Synthesis and Structural Diversity of Triaryl(phenylethyl)silanes

Article abstract of DOI:10.1055/s-0039-1690785

Starting from trichloro(phenylethyl)silane, six differently fluorinated triaryl(phenylethyl)silanes were synthesized by salt elimination reactions and their structures were determined by X-ray diffraction analysis. Tris(pentafluorophenyl)(phenylethyl)silane reveals a folded structure due to intramolecular π-stacking interactions, while those with a lower degree of fluorination show either intermolecular π-stacking or no interplay between the aryl groups. A similar folded structure was observed for (4-methylphenethyl)tris(pentafluorophenyl)silane and [2-(naphth-2-yl)ethyl]tris(pentafluorophenyl)silane, both generated from the corresponding trichlorosilanes. In contrast, the inversely fluorinated [2-(pentafluorophenyl)ethyl]triphenylsilane only revealed intermolecular π-stacking interactions. Compounds with tetrafluoropyridyl substituents behave differently; with these compounds, π-stacking is only observed between the fluorinated units. All compounds were analyzed by NMR and IR spectroscopy, elemental analyses and single-crystal X-ray diffraction, and found to have strong H/C/N/F···F and N···C contacts.

Full text of DOI:10.1055/s-0039-1690785

SYNTHESIS
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© Georg
Thieme Ver-
lag Stuttgart
· New York
2020, 52, A–J
A
M. Linnemannstöns et al.
Paper
Synthesis
Synthesis and Structural Diversity of Triaryl(phenylethyl)silanes
Marvin Linnemannstöns
Beate Neumann
Hans-Georg Stammler
Norbert W. Mitzel*
Universität Bielefeld, Fakultät für Chemie,
Lehrstuhl für Anorganische Chemie und
Strukturchemie, Universitätsstraße 25,
33615 Bielefeld, Germany
mitzel@uni-bielefeld.de
Received: 12.11.2019
Accepted: 06.12.2019
Published online: 13.01.2020
DOI: 10.1055/s-0039-1690785; Art ID: ss-2019-c0626-op
are of equal magnitude but of opposite sign.4 Later investi-
gations revealed that London dispersion has at least the
same impact on the total interaction energy as the electro-
static term.5 Intermolecular interactions involving aromatic
rings play an important role in many supramolecular recog-
nition processes;6 for example, in the intercalation of drugs
to DNA,7 in host-guest complexation,8 and in crystal engi-
neering.9 The creation of a toolbox with specific molecular
building blocks that induce a particular kind of inter- or in-
tramolecular interactions in a system would be a great ben-
efit for synthetic chemists in the development and design of
new molecules. Recently, we reported on the structural
characteristics of partially fluorinated bis-arenes in the
solid and the gas phase.10 H5C6–(CH2)2SiMe2–C6F5 contains a
–(CH2)2SiMe2– linker unit connecting a phenyl and a penta-
fluorophenyl group. The existence of two conformers was
detected by gas-phase electron diffraction (GED). The most
abundant conformer (A) is stabilized by intramolecular -
stacking, while the other one (B) is stabilized by – inter-
actions (Figure 1). This led us to the question of whether
substitution of the two methyl groups with further penta-
fluorophenyl moieties would suppress the – conformer
and exclusively lead to the structure stabilized by intramo-
lecular -stacking interactions.
Abstract Starting from trichloro(phenylethyl)silane, six differently flu-
orinated triaryl(phenylethyl)silanes were synthesized by salt elimination
reactions and their structures were determined by X-ray diffraction
analysis. Tris(pentafluorophenyl)(phenylethyl)silane reveals a folded
structure due to intramolecular -stacking interactions, while those
with a lower degree of fluorination show either intermolecular -stack-
ing or no interplay between the aryl groups. A similar folded structure
was observed for (4-methylphenethyl)tris(pentafluorophenyl)silane and
[2-(naphth-2-yl)ethyl]tris(pentafluorophenyl)silane, both generated
from the corresponding trichlorosilanes. In contrast, the inversely fluori-
nated [2-(pentafluorophenyl)ethyl]triphenylsilane only revealed inter-
molecular -stacking interactions. Compounds with tetrafluoropyridyl
substituents behave differently; with these compounds, -stacking is
only observed between the fluorinated units. All compounds were ana-
lyzed by NMR and IR spectroscopy, elemental analyses and single-crys-
tal X-ray diffraction, and found to have strong H/C/N/F···F and N···C
contacts.
Key words inter/intramolecular -stacking, solid-state structures,
London dispersion, bridged arenes, fluorinated arenes
The first report on the interactions between fluorinated
and non-fluorinated arenes was published by Patrick and
Prosser in 1960.1 They obtained colorless crystals by mixing
equimolar amounts of benzene (C6H6; mp 6 °C) and hexa-
fluorobenzene (C6F6; mp 4 °C). The melting point of this 1:1
complex was 24 °C and thus about 19 °C higher than those
of the individual components. In contrast to the her-
ringbone-like relative arrangements of the molecules in the
crystal structures of pure C6H6 and C6F6,2 the co-crystal
C6H6·C6F6 consists of columnar stacks of alternating ben-
zene and hexafluorobenzene molecules.3 First attempts to
explain this phenomenon were based on the interaction be-
tween the quadrupolar moments of C6H6 and C6F6, which
Figure 1 Structures of the – (A) and the – conformer (B) of di-
methyl(pentafluoro)(2-phenylethyl)silane determined by GED10
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J
Georg Thieme Verlag KG, Rüdigerstraße 14, 70469 Stuttgart, Germany

B
M. Linnemannstöns et al.
Paper
Synthesis
Herein, we report the synthesis and structural charac-
teristics of several tris(aryl)(phenylethyl)silanes (TAPS)
with varying degrees of fluorination; in particular with re-
spect to the occurrence of inter- vs. intramolecular -stack-
ing.
The syntheses of different fluorinated TAPS by salt elim-
ination reactions of trichloro(phenylethyl)silane with the
corresponding lithiated arenes are shown in Scheme 1. Pu-
rification by column chromatography and recrystallization
from n-hexane afforded colorless solids. The six new TAPS
were obtained in moderate to good yields. They were char-
acterized by multinuclear NMR spectroscopy, elemental
analyses and by single-crystal X-ray diffraction. Note that
silanes 2–7 are insensitive towards moisture and can be
stored under atmosphere for at several months without de-
composition.
nyl substituted silane 2 and reveals a folded structure stabi-
lized by intramolecular -stacking interactions with a cen-
troid–centroid distance dcentroids of 3.587(1) Å. The inter-
acting aryl groups are almost coplanar [angle between their
mean planes: 9.73(4)°]. However, no -stacking to neigh-
boring molecules is observed, whereas short intermolecu-
lar distances C(19)···C(25) at 3.465(3) Å and C(3)···C(12) at
3.515(3) Å are found, which are slightly above the sum of
the van der Waals (vdW) radii. The coordination geometry
at the silicon atom is almost tetrahedral (τ4 = 0.96). The
presence of many fluorine atoms leads to C···C and F···F con-
tacts in the crystal structure. The shortest C···F contact was
found for the pair C(24)···F(4) [2.950(1) Å]. The shortest F···F
contact occurred between the pair F(1)···F(9) [2.796(1) Å].
