Unprecedented formation of cis- and trans-di[(3-chloropropyl) isopropoxysilyl]-bridged double-decker octaphenylsilsesquioxanes

Article abstract of DOI:10.1002/ejic.201300283

Silsesquioxane formation competing with the deprotonation of alcohol solvents in the presence of a strong base to form alkoxides is reported for the first time. Evidently, sodium isopropoxide is formed during the synthesis of the sodium salt of a double-decker octaphenylsilsesquioxane tetrasilanolate in 2-propanol as the solvent, which leads to the formation of unexpected cis- and trans-di[(3-chloropropyl)isopropoxysilyl]-bridged double-decker octaphenylsilsesquioxanes after in situ coupling with 3- chloropropyltrichlorosilane. The desired products were characterized by ¹H NMR, ¹³C NMR, and ²⁹Si NMR spectroscopy; ESI-MS; and single-crystal X-ray diffraction. During the synthesis of the sodium salt of double-decker octaphenylsilsesquioxane tetrasilanolate in 2-propanol, sodium isopropoxide is formed, which leads to the formation of unexpected cis- and trans-di[(3-chloropropyl)isopropoxysilyl]-bridged double-decker octaphenylsilsesquioxanes after in situ coupling with 3- chloropropyltrichlorosilane. Copyright

Full text of DOI:10.1002/ejic.201300283

SHORT COMMUNICATION
DOI:10.1002/ejic.201300283
Unprecedented Formation of cis- and trans-Di[(3-
chloropropyl)isopropoxysilyl]-Bridged Double-Decker
Octaphenylsilsesquioxanes
Vuthichai Ervithayasuporn,*[a,b] Rapheepraew Sodkhomkhum,[a]
Thapong Teerawatananond,[c] Chuttree Phurat,[c]
Pranee Phinyocheep,[a] Ekasith Somsook,[a] and
Tanakorn Osotchan[b,d]
Dedicated to Professor Dr. James W. Pavlik and Professor Dr. Yusuke Kawakami on the occasion of their retirement
Keywords: Organic–inorganic hybrid composites / Main group elements / Silanes / Silsesquioxanes
Silsesquioxane formation competing with the deprotonation
of alcohol solvents in the presence of a strong base to form
alkoxides is reported for the first time. Evidently, sodium iso-
propoxide is formed during the synthesis of the sodium salt
of a double-decker octaphenylsilsesquioxane tetrasilanolate
in 2-propanol as the solvent, which leads to the formation of
unexpected cis- and trans-di[(3-chloropropyl)isopropoxysil-
yl]-bridged double-decker octaphenylsilsesquioxanes after
in situ coupling with 3-chloropropyltrichlorosilane. The de-
sired products were characterized by 1H NMR, 13C NMR,
and 29Si NMR spectroscopy; ESI-MS; and single-crystal X-
ray diffraction.
Introduction
and hybrid nanoassemblies.[5] So far, the number of avail-
able reactive double-decker silsesquioxane monomers has
been limited, because isolated precursor 2 is most likely to
exist in a mixture of sodium salts.[1i,2a] Therefore, the reac-
tion progress during the formation of the sodium salt of
double-decker silsesquioxanes must be investigated.
