Phenyl(fluoro)chlorodisiloxanes

Article abstract of DOI:10.1134/S107036321002009X

Cohydrolysis of phenyltrichlorosilane with phenyl(fluoro)dichloro- and phenyl(difluoro)-chlorosilanes and thermolysis of the formed siloxanes leading to the formation of phenyl(difluoro)chlorosilane are studied. The scheme of thermal decomposition of disi

Full text of DOI:10.1134/S107036321002009X

ISSN 1070-3632, Russian Journal of General Chemistry, 2010, Vol. 80, No. 2, pp. 242–244. © Pleiades Publishing, Ltd., 2010.
Original Russian Text © S.V. Basenko, L.E. Zelenkov, M.G. Voronkov, A.I. Albanov, 2010, published in Zhurnal Obshchei Khimii, 2010, Vol. 80, No. 2,
pp. 217–219.
Phenyl(fluoro)chlorodisiloxanes
S. V. Basenko, L. E. Zelenkov, M. G. Voronkov, and A. I. Albanov
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
email: voronkov@irioch.irk.ru.
Received April 2, 2009
Abstract―Cohydrolysis of phenyltrichlorosilane with phenyl(fluoro)dichloro- and phenyl(difluoro)-
chlorosilanes and thermolysis of the formed siloxanes leading to the formation of phenyl(difluoro)chlorosilane
are studied. The scheme of thermal decomposition of disiloxanes possessing fluorine atoms in the 1,3 positions
is suggested. The scheme is based on the intermediate formation of an active four-membered cyclic complex
closed by the fluorine bridge between the silicon atoms. In agreement with the scheme, no thermolysis of 1,3-
diphenyl-1-fluoro-1,3,3-trichlorodisiloxane is observed under the studied conditions.
DOI: 10.1134/S107036321002009X
Reactions of cohydrolysis of hydrocarbylchloro-
silanes are well studied [1–6]. However, similar
processes with participation of hydrocarbylhalosilanes
containing two different halogen atoms at silicon have
not been studied, and the hydrolysis of organosilicon
monomers of this type (PhSiF2Cl, PhSiFCl2) is
mentioned only in one publication [7].
SiFPhO)2FSiPh were detected by the 19F and 29Si
NMR spectroscopy (see the table).
nPhSiF2Cl + mPhSiFCl2 + H2O
n = 0, m = 2
(PhSiFCl)2O + 2HCl,
(2)
(3)
(4)
III
n = 1, m = 1
n = 2, m = 0
PhSiF2OSiFClPh + 2HCl,
IV
To fill in this gap, we have studied cohydrolysis of
phenyl(fluoro)chlorosilanes PhSiF3–nCln (n = 1, 2) with
phenyltrichlorosilane (n = 3). Starting PhSiF2Cl (I) and
PhSiFCl2 (II) were synthesized by Eq. (1), by dispro-
portionation of equimolar mixture of phenyltri-
fluorosilane with phenyltrichlorosilane in the presence
of aluminum halides (AlX3, X = F, Cl, Br) (for X = Cl,
cf. [7]).
(PhSiF2)2O + 2HCl.
V
Cohydrolysis of PhSiF2Cl (I) and PhSiCl3 gives rise
to disiloxane V, as well as 1,3-diphenyltetra-chloro-
disiloxane (VI) and 1,3-diphenyl-1,1-difluoro-3,3-
dichlorodisiloxane (VII).
AlX3
nPhSiF2Cl + mPhSiCl3 + H2O
PhSiF3 + PhSiCl3
PhSiF Cl + PhSiFCl .
(1)
2 2
n = 2, m = 0
(PhSiF2)2O + 2HCl,
(5)
(6)
(7)
We have found that cohydrolysis of phenyl(fluoro)-
chlorosilane monomers I and II (molar ratio 1:1, 0.5–
1 h) leads to the earlier unknown 1,3–diphenyl-1,3-
difluoro-1,3-dichloro-disiloxane (III) and 1,3-di-
phenyl-1,1,3-trifluoro-3-chlorodisiloxane (IV), as well
as to the earlier synthesized 1,3-diphenyltetrafluoro-
disiloxane (V) [7, 8].
V
n = 0, m = 2
n = 1, m = 1
(PhSiCl2)2O + 2HCl,
VI
PhSiF2OSiCl2Ph + 2HCl.
VII
As the products of cohydrolysis of PhSiFCl2 and
PhSiCl3, 1,3-diphenyl-1,3-difluoro-1,3-dichlorodisil-
oxane (III), 1,3-diphenyltetrachlorodisiloxane (VI) and
1,3-diphenyl-1-fluoro-1,3,3-trichlorodisiloxane
were identified.
Increase in the reaction duration to 7–8 h was
followed by the formation, along with disiloxanes III–
V, of oligosiloxane structures among which PhSiF2
(OSiFPh)OF2SiPh, (PhSiF2OSiFPh)2O and (PhSiF2O·
(VIII)
242

