Syntheses of branched-polyfluoroalkylsilanes

Article abstract of DOI:10.1016/S0022-1139(99)00193-1

Three types of branched-type polyfluoroalkylsilanes, trichloro[4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoroheptyl] silane (D3CL3), monochlorodimethyl[4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoroheptyl] silane (D3CL), triethoxy[4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoroheptyl]silane (D3Et3), could be synthesized using the hydrosilylation reaction of the branched-type polyfluoroalkene and corresponding silanes in the presence of hydrogen hexachloroplatinate (IV) as a catalyst. The hydrosilylation reaction of 4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoro-1-heptene with silanes produced only β-addition compounds highly regioselectively. From the MM2 calculation, it was found that the branched-polyfluoroalkylsilane has a bent structure at quaternary carbon.

Full text of DOI:10.1016/S0022-1139(99)00193-1

Journal of Fluorine Chemistry 101 (2000) 39±43
Syntheses of branched-poly¯uoroalkylsilanes
a
Takeo Konakahara , Shin-ichiro Okada , Jun Furuhashi ,
a
a
a
Jun-ichi Sugaya , Takashi Monde , Nobuyuki Nakayama ,
b
b
b
Koji Yano Fujito Nemoto , Toshiro Kamiusuki
Department of Industrial and Engineering Chemistry, Faculty of Science and Technology,
b,*
a
Science University of Tokyo, Noda, Chiba 278-8510, Japan
Central Research Laboratory, NEOS Company, Kohsei, Kohka, Shiga 520-3213, Japan
b
Received 17 November 1998; accepted 3 August 1999
Abstract
Three types of branched-type poly¯uoroalkylsilanes, trichloro[4,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl] silane (D3CL3),
monochlorodimethyl[4,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl]silane (D3CL), triethoxy[4,4-bis(tri¯uoromethyl)-
5
,5,6,6,7,7,7-hepta¯uoroheptyl]silane (D3Et3), could be synthesized using the hydrosilylation reaction of the branched-type
poly¯uoroalkene and corresponding silanes in the presence of hydrogen hexachloroplatinate (IV) as a catalyst. The hydrosilylation
reaction of 4,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoro-1-heptene with silanes produced only b-addition compounds highly
regioselectively. From the MM2 calculation, it was found that the branched-poly¯uoroalkylsilane has a bent structure at quaternary
carbon. # 2000 Elsevier Science S.A. All rights reserved.
Keywords: Branched-poly¯uoroalkylsilane; Fluorinated compounds; MM2 calculation
1
. Introduction
Linear-type poly¯uoroalkylsilanes have been synthesized
by the hydrosilylation of ¯uorinated alkenes with various
silanes for modi®cation of surface of various materials [1±
Scheme 1.
1
0]. The molecular structure is shown in Scheme 1.
were carried out in an ampule or under an atmosphere of
puri®ed nitrogen or argon to preclude oxygen and moisture.
Although these compounds are very useful for modi®cation
of the surface, there are some synthetic and technical
problems. CF ±Si bonds are not dif®cult to form but per-
2
2
.1. Materials
¯
uoroalkylsilanes can be relatively unstable thermally
because of facile b- or a-F-silane elimination [11].
In this paper, the synthesis of three types of branched-
poly¯uoroalkylsilanes have been studied using the hydro-
silylation reaction of the readily available hexa¯uoropropy-
lene dimer, per¯uoro(2-methyl-2-pentene) [12±17].
Trichlorosilane, dimethylmonochlorosilane and triethox-
ysilane were purchased from Tokyo Kasei Kogyo and were
used without further puri®cation. Hydrogen hexachloropla-
tinate (IV) was purchased from Kojima Chemicals.
Dimethylacetamid (DMA), potassium ¯uoride, potassium
iodide, allylbromide, sodium sulfate and sodium hydrogen-
sulfate (Kanto Chemical) were of reagent grade and used
without further puri®cation. Per¯uoro(2-methyl-2-pentene)
2
. Experimental
(
D-2) was obtained from NEOS.