In this report, we explore the use of sodium isopropoxide
(3) during the synthesis of 2. After coupling 2 with 3-chlo-
ropropyltrichlorosilane, we found that 3 plays a crucial role
in the formation of an isomeric mixture of unexpected
products cis- and trans-di[(3-chloropropyl)isopropoxysilyl]-
bridged double-decker octaphenylsilsesquioxane (5). For fu-
ture aspects, it is noteworthy that these novel double-decker
monomers could be further functionalized through nucleo-
philic substitution, as a method has already been proved to
be efficient to obtain new silsesquioxane materials in high
yield.[6]
The sodium salt of double-decker octaphenylsilsesquiox-
ane tetrasilanolate (2) is classified as one of the promising
precursors of polyhedral oligomeric silsesquioxanes.[1] They
have recently been coupled with dialkyldichlorosilanes[2]
and alkyltrichlorosilanes[3] and later transformed into a new
type of condensed polyhedral structures. Nowadays, these
promising double-decker silsesquioxane monomers are con-
sidered to be novel types of carbosilane and siloxane mate-
rials that provide several specific properties such as heat
resistance,[3] and they have been used in optoelectronic[4]
[a] Department of Chemistry and Center of Excellence for
Innovation in Chemistry (PERCH-CIC), Faculty of Science,
Mahidol University,
Rama VI road, Ratchathewi, Bangkok 10400, Thailand
Fax: +66-2-354-7151
E-mail: vuthichai.erv@mahidol.ac.th
Homepage: http://chemistry.sc.mahidol.ac.th/en/people/faculty/
vuthichai-ervithayasuporn/
[b] Capability Building Unit for Nanoscience and Nanotechnology,
Faculty of Science, Mahidol University,
Rama VI road, Ratchathewi, Bangkok 10400, Thailand
[c] Biomaterials and Bioorganic Chemistry Research Group,
Department of Chemistry, Faculty of Science, Chulalongkorn
University,
Phayathai road, Pathumwan, Bangkok 10330, Thailand
[d] Department of Physics, Faculty of Science, Mahidol University,
Rama VI road, Ratchathewi, Bangkok 10400, Thailand
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.201300283.
Results and Discussion
The synthesis of 2 was first proposed by Yoshida et al.
through hydrolytic condensation of phenyltrimethoxysilane
in alkaline solution.[1a] Later, Woo, and Kawakami studied
the conversion of the sodium salt of heptaphenylsilses-
quioxane trisilanolate (1) into 2.[2a] In fact, compounds 1
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and 2 shown in Scheme 1 are likely found in an equilibrium
Second, the major product consisted of an isomeric mix-
mixture, which was isolated as coprecipitated sodium ture of cis-5/trans-5 in equal ratios. These compounds have
salts.[1i,2a] Thus, there is no direct evidence of characteriza- an identical Rf value of 0.15. The mixture was isolated in
tion of these materials, because of their poor solubility in 14% yield, and its structure was confirmed by its distin-
organic solvents. However, the original structures could guishable 29Si{1H} NMR spectrum (Figure S7, Supporting
only be determined qualitatively after treatment with or- Information). The signals at δ = –61.26, –79.08, –79.13, and
ganosilanes to obtain more-soluble materials.[2,4a] Kawak- –79.57 ppm are assigned to the cis isomer, whereas the sig-
ami et al. first attempted the coupling of isobutyltrichloros- nals at δ = –61.26, –79.08, and –79.35 ppm are assigned to
ilane to these precipitated mixtures of sodium salts; how- the trans isomer. This result is also consistent with our pre-
ever, the only products found were hydrolyzable cis- and vious report on the existence of isomeric mixtures of cis-
trans-di[(isobutyl)silanol]-bridged double-decker octaphen- and trans-di[(3-chloropropyl)methyl]-bridged double-decker
ylsilsesquioxanes. The separation of the desired materials octaphenylsilsesquioxane.[2b] Interestingly, its 1H NMR
could be easily achieved by precipitation from a toluene spectrum exhibits unknown signals at δ = 4.35 and
solution, but no further analysis of the soluble products in 1.09 ppm, whereas the integrated intensity of the other sig-
the mother liquid was performed.[4a] In contrast, in our ex- nals confirms the protons on eight aromatic rings and di-
periments involving the coupling of 2 with 3-chloroprop- bridging 3-chloropropyl side chains in a double-decker
yltrichlorosilane in a similar manner (Scheme 1), only 3- structure. To draw a molecular picture, mass spectrometry
chloropropyl heptaphenylsilsesquioxane (4) could be de- (ESI-MS) may give useful evidence associated with the ap-
tected and identified among the insoluble products. This pearance of the molecular ion at m/z = 1417.0561 (Fig-
result strongly confirms that not only double-decker so- ure S8, Supporting Information). This result strongly sug-
dium salt 2 was formed but also that T7 sodium salt 1 exists gests that the double-decker backbone must be covalently
in the precipitated mixture during double-decker formation. attached to unexpected dibridging isopropoxysilyl substitu-
In addition, we further analyzed the other soluble products ents. Consequently, we hypothesize that this unexpected for-
in the toluene solution, and our results obtained by thin- mation of 5 could actually support the presence of 3 among
layer chromatography (CH2Cl2/hexane = 1:4 v/v) analysis precipitated mixtures of 1 and 2 and could involve isoprop-
of the mother liquid revealed the existence of three major oxide–chloride exchange during the coupling reaction with
compounds (Rf = 0.35, 0.15, 0). After purification by col- 3-chloropropyltrichlorosilane to form completely con-
umn chromatography to separate each pure compound, we densed double-decker silsesquioxane. Thus, such an inter-
found that the least polar (Rf = 0.35) compound was the mediate was not suggested elsewhere, after the synthesis of
octameric T8 silsesquioxane of 4, which was first isolated in 2 was known. Herein, we suggest that under strongly basic
9% yield in a pure form.
