Synthesis and crystal structures of axially substituted titaniumphthalocyanines and preparation of PcTi@SBA-15 and PcTi&TiO x@SBA-15 materials

Article abstract of DOI:10.1002/zaac.200801289

Four axially substituted titanium(IV)phthalocyanines of formula trans-[PcTi(OSiPh₃)₂], [PcTiJ{(NH)₂C ₆H₄}], [PcTi(η²-S₂)], and [PcTi=S] were prepared starting from the reactive s

Full text of DOI:10.1002/zaac.200801289

ARTICLE
DOI: 10.1002/zaac.200801289
Synthesis and Crystal Structures of Axially Substituted
Titaniumphthalocyanines and Preparation of PcTi@SBA-15 and
PcTi&TiOx@SBA-15 Materials
Wael Darwish,[a] Sabine Schlecht,*[b] Andreas Schaper,[c] Michael Fröba,[d] Klaus Harms,[a]
Werner Massa,[a] Jörg Sundermeyer*[a]
Dedicated to Professor Bernt Krebs on the Occasion of His 70th Birthday
Keywords: Titanium; Phthalocyanines; Structure elucidation; SBA-15; Mesoporous materials
˚
Abstract. Four axially substituted titanium(IV)phthalocyanines of
formula trans-[PcTi(OSiPh3)2], [PcTi{(NH)2C6H4}], [PcTi(η2-S2)],
13.1495(9) A, Ͱ ϭ 114.124(5)°, β ϭ 99.452(6)°, γ ϭ 96.174(6)°, and
Z ϭ 1. [PcTiS2] crystallizes from chlorobenzene in the monoclinic
˚
˚
and [PcTiϭS] were prepared starting from the reactive species space group P21/n with a ϭ 13.114(3) A, b ϭ 9.752(2) A, c ϭ
˚
N,NЈ-di-4-tolylureato(phthalocyaninato)titanium(IV). The pre-
pared compounds were characterized by using UV/Vis-spec-
troscopy, FT-IR and raman spectroscopy, TGA, elemental
analysis and MALDI-TOF measurements. The compound trans-
[PcTi(OSiPh3)2] crystallizes from chlorobenzene in the triclinic
20.975(5) A, β ϭ 100.46(2), and Z ϭ 4. The crystal structures of
both compounds are discussed. The reactive ureato complex could
also successfully be anchored onto SBA-15 and TiOx@SBA-15
materials using the apical ureato ligand as a good leaving group
for the reaction with the silanol groups of the host material.
˚
˚
¯
space group P1 with a ϭ 10.4160(8) A, b ϭ 11.2160(8) A, c ϭ
however no complete characterization of the sulfido and
selenido complex was presented [5]. Titanium porphyrins
such as [(TTP)TiϭS] or [(TTP)TiϭSe] (TTP ϭ tetratolyl-
porphyrine) have been prepared by atom transfer reaction
of [(TTP)Ti(η2-PhCϵCPh)] with Ph3PϭS or Ph3PϭSe
[6]. The dichalcogenido species [(TTP)Ti(η2-S2)] and
[(TTP)Ti(η2-Se2)] are reported in the literature as well [7].
Segura et al. [8] prepared TiϪSBA-15 by heating solu-
tions of [TiO(acac)2] with SBA-15 and the titanyl function
was found to covalently bind to most of the OH groups on
SBA-15 surface. Landau et al. [9] achieved TiO2 loading of
(30Ϫ80 %) inside the pores of SBA-15 silica by chemical
solution decomposition (CSD) or internal hydrolysis (IH)
of [Ti(OnBu)4] as titanium precursor. Both methods yielded
composites with high TiO2 crystalinity (anatase). Pera-
thoner et al. [10] reported that in case of titanium loadings
up to 12Ϫ13 wt%, the XRD patterns are in agreement with
the model of a guest phase layer uniformly covering the
inner part of SBA-15 walls, while higher titanium loading
leads to patterns like that of separate TiO2 nanoparticles.
Calleja et al. [11] studied the grafting of titanium
(1Ϫ3 wt%) in SBA-15 using titanocene dichloride
[Cp2TiCl2]. The UV/Vis spectrum of the prepared TiϪSBA-
15 showed the presence of titanium isolated species tetra-
hedrally coordinated and the absence of bulk TiO2 phase.
Peng Wu et al. [12 a] studied the preparation of TiϪSBA-15
by titanation of pure SBA-15 with [Ti(OnBu)4] in glycerol
containing quaternary ammonium hydroxide. Srivastava et
Introduction
Titanium phthalocyanines (Pc) have a wide range of
interesting properties and found a lot of applications in
many industrially fields such as the manufacture of electro-
photographic and electrochromic materials [1] or NLO ma-
terials and molecular sieves pigments [2]. Synthesis of new
axially substituted TiPcs by reaction of [PcTiCl2] with
oxalic acid, Ph3SiOH, H2O2, etc [3] or reaction of [PcTiO]
with strongly chelating oxygen or sulfur donor ligands [4]
is established in the literature. Also, chalcogenido-TiPcs of
formula [R4PcTi ϭ X], where X ϭ O, S, Se were mentioned
in a patent as useful materials in charge-generating layers,
* Prof. Dr. S. Schlecht
Fax: ϩ49-30-838-53310
E-Mail: schlecht@chemie.fu-berlin.de
* Prof. Dr. J. Sundermeyer
Fax: ϩ49-6421-28-25711
E-Mail: jsu@staff.uni-marburg.de
[a] Fachbereich Chemie der Philipps-Universität
Hans-Meerwein-Straße
35032 Marburg, Germany
[b] Institut für Chemie und Biochemie der Freien Universität
Fabeckstraße 34Ϫ36
14195 Berlin, Germany
[c] Wissenschaftliches Zentrum für Materialwissenschaften
Philipps-Universität
Marburg, Germany
[d] Institut für Anorganische und Angewandte Chemie
Universität Hamburg
Hamburg, Germany
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ARTICLE
al. [13] functionalized TiϪSBA-15 to TiϪSBA-15ϪprϪCl mass and IR spectroscopic measurements. The UV/Vis
and TiϪSBA-15ϪprϪNH2 using the corresponding iso- spectrum of 2 in chloronaphthalene (Figure 1) shows a split
propyl titanate. Afterwards adenine was grafted in these (Q0.0) absorption band at λmax ϭ 741 nm and 698 nm.
