Improved synthesis of HOPh2Si-SiPh2OH and crystal structure analyses of HOPh2Si-SiPh2OH and HOPh2Si-SiPh2-O-Ph2Si-SiPh2 OH·1/2C6H6

Article abstract of DOI:10.1515/znb-2002-0703

1,1,2,2-Tetraphenyldisilane-1,2-diol (3) was prepared in a two-step synthesis, starting from 1,2-bis(diethylamino)-1,1,2,2-tetraphenyldisilane (1). Treatment of 1 with acetyl chloride yielded 1,2-dichloro-1,1,2,2-tetraphenyldisilane (2), which upon hydrol

Full text of DOI:10.1515/znb-2002-0703

Improved Synthesis of HOPh2Si-SiPh2OH and Crystal Structure Analyses
of HOPh2Si-SiPh2OH and HOPh2Si-SiPh2-O-Ph2Si-SiPh2OH·1/2C6H6
Reinhold Tacke, Joachim Heermann, Martin Penka, Ingo Richter, and Brigitte Wagner
Institut fu¨r Anorganische Chemie, Universita¨t Wu¨rzburg,
Am Hubland, D-97074 Wu¨rzburg, Germany
Reprint requests to Prof. Dr. R. Tacke. E-mail: r.tacke@mail.uni-wuerzburg.de
Z. Naturforsch. 57 b, 731–735 (2002); received March 11, 2002
Disilanes, Silanols, Siloxanes
1,1,2,2-Tetraphenyldisilane-1,2-diol (3) was prepared in a two-step synthesis, starting from
1,2-bis(diethylamino)-1,1,2,2-tetraphenyldisilane (1). Treatment of 1 with acetyl chloride
yielded 1,2-dichloro-1,1,2,2-tetraphenyldisilane (2), which upon hydrolysis gave 3 (total yield
83%). Compounds 2 and 3 were characterized by elemental analyses (C, H) and solution
NMR experiments (1H, 13C, 29Si; CDCl3). In addition, compound 1 and its condensation
product, 1,5-dihydroxy-1,1,2,2,4,4,5,5-octaphenyl-3-oxa-1,2,4,5-tetrasilapentane(4; studied as
the hemibenzene solvate 4 1/2C6H6), were structurally characterized by single-crystal X-ray
diffraction.
Introduction
1,1,2,2-Tetraphenyldisilane-1,2-diol (3) is a ver-
satile difunctional building block for the synthe-
sis of siloxane systems with Si-Si bonds (for a re-
cent example, see ref. [1]). In 1961 Winkler and
Gilman reported on the first synthesis of compound
3, starting from chlorodiphenylsilane and using a
coupling reaction with magnesium to form the Si-Si
bond [Ph2Si(H)Cl
HPh2Si-SiPh2H
ClPh2Si-
SiPh2Cl HOPh2Si-SiPh2OH] [2]. As this syn-
thetic method is characterized by unsatisfactory
yields and limited reliability, we have worked out
an alternative approach for the synthesis of 3, us-
ing a method for the Si-Si bond formation devel-
oped by Tamao et al. [3]. We report here on an
improved and reliable synthesis of compound 3 and
the crystal structure analyses of 3 and its conden-
sation product 1,5-dihydroxy-1,1,2,2,4,4,5,5-octa-
phenyl-3-oxa-1,2,4,5-tetrasilapentane (4; studied as
the hemibenzene solvate 4 1/2C6H6).
Scheme 1.
from 1,2-bis(diethylamino)-1,1,2,2-tetraphenyldi-
silane (1) [3, 4]. Thus, treatment of 1 with acetyl
chloride in dichloromethane afforded 1,2-dichloro-
1,1,2,2-tetraphenyldisilane (2) (yield 89%), which
upon hydrolysis in a mixture of dichloromethane,
diethyl ether, water, and ammonium carbonate gave
the disilanediol 3 (yield 93%; total yield 83%).
