Fluoride complexation by bidentate silicon Lewis acids

Article abstract of DOI:10.1039/c6dt04608h

Diethynyldiphenylsilane (1) and divinyldiphenylsilane (2) were functionalized by hydrosilylation reactions with HSiMe₂Cl, HSiMeCl₂ and HSiCl₃. Fluorination of the resulting compounds generates bidentate open-chain Lewis ac

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Fluoride complexation by bidentate silicon Lewis
acids†
Cite this: DOI: 10.1039/c6dt04608h
Jan Horstmann, Mark Niemann, Katarína Berthold, Andreas Mix, Beate Neumann,
Hans-Georg Stammler and Norbert W. Mitzel*
Diethynyldiphenylsilane (1) and divinyldiphenylsilane (2) were functionalized by hydrosilylation reactions
with HSiMe2Cl, HSiMeCl2 and HSiCl3. Fluorination of the resulting compounds generates bidentate open-
chain Lewis acids of increasing acidity. All semi-flexible [Ph2Si(CHvCHSiFnMe3−n 2
) (n = 1, 2, 3)] and
flexible [Ph2Si(CH2–CH2SiFnMe3−n 2 (n = 1, 2, 3)] bidentate Lewis acids were obtained in good to excellent
)
Received 6th December 2016,
Accepted 11th January 2017
yields. The different fluoride ion complexation behavior was explored in detail by multinuclear (low temp-
erature) NMR spectroscopy. The Lewis acidic bidentate molecules as well as the resulting mono- and bis-
silicates were completely characterized by NMR spectroscopy, mass spectrometry and in part by elemen-
tal analysis and X-ray diffraction experiments.
DOI: 10.1039/c6dt04608h
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tin-containing ferrocenophanes of Jurkschat et al.9 Most of the
Introduction
bidentate group 14 based Lewis acids have 1,2-benzene7,10,11 or
Self-organization and alignment of small molecular guests 1,8-naphtalene11,12 backbones, which sterically force anions
with large molecular hosts is an important field of supramole- between the acidic functions under formation of five- or six-
cular chemistry and termed host–guest chemistry. On the membered rings. Most recently, Jurkschat and co-workers have
basis of Lewis acid–base-adduct formation there are two kinds reported the synthesis of bifunctional Lewis acids containing
of host–guest chemistry. One is a Lewis basic host coordinat- silicon and tin atoms and their complexation behavior towards
ing a Lewis acidic guest, the other inverse system is a Lewis halide anions.14 These open-chain compounds exhibit two
acidic host interacting with a Lewis basic guest.
Lewis acidic tin atoms flexibly connected to a silicon atom by
Typical Lewis basic hosts are known since Pedersen reported methylene groups enabling to capture halide anions between
the synthesis of crown ethers in 1967,1 but in principle every the tin atoms. To our knowledge there are no reports on Lewis
multidentate ligand coordinating a metal cation can be regarded acidic silicon atoms integrated into a flexible open-chain motif
as Lewis basic host system. The reverse situation, Lewis acidic or any investigations of their behavior towards different host
hosts containing multiple Lewis acidic atoms, are known as guest stoichiometries, i.e. more than one equivalent of halide
poly-Lewis acids.2 They are capable of complexing anions as anions. During our investigations in the field of poly-Lewis acids
guest species.3 Many Lewis acidic fluoride receptors based on with rigid organic frameworks,2,15,16 we became interested in
boron, mercury, tellurium and antimony were reported by poly-Lewis acids with higher flexibility17 and their behavior and
Gabbaï and coworkers over the last twenty years.4 Group 14 selectivity towards halide anion complexation phenomena.
elements have also been used to construct silicon-, germanium-
Herein we report efficient syntheses of bidentate fluorosilanes
and tin-based neutral anion receptors in cyclic or open-chain with flexible (ethylene) and more rigid (vinylene) side arms by
systems.2a,3,5–13 Prominent examples for group 14 based recep- hydrosilylation of divinyldiphenylsilane and diethynyldiphenyl-
tors are the fluorinated trisilacyclohexane derivatives of silane and subsequent fluorination reactions. The bidentate
Brondani et al.,5 a 12-silacrown-3 reported by Jung and Xia,6 the Lewis acidic hosts were converted with one or two equivalents of
ortho-bis(fluorosilyl)benzenes of Ito et al.,7 1,8-digermacyclo- fluoride ions as guests using potassium fluoride and 18-crown-6
tetradecane derivatives reported by Takeuchi et al.8 and several or [2.2.2]cryptand. We studied the behavior towards fluoride ions
by NMR spectroscopy and X-ray diffraction.
Bielefeld University, Faculty of Chemistry, Chair of Inorganic and Structural
Chemistry, Centre for Molecular Materials CM2, Universitätsstraße 25,
Results and discussion
33615 Bielefeld, Germany. E-mail: mitzel@uni-bielefeld.de
†Electronic supplementary information (ESI) available. CCDC 1520262–1520270.
The organic frameworks diethynyldiphenylsilane (1) and
divinyldiphenylsilane (2) were used to generate bidentate poly-
For ESI and crystallographic data in CIF or other electronic format see DOI:
10.1039/c6dt04608h
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ation reaction (Scheme 1). Three doublets of doublets in the
1H NMR spectrum with three different coupling constants of
3
2
3JH,H = 20.3 Hz, JH,H = 14.6 Hz and JH,H = 3.7 Hz are charac-
terristic for the terminal vinyl substituents of silane 2.18
Hydrosilylation reactions
The unsaturated silanes 1 and 2 were converted into terminally
silylated species with SiClMe2, SiCl2Me and SiCl3 groups in
hydrosilylation reactions (Scheme 2).2,15a,17
Scheme 1 Syntheses of 1 and 2 via salt elimination reactions. Reagents
and conditions: (i) (a) HCuCMgBr, THF, 0 °C – reflux, 12 h, 91%; (b)
acetylene, n-BuLi, THF, −30 °C – rt., 8 h, 70%; (ii) CH2vCHMgCl, THF,
0 °C – reflux, 12 h, 92%.
All products were obtained in nearly quantitative yields
(>97%) and characterized by multinuclear NMR spectroscopy.
The less flexible (unsaturated) chlorosilanes 3, 4 and 5 were
isolated as colorless solids while all flexible (saturated) chloro-
silanes 6, 7 and 8 are colorless highly viscous liquids. Selected
1H and 29Si NMR chemical shifts of the unsaturated chloro-
silanes 3, 4 and 5 in CDCl3 at ambient temperature are listed
in Table 1. In all three cases, the CvC double bond is selec-
tively trans-substituted as it is indicated by the high coupling
constant of the vinylic proton resonances (∼22 Hz). The hydro-
silylation reactions of 2 must be carried out in Et2O to avoid
the formation of the Markovnikov product.
Lewis acids.18 Silane 1 was prepared by salt elimination reac-
tion of dichlorodiphenylsilane with the commercially available
ethynylmagnesium bromide (Scheme 1).19
Compound 1 was purified by short-path distillation, com-
pound 2 by distillation. 1 crystallized in pure form. Their iden-
tity was confirmed by NMR spectroscopy, mass spectrometry
and – in the case of 1 – by X-ray diffraction experiments. The
crystal belongs to the monoclinic system, space group P21/c,
with four molecules per unit cell (Fig. 1).
The 13C{1H} NMR spectra show the anticipated number of
resonances. In all cases, the resonance of the olefinic carbon
atom connected to the central silicon atom [δ = 152.1 (3),
150.2 (4) and 152.7 ppm (5)] is remarkably downfield shifted
compared to the adjacent carbon atom [δ = 147.3 (3), 148.2 (4)
and 145.1 ppm (5)].
The coordination geometry at the silicon atom is almost
tetrahedral [angles from 105.6(1)°, C(3)–Si(1)–C(5), to 114.2(1)°
C(11)–Si(1)–C(5)]. The distances Si(1)–C(11) and Si(1)–C(5) are
in a normal range for Si–C bonds, the distances Si(1)–C(1) and
Si(1)–C(3) (1.825(1) and 1.837(1) Å) are both longer than the
sum of the covalent radii of Si and C atoms.20 The bonds C(1)–
C(2) and C(3)–C(4) (1.192(2) and 1.196(2) Å) are of typical
length for terminal CuC triple bonds.21
1
Selected H and 29Si NMR chemical shifts of the saturated
chlorosilanes 6, 7 and 8 in CDCl3 at ambient temperature are
listed in Table 2. The gap in chemical shift between the multi-
plets of the methylene groups in the 1H NMR spectra
decreases with increasing the Lewis acidity of the chlorosilyl
group from 6 to 8. Surprisingly, 8 only shows a broadened
singlet for both methylene groups.
Divinyldiphenylsilane (2) was prepared by reacting dichloro-
diphenylsilane with vinylmagnesium chloride in a salt elimin-
The EI mass spectra of all saturated species do hardly show
a molecular ion peak. All fragmentation patterns indicate the
Fig. 1 Molecular structure of diethynyldiphenylsilane (1) in the crystal-
line state. Displacement ellipsoids are drawn at 50% probability level.
Phenyl hydrogen atoms are omitted for clarity. Selected bond lengths
[Å] and angles [°]: Si(1)–C(1) 1.825(1), Si(1)–C(3) 1.837(1), Si(1)–C(5) 1.864(1),
Si(1)–C(11) 1.852(1), C(1)–C(2) 1.192(2), C(3)–C(4) 1.196(2);C(1)–Si(1)–
C(3) 108.9(1), C(1)–Si(1)–C(5) 108.3(1), C(1)–Si(1)–C(11) 110.7(1), C(3)–Si(1)–
C(5) 105.6(1), C(3)–Si(1)–C(11) 108.9(1), C(11)–Si(1)–C(5) 114.2(1),
C(2)–C(1)–Si(1) 177.5(1), C(4)–C(3)–Si(1) 175.0(1).
Scheme 2 Syntheses of 3–8 via hydrosilylation of 1 and 2. Reagents
and conditions: (i) HSiClnMe(3−n), Karstedt’s catalyst, rt., 2 h, 97–99% (ii)
1.5–2 eq. HSiClnMe(3−n), Et2O, Karstedt’s catalyst, rt., 24 h, 96–99%.
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Table 1 Selected NMR chemical shifts [ppm] of compounds 3, 4 and 5 in CDCl3 (298 K)
Compound
n
SiClnMe(3−n)
Ph2Si
Ph2SiCHv
vCHSiClnMe(3−n)
3 (SiClMe2)
4 (SiCl2Me)
5 (SiCl3)
1
2
3
16.7
14.1
−6.1
−24.7
−21.1
−20.6
7.12
7.33
7.49
6.72
6.69
6.65
Table 2 Selected NMR chemical shifts [ppm] of compounds 6, 7 and 8 in CDCl3 (298 K)
Compound
n
SiClnMe(3−n)
Ph2Si
Ph2SiCH2
CH2SiClnMe(3−n)
6 (SiClMe2)
7 (SiCl2Me)
8 (SiCl3)
1
2
3
33.0
33.3
12.9
−3.6
−3.6
−3.4
1.12
1.23
1.29
0.74
1.02
1.29
cleavage of one of the two side arms. Owing to silicon carbide as observed in other hydrosilylated products.2,22 Both CvC−Si
formation elemental analyses of these compounds gave mis- angles [C(2)–C(1)–Si(1) 125.1(3)° and C(1)–C(2)–Si(2) 123.3(3)°]
leading results.
are wide. The torsion angle Si(1)–C(1)–C(2)–Si(2) [171.3(2)°] is
Single crystals suitable for X-ray diffraction experiments of slightly smaller than the expected 180°. Si(2) is tetrahedrally
3 (see ESI, Fig. S1†) and 5 were obtained by slow evaporation coordinated. Deviations from ideal tetrahedral angle are as
of concentrated dichloromethane solutions. Due to similarity predicted by the VSEPR model: smaller for the Cl–Si–Cl angles
of the molecular geometry, only chlorosilane 5 is presented in and wider for the C–Si–Cl angles.23,24
Fig. 2.
