Lamellar bridged silsesquioxanes: Self-assembly through a combination of hydrogen bonding and hydrophobic interactions

Article abstract of DOI:10.1002/chem.200401012

The synthesis of four bis-(trialkoxysilylated) organic molecules capable of self-assembly-(EtO)₃Si(CH₂)₃NHCONH-(CH ₂)_n-NHCONH(CH₂)₃Si(OEt)₃ (n = 9-12)-associating urea functional groups and alkylidene chains of variable length is described. These compounds behave as organogelators, forming supramolecular assemblies thanks to the intermolecular hydrogen bonding of urea groups. Whereas fluoride ion-catalysed hydrolysis in ethanol in the presence of a stoichiometric amount of water produced amorphous hybrids, acid-catalysed hydrolysis in an excess of water gave rise to the formation of crystalline lamellar hybrid materials through a self-organisation process. The structural features of these nanostructured organic/inorganic hybrids were analysed by several techniques: attenuated Fourier transformed infrared (ATR-FTIR), solid-state NMR spectroscopy (¹³C and ²⁹Si), scanning and transmission electron microscopy (SEM and TEM) and powder X-ray diffraction (PXRD). The reaction conditions, the hydrophobic properties of the long alkylidene chains and the hydrogen-bonding properties of the urea groups are determining factors in the formation of these self-assembled nanostructured hybrid silicas.

Full text of DOI:10.1002/chem.200401012

FULL PAPER
Lamellar Bridged Silsesquioxanes: Self-Assembly through a Combination of
Hydrogen Bonding and Hydrophobic Interactions
Joꢀl J. E. Moreau,*[a] Luc Vellutini,[a] Michel Wong Chi Man,[a] Catherine Bied,[a]
Philippe Dieudonnꢁ,[b] Jean-Louis Bantignies,[b] and Jean-Louis Sauvajol[b]
Abstract: The synthesis of four bis-
(trialkoxysilylated) organic molecules
presence of a stoichiometric amount of
water produced amorphous hybrids,
acid-catalysed hydrolysis in an excess
of water gave rise to the formation of
crystalline lamellar hybrid materials
through a self-organisation process.
The structural features of these nano-
structured organic/inorganic hybrids
were analysed by several techniques:
attenuated Fourier transformed infra-
red (ATR-FTIR), solid-state NMR
spectroscopy (13C and 29Si), scanning
and transmission electron microscopy
(SEM and TEM) and powder X-ray
diffraction (PXRD). The reaction con-
ditions, the hydrophobic properties of
the long alkylidene chains and the hy-
drogen-bonding properties of the urea
groups are determining factors in the
formation of these self-assembled
nanostructured hybrid silicas.
capable
(EtO)3Si(CH2)3NHCONH (CH2)n
NHCONH(CH2)3Si(OEt)3 (n
of
self-assembly—
À
À
=
9–
12)—associating urea functional groups
and alkylidene chains of variable
length is described. These compounds
behave as organogelators, forming
supramolecular assemblies thanks to
the intermolecular hydrogen bonding
of urea groups. Whereas fluoride ion-
catalysed hydrolysis in ethanol in the
Keywords: bridged silsesquioxanes ·
gels · nanomaterials · self-assembly ·
self-organised hybrids
Introduction
cally active solids,[7] as extracting solids for lanthanides and
actinides,[8] as materials for optics and opto-electronics.[9]
These functional hybrid silicates, prepared by hydrolysis of
alkoxyorganosilanes in solution, are amorphous solids de-
spite some intermolecular interactions, and organisation be-
tween the organic fragments has been suspected on the
basis of chemical reactivities.[7,10]
Nanostructuring and control over morphology in hybrid
solids are of great interest for the design of polyfunctional
materials.[11] Recently, the surfactant-mediated pathway,[12]
originally used to produce periodic mesoporous silicas, has
been successfully extended to bridged silsesquioxanes.[13]
The use of an external surfactant resulted in shape-control-
led hybrids[14] and in hybrids with highly ordered hexagonal
mesoporous structures.[13,14] In silsesquioxane hybrids, the
bridging organic unit itself can be used to direct the struc-
ture of the solid network without addition of an external
structure-directing agent. Weak interactions between precur-
sor molecules during the hydrolysis–condensation of trial-
koxysilanes has been shown to influence the kinetic parame-
ters of the gelation[15] and to modify the texture and mor-
phology of silsesquioxane.[16] Anisotropic organisation due
to interactions between rigid aromatic units was interesting-
ly demonstrated by the generation of birefringent silses-
quioxane materials.[17] Moreover, mesoporous phenylene-
The use of sol–gel processing has proved to be a powerful
method for the production of solid hybrid materials.[1,2]
Over the last decade, polysilsesquioxanes arising from the
sol–gel hydrolysis of polysilylated organic molecules[3–8] have
allowed the synthesis of new organic/inorganic hybrids by
design. The properties of the resulting hybrid solids can be
tuned by the introduction of appropriate organic functionali-
ty into the silicate network through covalent linkage. Bridg-
ed silsesquioxanes have proven efficient, for example, as
enantioselective heterogeneous catalysts,[6] as electrochemi-
[a] Prof. Dr. J. J. E. Moreau, Dr. L. Vellutini, Dr. M. Wong Chi Man,
Dr. C. Bied
Hꢀtꢀrochimie Molꢀculaire et Macromolꢀculaire (UMR-CNRS 5076)
Ecole Nationale Supꢀrieure de Chimie de Montpellier
8, rue de l’ꢀcole normale
34296 Montpellier cꢀdex 5 (France)
Fax : (+33)467-147-212
E-mail: jmoreau@cit.enscm.fr
[b] Dr. P. Dieudonnꢀ, Dr. J.-L. Bantignies, Dr. J.-L. Sauvajol
Groupe de Dynamique des Phases Condensꢀes (UMR-CNRS 5581)
Universitꢀ de Montpellier II
Place Eugꢁne Bataillon
34095 Montpellier cꢀdex 5 (France)
Chem. Eur. J. 2005, 11, 1527 – 1537
DOI: 10.1002/chem.200401012
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1527

bridged silsesquioxanes with ordered hexagonal pore struc-
ture and crystalline pore walls have been obtained recent-
ly.[18]
We recently developed a new and efficient approach for a
controlled synthesis of organically bridged silicas through
the design and hydrolysis of trialkoxyorganosilanes that ex-
hibit hydrogen-bonding interactions,[9c,19,20] providing a route
to the generation of self-organised hybrid silicas. As demon-
strated in the case of silicas,[21] transcription of the chiral
properties of the molecular precursor to the hybrid solid
was achieved. Under acidic conditions in water, helical hy-
brids with controlled handedness formed upon hydrolysis of
the R,R or S,S enantiomers of diurea derivatives of trans-
(1,2)-diaminocyclohexane.[19a] Long-range ordered hybrids
were achieved when hydrogen-bonding interactions were
combined with aromatic p–p or
Scheme 1. Synthesis of self-organised lamellar alkylene-bridged silses-
quioxanes.
hydrophobic interaction.[19b,20]
The organic bridging substruc-
ture plays an important role in
controlling the arrangement of
the crystalline lamellar materi-
al. In the work in this paper we
Scheme 2. Synthesis of the precursors Px (x = 9–12).
