Redox active mesoporous hybrid materials by in situ syntheses with urea-linked triethoxysilylated phenothiazines

Article abstract of DOI:10.1002/asia.201000098

Triethoxysilyl functionalized phenothiazinyl ureas were synthesized and immobilized by in situ synthesis into mesoporous hybrid materials. The designed precursor molecules influence the structure of the final materials and the intermolecular distance of the phe-nothiazines. XRD and N₂ measurements indicate the presence ofhighly ordered two-dimensional hexag-onally structured functional materials, while the incorporation of the organic ompounds in the solid materials was proved by means of 13C and 29Si solid state NMR spectroscopy as well as by FT-IR spectroscopy. Upon oxidation with (NO)BF₄ or SbCl₅ stable pheno-thiazine radical cations were generated in the pores of the materials, which was detected by means of UV/Vis, emission, and EPR spectroscopies.

Full text of DOI:10.1002/asia.201000098

DOI: 10.1002/asia.201000098
Redox Active Mesoporous Hybrid Materials by In situ Syntheses with
Urea-linked Triethoxysilylated Phenothiazines
Zhou Zhou,[a] Adam W. Franz,[b] Sarah Bay,[b] Biprajit Sarkar,[c] Andreas Seifert,[d]
Piaoping Yang,[e] Alex Wagener,[a] Stefan Ernst,[a] Markus Pagels,[f]
Thomas J. J. Mꢀller,*[b] and Werner R. Thiel*[a]
Dedicated to Prof. Dr. Stefan Spange on the occasion of his 60th birthday
Abstract: Triethoxysilyl functionalized
phenothiazinyl ureas were synthesized
and immobilized by in situ synthesis
into mesoporous hybrid materials. The
designed precursor molecules influence
the structure of the final materials and
the intermolecular distance of the phe-
nothiazines. XRD and N2 adsorption
measurements indicate the presence of
highly ordered two-dimensional hexag-
onally structured functional materials,
while the incorporation of the organic
compounds in the solid materials was
proved by means of 13C and 29Si solid
state NMR spectroscopy as well as by
FT-IR spectroscopy. Upon oxidation
with (NO)BF4 or SbCl5, stable pheno-
thiazine radical cations were generated
in the pores of the materials, which was
detected by means of UV/Vis, emis-
sion, and EPR spectroscopies.
Keywords: electron
transfer
·
mesoporous materials
·
optical
materials · organic–inorganic hybrid
composites · phenothiazine
Introduction
[a] Dr. Z. Zhou, A. Wagener, Prof. Dr. S. Ernst, Prof. Dr. W. R. Thiel
Fachbereich Chemie
Since the discovery of mesoporous silicas in 1992,[1,2] re-
search on these materials has rapidly developed. They can
be readily obtained by the micellar condensation of silicic
acid derivatives. The pores of such solids can be used for dif-
ferent applications.[2,3] Chemical and physical manipulation
of the outer and the inner surface as well as in the bulk ma-
terial have been reported.[4] One of the main areas of re-
search in this field is related to applications in catalysis.[5]
However, because of pore sizes in the range of 2–30 nm,
these solids have also been used for the stabilization of
nanoparticles (quantum dots),[6] for the synthesis of nano-
wires,[7] or magnetic and optic materials.[8] Adsorption of re-
active species at the walls of those materials was used for
stabilization, almost similar to the isolation in the cavities of
zeolites. This idea was, for example, adopted to stabilize
photochromic dyes in mesoporous materials,[9] to stabilize
and organize chlorophyll a in order to mimic the energy
transfer and charge separation of photosynthesis,[10] to heter-
ogenize VO2+ and cytochrome c for oxygen activation,[11] to
investigate the photoinduced charge separation of pyrene[12]
and to stabilize benzene radicals in the mesopores of phenyl
substituted MCM-41.[13]
Technische Universitꢀt Kaiserslautern
Erwin-Schrçdinger-Str. Geb. 54, D-67663 Kaiserslautern (Germany)
Fax : (+49)631-2054676
E-mail: thiel@chemie.uni-kl.de
[b] Dr. A. W. Franz, S. Bay, Prof. Dr. T. J. J. Mꢁller
Institut fꢁr Organische Chemie und Makromolekulare Chemie
Heinrich Heine Universitꢀt Dꢁsseldorf
Universitꢀtsstr. 1, D-40225 Dꢁsseldorf (Germany)
Fax : (+49)211-8114324
E-mail: ThomasJJ.Mueller@uni-duesseldorf.de
[c] Dr. B. Sarkar
Institut fꢁr Anorganische Chemie
Universitꢀt Stuttgart
Pfaffenwaldring 55, D-70569 Stuttgart (Germany)
[d] Dr. A. Seifert
Institut fꢁr Chemie
Technische Universitꢀt Chemnitz
Strasse der Nationen 62, D-09107 Chemnitz (Germany)
[e] Dr. P. Yang
College of Materials Science and Chemical Engineering
Harbin Engineering University
Harbin 150001 (China)
[f] Dr. M. Pagels
Schlumberger Cambridge Research
High Cross, Madingley Road, Cambridge, CB3 0EL (UK)
Phenothiazines that represent nitrogen and sulfur contain-
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.201000098.
ing heterocycles[14] have gained different applications, such
Chem. Asian J. 2010, 5, 2001 – 2015
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2001

FULL PAPERS
as in pharmaceuticals.[15] An important feature of the pheno-
thiazine motif is a reversible one-electron oxidation process
with a low potential that leads to stable and deep colored
radical cations, as shown in Scheme 1.[16]
this procedure. First of all, the distribution of the organic
groups is generally not uniform within one channel, and sec-
ondly, the loading with larger and sterically demanding or-
ganic functionalities is often low, mainly constrained by dif-
fusion limitations. Therefore, in order to increase the pheno-
thiazine content in the pores and for the exploration of the
properties of these materials, such as intermolecular charge
transfer, an alternative method, providing a high content of
the electroactive chromophores and thus enabling intermo-
lecular electron transfer over a longer distance, was envi-
sioned. Hence, we decided to prepare the mesoporous
hybrid materials by a template-directed synthesis in the
presence of siloxylated phenothiazines. In this strategy, the
siloxane precursors act as building blocks for the construc-
tion of the main framework, whereas the organosiloxanes
contribute to both the silicate framework units and the or-
ganic functional groups on the surface. This one-step synthe-
sis can produce mesoporous solids with a high loading of or-
ganic functional groups and a homogeneous surface cover-
age within the channels of the materials. During the gelation
process, the organic moieties are supposed to extend into
the micelle causing an intramolecular phase separation.
Thus, the rational design of the organic precursors, which
must additionally be stable under the conditions of the ma-
terials synthesis, is of utmost importance. Here, we report
the synthesis and properties of urea-linked phenothiazines,
as well as their transformation into organic/inorganic meso-
porous materials by in situ synthesis, which results in a high
and uniform phenothiazine loading. In addition to their
structures, their electronic properties will also be presented.
Scheme 1. The reversible one-electron oxidation process of the pheno-
thiazine motif.
Consequently, phenothiazine derivatives have found ap-
plication in materials sciences as electrophoric sensors in
supramolecular systems for photoinduced electron transfer
(PET)[17] and as electron donors in electronically conducting
charge-transfer composites.[18] Furthermore, phenothiazine
polymers obtained by polycondensation play an important
role, for example, as electrochromic materials for displays.[19]
On the other hand, the low oxidation potential of polyphe-
nothiazines is responsible for its capability to act as an elec-
tron donor in fluorescent donor–acceptor chromophores,
which are of special use as emitters in organic light-emitting
diodes (OLED)[20,21] as well as for nonlinear optical and
electrooptical effects.[22]
The generation of efficient devices requires not only the
control of the electronic but also of the spatial properties of
a given system. It has been shown, for example, that the
electronic properties of p-conjugated materials strongly
depend on the interaction of the molecules and, thus, on
their intermolecular orientation.[23] From this point of view,
it appears to be beneficial to combine the properties of peri-
odically ordered inorganic mesoporous materials (strong ori-
entation of the pore system) and phenothiazines (electroop-
tic features) for a rational design of one-dimensionally
stacked redox active molecules. To date, there are only a
few reports on the physisorption of phenothiazines on silica,
presumably because of the weak forces between the aromat-
ic molecules and the silica surface,[24] which hampers the for-
mation of stable materials. It has been shown by means of
EPR spectroscopy that phenothiazine physisorbed on
porous silicas can form stable radical cations by photooxida-
tion, where the silica network might act as an electron ac-
ceptor.[25] Doping the support with transition metal ions or
using transition metal oxides as the support facilitates the
electron transfer process.[26] Furthermore, chlorinated hydro-
carbons can be used as electron acceptors,[25] a most favora-
ble aspect for the photochemical degradation of persistent
and ecotoxic compounds.
Results and Discussion
Synthesis and Properties of Urea-linked Triethoxysilylated
Phenothiazines
Ureas are synthesized by the straightforward addition of an
amine to an isocyanate. The major advantage of this ap-
proach lies in its highly atom-economical use of both the
starting materials that react almost quantitatively without
the formation of any by-products. Therefore, the retrosyn-
thetic analysis of urea-based phenothiazinyl building blocks
for their incorporation in mesoporous silica suggests the for-
mation of urea from a phenothiazinyl substituted amine
with a triethoxysilyl functionalized isocyanate (Scheme 2).
The amine in turn is readily accessible by reduction of the
corresponding phenothiazinyl cyano compound.
The phenothiazinyl nitrile 1 is easily prepared by Michael
addition of acrylonitrile to 10H-phenothiazine,[28] and the
cyano compounds 2 and 3 with extended p-conjugation are
obtained by Beller cyanation[29] in moderate to good yields
(Scheme 3).[30]
In a previous work, we introduced phenothiazines by co-
valent grafting on mesoporous MCM-41 and SBA-15 host
structures.[27] Although post-synthetic grafting is the most
popular way to anchor organic groups in a specific manner
to a silica surface, which finally results in organic–inorganic
hybrid materials, there are still some drawbacks related to
Upon standard reduction with lithium aluminium hydride
in refluxing diethyl ether, the cyano compounds 1–3 were
readily reduced to give the corresponding amines as amine
hydrochlorides 4–6 in moderate to good yields (Scheme 4).
With these amine hydrochlorides in hand, the stage was set
2002
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In Situ Syntheses of Mesoporous Hybrid Materials
1
ambiguously supported by H and 13C NMR spectroscopies,
mass spectrometry, and correct combustion analyses or high
resolution mass spectrometry.
In contrast to the previously reported carbamates,[27] urea
linked trialkoxysilyl functionalized compounds 7–9 reveal
some special properties. First, urea groups are inherently
able to form hydrogen bonds (vide infra). This interesting
property can be applied to assemble molecules into well-de-
fined supramolecular architectures[31] or to control the mor-
phology of the hybrid materials.[32] In addition, urea groups
can interact effectively with anionic species by hydrogen
bonding.[33] Based upon this feature, several sensors with
urea as the functional group have been reported.[34] For in-
stance, by linking a urea group to a fluorescent unit, these
molecules become suitable for detection of anionic species
by reverse photoinduced electron transfer (PET) by causing
a decrease in fluorescence intensity. Furthermore, urea has
frequently been used in the past for the generation of orga-
nosilicas.[35] Therefore, urea-based linkers were chosen to
induce a pre-organization of the phenothiazine moieties by
intermolecular hydrogen bonds in the micelle formation,
which leads to a stacked arrangement of the heteroaromatic
rings. Upon transfer into the final hybrid material as sug-
gested by Figure 1, facilitated electronic interaction could be
Scheme 2. Retrosynthetic analysis of urea-based phenothiazinyl building
blocks.
