Zirconium and hafnium complexes with (allylsilyl)(η-amidosilyl)- η5-cyclopentadienyl ligands: Synthesis, structure and reactivity

Article abstract of DOI:10.1002/ejic.200500379

The disubstituted cyclopentadiene C₅H₄(SiMe ₂Cl)[SiMe₂(CH₂CH=CH₂)] was isolated by reaction of the lithium salt [Li{C₅H₄SiMe ₂(CH₂CH=CH₂)}] with SiMe₂Cl ₂. It was then treated with NH₂tBu and LiNH(2,6-Me ₂C₆H₃) to give the (aminosilyl)cyclopentadienes C₅H₄[SiMe₂(CH₂CH=CH ₂)][SiMe₂(NHR)], which were further deprotonated to their dilithium salts [Li₂{1-SiMe₂NR-3-SiMe₂(CH ₂CH=CH₂)C₅H₃}] (R = tBu, 2,6-Me ₂C₆H₃). Reactions of the metal halides ZrCl₄(THF)₂ and HfCl₄ with these dilithium salts, followed by alkylation of the resulting dichloro complexes, afforded the (η¹-amidosilyl)-η⁵-cyclopentadienyl complexes [M{η⁵-C₅H₃(SiMe₂- η¹-NR)[SiMe₂(CH₂CH=CH₂)]}X ₂] (R = tBu, 2,6-Me₂C₆H₃; X = Cl, Me, CH₂Ph; M = Zr, Hf). Only the bis(iminoacyl) complexes [M{η⁵-C₅H₃(SiMe₂- η¹-NtBu)[SiMe₂(CH₂CH=CH₂)]} {η²-CR=N(2,6-Me₂C₆H₃)} ₂] (M = Zr, Hf; R = Me, CH₂Ph) could be isolated when the dialkylzirconium and -hafnium complexes were treated with CN(2,6-Me ₂C₆H₃); these were slowly transformed into the C-C-coupled diazametallacyclopentene compounds [M{η⁵-C ₅H₃ (SiMe₂-η¹-NtBu) [SiMe ₂(CH₂CH=CH₂)]}{η¹-N(2,6-Me ₂C₆H₃)-CR=CR-η¹-N(2,6-Me ₂C₆H₃)}] (R = Me, CH₂Ph, M = Zr; R = Me, M = Hf) when their toluene solutions were heated to 70°C-80°C for long periods (2-4 d). The structural characterisation of all of the new compounds is described and the molecular structure of the dimeric dichlorozirconocene [ZrCl(μ-Cl){η⁵-C₅H ₃(SiMe₂-η¹-NtBu)[SiMe₂(CH ₂CH=CH₂)]}]₂, was determined by X-ray diffraction methods. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.

Full text of DOI:10.1002/ejic.200500379

FULL PAPER
Zirconium and Hafnium Complexes with (Allylsilyl)(η-amidosilyl)-η5-
cyclopentadienyl Ligands: Synthesis, Structure and Reactivity
Cristina Ramos,[a] Pascual Royo,*[a] Maurizio Lanfranchi,[b] Maria Angela Pellinghelli,[b]
and Antonio Tiripicchio[b]
Keywords: Insertion / Isocyanides / Hafnium / Metallocenes / Zirconium
The disubstituted cyclopentadiene C5H4(SiMe2Cl)[Si-
Me2(CH2CH=CH2)] was isolated by reaction of the lithium
salt [Li{C5H4SiMe2(CH2CH=CH2)}] with SiMe2Cl2. It was
then treated with NH2tBu and LiNH(2,6-Me2C6H3) to give
the (aminosilyl)cyclopentadienes C5H4[SiMe2(CH2CH=CH2)]-
[SiMe2(NHR)], which were further deprotonated to their di-
lithium salts [Li2{1-SiMe2NR-3-SiMe2(CH2CH=CH2)C5H3}]
(R = tBu, 2,6-Me2C6H3). Reactions of the metal halides
ZrCl4(THF)2 and HfCl4 with these dilithium salts, followed
by alkylation of the resulting dichloro complexes, afforded
the (η1-amidosilyl)-η5-cyclopentadienyl complexes [M{η5-
C5H3(SiMe2-η1-NR)[SiMe2(CH2CH=CH2)]}X2] (R = tBu, 2,6-
Me2C6H3; X = Cl, Me, CH2Ph; M = Zr, Hf). Only the bis(imi-
Me, CH2Ph) could be isolated when the dialkylzirconium
and -hafnium complexes were treated with CN(2,6-
Me2C6H3); these were slowly transformed into the C–C-cou-
pled diazametallacyclopentene compounds [M{η5-C5H3
(SiMe2 -η1 -NtBu)[SiMe2 (CH2 CH=CH2 )]}{η1 -N(2,6-
Me2C6H3)-CR=CR-η1-N(2,6-Me2C6H3)}] (R = Me, CH2Ph, M
= Zr; R = Me, M = Hf) when their toluene solutions were
heated to 70 °C–80 °C for long periods (2–4 d). The structural
characterisation of all of the new compounds is described
and the molecular structure of the dimeric dichlorozir-
conocene [ZrCl(µ-Cl){η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2-
CH=CH2)]}]2, was determined by X-ray diffraction methods.
noacyl)
complexes
[M{η5-C5H3(SiMe2-η1-NtBu)[SiMe2-
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
(CH2CH=CH2)]}{η2-CR=N(2,6-Me2C6H3)}2] (M = Zr, Hf; R =
group 4 metal complexes of the type represented in
Scheme 1. These compounds are described in this paper,
along with the insertion reactions of isocyanides into their
metal–alkyl bonds and C–C coupling reactions of the re-
sulting iminoacyl derivatives.
Introduction
Many reports[1–9] have described the dynamics of the ion
pairs formed by activation of a precursor metallocene with
various Lewis acids, which are assumed to be the species
responsible for the metallocene-catalysed alkene polymeri-
sation[5,10–15] and considered to be the cornerstone of its
efficiency and stereocontrol. Several strategies have been
used to stabilize the intermediate cationic alkyl alkene me-
tallocene[10,16–21]
and
(η1-amidosilyl)-η5-cyclopen-
tadienyl[3,22–30] d0 group-4 metal complexes. We have re-
ported[31,32] the formation of alkyl alkene metallocene cat-
ions through η2-coordination of the alkene moiety of an
allylsilyl group tethered to the cyclopentadienyl ring. In or-
der to study the formation and reactivity of the correspond-
ing (η1-amidosilyl)-η5-cyclopentadienyl cationic com-
pounds reported elsewhere, we synthesised and character-
ised disubstituted (allylsilyl)(amidosilyl)cyclopentadienyl
Scheme 1.
Results and Discussion
Successful synthesis of the disubstituted cyclopentadiene
containing the two required aminosilyl [SiMe2(NHtBu)]
and allylsilyl [SiMe2(CH2CH=CH2)] functionalities was
achieved by first introducing the allylsilyl group[33] followed
by metallation and reaction of the resulting lithium (allylsi-
lyl)cyclopentadienide salt[31,32] with SiMe2Cl2 to give the di-
silylated cyclopentadiene C5H4(SiMe2Cl)[SiMe2(CH2CH=
CH2)] (1, Scheme 2), which was isolated as a yellow liquid.
[a] Departamento de Química Inorgánica, Universidad de Alcalá,
Campus Universitario,
28871 Alcalá de Henares, Spain
Fax: +34-91-885-4683
E-mail: pascual.royo@uah.es
[b] Dipartamento di Chimica Generale ed Inorganica, Chimica
Analitica, Chimica Fisica, Università di Parma,
Parco Area delle Scienze 17/A, 43100 Parma, Italy
Fax: +39-0521-905-557
E-mail: maurizio.lanfranchi@unipr.it
3962
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejic.200500379
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Zr and Hf Complexes with (Allylsilyl)(η-amidosilyl)cyclopentadienyl Ligands
FULL PAPER
Scheme 2.