active sites and an active catalyst for the synthesis of cyclic Another allowed πϪπ* transition at λmax ϭ 356.5 nm
carbonates was obtained.
(B-band) is observed. The shoulders at λmax ϭ 663.5 nm
In many applications, the phthalocyanine compounds and 630.0 nm are observed and attributed to the (Q1.0) and
display improved properties when they are included in me- (Q2.0) vibronic transitions. The broadening and splitting of
soporous materials such as the semiconductor clusters the Q band into two maxima at λmax ϭ 741 nm and
anchored in molecular sieves [14]. [PcZn] was impregnated 698.0 nm, which is not observed in spectra of PcTiO or
onto SiϪMCM-41 by heating it in a solutions of [PcZn] in ureato-TiPcs, may be attributed to the exciton interaction
dry DMF [15]. Palomares et al. [16] described TiPc species between the Pc ligand and the two triphenylsiloxy groups
anchored in nanocrystalline TiO2 films via the axial car- in the axial positions [18]. The IR spectrum of 2 is very
boxylate ligand without the use of co-adsorbents, and the similar to that shown by the same product obtained from
state selective electron injection into the TiO2 was demon- [PcTiCl2] as a starting material [3]. The small absorption
strated to result in an efficient photocurrent generation in band at 821 cmϪ1 in the IR spectrum of 2 is attributed to
a dye sensitized photoelectrochemical solar cell. The choice the antisymmetric stretching of the (OϪSiϪO) group.
of titanium(IV) as a central metal ion allows axial ligation
to the metal atom.
Previously, we reported the synthesis and crystal struc-
ture of a N,N-diphenylureato-TiPc species [17]. In this work
we utilize the reactive dianionic ureato functionality as con-
venient and stable leaving group (as urea), to establish a
straight forward synthetic protocol for the preparation of
other axially substituted [TiPc(L)] complexes via protolysis
with OH-, NH- and SH-acidic substrates. Furthermore we
investigated this strategy to covalently anchor the titanium
phthalocyanine dye on SBA-15 and TiOx@SBA-15.
Results and Discussion
Figure 1. UV/Vis spectrum of (1) (10Ϫ5M, chloronaphthalene).
The ureato leaving group in 1 can be utilized for prep-
aration of other axially substituted titanium phthalocyan-
ines (Scheme 1). The axial ligand exchange reactions of the
The 1H-NMR spectrum of 2 (Figure 2) shows the typical
expected resonance patterns and integration values for the
pure compound 2. In the aromatic region, the phthalocyan-
ine unit shows a characteristic resonance pattern for an un-
substituted Pc with two multiplets: the first multiplet in the
region 9.62Ϫ9.70 ppm for eight protons in the 1,4-positions
and the second multiplet in the region 8.25Ϫ8.32 ppm for
eight protons in the 2,3-positions. The protons of the axial
ligand show upfield-shifted signals due to the well known
ring current effect of the phthalocyanine macrocycle [4].
The aromatic protons of the axial ligand are found in the
region 5.23Ϫ6.87 ppm.
ureato moiety with the incoming ligands proceed smoothly
yielding pure products. The use of [PcTi(ureato)] (1) rather
than [PcTiO] as starting material provides many advantages
because of the better solubility and higher reactivity of 1.
Crystal Structure of 2
The crystal structure of trans-[Ti(OSiPh3)2Pc] (2) is
shown in Figure 3. The compound crystallizes in the centro-
symmetric space group P1 with one molecule per unit cell.
Scheme 1. Axial ligand exchange reactions of 1.
¯
The structure is very similar to that of [(TTP)Ti(OP(Oct)3)2]
[19]. The titanium atom resides in an octahedral environ-
ment with the four nitrogen atoms of the four isoindoline
[PcTi(OSiPh3)2] (2)
Compound 1 reacts with two equivalents of Ph3SiOH rings in the equatorial plane and the two (OSiPh3) groups
forming trans-bis (triphenylsiloxy)phthalocyaninatotitaniu- occupying the axial positions. Owing to a center of
m(IV) (2) (Scheme 1). The blue green compound is air sen- symmetry at titanium, the [TiN4] unit is planar and the
sitive; it turns readily into [PcTiO] in air as indicated by (OSiPh3) groups adopt a staggered trans conformation. A
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Axially Substituted Titaniumphthalocyanines and PcTi@SBA-15 Materials
Figure 4. View of the molecular packing of trans-[PcTi(OSiPh3)2]
(2) in the crystal lattice.
1
Figure 2. H-NMR spectrum of 2, 500 MHz, in C6D5Br, 373 K.
sponding urea derivative is formed as a perfect leaving
group. The IR spectrum of 3 shows the expected absorption
of the NϪH group (νNϪH ϭ 3450 cmϪ1). Thermogravi-
metric analysis (TGA) of compound 3 shows two weight
losses. The first occurs in the temperature range
350Ϫ450 °C and is attributed to the loss of the axial moiety
(C6H4(NH)2), weight loss calcd./found 14/14 % (Scheme 2).
