Synthesis and mesomorphic properties of cis-penta[(phenyl)(trimethylsiloxy) ]cyclopentasiloxane

Article abstract of DOI:10.1007/s11172-007-0214-x

New stereoregular cis-penta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane cis-[PhSi(O)(OSiMe₃)]₅ was synthesized. According to the data from DSC, X-ray diffraction, and polarization microscopy, the noncrystallizable cyclopentasiloxane

Full text of DOI:10.1007/s11172-007-0214-x

Russian Chemical Bulletin, International Edition, Vol. 56, No. 7, pp. 1402—1407, July, 2007
1402
Synthesis and mesomorphic properties of
cisꢀpenta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
Yu. A. Molodtsova,a O. I. Shchegolikhina,a A. S. Peregudov,a M. I. Buzin,a and E. V. Matukhinab
aA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
28 ul. Vavilova, 119991 Moscow, Russian Federation.
Fax: +7 (495) 135 5085. Eꢀmail: olga@ineos.ac.ru
bMoscow Pedagogical State University,
1 ul. Malaya Pirogovskaya, 119882 Moscow, Russian Federation
New
stereoregular
cisꢀpenta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
cisꢀ[PhSi(O)(OSiMe3)]5 was synthesized. According to the data from DSC, Xꢀray diffraction,
and polarization microscopy, the noncrystallizable cyclopentasiloxane exists in the mesomorꢀ
phic state throughout the temperature range below the temperature of destruction and is
transformed into mesomorphic glass below the glass transition temperature. This compound
possesses the polymesomorphic properties and forms two mesomorphic modifications. The
type of mesomorphic ordering for these modifications was determined.
Key words: polyhedral metallasiloxanes, trimethylsilylation, stereoregular organoꢀ
cyclosiloxanes, mesomorphic state, polymesomorphism, phase transitions, plastic crystals,
differential scanning calorimetry, Xꢀray diffraction study, polarization microscopy
.
Earlier,1—11 we have demonstrated that polyhedral
Compounds D6 are prone to polymesomorphism and form
two mesomorphic modifications, which differ in the diꢀ
mensionality of the order and the type of ordering. Immeꢀ
diately after melting of the crystalline phase, cyclohexaꢀ
siloxanes form a 2Dꢀtype columnar hexagonal mesophase
(lowꢀtemperature (LT) mesophase). The rise of the temꢀ
perature causes the polymesomorphic transition of the
LT mesophase to the highꢀtemperature (HT) mesophase.
The HT mesophase is characterized by the higher order
(3D), and its structural organization is typical of plastic
crystals. The aboveꢀmentioned features of the mesomorꢀ
phism of these cyclohexasiloxanes are observed regardless
of the nature of the side groups R. A change in the chemiꢀ
cal structure of these groups in compounds D4 and D6 has
no effect on the structural organization of the mesoꢀ
phase.3,4,6,7 At the same time, the temperature range of
the existence of 3D and 2D mesophases and the unit cell
parameters of plastic crystals and columnar mesophases
substantially depend on the nature of the side substituents.7
Therefore, for a series of compounds under considerꢀ
ation, the ring size is the factor controlling the structural
organization of the mesophase and the tendency to
polymesomorphism. In this connection, it was of interest
to study the compound occupying the intermediate posiꢀ
tion between D4 and D6, viz., cyclopentasiloxane (D5)
cisꢀ[PhSi(O)(OSiMe2R)]5, where R = Me.
organometallasiloxanes (OMS) can be used for the synꢀ
thesis of a new class of stereoregular organocyclosiloxanes.
A procedure for the synthesis of the starting OMS is based
on the hydrolytic condensation of organotrialkoxysilanes,
which occurs with the involvement of various metal ions
to give the cyclic organosiloxanolate ligand [RSi(O)O–]n
on a metal ion matrix. The size and configuration of the
cyclic ligand [RSi(O)O–]n depend primarily on the nature
of metal. The removal of metal ions by triorganylꢀ
chlorosilanes or dilute HCl allows the isolation of the
cyclic organosiloxanolate fragment in the form of its
triorganylsiloxy or hydroxy derivative. Studies of the physiꢀ
cal properties of cyclosiloxanes showed3—11 that almost
all these compounds exhibit the mesomorphic properties
in a wide temperature range.