Further aminolysis of the chorosilyl derivative 1 by reac-
tion with the primary amine NH2tBu or metathesis with
LiNH(2,6-Me2C6H3) afforded the disilylated cyclopentadi-
enes C5H4[SiMe2(CH2CH=CH2)][SiMe2(NHR)] (R = tBu
2, 2,6-Me2C6H3 3), which were isolated as oily yellow and
Scheme 3.
orange liquids, respectively. The chlorosilyl derivative 1 was spectra of all the complexes show the typical pattern of the
identified by 1H NMR spectroscopy as a unique 1,1-isomer. allyl substituent, which consists of one high-field multiplet
However, formation of the 1,3-isomer is favoured for the for the SiCH2 protons at δ = 1.7–1.8 ppm, one multiplet at
aminosilyl compounds 2 and 3 due to the presence of the δ = 5.6–5.8 ppm for the internal olefinic proton and one
sterically more demanding amino substituents (see Exp. multiplet for the two external olefinic protons at δ = 4.8–
Sect.).
4.9 ppm. The ring Cipso resonance for compounds 6–9 ap-
The mixture of isomers of the disilylcyclopentadienes 2 pears at higher field than those of the other carbon atoms,
and 3 was metallated by treatment with 2 equiv. of nBuLi to consistent with the (amidosilyl)cyclopentadienyl ligands
give the dilithium salts, which were isolated as white solids adopting a chelate coordination mode with the metal cen-
containing one single component and were identified by 1H tre.[35] This NMR behaviour may suggest the presence of
NMR spectroscopy as the 1,3-isomer [Li2{1-SiMe2NR-3- mononuclear structures of the silylamido derivatives 6–9 in
SiMe2(CH2CH=CH2)C5H3}] (R = tBu 4, 2,6-Me2C6H3 5). solution, for which the enantiotopic 1,3-disilylcyclopentadi-
1
Their H NMR spectra show the three ring-proton signals enyl ring faces are responsible for the asymmetry of these
expected for an asymmetric molecule, whereas the dia- molecules. However, it could also be consistent with a cen-
stereotopic methyl groups of both silyl fragments and the trosymmetric dimeric diastereoisomer with two equivalent
diastereotopic methylene protons of the allylsilyl fragment Cp-silylamido systems, which is formed by two mononu-
are observed as two singlets (see Exp. Sect.).
clear units held together by a pair of bridging chloro li-
A direct synthesis based on halide metathesis, when the gands. Both mono- and dinuclear structures exhibit two
metal tetrahalides were treated with 1 equiv. of the dilith- non-equivalent chloro ligands, one of which is localised un-
ium salts 4 and 5, was used to transfer the (amidosilyl)cy- der the allyldimethylsilyl substituent of the cyclopentadienyl
clopentadienyl ligand, as shown in Scheme 3. Reaction of 4 ligand in the mononuclear structure or is the terminal li-
with ZrCl4(THF)2 or HfCl4 in toluene at room temperature gand in the dinuclear compound.
yielded the “constrained-geometry” complexes [MCl(µ-Cl)-
The dimeric structure of complex 6 in the solid state was
{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}]2 (M = determined by X-ray diffraction methods on a single crystal
Zr 6, Hf 7), which were isolated in high yield as a yellow obtained from a hexane solution cooled to –35 °C. The
crystalline solid (6) and an oily orange solid (7) and charac- same dimeric structure may be tentatively assigned to all
terised by elemental analysis (6), NMR spectroscopy and of the other complexes 7–9 in the solid state, as shown in
X-ray diffraction methods (6). Analogous reactions using Scheme 3. Typical signals due to coordinated THF were ob-
the dilithium salt of the corresponding (2,6-dimethylphenyl) served in the H and 13C NMR spectra of the more elec-
1
amido ligand 5 were carried out in the hope of obtaining tron-deficient complex 8 containing the less basic amido li-
improved crystallinity of the resulting metal compounds.[34] gand.
However, the new dichloro complexes [MCl(µ-Cl){η5-
A view of the molecular structure of complex 6, together
C5H3[SiMe2-η1-N(2,6-Me2C6H3)][SiMe2(CH2CH=CH2)]}]2 with the atomic labelling scheme, is shown in Figure 1. Se-
(M = Zr 8, Hf 9) were always obtained as oily orange and lected bond lengths and angles are given in Table 1. The
white solid products, respectively, which easily decomposed crystal structure consists of discrete chloro-bridged centro-
with elimination of free amine; consequently, they were dif- symmetric
dimeric
molecules
of
[ZrCl(µ-Cl){η5-
ficult to purify, giving rather low yields (lower than 30%) C5H3(SiMe2-η1-NtBu)[SiMe2CH2CH=CH2]}]2. Each zirco-
after purification. These compounds were not studied fur- nium atom is bound to the cyclopentadienyl ring in a
ther.
slightly asymmetric fashion [Zr–C bond lengths are in the
1
The H and 13C NMR spectra of the silylamido deriva- range 2.441(6)–2.557(7) Å, while the Zr–CT distance is
tives 6–9 show three multiplets (1H) and five resonances 2.187(8) Å, where CT is the centroid of the ring], to the
(13C) for the Cp ring protons and carbon atoms and four nitrogen atom of the silylamido moiety [Zr–N
=
singlets (1H and 13C) for the two diastereotopic silylmethyl 2.042(6) Å], to a terminal chlorine atom [Zr–Cl2 =
groups; two of the multiplets were occasionally observed as 2.457(2) Å] and to two bridging chlorine atoms [Zr–Cl1 =
overlapped signals in the 1H NMR spectrum. The 1H NMR 2.645(2) and Zr–Cl1Ј = 2.653(2) Å]. The Zr atom is in a
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C. Ramos, P. Royo, M. Lanfranchi, M. A. Pellinghelli, A. Tiripicchio
FULL PAPER
four-legged piano-stool arrangement if the centroid of the Table 1. Selected bond lengths [Å] and angles [°] for compound 6.
cyclopentadienyl ring is taken into consideration. The value
Zr–Cl(1)
Zr–Cl(1)Ј
Zr–Cl(2)
Zr–N
Zr–CT
C(1)–C(2)
C(2)–C(3)
C(3)–C(4)
Cl(1)–Zr–Cl(1)Ј
Cl(2)–Zr–Cl(1)
Cl(2)–Zr–Cl(1)Ј
Cl(1)–Zr–CT[a]
Cl(2)–Zr–CT[a]
Si(1)–N–Zr
C(8)–N–Si(1)
2.645(2)
2.653(2)
2.457(2)
2.042(6)
2.187(8)
1.418(10)
1.416(10)
1.411(10)
72.26(7)
80.76(7)
145.37(7)
120.4(2)
107.9(2)
108.1(3)
128.9(5)
C(4)–C(5)
C(1)–C(5)
C(1)–Si(1)
Si(1)–N
N–C(8)
C(4)–Si(2)
Si(2)–C(14)
1.447(10)
1.393(10)
1.872(9)
1.743(5)
1.492(9)
1.890(9)
1.894(10)
of the Zr–N bond length is consistent with double-bond
character and falls in the range (2.034–2.088 Å) retrieved
from the Cambridge Structural Database files for pentaco-
ordinate Zr complexes containing the ZrClCpSiN(amido)
moiety.[36–45] The almost equal bridging Zr–Cl distances are
significantly longer than the terminal Zr–Cl distance, and
this last bond length again falls in the range 2.432–2.529 Å
retrieved from the CSD files for similar complexes. To the
best of our knowledge, the only chloro-bridged dimeric zir-
conium complex found in the literature containing a (ami-
dosilyl)cyclopentadienyl moiety is (R,R)-[ZrCl(µ-Cl)]
{η5:η1-C5Me4SiMe2NCH(Me)(Ph)}2,[39] where the Zr–Cl
N–Zr–Cl(2)
N–Zr–Cl(1)
N–Zr–Cl(1)Ј
N–Zr–CT
CT–Zr–Cl(1)Ј
C(8)–N–Zr
96.6(2)
138.2(2)
89.6(2)
100.3(3)
104.4(2)
123.0(4)
bridging bond lengths are significantly different. The trans [a] CT is the centroid of the C(1)···C(5) cyclopentadienyl ring. Sym-
metry transformation used to generate equivalent atoms: –x, –y,
–z + 2.
influence of the amido nitrogen and chlorine coordinating
atoms seem similar in 6, and the bridging Zr–Cl bond
lengths are not significantly different.
