmeta+para),
3/4
3/4
7.06 (“t”,
J
HH
= 2.4 Hz, 4 H, C5H4), 6.73 (“t”,
J
HH
= 2.4 Hz,
rated, washed with diethyl ether (2ϫ 2 mL), and dried in vacuo
(360 mg, 42% crude yield). The mother liquor yielded further crude
product, after reducing its volume in vacuo and cooling (repeated
twice, 245 mg, 29 % crude yield). The combined solids (605 mg,
71% crude yield) were sorted under the microscope to give 510 mg
(59%) of dark red crystals of the product. They were then redis-
solved in CH2Cl2 (3 mL) and layered with hexane (6 mL). After
mixing and cooling to –20 °C, dark red crystals deposited after
several days and were separated, washed with diethyl ether (3ϫ
1 mL), and dried in vacuo (330 mg, 38%). Cooling of the mother
liquor to –78 °C yielded additional product (125 mg, 14%). The
4 H, C5H4), 0.52 (s, JHC = 121 Hz, 12 H, SiMe2) ppm. 13C NMR
1
(0.12 molL–1 in CDCl3): δ = 132.0 (s, 4 C, Phortho), 130.7 (s, 4 C,
1
C5H4), 129.0 (s, 2 C, Phpara), 128.3 (s, 4 C, Phmeta), 126.2 (s, JCSi
= 73 Hz, 2 C, C5H4), 122.6 (s, 2 C, Phipso), 121.6 (s, 4 C, C5H4),
107.3 (s, 2 C, CϵC–Si), 91.9 (s, 2 C, CϵC–Si), 0.1 (s, 1JCSi = 60 Hz,
4 C, SiMe2) ppm. 29Si NMR (0.12 molL–1 in CDCl3): δ = –24.7 [s
2
1
(1H-coupled: sept, JSiH = 7.0 Hz), JSiC(Me) = 60 Hz (2 C),
1JSiC(C5H4) = 72 Hz (1 C), JSiC(CϵC) = 89 Hz (1 C), JSiC(CϵC)
=
1
2
16 Hz (1 C)] ppm. 49Ti NMR (0.12 molL–1 in CDCl3): δ = –726
(Δν1/2 = 270 Hz) ppm. IR (toluene): ν = 2156 [ν(CϵC)] cm–1.
˜
crystals were suitable for X-ray crystallography. The product is air- Tricarbonyl{η5-[dimethyl(phenylethynyl)silyl]cyclopentadienyl}-
stable for some time but should be stored under argon. Yield:
455 mg, 1.12 mmol, 53%. M.p. 99–101 °C (argon), 97–98 °C (air).
Solubility: CH2Cl2, chloroform; moderately in toluene; sparingly in
diethyl ether; insoluble in hexane. C20H20Cl2SiTi (407.252): calcd.
manganese(I) (3)
(a) Synthesis via Tricarbonyl{[η5-(diethylamino)dimethylsilyl]-
cyclopentadienyl}manganese(I) (4), Tricarbonyl[η5-(methoxydimeth-
ylsilyl)cyclopentadienyl]manganese(I) (5), and Tricarbonyl[η5-
(chlorodimethylsilyl)cyclopentadienyl]manganese(I) (6)
1
C 58.99, H 4.95; found C 58.70, H 4.78. H NMR (0.25 molL–1 in
CDCl3): δ = 7.52 (m, 2 H, Phortho), 7.34 (m, 3 H, Phmeta+para), 7.06
3/4
nBuLi in hexane (2.5 m, 0.95 mL, 2.38 mmol) was diluted with hex-
ane (4 mL) and added to a solution of CpMn(CO)3 (408 mg,
2.00 mmol) in THF (20 mL) cooled to –78 °C with exclusion of
light. After 1 h at –78 °C, Et2NMe2SiCl (0.4 mL, 360 mg,
2.17 mmol) in hexane (4.5 mL) was added slowly. After warming
up to room temperature and stirring overnight, an orange-brown
solution of 4 was obtained [29Si NMR (THF): δ = –3.4 (s) ppm].
