Synthetic application of silicates/silanolates and their hydrolyzed polysilanol siloxanes for polyhedral oligomeric silsesquioxanes (POSSs)

Article abstract of DOI:10.1002/hc.21373

Several types of silicate and their hydrolyzed polysilanols were applied to the synthesis of polyhedral oligomeric silsesquioxanes (POSSs). Silicate cubic octasilicate [Si₈O₂₀]^8? 5 was silylated with trimethylchlorosilane to yield the incompletely trimethylsilylated cubic octasilicate [Si₈O₂₀](SiMe₃)₇H 1b bearing one silanol in addition to the totally trimethylsilylated derivative [Si₈O₂₀](SiMe₃)₈ 1a. Further silylation of the monosilanol 1b with dimethylchlorosilane and α,ω-hydridochlorooctamethyltetrasiloxane resulted in the formation of POSSs 1c,d, which have hydrosilyl groups as elongated siloxane side chain. Attempts to generate an amino-substituted POSS via chloromethyldimethylsilylation of silicate 5 followed by reaction with amine as well as lithium amide failed. Amino-substitution was accomplished via the use of amine as a catalyst for the capping reaction of incompletely condensed trisilanol 10b with γ-aminopropyltrimethoxysilane affording mono amino-functionalized POSSs 2b,c in moderate yields. Another group of silanolates 7-9 was hydrolyzed with AcOH or HCl to give the corresponding cyclic polysilanol siloxanes 11a-c, respectively. Amine-catalyzed condensation of several of these polysilanol siloxanes 11a-c resulted in the formation of POSSs in high yields depending on the structure of substrates.

Full text of DOI:10.1002/hc.21373

Received: 4 November 2016
DOI: 10.1002/hc.21373
Revised: 24 April 2017
|
|
R E S E A R C H A R T I C L E
Synthetic application of silicates/silanolates and their hydrolyzed
polysilanol siloxanes for polyhedral oligomeric silsesquioxanes
(POSSs)
Yoshiteru Kawakami
Hirofumi Seino
Kazushi Ohtaki
Yoshio Kabe
|
|
|
Department of Chemistry, Faculty of
Science, Kanagawa University, Hiratsuka,
Japan
Abstract
Several types of silicate and their hydrolyzed polysilanols were applied to the synthe-
sis of polyhedral oligomeric silsesquioxanes (POSSs). Silicate cubic octasilicate
[Si8O20]8− 5 was silylated with trimethylchlorosilane to yield the incompletely tri-
methylsilylated cubic octasilicate [Si8O20](SiMe3)7H 1b bearing one silanol in addi-
tion to the totally trimethylsilylated derivative [Si8O20](SiMe3)8 1a. Further silylation
of the monosilanol 1b with dimethylchlorosilane and α,ω-hydridochlorooctamethylt
etrasiloxane resulted in the formation of POSSs 1c,d, which have hydrosilyl groups
as elongated siloxane side chain. Attempts to generate an amino-substituted POSS
via chloromethyldimethylsilylation of silicate 5 followed by reaction with amine as
well as lithium amide failed. Amino-substitution was accomplished via the use of
amine as a catalyst for the capping reaction of incompletely condensed trisilanol 10b
with γ-aminopropyltrimethoxysilane affording mono amino-functionalized POSSs
2b,c in moderate yields. Another group of silanolates 7-9 was hydrolyzed with AcOH
or HCl to give the corresponding cyclic polysilanol siloxanes 11a-c, respectively.
Amine-catalyzed condensation of several of these polysilanol siloxanes 11a-c re-
sulted in the formation of POSSs in high yields depending on the structure of
substrates.
Correspondence
Yoshio Kabe, Department of Chemistry,
Faculty of Science, Kanagawa University,
Hiratsuka, Japan.
Email: kabe@kanagawa-u.ac.jp
Funding information
Ministry of Education, Culture, Sports,
Science and Technology, Japan
of the organosilane, a mixture of POSSs results in moderate
1
INTRODUCTION
|
yield in which octasilsesquioxane 2 is the major component
Silylated cubic octasilicate 1 and polyhedral oligomeric
silsesquioxanes (POSSs) [RSiO1.5]n (n=6-12) 2-4[1] have
attracted considerable interest as models for the silica sur-
face,[2a] for silica-supported transition metal catalysts,[2b] and
also as precursors for hybrid inorganic-organic materials, eg,
liquid crystals,[3a,b] dendrimers,[3c–i] porous solids,[3j–l] and
composite materials.[3m] The traditional primary synthetic
route to POSS has involved hydrolytic condensation of tri-
functional organosilane RSiX3 under acidic or basic condi-
tions.[4] Depending on the bulkiness of the substituent (R)
(Scheme 1).
An alternative route to an cubic octasilicate 1 has been
reported involving the silylation of a tetramethylammonium
salt of cubic octasilicate [Si8O20]8−[(CH3)4N]+ 5.[5] The
8
cubic octasilicate cage [Si8O20]8− is easily formed by the
treatment of tetraethoxysilane with tetramethylammonium
ions in mixed organic solvents.[5a,d,f,h] Further modification of
the silyl groups at each corner of the cubic octasilicate cage
[Si8O20]8− core has provided versatile and selective synthesis
of cubic octasilicate derivatives.[5j-m]
Recently, incompletely condensed trisilanolates
[R7Si7O9](ONa)3 6 have become available as new type
of silicate, which are easily prepared compared to the
Contract grant sponsor: Ministry of Education, Culture, Sports, Science and
Technology, Japan.
|
Heteroatom Chemistry. 2017;28:e21373.
https://doi.org/10.1002/hc.21373
wileyonlinelibrary.com/journal/hc
© 2017 Wiley Periodicals, Inc.
1 of 12

2 of 12
KAWAKAMI et Al.
|
SCHEME 1 Synthetic routes of polyhedral oligomeric silsesquioxane (POSS) starting from several types of silicates and silanolates
corresponding
incompletely
condensed
trisilanols
2
RESULTS AND DISCUSSION
Incomplete trimethylsilylation of
|
[R7Si7O9](OH)3 10.[6] In spite of relatively bulkier substitu-
ents needed for trisilanol [R7Si7O9](OH)3, the capping reac-
tion of trisilanol was widely applied for syntheses of POSS
derivatives.[7]
2.1
|
silicate 5
Silicate 5 bearing the cubic octasilicate cage [Si8O20]8− is only
stable in alkaline aqueous and organic solution in the presence
of tetramethylammonium ion. The cage structure is known to
be stable against cleavage in the reaction of trimethylsilation
on oxyanions at each corner to yield the compound [Si8O20]
(SiMe3)8-nHn (n=0-3) (Scheme 2). While incomplete silylation
of silicate 5 with trimethyl-, dimethylhydro-, and dimethylvi-
nylchlorosilane have been investigated,[5b,e,f] isolation of incom-
pletely silylated compounds was not accomplished so far. Gel
permeation chromatography (GPC) of a mixture resulted from
the reaction of 5 with trimethylchlorosilane in a 1:16 molar ratio
showedthat, besidesthetotallytrimethylsilylated[Si8O20]8− cage
[Si8O20](SiMe3)8 1a (1.9%), the incompletely trimethylsilylated
derivatives of the [Si8O20]8− cage with one silanol group [Si8O20]
(SiMe3)7H 1b (8.2%)[5f,10] and the mixed silylated compounds
[Si8O20](SiMe3)6H2 (12.4%) and [Si8O20](SiMe3)5H3 (5.3%)
were formed (Table 1). The structure of the totally trimethylsi-
lylated compound 1a was assigned by X-ray crystallography.[11]
Changing the molar ratio of 5 and trimethylchlorosilane to 1:24
Another type of silanolate has been prepared by the
hydrolysis of phenyltrialkoxysilane with an aqueous-
alcoholic solution of NaOH both in the presence or absence
of copper chloride to yield Na4[RSi(O)O]4 7 (R=Ph),
Na4Cu4[(RSi(O)O)6]2 8 (R=Ph) or Na4Cu4[RSi(O)O]12
9
(R=Ph).[8] Although stereo regular cyclic polysilanol silox-
anes 11 (n=4, 6, and 12) have been obtained by hydrolysis
of these silanolates 7-9 with acetic acid[8f] or hydrochloric
acid,[8d] the synthetic application of silicates 7-9 as well as
cyclic polysilanol siloxanes 11 (n=4, 6, and 12) are thus
far limited. However, as was described in our prelimi-
nary report, amine-catalyzed hydrolytic condensation of
the cyclic polysilanol siloxanes 11 (n=6 and 12) provides
higher POSS derivatives.[9]
These findings prompted us to study the synthetic applica-
tions of silicates 5-9 as well as cyclic polysilanol siloxanes 11
(n=4, 6, and 12) in the production of POSS derivatives, and
herein are reported the full details of the results.