conditions, the deprotonation of any alcohol solvent to
Scheme 1. Synthetic approach to the formation of cis- and trans-di[(3-chloropropyl)isopropoxysilyl]-bridged double-decker octaphenylsil-
sesquioxane (5).
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form alkoxides competes with the formation of silsesquiox-
Conclusions
ane materials, and researchers should be aware of this fact.
Further attempts to separate each pure isomer from the
cis-5/trans-5 mixture by recrystallization in THF/hexane
(1:1) successfully provided colorless crystals of pure trans-
5. In Figure 1, the perspective view of trans-5 obtained by
single-crystal X-ray diffraction analysis is displayed, and its
crystalline data and structural refinement parameters are
summarized in Tables S1 and S2 (Supporting Information).
The discovery of sodium isopropoxide (3) during the for-
mation of the sodium salt of double-decker octaphenylsil-
sesquioxane (1) by coincidence of the deprotonation of 2-
propanol as the solvent under strongly basic conditions has
been reported for the first time. Thus, 3 plays a crucial role
in an isopropoxide–chloride exchange reaction during the
coupling of 1 with slightly sterically hindered 3-chloroprop-
yltrichlorosilane, which directly leads to the formation of
unexpected cis- and trans-di[(3-chloropropyl)isopropoxysil-
yl]-bridged double-decker octaphenylsilsesquioxane (5). Fi-
nally, the authors believe that the use of these novel mono-
mers in polymerization and functionalization through nu-
cleophilic substitution reactions to obtain various func-
tional materials should be considered in the near future.
Experimental Sections
Materials and Methods: Phenyltrimethoxysilane and 3-chloroprop-
yltrichlorosilane were obtained from Tokyo Chemical Industry Co.,
Ltd., and used without additional purification. 2-Propanol and
THF were purchased from B&J Company. THF was further dried
with sodium metal and distilled under anhydrous conditions. Fou-
rier-transform NMR spectra were obtained by using Bruker-AV
300 for 1H (300 MHz) and Bruker-AV 500 high-resolution NMR
spectrometers for 1H (500 MHz), 13C{1H} (125 MHz), and
29Si{1H} (99 MHz). The chemical shifts are reported in δ units
(parts per million) relative to SiMe4 (TMS), and the residual sol-
vents peaks (CHCl3) were used for reference. High-resolution mass
spectrometry was performed by using a Micromass VQ-TOF 2.
Figure 1. Thermal ellipsoid plot of trans-5 at the 30% probability
level; hydrogen atoms are omitted for clarity.
