Synthesis and reactivity of cyclopentadienyl and indenyl ligands bearing ω-fluorinated pendant groups. Crystal structure of (ortho-F-C6H4)-CPh2-C5H 4SiMe3

Article abstract of DOI:10.1515/znb-2002-1104

A series of cyclopentadienes and indenes with ω-fluorinated pendant groups have been synthesised and their reactivity towards metallating agents n-BuLi, NaH, TIOEt, Me₃SiCl, Me₃SnCl, TiHal₄, ZrX₄ (X = Cl, NMe₂) has been investigated. The crystal structure of 1-trimethylsilyl-3-(diphenyl-ortho-fluorophenyl-methyl)-cyclopentadiene (3) was determined.

Full text of DOI:10.1515/znb-2002-1104

Synthesis and Reactivity of Cyclopentadienyl and Indenyl Ligands
Bearing -Fluorinated Pendant Groups.
Crystal Structure of (ortho-F-C6H4)-CPh2-C5H4SiMe3
A. Khvorosta , D. Lemenovskiia, N. Ustynyukb, K. Rufanovb , and J. Kipkec
a
Department of Chemistry, Lomonosov Moscow State University,
Vorob’evy Gory, RUS-119899, Moscow, Russian Federation
b A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Science,
Vavilov street 28, RUS-117813, Moscow, Russian Federation
c
Fachbereich Chemie, Philipps-Universita¨t Marburg,
Hans-Meerwein Strasse, D-35043, Marburg (Lahn), Germany
Present address: AK Sundermeyer, Fachbereich Chemie, Philipps-Universita¨t Marburg,
Hans-Meerwein Strasse, D-35043, Marburg (Lahn), Germany
Present address: TU Berlin, Institut fu¨r Chemie,
Sekretariat C2, Strasse des 17. Juni 135, D-10623 Berlin, Germany
Reprint requests to A. Khvorost. Fax: (049)06421-2828917.
E-mail: san@chemie.uni-marburg.de
Z. Naturforsch. 57 b, 1207–1214 (2002); received November 29, 2001
Half-Sandwich Complex, Intra-molecular Stabilisation, Transmetallation
A series of cyclopentadienes and indenes with -fluorinated pendant groups have been
synthesised and their reactivity towards metallating agents n-BuLi, NaH, TlOEt, Me3SiCl,
Me3SnCl, TiHal4, ZrX4 (X = Cl, NMe2) has been investigated. The crystal structure of 1-tri-
methylsilyl-3-(diphenyl-ortho-fluorophenyl-methyl)-cyclopentadiene (3) was determined.
1. Introduction
Marks and co-workers [8] have stabilised the zir-
conocene system by interaction with tris(pentafluo-
rophenyl)borane (A). It has been proved that coor-
dination of fluorine to a metal centre favours the
stabilisation, but this interaction is rather weak and
does not neutralise the electrophilic properties of
the cationic species. Erker [9] and Piers and co-
workers [10] have modified this system by creating
Zr-F intramolecular interactions on the basis of met-
allocene zwitterionic species (B).
Half-sandwich complexes of early transition met-
als with bulky substituents are interesting as poten-
tial catalysts for olefin polymerisation [1 - 5]. The
efficiency of such catalysts depends on the stability
of the cationic complexes formed in the process of
catalysts activation [6]. Modifying the ligand en-
vironment of the metal centre one can control the
stability of the complexes and have an influence
on the physic-chemical properties of the resulting
polymers.
One of the possibilities to achieve stabilisation
of cationic species consists of the modification of
the Cp-ligand with pendant substituents, which can
provide protection of the metal centre by weak coor-
dination. Such a substituent should not have strong
s- or p-donor character in order not to depress the
Lewis-acidity and the catalytic properties of the
transition metal centre. Groups bearing -fluorine
atoms seem to be likely candidates for exerting this
stabilising effect.
Scheme 1.
Our aim was the creation and further investiga-
tion of certain systems with intra-molecular F
M
c
¨
¨
0932–0776/02/1100–1207 $ 06.00
2002 Verlag der Zeitschrift fur Naturforschung, Tubingen www.znaturforsch.com
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A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
Scheme 2.
Scheme 3.
Scheme 4.
interaction, where the fluorine atom is in the tail-
position of the organic ligand.