243
PHENYL(FLUORO)CHLORODISILOXANES
nPhSiFCl2 + mPhSiCl3 + H2O
F
F
Ph
Si
X
Si
n = 2, m = 0
X
(PhSiFCl)2O + 2HCl,
(8)
(9)
O
Ph
III
Formation of phenyltrifluorosilane upon heating of
n = 0, m = 2
n = 1, m = 1
(PhSiCl2)2O + 2HCl,
disiloxane V was noticed earlier [7].
VI
Interestingly, an attempt to isolate disiloxanes III–
V, VII by vacuum distillation at 1 mm Hg leads to
their decomposition with the formation of phenyl-
trifluoro- and -(difluoro)chlorosilanes.
PhSiFClOSiCl2Ph + 2HCl.
(10)
VIII
The main product of hydrolysis of PhSiFCl2 (II) is
1,3-diphenyl-1,3-difluoro-1,3-dichloro-disiloxane III.
PhSiF2OSiFClPh → PhSiF3 + [PhClSi=O],
PhSiFClOSiFClPh → PhSiF2Cl + [PhClSi=O],
PhSiF2OSiF2Ph → PhSiF3 + [PhFSi=O],
PhSiF2OSiCl2Ph → PhSiF2Cl + [PhClSi=O].
(12)
(13)
(14)
(15)
In all of the above reactions the mixed phenyl-
(fluoro)chlorosilanes show enhanced reactivity mani-
fested in the predominant formation of symmetric
fluorocontaining disiloxanes.
Analysis of the 19F NMR spectra has shown the
absence of any cyclic structures or linear trisiloxanes
or higher homologs after short-term passing of
atmospheric air through the reaction mixture for 1–2 h,
as proved by the absence of signals at –131 to
–132 ppm in the studied spectra.
A tentative mechanism of reactions (12)–(14) may
include the formation of four-membered complex
containing the fluorine bridge between the two silicon
atom of the Si–O–Si group.
Decomposition of hexafluorodisiloxane [8] and
diphenyltetrafluorodisiloxane [9], apparently, follows
the same route.
Earlier we have shown that thermolysis of 1,3-di-
phenyltetrafluorodisiloxane (V) leads to cyclic and linear
phenylfluorosiloxanes and phenyltrifluorosilane [8].
SiF3OSiF3 → SiF4 + [F2Si=O].
(16)
Decomposition by scheme (15) is apparently
feasible due to the presence of strong acceptors at the
silicon atom (PhSiF2) which facilitate the intra-
molecular interaction.
(n + m)(PhF2Si)2O → (PhFSiO)n
+ PhF2SiO(PhFSiO)mSiF2Ph + (n + m)PhSiF3,
(11)
n = 3–4, m = 1–2.
19F, 29Si NMR parameters (CCl4, 20% v/v; 25°С)
δF, ppm
δSi, ppm
J
SiF, Hz
–
δF, ppm
δSi, ppm
J
SiF, Hz
Compound
PhSiF
–1.1
–18.8
–42.9
–72.8
–73.9
–74.0
–48.7
–48.6
–74.1
–
PhSiF
PhSiCl3
PhSiFCl2
–
–
–
–
–
–
–
–
–
–113.16
–124.25
–140.94
–136.56
–136.79
–121.00
–120.84
–137.00
–136.94
–136.94
–136.93
326.5
299.8
–
PhSiF2Cl
–
–
PhSiF3
267.0
–
–
PhSiF2–O–SiCl2Ph
PhSiF2–O–SiFClPh
PhSiFCl–O–SiFClPh
PhSiFCl–O–SiCl2Ph
PhSiF2–O–SiF2Ph
PhSiF2–O–SiFPh–O–F2SiPh
(PhSiF2–O–SiFPh–)2O
(PhSiF2–O–SiFPh–O–)2FSiPha
256.35
260.93
293.00
296.70
263.90
263.55
263.55
263.55
–
–28.6
–48.7
–48.7
–28.6
–74.1
–
–121.11
–121.03
–
291.40
293.00
–
–137.00
–132.90
–132.77
–132.75
263.90
–
–
–
–
–
–
–
a δF = –132.56 ppm.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 2 2010