Scheme 3. Synthesis of (oligo)phenothiazinyl cyano derivatives 1–3.
Figure 1. An idealized illustration of the intermolecular electron transfer
between the phenothiazines.
anticipated. Another important aspect of the urea group is
its chemical and thermal stability. As mentioned before, for
the one-pot co-condensation synthesis of hybrid mesoporous
materials, a robust and firm organic precursor, which can
sustain under strong acidic and basic conditions, remains a
prerequisite. The electron donor/acceptor system in the con-
fined channel of mesoporous silica materials will ultimately
be formed upon partial oxidation.
Scheme 4. Reduction of 1–3 with LiAlH4 to the corresponding amines 4–
6.
for the introduction of the tri-
ethoxysilane linker by isocya-
nate addition.
The amine hydrochlorides 4–
6 were reacted in the presence
of triethylamine with 3-(trie-
thoxysilyl)propylisocyanate in
dry dichloromethane at 408C
under an argon atmosphere and
the corresponding ureas 7–9
were obtained in good to excel-
lent yields (Scheme 5). The
structures of the ureas were un- Scheme 5. Synthesis of triethoxysilyl functionalized (oligo)phenothiazine ureas 7–9.
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T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
Table 1. Selected absorption and emission spectra[a] and cyclic voltammetry[b] data of the (oligo)phenothiazine
ureas 7–9 and of the mesoporous hybrid materials 10–12.
dition of this mixture to the sur-
factant solution. A slow drop-
wise addition of this mixture to
the surfactant solution is impor-
tant. The addition of a certain
amount of methanol in the syn-
thesis of MCM-41 can increase
the degree of order of the mes-
oporous structure compared
compound
absorption lmax,abs [nm] (e)
emission lmax,em [nm]
Stokes shift Dn˜ [cmꢀ1
]
E00/+1 [mV]
7
8
9
257 (47100), 310 (7200)
260 (20300), 314 (3100)
267 (79000), 323 (30000)
250, 304
251, 307
248, 305
256, 308
255, 311
255, 310
255, 310
449, 511 (sh.)
459
458
436
438
388 (sh), 437
388, 450
456
378, 437
436
10000
10000
9100
10000
9800
690
669
595, 761
10-1
10-2
10-3
11-1
11-2
11-3
12-1
12-2
–
671[c]
9900
720[c]
10300
10200
9400
9900
9500
–
–
–
–
–
with
a
purely
aqueous
system.[38,39] For comparison,
the same method was used for
the synthesis of pure silica
MCM-41. After template ex-
traction with EtOH/HCl under
reflux conditions, the well-or-
dered MCM-41 hybrid materi-
268, 324
467, 512 (sh)
[a] Recorded in CH2Cl2, T=208C; [b] Recorded in CH2Cl2, T=208C, v=100 mVsꢀ1, electrolyte: (nBu4N)PF6,
Pt working electrode, Pt counter electrode, Ag/AgCl reference electrode. [c] Recorded in CH3CN, T=208C,
v=100 mVsꢀ1, electrolyte: (nBu4N)PF6, Pt working electrode, Pt counter electrode, Ag/AgCl reference elec-
trode.
The electronic properties of the phenothiazine ureas 7–9
have been investigated by absorption and emission spectros-
copy and by cyclic voltammetry (Table 1). The most charac-
teristic absorption of ureas in the UV region (two distinct
bands at 260 and 310 nm) is accompanied by a blue to
greenish blue fluorescence (broad unstructured bands with a
maximum at 450 nm and occasionally a shoulder at 510 nm)
for all representatives. With 10000 cmꢀ1, the Stokes shifts
are quite remarkable and can be attributed to significant
geometrical changes upon excitation for many phenothia-
zine derivatives from a highly non-planar ground state to a
largely planarized excited state.[36] Electrochemical data for
the presented phenothiazines were obtained by cyclic vol-
tammetry in the anodic region (up to 1.5 V). The first oxida-
tion potentials stemming from the most electron rich pheno-
thiazine core were found in the range from E00/+1 =595 mV
(diphenothiazine 9) to E00/+1 =690 mV (monophenothiazine
7) (Figure 2).
Synthesis and Properties of Urea-linked Phenothiazine/
MCM-41 Hybrid Materials
The urea unit is sufficiently stable to allow the co-condensa-
tion of the phenothiazinyl derivatives with tetraethoxysilane
(TEOS) in the presence of the base EtNH2 at 1008C and
prolonged reaction times. The main feature of this synthetic
route is the usage of EtNH2 instead of the conventionally
applied strong base NaOH, thus avoiding the incorporation
of Na+ ions into the mesoporous materials.[37] Under the
given conditions, MCM-41 type mesoporous materials fea-
turing a uniform two dimensional hexagonal channels was
formed. The pore size of these materials can easily be set-
tled between 2 to 3 nm by using CTAB as the template,
which provides an ideal matrix for the different phenothia-
Figure 2. A: cyclic voltammogram of 7; B: cyclic voltammogram of 8
(nBu4N+PF6ꢀ/CH2Cl2, 208C, n=100 mVsꢀ1
Pt-working electrode, Pt-
counter electrode, Ag/AgCl reference electrode); C: cyclic voltammo-
gram of 9; (nBu4N+PF6ꢀ/CH2Cl2, 208C, n=250 mVsꢀ1, Pt-working elec-
trode, Pt-counter electrode, Ag/AgCl reference electrode).
zine units. To obtain a uniform distribution of the pheno-
thiazine and to avoid phase separation during the formation
of the mesoporous structure, TEOS and 7 (or 8, 9) were
first dissolved in a small volume of methanol prior to the ad-
,
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In Situ Syntheses of Mesoporous Hybrid Materials
during the template extraction process.[42] The textural pa-
rameters of all the hybrid materials are summarized in
Table 2. Exemplarily, the XRD patterns of the compounds
10 with different amounts of phenothiazine (10-1: 0.33; 10-2:
0.54; 10-3: 0.77 mmolgꢀ1) are shown in Figure 3.
Scheme 6. In situ synthesis of the mesoporous hybrid materials 10, 11,
and 12 with CTAB as the template.
als 10–12 were obtained (Scheme 6). To determine the influ-
ence of the concentration and molecular structure of pheno-
thiazine on the configuration of the hybrid mesoporous ma-
terials, various concentrations and well-designed phenothia-
zine moieties were employed (Table 2).
Figure 3. A: Powder XRD pattern of compounds 10; a) 10-1, b) 10-2,
and c) 10-3. B: magnified signals at 38<2V<78.
Compound 10-1 showed four
Bragg diffraction peaks similar
Table 2. Textural parameters of the hybrid materials 10, 11, and 12 derived from nitrogen adsorption–desorp-
to MCM-41, which indicated a
long-range ordered hexagonal
mesostructure. The d100 value
(4.38 nm) increased slightly
compared to neat MCM-41,
presumably caused by an in-
creased micelle diameter at the
given concentration.[43] The
characteristic (100) peak shifts
slightly to larger 2V values at
higher concentrations of precur-
sor 7, which corresponds to a
decrease in the d spacing (10-2:
4.23; 10-3: 4.20 nm). In these
cases, 7 significantly expels the
surfactant in the hydrophobic
tion analysis or powder X-ray diffraction and loading of phenothiazines in the hybrid materials.
[a]
[b]
[c]
[d]
[e]
sample
d100
a0
SBET
[m2 gꢀ1
Vp
[cm3 gꢀ1
Dp
wt[f]
[nm]
C[g]
[mol%]
content of phenothiazine[h]
[mmolgꢀ1
[wt%]
[nm]
[nm]
G
]
E
]
[nm]
N
R
]
ACHTUNGTRENNUNG
MCM-41
10-1
10-2
10-3
11-1
11-2
11-3
12-1
12-2
4.30
4.38
4.23
4.20
4.05
4.00
3.98
4.04
3.96
4.96
5.06
4.88
4.85
4.68
4.62
4.60
4.66
4.57
1123
1040
914
700
991
766
638
761
632
0.98
0.85
0.69
0.42
0.78
0.58
0.51
0.65
0.57
2.83
2.48
2.41
2.25
2.65
2.68
2.69
2.64
2.58
2.14
2.58
2.48
2.60
2.02
1.94
1.90
2.02
1.98
–
–
–
17.8
35.0
53.6
15.7
26.4
37.1
18.6
25.7
0.33
0.54
0.77
0.26
0.40
0.54
0.28
0.35
13.0
21.2
30.2
11.7
17.9
24.2
20.4
25.2
p
[a] d100: d(100) spacing. [b] a0 =2d100
/
3. [c] SBET: BET surface area. [d] Vp: Pore volume. [e] Dp: Pore diame-
ter. [f] wt: Wall thickness (a0ꢀDp). [g] Molar ratio of precursor/CTAB. [h] Calculated from the nitrogen con-
tent (CHN analysis).
Structural Characterization and Properties of the Hybrid
Materials
phase during the formation of the micelles.[44] This disturbs
the surfactant cooperation with the inorganic species by bal-
anced Coulomb interactions to form micelles fully covered
with silica species. Therefore, the unit cell will contract after
the hydrothermal reaction.[45] Parallel to the increase of the
phenothiazine content, the relative intensities of all diffrac-
tion peaks decrease, particularly the peaks at higher angles.