(“t”,
J
J
HH
= 2.4 Hz, 2 H, C5H4), 6.67 (s, 5 H, Cp), 6.65 (“t”,
3/4
1
= 2.4 Hz, 2 H, C5H4), 0.50 (s, JHC = 122 Hz, 6 H, SiMe2)
HH
ppm. 13C NMR (0.25 molL–1 in CDCl3): δ = 132.0 (s, 2 C, Phortho),
129.5 (s, 2 C, C5H4), 129.1 (s, 1 C, Phpara), 128.4 (s, 2 C, Phmeta),
124.7 (s, 1 C, C5H4), 122.7 (s, 2 C, C5H4), 122.4 (s, 1 C, Phipso),
120.7 (s, 5 C, Cp), 107.6 (s, 1 C, CϵC–Si), 91.5 (s, 1 C, CϵC–Si),
1
0.1 (s, JCSi = 60 Hz, 2 C, SiMe2) ppm. 29Si NMR (0.25 molL–1 in
2
1
CDCl3): δ = –24.6 [s (1H-coupled: sept, JSiH = 7.1 Hz), JSiC(Me)
To this solution was added methanol (500 μL, 396 mg, 12.3 mmol)
and then chlorotrimethylsilane (300 μL, 257 mg, 2.37 mmol) at
room temperature with stirring and exclusion of light. After 1 h,
triethylamine (100 μL, 73 mg, 0.72 mmol) was added to neutralize
excess acid. After leaving the mixture overnight, the solvent was
evaporated in vacuo. The residue was extracted with hexane
(40 mL) to yield a yellow solution of 5 [29Si NMR (hexane): δ =
+7.2 (s) ppm].[21b]
1
1
= 60 Hz (2 C), JSiC(C5H4) = 72 Hz (1 C), JSiC(CϵC) = 90 Hz (1 C),
2JSiC(CϵC) = 17 Hz (1 C)] ppm. 49Ti NMR (0.25 molL–1 in CDCl3):
δ = –747 (Δν1 / 2 = 100 Hz) ppm. IR (toluene): ν = 2157
˜
[ν(CϵC)] cm–1. IR (KBr): ν = 3114 [m, ν(CHCp/C5H4/Ph)], 3093 [m,
˜
ν(CHCp/C5H4/Ph)], 3055 [vw, ν(CHCp/C5H4/Ph)], 2963 [w, νas(CH3)],
2930 [vw, ν(CH)], 2920 [vw, ν(CH)], 2891 [vw, νs(CH3)], 2151 [m,
ν(CϵC)], 1592 [vw, ν(C=CPhCϵC)], 1570 [vw, ν(C=CPhCϵC)], 1485
[w, ν(C=CP h C ϵ C )], 1450 [w/sh, ν(C=CC 5 H 4 )], 1442 [m,
ν(C=CPhCϵC)], 1408 [m, δas(SiCH3)], 1374 [w, ν(C=CCp/C5H4)], 1323
(vw), 1247 [m, δs(SiCH3)], 1218 [w, δ(CHPhCϵC)], 1180 (w),
1072 [vw, δ(CHP h C ϵ C )], 1051 [w, δ(CHC 5 H 4 )], 1023 [w,
δ(CHCp/C5H4/PhCϵC)], 901 [vw, δ(CHPhCϵC)], 847 [s, γ(CHC5H4) +
ρ(SiCH3)], 821 [s, γ(CHCp) + ρ(SiCH3)], 786 [s, ρ(SiCH3)], 757 [m,
This solution was concentrated in vacuo (to 10 mL) with exclusion
of light and mixed with acetyl chloride (5.0 mL, 830 mg,
70.4 mmol). After 3 d of stirring at room temperature, the solvent
was evaporated in vacuo to yield 6 as an oily, orange-brown solid
[29Si NMR (hexane): δ = +19.2 (s) ppm].
