Conversion of Alkyltantalum Chlorides to Fluorides Using Trimethyltin Fluoride as a Fluorinating Agent. Crystal Structures of (p-MeC6H4CH2)3TaF2, (Me3SnCl.Me3SnF.TaF5)n, (Me3Si)2CHTaCl4

Article abstract of DOI:10.1021/om980768g

The reactions of alkyltantalum chlorides with trimethyltin fluoride were found to be highly dependent on the number of organic ligands on tantalum as well as on the electronic and the steric nature of the substituants. The synthesis of trialkyltantalum difluorides of general formula (RCH₂)₃TaF₂ (R = Ph, 1; R = p-Tol, 2; R = Me₃Si, 3) and the first example of the alkyltantalum tetrafluoride (Me₃Si)₂CHTaF₄ (8) are reported. The compounds (p-MeC₆H₄-CH₂)₃TaF₂, (Me₂SnCl.Me₃SnFTaF₅)_n (Me₃Si)₂CHTaCl₄, {(Me₃Si)₂CHTaCl₄(Me₃Si) ₂CH]₂Ta₂-Cl₆μ₂-O)}, and (Me₃Si)₂CHTaF₄ respectively have been characterized by single-crystal X-ray structural analysis.

Full text of DOI:10.1021/om980768g

8
32
Organometallics 1999, 18, 832-836
Con ver sion of Alk ylta n ta lu m Ch lor id es to F lu or id es
Usin g Tr im eth yltin F lu or id e a s a F lu or in a tin g Agen t.
Cr ysta l Str u ctu r es of (p-MeC H CH ) Ta F ,
6
4
2 3
2
(
Me Sn Cl‚Me Sn F ‚Ta F ) , (Me Si) CHTa Cl ,
3
3
5 n
3
2
4
{
(Me Si) CHTa Cl ‚[(Me Si) CH] Ta Cl (µ -O)}, a n d
3
2
4
3
2
2
2
6
2
†
(
Me Si) CHTa F
3
2
4
Olexandr I. Guzyr, Mark Schormann, J u¨ rgen Schimkowiak, Herbert W. Roesky,*
Christopher Lehmann, Mrinalini G. Walawalkar, Ramaswamy Murugavel,
Hans-Georg Schmidt, and Mathias Noltemeyer
Institut f u¨ r Anorganische Chemie der Universit a¨ t G o¨ ttingen, Tammannstrasse 4,
D-37077 G o¨ ttingen, Germany
Received September 14, 1998
The reactions of alkyltantalum chlorides with trimethyltin fluoride were found to be highly
dependent on the number of organic ligands on tantalum as well as on the electronic and
the steric nature of the substituents. The synthesis of trialkyltantalum difluorides of general
formula (RCH
alkyltantalum tetrafluoride (Me
CH TaF , (Me SnCl‚Me SnF‚TaF
Cl (µ -O)}, and (Me Si) CHTaF
structural analysis.
2
)
3
TaF
2
(R ) Ph, 1; R ) p-Tol, 2; R ) Me
Si) CHTaF (8) are reported. The compounds (p-MeC
2
, (Me Si) CHTaCl , {(Me Si) CHTaCl Si) CH] Ta
3
Si, 3) and the first example of the
3
2
4
6
H
4
-
-
2
)
3
2
3
3
5
)
n
3
2
4
3
2
4
‚[(Me
3
2
2
6
2
3
2
4
respectively have been characterized by single-crystal X-ray
In tr od u ction
The chemistry of alkyltantalum chlorides has been
Sch em e 1
the subject of numerous investigations due to their
ability to act as precursors for the preparation of
alkylidene and alkylidyne compounds in reactions using
1
alkylmagnesium or alkyllithium reagents. In contrast,
the number of corresponding alkyltantalum fluorides is
limited. However, (Me3CCH2)3TaF2 was obtained by
Schrock et al. in low yield in an attempt to prepare
+
-
[
(Me3CCH2)4Ta] BF4 by the reaction of (Me3CCH2)3-
1
(RCH ) TaCl (R ) Ph, p-Tol, Me Si) in dichloromethane
Ta(dCHCMe3) with HBF4.
2 3
2
3
or THF as a solvent was found to be a convenient route
to high-yield synthesis of the corresponding difluorides,
after sublimation, distillation, or recrystallization from
In our previous work we developed general methods
for the preparation of fluorine-containing compounds of
main group elements and early transition metals using
2
3 2
pentane (Scheme 1). Using Me TaCl as a starting
organotin fluorides as fluorinating reagents. Due to our
material leads to the formation of a mixture of non-
characterizable and poorly soluble products. This may
be due to the low shielding of the tantalum atom in Me3-
TaCl2 that leads to side reactions, such as the substitu-
tion of the methyl groups by fluorine. A similar methyl
group substitution reaction has already been observed
and used as a synthetic method for the preparation of
the aminoaluminum difluorides from the corresponding
interest in the preparation and chemistry of organome-
tallic fluorides, we decided to explore convenient syn-
thetic routes to the different types of alkyltantalum
fluorides by halogen exchange reactions using tri-
methyltin fluoride as a fluorine source.