Similar results were reported by Dilman et al.11 In 2005
they presented the synthesis of several methylene bridged
tris(pentafluorophenyl)silanes and observed a folded struc-
ture for benzyltris(pentafluorophenyl)silane.
F
F
F
F
F
F
F
F
F
F F
F
ArLi/ArMgBr
2
3
4
Ar =
F
F
SiCl3
SiAr3
F
F
1
5
6
7
Scheme 1 Synthesis of the tris(aryl)(phenylethyl)silanes via salt elimi-
nation reactions of trichloro(phenylethyl)silane with the corresponding
lithiated arenes. Yields: 85% (2), 61% (3), 48% (4), 68% (5), 78% (6),
92% (7).
Figure 2 Molecular structure and primary aggregation of 2 in the crys-
talline state with an intramolecular centroid–centroid distance of
3.587(1) Å. Displacement ellipsoids are drawn at 50% probability level.
Hydrogen atoms are omitted for clarity.
Figure 3 (a) Molecular structure and primary aggregation of 3 in the
crystalline state with an intermolecular centroid–centroid distance of
3.980(1) Å. (b) The tilted T-like arrangement of compound 4. Displace-
ment ellipsoids are drawn at 50% probability level. Hydrogen atoms are
omitted for clarity.
Single crystals suitable for X-ray diffraction experi-
ments of compounds 2–7 were obtained upon slow evapo-
ration of the solvent of saturated n-hexane solutions. TAPS
2 crystallizes in the monoclinic group P21/n with four mole-
cules per unit cell. Figure 2 illustrates this pentafluorophe-
In contrast to compound 2, TAPS 3–7 crystallize in
stretched conformations stabilized by different interac-
tions. Substitution of the p-fluorine with a hydrogen atom
exclusively leads to a stretched conformation [ϕSi(1)–C(1)–
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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Table 1 Selected Structural Parameter of Silanes 2–7, 10, 11, 13, 15 and 16
Entry Structurea Xb
ϕ(SiCCC)
[°]
τ4
H···F
[Å]
C···C
[Å]
C···F
[Å]
F···F
[Å]
N···C
[Å]
N···F
[Å]
d
[Å]
c–cinter
d
[Å]
c–cintra
2
3
f
1
1
1
5
2
1
2
1
1
1
2
76.8(1)
0.96
–
3.587(1)
2.5(1) 3.465(3) 2.950(1) 2.796(1)
2.4(2) 3.395(2) 3.092(2) 2.853(1)
2.5(1) 3.303(3) 3.125(2) 2.798(2)
2.3(1) 3.279(6) 2.896(4) 2.705(1)
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
–
s
176.1(1)
0.96
0.96
3.980(1)
–
–
4
s
171.6(3)
–
5
s+f
s
75.9(3)–178.7(1)
0.99–0.95 3.670(1)–3.955(2) 3.700(2)
6
166.3(1)–175.3(1) 0.99–0.98
–
–
–
2.6(1) 3.284(3) 3.117(2)
3.352(3)
–
–
7
s
175.1(1)
148(5)–28(3)
171.2(1)
80.3(2)
0.97
–
–
–
10
11
13
15
16
s
0.96–0.95 3.473(1)–3.922(1)
–
2.6(2) 3.290(2) 3.196(2) 2.769(1)
2.4(1) 3.360(2) 2.995(1) 2.876(2)
2.5(1) 3.261(2) 3.014(2) 2.765(1)
2.6(1) 3.305(3) 2.997(2) 2.631(2)
s
0.97
0.97
0.97
3.701(1)
–
f
–
3.714(1)
3.465(1)
–
f
73.4(2)
–
s
176.5(1)–179.2(1) 0.94
3.660(1)
2.5(1) 3.323(2) 2.948(2) 2.912(2) 3.097(2) 2.935(2)
a s: stretched; f: folded.
b X: molecules per asymmetric unit.
C(2)–C(3) = 176.1(1)°] (Figure 3a). In contrast to the penta-
fluorophenyl derivative 2, TAPS 3 features a dimeric struc-
ture stabilized by intermolecular -stacking. Compared
with compound 2, the resulting distance of the mean planes
[dcentroids = 3.980(1) Å] is somewhat larger. As detected for
the pentafluorophenyl derivative, many F···F, H···F, C···C, and
C∙∙∙F contacts are observed; the shortest are summarized in
Table 1. The coordination geometry at the silicon atom is al-
most tetrahedral (τ4 = 0.96).
Compound 4 contains only three fluorine atoms per
phenyl group in a 2,4,6-substitution pattern. In contrast to
compound 3, the stretched molecular structure of TAPS 3
Figure 4 (a) Overlay of the five independent molecules of TAPS 5 revealing one folded and four stretched structures in the asymmetric unit. (b) Frag-
ment of the asymmetric unit of compound 5 revealing the folded structure and its primary aggregation with centroid–centroid distances ranging from
3.700(2) to 4.248(4) Å. (c) Asymmetric unit of compound 6 in the crystalline state, revealing a stretched structure without -stacking. (d) Molecular
structure of silane 7. Displacement ellipsoids are drawn at 50% probability level. Hydrogen atoms are omitted for clarity.
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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Synthesis
[ϕSi(1)–C(19)–C(20)–C(21) = 171.6(3)°] reveals no intra-
molecular -stacking interactions (Figure 3b). However, the
tilted T-like arrangement of TAPS 4 dimers resembles some-
what the molecular structure of pure benzene. Still the
structure of 4 is dominated by several short H/C/F···F and
C···C contacts (Table 1).
a
H
SiPh3
ClSiPh3
b
8
9
F
F
F
F
F
F
F
c
F
SiPh3
F
F
SiPh3
11
10
To assess whether there is a structural difference de-
pending on whether the fluorine atoms are distributed
evenly or half-sided at the fluorinated phenyl groups, the
crystal structure of TAPS 5 was examined. In contrast to the
previously discussed compounds, this 3,4,5-trifluorophenyl
substituted silane 5 crystallizes with five molecules per
asymmetric unit (Figure 4a).
Scheme 2 Synthesis of ethynyltriphenylsilane (9), ethynyl[(pentafluo-
rophenyl)ethynyl]triphenylsilane (10), and [(pentafluorophenyl)ethyl]-
triphenylsilane (11). Reagents and conditions: (a) ethynylmagnesium
bromide (0.5 M in THF), THF, 65 °C, 1 h, 65% (Lit.12 68%); (b) C6F5Br,
HNiPr2, CuI, Pd(PPh3)4, THF, 60 °C, 2 d, 89%; (c) H2, Pd/C, DCM, r.t., 4 h,
81%.
While four molecules reveal an overall stretched confor-
mation [ϕSi–C–C–Cphenyl = 167.1(2)–178.7(1)°], one shows
intramolecular -stacking interactions and a folded struc-
ture [ϕSi(1)–C(19)–C(20)–C(21) = 75.9(3)°] (Figure 4b).