We have also demonstrated3,4,6,7 that organoꢀ
cyclosiloxanes (OSC) of the general formula
cisꢀ[PhSi(O)(OSiMe2R)]n (n = 4 or 6; R = Me, CH2Cl,
or HC=CH2), which were synthesized from the correꢀ
sponding metallasiloxanes, are transformed into the meꢀ
somorphic state above the melting point of the crystalline
phase. It was found3,4 that all cyclotetrasiloxanes with
n = 4 (D4) form 3D plasticꢀcrystalline mesophases regardꢀ
less of the structure of the side groups R. In 3D mesoꢀ
phases, molecules of all compounds D4 occupy the bodyꢀ
centered cubic (BCC) lattice points.3,4 The mesomorphic
properties change substantially as the size of the siloxane
ring increases to n = 6, i.e., in cyclohexasiloxanes (D6).6,7
Earlier,12—14 when studying the properties of OMS,
we have found that the cyclic organosiloxanolate ligand
can undergo rearrangements and the chemical composiꢀ
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1353—1358, July, 2007.
1066ꢀ5285/07/5607ꢀ1402 © 2007 Springer Science+Business Media, Inc.

Penta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 7, July, 2007
1403
120 °C to constant weight. The solvents were purified according
to known procedures.16 Compound 1 was synthesized as deꢀ
scribed earlier.14
The 1H and 29Si NMR spectra were recorded on a Bruker
1
AMX spectrometer (400.1 MHz for H and 79.5 MHz for 29Si)
at 20 °C in CDCl3. The DSC measurements were carried out on
a Mettlerꢀ822е differential scanning calorimeter at a heatꢀ
ing/cooling rate of 20 deg min–1 under argon. The position of
the minimum (maximum) of the peak in the DSC curve was
taken as the transition temperature. Xꢀray diffraction studies
were performed on a Dronꢀ3M diffractometer (CuꢀKα radiaꢀ
tion, a curved quartz crystal as the pointꢀfocusing monochroꢀ
mator) equipped with a highꢀtemperature chamber (temperaꢀ
ture was maintained within 1 °C). The Xꢀray diffraction patꢀ
terns were measured in the transmission mode. The optical meaꢀ
surements were performed on a POLAMꢀ213M polarization
microscope.
C
Cu
N
O
Si
Fig. 1. Molecular structure of compound 1.
cisꢀPenta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane (2).
Compound 1 (0.6 g, 0.276 mmol) was placed in a flask, pyridine
(0.8 mL, 0.79 g, 9.942 mmol) was added, and then a solution of
trimethylchlorosilane (1.68 mL, 1.44 g, 13.256 mmol) in hexane
(25 mL) was added with stirring. The reaction mixture was reꢀ
fluxed for 1 h, cooled to ~20 °C, and filtered off from the
precipitate. The filtrate was washed with water until Cl– ions
disappeared and then dried over Na2SO4. The solution was filꢀ
tered, and the solvent was removed (10 Torr, 50 °C) on a rotary
evaporator in vacuo (1 Torr, 50 °C). The yield of the waxy white
product was 0.45 g (77.6%). Found (%): C, 50.93; H, 6.68;
Si, 26.11. [PhSi(O)(OSiMe3)]5, C45H70Si10O10. Calculated (%):
C, 51.38; H, 6.71; Si, 26.70.