Resu lts a n d Discu ssion
Reaction of Tr im eth yltin Flu or ide with Tr ialkyl-
t a n t a lu m Dich lor id es. Reaction of Me3SnF with
3
dimethylaminoallanes and Me3SnF.
Compounds 1-3 are colorless or yellow crystalline
solids, extremely sensitive to moisture and air, and very
soluble in aromatic or hydrocarbon solvents. In contrast
to the thermally unstable starting materials, the di-
fluorides 1-3 show remarkable thermal stability and
†
Dedicated to Professor U. Wannagat on the occasion of his 75th
birthday.
(1) (a) Nugent, W. A.; Mayer, J . M. Metal-Ligand Multiple Bonds.
The Chemistry of Transition Metal Complexes Containing Oxo, Nitrido,
Imido, Alkylidene, or Alkylidyne Ligands; J ohn Wiley & Sons: New
York, 1988, and references therein. (b) Schrock, R. R.; Fellmann, J . D.
J . Am. Chem. Soc. 1978, 100, 3359. (c) Li, L.; Hung, M.; Xue, Z. J .
Am. Chem. Soc. 1995, 117, 12746.
(3) (a) Waezsada, S. D.; Liu, F.-Q.; Murphy, E. F.; Roesky, H. W.;
Teichert, M.; Us o´ n, I.; Schmidt, H.-G.; Albers, T.; Parisini, E.; Nolte-
meyer, M. Organometallics 1997, 16, 1260. (b) Schnitter, C.; Klimek,
K.; Roesky, H. W.; Albers, T.; Schmidt, H.-G.; R o¨ pken, C.; Parisini, E.
Organometallics 1998, 17, 2249.
(2) (a) Herzog, A.; Liu, F.-Q.; Roesky, H. W.; Demsar, A.; Keller, K.;
Noltemeyer, M.; Pauer, F. Organometallics 1994, 13, 1251. (b) Roesky,
H. W.; Herzog, A.; Keller, K. Z. Naturforsch. B 1994, 49, 981. (c)
Roesky, H. W.; Keller, K. J . Fluor. Chem. 1998, 89, 3.
1
0.1021/om980768g CCC: $18.00 © 1999 American Chemical Society
Publication on Web 02/09/1999

Conversion of Alkyltantalum Chlorides to Fluorides
Organometallics, Vol. 18, No. 5, 1999 833
1H NMR and mass spectroscopic investigations of the
resulting solids indicated a complex mixture of products.
In contrast to the fluorination of trialkyltantalum
dichlorides, the trichloride reaction resulted in partial
cleavage of the Ta-C bonds. This phenomenon was also
observed in the reaction of (Me3SiCH2)TaCl4 with excess
Me3SnF, which reacts in dichloromethane in a molar
ratio of 1:5 to afford colorless crystals of (Me3SnCl‚Me3-
SnF‚TaF5)n (4) in a 14% yield.
Compound 4 was characterized by an X-ray structural
analysis. It crystallizes in the orthorombic space group
(
Pnma) with four molecules in the unit cell. The
monomer (Figure 3) consists of one TaF6 octahedron and
two Me3Sn groups connected by a chlorine atom. The
geometry around the tin atoms is trigonal bipyramidal
with three methyl groups occupying equatorial posi-
tions, with the two axial positions being occupied by
bridging chlorine and fluorine atoms. The molecule of
4 resides on a crystallographic mirror plane. The Ta(1)-
F(4)-Sn(2) angle of 179.9° shows that the TaF6 octa-
hedron is bonded to a tin pyramid in a linear fashion.
6 4 2 3 2
F igu r e 1. Molecular structure of (p-MeC H CH ) TaF in
the solid state.
can be stored for months at room temperature in an
inert atmosphere. No decomposition is observed upon
heating 1-3 for hours in toluene.
2
1
The spectral and analytical data for the difluorides
The Sn -Cl-Sn angle is bent (132.3°).
1
-3 are summarized in the Experimental Section.
The solid-state structure of 4 shows the formation of
layers with a Sn-F distance of 3.59(3) Å between the
chains and 2.54(9) Å within the chains.
1
9
Compounds 1-3 have F NMR spectral signals in the
low-field region (106-115 ppm) with characteristic
3
J (HF) coupling, indicating a high covalent contribution
Syn th esis of (Me3Si)2CHTa Cl4 (5). In previous
investigations it was shown that compounds containing
the (Me3Si)2CH ligand generally give well-defined and
1
to the Ta-F bonds. The H NMR spectra show signals
for the CH2 groups in the range 1.1-2.3 ppm, with
3
characteristic J (FH) coupling.
6
very soluble crystalline products. Consequently we
Compound 2 was characterized by a single-crystal
structure analysis (Figure 1). Suitable single crystals
of 2 were obtained from a pentane solution at -20 °C.
To the best of our knowlegde, 2 is the first example of
a structurally characterized trialkyltantalum difluoride.