have studied the contribution of
the main organic alkylidene bridging substructure in combi-
nation with the urea groups in the self-organisation of these
hybrid solids. We report self-organised lamellar bridged sil-
sesquioxanes obtained by the acid-catalysed (HCl) hydroly-
sis of bis(trialkoxysilylated) organic molecules combining
urea functional groups and alkylidene chains of variable
and washing with dry cold pentane. The pure precursors P9–
P12 were isolated as microcrystalline solids in 80–93%
yields, and were soluble in CH2Cl2, THF or EtOH. As has
been observed for related bis(urea)-based molecules[22–24]
P9–P12 behave as gelators in CHCl3 or toluene at low con-
centrations (ca. 10 gLÀ1). Evidence for the intermolecular
association of the urea groups was obtained from the FTIR
spectra of the precursors P9–P12 in solution and in the solid
state. Diluted CHCl3 solutions of the precursors showed the
À
À
length:
(EtO)3Si(CH2)3NHCONH (CH2)n
NHCONH(CH2)3Si(OEt)3, with n = 9–12. Whereas sol–gel
hydrolysis–condensation produced amorphous materials
when catalysed by fluoride ion in ethanol, acid-catalysed hy-
drolysis allowed the generation of long-range ordered self-
organised lamellar bridged silsesquioxanes with variable in-
terlamellar distances depending on the lengths of the organ-
ic spacers.
vibrations characteristic of free urea groups:[25] nNÀ = 3445,
H
nC (amide I) = 1654 and dNÀ (amide II) = 1538 cmÀ1. At
=
O
H
higher concentrations, as organogels the vibration bands
shifted towards lower frequencies: À125 cmÀ1 for nNÀ and
H
À35 cmÀ1 for nC O. At the same time, the dNÀ band shifted
=
H
by +35 cmÀ1 towards higher frequencies. This behaviour is
characteristic of strongly associated urea groups between
P9–P12 molecules.[25] In the solid state, the observed vibra-
tions for the four microcrystalline precursors appeared at
Results and Discussion
We have studied how the combination of the self-assembly
properties of urea groups[22–24] with the hydrophobic interac-
tions provided by long hydrocarbon chains can direct the hy-
drolysis–condensation of linear bis-trialkoxysilylalkanes in
order to generate self-organised hybrids with tuneable la-
mellar spacings (Scheme 1).
1623 cmÀ1 (nC O) and 1577 cmÀ1 (dNÀH). The Dn value
=
(nC OÀdNÀH) of 46 cmÀ1 is indicative of strong association of
=
the urea groups by hydrogen bonds. No significant variation
in the hydrogen bond strength as a function of chain length
(nine to twelve carbon atoms) was observed, since identical
Dn values were measured for P9–P12. Some differences ap-
peared in the nNÀ region, with the solid-state spectra of P9–
H
Synthesis of silyl precursors containing long hydrocarbon
chains: The four molecular precursors P9 to P12, containing
nine- to twelve-carbon alkylene units, were synthesized by
treatment of a,w-diamino or a,w-diisocyanato alkanes with
3-(isocyanatopropyl)triethoxysilane or 3-(aminopropyl)tri-
ethoxysilane, respectively (Scheme 2).
The reactions between the amino groups and the isocya-
nates to form ureas were quantitative, and the reaction
products were easily purified after elimination of the solvent
P12 exhibiting bands at 3347 and 3319 cmÀ1, in comparison
with the solution spectra (nNÀ = 3445 cmÀ1) and the gel
H
spectra (nNÀ = 3320 cmÀ1). These are indicative of two
ÀH
types of N H bonds, the stronger being centred at low fre-
quency (3319 cmÀ1) at a value close to the value observed in
the organogel. Similar behaviour was observed for all pre-
cursor molecules whatever the length of the alkylene chain.
Clearly the intermolecular associations by hydrogen bonds
are weakly sensitive to the length of the spacer.
1528
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2005, 11, 1527 – 1537

Lamellar Bridged Silsesquioxanes
FULL PAPER
Hydrolysis–condensation of P9–P12: The hydrolysis–con-
densation of the four precursors, to give hybrid networks,
was performed under two different sets of reaction condi-
tions: with nucleophilic catalysis, in which case the conden-
sation is the faster reaction, and with acid catalysis, in which
hydrolysis is the faster step.
This was first achieved under normal sol–gel conditions
by dissolution of the molecular precursor in ethanol and
subsequent addition of a stoichiometric amount of water
(6 mol equiv) and a catalytic quantity of NH4F. The viscosity
of the reaction mixture increased up to the formation of a
transparent gel phase after 24 h. The system was cured for
48 h, and the obtained solid materials A9–A12 were dried
overnight at 1108C (Scheme 3). We then studied different
reaction conditions without EtOH solvent, with use of a
large excess of water to favour hydrophobic intermolecular
interaction between precursor molecules. Hydrolysis–con-
densation was achieved in the presence of HCl as catalyst
(pH 2; to ensure fast hydrolysis of the precursors). Products
obtained in this manner were not soluble but partly dis-
solved upon hydrolysis. Heating of the heterogeneous mix-
ture at 808C for 48 h resulted in condensation and afforded
the solid materials L9–L12 (Scheme 3) after drying as in the
previous case.
Figure 1. 13C CP-MAS solid-state NMR spectra of hybrid silicas A12 and
L12.
The compositions of the hybrid materials A9–A12 and
L9–L12 were characterised by elemental analysis and by 13C
and 29Si solid-state NMR spectroscopy. The analysis re-
vealed N/Si ratios of 2:1 for all solids, consistent with the
structures represented in Scheme 3, indicating that the or-
ganic substructure was retained during the hydrolysis–con-
densation whatever the reaction conditions; this was also
confirmed upon examination of the solid-state 13C NMR
spectra of all materials. The spectra of A12 and L12 are
shown in Figure 1 as examples.
The signals at d=160, 43, 34, 31, 26 and 11 ppm corre-
spond to the carbonyl and sp3 carbon atoms of the alkyl
chain. The absence of signals at d=18 and 58 ppm (ethoxy
À
groups) is indicative of complete hydrolysis of the Si OEt
groups under the reaction conditions. Interestingly, the lines
in L12 appeared narrower than their counterparts in A12,
which reflects a more homogeneous arrangement and higher
mobility of the organic substructure in L12 than in A12.
Similar observations were made for the other materials, and
were confirmed upon examination of the 29Si NMR spectra
(Figure 2).
Broader signals were observed for A12, with resonances
at d=À58 [T2: CSi(OSi)2OH] and À67 ppm [T3: CSi(OSi)3]
corresponding to a degree of condensation of 90%. The
Figure 2. 29Si CP-MAS NMR solid-state spectra of hybrid silicas A12 and
L12.
Scheme 3. Synthesis of lamellar (L9–L12) or amorphous (A9–A12) bridged silsesquioxanes.
Chem. Eur. J. 2005, 11, 1527 – 1537
www.chemeurj.org
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1529

J. J. E. Moreau et al.
spectra of L12 revealed sharper signals at d=À49 [T1:
CSi(OSi)(OH)2], À58 [T2: CSi(OSi)2OH] and À67 ppm [T3:
CSi(OSi)3] with a degree of condensation of 65%. The much
higher degree of condensation, resulting in a more rigid
hybrid network in A12 than in L12, is consistent with the
previous NMR observations, and is a result of the different
reaction conditions. Fluoride ion catalysis gives fast conden-
sation in relation to the hydrolysis rate, and results in a
highly condensed and rigid hybrid network. Conversely,
rapid hydrolysis and slower condensation occur in the acid-
catalysed reaction and this results in a less condensed hybrid
network.[4,26]
Structural ordering in hybrids A9–A12 and L9–L12: X-ray
analysis of the various hybrids revealed interesting features.