R = Me 10, CH2Ph 11; M = Hf, R = Me 12, CH2Ph 13),
which were isolated as brown and orange oily solids, respec-
tively, and identified by elemental analysis and NMR spec-
troscopy. In addition to the same features discussed above
for the precursor dichloro complexes, the non-equivalency
of the two alkyl groups of these asymmetric molecules is
easily demonstrated by their 1H and 13C NMR spectra. The
spectra of the methyl complexes 10 and 12 show two sing-
lets (1H) and two resonances (13C) for the two non-equiva-
lent, metal-bonded methyl groups, whereas four doublets
(1H) for the two diastereotopic methylene protons and two
resonances (13C) for the methylene carbon atom are ob-
served for each non-equivalent, metal-bonded benzyl group
of the benzyl derivatives 11 and 13.
Figure 1. ORTEP drawing of the molecular structure of 6 in the
solid state; thermal ellipsoids are drawn at the 30% probability
level.
The C1 atom that bears the amidosilyl arm is pyrami- Scheme 4.
dally distorted, as shown by the sum of bond angles
(350.8°) as in the other chloro(amidosilyl)cyclopentadienyl
Insertion of isocyanide into one of the two non-equiva-
complexes,[36–45] and in the doubly silylamido-bridged cy- lent metal–alkyl bonds of these dialkyl compounds may af-
clopentadienyltitanium complex,[46] while the C4 atom that ford mixtures of two diastereomers, unless for diastereo-
bears the allylsilyl arm is weakly pyramidally distorted (the selective reactions.[47] However, when 1 equiv. of CN(2,6-
sum of the bond angles is 359.3°). The Si1 and Si2 atoms Me2C6H3) was added to the toluene solutions of the dialk-
are out of the Cp plane by –0.845(2) and 0.250(3) Å, respec- yl(amidosilyl)cyclopentadienyl compounds 10–13, the ini-
tively.
tially formed 16-electron iminoacyl compounds could not
In spite of having non-equivalent chloro ligands, none of be detected by NMR spectroscopy because they react very
these zirconium and hafnium complexes showed selective easily to give the bis(iminoacyl) complexes by further inser-
reactions when they were treated with alkylating agents. As tion into the second metal–alkyl bond. This behaviour is in
shown in Scheme 4, reactions of complexes 6 and 7 with contrast to that observed for metallocene-type complexes
2 equiv. of MgClR (R = Me, CH2Ph) in hexane at room for which the monoiminoacyl complexes are 18-electron
temperature gave the dialkyl complexes [M{η5- species, which do not undergo further insertion into the sec-
C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}R2] (M = Zr, ond metal–alkyl bond.
3964
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Zr and Hf Complexes with (Allylsilyl)(η-amidosilyl)cyclopentadienyl Ligands
FULL PAPER
Therefore these insertion reactions were complete when to those observed for the starting bis(iminoacyl) com-
toluene solutions of the dialkyl complexes 10–13 were pounds, whereas the 13C NMR signals due to the enediam-
treated with two equivalents of 2,6-xylyl isocyanide at room ido sp2-carbon atoms are observed at δ = 111–112 ppm.
temperature to give the corresponding bis(iminoacyl) com-
pounds[48] [M{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
CH2)]}{η2-CR=N(2,6-Me2C6H3)}2] (M = Zr, R = Me 14, Conclusions
CH2Ph 15; M = Hf, R = Me 16, CH2Ph 17) which were
isolated as red and orange oily products and identified by
elemental analysis and NMR and infrared spectroscopy.
Dichloro- and dialkyl(amidosilyl)cyclopentadienyl zirco-
nium and -hafnium complexes of the type [M{η5-C5H3[Si-
Me2(CH2CH=CH2)](SiMe2-η-NR)}X2] with the allyldime-
thylsilyl-substituted cyclopentadienyl ligand have been iso-
lated in high yields by conventional synthetic methods and
characterised by NMR spectroscopy and X-ray diffraction
As shown in Scheme 5 the bis(iminoacyl) complexes 14–
16 were slowly converted into the C–C-coupled com-
pounds.[49] This transformation was complete when their
toluene solutions were heated at 70 °C–80 °C for long
methods.
periods (2 d for 18 and 19 and 4 d for 20) in sealed tubes
The two non-equivalent chloro and alkyl ligands of these
asymmetric molecules do not show diastereoselective reac-
tions, so that alkylation of the dichloro complexes only
gives dialkyl derivatives, and insertion of CN(2,6-Me2C6H3)
to give the diazametallacyclopentene complexes [M{η5-
C5 H3 (SiMe2 -η-NtBu)[SiM e2 (C H2 CH =C H2 )] }-
{η-N(2,6-Me2C6H3)CR=CR-η-N(2,6-Me2C6H3)] (R = Me,
M = Zr 18, Hf 19; R = CH2Ph, M = Zr 20). Complexes
into the metal–alkyl bonds only afforded bis(iminoacyl)
18–20 were isolated as red (18) and brown (19, 20) oily pro-
compounds. Formation of monoalkyl and monoiminoacyl
ducts and identified by NMR and IR spectroscopy. The 1H
complexes could not be detected in any of these reactions.
and 13C NMR spectra of all of these iminoacyl (14–17) and
NMR spectroscopic studies revealed that the iminoacyl li-
enediamido (18–20) compounds correspond to the asym-
metric molecules expected from the enantiotopic character
of the disilylcyclopentadienyl ligand (see Exp. Sect.). The
presence of four methyl resonances (occasionally over-
lapped) for the [(2,6-dimethylphenyl)imino]acyl groups indi-
cates that rotation around the N–aryl bond is avoided.
gand is η2-coordinated in all of these compounds with the
nitrogen atom always occupying the internal coordination
site. C–C coupling reactions between the two iminoacyl li-
gands are very slow processes that give quantitative yields
of the diazametallacyclopentene complexes after heating
the toluene solutions of the bis(iminoacyl) complexes at 70–
80 °C for 2–4 d.
Experimental Section
General Considerations: All manipulations were performed under
argon using standard Schlenk and high-vacuum line techniques or
a glovebox model MO40-2. Solvents were pre-dried and purified
by distillation under argon from an appropriate drying agent (so-
dium for toluene, sodium/potassium alloy for hexane and sodium/
benzophenone for diethyl ether and THF) before use. Deuterated
Scheme 5.
solvents were stored over activated molecular sieves (4 Å) in Teflon-
valved flasks and previously degassed by several freeze-pump-thaw
cycles. NH2tBu (Aldrich) was dried with sodium and distilled prior
to use. SiMe2(CH2CH=CH2)Cl (Aldrich), SiMe2Cl2 (Aldrich),
Compounds 14–17 contain the iminoacyl ligand η2-coor-
dinated to the metal centre as shown by their spectroscopic
1
data. The signals observed in the H NMR spectra for the
alkyl and methylene(benzyl) groups migrated to the inserted
aryl isocyanide are shifted downfield (by about 2 ppm) with
respect to the values observed for the metal-bonded groups
of the precursor dialkyl complexes. In contrast, the 13C
NMR resonance of the alkyl carbon atom is shifted to
higher field (by about 10 ppm for Zr and 20 ppm Hf) on
insertion. The most remarkable feature observed in the
NMR spectra of these complexes is the chemical shift of
the resonance due to the iminoacyl carbon atoms, which is
shifted downfield at δ = 250–268 ppm. Another important
spectroscopic feature that allows the assignment of the imi-
noacyl coordination mode in solution is the stretching
ν(C=N) frequency of the iminoacyl bond observed in the
IR spectra at 1540–1555 cm–1, which corresponds to the η2-
coordinated iminoacyl ligands.[50] The 1H NMR resonances
due to the migrated alkyl groups in the C–C coupled enedi-
nBuLi (Aldrich), HfCl4 (Merck), MgClMe (Aldrich) and
MgCl(CH2Ph) (Aldrich) were purchased from commercial sources
and
used
without
further
purification.
C5H5[Si-
Me2(CH2CH=CH2)],[51] [Li{C5H4SiMe2(CH2CH=CH2)},[51] and
[52]
ZrCl4(THF)2
were prepared according to literature procedures.
C, H and N microanalyses were performed with a Perkin–Elmer
240B. Unreliable elemental analytical data are not given for some
highly soluble and air-sensitive compounds which could not be
crystallised and were isolated as spectroscopically pure oily pro-
ducts. NMR spectra, measured at 25 °C, were recorded with a Var-
ian Unity 300 (1H NMR at 300 MHz and 13C NMR at 75 MHz)
spectrometer. 1H and 13C chemical shifts are reported in δ units
relative to TMS standard.