The crystal data of 2 are given in Table 1, and selected
bond lengths and angles in Table 2. The central TaF2C3
core of 2 in the solid state exhibits a trigonal-bipyra-
midal arrangement with two F atoms in the axial and
three p-Tol groups in equatorial positions. The Ta-F
bond lengths (1.877(3) and 1.924(3) Å) are comparable
to the distances between Ta and terminal fluorine atoms
prepared the monosubstituted tantalum halides (Me3-
Si)2CHTaX4 (X ) Cl, 5; X ) Br, 6) by the reaction of
TaCl5 and TaBr5, respectively, with [(Me3Si)2CH]2Zn in
n-hexane (Scheme 2). The yield of the tetrachloride 5
(65%) was higher than that of the corresponding tetra-
bromide 6 (30%). Analytical and spectroscopic data for
compounds 5 and 6 are given in the Experimental
Section.
In an attempt to crystallize (Me3Si)2CHTaCl4 from
n-hexane at -30 °C during a three month period, partial
hydrolysis occurred to give {(Me3Si)2CHTaCl4‚[(Me3-
Si)2CH]2Ta2Cl6(µ2-O)} (7), which was characterized by
an X-ray structural investigation. The structure of 7 is
shown in Figure 4, and selected bond lengths and angles
are given in Table 4.
Complex 7 crystallizes in the triclinic P 1h space group
with (Me3Si)2CHTaCl4 × 0.5[(Me3Si)2CH]2Ta2Cl6(µ2-O)
per unit cell. The tantalum has a trigonal bipyramidal
environment with the organic ligands in equatorial
positions.
Crystals of pure 5 suitable for X-ray studies were
grown from n-hexane at -30 °C. The molecular struc-
ture of 5 is shown in Figure 5, and selected bond
distances and angles are given in Table 5. Compound 5
crystallizes in the P 1h space group with four molecules
per unit cell (two independent molecules in the asym-
metric unit). The tantalum center has a trigonal-
bipyramidal environment, with the organic ligands in
equatorial positions and two different Ta-Cl bond
distances (Ta-Cleq 2.296(7) Å, Ta-Clax 2.313(7) Å).
5
4
found for [(η -C5Me5)TaF4]‚2AsF3. The Ta-CH2 dis-
tances (2.149(5)-2.172(5) Å) are in good agreement with
those observed for Ta(OAr)2(CH2Ph)3 and Ta(CH2C6H4-
5
Me-p)5. The Ta-CH2-C angles in 2 (range 95.1-98.3°)
are significantly smaller than the “normal” M-C-C
bond angles (112°). Related to this, the distances
between the carbon atoms of the aromatic rings bonded
to the methylene carbon and the metal (2.713-2.811
Å) are smaller than expected. As a consequence, in the
solid state 2 shows a “propeller-like”configuration (Fig-
ure 2). A comparable phenomenon was previously
observed for Ta(OAr)2(CH2Ph)3 and Ta(CH2C6H4Me-p)5,
where, however, only one of the benzyl ligands shows a
smaller angle (90.4-94.8 Å) at the R-carbon atom,
whereas the others fall in the normal range (108.4-
25.7°).5
1
All attempts to obtain dialkyltantalum trifluorides
(
RCH2)2TaF3 (R ) Ph, p-MeC6H4, Me3Si) using the
corresponding chlorides and Me3SnF were unsuccessful.
(
4) Roesky, H. W.; Schrumpf, F.; Noltemeyer, M. J . Chem Soc.,
Dalton Trans. 1990, 713.
5) (a) Chamberlain, L. R.; Rothwell, I. P.; Folting, K.; Huffman, J .
(6) (a) Cowley, A. H.; Lasch, J . G.; Norman, N. C.; Pakulski, M.;
Whittlesey, B. R. Chem. Commun. 1983, 881. (b) Uhl, W. Z. Natur-
forsch. B 1988, 43, 1113. (c) Uhl, W.; Layh, M.; Hildenbrand, T. J .
Organomet. Chem. 1989, 364, 289. (d) Flynn, K. M.; Olmstead, M. M.;
Power, P. P. J . Am. Chem. Soc. 1983, 105, 2085.
(
C. J . Chem. Soc., Dalton Trans. 1987, 155. (b) Piersol, C. J .; Profilet,
R. D.; Fanwick, P. E.; Rothwell, I. P. Polyhedron 1993, 12, 1779.

8
34 Organometallics, Vol. 18, No. 5, 1999
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p ou n d s 2, 4, 5, 7, a n d 8
Guzyr et al.
