Non-aggregated intercalation of dicationic tetraphenylporphyrinatoantimony(V) complexes into smectite clay layers

Article abstract of DOI:10.1246/cl.2003.484

Adsorption and intercalation of +2 charged cationic [3-(trimethylammonio)propoxo(methoxo)(tetraphenylporphyrinato)antimony(V)] ²⁺ (1a) into an artificially synthesized smectite clay were studied. The red shift of Soret band in UV-spectra for 1a

Full text of DOI:10.1246/cl.2003.484

484
Chemistry Letters Vol.32, No.6 (2003)
Non-aggregated Intercalation of Dicationic Tetraphenylporphyrinatoantimony(V) Complexes
into Smectite Clay Layers
Tsutomu Shiragami,ꢀ Keiko Nabeshima, Jin Matsumoto, Masahide Yasuda, and Haruo Inouey
Department of Applied Chemistry, Faculty of Engineering, Miyazaki University, Gakuen-Kibanadai, Miyazaki 889-2192
yCREST, JST (Japan Science and Technology)
(Received February 14, 2003; CL-030127)
Adsorption and intercalation of þ2 charged cationic [3-(tri-
methylammonio)propoxo(methoxo)(tetraphenylporphyrinato)-
antimony(V)]2þ (1a) into an artificially synthesized smectite
clay were studied. The red shift of Soret band in UV-spectra
for 1a in an aqueous colloidal clay solution and analyses of
X-ray diffraction of the obtained complex between 1a and the
clay indicate the intercalation of 1a into the clay interlayer. Am-
monium cationic part on an axial ligand led to the effective non-
aggregated intercalation of 1a into the clay.
Intercalation of some functional molecules into multi-
layered inorganic materials such as clays has been extensively
studied from the interesting as providing nanospace chemical
reaction sites.1;2 Several studies on the interaction between por-
phyrin and cation exchangeable clays have recently reported
from the viewpoints of unique photochemical reaction in nano-
space interlayer.3;4 In these clay systems, the aggregation of
porphyrin molecules was often observed,2 and caused a disad-
vantage for a photoreaction owing to decrease of the excited
state lifetime. Therefore, the control of aggregation is necessary
to make photoreaction effective in the clay system. Recently,
we have reported that the intercalation of new type of cationic
dihydroxo(porphyrinato)antimony(V) complex into an artifi-
cially synthesized cation-exchangeable smectite clay (Sumecton
SA; SSA) was effectively induced. Although the structure of
Figure 1. Schematic diagram of possible layered structure.
was observed in hydroxo axial ligand system.5 These spectral
changes clearly demonstrated the adsorption and aggregation
of 1b onto the surface or in the interlayer space of SSA7 How-
ever, the absorption spectra of 1a did not show the larger red
shift and further broading of Soret band with an increase of
%LL, suggesting that the p–p interaction between porphyrin
rings each other should be weaker in 1a-SSA system. 1a, b were
adsorbed onto SSA quantitatively, since no absorption peaks of
1a, b were detected in their filtrates by the filtration of 1-SSA
powders whereas free 1a, b were observed in the aqueous
SSA colloidal solution at a 120%LL.
X-ray diffraction (XRD) analysis was performed for the
samples prepared by filtration of the above mixture through a
membrane filter (pore size = 1 mm) and drying at room tem-
perature. In the case of 1a-SSA complex, some broad diffraction
peaks were observed on XRD measurement, indicating that the
layer structure of SSA should be kept irrespective of the addi-
tion of 1a (Figure 3A). As an increase of %LL, the interlayer
distance of 1a-SSA complex increased to reach 1.03 nm in
100 %LL, as shown in Figure 3B. According to PM3 calcula-
tion, the thickness of 1a for axial ligand direction was estimated
to be ca. 0.94 nm. This value is almost consistent with the inter-
layer distance (1.03 nm) of 1a-SSA complex. These results
strongly suggest that 1a should be intercalated into SSA inter-
their axial ligands was an important factor for providing a com-
plete intercalated porphyrin-SSA complex, axial hydroxo ligand
did not prevent the aggregation in SSA interlayer5 If the dis-
tance and orientation of porphyrin ring in interlayer of anionic
SSA sheets can be controlled by the introduction of cationic ax-
ial ligand, it will be expected to prevent the aggregation of por-
phyrin in SSA interlayers. Here, we report on the adsorption and
intercalation behaviors of novel 3-trimethylammoniopropoxo-
and 3-dimethylaminopropoxo-(methoxo)(tetraphenylporphyri-
nato)antimony(V) complexes (1a, b)6 into SSA, as shown in
Figure 1.
The measurement of absorption spectra was performed for
a solution prepared by mixing the aqueous solution of 1a, b
(5:0 Â 10À6 mol dmÀ3
)
with
colloidal
SSA
solution
(50 mg dmÀ3).5 The loading level of 1a, b vs cationic exchange
capacity of SSA (%LL) were adjusted by the addition of vari-
able amounts of SSA to constant concentration of 1a, b.
Figure 2 shows the absorption spectra of 1a, b under the condi-
tions of various %LL in aqueous colloidal SSA solution. At low
%LL (10–20%), the ꢀmax of Soret band of 1a (418 nm) and 1b
(419 nm) was shifted to a longer wavelength (431 nm). In the
case of 1b, an increase of %LL led the further red shift of
ꢀmax and the broading of Soret band. Similar spectral change
Copyright Ó 2003 The Chemical Society of Japan