Note. Fig. 1 is available in full color in the onꢀline version of the
journal (http://www.springerlink.com/issn/1573ꢀ9171/current)
and on the webꢀsite of the journal (http://russchembull.ru).
tion of the metallasiloxane molecule can be changed in
the presence of strong electron donors. In particuꢀ
lar, Cu/Naꢀphenylsiloxane {Na4[(PhSi(O)O)12Cu4]}•
•8BuOH15 based on the 12ꢀmembered ligand trisꢀcisꢀtrisꢀ
transꢀ[PhSi(O)O–]12 is rearranged to give another copper
complex, viz., {Cu6[(PhSi(O)O)5]2(OH)2(C10H8N2)2}•
•4(DMF)•3H2O (1), in DMF in the presence of 2,2´ꢀbiꢀ
pyridyl. The molecule of the latter complex contains two
cisꢀcyclopentasiloxanolate ligands cisꢀ[PhSi(O)O–]5 and
two 2,2´ꢀbipyridyl molecules coordinated on a matrix conꢀ
sisting of six copper ions (Fig. 1).
1H NMR (Fig. 2), δ: 0.194 (s, 9 H, OSi(CH3)3); 6.95—7.23
(m, 5 H, O3SiC6H5); the integrated intensity ratio of the signals
for the protons of OSi(CH3)3 and O3SiC6H5 was 9 : 5. 29Si NMR
(see Fig. 2), δ: –81.32 (s, O3SiC6H5); 9.99 (s, OSi(CH3)3).
In
the
present
study,
we
synthesized
cisꢀpenta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
cisꢀ[PhSi(O)(OSiMe3)]5 (2) by the reaction of compound
1 with trimethylchlorosilane according to Scheme 1 and
investigated the properties of compound 2.
Results and Discussion
At ~20 °C, compound 2 is waxy and very viscous. To
study the optical properties, this compound was placed
between two cover slips and pressed to prepare a thin
layer. At ~20 °C, compound 2 gives a pronounced honeyꢀ
comb texture under normal light (Fig. 3, a). The bireꢀ
fringence was not observed through crossed polaroids
(Fig. 3, b). The observed honeycomb texture (see Fig. 3, a)
is analogous to the soꢀcalled Bernard cells, whose appearꢀ
ance is associated with the free convection.17—19 Earlier,
we have found analogous honeycomb textures for a series
of plastic crystals of octaphenylcyclotetrasiloxane,4 D4,4
and their mixtures,20 as well as for some bifunctional
decamethylcyclohexasilanes.21
Scheme 1
Upon heating to 165 °C, compound 2 possesses the
birefringent properties, and the texture is retained in the
observations both through crossed polaroids and under
normal light (Fig. 3 b, d) up to its sublimation temperaꢀ
ture (365 °C). Hence, compound 2 exists presumably
in the plasticꢀcrystalline mesomorphic state at 20 °C
(mesophase 1), and the polymesomorphic transition of
this compound occurs at ~165 °C.
Experimental
Trimethylchlorosilane (Aldrich), pyridine (Aldrich), hexane
(reagent grade), and NaOH (analytical grade) were used. Anꢀ
hydrous CuCl2 was prepared by heating the crystal hydrate at

1404
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 7, July, 2007
Molodtsova et al.
a
O3SiC6H5
O3Si(CH3)3
7.2
6
7.1
7.0
5
δ
0.3
0.2
2
0.1
δ
7
4
3
1
δ
b
O3Si(CH3)3
O3SiC6H5
10.4
10.0
δ
–81.2
–81.6
δ
10
0
–10
–20
–30
–40
–50
–60
–70
δ
Fig. 2. 1H NMR (a) and 29Si NMR (b) spectra of compound 2.
According to the DSC data (Fig. 4), compound 2 does
not crystallize. The DSC curves obtained by a heating
scan show a heatꢀcapacity jump associated with the deꢀ
vitrification of the plasticꢀcrystalline mesophase at –56 °C
(∆CP = 0.19 J g–1 K–1) and an endothermic peak with a
maximum at 164 °C and ∆H = 0.9 J g–1 (see Fig. 4).