For 10-3, the second order peaks (110) and (200) are over-
lapping, and the peak of the (210) plane is nearly undetecta-
ble. This feature may partially be attributed to a decrease in
the mesoscopic order of the materials, and partially because
of the contrast matching between the amorphous silicate
framework and organic moieties which are located inside
the channels.[5d,43,44,46] While the samples 11-1, 11-2, and 11-3
show a similar influence of the phenothiazine concentration
on the XRD pattern and on the cell parameters (see Sup-
porting Information), the biphenothiazine series, 12-1 and
Powder X-ray Diffraction
Powder XRD was carried out to elucidate the structural or-
dering of the mesoporous materials. For comparison, neat
MCM-41 was synthesized and analyzed. The powder XRD
patterns of all materials are given in the Supporting Infor-
mation. Generally, all samples exhibited typical reflections
of a material possessing two-dimensional hexagonal p6mm
symmetry.[1b,40] The intensity of the reflections was found to
increase after the extraction of the template CTAB, which
can be assigned to an enhancement of the contrast density
between the framework and pore channels.[41] For neat
MCM-41, an increase in the d100 spacing from 4.27 to
4.30 nm was observed. This can be attributed to an ongoing
condensation of silicon species in the material framework
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T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
12-2, are different. The XRD pattern of 12-1 (0.28 mmol of
biphenothiazine per g) presents a normal peak pattern with
clearly detectable (100), (110), (200), and (210) reflections
typical for two-dimensional hexagonal p6mm symmetry (see
Supporting Information). Compound 12-2 shows an intense
(100) peak and a peculiar intense (200) peak overlapping
the (110) peak. This indicates the formation of a distorted
hexagonal structure or an intermediate phase between a
hexagonal and a lamellar configuration.[47,48] In the litera-
ture, this has been explained with a distorted hexagonal
structure, which might be because of the amorphous nature
of the mesoporous silica framework.[49] The silica species in
the pore size distribution curves indicate a slight increase of
the pore size, which is in contrast to the situation discussed
for the samples 10. This could be related to the process of
the mesostructure formation. The behavior of samples 12 is
again different. Here, a second inflection appears at P/P0
close to 0.42–1, which displays a H4-type hysteresis loop in
the desorption branch of the isotherm. This feature is char-
acteristic of slit-like pores, which may be the result of textur-
al porosity within the particles or because of an intersecting
disorder of the materials.[55]
By analyzing the textural parameters summarized in
Table 2, a general conclusion can be deduced. The d100 spac-
ings, the specific BET surface areas, and the pore volume
are reduced with increased amounts of organic silane in the
reaction mixture. A similar behavior was observed by others
who investigated the loading with pendent organic groups
by applying the co-condensation method.[59,60,61] An increase
in the pore filling organic component decreases the pore
volume and the specific surface areas, which is easily under-
standable, whilst the reasons for a decrease in d100 spacing
upon increase of the organic precursor concentration are
not so easily understood. Some studies ascribe this trend to
different interactions between the cationic surfactant mole-
cules and the silicate or organosilicate precursors during the
hydrothermal reaction.[43,62] In our case, the reaction mix-
tures leading to 10, 11, and 12 contain organosilicates with
different phenothiazine fragments, which could influence
the process of the mesophase formation. In this process, in-
organic species and organic molecules will interact. The mi-
celle interface curvature depends on Coulomb attraction/re-
pulsion, van der Waals interactions, hydrogen bonds, and co-
valent bonds between inorganic/organic units.[45,63] The syn-
thesis of 10, 11, and 12 was performed at pH ~13, while the
aqueous isoelectric point (IEP) of the silica species was at
pH ~2.[64] Therefore, the silicate species are negatively
charged, and will interact with the positively charged surfac-
tant head groups by Coulomb attraction. The inorganic spe-
cies/organic surfactant interface will thus be influenced by
the location and concentration of the phenothiazine precur-
sor, which again would be influenced by the molecular size
and shape of the phenothiazinyl substituted silanes. During
the micelle formation, the siloxane group of the precursor
will be embedded in the inorganic layer, while the pheno-
thiazine group might be located near this interface or reach
the internal core depending on the molecular geometry of
the precursor.[64]
ꢀ ꢀ
this type of structural materials have a wide range of Si O
Si bond angles, which are much more flexible than in crys-
talline zeolites.[50] We assign this behaviour to the large mo-
lecular structure of precursor 9, which could disturb not just
the micelles but also the final structure of the silica frame-
work to some degree. The presence of a transition phase
can be traced back to the classical surfactant pair packing
parameter, g=V/a0l, in which a variation of g can be in-
dexed to phase transitions and different geometries of the
mesophase products.[50] For 12-2, the high content of 9
would dramatically increase the hydrophobic volume V, and
thus the value of g is increased, which results in a decrease
of surface curvature and thus in a mesophase transition be-
tween the hexagonal and the lamellar structure.[51,52]
N2 Adsorption/Desorption
The nitrogen adsorption isotherms for the extracted pheno-
thiazine-urea functionalized hybrid materials are all present-
ed in the Supporting Information, and the corresponding
data are listed in Table 2. All the eight samples display typi-
cal IV isotherms (definition by IUPAC),[53] with a sharp ca-
pillary condensation step in the low P/P0 range of 0.2 to 0.4,
which confirms the ordered mesoporous structure of these
materials. In this region, only compound 10-1 exhibited a
narrow hysteresis loop in the steep low-pressure region,
which may be because of nitrogen occupying the regions be-
tween adjacent organic groups and the silica wall.[43,54] A fur-
ther narrow H4 type hysteresis loop observed for 10-1 and
10-2 on the horizontal portion (from P/P0 0.45–0.95) can be
linked to uniform slit-shaped pores.[55,56]
Generally, quite narrow pore size distributions are ob-
served, which demonstrates the presence of uniform pores.
In combination with the increase of organic material in the
samples, the volume of total adsorption continuously de-
creases, which can be attributed to a decline in the surface
area and the total pore volume. For the samples 10, the posi-
tion of the capillary condensation step gradually shifts from
a relative pressure of ~0.24 to ~0.19, which indicates a sys-
tematic decrease of the pore size,[57] which as expected cor-
roborates with the decrease of the d100 values and the unit
cell parameter a0 determined by XRD (see above). For the
samples 11, completely reversible isotherms and the absence
of any hysteresis loops, indicate ordered mesoporous materi-
als with uniform pore sizes and ordered arrangements of cy-
lindrical channels without any intersecting disorder.[58] Here,
In the case of 7, the phenothiazine core should be located
closer to the interface, which results in the reduction of the
silanol groups in this region. Thus, less surfactant molecules
are required for charge balance, which leads to a remark-
able contraction of the cylindrical micelle size in the hybrid
materials with increasing precursor concentrations. In con-
trast, compound 8 bears the urea linker in the 3-position
and the hexyl chain in the 10-position. This molecular struc-
ture is favorable for interaction with the template molecules
through hydrophobic interactions. Therefore, the phenothia-
zine group will be drawn further into the inner part of the
2006
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In Situ Syntheses of Mesoporous Hybrid Materials
surfactant micelles and the influence of the concentration of
8 on the interface layer will not be as significant as in the
case of 7.
FT-IR Spectroscopy
ꢀ
The infrared absorptions of the N H and the C=O groups
in urea are quite sensitive to hydrogen bonding.[68] In solu-
tion, intermolecular hydrogen bonding is concentration de-
pendent, that is, the higher the concentration of the sample,
the greater the extent of hydrogen bonding.[69] We used this
feature to determine the interaction of the urea-linked phe-
nothiazines in the organic/inorganic hybrid materials.
Electron Microscopy
Transmission electron microscopy (TEM) is an indispensa-
ble tool for the characterization of the hybrid materials. It
provides direct evidence for the structural ordering of the
materials in the form of images, and helps in the direct dis-
covery of intrinsic pore structures of hybrid materials.[65]
TEM and SEM images of all samples are included in the
Supporting Information. The mesostructure depends on the
concentration and the molecular structure of the precursor
in the reaction mixture. Especially the hybrid materials 10-1
and 11-1 show uniform and highly ordered structures. Con-
sistent with the XRD results, an increase in the precursor
concentration slightly reduces the ordering of the materials.
The mesostructure changes significantly for the diphenothia-
zine derived system 12-2. While 12-1 still exhibits hexagonal-
ly arranged pore channels, 12-2 presents a certain type of
nanofilament elongated specifically along the channel direc-
tion of the hybrid mesostructure. Based on TEM (Figure 4)
and XRD data, an explanation for the formation of this
First, the concentration dependence of the IR spectra of
precursor 7 was studied in a CH2Cl2 solution. Figure 5 pres-
Figure 4. TEM images of the hybrid mesoporous material 12-2.
Figure 5. FT-IR spectra of 7 in CH2Cl2; concentrations: 2.0, 6.0, 12.0,
18.0, 24.0, 30.0, 36.0, 50.0 mmolLꢀ1
.
structure can be proposed. The large hydrophobic bipheno-
thiazine precursor 9 can undergo p–p interaction and the
parallel molecules can protract vertical to the cross-section
of the micelles. Hence, long tubular-type micelles can be ex-
pected, which is in accordance with the extremely long
channels observed by TEM and the distorted transition
structure derived from the XRD data.
Obviously, differences in the microscopic regime during
the gelation process will also have an influence on the mac-
roscopic morphology of the products.[66,67] This can also be
found for the phenothiazine modified hybrid materials, al-
though most of the observed morphologies are not as uni-
form as reported for certain examples in the literature. This
is because of our synthetic process, which includes a long hy-
drothermal treatment. However, this is favourable for the
complete hydrolysis of the silica species and for achieving a
high loading of organic moieties. Powdery products are ob-
tained rather than morphologically uniform nanoscale mate-
rials. SEM pictures of all samples are included in the Sup-
porting Information.
ents the concentration dependence of nNꢀ and the amide I
H
[69]
(nC O) and the amide II band (dNꢀ
)
of precursor 7 in
=
H
CH2Cl2 solution. The nNꢀ at around 3440 cmꢀ1 is typical for
H
free ureas and the nNꢀ at about 3375 cmꢀ1 can be assigned
H
to hydrogen bonding urea groups.[68] Obviously, this band in-
creased with increasing concentration, and simultaneously,
the center of this band shifted slightly to lower wavenum-
bers and an additional shoulder at around 3325 cmꢀ1 was ob-
served at the highest concentration. Hydrogen bonding
weakens the C=O bond and thus leads to a decrease of the
stretching frequency. Therefore, the nC
at around
=
O
1672 cmꢀ1 can be assigned to free urea groups and the band
at about 1645 cmꢀ1 to the intermolecular hydrogen bonded
urea groups. Similarly dNꢀ was also observed as two bands
H
at about 1536 and 1571 cmꢀ1. The absorption at lower wave-
numbers corresponds to free urea groups, and the absorp-
tion at higher wavenumbers to urea units involved in inter-
ꢀ
molecular hydrogen bonds. A decrease in Dn (amide I
amide II) was clearly observed and is in agreement with
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T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
dominant hydrogen bonding urea groups in nonpolar organ-
ic media.[70]
Figure 6 (spectrum a) shows the absorbance of the neat
precursor 7. Comparison with the solution spectra indicates
that the peak at 3440 cmꢀ1, characteristic for free urea
groups, has disappeared. Additionally, a significant shift of
respectively. The corresponding Dn is 55 cmꢀ1, which is in
fact a little larger than the value found for neat 7 (Dn=
45 cmꢀ1), but still much smaller than for free urea (Dn=
120 cmꢀ1). This indicates the presence of hydrogen-bound
urea groups in the hybrid materials. Furthermore, the low
loading
samples
10-1
(0.33 mmolgꢀ1)
and
10-2
(0.54 mmolgꢀ1) present two small peaks around 1542 and
1558 cmꢀ1, which disappear in the high loading sample 10-3
(0.77 mmolgꢀ1). This implies a higher degree of hydrogen
bonding in the latter sample, which can be assigned to
larger aggregates of phenothiazines interacting through hy-
drogen bonds.
For neat 9, the Dn value (58 cmꢀ1) still indicates hydrogen
bond interactions, although it is significantly larger than for
neat 7 (44 cmꢀ1) and 8 (43 cmꢀ1). This may be attributed to
the two phenothiazine groups in 9 which will hamper the in-
teraction of the urea groups by increased steric hindrance.
In the IR spectra of the hybrid materials 12, a series of nC
=
O
Figure 6. FT-IR spectrum (KBr) of a) 7, b) 10-1, c) 10-2, and d) 10-3
(right side inset: amide I and amide II bands).
and dNꢀH vibrations indicated differently bound urea units.
The most significant IR data of the precursors 7–9 and
the hybrid materials 10–12 are summarized in Table 3. Gen-
erally, the Dn values of the neat organic ureas are smaller
than those found for the hybrid materials, which indicates
that intermolecular hydrogen bond interactions are de-
creased in these materials. This phenomenon can be easily
rationalized, because the average distance of molecules in
the hybrid materials should be larger than in the pure pre-
cursor.
the signals assigned to hydrogen bound urea groups[68,69]
from 3375 cmꢀ1 in solution to 3354 and 3308 cmꢀ1 in the
solid state could be observed, which indicates at least two
ꢀ
different types of N H bonds. Furthermore, strong absorp-
tions were found for nC and dNꢀH. In neat solid 7, nC was
=
O
=
O
found at 1625 cmꢀ1 and dNꢀ at 1580 cmꢀ1. Both bands are
H
redshifted compared to the solution data, which is in agree-
ment with a higher degree of intermolecular hydrogen bond-
ing in the solid state. Furthermore, Dn is significantly small-
er (45 cmꢀ1) than for free urea groups (120 cmꢀ1)[70] and
even smaller than the Dn of precursor 7 in solution
(74 cmꢀ1). All these observations can be correlated to a
strong association of urea groups by hydrogen bonding in
the solid state.