Compounds 2 and 3 were isolated as crystalline
solids, and their identities were established by el-
emental analyses (C, H) and solution NMR stud-
ies (1H, 13C, 29Si; CDCl3). In addition, 3 and its
condensation product 4 (studied as the hemiben-
zene solvate 4 1/2C6H6) were structurally charac-
terized by single-crystal X-ray diffraction. Com-
pound 4 1/2C6H6 [2] was isolated in minor amounts
as a by-product in the crystallization of 3.
Results and Discussion
The title compound 3 was prepared accord-
ing to Scheme 1 in a two-step synthesis, starting
c
¨
¨
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R. Tacke et al. · Improved Synthesis of HOPh2Si-SiPh2OH
Table 1. Crystal data and experimental pa-
3
4 1/2C6H6
rameters for the crystal structure analyses of
3 and 4 1/2C6H6.
Empirical formula
Formula mass [g mol
Collection T [K]
(Mo-K ) [A]
Crystal system
C24H22O2Si2 C51H45O3Si4
1
]
398.60
173(2)
0.71073
triclinic
818.23
173(2)
0.71073
monoclinic
C2/c (15)
23.502(5)
16.755(3)
24.508(5)
90
[a] S = Σ [w(Fo2 – Fc )2] (n – p) 0 5; n = no.
2
of reflections; p = no. of parameters; [b]
w
=
1
˚
2(Fo ) + (aP)2 + bP, with P = [max(Fo ,0)
2
2
2
[c]
¯
+ 2Fc ]/3;
R1 = Σ |Fo| – |Fc| Σ |Fo|;
Space group (no.)
P1 (2)
2 2 0 5
[d] wR2 = Σ [w(Fo2 – Fc )2]/Σ [w(Fo )2]
.
˚
a [A]
13.229(3)
14.664(3)
19.394(4)
103.96(3)
100.83(3)
113.64(3)
3168.9(11)
6
˚
b [A]
˚
c [A]
[ ]
[ ]
[ ]
110.99(3)
90
3
˚
V [A ]
9011(3)
8
Z
3
D (calcd.) [g cm
]
1.253
1.206
1
[mm
F(000)
]
0.185
0.173
1260
3448
Crystal dimensions [mm]
2 Range [deg]
Index ranges
0.2 0.2 0.2 0.4 0.3 0.3
5.74-52.86
4.16-46.54
–16
h
k
l
16, –26
17, –18
24 –27
h
k
l
26,
18,
27
–18
–24
No. of collected reflections
46146
35777
No. of independent reflections 12536
6457
0.0759
6457
4
536
1.009
Rint
0.0387
12536
6
775
0.888
No. of reflections used
No. of restraints
No. of parameters
S[a]
Weight parameters a/b[b]
R1[c] [I > 2 (I)]
wR2[d] (all data)
0.0442/0.0000 0.0554/0.5681
0.0419
0.0893
0.0360
0.0934
Max./min. residual electron
density [e A
+0.319/–0.290 +0.285/–0.185
3
˚
]
Compound 3 crystallizes in the space group crystallographically different molecules are char-
¯
P1, with three molecules in the asymmetric unit acterized by gauche arrangements, with O-Si-Si-
(molecules 3A, 3B, and 3C). Compound 4 1/2C6H6 O dihedral angles amounting to –68.56(10) (3A),
crystallizes in the space group C2/c, with one half –70.56(11) (3B), and –66.71(11) (3C). The three
each of molecules 4A and 4B and one half of a ben- conformations differ mainly in the arrangement of
zene molecule in the asymmetric unit. The crystal their phenyl groups (different degrees of torsion
data and the experimental parameters used for the around the respective Si-C bonds).
crystal structure analyses of 3 and 4 1/2C6H6 are
summarized in Table 1. The structures of molecules
3A, 3B, 3C, 4A, and 4B are depicted in Figures 1-4.
