Synthesis, crystal structure and thermal decomposition of solid complex

Article abstract of DOI:10.1023/B:JTAN.0000027815.73030.29

New solid complex of nitrilotriacetic acid and bismuth trichloride was synthesized by a solid phase reaction of nitrilotriacetic acid and bismuth trichloride at room temperature. The composition of the sample is BiCl ₃[N(CH₂COOH)₃]_2.5. The crystal structure of the complex belongs to triclinic system with the lattice parameters: a=0.7849 nm, b=0.9821 nm, c=2.0021 nm, α=96.50°, β=98.76° and y=90.49°. The far-infrared spectra show the bonding between the Bi ion and N atom of nitrilotriacetic acid. The thermal analysis also demonstrates the complex formation between the bismuth ion and nitrilotriacetic acid. The gaseous pyrolysis product and the final residue in the thermal decomposition process are determined to check the thermal decomposition reaction.

Full text of DOI:10.1023/B:JTAN.0000027815.73030.29

Journal of Thermal Analysis and Calorimetry, Vol. 76 (2004) 157–163
SYNTHESIS, CRYSTAL STRUCTURE AND THERMAL
DECOMPOSITION OF SOLID COMPLEX
*
R. R. Jia, Y. X. Yang, Y. R. Chen and Y. Q. Jia
Department of Chemistry, East China University of Science and Technology, Shanghai 200237,
P. R. China
(
Received July 10, 2003; in revised form October 28, 2003)
Abstract
New solid complex of nitrilotriacetic acid and bismuth trichloride was synthesized by a solid phase reac-
tion of nitrilotriacetic acid and bismuth trichloride at room temperature. The composition of the sample is
3 2 3
BiCl [N(CH COOH) ]2.5. The crystal structure of the complex belongs to triclinic system with the lattice
parameters: a=0.7849 nm, b=0.9821 nm, c=2.0021 nm, α=96.50°, β=98.76° and γ=90.49°. The far-infra-
red spectra show the bonding between the Bi ion and N atom of nitrilotriacetic acid. The thermal analysis
also demonstrates the complex formation between the bismuth ion and nitrilotriacetic acid. The gaseous
pyrolysis product and the final residue in the thermal decomposition process are determined to check the
thermal decomposition reaction.
Keywords: crystal structure, nitrilotriacetic acid complex of bismuth, solid phase synthesis,
thermal decomposition
Introduction
The main group elements, such as antimony and bismuth, can possess a certain bio-
logic or medicinal properties [1–6] and some complexes of the antimony and bismuth
can also treat the cancer [7, 8]. Therefore, to synthesize the new complexes of the bis-
muth ion and various organic ligands is very interesting not only for the main group
element chemistry, but also for the bioinorganic and pharmaceutical chemistry.
To synthesize the solid complexes of the organic ligands and bismuth ion by the
aqueous solution reaction is rather difficult, because the inorganic salts of the bis-
muth ion are very easily hydrolyzed in the aqueous solution [9]. The solid–solid reac-
tion is a simple synthesis method. However, the solid–solid reactions are often car-
ried out at high temperature. We have found that some inorganic salts of bismuth ion
and some organic ligands can also react very easily at room temperature. We synthe-
sized some new solid complexes of antimony(III) and bismuth(III) by the solid–solid
reaction at room temperature [10]. Here, we shall report the solid–solid reaction syn-
*
Author for correspondence: E-mail: yqjiac@online.sh.cn
1
388–6150/2004/ $ 20.00
Akadémiai Kiadó, Budapest
©
2004 Akadémiai Kiadó, Budapest
Kluwer Academic Publishers, Dordrecht