Compared to TAPS 2, the intramolecular distance of the
centroids is slightly longer [dcentroids = 3.700(2) Å], while the
planes deviate more from co-planarity [angle between their
mean planes: 6.6(1)°] but are less twisted [9.3(2)°]. -Stack-
ing to neighboring molecules occurs for the folded struc-
ture, but only with relatively long distances between the
centroids [dcentroids = 4.079(2)–4.248(4) Å]. The four inde-
pendent molecules are mainly stabilized by intermolecular
-stacking interactions, with centroid–centroid distances
ranging from 3.670(1) Å to 3.955(2) Å and short H/C/F···F
and C···C contacts (Table 1). The coordination geometry at
all silicon atoms is almost tetrahedral (τ4 = 0.95–0.99).
The 4-fluorophenyl substituted compound 5 (Figure 4c)
and the non-fluorinated TAPS 7 (Figure 4d) both reveal no
-stacking interactions to neighboring molecules, but a tilt-
ed T-like arrangement. In contrast to the compounds with a
higher degree of fluorination, 6 reveals short H/C···F and
C···C contacts but no F···F interactions.
3.878(1) and 3.922(1) Å]. Instead -stacking of two C6F5
moieties [dcentroids = 3.473(1) and 3.522(1) Å] is observed;
these distances are about 0.4 Å shorter than in the C6H5–
C6F5 stacks. All C≡C–Si/ C≡C–CAr units [d(C≡C) = 1.198(2)–
1.203(2) Å] deviate slightly from linearity; the correspond-
ing C≡C–Si and C≡C–CAr angles range from 173.8(2)° [Si(2)–
C(27)–C(28)] to 178.7(1)° [C(1)–C(2)–C(3)]. We found earli-
er that this is a typical range for this type of compounds in
Whereas only silane 2 and partially TAPS 5 feature fold-
ed structures, we wanted to investigate this phenomenon
for the inversely fluorinated case. We therefore generated
[(pentafluorophenyl)ethyl]triphenylsilane (11) in a three-
step synthesis (Scheme 2). Starting from chlorotriphenylsi-
lane (8), ethynyltriphenylsilane (9) was obtained by using a
modification of a reported procedure.12 The pentafluoro-
phenyl group was introduced by Sonogashira coupling. Sub-
sequent palladium-catalyzed reduction of the alkyne unit
with hydrogen afforded the ethylene linking unit.
The molecular structures of silanes 10 and 11 were de-
termined by X-ray diffraction analysis of suitable single
crystals, which were grown from solution by slow evapora-
tion of the solvent (n-hexane). Compound 10 crystallizes in
the monoclinic space group P2/n with eight molecules per
unit cell (Figure 5). The asymmetric unit comprises two in-
dependent molecules with very similar structures. The
chain-like structures are stabilized by -stacking interac-
tions, but unlike TAPS 2, 3, and 5, not only by an interplay of
Figure 5 Molecular structure and aggregation of 10 in the crystalline
state with centroid–centroid distances ranging from 3.473(1) Å to
3.922(1) Å. Displacement ellipsoids are drawn at 50% probability level.
Hydrogen atoms are omitted for clarity.
a fluorinated and a non-fluorinated aryl group [dcentroids
=
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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Synthesis
the solid state.13 As already observed for other fluorinated
TAPS, the molecule seeks additional stabilization by H/F···F
contacts.
CH3
F
F
F
F
H3C
a
F
The molecular structure of the hydrogenated species 11
is depicted in Figure 6. All bond lengths and angles are
found to be in the expected ranges. In contrast to its in-
versely fluorinated counterpart 2, the structure of 11 in the
crystal is not folded [ϕSi(1)–C(19)–C(20)–C(21) =
171.2(3)°], but receives stabilization by intramolecular -
stacking interactions [dcentroids = 3.701(1) Å]; this leads to
the formation of dimeric structures. The opposing aryl
groups are folded by 9.9(1)° and twisted by 38.2(2)° to each
other. However, no pronounced -stacking to neighboring
dimers is observed, but remarkably short H/C/F···F contacts
are noted, with some being below the sum of the
van der Waals radii (Table 1).
SiCl3
Si
C6F5
C6F5
12
13
F
F
F
a
F
F
SiCl3
Si
C6F5
C6F5
14
15
Scheme 3 Synthesis of (4-methylphenethyl)tris(pentafluorophenyl)si-
lane (13) and [2-(naphth-2-yl)ethyl]tris(pentafluorophenyl)silane (15)
starting from the corresponding trichlorosilanes 12 or 14. Reagents and
conditions: (a) bromopentafluorobenzene, n-butyllithium (1.6 M in n-
hexane), diethyl ether, –78 °C (1 h) to r.t. (12 h), 82% (13), 76% (15).
longer and the angles between the mean planes are wider
[8.1(1)°]. This may be due to the steric demand of the meth-
yl groups. As observed for TAPS 2, no pronounced intermo-
lecular -stacking to neighboring molecules occurs, but re-
markably short interatomic distances are detected. For in-
stance, these strong contacts arise between C(18)···C(19)
[d = 3.261(1) Å], and C(7)···C(12) [d = 3.481(2) Å], with the
first distances being below the sum of the corresponding
van der Waals radii and are slightly shorter than the con-
tacts observed for compound 2.
Figure 6 Molecular structure and aggregation of 11 in the crystalline
state with an intramolecular centroid–centroid distance of 3.701(1) Å.
Displacement ellipsoids are drawn at 50% probability level. Hydrogen
atoms are omitted for clarity.
To date, it seems that only compounds with a tris(pen-
tafluorophenyl)silyl group linked by an ethylene unit to a
phenyl ring offer folded structures in the crystalline state.
By varying the phenyl unit with other aromatic groups, we
wanted to investigate the structural properties of the re-
sulting silanes. As shown in Scheme 3, two tris(pentafluo-
ro)phenyl-substituted TAPS were synthesized, bearing a 4-
tolyl (13) or a 2-naphthyl (15) group. The synthesis of the
trichlorosilane precursors 12 and 14 was published by
Wang et al.14 The introduction of the pentafluorophenyl
groups as well as the purification and isolation process are
analogous to those of TAPS 2–7.
Figure 7 Molecular structure and primary aggregation of 13 in the
crystalline state with an intramolecular centroid–centroid distance of
3.714(1) Å. Displacement ellipsoids are drawn at 50% probability level.
Hydrogen atoms are omitted for clarity.
Compound 13 crystallizes in the triclinic space group Pī
(Figure 7) with two molecules per unit cell and reveals a
folded structure [ϕSi(1)–C(1)–C(2)–C(3) = 80.3(2)°]. Com-
pared to silane 2, the centroid–centroid distance of the in-
teracting aryl moieties with dcentroids = 3.714(1) Å is slightly
The molecular structure of the naphthyl substituted
TAPS 15 (Figure 8) is very similar to both tris(pentafluo-
ro)phenylsilyl functionalized systems, 2 and 13. As indicat-
ed by the torsion angle ϕSi(1)–C(19)–C(20)–C(21) at
73.4(2)° the structure features a folded conformation. The
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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result is a remarkably short centroid–centroid distance be-
tween the mean planes of C(13)–C(14)–C(15)–C(16)–
C(17)–C(18) and C(3)–C(4)–C(5)–C(10)–C(11)–C(12) of
3.465(1) Å, which is significantly shorter than the distances
observed in 2 and 13. In comparison to the compounds dis-
cussed above, this structure contains no significant inter-
molecular -stacking interaction, even though the naphthyl
group offers enough surface area for further interactions.