2
4
5
7
8
empirical formula
C
24
H
27
F
2
Ta
C
6
H
18ClF
6
Sn
2
Ta
C
7
H
19Cl
4
Si
2
Ta
C
7
H
0
19Cl
4
Si
H
2
Ta +
4 2
OSi Ta
14 38 8 4 2
C H F Si Ta
.5C14
38Cl
6
fw
534.41
yellow
203(2)
657.98
colorless
200(2)
0.9 × 0.6 × 0.6
orthorombic
Pnma
22.136(4)
10.036(2)
7.5621(15)
90
482.15
yellow
203(2)
0.8 × 0.8 × 0.6
triclinic
P1h
9.046(2)
13.477(3)
14.581(3)
66.54(3)
82.71(3)
79.36(3)
1599.8(5)
4
2.002
7.657
920
3.55-22.47
5287, 4120
(Rint ) 0.0725)
0.0435, 0.1116
0.0445, 0.1168
1.125
482.16 + 0.5 × 909.41
832.70
colorless
203(2)
color of crystal
temp (K)
cryst size (mm)
cryst syst
space group
a (Å)
yellow
133(2)
0.7 × 0.4 × 0.4
0.5 × 0.4 × 0.4
0.8 × 0.3 × 0.3
monoclinic
triclinic
monoclinic
P2
1
/n
P1h
8.990(3)
13.370(3)
13.668(3)
89.77(3)
76.56(3)
79.18(3)
1568.1(7)
2
1.984
1
P2 /c
6.413(2)
14.390(5)
23.593(9)
90
96.05(2)
90
2165.0(13)
4
1.640
5.099
1048
3.52-25.11
5527, 3839
6.3858(13)
24.935(5)
17.406(4)
90
93.63(3)
90
2766.0(10)
4
2.000
b (Å)
c (Å)
R (deg)
â (deg)
90
90
γ (deg)
cell vol (Å)
Z
1680.0(6)
4
2.601
9.640
1192
3.68-22.52
3605, 1167
(Rint ) 0.1009)
0.0283, 0.0769
0.0292, 0.0775
1.183
F
c
(g mm-3)
-
1
µ (mm
F(000)
θ range (deg)
)
7.727
894
8.133
1584
2
2.14-25.00
20 190, 5513
(Rint ) 0.0362)
0.0275, 0.0654
0.0333, 0.0667
1.101
3.57-22.46
3587, 3544
(Rint ) 0.1115)
0.0526, 0.1485
0.0561, 0.1534
1.233
no. of data measd, unique
(Rint ) 0.0191)
R, wR2b (I > 2σ(I))
a
0.0315, 0.0776
0.0378, 0.0868
1.098
R, wR2 (all data)
goodness of fit, S c
no. of refined params
247
1.029/-1.118
93
266
3.471/-2.535
263
1.675/-1.451
266
2.969/-1.342
largest diff peak/hole (e Å-3)
1.648/-0.885
a
R ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) [∑w(Fo2 - Fc ) ]/[∑w(Fo ) ]1/2. c S ) [∑w(Fo2 - Fc ) ]/[∑(n - p)]1/2.
b
2
2
2
2
2
2
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(
6 4 2 3 2
d eg) for (p-MeC H CH ) Ta F (2)
Ta(1)-F(1)
Ta(1)-F(2)
Ta(1)-C(1)
1.877(3)
1.924(3)
2.149(5)
2.151(5)
2.172(5)
2.784(5)
2.713(5)
2.811(5)
F(1)-Ta(1)-C(11)
F(2)-Ta(1)-C(11)
C(1)-Ta(1)-C(11)
F(1)-Ta(1)-C(21)
F(2)-Ta(1)-C(21)
C(1)-Ta(1)-C(21)
C(11)-Ta(1)-C(21)
C(2)-C(1)-Ta(1)
C(12)-C(11)-Ta(1)
C(22)-C(21)-Ta(1)
88.9(2)
91.9(2)
120.2(2)
88.3(2)
89.8(2)
119.4(2)
120.4(2)
98.3(3)
95.1(3)
98.3(4)
Ta(1)-C(11)
Ta(1)-C(21)
Ta(1)-C(2)
Ta(1)-C(12)
Ta(1)-C(22)
F(1)-Ta(1)-F(2)
F(1)-Ta(1)-C(1)
F(2)-Ta(1)-C(1)
178.08(14)
90.1(2)
90.9(2)
F igu r e 3. Molecular structure of 4 in the solid state.
Sch em e 2
resulted in the formation of the corresponding tetrafluo-
ride 8 as a colorless crystalline product in a 52% yield
after sublimation (Scheme 3). To the best of our know-
ledge, 8 is the first example of an alkyltantalum
tetrafluoride.
Spectroscopic and analytical data for 8 are given in
1
9
the Experimental Section. The F NMR of 8 in dichlo-
romethane at room temperature shows a broad signal
(81.5 ppm), indicative of dynamic processes. At -95 °C,
three signals appeared (123, 103, and -29 ppm) with
the correct integration of 1:2:1. Thus, in solution at -95
°
C three types of fluorine atoms can be observed (two
kinds of terminal, one bridging), in agreement with the
solid-state structure (vide infra).
Compound 8 was characterized by single-crystal X-ray
diffraction analysis. The molecular structure of 8 is
shown in Figure 6, and selected bond lengths and angles
are listed in Table 6. Compound 8 crystallizes in the
monoclinic space group (P21/c) with two molecules in
the unit cell. Each tantalum center has an octahedral
environment. The molecules within the crystal are found
F igu r e 2. “Propeller-like” configuration of 2 in the solid
state (space-filling model).
Con ver sion of 5 to (Me3Si)2CHTa F 4 Usin g Me3Sn F .
The reaction of 5 with trimethyltin fluoride (in a molar
ratio 1:4) at room temperature in dichloromethane

Conversion of Alkyltantalum Chlorides to Fluorides
Organometallics, Vol. 18, No. 5, 1999 835
3 2 4
F igu r e 5. Two molecules of (Me Si) CHTaCl (5) in the
asymmetric unit.