KAWAKAMI et Al.
3 of 12
|
SCHEME 2 Incomplete
trimethylsilylation of silicate 5 and silylation
of incompletely trimethylsilylated silicate 1b
TABLE 1 Yields of incompletely silylated silicate by partial
silylation of 5
Yield of Si8O20(SiMe3)8-nHn (n=0-3) (%)
Molar ratio of
5 and Me3SiCl
n=0 (1a)
n=1 (1b)
n=2
n=3
1:16
1:24
1:32
1.9
38.0
53.3
8.2
30.7
12.6
12.4
5.3
a
11.4
a
a
aNot isolated by GPC.
and 1:32, the yields of incompletely trimethylsilylated com-
pounds with one silanol group 1b increased to 30.7% and 12.6%,
respectively. The 1H NMR spectrum of 1b shows three Me3Si
group protons (0.171, 0.181, and 0.183) in a 3:3:1 ratio, along
with one SiOH proton (6.656 ppm). The Me3Si protons are rea-
sonably assigned to the three trimethylsiloxy groups neighbor-
ing silanol, the three distant groups and one opposite group of
the C3v silicate cage (Figure 1).
FIGURE 1 Equivalent positions (X-Z) around T8 silsesquioxane
cages in relation to Si-R mono substitution T is abbreviation of
RSiO3/2, XSiO3/2, YSiO3/2 and ZSiO3/2, moiety and RX3Y3Z(SiO3/2 8
)
correspond to T8
Further silylation of the silanol functionality in 1b were
accomplished with dimethylchlorosilane or α,ω-hydridoch
lorooctamethyltetrasiloxane (Scheme 2). The silylation of
the mono silanol compound 1b with dimethylchlorosilane
yielded the corresponding silylated product 1c in 88.6%
yield.[5g] The use of α,ω-hydridochlorooctamethyltetrasilox
ane as the silylation reagent for siloxane chain elongation[12]
afforded 1d having the silicate cage with a siloxane side chain
in 41% yield. To the best of our knowledge, this is the first
example of the siloxane chain elongation of monosilanol
derivatives of the cubic octasilicate cage [Si8O20]8−.
2.2
Chloromethylsilylation of silicate
|
5 and amination
Silylation of 5 in H2O/MeOH with chloromethyldimethyl-
chlorosilane in dimethoxypropane (DMOP)/THF yielded

4 of 12
KAWAKAMI et Al.
|
SCHEME 3 Chloromethylsilylation of silicate 5 followed by amination and amino-substituted POSSs derived from trisilanol derivatives
10a,b
the totally chloromethyldimethylsilylated derivative 1e in
42.4% yield (Scheme 3). The synthesis of 1e by mixing 5 in
H2O/DMSO with bis(chloromethyl)tetramethyldisiloxane
in DMOP/THF was previously reported.[5h] In these cases,
dimethoxypropane was also employed as a trapping reagent
for water, which prevents excess consumption of chlorome-
thyldimethylchlorosilane. The silylated compound 1e bears
a reactive chloromethylsilyl functional group, which should
allow the compound to serve as a precursor for amino-
substituted POSSs.[3c,d,g,h] However, nucleophilic substitu-
tion with diethylamine resulted in the recovery of the starting
material, while lithium diethylamide destroyed the silicate
cage (Scheme 3).
the corresponding phenyl-substituted trisilanol derivative
[Ph7Si7O9](OH)3 10a in 94.2% yield (Scheme 3). Trisilanol
10a was purified by recrystallization from a mixed solvent of
chloroform and hexane. The X-ray analysis of 10a showed
two independent molecules (Figure 2). Both molecules
formed trisilanol dimers upon hydrogen bonds as similarly
as other trisilanols.[7] However, siloxane backbone of 10a
has C1 symmetry instead of C3v symmetry due to packing of
the phenyl substituents.
The hydrolytic condensation of γ-aminopropyltrimethox-
ysilane in MeOH/THF is known to provide the ammonium-
+
substituted
POSS,
[Si8O12](CH2CH2CH2NH3 Cl−)8,
which is surprisingly difficult to be neutralized without
destroying the POSS cage.[3c,d] We attempted syntheses of
aminopropyl-substituted POSSs from a phenyl-substituted
trisilanol derivative 10a with two γ-aminopropyltrimethox-
ysilanes ((MeO)3SiCH2CH2CH2NRMe, R=Me, H) in the
presence of triethylamine. However, these efforts failed
and afforded complex condensates. It seems that conden-
sation by the SiO− anion occurred on the electrophilic
phenyl-substituted siloxane rather than the alkyl-substituted
alkoxysilanes. In contrast, the use of commercially avail-
able [i-Bu7Si7O9](OH)3 10b as an alkyl-substituted tris-
ilanol derivative instead of 10a gave the corresponding
fully condensed POSS 2b and 2c with a γ-aminopropyl
group in 80.2% and 64.7% yield, respectively (Scheme 3).
Spectroscopic data of these compounds revealed the struc-
tures of 2b and 2c to have C3v symmetry. In comparison
2.3
Syntheses of aminopropyl-substituted
|
POSSs from trisilanol derivatives 10 and
trimethoxysilanes
It is known that the reaction of an incompletely condensed
silsesquioxane, eg, a trisilanol ([R7Si7O9](OH)3; 10) sub-
stituted by bulky alkyl groups, with trichlorosilanes is a
useful synthetic route to mono-functionalized, fully con-
densed silsesquioxanes. These trisilanols have been syn-
thesized via direct hydrolysis of the corresponding trichlo-
rosilanes. Recently, a related trisilanolate [Ph7Si7O9](ONa)3
6 synthesized by the hydrolysis of phenyltrimethoxysi-
lanes with sodium hydroxide was reported.[6] Treatment
of this silanolate with dilute hydrochloric acid afforded