As indicated by the torsion angles ϕC(3)–C(4)–C(5)–C(6) at
173.3(2)° and ϕC(9)–C(10)–C(11)–C(12) at 175.8(2)° the
naphthyl unit suffers a distortion from planarity, which
may arise from the -stacking interaction.
Compound 16 crystallizes in the triclinic space group Pī
with four molecules per unit cell (Figure 9). The asymmetric
unit consists of two molecules, both featuring a stretched
conformation [ϕSi(1)–C(1)–C(2)–C(3) at 176.5(1)° and
ϕSi(2)–C(24)–C(25)–C(26) at 179.2(1)°]. In contrast to the
trispentafluorophenylsilyl-substituted compounds, 16 does
not reveal intramolecular -stacking. Instead intermolecu-
lar -stacking interactions of two NC4F4 groups
[dcentroids = 3.660(1) Å] are found. In addition, remarkably
short H/C/N/F···F and N···C contacts are observed. The stron-
gest contacts of each kind are below the sum of the
van der Waals radii (Table 1).
Figure 8 Molecular structure of 15 in the crystalline state with an in-
tramolecular centroid–centroid distance of 3.464(1) Å. Displacement
ellipsoids are drawn at 50% probability level. Hydrogen atoms are omit-
ted for clarity.
Figure 9 Molecular structure of 16 in the crystalline state. Displace-
ment ellipsoids are drawn at 50% probability level. Hydrogen atoms are
omitted for clarity.
In conclusion, a series of trisaryl(arylethyl)silanes was
synthesized and investigated regarding their molecular
structures in the crystalline state. By varying the degree of
fluorination and using the flexible C–C–Si linking unit, dif-
ferent structural motifs were observed. Intramolecular -
stacking and an associated folded structure are observed for
compounds with tris(pentafluorophenyl)silyl groups. Suc-
cessive reduction of the number of fluorine atoms consis-
tently leads to stretched structures. However, for the in-
versely fluorinated ([pentafluorophenyl]ethyl)triphenylsi-
lane no analogous result is observed. The molecular
structure in the crystalline state of a tetrafluoropyridyl
functionalized system is dominated by strong H/C/N/F···F
and N···C contacts and does not reveal any prominent -
stacking at all.
Since only the pentafluorophenyl substituted silanes
lead to folded structures, the question arose, whether per-
fluorinated heteroaromatics would lead to similar struc-
tures. Recently, Schwabedissen et al. investigated the struc-
ture of several 1:1 co-crystals containing p-halotetrafluoro-
pyridines and benzene.15 They showed that the columnar
structures had high similarities to the co-crystal C6H6·C6F6.1
As depicted in Scheme 4, we consequently synthesized the
tetrafluoropyridyl substituted TAPS 16 by salt elimination
starting from chlorosilane 2. This is, to our knowledge, the
first known tris(2,3,4,5-tetrafluoropyridyl)silane derivative
reported to date. In contrast to the TAPS presented, TAPS 16
seems to be labile towards moisture. This is probably due to
the stronger electron-withdrawing character of the tetra-
fluoropyridyl substituent compared to C6F5.16
N
F
F
F
F
1-Bromo-2,3,4,5,6-pentafluorobenzene, 1-bromo-3,4,5-trifluoroben-
zene, 1,2,4,5-tetrafluorobenzene, 1,3,6-trifluorobenzene, 1-bromo-4-
fluorobenzene, 2,3,5,6-tetrafluopyridine, CuI, tetrakis(triphenylphos-
phane)palladium(0) (all purchased from Fluorochem), n-butyllithium
(1.6 M in n-hexane), 1-bromobenzene (both from Arcos Organics),
ethynylmagnesium bromide (0.5 M in THF from Fisher Scientific),
chlorotriphenylsilane (from TCI) and Mg turnings (from Merck) were
used without further purification. All reactions using metal organic
reagents were carried out under a dry atmosphere of N2 using stan-
dard Schlenk techniques in anhydrous diethyl ether (DE) or THF
a
SiCl3
Si
C5NF4
C5NF4
1
16
Scheme 4 Synthesis of (phenylethyl)tris(2,3,4,5-tetrafluoropyridyl)si-
lane (16) starting from trichlorophenylethylsilane (1). Reagents and con-
ditions: (a) tetrafluoropyridine, n-butyllithium (1.6 M in n-hexane), DE,
–78 °C (4 h) to r.t. (12 h), 78%.
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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Synthesis
(dried over LiAlH4 or K and freshly distilled before use). Column chro-
matography was performed on silica gel 60 (0.040–0.063 mm). NMR
spectra were recorded with a Bruker Avance 300, a Bruker DRX 500,
or a Bruker Avance III 500 instrument at 298 K and referenced to sol-
vent (CDCl3: 1H NMR  = 7.26 ppm, 13C NMR  = 77.16 ppm; C6D6: 1H
NMR  = 7.16 ppm, 13C NMR  = 128.06 ppm) or referenced externally
AT-IR: 3118, 3082, 3059, 3033, 2903, 2541, 1820, 1721, 1600, 1460,
1384, 1358, 1267, 1227, 1171, 1134, 1113, 1028, 1005, 901, 860, 853,
767, 723, 707, 693, 671, 573, 541, 522, 499, 449, 438, 428 cm–1
.
1H NMR (500 MHz, C6D6):  = 7.05 (m, 5 H, ArH), 6.20 (tt, JF,H = 9.2 Hz,
JF,H = 7.1 Hz, 3 H, ArFH), 2.66 (m, 2 H, CH2CH2Si), 2.0 (m, 2 H, CH2CH2Si).
13C{1H} NMR (126 MHz, C6D6):  = 149.2 (Ar–C6HF4), 146.1 (Ar–C6HF4),
143.0 (Ar–C6H5), 128.9 (Ar–C6H5), 128.1 (Ar–C6H5), 126.5 (Ar–C6H5),
111.2 (Ar–C6F5), 109.9 (Ar–C6F5), 29.8 (CH2CH2Si), 17.3 (CH2CH2Si).
19F{1H} NMR (470 MHz, C6D6):  = 127.6 (m), –137.2 (m).
29Si{1H} NMR (99 MHz, C6D6):  = 23.3.
MS (EI, 70 eV): m/z = 580.1 [M]+, 431.1 [M – C6HF4]+.
HRMS: m/z calcd for C26H12F12Si+: 580.05112; found: 580.05277.
(
29Si NMR: TMS). Elemental analyses were performed with a Euro EA
Elemental analyzer. EI mass spectra were recorded with an AutospecX
magnetic sector mass spectrometer with EBE geometry (Vacuum
Generators, Manchester UK) equipped with a standard EI source;
samples were introduced with a push rod in aluminum crucibles; ions
were accelerated by 8 kV.
Introduction of Arenes by Lithiation; General Procedure
Anal. Calcd (%) for C26H12F12Si: C, 53.80; H, 2.08. Found: C, 53.91; H,
2.09.