Synthesis of C5H4(SiMe2Cl)[SiMe2(CH2CH=CH2)] (1): SiMe2Cl2
(5.7 mL, 47 mmol) was added to a THF (100 mL) solution of
[Li{η5-C5H4SiMe2(CH2CH=CH2)}] (8.0 g, 47 mmol), cooled to
–78 °C and the mixture was stirred at room temperature for 16 h.
amido complexes 18–20 are shifted downfield with respect The solvent was then removed under vacuum and the residue was
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C. Ramos, P. Royo, M. Lanfranchi, M. A. Pellinghelli, A. Tiripicchio
FULL PAPER
extracted into hexane (2×50 mL). After filtration and evaporation
of the solvent under reduced pressure, compound 1 was isolated as
a yellow liquid (9.81 g, 38.18 mmol, 82% yield). C12H21ClSi2
(256.92): calcd. C 56.10, H 8.24; found C 55.88, H 8.36. H NMR
(300 MHz, CDCl3, 25 °C): δ = 0.05 (s, 6 H, SiMe2), 0.23 (s, 6 H,
Synthesis of [Li2{1-SiMe2N(2,6-Me2C6H3)-3-SiMe2(CH2CH=CH2)-
C5H3} (5): A suspension of 3 (14 g, 41 mmol) in diethyl ether was
treated at –78 °C with a 1.6  hexane solution of nBuLi (51 mL,
82 mmol). The mixture was stirred at room temperature for 4 h and
the solvent was then removed under vacuum to give a yellow solid
1
SiMe2), 1.47 (d, J = 8.1 Hz, 2 H, SiCH2), 4.86 (m, 2 H, CH=CH2), which, after being washed with hexane (2×50 mL) and dried under
5.65 (m, 1 H, CH=CH2), 6.57 (m, 2 H, C5H4), 6.81 (m, 2 H, C5H4) vacuum, was identified as the dilithium salt 5 (13 g, 36.9 mmol,
ppm. 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ = –2.9 (SiMe2), 90% yield). C20H29Li2NSi2 (353.51): calcd. C 67.95, H 8.27, N 3.96;
1.5 (SiMe2), 22.8 (SiCH2), 58.3 (C5H4, Cipso), 113.9 (CH=CH2), found C 67.18, H 8.02, N 3.95. 1H NMR (300 MHz, C6D6, 25 °C):
133.1 (C5H4), 134.6 (C5H4), 134.9 (CH=CH2) ppm. 1H NMR δ = 0.32 (s, 6 H, SiMe2), 0.57 (s, 6 H, SiMe2), 1.85 (m, 2 H, SiCH2),
(300 MHz, C6D6, 25 °C): δ = 0.04 (s, 6 H, SiMe2), 0.10 (s, 6 H,
2.75 (s, 6 H, C6H3 Me2), 4.90 (m, 2 H, CH=CH2), 6.05 (m, 1 H,
SiMe2), 1.47 (d, J = 8.1 Hz, 2 H, SiCH2), 4.86 (m, 2 H, CH=CH2), CH=CH2), 6.75–7.45 (m, C5H3 + C6H3) ppm.
5.63 (m, 1 H, CH=CH2), 6.40 (m, 2 H, C5H4), 6.64 (m, 2 H, C5H4)
Synthesis
of
[Zr{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
ppm. 13C{1H} NMR (75 MHz, C6D6, 25 °C): δ = –2.9 (SiMe2), 1.7
(SiMe2), 22.6 (SiCH2), 58.0 (C5H4, Cipso), 113.6 (CH=CH2), 132.8
(C5H4), 134.3 (C5H4), 134.7 (CH=CH2) ppm.
CH2)]}Cl2] (6): Toluene at –78 °C was added to a mixture of 4 (3 g,
9.8 mmol) and ZrCl4(THF)2 (3.7 g, 9.8 mmol) also cooled to
–78 °C. The reaction mixture was warmed to room temperature
and was stirred for 16 h. The toluene was removed under vacuum
and the residue was extracted into hexane. The solvent volume was
reduced and the solution was cooled to –40 °C to give yellow crys-
tals which were isolated by filtration (2.67 g, 5.89 mmol, 60%
yield). C16H29Cl2NSi2Zr (453.71): calcd. C 42.36, H 6.44, N 3.09;
found C 42.90, H 6.42, N 3.05. 1H NMR (300 MHz, CDCl3,
25 °C): δ = 0.33 (s, 6 H, SiMe2), 0.55 (s, 6 H, SiMe2), 1.37 (s, 9 H,
CMe3), 1.77 (m, 2 H, SiCH2), 4.86 (m, 2 H, CH=CH2), 5.74 (m, 1
H, CH=CH2), 6.44 (t, 1 H, C5H3), 6.58 (t, 1 H, C5H3), 7.02 (t, 1
H, C5H3) ppm. 13C{1H} NMR (75 MHz, CDCl3, 25 °C): δ = –3.6
(SiMe2), –3.3 (SiMe2), 0.5 (SiMe2), 0.9 (SiMe2), 23.7 (SiCH2), 32.5
(CMe3), 57.1 (CMe3), 111.9 (C5H3, Cipso), 113.7 (CH=CH2), 126.1
(C5H3), 127.1 (C5H3), 132.9 (C5H3, Cipso), 133.5 (CH=CH2) ppm.
Synthesis of C5H4[SiMe2(CH2CH=CH2)][SiMe2(NHtBu)] (2):
NH2tBu (11.5 mL, 109 mmol) was added to a solution of 1 (14 g,
54.5 mmol) in THF at –78 °C. The mixture was slowly warmed to
room temperature and stirred for 15 h. After removal of the solvent
under vacuum, the residue was extracted into hexane and the am-
monium chloride salt was removed by filtration. Product 2 was
obtained as a yellow liquid (12.48 g, 42,51 mmol, 78% yield).
C16H31NSi2 (293.60): calcd. C 65.46 H, 10.64, N 4.77; found C
1
64.44, H 10.68, N 4.48. Major isomer: H NMR (300 MHz, C6D6,
25 °C): δ = –0.14 (s, 3 H, SiMe2), –0.01 (s, 3 H, SiMe2), 0.26 (s, 3
H, SiMe2), 0.36 (s, 3 H, SiMe2), 0.60 (br. s, 1 H, NH), 1.08 (s, 9
H, CMe3), 1.45 (m, 2 H, SiCH2), 3.23 (br. s, 1 H, C5H4), 4.93 (m,
2 H, CH=CH2), 5.69 (m, 1 H, CH=CH2), 6.60, 6.81, 6.89 (m, 3 H,
C5H4) ppm. Minor isomer: 1H NMR (300 MHz, C6D6, 25 °C): δ
= 0.05 (s, 6 H, SiMe2), 0.07 (s, 6 H, SiMe2), 0.66 (br. s, 1 H, NH),
1.15 (s, 9 H, CMe3), 1.74 (m, J = 8.1 Hz, 2 H, SiCH2), 4.93 (m, 2
H, CH=CH2), 5.88 (m, 1 H, CH=CH2), 6.46, 6.72 (m, 3 H, C5H4)
ppm.
Synthesis
of
[Hf{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
CH2)]}Cl2] (7): Toluene cooled to –78 °C was added to a mixture
of 4 (1.5 g, 4.9 mmol) and HfCl4 (1.6 g, 4.9 mmol) also at –78 °C.
The reaction mixture was stirred while it was warmed to room tem-
perature. After the solution had been stirred overnight, the toluene
was removed under reduced pressure and the residue was extracted
into hexane. The solution was filtered and the solvent was removed
to give 7 as an orange oil (1.59 g, 2.95 mmol, 60% yield). 1H NMR
(300 MHz, CDCl3, 25 °C): δ = 0.32 (s, 3 H, SiMe2), 0.33 (s, 3 H,
SiMe2), 0.56 (s, 6 H, SiMe2), 1.31 (s, 9 H, CMe3), 1.77 (m, 2 H,
SiCH2), 4.89 (m, 2 H, CH=CH2), 5.77 (m, 1 H, CH=CH2), 6.35 (t,
1 H, C5H3), 6.49 (t, 1 H, C5H3), 6.97 (t, 1 H, C5H3) ppm. 13C{1H}
NMR (75 MHz, CDCl3, 25 °C): δ = –3.6 (SiMe2), –3.3 (SiMe2), 0.8
(SiMe2), 1.2 (SiMe2), 23.7 (SiCH2), 33.2 (CMe3), 55.6 (CMe3),
111.8 (C5H3, Cipso), 113.7 (CH=CH2), 124.5 (C5H3), 125.6 (C5H3),
126.0 (C5H3), 131.6 (C5H3, Cipso), 133.5 (CH=CH2) ppm.