Results and Discussion
ortho-Fluorophenyl-diphenylmethyl-cyclopenta-
diene (1)
For the synthesis of this ligand we synthesised
the corresponding tritylchloride (Scheme 2) by re-
action of ortho -fluoromethylbenzoate with 2 equiv-
alents of phenylmagnesium bromide followed by
SN1 OH/Cl exchange with an excess of acetyl chlo-
ride [11].
Subsequent substitution of halogen by cyclopen-
tadienyl has been achieved by the previously devel-
oped method [6, 7] using nickelocene as a Cp-source
(Scheme 3).
Scheme 5.
According to TLC a mixture of at least 3-4 com-
pounds was obtained in the reaction of tritylchloride
with CpTl excluding the target product. We specu-
late that the possible mechanism of this reaction is
that of Scheme 6.
This mechanism would explain the red colour
of the reaction mixture, which is characteristic for
systems containing Cp- and trityl- radical species.
Attempts to deprotonate 1 with several bases such
as n-BuLi or NaH in ethereal solvents (Et2O, THF,
The process affords good yields and occurs prob-
ably via a radical mechanism including the steps of
Scheme 4.
The product is a white crystalline solid consist- DME) have failed, while the parent Ph3CCp is
ing of two isomers 1a and 1b in a ratio 3.5 1. smoothly deprotonated under these conditions [12].
Alternatively this ligand can be synthesised by However 1 reacts with n-BuLi in pentane to give the
metathesis reaction of diphenyl-ortho-fluorophe- lithium salt of the ligand. After 30 h the Li-salt 2 was
nyl-methylchloride with CpSnMe3, while direct quenched by addition of Me3SiCl converting it into
substitutions with CpNa, CpK or even CpTl in THF the trimethylsilyl derivative 3, which was obtained
were found to be unsuccessful (Scheme 5).
as a white crystalline powder. This compound exists
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A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
1209
Scheme 6.
Scheme 7.
Scheme 9.
Scheme 8.
half-sandwich complexes 5 and 6 with good yields
(Scheme 9).
in the form of one isomer (3-Me3Si-Cp). Obviously
the bulky Me3Si-group rules out the formation of
the 2-substituted isomer (Scheme 7).
The products are yellow micro-crystalline pow-
ders, slowly decomposing in the presence of mois-
ture, but stable in an inert atmosphere. According to
the 19F NMR chemical shifts data there is no interac-
tion between the metal atoms and the fluorine atom
in 5 and 6. The possible reason for this observation
lies in the bulkiness of the ligand system.
Direct metallation of 1 was achieved in reactions
with Me3SnNMe2 and with TlOEt. The grey precip-
itate of the Tl-salt 4 is formed quantitatively, while
the trimethyltin derivative is formed only after heat-
ing the toluene solution of 1 with Me3SnNMe2 un-
der reflux for 12 h. However, even in this case the
reaction is incomplete and the yield is very poor.
Further attempts of a direct metallation of 1 with zir-
conium amides (Zr(NR2)4, R = Me, Et) also failed
(Scheme 8).
Transmetallation of 3 with TiX4 (X = Cl, Br)
was not successful. Immediate colour change from
yellow to brown-red occurs just after the addition
of 3 to a solution of the titanium halide. The only
product isolated in these reactions was TiX3 (X =
Cl, Br). Reduction occurs even at –100 C. A pos-
sible reason for this may be the pre-coordination of
TiX4 forming an adduct with a Ti-F bond, in which
the position of the Me3Si-group at the Cp-ring is
unfavourable for further substitution, whereas the
double bond is available and, therefore, a fast halo-
gen transfer from Ti can readily occur.
1-(ortho-Fluorobenzyl)-indene
1-(ortho-Fluorobenzyl)-indene 7 was obtained
by interaction of indenyl-lithium with ortho-fluoro-
benzylchloride in diethylether (Scheme 10).
The product was purified by distillation in a vac-
uum and obtained as an intensively green oily liquid,
slowly darkening on air. It consists of a mixture of
two isomers 7a and 7b in the ratio 3:10 according to
the 19F-NMR data. The possible reason for this dis-
tribution may be a H F hydrogen bond formation
in 7b, which makes this isomer more stable.
In order to obtain a soft transmetallation agent we
synthesised the stannyl-derivative 8 by metallation
of 7 with n-BuLi and subsequent quenching of the
Li-salt with trimethyltin chloride (Scheme 11).