The IR spectra of 10-1, 10-2, and 10-3 are also shown in
Figure 6. They are typical for all hybrid materials discussed
in this manuscript (see the Supporting Information) and
shall be discussed exemplarily here. Generally a broad ab-
sorption is observed in the range of 3600–3200 cmꢀ1, which
can be assigned to the nOH stretching vibration of the hydro-
gen-bound silanol groups.[71] Further broad bands at 1300–
1100 cmꢀ1 are attributed to the asymmetric vibration of the
Table 3. IR data of the precursors 7–9 and the hybrid materials 10–12.
[a]
sample
nNꢀ
nC
dNꢀ
Dn
(min, max)
n [nm2]
d [nm]
–
=
O
H
H
7
3354
3308
–
1625
1628
1628
1580
45
–
10-1
10-2
1573
1558
1573
1558
1573
1577
1576
1559
1543
1576
1559
1543
1576
1559
1543
1575
1574 (sh)
1568
1559
1542
1574 (sh)
1568
1559
1542
55
70
55
70
55
43
60
102
0.19
0.36
2.27
1.68
–
10-3
8
11-1
–
1628
1620
1645
1636
0.66
–
0.16
1.23
–
2.51
3308
–
11-2
11-3
–
–
1645
1636
60
102
0.31
0.51
1.80
1.40
ꢀ ꢀ
Si O Si units of the silica network. The absorption at
955 cmꢀ1 derives from the stretching vibration of the surface
1645
1636
60
102
ꢀ1
ꢀ
Si O groups, and the peak at 800 cm is attributed to the
ꢀ ꢀ
symmetric vibration of Si O Si. A strong absorption at
9
12-1
3358
–
1633
1645
1636
58
62
103
–
0.22
–
2.12
460 cmꢀ1 is assigned to the bending vibration of Si O Si.
[72]
ꢀ ꢀ
In addition to these signals typical for silica, some further
absorptions can be assigned to the organic moieties. The
ꢀ
stretching vibration of aliphatic C H groups appears at
12-2
–
1645
1636
62, 103
0.33
1.73
around 2980–2850 cmꢀ1 (not shown in Figure 6) and the ab-
sorption at 1470 cmꢀ1 arises from the C H deformation vi-
ꢀ
bration. The typical urea nNꢀ vibration is covered by the
H
ꢀ
Si OH vibrations. However, the characteristic nC and dNꢀ
=
O
absorptions can be observed at ~1629 cmꢀ1 and ~1572 cmꢀ1H,
[a] Dn=amide Iꢀamide II (Dnmin =amide Iminꢀamide IImax, and Dnmax
amide Imaxꢀamide IImin).
=
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Chem. Asian J. 2010, 5, 2001 – 2015

In Situ Syntheses of Mesoporous Hybrid Materials
tween the phenothiazine precursor 7 and TEOS during the
Solid State NMR Spectroscopy
co-condensation process.[75]
13C CP-MAS NMR spectroscopy provides information on
the integration of the organic component in the hybrid ma-
terials. As an example, the spectrum of 10-2 is shown in
Figure 7, with dashed lines representing the resonances of
Electronic and Optical Properties of the Hybrid Materials
All hybrid material samples 10-1, 10-2, and 10-3 were char-
acterized by solid state cyclic voltammetry. The powdered
hybrid materials were abrasively immobilized on a glassy
carbon electrode and the cyclic voltammograms were re-
ꢀ
corded in acetonitrile solution with 0.1m nBu4N+PF6 as
supporting electrolyte. Figure 8 shows a series of cyclic vol-
tammograms obtained from 10-3 with varying scan rates
(see the Supporting Information for the data of 10-1 and 10-
2).
Figure 7. A) 13C CP-MAS NMR and B) 29Si CP-MAS NMR spectrum of
10-2; the dashed lines in the 13C NMR spectrum give information on the
position and the relative intensities of the resonances in the solution
13C NMR spectrum of 7.
precursor 7 in solution (for the solid state 13C NMR spectra
of all other hybrid materials, see the Supporting Informa-
tion). Obviously, the resonances of the solid state material
are quite similar compared to the solution spectrum. The
resonance at d=7.6 is assigned to the carbon atom bound to
ꢀ
silicon, which confirms that there is no cleavage of the C Si
bond during the synthesis. Two sharp peaks at d=16 and 60
ꢀ
are assigned to the residual Si OCH2CH3 groups. The reso-
nance at d=~40 can be assigned to the carbon atoms bound
to the urea unit, which demonstrates the stability of the
urea group under the co-condensation conditions. Several
signals in the low field region (d=~130–114) are typical for
an electron rich aromatic system and can be assigned to the
carbon nuclei of the phenothiazine core. Compared to the
spectrum obtained in solution, a small shift of the resonance
of the C=O group (d=~158) to lower field is ascribed to hy-
drogen bonding of the urea group.
Figure 8. A) Cyclic voltammograms with varying scan rates (0.01, 0.02,
0.04, 0.06, 0.08, 0.10, 0.20, 0.40, 0.60, 0.80, 1.00 Vsꢀ1) of an electrode
modified with 10-3 (0.1m (nBu4N)PF6, CH3CN, RT). B) Plot of oxidation
peak currents versus scan rates, linear regression analysis gives: y=
8·10ꢀ5x+1·10ꢀ7, R2 =0.9997.
Solid state 29Si CP-MAS NMR spectra provide informa-
tion on the silicon environment and the degree of organic
functionalization. Figure 7 shows the 29Si CP-MAS NMR
spectrum of 10-2 (for the solid state 29Si NMR spectra of all
other hybrid materials, see the Supporting Information). A
peak of low intensity (d=ꢀ92) corresponds to geminal
A potential sweep with a 10-3 modified GC electrode at a
scan rate of 0.1 Vsꢀ1 reveals an oxidation wave at a poten-
tial of 762 mV and a reduction wave at a potential of
678 mV against Ag/AgCl. The half-wave potential of this re-
versible one electron transfer is 720 mV, with a peak separa-
tion of 84 mV. Variation of the scan rate in the range of
0.01–1.0 Vsꢀ1 still gives reversible redox signals with the
peak potentials being fairly constant, and the peak currents
increasing with increasing scan rate.
There are two possible pathways to realize the electron
transfer in these hybrid mesoporous materials.[76] One is a
direct electron transfer from the electrochemically active
species to electrode surface, which would require pro-
nounced mobility of the redox sites. This mechanism is usu-
ally observed for redox active sites physically adsorbed in
mesoporous materials.[77] A second possible mechanism is a
(HO)2SiACHTUNGTRENNUNG
(SiO)2 (Q2) sites while the most intense resonance
of the spectrum (d=ꢀ101) is assigned to isolated (HO)Si-
ACHTUNGTRENNUNG
(d=ꢀ110) is ascribed to Si
(SiO)4 (Q4) centers and com-
ACHTUNGTRENNUNG
pletes the characterization of the silica bulk material.[73]
Usually three signals at d=ꢀ49, ꢀ59, and ꢀ69 can be as-
1
ꢀ
ꢀ
signed to organo silicon species R Si(HO)
G
2
Si(HO)
(OSi)2 (T ), and RSi
(OSi)3 (T3), respectively.[74]
ꢀ
Here, a broad band centered at d=ꢀ65 was observed,
ꢀ
which means that the major Si C species are of the T and
T3 type. This indicates quite a complete cross-linking be-
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T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
long-range electron transfer by the immobilized redox
active sites to the electrode surface through electron ex-
change between adjacent redox centers (electron
hoping).[78,79] Since in 10-3, the electrochemical active cen-
ters (phenothiazines) are covalently fixed in the pores of the
mesoporous silica matrix, the latter mechanism obviously
appears to be more plausible. Further evidence for electron
hopping is presented in Figure 8 (bottom), where the oxida-
tion peak currents are plotted against the scan rates showing
a linear relationship. This also indicates surface bound redox
centers.[77] In a multi-sweep experiment, 10-3 showed high
stability (see the Supporting Information). After 100 scans,
the overall current just slightly decreased, probably because
of mechanical loss of the powdery material from the elec-
trode surface. This is different from a diffusion controlled
electrochemical reaction with a supported material on the
electrode. In that case, the current should decrease quickly,
owing to diffusion of redox active species into the electro-
lyte.[77,80]
the bands can be considered with an increased loading of
phenothiazine (see the Supporting Information), which may
be attributed to weak p-electron interactions with surface
[83]
ꢀ
bound Si OH groups, or may be a result of H-aggrega-
tion, which usually is accompanied with a further hypsochro-
mic shift.[36,82,84,85]
Figure 9 also shows the emission spectra of 10-1, 10-2, and
10-3 (blue lines). All the emissions were located at ~437 nm,
which had shifted hypsochromically compared to the data of
7 in CH2Cl2 solution (peak maximum: 449 nm; shoulder:
511 nm). The Stokes shift is ~10000 cmꢀ1. Interestingly, a
second emission could be observed in the spectra of 10-2
(small shoulder) and 10-3 (shoulder: ~515 nm). As already
discussed for the absorption of the samples 10-1, 10-2, and
10-3, aggregation also affects the luminescence by a substan-
tial blue shift of the emission bands, presumably caused by
p-stacking, which is essentially absent in solution. Therefore
the silanol groups on the surface of the materials would
have a strong influence on such TICT states.
The UV/Vis spectra of the hybrid material samples 10-1,
10-2, and 10-3 are illustrated in Figure 9 (for the UV/Vis
spectra of all other hybrid materials, see the Supporting In-
formation, characteristic data are summarized in Table 1).
The hybrid materials undergo formation of surface bound
radical cations when treated with oxidizing agents
(Scheme 7). Oxidation was carried out with the one-electron
Scheme 7. Oxidation of the mesoporous phenothiazinyl hybrid materials.
Figure 9. UV/Vis spectra (black lines) of 10-1 (A), 10-2 (B) and 10-3 (C)
of the corresponding radical cationic samples 10-1-BF4, 10-2-BF4, 10-3-
BF4 (red lines), 10-1-SbCl6, 10-2-SbCl6, 10-3-SbCl6 (green lines) and emis-
sion spectra of 10-1, 10-2, and 10-3 (blue lines). The inset picture demon-
strates the color change caused by the oxidation of 10-1 using NOBF4 in
suspension and for the corresponding solid.
oxidants SbCl5 and NOBF4 in CH2Cl2 suspension, leaving
ꢀ
ꢀ
SbCl6 and BF4 as the counter ions, respectively. For the
materials 10-1, 10-2, and 10-3, a color change to red was ob-
served during the oxidation reaction (Figure 9, inset). This
color change manifests in an absorption band around
515 nm typical for phenothiazine radical cations. Additional-
ly, a broad absorption band in the NIR region could be ob-
served. The intensity of these bands increases with increas-
ing loading of phenothiazine. Such NIR bands have often
been associated with a charge resonance transition of cofa-
cially oriented aromatic donor/acceptor dyads.[86] It is also
well known that electron transfer between the phenothia-
zine moiety and its radical cation can occur.[16c,d] Further-
more, these NIR bands are absent in monophenothiazine
modified mesoporous materials obtained by post synthetic
grafting.[27b] Thus, we assign this NIR bands to an intermo-
lecular charge transfer (CT), which demonstrates that the
The three samples present two absorptions in the UV. Com-
pared to the spectrum of precursor 7 in CH2Cl2, a slight hyp-
sochromic shift of the absorption maxima can be observed
for the hybrid materials, which can be attributed to the in-
teractions between the silica surface and the phenothiazine
core or a consequence of a one-dimensional H-type aggrega-
tion of phenothiazine molecules in the channel of the meso-
porous material (H-aggregate, face-to-face arrange-
ment).[81,82] A change in the phenothiazine content causes no
shift of the absorption maxima. Only a slight broadening of
2010
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In Situ Syntheses of Mesoporous Hybrid Materials
co-condensation method is an appropriate way to achieve
strongly intermolecularly coupled phenothiazine complexes.