The diffraction diagrams of materials A9–A12 showed
broad bands consistent with essentially amorphous struc-
tures, as usually observed for related silsesquioxanes.[3,4]
Conversely, the X-ray diffraction spectra of materials L9–
L12 showed intense Bragg peaks indicative of medium- to
long-range ordered lamellar structures (Figure 3).
A first intense peak (001) at a low q value (0.241, 0.240,
0.229 and 0.215 ꢃÀ1for hybrids L9 to L12, respectively) was
observed. Peaks of lower intensity at q values of 0.65–0.72
and 0.86–0.96 ꢃÀ1 could be associated with third (003) and
fourth (004) orders of the high intensity peaks (001) at low
q values. This corresponds to characteristic distances of 26.3
to 29.2 ꢃ for materials L9 to L12, respectively. Interestingly,
these distances are compatible with the lengths of the organ-
ic spacers in the precursors containing hydrocarbon chains
with nine to twelve carbon atoms. A schematic representa-
tion of the structure of the lamellar hybrids is shown in
Scheme 4.
Figure 3. a) X-ray diffraction diagrams of the ordered hybrid silicas L9–
L12; b) expansion of the region q=0.60–1.10 ꢃÀ1
.
This schematic representation is based on the recent de-
termination of the structures of related materials containing
(1,4)-bis(ureido)phenylene-bridged units.[20] It consists of
ribbons containing the organic substructures bonded by in-
termolecular hydrogen bonds of the urea groups. The dif-
fraction peaks at the lowest q values (Figure 3) could de-
scribe the distances between si-
peaks appeared, indicative of an increase in amorphous
character with decreasing chain length. Shorter organic
chains containing six to eight carbon atoms have been
shown to afford amorphous hybrids whatever the reaction
conditions.[27]
lylated ribbons. The other
peaks at higher q values (1.45–
1.70 ꢃÀ1) in the diffraction dia-
grams could be attributed to in-
termolecular distances along a
ribbon controlled by the urea
units (4.5 ꢃ) associated through
hydrogen bonds or to in-plane
ordering.[9c,20]
On going from L12 to L9
(Figure 3), the most intense
peak shifted towards higher
q values, consistently with a de-
crease in the organic chain
length from twelve to nine
carbon atoms. At the same
time, some broadening of the Scheme 4. Schematic representation of the structures of the ordered hybrid silicas L9–L12.
1530
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2005, 11, 1527 – 1537

Lamellar Bridged Silsesquioxanes
FULL PAPER
are an interesting probe for ex-
ploring hydrogen-bonding inter-
actions between organic sub-
structures in the hybrid network
and can also provide evidence
for preferential orientation and
organisation within the materi-
als.
The IR spectra of the amor-
phous materials A9 to A12,
measured at room temperature,
are quite similar. The spectrum
of A12 over two wavenumber
ranges (n˜
= 2800–3500 and
1500–1800 cmÀ1) is given as an
example in Figure 7.
Broad bands are observed at
3374 cmÀ1 (nNÀH), 1645 cmÀ1
(nC
)
and 1577 cmÀ1 (dNÀH).
=
O
These wavenumbers are indica-
tive of hydrogen-bonded urea
groups, but in agreement with
the amorphous character of
A12, corresponding to a non-
homogeneous distribution of
Figure 4. SEM images of amorphous hybrid silicas A9–A12 with granular morphology.
Electron microscopy studies on the various hybrids re-
vealed morphologies consistent with their amorphous or or-
dered structures. Scanning electron microscopy (SEM)
images of materials A9–A12 are presented in Figure 4.
These show dense, compact solids with granular morpholo-
gies.
hydrogen bonding, which is responsible for the broadening
of the bands in the IR spectrum. The lamellar hybrids L9–
L12 also gave similar spectra, though with narrower bands
than those observed for A9–A12, centred at 3348 and
3320 cmÀ1 (nNÀH), 1623 cmÀ1 (nC O) and 1585 cmÀ1 (dNÀ
)
H
=
(Figure 8).
Conversely, the hybrids L9–L12 presented homogeneous
lamellar morphologies consisting of thin plates 1–3 mm wide,
3–30 mm long and 0.05–0.5 mm thick (Figure 5). These plates
look like flexible films, which are still arranged in layers for
shorter chain lengths, particularly in L9.
Interestingly, the transmission electronic microscopy
(TEM) images confirmed the layered structures by showing
some well ordered features with lamellar spacings
(Figure 6). The interlayer spacings observed in the TEM
images are consistent with the lengths of the organic spacers
and with the distances calculated from the Bragg peaks at
low q values. Additionally, the half-widths at the half-
maxima of these peaks allowed correlation lengths of 270–
350 ꢃ to be determined, in the same order of magnitude as
the plate thickness observed from the TEM images.
The organisation and long-range order in L9–L12 ap-
peared to be dependent on the hydrophobic properties of
the alkylene spacers in the organic substructures. The forma-
tion of the lamellar hybrid phase was only observed upon
hydrolysis–condensation in water, whereas this produced
amorphous hybrids when the less hydrophobic ethanol was
used. The combination of hydrogen-bond and hydrophobic
interactions allowed ordered hybrids to be generated.
These vibrations appeared similar to those observed for
the precursors in the solid state; however, more strongly hy-
drogen-bonded urea groups appeared in the lamellar hybrid
solid. The value of Dn (= 38 cmÀ1) was lower than that in
the precursors (Dn = 46 cmÀ1). This difference arises from a
shift of the dNÀ vibration (1585 versus 1577 cmÀ1) towards
H
À
higher frequencies, indicating that N H deformation is a
more sensitive indicator of hydrogen-bonding interactions.
The vibration modes also showed temperature dependence,
which was studied over the 260 K to 10 K range. The lamel-
lar hybrid L10 showed Dn values from 34 cmÀ1 (260 K) to
22 cmÀ1 (10 K) towards lower frequencies, indicating stron-
ger hydrogen-bonding interactions at low temperatures. The
same trend, though weaker, was observed in the case of the
amorphous solid A10, with Dn values of 72 cmÀ1 (260 K)
and 52 cmÀ1 (10 K).
The above results clearly showed that the hydrogen-bond-
ing interactions were playing an important role in control-
ling the structures of the hybrids. Since hydrogen bonds are
directional interactions, it was of interest to explore their
possible anisotropic orientation within the solid. This was
studied by FTIR by the attenuated total reflection (ATR)
technique through examination of the polarisation depend-
ence of the vibration modes. The FTIR-ATR spectra of the
amorphous A12 and lamellar L12 hybrids are shown in
Figure 9. H-polarisation refers to transmission spectra ob-
Hydrogen-bonding interactions in amorphous and lamellar
hybrids: The characteristic IR vibrations of the urea groups
Chem. Eur. J. 2005, 11, 1527 – 1537
www.chemeurj.org
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1531

J. J. E. Moreau et al.
of Dn in H-polarisation in rela-
tion to that in V-polarisation is
related to a more significant
contribution of hydrogen-bond
strength for modes polarised in
the H-polarisation than in the
V-polarisation. The pressure ap-
plied on the sample induces ori-
entation of the layered hybrid
parallel to the ATR prism sur-
face. The above observations
are consistent with the model in
Scheme 4
with
hydrogen-
bonded urea groups in planes
perpendicular to the lamellae
and carbonyl groups oriented
parallel to the lamellar plan.
