Synthesis, structural characterization and reactivity of new tin bridged ansa-bis(cyclopentadiene) compounds: X-ray crystal structures of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)

Article abstract of DOI:10.1016/j.jorganchem.2007.03.031

The organo-tin compounds, Me₂Sn(C₅H₄R-1)₂ (R = Me (1), Prⁱ (2), Bu^t (3), SiMe₃ (4)) and Me₂Sn(C₅Me₄R-1)₂ (R = H (5), SiMe₃

Full text of DOI:10.1016/j.jorganchem.2007.03.031

Journal of Organometallic Chemistry 692 (2007) 3057–3064
www.elsevier.com/locate/jorganchem
Synthesis, structural characterization and reactivity of new tin bridged
ansa-bis(cyclopentadiene) compounds: X-ray crystal structures
of Me2Sn(C5Me4R-1)2 (R = H, SiMe3)
a
a,
a
Santiago Gomez-Ruiz , Sanjiv Prashar *, Mariano Fajardo ,
´
b
b,
*
Antonio Antinolo , Antonio Otero
˜
a
Departamento de Quı´mica Inorga´nica y Analı´tica, E.S.C.E.T., Universidad Rey Juan Carlos, 28933 Mo´stoles, Madrid, Spain
Departamento de Quı´mica Inorga´nica, Orga´nica y Bioquı´mica, Universidad de Castilla-La Mancha, Facultad de Quı´micas, Campus Universitario,
13071-Ciudad Real, Spain
b
Received 19 January 2007; received in revised form 21 March 2007; accepted 21 March 2007
Available online 27 March 2007
This paper is dedicated to the memory of our friend Dr. Anthony G. Avent, University of Sussex.
Abstract
The organo-tin compounds, Me2Sn(C5H4R-1)2 (R = Me (1), Pri (2), But (3), SiMe3 (4)) and Me2Sn(C5Me4R-1)2 (R = H (5), SiMe3
(6)), were prepared by the reaction of Me2SnCl2 with the lithium or sodium derivative of the corresponding cyclopentadiene. Compounds
1–6 have been characterized by multinuclear NMR spectroscopy (1H, 13C, 119Sn). In addition the molecular structures of 5 and 6 were
determined by single crystal X-ray diffraction studies. The transmetalation reaction of 1–6 with ZrCl4 or [NbCl4(THF)2] gave the cor-
responding metallocene complexes in high yields.
ꢀ 2007 Elsevier B.V. All rights reserved.
Keywords: Stannylcyclopentadiene; ansa-Compounds; Tin; Zirconium; Niobium
1. Introduction
cation of these tin complexes is that of transmetalation
reactions which has proved to be an efficient synthetic
route in the preparation of early transition metallocene
complexes providing not only high yields but also a high
degree of selectivity [9]. As a continuation of our work in
group 4 and 5 metallocene chemistry [10], we report in
this paper the synthesis of novel tin bridged ansa-cyclo-
pentadiene compounds and their use in the synthesis of
zirconocene and in the optimization of the preparation
of niobocene complexes.
Since the discovery of ferrocene in 1951 by Pauson and
Miller [1], transition metal compounds with cyclopenta-
dienyl ligands has been one of the most important fields
in organometallic chemistry [2], due to their application
in organic synthesis [3], homogeneous [4] and heteroge-
neous catalysis [5] and even as anti-tumoral agents [6].
Tin cyclopentadiene compounds were initially synthesised
in 1964 in order to study and develop 117Sn and 119Sn
NMR spectroscopic techniques [7]. Twenty years later
these compounds were prepared for the principal purpose
of synthetic and structural studies [8]. An excellent appli-
2. Results and discussion
The preparation of dimethyltin bridged ansa-bis(cyclo-
pentadiene) compounds was achieved via the reaction of
2 equiv. of the lithium or sodium cyclopentadienyl
derivative with SnMe2Cl2.
*
Corresponding authors. Tel.: +34 914887186; fax: +34 914888143
(S. Prashar).
E-mail address: sanjiv.prashar@urjc.es (S. Prashar).
0022-328X/$ - see front matter ꢀ 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.03.031

3058
S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
Table 1
1H NMR data for 1–6a
Compound
SnMe2
C5H4 or C5H3
C5Me4
R
Me2Sn(C5H4Me-1)2 (1)
ꢀ0.23 (s, 6H)
5.54 (m, 4H),
2.10 (s, 6H)
3J(1H–117,119Sn) 13.6 Hz
2J(1H–119Sn) 53.6 Hz
2J(1H–117Sn) 51.2 Hz
3J(1H–117,119Sn) 33.6 Hz
5.88 (m, 4H)
Me2Sn(C5H4Pri-1)2 (2)
ꢀ0.26 (s, 6H)
5.26 (m, 4H),
1.19 (d, 12H),
2J(1H–119Sn) 52.0 Hz
2J(1H–117Sn) 49.6 Hz
3J(1H–117,119Sn) 41.6 Hz
6.18 (m, 4H)
3J(1H–1H) 7.0 Hz
2.75 (sept, 2H)
3J(1H–117,119Sn) 41.4 Hz
Me2Sn(C5H4But-1)2 (3)
Me2Sn(C5H4SiMe3-1)2 (4)
Me2Sn(C5Me4H-1)2 (5)
ꢀ0.21 (s, 6H)
5.15 (m, 4H),
1.30 (s, 18H)
2J(1H–119Sn) 52.8 Hz
2J(1H–117Sn) 51.2 Hz
3J(1H–117,119Sn) 46.4 Hz
6.42 (m, 4H)
ꢀ0.20 (s, 6H)
6.05 (m, 4H),
0.11 (s, 18H)
2J(1H–119Sn) 52.8 Hz
2J(1H–117Sn) 50.4 Hz
3J(1H–117,119Sn) 29.2 Hz
6.54 (m, 4H)
ꢀ0.20 (s, 6H)
1.86 (s, 12H),
1.91 (s, 12H)
3.51 (s, 2H)
2J(1H–117,119Sn) 91.6 Hz
2J(1H–119Sn) 49.6 Hz
2J(1H–117Sn) 47.6 Hz
Me2Sn(C5Me4{SiMe3}-1)2 (6)
0.53 (s, 6H)
1.79 (s, 12H),
1.84 (s, 12H)
ꢀ0.09 (s, 18H)