Compound 8, a dark-red oil, sensitive to air mois-
By contrast the Tl-salt 4 smoothly reacts with
both TiCl4 and ZrCl4 providing the corresponding ture, exists as only one isomer.
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1210
A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
Scheme 10.
Scheme 11.
Scheme 12.
The analogous Me3Si-derivative 9 was obtained
The trimethylsilyl derivative 9 does not react with
in good yield (81%) by interaction of the lithium salt TiCl4 even in boiling toluene. The NMR spectrum
of 1-trimethysilylindene with ortho-fluorobenzyl- of the product was identical with that of the starting
chloride (Scheme 12). The product 9 consists of a material 9.
Interaction of two equivalents of 8 with 1 eq. of
ZrCl4 leads to a mixture of two products – slightly
mixture of three isomers 9a-c in the ratio of 3.5:5:1.
The formation of the isomer 9c was unexpected.
By reaction of 8 with TiCl4 in petroleum ether at yellow crystals and a red oil, which according to
room temperature we obtained several products, as NMR data are half-sandwich and sandwich species.
suggested by the mass-spectrum (Scheme 13). The Since an analogous product with a para-fluoro-
mechanism of this reaction was not investigated. An benzyl substituent was easily obtained [14], we con-
exchange of methyl groups with chlorine atoms of clude that after addition of the first equivalent of the
one of the indenyl-groups with chlorine atoms be- ligand to zirconium a coordination of the fluorine to
tween organotin and titanium species are proposed
in this case.
the metal atom takes place and hinders the addition
of the second equivalent.
Changing the reaction conditions to the inverted
order of reagents mixing [13] gave the same result
(even under very mild reaction conditions: –100 C,
petroleum ether).
Structure Determination
The molecular structure of 3 has been deter-
mined by X-ray diffraction. The trimethylsilyl moi-
ety occupies exclusively the allilyc -bonded po-
sition in the cyclopentadiene ring. There is no in-
teraction between the trimethylsilyl and the fluoro
substituents. The C(4) atom is tetrahedral with an-
gles Si(1)-C(4)-C(3) = 109.2(1) , Si(1)-C(4)-C(5) =
110.0(1) , C(5)-C(4)-C(3) = 102.9(2) . The bond
length Si(1)-C(4) is 190.7(2) pm, nearly equal to
the bond length Si-CCp in its unsubstituted analogue
Scheme 13.
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A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
1211
Table 1. Selected bond lengths (pm) and bond angles ( )
for 3.
Aldrich and degassed several times before use. Zirco-
nium amides were received in-house. Nickelocene was
obtained according to [15]. Cyclopentadienyltrimethyltin
was distilled twice under argon prior to use. The Grig-
Si(1)-C(7)
Si(1)-C(8)
Si(1)-C(9)
Si(1)-C(4)
F(1)-C(11)
C(1)-C(10)
C(1)-C(20)
C(1)-C(30)
185.9(2) C(10)-C(11)
186.3(3) C(2)-C(3)
186.2(3) C(1)-C(2)
190.7(2) C(3)-C(4)
133.7(3) C(2)-C(6)
154.4(3) C(5)-C(6)
155.0(3) C(4)-C(5)
154.6(3)
135.6(3)
135.0(3)
153.1(3)
148.7(3)
145.9(3)
134.0(3)
148.2(3)
n
nard reagent and BuLi hexane solutions were prepared
by routine procedures. CpTl was prepared by interaction
of a mixture of thallium formiate and thallium malonate
with cyclopentadiene in aqueous KOH solution.
The NMR spectra were recorded with Bruker AC 300
(1H, 19F: 300 MHz, 13C: 75 MHz) and Varian VXR-400
(1H, 19F: 400 MHz, 13C: 100 MHz) spectrometers. As
internal standard for 19F spectroscopy the chemical shift
of CFCl3 was used. The elemental analysis was performed
on a Carlo-Erba analyser. Mass-spectra were recorded on
a Varian CH-7a MAT spectrometer (EI-MS, E = 70 eV).
Melting points were determined in sealed capillaries and
are uncorrected.