Other double-decker products were obtained in trace
amounts (Ͻ5% yield) from fractions obtained at a later
stage during purification by column chromatography. Par-
tially hydrolyzed di(3-chloropropyl)[(isopropoxysilyl)sil-
anol]-bridged double-decker octaphenylsilsesquioxane (6)
could be isolated by gradient elution [Rf = 0.31, CH2Cl2/
hexane (2:3)]. Its NMR spectra (Figures S17–S19, Support-
ing Information) also confirm that one side of the bridging
double-decker is already hydrolyzed to a silanol group,
whereas the other still remains alkylated. Moreover, com-
X-ray Structural Determination: Crystalline trans-5 suitable for X-
ray structural analysis was obtained by recrystallization in THF/
hexane. X-ray data were collected with a Bruker SMART APEX
II CCD area-detector diffractometer with a Mo-Kα radiation
source (λ = 0.7107 Å) at 296 K. The crystal structures were solved
by direct methods with SHELXS-97.[7] The full-matrix least-
squares procedures by using SHELXL-97 on F2 anisotropic for all
non-hydrogen atoms was used to refine the crystal structures. Hy-
drogen atoms were placed in their calculated positions and refined
following the riding model.
CCDC-912558 (for trans-5) contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
pletely
hydrolyzed
di[(3-chloropropyl)silanol]-bridged
double-decker octaphenylsilsesquioxane (7) was also col-
lected in a trace amount (Rf = 0.50, CH2Cl2). In fact, this
isolated fraction was found to be insoluble in chloroform,
dichloromethane, and THF but showed good solubility in
DMSO. However, the majority of the peaks in the 29Si{1H}
NMR spectrum (Figure S23, Supporting Information) in
[D6]DMSO can be attributed to the trans isomer. We sug-
gest that most of cis-7/trans-7 is possibly excluded as an
insoluble material as a result of its poor solubility in com-
mon organic solvents. Unlikely, hydrolyzable cis- and trans-
di[(isobutyl)silanol]-bridged double-decker octaphenylsil-
sesquioxanes could be considered to be more soluble in or-
ganic solvents because of the hydrophobic incorporation of
the isobutyl groups into the double-decker structure.[4a]
These hydrolytic products can be possibly formed after
quenching with an aqueous solution under acid–base con-
ditions.
Synthesis of the Sodium Salt of Heptaphenylsilsesquioxane Trisilan-
olate (1), the Tetrasodium Salt of Double-Decker Octaphenylsilses-
quioxane (2), and Sodium Isopropoxide (3): Phenyltrimethoxysilane
(50 mL, 47.6 g, 0.27 mol) was added dropwise to a solution 2-prop-
anol (260 mL), deionized water (5.5 mL, 0.31 mol), and sodium hy-
droxide (7.12 g, 0.18 mol) at room temperature for 15 min. The re-
action mixture was heated at reflux for 4 h to obtain a milky-white
precipitate. The suspension solution was cooled down at room tem-
perature and left overnight. It was subsequently filtered and washed
with 2-propanol and dried at 60 °C for 5 h under vacuum to obtain
a completely dry white powder mixture of sodium salts 1, 2, and 3
(22.15 g).
Synthesis of cis- and trans-Di[(3-chloropropyl)isopropoxysilyl]-
Bridged Double-Decker Octaphenylsilsesquioxane (5): Under a dry
argon atmosphere, a mixture of anhydrous THF (260 mL), sodium