γ(CHPhCϵC)], 690 [m, γ(CHPhCϵC)], 675 (w/sh), 631 (vw), 601 (w), This solid was then redissolved in diethyl ether (15 mL), and (phen-
538 (w), 436 (m), 422 (m) cm–1.[37b,42a,43] UV/Vis (CH2Cl2): λ (ε) =
ylethynyl)magnesium bromide, PhCϵCMgBr, in diethyl ether,
251 (25000, C5H4CpTiCl2 + PhCϵC), 260 (22000, C5H4CpTiCl2 + which was prepared by heating magnesium (85 mg, 3.50 mmol),
PhCϵC), 273 (14000, C5 H4 CpTiCl2 ), 316 (br/sh, 5000, 1,2-dibromoethane (1 droplet), ethyl bromide (300 μL, 438 mg,
Eur. J. Inorg. Chem. 2012, 6018–6026
© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
6023

F. Hoffmann, J. Wagler, G. Roewer
FULL PAPER
4.02 mmol), and phenylacetylene, PhCϵCH (375 μL, 349 mg,
3.42 mmol), to reflux in diethyl ether (8.5 mL) for 4 h,[44] was added
slowly at room temperature. After stirring at room temperature
overnight, the mixture was cautiously hydrolyzed with a 10 %
NH4Cl solution (4ϫ 10 mL), washed with water (3ϫ 10 mL), and
dried with Na2SO4. Removal of the diethyl ether in vacuo yielded
a brown oil, which was redissolved in hexane (5 mL). After fil-
tration and cooling to –78 °C, a brown oil deposited, which was
separated, washed with pentane (2ϫ 2 mL), and dried in vacuo
(650 mg, 90% yield). Recrystallization or chromatography on silica
gel had little effect on the purity but diminished the yield consider-
ably.
ν(CϵO)], 1594 [w, ν(C=CPhCϵC)], 1573 [vw, ν(C=CPhCϵC)], 1488
[m, ν(C=CPhCϵC)], 1441 [m, ν(C=CPhCϵC)], 1404 [m, δas(SiCH3)],
1369 [m, ν(C=CC5H4)], 1307 (w), 1254 [s, δs(SiCH3)], 1221 [w,
δ(C=CPhCϵC)], 1192 (vw), 1173 (s), 1066 [w, ν(C=CC5H4) +
δ(C=CPhCϵC)], 1035 [s, δ(CHC5H4)], 914 [vw, δ(C=CPhCϵC)], 898
(m), 850 [s, γ(CHC5H4) + ρ(SiCH3)], 827 [s, ρ(SiCH3)], 805 [s,
ρ(SiCH3)], 784 [s, ρ(SiCH3)], 758 [s, γ(CHPhCϵC)], 689 [m,
γ(CHPhCϵC)], 670 [s, δ(MnCO)], 636 [s, δ(MnCO)], 605 (w), 537 [w,
[45]
δ(MnCO)] cm–1
.
UV/Vis (hexane): λ (ε) = 214 [40000,
C5H4Mn(CO)3], 238 (34000, PhCϵC), 248 (43000, PhCϵC), 260
(33000, PhCϵC), 332 [br., 1600, C5H4Mn(CO)3] nm
(Lmol–1 cm–1).[41]
Supporting Information (see footnote on the first page of this arti-
cle): Figure 1 and Figure 2 in color; tables of bond lengths and
angles of compound 1.
(b) Synthesis via Thallium [Dimethyl(phenylethynyl)silyl]cyclopenta-
dienide
TlCl (500 mg, 2.08 mmol) and LiC5H4SiMe2CϵCPh (461 mg,
2.00 mmol) were stirred in THF (15 mL) at room temperature. The
lithium salt immediately dissolved. After 1 d, the TlCl had also
disappeared, and nacreous, light grey flakes had formed instead.
After 2 d, the solvent was evaporated in vacuo, which left a mixture
of the thallium salt and LiCl as a light brown solid. Solubility:
THF; sparingly in benzene. 1H NMR (THF): δ = 7.40 (m, 2 H,
Phortho), 7.25 (m, 3 H, Phmeta+para), 6.06 (m/br, 2 H, C5H4), 5.92 (m/
br, 2 H, C5H4), 0.32 (s, 6 H, SiMe2) ppm. 13C NMR (THF): δ =
132.5 (s, 2 C, Phortho), 128.8 (s, 2 C, Phmeta), 128.7 (s, 1 C, Phpara),
125.0 (s, 1 C, Phipso), 115.9 (s, 2 C, CHCp), 113.3 (s, 1 C, CCp), 111.7
Acknowledgments
The authors thank the Deutsche Forschungsgemeinschaft and the
Fonds der Chemischen Industrie for financial support.