C(7)-Si(1)-C(8) 112.1(1) C(2)-C(1)-C(20) 106.3(2)
C(9)-Si(1)-C(8) 108.0(1) C(2)-C(1)-C(10) 109.69(2)
C(7)-Si(1)-C(9) 110.7(1) C(5)-C(4)-C(3) 102.9(2)
C(4)-Si(1)-C(9) 109.3(1) C(3)-C(4)-Si(1) 109.2(1)
C(7)-Si(1)-C(4) 108.3(1) C(6)-C(2)-C(1) 123.3(2)
C(8)-Si(1)-C(4) 108.4(1) C(10)-C(1)-C(20) 110.5(2)
F(1)-C(11)-C(10) 119.3(2) C(5)-C(4)-Si(1) 110.0(1)
C(1)-C(10)-C(11) 120.2(2) C(2)-C(3)-C(4) 109.9(2)
C(3)-C(2)-C(1) 128.8(2) C(6)-C(5)-C(4) 109.5(2)
C(5)-C(6)-C(2) 109.7(2) C(30)-C(1)-C(20) 110.1(2)
C(2)-C(1)-C(30) 112.4(2) C(3)-C(2)-C(6) 107.8(2)
Diphenyl-ortho-fluorophenyl-methanol
An ethereal solution of phenylmagnesium bromide
(0.245 mol) was added to a solution of methyl-ortho-
fluoro-benzoate (19.1 g, 0.124 mol), the mixture refluxed
for 1h, and then poured on ice cold water. After extrac-
tion with Et2O (at pH 5.5) and washing of the ethereal
phase with water the solution was dried over MgSO4,
solvent was evaporated and the product obtained washed
with petroleum ether and dried. White powder. Yield 63%
(21.75 g).
M. p. 123 C. – 1H NMR (400 MHz, d6-acetone):
=
5.23 (d, 4JH = 33.44 Hz, 1H, OH), 7.03 - 7.16, 7.24 -
F
7.39 (m, m, 14H, CHAr). – 13C NMR (100 MHz, d6-acet-
one): = 81.32 (COH), 116.79 (d, 2JC F = 22.2 Hz, C-3a),
124.46 (d, 4JC F =3.7 Hz, C-5a), 127.79 (C-4), 128.33 (C-
3), 128.44 (C-2), 130.25 (d, 3JC F = 3.6 Hz, C-6a), 130.40
3
2
(d, JC = 8.4 Hz, C-4a), 135.58 (d, JC = 11.6 Hz,
F
F
C-1a), 147.19 (C-1), 161.14 (d, 1JC F = 245.9 Hz, C-1a).
–
19F NMR (400 MHz, d6-acetone): = –108.52 (CF).
– MS (EI, 70 eV): m/z (%) = 278 (23) [M+], 261 (67)
[M+-OH], 201 (47) [M+-Ph]. – C19H15FO (278.3): calcd.
C 81.99, H 5.43; found C 81.26, H 5.94.
Fig. 1. Crystal structure of 1-[(C6H5)2(ortho-F-C6H4)]-
C(C5H3-3-SiMe3) (3).
(trityltrimethylsilylcyclopentadiene) [6]. The dou-
ble bonds of the cyclopentadiene ring in 3 differ in
their length, (C(2)-C(3) = 135,0(3) pm, C(5)-C(6) =
134,0(3) pm, indicating double bonds similar to the
unsubstituted analogue (136.0(2) and 133.4(3) pm).
Diphenyl-ortho-fluorophenyl-methylchloride
A benzene solution of diphenyl-ortho-fluorophenyl-
methanol (11.1 g, 40 mmol) was added to acetyl chloride
(2.9 ml, 40 mmol) with vigorous stirring. After 10 min
the rest (4.3 ml, 60 mmol) was added. After 40 min. of
reflux benzene was evaporated to 30 ml and the prod-
uct crystallised from benzene-petroleum ether at –20 C.