2J(1H–119Sn) 47.2 Hz
2J(1H–117Sn) 44.8
a
400 MHz, C6D6, chemical shifts in d.
the tin atom, tin satellite signals were observed with values
R
R
Sn
R
3
1
of J H–117,119Sn of ca. 30 Hz.1
2
+ Me2SnCl2
1
In the H NMR spectrum of 1, a singlet was observed
M
for the protons of the methyl substituent of the cyclopenta-
M = Li, R = But, SiMe3
R = Me (1), Pri (2), But (3), SiMe3 (4)
dienyl ring along with its tin satellite signals (3J1H–117,119Sn
M = Na, R = Me, Pri
1
13.6 Hz). Compound 2 gave, in the H NMR spectrum, a
ð1Þ
doublet signal, assigned to the methyl groups of the isopro-
pyl unit, at 1.19 ppm and a septuplet, at 2.75 ppm, with its
tin satellite signals (3J1H–117,119Sn 41.6 Hz), corresponding
to the remaining proton. For 3 and 4, a singlet signal was
R
R
Sn
R
2
+ Me2SnCl2
ð2Þ
Li
1
observed, in the H NMR spectra, for the protons of the
R = H (5), SiMe3 (6)
tert-butyl or trimethylsilyl groups, respectively.
1
The H NMR spectra of 5 and 6 are similar in nature.
Compounds 1–6 have been characterized by 1H
(Table 1), 13C{1H} (Table 2) and 119Sn (Table 3) NMR
spectroscopy and by mass spectrometry (see Section 4).
NMR spectral data for 1–6 indicated that only one of the
possible isomers was present and differs from the
observation of multiple isomers in analogous silicon and
germanium bridged ansa-bis-cyclopentadiene ligands
Two singlets were observed for the methyl substituents of
the cyclopentadienyl rings between 1.8 and 1.9 ppm. For
5 a signal, at 3.51 ppm, with tin satellites (2J1H–117,119Sn
91.6 Hz) was recorded for the proton in the C1 position.
For 6 a singlet was observed at ꢀ0.09 ppm and assigned
to the trimethylsilyl protons.
In the 13C{1H} NMR spectra of 1–6, a signal, at ca.
ꢀ10 ppm, was observed for the SnMe2 carbon atoms. Tin–
1
[8c,11]. In the H NMR spectra of 1–6, a singlet, at ca.
1
carbon coupling gave values of approximately J13C–117Sn
ꢀ0.2 ppm, corresponding to the six protons of the SnMe2
bridging unit, was observed. In addition, the satellite
signals due to coupling with the 117Sn and 119Sn isotopes
at a two bond distance could be easily distinguished and
gave values of approximately, 1H–117Sn 50 Hz and
1H–119Sn 52 Hz.
330 Hz and 13C–119Sn 350 Hz. Three signals were recorded
for the cyclopentadienyl carbon atoms. The C1 atom gave
a signal at ca. 100 ppm for 1–4 and 60 ppm for 5 and 6. In
all cases, the coupling constant, at one bond distance,
between the 13C and 117Sn and 119Sn nuclei were of the order
of 45 Hz.
In the 1H NMR spectra of 1–4, two multiplets, at ca. 5.5
and 5.9 ppm, were assigned to the four C5 ring protons.
This indicates that the symmetry of the molecule is such
that the alkyl substituent is located in the C1 position of
the cyclopentadienyl ring. For the equivalent cyclopenta-
dienyl ring protons, C2 and C5, at three bond distance to
1
In some cases we were unable to resolve the independent satellite
signals corresponding to the two tin nuclei and therefore the coupling
constant given is an approximate value that can be applied to either
nucleus.