It is worthwhile to mention that the resulting deeply col-
ored materials retain their color under ambient temperature
for several weeks when stored under an atmosphere of dry
nitrogen, which indicates high stability of the radical cations
in the mesoporous hybrid materials. The red color fades to
pink when the materials are exposed to air at room temper-
ature for 3 days. The absorption spectra of these exposed
materials are shown in the Supporting Information. The typ-
ical absorptions of the phenothiazine radical cations are still
present in the absorption spectrum but with decreased in-
tensity. Compared to the freshly generated materials, a
novel and intense peak at 344 nm was detected, which might
be associated with a new compound generated by a pheno-
thiazine radical cation consuming reaction that leads to the
corresponding S-oxide through disproportionation of the
radical cation.[87]
MCM-41 following an in-situ methodology. The highly or-
dered hexagonal mesoporous structures of the materials
were confirmed by XRD and N2 adsorption measurements.
13C CP-MAS, 29Si CP-MAS NMR, and FT-IR data exhibit
the successful incorporation of the organic species into the
solid materials. The existence of stable phenothiazine radical
cations in the materials has been clearly detected by UV/Vis
and EPR spectroscopy. In our ongoing project, we are work-
ing to increase the phenothiazine content in the pores. This
could lead to systems that exhibit charge transfer properties
or even electronic conductivities.
Experimental Section
General
All manipulations were carried out under an inert atmosphere of nitro-
gen and the solvents were dried by standard methods. Reagents were
purchased and used without further purification, unless otherwise noted.
While the hybrid materials 11-1, 11-2, and 11-3 show UV/
Vis data similar to the compound 10 series, the materials 12-
1 and 12-2 derived from the diphenothiazine precursor 9
behave differently. Oxidation of 12-1 and 12-2 by strongly
oxidizing SbCl5 furnished dark greenish products with an
absorption spectrum, which was different to those of the
monophenothiazine radical cations discussed above, indicat-
ing the presence of complex dicationic species.[16b,c]
Reagent grade reagents, catalysts, and solvents were purchased and used
without further purification. THF, diethyl ether,and methylene chloride
were dried and distilled according to standard procedures.[88] The pheno-
thiazine nitriles 2 and 3 were prepared according to literature proce-
dures.[30] Column chromatography: silica gel 60, mesh 70–230. TLC: silica
gel plates. 1H and 13C NMR spectra: CD2Cl2, CDCl3,and [D6]acetone
(locked to Me4Si).[89] The assignments of quaternary C, CH, CH2, and
CH3 have been made by DEPT spectra. Elemental analyses were carried
out in the Microanalytical Laboratories of the Organisch-Chemisches In-
stitut, Ruprecht-Karls-Universitꢀt, Heidelberg, Germany, in the Micro-
analytical Laboratories of the Institut fꢁr Pharmazeutische Chemie,
Heinrich-Heine-Universitꢀt, Dꢁsseldorf, Germany and in the Analytical
Laboratory of the Fachbereich Chemie, Technische Universitꢀt Kaiser-
slautern, Kaiserslautern, Germany.
EPR Spectroscopy
Electron paramagnetic resonance was used to additionally
confirm the existence of the stable phenothiazine radical
cations in the hybrid materials. The EPR spectrum of 12-2-
SbCl6 is shown in Figure 10. It reveals a g-value of 2.0053
Electrochemistry
Cyclic voltammetry experiments (EG&G potentiostatic instrumentation)
were performed under argon in dry and degassed CH2Cl2 at room tem-
perature and at scan rates of 100, 250, 500, and 1000 mVsꢀ1. The electro-
lyte was Bu4NPF6 (0.025m). The working electrode was a 1 mm platinum
disk, the counter-electrode was a platinum wire, and the reference elec-
trode was a Ag/AgCl electrode. The potentials were corrected to the in-
ternal standard of Fc/Fc+ in CH2Cl2 (E00/+1 =450 mV).[90]
Infrared spectra (KBr) were recorded using a Jasco FT-IR-6100 spec-
trometer. X-ray powder diffraction (XRD) patterns were obtained on a
Siemens D5005 diffractometer with CuKa radiation (30 kV, 30 mA). Ni-
trogen absorption and desorption isotherms were measured at 77 K on a
Quantachrome Autosorb 1 sorption analyzer after evacuation of the sam-
ples at 1208C overnight. The specific surface areas were calculated by the
Brunauer-Emmett-Teller (BET) equation in the low relative pressure in-
terval (<0.3) and the pore size distribution curves were analyzed with
the adsorption branch by the BJH method. 13C CP MAS and 29Si CP
MAS NMR were carried out on a Bruker DSX Avance spectrometer at
resonance frequencies of 100.6 and 79.5 MHz, respectively. UV/Vis dif-
fuse reflectance spectra were recorded on a Perkin–Elmer Lambda-18
with neat-MCM-41 as the background standard. Q-band CW ESR ex-
periments have been performed at 297 K on a Bruker EMX 10–40 spec-
trometer.
Figure 10. Q-band EPR spectrum of 12-2-SbCl6 at 2978C.
typical for phenothiazine radical cations. Since the EPR
signal was not well resolved, hyperfine coupling constants
and anisotropic g-tensors could not be determined. How-
ACHTUNGTRENNUNGever, the high symmetry of the EPR spectrum indicates that
the phenothiazine radicals are in an isotropic environment
in the hybrid material.
Synthesis
3-(10H-phenothiazine-10-yl)propionitrile (1): 10H-phenothiazine (10.0 g,
50.0 mmol) was suspended in acrylonitrile (75 mL, 1.13 mol) and cooled
to 08C. Triton B (5 mL) was added slowly and carefully to the well-strir-
red suspension, and then the reaction mixture was allowed to warm up to
room temperature. The solution was diluted with 1,4-dioxane (100 mL)
and stirred for 1 h at 1018C. After cooling to RT, the solution was
Conclusions
Novel hybrid organic/inorganic mesoporous silica materials
were synthesized by covalently anchoring phenothiazines on
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2011

T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
poured into water and a light brown solid precipitated. The solid was fil-
tered off and dried in vacuo. Recrystallization from acetone gave 1
(10.0 g, 80%) as colorless crystals. M.p.: 1568C (lit.: 156–1578C);[28]
1H NMR (CD2Cl2, 500 MHz): d=2.84 (t, J=7.0 Hz, 2H), 4.23 (t, J=
7.0 Hz, 2H), 6.87 (d, J=8.0 Hz, 2H), 6.99 (dt, tJ=7.5 Hz, dJ=1.0 Hz,
2H), 7.21 ppm (m, 4H); 13C NMR (CD2Cl2, 125 MHz): d=16.2 (CH2),
43.0 (CH2), 115.1 (CH), 117.2 (Cquat.), 123.0 (CH), 125.8 (Cquat.), 127.2
(CH), 127.4 (CH), 143.7 ppm (Cquat.); MS (EI+): m/z (%): 252.0 (73, M+),
124.5 (CH), 125.3 (CH), 125.4 (CH), 127.3 (CH), 127.8 (CH), 127.9
(CH), 128.2 (Cquat.), 128.7 (CH), 133.2 (Cquat.), 133.5 ppm (Cquat.); MS
(MALDI): calcd (%) for C37H43N3S2: 593.290; found: 593.162.
General procedure for the synthesis of the urea-linked triethoxysilylated
phenothiazines 7–9 (GP2): In a heat gun dried Schlenk vessel, the amine
hydrochlorides 4–6 (1 equiv) were suspended in dry dichloromethane
(0.04m) under nitrogen and triethylamine (2 equiv) was added. Upon stir-
ring for 30 min at RT, the suspension dissolved and the color changed
from orange to yellow. Then, 3-(triethoxysilyl)propylisocyanate (1 equiv)
was slowly added to the reaction mixture and the reaction was monitored
by TLC. After 2 h, the solvent was removed in vacuum. The crude prod-
uct was absorbed on celite and chromatographed on silica gel (hexanes/
ethyl acetate=2:3). The urea-linked triethoxysilylated phenothiazines 7–
9 were obtained as pure yellow solids.
212.0 (100, M+ꢀCH2CN), 198.0 (71, M+ꢀ
ACHTUNGTREN(NNUG CH2)2CN), 180.1 (71); elemen-
tal analysis: calcd (%) for C15H22N2S (252.2): C 71.40, H 4.79, N 11.10;
found: C 71.11, H 5.03, N 11.70.
General procedure for the reduction of phenothiazinyl substituted cyano
compounds 1–3 with lithium aluminium hydride (GP1): A solution of the
phenothiazinyl substituted cyano compounds 1–3 (1 equiv) in dry diethyl
ether was slowly added, through a dropping funnel, to a well-stirred mix-
ture of lithium aluminium hydride (2.3 equiv per CN bond) in dry diethyl
ether heated to 408C, over 20–30 min. The reaction mixture was stirred
at 408C for 16 h and was then cooled to 08C. Then, water (50 mL) and
diluted aqueous sodium hydroxide solution (20 wt%, 10 mL) were
added. The precipitate was filtered and the aqueous phase was washed
with small portions of diethyl ether. A small portion of conc. hydrochlo-
ric acid was added to the combined organic phases and the orange or red
precipitated products 4–6 were filtered and dried in vacuo.
(10H-phenothiazine-10-yl)propyl-3-(triethoxysilyl)propylurea (7): Yield:
87%. 1H NMR (CDCl3, 600 MHz): d=0.58 (t, J=8.4 Hz, 2H), 1.24 (t,
J=7 Hz, 9.0H), 1.52 (m, 2H), 2.00 (m, 2H), 3.02 (q, J=6 Hz, 2H), 3.30
(q, J=6 Hz, 2H), 3.82 (q, J=7.2 Hz, 6H), 3.99 (t, J=6 Hz, 2H), 4.46 (br,
1H), 4.90 (br, 1H), 6.93–6.99 (m, 4H), 7.19 ppm (m, 4H); 13C NMR
(CDCl3, 150.92 MHz): d=7.6 (CH2), 18.3 (CH3), 23.6 (CH2), 26.7 (CH2),
39.0 (CH2), 42.8 (CH2), 45.4 (CH2), 58.4 (CH2), 116.0 (CH), 122.9 (C),
125.4 (CH), 127.6 (CH), 127.8 (CH), 145.3 (C), 158.2 ppm (C=O); ele-
mental analysis: calcd (%) for C25H37N3O4SSi (503.73): C 59.61, H 7.40,
N 8.34; found: C 59.10, H 7.51, N 8.20.
3-(10H-phenothiazine-10-yl)propylamine hydrochloride (4):
1 (2.94 g,
11.7 mmol) was placed in a Soxhlet extractor and was extracted into dry
diethyl ether (500 mL) containing lithium aluminium hydride (1.02 g,
26.9 mmol). The extraction was performed at 408C for 3 d after which
the mixture was decomposed by means of addition of of water (1 mL)
and 20% aqueous sodium hydroxide solution (6 mL). The salts were re-
moved by filtration and the amine hydrochloride was isolated by the ad-
dition of of conc. hydrochloric acid (1 mL) into the ethereal filtrate.