Special precautions were adopted in order to avoid hydro-
lysis of the starting materials and products; all experiments
2
.2. Measurements
*
IR spectra were measured in liquid ®lm with a Hitachi
1
260-50 type spectrophotometer. H-NMR was run in CCl
Corresponding author. Tel.: ‡81-748-75-3161; fax: ‡81-748-75-0418.
E-mail address: fluofix@neos.co.jp (T. Kamiusuki)
4
0022-1139/00/$ ± see front matter # 2000 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 2 - 1 1 3 9 ( 9 9 ) 0 0 1 9 3 - 1

4
0
T. Konakahara et al. / Journal of Fluorine Chemistry 101 (2000) 39±43
with tetramethylsilane (TMS) as an internal standard using a
JEOL PMX-60 Si (60 MHz) spectrometer at room tempera-
2.4.2. Method B (ampule)
4,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoro-1-hep-
tene (11.6 g, 32.2 mmol) and trichlorosilane (6.77 g,
50.1 mmol) were blended in a glass ampule to the rigorous
exclusion of moisture and frozen under argon atmosphere.
After adding hydrogen hexachloroplatinate (IV) (9.4 Â
1
ture. F-NMR was recorded on a JEOL JNM-FX-90Q
9
with CFCl as an internal standard at room temperature.
3
Mass spectra (MS) were measured (at 70 eV) with a Hitachi
M-80A GC-MS spectrometer and data were evaluated
using a Hitachi M-003 data processing system. Elemental
analysis was performed at Institute of Physical and
Chemical Research (Wako, Japan). Gas chromatography
was performed with a Hitachi 663-30 (G-100 40 m column,
�
2
� 4
10 g, 2.30 Â 10 mol) the mixture was sealed under
reduced pressure and then was allowed to react at 1008C
for 3 h. The product, trichloro[4,4-bis(tri¯uoromethyl)-
5,5,6,6,7,7,7-hepta¯uoroheptyl] silane (14.3 g), was ob-
tained as a colorless liquid by fractional distillation under
reduced pressure.
�
6
®
lm thickness 2.0 Â 10 m, i.d. 1.2 mm, FID) and inten-
sities were measured with a Hitachi D-2500 chromato
integrator.
Bp 1118C/6916 Pa; IR (Neat) 1480 (SiCH ), 815 (SiCl),
2
�
1 1
1
1
340±1150 (CF ) cm ; H-NMR ꢀ ˆ 1.4 (2H, m, SiCH ),
3
2
19
.6±2.5 (4H, m, CH CH ); F-NMR ꢀ ˆ 69.2 (6F, se,
2 2
2.3. Synthesis of 4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-
heptafluoro-1-heptene (DAL), C F C(CF ) CH CH=CH
C(CF ) , J ˆ 10 Hz), 80.9 (3F, t, CF , J ˆ 10 Hz), 107.5
3
2
3
(2F, m, CCF ), 123.2 (2F, m, CF ).
2 2
3
7
3 2
2
DMA (315 g) as a solvent and potassium ¯uoride (122 g,
.1 mol) were stirred slowly throughout in a four-necked
000 ml ¯ask connected with a re¯ux condenser and drop-
ping funnel at 110±1208C for 4 h under nitrogen atmo-
sphere. After adding potassium iodide (9.8 g, 0.06 mol), the
mixture was further heated for 6 h. After cooling down to
room temperature per¯uoro(2-methyl-2-pentene) (D-2,
2.5. Synthesis of monochlorodimethyl[4,4-
bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoroheptyl]silane
(D3CL), triethoxy[4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-
heptafluoroheptyl]silane (D3Et3),
2
1
C F C(CF ) CH CH CH Si(CH ) Cl,
3
7
3 2
2
2
2
3 2
C F C(CF ) CH CH CH Si(OC H )
2 5 3
3
7
3 2
2
2
2
4
50 g, 1.50 mol) and allylbromide (163.3 g, 1.35 mol) were
The preparation procedures and puri®cation techniques
were almost the same as those for trichloro[4,4-bis(tri¯uoro-
methyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl]silane.
added to the mixture, which was then subjected to stepwise
heating, 40±458C, 11 h, 50±558C, 10 h and 55±658C, 11 h.