Discussion: The above results
show that the synthesis of the
hybrid solid, the result of the
formation of strong covalent si-
À À
loxane (Si O Si) bonds, is con-
trolled by weak intermolecular
interactions between the organ-
ic substructures. This shows that
self-organisation processes can
be easily used in hybrid silses-
quioxanes to produce nano-
structured materials. The com-
bination of hydrogen-bonding
interactions and hydrophobic
interactions appeared crucial in
directing the hybrid network
formation.
The reaction conditions also
have a crucial role. A large
excess of water in the hydroly-
sis–condensation step appeared
necessary. Organised lamellar
hybrids were obtained in water,
Figure 5. SEM images of ordered hybrid silicas L9–L12.
whereas the use of a stoichio-
metric amount of water in etha-
tained with the electric vector parallel to the diamond/
hybrid solid interface, V-polarisation to transmission spectra
with the electric vector at 458 to the interface. The amor-
phous hybrid A12 gave similar H- and V-polarisation spec-
tra. Conversely, strong polarisation dependence was ob-
nol afforded amorphous solids. This is probably related to
more favourable development of hydrophobic interactions
in water than in the less polar ethanol. The nature of the
catalyst also plays an important role. As already mentioned,
Table 1. Polarisation dependence of Dn (= nC ÀdNÀH) values for A10–
=
O
served in the case of L12, both for amide I (nC O) and for
=
A12 and L10–L12.
amide II (dNÀH). The modes at 1618 cmÀ1 (nC
) and
=
O
Amorphous or
lamellar hybrid
Dn [cmÀ1
H-polarisation
]
Dn [cmÀ1
]
V-polarisation
1583 cmÀ1 (dNÀH) in the H-polarisation shift to 1621 and
1579 cmÀ1, respectively, in the V-polarisation. Similar results
were obtained for materials A10, A11, L10 and L11. The Dn
values are given in Table 1.
A10
A11
A12
L10
L11
L12
62
62
66
34
33
35
62
62
66
39
40
42
The strong decrease in Dn in the lamellar hybrid is in per-
fect agreement with the presence of oriented hydrogen-
bonded urea groups in the lamellar hybrids. The lower value
1532
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2005, 11, 1527 – 1537

Lamellar Bridged Silsesquioxanes
FULL PAPER
Figure 6. TEM images of lamellar hybrid silicas L9–L12.
catalysis by nucleophilic fluoride ion, which allows fast con-
densation, results in an amorphous material. Conversely,
acid catalysis, which allows fast hydrolysis and slower con-
densation than under nucleophilic catalysis conditions, pro-
vides organised lamellar solids. Accordingly, the average
degree of condensation of the siloxane network appeared
higher for the amorphous material produced by fluoride
ion-catalysed hydrolysis–condensation than for the organ-
ised material arising from acid catalysis of the reaction (90
versus 65%). Clearly, rapid condensation to form a rigid
and a highly condensed siloxane network resulted in amor-
phous material. In contrast, the slower and more limited
condensation to form a more flexible siloxane network fav-
oured the arrangement of the
Figure 7. IR spectrum of amorphous hybrid silica A12.
structures, which may then condense into a layered network.
However further studies to clarify the exact mechanistic
pathway are necessary. Whereas the precursors dissolved in
ethanol, they did not completely dissolve in water upon hy-
organic fragments, which self-
assembled through a combina-
tion of hydrogen-bonding inter-
actions between urea groups
and hydrophobic interactions
between the alkylene chains.
The precursors, which hydrolyse
À
to Si OH-containing molecules,
behave as amphiphilic mole-
cules capable of self-assembly
(Scheme 5).
The production of dimeric or
oligomeric association of the
precursor molecules may en-
hance inter-aggregate condensa-
tion rates. We have previously
reported entropy-favoured con-
densation by use of metal tem-
plating effects for related mate-
rials.[15] The condensation can
produce ladder-type oligomeric Figure 8. IR spectra of lamellar hybrid silicas L9–L12.
Chem. Eur. J. 2005, 11, 1527 – 1537
www.chemeurj.org
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1533

J. J. E. Moreau et al.
Scheme 5. Schematic representation of the hydrolysis–condensation process affording organised hybrids.
ganised lamellar solid. The role of the hydrocarbon chain is
also important, since some amorphous contribution ap-
peared in the lamellar material upon reduction of the chain
length to nine carbon atoms.
Conclusion
Hybrid silsesquioxane materials are of great interest in of-
fering a possible synthesis of nanostructured materials by
design. In the context of molecular engineering, the self-con-
densation properties of the precursor molecules can be
tuned to form supramolecular assemblies. Here a combina-
tion of hydrogen-bonding and hydrophobic interactions al-
lowed the formation of lamellar materials, the stacking of
the organic substructures directing the condensation of the
inorganic silicate network. We are currently investigating
the structuring of materials by supramolecular engineering.
The synthesis of programmed precursor molecules with ap-
propriate tuning of their self-assembling properties should
allow the generation of materials with structuring at differ-
ent nano- to microscopic scales. Moreover, the introduction
of functional groups should give rise to materials of interest,
for example, for molecular recognition, advanced catalysis,
electronics, opto-electronics and magnetism.
Experimental Section
Figure 9. Polarisation dependence of the FTIR-ATR spectra of A12 and
L12.
General information and techniques: The syntheses of the molecular pre-
cursors were carried out under nitrogen atmosphere by use of a vacuum
line and Schlenk techniques. 3-Isocyanotopropyltriethoxysilane was pur-
chased from Aldrich and was distilled before use. The other reagents and
solvents were purchased from ABCR, Acros, Aldrich, Alfa-aesar, Fluka
and Lancaster and were used without any further purification. n-Pentane
was distilled from LiAlH4, dichloromethane from P2O5, and ethanol from
magnesium turnings. Melting points were determined on an electrother-
mal apparatus (IA9000 series) and are uncorrected. Elemental analyses
were carried out by the “Service Central d’Analyse du CNRS” in Vernai-
son, France.
1H, 13C and 29Si NMR spectra in solution were recorded on Bruker
AC 200 and AC 250 spectrometers at room temperature in deuterated
chloroform as solvent and with TMS as internal reference. 1H, 13C and
29Si solid-state NMR spectra were obtained on Bruker FT-AM 200 or FT-
AM 400 spectrometers by use of cross-polarization and magic-angle spin-
ning techniques (CP-MAS) with TMS as reference for the chemical
shifts.
À
drolysis of Si OEt groups. The reaction mixture is heteroge-
neous and the hybrid network formation may also arise
from some hydrolysis–condensation in the solid state. The
use of a soluble phenylene-bridged precursor has recently
allowed a better insight into the self-organisation mecha-
nism.[20] The above studies allowed self-organised hybrids to
be generated on the basis of the self-assembly properties of
the molecular precursors. Hydrogen-bonding interactions
between organic substructures in the hybrid network ap-
peared stronger than intermolecular hydrogen bonding in
the microcrystalline precursor. Strongly oriented hydrogen-
bonded urea groups were characterised in the case of the or-
1534
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2005, 11, 1527 – 1537

Lamellar Bridged Silsesquioxanes
FULL PAPER
BET surface areas were obtained with a Micromeritics Gemini 2375 ap-
paratus.
boxylic acid (1.95 g, 8 mmol) suspended in dry CH2Cl2 (20 mL). After the
mixture had been heated at reflux overnight, the solvent and unreacted
thionyl chloride were evaporated in vacuum and the residual liquid was
distilled. Yield: 2 g, 90%; b.p. 120–1228C (5ꢄ10À2 mm Hg); 1H NMR
(200 MHz, CDCl3): d = 1.27 (m, 14H; CH2), 1.7 (m, 4H; CH2CH2CO),
2.87 ppm (t, 4H; CH2CO); 13C NMR (200 MHz, CDCl3): d = 173.73
(CO), 47.07 (CH2CO), 29.31, 29.21, 28.99, 28.37, 25.03 (5ꢄCH2); IR
(KBr): n˜ = 1794 cmÀ1 (nCO).