The second one starts at about 600 °C and is attributed to
the thermal destruction of the basic skeleton of the phthal-
ocyanine macrocycle. Such TGA data have been docu-
mented in the literature for other axially substituted Pcs
[20].
cis configuration is not possible because of the high steric
demand of the triphenylsilanolate groups. Some selected
bond lengths and bond angles are given in Table 1.
Scheme 2. Thermal decomposition of the axial moiety of 3.
[PcTiS] (4) and [PcTiS2] (5)
Figure 3. The molecular structure of 2. Displacement ellipsoids at
The reaction of a solution of 1 in chloronaphthalene with
H2S gas in the absence of air yields [PcTiϭS] (4). The mo-
lecular ion of [PcTiϭS] (4) (Mϩ ϭ 592) is detected in EI-
MS and MALDI-TOF. IR spectrum of 4 shows (νTiϭS) at
563 cmϪ1 and in Raman spectrum at 560 cmϪ1, which is in
agreement with values reported for the analogue porphyrins
[6]. A H-NMR spectrum of 4 shows resonance patterns of
a single phthalocyanine product with two multiplets at δ ϭ
8.03Ϫ8.11 and 9.45Ϫ9.59.
the 40 % probability level. (H atoms are omitted for clarity).
˚
Table 1. Selected bond lengths /A and angles /° of 2.
TiϪN1
TiϪN12
Si1ϪO1ϪTi
O1aϪTiϪN1
N1ϪTiϪN12
2.023(13)
2.002(14)
162.97(8)
90.33(5)
90.64(6)
TiϪO1
Si1ϪO1
O1ϪTiϪN1
O1ϪTiϪN12
N1ϪTiϪN12a
1.852(11)
1.627(11)
89.67(5)
90.17(5)
89.36(6)
1
The presence of small amounts of air leads to formation
of perchalcogenido species [PcTiS2] (5). The disulfur com-
pound [PcTiS2] may be formed as a result of an oxidation
of the intermediate [PcTi(SH)2] by oxygen (Scheme 3).
The Raman spectrum of 5 shows (νTiϪS) at 424.6 cmϪ1
and (νSϪS) at 548.4 cmϪ1 and this in accord with the values
reported for the analogue porphyrins at (426.0) and
The molecular packing of 2 is shown in Figure 4. All
molecules are oriented parallel and approach a primitive
hexagonal sphere packing along the a axis.
[PcTi{(NH)2C6H4)}] (3)
Compound (1) reacts with 1,2-phenylenediamine to form (549Ϫ553 cmϪ1) respectively [7]. Comparison of the SϪS
compound 3 in quantitative yield (Scheme 1). The corre- vibration in 5 with the ones in free S2 (725 cmϪ1), ionic
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W. Darwish, S. Schlecht, A. Schaper, M. Fröba, K. Harms, W. Massa, J. Sundermeyer
ARTICLE
Crystal Structure of 5
Compound 5 crystallizes monoclinic in the centrosym-
metric space group P21/n with four molecules per unit cell
(Figure 6). The molecule consists of a six-coordinate ti-
tanium(IV) atom surrounded by four equatorial isoindoline
Scheme 3. Suggested mechanism for the formation of 5. The mole-
cular ion of [PcTiS2] (Mϩ ϭ 624) is detected in EI-MS and
MALDI-TOF. The values of elemental analysis are in agreement
with the calculated values for 5.
rings of the Pc molecule. The S2 group is side-on bonded
to the titanium atom with an average TiϪS distance of
˚
2.320(9) A (Figure 4 and Table 2). The SϪS distance is
˚
2.020(10) A. This is close to the distance found in
[(TPP)Ti(η2-S2)] [7] and is between that expected for ionic
S2Ϫ (589 cmϪ1), and S22Ϫ (446 cmϪ1) indicates that the SϪS
Ϫ
2Ϫ
˚
˚
S2 (2.00 A) and S2 (2.13 A) [21]. The coordination at
the Ti atom is square-pyramidal with the four isoindoline
nitrogen atoms forming the basal plane and the dichalcogen
group at the apical site. The titanium atom is not situated
Ϫ
2Ϫ
bond strength of 5 lies between that of S2 and S2 [7].
The 1H-NMR spectrum of 5 shows two multiplets at
8.38Ϫ8.32 ppm and 9.82Ϫ9.72 ppm. The electronic absorp-
tion spectrum of 5 is similar to that of 4 with a small blue
shift of Q1.0 and Q2.0. A TGA diagram of 5 shows two
weight losses (Figure 5), the first at 220 °C and is attributed
to the loss of the TiS2 moiety as shown in Scheme 4. The
second weight loss is starts about 600 °C and is attributed
to the destruction of the skeletal Pc macrocycle.