Bis(trichlorosilylvinyl)diphenylsilane (5) crystallizes in the
monoclinic space group C2/c, with four molecules in the unit
cell. The molecule is located on a two-fold axis. The CvC
To increase the Lewis acidity, the bidentate molecules 3–8
double bond C(1)–C(2) [1.330(5) Å] is of nearly the same length
Fluorination reactions
were converted into fluorosilanes by applying an excess of anti-
mony trifluoride.25 In the course of these reactions we fre-
quently faced the occurrence of antimony trichloride contents
in our products which were difficult to identify by the usual
spectroscopic methods. We assume the formation of SbCl3-
arene complexes to be the case.26 Remaining traces of anti-
mony trichloride (less than 10% of the isolated yields) were
removed by sublimation (10−2 mbar, 40 °C) and the absence of
SbCl3 was proven by the Carr–Price test.27 The fluorosilanes 9,
10, 12 and 13 were obtained nearly quantitatively as colorless
highly viscous oils. Trifluoro compounds 11 and 14 were iso-
lated by sublimation (10−2 mbar, 80 °C) as colorless crystals in
yields slightly below 90% (Scheme 3).
Selected 1H, 19F and 29Si NMR chemical shifts and coupling
constants of the unsaturated fluorosilanes 9, 10 and 11 in
CDCl3 at ambient temperature are listed in Table 3. The multi-
plicities of the vinylic proton signals in the 1H NMR spectra
[9 (dd), 10 (dt) and 11 (dq)] are characteristic for the substitution
pattern at the terminal silicon atoms. The vinylic coupling
(∼23 Hz) in 9–11 again proves the trans-substitution pattern at
the CvC double bonds. Along the series of compounds 9 to
Fig. 2 Molecular structure of 5 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. Hydrogen atoms of the
11, i.e. upon increasing the number of fluorine atoms, the 29Si
NMR chemical shifts of the fluorosilyl groups are shifted to
phenyl substituents are omitted for clarity. Selected bond lengths [Å]
and angles [°]: Cl(1)–Si(2) 2.039(2), Cl(2)–Si(2) 2.009(2), Cl(3)–Si(2) higher field. The 19F resonances are split due to coupling to
2.023(2), Si(1)–C(1) 1.864(4), Si(1)–C(3) 1.872(4), Si(2)–C(2) 1.821(4),
C(1)–C(2) 1.330(5); C(1)–Si(1)–C(1’) 110.1(3), C(3)–Si(1)–C(1) 107.2(2),
C(3)–Si(1)–C(3’) 110.1(2), C(2)–C(1)–Si(1) 125.1(3), C(1)–C(2)–Si(2) 123.3(3),
C(2)–Si(2)–Cl(1) 110.7(1), Cl(1)–Si(2)–Cl(2) 108.0(1), Cl(1)–Si(2)–Cl(3)
the methyl and vinyl protons adjacent to the fluorosilyl group;
this results in a doublet of septets for 9, a doublet of quartets
for 10 and a doublet for 11, respectively. Single crystals suit-
able for X-ray diffraction of 11 were obtained by slow evapor-
ation of a concentrated solution in diethyl ether (Fig. 3).
107.8(1), Cl(2)–Si(2)–Cl(3) 107.2(1). Symmetry equivalent atoms are
generated by the operation 1 − x, y, 1/2 − z.
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Fig. 3 Molecular structure of 11 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. For clarity, minor occupied
disordered atoms and hydrogen atoms of the phenyl substituents are
omitted. Selected bond lengths [Å] and angles [°]: Si(1)–C(1) 1.877(2),
Si(1)–C(3) 1.875(2), Si(1)–C(5) 1.868(2), C(1)–C(2) 1.326(3), C(3)–C(4)
1.337(3), C(2)–Si(2) 1.820(2), Si(2)–F(1) 1.544(3), Si(2)–F(2) 1.602(2), Si(2)–
F(3) 1.548(2); C(3)–Si(1)–C(1) 107.6(1), C(5)–Si(1)–C(1) 109.1(1), C(5)–
Si(1)–C(3) 110.8(1), C(11)–Si(1)–C(1) 107.3(1), C(2)–C(1)–Si(1) 125.3(1),
C(1)–C(2)–Si(2) 122.9(1), F(1)–Si(2)–C(2) 111.1(1), F(1)–Si(2)–F(3) 111.0(2),
F(1)–Si(2)–F(2) 106.5(2), F(2)–Si(2)–F(3) 103.0(2).
Scheme 3 Syntheses of 9–14 via chlorinated species 3–8. Reagents
and conditions: (i) SbF3, pentane, rt., 20 h, 86–100%.
Bis(trifluorosilylvinyl)diphenylsilane (11) crystallizes in the
monoclinic space group P21/c, with four molecules per unit
cell. Both trifluorosilyl groups are disordered at two positions.
The CvC double bonds C(1)–C(2) and C(3)–C(4) exhibit equal
lengths within experimental error and both are shorter than
typical silyl-substituted CvC double bonds.28 The electron-
withdrawing effect of the trifluorosilyl group leads to short
bonds for C(2)–Si(2) [1.820(2) Å] and C(4)–Si(3) [1.824 (3) Å].
The olefinic angles are widened [from C(3)–C(4)–Si(3) 121.6(2)°
to Si(1)–C(1)–C(2) 125.3(2)°] and the coordination spheres
about the CvC double bonds deviate slightly from planarity
as is indicated by the torsion angles Si(1)–C(1)–C(2)–Si(2) at
172.8(1)° and Si(1)–C(3)–C(4)–Si(3) at 177.4(1)°.
entails higher order which could not be better resolved, even
1
at 470 MHz. The JSi,F coupling constants – extracted from the
29Si NMR spectra – confirm the assumed coupling patterns [12
280.1 Hz (d), 13 299.0 Hz (t) and 14 286.0 (q)]. Single crystals
suitable for X-ray diffraction of 14 were obtained by sublima-
tion (10−2 mbar, 80 °C) (Fig. 4).
Bis(trifluorosilylethyl)diphenylsilane (14) crystallizes in the
monoclinic space group P21/n, with four molecules per unit
cell. The angle between the two side arms at the central silicon
atom is widened to 112.1(1)° [C(3)–Si(1)–C(1)]. As expected the
Si–C single bonds between the methylene carbon atoms and
the silicon atoms are shorter at the Lewis acidic fluorosilyl
groups [C(2)–Si(2) 1.827(2) and C(4)–Si(3) 1.816(2) Å] than
towards the central silicon atom [Si(1)–C(1) 1.876(2) and Si(1)–
C(3) 1.876(2) Å]. The C–C single bonds fall within the normal
range for ethylene bridges between silyl groups [C(1)–C(2)
1.548(2) and C(3)–C(4) 1.551(2) Å].29 All Si–F bond lengths are
in a range from 1.555(2) Å [Si(3)–F(6)] to 1.577(1) Å [Si(2)–F(1)],
the F–Si–F angles are all smaller than the typical tetrahedral
angle [from F(6)–Si(3)–F(4) 105.0(1)° to F(2)–Si(2)–F(3)
106.8(1)°].
EI mass spectroscopy of the flexible bidentate molecules 12,
13 and 14 resulted in the same fragmentation of one side arm
as was observed for the corresponding chlorosilanes; mole-
cular ions could therefore not be detected. Elemental analyses
failed to give reliable results owing to the high fluorine and
1
silicon content. Selected H, 19F and 29Si NMR chemical shifts
of the saturated fluorosilanes 12, 13 and 14 in CDCl3 are listed
in Table 4.
The 19F NMR spectra reveal diagnostic patterns for the
coupling between the methylene protons and the fluorine
atoms at the adjacent fluorosilyl group. This results in a triplet
for 14. The coupling with the methyl groups of 12 and 13
Table 3 Selected NMR shifts [ppm] and coupling constants [Hz] of compounds 9, 10 and 11 in CDCl3 (298 K)
Compound
n
SiFnMe(3−n)
vCHSiFnMe(3−n)
3JH,H; 3JF,H
SiFnMe(3−n)
9 (SiFMe2)
10 (SiF2Me)
11 (SiF3)
1
2
3
17.7
−16.1
−78.1
6.71 (dd)
6.54 (dt)
6.39 (dq)
22.8; 2.8
23.0; 2.4
23.1; 3.4
−162.1
−137.1
−141.5
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Table 4 Selected NMR shifts [ppm] of compounds 12, 13, and 14 in CDCl3 (298 K)
Compound
n
SiFnMe(3−n)
Ph2SiCH2
CH2SiFnMe(3−n)
SiFnMe(3−n)
12 (SiFMe2)
13 (SiF2Me)
14 (SiF3)
1
2
3
33.1
2.4
−59.8
1.13
1.14
1.23
0.65
0.69
0.88
−163.0
−137.5
−139.6
towards [K·18-crown-6]+F−. The bidentate compounds 10 and
13 with difluoromethylsilyl groups result in an uninterpretable
product mixture in the 1H NMR and 19F NMR spectra, only the
most Lewis acidic trifluorosilyl compounds 11 and 14 forms
one complexation product as exemplarily shown for the un-
saturated trifluorosilyl bidentate molecule 11 (Fig. 5).
An equimolar amount of [K·18-crown-6]+F− was added to 11
1
and the reaction was followed by H, 19F and 29Si NMR spec-
1
troscopy. Compared to the spectrum of 11, the H NMR spec-
trum of product 15 (1 eq. [K·18-crown-6]+F− added) displays a
slight downfield shift and disappearance of the multiplicity
for the resonance (6.48 ppm) of the CH group adjacent to the
silicate unit. The fact that both side arms are chemically equi-
valent on the NMR timescale and that all olefinic proton
signals of product 15 are broadened and shifted [δ (1H) = 7.67
to 7.57 ppm and 6.39 to 6.48 ppm], indicates rapid exchange
of fluoride ions and involvement of both trifluorosilyl groups
in fluoride binding.
Fig. 4 Molecular structure of 14 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. Hydrogen atoms of the
phenyl substituents are omitted for clarity. Selected bond lengths [Å]
and angles [°]: Si(1)–C(1) 1.876(2), Si(1)–C(3) 1.876(2), Si(1)–C(5) 1.877(2),
Si(1)–C(11) 1.880(2), C(1)–C(2) 1.548(2), C(3)–C(4) 1.551(2), C(2)–Si(2)
1.827(2), C(4)–Si(3) 1.816(2), Si(2)–F(1) 1.577(2), Si(2)–F(2) 1.570(1), Si(2)–
F(3) 1.570(1); C(3)–Si(1)–C(1) 112.1(1), C(5)–Si(1)–C(1) 107.8(1), C(5)–
Si(1)–C(3) 111.5(1), C(11)–Si(1)–C(1) 109.5(1), C(2)–C(1)–Si(1) 114.1(1),
C(1)–C(2)–Si(2) 112.2(1), F(1)–Si(2)–C(2) 111.5(1), F(1)–Si(2)–F(3) 105.2(1),
F(1)–Si(2)–F(2) 105.5(1), F(2)–Si(2)–F(3) 106.8(1).
Addition of a second equivalent of [K·18-crown-6]+F− leads
to formation of the bissilicate 16. The even broader lines of
the olefinic protons (Fig. 5) for 16 (compared to 15 and 11)
indicate an accelerated fluoride exchange (it cannot be distin-
guished, whether it is intra- or intermolecular or a positional
exchange within one SiF4 group by pseudorotation). Even the
hydrogen atoms of the phenyl groups are influenced by the for-
mation of monosilicate 15 and bisilicate 16. Selected 1H, 19F
and 29Si NMR chemical shifts of the unsaturated compounds
11, 15 and 16 are listed in Table 5.
Fluoride complexation supported by 18-crown-6
The behavior of the bidentate Lewis acids 9–14 towards fluor-
ide ions was analyzed in complexation reactions on NMR tube
scale.10,14 Primarily, we tested the conditions described by
Pietschnig using potassium fluoride in acetone.30
Interestingly, we did not observe a reaction with our most
Lewis acidic compounds 11 or 14. Even after refluxing for
several days, no changes, neither in the 1H nor in the 19F NMR
spectra, were detected. To minimize the interaction between
potassium and fluoride ions as well as to increase the reactivity
and solubility we added 18-crown-6.1,31 Despite many reports
on benzene, toluene or THF32 as suitable solvents for this reac-
tion, in our hands [K·18-crown-6]+F− could only be generated
using
dichloromethane
and
spray-dried
potassium
fluoride.7,28a,31c,33
First we attempted the reaction of 9–14 with two equiva-
lents of isolated [K·18-crown-6]+F− in chloroform-d1 to estab-
lish a ratio of 1 : 1 of fluoride ions and Lewis-acidic silyl
groups. The less Lewis-acidic bidentate molecules 9 and 12
Fig. 5 1H NMR (500 MHz) spectra of the Lewis-acidic bidentate mole-
cule 11 and its conversion with one (→15) and two equivalents (→16) of
bearing dimethylfluorosilyl groups showed no reaction [K·18-crown-6]+F− in chloroform-d1* at 298 K.