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
d eg) for 5 (a ver a ge)
(
F igu r e 4. Crystal structure of 7 in the solid state.
Hydrogen atoms are omitted for clarity.
Ta(1)-C(1), Ta(2)-C(2)
2.046(2)
2.299(7)
2.316(2)
2.293(7)
2.311(2)
165.01(5)
138.20(4)
111.6(7)
97.9(7)
Ta(1)-Cl(1), Ta(2)-Cl(7)
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
Ta(1)-Cl(2), Ta(2)-Cl(6)
Ta(1)-Cl(3), Ta(2)-Cl(5)
(
d eg) for 4
Ta(1)-Cl(4), Ta(2)-Cl(8)
Ta(1)-F(3)
1.840(8)
1.845(8)
1.861(5)
1.861(5)
1.894(7)
1.916(6)
2.514(7)
2.555(3)
2.562(2)
92.2(4)
91.2(2)
91.4(2)
91.2(2)
91.4(2)
176.3(4)
178.6(4)
89.2(4)
88.8(2)
120.2(3)
117.3(6)
F(1)-Ta(1)-F(4)
F(3)-Ta(1)-F(2)
F(5)-Ta(1)-F(2)
F(1A)-Ta(1)-F(2)
F(1)-Ta(1)-F(2)
F(4)-Ta(1)-F(2)
C(3)-Sn(2)-F(4)
C(1)-Sn(2)-F(4)
C(1A)-Sn(2)-F(4)
C(3)-Sn(2)-Cl(1)
C(1)-Sn(2)-Cl(1)
C(1A)-Sn(2)-Cl(1)
F(4)-Sn(2)-Cl(1)
C(4)-Sn(1)-Cl(1)
C(2)-Sn(1)-Cl(1)
C(2A)-Sn(1)-Cl(1)
Sn(2)-Cl(1)-Sn(1)
Ta(1)-F(4)-Sn(2)
C(4)-Sn(1)-C(2A)
88.8(2)
89.0(4)
178.9(4)
88.6(2)
88.6(2)
89.7(3)
87.2(4)
82.3(3)
82.3(3)
100.0(3)
94.2(3)
94.2(3)
172.8(2)
97.7(3)
93.8(2)
93.8(2)
132.26(12)
180.0(3)
120.2(3)
Cl(2)-Ta(1)-Cl(4), Cl(6)-Ta(2)-Cl(8)
Cl(1)-Ta(1)-Cl(3), Cl(5)-Ta(2)-Cl(7)
C(1)-Ta(1)-Cl(1), C(2)-Ta(2)-Cl(7)
C(1)-Ta(1)-Cl(2), C(2)-Ta(2)-Cl(6)
C(1)-Ta(1)-Cl(3), C(2)-Ta(2)-Cl(5)
C(1)-Ta(1)-Cl(4), C(2)-Ta(2)-Cl(8)
Ta(1)-F(5)
Ta(1)-F(1A)
Ta(1)-F(1)
Ta(1)-F(4)
110.1(7)
97.0(2)
Ta(1)-F(2)
Sn(2)-F(4)
Sn(2)-Cl(1)
Sn(1)-Cl(1)
F(3)-Ta(1)-F(5)
F(3)-Ta(1)-F(1A)
F(5)-Ta(1)-F(1A)
F(3)-Ta(1)-F(1)
F(5)-Ta(1)-F(1)
F(1A)-Ta(1)-F(1)
F(3)-Ta(1)-F(4)
F(5)-Ta(1)-F(4)
F(1A)-Ta(1)-F(4)
C(4)-Sn(1)-C(2)
C(2)-Sn(1)-C(2A)
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
d eg) for 7
(
Ta(1)-O(1)
1.8813(6)
2.059(5)
Ta(2)-C(8)
2.021(5)
Ta(1)-C(1)
Ta(2)-Cl(4)
2.3060(17)
2.2938(15)
2.3390(17)
2.3048(15)
89.24(4)
F igu r e 6. Two molecules of 8, with bridging fluorine
atoms. Further interactions are omitted for clarity.
Ta(1)-Cl(1)
2.3353(16)
2.3100(15)
2.3362(16)
115.55(13)
128.17(4)
116.26(14)
88.80(6)
87.42(6)
168.44(6)
134.94(5)
Ta(2)-Cl(5)
Ta(1)-Cl(2)
Ta(2)-Cl(6)
Ta(1)-Cl(3)
Ta(2)-Cl(7)
Sch em e 3
O(1)-Ta(1)-C(1)
O(1)-Ta(1)-Cl(2)
C(1)-Ta(1)-Cl(2)
Cl(2)-Ta(1)-Cl(3)
Cl(7)-Ta(2)-Cl(6)
Cl(4)-Ta(2)-Cl(6)
Cl(5)-Ta(2)-Cl(7)
O(1)-Ta(1)-Cl(3)
Cl(2)-Ta(1)-Cl(1)
Cl(1)-Ta(1)-Cl(3)
C(8)-Ta(2)-Cl(5)
Si(3)-C(8)-Ta(2)
Cl(7)-Ta(2)-Cl(4)
86.77(6)
172.97(5)
112.01(14)
120.5(2)
Ta ble 6. Selected Bon d Len gth s (Å) a n d An gles
86.39(6)
(
d eg) for 8
Ta(1)-F(1)
Ta(1)-F(2)
Ta(1)-F(3)
Ta(1)-F(4)
Ta(1)-F(5)
Ta(1)-C(1)
F(3)-Ta(1)-F(1)
1.971(11)
1.860(11)
1.864(11)
1.867(11)
2.418(11)
2.05(2)
Ta(2)-F(5)-Ta(1)
F(2)-Ta(1)-F(3)
F(2)-Ta(1)-F(4)
F(6)-Ta(2)-F(5)
C(1)-Ta(1)-F(5)
F(8)-Ta(2)-F(5)
F(6)-Ta(2)-F(7)
141.0(5)
91.1(5)
151.1(5)
85.6(5)
171.4(6)
171.5(5)
148.6(5)
to be connected by bridging fluorine atoms. In agree-
1
9
ment with the F NMR spectrum in solution at low
temperatures, three types of fluorine atoms were found
in the solid state. The tantalum bridging fluorine bond
distances (2.42 Å) are significantly longer than the
corresponding distances of the nonbridging fluorines.