[1] F. Hoffmann, J. Wagler, U. Böhme, G. Roewer, J. Organomet.
Chem. 2012, 705, 59–69.
[2] 93 compounds (March 2012), selected references: a) W. Y.
Chan, A. Berenbaum, S. B. Clendenning, A. J. Lough, I. Man-
ners, Organometallics 2003, 22, 3796–3808; b) S. Welfelé, N.
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[3] a) S. Arndt, T. P. Spaniol, J. Okuda, Organometallics 2003, 22,
775–781; b) J. Hitzbleck, J. Okuda, Organometallics 2007, 26,
3227–3235.
(s, 2 C, CHCp), 105.4 (s, 1 C, CϵC–Si), 97.6 (s, 1 C, CϵC–Si), 1.5
1
(s, 2 C, SiMe2) ppm. 29Si NMR (THF): δ = –29.8 [s, JSiC(Me)
=
1
1
57 Hz (2 C), JSiC(C5H4) = 81 Hz (1 C), JSiC(CϵC) = 85 Hz (1 C),
2JSiC(CϵC) = 16 Hz (1 C)] ppm.
The prepared thallium compound was stirred with Mn(CO)5Cl
(465 mg, 2.02 mmol) in benzene (20 mL) at room temperature, and
a weak gas evolution commenced. After 1 d, the solution was
heated to reflux for 3 h, and the solvents were evaporated in vacuo
after cooling to room temperature. The residue was extracted with
hexane (4ϫ 5 mL), the extracts were combined, and the solvent
was evaporated in vacuo. The remaining residue was sublimated in
vacuo, which yielded an orange-brown oil (600 mg, 83 % crude
yield). The sublimate consisted of Mn2(CO)10 and CpMn(CO)3.
The oil was “recrystallized” twice from hexane (2–3 mL) at –78 °C,
which afforded the product as an orange-brown solid. It is air-
stable for some time but should be stored under argon in a refriger-
ator.
[4] P. Chadha, J. L. Dutton, P. J. Ragogna, Can. J. Chem. 2010, 88,
1213–1221.
[5] L. P. Asatiani, D. S. Zurabishvili, I. M. Gverdtsiteli, Zh.
Obshch. Khim. 1978, 48, 2386–2387.
[6] Selected references: a) E. B. Sokolova, S. M. Massarskaya,
N. A. Varfolomeeva, Zh. Obshch. Khim. 1970, 40, 1762–1766;
b) B. Garcia, C. M. Casado, I. Cuadrado, B. Alonso, M. Mo-
ran, J. Losada, Organometallics 1999, 18, 2349–2356; c) L. P.
Asatiani, A. A. El-Agamy, Zh. Obshch. Khim. 1980, 50, 1584–
1589; d) L. Lukesova, P. Stepnicka, K. Fejfarova, R. Gyepes,
I. Cisarova, M. Horacek, J. Kubista, K. Mach, Organometallics
2002, 21, 2639–2653; e) D. Seyferth, R. Wyrwa, U. W. Franz,
S. Becke, WO 9732908 A1 19970912; f) D. Seyferth, R. Wyrwa,
WO 9732918 A2 19970912; g) D. Seyferth, R. Wyrwa, US
5969073 A 19991019; h) E. Ihara, M. Tanaka, H. Yasuda, T.
Maruo, N. Kanehisa, Y. Kai, Kidorui 1999, 34, 32–33; i) E.
Ihara, M. Tanaka, H. Yasuda, N. Kanehisa, T. Maruo, Y. Kai,
J. Organomet. Chem. 2000, 613, 26–32; j) W. J. Evans, J. C.
Brady, J. W. Ziller, J. Am. Chem. Soc. 2001, 123, 7711–7712.