The resultant mixture was ®ltered and dried with sodium
sulfate and sodium hydrogensulfate. The ®nal product, 4, 4-
bis(tri¯uoromethyl)-5, 5, 6, 6, 7, 7, 7-hepta¯uoro-1-heptene
Monochlorodimethyl[4,4-bis(tri¯uoromethyl)-
5,5,6,6,7,7,7-hepta¯uoroheptyl]silane was
a
colorless
liquid: Bp 598C/266 Pa; IR (Neat) 1470 (SiCH ), 850±
2
�
1
1
(187 g), was obtained as a colorless liquid by fractional
distillation [16].
800 (SiCH ), 1340±1110 (CF ) cm ; H-NMR ꢀ ˆ 0.4
3
3
(6H, s, CH ), 0.8 (2H, m, SiCH ), 1.4±2.4 (4H, m,
3 2
19
Bp 119.58C; IR (Neat) 1645 (C=C), 1340±1150 (CF )
CH CH ); F-NMR ꢀ ˆ 64.0 (6F, se, C(CF ) , J ˆ 10 Hz),
3
2
2
3 2
�
1 1
cm ; H-NMR ꢀ ˆ 2.95 (1H, m, J ˆ 7 Hz), 4.9±5.3 (2H,
80.9 (3F, t, CF , J ˆ 10 Hz), 107.4 (2F, m, CCF ), 123.2 (2F,
2
3
2
1
9
m), 5.4±6.1 (1H, m); F-NMR ꢀ ˆ 69.2 (6F, se, C(CF ) ,
m, CF ).
Triethoxy[4,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta-
¯uoroheptyl]silane was a colorless liquid: Bp 87.58C/
3
2
J ˆ 10 Hz), 80.9 (3F, t, CF , J ˆ 10 Hz), 107.5 (2F, m,
3
CCF ), 123.2 (2F, m, CF ).
2
2
2
cm
66 Pa; IR (Neat) 1110±1080 (SiO), 1340±1120 (CF)
�
1
1
;
H-NMR ꢀ ˆ 0.58 (2H, t, SiCH , J ˆ 6.8 Hz),
2
2
5
.4. Synthesis of trichloro[4,4-bis(trifluoromethyl)-
,5,6,6,7,7,7-heptafluoroheptyl] silane (D3CL3),
1.16 (9H, t, CH , J ˆ 7.0 Hz), 1.4±2.5 (4H, m, CH CH ),
3 2 2
19
3.70 (6H, q, CH , J ˆ 7.0 Hz); F-NMR ꢀ ˆ 63.9 (6F, se,
2
C F C(CF ) CH CH CH SiCl
2
C(CF ) , J ˆ 10 Hz), 80.8 (3F, t, CF , J ˆ 10 Hz), 107.3
3
7
3 2
2
2
3
3 2
3
(
2F, m, CCF ), 123.1 (2F, m, CF ); MS (EI, 70 eV) m/z
2 2
2
.4.1. Method A (open)
,4-bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoro-1-hep-
tene (19.1 g, 53.2 mmol) and hydrogen hexachloroplatinate
524(M ‡ 1, 1%), 523 (M‡, 4), 163 (Si(OEt) ‡, 100);
3
4
elemental analysis: calculated for C H F SiO (C
21 13
15
3
33.36%, H 4.04%, F 47.10%), found (C 33.98%, H
4.01%, F 47.22%).