244
BASENKO et al.
We did not observe thermal decomposition of 1,3-
Reactions of phenyl(difluoro)chlorosilane and
phenyl(fluoro)dichlorosilane with phenyltrichlorosilane
were performed similarly.
diphenyl-1-fluoro-1,3,3-trichlorodisiloxane (VIII) nor
of the synthesized by us 1,1,1-trimethyl-3-phenyl-3,3-
difluorodisiloxane under the studied conditions.
Thermolysis of phenyl(fluoro)chlorodisiloxanes was
performed in sealed ampules in the argon atmosphere
at 175–225ºC during 1.5–2 h. The formed phenyl-
trifluorosilane PhSiF3, bp 100–101.5ºC, nD 1.4110 (cf.
[11]) and phenyl(difluoro)chlorosilane PhSiF2Cl, bp
132–135ºC, nD 1.4579 (cf. [12–14]) were distilled off
and identified by the 19F and 29Si NMR (see the table).
The synthesized phenyl(fluoro)chlorodisiloxanes
were identified by 19F, 29Si NMR spectroscopy (see the
table).
In the IR spectra of compounds III–VIII the bands
in the region 1060–1100 cm–1 characteristic of the
Si–О–Si antisymmetric stretching vibrations, at 895,
920 cm–1 characteristic of the SiF2 and SiF fragments,
695–700, 715–720, 1110–1130, 1415, 1590 cm–1
(bending and stretching vibrations of the Si–C6H5
bond), and bands at 450–470 and 500–570 cm–1
belonging to the C–Cl bond vibrations are present.
The position of the absorption maxima corresponding
to vibrations of these bonds is constant in frequency
and independent on the substituents at the silicon atom
(chlorine or fluorine atoms) [10].
ACKNOWLEDGMENTS
This work was performed with the financial support
from the Council on Grants of the President of RF
(grant no. NSh-4575.2006.3) and Presidium of
Siberian Branch of the Russian Academy of Sciences
(complex integration project no. 4.17).
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EXPERIMENTAL
19F and 29Si NMR spectra were registered on a
Bruker DPX 400 instrument with working frequencies
376.47 (19F) and 79.49 MHz (29Si) in CCl4, internal
reference for 29Si, TMS, for 19F, CFCl3. IR spectra
were recorded on a Specord IR 75 spectrometer in the
range of 400–4000 cm–1 from thin film. Electron
ionization mass spectra were taken on a SHIMADZU
GCMS-QP5050A mass spectrometer, injector tem-
perature 200–250°C, gas-carrier helium, detector
temperature 200°C, quadruple mass analyzer, energy
of electrons 70 eV.
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Mixed phenyl(fluoro)chlorosilanes PhSiClnF3–n with
n = 1, 2 were prepared by disproportionation of PhSiF3
with PhSiCl3 in the presence of aluminum halides
(cf. [7]). PhSiFCl2: bp 163–166ºC, nD 1.4854 [cf. 13–15].
Mass spectrum, m/z (I, %) ion: 194 (100) [M]•+; 175
(1) [M – F]+; 159 (92) [M – Cl]+; 158 (23); 133 (3);
131 (6); 117 (41) [M – Ph]+; 112 (30) [PhCl]•+; 107
(7); 82 (9) [SiClF]+; 77 (83) [Ph]+; 76 (26); 75 (16); 74
(25); 63 (9) [SiCl]+; 51 (99); 50 (88); 47 (72) [SiF]+;
39 (20); 38 (17).
Mild cohydrolysis of phenyl(fluoro)chlorosilanes
(I, II). Through the mixture of 1.80 g (0.01 mol) of
phenyl(difluoro)chlorosilane and 1.95 g (0.01 mol) of
phenyl(fluoro)dichlorosilane atmospheric air was
bubbled during 30 min and the mixture was analyzed
by the 19F and 29Si NMR method (see the table).
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 80 No. 2 2010