Compound 4 was obtained as colorless needles (1.66 g, 48%). M.p.:
2278C; 1H NMR ([D6]DMSO, 500 MHz): d=2.00 (t, J=7.25 Hz, 2H),
2.87 (m, 2H), 3.99 (t, J=6.8 Hz, 2H), 6.97 (t, J=7.5 Hz, 2H), 7.08 (d, J=
8.0 Hz, 2H), 7.20 (m, 4H), 8.15 ppm (br, 3H); 13C NMR ([D6]DMSO,
125 MHz): d=24.5 (CH2), 36.5 (CH2), 43.6 (CH2), 116.0 (CH), 122.6
(CH), 123.9 (Cquat.), 127.1 (CH), 127.6 (CH), 144.5 ppm (Cquat.); MS
(FAB+): m/z (%): 257.2 (100, M+), 256.2 (70, M+ꢀH), 212.2 (23, M+
(10-hexyl-10H-phenothiazine-3-yl)methyl-3-(triethoxysilyl)propylurea
(8): Yield: 72%. H NMR (CDCl3, 400 MHz): d=0.60 (t, J=8.2 Hz, 2H),
0.86 (t, J=6.8 Hz, 3H), 1.21 (t, J=7 Hz, 9.0H), 1.27–1.31 (m, 4H), 1.41
1
(m, 2H), 1.60 (m, 2H), 1.77
ACHTUNGTRENNUNG
4.15 (m, 2H), 4.80 (br, 1H), 4.92 (br, 1H), 6.7–6.9AHCTUNGTRENNUNG
(m, 4H); 13C NMR (CDCl3, 150.92 MHz): d=7.9 (CH2), 14.3 (CH3), 18.7
(CH3), 22.9 (CH2), 24.0 (CH2), 27.0 (CH2), 31.8 (CH2), 43.3 (CH2), 44.1
(CH2), 47.8 (CH2), 58.8 (CH2), 115.7 (CH), 115.9(CH), 122.6 (CH), 125.0
(C), 126.9 (C), 127.6 (CH), 127.8 (CH), 133.9 (CH), 144.8 (C), 145.6 (C),
158.6 ppm (C=O); elemental analysis: calcd (%) for C29H45N3O4SSi
(559.84): C 62.22, H 8.10, N 7.51; found: C 61.60, H 7.98, N 7.20.
(10,10’-dihexyl-10H,10H’-3,3’-biphenothiazine-7-yl)methyl-3-(triethoxysi-
lyl)propylurea (9): Yield: 65%. 1H NMR (CDCl3, 400 MHz): d=0.62 (t,
J=8.0 Hz, 2H), 0.86 (t, J=7.0 Hz, 6H), 1.21 (t, J=7 Hz, 9H), 1.27–1.31
(m, 8H), 1.40 (m, 4H), 1.61 (m, 2H), 1.75 (m, 4H), 3.14 (m, 2H), 3.71–
3.90 (m, 10H), 4.14 (m, 2H), 5.41 (br, 1H), 5.25 (br, 1H), 6.65 (d, J=6,
1H), 6.71 (d, J=6, 1H), 6.81 (m, 4H), 7.01 (m, 2H), 7.12 (m, 1H), 7.19–
7.27 ppm (m, 4H); 13C NMR (CDCl3, 150.92 MHz): d=7.6 (CH2), 14.0
(CH3), 18.3 (CH3), 22.6 (CH2), 23.6 (CH2), 26.6 (CH2), 26.7 (CH2), 31.5
(CH2), 42.9 (CH2), 43.5 (CH2), 47.5 (CH2), 58.4 (CH2), 114.3 (CH), 115.2
(CH), 115.3 (CH), 115.6 (CH), 116.4 (CH), 122.3 (CH), 124.4 (C), 125.0
(CH), 125.1 (CH), 126.5 (CH), 126.6 (CH), 127.2 (CH), 127.4 (CH),
129.5 (CH), 129.9 (C), 133.7 (C), 133.8 (C), 134.5 (C), 143.7 (C), 144.2
(C), 158.7 ppm (C=O); elemental analysis: calcd (%) for C47H64N4O4S2Si
(841.25): C 67.10, H 7.67, N 6.66; found: C 66.60, H 7.98, N 6.40.
ꢀ
ACHTUNGTRENNUNG
for C15H16N2S·HCl (257.3+35.5): C 61.52, H 5.85, N 9.57; found: C 61.29,
H 5.93, N 9.33.
(10-Hexyl-10H-phenothiazine-3-yl)methylamine hydrochloride (5): Ac-
cording to GP1, the amine hydrochloride 5 (3.14 g, 89%) was isolated as
a light yellow solid. M.p.: 468C; IR (film): n˜ =2925, 1578, 1493, 1463,
1377, 1334, 1243, 1133, 887, 819, 746 cmꢀ1
;
1H NMR ([D6]DMSO,
500 MHz): d=0.81 (t, J=7.0 Hz, 3H), 1.22 (m, 4H), 1.36 (m, 2H), 1.65
(m, 2H), 3.86 (t, J=7.0 Hz, 2H), 3.90 (m, 2H), 6.94 (t, J=7.5 Hz, 1H),
7.02 (d, J=7.5 Hz, 2H), 7.14 (dd, J=1.5 Hz, J=7.5 Hz, 1H), 7.20 (t, J=
7.0 Hz, 1H), 7.29 (m, 2H), 8.33 ppm (br, 3H); 13C NMR ([D6]DMSO,
125 MHz): d=13.8 (CH3), 22.0 (CH2), 25.7 (CH2), 26.1 (CH2), 30.8
(CH2), 41.3 (CH2), 46.4 (CH2), 115.6 (CH), 115.9 (CH), 122.6 (CH), 123.0
(Cquat.), 123.6 (Cquat.), 127.1 (CH), 127.7 (CH), 127.8 (CH), 128.0 (Cquat.),
128.5 (CH), 144.5 (Cquat.), 144.8 ppm (Cquat.); MS (FAB+): m/z (%): 312.3
(73, M+), 296.0 (100, M+ꢀNH2), 241.2 (8, M+ꢀC5H11), 227.1 (11, M+
ꢀC6H13), 212.1 (17), 211.1 (12, M+ꢀNH2ꢀC6H13); elemental analysis:
calcd (%) for C19H24N2S·HCl (312.3+36.5): C 65.40, H 7.22, N 8.03;
found: C 65.20, H 7.18, N 7.96.
General procedure for the synthesis of the hybrid materials: In a typical
synthetic procedure, an aqueous solution of CTAB was mixed with ethyl-
amine under stirring. Then a solution of the precursor 7, 8, or 9 in metha-
nol and an appropriate amount of TEOS were added dropwise. The com-
position of the mixture in molar ratio was 1.0:x:0.14:2.4:2.0:100 SiO2/pre-
cursor/CTAB/EtNH2/methanol/H2O (10-1: x=0.025, 10-2: x=0.049, 10-3:
x=0.075, 11-1: x=0.022, M2-2: x=0.037, 11-3: x=0.052, 12-1: x=0.026,
M3-2: x=0.036). The reaction mixture was stirred for a further 24 h at
RT before being heated to 1008C for 24 h. The product was recovered by
filtration, washed thoroughly with distilled water until pH 7 was ach-
ieved. The colorless powdery material was dried in vacuum at 508C. The
surfactant (CTAB) was extracted by twofold stirring of the as-synthesized
hybrid material (1.0 g) in ethanol (80 mL) and an aqueous solution of
HCl (36%, 1.0 mL) under reflux for 8 h. The resulting solid was then fil-
tered, washed with ethanol and CH2Cl2 and vacuum dried at 508C. Ele-
mental analyses: 10-1: C 11.68, H 2.05, N 1.37, corresponding to a loading
of 0.33 mmolgꢀ1; 10-2: C 16.53, H 2.83, N 2.26, corresponding to a load-
ing of 0.54 mmolgꢀ1; 10-3: C 20.33, H 2.81, N 3.25, corresponding to a
loading of 0.77 mmolgꢀ1; 11-1: C 10.16, H 2.60, N 1.10, corresponding to
(10,10ꢁ-Dihexyl-10H,10ꢁH-3ꢁ,7-biphenothiazine-3-yl)methylamine hydro-
chloride (6): According to GP1 the amine hydrochloride 6 (689 mg,
92%) was isolated as a yellow solid. M.p.: 1528C; UV/Vis (CH2Cl2): lmax
(e): 270 (88500), 284 (73600), 325 nm (32700); IR (KBr): n˜ =2926, 2854,
1603, 1578,1460, 1415, 1375, 1333, 1245, 1193, 1106, 1054, 873, 807,746,
613 cmꢀ1 1H NMR ([D6]DMSO, 500 MHz): d=0.81 (m, 6H), 1.22–1.36
;
(m, 12H), 1.66 (m, 4H), 2.49 (s, 2H) 3.85 (m, 6H), 6.92–7,12 (m, 4H),
7.14–7.41 (m, 8H), 8.28 ppm (s, 2H); 13C NMR ([D6]DMSO, 125 MHz):
d=14.0 (CH3), 22.2 (CH2), 26.4 (CH2), 31.1 (CH2), 46.6 (CH2), 47.8
(CH2), 115.7 (CH), 115.9 (CH), 116.2 (CH), 116.3 (CH), 122.6
(CH),123.3 (Cquat.), 123.4 (Cquat.), 123.7 (Cquat.), 124.3 (Cquat.), 124.5 (CH),
2012
www.chemasianj.org
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2010, 5, 2001 – 2015

In Situ Syntheses of Mesoporous Hybrid Materials
a loading of 0.26 mmolgꢀ1; 11-2: C 17.79, H 3.23, N 1.68, corresponding
to a loading of 0.40 mmolgꢀ1; 11-3: C 19.81, H 3.59, N 2.25, correspond-
ing to a loading of 0.54 mmolgꢀ1; 12-1: C 15.24, H 2.40, N 1.54, corre-
sponding to a loading of 0.28 mmolgꢀ1; 12-2: C 19.79, H 2.97, N 1.93, cor-
[9] S. A. Song, G. R. Lee, S. H. Lim, H. M. Kim, S. B. Park, S. M. Yang,
Repub. Korean Kongkae Taeho Kongbo 2008, KR 2008004237.
[10] T. Itoh, K. Yano, T. Kajino, S. Itoh, Y. Shibata, H. Mino, R. Miya-
moto, Y. Inada, S. Iwai, Y. Fukushima, J. Phys. Chem. B 2004, 108,
13683–13687.
responding to a loading of 0.34 mmolgꢀ1
.
[11] a) C.-H. Lee, T.-S. Lin, C.-Y. Mou, J. Phys. Chem. B 2003, 107,
2543–2551; b) C.-H. Lee, J. Lang, C.-W. Yen , P.-C. Shih, T.-S. Lin,
C.-Y. Mou, J. Phys. Chem. B 2005, 109, 12277–12286.
[12] a) K. T. Ranjit, L. Kevan, J. Phys. Chem. B 2003, 107, 2610; b) R. M.
Krishna, L. Kevan, Phys. Chem. Chem. Phys. 2001, 3, 5348–5353.
[13] K. Toriyama, M. Okazaki, Phys. Chem. Chem. Phys. 1999, 1, 2607–
2612.
Generation of radical cations: In a typical process, the hybrid material
(0.10 g) was suspended in dry dichloromethane (5 mL). The solution was
stirred at RT and a molar excess of NOBF4 or SbCl5 was added. The
color of the samples immediately changed. The solids were filtered off,
extracted with dichloromethane, and dried under vacuum.
[14] a) M. Sainsbury in Roddꢀs Chem. Carbon Compd., Vol. 4, 2nd ed.,
(Ed.: M. Sainsbury), Elsevier, Amsterdam, 1998, p. 575; b) M. Sains-
bury in Comprehensive Heterocyclic Chemistry, Vol. 3, (Eds.: A. R.
