((ButO)3SiO-), consistent with the presence of four non-equivalent
Si atoms. Likewise, the 13C spectrum showed peaks at d = 1.493
(1-methyl), 4.526 (3-methyl), 31.730 (CH3 in tert-butyl), 72.780 (t-
C), and 128.031, 130.383, 134.688 and 135.501 ppm (phenyl).
The terminal chloride in IV can be utilized to add another
siloxane unit to the tetrasiloxane to form pentasiloxane V by
reaction with VII, as in Eqn. 2. After purification, V was obtained
1
with 89.8% yield. Its H NMR spectrum (spectrum 1d) showed
resonances at d = 1.404 ppm (tert-butyl), 0.289 ppm (2-methyl),
0.365 ppm (4-methyl), ~ 7.230 ppm (H3 and H4 of 1- and
3-phenyl), ~ 7.730 ppm (H2 of 3-phenyl) and ~ 7.870 ppm (H2 of
1-phenyl) with area ratios of 27.0:5.9:6.1:11.7:4.1:4.0 (theoretical
ratio being 27:6:6:12:4:4). Its 29Si NMR spectrum (spectrum 2d)
showed resonances that can be assigned to the fifth (d = 299.86
ppm, first being SiOH), fourth (219.86 ppm), third (247.32 ppm),
second (218.10 ppm) and first Si atom (238.04 ppm). Its 13C
spectrum showed resonances at d = 1.530 (2-methyl), 1.627
(4-methyl) 31.710 (CH3 in tert-butyl), 72.162 (t-C), one group at
127.959, 130.144, 134.644, 135.514 and another at 128.083,
130.388, 134.760, and 136.253 ppm for the 1- and 3-phenyl groups,
respectively.
Fig. 1 1H NMR spectra of toluene-d8 solutions of: a, (ButO)3SiOSi(CH3)2Cl
II; b, (ButO)3SiOSi(CH3)2OSiPh2OH III; c, (ButO)3SiOSi(CH3)2OSi-
Ph2OSi(CH3)2Cl IV; and d, (ButO)3SiOSi(CH3)2OSiPh2OSi(CH3)2OSi-
Ph2OH V. Peaks at d = 7.025, 7.062, and 7.145 are due to toluene-h1
impurity.
Longer siloxane chains can be synthesized by repeating the
procedure described here. Since the siloxane units are added one at
a time, this method offers the possibility of introducing specific
alkyl side chains at specific locations by using the appropriate chain
growth agents analogous to VI and VII. Additional flexibility in
choice of chain growth agents is offered by the fact that the chloride
ligands in a living chain can be converted easily to a hydroxyl
ligand by hydrolysis. Similarly, reacting an active chain with
trichlorosilane or silanetriol can lead to branching at specific
locations. The chain can also be terminated by reacting an active
chain with monochlorosilane or silanol, such that the resulting
chain does not possess any reactive ligands. These possibilities will
be tested in the future.
This work was supported by the Department of Energy,
Department of Science, Basic Energy Sciences.
Fig. 2 29Si NMR spectra of toluene-d8 solutions of: a, (ButO)3SiO-
Si(CH3)2Cl II; b, (ButO)3SiOSi(CH3)2OSiPh2OH III; c, (ButO)3SiO-
Si(CH3)2OSiPh2OSi(CH3)2Cl IV; and d, (ButO)3SiOSi(CH3)2OSiPh2O-
Si(CH3)2OSiPh2OH V.
Notes and references
1 E.g. V. Bazant and J. Benes, Collect. Czech. Chem. Commun., 1959, 24,
624; V. Bazant and J. Benes, Chem. Abstr., 1959, 53, 28792.
2 H. J. Fletcher and G. L. Constan, 1959, US patent 2890234, CAN
1959:54:11237.
3 H. A. Clark and L. A. Haluska, 1959, US Patent 2877256, CAN
1959:53:89244.