[7] F. Hoffmann, J. Wagler, G. Roewer, “Transition Metal Alkynyl
Silyl Complexes”, Poster P033, 14th International Symposium
on Organosilicon Chemistry / 3rd European Organosilicon
Days, Würzburg, July 31–August 5, 2005, Book of Abstracts,
p. 139.
[8] a) Ng. Hao, B. G. Sayer, G. Denes, D. G. Bickley, C. Detellier,
M. J. McGlinchey, J. Magn. Reson. 1982, 50, 50–63; b) A. Dor-
mond, M. Fauconet, J. C. Leblanc, C. Moise, Polyhedron 1984,
3, 897–900.
[9] All average values are search results from the Cambridge Struc-
tural Database (CSD) of the CCDC.
[10] a) B. J. Grimmond, J. Y. Corey, N. P. Rath, Acta Crystallogr.,
Sect. C 2000, 56, 53–55; b) R. Wolfgramm, C. Ramos, P. Royo,
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Acta 2003, 347, 114–122; c) O. V. Starovskii, Yu. T. Struchkov,
Dokl. Akad. Nauk SSSR 1960, 135, 620–623; d) V. V. Tkachev,
L. O. Atovmyan, Zh. Strukt. Khim. 1972, 13, 287–290; e) A.
Yield: 420 mg, 1.16 mmol, 58%. M.p. 20–22 °C (argon), 18–19 °C
(air). Solubility: hexane, toluene, diethyl ether, THF, chloroform.
C18H15MnO3Si (362.339): calcd. C 59.67, H 4.17; found C 60.02,
H 4.06. 1H NMR (0.58 mol L–1 in CDCl3): δ = 7.48 (m, 2 H,
3/4
Phortho), 7.30 (m, 3 H, Phmeta+para), 4.98 (“t”,
J
HH
= 1.8 Hz, 2 H,
3/4
1
C5H4), 4.80 (“t”,
J
HH
= 1.8 Hz, 2 H, C5H4), 0.45 (s, JHC =
120 Hz, 6 H, SiMe2) ppm. 13C NMR (0.58 molL–1 in CDCl3): δ =
224.8 (br., Δν1/2 = 22 Hz, CO), 132.1 (s, 2 C, Phortho), 128.9 (s, 1 C,
2
Phpara), 128.3 (s, 2 C, Phmeta), 122.6 (s, 1 C, Phipso), 107.0 (s, JCSi
= 17 Hz, 1 C, CϵC–Si), 91.9 (s, 2 C, C5H4), 90.9 (s, 1JCSi = 92 Hz,
1
1 C, CϵC–Si), 84.3 (s, 2 C, C5H4), 84.2 (s, JCSi = 73 Hz, 1 C,
C5H4), –0.1 (s, JCSi = 59 Hz, 2 C, SiMe2) ppm. 29Si NMR
1
(0.58 molL–1 in CDCl3): δ = –23.2 [s (1H coupled: sept, JSiH
=
2
1
1
6.8 Hz), JSiC(Me) = 59 Hz (2 C), JSiC(C5H4) = 74 Hz (1 C),
1JSiC(CϵC) = 92 Hz (1 C), JSiC(CϵC) = 18 Hz (1 C)] ppm. 55Mn
2
NMR (0.58 molL–1 in CDCl3): δ = –2140 (Δν1/2 = 23 kHz) ppm.
IR (hexane): ν = 2161 [w, ν(CϵC)], 2024 [s, ν(CϵO)], 1944 [vs,
˜
ν(CϵO)] cm–1. IR (neat liquid): ν = 3099 [vw, ν(CHCp/Ph)], 3081
˜
[w, ν(CHCp/Ph)], 3056 [vw, ν(CHCp/Ph)], 2961 [m, νas(CH3)], 2897
[vw, νs(CH3)], 2158 [s, ν(CϵC)], 2018 [vs, ν(CϵO)], 1930 [vs,
6024
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© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2012, 6018–6026

Cyclopentadienyl–Transition-Metal Complexes with Alkynylsilyl Groups
Clearfield, D. K. Warner, C. H. Saldarriaga-Molina, R. Ropal,
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FULL PAPER
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Received: June 28, 2012
Published Online: October 17, 2012
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© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2012, 6018–6026