The corresponding HAr/BrAr was dissolved in diethyl ether and
cooled to –78 °C. A syringe was used to slowly add n-butyllithium
(1.6 M in n-hexane, 1 equiv). After complete addition, the reaction
mixture was stirred for 1 h. The respective trichlorosilane was then
added at –78 °C by using a syringe and the solution was slowly heated
to r.t. overnight. After hydrolyzing with water and extraction of the
aqueous layer with CH2Cl2, the combined organic phases were dried
with Na2SO4. The solvent was removed under reduced pressure and
the crude product was purified by column chromatography on silica
gel and subsequent crystallization.
Phenylethyltris(2,4,6-trifluorophenyl)silane (4)
Prepared according to the General Procedure using 1,3,5-trifluoro-
benzene (1.3 mL, 13 mmol, 3 equiv), diethyl ether (100 mL), n-butyl-
lithium (1.6 M in n-hexane, 7.9 mL, 13 mmol, 3 equiv) and tri-
chloro(phenylethyl)silane (1.0 g, 4.2 mmol, 1 equiv). Column chroma-
tography (n-pentane) and recrystallization from n-hexane afforded 4
as colorless crystals.
Yield: 1.1 g (2.0 mmol, 48%).
Tris(pentafluorophenyl)(phenylethyl)silane (2)
AT-IR: 3101, 3066, 3029, 2935, 1688, 1626, 1601, 1578, 1514, 1496,
1475, 1455, 1408, 1325, 1282, 1177, 1161, 1117, 1090, 1069, 1010,
999, 894, 840, 760, 733, 693, 640, 617, 585, 572, 558, 514, 490, 463,
Prepared according to the General Procedure using 1-bromo-
2,3,4,5,6-pentafluorobenzene (1.6 mL, 13 mmol, 3 equiv), diethyl
ether (100 mL), n-butyllithium (1.6 M in n-hexane, 7.9 mL, 13 mmol,
3 equiv) and trichloro(phenylethyl)silane (1.0 g, 4.2 mmol, 1 equiv).
Column chromatography (n-pentane) and recrystallization from n-
hexane afforded 2 as colorless crystals.
439, 418 cm–1
.
1H NMR (500 MHz, C6D6):  = 7.15 (m, 4 H, ArH), 7.06 (m, 1 H, ArH),
6.16 (m, 3 H, ArFH), 2.79 (m, 2 H, CH2CH2Si), 2.09 (m, 2 H, CH2CH2Si).
13C{1H} NMR (126 MHz, C6D6):  = 167.6 (Ar–C6H2F3), 165.6 (Ar–
C6H2F3), 144.3 (Ar–C6H5), 128.9 (Ar–C6H5), 128.2 (Ar–C6H5), 126.3 (Ar–
C6H5), 105.3 (Ar–C6H2F3), 100.5 (Ar–C6H2F3), 30.3 (CH2CH2Si), 18.3
(CH2CH2Si).
19F{1H} NMR (470 MHz, C6D6):  = 94.0 (m), –103.9 (m).
29Si{1H} NMR (99 MHz, C6D6):  = 25.4.
MS (EI, 70 eV): m/z = 395.0 [M – C6H2F3]+.
Yield: 2.3 g (3.6 mmol, 85%).
AT-IR: 3030, 2917, 2866, 1643, 1603, 1585, 1518, 1455, 1406, 1377,
1288, 1260, 1176, 1086, 997, 966, 928, 897, 851, 821, 760, 747, 729,
713, 697, 675, 631, 622, 602, 587, 570, 550, 520, 512, 483, 448, 440,
420 cm–1
.
1H NMR (500 MHz, C6D6):  = 7.11 (m, 2 H, ArH), 7.05 (m, 3 H, ArH),
2.62 (m, 2 H, CH2Si), 1.91 (m, 2 H, CH2Ph).
13C{1H} NMR (126 MHz, C6D6):  = 149.5 (Ar–C6F5), 143.7 (Ar–C6F5),
142.5 (Ar–C6H5), 137.8 (Ar–C6F5), 129.0 (Ar–C6H5), 128.4 (Ar–C6H5),
126.8 (Ar–C6H5), 104.5 (Ar–C6F5), 29.7 (Ph–CH2), 17.3 (Si–CH2).
Anal. Calcd (%) for C26H15F9Si: C, 59.32; H, 2.87. Found: C, 59.11; H,
2.73.
19F{1H} NMR (470 MHz, C6D6):  = 126.9 (m, 2 F, o-F), –146.5 (m, p-F),
–159.5 (m, 2 F, m-F).
Phenylethyltris(3,4,5-trifluorophenyl)silane (5)
To magnesium turnings (306 mg, 12.6 mmol, 3 equiv) in tetrahydro-
furan (10 mL) a few drops of a solution of 1-bromo-3,4,5-trifluoro-
benzene (1.50 mL, 12.6 mmol, 3 equiv) in tetrahydrofuran (30 mL)
were added until cloudiness and darkening showed the beginning of
the Grignard reaction. The residual solution of 1-bromo-3,4,5-trifluo-
robenzene was added within 10 min and the reaction mixture was
heated at reflux for 1 h until full consumption of magnesium was ob-
served. At ambient temperature, trichloro(phenylethyl)silane (1.0 g,
4.2 mmol, 1 equiv) was added by using a syringe and the reaction
mixture was heated at reflux for 1 h and stirred at r.t. overnight. After
hydrolyzing with water (30 mL) and extraction of the aqueous layer
with CH2Cl2 (3 × 50 mL), the combined organic phases were dried
with Na2SO4. The solvent was removed under reduced pressure, re-
sulting in the formation of a colorless oil, which was purified by col-
umn chromatography on silica gel to give a colorless solid. Crystalliza-
tion from n-hexane afforded 5 as colorless crystals.
29Si{1H} NMR (99 MHz, C6D6):  = 23.5.
Anal. Calcd (%) for C26H9F15Si: C, 49.22; H, 1.42. Found: C, 49.70; H,
1.43.
Phenylethyltris(2,3,5,6-tetrafluorophenyl)silane (3)
Prepared according to the General Procedure using 1,2,4,5-tetrafluo-
robenzene (1.3 mL, 13 mmol, 3 equiv), diethyl ether (100 mL), n-bu-
tyllithium (1.6 M in n-hexane, 7.9 mL, 13 mmol, 3 equiv) and tri-
chloro(phenylethyl)silane (1.0 g, 4.2 mmol, 1 equiv). Column chroma-
tography (n-pentane) and recrystallization from n-hexane afforded 3
as colorless crystals.
Yield: 2.5 g (2.6 mmol, 61%).
Yield: 1.5 g (2.9 mmol, 68%).
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
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Synthesis
AT-IR: 3063, 3032, 2926, 2888, 2859, 2357, 1605, 1579, 1519, 1495,
1453, 1397, 1314, 1283, 1271, 1234, 1221, 1183, 1123, 1092, 1031,
905, 890, 856, 759, 746, 732, 712, 696, 681, 611, 611, 566, 530, 510,
1H NMR (500 MHz, C6D6):  = 7.59 (m, 6 H, ArH), 7.19 (m, 9 H, ArH),
7.14 (m, 2 H, ArH), 7.05 (m, 6 H, ArFH), 2.81 (m, 2 H, CH2CH2Si), 1.69
(m, 2 H, CH2CH2Si).