˚
in the cavity of the Pc macrocycle, but is located 0.708(5) A
above the plane of the four nitrogen atoms. This distance
˚
is comparable to the corresponding distance of 0.658(1) A
observed for [(TPP)Ti(η2-S2)] [7]. Such “atop” situation is
well known for analogue complexes and called extra-coor-
dination. This out-of-plane displacement of the ti-
tanium(IV) atom from the N4 core of the Pc ligand, drives
the macrocycle to adapt to this special situation by defor-
mation [22]. Here, the maximum deviation from the best
˚
plane through all phthalocyanin atoms is 0.28(2) A. Similar
coordination schemes are documented in the literature for
peroxo-, disulfur-, and diselenium analogues [7]. The TiϪN
distances parallel to the SϪS bond [TiϪN(1) ϭ 2.13(2),
˚
TiϪN(3) ϭ 2.09(2) A] are somewhat larger than the
ones perpendicular to this group [TiϪN(2) ϭ 2.05(2),
˚
TiϪN(4) ϭ 2.05(2) A]. Some further selected bond lengths
˚
(A) and bond angles (deg.) of 5 are given in Table 2. A
comparison between some structural parameters of 5 and
[(TPP)Ti(η2-S2)] is shown in Table 3.
˚
Table 2. Selected structural parameters (in A and degrees) of 5.
Low precision because of very small crystal. Data for the TiS2 unit
see Table 3.
Figure 5. TGA diagram of 5.
TiϪN1 2.13(2) N1ϪTiϪN2 84.8(8) N1ϪTiϪN3 138.4(8)
TiϪN2 2.05(2) N1ϪTiϪN4 81.5(7) N2ϪTiϪN4 141.7(7)
TiϪN3 2.09(2) N2ϪTiϪN3 83.6(8) N1ϪTiϪS1 87.5(5)
TiϪN4 2.13(2) N3ϪTiϪN4 83.4(8) N3ϪTiϪS2 82.5(6)
Scheme 4. Thermal decomposition of the axial moiety of 5.
˚
Table 3. Comparison between some structural parameters (in A,
degrees) of 5 and [(TPP)Ti(η2-S2)] [7].
The reaction of [PcTiO] with P4S10 was found to result
in the formation of a mixture of [PcTiS] (Mϩ ϭ 592) and
[PcTi(η2-S2)] (Mϩ ϭ 624) (Scheme 5). Reduction of the
[PcTi(η2-S2)] portion was achieved successfully by reaction
of the mixture with melted Ph3P at 160 °C yielding a homo- S1-S2
geneous product of [PcTiS] (4). The byproduct Ph3PϭS had
Structural parameter
PcTi(η2-S2) (5)
(TpTP)Ti(η2-S2)
TiϪS1
TiϪS2
2.313(9)
2.327(9)
2.020(10)
51.6(3)
64.6(3)
63.8(3)
2.283(2)
2.311(2)
2.042(2)
52.78(6)
64.30(7)
62.92(8)
S1ϪTiϪS2
S2-S1-Ti
S1-S2-Ti
to be removed by extraction with different organic solvents.
The molecular packing of 5 (Figure 7) can be charac-
terized by “face-to-face dimers” generated by an inversion
˚
center and shifted against each other by about 3.5 A. The
distance between the best planes calculated by all C, N
˚
atoms of the Pc units is 3.31 A only, indicating πϪπ interac-
Scheme 5. Synthesis of [PcTiS] (4) starting from [PcTiO].
tion similar to that in the imido and ureato-TiPcs [17]. In
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Axially Substituted Titaniumphthalocyanines and PcTi@SBA-15 Materials
while the TiOx species remained fixed via a SiϪOϪTi link-
age at the surface of SBA-15. According to AAS we ob-
tained a titanium loading of about 2.66 wt.-% and this
value is comparable to that achieved applying this method
for MCM-41 materials where loadings of 1.7Ϫ8.6 % were
reported [12 b]. The lower titanium loading in the pores
compared with that achieved for MCM-41 using TiO(acac)2
may be attributed to the weaker interaction of TBOT with
the OH groups because of its hydrophobic hydrocarbon
chain [12 b]. While high loadings (30Ϫ80 %) of TiO2 in
SBA-15 led to the presence of anatase [9], the material
TiOx@SBA-15 prepared in this work having relatively low
titanium loading displays monodispersed isolated TiIV sites.
This is in agreement with other reports of SBA-15 materials
of low titanium loading [8, 10, 11]. Raman spectrum of the
prepared TiOx@SBA-15 shows absorption bands at 789,
832 cmϪ1 assigned to the SiϪOϪSi linkage, and at 488 and
601 cmϪ1 assigned to four and three membered siloxane
rings [24]. The absence of the typical Raman absorption
bands of anatase TiO2 (638, 519, 399, 147 cmϪ1) ensures
the absence of the anatase [8]. It is suggested that due to
the strong extraction of the unreacted TBOT under inert
atmosphere and low titanium content TiIV is only coval-
ently bonded to the surface of SBA-15 via 1Ϫ3 TiϪOϪSi
links forming thin layer of TiOx. The good ureato leaving
group in 1 results in smooth reaction with the silanol
groups of Ph3SiOH. In the following part, compound 1 was
used to anchor and fix the TiPc dye in the pores of SBA-
15 and TiOx@SBA-15 where the titanium atom in 1 can
smoothly link to the silanol groups in SBA-15 molecular
sieves (Figure 8).
Figure 6. Top view of 5 with atom labeling Scheme. Displacement
ellipsoids (isotropic for C and N atoms) at the 50 % probability
level.
the latter compound, the distance between the Pc planes is
˚
˚
3.50 A and the shift about 2.5 A. In 5 the molecule pairs
are stacked along the a axis to columns. Equivalent col-
umns with mutual perpendicular orientations of the Pc
planes are packed in the way of a hexagonal rod packing.
No close S···S contacts are observed.
Several samples were included in this study (Scheme 6).