1
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JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
thesis process of a new solid complex of nitrilotriacetic acid and bismuth trichloride,
the crystal structure, far-infrared spectra and thermal decomposition of the complex.
Experimental
All the chemicals used in the experiments are analytical reagent. First, to weigh
0.942 g (3.0 mmol) BiCl and 1.439 g (7.5 mmol) N(CH COOH) and very well to mix
up the two reactants together. The molar ratio of BiCl to N(CH COOH) was 1:2.5.
3
2
3
3
2
3
Carefully to grind the mixture in an agate mortar. At first the mixture became slightly
viscous, then, gradually became a white loose powder. This indicated that the reaction
did happen. The reaction conducted in grinding at room temperature for about 8 h. In the
end, the resultant was dried in a vacuum drying oven. The resultant is polycrystalline and
shows slightly moisture in air.
Carbon, hydrogen and nitrogen in the resultant were determined by an Elementar
Vario EL elemental analysis. The content of bismuth in the resultant was measured by
the EDTA titration method. The relative content of the element: C (theor. 22.71%;
found 23.8%), H (theor. 2.86%; found 3.00%), N (theor. 4.40%; found 4.56%) and
Bi (theor. 26.35%; found 25.94%), respectively. The element analyses yield the com-
position BiCl ⋅C15H N O15 of the resultant.
3 22.5 2.5
The powder X-ray diffraction pattern of the resultant was recorded by a D/max-YB
–1
X-ray diffractometer, CuK radiation, scanning rate 2°(2θ) min , at room temperature.
α1
The results of indexing to the X-ray diffraction pattern are listed in Table 1. The
far-infrared spectra of the resultant and nitrilotriacetic acid were measured by a Nicolet
5D-FT spectrometer and the cesium iodide disk technique. The far-infrared spectra of the
–1
resultant and nitrilotriacetic acid in the region from 50 to 650 cm are shown in Fig. 1.
The thermal decomposition process of the resultant was studied by a LCT-1 differential
–1
thermal balance in air, with a heating rate of 10°C min and α-Al O reference. The
2
3
thermogravimetric and differential thermal analysis curves of the resultant are shown in
Fig. 2. The possible pyrolysis reactions, experimental and calculated percentage mass
losses in the thermal decomposition process for the resultant are summarized in Table 2.
Results and discussion
All the diffraction peaks in the pattern can be readily indexed by a set of lattice para-
meters according to triclinic system, although the number of the diffraction peaks is
more. As Table 1 shows, the largest relative deviation between the calculated and
experimental dhkl is also less than 0.3%. This indicates that the product of the reaction is a
single phase compound with triclinic symmetry. The crystal structure of bismuth tri-
chloride belongs to orthorhombic system (JCPDS 24-1003) and of nitrilotriacetic acid
belongs to monoclinic system (JCPDS 44-1941). The crystal structure of the resultant
belongs neither to orthorhombic nor to monoclinic system, but to triclinic system.
Obviously, the resultant must be a new complex with the triclinic symmetry and the
J. Therm. Anal. Cal., 76, 2004

JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
159
J. Therm. Anal. Cal., 76, 2004

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JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
formula BiCl [N(CH COOH) ] . However, we have also found that the complex with
3
2
3 2.5
the composition BiCl :N(CH COOH) =1:2 can not be obtained by same method.
3
2
3
Table 2 Thermal decomposition data of BiCl
3
[N(CH
2
3 2.5
COOH) ]
Mass loss/%
Reaction
T/°C
W
exp
W
theor
BiCl
¯
3 2 3 2.5
[N(CH COOH) ]
–3HCl
2
36 (endo)
14.1
37.7
7.3
13.8
36.2
7.3
BiN(CH
¯
2
3 2 3 1.5
COO) [N(CH COOH) ]
2
65 (exo)
–1.5N(CH
2
COOH)
3
BiN(CH COO)
–CH COO
2
3
4
17 (exo)
¯
2
2
BiN(CH COO)
2
¯
¯
¯
¯
–0.5[OOCH
2
CNCH
2
C–O–CH
2
CNCH
2
COO]
521 (exo)
11.1
13.3
Bi
2
O
3
29.8*
29.4**
*
*
The percentage mass of the residue in the sample
*The percentage content of Bi in the sample
2
O
3
The absorption peaks from the vibrations of the chemical bonds between the heavy
metal ion and the organic ligands are in the far-infrared region. Figure 1 shows that the
far-infrared spectra of the complex and nitrilotriacetic acid are very similar, except that
–1
there is a new absorption peak at 521 cm in the far-infrared spectrum of the complex.
–1
The absorption peak from the stretching vibration of the Bi–N bond is at 497 cm and of
–1
the Bi–O bond is at 443 cm in the complex of hexamethylenetetramine and bismuth
–1
ion, respectively [10]. The frequency (521 cm ) of the new absorption peak in the far-in-
–1
frared spectrum of the complex is closer to that (497 cm ) of the stretching vibration of
–1
the Bi–N bond. Therefore, we can assign the new absorption peak at 521 cm probably
to the stretching vibration of the chemical bond between the bismuth ion and nitrogen
atom of the nitrilotriacetic acid. In the far-infrared spectrum of the gaseous bismuth
–1
trichloride molecule, there are 4 characteristic absorption peaks: u =342 cm and
1
–1
u =322 cm from the symmetric and asymmetric stretching vibration of the Bi–Cl bond,
3
–1
–1
u =123 cm and u =107 cm from the symmetric and asymmetric deformation vibration
2
4
of the Cl–Bi–Cl bond, respectively [11]. However, the 4 characteristic absorption peaks
of the bismuth trichloride molecule do not appear in the far-infrared spectrum of the
complex. Of course, we can not rule out that the 4 characteristic absorption peaks and
some characteristic absorption peaks of the nitrilotriacetic acid may overlap each other in
the far-infrared spectrum of the complex. But, if this does so, some absorption peaks in
the far-infrared spectrum of the complex must become appreciable wider than the corre-
sponding absorption peaks in the far-infrared spectrum of the nitrilotriacetic acid or some
new shoulders near the main absorption peaks in the far-infrared spectrum of the com-
J. Therm. Anal. Cal., 76, 2004

JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
161
2 3 3 2 3 2.5
Fig. 1 The far-infrared spectra of a – N(CH COOH) and b – BiCl [N(CH COOH) ]
plex should appear, because the position of the 4 characteristic absorption peaks of the
bismuth trichloride molecule are different from the position of the characteristic absorp-
tion peaks of the nitrilotriacetic acid in the infrared spectra. However, as Fig. 1 shows,
the shapes and widths of all the absorption peaks in the far-infrared spectrum of the com-
plex are very similar to those in the fra-infrared spectrum of the nitrilotriacetic acid. So, it
is possible that there are no Bi–Cl bonds in the complex or the bonding between the bis-
muth ion and chloride anion in the complex becomes rather weak. Besides, we have also
noted that no absorption peak from the vibration of the Bi–O bond can be found in the
far-infrared spectrum of the complex. This means the absence of the bonding between
the bismuth(III) and the oxygen atoms of the carboxylic group of the nitrilotriacetic acid.
If the above conclusions are reasonable, the far-infrared spectra indicate that the bismuth
ion is coordinated neither to the chlorine atoms nor to the oxygen atoms, but only to the
nitrogen atoms of the nitrilotriacetic acid in the complex.
J. Therm. Anal. Cal., 76, 2004

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JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
Figure 2 shows that the first mass loss of the sample begins at about 230°C. The
experimental mass loss (14.1%) indicates the losing of 3HCl molecules (the calculated
percentage mass loss: 13.8%). The elimination of the HCl molecules from the complex
needs certain energy. Therefore, there is a considerable endothermic peak at about 236°C
in DTA curve. To check if the pyrolysis product is the hydrogen chloride gas, a certain
amount (about 50 mg) of the complex is placed in a glass test-tube and is slightly heated.
The quality of the gaseous decomposition product is detected by using a wet pH paper
and a wet paper containing AgNO . The test demonstrates that the pyrolysis product is an
3
acid gas, while its reaction with AgNO gives AgCl. The fact that all the chlorine atoms
3
are very easily eliminated from the complex at such a low temperature, as 230°C, may
refer to uncoordinated chlorine anions in the complex. This observation may also support
the conclusion of the far-infrared spectrum of the compound. Namely, that there are no
Bi–Cl bond vibration peaks in the far-infrared spectrum of the complex. The second
mass loss of the sample occurs at about 265°C and there is a small exothermic peak in
DTA curve. It is due to the elimination of 1.5 moles of the neutral ligands from the
complex. The experimental mass loss (about 38%) is close to the calculated one (36.1%).
In the thermal decomposition process, the reaction of the pyrolysis products and the
oxygen in air leads to an exothermic peak in DTA curve. The loss of the neutral
nitrilotriacetic acids from the complex seems to show that the oxygen atoms of the
carboxyl groups of the nitrilotriacetic acids are not bonded directly to the bismuth ion. In
that case the sample would gradually lose the CH COO groups with increasing
2
temperature. The experimental mass loss for the elimination of the CH COO group
2
agrees with the calculated value (7.3%). The elimination of the uncoordinated CH COO
2
group from the N(CH COO) is conducted more easily than that of the N atom from the
2
3
N(CH COO) group. This experimental observation supports the proposition that the
2
3
nitrogen atom of the N(CH COO) group, and not the oxygen atom of the N(CH COO)
3
2
3
2
3 2 3 2.5
Fig. 2 TG and DTA curves of BiCl [N(CH COOH) ]
J. Therm. Anal. Cal., 76, 2004