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solution (Fig. 6).5,7 At 178 K one observes two signals at −121
and −141 ppm, typical for tetra- and pentacoordinated silicon
species.34 This does not provide evidence for a bridging fluor-
ide ion between the two side arms, but rather for the simul-
taneous presence of SiF3 and SiF4 groups. The intensity ratio
of 4 : 3 underpins this interpretation.
Further proof stems from a structure determination in the
solid state. Single crystals suitable for X-ray diffraction experi-
ments of 15 were obtained by slow evaporation of a dichloro-
methane solution and show the presence of two differently co-
ordinated fluorosilyl groups (Fig. 7).
The potassium 18-crown-6 salt of silicate 15 crystallizes in
the monoclinic space group P21 with two molecules in the unit
cell. To our knowledge, this is the first structurally character-
ized potassium 18-crown-6 silicate polymer. The potassium
atom is located 0.642(2) Å towards the trigonal-bipyramidal co-
ordinated silicon atom above the mean plane defined by the
six oxygen atoms of the 18-crown-6 ligand, the K⋯O contacts
ranging from 2.814(3) Å to 2.937(3) Å. Four K⋯F contacts can
be obtained: three of them to fluorine atoms of the trigonal-
bipyramide, one short contact to the axial fluorine atom (F(1)
⋯K(1) 2.682(3) Å) and two longer ones to the equatorial fluo-
rine atoms [K(1)⋯F(2) 3.155(4) Å and K(1)⋯F(3) 3.128(3) Å].
The fourth potassium–fluorine contact is built to one fluorine
atom of the trifluorosilyl group, which is disordered in ratio
81 : 19. The major occupied position of the fluorine atom is
located 2.65(1) Å from K1. This contact assembles the poly-
meric structure by translation of the molecule along 101. All
Si(3)–F bonds are of equal length within experimental error
Table 5 Selected NMR shifts [ppm] of fluorosilane 11, monosilicate 15,
and bissilicate 16 in CDCl3 at 298 K (n.o. = not observed)
Compound
SiF
SiF
o-ArH
vCHSiF
−
11 (SiF3)
15 (monosilicate)
16 (bissilicate)
−78.1
n.o.
−129.6
−141.5 (d)
−124.0 (br)
−121.5 (br)
7.47
7.52
7.56
6.39 (dq)
6.48 (d)
6.62 (d)
1
Neither by 29Si nor by H,29Si HMBC NMR experiments the
29Si chemical shifts of monosilicate 15 were observable at
ambient temperature, except that of the central silicon atom (δ
= −21.4 ppm). After adding a second equivalent of F−, we
detected a signal at −129.6 ppm, a typical range for pentacoor-
dinated silicates.30,33,34 We conclude that a bissilicate 16 with
two anionic tetrafluorosilicate groups was formed. Its 19F NMR
spectrum shows a sharp singlet at −121.5 ppm for these
groups (Fig. 6). The chemical equivalence of all fluorine atoms
at ambient temperature on the NMR timescale implies rapidly
exchanging axial and equatorial fluorine atoms.
The 19F NMR spectrum of 15, the monosilicate, displays a
broad signal at −124.0 ppm, i.e. a chemical shift between the
−
signals of 11 (with two SiF3 groups) and 16 (with two SiF4
groups). This signifies
a fluoride ion exchange process
between SiF3- and SiF4 groups in 15. Consequently, we per-
formed low-temperature 19F NMR measurements on silicate 15
in order to determine the position of the added fluoride ion in
Fig. 7 Molecular structure of 15 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. Only vinyl hydrogen and
major occupied disordered atoms are shown for clarity. Selected bond
lengths [Å] and angles [°]: K(1)–F(1) 2.682(3), K(1)–F(2) 3.155(4), K(1)–F(3)
3.128(3), K(1)–F(7) 2.86(3), Si(2)–F(1) 1.695(3), Si(2)–F(2) 1.609(3), Si(2)–
F(3) 1.622(3), Si(2)–F(4) 1.663(3), Si(2)–C(2) 1.877(5), Si(3)–F(5) 1.48(3),
Si(3)–F(6) 1.41(3), Si(3)–F(7) 1.45(3), Si(3)–C(4) 1.828(5), C(1)–C(2)
1.343(7), C(3)–C(4) 1.324(7), Si(1)–C(1) 1.862(4), Si(1)–C(3) 1.879(5), Si(1)–
C(5) 1.860(5), Si(1)–C(11) 1.868(5); F(1)–K(1)–F(7) 169.0(8), Si(2)–F(1)–K(1)
103.6(1), Si(3)–F(7)–K(1) 149(2), F(1)–Si(2)–F(4) 177.2(2), F(1)–Si(2)–C(2)
90.1(2), F(1)–Si(2)–F(3) 88.0(2), F(1)–Si(2)–F(2) 88.1(2), C(2)–Si(2)–F(3)
123.6(2), C(2)–Si(2)–F(2) 123.9(2), F(2)–Si(2)–F(3) 112.3(2), C(4)–Si(3)–
F(7) 111.0(1), F(5)–Si(3)–F(7) 108.6(2), C(1)–Si(1)–C(3) 107.8(2). Symmetry
equivalent atoms are generated by the operations −1 + x, y, 1 + z and
1 + x, y, 1 + z.
Fig. 6 19F NMR spectra of 11, 15 (1 eq. [K·18-crown-6]+F− added) and
16 (2 eq. [K·18-crown-6]+F− added) at various temperatures in dichloro-
methane-d2 (564 MHz); # denotes impurity (ca. 1% at rt.).
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and shorter than the Si–F bond in 11. As expected for trigonal- gives rise to the assumption that the higher flexibility of 14
bipyramidally coordinated silicates, the Si–F(ax) bonds are takes no influence towards the complexation of fluoride ions.
found to be remarkably longer than the Si–F(eq) bonds [e.g. Results of the low-temperature NMR measurements and the
Si(2)–F(1) 1.695(3) Å vs. Si(2)–F(2) 1.609(3) Å].35 The axial fluorine crystal structure show the formation of the corresponding pot-
atoms are nearly in plane with the CvC double bond C(1)– assium 18-crown-6 coordination polymer with a monosilicate
C(2) as is indicated by the torsion angles C(1)−C(2)−Si(2)−F(4) anion, compound 17 (see ESI, Fig. S3†). Further addition of
[6.2(5)°] and C(1)−C(2)−Si(2)−F(1) [173.3(4)°] and the hydro- potassium fluoride and 18-crown-6 leads to the formation of a
gen fluorine contacts H(1)⋯F(4) (2.330(3) Å) and H(2)⋯F(1) bissilicate analogous to 16.
(2.468(3) Å). The angles at the pentacoordinated silicon center
are slightly distorted towards the potassium atom as indicated
Fluoride complexation supported by [2.2.2]cryptand
by the angles F(1)–Si(2)–F(3) 88.0(2)°, F(1)–Si(2)–F(2) 88.1(2)°
and F(2)–Si(2)–F(3) 112.3(2)°.31c The crystal structure of 15 is
In order to further decrease the observed interactions between
potassium and fluoride ions [2.2.2]cryptand was used as a
complexing agent for potassium.37 Preparative access to
{K·[2.2.2]cryptand}+F− could be realized by using spray-dried
potassium fluoride and [2.2.2]cryptand in acetone. This was
necessary, as an attempt to prepare the salt in dichloro-
methane led to formation of the chloride salt {K·[2.2.2]
cryptand}+Cl−, indicating the substitution of chloride in
CH2Cl2 by this activated form of potassium fluoride.38
Consequently, we had to use acetone as a solvent for the low-
temperature investigations of fluoride complexation under
with {K·[2.2.2]cryptand}+F−.
in a good agreement with our low temperature NMR studies in
solution. Two differrently coordinated silicon atoms are
formed: one tetracoordinated silicon and one pentacoordi-
nated silicate.
Due to the fact that we observed only one 19F NMR singlet
for bissilicate 16, although the axial and equatorial fluorine
atoms of a pentacoordinated silicon species are not chemically
equivalent,7,30,36 low-temperature NMR investigations were per-
formed. Even at 195 K no signal-splitting in the 19F NMR spec-
trum into F(ax) and F(eq) resonances was observed (likely due to
pseudorotation of the SiF4 group). In 1H,29Si HMBC experi-
ments of 16 a quintet-like signal at −130 ppm (1JSi,F = 205 Hz)
can be observed at 203 K, confirming the formation of a biste-
trafluorosilicate (Scheme 4).
The conversion of one and two equivalents of the {K·[2.2.2]
cryptand}+F− salt with the rigid and flexible fluorophilic biden-
tate molecules 11 and 14 led to the formation of monosilicates
19 and 21 as well as the corresponding bissilicates 20 and 22.
Selected 1H, 19F and 29Si NMR chemical shifts of the rigid
bidentate molecules (19, 20) and the more flexible ones (21,
22) in acetone-d6 at ambient temperature are listed in Table 6.
Comparable results to those described above are found for
the conversion of the saturated bidentate compound 14 with
one equivalent of [K·18-crown-6]+F− (see ESI† for details). This
1
In contrast to the starting materials 11 and 14 the H NMR
3
spectra of monosilicates 19 and 21 show no JF,H coupling to
the hydrogen atoms adjacent to the fluorosilyl group. This
indicates rapid exchange of the fluoride ion between both
Lewis acidic sites in solution. No 29Si NMR resonances for 19
or 21 were observable at ambient temperature, except for the
doubly phenyl substituted Si atoms. The 19F NMR spectra of
both monosilicates 19 and 21 show broad signals at ambient
temperature (−123.6 and −120.1 ppm, respectively). In order
to analyze the complexation in solution, 19F NMR spectra at
various temperatures were recorded for the conversion reac-
tions of 11 with one or two equivalents of {K·[2.2.2]
cryptand}+F− (Fig. 8).
The 19F NMR spectrum of 11 displays a doublet at
−141.5 ppm (3JF,H = 3.4 Hz). After conversion with two equiva-
lents of {K·[2.2.2]cryptand}+F− a sharp singlet of bissilicate 20
Table 6 Selected NMR shifts [ppm] of the vinylic silicates 19 and 20
(x = 1) and the saturated silicates 21 and 22 (x = 2) in acetone-d6 at
298 K (n.o. = not abservable)
Compound
SiF
SiF
CHxSiF
Scheme 4 Syntheses of the monosilicates 15 and 16 and the bissili-
cates 17 and 18, respectively. Reagents and conditions: (i) 1 eq. [K·18-
crown-6]+F−, CH2Cl2, rt., 2–3 h, quant. (ii) 2 eq. [K·18-crown-6]+F−,
CH2Cl2, rt., 2–4 h, quant.
19 (monosilicate)
20 (bissilicate)
21 (monosilicate)
22 (bissilicate)
n.o.
−130.2
n.o.
−120.1
−119.8
−123.6
−117.3
6.62
6.68
0.75
0.65
−113.6
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Fig. 8 19F NMR spectra (564 MHz) of trifluorosilyl compound 11, silicate
19 (1 eq. {K·[2.2.2]cryptand}+F−) and bissilicate 20 (2 eq. {K·[2.2.2]
cryptand}+F−) at various temperatures in acetone-d6 solution.