S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
3059
Table 2
13C{1H} NMR data for 1–6a
Compound
SnMe2
C5
C5Me4
R
Me2Sn(C5H4Me-1)2 (1)
ꢀ9.6
103.4,
15.4
1J(13C–119Sn) 346.2 Hz
1J(13C–117Sn) 331.6 Hz
1J(13C–117,119Sn) 40.1 Hz
115.7, 138.9
Me2Sn(C5H4Pri-1)2 (2)
ꢀ9.3
96.0,
24.0, 29.4
31.5, 32.5
ꢀ0.4
1J(13C–119Sn) 346.0 Hz
1J(13C–117Sn) 329.2 Hz
1J(13C–117,119Sn) 37.3 Hz
120.5, 150.0
Me2Sn(C5H4But-1)2 (3)
Me2Sn(C5H4SiMe3-1)2 (4)
Me2Sn(C5Me4H-1)2 (5)
Me2Sn(C5Me4{SiMe3}-1)2 (6)
ꢀ9.2
92.0,
1J(13C–119Sn) 344.4 Hz
1J(13C–117Sn) 329.2 Hz
1J(13C–117,119Sn) 43.6 Hz
123.8, 152.9
ꢀ7.2
100.1,
1J(13C–119Sn) 356.6 Hz
1J(13C–117Sn) 341.4 Hz
1J(13C–117,119Sn) 44.0 Hz
112.5, 133.2
ꢀ10.4
57.3,
11.3, 13.9
11.9, 15.7
1J(13C–119Sn) 348.3 Hz
1J(13C–117Sn) 330.7 Hz
1J(13C–117,119Sn) 45.6 Hz
130.4, 133.2
ꢀ2.1
59.5,
ꢀ0.1
1J(13C–119Sn) 354.4 Hz
1J(13C–117Sn) 340.4 Hz
1J(13C–117,119Sn) 44.2 Hz
133.0, 135.1
a
100 MHz, C6D6, chemical shifts in d.
Table 3
119Sn NMR data for 1–6a
Compound
SnMe2
Me2Sn(C5H4Me-1)2 (1)
Me2Sn(C5H4Pri-1)2 (2)
Me2Sn(C5H4But-1)2 (3)
Me2Sn(C5H4SiMe3-1)2 (4)
Me2Sn(C5Me4H-1)2 (5)
Me2Sn(C5Me4{SiMe3}-1)2 (6)
18.0
22.9
24.0
11.7
34.1
ꢀ16.6
a
149 MHz, C6D6, chemical shifts in d.
One signal was observed in the 119Sn NMR spectra of
1–6. This signal was displaced upfield for the trimethylsi-
lyl containing compounds (4 and 6). For 1–3 and 5,
increasing alkyl substitution results in downfield displace-
ment of the tin signal.
The molecular structures of 5 and 6 were established by
single-crystal X-ray diffraction studies. The molecular
structures and atomic numbering schemes are shown in
Figs. 1 and 2. Selected bond lengths and angles for 5 and
6 are given in Tables 4 and 5, respectively. For 5, two dis-
tinct molecules were located in the asymmetric unit.
The molecular structures of 5 and 6 are of a similar nat-
ure. The geometry around the tin atom is clearly tetrahe-
Fig. 1. Molecular structure and atom-labeling scheme for Me2Sn(C5-
Me4H-1)2 (5), with thermal ellipsoids at 30% probability.
dral. The cyclopentadienyl units are essentially planar
1
˚
˚
˚
with the C atom located only 0.100 A, 0.100 A, 0.094 A
˚
˚
metal with the aromatic ring of the sort which has recently
been reported for beryllium and zinc metallocene com-
plexes [12]. Selected structural data of 5 and 6 can be com-
pared with similar tin bridged ansa-bis(cyclopentadiene)
compounds using Table 6.
The transmetalation reaction of 1–6 with ZrCl4 or
[NbCl4(THF)2] gave the corresponding metallocene com-
plexes, 7–12, in high yields (Eqs. (3) and (4)). The reaction
was carried out in toluene in reflux and for 24 h. After
and 0.087 A for 5 and 0.038 A for 6 out of the plane
defined by the other four carbon atoms. Three long and
two short bond distances are observed between the carbon
atoms of the C5 ring. The hybridization of C1 atom of the
cyclopentadienyl moiety is sp3 and the r-bond lengths with
the tin atom are slightly longer than those recorded for the
tin-methyl carbon distances. The tin-ring plane angles of
(111.41ꢁ, 115.85ꢁ, 116.22ꢁ and 111.86ꢁ for 5; 125.35ꢁ and
120.39ꢁ for 6) rule out a p–g1 type of interaction of the

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S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
Table 5
˚
Selected bond lengths (A) and angles (ꢁ) for 6
6
˚
Bond lengths (A)
Sn(1)–C(1)
Sn(1)–C(2)
Si(1)–C(2)
Si(1)–C(11)
Si(1)–C(12)
Si(1)–C(13)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(2)–C(6)
2.151(2)
2.190(2)
1.905(2)
1.876(3)
1.871(3)
1.863(3)
1.502(3)
1.350(3)
1.456(3)
1.358(3)
1.505(3)
Bond angles (ꢁ)
C(1)–Sn(1)–C(1A)
C(1)–Sn(1)–C(2)
103.8(2)
109.00(9)
111.98(9)
110.9(1)
114.3(1)
109.5(1)
111.8(1)
110.2(1)
107.6(1)
109.4(2)
109.4(2)
109.2(2)
109.1(2)
102.8(2)
Fig. 2. Molecular structure and atom-labeling scheme for Me2Sn(C5-
Me4{SiMe3}-1)2 (6), with thermal ellipsoids at 30% probability.