Experimental Section
All experiments were carried out in an argon atmo- Then precipitate was separated by filtration and dried in
sphere. All solvents were purified by standard methods a vacuum. White crystalline powder. Yield 62% (7.3 g).
and were freshly distilled prior to use. Me3SiCl and TiCl4
M. p. 102 C. – 1H NMR (300 MHz, d6-acetone):
=
were distilled over Al2O3. ZrCl4 was purchased from 6.78 - 7.51 (m, 14H, CHAr). – 13C (75 MHz, d6-acetone):
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A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
=80.33 (CCl), 116.81(d, 1JC F =22.5 Hz, C-3a), 117.50 116.6 (d, JC = 22.9 Hz, C-3a), 126.7 - 128.3 (CAr),
2
F
3
2
(d, 2JC = 22.5 Hz, C-1a), 127.82 (C-2), 128.41 (C-3), 130.54 (d, JC = 20.2 Hz, C-4a), 131.03 (d, JC
=
F
F
F
4
129.62 (C-4), 131.91 (d, JC = 8.7 Hz, C-5a), 133.31 4.7 Hz, C-1a), 134.63 (C-11), 145.32 (C-9), 149.26 (C-
F
(d, JC = 9.8 Hz, C-4a), 135.58 (d, JC = 11.3 Hz, 1), 162.93 (C-2). – 19F NMR (400 MHz, CDCl3):
=
3
3
F
F
C-6a), 144.54 (C-1), 162.32 (d, 1JC = 248.6, C-2a). – –99.03. – MS (EI, 70 eV): m/z (%) = 398 (48) [M+], 325
F
19F NMR (300 MHz, d6-acetone): = –98.68 (CF). – MS (29) [M+-SiMe3], 303 (25) [M+-FC6F4], 261 (97) [M+-
(EI, 70 eV): m/z (%) = 261 (82) [M+-Cl], 183 (32) [M+- CpSiMe3]. – C27H27FSi (398.6): calcd. C 81.36, H 6.83;
Cl-Ph-H]. – C19H14ClF (296.8): calcd. C 76.90, H 4.75; found C 80.97, H 7.04.
found C 76.53, H 5.16.
Diphenyl-ortho-fluorophenyl-methyl-cyclopenta-
dienyl-thallium (4)
Diphenyl-ortho-fluorophenyl-methyl-cyclopentadiene (1)
Nickelocene (2.3 g, 12.5 mmol) dissolved in THF was
added to the benzene solution (30 ml) of diphenyl-ortho-
fluorophenyl-methylchloride (7.3 g, 25 mmol). A brown
precipitate was observed. After 25 min the mixture was
filtered and the solvent evaporated. The product was pu-
rified through recrystallisation from heptane and was ob-
tained as a white crystalline solid. Yield 82% (6.69 g).
M. p. 185 C. – 1H NMR (300 MHz, C6D6): = 2.82,
2.85 (q, q', J = 1.5 Hz, 2H, H-7, H-7', the ratio q/q' is
3.5/1), 6.10-6.20, 6.23-6.29, 6.30-6.35 (m, m, m, 3H, -
CCpH=), 6.60-6.94, 6.98-7.15, 7.28-7.44 (m, m, m, 14H,
CArH). – 13C (75 MHz, C6D6): = 40.90 (C-7), 44.33 (C-
Thallium ethylate (0.5 ml, 6.87 mmol) was added to
the saturated solution of 1 (2.24 g, 6.87 mmol) in toluene.
After 30 h stirring at room temperature the solution was
filtered and the grey precipitate obtained was washed with
toluene (2 10 ml) and dried in a vacuum. Yield 100%.
MS (EI, 70 eV): m/z (%) = 530 (10) [M++H], 325 (68)
[M+-Tl].
Diphenyl-ortho-fluorophenyl-methyl-cyclopentadienyl-
titanium trichloride (5)
TiCl4 (0.33 ml, 3 mmol) was added to the suspension
of 4 (3 mmol) in toluene. The reaction mixture was left
overnight. Then the solution was filtered and the solvent
evaporated. The product was recrystallised from toluene-
pentane. Greenish yellow powder, yield 84% (1.20 g).
7'), 59.23 (C-12), 116.43 (C-3a), 116.84 (C-6a), 123.93
4
(C-3), 127.93 (C-4), 132.31 (C-11), 129.92 (d, JC
=
F
8.4 Hz, C-5a), 133.15 (C-2), 135.50 (d, 3JC = 11.2 Hz,
F
C-4a), 137.31 (C-10), 144.59 (C-9), 145.90 (C-1), 146.00
2
(d, JC = 37.7 Hz, C-1a), 150.88 (C-11'), 161.55 (d,
F
1H NMR (400 MHz, d8-toluene): = 6.52, (dt, J1 =
1.6 Hz, J2 = 78.2 Hz, 4H, CHCp), 6.72 - 7.43 (m, 14H,
CHAr). – 13C (100 MHz, d8-toluene): = 45.83 (C-12),
1JC = 249.8 Hz, C-2a). – 19F NMR (300 MHz, C6D6):
F
= –102.56 (CF, 1a), –100.88 (CF, 1b) (ratio 1a/1b is
3.5/1). – MS (EI, 70 eV): m/z (%) = 326 (89) [M+], 261
(54) [M+-Cp], 184 (31) [M+-Cp-Ph]. – C24H19F (326.4):
calcd. C 88.31, H 5.87; found C 88.12, H 6.23.