Chemistry Letters Vol.32, No.6 (2003)
485
be achieved in SSA interlayer. This is a first example for the in-
tercalation of dicationic porphyrin system having both axial li-
gand part and porphyrin part into the clay layer. The above re-
sults show the importance of the axial ligand structure as to how
to control the aggregation of porphyrins in interlayer space of
clay.
This research was supported by a Grand-in-Aid for Scienti-
fic Research (No. 14050079. Scientific Research in Priority
Areas 417) from the Ministry of Education, Science, Sports,
and Culture. We are grateful to Mr. Kukizaki and Ms. Akazaki
(Miyazaki Prefecture Industrial Technology Center) for XRD
measurement.
References and Notes
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2
a) K. Takagi and T. Shichi, ‘‘Solid State and Surface Photochem-
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New York (2000), Vol. 5, p 31. b) M. Ogawa and K. Kuroda,
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328 (1990). d) I. Ukrainczyk, M. Chibwe, T. J. Pinnavaia, and
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Shinoda, K. Aichi, K. Suzuki, and Y. Izumi, Mol. Cryst. Liq.
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4
a) S. Takagi, T. Shimada, M. Eguchi, T. Yui, H. Yoshida, D. A.
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(2002).
Figure 2. Absorption spectra of 1a and 1b at various
%LL for aqueous SSA solution.
layer space at a high %LL, and that the orientation of the por-
phyrin plane should be almost parallel to the SSA clay layer, as
shown in Figure 1. If the orientation of 1a is vertical to the clay
layer, the expanded interlayer distance should be about 1.75 nm.
On the other hand, XRD measurements for 1b-SSA complex
gave no diffraction peaks, indicating that SSA should become
amorphous by the addition of 1b, as shown in previous report.5
Accordingly, these results show that 1b-SSA complex can not
take the layer structure but adsorbed and aggregated on SSA
surface.
Thus, it is clear that the ammonium cationic group as an ax-
ial ligand was effective not only for the intercalation into SSA,
but for non-aggregation of porphyrin. The axial cationic part
gave the fine intercalated structure where the porphyrin rings
could be located with the alternate orientation (head-to-tail)
probably owing to the strong Coulombic attractive force with
anionic clay sheets, resulting that non-aggregation of 1a can
5
6
T. Shiragami, K. Nabeshima, M. Yasuda, and H. Inoue, Chem.
Lett., 2003, 148.
Preparation of 1a, b: Mono-methanolysis of dibromo(tetraphenyl-
porphyrinato)antimony(V) ([Sb(tpp)Br2]þBrÀ) was performed in
MeOH–MeCN (1:1) to give [Sb(tpp)(Br)(OMe]þBrÀ.8 An
MeCN–pyridine solution (5:1v/v 50 mL) containing
[Sb(tpp)(Br)(OMe]þBrÀ (1.1 mmol) and N,N-dimethyl-3-amino-
1-propanol (30 mmol) was heated for 2 h at 65 ꢁC. The solvent
was evaporated and then solved in CH2Cl2. The CH2Cl2 solution
was washed three times with 50 mL portions of H2O. After eva-
poration, the crude product was chromatographed on SiO2 using
CHCl3–MeOH (10:1, v/v) as an eluent to give 1b. MeI (32 mmol)
was added in an MeCN–pyridine solution (5:1v/v 50 mL) con-
taining 1b and then heated for 2 h at 65 ꢁC for methylation of di-
methyl amino group. The purification of 1a was performed by
same procedure with 1b. 1b: Yield 80%; UV-vis (MeOH) ꢀmax
/
nm (log e): 419 (5.58), 551(4.25), and 591(4.09); SIMS:
m=z
866 (Mþ-2H); 1H NMR (CDCl3/ppm) d À2:65 (2H, t, J ¼
6:2 Hz –OCH2–), À2:29 (3H, s, –OCH3), À1:58 (2H, quint,
J ¼ 6:2 Hz, –CH2–), À0:20 (2H, t, J ¼ 6:2 Hz, –CH2–N–), 1.40
(6H, s, –N(CH3)2), 7.79–7.93 (12H, m, Ph), 8.23 (4H, d, J ¼
6:7 Hz, Ph), 8.34 (4H, d, J ¼ 6:7 Hz, Ph), 9.48 (8H, s, pyrrole).
1a: Yield 94% from 1b; UV-vis (MeOH) ꢀmax/nm (log e): 419
(5.48), 551(4.15), and 591(3.93); SIMS: m/z 881(M
þ-2H);
1H NMR (CDCl3/ppm) d À2:59 (2H, t, J ¼ 6:0 Hz, –OCH2–),
À2:24 (3H, s, –OCH3), À1:14 (2H, quint, J ¼ 6:0 Hz, –CH2–),
0.89 (2H, t, J ¼ 6:0 Hz, –CH2–þN–), 2.18 (9H, s, –þN(CH3)3),
7.83–8.00 (12H, m, Ph), 8.24 (4H, d, J ¼ 6:6 Hz, Ph), 8.67 (4H,
d, J ¼ 6:6 Hz, Ph), 9.58 (8H, s, pyrrole).
7
8
M. Kasha, H. R. Rawls, and M. A. El-Bayoumi, Pure Appl.
Chem., 11, 371(1965).
Figure 3. (A) The XRD profile of 1a-SSA at %LL = 80%.
(B) Relationship between the %LL and the interlayer dis-
tance determined by XRD measurement of 1a-SSA.
T. Shiragami, Y. Andou, Y. Hamasuna, F. Yamaguchi, K. Shima,
and M. Yasuda, Bull. Chem. Soc. Jpn., 75, 1577 (2002).
Published on the web (Advance View) May 6, 2003; DOI 10.1246/cl.2003.484