The crystal structure of 3 is characterized by a
complex one-dimensional hydrogen bonding sys-
tem with six intermolecular O-H O interactions
The Si-Si (Si-O) distances of 3 are in the along the base vector [0 0 1] (Table 2, Fig. 5). All
˚
range 2.3617(9) - 2.3790(11) A [1.6482(19) - six OH groups are involved as donor functions, and
˚
1.6584(17) A], and the Si-C bond lengths amount the oxygen atoms O1, O2 (2-fold), O3, O4, and O6
to 1.864(2) - 1.8808(19) A. All silicon atoms are act as acceptor atoms. These hydrogen bonds lead to
˚
tetrahedrally coordinated, with bond angles at the an infinite tube-like arrangement of the molecules
silicon atoms in the range 101.42(8) - 117.53(7)
in the crystal, with the hydrophilic SiOH groups in-
(for crystal structures of other disilane-1,2-diols, see side and the hydrophobic phenyl groups outside the
refs. [5] and [6]). The conformations of the three tube.
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R. Tacke et al. · Improved Synthesis of HOPh2Si-SiPh2OH
733
Fig. 1. Structure of molecule 3A in the crystal of 3. Fig. 3. Structure of molecule 3C in the crystal of 3. Se-
˚
˚
Selected distances [A] and angles [ ] (standard de- lected distances [A] and angles [ ] (standard deviations in
viations in parentheses): Si1-Si2 2.3708(10), Si1-O1 parentheses): Si5-Si6 2.3617(9), Si5-O5 1.6545(15), Si5-
1.6584(17), Si1-C1 1.869(3), Si1-C7 1.8808(19), Si2- C49 1.864(2), Si5-C55 1.869(2), Si6-O6 1.6482(19), Si6-
O2 1.6544(15), Si2-C13 1.871(3), Si2-C19 1.871(2); C61 1.877(2), Si6-C67 1.873(2); Si6-Si5-O5 109.64(7),
Si2-Si1-O1 110.64(6), Si2-Si1-C1 111.89(7), Si2-Si1-C7 Si6-Si5-C49 117.24(7), Si6-Si5-C55 101.42(8), O5-
110.39(7), O1-Si1-C1 106.78(10), O1-Si1-C7 110.49(9), Si5-C49 108.42(9), O5-Si5-C55 111.23(9), C49-
C1-Si1-C7 106.51(10), Si1-Si2-O2 110.56(7), Si1- Si5-C55 108.73(10), Si5-Si6-O6 114.80(7), Si5-
Si2-C13 112.26(7), Si1-Si2-C19 106.89(7), O2-Si2- Si6-C61 107.61(7), Si5-Si6-C67 103.77(7), O6-Si6-
C13 109.15(9), O2-Si2-C19 107.73(9), C13-Si2-C19 C61 108.36(9), O6-Si6-C67 109.15(10), C61-Si6-C67
110.13(10).
113.23(10).
drally coordinated, with bond angles at the sil-
icon atoms in the range 103.62(6) - 116.31(7)
(for the crystal structure of a related cyclic con-
densation product, see ref. [7]). The conforma-
tions of the two crystallographically different
molecules can each be described as eight-mem-
bered rings, including one of the two OH hydrogen
atoms.
Attempts to localize the OH hydrogen atoms
in the difference Fourier synthesis failed. Thus,
the O-H distances were constrained in the refine-
ment to result in a chemically acceptable hydrogen-
bonding situation. Due to symmetry requirements
of the unit cell, the OH hydrogen atoms are disor-
deredontwoequallyoccupied positions. Thehydro-
gen-bonding system depicted in Fig. 4 represents
one of the two possible arrangements (intramolecu-
lar O2A-H2OD O2 and O4-H4OB O4A interac-
tions as well as intermolecular O2-H2OA O4 and
O4A-H4OC O2A interactions; second arrange-
ment: intramolecular O2-H2OB O2A and O4A-
H4OD O4 interactions as well as intermolecu-
lar O2A-H2OC O4A and O4-H4OA O2 interac-
tions). As a result, this hydrogen-bonding system
leads to the formation of dimers of 4A and 4B in the
crystal of 4 1/2C6H6.