109.16 (CCpH), 117.18 (d, 2JC F = 20.5 Hz, C-3a), 123.52
4
(d, JC = 3.8 Hz, C-5a), 127.53 (C-4), 128.63 (C-3),
F
3
3
131.05 (d, JC = 8.2 Hz, C-6a), 130.53 (d, JC
=
F
F
8.3 Hz, C-4a), 136.25 (C-2), 136.73 (d, 2JC = 11.6 Hz,
F
1-Trimethylsilyl-3-(diphenyl-ortho-
fluorophenyl-methyl)-cyclopentadiene (3)
C-1a), 147.19 (C-1), 160.32 (d, 1JC F = 248.4 Hz, C-2a).
–
19F NMR (400 MHz, d8-toluene): = –100.33 (CF). –
MS (EI, 70 eV): m/z (%) = 478 (36) [M+-H], 443 (26)
[M+-HCl], 406 (63) [M+-2Cl-H]. – C24H18Cl3FTi (479.7):
calcd. C 60.10, H 3.78; found C 59.88, H 3.98.
A nBuLi solution in hexane (15 mmol) was dropped to
a suspension of 1 (3.26 g, 10 mmol) in petroleum ether
at room temperature. The mixture was stirred for 30 h,
then the solution was filtered, the precipitate washed with
pentane (2 25 ml) and dried. The lithium salt obtained
was used without further purification and analysis. It was
suspended in toluene and trimethylsilylchloride (2.5 ml,
15 mmol) was added at room temperature. After 12 h
the mixture was filtered, the solvent evaporated and the
residue was dried in a vacuum. The product (orange oil)
was crystallised from pentane. Yield 63% (2.50 g).
Diphenyl-ortho-fluorophenyl-methyl-cyclopentadienyl-
zirconium trichloride (6)
The product was obtained in a same way as 5. Rose
powder, yield 76%.
1H NMR (300 MHz, d8-toluene): = 6.11, (dt, J1 =
1.8 Hz, J2 = 83.6 Hz, 4H, CHCp), 6.69 - 7.38 (m, 14H,
M. p. 89 C. – 1H NMR (400 MHz, CDCl3): = –0.1 (s, CHAr). – 13C (75 MHz, d8-toluene): = 43.64 (C-12),
9H, SiMe3), 3.14 (t, J = 1.4 Hz, 1H, H-7), 6.45, 6.30-6.21 115.16 (CCpH), 127.91 (C-4), 128.23 (C-3), 137.43 (C-2),
(br. t, br. dt, 1H, 2H, H-8, H-10, H-11), 7.42-7.39, 7.16- 160.32 (d, 1JC F = 259.6 Hz, C-2a) – 19F NMR (400 MHz,
7.00, 6.92-6.68 (m, 14H, CHAr). – 13C (75 MHz, C6D6): d8-toluene): = –100.06 (CF). – MS (EI, 70 eV): m/z
= –1.71 (SiMe3), 50.29 (C-7), 59.6 (C-12), 116.2 (C-8), (%) = 487 (87) [M+-Cl], 468 (34) [M+-Cl-F], 452 (43)
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A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
1213
[M+-2Cl], 433 (48) [M+-2Cl-C6H4F]. – C24H18Cl3FZr
(523.0): calcd. C 55.12, H 3.47; found C 54.67, H 4.05.
Table 2. Crystallographic data for 1-[(C6H5)2 (ortho-F-
C6H4)]C(C5H3-3-SiMe3) (3).
Chemical formula
Crystal system
Mol. wt.