However they are longer (by about 0.2 Å) than those in
172.2(5)
ligands, thus accounting for the solubility of 8 in
nonpolar hydrocarbon solvents.
5
4
[
(η -C5Me5)TaF4]‚2AsF3. All terminal Ta-F bond lengths
are in the range 1.860(11)-1.867(11) Å. The C(1)-
Ta(1)-F(5) angle (171°) indicates a slight distortion of
the octahedral environment. The angle between two of
the octahedrons, Ta(1)-F(5)-Ta(2), is about 141°, which
leads to the formation of zigzag chains in the crystal of
Exp er im en ta l Section
Gen er a l Meth od s a n d Ma ter ia ls. All the reactions were
performed in deoxygenated argon or dinitrogen atmosphere
using glovebox and high-vacuum techniques. The starting
materials were prepared according to literature methods
were freshly sublimed or recrystallized prior to use. Aromatic,
7
and
8
. The inorganic centers are surrounded by hydrophobic

8
36 Organometallics, Vol. 18, No. 5, 1999
Guzyr et al.
hydrocarbon, and etherated solvents were dried over Na/K
alloy and vacuum transferred to the reaction flasks prior to
vacuo, and the oily residue crystallized to a colorless solid.
1
Yield: 1.1 g (14%). Mp: 65 °C. H NMR (CDCl
3
): 0.80 (s, 18H,
): 238.6
1
9
119
use. Dichloromethane was dried over CaH
2
and vacuum
CH
3
). F NMR (CDCl
3
): 44.72 (s). Sn NMR (CDCl
3
transferred prior to use. NMR spectra were recorded on Bruker
(s). IR: v 1715 w, 1621 w, 1261 w, 1250 w, 1201 w, 1097 w,
AM 200 and Bruker AM 250 instruments. Chemical shifts are
1017 w, 887 w, 851 w, 833 w, 795 m, 721 w, 701 w, 607 s, 584
1
reported in δ scale with reference to external SiMe
4
for H and
s, 557 s, 543 s, 425 m. EI MS (70 eV): m/e (%) [TaF
[Me SnCl], 200 (4), [Me SnCl - Me], 185 (100), [Me
(38). Anal. Calcd for C Sn Ta: C, 10.95; H, 2.76; Cl,
4
], 257 (5),
1
3
19
C and CCl
3
F for F nuclei. Mass spectra were obtained on
3
3
3
Sn], 165
Finnigan MAT system 8230 and a Varian MAT CH5 mass
spectrometer. FT-IR spectra were measured on a Bio-Rad
FTS-7 as Nujol mulls between CsI plates. Melting points were
obtained on a HWS-SG 3000 apparatus. Elemental analyses
were performed by the Analytical Laboratory of the Institute
6
H
18ClF
6
2
5.39; F, 17.33; Sn, 36.08. Found: C, 10.6; H, 2.9; Cl, 5.7; F,
17.5; Sn, 35.7.
P r ep a r a tion of (Me
TaCl (7.0 g, 19.5 mmol) in n-hexane (100 mL) was added
[(Me Si) CH] Zn (3.0 g, 7.8 mmol) dropwise at room temper-
ature. After complete addition, the reaction mixture was
stirred for an additional 8 h. The precipitate of ZnCl was
3 2 4
Si) CHTa Cl (5). To a suspension of
5
8
of Inorganic Chemistry, University of G o¨ ttingen.
