Novel supramolecular cpmpounds with three-dimensional hydrogen-bonded network [M(H2O)6][H2L] (H4L = 1,2,4,5-benzenetetracarboxylic acid, M = MnII and CoII): Syntheses, characterization and

Article abstract of DOI:10.1016/S0022-2860(02)00046-7

Two hydrogen-bonded supermolecular compounds having the general have been newly prepared by the reaction of [M(H₂O)₆](ClO₄)₂ and [C₆H₂(COOH)₄] (H₄L), and structurally

Full text of DOI:10.1016/S0022-2860(02)00046-7

Journal of Molecular Structure 610 (2002) 191±196
www.elsevier.com/locate/molstruc
Novel supramolecular compounds with three-dimensional
hydrogen-bonded network [M(H2O)6][H2L](H L ˆ 1,2,4,5-
4
benzenetetracarboxylic acid, M ˆ MnII and CoII): syntheses,
characterization and crystal structures
a,
Li-Ya Wang , Yu Zhu , Chen-Xia Du , Huai-Bo Ma
b
b
a
*
aDepartment of Chemistry, Luoyang Teacher's College, Luoyang 471022, People's Republic of China
bDepartment of Chemistry, Zhengzhou University, Zhengzhou 450001, People's Republic of China
Received 14 December 2001; accepted 15 January 2002
Abstract
Two hydrogen-bonded supramolecular compounds having the general formula [M(H2O)6][H2L](M ˆ MnII or CoII and
H4L ˆ 1,2,4,5-benzenetetracarboxylic acid), have been newly prepared by the reaction of [M(H2O)6](ClO4)2 and
[C6H2(COOH)4](H 4L), and structurally characterized by X-ray diffraction. The metal center in each compound is six-coordi-
nated, forming an ideal octahedral geometry. Both neutral formula units make unique three-dimensional supramolecular
architectures through hydrogen bonds and stabilized by electrostatic force. q 2002 Elsevier Science B.V. All rights reserved.
Keywords: MnII and CoII compounds; Crystal structures; Hydrogen bonds; Supramolecular compounds; Three-dimensional network
1. Introduction
design for the preparation of molecular materials
with controlled physical and chemistry properties
[4,5]. The interactions of hydrogen bonds also play
vital roles for molecular recognition in a wide variety
of biological systems [6]and crystal packing in crys-
tallography [7], and some important results have been
reviewed [3,5,8].
Polycarboxylic acids and their transition metal
complexes have been extensively investigated on
coordination and/or covalent crystal engineering, in
which the metal atoms participate in the bonding
either directly or as ancillary systems [9±15].
Normally, this type of supramolecular structure has
been constructed by hydrogen-bonding and coordina-
tion interactions co-effect. In the present work, we
report the preparation and crystal structures of two
The self-assembly of metal compounds into one-,
two- and three-dimensional supramolecular architec-
tures is currently attracting considerable attention for
potential applications because the macroscopic
physical properties of crystals are de®ned by the inter-
molecular electronic interactions presented in the
solid state [1±3]. Consequently, there is a need for
the development of highly directional intermolecular
interactions, which are able to generate predetermined
molecular arrangement. The high directionality of
hydrogen bonds makes them useful in crystalline
* Corresponding author. Fax: 186-379-5511205.
E-mail address: liyawang@eyou.com (L.-Y. Wang).
0022-2860/02/$ - see front matter q 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-2860(02)00046-7