JIA et al.: NITRILOTRIACETIC ACID COMPLEX OF BISMUTH
163
group, is coordinated directly to the bismuth ion. This also corresponds with the
far-infrared spectrum of the complex. Namely, in the spectrum of the compound only the
absorption peak from the Bi–N vibration is detected, but that from the Bi–O vibration is
not present. When the temperature becomes higher, structural rearrangement between the
atoms in the residual sample may take place and probably the Bi(III) shall bond to the
oxygen atoms of the residual ligand. When the temperature is above 500°C, at first the
residue loses two CH COO groups, then, it loses the NCH COCH CN group. Both the
2 2 2
CH COO and NCH COCH CN groups can react with the oxygen in air. This is just why
2
2
2
two exothermic peaks appear continuously in DTA curve. Finally, the end product of the
pyrolysis is Bi O . To check the final residue, a certain amount of the complex is placed
2
3
in an alumina crucible and is heated gradually from room temperature to 500°C in a
muffule furnace. Then, the sample is kept for 5 min at 520°C. The chemical analysis of
the obtained yellow powder indicates that the residue is Bi O .
2
3
Conclusions
New solid complex of bismuth trichloride and nitrilotriacetic acid can be synthesized
through a solid–solid reaction of the nitrilotriacetic acid and bismuth trichloride at
room temperature. The composition of the sample is BiCl [N(CH COOH) ] . The
3
2
3 2.5
crystal structure of the complex belongs to a triclinic system. The far-infrared spectra
and the thermal analysis indicate a complex formation between the Bi(III) and N
atom of the nitrilotriacetic acid.
*
* *
We thank East China University of Science and Technology and Shanghai Committee of Science
and Technology for their financial support.
References
1
G. Cantos, C. L. Barbieri, M. Iacomini, P. A. J. Gorin and L. R. Travassos, Biochem. J.,
89 (1993) 155.
2
2
3
4
5
6
7
8
9
K. Singh, P. K. Sharma, S. N. Duby and J. P. Tandon, Indian J. Chem., 33(A) (1994) 266.
Z. D. Zhou and F. Mei, Acta Pharm. Sinica, 9 (1962) 1 (Chinese).
J. Kaloustian, A. M. Pauli, G. Pieroni and H. Portugal, J. Therm. Anal. Cal., 70 (2002) 963.
Li Xi, Liu Yi, Wu Jun, Liang Huigang and Qu Songsheng, J. Therm. Anal. Cal., 67 (2002) 589.
T. Kebede, K. V. Ramana and M. S. P. Rao, J. Therm. Anal. Cal., 66 (2001) 439.
S. Z. Hu and W. F. Lin, Chinese J. Struct. Chem., 8 (1989) 249.
P. Kopf-Mair and T. Klapotka, Inorg. Chim. Acta, 49 (1988) 152.
nd
N. N. Greenwood and A. Earnshaw, Chemistry of the Elements, 2 Ed., Reed Educational and
Professional Publ. 1997, p. 553.
1
1
0 Y. C. Guo, S. R. Luan, Y. R. Chen, X. S. Zeng, Y. Q. Jia, G. Q. Zhong and R. K. Ruan,
J. Therm. Anal. Cal., 68 (2002) 1025.
rd
1 K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, 3 Ed.,
Wiley 1978.
J. Therm. Anal. Cal., 76, 2004