Katritzky, C. W. Rees), Pergamon Press, Oxford, 1984, p. 995;
c) H. J. Shine, D. R. Thompson, C. J. Veneziani, Heterocycl. Chem.
1967, 4, 517–527; d) L. A. Tinker, A. J. Bard, J. Am. Chem. Soc.
1979, 101, 2316–2319; e) B. Paduszek, M. K. Kalinowski, Electro-
chim. Acta 1983, 28, 639–642.
Acknowledgements
This project was supported by the DFG Schwerpunktprogramm SPP
1181 (Nanoscaled Inorganic Materials by Molecular Design: New Materi-
als for Advanced Technologies; NANOMAT).
[15] a) F. Mietzsch, Angew. Chem. 1954, 66, 363–371; b) M. Ionescu, H.
Mantsch, Adv. Heterocycl. Chem. 1967, 8, 83–113; c) C. Bodea, I.
Silberg, Adv. Heterocycl. Chem. 1968, 9, 321–460; d) L. Valzelli, S.
Garattini in Prinicples of Psychopharmacology (Ed.: W. G. Clark),
Academic Press, 1970, pp. 255–258; e) C. O. Okafor, Heterocycles
1977, 7, 391–427; f) Z. Eckstein, T. Urbanski, Adv. Heterocycl.
Chem. 1979, 23, 1–53; g) J. Szabꢃ, Chem. Heterocycl. Compd. 1979,
15, 291–308; h) W. J. Albery, A. W. Foulds, K. J. Hall, A. R. Hill-
man, R. G. Edgell, A. F. Orchard, Nature 1979, 282, 793–797.
[16] a) H. Oka, J. Mater. Chem. 2008, 18, 1927–1934; b) T. Okamoto, M.
Kuratsu, M. Kozaki, K. Hirotsu, A. Ichimura, T. Matsushita, K.
Okada, Org. Lett. 2004, 6, 3493–3496; c) D. Sun, S. V. Rosokha,
J. K. Kochi, J. Am. Chem. Soc. 2004, 126, 1388–1401; d) J. K. Kochi,
R. Rathore, P. Le Maguꢄres, J. Org. Chem. 2000, 65, 6826–6836;
e) T. Nishinaga, R. Inoue, A. Matsuura, K. Komatsu, Org. Lett.
2002, 4, 1435–1438; f) D. Pan, D. L. Philips, J. Phys. Chem. A 1999,
103, 4737–4743.
[17] a) R. Duesing, G. Tapolsky, T. J. Meyer, J. Am. Chem. Soc. 1990,
112, 5378–5379; b) W. E. Jones Jr. , P. Chen, T. J. Meyer, J. Am.
Chem. Soc. 1992, 114, 387–388; c) A. M. Brun, A. Harriman, V.
Heitz, J.-P. Sauvage, J. Am. Chem. Soc. 1991, 113, 8657–8663;
d) H. D. Burrows, T. J. Kemp, M. J. Welburn, J. Chem. Soc. Perkin
Trans. 2 1973, 969–974; e) J.-P. Collin, S. Guillerez, J.-P. Sauvage, J.
Chem. Soc. Chem. Commun. 1989, 776–778; f) J. Daub, R. Engl, J.
Kurzawa, S. E. Miller, S. Schneider, A. Stockmann, M. R. Wasielew-
ski, J. Phys. Chem. A 2001, 105, 5655–5665.
[18] a) R. C. Wheland, J. L. Gillson, J. Am. Chem. Soc. 1976, 98, 3916–
3925; b) P. Berges, J. Kudnig, G. Klar, E. Sanchez-Martinez, R.
Diaz-Calleja, Synth. Met. 1992, 46, 207–219; c) A. Knorr, J. Daub,
Angew. Chem. 1995, 107, 2925–2927; Angew. Chem. Int. Ed. Engl.
1995, 34, 2664–2666; d) H. Spreitzer, M. Scholz, G. Gescheidt, J.
Daub, Liebigs Ann. 1996, 2069–2077; e) H. Spreitzer, J. Daub,
Chem. Eur. J. 1996, 2, 1150–1158.
[19] a) Ntera Limited, Ire. , Eur. Pat. Appl., 2004, 13 EP 1443090A1
20040804; b) Mitsubishi Electric Corp., Japan, Jpn. Kokai Tokkyo
Koho 1985, 4JP 60115681A2 19850622.
[20] a) X. Kong, A. P. Kulkarni, S. A. Jenekhe, Macromolecules 2003, 36,
8992–8999; b) R. Y. Lai, X. Kong, S. A. Jenekhe, A. J. Bard, J. Am.
Chem. Soc. 2003, 125, 12631–12639; c) S. A. Jenekhe, L. Lu, M. M.
Alam, Macromolecules 2001, 34, 7315–7324; d) R. Y. Lai, E. F. Fab-
rizio, L. Lu, S. A. Jenekhe, A. J. Bard, J. Am. Chem. Soc. 2001, 123,
9112–9118; e) A. Higuchi, H. Inada, T. Kobata, Y. Shiraota, Adv.
Mater. 1991, 3, 549–550.
[21] a) L. S. Park, Y. S. Han, D. S. Kim, J. S. Hwang, Mol. Cryst. Liq.
Cryst. Sci. Technol. Sect. A 2001, 371, 309–312; b) D.-H. Hwang, S.-
K. Kim, M.-J. Park, J.-H. Lee, B.-W. Koo, I.-N. Kang, S.-H. Kim, T.
Zyung, Chem. Mater. 2004, 16, 1298–1303.
[1] 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.
[2] a) G. J. de A. A. Soler-Illia, C. Sanchez, B. Lebeau, J. Patarin,
Chem. Rev. 2002, 102, 4093–4138; b) M. Widenmeyer, R. Anwan-
der, Chem. Mater. 2002, 14, 1827–1831.
[3] a) H.-P. Lin, C.-Y. Mou, Acc. Chem. Res. 2002, 35, 927–935; b) B.
Hatton, K. Landskron, W. Whitnall, D. Perovic, G. A. Ozin, Acc.
Chem. Res. 2005, 38, 305–312.
[4] a) R. Anwander, Chem. Mater. 2001, 13, 4419–4438; b) J. Morell, G.
Wolter, M. Frçba, Chem. Mater. 2005, 17, 804–808; c) C. Yoshina-
Ishii, T. Asefa, N. Coombs, M. J. MacLachlan, G. A. Ozin, Chem.
Commun. 1999, 2539–2540; d) S. Guan, S. Inagaki, T. Ohsuna, O.
Terasaki, J. Am. Chem. Soc. 2000, 122, 5660–5661; e) S. Inagaki, S.
Guan, Y. Fukushima, T. Ohsuna, O. Terasaki, J. Am. Chem. Soc.
1999, 121, 9611–9614; f) B. J. Melde, B. T. Holland, C. F. Blanford,
A. Stein, Chem. Mater. 1999, 11, 3302–3308; g) T. Asefa, M. J. Ma-
cLachlan, N. Coombs, G. A. Ozin, Nature 1999, 402, 867–871; h) J.
Sauer, F. Marlow, B. Spliethoff, F. Schꢁth, Chem. Mater. 2002, 14,
217–224; i) T. Abe, Y. Tachibana, M. Iwamoto, Chem. Commun.
1995, 1617–1618; j) H. van Bekkum, K. R. Kloetstra, Stud. Surf. Sci.
Catal. 1998, 117, 171–182; k) V. R. Choudhary, S. K. Jana, B. P.
Kiran, J. Catal. 2000, 192, 257–261; l) M. Iwamoto, T. Abe, Y. Tachi-
bana, J. Mol. Catal. A 2000, 155, 143–153; m) A. Wingen, N. Anas-
tasievic, A. Hollnagel, D. Werner, F. Schꢁth, J. Catal. 2000, 193,
248–254; n) M. Frçba, R. Kçhn, G. Bouffaud, O. Richard, G. van
Tendeloo, Chem. Mater. 1999, 11, 2858–2865; o) A. Zecchina, D.
Scarano, G. Spoto, S. Bordiga, C. Lamberti, G. Bellussi, Stud. Surf.
Sci. Catal. 1998, 117, 343–350; p) F. Hoffmann, M. Cornelius, J.
Morell, M. Frçba, Angew. Chem. 2006, 118, 3290–3328; Angew.
Chem. Int. Ed. 2006, 45, 3216–3251; q) A. Stein, B. J. Melde, R. C.
Schroden, Adv. Mater. 2000, 12, 1403–1419.
[5] a) D. E. de Vos, M. Dams, B. F. Sels, P. A. Jacobs, Chem. Rev. 2002,
102, 3615–3640; b) A. P. Wight, M. E. Davis, Chem. Rev. 2002, 102,
3589–3614; c) C. E. Song, S. Lee, Chem. Rev. 2002, 102, 3495–3524;
d) A. Sayari, S. Hamoudi, Chem. Mater. 2001, 13, 3151–3168.
[6] a) R. Plass, S. Pelet, J. Krꢁger, M. Grꢀtzel, U. Bach, J. Phys. Chem.
B 2002, 106, 7578–7580; b) X. Gao, S. Nie, J. Phys. Chem. B 2003,
107, 11575–11578.
[7] F. J. Brieler, P. Grundmann, M. Frçba, L. Chen, P. J. Klar, W. Heim-
brodt, H.-A. Krug von Nidda, T. Kurz, A. Loidl, J. Am. Chem. Soc.
2004, 126, 797–807.
[8] a) F. J. Brieler, P. Grundmann, M. Frçba, L. Chen, P. J. Klar, W.
Heimbrodt, H.-A. Krug von Nidda, T. Kurz, A. Loidl, Chem. Mater.
2005, 17, 795–803; b) A.-H. Lu, W.-C. Li, A. Kiefer, W. Schmidt, E.
Bill, G. Fink, F. Schꢁth, J. Am. Chem. Soc. 2004, 126, 8616–8617.
[22] Y. S. Han, S. D. Kim, L. S. Park, D. U. Kim, Y. Kwon, J. Polym. Sci.
Part A 2003, 41, 2502–2511.
Chem. Asian J. 2010, 5, 2001 – 2015
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
2013

T. J. J. Mꢁller, W. R. Thiel et al.
FULL PAPERS
[23] a) G. R. Hutchison, M. A. Ratner, T. J. Marks, J. Am. Chem. Soc.
2005, 127, 2339–2350; b) B. Rybtchinski, L. E. Sinks, M. R. Wasie-
lewski, J. Am. Chem. Soc. 2006, 128, 649–657.
[24] N. Nambu, S. Sakurai, T. Nagai, Chem. Pharm. Bull. 1974, 22, 1405–
1407.
[53] E. P. Barrett, L. G. Joyner, P. P. Halenda, J. Am. Chem. Soc. 1951,
73, 373–380.
[54] K. S. W. Sing, D. H. Everett, R. A. W. Haul, L. Moscou, R. A. Pier-
otti, J. Rouquerol, T. Siemieniewska, Pure Appl. Chem. 1985, 57,
603–619.
[55] P. I. Ravikovitch, S. C. Odomhnaill, A. V. Neimark, F. Schꢁth, K. K.
Unger, Langmuir 1995, 11, 4765–4772.
[56] F. Rojas, I. Kornhauser, C. Felipe, J. M. Esparza, S. Cordero, A.
Dominguez, J. L. Riccardo, Phys. Chem. Chem. Phys. 2002, 4, 2346–
2355.
[25] B. Xiang, L. Kevan, Langmuir 1994, 10, 2688–2693.
[26] a) K. C. Khulbe, R. S. Mann, J. Catal. 1988, 112, 579–584; b) R. M.