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salts 1, 2, and 3 (25.81 g), and triethylamine (9.29 mL, 66.81 mmol)
was cooled down to 0 °C in an ice bath. 3-Chloropropyltrichlorosi-
lane (14.16 g, 10.49 mL, 66.81 mmol) was added dropwise over
10 min. After warming to room temperature overnight (12 h), the
mixture was then cooled down to 0 °C again before the addition of
a saturated NaHCO3 solution (60 mL) to neutralize and dissolve
any inorganic materials. CH2Cl2 (3ϫ50 mL) was added to extract
the desired products. The combined organic layer was separated,
washed repeatedly with water until it became neutral, washed with
brine, and dried with anhydrous sodium sulfate. Evaporation of the
solvent gave a crude product, which was further dissolved in tolu-
ene (200 mL) to form a suspension. To fully precipitate the insolu-
ble materials, the solution mixture was left in a refrigerator over-
night, at which point it separated into two phases: insoluble white
solid (A) and mother liquid solution (A). The insoluble solid (A,
4.41 g) was collected by filtration and further dissolved in THF to
yield a solution containing some insoluble materials, which were
further removed by filtration. An equivalent volume of ethyl acetate
was added to the remaining clear solution, which was then placed
at room temperature until the complete formation of cubic-like T8
crystal 4 (0.40 g, 0.39 mmol, 9%). Evaporation of the mother liquid
solution (A) yielded a white solid (24.06 g), which was then ana-
lyzed by thin-layer chromatography (CH2Cl2/hexane = 1:4 v/v). The
analysis clearly showed three separate spots at Rf = 0.35 and 0.15
along with a broad baseline (Rf = 0.10–0). Crude product (7.13 g)
was purified by conventional column chromatography (gradient
system CH2Cl2/hexane = 1:4, 1:3, 3:7, 2:3, 1:1, and pure CH2Cl2)
to give an additional product of pure 4 (Rf = 0.35; 0.66 g,
0.64 mmol, 9%) and an isomeric mixture of cis-5/trans-5 (Rf = 0.15;
1.00 g, 0.72 mmol, 14%). Further recrystallization of cis-5/trans-5
in THF/hexane (1:1 v/v) yielded colorless crystals of only pure
trans-5, and evaporation of the remaining solution gave a majority
of cis-5. Thus, 6 [Rf = 0.30, CH2Cl2/hexane (2:3)] and trans-7 (Rf
= 0.50, CH2Cl2) were isolated in only trace amounts (Ͻ5% yield).
Data for 4: 1H NMR (300 MHz, CDCl3): δ = 7.77–7.72 (m, 14 H),
7.50–7.34 (m, 21 H), 3.52 (t, J = 6.6 Hz, 2 H), 1.98 (quint., J =
6.6 Hz, 2 H), 0.99 (t, J = 8.2 Hz, 2 H) ppm. 13C{1H} NMR
(125 MHz, CDCl3, TMS): δ = 134.18, 134.13, 130.84, 130.79,
130.21, 130.12, 127.92, 127.87, 47.11, 26.25, 9.48 ppm. 29Si{1H}
NMR (99 MHz, CDCl3, TMS): δ = –65.61, –78.23, –78.56 ppm.
HRMS (ESI): calcd. for C45H41ClO12Si8 [M + K]+ 1071.0100;
found 1070.9490. Data for cis-5/trans-5 (1:1): 1H NMR (500 MHz,
CDCl3): δ = 7.53–7.11 (m, 40 H), 4.35 (oct., J = 6.2 Hz, 2 H), 3.37
(t, J = 6.8 Hz, 4 H), 1.86 (quint., J = 8.1 Hz, 4 H), 1.09 (d, J =
6.3 Hz, 12 H), 0.82 (m, 4 H) ppm. 13C{1H} NMR (125 MHz,
CDCl3, TMS): δ = 134.19, 134.15, 134.01, 133.98, 133.94, 131.41,
130.61, 130.56, 130.49, 127.90, 127.76, 127.69, 127.62, 65.73, 47.18,