3
2
2
P r ep a r a tion of (P h CH
CH TaCl (6.71 g, 13 mmol) and Me
was condensed CH Cl (100 mL) at -78 °C. The reaction
2
)
3
Ta F
2
(1). To a mixture of (C
6 5
H -
2
)
3
2
3
SnF (4.68 g, 26 mmol)
2
filtered off and the residue crystallized at -70 °C, to yield
2
2
1
mixture was warmed to room temperature and stirred for an
additional 8 h. All volatiles were removed in vacuo and the
residue sublimed at 80 °C (0.05 Torr) to afford yellow crystals.
yellow crystals of 5. Mp: 68 °C. Yield: 4.9 g (65%). H NMR
1
3
(CDCl
(CDCl
(s, SiMe
3
): 0.45 (s, 18H, CH
): 4.2 (s, CH
); 146.3 (s, CH). 29Si NMR (CDCl
). IR: v 1407 m, 1254 s, 1157 w, 1052 w, 926 m, 899
3
); 4.65 (s, 1H, CH). C NMR
3
3
3
): 5.98
1
Yield: 5.23 g (83%). Mp: 92 °C. H NMR (C
6
D
6
): 2.57 (t, 6H,
3
1
3
J (FH) ) 7.1 Hz, CH
2
); 6.95-7.1 (mult, 15H, arom H). C NMR
): 74.52 (tripl, J (FC) ) 7.1 Hz, CH
10.22 (hept, J (HF) ) 7.1 Hz). IR: v 1950 w, 1875 w, 1804 w,
740 w, 1596 m, 1573 w, 1488 s, 1450 s, 1408 m, 1264 w, 1201
s, 853 vs, 836 vs, 780 s, 751 m, 696 s, 652 s, 606 m, 579 w, 522
1
9
+
(C
6
D
6
2
). F NMR (C
6
D
6
):
w, 456 m, 382 m, 349 s, 282 w. EI MS (70 eV): m/e (%) [M
-
+
+
1
1
Me], 467 (50), [M - TMS-Cl], 359 (100), [M - CH(SiMe
323 (25). Anal. Calcd for C Si Ta: C, 17.44; H, 3.97; Cl,
29.41. Found: C, 17.8; H, 4.1; Cl, 29.1.
P r ep a r a tion of (Me Si) CHTa Br
preparation is analogous to that of 5, using TaBr
mmol) and [(Me Si) CH] Zn (0.8 g, 2.1 mmol), orange crystals.
Mp: 79 °C. Yield: 0.81 g (30%). H NMR (CDCl
18H, CH ): 2.52 (s, SiMe
), 4.45 (s, 1H, CH). 29Si NMR (CDCl
3 2
) ],
7
H
19Cl
4
2
m, 1181 w, 1156 w, 1088 m, 1181 w, 1156 w, 1087 m, 1030 m,
9
72 m, 906 m, 811 w, 796 m, 753 s, 727 m, 695 s, 622 m, 596
3
2
4
(6). The method of
(3.0 g, 5
+
s, 463 s, 343 s. EI MS (70 eV): m/e (%) [M - PhCH
2
], 401
5
(
100). Anal. Calcd for C21
Found: C, 50.9; H, 3.9; F, 7.4.
P r ep a r a tion of (p-MeC
preparation is analogous to that of 1, using (p-MeC
TaCl (1.12 g, 1.97 mmol) and Me SnF (0.8 g, 4.34 mmol). The
H
21
F
2
Ta: C, 51.25; H, 4.27; F, 7.72.
3
2
2
1
3
): 0.52 (s,
).
6
H
4
CH
2
)
3
Ta F
2
(2). The method of
CH
3
3
3
H
4
2
)
3
-
IR: v 1405 m, 1264 m, 1254 s, 1251 s, 1098 w, 1024 s, 927 m,
888 s, 852 vs, 832 vs, 778 s, 751 m, 692 m, 674 s, 646 s, 632
m, 603 m, 438 w, 332 w, 261 s, 236 s, 228 s. EI MS (70 eV):
6
2
3
resulting crude product 2 was recrystallized from pentane (10
mL) at -26 °C. Yield: 0.76 g (72%), yellow crystals. Mp: 124
+
+
+
m/e (%) [M - Me], 645 (5), [M - Br], 579 (15), [M - Me-
Br], 565 (5), [M - SiMe -Br] 491 (40), [SiMe3 ], 73 (100).
1
+
+
°
7
C. H NMR (C
6
D
6
): 2.11 (s, 9H, CH
3
); 2.68 (t, 6H, J (FH) )
3
1
3
Anal. Calcd for C H Br Si Ta: C, 12.87; H, 2.92. Found: C,
.1 Hz, CH
): 20.83 (s, CH
NMR (C ): 107.19 (hept, J (HF) ) 7.1 Hz). IR: v 1897 w,
645 w, 1612 w, 1504 s, 1465 s, 1307 w, 1216 m, 1199 m, 1128
s, 1113 s, 1022 m, 1007 m, 891 w, 812 s, 736 s, 712 m, 668 w,
42 w, 593 s, 574 s, 487 s, 466 s, 308 s. EI MS (70 eV): m/e
2
); 6.94-7.15 (mult, 12H, arom H). C NMR
7
19
4
2
1
9
13.3; H, 3.1.
P r ep a r a tion of (Me
(C
6
D
6
3
); 68.92 (tripl, J (FC) ) 6.8 Hz, CH
2
).
F
D
6
3
2 4
Si) CHTa F
(8). The method of
Si) CHTaCl
Cl (20 mL).