Krishna, V. Kurshev, L. Kevan, Phys. Chem. Chem. Phys. 1999, 1,
2833–2839; c) Z. Luan, J. Y. Bae, L. Kevan, Chem. Mater. 2000, 12,
3202–3207; d) Z. Luan, L. Kevan, Stud. Surf. Sci. Catal. 2001, 135,
3871–3877; e) Z. Luan, J. Y. Bae, L. Kevan, Microporous Mesopo-
rous Mater. 2001, 48, 189–194.
[57] A. Corma, Q. B. Kan, M. T. Navarro, J. Perez-Pariente, F. Rey,
Chem. Mater. 1997, 9, 2123–2126.
[58] A. V. Neimark, P. I. Ravikovitch, M. Grun, F. Schꢁth, K. K. Unger,
J. Colloid Interface Sci. 1998, 207, 159–169.
[59] a) M. H. Lim, C. F. Blanford, A. Stein, Chem. Mater. 1998, 10, 467–
470; b) S. L. Burkett, S. D. Sims, S. Mann, Chem. Commun. 1996,
1367–1368; c) C. E. Fowler, S. L. Burkett, S. Mann, Chem.
Commun. 1997, 1769–1770.
[27] a) A. W. Franz, Z. Zhou, R. Turdean, A. Wagener, B. Sarkar, M.
Hartmann, S. Ernst, W. R. Thiel, T. J. J. Mꢁller, Eur. J. Org. Chem.
2009, 3895–3905; b) Z. Zhou, A. W. Franz, M. Hartmann, A. Sei-
fert, T. J. J. Mꢁller, W. R. Thiel, Chem. Mater. 2008, 20, 4986–4992.
[28] E. F. Godefroi, E. L. Wittle, J. Org. Chem. 1956, 21, 1163–1168.
[29] T. Schareina, A. Zapf, M. Beller, Chem. Commun. 2004, 1388–1389.
[30] A. W. Franz, L. N. Popa, T. J. J. Mꢁller, Tetrahedron Lett. 2008, 49,
3300–3303.
[60] C. E. Fowler, S. Mann, B. Lebeau, Chem. Commun. 1998, 1825–
1826.
[61] A. Corma, Chem. Rev. 1997, 97, 2373–2419.
[62] R. Richer, L. Mercier, Chem. Mater. 2001, 13, 2999–3008.
[63] S. M. Gruner, J. Phys. Chem. 1989, 93, 7562–7570.
[64] C. J. Brinker, G. W. Scherer, Sol-Gel Science, Academic Press,
Boston, 1990.
[65] J. M. Thomas, O. Terasaki, P. L. Gai, W. Z. Zhou, J. Gonzalez-
Calbet, Acc. Chem. Res. 2001, 34, 583–594.
[66] S. Huh, J. W. Wiench, J. C. Yoo, M. Pruski, V. S. Y. Lin, Chem.
Mater. 2003, 15, 4247–4256.
[31] S. van der Laan, B. L. Feringa, R. M. Kellogg, J. van Esch, Langmuir
2002, 18, 7136–7140.
[32] J. J. E. Moreau, B. P. Pichon, C. Bied, M. W. C. Man, J. Mater. Chem.
2005, 15, 3929–3936.
[33] F. P. Schmidtchen, M. Berger, Chem. Rev. 1997, 97, 1609–1646.
[34] E. J. Cho, J. W. Moon, S. W. Ko, J. Y. Lee, S. K. Kim, J. Yoon, K. C.
Nam, J. Am. Chem. Soc. 2003, 125, 12376–12377.
[35] a) N. Hovnanian, S. Cerneaux, P. Dieudonne, J. Sol-Gel Sci. Technol.
2004, 31, 353–358; b) Y. Luo, P. Yang, J. Lin, Microporous Mesopo-
rous Mater. 2008, 111, 194–199; c) M. ꢅlvaro, M. Benitez, D. Das,
B. Ferrer, H. Garcꢆa, Chem. Mater. 2004, 16, 2222–2228; d) M. Beni-
tez, D. Das, R. Ferreira, U. Pischel, H. Garcꢆa, Chem. Mater. 2006,
18, 5597–5603.
[36] L. Yang, J.-K. Feng, A.-M. Ren, J. Org. Chem. 2005, 70, 5987–5996.
[37] M. Jia, A. Seifert, M. Berger, H. Giegengack, S. Schulze, W. R.
Thiel, Chem. Mater. 2004, 16, 877–882.
[38] K. Moller, T. Bein, R. X. Fischer, Chem. Mater. 1999, 11, 665–673.
[39] M. T. Anderson, J. E. Martin, J. G. Odinek, P. P. Newcomer, Chem.
Mater. 1998, 10, 1490–1500.
[40] Q. Huo, D. I. Margolese, G. D. Stucky, Chem. Mater. 1996, 8, 1147–
1160.
[41] B. Marler, U. Oberhagemann, S. Vortmann, H. Gies, Microporous
Mater. 1996, 6, 375–383.
[42] M. Kruk, M. Jaroniec, A. Sayari, J. Phys. Chem. B 1999, 103, 4590–
4598.
[43] M. H. Lim, C. F. Blanford, A. Stein, J. Am. Chem. Soc. 1997, 119,
4090–4091.
[44] J. C. Vartuli, K. D. Schmitt, C. T. Kresge, W. J. Roth, M. E. Leono-
wicz, S. B. McCullen, S. D. Hellring, J. S. Beck, J. L. Schlenker,
Chem. Mater. 1994, 6, 2317–2326.
[45] Q. Huo, D. I. Margolese, U. Ciesla, D. G. Demuth, P. Feng, T. E.
Gier, P. Sieger, A. Firouzi, B. F. Chmelka, Chem. Mater. 1994, 6,
1176–1191.
[67] S. Huh, J. W. Wiench, B. G. Trewyn, S. Song, M. Pruski, V. S. Y. Lin,
Chem. Commun. 2003, 2364–2365.
[68] N. B. Colthup in An Introduction to Infrared and Raman Spectrosco-
py (Eds.: L. H. Daly, S. E. Wiberley), Academic Press, Boston, 1990.
[69] L. P. Kuhn, J. Am. Chem. Soc. 1952, 74, 2492–2499.
[70] J. Jadzyn, M. Stockhausen, B. Zywucki, J. Phys. Chem. 1987, 91,
754–757.
[71] X. S. Zhao, G. Q. Lu, A. K. Whittaker, G. J. Millar, H. Y. Zhu, J.
Phys. Chem. B 1997, 101, 6525–6531.
[72] M. Frçba, P. Behrens, J. Wong, G. Engelhardt, C. Haggenmꢁller, G.
Vandegoor, M. Rowen, T. Tanaka, W. Schwieger in Advances in
Porous Materials, (Eds.: S. Komarneni, D. M. Smith, J. S. Beck), Ma-
terials Research Soc., Pittsburgh, 1995, pp. 99–104.
[73] D. W. Sindorf, G. E. Maciel, J. Am. Chem. Soc. 1981, 103, 4263–
4265.
[74] S. M. De Paul, J. W. Zwanziger, R. Ulrich, U. Wiesner, H. W. Spiess,
J. Am. Chem. Soc. 1999, 121, 5727–5736.
[75] S. Ek, E. I. Iiskola, L. Niinistç, J. Vaittinen, T. T. Pakkanen, A.
Root, J. Phys. Chem. A 2004, 108, 11454–11463.
[76] D. Fattakhova Rohlfing, J. Rathousky, Y. Rohlfing, O. Bartels, M.
Wark, Langmuir 2005, 21, 11320–11329.
[77] A. J. Bard, L. R. Faulkner, Electrochemical Methods Fundamentals
and Applications, Wiley, New York, 2001.
[78] R. W. Murray, Chemically Modified Electrodes in Electroanalytical
Chemistry, A Series of Advances, Vol. 13, New York, 1984.
[79] Y. Guo, A. Mylonakis, Z. Zhang, G. Yang, P. I. Lelkes, S. Che, Q.
Lu, Y. Wei, Chem. Eur. J. 2008, 14, 2909–2917.
[46] R. Huq, L. Mercier, P. J. Kooyman, Chem. Mater. 2001, 13, 4512–
4519.
[47] M. C. Holmes, Curr. Opin. Colloid Interface Sci. 1998, 3, 485–492.
[48] U. Henriksson, E. S. Blackmore, G. J. T. Tiddy, O. Soederman, J.
Phys. Chem. 1992, 96, 3894–3902.
[49] Z. Zhang, Y. Han, F.-S. Xiao, S. Qiu, L. Zhu, R. Wang, Y. Yu, Z.
Zhang, B. Zou, Y. Wang, H. Sun, D. Zhao, Y. Wei, J. Am. Chem.
Soc. 2001, 123, 5014–5021.
[80] A. Domꢇnech, M. Alvaro, B. Ferrer, H. Garcia, J. Phys. Chem. B
2003, 107, 12781–12788.
[81] N. C. Maiti, S. Mazumdar, N. Periasamy, J. Phys. Chem. B 1998, 102,
1528–1538.
[82] G. R. Hutchison, M. A. Ratner, T. J. Marks, J. Am. Chem. Soc. 2005,
127, 16866–16881.
[50] R. K. Iler, The Chemistry of Silica, Wiley, New York, 1971.
[51] X. Liu, B. Tian, C. Yu, F. Gao, S. Xie, B. Tu, R. Che, L.-M. Peng, D.
Zhao, Angew. Chem. 2002, 114, 4032–4034; Angew. Chem. Int. Ed.
2002, 41, 3876–3878.
[52] A. Monnier, F. Schꢁth, Q. Huo, D. Kumar, D. Margolese, R. S. Max-
well, G. D. Stucky, M. Krishnamurty, P. Petroff, A. Firouzi, M. Jan-
icke, B. F. Chmelka, Science 1993, 261, 1299–1303.
[83] P. A. Leermakers, H. T. Thomas, L. D. Weis, F. C. James, J. Am.
Chem. Soc. 1966, 88, 5075–5083.
[84] E. H. A. Beckers, S. C. J. Meskers, A. P. H. J. Schenning, Z. Chen, F.
Wꢁrthner, P. Marsal, D. Beljonne, J. Cornil, R. A. J. Janssen, J. Am.
Chem. Soc. 2006, 128, 649–657.
[85] M. Sailer, A. W. Franz, T. J. J. Mꢁller, Chem. Eur. J. 2008, 14, 2602–
2614.
2014
www.chemasianj.org
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Asian J. 2010, 5, 2001 – 2015

In Situ Syntheses of Mesoporous Hybrid Materials
[86] a) P. L. Maguꢄres, S. V. Lindeman, J. K. Kochi, J. Chem. Soc. Perkin
Trans. 2 2001, 1180–1185; b) B. Badger, B. Brocklehurst, Nature
1968, 219, 263–263.
[89] M. Hesse, H. Meier, B. Zeeh, Spektroskopische Methoden in der Or-
ganischen Chemie, Georg Thieme Verlag, Stuttgart, 1991, pp. 69.
[90] P. Zanello in Ferrocenes (Eds.: A. Togni, T. Hayashi), VCH, Wein-
heim, 1995, pp. 317.
[87] A. Ortiz, I. Poyato, J. I. Fernandez-Alonso, J. Pharm. Sci. 1983, 72,
50–55.
Received: March 31, 2010
Published online: August 2, 2010
[88] Organikum, 21st ed. (Eds.: H. G. O. Becker, R. Beckert, G.
Domschke, E. Fanghꢀnel, W. D. Habicher, P. Metz, D. Pavel, K.
Schwetlick), Wiley-VCH, Weinheim, 2001.
Chem. Asian J. 2010, 5, 2001 – 2015
ꢂ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemasianj.org
2015