Fig. 9 19F NMR spectra (564 MHz) of trifluorosilyl compound 14, sili-
cate 21 (1 eq. {K·[2.2.2]cryptand}+F−) and bissilicate 22 (2 eq. {K·[2.2.2]
cryptand}+F−) at various temperatures in acetone-d6 solution.
was detected at −119.8 ppm. Addition of just one equivalent of
{K·[2.2.2]cryptand}+F− results in the formation of the corres-
ions between the two terminal Lewis acidic groups.
ponding monosilicate 19. For this and at ambient temperature, Subsequent lowering the temperature leads to a downfield
the 19F NMR spectrum displays a broad signal at −120.1 ppm,
shift of the broad signal from −123.6 ppm to −116.4 ppm and
a shift value close to that of bissilicate 20. There occurs,
already at ambient temperature, a clear separation of the res- to the monosilicate 19, a separation of the tetra- and penta-
an increasing of the SiF3 group signal at −138 ppm. Analogous
onances of the SiF3 (−138 ppm) and SiF4 groups (−120 ppm).
coordinated silicon resonances is observed at low tempera-
Subsequent lowering the temperature leads to a slight down-
tures. In contrast to the 18-crown-6 monosilicates 15 and 17 as
field shift of the SiF4 signal (from −120.1 to −118.5 ppm) and well as the [2.2.2]cryptand monosilicate 19, 21 displays a
an increasing intensity of the sharp SiF3 singlet. The broaden-
broader signal for the SiF4 group at low temperature. The
ing of the SiF4 signal might be explicable by the slower
present data do not allow distinguishing the several possible
exchange of axial and equatorial fluorine atoms (pseudo dynamic processes including intra- and intermolecular fluor-
rotation in the silicon coordination sphere) also at low temp-
erature. 19F NMR spectra at various temperatures of the flexible
ide exchange, pseudorotation in the silicon coordination
sphere and assistance of the potassium ion in these processes.
Lewis acidic bidentate molecule 14 were also recorded for the Lower temperatures would be necessary for a better resolution,
conversion with one (formation of 21) or two equivalents (for-
mation of 22) of the fluoride salt (Fig. 9).
but the melting point of acetone sets a limit to such
measurements.
The 19F NMR spectra of 14 and 22 display sharp signals for
The 19F NMR spectra at 298 K of bissilicates 20 and 22
show sharp singlets at −119.8 (20) and −117.3 (22) ppm indi-
cating the presence of two chemically equivalent side arms
the two chemically identical SiF3 groups (−139.6 ppm, t, 3JF,H
=
2.8 Hz) and SiF4 groups (−117.3 ppm, s). The complexation of
just one equivalent {K·[2.2.2]cryptand}+F− results in the for- with rapid exchange of all axial and equatorial fluorine atoms
due to pseudo rotation. The 29Si NMR spectra of bissilicates 20
mation of 21. In contrast to the less flexible 19, monosilcate 21
shows a broad signal at −123.6 ppm in the 19F NMR spectrum
and 22 (determined by 1H, 29Si HMBC experiments) display
at ambient temperature, which reflects exchange of fluoride signals at −113.6 and −130.2 ppm, respectively, a typical range
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for pentacoordinated silicon atoms.5,7 The solid state struc-
tures of 20 and 22 are compatible with the NMR data of the
corresponding compounds. These molecular structures are the
first structurally characterized bissilicates with two [2.2.2]cryp-
tands bearing potassium cations (Fig. 10 and 11).
Potassium [2.2.2]cryptand bissilicate 20 crystallizes in the
ˉ
triclinic space group P1 with two molecules per unit cell. The
vinylic angles are wider than in a typical trigonal-planar
coordination geometry [Si(2)–C(14)–C(13) 127.2(1)°, C(14)–
C(13)–Si(1) 126.7(1)°, Si(1)–C(15)–C(16) 124.4(2)°, C(15)–C(16)–
Si(3) 125.4(2)°]. The pentacoordinated silicon atom Si(2) has a
trigonal bipyramidal coordination geometry with longer axial
Si(2)–F(ax) bonds [1.673(1) and 1.693(1) Å] and shorter Si(2)–
F(eq) bonds [1.616(1) and 1.622(1) Å].35 The other pentacoordi-
nated geometry at Si(3) is more distorted; Si(3)–F(8) [1.734(2) Å]
is the longest Si–F bond although F(8) is in equatorial posi-
tion. The angles F(5)–Si(3)–F(8) [84.7(1)°] and F(8)–Si(3)–F(6)
[86.2(1)°] are both smaller than 90°.
Despite saturation of the vinylic group potassium [2.2.2]
cryptand bissilicate 22 is isostructural to 20. The tetrafluoro-
silyl group at Si(2) displays a typical pentacoordinated silicate
with longer axial bonds [Si(2)–F(1) 1.699(1) and Si(2)–F(3)
1.679(1) Å] and shorter equatorial ones [Si(2)–F(2) 1.621(1) and
Si(2)–F(4) 1.615(1) Å]. The other SiF4 group is deformed, the
equatorial bond Si(3)–F(8) [1.660(1) Å] is as long as the axial
bond Si(3)–F(5) [1.659(1) Å] due to an intermolecular H⋯F
contact. The angles between the fluorine atoms are hardly
influenced by this deformation [F(5)–Si(3)–F(6) 173.0(1)° and
Fig. 11 Molecular structure of 22 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. Solely methylene hydrogen
atoms of the bissilicates are shown for clarity. Selected bond lengths [Å]
and angles [°]: Si(2)–F(1) 1.699(1), Si(2)–F(2) 1.621(1), Si(2)–F(3) 1.679(1),
Si(2)–F(4) 1.615(1), Si(3)–F(5) 1.659(1), Si(3)–F(6) 1.706(1), Si(3)–F(7) 1.614
(1), Si(3)–F(8) 1.660(1), Si(2)–C(14) 1.885(2), Si(3)–C(16) 1.875(1), C(13)–
C(14) 1.539(2), C(15)–C(16) 1.538(2), Si(1)–C(13) 1.877(1), Si(1)–C(15)
1.872(1), Si(1)–C(1) 1.918(4), Si(1)–C(7) 1.881(1); F(1)–Si(2)–F(2) 88.7(1),
F(1)–Si(2)–F(4) 89.4(1), F(2)–Si(2)–F(4) 116.9 (1), F(1)–Si(2)–F(3) 176.9(1),
F(1)–Si(2)–C(14) 89.3(1), C(14)–Si(2)–F(3) 93.7(1), C(14)–Si(2)–F(2)
120.1(1), F(5)–Si(3)–F(7) 89.4(1), F(5)–Si(3)–F(8) 88.3(1), F(5)–Si(3)–F(6)
173.0(1), F(7)–Si(3)–F(8) 118.6(1), F(5)–Si(3)–C(16) 90.6(1), C(16)–Si(3)–
F(7) 123.6(1), C(16)–Si(3)–F(8) 117.8(1), C(1)–Si(1)–C(7) 108.5(1), C(13)–
Si(1)–C(15) 108.6(1), Si(1)–C(13)–C(14) 117.7(1), C(13)–C(14)–Si(2)
121.0(1), Si(1)–C(15)–C(16) 116.9(1), C(15)–C(16)–Si(3) 117.8(1).
Fig. 10 Molecular structure of 20 in the crystalline state. Displacement
ellipsoids are drawn at 50% probability level. Only vinylic hydrogen and
major occupied disordered atoms are shown for clarity. Selected bond
lengths [Å] and angles [°]: Si(2)–F(1) 1.693(1), Si(2)–F(2) 1.622(1), Si(2)–
F(3) 1.673(1), Si(2)–F(4) 1.616(1), Si(3)–F(5) 1.691(3), Si(3)–F(6) 1.658(2),
Si(3)–F(7) 1.496(2), Si(3)–F(8) 1.734(2), Si(2)–C(14) 1.889(2), Si(3)–C(16)
1.903(3), C(13)–C(14) 1.334(2), C(15)–C(16) 1.295(4), Si(1)–C(13) 1.860(1),
Si(1)–C(15) 1.892(3), Si(1)–C(1) 1.928(5), Si(1)–C(7) 1.876(1); F(1)–Si(2)–
F(2) 89.0(1), F(1)–Si(2)–F(4) 89.7(1), F(2)–Si(2)–F(4) 116.4(1), F(1)–Si(2)–
F(3) 178.1(1), F(1)–Si(2)–C(14) 89.2(1), C(14)–Si(2)–F(3) 92.5(1), C(14)–
Si(2)–F(2) 120.8(1), F(5)–Si(3)–F(7) 91.3(1), F(5)–Si(3)–F(8) 84.7(1), F(5)–
Si(3)–F(6) 170.9(1), F(7)–Si(3)–F(8) 118.1(2), F(5)–Si(3)–C(16) 103.2(1),
C(16)–Si(3)–F(7) 110.8(1), C(16)–Si(3)–F(8) 130.3(1), C(1)–Si(1)–C(7)
109.3(1), C(13)–Si(1)–C(15) 112.1(1), Si(1)–C(13)–C(14) 126.7(1), C(13)–C(14)–
Si(2) 127.2(1), Si(1)–C(15)–C(16) 124.4(2), C(15)–C(16)–Si(3) 125.4(2).
Scheme 5 Syntheses of monosilicates 19, 21 and bissilicates 20, 22.
Reagents and conditions: (i) 1 eq. {K·[2.2.2]cryptand}+F−, acetone, rt.,
30 min, quant. (ii) 2 eq. {K·[2.2.2]cryptand}+F−, acetone, rt., 30 min,
quant.
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F(7)–Si(3)–F(8) 118.6(1)°]. Both side arms are found to be an Autospec X magnetic sector mass spectrometer with EBE
almost in anti-conformation, as the corresponding Si(1)–C–C–Si geometry (Vacuum Generators, Manchester, UK) equipped
torsion angles are close to 180°. The C–Si(1)–C angles are at with a standard EI source. Samples were introduced by push
least 108.5° indicating a tetrahedral geometry at Si(1). Due to rod in aluminum crucibles. Ions were accelerated by 8 kV. The
the torsion angle C(13)–Si(1)–C(15)–C(16) [55.3(1)°] the two reactions were carried out by using freshly distilled and dry
silicate groups are not positioned at maximum distance to solvents from solvent stills (acetone was isopropanol-free and
each other.
dried over anhydrous 4A molecular sieves and then distilled).
Scheme 5 summarizes the reactions taking place, when the Potassium fluoride (spray dried quality), 18-crown-6 and
Lewis acidic bidentate molecules are converted with one or [2.2.2]cryptand were all dried in vacuum at about 200 °C
two equivalents of {K·[2.2.2]cryptand}+F−. Both reaction path- before use. Elemental analyses were performed with CHNS
ways have been elucidated by low temperature NMR studies elemental analyzer HEKAtech EURO EA (too low values for
and X-ray crystallographic structure determinations.
carbon are due to the known formation of silicon carbide and
potassium carbonate).
Conclusion
Synthetic procedures
Starting from diethynyldiphenylsilane (1) and divinyldiphenyl-
Diethynyldiphenylsilane (1). Ethynyl magnesium bromide
silane (2), six new (methyl)chlorosilanes (3–8) have been syn- solution (0.50 M in THF; 50 mL, 25 mmol) was diluted in dry
thesized by hydrosilylation reactions in excellent yields THF (30 mL). Freshly distilled diphenyl dichlorosilane
(>95%). These chlorosilanes were converted into the corres- (2.5 mL, 12 mmol) was added dropwise at 0 °C. After the pale
ponding fluorosilanes (9–14). These new bidentate molecules orange solution was stirred overnight at ambient temperature,
exhibit a variety of Lewis acidities and all bear two equivalent it was heated to reflux for 1 h. The reaction was quenched with
fluorosilyl groups. The latter are connected by two types of sat. aq. ammonium chloride solution (50 mL), and the phases
backbones with different flexibility.
were separated. All volatile compounds of the organic phase
Quantitative complexation of the fluoride guest ion towards were removed and the crude product was subjected to a short-
the corresponding mono- and bissilicates is observed by react- path distillation at 120 °C at 10−2 mbar. The substance is
ing the bis(trifluorosilyl) hosts 11 and 14 with one or two yielded in the pure state as colorless crystals. Yield: 2.52 g
1
equivalents of [K·18-crown-6]+F− or {K·[2.2.2]cryptand}+F−. (91%). H NMR (300 MHz, CDCl3): δ = 7.77 (m, 4H, o-H), 7.44
Low-temperature NMR and X-ray diffraction experiments indi- (m, 6H, m-/p-H), 2.75 (s, 2H, CuCH) ppm. 13C{1H} NMR
cate in all cases the occurrence of monosilicates and bissili- (75 MHz, CDCl3): δ = 134.9 (o-C), 131.4 (i-C), 130.8 (p-C), 128.4
cates in solution and in the solid state depending on the (m-C), 97.5 (CuCH), 83.5 (CuCH) ppm. 29Si{1H} NMR
amount of fluoride added.