KAWAKAMI et Al.
5 of 12
|
FIGURE 2 X-ray molecular structures
of 10a showing 30% probability ellipsoids.
All hydrogen atoms except silanol are
omitted for clarity
SCHEME 4 POSSs derived from silanolate 7 via polysilanol siloxane 11a
with the literature,[3c,d] mono functionalization of amino
propyl groups seems to reduce the typical enhancement of
the base-catalyzed decomposition of POSS cages. To the
best of our knowledge, the formation of fully condensed
POSS cages by amine-catalyzed reactions of trisilanol and
trialkoxysilanes is the first example.
effective at dehydrating polysilanols for POSS synthesis
in DMSO or THF.[13a] The condensation of 11a or silan-
[14]
etriol PhSi(OH)3
using triethylamine, butylamine, and
DCC as condensation regents were investigated for com-
parison (Scheme 4). After 2 days at reflux, 11a condensed
in the presence of triethylamine or butylamine to give 2a in
36.8%/38.8% yield and 3a in 19.6%/18.9% yield (Table 2:
Run 5,6), while 11a treated with DCC gave a mixture of 2a
and 3a in 24.5% and 12.0% yields, respectively (Table 2: Run
4). The spectroscopic data and X-ray structures of 2a and 3a
match those of published results.[15a,b] In addition to 2a and
3a, a small amount of 4a was also formed in all cases. F−-
catalyzed rearrangement of 2a and 3a has been reported to
yield 4a in moderate yield depending on solvent.[13e] X-ray
structure of 4a[15c] without solvent was successfully obtained
as shown in Figure 3. When using silanetriol PhSi(OH)3,
the yields of 3a became lower (Table 2: Run 1-3). More
2.4
POSSs derived from silanolate 7 via
|
polysilanol siloxane 11a
According to the literature method,[8a,d,f] silanolate 7 can
be prepared via hydrolysis of phenyltri(butoxy)silane in
1-butanol or phenyltrimethoxysilane in 2-propanol in the
presence of an equimolar amount of NaOH. 7 can be sub-
sequently treated with dilute acetic acid to yield all-cis
cyclic polysilanol siloxane 11a [PhSi(O)OH]4 (Scheme 4).
Dicyclohexylcarbodiimide (DCC) was reported to be

6 of 12
KAWAKAMI et Al.
|
TABLE 2 Dehydrative condensation of cyclic polysilanols (11a, 11b and 11c) and PhSi(OH)3
Yield of fully condensed cages (%)
Product ratiob
Run
Silanol
Condensation reagentsa
PhT8 (2a)c
PhT12 (3a)c
PhT10 (4a)c
(2a:3a)
1
2
3
4
5
6
7
8
9
10
PhSi(OH)3
DCC
Et3N
BuNH2
DCC
Et3N
BuNH2
Et3N
BuNH2
Et3N
3.3
22.5
32.8
24.5
36.8
38.8
65.8
18.6
6.5
5.3
0.3
9.4
12.0
19.6
18.9
9.5
1.7
15.5
55.7
8.7
6.7
2.6
8.1
4.7
2.3
1.9
1.7
6.6
4.1
38 : 62
99 : 1
78 : 22
67 : 33
65 : 35
67 : 33
87 : 13
92 : 8
11a (n=4)
11b (n=6)
11c (n=12)
30 : 70
10 : 90
BuNH2
5.9
DCC, dicyclohexylcarbodiimide.
aConditions of hydrolytic condensation: acetone reflux 2 d, conditions for Run 1 and 4: THF reflux 2 d.
bProduct ratio based on Si atom.
cT is abbreviation of RSiO3/2 moiety and (PhSiO3/2)n correspond to PhTn.
2.5
POSSs derived from silanolates 8 and 9
|
via polysilanol siloxanes 11b,c
The hydrolysis of phenyltrialkoxysilanes in NaOH/
ROH-water leads to in situ generation of the intermediate
[PhSi(ONa)(OH)OR], which subsequently undergoes an
exchange reaction with copper chloride to yield silanolates
8 and 9.[8d] Selective formations of silanolates 8 and 9 and
their hydrolyzed polysilanol siloxanes 11b and 11c (n=6
and 12) were reported in the literature.[8d] However, the
silanolate 8 was formed always together with silanolate 9.
After trimethylsilylation for a mixture of silanolates 8 and
9, the trimethylsilylated products 12b and 12c exhibited one
singlet for Me3Si proton (0.22 ppm) for the all-cis structure
of 12b (n=6) and two singlets for Me3Si protons (−0.31 and
−0.01 ppm) in a 2:1 ratio for the tris-cis-tris-trans struc-
1
ture of 12c (n=12) in the H NMR spectra (Figure 4a). The
1
61:39 ratio of 12b and 12c was determined by H NMR of
trimethylsilylated products. Furthermore, the stereochem-
istry of the cyclic polysilanol siloxanes 11b and 11c (n=6
and 12) was also reported to be retained.[8d] Only to confirm
stereochemical integrity, several fractional recrystallization
of silanolates 8 and 9 using EtOH/benzene were carried out,
each fraction of which was hydrolyzed with HCl to afford
polysilanol siloxanes 11b and 11c (n=6 and 12) in pure
forms, respectively. Similar to 12b and 12c, the cyclic polysi-
lanol siloxane 11b (n=6) showed one set of Ph protons (7.15,
7.31, and 7.59 ppm) along with one SiOH proton (6.44 ppm),
while 11c (n=12) showed two sets of Ph protons (7.10, 7.15,
7.31, 7.34, 7.55, and 7.68 ppm) in a 2:1 ratio along with two
SiOH protons (6.79 and 6.84 ppm; Figure 4b, c).
FIGURE 3 X-ray molecular structures of (PhSiO3/2)10 4a
showing 30% probability ellipsoids. All hydrogen atoms are omitted
for clarity
stronger bases such as benzyltrimethylammonium hydroxide
or tetrabutylammonium fluoride as a catalyst were reported
to increase the yields of 2a without 3a.[13c] Although weak
base makes the yield of 2a and 3a lower, it is noteworthy that
the combination of 11a and amine/DCC shows a tendency
toward preparation of the higher cage 3a (Table 2: Run 4-6).
This is probably because amine/DCC does not cleave the
POSS cages once formed (Scheme 5).
Hydrolysis of the mixture of 8 and 9 afforded the mixture
of 11b and 11c. These polysilanol siloxanes were successfully

KAWAKAMI et Al.
7 of 12
|
SCHEME 5 POSSs derived from silanolates 8 and 9 via polysilanol siloxanes 11b,c
separated by silica gel column chromatography with THF:
3
CONCLUSIONS
|
toluene (1:3) as the eluent. Thus, cyclic polysilanol silox-
anes 11b and 11c (n=6 and 12) were employed as starting
compounds for POSSs. For amines as condensation catalysts,
Et3N and BuNH2 were used because DCC was not effective
to the formation of fully condensed cages. The cyclic poly-
silanol siloxane 11b (n=6) in acetone with Et3N or BuNH2,
after 2 days of refluxing, provided a precipitate mixture of
2a and 3a in 75.3% and 20.3% combined yields, respec-
In summary, we have demonstrated that silicates and
silanolates 5-9 and their hydrolyzed polysilanol siloxanes
10 and 11 can be applied as synthetic precursor for POSSs.
Silylation of incompletely silylated silicate 1b and amine-
catalyzed condensation of trisilanol 10b afforded mono-
functionalized POSSs, 1c,d, and 2b,c. Compared to phenylsi-
lanetriol, cyclic polysilanol siloxanes 11a,b,c tend to provide
higher cage compounds, depending on the structure of sub-
strate and amine used as a catalyst.
1
tively (87:13 and 92:8 ratio of 2a:3a by H NMR) (Table 2:
Run 7,8). When 11c (n=12) was employed, the ratios was
reversed (30:70 and 10:90 ratio of 2a:3a) in 22.0% and 61.6%
combined yields, respectively (Table 2: Run 9,10). It is note-
worthy that combination of the cyclic polysilanol siloxanes
11c (n=12) and amine selectively produces the higher cage
POSS 3a (Table 2: Run 9,10). This is probably because poly-
silanol siloxanes 11c (n=12) contains the same units of silox-
ane frameworks of higher cage 3a (Figure 5). And amine is
effective for condensation without the breakdown of the cage
once formed.
4
4.1
EXPERIMENTAL
General data
|
|
The 1H, 13C, and 29Si NMR spectra were recorded on a JEOL
JNM-ECP500 operating at 500, 125, or 100 MHz, respec-
tively, and a JEOL JNM-ECZ600 operating at 600, 150 or
120 MHz, respectively. Mass spectra were recorded on a