C27H27FSi
monoclinic
398.58
1-(ortho-Fluorobenzyl)-indene (7)
n
A hexane solution of BuLi (35 mmol) was added to
a cooled (–35 C) ethereal solution of freshly distilled
indene (35 mmol). After coming to room temperature
( 30 min) a solution of ortho-fluorobenzylchloride was
dropped to the reaction mixture. 10 min after addition a
white precipitate was observed. The mixture was stirred
overnight. Then it was mixed with NH4Cl-saturated water
solution and extracted with Et2O (2 10 ml). The com-
bined organic fraction was washed with water and dried
over MgSO4. The solvent was evaporated and the dark
green oil distilled in a vacuum (B. p. 150 - 160 C / 1 Torr).
Green oily liquid, slowly decomposing on air, yield 77%
(5.65 g). 1H NMR (400 MHz, d8-toluene): = 2.57 (dd,
J1 = 3.6 Hz, J2 = 9.0 Hz, 2H, H-7), 3.00 (dd, J1 = 7.7 Hz,
J2 = 6.6 Hz, 2H, H-7'), 3.62 (dd, J1 = 2.0 Hz, J2 = 8.3 Hz,
2H, H-8'), 3.76 (s, 2H, H-10), 5.87 (s, 1H, H-9), 6.24, 6.59
(dd, dd, J1 = 3.8 Hz, J2 = 1.7 Hz, 1H, 1H, H-9', H-10'),
6.72 - 6.88, 6.96 - 7.25 (m, m, 16H, CHAr) (ratio 7a/7b =
3:10). – 13C (100 MHz, d8-toluene): = 27.29 (C-7),
31.29 (C-7'), 37.72 (C-10), 50.70 (C-8'), 115.28 (C-9'),
115.51 (C-10'), 119.42 (C-9), 121.40 (C-13), 123.41 (C-
14), 123.94 (C-8), 125.03 (C-5), 127.00 (C-6), 127.67 (C-
12), 127.91 (C-15), 128.14 (C-4), 131.50 (C-3), 144.61
(C-11), 147.05 (C-16), 161.73 (d, 1JC F = 247.0 Hz, C-2).
Cell dimensions
a [pm]
1584.8(1)
1225.1(2)
1149.7(1)
91.785
2231.2(4)
17.52 - 22.37
4058
b [pm]
c [pm]
[deg]
V [10 30 m3]
Scan range 2 , deg
Number of reflections
For I0 > 2 ( I0|)
Space group
Z
3542
P21/c
4
Rw
0.1732
120.30 (CF). – MS (EI, 70 eV): m/z (%) = 287 (72) [M+],
372 (87) [M+-Me], 342 (62) [M+-3Me], 223 (58) [M+-
SnMe3]. – C19H21FSn (387.1): calcd. C 58.96, H 5.47;
found C 58.24, H 6.02.
Trimethylsilyl-1-(ortho-fluorobenzyl)-indene (9)
nBuLi in hexane (10 mmol) was added to the solu-
tion of trimethylsilylindene (1.9 g, 10 mmol) in Et2O at
–35 C. After coming to room temperature ( 30 min)
ortho-fluorobenzyl-chloride (1.2 g, 10 mmol) was added
via a syringe. Formation of a white precipitate of LiCl
was observed directly after adding Me3SiCl. After 12 h
stirring the mixture was poured into water, extracted with
Et2O (2 10 ml) and the combined organic phase dried
over MgSO4. Then the solvent was evaporated and the
residue was distilled in a vacuum. Slightly green oily liq-
uid, slowly darkening on air. Yield 81% (2.40 g). B. p. 170
–
19F NMR (400 MHz, d8-toluene): = –118.47 (CF). –
MS (EI, 70 eV): m/z (%) = 224 (17) [M+], 115 (30) [Ind].
– C16H13F (224.3): calcd. C 85.69, H 5.84; found C 85.34,
H 5.95.