Synthesis of C5H4[SiMe2(CH2CH=CH2)][SiMe2NH(2,6-Me26H3)]
(3): Compound 1 (13 g, 53 mmol) was added at room temperature
to a suspension of LiNH(2,6-Me2C6H3) (6.7 g, 53 mmol) in hexane
(100 ml) and the mixture was stirred for 16 h. LiCl was filtered off
and the solvent was removed from the resulting solution to give an
orange oil which was identified as 3 (14.5 g, 42.4 mmol, 80% yield).
1
Major isomer: H NMR (300 MHz, C6D6, 25 °C): δ = –0.20 (s, 3
H, SiMe2), 0.01 (s, 3 H, SiMe2), 0.14 (s, 3 H, SiMe2), 0.34 (s, 3 H,
SiMe2), 1.39 (m, 2 H, SiCH2), 2.15 (s, 6 H, C6H3 Me2), 2.54 (br. s,
1 H, NH), 3.07 (br. s, 1 H, C5H4), 4.92 (m, 2 H, CH=CH2), 5.68
(m, 1 H, CH=CH2), 6.40–7.00 (m, C5H4 + C6H3) ppm. Minor iso-
1
mer: H NMR (300 MHz, C6D6, 25 °C): δ = 0.05 (s, 3 H, SiMe2),
Synthesis of [Zr{η5-C5H3[SiMe2-η1-N(2,6-Me2C6H3)][SiMe2(CH2-
CH=CH2)]}Cl2] (8): Toluene (100 mL) was added at –78 °C to a
mixture of solid dilithium salt 5 (2 g, 5.66 mmol) and ZrCl4·2THF
(2.13 g; 5.66 mmol) and the mixture was then stirred at room tem-
0.10 (s, 3 H, SiMe2), 0.23 (s, 3 H, SiMe2), 0.28 (s, 3 H, SiMe2), 1.70
(m, 2 H, SiCH2), 2.22 (s, 6 H, C6H3 Me2), 2.54 (br. s, 1 H, NH),
2.92 (br. s, 1 H, C5H4), 4.92 (m, 2 H, CH=CH2), 5.68 (m, 1 H,
CH=CH2), 6.40–700 (m, C5H4 + C6H3) ppm.
Synthesis of [Li2{1-SiMe2NtBu-3-SiMe2(CH2CH=CH2)C5H3}] (4): perature for 16 h. After filtration of the resulting LiCl, the solvent
A 1.6  solution of nBuLi in hexane (17 ml, 28 mmol) was added
dropwise to a solution of 3 (4 g, 14 mmol) in diethyl ether at
–78 °C. The reaction mixture was warmed to room temperature
and stirred for 4 h. The solvent was removed under reduced pres-
sure to yield a solid, which was washed with hexane. The yellow
solid was dried under vacuum and was characterised as 3 (3.85 g,
12.6 mmol, 90% yield). C16H29Li2NSi2 (305.47): calcd. C 62.91, H
9.57, N 4.59; found C 62.19, H 9.78, N 4.04. H NMR (300 MHz,
C6D6, 25 °C): δ = 0.30 (s, 6 H, SiMe2), 0.46 (s, 6 H, SiMe2), 1.18
(s, 9 H, CMe3), 1.83 (m, 2 H, SiCH2), 4.89 (m, 2 H, CH=CH2),
was removed under vacuum and the residue was extracted into hex-
ane (2×50 mL). The solution was concentrated by evaporation of
the solvent under reduced pressure and cooled to –35 °C to give
compound 8 as an orange oily solid (0.91 g, 1.70 mmol, 30% yield).
1H NMR (300 MHz, CDCl3, 25 °C): δ = –0.04 (s, 3 H, SiMe2),
0.12 (s, 3 H, SiMe2), 0.38 (s, 3 H, SiMe2), 0.39 (s, 3 H, SiMe2), 1.52
(m, 2 H, SiCH2), 1.80 (t, 4 H, C2H4), 2.10 (s, 3 H, C6H3 Me2), 2.24
(s, 3 H, C6H3 Me2), 3.70 (t, 4 H, OC2H4), 4.78 (m, 2 H, CH=CH2),
5.61 (m, 1 H, CH=CH2), 6.50 (t, 1 H, C5H3), 6.77 (t, 1 H, C5H3),
6.83 (t, 1 H, C5H3), 6.70–7.00 (m, 3 H, C6H3) ppm. 13C{1H} NMR
1
6.04 (m, 1 H, CH=CH2), 6.65 (m, 1 H, C5H3), 6.80 (m, 1 H, C5H3), (75 MHz, CDCl3, 25 °C): δ = –2.7 (SiMe2), –2.6 (SiMe2), –0.4
6.90 (m, 1 H, C5H3) ppm. (SiMe2), 0.2 (SiMe2), 20.3 (C6H3 Me2), 20.6 (C6H3 Me2), 24.8
3966
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 3962–3970

Zr and Hf Complexes with (Allylsilyl)(η-amidosilyl)cyclopentadienyl Ligands
FULL PAPER
(SiCH2), 25.3 (C2H4), 68.5 (OC2H4), 113.2 (CH=CH2), 116.7 Synthesis of [Hf{η5-C5H3[SiMe2-η1-NtBu][SiMe2(CH2CH=CH2)]}-
(C5H3, Cipso), 122.4 (C5H3), 124.2 (C5H3), 127.8 (C5H3), 127.8, Me2] (12): A 3  THF solution of MgClMe (2.9 mL, 8.8 mmol)
129.8, 130.0, 130.7, 132.4 (C6H3), 134.2 (C5H3, Cipso), 134.9
(CH=CH2), 151.2 (C6H3, Cipso) ppm.
was added at –78 °C to a solution of the dichloro complex 7 (2.4 g,
4.4 mmol) in hexane. The reaction mixture was stirred for 16 h
while it was warmed slowly to room temp. The solution was filtered
and the solvent removed under reduced pressure to give complex
12 as an orange oil (1.32 g, 2.64 mmol, 60% yield). C18H35HfNSi2
(500.14): calcd. C 43.23, H 7.05, N 2.80; found C 43.09, H 7.51, N
2.67. 1H NMR (300 MHz, C6D6, 25 °C): δ = 0.00 (s, 3 H, HfMe2),
0.03 (s, 3 H, HfMe2), 0.24 (s, 3 H, SiMe2), 0.26 (s, 3 H, SiMe2),
0.38 (s, 6 H, SiMe2), 1.32 (s, 9 H, CMe3), 1.68 (m, 2 H, SiCH2),
4.91 (m, 2 H, CH=CH2), 5.78 (m, 1 H, CH=CH2), 6.20 (t, 1 H,
C5H3), 6.27 (t, 1 H, C5H3), 6.67 (t, 1 H, C5H3) ppm. 13C{1H} NMR
(75 MHz, C6D6, 25 °C): δ = –2.6 (SiMe2), –2.4 (SiMe2), 2.0
(SiMe2), 2.4 (SiMe2), 25.2 (SiCH2), 35.1 (CMe3), 47.1 (HfMe2),
48.0 (HfMe2), 55.0 (CMe3, Cipso), 107.9 (C5H3, Cipso), 114.3
(CH=CH2), 122.9 (C5H3), 125.2 (C5H3), 125.7 (C5H3), 126.9
(C5H3, Cipso), 134.9 (CH=CH2) ppm.