�
2
� 4
(
IV) (5.6 Â 10 g, 1.37 Â 10 mol) were blended slowly
throughout at 608C in a three-necked 100 ml ¯ask con-
nected with a re¯ux condenser and dropping funnel. Tri-
chlorosilane (10.1 g, 75.2 mmol) was dropped slowly to the
mixture. Heating at 1008C for 3 h gave the orange trans-
parent mixture. The product, trichloro[4,4-bis(tri¯uoro-
methyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl] silane (19.4 g),
was obtained as a colorless liquid by fractional distillation
under reduced pressure.
2.6. MM2 calculation
The molecular force ®eld calculations of various types of
trimethylalkylsilanes which were linear-type ¯uoroalkylsi-
lane, branched-type ¯uoroalkylsilane and branched-type
hydrocarbonaceous silane were performed by MM2 force
®eld (Allinger) method and Augmented MM2 method

T. Konakahara et al. / Journal of Fluorine Chemistry 101 (2000) 39±43
41
included in CAChe system (SONY Tektoronix, Tokyo,
Japan) using Macintosh computer.
The structure of synthesized poly¯uoroalkylsilane
(D3CL3, D3CL, D3Et3) were determined based on the data
of various spectra and elemental analysis. In the case of
D3CL3, the signals attributed to methylene chain appeared
3
. Results and discussion
1
19
at ꢀ ˆ 1.4 and 1.6±2.5 in H-NMR spectrum. In F-NMR
The synthetic procedures are shown in Fig. 1. Hydro-
spectrum the signals appeared at ꢀ ˆ 63.9 (CF bonded to
3
silylation of alkenes is conducted using various complexes
of transition metals as a catalyst [18]. In this study, hydrogen
hexachloroplatinate (IV) having high activity was used to
react branched-type poly¯uoroalkene with various silanes
under atmospheric pressure or in a sealed tube. Reaction
condition and products are shown in Table 1. In the case of
trichlorosilane the yield at atmospheric pressure was 74%
while the reaction in a sealed tube proceeded almost quan-
titatively in a 90% yield. In triethoxysilane also the yield
increased from 55% to 71% under pressure condition.
quaternary carbon), 80.8 (CF the end of the molecule),
3
107.3 and 123.1 (CF ). These signals slightly shifted to high
2
magnetic ®elds compared with the alkene as a starting
material and the integral ratio of the signals is 6 : 3 : 2 in
the decreasing order of magnetic ®led. D3CL3 and D3CL
were very sensitive against moisture in atmosphere and
decomposed immediately to produce hydrogen chloride.
As D3Et3 was relatively stable against hydrolysis, the mass
spectrum and elemental analysis supported its molecular
structure.
Fig. 1. Synthetic procedure of branched-polyfluoroalkylsilanes.
Table 1
The preparation conditions of hydrosilylation of 4,4-bis(trifluoromethyl)-5,5,6,6,7,7,7-heptafluoro-1-heptene with various silanes in the presence of H
PtCl
2 6
Silane
Molar ratio
D-2
Condition
Yield (%)
Method
Silane
H
2
PtCl
6
Temperature (8C)
Time (h)
3
3
3
3
3
HSiCl
HSiCl
3
1.0
1.0
1.0
1.0
1.0
1.4
1.6
1.1
1.3
1.3
2.6 Â 10�
100
100
80
3
3
3
3
3
74
90
81
55
71
Open
�
3
7.2 Â 10
Ampule
Open
�
HSi(CH
3
)
2
Cl
7.1 Â 10
�
HSi(OEt)
HSi(OEt)
3
1.3 Â 10
120
120
Open
4.3 Â 10�
Ampule
3

4
2
T. Konakahara et al. / Journal of Fluorine Chemistry 101 (2000) 39±43
Fig. 2. Molecular structures calculated by MM2. Linear-type fluoroalkylsilane (A), hydrocarbonaceous branched-type alkylsilane (B), branched-type
fluoroalkylsilane (C).