TEM images were performed with a JEOL 200 CX microscope and a
JEOL JEM 2010 microscope. SEM images were obtained with
JEOL 6300F apparatus.
a
Powder X-ray diffraction (PXRD) measurements and data treatment
were performed at the “Groupe de Dynamique des Phases Condensꢀes”
in Montpellier. The X-ray diffraction experiments were carried out on
solid powders in glass capillaries (1 mm diameter) in a transmission con-
figuration. A copper rotating anode X-ray source (4 kW) with a multilay-
1,11-Diisocyanatoundecane: Undecane-1,11-dioyl dichloride (3.73 g,
13.3 mmol) in acetone (5 mL) was added slowly to a cooled solution
(08C) of sodium azide (3.58 g, 55.16 mmol) in acetone (30 mL). After
stirring for 4 h (08C to RT), the reaction mixture was transferred under
nitrogen into a three-necked flask containing toluene (440 mL) and the
mixture was heated at 658C overnight. The solvent was removed and the
liquid residue was filtered on celite and washed with pentane. The sol-
vent was removed under vacuum and the liquid residue was purified by
distillation. Yield: 2.3 g, 73%; b.p.: 1148C (5ꢄ10À2 mm Hg); 1H NMR
er focusing “Osmic” monochromator giving high flux (108 photonssÀ1
and punctual colimation was employed. lKa 1.542 ꢃ. An “Image
)
=
plate” 2D detector was used. The diffraction curves were obtained,
giving diffracted intensity as a function of the wave vector q. The diffract-
ed intensity was corrected by exposition time, transmission and intensity
background coming from diffusion by an empty capillary.
Routine IR data were obtained on a Perkin–Elmer 1000 FT-IR spectro-
photometer.
(200 MHz, CDCl3):
d = 1.31 (m, 14H; CH2), 1.53–1.63 (m, 4H;
CH2CH2CO), 3.28 ppm (t, 4H; CH2NCO); 13C NMR (200 MHz, CDCl3):
Attenuated total reflection IR (FTIR-ATR) spectra with polarised light
were measured on a Perkin–Elmer spectrum one with a KRS5 polariser.
d
= 93.7 (NCO), 42.98 (CH2NCO), 31.28, 29.38, 28.9, 26.5 ppm (4ꢄ
CH2); IR (KBr): n˜ = 2274 cmÀ1 (nNCO); elemental analysis calcd (%) for
General method for the preparation of the precursors: In a typical syn-
thesis, 1,9-diaminononane (1.12 g, 7 mmol) was dissolved in dried di-
chloromethane (40 mL) under nitrogen in a Schlenk tube. 3-Isocyanato-
propyltriethoxysilane (3.53 g, 14.3 mmol) was slowly added by syringe at
room temperature. The mixture was stirred for 12 h and the solvent was
removed in vacuum to give an off-white solid. This was washed three
times with dried n-pentane and finally dried in vacuo.
C13H22O2N2: C 65.5, H 9.31, N 11.76; found: C 65.63, H 9.39, N 11.85.
1,11-Bis[(triethoxysilyl)propylureido]undecane (P11): (3-Aminopropyl)-
triethoxysilane (4.33 g, 19.58 mmol) was slowly added at 08C to a stirred
solution of 1,11-diisocyanatoundecane (2.32 g, 9.74 mmoles) in dry
CH2Cl2 (20 mL). After the mixture had been stirred overnight, the sol-
vent was removed in vacuo to yield an off-white solid. Unreacted (3-ami-
nopropyl)triethoxysilane was removed by washing with dry pentane.
After drying under vacuum (2ꢄ10À2 mm Hg), P11 was obtained as a
white solid. Yield: 5.3 g, 80%; m.p.: 112–1148C; 1H NMR (200 MHz,
CDCl3): d = 0.57–0.65 (m, 4H; CH2Si), 1.2 (t, 18H; CH3), 1.44, 1.58 (m,
1,9-Bis[(triethoxysilyl)propylureido]nonane (P9): Yield: 4.57 g, 90%;
m.p. 115–1178C; 1H NMR (200 MHz, CDCl3): d = 0.52–0.6 (m, 4H;
CH2Si), 1.15 (t, 18H; CH3), 1.36–1.56 (m, 18H; 9ꢄCH2), 3.05–3.08 (m,
8H; CH2 NH), 3.75 (q, 12H; OCH2), 5.43–5.49 ppm (m, 4H; NH); 13C
À
À
22H; 11ꢄCH2), 3.07, 3.17 (m, 8H; CH2 NH), 3.78 (q, 12H; OCH2), 4.87
(2H; NH), 4.98 ppm (2H; NH); 13C NMR (200 MHz, CDCl3): d
=
NMR (200 MHz, CDCl3): d = 159.1 (CO), 58.3 (OCH2), 42.8, 40.0 (2C;
CN), 30.2, 29.2, 28.9, 26.6, 23.7 (5C; CH2), 11.2 (CH3), 7.6 ppm (CH2Si);
29Si NMR (250 MHz, CDCl3): d = À45 ppm; IR (KBr, pellet): n˜ = 957,
À
158.84 (CO), 58.37 (OCH2), 42.85, 40.33 (2ꢄC N), 30.27, 29.29, 29.20,
29.14, 26.76, 23.69 (6ꢄCH2), 18.26 (CH3), 7.62 ppm (Si CH2); 29Si NMR
À
1076, 1104 (nSiÀO), 1576 (dNÀH), 1622 (nC O), 2855, 2934, 2976 (nCÀH),
=
(250 MHz, CDCl3): d = À45.1 ppm; IR (KBr, pellet): n˜ = 958, 1079,
1106 (nSiO), 1577 (dNH), 1623 (nCO), 2851, 2931, 2976 (nCH), 3346 cmÀ1
(nNH); elemental analysis calcd (%) for C31H68O8N4Si2: C 54.67, H 10.07,
N 8.23; found: C 54.68, H 10.03, N 8.40.
3342 cmÀ1 (nNÀH); elemental analysis calcd (%) for C29H64O8N4Si2: C
53.34, H 9.88, N 8.58; found: C 53.09, H 9.88, N 8.48.
1,10-Bis[(triethoxysilyl)propylureido]decane (P10): The preparation of
this compound was as described for P9, but starting from 1,10-diaminode-
cane (1.03 g, 6 mmol) and g-isocyanatopropyltriethoxysilane (3 g,
12.12 mmol). After drying under vacuum (2ꢄ10À2 mm Hg), P10 was ob-
tained as a white solid. Yield: 3.7 g, 93%; m.p. 114–1168C; 1H NMR
(200 MHz, CDCl3): d = 0.50–0.59 (m, 4H; CH2Si), 1.14 (t, 18H; CH3);
Acid-catalysed hydrolysis and polycondensation
General method for the preparation of the lamellar bridged silsesquiox-
anes L9–12: A mixture containing a molar ratio of Px/H2O/HCl 1:600:0.2
was vigorously stirred at 808C for 1 h and then allowed to stand for 48 h
at the same temperature. The solid, which formed quantitatively, was re-
covered by filtration and was successively washed with H2O, EtOH and
acetone. After drying (1108C, 6 h) the solid was collected as a white
powder.