Synthesis of [Hf{η5-C5H3[SiMe2-η1-N(2,6-Me2C6H3)][SiMe2(CH2-
CH=CH2)]}Cl2] (9): Toluene (100 mL) was added at room tempera-
ture to a mixture of 5 (2 g, 5.66 mmol) and HfCl4 (1.81 g,
5.66 mmol). The mixture was stirred for 16 h and the solvent was
then removed under reduced pressure to give a residue which was
extracted into hexane (2×50 mL) to separate the LiCl formed. The
resulting solution was concentrated and cooled to –35 °C overnight
to give a colourless solid identified as 9 (1.0 g, 1.7 mmol, 30%
yield). C20H29Cl2HfNSi2 (589.02): calcd. C 40.78, H 4.96, N 2.38;
found C 40.77, H 5.09, N 2.23. 1H NMR (300 MHz, CDCl3,
25 °C): δ = 0.36 (s, 3 H, SiMe2), 0.39 (s, 3 H, SiMe2), 0.51 (s, 3 H,
SiMe2), 0.55 (s, 3 H, SiMe2), 1.80 (m, 2 H, SiCH2), 2.11 (s, 3 H,
C6H3 Me2), 2.14 (s, 3 H, C6H3 Me2), 4.88 (m, 2 H, CH=CH2), 5.77
(m, 1 H, CH=CH2), 6.64 (t, 1 H, C5H3), 6.80 (t, 1 H, C5H3), 7.07
(t, 1 H, C5H3), 6.82–7.02 (m, 3 H, C6H3) ppm. 13C{1H} NMR
(75 MHz, CDCl3, 25 °C): δ = –3.0 (SiMe2), –2.7 (SiMe2), 0.1
(SiMe2), 0.3 (SiMe2), 19.6 (C6H3 Me2), 19.7 (C6H3 Me2), 24.2
(SiCH2), 114.3 (CH=CH2), 117.9 (C5H3, Cipso), 123.9 (C5H3), 125.6
(C5H3), 125.8 (C5H3), 126.6–128.6 (C6H3), 133.7 (CH=CH2), 142.5
(C6H3, Cipso) ppm.
Synthesis of [Hf{η5-C5H3[SiMe2-η1-NtBu][SiMe2(CH2CH=CH2)]}-
(CH2Ph)2] (13): The same procedure described to prepare 11 was
applied using a 2  THF solution of MgClBz (4.4 mL, 8.8 mmol)
and 7 (2.4 g, 4.4 mmol) to give 13 as an orange oil (1.72 g,
2.64 mmol, 60% yield). C30H43HfNSi2 (652.34): calcd. C 55.24, H
1
6.64, N 2.15; found C 55.23, H 5.99, N 2.28. H NMR (300 MHz,
C6D6, 25 °C): δ = 0.22 (s, 3 H, SiMe2), 0.24 (s, 3 H, SiMe2), 0.38
(s, 3 H, SiMe2), 0.41 (s, 3 H, SiMe2), 1.19 (s, 9 H, CMe3), 1.40 (d,
J = 12.5 Hz, 1 H, CH2Ph), 1.47 (d, J = 11.5 Hz, 1 H, CH2Ph), 1.63
(m, 2 H, SiCH2), 1.84 (d, J = 12.5 Hz, 1 H, CH2Ph), 1.96 (d, J =
11.7 Hz, 1 H, CH2Ph), 4.83 (m, 2 H, CH=CH2), 5.69 (m, 1 H,
CH=CH2), 5.91 (t, 1 H, C5H3), 6.19 (t, 1 H, C5H3), 6.28 (t, 1 H,
C5H3), 6.77–7.20 (m, 10 H, C6H5) ppm. 13C{1H} NMR (75 MHz,
C6D6, 25 °C): δ = –2.8 (SiMe2), –2.6 (SiMe2), 1.4 (SiMe2), 2.0
(SiMe2), 25.0 (SiCH2), 34.5 (CMe3), 56.4 (CMe3, Cipso), 71.2
(HfCH2), 73.5 (HfCH2), 109.2 (C5H3, Cipso), 114.0 (CH=CH2),
122.0, 122.5, 125.3 (C5H3), 126.5, 126.7, 128. 2, 128.7, 128.8
(C6H5), 134.4 (CH=CH2), 147.0, 147.3 (C6H5, Cipso) ppm.
Synthesis of [Zr{η5-C5H3[SiMe2-η1-NtBu][SiMe2(CH2CH=CH2)]}-
Me2] (10): A solution of MgClMe in THF (3.3 mL, 10 mmol) was
added to a solution of 6 (2.3 g, 5.1 mmol) in hexane cooled to
–78 °C. The reaction mixture was slowly warmed to room tempera-
ture and then stirred for 16 h. The solution was filtered and the
solvent was removed under reduced pressure to give 10 as a brown
oil (1.3 g, 3.1 mmol, 60% yield). C18H35NSi2Zr (412.87): calcd. C
52.37, H 8.54, N 3.39; found C 52.74, H 9.13, N 3.04. 1H NMR
(300 MHz, C6D6, 25 °C): δ = 0.15 (s, 3 H, ZrMe2), 0.17 (s, 3 H,
ZrMe2), 0.26 (s, 3 H, SiMe2), 0.27 (s, 3 H, SiMe2), 0.35 (s, 6 H,
SiMe2), 1.36 (s, 9 H, CMe3), 1.70 (m, 2 H, SiCH2), 4.92 (m, 2 H,
CH=CH2), 5.80 (m, 1 H, CH=CH2), 6.27 (t, 1 H, C5H3), 6.36 (t,
1 H, C5H3), 6.72 (t, 1 H, C5H3) ppm. 13C{1H} NMR (75 MHz,
C6D6, 25 °C): δ = –2.9 (SiMe2), –2.7 (SiMe2), 1.5 (SiMe2), 2.0
(SiMe2), 24.9 (SiCH2), 34.2 (CMe3), 35.1 (ZrMe2), 35.7 (ZrMe2),
55.5 (CMe3, Cipso), 107.1 (C5H3, Cipso), 113.9 (CH=CH2), 122.8
(C5H3), 124.8 (C5H3), 125.2 (C5H3), 126.8 (C5H3, Cipso), 134.6
(CH=CH2) ppm.
Synthesis of [Zr{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}-
{η2-CMe=N(2,6-Me2C6H3)}2] (14):
A solution of 10 (1.0 g,
2.42 mmol) in toluene (50 mL) was treated with a toluene (20 mL)
solution of CN(2,6-Me2C6H3) (0.63 g, 4.84 mmol) at room tem-
perature. The mixture was stirred for 3 h and the solvent was then
removed under vacuum. The residue was extracted into pentane
(40 mL) and the solution was filtered and concentrated under re-
duced pressure to give a red oily product identified as compound
14 (1.31 g, 1.94 mmol, 80% yield). 1H NMR (300 MHz, C6D6,
25 °C): δ = 0.11 (s, 3 H, SiMe2), 0.25 (s, 3 H, SiMe2), 0.70 (s, 6 H,
SiMe2), 1.11 (s, 9 H, CMe3), 1.62 (m, 2 H, SiCH2), 1.89 (s, 3 H,
NMe2C6H3), 1.93 (s, 6 H, NMe2C6H3), 1.96 (s, 3 H, NMe2C6H3),
2.05 (s, 3 H, CMe2), 2.12 (s, 3 H, CMe2), 4.90 (m, 2 H, CH=CH2),
5.76 (m, 1 H, CH=CH2), 6.33 (t, 1 H, C5H3), 6.53 (t, 1 H, C5H3),
6.61 (t, 1 H, C5H3), 6.90–7.00 (m, 6 H, C6H3) ppm. 13C{1H} NMR
(75 MHz, C6D6, 25 °C): δ = –2.7 (SiMe2), –2.5 (SiMe2), 3.9
(SiMe2), 4.6 (SiMe2), 18.4, 18.7, 18.9, 19.6 (NMe2C6H3), 24.2
(SiCH2), 25.5, 25.6 (CMe2), 35.3 (CMe3), 55.8 (CMe3, Cipso), 113.4
(CH=CH2), 114.5 (C5H3, Cipso), 119.2, 121.4, 121.7 (C5H3), 125.3–
129.9 (C6H3), 135.1 (CH=CH2), 146.9, 147.4 (NC), 253.0, 257.1
(CMe2) ppm.