Fig. 2. Structure of molecule 3B in the crystal of 3.
˚
Selected distances [A] and angles [ ] (standard de-
viations in parentheses): Si3-Si4 2.3790(11), Si3-O3
1.6494(18), Si3-C25 1.877(2), Si3-C31 1.879(2), Si4-
O4 1.6526(17), Si4-C37 1.876(2), Si4-C43 1.880(2);
Si4-Si3-O3 108.58(7), Si4-Si3-C25 104.61(7), Si4-
Si3-C31 117.53(7), O3-Si3-C25 108.57(10), O3-
Si3-C31 108.58(9), C25-Si3-C31 108.64(10), Si3-
Si4-O4 114.23(6), Si3-Si4-C37 111.57(7), Si3-Si4-
C43 106.45(7), O4-Si4-C37 106.23(9), O4-Si4-C43
108.85(10), C37-Si4-C43 109.44(9).
The Si-Si (Si-O) distances of 4 1/2C6H6 are in
˚
the range 2.3510(9) - 2.3527(9) A [1.6277(7) -
˚
1.6502(15) A], and the Si-C bond lengths amount to
1.867(2) - 1.873(2) A. All silicon atoms are tetrahe-
˚
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734
R. Tacke et al. · Improved Synthesis of HOPh2Si-SiPh2OH
Fig. 4. Structures of molecules 4A and 4B in the crystal of 4 1/2C6H6 (phenyl groups represented as stick models
˚
for clarity). Selected distances [A] and angles [ ] (standard deviations in parentheses) for 4A: Si1-Si2 2.3510(9),
Si1-O1 1.6277(7), Si1-C1 1.867(2), Si1-C7 1.871(2), Si2-O2 1.6492(16), Si2-C13 1.869(2), Si2-C19 1.871(2); Si2-
Si1-O1 105.03(6), Si2-Si1-C1 116.31(7), Si2-Si1-C7 111.98(7), O1-Si1-C1 105.17(10), O1-Si1-C7 110.09(8), C1-
Si1-C7 107.92(9), Si1-Si2-O2 104.23(6), Si1-Si2-C13 111.37(7), Si1-Si2-C19 115.60(7), O2-Si2-C13 109.43(10),
O2-Si2-C19 108.96(9), C13-Si2-C19 107.14(9), Si1-O1-Si1A 161.50(14). Data for 4B: Si3-Si4 2.3527(9), Si3-O3
1.6307(8), Si3-C25 1.873(2), Si3-C31 1.871(2), Si4-O4 1.6502(15), Si4-C37 1.867(2), Si4-C43 1.871(2); Si4-Si3-
O3 108.25(7), Si4-Si3-C25 107.87(6), Si4-Si3-C31 112.40(7), O3-Si3-C25 108.07(7), O3-Si3-C31 108.39(9), C25-
Si3-C31 111.71(9), Si3-Si4-O4 103.62(6), Si3-Si4-C37 113.85(7), Si3-Si4-C43 112.79(7), O4-Si4-C37 106.85(9),
O4-Si4-C43 109.10(9), C37-Si4-C43 110.17(10), Si3-O3-Si3A 175.70(14).
Table 2. Hydrogen-bonding geometries in the crystal of 3
[a]
˚
(distances [A] and angles [ ]) .
D-H
A
D
A
D-H
H
A
D-H A
O1-H1O O4 2.676(3) 0.83(3)
O2-H2O O2 2.737(3) 0.80(3)
O3-H3O O6 2.699(2) 0.83(2)
1.84(3)
1.97(3)
1.92(2)
179(3)
163(3)
156(2)
O4-H4O O2 2.764(2) 0.809(18) 1.956(18) 177(3)
O5-H5O O3 2.736(2) 0.82(3)
O6-H6O O1 2.735(2) 0.83(3)
1.93(2)
1.91(3)
168(3)
170(3)
[a] Data calculated by using the program PLATON [8].