In Sample A the conventional silica (SiO2) was heated with
a dilute solution of the phthalocyanine dye. In Sample B
the SBA-15 material was heated with a dilute solution of
the phthalocyanine dye. Consequently, the TiPc species are
expected to be immobilized predominantly inside the chan-
nels to give the modified material shown in Figure 8. In
Sample C the prepared TiOx@SBA-15 (Ti 2.66 wt.-%) was
heated with a diluted solution of 1 and since some surface
silanol groups are still unreacted, the hypothetical mono-
layer coverage of SBA-15 with TiOx is about 35 wt.-% [10],
the dye molecules are presumably covalently bound via the
remaining silanol groups or via the TiϪOH groups which
may be present at the TiOx(OH)y sites (Figure 8).
Figure 7. The molecular packing of [PcTi(η2-S2)] (5).
Anchoring of 1 onto SBA-15 and (TiOx@SBA-15)
The methods we applied to prepare SBA-15 were re-
ported previously in the literature [23]. For the preparation
of (TiOx@SBA-15), we used a method similar to that pre-
viously used for impregnation of titanium species [12, 15].
Thus titanium species were impregnated in a previously
synthesized calcined siliceous SBA-15 using tetrabutylor-
thotitanate (TBOT) as a precursor of titanium species. It is
Scheme 6. Preparation of PcTi@silica, PcTi@SBA-15, and
known, that TBOT interacts with the surface silanol groups PcTi&TiOx@SBA-15 materials.
of SBA-15 [12]. In our experiments, unreacted TBOT was
removed by extraction with dried solvents under inert con-
In all samples the physically adsorbed phthalocyanine
ditions. During the following calcination in air at 600 °C, dye was supposed to be removed by intensive extraction of
the remaining butoxy ligands are assumed to be burned off all samples with different organic solvents such as toluene,
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W. Darwish, S. Schlecht, A. Schaper, M. Fröba, K. Harms, W. Massa, J. Sundermeyer
ARTICLE
Figure 8. Covalent anchoring of [PcTi] onto different SBA-15 materials.
MeCN and chlorobenzene. Finally, the samples were dried grounded in a mortar and when the dye is covalently anch-
at high vacuum.
ored onto the pores by heating the SBA-15 with the dye
solution. In another work [17], we reported the crystal
structures of two PcTi(diarylureato) compounds and dis-
cussed the molecular packing of the molecules in the unit
cell. We identified that the PcTi(ureato) complex (1) exists
in the solid state as dimeric species in a face to face configu-
Mass Spectrometry
In mass spectrometric measurements (MALDI-TOF) of
all prepared samples the ion peak of [PcTiϩ] m/z ϭ 560
instead of the molecular ion peak of N,NЈ-di-4-tolylurea-
to(phthalocyaninato)titanium(IV) (1). This is giving rise to
the assumption that the ureato complex reacted with the
silanol groups on the surface of the SBA-15 material. The
formed urea derivative (TolNHCONHTol) was extracted
from the produced materials by successive washing by sev-
eral organic solvent such as boiling acetonitrile.
Ti Analysis
The amounts of the loaded titanium in TiOx@SBA-15
and PcTi&TiOx@SBA-15 were determined by using Atom
Absorption Spectra (AAS) and the following results were
obtained:
%Ti in TiOx@SBA-15 ϭ 2.66
%Ti in PcTi&TiOx@SBA-15 (Sample C) ϭ 3.44
%Ti because of PcTi dye ϭ 0.78 (consequently content of
PcTi-dye ϭ 9.13 %).
Absorption Spectra of the Prepared Materials
The absorption spectra (200Ϫ2000 nm) of pure meso-
porous and conventional silica, pure Pc dye, dye/silica mate-
rials and mechanical mixture of dye and silica are shown in
Figure 9. The measurements involved also a mechanically
ground mixture of the respective silica and ureato-TiPc for
comparison. It is apparent that the spectral patterns are dif-
ferent and this is attributed to different interactions of the
Figure 9. Absorption spectra of several materials (powder measure-
dye with the silica when the components are mechanically ments).
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Axially Substituted Titaniumphthalocyanines and PcTi@SBA-15 Materials
ration. The absorption band of 1 at about 800 nm in the and the two prepared materials due to the different compo-
UV/Vis spectrum of the solid is attributed to this dimeric sitions of each material. The appearance of the basic ab-
stacking in solid phthalocyanines. [17] This absorption sorptions of the titaniumphthalocyanine dye emphasizes
band is not observed in the solution spectrum because of the inclusion of the dye in the impregnated materials. The
the absence of the dimeric stacking of the molecules in solu- absence of (νTiϭO at 965 cmϪ1) [25] rules out the assump-
tions (Table 4). The presence of this band in the mechanical tion that [PcTiO] may be formed and hydrogen bonded to
mixtures of the PcTi(ureato) compound (1) with SiO2 or the OH groups at the pores surface.
SBA-15 indicates that the dimeric stacking of the phthalo-
cyanine molecules is present in these mixtures. However, the
Table 5. Raman bands of the prepared materials.
Wavenumber /cmϪ1
absence of this band in (PcTi(ureato)@SiO2) and (PcTi[ure-
ato]@SBA-15), as previously observed in Pc solutions, gives
strong support for the assumption that the Pc molecules are
anchored as monomers on the template and not stacked in
dimeric configuration any more.
Material
PcTi(ureato) (1)
1506, 1491, 1449, 1433, 1338, 1303,
1212, 1192, 1142, 1104, 1009, 971, 938, 835,
751, 677, 591, 484, 308, 254, 235, 216, 188.
1611, 1529, 1511, 1451, 1432, 1338, 1304,
1210, 1190, 1142, 1104, 952, 937, 835, 778,
749, 677, 589, 483, 215.