Taking into account the results of polarization microꢀ
scopy, it can be concluded that the first thermal effect is
associated with the devitrification of the plasticꢀcrystalꢀ
line mesophase, and the second effect, whose temperaꢀ
ture coincides with the appearance of the birefringence, is
associated with the polymesomorphic transition mesoꢀ
phase 1 → mesophase 2. The cooling curve shows an
exothermic peak at 121 °C and ∆H = 0.91 J g–1 correꢀ
sponding to the transition mesophase 2 → mesophase 1
and a heat capacity jump corresponding to the glass tranꢀ

Penta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 7, July, 2007
1405
a
c
100 µm
100 µm
b
d
100 µm
100 µm
Fig. 3. Transmission micrographs of compound 2 under normal (a, b) and polarized (c, d) light at 25 (a, c) and 200 °C (b, d).
measured Xꢀray diffraction patterns for compound 2 at
different temperatures.
2
3
The Xꢀray diffraction pattern of compound 2 at 20 °C
(Fig. 5, a) contains five narrow (∆1/2 = 0.25°) reflections
at 2θ = 8.39, 11.88, 14.56, 16.83, and 18.83° and a broad
amorphous halo at 2θ = 13—30° with a maximum at
2θ ~18°. This Xꢀray diffraction pattern is typical of mesoꢀ
morphic systems. Since sin2θ for the adjacent reflections
are in a ratio of 1 : 2 : 3 : 4 : 5, this mesophase can be
considered as cubic. This is also evidenced by the optical
isotropism of the mesophase at 20 °C (see Fig. 3, a).
Therefore, the Xꢀray diffraction data confirm the validity
of the assignment of mesophase 1 of compound 2 to plasꢀ
tic crystals. Based on the ratio between sin2θ, the reflecꢀ
tions can be indexed both in the simple and BCC lattices.
However, the packing coefficient k calculated assuming
the simple cubic lattice was unrealistic.22 The analogous
calculation assuming the bodyꢀcentered cubic lattice with
the unit cell parameter a = 14.90 Å (20 °C) gave good
results. Actually, the sum of the van der Waals volumes of
the atomic increments involved in molecule 2 Σ∆Vi =
1005.7 Å3, and the volume of the BCC unit cell at 20 °C
V = 3307.95 Å3, which corresponds to k ~0.61. In this
case, the observed reflections should be indexed as 110,
200, 211, 220, and 310.
1
–50
0
50
100
150
T/°C
Fig. 4. DSC curves for compound 2 during the first (1) and
second heating scans (2) and the cooling scan (3) at a rate of
20 deg min–1 under argon.
sition of mesophase 1 at –69 °C (∆CP = 0.19 J g–1 K–1).
The thermodynamic parameters of the observed transiꢀ
tions both during the first and second heating scans and
during the cooling scan remain unchanged. The observed
hysteresis of the polymesomorphic phase transition temꢀ
perature and the glass transition temperature can be atꢀ
tributed to low rates of these transitions, which are maniꢀ
fested at rather high heating—cooling rates.
To confirm these conclusions and to determine the
type of ordering of the mesomorphic modifications, we

1406
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 7, July, 2007
Molodtsova et al.
I (rel. units)
tions at 2θ = 7.27, 7.92, 8.59, 11.74, 12.56, and 13.83°.
This set of reflections can be indexed in different ways,
which complicates the determination of the unit cell type
and, consequently, the type of ordering in the mesophase.
However, taking into account the characteristic features
of plastic crystals and based on the published data,23 some
conclusions can be drawn on the character of structural
changes at 165 °C. The low packing coefficient characterꢀ
istic of the BCC lattice immediately before the phase
transition at 165 °C and the appearance of the birefrinꢀ
gence above the polymesomorphic phase transition temꢀ
perature provide convincing evidence for the hexagonal
closeꢀpacked (HCP) lattice of the HT mesophase. Actuꢀ
ally, the BCC lattice → HCP lattice transition should be
accompanied by the appearance of the birefringence and
an increase in the packing coefficient k. In this case, an
increase in the coefficient k is a necessary condition for
the existence of the HT mesophase. When considering
the Xꢀray diffraction pattern from this point of view, the
observed reflections can be indexed as 101, 003, 012, 104,
112, and 202 for the HCP lattice with the unit cell paramꢀ
eters a = 15.07 Å and c = 33.49 Å, the systematic abꢀ
sences h + k + l = 3n for the HCP lattice being strictly
fulfilled. In this case, the calculated packing coeffiꢀ
cient k (0.61) can be considered as satisfactory only on
the condition that the HCP unit cell contains four molꢀ
ecules. Evidently, another unit cell type, for example,
a tetragonal or orthorhombic unit cell, can be proposed.