Synthesis of [Zr{η5-C5H3[SiMe2-η1-NtBu][SiMe2(CH2CH=CH2)]}-
(CH2Ph)2] (11): A 2  THF solution of MgClBz (5 mL, 10 mmol)
was added at –78 °C to a hexane solution of the dichloro complex
6 (2.3 g, 5.1 mmol). The mixture was stirred for 16 h while it was
warmed to room temp. After filtration to separate MgCl2, the sol-
vent was removed under vacuum to give 11 as a brown oil (1.73 g,
3.06 mmol, 60% yield). 1H NMR (300 MHz, C6D6, 25 °C): δ =
0.22 (s, 3 H, SiMe2), 0.24 (s, 3 H, SiMe2), 0.34 (s, 3 H, SiMe2), 0.36
(s, 3 H, SiMe2), 1.11 (s, 9 H, CMe3), 1.60 (m, 2 H, SiCH2), 1.50
(d, J = 11.0 Hz, 1 H, CH2Ph), 1.71 (d, J = 10.3 Hz, 1 H, CH2Ph),
2.10 (d, J = 11.2 Hz, 1 H, CH2Ph), 2.15 (d, J = 10.1 Hz, 1 H,
CH2Ph), 4.92 (m, 2 H, CH=CH2), 5.72 (m, 1 H, CH=CH2), 6.18
(t, 1 H, C5H3), 6.25 (t, 1 H, C5H3), 6.52 (t, 1 H, C5H3), 6.86–7.18
(m, 10 H, C6H5) ppm. 13C{1H} NMR (75 MHz, C6D6, 25 °C): δ
= –2.7 (SiMe2), –2.4 (SiMe2), 1.5 (SiMe2), 2.1 (SiMe2), 25.3
(SiCH2), 33.7 (CMe3), 54.4 (ZrCH2), 54.7 (CMe3, Cipso), 57.6
Synthesis of [Zr{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}-
{η2-C(CH2Ph)=N(2,6-Me2C6H3)}2] (15): A toluene (10 mL) solu-
(ZrCH2), 109.7 (C5H3, Cipso), 114.0 (CH=CH2), 122.4, 124.1, 125.4 tion of CN(2,6-Me2C6H3) (0.37 g, 2.83 mmol) was added to a solu-
(C5H3), 126.8, 127.7, 128. 3, 129.6, 129.7 (C6H5), 134.4 (CH=CH2),
145.5, 145.9 (C6H5, Cipso) ppm.
tion of 11 (0.80 g, 1.42 mmol) in toluene (40 mL) and the mixture
was stirred at room temperature overnight. The solvent was re-
Eur. J. Inorg. Chem. 2005, 3962–3970
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
3967

C. Ramos, P. Royo, M. Lanfranchi, M. A. Pellinghelli, A. Tiripicchio
FULL PAPER
moved under vacuum and the resulting residue was extracted into
pentane (40 mL). The solution was filtered and the solvent was
removed under vacuum to give an orange oil identified as com-
pound 15 (0.76 g, 0.92 mmol, 65% yield). 1H NMR (300 MHz,
C6D6, 25 °C): δ = 0.07 (s, 3 H, SiMe2), 0.08 (s, 3 H, SiMe2), 0.64
(s, 3 H, SiMe2), 0.74 (s, 3 H, SiMe2), 1.12 (s, 9 H, CMe3), 1.45 (m,
2 H, SiCH2), 1.65 (s, 3 H, NMeC6H3), 1.87 (s, 3 H, NMeC6H3),
1.97 (s, 3 H, NMeC6H3), 2.12 (s, 3 H, NMeC6H3), 3.47 (d, J =
14.3 Hz, 1 H, CH2Ph), 3.60 (d, J = 17.3 Hz, 1 H, CH2Ph), 3.64 (d,
J = 14.6 Hz, 1 H, CH2Ph), 3.80 (d, J = 17.3 Hz, 1 H, CH2Ph), 4.85
(m, 2 H, CH=CH2), 5.63 (m, 1 H, CH=CH2), 6.10 (t, 1 H, C5H3),
6.21 (t, 1 H, C5H3), 6.84 (t, 1 H, C5H3), 6.50–7.40 (m, C6H3, C6H5)
ppm. 13C{1H} NMR (75 MHz, C6D6, 25 °C): δ = –2.1 (SiMe2),
–1.9 (SiMe2), 4.2 (SiMe2), 4.6 (SiMe2), 18.8, 19.0, 20.1, 20.3
(NMeC6H3), 26.2 (SiCH2), 36.1 (CMe3), 45.7, 46.1 (CH2Ph), 56.4
(CMe3, Cipso), 113.6 (CH=CH2), 115.4 (C5H3, Cipso), 117.1, 121.2,
123.0 (C5H3), 125.5–130.7 (C6H5, C6H3), 135.4 (CH=CH2), 137.7,
137.8, 147.5, 148.3 (C6H5, C6H3, Cipso), 253.0, 257.1 [C(CH2Ph)2]
ppm.
(CH=CH2), 137.4, 137.5, 147.0, 147.5 (C6H5, C6H3, Cipso), 261.2,
265.4 [C(CH2Ph)2] ppm.
Synthesis of [Zr{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}-
{η-N(2,6-Me2C6H3)CMe=CMe-η-N(2,6-Me2C6H3)}] (18): A tolu-
ene (50 mL) solution of 14 (0.63 g, 0.93 mmol) was heated at 70 °C
for 2 d in a Teflon-valved Schlenk vessel. The solvent was then
removed under vacuum and the residue was extracted into pentane
(40 mL). After removal of the solvent under vacuum, compound
18 was isolated as a red oil (0.63 g, 0.93 mmol, 100% yield). 1H
NMR (300 MHz, C6D6, 25 °C): δ = –0.25 (s, 3 H, SiMe2), –0.12 (s,
3 H, SiMe2), 0.64 (s, 3 H, SiMe2), 0.66 (s, 3 H, SiMe2), 1.10 (s, 9
H, CMe3), 1.23 (m, 2 H, SiCH2), 1.59 (s, 3 H, NMeC6H3), 1.62 (s,
3 H, NMeC6H3), 2.04 (s, 3 H, NMeC6H3), 2.09 (s, 3 H, NMeC6H3),
2.45 (s, 3 H, CMe2), 2.52 (s, 3 H, CMe2), 4.74 (m, 2 H, CH=CH2),
5.50 (m, 1 H, CH=CH2), 6.16 (t, 1 H, C5H3), 6.35 (t, 1 H, C5H3),
6.53 (t, 1 H, C5H3), 6.90–7.10 (m, 6 H, C6H3) ppm. 13C{1H} NMR
(75 MHz, C6D6, 25 °C): δ = –4.4 (SiMe2), –3.5 (SiMe2), 3.4
(SiMe2), 3.6 (SiMe2), 16.9, 17.9, 19.8, 19.9 (NMeC6H3), 21.2, 21.7
(CMe2), 24.5 (SiCH2), 35.7 (CMe3), 55.5 (CMe3, Cipso), 110.8, 111.2
(NC=CN), 113.3 (CH=CH2), 114.5 (C5H3, Cipso), 122.7, 123.4,
124.5 (C5H3), 125.3–129.5 (C6H3), 132.3, 133.2, 133.3, 133.8 (C6H3,
Synthesis
of
[Hf{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
toluene solution
CH2)]}{η2-CMe=N(2,6-Me2C6H3)}2] (16):
A
Cipso), 134.8 (CH=CH2), 149.9, 150.1 (NC) ppm.
(60 mL) of CN(2,6-Me2C6H3) (0.47 g, 3.60 mmol) and 12 (0.90 g,
1.80 mmol) was stirred at room temperature overnight. The solvent
was removed under vacuum and the residue was extracted into pen-
tane (40 mL). After filtration and elimination of the solvent under
vacuum, compound 16 was obtained as a red oily product (1.37 g,
1.1 mmol, 80% yield). C36H53HfN3Si2 (762.50): calcd. C 56.71, H
Synthesis of
[Hf{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
CH2)]}{η-N(2,6-Me2C6H3)CMe=CMe-η-N(2,6-Me2C6H3)}] (19):
A toluene (50 mL) solution of 15 (0.60 g, 0.79 mmol) was heated
at 80 °C for 2 d in a Teflon-valved Schlenk vessel and the solvent
was then removed under vacuum. The residue was extracted into
pentane (40 mL) and the solvent was removed under vacuum to
give compound 19 as a brown oil. (0.60 g, 0.79 mmol, 100% yield).