PcTi@SBA-15,
(Sample B)
Table 4. UV/Vis Spectroscopic Data of 1 and Pc-modified SBA-
15 Materials.
PcTi&TiOx@SBA-15, 1528, 1514, 1453, 1433, 1338, 1307, 1210,
(Sample C)
1190, 1143, 1105, 953, 938, 837, 825, 780,
751, 679, 599, 485, 236, 217.
Material
λ max /nm
PcTi(ureato) (1) solid 306
575 716
602 713
828
818
932
930
PcTi(ureato)/SiO2
(mechanical mixing)
PcTi(ureato)/SBA-15
(mechanical mixing)
PcTi(ureato)@SiO2
(Sample A)
PcTi@SBA-15
(Sample B)
PcTi(ureato) (1)
310
329
324
340
347
586 702 (w) 793
ϪϪ
Transmission Electron Microscopy (TEM) on
(TiPc@SBA-15) Material
612 700
640 698
629 697
ϪϪ ϪϪ
ϪϪ ϪϪ
ϪϪ ϪϪ
The material (PcTi@SBA-15) (Sample A) obtained from
anchoring of (ureato)TiPc on SBA-15 was investigated by
electron microscopy. Transmission electron microscopy
(TEM) images were taken for the on-top view and a cross-
section of the pore system (Figure 11). The TEM micro-
graphs show small and very distributed dark contrasts from
the metal-containing dye anchored on the wall surface. No
extended areas of accumulated dye molecules are found on
the micrographs, which is in good accordance with the UV/
Vis spectroscopic data indicating the presence of individual
non-aggregated phthalocyanine molecules anchored to the
pore walls. Consequently, the observed dark spots in the
TEM micrographs are evenly spread over the pore walls but
are not found in the pore volume.
Solution in ClN
Experimental Section
Spectroscopic Methods
The UV/Vis absorption spectra were recorded with a Hitachi-U310
spectrophotometer in chloronaphthalene for phthalocyanine
derivatives and as solid pellets for (PcTi@SBA-15) and
(PcTi/TiOx@SBA-15) materials. IR spectra were recorded with a
Bruker IFS 588 spectrophotometer with KBr pellets. The following
abbreviations were used to identify the intensities of the bands: vs.
(very strong), s (strong), m (medium), w (weak), vw (very weak), br
(broad), and sh (shoulder). ν˜ ϭ Wave-number /cmϪ1. EI-mass
spectra were measured with a CH7 mass spectrometer, Varian
MAT (450 °C, 10Ϫ6 Torr, 70 eV), MALDI-TOF measurements
were carried out by using a Bruker Flex III, in dry MeCN, without
addition of an energy transfer matrix, the m/z-values refer to the
isotopic ratio according to the natural abundance of the isotopes.
Elemental analysis was carried out by using Elementar-Vario EL,
burning of samples was carried out at 950 °C. TGA measurements
Figure 10. Raman spectra of [PcTiO], [PcTi(ureato)] (1),
(PcTi@SBA-15), and (PcTi/TiOx@SBA-15). The dotted lines are
hand made for an ease comparison.
Raman Spectra
Raman spectra (RS) of N,NЈ-di-4-tolylureato-
(phthalocyaninato)titanium(IV) (1), PcTi@SBA-15, and
PcTi&TiOx@SBA-15 at λ(exc) ϭ 632 nm are shown in Fig-
ure 10 and the band positions are reported in Table 5. (Line
1 and 2) in Figure 10 are made for comparison of the most
important band positions in the spectra of the prepared ma-
terials. There are remarkable differences in the spectra of 1 were recorded on TGA/SDTA 851 by Mettler-Toledo.
Z. Anorg. Allg. Chem. 2009, 1215Ϫ1224
© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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1221

W. Darwish, S. Schlecht, A. Schaper, M. Fröba, K. Harms, W. Massa, J. Sundermeyer
ARTICLE
Table 6. Crystallographic data, measurement and refinement condi-
tions of 2 and 5.
Crystal data
(2)
C68H46N8O2Si2Ti C32H16N8S2Ti
1111.21 624.55
(5)
Molecular formula
Formula mass
Crystal description
Crystal size /mm
Crystal system
Space group
prism, dark green block, black
0.38 ϫ 0.32 ϫ 0.27 0.045 ϫ 0.03 ϫ 0.03
triclinic
P1
monoclinic
P21/n
¯
˚
Unit cell a /A
10.4160(8)
11.2160(8)
13.1495(9)
114.124(5)
99.452(6)
96.174(6)
1356.7(2)
1
13.114(3)
9.752(2)
20.975(5)
˚
b /A
˚
c /A
Ͱ /°
β /°
γ /°
100.46(2)
3
˚
Volume /A
2637.9(10)
4
Z
Dcalcd. /g·cmϪ3
Absorption μ /mmϪ1
Data collection
Diffractometer
Radiation
1.360
0.259
1.573
0.524
IPDS-II (Stoe)
MoKα graphite monochromator
˚
(λ ϭ 0.71073 A)
Temperature /K
θmax /°
Reflections total
Refinement
193(2)
25.14
19504
100(2)
25.00
16523
Reflections unique, >2σ(I) 4490, 3751
Parameters 459
Residuals R, wR2 (all refl.) 0.0401, 0.0852
4643, 912
188
0.444, 0.349
0.198, 0.225
1.001
(observed refl.)
Goodness of fit S
0.0315, 0.0823
1.050
Ϫ3
˚
δρ (max, min) /e· A
0.283, Ϫ0.370
0.568, Ϫ0.947
Figure 11. (A) on-top view of the hexagonal pore array with dark
contrasts showing the presence of titanium phthalocyanine in the
pores; (B) cross-section of the ordered pore system where dark
spots originating from the dye can be seen on the pore wall.