However, a lowering of the symmetry of the unit cell with
increasing temperature seems to be unlikely. Conseꢀ
quently, it should be assumed that the highꢀtemperature
HCP lattice points are occupied by noncovalently bonded
dimers, whose stability is, apparently, determined by
diphilicity of molecules 2. Molecules 2 are characterized
by the disturbed upꢀandꢀdown symmetry, which can be
favorable for this type of molecular aggregation. In addiꢀ
tion, according to the published data,23 two molecules
with the antiprismatic arrangement of the fiveꢀmembered
rings can form layers with the coordination number of six.
However, the absence of this segregation of molecules 2
in the LT mesophase (where this is theoretically more
probable, by analogy with cyclohexasiloxanes6,7) remains
unclear.
a
I (rel. units)
70
50
30
1200
800
400
15
20
25
2θ/deg
2θ/deg
0
5
10
15
20
I (rel. units)
I (rel. units)
b
1200
800
100
50
400
15
20
2θ/deg
2θ/deg
0
5
10
15
20
25
Fig. 5. Xꢀray diffraction patterns of compound 2 at 20 (a) and
178 °C (b).
The rise of the temperature leads to a substantial shift
of the angular positions of reflections toward smaller valꢀ
ues and a decrease in the number of reflections, which is
typical for mesomorphic systems, including plastic crysꢀ
tals. For example, the Xꢀray diffraction pattern measured
at 110 °C contains only three reflections at 2θ = 8.21,
11.62, and 14.24°, which corresponds to an increase in
the unit cell parameter a of the BCC lattice to 15.23 Å
and a decrease in the packing coefficient k to 0.57. At
140 °C, the Xꢀray diffraction pattern contains only two
reflections at 2θ = 8.12 and 11.49°, and the parameter a
increases to 15.40 Å. In this case, the packing coeffiꢀ
cient k decreases to the critical value for the condensed
state (0.55). Such low values are usually observed near
the isotropic transition point of mesomorphic systems.
However, compound 2 undergoes the structural polyꢀ
mesomorphic transition in the temperature range of
140—150 °C, as evidenced by the changes in the Xꢀray
diffraction pattern (Fig. 5, b). This result correlates with
the DSC data (see Fig. 4) and the results of polarization
microscopy (see Fig. 3).
Therefore, using the newly synthesized compound 2
as an example, we demonstrated that molecules of cyclic
siloxanes with the disturbed upꢀandꢀdown symmetry are
strongly prone to the selfꢀorganization giving rise to orꢀ
dered structures. Due to the low molecular symmetry,
cyclopentasiloxane 2 is a noncrystallizable compound.
However, molecules 2 form a 3D mesomorphic structure
(plastic crystals), which is stable throughout the temperaꢀ
ture range below the temperature of destruction. The
polymesomorphism of compound 2 is also associated with
the selfꢀorganization processes resulting in the rearrangeꢀ
ment of the location of the molecules with a low packing
The Xꢀray diffraction pattern of compound 2 meaꢀ
sured at >165 °C (see Fig. 5, b) contains a series of reflecꢀ

Penta[(phenyl)(trimethylsiloxy)]cyclopentasiloxane
Russ.Chem.Bull., Int.Ed., Vol. 56, No. 7, July, 2007
1407
9. Yu. A. Molodtsova, E. V. Matukhina, M. I. Buzin, V. G.
Vasil´ev, and O. I. Shchegolikhina, Abstrs. of Papers, Intern.