(60 MHz, CDCl3): δ = −48.3 ppm. Elemental analysis calcd (%)
The complexation of one equivalent fluoride guest results for C16H12Si (Mr = 232.35): C 82.71, H 5.21; found: C 82.90,
in a fluoride ion exchange process between SiF3- and SiF4 H 5.64. EI-MS (70 eV): m/z [assignments] = 231.1, 206.1, 178.1,
groups for the monosilicates 15, 17, 19 and 21. For the solu- 155.0, 129.0, 103.0, 77.0. HRMS (EI, 70 eV): calculated for
tion phase low-temperature NMR spectroscopy does not C16H12Si+: 232.07028; measured: 232.06996; dev. [ppm]: 0.32,
provide evidence for a bridging fluoride ion between the two dev. [mmu]: 1.38.
side arms, but rather for the simultaneous presence of SiF3
and SiF4 groups. This is in line with the crystallographic tion (1.9 M in THF; 20 mL, 38 mmol) was diluted in dry THF
Divinyldiphenylsilane (2). Vinylmagnesium chloride solu-
−
results for the solid state: molecules 15 and 17 contain both, (60 mL). Freshly distilled diphenyldichlorosilane (3.2 mL,
−
SiF3 and SiF4 groups, and form potassium-bridged polymeric 15 mmol) was added dropwise at 0 °C. After the brown solu-
chains. Bissilicates 16, 18, 20 and 22 have been quantitatively tion was stirred overnight at ambient temperature, it was
obtained by complexation of two equivalents fluoride guest. heated to reflux for 1 h. The reaction was quenched with sat.
All SiF4 groups show a rapid pseudorotation in the silicon aq. ammonium chloride solution (40 mL), and the phases
coordination sphere between axial and equatorial fluorine were separated. All volatile compounds of the organic phase
atoms even at low temperature.
were removed under reduced pressure and the oily crude
product was distilled at 80 °C at 10−2 mbar to give a colorless
liquid. Yield: 3.26 g (92%). 1H NMR (500 MHz, CDCl3): δ =
7.56 (m, 4H, o-H), 7.40 (m, 6H, m-/p-H), 6.52 (dd, 3JH,H = 20.3 Hz,
Experimental
Materials and methods
3
3JH,H = 14.6 Hz, 2H, SiCHvCH2), 6.28 (dd, JH,H = 14.6 Hz,
3
2
2JH,H = 3.7 Hz, 2H, trans-H), 5.83 (dd, JH,H = 20.3 Hz, JH,H
=
NMR spectra were recorded on a Bruker DRX 500 and a Bruker 3.7 Hz, 2H, cis-H) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ =
Avance III 500 instrument. The chemical shifts (δ) were 136.6 (CHvCH2), 135.7 (o-C), 134.4 (i-C), 134.0 (CHvCH2),
measured in ppm with respect to the solvent (CDCl3: H NMR 129.6 (p-C), 128.0 (m-C) ppm. 29Si{1H} NMR (99 MHz, CDCl3):
1
δ = 7.26 ppm, 13C NMR δ = 77.16 ppm) or referenced externally δ = −20.7 ppm. EI-MS (70 eV): m/z [assignments] = 236.1,
(29Si: SiMe4; 19F: CFCl3). EI mass spectra were recorded using 209.1, 183.1, 158.1, 132.0, 105.0, 79.0. HRMS (EI, 70 eV): calcu-
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lated for C16H16Si+: 236.10158; measured: 236.10082; dev. NMR (99 MHz, CDCl3): δ = 33.0 (SiClMe2), −3.6 (Ph2Si)ppm.
[ppm]: 3.22, dev. [mmu]: 0.76.
EI-MS (70 eV): m/z [assignments] = 410.4, 303.3 [M −
(CH2CH2SiClMe2)]+, 260.9, 231.2, 250.0, 191.2, 149.1, 137.1,
123.1, 36.0.
General procedure for hydrosilylation
Diethynyldiphenylsilane (1) was dissolved in the correspon-
Bis(dichloromethylsilylethyl)diphenylsilane (7). Yield: 654 mg
ding chlorosilane. Karstedt’s catalyst (1% (wt) Pt in toluene, (98%). 1H NMR (500 MHz, CDCl3): δ = 7.51 (m, 4H, Ph-H), 7.42
1–3 drops) was added via a syringe and the pale yellow reaction (m, 6H, Ph-H), 1.23 (m, 4H, Ph2SiCH2), 1.02 (m, 4H,
mixture was stirred for 2 h at ambient temperature. Remaining CH2SiCl2Me), 0.76 (s, 6H, CH3) ppm. 13C{1H} NMR (125 MHz,
chlorosilane was removed in vacuo and the product was CDCl3): δ = 135.1 (o-C), 134.1 (i-C), 129.9 (p-C), 128.3 (m-C),
obtained analytically pure.
Divinyldiphenylsilane (2) was dissolved in Et2O (2–4 mL). NMR (99 MHz, CDCl3): δ = 33.3 (SiCl2Me), −3.4 (Ph2Si) ppm.
Chlorosilane (2.5–4 eq.) and Karstedt’s catalyst (1% (wt) Pt in EI-MS (70 eV): m/z [assignments] 466.0, 323.0
toluene, 1–3 drops) was added via a syringe and the reaction [M − (CH2CH2SiCl2Me)]+, 217.0, 183.1, 121.0, 105.0.
mixture was stirred for 3 d at ambient temperature. All volatile Bis(trichlorosilylethyl)diphenylsilane (8). Yield: 400 mg
14.4 (CH2SiCl2Me), 4.6 (Ph2SiCH2), 3.4 (CH3) ppm. 29Si{1H}
=
compounds were removed under reduced pressure and the (99%). 1H NMR (500 MHz, CDCl3): δ = 7.46 (m, 10H, Ph-H),
product was obtained analytically pure.
1.29 (s, 8H, CH2) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ =
Bis(chlorodimethylsilylvinyl)diphenylsilane
(3).
Yield: 135.0 (o-C), 132.9 (i-C), 130.3 (p-C), 128.5 (m-C), 17.6
1
704 mg (97%). H NMR (500 MHz, CDCl3): δ = 7.43 (m, 10H, (CH2SiCl3), 3.8 (Ph2SiCH2) ppm. 29Si{1H} NMR (99 MHz,
3
3
Ph-H), 7.12 (d, JH,H = 22.4 Hz, 2H, Ph2SiCH), 6.72 (d, JH,H
22.4 Hz, 2H, CHSiClMe2), 0.52 (s, 12H, CH3) ppm. 13C{1H} [assignments] = 505.9, 345.0 [M − (CH2CH2SiCl3)]+, 266.9,
NMR (125 MHz, CDCl3): 152.1 (Ph2SiCH), 147.3 217.0, 181.0, 165.0, 134.9, 105.0.
=
CDCl3): δ = 12.9 (SiCl3), −3.4 (Ph2Si) ppm. EI-MS (70 eV): m/z
δ
=
(CHSiClMe2), 135.8 (o-C), 133.2 (i-C), 130.0 (p-C), 128.2 (m-C),
1.8 (CH3) ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = 16.7
General procedure for fluorination
(SiClMe2), −24.7 (Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] In a glove box chlorosilanes 3–8 were dissolved in n-hexane
= 420.1, 405.1, 376.1, 327.1, 250.0, 217.0, 183.1, 135.1, 105.0, (2–5 mL) in a glove box. Antimony trifluoride (1.2–1.5 eq.) was
+
93.0. HRMS (EI, 70 eV): calculated for C20H26Cl2Si3 : added and the suspension was stirred for 20 h at ambient
420.07139; measured: 420.07194; dev. [ppm]: 1.31, dev. temperature. The solid residue was filtered off, and the
[mmu]: 0.55.
product was isolated by removing the solvent. Fluorosilanes 11
Bis(dichloromethylsilylvinyl)diphenylsilane (4). Yield: 1.51 g and 14 were purified by sublimation (10−2 mbar, 80 °C) and
(99%). 1H NMR (500 MHz, CDCl3): δ = 7.47 (m, 10H, Ph-H), isolated as colorless crystalline solids.
7.33 (d, 3JH,H = 22.2 Hz, 2H, Ph2SiCH), 6.69 (d, JH,H = 22.2 Hz,
Bis(fluorodimethylsilylvinyl)diphenylsilane (9). Yield: 987 mg
3
2H, CHSiCl2Me), 0.90 (s, 6H, CH3) ppm. 13C{1H} NMR (94%). 1H NMR (500 MHz, CDCl3): δ = 7.43 (m, 10H, Ph-H),
3
3
(125 MHz, CDCl3): δ = 150.2 (Ph2SiCH), 148.2 (CHSiCl2Me), 7.12 (d, JH,H = 22.8 Hz, 2H, Ph2SiCH), 6.71 (dd, JH,H
=
3
3
135.8 (o-C), 131.7 (i-C), 130.5 (p-C), 128.5 (m-C), 5.2 (CH3) ppm. 22.8 Hz, JF,H = 2.8 Hz, 2H, CHSiFMe2), 0.33 (d, JF,H = 7.3 Hz,
29Si{1H} NMR (99 MHz, CDCl3): δ = 14.1 (SiCl2Me), −21.1 12H, CH3) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ = 152.1 (d,
(Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] = 460.0, 381.9, 2JF,C = 16.4 Hz, CHSiFMe2), 147.7 (d, JF,C = 2.6 Hz, Ph2SiCH),
3
2
347.1, 270.0, 217.0, 183.1, 145.1, 105.0. HRMS (EI, 70 eV): 135.8 (o-C), 133.4 (i-C), 130.0 (p-C), 128.2 (m-C), −1.3 (d, JF,C
=
calculated for C18H20Cl4Si3 : 459.96214; measured: 459.96331; 15.6 Hz, CH3) ppm. 19F NMR (470 MHz, CDCl3): δ = −162.1
+
3
3
dev. [ppm]: 2.54, dev. [mmu]: 1.17.
(dsept, JF,H = 7.3 Hz, JF,H = 2.8 Hz, CHSiFMe2) ppm. 29Si{1H}
1
Bis(trichlorosilylvinyl)diphenylsilane (5). Yield: 1.18 g (98%). NMR (99 MHz, CDCl3): δ = 17.7 (d, JSi,F = 277.6 Hz, SiFMe2),
1H NMR (500 MHz, CDCl3): δ = 7.49 (d, JH,H = 21.9 Hz, 2H, −21.8 (Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] = 388.1,
3
3
Ph2SiCH), 7.48 (m, 10H, Ph-H), 6.65 (d, JH,H = 21.9 Hz, 2H, 285.1, 234.1, 183.1, 135.1, 105.0, 77.0. HRMS (EI, 70 eV): calcu-
CHSiCl3) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ = 152.7 lated for C20H26F2Si3 : 388.13049; measured: 388.13005; dev.
+
(Ph2SiCH), 145.1 (CHSiCl3), 135.8 (o-C), 130.9 (p-C), 130.5 (i-C), [ppm]: 1.13, dev. [mmu]: 0.44.
128.7 (m-C) ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = −6.1
Bis(difluoromethylsilylvinyl)diphenylsilane
(10).
Yield:
(SiCl3), −20.6 (Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] = 1.21 g (93%). 1H NMR (500 MHz, CDCl3): δ = 7.44 (m, 10H, Ph-H),
3
3
499.9, 423.8, 369.0, 326.9, 288.9, 243.1, 217.0, 183.1, 165.0, 7.36 (d, JH,H = 23.0 Hz, 2H, Ph2SiCH), 6.54 (dt, JH,H
=
+
3
3
131.1, 105.0. HRMS (EI, 70 eV): calculated for C16H14Cl6Si3 : 23.0 Hz, JF,H = 2.4 Hz, 2H, CHSiF2Me), 0.47 (t, JF,H = 6.1 Hz,
499.85290; measured: 499.85240; dev. [ppm]: 1.00, dev. 6H, CH3) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ = 152.7 (t,
2
[mmu]: 0.50.
3JF,C = 2.7 Hz, Ph2SiCH), 144.9 (t, JF,C = 19.5 Hz, CHSiF2Me),
2
Bis(chlorodimethylsilylethyl)diphenylsilane
(6).