4 N. N. Makarova, B. D. Lavrukhin, G. N. Turkel’taub, N. N. Kuz’min, I.
M. Petrova and E. V. Matukhina, Izv. Akad. Nauk SSSR, Ser. Khim.
1989, (6), 1351, CAN 112:77526.
5 O. Graalmann, U. Klingebiel, W. Clegg, M. Haase and G. M. Sheldrick,
Chem. Ber., 1984, 117(9), 2988.
6 J. Chrusciel and Z. Lasocki, Pol. J. Chem., 1983, 57(1–3), 121–8 CAN
101:72791.
7 E. P. Lebedev, S. S. Lukashenko, V. A. Baburina, I. E. Saratov and V.
O. Reikhsfel’d, Z. Obshch. Khim., 1978, 48(8), 1757–62 CAN
89:180089.
8 V. A. Achelashvili, O. V. Mukbaniani, L. M. Khananashvili, V. S.
Kikoladze and V. G. Tsitsishvili, Zh. Obshch. Khim., 1986, 56(7),
1530–5 CAN 107:59082.
9 E. S. Khynku, G. V. Kotrelev, O. B. Gorbatsevich, V. S. Svistunov, T.
V. Strelkova, Y. E. Ovchinnikov and Y. T. Struchkov, Dokl. Akad. Nauk
SSSR, 1991, 320(3), 648–52 CAN 116:83762.
peaks around 7.243 ppm (H3 and H4 of phenyl), and around 7.888
ppm (H2 of phenyl) with the intensity ratios of 27:6:6.3:4, close to
the theoretical ratios of 27:6:6:4. There was a peak at d = 4.808
ppm due to hydroxyl. Compared with the 1H NMR of II, III
showed the new peaks from the phenyl groups and shifting of the
methyl peaks to d = 0.357 ppm from d = 0.503 ppm in the
disiloxane. There were three silicon resonances for III at d =
2100.260 (assigned to (ButO)3SiO-), 218.250 ppm (-OSi-
(CH3)2O-) and 237.178 ppm (-OSiPh2OH) (spectrum 2b), indicat-
ing the presence of Si in three different environment. The 13C
spectrum showed peaks at d = 1.277 (Si–CH3), 31.471 (CH3 in
tert-butyl), 73.727 (t-C), and a group at 127.872, 130.073, 134.673,
and 136.268 ppm due to the phenyl group.
Further chain lengthening to form the tetrasiloxane IV was
achieved by applying reaction 1 to III, since III contains a hydroxyl
group that can react with VI. Thus, IV could be synthesized at
95.5% yield by reacting III with excess VI in the presence of
1
pyridine, followed by purification. H NMR of IV (spectrum 1c)
showed peaks at d = 1.406 ppm (tert-butyl), 0.389 ppm (3-methyl),
0.410 ppm (1-methyl), ~ 7.260 ppm (H3 + H4 of phenyl), ~ 7.870
ppm (H2 of phenyl) with area ratios of 27.0:5.9:5.7:6.3:4.2
(theoretical ratios are 27:6:6:6:4). 29Si NMR (spectrum 2c) showed
peaks at d = 5.441 ppm (OSi(CH3)2Cl), 219.510 ppm (-OSi-
(CH3)2O-), 246.273 ppm (-OSiPh2O-), and 2100.353 ppm
10 N. N. Korneev, G. I. Shcherbakova, V. S. Kolesov, G. B. Sakhar-
ovskaya, E. I. Shevchenko, V. S. Nikitin, L. N. Bazhenova and I. S.
Nikishina, Zh. Obshch. Khim., 1987, 57(2), 330–5CAN 108:112535.
11 M. Akkurt, T. R. Koek, P. Faleschini, L. Randaccio, H. Puff and W.
Schuh, J. Organomet.. Chem., 1994, 470, 59–66 CAN 121:109232.
C h e m . C o m m u n . , 2 0 0 4 , 2 0 6 – 2 0 7
207