192
L.-Y. Wang et al. / Journal of Molecular Structure 610 (2002) 191±196
Table 1
Crystallographic data and structure re®nement summary for compounds 1 and 2
1
2
Formula
Molecular weight
Color
C10H16MnO14
415.17
C10H16CoO14
419.16
Light-yellow
Monoclinic
C2/c
Purple
Crystal system
Space group
Unit cell dimensions (A, 8)
Monoclinic
C2/c
Ê
a ˆ 22:277ꢀ11†
b ˆ 9:839ꢀ5†
c ˆ 7:422ꢀ4†
b ˆ 105:524ꢀ8†
1567.4(14)
4
a ˆ 22:070ꢀ4†
b ˆ 9:806ꢀ2†
c ˆ 7:3199ꢀ15†
b ˆ 105:41ꢀ3†
1527.3(5)
4
Ê 3
Volume (A )
Z
Dcalcd (g/cm3)
1.759
9.19
1.823
12.01
m (cm21
F(000)
)
852
860
Crystal size (mm)
Range of h, k, l
0.30 £ 0.25 £ 0.20
223/26, 29/11, 28/7
3168/1386
136
0.40 £ 0.35 £ 0.20
228/28, 212/0, 29/9
2738/1569
148
Re¯ections collected/unique
Parameters
R and Rw
Residual electron densities
0.0359, 0.0906
0.506 to 20.458
0.0287, 0.0687
0.314 to 20.342
Ê 3
(e/A )
Goodness of ®t
1.037
1.107
novel three-dimensional supramolecular compounds
[Mn(H2O)6][H2L]( 1) and [Co(H2O)6][H2L]( 2),
directly self-assembled by [M(H2O)6]21 and 1,2,4,5-
benzenetetracarboxylic acid (H4L). It is interesting
that in both complexes hydrogen-bonding and electro-
static force interactions have been found between the
[M(H2O)6]21 and H2L22 on which the supramolecular
architectures depend.
2.2. Syntheses of the compounds
Compounds 1 and 2 were prepared by mixing 1:1
molar ratio of [M(H2O)6](ClO4)2 (M ˆ MnII and CoII)
and H4L in methanol/water. The mixture was heated
to ,60 8C with stirring for 1 h, then ®ltered and left to
stand at room temperature. Well-shaped crystals
suitable for X-ray analyses were obtained by slow
evaporation of the solvent in ca. 70±80% yields
within a week. Elemental analyses results are in
good agreement with the stoichiometries. Found (1):
C, 28.69; H, 3.76; calculated for C10H16MnO14: C,
28.93; H, 3.88. Found (2): C, 28.51; H, 3.96; calcu-
lated for C10H16CoO14: C, 28.65; H, 3.85.
2. Experimental
2.1. Materials and general methods
All reagents for syntheses and analyses were of
analytical grade and hydrated metal perchlorates
were prepared by standard method. FT-IR spectra
(KBr pellets) were taken on a FT-IR 170SX (Nicolet)
spectrometer and elemental analyses were performed
on a Perkin±Elmer 240C analyzer. Thermal stability
(TG-DTA) studies were carried out on a Dupont
thermal analyzer from room temperature to 800 8C
under a helium atmosphere.
2.3. X-ray crystallographic studies of compounds 1
and 2
Single-crystal X-ray diffraction measurements
were carried out with a BRUKER SMART 1000
CCD diffractometer equipped with a graphite mono-
chromator for data collection at room temperature.
The determination of the unit cell parameters and