Yield: 135.8 (o-C), 131.7 (p-C), 130.4 (i-C), 128.4 (m-C), −4.8 (t, JF,C
=
912 mg (96%). 1H NMR (500 MHz, CDCl3): δ = 7.50 (m, 4H, Ph-H), 17.0 Hz, CH3) ppm. 19F NMR (470 MHz, CDCl3): δ = −137.1
7.38 (m, 6H, Ph-H), 1.12 (m, 4H, Ph2SiCH2), 0.74 (m, 4H, (dq, JF,H = 6.1 Hz, JF,H = 2.4 Hz, CHSiF2Me) ppm. 29Si{1H}
3
3
CH2SiClMe2), 0.39 (s, 12H, CH3) ppm. 13C{1H} NMR (125 MHz, NMR (99 MHz, CDCl3): δ = −16.1 (t, JSi,F = 291.6 Hz, SiF2Me),
1
CDCl3): δ = 135.3 (i-C), 135.1 (o-C), 129.6 (p-C), 128.1 (m-C), −20.9 (Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] = 396.1,
11.4 (CH2SiClMe2), 3.6 (Ph2SiCH2), 1.1 (CH3) ppm. 29Si{1H} 381.1, 318.0, 289.1, 238.1, 201.1, 183.1, 145.1, 105.0, 81.0.
This journal is © The Royal Society of Chemistry 2017
Dalton Trans.

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Paper
Dalton Transactions
+
HRMS (EI, 70 eV): calculated for C18H20F4Si3 : 396.08035; a potassium fluoride 18-crown-6 mixture (1 or 2 eq.) were dis-
measured: 396.08064; dev. [ppm]: 0.73, dev. [mmu]: 0.29. solved in dichloromethane. The silicate complex was isolated
Bis(trifluorosilylvinyl)diphenylsilane (11). Yield: 970 mg by removing the solvent after stirring for several hours.
1
3
1
(86%). H NMR (500 MHz, CDCl3): δ = 7.67 (d, JH,H = 23.1 Hz,
[K-18-crown-6]+[Ph2Si(CHCHSiF3)(CHCHSiF4)]− (15). H NMR
3
3
2H, Ph2SiCH), 7.47 (m, 10H, Ph-H), 6.39 (dq, JH,H = 23.1 Hz, (500 MHz, CDCl3): δ = 7.57 (d, JH,H = 22.7 Hz, 2H, Ph2SiCH),
3JF,H = 3.4 Hz, 2H, CHSiF3) ppm. 13C{1H} NMR (125 MHz, 7.44 (m, 10H, Ph-H), 6.48 (d, 3JH,H = 22.7 Hz, 2H, CHSiFx), 3.58
CDCl3): δ = 158.8 (Ph2SiCH), 135.7 (o-C), 134.4 (q, JF,C = 25.3 (s, OCH2) ppm. 13C{1H} NMR (125 MHz, CDCl3): δ = 163.2
2
Hz, CHSiF3), 131.0 (p-C), 129.9 (i-C), 128.7 (m-C) ppm. 19F (Ph2SiCH), 135.8 (o-C), 132.2 (i-C), 130.4 (br, CHSiFx), 130.2 (p-C),
NMR (470 MHz, CDCl3): δ = −141.5 (d, JF,H = 3.4 Hz CHSiF3) 128.2 (m-C), 70.2 (OCH2) ppm. 19F NMR (470 MHz, CDCl3):
3
ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = −20.2 (Ph2Si), −78.1 δ = −137.6 (s(br), SiFx) ppm. 29Si{1H} NMR (99 MHz, CDCl3):
1
(q, JSi,F = 269.3 Hz, SiF3) ppm. EI-MS (70 eV): m/z [assign- δ = −21.4 (Ph2Si), (SiFx not observable) ppm. Elemental ana-
ments] = 404.1, 326.0, 293.1, 242.0, 216.0, 183.1, 150.0, 105.0. lysis calcd (%) for C28H38F7KO6Si3 (Mr = 726.94): C 46.26,
+
HRMS (EI, 70 eV): calculated for C16H14F6Si3 : 404.03020; H 5.27; found: C 46.27, H 5.30.
measured: 404.02995; dev. [ppm]: 0.62, dev. [mmu]: 0.25.
2[K-18-crown-6]+[Ph2Si(CHCHSiF4)2]2− (16). 1H NMR
3
Bis(fluorodimethylsilylethyl)diphenylsilane
(12).
Yield: (500 MHz, CDCl3): δ = 7.56 (m, 4H, o-Ph-H), 7.40 (d, JH,H
=
624 mg (97%). 1H NMR (500 MHz, CDCl3): δ = 7.54 (m, 4H, 22.0 Hz, 2H, Ph2SiCH), 7.24 (m, 6H, m-Ph-H, p-Ph-H), 6.62
3
Ph-H), 7.41 (m, 6H, Ph-H), 1.13 (m, 4H, Ph2SiCH2), 0.65 (m, (d(br), JH,H = 21.9 Hz, 2H, CHSiF4), 3.58 (s, OCH2) ppm.
3
4H, CH2SiFMe2), 0.25 (d, JF,H = 7.5 Hz, 12H, CH3) ppm. 13C 13C{1H} NMR (125 MHz, CDCl3): δ = 167.9 (Ph2SiCH2), 148.4
{1H} NMR (125 MHz, CDCl3): δ = 135.6 (i-C), 135.2 (o-C), 129.6 (br, CHSiF4), 136.5 (i-C), 135.9 (o-C), 128.7 (p-C), 127.4 (m-C),
2
(p-C), 128.2 (m-C), 8.7 (d, JF,C = 14.2 Hz, CH2SiFMe2), 2.8 70.3 (OCH2) ppm. 19F NMR (470 MHz, CDCl3): −121.5 [s(br),
2
(Ph2SiCH2), −1.9 (d, JF,C = 15.0 Hz, CH3) ppm. 19F NMR SiF4] ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = −24.2 (Ph2Si),
(470 MHz, CDCl3): δ = −163.0 (m, CHSiFMe2) ppm. 29Si{1H} −129.6 (SiF4) ppm. Elemental analysis calcd (%) for
1
NMR (99 MHz, CDCl3): δ = 33.1 (d, JSi,F = 280.1 Hz, SiFMe2), C40H62F8K2O12Si3 (Mr = 1049.35): C 45.78, H 5.96; found:
−3.4 (Ph2Si) ppm. EI-MS (70 eV): m/z [assignments] = 377.1, C 44.289, H 5.98.
287.1 [M − (CH2CH2SiFMe2)]+, 209.1, 197.1, 183.1, 147.1,
121.1, 105.0.
[K-18-crown-6]+[Ph2Si(CH2CH2SiF3)(CH2CH2SiF4)]− (17). 1H
NMR (500 MHz, CDCl3): δ = 7.41 (m, 10H, Ph-H), 3.57 (s,
Bis(difluoromethylsilylethyl)diphenylsilane
(13).
Yield: OCH2), 1.27 (m, 4H, Ph2SiCH2), 0.83 (m, 4H, CH2SiFx) ppm.
1
862 mg (quant). H NMR (500 MHz, CDCl3): δ = 7.48 (m, 4H, 13C{1H} NMR (125 MHz, CDCl3): δ = 135.2 (o-C), 129.4 (p-C),
Ph-H), 7.41 (m, 6H, Ph-H), 1.14 (m, 4H, Ph2SiCH2), 0.69 (m, 128.0 (m-C), 70.3 (OCH2), 3.5 (br, Ph2SiCH2) ppm (i-C not
3
4H, CH2SiF2Me), 0.32 (t, JF,H = 6.3 Hz, 6H, CH3) ppm. 13C{1H} observed due to overlap with o-C; CH2SiFx not observed due to
NMR (125 MHz, CDCl3): δ = 135.1 (o-C), 134.2 (i-C), 129.9 (p-C), line broadening). 19F NMR (470 MHz, CDCl3): −131.4 [s(br),
128.3 (m-C), 5.8 (t, 2JF,C = 15.6 Hz, CH2SiF2Me), 1.9 (Ph2SiCH2), SiFx] ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = −3.4 (Ph2Si),
2
−4.8 (t, JF,C = 16.3 Hz, CH3) ppm. 19F NMR (470 MHz, CDCl3): (SiFx not observed) ppm. Elemental analysis calcd (%) for
3
3
δ = −137.5 (dq, JF,H = 11.3 Hz, JF,H = 5.8 Hz, CH2SiF2Me) C28H42F7KO6Si3 (Mr = 730.97): C 46.01, H 5.79; found: C 46.02,
1
ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = 2.4 (t, JSi,F
299.0 Hz, SiF2Me), −3.0 (Ph2Si) ppm. EI-MS (70 eV): m/z
[assignments] = 385.1, 291.1 [M − (CH2CH2SiF2Me)]+, 233.0, (500 MHz, CDCl3): δ = 7.52 (m, 4H, o-Ph-H), 7.20 (m, 6H, m-Ph-H,
=
H 6.01.
2[K-18-crown-6]+[Ph2Si(CH2CH2SiF4)2]2− (18). 1H NMR
201.1, 183.1, 121.1, 105.0, 81.0.
Bis(trifluorosilylethyl)diphenylsilane (14). Yield: 1.42
p-Ph-H), 3.58 (s, OCH2), 1.27 (m, 4H, Ph2SiCH2), 0.74 [m(br),
g
4H, CH2SiF4] ppm. 13C{1H} NMR (125 MHz, CDCl3): δ = 138.4
(89%). 1H NMR (500 MHz, CDCl3): δ = 7.45 (m, 10H, PhH), (i-C), 135.4 (o-C), 128.3 (p-C), 127.3 (m-C), 70.3 (OCH2), 8.5 (br,
1.23 (m, 4H, Ph2SiCH2), 0.88 (m, 4H, CH2SiF3) ppm. 13C{1H} CH2SiF4), 6.2 (Ph2SiCH2) ppm. 19F NMR (470 MHz, CDCl3):
NMR (125 MHz, CDCl3): δ = 135.0 (o-C), 132.6 (i-C), 130.4 (p-C), −119.2 [s(br), SiF4] ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ =
2
128.5 (m-C), 2.0 (Ph2SiCH2), −0.3 (q, JF,C = 19.7 Hz, CH2SiF3) −4.3 (Ph2Si), −112.0 (SiF4) ppm. Elemental analysis calcd (%)
ppm. 19F NMR (470 MHz, CDCl3): δ = −139.6 (t, JF,H = 2.8 Hz for C40H66F8K2O12Si3 (Mr = 1053.39): C 45.61, H 6.32; found:
3
CH2SiF3) ppm. 29Si{1H} NMR (99 MHz, CDCl3): δ = −2.9 C 44.43, H 6.25.
1
(Ph2Si), −59.8 (q, JSi,F = 286.0 Hz, SiF3) ppm. EI-MS (70 eV):
General procedure for the conversion of fluorosilanes 11, 14
and potassium fluoride [2.2.2]cryptand complexes
m/z [assignments] = 389.1, 295.1 [M − (CH2CH2SiF3)]+, 217.0,
183.1, 150.0, 105.0.
Spray-dried potassium fluoride (55 mg, 0.95 mmol) and [2.2.2]
cryptand (100 mg, 0.27 mmol) were dissolved in acetone and
stirred 3 d at ambient temperature. The suspension was fil-
General procedure for the conversion of fluorosilanes 11, 14
and potassium fluoride 18-crown-6 complexes
Spray-dried potassium fluoride (225 mg, 3.87 mmol) and tered, and the solvent was removed from the filtrate under
1
18-crown-6 (1.00 g, 3.78 mmol) were dissolved in dichloro- reduced pressure. H NMR (300 MHz, acetone-d6): δ = 3.64 (s,
methane and stirred overnight at ambient temperature. The 12H, CH2), 3.61 (m, 12H, CH2), 2.61 (m, 12H, CH2) ppm.
suspension was filtered, and the solvent was removed from the 19F NMR (282 MHz, acetone-d6): δ = −109.2 ppm. Fluorosilane
filtrate under reduced pressure. In a glove box fluorosilane and and potassium fluoride [2.2.2]cryptand mixture (1 or 2 eq.)
Dalton Trans.