Conf. Dedicated to 50th Anniversary of A. N. Nesmeyanov
Institute of Organoelement Compounds (INEOS), Russian
Academy of Sciences, "Modern Trends in Organoelement and
Polymer Chemistry" (Moscow, Russia, May 30—June 4, 2004),
Moscow, 2004, Pꢀ57 (POLY).
10. Yu. A. Molodtsova, Yu. A. Pozdniakova, E. V. Matukhina,
I. V. Blagodatskikh, V. G. Vasil´ev, M. I. Buzin, N. S.
Semenova, and O. I. Shchegolikhina, Abstrs. of Papers, Intern.
Conf. "From Molecules to Materials" (Nizhnii Novgorod, Rusꢀ
sia, September 3—11, 2005), Nizhnii Novgorod, 2005, O57.
11. Yu. A. Molodtsova, Ph. D. (Chem.) Thesis, A. N.
Nesmeyanov Institute of Organoelement Compounds, Rusꢀ
sian Academy of Sciences, Moscow, 2005, 187 pp. (in
Russian).
12. Yu. A. Molodtsova, Yu. A. Pozdniakova, K. A. Lyssenko,
J. W. Bats, N. Auner, and O. I. Shchegolikhina, Abstrs. of
Papers, Mark Vol´pin Memorial Intern. Symp. "Modern Trends
in Organometallic and Catalytic Chemistry" (Moscow, Russia,
May 18—23, 2003), Moscow, 2003, Pꢀ132.
13. Yu. Molodtsova, L. Zherlytsina, J. Bats, M. Bolte,
V. Pashchenko, N. Auner, and O. Shchegolikhina, Abstrs. of
Papers, 14th Intern. Symp. on Organosilicon Chemistry,
3rd Europ. Organosilicon Days (Wuerzburg, Germany,
July 31—August 5, 2005), Wuerzburg, 2005, 217, P190.
14. V. Pashchenko, B. Brendel, B. Wolf, M. Lang, K. Lyssenko,
O. Shchegolikhina, Y. Molodtsova, L. Zherlitsyna, N. Auner,
F. Schutz, M. Kollar, P. Kopietz, and N. Harrison, Eur.
J. Inorg. Chem., 2005, 4617.
coefficient, without allowing the transition of the comꢀ
pound to the isotropic state.
A comparison of the results of the present study with
the data obtained earlier4,7 revealed the regularities of the
changes in the mesomorphic properties of a series of OCS
of the general formula cisꢀ[PhSi(O)(OSiMe3)]n (n = 4, 5,
or 6). An increase in the size of the cyclic fragment of
OCS has virtually no effect on thermal stability of the
mesomorphic state. The highꢀtemperature boundary of
the temperature range of the existence of the mesophase
is determined by the sublimation temperature of OCS. At
the same time, the size of the cyclic fragment of OCS has
a substantial effect on the type of ordering in the mesoꢀ
phase and the possibility of polymesomorphism. Thus,
D4 forms one mesomorphic modification, viz., a plastic
crystal with the BCC lattice. Compound 2 (D5) behaves
analogously to D4 at low temperatures and forms plastic
crystals with the BCC lattice; however, compound 2 exꢀ
hibits the polymesomorphic properties and forms plastic
crystals with the nonꢀcubic lattice, which is most likely
the 3D hexagonal closeꢀpacked lattice, as the temperaꢀ
ture is raised.
This study was financially supported by the Russian
Foundation for Basic Research (Project Nos 04ꢀ03ꢀ
321080 and 04ꢀ03ꢀ32853).
References
15. Yu. A. Molodtsova, Yu. A. Pozdniakova, K. A. Lyssenko,
I. V. Blagodatskikh, D. E. Katsoulis, and O. I.
Shchegolikhina, Organomet. Chem., 1998, 571, 31.
16. A. J. Gordon and R. A. Ford, The Chemist´s Companion,
A WileyꢀIntersci. Publ., New York—London—Sydney—
Toronto, 1972.
