Synthesis and characterization of the first organically templated layered cerium phosphate fluoride: [(CH2)2(NH3) 2]0.5[CeIVF3(HPO4)]

Article abstract of DOI:10.1246/cl.2004.458

A novel organically templated layered cerium phosphate fluoride [(CH ₂)₂(NH₃)₂]_0.5[Ce ^IVF₃(HPO₄)] has been synthesized by hydrothermal synthesis technology, and characterized by means of single-crystal X-ray diffraction. Its unique layered structure is based on a network of novel CeO₃F₅ polyhedral and PO₄ tetrahedral. The [NH₃(CH₂)₂NH₃]⁺ cations contact with the adjacent layers via hydrogen bonds to compensate the negative charge of the inorganic framework.

Full text of DOI:10.1246/cl.2004.458

458
Chemistry Letters Vol.33, No.4 (2004)
Synthesis and Characterization of the First Organically Templated Layered
Cerium Phosphate Fluoride: [(CH2)2(NH3)2]0:5[CeIVF3(HPO4)]
Ranbo Yu, Dan Wang,yꢀ Shintaro Ishiwata, Takashi Saito, Masaki Azuma, Mikio Takano, Yunfa Chen,y and Jinghai Liy
Institute for Chemical Research, Kyoto University, Kyoto 611-0011
yInstitute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing 100080, P. R. China
(Received January 9, 2004; CL-040041)
A novel organically templated layered cerium phosphate
temperature, so as to stabilize the protonated organic amine and
further incorporate it into the structure of the product. ICP analy-
sis gave the Ce/P ratio of 1.00:1.01, and no S was found in the
product. Elemental analysis indicated that the C, N, and H con-
tents are 3.72%, 4.38%, and 1.91%, corresponding to a molar ra-
tio C:N:H = 1.00:1.01:6.11, which is in good agreement with the
calculated value from the compound formula. Energy dispersive
X-ray spectrometer (EDX) analysis of the compound indicated
the existence of the framework fluoride atoms, and the result
fluoride [(CH2)2(NH3)2]0:5[CeIVF3(HPO4)] has been synthe-
sized by hydrothermal synthesis technology, and characterized
by means of single-crystal X-ray diffraction. Its unique layered
structure is based on a network of novel CeO3F5 polyhedral
and PO4 tetrahedral. The [NH3(CH2)2NH3]þ cations contact
with the adjacent layers via hydrogen bonds to compensate the
negative charge of the inorganic framework.
is coincident with the structure formula [(CH2)2(NH3)2]0:5
[CeIVF3(HPO4)].
A cream color prismatic crystal with approximate dimen-
sions of 0:20 ꢄ 0:20 ꢄ 0:10 mm was selected for single-crystal
X-ray analysis.10 The result indicates that this compound crystal-
lizes in the triclinic system, space group P1 (No. 1) with the cell
-
Lanthanide materials with potential applications as ion ex-
changer, moisture sensor, fluorescence material, and ion conduc-
tor, have attracted considerable research attentions.1 Synthesis of
novel lanthanide materials with layered or open- framework
structures is of great interest because the high coordination num-
bers, variety coordination geometries, and existence of mutable
oxidation states of lanthanide elements would give new materi-
als with novel framework architectures, and some potential
properties such as catalysis, ion exchange, intercalation, and
magnetism as well.2
ꢀ
ꢀ
ꢀ
parameters of a ¼ 6:248ð2Þ A, b ¼ 7:079ð2Þ A, c ¼ 8:794ð3Þ A,
ꢀ ¼ 103:92ð2Þꢃ, ꢁ ¼ 100:84ð2Þꢃ, ꢂ ¼ 110:28ð2Þꢃ, V ¼
ꢀ 3
338:0ð2Þ A , Z ¼ 2.
Hydrothermal methods have proved to be invaluable for the
synthesis of almost all kinds of recently important materials,3 in
particular layered and porous materials with novel structural ar-
chitectures.4 Synthesis of lanthanide materials by using soft
chemistry method including hydrothermal method was stared
early.5 However, these syntheses were limited to some known
phases. In our recent research, by using Fꢁ ion mineralizer
and organic template two novel open-framework cerium materi-
als, cerium oxyfluoride6 and cerium phosphate fluoride,7 and an
organically templated layered cerium phosphate–hydrogen sul-
fate8 have been successfully synthesized under hydrothermal
conditions. Additionally, J. Rocha et al. reported a microporous
cerium silicate.9 In the present work, a novel organically tem-
plated layered cerium phosphate fluoride, [(CH2)2(NH3)2]0:5
-
Figure 1. Stick-and-ball representation of the layer structure
with atoms labeled.
[CeIVF3(HPO4)], has been hydrothermally crystallized. Its
unique layered structure possesses cerium-centered polyhedral
CeO3F5 as a new basic building unit. The protonated ethylene-
diammonium are located between adjacent layers and are con-
nected with them via hydrogen bonds to compensate the nega-
tive charge of the inorganic framework.
The structure of this crystal consists of macroanionic
[CeF3(HPO4)]ꢁ layers and interlamella diprotonated ethylene–
diammonium cations. The macroanionic [CeF3(HPO4)]ꢁ layer
is formed by cerium-centered polyhedral CeO3F5 and phospho-
rus-centered tetrahedral PO4 (Figure 1). The cerium-centered
CeO3F5 polyhedron is a novel basic building unit formed by
the cerium atom coordinated to three oxygen atoms and five flu-
orine atoms, which is different from the other three new cerium-
centered basic building units, CeO6F2,6 CeO4F4,7 CeO9,8 formed
in open-framework and layered structures that we recently re-
ported. Along the b-axis of the structure, CeO3F5 polyhedra
are connected with each other via Ce2F2 rings to give the corru-
gated chains (Figure 2). Each PO4 group shares its oxygen cor-
The title compound was synthesized hydrothermally from a
starting mixture of 1.0 Ce(SO4)2ꢂ2(NH4)2SO4ꢂ4H2O/
3.6H3PO4/2.6 H2N(CH2)2NH2/10 HF/220 H2O. This mixture
was sealed in Teflon-lined stainless steel autoclaves and heated
at 160 ꢃC for 3 days. The cream color crystalline product was fil-
tered and washed with deionized water, and then dried in air at
ambient temperature. As the acidity of the reaction system is al-
ways the dominant factor for product crystallization, in this syn-
thesis we tried to use a relatively high acidity and low synthesis
Copyright Ó 2004 The Chemical Society of Japan

