[Cd(O2C(CH2)2CO2)]: An unprecedented 3D hybrid organic-inorganic topology

Article abstract of DOI:10.1016/j.jpcs.2007.10.114

The [Cd(O₂C(CH₂)₂CO₂)] has been hydrothermally prepared and structurally characterized using single-crystal X-ray diffraction. It crystallizes in the monoclinic system, S.G.: I 2/a, a=6.515(2) ?, b=4.889(3) ?, c=30.769(3) ?, β=94.34(8) ?. The structure exhibited alternating infinite chains of edge-sharing CdO₆ octahedra which progress parallel to the a-axis and four corner-sharing CdO₆ octahedra layers which progress in the (a,b) plane, pillared by succinate anion. The topology leads to intersecting hydrophobic channels along (1 1 0) and (1? 1 0) directions. The preparation, structural, thermal and infrared spectroscopic characterizations and ¹¹³Cd NMR (nuclear magnetic resonance) are presented.

Full text of DOI:10.1016/j.jpcs.2007.10.114

ARTICLE IN PRESS
Journal of Physics and Chemistry of Solids 69 (2008) 1419–1421
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[
Cd(O C(CH ) CO )]: An unprecedented 3D hybrid
2 2 2 2
organic–inorganic topology
a,b
a
c
c
A. Seguatni , L.S. Smiri , P.E. Petit , M. Paris , N. Jouini
b,
Ã
a
UR 12/30 Synth e` se et Structure de Mat e´ riaux Inorganiques, Facult e´ des Sciences de Bizerte, 7021 Zarzouna, Tunisia
LPMTM.-UPR-CNRS 9001, Institut Galil e´ e, Universit e´ Paris XIII 99, Avenue J.B. Cl e´ ment 93430, Villetaneuse, France
Institut des Mat e´ riaux Jean Rouxel (IMN) UMR 6502, 2 rue de la Houssini e` re B.P. 32229, 44322 Nantes Cedex 3, France
b
c
Received 30 June 2007; received in revised form 29 September 2007; accepted 30 October 2007
Abstract
The [Cd(O
2
2 2 2
C(CH ) CO )] has been hydrothermally prepared and structurally characterized using single-crystal X-ray diffraction. It
˚
˚
˚
˚
crystallizes in the monoclinic system, S.G.: I 2/a, a ¼ 6.515(2) A, b ¼ 4.889(3) A, c ¼ 30.769(3) A, b ¼ 94.34(8) A. The structure exhibited
alternating infinite chains of edge-sharing CdO octahedra which progress parallel to the a-axis and four corner-sharing CdO octahedra
layers which progress in the (a,b) plane, pillared by succinate anion. The topology leads to intersecting hydrophobic channels along (1 1 0)
6
6
1
13
¯
and (1 1 0) directions. The preparation, structural, thermal and infrared spectroscopic characterizations and
Cd NMR (nuclear
magnetic resonance) are presented.
r 2007 Elsevier Ltd. All rights reserved.
Keywords: A. Microporous materials; C. Infrared spectroscopy; C. Thermogravimetric analysis (TGA); D. Crystal structure; D. Nuclear magnetic
resonance (NMR)
1
. Introduction
layered organic–inorganic metal succinate elaborated by
the hydrothermal method. This compound presents a new
hybrid topology in which 1D and 2D inorganic moieties
exist and are pillared by succinate anions.
There is intense interest today in open-framework
materials due to the numerous high-performance proper-
ties that these materials may present. One can find two
main classes of open-framework materials. The first class
corresponds to the inorganic compounds in which MO6
2. Experimental
octahedra and/or tetrahedral MO share edges or apexes to
4
Infrared spectroscopy, thermal analyses and syntheses
were carried out in the same conditions as in our previous
work [10]. Plate-like colorless crystals of the title com-
pound are obtained starting from CdSO ꢀ 8H O/
form a 3D framework which delimits tunnels and/or
cavities where ions and/or solvent molecules can be
intercalated [1]. The second class corresponds to layered
compounds such as smectite clays [2], a-ZrP phases [3],
titanium-niobium oxide [4], layered double hydroxides [5]
and layered hydroxysalts [6]. Recently, attention has been
drawn to a novel class of open-framework materials
namely organic–inorganic materials [7,8]. In this context,
numerous chemical synthesis routes, mainly ionic exchange
reaction and hydrothermal treatment, have been developed
4
2
HO C(CH ) CO H/KOH/H O (in the molar ratio 1/1/2/
2
2 2
2
2
1
13
330 for 3 days at 180 1C).
Cd MAS-NMR (nuclear
magnetic resonance) spectra were measured on powdered
samples with a Bruker AVANCE 500 MHz spectrometer.
3. Characterization
[
7–9]. We present here the structure features of a new (3D)
The infrared spectrum of [Cd(O C(CH ) CO )] (I) (Fig. 1)
2
2 2
2
shows peaks in three characteristic spectral regions:
ꢁ
1
Ã
1
385–1532 cm should be assigned to n (C–O) and n (C–O)
Corresponding author. Tel.: +33 149 40 34 94; fax: +33 149 40 39 38.
E-mail address: jouini@lpmtm.univ-paris13.fr (N. Jouini).
s
as
of the carboxyl groups. The band at 1385 is split into three
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doi:10.1016/j.jpcs.2007.10.114