L.-Y. Wang et al. / Journal of Molecular Structure 610 (2002) 191±196
193
Table 2
Atomic coordinates and equivalent isotropic displacement para-
Table 4
Selected bond lengths (A) and angles (8) for compounds 1 and 2
Ê
meters for compound 1
1
2
Atom
x
y
z
Ueq
M±O(5)
M±O(6)
2.14(4)
2.22(3)
2.17(2)
2.20(4)
1.23(4)
1.29(4)
1.28(4)
1.24(4)
87.3(8)
2.129(2)
2.085(2)
2.121(2)
2.070(2)
1.238(2)
1.287(7)
1.278(2)
1.243(2)
86.64(4)
Mn(1)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
C(1)
C(2)
C(3)
C(4)
C(5)
0.5000
0.2015(8)
0.998(3)
1.124(3)
0.411(3)
0.577(3)
0.419(4)
0.187(3)
0.212(3)
0.2500
0.021(3)
0.028(6)
0.032(6)
0.041(7)
0.032(6)
0.040(10)
0.025(6)
0.033(7)
0.033(9)
0.021(8)
0.017(7)
0.017(7)
0.018(7)
0.022(8)
0.3514(10)
0.2771(11)
0.3312(11)
0.3994(10)
0.5000
0.296(3)
0.121(4)
0.043(4)
0.066(4)
0.2500
M±O(7)
M±O(8)
O(1)±C(1)
O(2)±C(1)
O(3)±C(5)
0.5602(11)
0.4163(12)
0.5000
0.055(3)
0.020(4)
0.2500
O(4)±C(5)
O(5)±M±O(7)
O(7)±M±O(7A)
O(5)±M±O(8)
O(7)±M±O(8)
O(5)±M±O(6)
O(7)±M±O(6A)
O(7)±M±O(6)
O(8)±M±O(6)
O(6)±M±O(6A)
20.022(4)
1.007(4)
0.878(3)
0.768(3)
0.641(3)
0.537(4)
174.7(16)
180.0(4)
92.7(8)
173.28(8)
180.0(1)
93.36(4)
92.68(5)
89.59(6)
90.72(6)
87.32(5)
174.63(10)
0.3017(15)
0.2706(15)
0.3110(14)
0.2930(15)
0.3450(15)
0.175(4)
0.082(4)
0.092(4)
0.013(4)
0.040(5)
93.6(7)
88.5(10)
91.9(10)
86.4(7)
172.8(15)
data collections were performed with Mo Ka
ꢀ
radiation ꢀl ˆ 0:71073 A† and unit cell dimensions
Most of the hydrogen atoms were also located in
successive difference Fourier syntheses (H(8F) and
H(3A) atoms in compound 1 were added theoretically
onto the parent atoms and re®ned with ®xed thermal
factors) and take in the re®nement. Further details of
the structural analyses are given in Table 1. Positional
parameters and atomic coordinates are given in Tables
2 and 3, whereas selected bond distances and angles
are listed in Table 4.
were obtained with least-squares re®nements. The
structures were solved by direct methods and
semi-empirical absorption corrections (SADABS)
were applied. MnII and CoII atoms in the corre-
sponding complexes were located from E-maps and
all the other non-hydrogen atoms were located in
successive difference Fourier syntheses. The ®nal
re®nement was carried out by full matrix least-squares
methods with anisotropic thermal parameters on F2.
Table 3
3. Results and discussion
Atomic coordinates and equivalent isotropic displacement para-
meters for compound 2
The IR spectra reveal the presence of a large
number of different hydrogen bonding between 3000
and 3500 cm21 with the strongest peaks at 3227 cm21
for 1 (3229 cm21 for 2) which can be ascribed to the
O±H stretching. The strong band at 1692 and
1676 cm21 for 1 (1698 and 1679 cm21 for 2), and
1360 and 1345 cm21 for 1 (1358 and 1341 cm21 for
2) are observed, which is due to the asymmetry and
symmetry COOH/COO2 stretching of H2L22. Both
complexes are air stable at room temperature,
however, decomposition occurred at elevated
temperature. The coordination water content of both
complexes has been veri®ed by TGA in 25±800 8C
Atom
x
y
z
Ueq
Co(1) 0.5000
1.20036(3)
0.2500
0.01756(14)
C(1)
C(2)
C(3)
C(4)
C(5)
O(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
0.30249(8) 20.00839(18)
0.6738(3) 0.0183(4)
0.5829(3) 0.0161(4)
0.5915(3) 0.0173(4)
0.5118(2) 0.0160(4)
0.5392(3) 0.0200(4)
0.7971(2) 0.0269(3)
0.6177(2) 0.0287(3)
0.5430(3) 0.0369(4)
0.5647(2) 0.0299(4)
0.27093(8)
0.31183(9)
0.29334(8)
0.34590(9)
0.35311(6)
0.12166(17)
0.23158(18)
0.35954(17)
0.46432(18)
0.00000(14)
0.27773(7) 20.12502(13)
0.33220(7)
0.40081(6)
0.5000
0.59075(14)
0.42326(14)
0.9832(2)
0.2500
0.0291(5)
0.58035(7)
0.44235(7)
0.5000
1.21032(17)
1.18768(14)
1.4114(2)
0.4769(2) 0.0284(4)
0.4396(2) 0.0221(3)
range under a helium atmosphere. For both
compounds, the ®rst loss of 25.73% for 1 (26.02%
0.2500
0.0344(6)