8 of 12
KAWAKAMI et Al.
|
4.3
Trimethylsilylation of silicate 5
|
A solution of [Si8O20]8−(Me4N+)8 5 was prepared by addi-
tion of Si(OEt)4 (4.48 mL, 20.1 mmol) and 10 mL MeOH
into Me4N+OH−·5H2O (3.62 g, 20 mmol), 10 mL MeOH, and
1.8 mLH2O(100 mmol).Themixturewasstirredfor24 hours,[5]
and then added dropwise into a solution of Me3SiCl (7.59 mL,
60.0 mmol) in 100 mL THF over 5 minutes. After stirring for
1 hour, the reaction mixture was extracted with 100 mL hexane
and 10 mL H2O. The organic layer was separated and concen-
trated. The residue was dissolved in hexane and filtered. After
removed of solvent, a mixture of trimethylsilylated derivatives
[Si8O20](SiMe3)8-nHn (n=0-3) was obtained.
4.4
Isolation of monosilanol functionalized
|
silsesquioxane 1b
In order to remove the totally silylated derivative 1a
(n=0), the incompletely silylated derivatives (n=1-3)
were extracted with MeOH, and concentrated. The residue
was recrystallized from hexane at −78°C. The recrystal-
lized crude 1b (n=1) was purified by GPC to give 0.811 g
(30.7%) of 1b. Colorless solid; m.p. 153°C; 1H NMR
(500 MHz, acetone-d6): δ 0.171 (s, SiMe3, 27H), 0.181 (s,
SiMe3, 27H), 0.183 (s, SiMe3, 9H), 6.656 (s, SiOH, 1H);
13C NMR (125 MHz, acetone-d6): δ 1.29 (SiCH3), 1.32
(SiCH3), 1.35 (SiCH3); 29Si NMR (100 MHz, acetone-d6):
δ −109.00 (SiO4/2), −108.87 (SiO4/2), −108.77 (SiO4/2),
−101.17 (SiO3/2OH), 12.66 (SiMe3), 12.82 (SiMe3);
HRMS (ESI) m/z calcd for C21H64NaO20Si15 ([M+Na]+),
1079.0428, found 1079.0407.
FIGURE 4 1H-NMR of trimethylsilyl range 12b and 12c (a) and
aromatic ranges of 11b (n=6) (b) and 11c (n=12) (c)
JEOL SX102A, a JEOL JMS-AX505H, and a Shimadzu
AXIMA-CFR. GPLC (gel permeation liquid chromatogra-
phy) was performed on a LC-908 (Japan Analytical Industry,
Co., Ltd.) equipped with JAIGEL 1H and 2H columns (elu-
ent: toluene). CHN elemental analyses were carried out with
a Perkin–Elmer 2400 CHNS Elemental Analyzer II.
4.5
Analyses of di- and trisilanol
|
derivatives [Si8O20](SiMe3)8-nHn (n=2,3)
4.2
Materials
|
After removing 1a and 1b, [Si8O20](SiMe3)8-nHn (n=2,3)
were separated from residue by GPC. Both compounds
consisted of mixtures of isomers. [Si8O20](SiMe3)6H2:
Colorless solid; 1H NMR (500 MHz, Acetone-d6): δ 0.158-
0.181 (m, SiMe3, 54H), 6.639-6.664 (m, SiOH, 2H); 13C
NMR (125 MHz, Acetone-d6): δ 1.25-1.36 (SiCH3); ESI
MS m/z 1007 ([M+Na]+). [Si8O20](SiMe3)5H3: Colorless
solid; 1H NMR (500 MHz, acetone-d6): δ 0.158-0.181
(m, SiMe3, 45H), 6.599-6.664 (m, SiOH, 3H); 13C NMR
(125 MHz, acetone-d6): δ 1.25-1.36 (SiCH3); ESI MS m/z
935 ([M+Na]+).
All solvents and reagents were purified using standard proce-
dures. [Si8O20]8−[(CH3)4N]+8 5,[5f] Cl(SiMe2O)3SiMe2H,[12b]
[Si8O20](Me2SiCH2Cl)8 1e,[5i] [Ph7Si7O9](ONa)3 6,[6]
PhSi(OH)3,[14] Na4[PhSi(O)O]4 7,[8f] Na4Cu4[(PhSi(O)O)6]2
8,[8d] Na4Cu4[PhSi(O)O]12 9,[8d] [PhSi(O)OH]4 11a,[8d]
all-cis-[PhSi(O)OH]6 11b,[8d] tris-cis-tris-trans-[PhSi(O)
OH]12 11c,[8d] all-cis-[PhSi(O)OSiMe3]6 12b,[8d] and tris-
cis-tris-trans-[PhSi(O)OSiMe3]12 12c[8d] were prepared by
published procedure. Trisilanol [i-Bu7Si7O9](OH)3 10b,
γ-dimethylamino, and methylaminopropyltrimethoxysilane,
PhSi(OMe)3, PhSi(OEt)3 were purchased from Aldrich.
FIGURE 5 Transformation from 11c
to 3a