C(1)–Sn(1)–C(2A)
C(2)–Sn(1)–C(2A)
Sn(1)–C(2)–Si(1)
Sn(1)–C(2)–C(3)
Sn(1)–C(2)–C(6)
Si(1)–C(2)–C(3)
Si(1)–C(2)–C(6)
C(2)–C(3)–C(4)
C(3)–C(4)–C(5)
C(4)–C(5)–C(6)
C(2)–C(6)–C(5)
C(3)–C(2)–C(6)
Table 4
˚
Selected bond lengths (A) and angles (ꢁ) for 5
5a
5b
˚
Bond lengths (A)
Sn(1)–C(1)
Sn(1)–C(2)
Sn(1)–C(3)
Sn(1)–C(12)
C(3)–C(4)
C(4)–C(5)
C(5)–C(6)
C(6)–C(7)
C(3)–C(7)
C(12)–C(13)
C(13)–C(14)
C(14)–C(15)
C(15)–C(16)
C(12)–C(16)
2.145(4)
2.144(4)
2.195(4)
2.205(4)
1.480(5)
1.356(5)
1.459(5)
1.359(5)
1.497(5)
1.475(6)
1.353(6)
1.457(6)
1.353(6)
1.480(6)
2.149(4)
2.158(4)
2.206(4)
2.202(4)
1.483(5)
1.357(6)
1.460(6)
1.358(6)
1.485(6)
1.494(6)
1.363(6)
1.460(5)
1.353(6)
1.472(6)
filtrate in the case of the zirconocene complexes and 12b.
For the remaining niobocene complexes, SnMe2Cl2 was
eliminated by filtration of the toluene suspension and the
final product obtained by crystallization of the filtrate.
The zirconocene complexes were characterized satisfacto-
Table 6
Selected structural data of tin bridged ansa-bis(cyclopentadiene)
compounds
Bond angles (ꢁ)
C(1)–Sn(1)–C(2)
C(1)–Sn(1)–C(3)
C(1)–Sn(1)–C(12)
C(2)–Sn(1)–C(3)
C(2)–Sn(1)–C(12)
C(3)–Sn(1)–C(12)
Sn(1)–C(3)–C(4)
Sn(1)–C(3)–C(7)
Sn(1)–C(12)–C(13)
Sn(1)–C(12)–C(16)
C(3)–C(4)–C(5)
C(4)–C(5)–C(6)
C(5)–C(6)–C(7)
C(6)–C(7)–C(3)
C(4)–C(3)–C(7)
C(12)–C(13)–C(14)
C(13)–C(14)–C(15)
C(14)–C(15)–C(16)
C(12)–C(16)–C(15)
C(13)–C(12)–C(16)
Sn–C1(Cp) C1(Cp)–Sn–
Ref.
106.4(2)
110.7(2)
111.2(2)
110.1(2)
112.2(2)
106.3(1)
105.5(3)
103.5(2)
106.2(2)
107.6(3)
109.2(3)
108.9(3)
109.2(3)
108.3(3)
104.0(3)
108.5(4)
108.8(4)
109.4(4)
108.0(4)
104.9(3)
107.0(2)
111.4(2)
112.1(2)
112.0(2)
108.9(2)
105.5(1)
107.5(2)
106.7(3)
104.1(2)
105.0(2)
108.7(4)
108.9(3)
109.3(4)
108.3(4)
104.5(3)
108.0(3)
109.2(3)
108.7(3)
109.4(3)
104.4(3)
Compound
10
(Cp)
˚
(A)
C
(ꢁ)
Me2Sn(C5Me4H)2 (5)
2.195(4)
2.205(4) 106.3(1)
This
work
2.206(4) 105.5(1)
2.202(4)
Me2Sn(C5Me4SiMe3)2 (6)
2.190(2) 110.9(1)
This
work
[9h]
[9h]
[9h]
meso-Me2Sn(C5H3But)2SiMe2
meso-Me2Sn(C5Me2H2)2SiMe2
meso-Me2Sn(C5MeH2But)2SiMe2
2.214(4) 102.6(2)
2.206(4) 103.7(2)
2.197(2) 109.0(1)
rac-Me2Sn(C5MeH2But)2SiMe2
2.215(7) 109.3(3)
2.205(8)
[9e]
rac-Sn{(C5H3But)2(SiMe2)2(C5H3But)2} 2.204(2) 108.8(1)
2.196(2) 110.6(1)
2.197(2) 108.8(1)
2.203(2) 110.0(1)
108.4(1)
110.1(1)
[9e]
[9f]
evaporation of toluene and extraction with hexane,
SnMe2Cl2 was easily removed by filtration and the metallo-
cene dichloride obtained by crystallization of the hexane
meso-Me2Sn(C5H3But)2Si(Me)CH2Ph 2.206(2)
2.199(2) 100.6(1)

S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
3061
rily by elemental analysis and gave NMR spectra identical
to those previously reported for these compounds [13]. The
successful synthesis of the niobocene complexes [14] was
also confirmed by elemental analysis and mass spectrome-
try. The yields of the metallocene complexes, 7–12, pre-
pared via the tin transmetalation reactions were
comparable or superior to those reported using the tradi-
tional metathesis reactions with group one cyclopentadie-
nyl compounds [13,14].
reduced pressure and hexane (40 ml) added. The suspension
was filtered and the filtrate concentrated (5 ml). Cooling to
ꢀ30 ꢁC yielded the title compound as a yellow crystalline
solid (2.57 g, 72%). MS electron impact (m/e (relative inten-
sity)): 308 (15) [M+], 293 (25) [M+ꢀMe], 229 (55)
[M+ꢀC5H4Me], 79 (100) [M+ꢀMe2SnC5H4Me]. Anal. Calc.
for C14H20Sn: C, 54.77; H, 6.57. Found: C, 54.51; H, 6.55%.