26.52, 25.43, 10.35 ppm. 29Si{1H} NMR [99 MHz, CDCl3, TMS,
Cr(acac)3]: δ = –61.26, –79.08, –79.13, –79.57 (cis-5; relative inten-
sity ratio 1:2:1:1), –61.26, –79.08, –79.35 (trans-5; relative intensity
ratio 1:2:2) ppm. HRMS (ESI): calcd. for C60H66Cl2O16Si10 [M +
Na]+ 1417.1300; found 1417.0561. Data for trans-5: 1H NMR
(500 MHz, CDCl3): δ = 7.57–7.18 (m, 40 H), 4.40 (oct., J = 6.1 Hz,
2 H), 3.41 (t, J = 6.8 Hz, 4 H), 1.90 (m, 4 H), 1.12 (d, J = 6.1 Hz, 12
H), 0.85 (m, 4 H) ppm. 13C{1H} NMR (125 MHz, CDCl3, TMS): δ
= 134.03, 133.99, 131.49, 130.69, 130.57, 130.50, 127.91, 127.71,
65.76, 47.16, 26.58, 25.46, 10.41 ppm. 29Si{1H} NMR [99 MHz,
CDCl3, TMS, Cr(acac)3]: δ = –61.28, –79.11, –79.37 ppm. HRMS
(ESI): calcd. for C60H66Cl2O16Si10 [M + Na]+ 1417.1300; found
132.30, 131.45, 128.78, 128.66, 128.51, 66.61, 48.09, 27.41, 26.32,
11.24 ppm. 29Si{1H} NMR [99 MHz, CDCl3, TMS, Cr(acac)3]: δ
= –61.28, –79.08, –79.34, –79.57 ppm. HRMS (ESI): calcd. for
C60H66Cl2O16Si10 [M + Na]+ 1417.1300; found 1417.1271. Data for
6: 1H NMR (500 MHz, CDCl3): δ = 7.58–7.20 (m, 40 H), 4.40
(oct., J = 6.1 Hz, 1 H), 3.42 (m, 4 H), 1.89 (m, 4 H), 1.13 (d, J =
8.7 Hz, 6 H), 0.94 (m, 2 H), 0.86 (m, 2 H) ppm. 13C{1H} NMR
(125 MHz, CDCl3, TMS): δ = 134.01, 133.96, 133.89, 131.32,
131.11, 130.64, 130.56, 130.43, 127.91, 127.89, 127.73, 127.69,
65.71, 47.18, 26.48, 26.35, 25.40, 10.30 ppm. 29Si{1H} NMR
[99 MHz, CDCl3, TMS, Cr(acac)3]: δ = –56.49, –61.20, –78.62,
–79.00, –79.10, –79.31 ppm. HRMS (ESI): calcd. for
C57H60Cl2O16Si10 [M + Na]+ 1375.0800; found 1375.0634. Data for
trans-7: 1H NMR (300 MHz, CDCl3): δ = 7.56–7.18 (m, 40 H),
3.40 (t, J = 6.5 Hz, 4 H), 2.74 (br., 2 H), 1.90 (m, 4 H), 0.93 (t, J
= 8.5 Hz, 4 H) ppm. 13C{1H} NMR (125 MHz, CDCl3, TMS): δ =
134.01, 133.89, 131.08, 130.59, 130.36, 127.91, 127.74, 47.17, 26.34,
10.29 ppm. 29Si{1H} NMR [99 MHz, [D6]DMSO, TMS, Cr-
(acac)3]: δ = –58.11, –78.96, –79.25 ppm. HRMS (ESI): calcd. for
C54H54Cl2O16Si10 [M + Na]+ 1332.04; found 1331.9689.
Supporting Information (see footnote on the first page of this arti-
cle): 1H NMR, 13C{1H} NMR, and 29Si{1H} NMR spectra;
HRMS (ESI) spectra; characterization data for 4–7 including crys-
tallographic data for trans-5.
Acknowledgments
This research was financially supported by the Thailand Research
Fund (MRG5580011), the Office of the Higher Education Com-
mission, Center of Excellence for Innovation in Chemistry
(PERCH-CIC), and the Nanotechnology Center (NANOTEC),
NSTDA, Ministry of Science and Technology, Thailand through
its program of Center of Excellence Network. The authors are very
thankful to Assoc. Prof. Dr. Nongnuj Muangsin for a discussion
of the single-crystal X-ray analysis.
[1] a) K. Yoshida, K. Ito, H. Oikawa, M. Yamahiro, Y. Morimoto,
K. Ohguma, K. Watanabe, N. Ootake, United States Patent
Application 2004, 20040068074; b) F. J. Feher, T. A. Bud-
zichowki, Organometallics 1991, 10, 2526; c) A. R. Bassindale,
M. Pourny, P. G. Taylor, M. B. Hursthouse, M. E. Light, An-
gew. Chem. 2003, 115, 3612; Angew. Chem. Int. Ed. 2003, 42,
3488; d) B. Marciniec, M. Dutkiewicz, H. Maciejewski, M. Ku-
bicki, Organometallics 2008, 27, 793; e) H. Liu, S. Kondo, R.