In general, mixed products of the Si±CHX±CH -type (the
3
bent structure at quaternary carbon. It seems that this
structure is caused by the steric repulsion between CF or
a-addition product) and Si±CH ±CH ±X-type (the b-addi-
2
2
2
tion product) are formed by the platinum-catalyzed addition
reaction of the compounds containing Si±H bonding with
CH and CF group having larger molecular volume than
3
2
CH group.
3
the compounds having a general formula CH =CH±X,
2
where the X group is not conjugated with C=C [19±21].
1
From H-NMR spectra of the trichloro[4,4-bis(tri¯uoro-
4. Conclusions
methyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl]silane, only three
kinds of proton signals such as Si±CH , Si±CH ±CH
2
Three kinds of branched-type poly¯uoroalkylsilanes
were synthesized by the hydrosilylation of the branched-
type poly¯uoroalkene with silanes and their molecular
structures were calculated by MM2 method. Three types
of branched-type poly¯uoroalkylsilanes, trichloro[4,4-bis-
(tri¯uoromethyl)-5, 5, 6, 6, 7, 7, 7-hepta¯uoroheptyl] silane
(D3CL3), monochlorodimethyl[4,4-bis(tri¯uoromethyl)-5,
5,6,6,7,7,7-hepta¯uoroheptyl]silane (D3CL), triethoxy[4,4-
bis(tri¯uoromethyl)-5,5,6,6,7,7,7-hepta¯uoroheptyl]silane
(D3Et3), could be synthesized using the hydrosilylation
reaction of the branched-type poly¯uoroalkene and corre-
sponding silanes in the presence of hydrogen hexachloro-
platinate (IV) as a catalyst. The hydrosilylation reaction of
4,4-bis(tri¯uoromethyl)-5, 5, 6, 6, 7, 7, 7-hepta¯uoro-1-hep-
tene with silanes produced only b-addition compounds
2
2
and Si±CH ±CH ±CH were observed and other proton
2
2
2
signals such as Si±CH and Si±CH±CH were not observed
3
at least. These results indicated that the hydrosilylation
reaction of trichlorosilane with 4,4-bis(tri¯uoromethyl)-
5,5,6,6,7,7,7-hepta¯uoro-1-heptene produced only b-addi-
tion compound highly regioselectively.
Molecular structures of the trimethylalkylsilanes ob-
tained by MM2 calculation are shown in Fig. 2. Linear-
type ¯uoroalkylsilane (A), CF (CF ) CH CH Si(CH ) and
3
2 5
2
2
3 3
branched-type hydrocarbonaceous silane (B), CH CH CH -
2
3
2
C(CH ) (CH ) Si(CH ) have a zigzag structure without
3
2
2 3
3 3
bending at the connection of CH and CF or CH and
2
2
2
quaternary carbon. On the contrary, branched-type ¯uoro-
alkylsilane, CF CF CF C(CF ) (CH ) Si(CH ) has the
3
2
2
3 2
2 3
3 3

T. Konakahara et al. / Journal of Fluorine Chemistry 101 (2000) 39±43
43
[
7] N. Yoshino, Y. Yamamoto, T. Teranaka, Chem. Lett. 1993 (1993)
21.
highly regioselectively. From the MM2 calculation, it was
found that the branched-poly¯uoroalkylsilane has a bent
structure at quaternary carbon. It seems that this structure is
8
[
[
8] N. Yoshino, A. Sasaki, T. Seto, J. Fluorine Chem. 71 (1995) 21.
9] I. Ojma, T. Fuchikami, M. Yatabe, Organometal. Chem. 260 (1984)
335.
caused by the repulsion between CF group and CF or CH
2
3
2
group differing from hydrocarbonaceous branched-type
alkylsilane.
[10] US Patent, USP 5 233 071 (1993).
[
[
[
11] Jpn. Patent, JP 53 144 525 (1978).
12] US Patent, USP 2 918 501 (1959).
13] N. Ishikawa, A. Nagashima, Nippon Kagaku Kaishi, 1975 (1975)
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