This journal is © The Royal Society of Chemistry 2017

Table 7 Crystallographic data for 1, 5, 11, 14, 15, 20 and 22
1
3
5
11
14
15
17
20
22
Empirical formula
Mr
F(000)
Crystal system
Space group
a [Å]
b [Å]
c [Å]
α [°]
β [°]
C16H12Si
232.35
488
Monoclinic
P21/c
9.06686(12)
7.54672(9)
19.5187(2)
90
101.1855(13)
90
C20H26Cl2Si3
421.58
888
Monoclinic
C2/c
17.3643(4)
11.5112(3)
11.4420(3)
90
90.416(3)
90
C16H14Cl6Si3
503.26
1016
Monoclinic
C2/c
17.2081(9)
11.5831(8)
11.3044(7)
90
90.810(5)
90
C16H14F6Si3
404.54
824
Monoclinic
P21/c
6.69282(16)
12.4642(2)
22.3387(4)
90
98.414(2)
90
C16H18F6Si3
408.57
840
Monoclinic
P21/n
9.58517(10)
15.67457(13)
13.23279(17)
90
109.1776(12)
90
1877.81(4)
4
C28H38F7KO6Si3
726.95
756
Monoclinic
P21
9.6707(3)
14.7072(3)
12.2271(3)
90
100.137(3)
90
1711.91(8)
2
C28H42F7KO6Si3
730.98
764
Monoclinic
P21
9.62226(18)
14.66422(19)
12.5895(2)
90
99.8129(18)
90
1750.43(5)
2
C52H86F8K2N4O12Si3
1273.71
1348
Triclinic
ˉ
P1
11.25235(13)
14.6618(2)
20.6823(2)
102.4812(10)
98.9460(9)
105.1347(11)
3133.60(7)
2
C52H90F8K2N4O12Si3
1277.74
1356.0
Triclinic
ˉ
P1
11.42848(16)
14.5458(2)
20.6353(3)
101.0019(12)
99.0164(12)
106.2033(12)
3152.30(8)
2
γ [°]
V [Å3]
Z
1310.19(3)
4
1.178
2287.02(10)
4
1.224
2253.0(2)
4
1.484
1843.44(7)
4
1.458
ρcalcd. [g cm−3
]
1.445
1.410
1.387
1.350
1.346
Radiation [Å]
0.71073
0.153
60.04
−12 ≤ h ≤ 12
−10 ≤ k ≤ 10
−27 ≤ l ≤ 27
73 396
3827
0.0315
3646
0.71073
0.443
52.78
−21 ≤ h ≤ 21
−14 ≤ k ≤ 14
−14 ≤ l ≤ 14
44 651
2333
0.0814
2003
1.54184
8.486
133.94
−20 ≤ h ≤ 18
−9 ≤ k ≤ 13
−13 ≤ l ≤ 13
7654
2008
0.0427
1865
1.54184
2.896
144.25
−8 ≤ h ≤ 8
−15 ≤ k ≤ 15
−27 ≤ l ≤ 27
28 265
3633
0.0471
3184
1.54184
2.843
143.98
−11 ≤ h ≤ 11
−19 ≤ k ≤ 19
−16 ≤ l ≤ 16
53 527
3697
0.0189
3621
226
0.0284
0.0708
0.0288
0.0711
1.032
0.68/−0.45
—
1.54184
3.056
143.98
−11 ≤ h ≤ 10
−18 ≤ k ≤ 18
−15 ≤ l ≤ 15
30 331
6734
0.0528
6155
417
1.54184
2.990
144.0
−11 ≤ h ≤ 11
−18≤ k ≤ 18
−15 ≤ l ≤ 15
31 114
6885
0.0369
6665
443
0.71073
0.291
60.16
−15 ≤ h ≤ 15
−20 ≤ k ≤ 20
−29 ≤ l ≤ 29
183 781
18 403
0.0333
16 083
1000
0.0368
1.54184
2.587
144.7
−14 ≤ h ≤ 14
−17 ≤ k ≤ 17
−25 ≤ l ≤ 25
68 977
12 436
0.0252
11 890
959
0.0308
0.0802
0.0321
0.0813
1.048
0.40/−0.41
—
μ [mm−1
2θmax [°]
]
Index range h
Index range k
Index range l
Refl. collected
Indep. refl.
Rint
Obs. refl., I > 2σ(I)
Parameters
R1, I > 2σ(I)
wR2, I > 2σ(I)
R1 (all data)
wR2 (all data)
GoF
154
116
117
258
0.0318
0.0922
0.0333
0.0932
1.133
0.0323
0.0826
0.0383
0.0848
1.076
0.0595
0.1419
0.0630
0.1454
1.079
0.0390
0.1000
0.0450
0.1048
1.045
0.0425
0.1072
0.0478
0.1116
0.0466
0.1284
0.0476
0.1299
0.0899
0.0435
0.0935
1.036
1.038
1.032
ρmax/ρmin [e Å−3
Remarks
]
0.42/−0.22
—
0.40/−0.28
—
1.12/−0.71
—
0.42/−0.35
0.29/−0.72
0.50/−0.29
0.71/−0.78
a
b
c
d
CCDC number
1520262
1520263
1520264
1520265
1520266
1520267
1520268
1520269
1520270
Remarks: a Disorder of F(1), F(2) and F(3) on two positions (58 : 42); disorder of Si(3), F(4), F(5), F(6) and C(4) on two positions (83 : 17). b Refined as a two component inversion twin (BASF
0.497); disorder of F(5), F(6) and F(7) on two positions (81 : 19). c Disorder of the entire silicate anion with ratio 83 : 17. d Disorder of F(5), F(6), F(7) and F(8) over two sites (54 : 46); disorder of
C(1) to C(6) over two sites (67 : 37); disorder of the second cation excluding K(2), O(11) and O(12) over two sites (75 : 25).

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were dissolved in acetone-d6 and sonicated in a Young NMR 17) and acetone (20, 22). They were coated with paratone-N oil,
tube for 30 min.
selected, mounted on a glass fiber and transferred onto the
(19). goniometer and into the cryostream of the diffractometer.
{K-[2.2.2]cryptand}+[Ph2Si(CHCHSiF3)(CHCHSiF4)]−
1H NMR (500 MHz, acetone-d6): δ = 7.54 (m, 4H, o-Ph-H), 7.36 Data collections were performed at 100.0(2) K on a SuperNova
(d, 3JH,H = 22.0 Hz, 2H, Ph2SiCH), 7.36 (m, 6H, m-Ph-H, p-Ph-H), diffractometer, using monochromated Cu-Kα radiation for
3
6.62 (d, JH,H = 22.0 Hz, 2H, CHSiFx), 3.63 (s, 12H, CH2), 3.59 compounds 5, 11, 14, 15, 17 and 22 and Mo-Kα radiation for
(m, 12H, CH2), 2.60 (m, 12H, CH2) ppm. 13C{1H} NMR compounds 1, 3 and 20.
(125 MHz, acetone-d6): δ = 162.9 (Ph2SiCH), 137.0 (i-C), 136.4
Using Olex2 the structures were solved by direct methods
(o-C), 129.8 (p-C), 128.5 (m-C), 71.2 (CH2), 68.4 (CH2), 54.7 and refined by full-matrix least-squares cycles (program
(CH2), (CHSiFx not observable) ppm. 19F NMR (470 MHz, SHELX-97).39 Crystal and refinement details, as well as CCDC
acetone-d6): δ = −120.1 [s(br), SiFx] ppm. 29Si{1H} NMR numbers are provided in Table 7. CCDC 1520262–1520270
(99 MHz, acetone-d6): δ = −23.5 (Ph2Si), (SiFx not observable) contain the supplementary crystallographic data for this
ppm. Elemental analysis calcd (%) for C34H50F7KN2O6Si3 (Mr = paper.
839.11): C 48.67, H 6.01, N 3.34; found: C 49.05, H 6.39,
N 3.22.
2{K-[2.2.2]cryptand}+[Ph2Si(CHCHSiF4)]2− (20). 1H NMR
Acknowledgements
(500 MHz, acetone-d6): δ = 7.56 (m, 4H, o-Ph-H), 7.32 (d, 3JH,H
=
21.9 Hz, 2H, Ph2SiCH), 7.32 (m, 6H, m-Ph-H, p-Ph-H), 6.68 (d, The authors thank Dipl. Ing. Klaus-Peter Mester and Gerd
3JH,H = 21.9 Hz, 2H, CHSiF4), 3.62 (s, 12H, CH2), 3.58 (m, 12H, Lipinski for recording NMR spectra, Brigitte Michel for
CH2), 2.58 (m, 12H, CH2) ppm. 13C{1H} NMR (125 MHz, measuring CHN analyses, as well as Heinz-Werner Patruck for
acetone-d6): δ = 160.9 (Ph2SiCH), 146.4 (br, CHSiF4), 138.2 (i-C), measuring mass spectra. We gratefully acknowledge financial
136.5 (o-C), 129.4 (p-C), 128.2 (m-C), 71.2 (CH2), 68.4 (CH2), support from the Deutsche Forschungsgemeinschaft (DFG).
54.6 (CH2) ppm. 19F NMR (470 MHz, acetone-d6): δ = −119.8 (s,
SiF4) ppm. 29Si{1H} NMR (99 MHz, acetone-d6): δ = −23.5
(Ph2Si), −130.2 (SiF4) ppm. Elemental analysis calcd (%) for
C52H86F8K2N4O12Si3 (Mr = 1273.70): C 49.03, H 6.81, N 4.40;
Notes and references
found: C 49.34, H 6.98, N 4.40.
1 C. J. Pedersen, J. Am. Chem. Soc., 1967, 89, 7017–7036.
2 (a) J.-H. Lamm, J. Horstmann, J. H. Nissen,
J.-H. Weddeling, B. Neumann, H.-G. Stammler and
N. W. Mitzel, Eur. J. Inorg. Chem., 2014, 4294–4301;
(b) J. Chmiel, B. Neumann, H.-G. Stammler and
N. W. Mitzel, Chem. – Eur. J., 2010, 16, 11906–11914.
3 (a) M. M. G. Antonisse and D. N. Reinhoudt, Chem.
Commun., 1998, 443–447; (b) J. W. Steed, Chem. Soc. Rev.,
2009, 38, 506–519; (c) P. D. Beer and P. A. Gale, Angew.
Chem., Int. Ed., 2001, 40, 486–516.
4 (a) C. R. Wade, A. E. J. Broomsgrove, S. Aldridge and
F. P. Gabbaï, Chem. Rev., 2010, 110, 3958–3984;
(b) T. W. Hudnall, C.-W. Chiu and F. P. Gabbaï, Acc. Chem.
Res., 2009, 42, 388–397; (c) H. Zhao and F. P. Gabbaï,
Organometallics, 2012, 31, 2327–2335; (d) Z. Li,
K. Chansaenpak, S. Liu, C. R. Wade, P. S. Conti and
F. P. Gabbaï, MedChemComm, 2012, 3, 1305–1308;
(e) J. M. Koomen, J. E. Lucas, M. R. Haneline,
J. D. Beckwith King, F. P. Gabbaï and D. H. Russell,
Int. J. Mass Spectrom., 2003, 225, 225–231; (f) H. Zhao and
F. P. Gabbaï, Nat. Chem., 2010, 2, 984–990; (g) M. Hirai and
F. P. Gabbaï, Angew. Chem., Int. Ed., 2015, 54, 1205–1209;
(h) J. S. Jones, C. R. Wade and F. P. Gabbaï,
Organometallics, 2015, 34, 2647–2654; (i) M. Hirai,
M. Myahkostupov, F. N. Castellano and F. P. Gabbaï,
Organometallics, 2016, 35, 1854–1860.
{K-[2.2.2]cryptand}+[Ph2Si(CH2CH2SiF3)(CH2CH2SiF4)]− (21).
1H NMR (500 MHz, acetone-d6): δ = 7.56 (m, 4H, o-Ph-H), 7.34
(m, 6H, m-Ph-H, p-Ph-H), 3.62 (s, 12H, CH2), 3.58 (m, 12H,
CH2), 2.59 (m, 12H, CH2), 1.29 (m, 4H, Ph2SiCH2), 0.75 (m, 4H,
CH2SiFx) ppm. 13C{1H} NMR (125 MHz, acetone-d6): δ = 139.4
(i-C), 136.0 (o-C), 129.1 (p-C), 128.2 (m-C), 71.2 (CH2), 68.3
(CH2), 54.6 (CH2), 9.4 (CHSiFx), 6.7 (Ph2SiCH2) ppm. 19F NMR
(470 MHz, acetone-d6): δ = −123.7 [s(br), SiFx] ppm. 29Si{1H}
NMR (99 MHz, acetone-d6): δ = −3.9 (Ph2Si), (SiFx not
observed) ppm. Elemental analysis calcd (%) for
C34H54F7KN2O6Si3 (Mr = 843.15): C 48.43, H 6.46, N 3.32;
found: C 48.48, H 6.87, N 3.80.