Tanaka, H. Oku, M. Unno, J. Organomet. Chem. 2008, 693,
1301; f) V. Ervithayasuporn, J. Abe, X. Wang, T. Matsushima,
H. Murata, Y. Kawakami, Tetrahedron 2010, 66, 9348; g) V.
Ervithayasuporn, X. Wang, B. Gacal, B. N. Gacal, Y. Yagci, Y.
Kawakami, J. Organomet. Chem. 2011, 696, 2193; h) X. Wang,
V. Ervithayasuporn, Y. Zhang, Y. Kawakami, Chem. Commun.
2011, 47, 1282; i) Y. Kawakami, React. Funct. Polym. 2007,
67, 1137; j) K. Yoshida, T. Hattori, N. Ootake, R. Tanaka, H.
Matsumoto, in: Silicon Based Polymers: Advances in Synthesis
and Supramolecular Organization (Eds.: F. Ganachaud, S.
Boileau, B. Boury), Springer, Berlin, 2008, p. 205–211; k) R. M.
Laine, M. F. Roll, Macromolecules 2011, 44, 1073.
[2] a) D. W. Lee, Y. Kawakami, Polym. J. 2007, 39, 230; b) V. Ervi-
thayasuporn, X. Wang, Y. Kawakami, Chem. Commun. 2009,
5130.
[3] a) M. Seino, T. Hayakawa, Y. Ishida, M. Kakimoto, Macromol-
ecules 2006, 39, 3473; b) S. Wu, T. Hayakawa, R. Kikuchi, S. J.
Grunzinger, M. Kakimoto, Macromolecules 2007, 40, 5698; c)
S. Wu, T. Hayakawa, M. Kakimoto, H. Oikiawa, Macromole-
cules 2008, 41, 3481; d) B. Seurer, V. Vij, T. Haddad, J. M.
1
1417.1489. Data for cis-5: H NMR (500 MHz, CDCl3): δ = 7.56–
7.18 (m, 40 H), 4.39 (oct., J = 6.1 Hz, 2 H), 3.41 (t, J = 6.8 Hz, 4
H), 1.90 (m, 4 H), 1.12 (d, J = 6.2 Hz, 12 H), 0.85 (m, 4 H) ppm.
13C{1H} NMR (125 MHz, CDCl3, TMS): δ = 134.91, 134.83,
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Mabry, A. Lee, Macromolecules 2010, 43, 9337; e) L. Wang, C.
Zhang, S. Zheng, J. Mater. Chem. 2011, 21, 19344.
a) M. A. Hoque, Y. Kakihana, S. Shinke, Y. Kawakami, Mac-
romolecules 2009, 42, 3309; b) M. Kohri, J. Matsui, A. Watan-
abe, T. Miyashita, Chem. Lett. 2010, 39, 1162.
[6] a) U. Dittmar, B. J. Hendan, U. Flrke, H. C. Marsmann, J. Or-
ganomet. Chem. 1995, 489, 185; b) M. Dutkiewicz, H. Macie-
jewski, B. Marciniec, Synthesis 2009, 12, 2019; c) V. Ervithayas-
uporn, T. Tomeechai, N. Takeda, M. Unno, A. Chaiyanurak-
kul, T. Osotchan, Organometallics 2011, 30, 4475; d) T. Jaroen-
tomeechai, P. Yingsukkamol, C. Phurat, E. Somsook, T. Osot-
chan, V. Ervithayasuporn, Inorg. Chem. 2012, 51, 12266.
[7] G. M. Sheldrick, Acta Crystallogr., Sect. A 2008, 64, 112–122.
Received: February 28, 2013
[4]
[5] a) A. C. Kucuk, J. Matsui, T. Miyashita, J. Colloid Interface
Sci. 2011, 355, 106; b) J. Espinas, J. D. A. Pelletier, E. Abou-
Hamad, L. Emsley, J.-M. Basset, Organometallics 2012, 31,
7610.
Published Online: May 29, 2013
Eur. J. Inorg. Chem. 2013, 3292–3296
3296
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