À
1.4, 1.55 (m, 20H; 10ꢄCH2); 3.0, 3.1 (m, 8H; CH2 NH); 3.73 (q, 12H;
OCH2); 5.47 (2H; NH), 5.51 ppm (2H; NH); 13C NMR (200 MHz,
À
CDCl3): d = 159.13 (CO), 58.3 (OCH2), 42.8, 40.2 (2ꢄC N), 30.2, 29.3,
29.2, 26.8, 23.7 (5ꢄCH2), 18.2 (CH3), 7.6 ppm (Si CH2); 29Si NMR
À
Synthesis of L9: 13C CP MAS NMR: d = 11.6, 31.7, 43.4, 160.1 ppm; 29Si
(250 MHz, CDCl3): d = À45 ppm; IR (KBr pellet): n˜ = 958, 1079, 1104
(nSiO), 1576 (dNH), 1623 (nCO), 2853, 2932, 2976 (nCH), 3341 cmÀ1 (nNH); el-
emental analysis calcd (%) for C30H66O8N4Si2: C 54.02, H 9.97, N 8.40;
found: C 53.70, H 9.91, N 8.34.
CP MAS NMR: d = À38.4, À48.7, À57.8 ppm; IR (KBr, pellet): n˜
=
917 (nSiÀOH), 1030.4, 1128.2 (nSiÀO), 1584 (dNH), 1629.1 (nCO), 2855.5
(nCHsym), 2931.7 (nCHasym), 3355.4 cmÀ1 (nNH); N2 BET surface area:
13.1 m2 gÀ1; elemental analysis calcd (%) for C17H36O6N4Si2: C 45.51, H
8.09, N 12.49, Si 12.52; found: C 44.83, H 8.17, N, 12.25, Si 11.9.
1,12-Bis[(triethoxysilyl)propylureido]dodecane (P12): The preparation of
this compound was as described for P9, but starting from 1,12-diamino-
dodecane (1.6 g, 8 mmol) and g-isocyanatopropyltriethoxysilane (4 g,
16.1 mmol). After drying under vacuum (2ꢄ10À2 mm Hg), P12 was ob-
tained as a white solid. Yield: 5.2 g, 93%, m.p. 120–1218C; 1H NMR
(200 MHz, CDCl3): d = 0.56–0.65 (m, 4H; CH2Si), 1.19 (t, 18H; CH3),
Synthesis of L10: 13C CP MAS NMR: d = 11.6, 26.4, 31.5, 34.0, 42.8,
160.2 ppm; 29Si CP MAS NMR: d = À48.12, À57.02, À66.56 ppm; IR
(KBr, pellet): n˜ = 892, 1022, 1095 (nSiO), 1586 (dNH), 1623 (nCO), 2851
(nCHsym), 2927 (nCHasym), 3346 cmÀ1 (nNH); N2 BET surface area:
43.2 m2 gÀ1; elemental analysis calcd (%) for C18H38O6N4Si2: C 46.73, H
8.28, N 12.11, Si 12.14; found: C 46.88, H 8.24, N 12.12, Si 12.30.
À
1.4, 1.62 (m, 24H; 12ꢄCH2), 3.0, 3.13 (m, 8H; CH2 NH), 3.78 (q, 12H;
OCH2), 5.89 (2H; NH), 5.0 ppm (2H; NH); 13C NMR (200 MHz,
Synthesis of L11: 13C CP MAS NMR:
d = 12.2, 25.5, 33.3, 43.4,
À
CDCl3): d = 158.7 (CO), 58.4 (OCH2), 42.9, 40.5 (2ꢄC N), 30.3, 29.4,
160.3 ppm; 29Si CP MAS NMR: d = À38.9, À48.5, À57.3, À66.7 ppm; IR
29.3, 29.2, 26.8, 23.7 (6ꢄCH2), 18.3 (CH3), 7.6 ppm (Si CH2); 29Si NMR
À
(KBr, pellet): n˜ = 919, 1030, 1115 (nSiO), 1585 (dNH), 1625 (nCO), 2855
(250 MHz, CDCl3): d = À45.3 ppm; IR (KBr, pellet): n˜ = 958, 1079,
1168 (nSiO), 1577 (dNH), 1625 (nCO), 2851, 2930, 2976 (nCH), 3347 cmÀ1
(nNH); elemental analysis calcd (%) for C32H70O8N4Si2: C 55.29, H 10.15,
N 8.06; found: C 55.02, H 10.21, N, 8.26.
(nCHsym), 2932 (nCHasym), 3348 cmÀ1 (nNH); N2 BET surface area
:
60.4 m2 gÀ1; elemental analysis calcd (%) for C19H40O6N4Si2: C 47.87, H
8.46, N 11.75, Si 11.78; found: C 47.85, H 8.48, N 12.01, Si 11.7.
Undecane-1,11-dioyl dichloride: Under nitrogen, thionyl chloride (3.46 g,
29 mmol) was slowly added to a stirred solution of undecane-1,11-dicar-
Synthesis of L12: 13C CP MAS NMR: d = 11.1, 27.0, 31.5, 34.2, 42.9,
160.1 ppm; 29Si CP MAS NMR: d
=
À49, À58, À67 ppm; IR (KBr,
Chem. Eur. J. 2005, 11, 1527 – 1537
www.chemeurj.org
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1535

J. J. E. Moreau et al.
pellet): n˜ = 893, 1023, 1125 (nSiO), 1585 (dNH), 1625 (nCO), 2850 (nCHsym),
2923 (nCHasym), 3349 (nNH) cmÀ1; N2 BET surface area: 41.7 m2 gÀ1; elemen-
tal analysis calcd (%) for C20H42O6N4Si2: C 48.95, H 8.63, N 11.42, Si
11.45; found: C 48.51, H 8.74, N 11.49, Si 11.15.
Chem. Int. Ed., 1996, 35, 1420–1436; c) R. J. P. Corriu, Angew.
Chem. 2000, 112, 1432–1455; Angew. Chem. Int. Ed. 2000, 39, 1376–
1398; d) K. J. Shea, J. J. E. Moreau, D. Loy, R. J. P. Corriu, B. Boury,
in Functional Hybrid Materials (Eds.: P. Gomez-Romero, C. San-
chez), Wiley-VCH, 2004, pp. 50.
Fluoride-catalysed hydrolysis and polycondensation
[6] a) J. J. E. Moreau, M. Wong Chi Man, Coord. Chem. Rev. 1998, 178–
180, 1073–1084, and references therein; b) E. Lindner, T. Schneller,
F. Auer, H. A. Mayer, Angew. Chem. 1999, 111, 2288–2309; Angew.
Chem. Int. Ed. 1999, 38, 2155–2174; c) A. Adima, J. J. E. Moreau,
M. Wong Chi Man, J. Mater. Chem. 1997, 7, 2331–2333; d) A.
Adima, J. J. E. Moreau, M. Wong Chi Man, Chirality 2000, 5–6, 411–
420; e) P. Hesemann, J. J. E. Moreau, Tetrahedron: Asymmetry 2000,
11, 2183–2194; f) U. Schubert, N. Hꢅsing, A. Lorenz, Chem. Mater.