Experimental Section
General procedures. All syntheses were carried out
under dry nitrogen. The organic solvents used were dried
and purified according to standard procedures and stored
under nitrogen. Melting points were determined with a
Bu¨chi Melting Point B-540 apparatus using samples in
Fig. 5. Infinite tube-like arrangement of molecules 3A, 3B,
and 3C in the crystal of 3 (projection along [0 0 1]), with
the hydrophilic SiOH groups inside and the hydrophobic
phenyl groups outside the tube. The phenyl groups are
represented as stick models for clarity.
1
sealed capillaries. The H, 13C, and 29Si NMR spectra
were recorded at 22 C on a Bruker DRX-300 NMR
spectrometer (1H, 300.1 MHz; 13C, 75.5 MHz; 29Si,
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R. Tacke et al. · Improved Synthesis of HOPh2Si-SiPh2OH
735
59.6 MHz). CDCl3 was used as solvent. Chemical shifts 7.40 and 7.45 - 7.54 (m, 20 H, SiPh). – 13
C
1H NMR:
(ppm) were determined relative to internal CHCl3 (1H, =
= 127.8 (C-2/C-6 or C-3/C-5, SiPh), 129.7 (C-4, SiPh),
7.24), internal CDCl3 (13C, = 77.0), or external TMS 134.2 (C-1, SiPh), 136.2 (C-2/C-6 or C-3/C-5, SiPh). –
(29Si, = 0).
29Si 1H NMR: = –10.4. – C24H22O2Si2 (398.6): calcd.
C 72.32, H 5.56; found C 72.2, H 5.6.
1,2-Bis(diethylamino)-1,1,2,2-tetraphenyldisilane (1)
This compound was synthesized according to ref. [3].
1,5-Dihydroxy-1,1,2,2,4,4,5,5-octaphenyl-3-oxa-
1,2,4,5-tetrasilapentane-Hemibenzene (4 1/2C6H6)
1,2-Dichloro-1,1,2,2-tetraphenyldisilane (2)
Compound 4 1/2C6H6 wasformed in minor amounts as
aby-productin thecrystallization of 3. A procedurefor the
synthesis of 4 1/2C6H6 has been reported elsewhere [2].
Acetyl chloride (1.60 g, 20.4 mmol) was added
to a stirred solution of 1 (5.00 g, 9.83 mmol) in
dichloromethane (40 ml) at 0 C and the mixture then
stirred for 1 d at r. t. The solvent was removed under
reduced pressure and the resulting solid recrystallized
Crystal structure analyses of 3 and 4 1/2C6H6
Suitable single crystals of 3 and 4 1/2C6H6 were ob-
from toluene / petroleum ether (40 - 60 C) [1:1 (v/v)] to tained by crystallization of 3 from benzene/petroleum
give 3.81 g (8.75 mmol) of a colorless crystalline prod- ether (60 - 70 C) (see preparation). The crystals were
1
uct (yield 89%). – M. p. 106 - 109 C. – H NMR:
=
mounted in inert oil (perfluoroalkyl ether, ABCR) on a
7.26 - 7.69 (m, 20 H, SiPh). – 13C 1H NMR: = 128.2 glass fiber and then transferred to the cold nitrogen gas
(C-2/C-6 or C-3/C-5, SiPh), 130.8 (C-4, SiPh), 132.2 (C- stream of the diffractometer (Stoe IPDS; graphite-mono-
1, SiPh), 135.0 (C-2/C-6 or C-3/C-5, SiPh). – 29Si 1H
chromated Mo-K radiation, = 0.71073 A). The struc-
˚
NMR: = –4.6. – C24H20Cl2Si2 (435.5): calcd. C 66.19, tures were solved by direct methods (SHELXS-97) [9]
H 4.63; found C 66.2, H 4.7.