4.3. Synthesis of Me2Sn(C5H4Pri-1)2 (2)
R
Cl
Cl
R
Sn
R
The preparation of 2 was carried out in an identical man-
ner to 1. Li(C5H4Pri) (2.00 g, 15.36 mmol) and SnMe2Cl2
(1.69 g, 7.68 mmol). Yield: 1.95 g, 70%. MS electron impact
(m/e (relative intensity)): 363 (1) [M+], 348 (9) [M+ꢀMe],
256 (47) [M+ꢀC5H4Pri], 226 (39) [M+ꢀC5H4Pri,
ꢀ2 · Me], 106 (100) [M+ꢀMe2SnC5H4Pri]. Anal. Calc. for
C18H28Sn: C, 59.54; H, 7.77. Found: C, 59.51; H, 7.76%.
M
+ MCl4
-SnMe2Cl2
R
ð3Þ
ð4Þ
R = Me (7), Pri (8), But (9), SiMe3 (10)
M= Zr (a); Nb (b)
R
R
Sn
R
Cl
Cl
4.4. Synthesis of Me2Sn(C5H4But-1)2 (3)
M
R
+ MCl4
-SnMe2Cl2
The preparation of 3 was carried out in an identical man-
ner to 1. Li(C5H4But) (2.00 g, 15.60 mmol) and SnMe2Cl2
(1.71 g, 7.80 mmol). Yield: 2.29 g, 76%. MS electron impact
(m/e (relative intensity)): 392 (1) [M+], 377 (9) [M+ꢀMe], 270
(100) [M+ꢀC5H4But], 241 (94) [M+ꢀC5H4But, ꢀ2 · Me].
Anal. Calc. for C20H32Sn: C, 61.41; H, 8.25. Found: C,
61.01; H, 8.20%.
R = H (11), SiMe3 (12)
M= Zr (a); Nb (b)
3. Conclusions
In this paper we have reported the synthesis and charac-
terization of new tin bridged ansa-bis(cyclopentadiene)
compounds. The molecular structures of two of the com-
pounds have been described. The transmetalation reaction
with zirconium or niobium tetrachloride proved to be suc-
cessful and yielded the metallocene dichloride complexes.
4.5. Synthesis of Me2Sn(C5H4{SiMe3}-1)2 (4)
The preparation of 4 was carried out in an identical man-
ner to 1. Li(C5H4SiMe3) (2.00 g, 13.87 mmol) and SnMe2Cl2
(1.52 g, 6.93 mmol). Yield: 2.38 g, 81%. MS electron impact
(m/e (relative intensity)): 424 (2) [M+], 409 (39) [M+ꢀMe],
286 (100) [M+ꢀC5H4SiMe3], 256 (77) [M+ꢀC5H4SiMe3,
ꢀ2 · Me]. Anal. Calc. for C18H32Si2Sn: C, 51.07; H, 7.62.
Found: C, 51.09; H, 7.58%.
4. Experimental
4.1. Materials and procedures
All reactions were performed using standard Schlenk
tube techniques in an atmosphere of dry nitrogen. Solvents
were distilled from the appropriate drying agents and
degassed before use. SnMe2Cl2, Na(C5H4Pri), Li(C5H4But)
and ZrCl4, were purchased from Aldrich and used without
further purification. Na(C5H5) [15], Li(C5H4SiMe3) [16],
Li(C5Me4H) [10a] and Li(C5Me4SiMe3) [13f] were prepared
as previously reported. 1H, 13C{1H} and 119Sn NMR spectra
were recorded on a Varian Mercury FT-400 spectrometer
and referenced to the residual deuterated solvent. Microa-
nalyses were carried out with a Perkin–Elmer 2400 microan-
alyzer. Mass spectroscopic analyses were preformed on a
Hewlett-Packard 5988A (m/z 50–1000) instrument.
4.6. Synthesis of Me2Sn(C5Me4H-1)2 (5)
Thepreparationof5wascarriedoutinanidenticalmanner
to1. Li(C5Me4H)(2.00 g, 15.60 mmol)and SnMe2Cl2 (1.71 g,
7.80 mmol). Yield: 2.22 g, 73%. MS electron impact (m/e (rel-
ative intensity)): 392 (7) [M+], 271 (100) [M+ꢀC5Me4H], 241
(77) [M+ꢀC5Me4H, ꢀ2 · Me]. Anal. Calc. for C20H32Sn: C,
61.41; H, 8.25. Found: C, 61.30; H, 8.21%.
4.7. Synthesis of Me2Sn(C5Me4{SiMe3}-1)2 (6)
The preparation of 6 was carried out in an identical man-
ner to 1. Li(C5Me4SiMe3) (2.00 g, 9.98 mmol) and SnMe2Cl2
(1.10 g, 4.99 mmol). Yield: 1.82 g, 68%. MS electron impact
(m/e (relative intensity)): 536 (1) [M+], 343 (100)
4.2. Synthesis of Me2Sn(C5H4Me-1)2 (1)
[M+ꢀC5Me4SiMe3],
313
(59)
[M+ꢀC5Me4SiMe3,
Li(C5H4Me) (2.00 g, 23.24 mmol) was added to a solution
of SnMe2Cl2 (2.55 g, 11.62 mmol) in THF (50 ml) at ꢀ78 ꢁC.