Chemistry Letters Vol.33, No.4 (2004)
459
ners with three CeO3F5 polyhedra and leave the forth oxygen as
–OH group to link up the chains of cerium-centered polyhedra
and form the 2-D layers (Figure 1). The macroanionic layers
were separated by organic diprotonated ethylenediaminum cati-
ons. In the planes vertical to the c-axis, there is six-ring window
contains four CeO3F5 polyhedra and two PO4 tetrahedra with the
polyhedron arrangement as –Ce–Ce–P–Ce–Ce–P– and has diag-
layered or open-framework materials with wide topological
range based on novel units. By proper controlling of organic
templates and reaction conditions the syntheses of other novel
lanthanide materials are very possible. Moreover, with
[(CH2)2(NH3)2]2þ cations located in the interspace of the layers,
the title compound might have interesting ion-exchange proper-
ties.
ꢀ
onal varied between 3.86 and 7.08 A (Figure 1), which is similar
to that of six-ring channels of (NH4)[CeIVF2(PO4)].7 Ethylene-
diaminium cations are located near the six-ring windows to bal-
ance the framework negative charge and direct the windows
structure.
References and Notes
1
2
3
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Mater., 11, 2008 (1999); D. Wang, R. Yu, S. Feng, W. Zheng,
R. Xu, N. Kumada, and N. Kinomura, Mater. Res. Bull., 36,
239 (2001); D. Wang, R. Yu, S. Feng, W. Zheng, R. Xu, Y.
Matsumura, and M. Takano, Chem. Lett., 32, 74 (2003).
D. Wang, R. Yu, N. Kumada, and N. Kinomura, Chem.
Mater., 12, 956 (2000); D. Wang, R. Yu, T. Takei, N.
Kumada, N. Kinomura, A. Onda, K. Kajiyoshi, and K.
Yanagisawa, Chem. Lett., 2002, 398; D. Wang, R. Yu, N.
Kumada, N. Kinomura, K. Yanagisawa, Y. Matsumura, and
T. Yashima, Chem. Lett., 2002, 804.
R. Mooney, Acta Crystallogr., 3, 337 (1950); M. Vlasse, Acta
Crystallogr., 38, 2328 (1982); G. Wu, M. Jansen, and K.
Konigsten, J. Solid State Chem., 98, 210 (1992); Y. Xu, S.
Feng, W. Pang, and G. Pang, Chem. Commun., 1996, 1305.
R. Yu, D. Wang, N. Kumada, and N. Kinomura, Chem.
Mater., 12, 3527 (2000).
4
5
6
7
8
9
Figure 2. Stick-and-ball representation of the title compound
showing arrangement of organic template between the adjacent
layers.
R. Yu, D. Wang, T. Takei, N. Kumada, and N. Kinomura, J.
Solid State Chem., 157, 180 (2001).
D. Wang, R. Yu, S. Feng Y. Xu, N. Kumada, N. Kinomura, Y.
Matsmura, and M. Takano, Chem. Lett., 2002, 1120.
J. Rocha, P. Ferreira, L. D. Carlos, and A. Ferreira, Angew.
Chem., Int. Ed. Engl., 39, 3276 (2000).
ꢀ
The Ce–O distances vary in the range from 2.208 to 2.35 A,
ꢀ
which is comparable with the range of 2.188–2.407 A for cerium
atoms coordinated by eight oxygen atoms in CeIVOSO4(H2O).11
ꢀ
The average Ce–F bond length of 2.300 A is coincident with that
10 All measurements were made on a Rigaku RAXIS imaging