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A. Seguatni et al. / Journal of Physics and Chemistry of Solids 69 (2008) 1419–1421
1420
Table 1
Cadmium environment and Cd MAS-NMR chemical shifts
1
13
Compound Cadmium environment
d
(
ppm)
60
8.5
[
Cd(OH)] [O
2
2
C(CH
2
)
2
CO
2
]
Cd(OH-m
edge shared
Cd2(OH-m
edges shared
Cd1(OH-m
edges shared
3 3 3 2 2
) (O-m ) (O-m ) one
[Cd (OH)
3
2
][O C(CH
2
2
)
2
CO
2
]
2
3
)
2
(O-m
3
)
3
2
(O-m
2
2
) two
two
3
)
2
(O-m
3
)
(O-m
)
2
ꢁ19.1
ꢁ71.2
ꢁ84.5
[
Cd(O
2
2
C(CH )
2
2
CO )]
Cd1(O-m
shared
3
)
4
4
(O-m
2
)
)
2
two edges
Cd2(O-m
shared
3
)
(O-m
2
2
four corner
2 2 2 2
Fig. 1. Infrared spectrum of [Cd(O C(CH ) CO )].
2 2 2 2
Fig. 3. Asymmetric unit of [Cd(O C(CH ) CO )].
infinite chains (1D) parallel to the c-axis. The Cd2O6
octahedra share four corners to form layers (2D) which
develop parallel to the (a, b) plane. Both of these parts are
alternately pillared by the carbon atoms of the organic
moiety (Fig. 4). Succinate carbon and carboxyl function
atoms lay in the same medium plane. In addition to its
lamellar character, the framework exhibited intersecting
2 2 2 2
Fig. 2. Thermal analyses of [Cd(O C(CH ) CO )].
components due to the existence of two independent carboxyl
ꢁ
1
groups; 2912–2986 cm , is characteristic of the n(C–H)
vibrational modes. Low-number weaves correspond to
n(C–C) modes [11,12]. The decomposition of (I) is exothermic
and occurs at 700 K in one stage involving the combustion of
the organic moiety and the formation of CdO (theoretical and
¯
channels along (1 1 0) and (1 1 0) directions with almost
2
˚
the same dimension, which is about 7.7 ꢂ 3.6 A (Fig. 4).
In a recent work we have reported on the structures
of [Cd(OH)] [O C(CH ) CO ] (II) and [Cd (OH) ][O C
2
2
2 2
2
3
2
2
113
experimental weight loss: 43.78% and 43.80%) (Fig. 2). Cd
NMR-MAS chemical shifts (Table 1) relative to cadmium
chlorate show a displacement towards negative d depending
on the cadmium coordinated oxygen type.
(CH ) CO ] (III) showing 2D structural topology [10] with
2 2 2 2
open frameworks. They are built up of (2D) inorganic
moieties pillared by succinate anions and present channels,
the dimensions of which are about 7.48 ꢂ 3.61 and
2
˚
8
.08 ꢂ 4.85 A , respectively, for (II) and (III). In addition
4
. Structure description and discussion
to their modulated channels, which can be suitable for
selective non-polar species adsorption [9,13], the three
compounds can be regarded as structural models to
synthesize magnetic materials presenting synergy between
inorganic layers and organic molecules, Cd may be replaced
by Mn, Co, Fe, Ni or Cu and succinate molecules can
be substituted by other carboxylates so as to control
the magnetic interactions through extended polyatomic
ligands, and particularly ligands with conjugated molecules
The asymmetric unit of (I) consists of one succinate
anion and two cadmium atoms which are crystallography
independent (Fig. 3). Both of the cadmium atoms (Cd1 and
Cd2) are octahedrally coordinated by the succinate
oxygens, with Cd–O distances ranging from 2.228 to
˚
˚
2.334 A and from 2.184 to 2.449 A for Cd1 and Cd2,
respectively. The Cd1O octahedra share two edges to form
6

ARTICLE IN PRESS
A. Seguatni et al. / Journal of Physics and Chemistry of Solids 69 (2008) 1419–1421
1421
¯
2 2 2 2
Fig. 4. (1 1 0) view showing channels in [Cd(O C(CH ) CO )].
[14]. The investigation of such hybrid systems is under
progress. Moreover, cadmium is applied as a metallic probe
of Ca(II) and Zn(II) sites, indeed Cd NMR spectroscopy
has been widely used in the study of biological systems
because of its chemical shift sensibility [15,16].
[3] A. Clearfield, Inorg. Ion Mater., CRC Press, Boca Raton Inc.,
Florida, 1982.
[4] H. Rebbah, M.M. Borel, B. Raveau, Mater. Res. Bull. 15 (1980) 317.
1
13
[
[
[
5] F. Cavin, F. Trifiro, A. Vaccari, Catal. Today 11 (1991) 173.
6] L. Poul, N. Jouini, F. Fievet, Chem. Mater. 12 (10) (2000) 3123.
7] M.R. Cavellec, C. Albinet, J.M. Greneche, G. Ferey, J. Mater. Chem.
1 (2001) 3166.
8] H. Li, M. Eddaoudi, M. O’Keeffe, O.M. Yaghi, Nature 402 (1999)
76.
9] K. Barthelet, J. Marrot, D. Riou, G. Fe
1 (2002) 282.
[10] A. Seguatni, M. Fakhfakh, N. Jouini, Solid State Sci. 7 (2005) 1272.
´
1
[
[
5
. Supplementary material
2
´
rey, Angew. Chem. Int. Ed.
Crystallographic data have been deposited with the
Cambridge Crystallographic Data Centre No. CCDC
252286).
4
[
[
11] G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. (1980) 227.
12] K. Nakamoto, Infrared and Raman Spectra of Inorganic and
Coordination Compounds, fourth ed, Wiley, New York, 1986.
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(
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