KAWAKAMI et Al.
9 of 12
|
1M aqueous HCl. Then, 45 mL of chloroform was added,
and the organic layer was washed with 20 mL of water.
Evaporation of the solvent from the mixture gave 2.63 g
4.6
Silylation of [Si8O20](SiMe3)7H 1b with
|
dimethylchlorosilane
1
[Si8O20](SiMe3)7H 1b (0.635 g, 0.600 mmol) in 10 mL THF
was added dropwise to a mixture of Me2SiHCl (0.133 mL,
1.20 mmol) and dry pyridine (97.0 μL, 1.20 mmol) in 10 mL
THF and stirred overnight. The solvent, excess Me2SiHCl
and pyridine were removed under reduced pressure to yield
a white solid. The solid was extracted with hexane and fil-
tered to remove the pyridinium salt giving 0.593 g (88.6%)
of [Si8O20](SiMe3)7(SiMe2H) (1c). Colorless crystal; m.p.
(2.83 mmol) of 10a (94.2% yield). White solid; H NMR
(500 MHz, acetone-d6): δ 6.94 (s, SiOH, 3H), 7.43-7.37
(m, Ph, 14H), 7.43-7.37 (m, Ph, 6H), 7.46 (t, J=7.5 Hz,
Ph, 1H), 7.57 (d, J=6.8 Hz, Ph, 6H), 7.69 (d, J=6.8 Hz,
Ph, 6H), 7.72 (d, J=6.8 Hz, Ph, 2H); 13C NMR (125 MHz,
Acetone-d6): δ 128.61 (CH), 128.63 (CH), 129.08 (CH),
131.18 (C), 131.30 (CH), 131.49 (CH), 131.72 (C), 131.83
(CH), 133.04 (C), 134.68 (CH), 134.71 (CH), 134.82 (CH);
29Si NMR (100 MHz, acetone-d6): δ −78.45 (PhSiO3/2),
−77.17 (PhSiO3/2), −69.75 (PhSi(O)OH); ESI MS m/z 953
([M+Na]+).
1
218°C; H NMR (500 MHz, CDCl3): δ 0.152 (s, SiMe3,
36H), 0.154 (s, SiMe3, 27H), 0.247 (d, J=2.7 Hz, SiMe2,
6H), 4.738 (sept, J=2.7 Hz, SiH, 1H); 13C NMR (125 MHz,
CDCl3): δ 0.11 (SiCH3), 1.22 (SiCH3), 1.24 (SiCH3); 29Si
(100 MHz, CDCl3): δ −108.97 (SiO4/2), −108.88 (SiO4/2),
−108.55 (SiO4/2), −2.08 (SiMe2H), 12.56 (SiMe3), 12.68
(SiMe3); MALDI-TOF MS m/z: 1153 ([M+K]+); Anal.
Calcd for C23H70O20Si16 (1116.16): C 24.75, H 6.32. Found:
C 25.01, H 6.43.
4.9
Preparation of [Si8O12](i-
|
Bu)7(CH2CH2CH2NMe2) 2b
A mixture of [i-Bu7Si7O9](OH)3 10b (1.58 g, 2.00 mmol),
dimethylaminopropyltrimethoxysilane (0.415 g, 2.00 mmol),
and Et3N (0.139 mL, 1.00 mmol) was refluxed for 48 hours.
A white powder was precipitated and was filtered to give
1.45 g (80.2%) of 2b. Colorless crystal; Sublimation point
4.7
Silylation of [Si8O20](SiMe3)7H 1b with
|
α,ω-hydridochlorooctamethyltetrasiloxane
1
157°C; H-NMR (500 MHz, C6D6): δ 0.78-0.82 (m, CH2,
[Si8O20](SiMe3)7H 1b (0.164 g, 0.155 mmol) in 10 mL
THF was added dropwise to a mixture of α,ω-hydridochlo
rooctamethyltetrasiloxane Cl(SiMe2O)3SiMe2H (0.493 mL,
1.55 mmol) (prepared by the activated carbon-catalyzed ring
opening reaction of (SiMe2O)3 with Me2SiHCl,[12b]) and
dry pyridine (0.125 mL, 1.55 mmol) in 10 mL THF. After
stirring overnight, the solvent, excess Cl(SiMe2O)3SiMe2H
(88°C/10 mm Hg) and pyridine were removed under reduced
pressure to yield a white solid. The solid was extracted with
hexane and filtered to remove the pyridinium salt giving the
crude product. This crude product was purified by GPC, yield-
ing 85.0 mg (41.0%) of [Si8O20](SiMe3)7(SiMe2O)3SiMe2H
1d. Colorless solid; m.p. 77°C; 1H NMR (500 MHz, CDCl3):
δ 0.073 (s, SiMe2, 6H), 0.100 (s, SiMe2, 6H), 0.135 (s,
SiMe2, 6H), 0.144 (s, SiMe3, 27H) 0.148 (s, SiMe3, 27H),
0.152 (s, SiMe3, 9H), 0.188 (d, J=2.7 Hz, SiMe2, 6H), 4.705
(sept, J=2.7 Hz, SiH, 1H); 13C NMR (125 MHz, CDCl3):
δ 0.49 (SiCH3), 0.68 (SiCH3), 0.84 (SiCH3), 0.96 (SiCH3),
1.23 (SiCH3); 29Si NMR (100 MHz, acetone-d6): δ −108.95
(SiO4/2), −108.90 (SiO4/2), −108.86 (SiO4/2), −21.95
(SiMe2), −21.86 (SiMe2), −20.24 (SiMe2), −2.09 (SiMe2H),
12.54 (SiMe3), 12.67 (SiMe3); MALDI-TOF MS m/z: 1375
([M+K]+); Anal. Calcd for C29H88O23Si19 (1338.62): C
26.02, H 6.63. Found: C 25.99, H 6.66.
14H), 0.88 (t, J=8.2 Hz, CH2, 2H), 1.04-1.08 (m, CH2, 42H),
1.77 (q, J=7.6 Hz, CH2, 2H), 2.01-2.10 (m, CH, 7H), 2.12 (s,
CH3, 6H), 2.24 (t, J=7.0 Hz, CH2, 2H); 13C-NMR (125 MHz,
C6D6): δ 10.0 (CH2), 21.5 (CH2), 23.0 (CH2), 24.4 (CH),
25.9 (CH3), 25.9 (CH3), 45.5 (CH3), 62.5 (CH2); 29Si-NMR
(100 MHz, C6D6): δ −67.1 (i-BuSiO3/2), −66.9 (i-BuSiO3/2),
−65.9 (Me2N(CH2)3SiO3/2); MALDI-TOF MS m/z: 902
([M+H]+); Anal. Calcd for C33H75NO12Si8 (902.63): C 43.91,
H 8.38, N 1.55. Found: C 43.67, H 8.72, N 1.51.
4.10
Preparation of [Si8O12](i-
|
Bu)7(CH2CH2CH2NHMe) 2c
A mixture of [i-Bu7Si7O9](OH)3 10b (1.58 g, 2.00 mmol),
methylaminopropyltrimethoxysilane (0.387 g, 2.00 mmol),
and Et3N (0.139 mL, 1.00 mmol) was refluxed for 48 hours.
A white powder was precipitated and was filtered to give
1.15 g (64.7%) of 2c. Colorless crystal; Sublimation point
1
192°C; H-NMR (500 MHz, C6D6): δ 0.78-0.83 (m, CH2,
14H), 0.86 (t, J=8.2 Hz, CH2, 2H), 1.04-1.08 (m, CH2,
42H), 1.73 (q, J=7.1 Hz, CH2, 2H), 2.01-2.10 (m, CH, 7H),
2.26 (s, CH3, 6H), 2.50 (t, J=7.0 Hz, CH2, 2H); 13C-NMR
(125 MHz, C6D6): δ 10.0 (CH2), 23.0 (CH2), 23.0 (CH2),
23.5 (CH2), 24.0 (CH), 25.9 (CH3), 25.9 (CH3), 36.4 (CH3),
54.8 (CH2); 29Si-NMR (100 MHz, C6D6): δ −67.1 (i-
BuSiO3/2), −66.9 (i-BuSiO3/2), −66.0 (MeNH(CH2)3SiO3/2);
MALDI-TOF MS m/z: 888 ([M+H]+); Anal. Calcd for
C32H73NO12Si8 (888.61): C 43.25, H 8.28, N 1.58. Found:
C 43.17, H 8.62, N 1.62.
4.8
Preparation of [Ph7Si7O9](OH)3 10a
|
[Ph7Si7O9](ONa)3 6 (2.99 g, 3.00 mmol) was stirred at room
temperature for 5 minute in a 90 mL of THF and 10 mL of