C36H53HfN3Si2 (762.50): calcd. C 56.71, H 7.01, N 5.51; found C
56.42, H 7.02, N 5.52. 1H NMR (300 MHz, C6D6, 25 °C): δ =
–0.22 (s, 3 H, SiMe2), –0.12 (s, 3 H, SiMe2), 0.65 (s, 3 H, SiMe2),
0.68 (s, 3 H, SiMe2), 1.08 (s, 9 H, CMe3), 1.29 (m, 2 H, SiCH2),
1.60 (s, 3 H, NMeC6H3), 1.61 (s, 3 H, NMeC6H3), 1.99 (s, 3 H,
NMeC6H3), 2.06 (s, 3 H, NMeC6H3), 2.41 (s, 3 H, CMe2), 2.49 (s,
3 H, CMe2), 4.79 (m, 2 H, CH=CH2), 5.53 (m, 1 H, CH=CH2),
6.14 (t, 1 H, C5H3), 6.46 (t, 1 H, C5H3), 6.65 (t, 1 H, C5H3), 6.91–
7.08 (m, 6 H, C6H3) ppm. 13C{1H} NMR (75 MHz, C6D6, 25 °C):
δ = –4.0 (SiMe2), –3.3 (SiMe2), 3.9 (SiMe2), 4.0 (SiMe2), 17.0, 18.5,
20.0, 20.2 (NMe2C6H3), 21.4, 22.6 (CMe2), 24.7 (SiCH2), 35.6
(CMe3), 55.7 (CMe3, Cipso), 112.0, 112.1 (NC=CN), 113.3
(CH=CH2), 114.9 (C5H3, Cipso), 123.3, 123.4, 124.6 (C5H3), 125.4–
129.5 (C6H3), 132.0, 132.5, 132.8, 133.2 (C6H3, Cipso), 134.8
(CH=CH2), 149.8, 149.9 (NC) ppm.
1
7.01, N 5.51; found C 56.42, H 7.02, N 5.52. H NMR (300 MHz,
C6D6, 25 °C): δ = 0.09 (s, 3 H, SiMe2), 0.25 (s, 3 H, SiMe2), 0.67
(s, 3 H, SiMe2), 0.70 (s, 3 H, SiMe2), 1.08 (s, 9 H, CMe3), 1.59 (m,
2 H, SiCH2), 1.95 (s, 3 H, NMeC6H3), 1.96 (s, 6 H, NMe2C6H3),
1.98 (s, 3 H, NMeC6H3), 2.10 (s, 3 H, CMe), 2.19 (s, 3 H, CMe),
4.86 (m, 2 H, CH=CH2), 5.72 (m, 1 H, CH=CH2), 6.27 (t, 1 H,
C5H3), 6.46 (t, 2 H, C5H3), 6.95–7.00 (m, 6 H, C6H3) ppm. 13C{1H}
NMR (75 MHz, C6D6, 25 °C): δ = –2.8 (SiMe2), –2.5 (SiMe2), 4.1
(SiMe2), 4.6 (SiMe2), 18.5, 18.6, 18.8, 19.8 (NMeC6H3), 24.6
(SiCH2), 25.7, 25.9 (CMe2), 35.5 (CMe3), 55.5 (CMe3, Cipso), 113.4
(CH=CH2), 114.1 (C5H3, Cipso), 118.3, 120.3, 120.7 (C5H3), 125.3–
129.5 (C6H3), 135.1 (CH=CH2), 146.3, 146.8 (NC), 262.3, 268.6
(CMe2) ppm.
Synthesis
of
[Hf{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=
CH2)]}{η2-C(CH2Ph)=N(2,6-Me2C6H3)}2] (17): A toluene (50 mL)
solution containing 13 (0.80 g, 1.23 mmol) and CN(2,6-Me2C6H3)
(0.32 g, 2.46 mmol) was stirred at room temperature for 2 d. The
solvent was removed under reduced pressure and the residue was
extracted into pentane (40 mL). After filtration, the solvent was
removed under vacuum to give an orange oil identified as com-
pound 17 (0.79 g, 0.86 mmol, 70% yield). C48H61HfN3Si2 (914.69):
Synthesis of [Zr{η5-C5H3(SiMe2-η1-NtBu)[SiMe2(CH2CH=CH2)]}-
{η-N(2,6-Me2C6H3)C(CH2Ph)=C(CH2Ph)-η-N(2,6-Me2C6H3)}]
(20): A toluene (50 mL) solution of 16 (0.80 g, 0.97 mmol) was
heated at 80 °C for 4 d and the solvent was then removed under
vacuum. The residue was extracted into pentane (40 mL) and the
solvent was removed under vacuum to give a brown oil identified
as compound 20 (0.80 g, 0.97 mmol, 100% yield). 1H NMR
(300 MHz, C6D6, 25 °C): δ = –0.29 (s, 3 H, SiMe2), –0.15 (s, 3 H,
1
calcd. C 63.03, H 6.72, N 4.59; found C 63.00, H 6.55, N 4.50. H
NMR (300 MHz, C6D6, 25 °C): δ = 0.06 (s, 3 H, SiMe2), 0.09 (s, 3
H, SiMe2), 0.64 (s, 3 H, SiMe2), 0.71 (s, 3 H, SiMe2), 1.11 (s, 9 H,
CMe3), 1.44 (m, 2 H, SiCH2), 1.72 (s, 3 H, NMeC6H3), 1.89 (s, 3
H, NMeC6H3), 2.00 (s, 3 H, NMeC6H3), 2.11 (s, 3 H, NMeC6H3), SiMe2), 0.63 (s, 3 H, SiMe2), 0.65 (s, 3 H, SiMe2), 1.01 (s, 9 H,
3.54 (d, J = 14.5 Hz, 1 H, CH2Ph), 3.69 (d, J = 16.8 Hz, 1 H, CMe3), 1.18 (m, 2 H, SiCH2), 1.77 (s, 3 H, NMeC6H3), 1.98 (s, 3
CH2Ph), 3.72 (d, J = 14.5 Hz, 1 H, CH2Ph), 3.86 (d, J = 17.0 Hz, H, NMeC6H3), 2.47 (s, 3 H, NMeC6H3), 2.50 (s, 3 H, NMeC6H3),
1 H, CH2Ph), 4.83 (m, 2 H, CH=CH2), 5.62 (m, 1 H, CH=CH2), 3.21 (d, J = 15.2 Hz, 1 H, CH2Ph), 3.61 (d, J = 14.3 Hz, 1 H,
6.09 (t, 1 H, C5H3), 6.21 (t, 1 H, C5H3), 6.72 (t, 1 H, C5H3), 6.55– CH2Ph), 3.87 (d, J = 14.5 Hz, 1 H, CH2Ph), 4.35 (d, J = 15.4 Hz,
7.35 (m, C6H3, C6H5) ppm. 13C{1H} NMR (75 MHz, C6D6, 1 H, CH2Ph), 4.76 (m, 2 H, CH=CH2), 5.50 (m, 1 H, CH=CH2),
25 °C): δ = –2.5 (SiMe2), –2.3 (SiMe2), 3.9 (SiMe2), 4.5 (SiMe2),
18.6, 19.7, 20.0 (NMeC6H3), 25.9 (SiCH2), 36.0 (CMe3), 45.8, 46.2
6.11 (t, 1 H, C5H3), 6.20 (t, 1 H, C5H3), 6.59 (t, 1 H, C5H3), 6.65–
7.15 (m, C6H5, C6H3) ppm. 13C{1H} NMR (75 MHz, C6D6,
(CH2Ph), 55.7 (CMe3, Cipso), 113.3 (CH=CH2), 115.8 (C5H3, Cipso), 25 °C): δ = –4.7 (SiMe2), –3.7 (SiMe2), 3.1 (SiMe2), 3.9 (SiMe2),
120.2, 125.4, 126.7 (C5H3), 128.5–130.4 (C6H5, C6H3), 135.1 20.2, 20.3, 21.5, 22.0 (NMeC6H3), 24.5 (SiCH2), 35.6 (CMe3), 38.3,
3968
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Inorg. Chem. 2005, 3962–3970

Zr and Hf Complexes with (Allylsilyl)(η-amidosilyl)cyclopentadienyl Ligands
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X-ray Structure Determination of [ZrCl(µ-Cl){η5-C5H3(SiMe2-η1-
NtBu) [SiMe2(CH2CH=CH2)]}]2 (6): Crystals of compound 6 were
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Empirical formula
Formula mass
Temperature
C32H58Cl4N2Si4Zr2
907.40
293(2) K
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0.71073 Å
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936
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3969

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Received: April 28, 2005
Published Online: August 31, 2005
3970
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 3962–3970