1995, 7, 2010–2027.
[7] R. J. P. Corriu, J. J. E. Moreau, P. Thꢀpot, M. Wong Chi Man, C.
Chorro, J.-P. Lꢁre-Porte, J-L. Sauvajol, Chem. Mater. 1994, 6, 640–
649.
[8] a) J.-C. Broudic, O. Conocar, J. J. E. Moreau, D. Meyer, M. Wong
Chi Man, J. Mater. Chem. 1999, 9, 2283–2285; b) S. Bourg, J.-C.
Broudic, O. Conocar, J. J. E. Moreau, D. Meyer, M. Wong Chi Man,
J. Mater. Chem. 2001, 11, 491–499; c) D. Meyer, O. Conocar, J. J. E.
Moreau, M. Wong Chi Man FR 2770153, 1999.
General method for the preparation of the amorphous bridged silses-
quioxanes A9–12: These materials were synthesised by hydrolysis of the
silylated bis-urea precursor in a mixture of ethanol, water and NH4F at a
molar ratio of Px/EtOH/H2O/NH4F 1:60:6:0.01. The reaction was carried
out as follows: Px was dissolved in freshly distilled ethanol containing
NH4F and water and the homogeneous solution was allowed to stand at
208C. Gelation had occurred after 24 h. After curing at 208C for 48 h,
the gel was powdered. After air drying, the solid was collected, washed
with EtOH and acetone and then dried (1108C, 6 h), yielding a white
powder.
Synthesis of A9: 13C CP MAS NMR: d = 10.2, 18.5, 30.1, 41.1, 161 ppm;
29Si CP MAS NMR: d = À58.7, À66.3 ppm; IR (KBr, pellet): n˜ = 941.2
(nSiÀOH), 1003, 1138 (nSiO), 1566.6 (dNH), 1657.1 (nCO), 2851.6 (nCHsym),
2928.2 (nCHasym), 3339.7 (nNH) cmÀ1; N2 BET surface area: 3.8 m2 gÀ1; ele-
mental analysis calcd (%) for C17H34O5N4Si2: C 47.41, H 7.96, N 13.01, Si
13.04; found: C 46.60, H 8.13, N 12.41, Si 12.35.
Synthesis of A10: 13C CP MAS NMR: d
= 10.3, 18.8, 30.0, 41.4,
[9] a) E. Z. Faraggi, Y. Sorek, O. Levi, Y. Avny, D. Davidov, R. Neu-
mann, R. Reisfield, Adv. Mater. 1996, 8, 833–835; b) F. Chaput, D.
Reihl, Y. Lꢀvy, J. P. Boilot, Chem. Mater. 1993, 5, 589–591; c) O.
Dautel, J.-P. Lꢁre-Porte, J. J. E. Moreau, M. Wong Chi Man, Chem.
Commun. 2003, 2662–2663; d) H. W. Oviatt, K. J. Shea, S. Kalluri,
Y. Shi, W. H. Steier, L. R. Dalton, Chem. Mater. 1995, 7, 493–498;
e) J. Livage, F. Babonneau, C. Sanchez, in Sol–gel Optics: Processing
and Applications (Ed.: L. C. Klein), Kluwer, Boston, 1994, p. 39;
f) D. Avnir, S. Braun, D. Levy, M. Ottolenghi, in Sol–gel Optics:
Processing and Applications (Ed.: L. C. Klein), Kluwer, Boston,
1994, p. 303.
159.9 ppm; 29Si CP MAS NMR: d = À59.0, À66 ppm; IR (KBr, pellet):
n˜ = 920, 1029, 1132 (nSiO), 1572 (dNH), 1645 (nCO), 2857 (nCHsym), 2931
(nCHasym), 3380 (nNH) cmÀ1; N2 BET surface area: 7 m2 gÀ1; elemental anal-
ysis calcd (%) for C18H36O5N4Si2: C 48.62, H 8.16, N 12.6, Si 12.63;
found: C 46.89, H 8.23, N 11.99, Si 12.0.
Synthesis of A11: 13C CP MAS NMR: d
= 11.0, 18.7, 30.3, 41.1,
58.,160.2 ppm; 29Si CP MAS NMR: d = À58.5, À66.6 ppm; IR (KBr,
pellet): n˜ = 917, 1026, 1131 (nSiO), 1571 (dNH), 1646 (nCO), 2858 (nCHsym),
2932 (nCHasym), 3384.8 (nNH) cmÀ1; N2 BET surface area: 2.2 m2 gÀ1; ele-
mental analysis calcd (%) for C19H38O5N4Si2: C 49.75, H 8.35, N 12.21, Si
12.25; found: C 48.23, H 8.37, N 12.19, Si 11.90.
[10] R. J. P. Corriu, J. J. E. Moreau, P. Thꢀpot, M. Wong Chi Man, Chem.
Mater. 1996, 8, 100–106.
[11] a) M. E. Davis, Nature 2002, 413, 813–821; b) M. J. MacLachlan, I.
Manners, G. A. Ozin, Adv. Mater. 2000, 12, 675–681.
Synthesis of A12: 13C CP MAS NMR: d = 10.7, 30.4, 40.3, 159.9 ppm;
29Si CP MAS NMR: d = À58.54, À66.48 ppm; IR (KBr, pellet): n˜
=
920, 1027, 1136 (nSiO), 1574 (dNH), 1646 (nCO), 2856 (nCHsym), 2932 (nCHasym),
3374 (nNH) cmÀ1; N2 BET surface area: 3.5 m2 gÀ1; elemental analysis
calcd (%) for C20H40O5N4Si2: C 50.82, H 8.53, N 11.85, Si 11.88; found: C
48.77, H 8.64, N 11.24, Si 11.3.
[12] a) C. T. Kresge, M. E. Leonowicz, W. J. Roth, J. C. Vartuli, J. S.
Beck, Nature 1992, 359, 710–712; b) J. S. Beck, J. C. Vartuli, W. J.
Roth, M. E. Leonowicz, C. T. Kresge, K. D. Schmitt, C. T.-W. Chu,
D. H. Olson, E. W. Sheppard, S. B. McCullen, J. B. Higgins, J. L.
Schlenker, J. Am. Chem. Soc. 1992, 114, 10834–10843; c) S. Inagaki,
Y. Fukushima, K. Kuroda, J. Chem. Soc. Chem. Commun. 1993,
680–681; d) Q. Huo, D. I. Margolese, U. Ciesla, P. Feng, T. E. Gier,
P. Sieger, R. Leon, P. M. Petroff, F. Schꢅth, G. D. Stucky, Nature
1994, 368, 317–321.
[13] a) S. Inagaki, S. Guan, Y. Fukushima, T. Ohsuna, O. Terasaki, J. Am.
Chem. Soc. 1999, 121, 9611–9622; b) S. Guan, S. Inagaki, T. Ohsuna,
O. Terasaki, J. Am. Chem. Soc. 2000, 122, 5660–5661; c) B. J. Melde,
B. T. Holland, C. F. Blanford, A. Stein, Chem. Mater. 1999, 11,
3302–3308; d) T. Asefa, M. J. MacLachlan, N. Coombs, G. A. Ozin,
Nature 1999, 402, 867–871; e) C. Yoshina-Ishii, T. Asefa, M. J. Ma-
cLachlan, N. Coombs, G. A. Ozin, Chem. Commun. 1999, 2539–
2540; f) M. J. MacLachlan, T. Asefa, G. A. Ozin, Chem. Eur. J. 2000,
6, 2507–2511; g) T. Asefa, C. Yoshina-Ishii, M. J. MacLachlan, G. A.