10 of 12
KAWAKAMI et Al.
|
Then, (PhSiO3/2)8 was eluted with CH2Cl2 and evaporated
4.11
Synthesis of [PhSi(O)OH]4 11a
|
1
to give (PhSiO3/2)8·toluene as a white solid. 2a: H-NMR
Na4[PhSi(O)O]4 (42.1 g, 47.8 mmol calculated from
Na4[PhSi(O)O]4·4(2-propanol)) was added to a mixture of
0.5 mol L−1 AcOH aq. (400 mL) and THF (600 mL) over
ice bath. The reaction mixture was stirred for 10 minute and
then added a 400 mL of Et2O. The reaction mixture was sepa-
rated with twice of 100 mL of water and 100 mL of deion-
ized water. The organic phase was evaporated until solution
volume reduced to ca. 100 mL and then added 400 mL of
hexane to precipitate the product. The mixture was further
evaporated until solution volume reduced to ca. 100 mL and
then filtrated by suction filtration and washed three times
with 20 mL of hexane. The resulted white solid was stirred
under reduced pressure (0.1 mm Hg, 4 hours) to remove
residual organic solvent and dried over CaCl2 for 2 days
to give [PhSi(O)OH]4 11a (20.8 g, 37.7 mmol, 75.4%) as a
white powder.
(500 MHz, CD2Cl2): δ 7.39 (t, J=7.2 Hz, Ph, 16H), 7.47
(t, J=7.5 Hz, Ph, 8H), 7.77 (d, J=6.8 Hz, Ph, 16H); 13C-
NMR (125 MHz, CD2Cl2): δ 127.7 (CH), 129.8 (C), 130.6
(CH), 133.7 (CH); 29Si-NMR (100 MHz, CD2Cl2): δ −78.3
(PhSiO3/2); MALDI-TOF MS m/z: 1055 ([M+Na]+). 3a: 1H-
NMR (500 MHz, CD2Cl2): δ 7.16 (t, J=7.6 Hz, 16H), 7.28
(t, J=7.6 Hz, 8H), 7.32 (t, J=7.6 Hz, 8H), 7.40 (t, J=7.6 Hz,
4H), 7.49 (d, J=6.7 Hz, 16H), 7.63 (d, J=6.7 Hz, 8H); 13C-
NMR (125 MHz, CD2Cl2): δ 128.0 (CH), 128.2 (CH), 130.8
(CH), 131.0 (CH), 131.2 (C), 131.4 (CH), 134.4 (C), 134.5
(CH); MALDI-TOF MS m/z: 1571 ([M+Na]+).
To the filtrate small portions of oxalic acid (0.900 g,
10.0 mmol or 0.450 g, 5.00 mmol) was added separately to
quench the excess DCC and stirred for 30 minute at room
temperature. The solution was evaporated and separated with
CH2Cl2 and water. The organic layer was dried over Na2SO4,
and then evaporated to afford an oily solid. The mixture was
separated by silica gel short column chromatography with
hexane: toluene (1:1) to afford (PhSiO3/2)10 4a as a white solid.
4a was recrystallized from CH2Cl2 to obtain crystals suitable
4.12
Synthesis and separation of [PhSi(O)
|
OH]n (n=6, 12) 11b,c
for X-ray analysis. (PhSiO3/2 10
)
4a: 1H-NMR (600 MHz,
A mixture of Na4Cu4{[PhSi(O)O]6}2 and Na4Cu4[PhSi(O)
O]12 (10.9 g, 5.00 mmol calculated from Na4Cu4[PhSi(O)
O]12·4EtOH) in 2:1 solution of benzene and EtOH 150 mL
was added dropwise to 2.4 mol L−1 HCl aq. (150 mL)
for 5 minute at 5°C. The reaction mixture was stirred for
10 minute and then 1.5 L of cold water was added. The reac-
tion mixture was filtrated by suction filtration and washed
three times with 50 mL of cold water and three times with
20 mL of benzene and dried over CaCl2 for 2 days to give
the mixture of [PhSi(O)OH]6 11b and [PhSi(O)OH]12 11c
as a white solid. The crude mixture was separated by silica
gel column chromatography with THF: toluene (1:3) (Silica
gel column was washed with THF until elute solvent was
changed to transparent prior use. [PhSi(O)OH]12: Rf 0.58,
[PhSi(O)OH]6: Rf 0.29) to afford [PhSi(O)OH]6 11b (2.45 g,
2.96 mmol, 29.6%) as a white needle and [PhSi(O)OH]12 11c
(3.27 g, 1.97 mmol, 39.4%) as a white solid.
CDCl3): δ 7.25 (t, J=7.6 Hz, 20H), 7.38 (t, J=7.4 Hz, 10H),
7.61 (d, J=7.4 Hz, 20H); 13C-NMR (150 MHz, CDCl3): δ
127.7 (CH), 130.5 (CH), 130.6 (C), 134.2 (CH); 29Si-NMR
(120 MHz, CDCl3): δ −79.4 (PhSiO3/2); MALDI-TOF MS
m/z: 1313 ([M+Na]+).
4.14
Condensation of
|
PhSi(OH)3 and [PhSi(O)OH]n (n=4, 6 and 12)
11a-c using amines
A mixture of PhSi(OH)3 (1.56 g, 10.0 mmol based on Si) or
11a-c (1.38 g, 10.0 mmol based on Si) and Et3N (0.697 mL,
5.00 mmol) or BuNH2 (0.494 mL, 5.00 mmol) in 50 mL
of acetone was refluxed for 48 hours. After the reaction
was complete, the solid was filtrated and washed with
acetone to give a mixture of (PhSiO3/2)8·acetone 2a and
(PhSiO3/2)12·acetone·H2O 3a as a white powder. The ratio of
2a to 3a in the mixture was determined by 1H NMR. The fil-
trate was evaporated and residue was separated by silica gel
short column chromatography with hexane: toluene (1:1) to
4.13
Condensation of PhSi(OH)3 and
|
[PhSi(O)OH]4 11a using DCC
A mixture of PhSi(OH)3 (1.56 g, 10.0 mmol based on Si) or
[PhSi(O)OH]4 11a (1.38 g, 10.0 mmol based on Si) and DCC
(4.64 g, 22.5 mmol or 1.55 g, 7.50 mmol) in 50 mL THF was
refluxed for 48 hours. After the reaction was complete, the
solvent was removed to yield a white solid. The solid was
washed with acetone to give a mixture of (PhSiO3/2)8·THF
2a and (PhSiO3/2)12·2THF 3a as a white powder. The ratio
of 2a to 3a in the mixture was determined by 1H NMR. The
mixture was separated by silica gel column chromatography
with toluene to afford (PhSiO3/2)12·toluene as a white solid.
afford (PhSiO3/2)10 4a as a white solid.
4.15
X-ray structure determination of
|
[Ph7Si7O9](OH)3 10a
Suitable crystals were obtained by recrystallization from chlo-
roform and hexane. 10a: C42H38O12Si7, M=931.35, triclinic
with a=14.4558 (13), b=14.8485 (13), c=23.0110 (30) Å,
α=84.317 (9), β=83.095 (8), γ=68.270 (6)°, V=4547.0
(8) Å3 space group P−1, Z=4, Dcalc=1.360 g cm−3, 20 335