The residue was sublimed at 90 °C (0.05 Torr), yielding
colorless crystals of 8. Mp: 96 °C. Yield: 2.1 g (52%). H NMR
6
1
preparation is analogous to that of 1, using (Me
(2.4 g, 5 mmol), Me SnF (3.6 g, 20 mmol), and CH
3
2
4
3
2
2
6
(
(
+
+
1
%) [M - p-Tol], 429 (30), [M - p-Tol - 1,4-(CH
20), [p-Tol ], 105 (100). Anal. Calcd for C24
3
)
2
C
6
H
4
], 323
+
(CDCl ): 0.28 (s, 18H, CH ); 3.09 (s, 1H, CH). 13C NMR
H
27
F
2
Ta: C, 53.96;
3
3
(CDCl
(
3
): 2.5 (s, CH
3
); 110.7 (s, CH). 19F NMR (CDCl
3
): 81.5
H, 5.05; F, 7.11. Found: C, 53.6; H, 5.2; F, 6.8.
P r ep a r a tion of (Me SiCH Ta F (3). The method of
preparation is analogous to that of 1, using (Me SiCH TaCl
SnF (5.0 g, 27 mmol). Yield: 2.6 g
49%) after distillation, pale yellow oil. Bp: 68-70 °C (0.02
br). 29Si NMR (CDCl
): 8.10 (s, SiMe
)
3
2
3
3
). IR: v 1409 m, 1305 s,
3
2
1
254 s, 955 m, 920 s, 864 s, 839 vs, 784 m, 757 s, 723 m, 704
3
2
)
3
2
m, 688 m, 643 vs, 625 s, 579 w, 516 s, 504 s, 394 w, 302 w,
(5.6 g, 11 mmol) and Me
3
+
+
2
70 w. EI MS (70 eV): m/e (%) [M - Me], 401 (45), [M
-
(
+
1
TMS-F], 309 (100), [SiMe3 ], 73 (35). Anal. Calcd for C H F4-
Torr). H NMR (CDCl
)
)
3
): 0.12 (s, 27H, CH
). C NMR (CDCl ): 1.66 (s, CH
). 1 F NMR (CDCl
): 115.70 (hept, J (HF) ) 7.5
3
); 1.18 (t, 6H, J (FH)
7
19
1
3
2
Si Ta: C, 20.19; H, 4.60. Found: C, 19.9; H, 4.7.
Cr ysta l Str u ctu r e Solu tion a n d Refin em en t for 2, 4,
7.5 Hz, CH
7.6 Hz, CH
2
3
3
); 76.02 (t, J (FC)
9
2
3
5
, 7, a n d 8 (Ta ble 1). Data for structures 2, 4, 5, and 8 were
Hz). IR: v 2955 m, 2898 w, 1442 w, 1406 w, 1316 w, 1260 m,
collected on a STOE AED2 four-circle diffractometer with Mo
KR radiation. In the case of compound 7 data were collected
on a Stoe-Siemens-Huber four-circle diffractometer with
1
6
CH
249 s, 1118 w, 1009 w, 953 m, 913 m, 848 s, 834 s, 749 m,
+
97 m, 689 m, 601 m, 510 w. EI MS (70 eV): m/e (%) [M
-
+
3
], 465 (10), [M - CH
2
SiMe
3
], 393 (100). Anal. Calcd for
Siemens CCD area detector by use of æ and ω scans. A
12 33 2 3
C H F Si Ta: C, 30.0; H, 6.9; F, 7.9. Found: C, 29.4; H, 5.9;
semiempirical absorption correction was applied. All structures
F, 7.5.
P r ep a r a tion of (Me
ture of (Me SiCH )TaCl
9
were solved by direct methods (SHELXS-96) and refined
3
Sn Cl‚Me
(5.0 g, 12.2 mmol) and Me
Cl (50 mL). After 12 h of
stirring at room temperature all volatiles were removed in
3
Sn F ‚Ta F
5
)
n
(4). To a mix-
2
10
against F using SHELXL-97. All non-hydrogen atoms were
refined anisotropically. For the hydrogen atoms a riding model
was employed.
3
2
4
3
SnF (12.0
g, 65.6 mmol) was condensed CH
2
2
Ack n ow led gm en t. This work has been financially
supported by the Deutsche Forschungsgemeinschaft.
(
7) (a) Schrock, R. R. J . Organomet. Chem. 1976, 122, 209. (b)
Piersol, C. J .; Profilet, R. D.; Fanwick, P. E.; Rothwell, I. P. Polyhedron
993, 12, 1779. (c) Moorhouse, S.; Wilkinson, G. J . Chem. Soc., Dalton
Trans. 1974, 2187. (d) J ohnson, W. K. J . Org. Chem. 1960, 25, 2253.
e) Levchuk, L. E.; Sams, J . R.; Aubke, F. Inorg. Chem. 1972, 11, 43.
8) Elemental analyses of compound 3 cannot be improved due to
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, non-hydrogen fractional coordinates and U values, bond
lengths and angles, anisotropic displacement parameters, and
hydrogen atom coordinates and U values of 2, 4, 5, 7, and 8.
This material is available free of charge via the Internet at
http://pubs.acs.org.
1
(
(
impurities in the crude product which we were not able to remove by
distillation.
(
(
9) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467.
10) Sheldrick, G. M. SHELXL, Program for Crystal Structure
Refinement; University of G o¨ ttingen: G o¨ ttingen, Germany, 1997.
OM980768G