13C{1H} NMR (126 MHz, C6D6):  = 145.2 (Ar–C), 136.1 (Ar–C), 135.4
(Ar–C), 129.8 (Ar–C), 128.7 (Ar–C), 128.3 (Ar–C), 128.2 (Ar–C), 126.0
(Ar–C), 30.6 (CH2CH2Si), 16.2 (CH2CH2Si).
489, 468, 432, 413 cm–1
.
1H NMR (500 MHz, CDCl3):  = 7.30 (m, 2 H, ArH), 7.15 (m, 2 H, ArH),
2
7.23 (m, 1 H, ArH), 7.03 (t JF,H = 6.7 Hz, 6 H, ArFH), 2.77 (m, 2 H,
CH2CH2Si), 1.74 (m, 2 H, CH2CH2Si).
29Si{1H} NMR (99 MHz, C6D6):  = 10.9.
13C {1H} NMR (126 MHz, CDCl3):  = 151.8 (Ar–C6H2F3), 142.8 (Ar–
C6H5), 141.5 (Ar–C6H2F3), 128.8 (Ar–C6H5), 128.7 (Ar–C6H2F3), 127.8
(Ar–C6H5), 126.6 (Ar–C6H5), 119.1 (Ar–C6H2F3), 29.6 (CH2CH2Si), 14.8
(CH2CH2Si).
MS (EI, 70 eV): m/z = 285.9 [M – C8H9]+, 182.9 [M – C14H14]+.
Anal. Calcd (%) for C26H24Si: C, 85.66; H, 6.64. Found: C, 85.48; H, 6.53.
[(Pentafluorophenyl)ethynyl]triphenylsilane (10)
2
19F{1H} NMR (470 MHz, CDCl3):  = 132.5 (d, JF,F = 19.9 Hz, 6 F),
To a degassed solution of ethynyltriphenylsilane (1.0 g, 3.5 mmol,
1 equiv), diisopropylamine (1.4 mL, 10 mmol, 2 equiv) and bro-
mopentafluorobenzene (0.5 mL, 4 mmol, 1 equiv) in THF (15 mL), a
mixture of [Pd(PPh3)4] (100 mg, 0.12 mmol, 3.0 mol%) and CuI (50 mg,
0.30 mmol, 7.5 mol%) was added. The solution was stirred at 60 °C for
4 d and the resulting brown suspension was filtered to give an orange
solution. After removing the solvent under reduced pressure, the
crude brown solid was purified by filtration through silica gel with n-
pentane to give a colorless solid. Crystallization from n-hexane af-
forded 10 as colorless crystals.
–156.1 (t, 2JF,F = 19.9 Hz, 3 F)
29Si{1H} NMR (99 MHz, CDCl3):  = 8.2.
MS (EI, 70 eV): m/z = 525.7 [M – C6H5F]+, 420.8 [M – C8H9]+.
Anal. Calcd (%) for C26H15F9Si: C, 59.32; H, 2.87. Found: C, 59.40; H,
2.92.
Tris(4-fluorophenyl)(phenylethyl)silane (6)
Prepared according to the General Procedure using 1-bromo-4-fluo-
robenzene (1.4 mL, 13 mmol, 3 equiv), diethyl ether (100 mL), n-bu-
tyllithium (1.6 M in n-hexane, 7.9 mL, 13 mmol, 3 equiv) and tri-
chloro(phenylethyl)silane (1.0 g, 4.3 mmol, 1 equiv). Column chroma-
tography (n-pentane) and recrystallization from n-hexane afforded 6
as colorless crystals.
Yield: 1.4 g (3.1 mmol, 89%).
AT-IR: 3067, 3023, 3003, 2962, 2174, 1647, 1588, 1567, 1517, 1497,
1427, 1372, 1260, 1187, 1112, 1032, 979, 867, 855, 800, 740, 696,
660, 580, 568, 501, 469, 460, 453, 431, 420 cm–1
.
Yield: 1.4 g (3.3 mmol, 78%).
1H NMR (500 MHz, C6D6):  = 7.84 (m, 6 H, ArH), 7.19 (m, 9 H, ArH).
AT-IR: 3061, 3026, 2927, 2863, 1907, 1884, 1581, 1496, 1454, 1385,
1224, 1160, 1103, 1012, 896, 820, 765, 724, 699, 687, 644, 595, 560,
517, 451, 424.
13C{1H} NMR (126 MHz, C6D6):  = 147.9 (Ar–C6F5), 142.0 (Ar–C6F5),
137.6 (Ar–C6F5), 136.0 (Ar–C6H5), 132.8 (Ar–C6H5), 130.7 (Ar–C6H5),
128.6 (Ar–C6H5), 105.0 (C≡C–Si), 99.9 (Ar–C6F5), 92.2 (C≡C–Si).
1H NMR (500 MHz, C6D6):  = 7.24 (m, 6 H, ArFH), 7.19 (m, 2 H, ArH),
7.06 (m, 3 H, ArH), 6.88 (m, 6 H, ArFH), 2.65 (m, 2 H, CH2CH2Si), 1.50
(m, 2 H, CH2CH2Si).
13C{1H} NMR (126 MHz, C6D6):  = 164.6 (Ar–C6H4F), 144.7 (Ar–C6H5),
137.9 (Ar–C6H4F), 130.3 (Ar–C6H4F), 128.8 (Ar–C6H5), 128.1 (Ar–C6H5),
126.3 (Ar–C6H5), 115.6 (Ar–C6H4F), 30.4 (CH2CH2Si), 16.1 (CH2CH2Si).
19F{1H} NMR (470 MHz, C6D6):  = 135.8 (m, 2 F, o-F), –152.1 (m, p-F),
–162.2 (m, 2 F, m-F).
29Si{1H} NMR (99 MHz, C6D6):  = 27.6.
MS (EI, 70 eV): m/z = 372.6 [M – C6H5]+.
Anal. Calcd (%) for C26H15F5Si: C, 69.32; H, 3.36; F, 21.09; Si, 6.23.
Found: C, 69.58; H, 3.67; F, 20.53; Si, 6.11.
19F{1H} NMR (470 MHz, C6D6):  = 145.7 (s).
29Si{1H} NMR (99 MHz, C6D6):  = 11.1.
[(Pentafluorophenyl)ethyl]triphenylsilane (11)
MS (EI, 70 eV): m/z = 322.1 [M – C6H5F]+, 313.1 [M – C8H9]+.
HRMS: m/z calcd for C26H21F3Si+: 418.13591; found: 418.13563.
To a solution of [(pentafluorophenyl)ethynyl]triphenylsilane (100 mg,
0.22 mmol), in MeOH (15 mL), one spatula of Pd(C) (10 wt.% loading)
was added. The black suspension was stirred at ambient temperature
for 13 h under a continuous flow of hydrogen. After filtration and re-
moving the solvent under reduced pressure, [(pentafluorophenyl)eth-
yl]triphenylsilane was obtained as colorless crystals.
Anal. Calcd (%) for C26H21F3Si: C, 74.61; H, 5.06. Found: C, 74.90; H,
5.05.
Phenylethyltriphenylsilane (7)
Yield: 81 mg (0.18 mmol, 81%).