plate area detector with graphite monochromated Mo Kꢀ radi-
ation. The space group was determined to be P1 (No. 1). Of
the 10144 reflections which were collected, 5072 were unique;
equivalent reflections were merged. The structure was solved
by direct methods and expanded using Fourier techniques.
The non-hydrogen atoms were refined anisotropically. The fi-
nal cycle of full-matrix least-squares refinement on F was
based on 4566 observed reflections (I > 3:00ꢃðIÞ) and 199
variable parameters and converged (largest parameter shift
was 0.02 times its esd) with unweighted and weighted agree-
ment factors of R ¼ 0:024, Rw ¼ 0:021. Crystallographic data
reported in this paper have been deposited with Cambridge
Crystallographic Data Centre as supplementary publication
no. CCDC-227968. Copies of the data can be obtained free
of charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or
from the Cambridge Crystallographic Data Centre, 12, Union
Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033; or
deposit@ccdc.cam.ac.uk).
observed in NH4CeF7(H2O).12 The average P–O distance of
ꢀ
ꢀ
1.537 A is a little longer than 1.53 A observed in calcium–cerium
phosphate, Ca19CeIV(PO4)14.13 The organic template is connect-
ed with the inorganic layers through hydrogen bonds. N(1) and
N(2) are involved in hydrogen bonds with framework terminal
ꢀ
F(4) and F(5) with N(1)ꢅF(5) = 2.934(3) A and N(2)ꢅF(4) =
ꢀ
2.909(3) A, respectively.
Differential thermal analysis and thermogravimetric analy-
sis of this compound shows that the template ethylenediamine
decomposed endothermically at 265 ꢃC, which gives rise to a
marked weight loss. Then the title compound undergoes compli-
cated oxidization decomposition at 300–800 ꢃC and converts in-
to a crystalline phase of CePO4 at higher temperature.14 The total
weight loss is ca. 27.14% which agrees well with the calculated
result (27.46%) according to Eq 1:
[(CH2)2(NH3)2]0:5[CeIVF3(HPO4)] þ 1.25O2 !
CO2" þ NH3" þ 1.5F2" þ 0.5H2O" þ CePO4
ð1Þ
11 O. Lindgren, Acta Crystallogr., Sect. B, 32, 3347 (1976).
12 R. Ryan and R. Penneman, Acta Crystallogr., Sect. B, 27,
1939 (1971).
13 B. Lazoryak, R. Kotov, and S. Khasanov, Zh. Neorg. Khim.,
41, 1281 (1996).
In summary, a novel organically templated layered cerium
phosphate fluoride has been synthesized under hydrothermal
conditions. This work indicates that the higher acidity of the syn-
thesis system might be a dominant factor that influences the in-
corporation of organic amine template into the structure, and fur-
ther reveals the possibility of formation of organically templated
14 ‘‘Powder Diffraction File, Inorganic and Organic, Set 32, 32-
199,’’ JCSPD International Center Diffraction Data, U.S.A.
Published on the web (Advance View) March 20, 2004; DOI 10.1246/cl.2004.458