17. J. T. Lir and T. F. Lin, Intern. J. Heat and Mass Transfer,
2001, 44, 2889.
18. E. Arquis and M. Rady, Intern. J. Thermal Sciences,
2005, 44, 43.
1. O. I. Shchegolikhina, V. A. Igonin, Yu. A. Molodtsova,
Yu. A. Pozdniakova, A. A. Zhdanov, T. V. Strelkova, and
S. V. Lindeman, J. Organomet. Chem., 1998, 562, 141.
2. O. I. Shchegolikhina, Yu. A. Pozdniakova, Yu. A.
Molodtsova, S. D. Korkin, S. S. Bukalov, L. A. Leites, K. A.
Lyssenko, A. S. Peregudov, N. Auner, and D. E. Katsoulis,
Inorg. Chem., 2002, 41, 6892.
3. O. Shchegolikhina, L. Matukhina, Yu. Pozdniakova, and
D. Katsoulis, Abstrs. of Papers, 33rd Organosilicon Sympoꢀ
sium (Saginaw, Michigan, USA, April 6—8, 2000), Saginaw,
2000, Aꢀ12.
4. E. V. Matukhina, O. I. Shchegolikhina, N. N. Makarova,
Yu. A. Pozdniakova, D. Katsoulis, and Yu. K. Godovskiy,
Liq. Cryst., 2001, 28, 869.
5. O. Shchegolikhina, E. Matukhina, Yu. Molodtsova,
Yu. Pozdniakova, and D. Katsoulis, Abstrs. of Papers, Intern.
Conf. on Inorganic Ring Systems (Saarbruecken, Germany,
July 23—28, 2000), Saarbruecken, 2000, O14.
19. E. Bilgen and M. Mbaye, Intern. J. Heat and Fluid Flow,
2001, 22, 561.
20. G. G. Nikiforova, V. G. Vasil´ev, E. G. Belenova, E. V.
Matukhina, and O. I. Shchegolikhina, Tez. dokl., 10 Vseros.
konf. "Kremniiorganicheskie soedineniya: sintez, svoistva,
primenenie" [Abstrs. of Papers, 10th AllꢀRussian Conf. "Organoꢀ
silicon Compounds: Synthesis, Properties, and Application"]
(Moscow, May 26—30, 2005), Moscow, 2005, 1C43 (in
Russian).
21. D. Yu. Larkin, A. A. Korlyukov, E. V. Matukhina, M. I.
Buzin, N. A. Chernyavskaya, M. Yu. Antipin, and A. I.
Chernyavskii, Izv. Akad. Nauk, Ser. Khim., 2005, 1566 [Russ.
Chem. Bull., Int. Ed., 2005, 54, 1612].
6. O. I. Shchegolikhina, E. V. Matukhina, and D. Katsoulis,
Abstrs. of Papers, 34th Organosilicon Symposium (White Plains,
New York, USA, May 3—5, 2001), White Plains, 2001, Bꢀ21.
7. E. V. Matukhina, O. I. Shchegolikhina, Yu. A. Molodtsova,
Yu. A. Pozdniakova, K. A. Lyssenko, V. G. Vasil´ev, and
M. I. Buzin, Liq. Cryst., 2004, 31, 401.
22. A. I. Kitaigorodsky, Molecular Crystals and Molecules, No. 29,
Ser. Physical Chemistry, Ed. E. M. Loebl, Academic Press,
New York—London, 1973.
8. O. I. Shchegolikhina, Yu. A. Pozdniakova, Yu. A.
Molodtsova, K. A. Lyssenko, E. V. Matukhina, N. Auner,
and D. Katsoulis, Abstrs. of Papers, 2nd Europ. Organosilicon
Days (Munich, Germany, September 11—12, 2003), Munich,
2003, A5.
23. The Plastically Crystalline State (OrientationallyꢀDisordered
Crystals), Ed. N. Sherwood, Wiley, New York—London, 1979.
Received November 22, 2006;
in revised form May 24, 2007