Prepared according to the General Procedure using bromobenzene
(1.3 mL, 13 mmol, 3 equiv), diethyl ether (100 mL), n-butyllithium
(1.6 M in n-hexane, 7.9 mL, 13 mmol, 3 equiv) and trichloro(phenyl-
ethyl)silane (1.0 g, 4.3 mmol, 1 equiv). Column chromatography (n-
pentane) and recrystallization from n-hexane afforded 7 as colorless
crystals.
AT-IR: 3030, 3051, 3011, 2929, 1658, 1588, 1519, 1499, 1427, 1321,
1294, 1262, 1216, 1181, 1150, 1111, 995, 977, 891, 821, 773, 742,
696, 667, 505, 487, 477, 459 cm–1
.
1H NMR (500 MHz, C6D6):  = 7.57 (m, 6 H, ArH), 7.19 (m, 9 H, ArH),
2.62 (m, 2 H, CH2CH2Si), 1.49 (m, 2 H, CH2CH2Si).
Yield: 1.4 g (3.9 mmol, 92%).
13C{1H} NMR (126 MHz, C6D6):  = 144.9 (Ar–C6F5), 139.6 (Ar–C6F5),
137.6 (Ar–C6F5), 135.9 (Ar–C6H5), 134.5 (Ar–C6H5), 130.1 (Ar–C6H5),
128.5 (Ar–C6H5), 117.9 (Ar–C6F5), 17.5 (CH2CH2Si), 14.4 (CH2CH2Si).
19F{1H} NMR (470 MHz, C6D6):  = 145.7 (m, 2 F, o-F), –159.2 (m, p-F),
–163.5 (m, 2 F, m-F).
AT-IR: 3063, 3024, 2995, 2931, 2898, 2878, 1600, 1584, 1487, 1452,
1425, 1384, 1328, 1306, 1259, 1173, 1131, 1107, 1065, 1027, 996,
914, 893, 762, 739, 727, 712, 696, 669, 620, 574, 507, 483, 434,
422 cm–1
.
29Si{1H} NMR (99 MHz, C6D6):  = 11.3.
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J

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M. Linnemannstöns et al.
Paper
Synthesis
Anal. Calcd (%) for C26H19F5Si: C, 68.71; H, 4.21; F, 20.90; Si, 6.18.
Found: C, 68.45; H, 4.39; F, 21.01; Si, 6.06.
solution was allowed to slowly warm to ambient temperature and
stirred for 12 h. The resulting yellow/brownish suspension was dried
in vacuum and suspended in anhydrous n-hexane (100 mL). The solid
was filtered off and washed with anhydrous diethyl ether (100 mL).
The diethyl ether was removed under reduced pressure to give a pale-
yellow solid. Recrystallization from anhydrous diethyl ether afforded
16 as colorless crystals.
(4-Methylphenethyl)tris(pentafluorophenyl)silane (13)
Prepared according to the General Procedure using 1-bromo-
2,3,4,5,6-pentafluorobenzene (1.6 mL, 13 mmol, 3 equiv), diethyl
ether (100 mL), n-butyllithium (1.6 M in n-hexane, 7.9 mL, 13 mmol,
3 equiv) and trichloro(4-methylphenethyl)silane (1.1 g, 4.3 mmol,
1 equiv). Column chromatography (n-pentane) and recrystallization
from n-hexane afforded 13 as colorless crystals.
Yield: 3.8 g (6.5 mmol, 78%).
AT-IR: 3029, 2963, 1639, 1603, 1465, 1440, 1423, 1397, 1380, 1295,
1260, 1231, 1186, 1141, 1097, 1024, 992, 941, 936, 913, 903, 877,
862, 801, 764, 732, 715, 693, 585, 554, 534, 490, 462, 445, 434 cm–1
.
Yield: 2.2 g (3.4 mmol, 82%).
1H NMR (500 MHz, C6D6):  = 7.01 (m, 3 H, ArH), 6.87 (m, 2 H, ArH),
2.50 (m, 2 H, CH2Si), 1.76 (m, 2 H, CH2Ph).
AT-IR: 2929, 2895, 2874, 1642, 1607, 1582, 1518, 1455, 1398, 1378,
1314, 1286, 1167, 1091, 1030, 964, 907, 856, 838, 819, 802, 778, 759,
720, 693, 671, 629, 619 cm–1
.
13C{1H} NMR (126 MHz, C6D6):  = 144.4 (Ar–C5NF4), 144.0 (Ar–C5NF4),
141.0 (Ar–C6H5), 128.9 (Ar–C6F5), 128.0 (Ar–C6H5), 127.4 (Ar–C6H5),
123.1 (Ar–C6H5), 104.6 (Ar–C6F5), 29.3 (Ph–CH2), 29.0 (Ph–CH3), 14.8
(Si–CH2).
19F{1H} NMR (470 MHz, C6D6):  = 89.1 (m, 6 F), –128.6 (m, 6 F).
29Si{1H} NMR (99 MHz, C6D6):  = 24.7.
1H NMR (500 MHz, C6D6):  = 6.96 (m, 4 H, ArH), 2.65 (m, 2 H, CH2Si),
2.13 (s, 3 H, PhCH3), 1.91 (t, JH,H = 8.3 Hz, 2 H, CH2CPh).
13C{1H} NMR (126 MHz, C6D6):  = 149.4 (Ar–C6F5), 143.7 (Ar–C6F5),
149.3 (Ar–C6H4), 137.7 (Ar–C6F5), 136.3 (Ar–C6H4), 129.6 (Ar–C6H4),
128.0 (Ar–C6H4), 104.6 (Ar–C6F5), 29.3 (Ph–CH2), 29.9 (Ph–CH3), 17.3
(Si–CH2).
Anal. Calcd (%) for C23H9F12N3Si: C, 47.53; H, 1.55; N, 7.20. Found: C,
48.34; H, 1.81; N, 7.03.
19F{1H} NMR (470 MHz, C6D6):  = 126.8 (m, 6 F, o-F), –146.6 (m, 3 F,
p-F), –159.6 (m, 2 F, m-F).
29Si{1H} NMR (99 MHz, C6D6):  = 23.7.
Funding Information
Anal. Calcd (%) for C27H11F15Si: C, 50.01; H, 1.71. Found: C, 50.27; H,
1.34.
This work was funded by Deutsche Forschungsgemeinschaft (DFG,
grant no. Mi477/28-2, project number 271386299).
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[2-(Naphth-2-yl)ethyl]tris(pentafluorophenyl)silane (15)
Prepared according to the General Procedure using 1-bromo-
2,3,4,5,6-pentafluorobenzene (1.0 mL, 8.0 mmol, 3 equiv), diethyl
ether (100 mL), n-butyllithium (1.6 M in n-hexane, 5.0 mL, 8.0 mmol,
3 equiv) and trichloro[2-(naphth-2-yl)ethyl]silane (0.78 g, 2.7 mmol,
1 equiv). Column chromatography (n-pentane) and recrystallization
from n-hexane afforded 15 as colorless crystals.
Acknowledgment
The authors thank Dipl. Ing. Klaus-Peter Mester and Marco Wißbrock
for recording NMR spectra, as well as Barbara Teichner for elemental
analyses.