Syntheses
All manipulations of reagents and products were carried out under
an inert atmosphere of nitrogen by using a glove box (Type MB
150 BG II or LABMASTER 130 Braun) or on a vacuum line by
using standard Schlenk technique. All solvents were thoroughly
dried in an appropriate manner, distilled, and kept under nitrogen
over molecular sieves. All organic reagents were purchased as a
pure grade from Acros and used as received. Chloronaphthalene
was purchased as a mixture of 90 % α- and 10 % β-chloronaph-
thalene. [PcTiO] was prepared according to the literature pro-
cedure [28].
Crystal Structure Determinations
All crystals were isolated under scrupulously oxygen-free con-
ditions and their X-ray crystallographic data were collected on an
IPDS-2 area detector system using a graphite monochromated
˚
Mo-Kα radiation (λ ϭ 0.71073 A). For 4 only very small crystals
could be obtained. Thus, only about 20 % of the reflections were
>2σ(I) and the quality of the structural data is rather low, therefore.
The structures were solved by direct methods using the program
SIR2002 [26] and refined on F2 by full-matrix least-squares using
SHELXL-97 [27]. The crystal data and experimental conditions are
collected in Table 6. For 2 all non-hydrogen atoms were refined
using anisotropic displacement parameters, for 4 the titanium and
sulfur atoms only. The hydrogen atoms were kept riding on
calculated positions with isotropic displacement factors taken as
1.2 times (1.5 times for CH3) the Ueq value of the corresponding
carbon atom. Crystallographic data (excluding structure factors)
for the structures reported in this paper have been deposited with
the Cambridge Crystallographic Data Center as supplementary
(i) N,NЈ-Di-4-tolylureato(phthalocyaninato)titanium(IV) (1): This
compound was prepared as described elsewhere [17] by reaction of
[PcTiO] with an excess of 4-tolylisocyanate in chloronaphthalene.
(ii) Synthesis of trans-[PcTi(OSiPh3)2] (2):
A mixture of (1)
(400 mg, 0.5 mmol) and triphenylsilanol (550 mg, 2 mmol) was re-
fluxed in chlorobenzene (40 mL) for 1 hr. The reaction mixture was
gradually cooled from 130 °C to room temperature within 3 hrs
giving dark-green crystals suitable for X-ray structure determi-
nation. Afterwards the crystals were filtered off, washed with
MeCN, toluene, and pentane and dried under vacuum to give
trans-bis(triphenylsiloxy)phthalocyaninatotitanium(IV) (2). Yield:
620 mg (92 %), C68H46N8O2Si2 Ti (1111.2): calcd. C 73.50 H 4.17
publication no. CCDC-287958 (2) and -287959 (4). Copies of the N 10.08; found C 72.75 H 4.65 N 9.50. MS (MT): m/z ϭ 1111
data can be obtained free of charge on application to CCDC,
12 Union Road, Cambridge CB2 1EZ, UK [Fax: int. Code
ϩ44(1223)336-033; E-Mail: deposit@ccdc.cam.ac.uk].
[Mϩ]. UV/Vis (ClN): λmax ϭ 741.5 (m), 698.0 (s), 663.5 (sh), 627.0
(w), 356.5 (m) nm. IR (KBr): ν˜ ϭ 1590(m)(νCϭCarom.), 1429(m),
1305(s), 1104(m), 1043(s), 998(w), 971(w), 944(w), 886(vs),
1222
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© 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2009, 1215Ϫ1224

Axially Substituted Titaniumphthalocyanines and PcTi@SBA-15 Materials
821(w)(νOϪSioop), 800(w), 766(w), 736(m), 711(m), 707(m), 697(s) gas was followed but in presence of air and heating at 180 °C for
cmϪ1
.
6 hours. The final product was identified as [PcTiS2] (5), yield
210 mg (67 %), C32H16N8S2Ti (624.53): calcd. C 61.54, H 2.58, N
17.94, S 10.30; found C 62.68, H 2.97, N 18.16, S 7.74. MS (MT):
m/z ϭ 624.2 [Mϩ]. UV/Vis (ClN): λmax ϭ 699 (s) (Q0,0), 665.4 (w)
(Q0,1), 337.1 (s) (B band) nm. Raman spectra: ν˜ ϭ 1606.5, 1515.8,
1430.8, 1386.4, 1334.5, 1105.0, 1026.8, 833.9, 677.2, 590.2, 559.2,
(iii) Synthesis of [PcTi{(NH)2C6H4}] (3): A mixture of (1) (400 mg,
0.5 mmol) and 1,2-phenylenediamine (220 mg, 2 mmol) in chloro-
naphthalene (20 mL) was heated at 160 °C for 2 hours. The product
was precipitated by addition of hexane (20 mL). The precipitate
was filtered off and washed by successive extractions with refluxing
MeCN, toluene (5x50ml), and washed with pentane and dried
under vacuum to give 1,2-phenylenediimino(phthalocyaninato)-
titanium(IV) (3). Yield: 270 mg (82 %), C38H22N10Ti (666.5): calcd.