KAWAKAMI et Al.
11 of 12
|
2
reflections, R=0.0651, Rw=0.1661 for data with |Fo |>2σ
Me3SiCl and ClCH2Me2SiCl and the Colcoat Co. Ltd for pro-
viding Si(OEt)4.
2
|Fo | (R=0.0929, Rw=0.2019 for all data), GOF=1.077. All
reflections [3.03≤θ≤27.52°] were measured on a RIGAKU
MERCURY diffractometer using CCD camera. The reflec-
tions collected/independent was 48 778/20 335, in which
REFERENCES
2
2
14 054 reflections [|Fo |>2σ |Fo |] were used for calcula-
tion of R. The structure was solved by the direct method
(SHELXS-97[16] and SIR 2004[17]) using WinGX v1.70.01
as interface.[18] The non-hydrogen atoms were refined
anisotropically by the full-matrix least-square method
(SHELXL-97).[16] Hydrogen atoms were placed at calculated
positions and kept fixed. In the subsequent refinement, the
[1] For recent reviews on polyhedral oligomeric silsesquioxanes
(POSS), see: a) M. G. Voronkov, V. I. Lavrent’yev, Top. Curr.
Chem. 1982, 102, 199; b) R. H. Baney, M. Itoh, A. Sakakibara,
T. Suzuki, Chem. Rev. 1995, 95, 1409; c) P. G. Harrison,
J. Organomet. Chem. 1997, 542, 141; d) D. B. Cordes, P. D.
Lickiss, F. Rataboul, Chem. Rev. 2010, 110, 2081; e) C. Marcolli,
G. Calzaferri, Appl. Organomet. Chem. 1999, 13, 213.
[2] For the silica surface and metallasiloxanes, see: a) F. J. Feher, T.
A. Budzichowski, Polyhedron 1995, 14, 3239; b) F. J. Feher, D.
A. Newman, J. F. Walzer, J. Am. Chem. Soc. 1989, 111, 1741; c)
R. Murugavel, A. Voigt, M. G. Walawalkar, H. W. Roesky, Chem.
Rev. 1996, 96, 2205.
function Σω (F2 −F2 )2 was minimized, where |Fo| and |Fc|
are the observed andccalculated structure factor amplitudes,
o
respectively. The agreement indices are defined as R1=Σ
(||Fo|−|Fc||)/Σ|Fo| and wR2=[Σω(F2 −F2 )2/Σ(ωF4 )]1/2
.
o
c
o
[3] For liquid crystals, dendrimer and porous solid, see: a) J. W.
Goodby, G. H. Mehl, I. M. Saez, R. P. Tuffin, G. Mackenzie,
R. Auzély-Velty, T. Benvegnu, D. Plusquellec, Chem. Commun.
1998, 2057; b) G. H. Mehl, J. W. Goodby, Chem. Commun.
1999, 13; c) F. J. Feher, K. D. Wyndham, Chem. Commun. 1998,
323; d) F. J. Feher, K. D. Wyndham, D. Soulivong, F. Nguyen,
J. Chem. Soc. Dalton Trans. 1999, 1491; e) P.-A. Jaffrès, R. E.
Morris, J. Chem. Soc. Dalton Trans. 1998, 2767; f) X. Zhang,
K. J. Haxton, L. Ropartz, D. J. Cole-Hamilton, R. E. Morris, J.
Chem. Soc. Dalton Trans. 2001, 3261; g) K. Naka, M. Fujita, K.
Tanaka, Y. Chujo, Langmuir 2007, 23, 9057; h) K. Tanaka, K.
Inafuku, K. Naka, Y. Chujo, Org. Biomol. Chem. 2008, 6, 3899;
i) Y. Gao, A. Eguchi, K. Kakehi, Y. C. Lee, Org. Lett. 2004, 6,
3457; j) C. Zhang, F. Babonneau, C. Bonhomme, R. M. Laine,
C. L. Soles, H. A. Hristov, A. F. Yee, J. Am. Chem. Soc. 1998,
120, 8380; k) T. Gunji, T. Shioda, K. Tsuchihira, H. Seki, T.
Kajiwara, Y. Abe, . Appl. Organometal. Chem. 2010, 24, 545;
l) P. G. Harrison, R. Kannengiesser, Chem. Commun. 1996, 415
and [1c]; m) R. Y. Kannan, H. J. Salacinski, P. E. Butler, A. M.
Seifalian, Acc. Chem. Res. 2005, 38, 879.
4.16
X-ray structure determination of
|
(PhSiO3/2)10 4a
Suitable crystals were obtained by recrystallization from
CH2Cl2. PhT10: C60H50O15Si10, M=1291.90, triclinic with
a=14.509 (3), b=14.619 (3), c=17.642 (4) Å, α=72.901
(14), β=78.655 (14), γ=62.559 (9)°, V=3165.9 (11) Å3
space group P−1, Z=2, Dcalc=1.355 g cm−3, 14 374 reflec-
tions, R=0.0455, Rw=0.1356 for data with |Fo |>2σ |Fo |
(R=0.0540, Rw=0.1475 for all data), GOF=1.084. All
reflections [3.17≤θ≤27.50°] were measured on a RIGAKU
MERCURY diffractometer using CCD camera. The reflec-
tions collected/independent was 38 200/14 374, in which
2
2
2
2
11 890 reflections [|Fo |>2σ|Fo |] were used for calcula-
tion of R. The structure was solved by the direct method
(SHELXS-97[16] and SIR 2004[17]) using WinGX v1.70.01
as interface.[18] The non-hydrogen atoms were refined
anisotropically by the full-matrix least-square method
(SHELXL-97).[16] Hydrogen atoms were placed at calculated
positions and kept fixed. In the subsequent refinement, the
[4] For the hydrolytic condensation of trialkoxysilanes, see: a) D. W.
Scott, J. Am. Chem. Soc. 1946, 68, 356; b) A. J. Barry, W. H.
Daudt, J. J. Domicone, J. W. Gilkey, J. Am. Chem. Soc. 1955,
77, 4248; c) J. F. Brown Jr., L. H. Vogt, P. I. Prescott, J. Am.
Chem. Soc. 1964, 86, 1120; d) A. R. Bassindale, Z. Liu, I. A.
MacKinnon, P. G. Taylor, Y. Yang, M. E. Light, P. N. Horton, M.
B. Hursthouse, Dalton Trans. 2003, 2945.
function Σω (F2 −F2 )2 was minimized, where |Fo| and |Fc|
are the observed andccalculated structure factor amplitudes,
o
respectively. The agreement indices are defined as R1=Σ
[5] For the preparation and silylation of cubic octasillicate (5): a) D.
Hoebbel, G. Garzό, G. Engelhardt, R. Ebert, E. Lippmaa, M. Alla,
Z. Anorg. Allg. Chem. 1980, 465, 15; b) D. Hoebbel, I. Pitsch,
T. Reiher, W. Hiller, H. Jancke, D. Müller, Z. Anorg. Allg. Chem.
1989, 576, 160; c) I. Hasegawa, K. Kuroda, C. Kato, Bull. Chem.
Soc. Jpn. 1986, 59, 2279; d) I. Hasegawa, S. Sakka, Y. Sugahara,
K. Kuroda, C. Kato, J. Chem. Soc. Chem. Commun. 1989, 208; e)
I. Hasegawa, S. Motojima, J. Organomet. Chem. 1992, 441, 373;
f) I. Hasegawa, M. Ishida, S. Motojima, Synth. React. Inorg. Met.-
Org. Chem. 1994, 24, 1099; g) I. Hasegawa, Trends Organomet.
Chem. 1994, 1, 131; h) I. Hasegawa, K. Ino, H. Ohnishi, Appl.
Organomet. Chem. 2003, 17, 287; i) P. A. Agaskar, Inorg. Chem.
1990, 29, 1603; j) M. Morán, C. M. Casado, I. Cuadrado, J.
Losada, Organometallics 1993, 12, 4327; k) S. E. Yuchs, K. A.
Carrado, Inorg. Chem. 1996, 35, 261; l) A. Provatas, M. Luft, J.
(||Fo|−|Fc||)/Σ|Fo| and wR2=[Σω(F2 −F2 )2/Σ(ωF4 )]1/2
.
Crystallographic data reportedoin this manuscript have
been deposited with Cambridge Crystallographic Data
Centre as supplementary publication no. CCDC-1539759 for
10a and 1539760 for 4a. Copies of the data can be obtained
free of charge via CCDC Website.
c
o
ACKNOWLEDGMENTS
This work was supported by a Grant-in Aid for a High-Tech
Research Center Project from the Ministry of Education,
Culture, Sports, Science and Technology, Japan. The authors
are grateful to the Shin-Etsu Chemical Co. Ltd. for gift of