1-(ortho-Fluorobenzyl)-3-trimethylstannyl-indene (8)
A hexane solution of BuLi (40 mmol) was added to - 175 C/1 Torr. – 1H NMR (400 MHz, CDCl3): = 0.08
the cooled (–35 C) ethereal solution of 7 (9 g, 40 mmol). (s, 9H, SiMe3, H-17'), 0.11 (s, 9H, SiMe3, H-17''), 0.41
After coming to room temperature ( 30 min) the sus- (s, 9H, SiMe3, H-17), 3.08 (dq, J1 = 4.8 Hz, J2 = 9.6 Hz,
pension of the salt was cooled down to 0 C and the J3 = 122.3 Hz, 2H, H-7'), 3.09 (s, 2H, H-7''), 3.56 (d, J =
ethereal solution of trimethyltinchloride (8 g, 40 mmol) 3.2 Hz, 2H, H-7), 3.91 (t, J = 6.8 Hz, H-10), 4.12 (t, J =
dropped to the mixture. After 12 h the dark red solution 20.0 Hz, 1H, H-8'), 6.74 (dd, J1 = 92.3 Hz, J2 = 2.4 Hz,
was decanted from the precipitate of LiCl, the solvent was 2H, H-9'', H-10'') 6.75 (dd, J1 = 4.4 Hz, J2 = 2.6 Hz, 1H,
evaporated and the product thoroughly dried in a vacuum H-9'), 7.03 (dd, J1 = 2.9 Hz, J2 = 1.7 Hz, 1H, H-9), 7.13 -
n
(80 C, 10 Torr). Dark red oily liquid, decomposing 7.60 (m, CHAr), ratio 9a/9b/9c is 3.5/5/1. – 13C (100 MHz,
2
at contact with air and moisture. Yield 97% (15.0 g). 1H CDCl3): = –2.56 (SiMe3, C-17''), –2.44 (SiMe3, C-17),
NMR (400 MHz, C6D6): = –0.21 (s, 9H, SnMe3), 3.69 –1.15 (SiMe3, C-17'), 27.96 (C-7'), 29.69 (C-7''), 31.18
(s, 1H, H-10), 3.98 (s, 2H, H-7), 6.25 (s, 1H, H-9), 6.75 - (C-7), 44.73 (C-8'), 50.40 (C-8''), 51.64 (C-10), 114 - 159
7.52 (m, 8H, CHAr). – 13C (100 MHz, C6D6): = –9.58 (CAr and CInd), 161.08 (d, 1JC F = 247.4 Hz, C-2), 161.17
(SnMe3), 27.25 (d, JC = 3.2 Hz, C-7), 42.87 (C-10), (d, 1JC F = 248.6 Hz, C-2''), 161.35 (d, 1JC F = 245.6 Hz,
3
F
115.44 (d, JC = 20 Hz, C-6), 119.58 (C-15), 121.68 CAr-2'). – 19F NMR (400 MHz, CDCl3): = –120.07
3
F
(C-13), 121.74 (C-12), 123.75 (C-14), 124.15 (d, 4JC
=
(CF, 9a), –120.37 (CF, 9b), –121.39 (CF, 9c). – MS (EI,
F
3.7 Hz, C-5), 131.73 (d, JC = 56.2 Hz, C-3), 135.78 70 eV): m/z (%) = 296 (18) [M+], 233 (24) [M+-SiMe3].
2
F
(C-8), 142.08 (C-11), 147.03 (C-16), 161.59 (d, 1JC
=
– C19H21FSi (296.5): calcd. C 76.98, H 7.14; found C
F
243.5 Hz, C-2). – 19F NMR (400 MHz, C6D6): = – 76.22, H 7.63.
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1214
A. Khvorost et al. · Synthesis and Reactivity of -Fluorinated Ligands
Structure determination
Crystallographic data have been deposited with
the Cambridge Crystallographic Data Centre, CCDC-
166431. Copies of the data can be obtained free of charge
on application to The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (Fax: int.code+(1223)336-033;
e-mail for inquiry: fileserv@ccdc.cam.ac.uk
Data collection was performed at room temper-
ature with an Enraf-Nonius CAD-4 diffractometer
using graphite monochromatic Mo-K radiation (
71.073 pm) and scans. 4058 unique reflections were
measured in the range 17.52 < 2 < 22.37 . The Rw value
was 0.0583 for 3542 observed reflections (I > 2 (I)). Ap-
proximate positions for the Si atom were obtained using
=
Acknowledgements
We thank Drs. E. V. Avtomonov (Bayer AG), A. V.
direct methods (SHELXS-97 program) and the remaining Churakov (Kurnakov-Institute of General and Inorganic
non-hydrogen atoms were located by successive differ- Chemistry, Moscow), M. V Borzov (Department of
ence Fourier syntheses. In the anisotropic refinement of Chemistry, Lomonosov State University, Moscow) and
non-hydrogen atoms the hydrogen atoms were included V. V. Kotov (Universita¨t Mu¨nster, Germany) for intellec-
as fixed contributions using a riding model.
tual support and helpful discussions.
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