C 68.48, H 3.33, N 21.01; found C 67.63, H 3.35, N 20.26. MS
(MT): m/z ϭ 666 [Mϩ]. UV/Vis (ClN): λmax ϭ 698.5(s) (Q0,0),
668.0(sh) (Q1,0), 629.5(m) (Q2.0), 337.0(s) (B) nm. IR (KBr): ν˜ ϭ
3450(m)(νNH), 1606(w), 1491(w), 1476(w), 1414(w), 1330(s),
1283(m), 1230(w), 1160(w), 1117(s), 1074(vs), 892(m), 826(w),
548.4(νSϪS), 484.1, 424.6(νTiϪS), 560.0 cmϪ1
.
1H NMR (500 MHz, C6D5Br, 373 K): δ ϭ 8.32Ϫ8.38 [m, 8H(α)],
9.72Ϫ9.83 [m, 8H(β)].
748(s), 724(vs) cmϪ1
.
(iv) Preparation of Sulfido(phthalocyaninato)titanium(IV) (4)
a) By Reaction of 1 with H2S Gas: Into a solution of 400 mg
(0.5 mmol) of (1) in chloronaphthalene (20 mL) in a sealed teflon
valve container, dry H2S gas (1 bar) was bubbled for five minutes
under a cover of nitrogen gas. The container was tightly closed and
the solution was stirred at 160 °C for 3 hours. After cooling and
removing of the gas, the product was precipitated by addition of
hexane (about 10 mL). The produced bluish-green solid was col-
lected on a glass frit and washed with MeCN (5 ϫ 50 mL) and
finally with pentane. The product PcTiϭS (4) was dried at 120 °C /
10Ϫ3 mbar for 3 hours. The product (4) yield: 160 mg (50 %),
C32H16N8STi (592.4): calcd. C 64.87, H 2.72, N 18.91, S 5.42;
found C 64.60, H 3.20, N 18.44, S 4.17. MS (MALDI-TOF): m/
z ϭ 592.3 (Mϩ), 560.3 (MϩϪS). UV/Vis (ClN): λmax ϭ 696.0 (s)
(Q0,0), 667.0 (w) (Q1,0), 635.5 (w) (Q2,0), 339.0 (s) (B) nm. IR (KBr):
(vi) Preparation of SBA-15: SBA-15 was prepared according to the
procedure given in literature [23]. The material was dried at 200 °C,
10Ϫ3 mbar for 20 hours before use.
(vii) Preparation of (TiOx@SBA-15): A sample of the previously
synthesized and dried SBA-15 (200 mg) was suspended in dry etha-
nol (20 mL) for 30 min. Afterwards, excess of TBOT (1 mL) was
added and the mixture was stirred at room temperature for
24 hours. The solid was filtered and washed with dry methanol
(3 ϫ 30 mL) and finally dried at 120 °C/10Ϫ3 mbar for 2 hours.
The solid was calcined in air at 600 °C for 24 hours to give
TiOx@SBA-15 (Ti ϭ 2.66 wt%).
(viii) Anchoring of Titanium Phthalocyanine Dye on SBA-15 and
(TiOx@SBA-15): A solution of N,NЈ-di-4-tolylureato(phthalocyan-
inato)titanium(IV) (1) (200 mg) in chloronaphthalene (30 mL) was
heated at 373 K under inert atmosphere until the solution was
clear. About 20 mL of this solution were filtered using a microfilter
(0.45 μL) and then added to dried silica SiO2 (100 mg) (Sample A),
SBA-15 (100 mg) (Sample B) or TiOx@SBA-15 (100 mg)
(Sample C). The mixture was stirred at 150 °C for 6 hours. The
faint-green solid was filtered and washed with refluxing chloroben-
zene, toluene, MeCN, and with pentane and dried at 120 °C/10Ϫ3
mbar for 2 hours.
ν˜
1287(m), 1160(w), 1118(vs), 1071(vs), 1053(vs), 894(s), 778(m),
751(s), 730(vs), 563(m) (νTiϭS), 501(w), 411(vw) cmϪ1
ϭ 1647(m),1608(w), 1553(br), 1491(s), 1415(m), 1332(vs),
.
1H NMR (500 MHz, C6D5Br, 373 K): δ ϭ 8.03Ϫ8.11 [m, 8H(α)],
9.45Ϫ9.59 [m, 8H(β)].
b) By Reaction of [PcTiO] with P4S10: A mixture of [PcTiO]
(300 mg, 0.52 mmol) and P4S10 (230 mg, 0.52 mmol) in chloron-
aphthalene (10 mL) was heated at 160 °C for 10 hours. The color
turns dark green. After cooling, the product was precipitated by
addition of hexane (20 mL). The precipitate was collected on a
glass frit and washed by extraction from refluxing MeCN
(3 ϫ 50ml), refluxing toluene (3x50ml) and finally washed with
pentane. The solid was dried at 120 °C/10Ϫ3 mbar for 1 hour. A
sample (200 mg) of this product (mixture of PcTiS and PcTiS2) was
heated with Ph3P (1 g) to a melt (160 °C) under nitrogen atmos-
phere for 4 hours. The blue-green mass was washed by successive
extractions from refluxing MeCN (5 ϫ 50 mL) and refluxing tolu-
ene (5 ϫ 50 mL). The product (4) was finally washed with 50 mL
of ether and dried at 120 °C/10Ϫ3 mbar for 3 hours. Yield:
170 mg (57 %).
Acknowledgement
Support by the Fonds der Chemischen Industrie is gratefully
acknowledged.
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Z. Anorg. Allg. Chem. 2009, 1215Ϫ1224
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1223

W. Darwish, S. Schlecht, A. Schaper, M. Fröba, K. Harms, W. Massa, J. Sundermeyer
ARTICLE
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Received: September 8, 2008
Published Online: April 8, 2009
1224
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Z. Anorg. Allg. Chem. 2009, 1215Ϫ1224