and refined by full-matrix least-squares on F2 with all
unique reflections (SHELXL-97) [10]. For the CH hy-
drogen atoms of 3 and 4 1/2C6H6, a riding model was
employed. The OH hydrogen atoms of 3 were localized in
the Fourier synthesis and refined freely. The OH hydrogen
atoms of 4 1/2C6H6 were placed on ideal positions and re-
fined using distance restraints. Crystallographic data (ex-
cluding structure factors) have been deposited with the
Cambridge Crystallographic Data Centre as supplemen-
tary publication no CCDC-181214 (3) and CCDC-181215
(4 1/2C6H6). Copies of the data can be obtained free of
charge on application to CCDC, 12 Union Road, Cam-
bridge CB2 1EZ, UK [Fax: (+44)1223-336-033; e-mail:
deposit@ccdc.cam.ac.uk].
1,1,2,2-Tetraphenyldisilane-1,2-diol (3)
A solution of 2 (2.00g, 4.59 mmol) in dichloromethane
(7 ml) was added dropwise at 0 C to a stirred mixture
of water (17 ml), diethyl ether (5 ml), and ammonium
carbonate (618 mg, 6.43 mmol). Stirring was continued
for 1 h at the same temperature and the aqueous phase
then saturated with sodium chloride. The two phases were
separated, and the aqueous layer was extracted with di-
ethyl ether (2
20 ml). The combined organic phases
were dried over anhydroussodium sulfate, and the solvent
was removed under reduced pressure. The resulting crude
product was recrystallized from benzene / petroleum ether
(60 - 70 C) [1:1 (v/v); cooling of a boiling saturated so-
lution to room temperature] to give 1.70 g (4.26 mmol) of
a colorless crystalline product (yield 93%). – M. p. 138 -
140 C. – 1H NMR: = 2.65 (br. s, 2 H, SiOH), 7.21 -
Acknowledgments
This work was supported by the Deutsche Forschungs-
gemeinschaft and the Fonds der Chemischen Industrie.
[1] R. Tacke, C. Burschka, J. Heermann, I. Richter, B. Wagner,
R. Willeke, Eur. J. Inorg. Chem. 2211 (2001)
[2] H. J. S. Winkler, H. Gilman, J. Org. Chem. 26, 1265 (1961).
[3] Synthesis of 1: K. Tamao, A. Kawachi, Y. Nakagawa, Y. Ito,
J. Organomet. Chem. 473, 29 (1994).
[4] Crystal structure analysis of 1: F. Huppmann, M. Nolte-
meyer, A. Meller, J. Organomet. Chem. 483, 217
(1994).
[5] Crystal structure analysis of HO(t-Bu)2Si-Si(t-Bu)2OH:
R. West, E. K. Pham, J. Organomet. Chem. 403, 43 (1991).
[6] Crystal structure analysis of HOMe2Si-SiMe2OH: M. Pras-
se, H. Reinke, C. Wendler, H. Kelling, J. Organomet. Chem.
577, 342 (1999).
[7] Crystal structure analysis of the all-trans-isomer of 2,3,5,
6-tetramethyl-2,3,5,6-tetraphenyl-1,4-dioxa-2,3,5,6-tetra-
silacyclohexane: V. V. Semenov, E. Y. Ladilina, Y. A.
Kurskii, S. Y. Khorshev, N. P. Makarenko, G. A. Dom-
rachev, L. N. Zakharov, G. K. Fukin, Y. T. Struchkov,
Russ. Chem. Bull. 45, 2420 (1996).
[8] The hydrogen-bonding system was analyzed by using the
program PLATON: A. L. Spek, PLATON, University of
Utrecht, The Netherlands (1998).
[9] G. M. Sheldrick, SHELXS-97, University of Go¨ttingen,
Germany (1997); G. M. Sheldrick, Acta Crystallogr. A
46, 467 (1990).
[10] G. M. Sheldrick, SHELXL-97, University of Go¨ttingen,
Germany (1997).
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