The reaction mixture was allowed to reach room tempera-
ture and stirred for 16 h. Solvent was removed by applying
ꢀ2 · Me], 73 (94) [M+ꢀMe2Sn(C5Me4SiMe3)(C5Me4)].
Anal. Calc. for C26H48Si2Sn: C, 58.31; H, 9.03. Found: C,
57.79; H, 8.92%.

3062
S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
4.8. Synthesis of [Zr(C5H4Me)2Cl2] (7a)
The resulting suspension was filtered and the filtrate con-
centrated (10 ml) to yield the title compound as a crystal-
line solid (0.78 g, 74%). Anal. Calc. for C12H14Cl2Nb: C,
44.75; H, 4.38. Found: C, 44.67; H, 4.35%.
Me2Sn(C5H4Me-1)2 (1) (1.00 g, 3.26 mmol) was added
to ZrCl4 (0.76 g, 3.26 mmol) in toluene (50 ml). The reac-
tion mixture was then stirred, under reflux, for 24 h. The
resulting suspension was evaporated and hexane (100 ml)
added. The mixture was filtered and the filtrate concen-
trated (10 ml). The title compound was obtained, as a crys-
talline solid, on cooling this solution (0.70 g, 67%). Anal.
Calc. for C12H14Cl2Zr: C, 44.99; H, 4.40. Found: C,
44.81; H, 4.36%.
4.15. Synthesis of [Nb(C5H4Pri)2Cl2] (8b)
The preparation of 8b was carried out in an identical
manner to 7b. Me2Sn(C5H4Pri-1)2 (2) (1.00 g, 2.75 mmol)
and [NbCl4(THF)2] (1.02 g, 2.75 mmol). Yield: 0.84 g,
81%. Anal. Calc. for C16H22Cl2Nb: C, 50.82; H, 5.86.
Found: C, 50.55; H, 5.79%.
4.9. Synthesis of [Zr(C5H4Pri)2Cl2] (8a)
4.16. Synthesis of [Nb(C5H4But)2Cl2] (9b)
The preparation of 8a was carried out in an identical
manner to 7a. Me2Sn(C5H4Pri-1)2 (2) (1.00 g, 2.75 mmol)
and ZrCl4 (0.64 g, 2.75 mmol). Yield: 0.60 g, 58%. Anal.
Calc. for C16H22Cl2Zr: C, 51.04; H, 5.89. Found: C,
50.89; H, 5.83%.
The preparation of 9b was carried out in an identical
manner to 7b. Me2Sn(C5H4But-1)2 (3) (1.00 g, 2.56 mmol)
and [NbCl4(THF)2] (0.94 g, 2.56 mmol). Yield: 0.86 g,
83%. Anal. Calc. for C18H26Cl2Nb: C, 53.22; H, 6.45.
Found: C, 53.01; H, 6.42%.
4.10. Synthesis of [Zr(C5H4But)2Cl2] (9a)
4.17. Synthesis of [Nb(C5H4SiMe3)2Cl2] (10b)
The preparation of 9a was carried out in an identical
manner to 7a. Me2Sn(C5H4But-1)2 (3) (1.00 g, 2.56 mmol)
and ZrCl4 (0.60 g, 2.56 mmol). Yield: 0.65 g, 63%. Anal.
Calc. for C18H26Cl2Zr: C, 53.44; H, 6.48. Found: C,
53.15; H, 6.46%.
The preparation of 10b was carried out in an identical
manner to 7b. Me2Sn(C5H4SiMe3-1)2 (4) (1.00 g, 2.36 mmol)
and [NbCl4(THF)2] (0.88 g, 2.36 mmol). Yield: 0.79 g, 77%.
Anal. Calc. for C16H26Cl2NbSi2: C, 43.84; H, 5.98. Found:
C, 43.81; H, 5.96%.
4.11. Synthesis of [Zr(C5H4SiMe3)2Cl2] (10a)
4.18. Synthesis of [Nb(C5Me4H)2Cl2] (11b)
The preparation of 10a was carried out in an identical
manner to 7a. Me2Sn(C5H4SiMe3-1)2 (4) (1.00 g, 2.36 mmol)
and ZrCl4 (0.55 g, 2.36 mmol). Yield: 0.68 g, 66%. Anal.
Calc. for C16H26Cl2Si2Zr: C, 44.01; H, 6.00. Found: C,
43.92; H, 6.00%.
The preparation of 11b was carried out in an identical
manner to 7b. Me2Sn(C5Me4H-1)2 (5) (1.00 g, 2.56 mmol)
and [NbCl4(THF)2] (0.94 g, 2.56 mmol). Yield: 0.85 g,
83%. Anal. Calc. for C18H26Cl2Nb: C, 53.22; H, 6.45.
Found: C, 52.94; H, 6.39%.
4.12. Synthesis of [Zr(C5Me4H)2Cl2] (11a)
4.19. Synthesis of [Nb(C5Me4SiMe3)2Cl2] (12b)
The preparation of 11a was carried out in an identical
manner to 7a. Me2Sn(C5Me4H-1)2 (5) (1.00 g, 2.56 mmol)
and ZrCl4 (0.60 g, 2.56 mmol). Yield: 0.60 g, 58%. Anal.