2{K-[2.2.2]cryptand}+[Ph2Si(CH2CH2SiF4)]2− (22). 1H NMR
(500 MHz, acetone-d6): δ = 7.57 (m, 4H, o-Ph-H), 7.29 (m, 6H,
m-Ph-H, p-Ph-H), 3.62 (s, 12H, CH2), 3.58 (m, 12H, CH2), 2.58
(m, 12H, CH2), 1.28 (m, 4H, Ph2SiCH2), 0.65 (m, 4H, CH2SiF4)
ppm. 13C{1H} NMR (125 MHz, acetone-d6): δ = 140.0 (i-C),
136.0 (o-C), 128.9 (p-C), 128.1 (m-C), 71.2 (CH2), 68.3 (CH2),
54.6 (CH2), 10.4 (CHSiF4), 7.4 (Ph2SiCH2) ppm. 19F NMR
(470 MHz, acetone-d6): δ = −117.3 (s, SiF4) ppm. 29Si{1H} NMR
(99 MHz, acetone-d6): δ = −4.1 (Ph2Si), −113.6 (SiF4) ppm.
Elemental analysis calcd (%) for C52H90F8K2N4O12Si3 (M =
1277.73): C 48.88, H 7.10, N 4.38; found: C 48.65, H 7.16,
N 4.31.
Crystallography
5 D. Brondani, F. H. Carré, R. J. P. Corriu, J. J. E. Moreau and
M. Wong Chi Man, Angew. Chem., Int. Ed. Engl., 1996, 35,
324.
Suitable crystals of compounds 1, 3, 5, 11, 14, 15, 17, 20 and
22 were obtained by slow evaporation of saturated solutions of
THF (1), n-hexane (3, 5), Et2O (11, 14), dichloromethane (15,
6 M. E. Jung and H. Xia, Tetrahedron Lett., 1988, 29, 297–300.
Dalton Trans.
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View Article Online
Dalton Transactions
Paper
7 K. Tamao, T. Hayashi and Y. Ito, Organometallics, 1992, 11, 20 B. Cordero, V. Gómez, A. E. Platero-Prats, M. Revés,
2099–2114.
J. Echeverría, E. Cremades, F. Barragán and S. Alvarez,
Dalton Trans., 2008, 21, 2832–2838.
21 (a) A. F. Holleman, E. Wiberg and N. Wiberg, Lehrbuch der
Anorganischen Chemie, de Gruyter, Berlin, 1985, pp. 91–100;
(b) G. Dierker, J. Ugolotti, G. Kehr, R. Fröhlich and
G. Erker, Adv. Synth. Catal., 2009, 351, 1080–1088.
8 S. Aoyagi, K. Tanaka and Y. Takeuchi, J. Chem. Soc., Perkin.
Trans. 2, 1994, 1549–1553.
9 R. Altmann, O. Gausset, D. Horn, K. Jurkschat and
M. Schürmann, Organometallics, 2000, 19, 430–443.
10 (a) K. Tamao, T. Hayashi and Y. Ito, J. Organomet. Chem.,
1996, 506, 85–91; (b) Y. Kim, M. Kim and F. P. Gabbaï, 22 A. A. Anisimov, Y. N. Kononevich, A. A. Korlyukov,
Org. Lett., 2010, 12, 600–602; (c) A. Kawachi, A. Tani,
J. Shimada and Y. Yamamoto, J. Am. Chem. Soc., 2008, 130,
4222–4223.
D. E. Arkhipov, E. G. Kononova, A. S. Peregudov,
O. I. Shchegolikhina and A. M. Muzafarov, J. Organomet.
Chem., 2014, 772, 79–83.
11 D. Dakternieks, A. Duthie, R. Altmann, K. Jurkschat and 23 S. W. Carr, M. Motevalli, D. L. Ou and A. C. Sullivan,
M. Schürmann, Organometallics, 1998, 17, 5858–5866. J. Mater. Chem., 1997, 7, 865–872.
12 (a) R. Panisch, M. Bolte and T. Müller, J. Am. Chem. Soc., 24 (a) N. W. Mitzel, P. T. Brain, M. Hofmann, D. W. H. Rankin,
2006, 128, 9676–9682; (b) C. L. Dorsey and F. P. Gabbaï,
Organometallics, 2008, 27, 3065–3069.
13 D. Dakternieks, A. Duthie, R. Altmann, K. Jurkschat and
M. Schürmann, Organometallics, 1997, 16, 5716–5723.
14 A. S. Wendji, C. Dietz, S. Kühn, M. Lutter, D. Schollmeyer,
W. Hiller and K. Jurkschat, Chem. – Eur. J., 2016, 22, 404–416.
R. Schröck and H. Schmidbaur, Z. Naturforsch., 2002, 57B,
202–214; (b) B. F. Johnston, N. W. Mitzel, D. W. H. Rankin,
H. E. Robertson, C. Rüdinger and H. Schmidbaur,
Dalton Trans., 2005, 2292–2299; (c) J. E. Laska, P. Kaszynski
and S. J. Jacobs, Organometallics, 1998, 17, 2018–
2026.
15 (a) E. Weisheim, B. Neumann, H.-G. Stammler and 25 N. W. Mitzel, K. Vojinovic, T. Foerster, H. E. Robertson,
N. W. Mitzel, Z. Anorg. Allg. Chem., 2016, 642, 329–334;
(b) E. Weisheim, L. Büker, B. Neumann, H.-G. Stammler
K. B. Borisenko and D. W. H. Rankin, Chem. – Eur. J., 2005,
11, 5114–5125.
and N. W. Mitzel, Dalton Trans., 2016, 45, 198–207; 26 (a) B. N. Menshutkin, Zh. Russ. Fiz. Khim. Ova. Chast.
(c) E. Weisheim, C. G. Reuter, P. Heinrichs,
Y. V. Vishnevskiy, A. Mix, B. Neumann, H.-G. Stammler and
N. W. Mitzel, Chem. – Eur. J., 2015, 21, 12436–12448;
(d) E. Weisheim, H.-G. Stammler and N. W. Mitzel,
Z. Naturforsch., B: Chem. Sci., 2016, 71, 77–79.
Khim., 1911, 43, 1298; (b) W. Smith and G. W. Davis,
J. Chem. Soc. Trans., 1882, 41, 411; (c) G. Peyronel,
S. Buggani and I. M. Vezzosi, Gazz. Chim. Ital., 1968, 98,
147; (d) G. Bombieri, G. Peyronel and I. M. Vezzosi, Inorg.
Chim. Acta, 1972, 6, 349; (e) A. Demalde, A. Mangia,
M. Nardelli, G. Pelizzi and M. E. Vidoni Tani, Acta
Crystallogr. Sect. B: Struct. Crystallogr. Cryst. Chem., 1972,
28, 147; (f) J. T. Szyamnski and R. Hulme, Acta. Crystallogr.,
Sect. B: Struct. Crystallogr. Cryst. Chem., 1969, 28, 753;
(g) S. Pohl, W. Saak and D. Haase, Angew. Chem., 1987, 99,
462, (Angew. Chem., Int. Ed. Engl., 1987, 26, 467);
(h) H. Schmidbaur, R. Nowak, B. Huber and G. Müller,
Organometallics, 1987, 6, 2266.
16 (a) J.-H. Lamm, J. Horstmann, H.-G. Stammler,
N. W. Mitzel, Y. A. Zhabanov, N. V. Tverdova, A. A. Otlyotov,
N. I. Giricheva and G. V. Girichev, Org. Biomol. Chem.,
2015, 13, 8893–8905; (b) A. Nieland, J.-H. Lamm, A. Mix,
B. Neumann, H.-G. Stammler and N. W. Mitzel, Z. Anorg.
Allg. Chem., 2014, 640, 2484–2491; (c) J.-H. Lamm,
J. Glatthor, J.-H. Weddeling, A. Mix, J. Chmiel,
B. Neumann, H.-G. Stammler and N. W. Mitzel, Org.
Biomol. Chem., 2014, 12, 7355–7365.
27 F. H. Carr and E. A. Price, Biochem. J., 1926, 20, 497–501.
17 E. Weisheim, A. Schwartzen, L. Kuhlmann, B. Neumann, 28 (a) V. Plack, P. Sakhaii, A. Fischer, P. G. Jones,
H.-G. Stammler and N. W. Mitzel, Eur. J. Inorg. Chem.,
2016, 16, 1257–1266.
18 (a) U. Krüerke, J. Organomet. Chem., 1970, 21, 83–90;
(b) S. D. Rosenberg, J. J. Walburn, T. D. Stankovich,
R. Schmutzler, K. Tamao and G.-R. Sun, J. Organomet.
Chem., 1998, 553, 111–114; (b) H. Sakurai, Y. Nakadaira,
H. Tobita, T. Ito, K. Toriumi and H. Ito, J. Am. Chem. Soc.,
1982, 104, 300–302.
A. E. Balint and H. E. Ramsden, J. Org. Chem., 1957, 22, 29 N. Rani, P. Sengupta, A. K. Singh and R. J. Butcher,
1200–1202; (c) M. Fischer and R. Tacke, Organometallics,
2013, 32, 7181–7185.
Polyhedron, 2007, 26, 5477–5483.
30 R. Pietschnig and K. Merz, Chem. Commun., 2001, 1210–
19 Dichlorodiphenylsilane (97%) must be distilled freshly to
1211.
inhibit the formation of any volatile byproducts. The 31 (a) C. Chuit, R. J. P. Corriu, C. Reye and J. C. Young, Chem.
cheaper reaction route is a single deprotonation of acety-
lene gas with n-BuLi at −30 °C followed by the addition of
dichlorodiphenylsilane in THF. To separate the acetylene
from the acetone contained the gas cylinder, we used two
−78 °C cooling traps (CAUTION: the traps must not be in
Rev., 1993, 93, 1371–1448; (b) R. Damrauer, B. O’Connell,
S. E. Danahey and R. Simon, Organometallics, 1989, 5,
1167–1171; (c) S. Spirk, F. Belaj, M. Nieger, H. Köfeler,
G. N. Rechberger and R. Pietschnig, Chem. – Eur. J., 2009,
15, 9521–9529.
order to prohibit the condensation of acetylene and avoid 32 Albeit THF was reported to be used, the crystal structure of
the resulting explosion hazard). However, the use of the
Grignard species enhanced the yield from 70 to 91%.
heptafluorotrisilacyclohexane anion displays a dichloro-
methane molecule.5.
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33 S. E. Johnson, R. O. Day and R. R. Holmes, Inorg. Chem., 38 We generated {K·[2.2.2]cryptand}+F− by using spray dried
1989, 28, 3182–3189.
potassium fluoride and [2.2.2]cryptand in dichloro-
methane. Albeit the complexation of K+ could easily be
34 (a) R. Damrauer and S. E. Danahey, Organometallics, 1986,
5, 1490–1494; (b) S. Yamaguchi, S. Akiyama and K. Tamao,
Organometallics, 1999, 18, 2851–2854; (c) P. D. Price,
M. J. Bearpark, G. S. McGrady and J. W. Steed, Dalton
Trans., 2008, 271–282.
35 (a) D. Schomburg, J. Organomet. Chem., 1981, 221, 137–141;
(b) X. Ou and A. F. Janzen, Inorg. Chem., 1997, 36, 392–395;
(c) K. Ebata, T. Inada, C. Kabuto and H. Sakurai, J. Am.
Chem. Soc., 1994, 116, 3595–3596.
36 R. R. Holmes, Chem. Rev., 1996, 96, 927–950.
37 (a) B. Dietrich and J. M. Lehn, Tetrahedron Lett., 1973, 15,
1225–1228; (b) S. Yamaguchi, S. Akiyama and K. Tamao,
J. Am. Chem. Soc., 2000, 122, 6793–6794.
1
monitored via H NMR spectroscopy, a 19F NMR resonance
could not be detected. The X-ray structure analysis of this
compound displays its chloride salt {K·[2.2.2]cryptand}+Cl−
indicating that an anion exchange took place during the
reaction. After preparing the {K·[2.2.2]cryptand}+F− salt in
acetone we were able to detect a 19F NMR signal at δ =
−109.2 ppm.
39 (a) O. V. Dolomanov, L. J. Bourhis, R. J. Gildea,
J. A. K. Howard and H. Puschmann, J. Appl.
Crystallogr., 2009, 42, 339–341; (b) G. N. Sheldrick, Acta
Crystallogr., Sect. A: Fundam. Crystallogr., 2008, 64,
112–122.
Dalton Trans.
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