Ozin, J. Mater. Chem. 2000, 10, 1751–1755; h) A. Sayari, S. Hamou-
di, Y. Yang, I. L. Moudrakovski, J. R. Ripmeester, Chem. Mater.
2000, 12, 3857–3863; i) A. Stein, B. T. Melde, R. C. Schroden, Adv.
Mater. 2000, 12, 1403–1419; j) Y. Lu, H. Fan, N. Doke, D. A. Loy,
R. A. Assink, D. A. LaVan, C. J. Brinker, J. Am. Chem. Soc. 2000,
122, 5258–5261.
Acknowledgements
The authors gratefully acknowledge the “Ministꢁre de la Recherche”
(ACI 2000: Physicochimie de la matiꢁre complexe) and the CNRS for fi-
nancial supports.
[1] a) C. Sanchez, F. Ribot, New J. Chem. 1994, 18, 1007–1047; b) Or-
ganic/inorganic hybrid materials (Eds.: R. M. Laine, C. Sanchez,
C. J. Brinker, E. Giannelis), MRS Symp. vol. 519, 1998; c) Organic/
inorganic hybrid materials II, (Eds.: R. M. Klein, M. Deguire, F. Lor-
raine, J. Mark), MRS Symp. vol. 576, 1999; d) Organic/inorganic
hybrid materials III (Eds.: R. M. Laine, C. Sanchez, C. J. Brinker),
MRS Symp. vol. 628, 2000; e) J. J. E. Moreau, L. Vellutini, M.
Wong Chi Man, C. Bied, J-L. Bantignies, P. Dieudonnꢀ, J-L. Sauva-
jol, Mater. Res. Soc. Symp. Proc. 2002, 726, 235–242.
[2] Functional Hybrid Materials (Eds.: P. Gomez-Romero, C. Sanchez),
Wiley-VCH, 2004.
[14] a) A. Sayari, S. Hamoudi, Chem. Mater. 2001, 13, 3151–3168;
b) M. P. Kapoor, Q. Yang, S. Inagaki, J. Am. Chem. Soc. 2002, 124,
15176–15177.
[3] a) K. J. Shea, D. A. Loy, O. W. Webster, Chem. Mater. 1989, 1, 512–
513; b) K. J. Shea, D. A. Loy, O. W. Webster, J. Am. Chem. Soc.
1992, 114, 6700–6710.
[15] R. J. P. Corriu, J. J. E. Moreau, P. Thꢀpot, M. Wong Chi Man, J.
Mater. Chem. 1994, 4, 987–989.
[4] R. J. P. Corriu, J. J. E. Moreau, P. Thꢀpot, M. Wong Chi Man, Chem.
Mater. 1992, 4, 1217–1224.
[16] A. Shimojima, K. Sugahara, K. Kuroda, Angew. Chem. 2003, 115,
4191–4194; Angew. Chem. Int. Ed. 2003, 42, 4057–4060.
[5] a) D. A. Loy, K. J. Shea, Chem. Rev. 1995, 95, 1431–1442; b) R. J. P.
Corriu, D. Leclercq, Angew. Chem. 1996, 108, 1524–1540; Angew.
1536
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
Chem. Eur. J. 2005, 11, 1527 – 1537

Lamellar Bridged Silsesquioxanes
FULL PAPER
[17] a) B. Boury, R. J. P. Corriu, V. Le Strat, P. Delord, M. Nobili, Angew.
Chem. 1999, 111, 3366–3370; Angew. Chem. Int. Ed. 1999, 38, 3172–
3173; b) F. Ben, B. Boury, R. J. P. Corriu, P. Delord, M. Nobili,
Chem. Mater. 2002, 14, 730–738.
[18] S. Inagaki, S. Guan, T. Ohsuna, O. Terasaki, Nature 2002, 416, 304–
307.
[19] a) J. J. E. Moreau, L. Vellutini, M. Wong Chi Man, C. Bied, J. Am.
Chem. Soc. 2001, 123, 1509–1510; b) J. J. E. Moreau, L. Vellutini,
M. Wong Chi Man, C. Bied, J.-L. Bantignies, P. Dieudonnꢀ, J.-L.
Sauvajol, J. Am. Chem. Soc. 2001, 123, 7957–7958; c) N. Liu, K. Yu,
B. Smarsly, D. R. Dunphy, Y.-B. Jiang, C. J. Brinker, J. Am. Chem.
Soc. 2002, 124, 14540–14541; d) J. J. E. Moreau, L. Vellutini, M.
Wong Chi Man, C. Bied, Chem. Eur. J. 2003, 9, 1594–1999.
[20] J. J. E. Moreau, B. P. Pichon, M. Wong Chi Man, C. Bied, H. Pritz-
kow, J.-L. Bantignies, P. Dieudonnꢀ, J.-L. Sauvajol, Angew. Chem.
2004, 116, 205–208; Angew. Chem. Int. Ed. 2004, 43, 203–206.
[21] a) Y. Ono, K. Nakashima, M. Sano, J. Hojo, S. Shinkai, Chem. Lett.
1999, 1119–1120; b) J. H. Jung, Y. Ono, K. Hanabusa, S. Shinkai, J.
Am. Chem. Soc. 2000, 122, 5008–5009.
Schoonbeek, M. de Loos, H. Kooijman, A. L. Spek, R. M. Kellogg,
B. L. Feringa, Chem. Eur. J. 1999, 5, 937–950; c) M. de Loos, J. va-
n Esch, R. M. Kellogg, B. L. Feringa, Angew. Chem. 2001, 113, 633–
636; Angew. Chem. Int. Ed. 2001, 40, 613–616; d) V. D. Laan, B. L.
Feringa, R. M. Kellogg, J. Van Esch, Langmuir 2002, 18, 7136–7140.
[23] a) J. H. Jung, Y. Ono, S. Shinkai, Chem. Eur. J. 2000, 6, 4552–4557;
b) K. J. C. Van Bommel, A. Friggeri, S. Shinkai, Angew. Chem. 2003,
115, 1010–1030; Angew. Chem. Int. Ed. 2003, 42, 980–999.
[24] a) F. Lortie, S. Boileau, L. Bouteiller, Chem. Eur. J. 2003, 9, 3008–
3014; b) V. Simic, L. Bouteiller, M. Jalabert, J. Am. Chem. Soc.
2003, 125, 13148–13154.
[25] J. Jadzyn, M. Stockhauser, B. Zywucki, J. Phys. Chem. 1987, 91,
754–757.
[26] Sol–gel Science: The Physics and Chemistry of Sol–gel Processing
(Eds.: C. J. Brinker, G. W. Scherer) Acad. Press, New York, 1990,
pp. 116–136.
[27] P. Dieudonnꢀ, L. Vellutini, M. Wong Chi Man, J.-L. Bantignies, J.-L.
Sauvajol, C. Bied, J. J. E. Moreau, unpublished results..
[22] a) M. de Loos, J. van Esch, I. Stokroos, R. M. Kellogg, B. L. Feringa,
J. Am. Chem. Soc. 1997, 119, 12675–12676; b) J. van Esch, F.
Received: October 6, 2004
Published online: January 20, 2005
Chem. Eur. J. 2005, 11, 1527 – 1537
www.chemeurj.org
ꢂ 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1537