194
L.-Y. Wang et al. / Journal of Molecular Structure 610 (2002) 191±196
Fig. 1. ORTEP structure of [Mn(H2O)6][H2L]showing the intramolecular hydrogen bonds with 30% thermal ellipsoid probability.
for 2), from 105 to 130 8C, corresponds to six water
molecules (calculated 26.01 and 25.76%, respec-
tively) coordinatively bonded to the metal ion.
Upon further heating, a second weight loss from
175 to 215 8C is observed, which is due to the loss
of part of benzenetertracarboxylic acid. The ®nal
process is accompanied by the decomposition of
the benzenetertracarboxylic acid at above 320 8C,
ultimately giving the ®nal solid product to be
Mn2O3 or Co2O3.
The X-ray crystal structures of 1 and 2 show that
they are isomorphous (see Table 1) and isostructural.
As seen in Fig. 1, the neutral compounds consist of
one [M(H2O)6]21 cation and a H2L22 anion (the MnII
complex 1 is shown as an example). In the
[M(H2O)6]21 cation, there are six water molecules in
the coordination sphere of each metal center which
has an ideal octahedral geometry. Four independent
M±O bond lengths are almost equal to each other in
each compound, and the corresponding distances in 1
are slightly longer than those in 2. Each metal center is
constrained to lie on the least-squares plane de®ned by
O(6), O(6A), O(7) and O(7A), which deviates by only
M±O(8) bond angle is almost linear, which can be
de®ned as the apex of the octahedron.
There exists a intramolecular O±H´´´O hydrogen
bond between the O(2A) and O(3) atoms of the
ortho-positioned carboxy and carboxylate groups in
each H2L22 anion as shown in Fig. 1. Other two intra-
molecular hydrogen bonds (O(3)´´´O(7) and
O(4)´´´O(5)) were also found to link the [M(H2O)6]21
cation and the H2L22 anion (Fig. 1). For [M(H2O)6]21
cations, they were interlinked through two intermole-
cular hydrogen bonds (O(6)´´´O(5) and O(6A)´´´O(8))
to form a one-dimensional chain arrangement along c-
direction as shown in Fig. 2(a). However, no weak
interaction such as hydrogen bonds or p´´´p stacking
was found to exist among the H2L22 anions as shown in
Fig. 2(b). Further, each [M(H2O)6]21 cation links eight
H2L22 anions around it though intramolecular O´´´O
hydrogen bonds as shown in Fig. 2(c). Therefore, the
hydrogen bonds interlink the adjacent compound units
to form the three-dimensional network architecture as
shown in Fig. 3. The O´´´O separations are in 2.720±
Ê
Ê
2.819 A for 1 range (2.695±2.838 A for 2) with the
bond angles in 152.7±171.48 range for 1 (168.5±
179.68 for 2), all being in the normal range of weak
interactions. Indeed the supramolecular structure
Ê
ca. 0.02 A from this plane. The sum of the bond angles
within the plane is very close to 3608 and the O(5)±

L.-Y. Wang et al. / Journal of Molecular Structure 610 (2002) 191±196
195
Fig. 3. Three-dimensional hydrogen bonding network supramole-
cular structure of [Mn(H2O)6][H2L]along (a) xz (b) yz plane.
Fig. 2. (a) Linear arrangement of [Mn(H2O)6]21 cations along c-
direction linked through intermolecular hydrogen bonds. (b) The
arrangement of H2L22 in (1 1 0) plane. (c) H2L22 anions
surrounding one [Mn(H2O)6]21 cation linkage of intermolecular
hydrogen bonds.
In conclusion, the title supramolecular compounds
can be assembled by means of the direct reaction
between [M(H2O)6]21 and H4L. Both compounds
exhibit the similar three-dimensional hydrogen-
bonded network structure. It will provide the inter-
esting experimental data for the supramolecular
chemistry and crystal engineering.
depends on two kinds of interactions: the hydrogen
bonding and the electrostatic force. The electronic
charge of ions decides the ratio of the two units of
the cation and anion in the compound system. The
binding force mainly comes from the electrostatic
interaction between the two building blocks and the
hydrogen bonding leads to the orientation and
selectivity in the binding of the two units. The corpo-
rate effects of the two kinds of interactions make the
crystal structures more stable.
4. Supplementary materials
Crystallographic data for the structures reported in
this paper have been deposited with the Cambridge
Crystallographic Data Center as supplementary mate-
rials (no. CCDC-168720 and 168721). Copies of

196
L.-Y. Wang et al. / Journal of Molecular Structure 610 (2002) 191±196
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e-mail: deposit@ccdc.cam.ac.uk).
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