Calc. for C18H26Cl2Zr: C, 53.44; H, 6.48. Found: C,
53.27; H, 6.43%.
The preparation of 12b was carried out in an identical
manner to 7a. Me2Sn(C5Me4{SiMe3}-1)2 (6) (1.00 g,
1.86 mmol) and [NbCl4(THF)2] (0.69 g, 1.86 mmol). Yield:
0.63 g, 61%. Anal. Calc. for C24H42Cl2NbSi2: C, 52.36; H,
7.69. Found: C, 52.00; H, 7.60%.
4.13. Synthesis of [Zr(C5Me4SiMe3)2Cl2] (12a)
4.20. X-ray structure determinations of Me2Sn(C5Me4H-1)2
(5) and Me2Sn(C5Me4{SiMe3}-1)2 (6)
The preparation of 12a was carried out in an identical
manner to 7a. Me2Sn(C5Me4{SiMe3}-1)2 (6) (1.36 g,
2.55 mmol) and ZrCl4 (0.59 g, 2.55 mmol). Yield: 0.95 g,
68%. Anal. Calc. for C24H42Cl2Si2Zr: C, 52.52; H, 7.71.
Found: C, 52.23; H, 7.62%.
Data were collected on a Bruker SMART CCD-based
diffractometer operating at 50 kV and 100 mA, using
x/2h scan-technique. The structure was solved using the
SHELXS-97 software by direct methods and refined by full-
matrix least-squares methods on F2 [17,18]. All non-hydro-
gen atoms were refined anisotropically. Hydrogen atoms
were included in calculated positions, and refined in the rid-
ing mode. Weights were optimized in the final cycles. Crys-
tallographic data are given in Table 7.
4.14. Synthesis of [Nb(C5H4Me)2Cl2] (7b)
Me2Sn(C5H4Me-1)2 (1) (1.00 g, 3.26 mmol) was added
to [NbCl4(THF)2] (1.23 g, 3.26 mmol) in toluene (50 ml).
The reaction mixture was stirred, under reflux, for 24 h.

S. Go´mez-Ruiz et al. / Journal of Organometallic Chemistry 692 (2007) 3057–3064
[3] A. Togni, Metallocenes, Wiley-VCH, Weinheim, 1998.
3063
Table 7
Crystal data and structure refinement for 5 and 6
[4] S. Badhuri, D. Mukehs, Homogeneous Catalysis: Mechanisms and
Industrial Applications, John Wiley & Sons Inc., New York, 2000.
[5] J. Hagen, Industrial Catalysis: A Practical Approach, Wiley VCH,
Weinheim, 1999.
5
6
Formula
Fw
C20H32Sn
391.15
C26H48Si2Sn
535.51
[6] (a) see for example N. Sweeney, W.M. Gallagher, H. Muller-Bunz,
¨
T (K)
Crystal system
100(2)
Triclinic
100(2)
Monoclinic
C2/c
14.9483(2)
9.5901(1)
20.2146(2)
C. Pampillon, K. Strohfeldt, M. Tacke, J. Inorg. Biochem. 100
(2006) 1479;
(b) C. Pampillon, N.J. Sweeney, K. Strohfeldt, M. Tacke, Inorg.
Chim. Acta 359 (2006) 3969;
(c) R. Meyer, S. Brink, E.J.C. van Rensburg, J. Organomet. Chem.
690 (2005) 117.
ꢀ
Space group
P1
˚
a (A)
8.7564(1)
13.4869(1)
16.8979(2)
82.884(1)
86.808(1)
75.670(1)
1917.95(3)
4
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
[7] (a) H.P. Fritz, C.G. Kreiter, J. Organomet. Chem. 1 (1964) 323;
(b) V.N. Torocheshnikov, A.P. Tupciauskas, Y.A. Ustynyuk, J.
Organomet. Chem. 81 (1974) 58.
[8] (a) P. Jutzi, B. Hielscher, Organometallics 5 (1986) 2511;
(b) W.A. Herrmann, M.J.A. Morawietz, H.-F. Herrmann, F. Kueber,
J. Organomet. Chem. 509 (1996) 115;
103.149(1)
3
˚
V (A )
2821.90(6)
4
1.260
8.067
1128
Z
Dcalc (g cmꢀ3
)
1.355
10.515
808
l (mmꢀ1
F(000)
)
(c) I.E. Nifant’ev, M.V. Borzov, A.V. Churakov, Organometallics 11
(1992) 3942.
Crystal dimensions (mm)
h Range (ꢁ)
0.30 · 0.25 · 0.20 0.35 · 0.30 · 0.12
[9] (a) M. Huttenhofer, M.-H. Prosenc, U. Rief, F. Schaper, H.H.
¨
2.64–70.47
4.49–70.55
Brintzinger, Organometallics 15 (1996) 4816;
(b) M. Huttenhofer, F. Schaper, H.-H. Brintzinger, J. Organomet.