Yield: 1.4 g (2.1 mmol, 76%).
AT-IR: 3069, 2968, 2933, 2916, 2862, 1644, 1518, 1461, 1404, 1382,
1373, 1289, 1178, 1156, 1142, 1083, 967, 924, 898, 854, 819, 782,
Supporting Information
766, 758, 740, 725 cm–1
.
Supporting information for this article is available online at
1H NMR (500 MHz, C6D6):  = 7.60 (m, 3 H, ArH), 7.43 (s, 1 H, ArH),
7.26 (m, 2 H, ArH), 7.18 (dd, JH,H = 8.47 Hz, JH,H = 1.83 Hz, 2 H, ArH),
2.83 (m, 2 H, CH2Si), 2.00 (m, 2 H, CH2–Naph).
13C{1H} NMR (126 MHz, C6D6):  = 149.4 (Ar–C6F5), 143.7 (Ar–C6F5),
139.6 (Ar–C10H7), 137.7 (Ar–C6F5), 129.0 (Ar–C6H5), 134.1 (Ar–C10H7),
132.8 (Ar–C10H7), 128.8 (Ar–C10H7), 128.0 (Ar–C10H7), 126.7 (Ar–C10H7),
126.4 (Ar–C10H7), 126.1 (Ar–C10H7), 104.5 (Ar–C6F5), 30.0 (Naph–CH2),
16.9 (Si–CH2).
19F{1H} NMR (470 MHz, C6D6):  = 126.8 (m, 2 F, o-F), –146.5 (m, p-F),
–159.6 (m, 2 F, m-F).
29Si{1H} NMR (99 MHz, C6D6):  = 23.8.
https://doi.org/10.1055/s-0039-1690785.
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References
(1) Patrick, C. P.; Prosser, G. S. Nature 1960, 187, 1021.
(2) (a) Cox, E. G.; Cruickshank, D. E. J.; Smith, J. A. S. Proc. R. Soc.
London, Ser. A 1958, 247, 1. (b) Boden, N.; Davis, P. P.; Stam, C.
H.; Wesselink, G. A. Mol. Phys. 1973, 25, 81.
(3) (a) Overell, J. S. W.; Pawley, G. S. Acta Crystallogr., Sect. B: Struct.
Sci. 1982, 38, 1966. (b) Williams, H.; Cockcroft, J. K.; Fitch, A. N.
Angew. Chem., Int. Ed. Engl. 1992, 31, 1655; Angew. Chem. 1992,
104, 1666.
(4) (a) Williams, J. H. Acc. Chem. Res. 1993, 26, 593. (b) Dahl, T.;
Kozma, D.; Ács, M.; Weidlein, J.; Schnöckel, H.; Paulsen, G. B.;
Nielsen, I.; Olsen, C. E.; Pedersen, C.; Stidsen, C. E. Acta Chem.
Scand. 1994, 48, 95. (c) Cabaco, M. I.; Danten, Y.; Besnard, M.;
Guissani, Y.; Guillot, B. Chem. Phys. Lett. 1996, 262, 120.
(d) Collings, J. C.; Roscoe, K. P.; Robins, E. G.; Batsanov, A. S.;
Stimson, L. M.; Howard, J. A. K.; Clark, S. J.; Marder, T. B. New J.
Chem. 2002, 26, 1740. (e) Battaglia, M. R.; Buckingham, A. D.;
Williams, J. H. Chem. Phys. Lett. 1981, 78, 421.
Anal. Calcd (%) for C30H11F15Si: C, 52.64; H, 1.62. Found: C, 52.24; H,
1.60.
(Phenylethyl)tris(2,3,4,5-tetrafluoropyridyl)silane (16)
To a solution of tetrafluoropyridine (2.5 mL, 25 mmol, 3 equiv) in an-
hydrous diethyl ether (100 mL) at –78 °C, n-butyllithium (1.6 M in n-
hexane, 15.6 mL, 25 mmol, 3 equiv) was added. After 1 h, trichloro-
phenylethylsilane (2.0 g, 8.3 mmol, 1 equiv) was added dropwise by
using a syringe over a period of 5 min. After complete addition, the
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J
M. Linnemannstöns et al.
Paper
Synthesis
(5) (a) Sinnokrot, M. O.; Sherrill, C. D. J. Am. Chem. Soc. 2004, 126,
7690. (b) Gung, B. W.; Amicangelo, J. C. J. Org. Chem. 2006, 71,
9261. (c) Tsuzuki, S.; Uchimaru, T.; Mikami, M. J. Phys. Chem. A
2006, 110, 2027. (d) Huber, R. G.; Margreiter, M. A.; Fuchs, J. E.;
von Grafenstein, S.; Tautermann, C. S.; Liedl, K. R.; Fox, T.
J. Chem. Inf. Model. 2014, 54, 1371.
(6) Meyer, E. A.; Castellano, R. K.; Diederich, F. Angew. Chem. Int. Ed.
2003, 42, 1210; Angew. Chem. 2003, 115, 1244.
(7) Lerman, C. A. J. Mol. Biol. 1961, 3, 18.
(11) Dilman, A. D.; Arkhipov, D. E.; Korlyukov, A. A.; Ananikov, V. P.;
Danilenko, V. M.; Tartakovsky, V. A. J. Org. Chem. 2005, 690,
3680.
(12) Ochida, A.; Ito, H.; Sawamura, M. J. Am. Chem. Soc. 2006, 128,
16486.
(13) (a) Niermeier, P.; Lamm, J.-H.; Peters, J.-H.; Neumann, B.;
Stammler, H.-G.; Mitzel, N. W. Synthesis 2019, 51, 1623.
(b) Niermeier, P.; Lamm, J.-H.; Mix, A.; Neumann, B.; Stammler,
H.-G.; Mitzel, N. W. ChemistryOpen 2019, 8, 304. (c) Lamm, J.-
H.; Niermeier, P.; Körte, L. A.; Neumann, B.; Stammler, H.-G.;
Mitzel, N. W. Synthesis 2018, 50, 2009.
(14) Wang, T.; Wang, D.-H. Org. Lett. 2019, 21, 3981.
(15) Schwabedissen, J.; Trapp, P. C.; Stammler, H.-G.; Neumann, B.;
Lamm, J.-H.; Vishnevskiy, Y. V.; Körte, L. A.; Mitzel, N. W. Chem.
Eur. J. 2019, 25, 7339.
(8) Hunter, C. A. Chem. Soc. Rev. 1994, 23, 101.
(9) Coates, G. W.; Dunn, A. R.; Henling, L. M.; Dougherty, D. A.;
Grubbs, R. H. Angew. Chem., Int. Ed. Engl. 1997, 36, 248; Angew.
Chem. 1997, 109, 290.
(10) Blomeyer, S.; Linnemannstöns, M.; Nissen, J. H.; Paulus, J.;
Neumann, B.; Stammler, H.-G.; Mitzel, N. W. Angew. Chem. Int.
Ed. 2017, 56, 13259; Angew. Chem. 2017, 129, 13443.
(16) Hoge, B.; Bader, J. J. Fluorine Chem. 2007, 128, 857.
© 2020. Thieme. All rights reserved. Synthesis 2020, 52, A–J