12 of 12
KAWAKAMI et Al.
|
C. Mu, A. H. White, J. G. Matisons, B. W. Skelton, J. Organomet.
Chem. 1998, 565, 159; m) H. Liu, S. Kondo, N. Takeda, M. Unno,
J. Am. Chem. Soc. 2008, 130, 10074 and [1c].
[11] S. A. Gromilov, T. V. Basova, D. Y. Emel’yanov, A. V. Kuzmin,
S. A. Prokhorova, J. Struct. Chem. 2004, 45, 471.
[12] a) H. Uchida, Y. Kabe, K. Yoshino, A. Kawamata, T. Tsumuraya,
S. Masamune, J. Am. Chem. Soc. 1990, 112, 7077; b) K. Yoshino,
A. Kawamata, H. Uchida, Y. Kabe, Chem. Lett. 1990, 19, 2133.
[13] For POSS synthesis from condensation of silanolate (7) and poly-
silanol (11a): a) M. Unno, S. B. Alias, H. Saito, H. Matsumoto,
Organometallics 1996, 15, 2413; b) M. Unno, A. Suto, K.
Takada, H. Matsumoto, Bull. Chem. Soc. Jpn. 2000, 73, 215; c) S.
Tateyama, Y. Kakihana, Y. Kawakami, J. Organomet. Chem. 2010,
695, 898; d) M. Unno, H. Endo, N. Takeda, Heteroatom Chem.
2014, 25, 525; e) N. Oguri, Y. Egawa, N. Takeda, M. Unno, Angew.
Chem. Int. Ed. 2016, 55, 9336; f) J. C. Furgal, T. Goodson III, R.
M. Laine, Dalton Trans. 2016, 45, 1025.
[6] For the preparation and silylation of silanolate (6): H. Oikawa, K.
Watanabe, N. Ootake, K. Yoshida, K. Iwatani, International Pat.
Appl. PCT/JP02/04776. WO02/094839 (17 May, 2002).
[7] Preparation and silylation of incompletely condensed silsesquiox-
ane: a) F. J. Feher, J. Am. Chem. Soc. 1986, 108, 3850; b) See
Reference Feher et al. [2b]; c) J. D. Lichtenhan, Y. A. Otonari,
M. J. Carr, Macromolecules 1995, 28, 8435; d) R. Duchateau, H.
C. L. Abbenhuis, R. A. van Santen, S. K.-H. Thiele, M. F. H. van
Tol, Organometallics 1998, 17, 5222; e) H. Liu, S. Kondo, N.
Takeda, M. Unno, Eur. J. Inorg. Chem. 2009, 1317; f) S. Spirk,
M. Nieger, F. Belaj, R. Pietschnig, Dalton Trans. 2009, 163; g)
T. Maegawa, Y. Irie, H. Imoto, H. Fueno, K. Tanaka, K. Naka,
Polym. Chem. 2015, 6, 7500.
[14] S. D. Korkin, M. I. Buzin, E. V. Matukhina, L. N. Zherlitsyna,
N. Auner, O. I. Shchegolikhina, J. Organomet. Chem. 2003, 686,
313.
[15] a) M. A. Hossain, M. B. Hursthouse, K. M. A. Malik, Acta
Crystallogr. Sect. 1979, B35, 2258; b) W. Clegg, G. M. Sheldrick,
N. Vater, Acta Crystallogr. Sect. 1980, B36, 3162; c) M. F. Roll,
J. W. Kampf, Y. Kim, E. Yi, R. M. Laine, J. Am. Chem. Soc. 2010,
132, 10171.
[16] G. M. Sheldrick, Program for the Solution of Crystal Structures,
University of Göttingen, Germany.
[8] Preparation and characterization of silanolates (7, 8and 9). Review:
a) Y. T. Struchkov, S. V. Lindeman, J. Organomet. Chem. 1995,
488, 9; b) O. I. Shchegolikhina, V. A. Igonin, Y. A. Molodtsova, Y.
A. Pozdniakova, A. A. Zhdanov, T. V. Strelkova, S. V. Lideman, J.
Organomet. Chem. 1998, 562, 141; c) O. I. Shchegolikhina, Y. A.
Pozdniakova, M. Y. Antipin, D. Katsoulis, N. Auner, B. Herrschaft,
Organometallics 2000, 19, 1077; d) O. I. Shchegolikhina, Y. A.
Pozdnyakova, Y. A. Molodtsova, S. D. Korkin, S. S. Bukalov,
L. A. Leites, K. A. Lyssenko, A. S. Peregudov, N. Auner, D. E.
Katsoulis, Inorg. Chem. 2002, 41, 6892; e) Y. A. Molodtsova,
Y. A. Pozdnyakova, I. V. Blagodatskikh, A. S. Peregudov, O. I.
Shchegolikhina, Russ. Chem. Bull. Int. Ed. 2003, 52, 2722 and
[2c]; f) R. Ito, Y. Kakihana, Y. Kawakami, Chem. Lett. 2009, 38,
364; g) Y. A. Pozdnyakova, A. A. Korlyukov, E. G. Kononova, K.
A. Lyssenko, A. S. Peregudov, O. I. Shchegolikhina, Inorg. Chem.
2010, 49, 572.
[17] M. C. Burla, R. Caliandro, M. Camalli, B. Carrozzini, G. L.
Cascarano, L. De Caro, C. Giacovazzo, G. Polidori, R. Spagna, J.
Appl. Cryst. 2005, 38, 381.
[18] L. J. Farrugia, J. Appl. Cryst. 1999, 32, 837.
How to cite this article: Kawakami Y, Seino H,
Ohtaki K, Kabe Y. Synthetic application of silicates/
silanolates and their hydrolyzed polysilanol siloxanes
for polyhedral oligomeric silsesquioxanes (POSSs).
Heteroatom Chem. 2017;28:e21373. https://doi.
org/10.1002/hc.21373
[9] Y. Kawakami, K. Yamaguchi, T. Yokozawa, T. Serizawa, M.
Hasegawa, Y. Kabe, Chem. Lett. 2007, 36, 792.
[10] Different preparation of [Si8O20](SiMe3)7H (1b) from [Si8O19]
(SiMe3)7H: D. M. Millar, NTIS. Report (1987), (DOE/
ER/01198-T18; Order No. DE88014627), 169 pp. From: Energy
Res. Abstr. 1988, 13, Abstr. No. 49188.