¨
Chem. 660 (2002) 85;
(c) I.E. Nifant’ev, K.A. Butakov, Z.G. Aliev, I.F. Urazowski,
Metalloorg. Khim. 4 (1991) 1265;
(d) M. Huttenhofer, F. Schaper, H.H. Brintzinger, Angew. Chem.,
¨
Int. Ed. 37 (1998) 2268;
(e) M. Huttenhofer, F. Schaper, H.-H. Brintzinger, J. Organomet.
¨
Chem. 660 (2002) 85;
(f) N.B. Ivchenko, P.V. Ivchenko, I.E. Nifant’ev, Russ. Chem. Bull.
49 (2000) 508;
(g) M. Huttenhofer, M.-H. Prosenc, U. Rief, F. Schaper, H.H.
¨
Brintzinger, Organometallics 15 (1996) 4816;
(h) P.J. Chirik, D.L. Zubris, L.J. Ackerman, L.M. Henling, M.W.
Day, J.E. Bercaw, Organometallics 22 (2003) 172.
hkl Ranges
ꢀ10 6 h 6 10,
ꢀ16 6 k 6 16,
ꢀ20 6 l 6 20
6613/399
ꢀ18 6 h 6 16,
ꢀ11 6 k 6 11,
ꢀ24 6 l 6 24
2595/229
Data/parameters
Goodness-of-fit on F2
Final R indices [I > 2r(I)]
1.040
1.056
R1 = 0.0445,
wR2 = 0.1181
R1 = 0.0479,
wR2 = 0.1214
2.137/ꢀ2.081
R1 = 0.0286,
wR2 = 0.0721
R1 = 0.0287,
wR2 = 0.0722
0.951/ꢀ0.896
R indices (all data)
Largest difference in peak and
ꢀ3
˚
hole (e A
)
P
5. Supplementary material
P
P
P
R1 = iFoj ꢀ jFci/ jFoj; wR2 = [ [w(F2o ꢀ Fc2)2]/ [w(Fo2)2]]0.5
.
´
[10] (a) A. Antinolo, I. Lopez-Solera, I. Orive, A. Otero, S. Prashar,
˜
´
A.M. Rodrıguez, E. Villasenor, Organometallics 20 (2001) 71;
˜
´
(b) A. Antinolo, I. Lopez-Solera, A. Otero, S. Prashar, A.M.
˜
CCDC 634216 and 634217 contain the supplementary
crystallographic data for 5 and 6. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallo-
graphic Data Centre, 12 Union Road, Cambridge CB2
1EZ, UK; fax: (+44) 1223-336-033; or e-mail: deposit@
ccdc.cam.ac.uk.
´
Rodrıguez, E. Villasenor, Organometallics 21 (2002) 2460;
(c) A. Antinolo, M. Fajardo, S. Gomez-Ruiz, I. Lopez-Solera, A. Otero,
S. Prashar, A.M. Rodrıguez, J. Organomet. Chem. 683 (2003) 11;
(d)A. Antinolo, M. Fajardo, S. Gomez-Ruiz, I. Lopez-Solera, A. Otero,
˜
S. Prashar, Organometallics 23 (2004) 4062;
(e) S. Go´mez-Ruiz, T. Ho¨cher, S. Prashar, E. Hey-Hawkins, Organo-
metallics 24 (2005) 2061;
˜
´
´
˜
´
´
´
´
(f)S. Gomez-Ruiz, S. Prashar, M. Fajardo, A. Antinolo, A. Otero, M.A.
˜
Maestro, V. Volkis, M.S. Eisen, C.J. Pastor, Polyhedron 24 (2005) 1298;
Acknowledgements
´
´
´
(g) A. Garces, Y. Perez, S. Gomez-Ruiz, M. Fajardo, A. Antinolo, A.
˜
´
´
Otero, C.Lopez-Mardomingo,P.Gomez-Sal,S. Prashar,J.Organomet.
Chem. 691 (2006) 3652;
We gratefully acknowledge financial support from the
´
´
´
(h) S. Gomez-Ruiz, S. Prashar, L.F. Sanchez-Barba, D. Polo-Ceron, M.
´
Ministerio de Educacion
y Ciencia, Spain (Grants
Fajardo, A. Antinolo, A. Otero, M.A. Maestro, C.J. Pastor, J. Mol.
˜
Catal. A: Chem. 264 (2007) 260;
no. CTQ2005-07918-C02-02/BQU and CTQ2006-11845/
´
BQU). We would also like to thank Dr. Cesar Pastor (Uni-
´
´
(i)D. Polo-Ceron, S. Gomez-Ruiz, S. Prashar, M. Fajardo, A. Antinolo,
˜
´
versidad Autonoma de Madrid) for his assistance in the
A. Otero, I. Lo´pez-Solera, M.L. Reyes, J. Mol. Catal. A: Chem. 268
(2007) 264.
´
structural resolution of 5 and 6 and Carmen Force
[11] (a) S. Yamada, M. Sone, A. Yano, Jpn. Kokai Tokkyo Koho, 1992.
CODEN: JKXXAF JP 04359003 A2 19921211. Application: JP 91-
159855 19910605;
(CAT, Universidad Rey Juan Carlos) for her aid in the
measurement of the 119Sn NMR spectra.
(b) H. Wiesenfeldt, A. Reinmuth, E. Barsties, K. Evertz, H.-H.
Brintzinger, J. Organomet. Chem. 369 (1989) 359;
(c) P. Jutzi, R. Dickbreder, Chem. Ber. 119 (1986) 1750;
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