Bis-Hydrazine Metal 3, 5-Dinitro Benzoates
and 3, 5-Dinitro Salicylates: Synthesis, Spectral, Thermal and X-ray Powder Diffraction
Studies
D. Santhosh Shanthakumar1 and B.N. Sivasankar2
1Department of Chemistry, Sri Krishna College of Technology,
Kovaipudur, Coimbatore-641 042, Tamilnadu, India.
2Department of Chemistry, Government Arts College, Udhagamandalam, The
Nilgiris-643 002, Tamilnadu, India,
*Corresponding Author E-mail: sivabickol@yahoo.com.
Bis-hydrazine metal
3,5-dinitro benzoates [M(m-C6H3(NO2)2COO)2(N2H4)2]
and bis-hydrazine 3,5-dinitro salicylates [M(m-C6H2(NO2)2(OH)COO)2(N2H4)2],
where M= Mn, Co, Ni, Zn or Cd have been prepared and characterised by chemical
analyses, spectral, thermal and X-ray powder diffraction studies. The infrared
spectra of these complexes suggest the bridging bidentate nature of hydrazine
moieties and monodentate nature of carboxylate ions. The TG-DTA analyses reveal
that both the series of complexes undergo thermal degradations at much lower
temperatures (180-430 oC) to yield respective metal oxides as the
final residue. The X-ray powder data of each set of complexes show isomorphism
within the series.
KEYWORDS: Bis-hydrazine, 3,5-dinitro benzoic acid, 3,5-dinitro salicylic
acid, TG-DTA and X-ray powder diffraction.
INTRODUCTION:
Hydrazine being a versatile ligand forms a variety of complexes
with almost all metals including lanthanides and actinides. Hydrazine can act
as a neutral monodentate, bidentate or bridged bidentate ligand and it
generates hydrazinium cation in acidic medium during complexation in the
presence of carboxylic acids. Besides these, hydrazine complexes are expected
to undergo thermal degradation at lower temperatures due to the presence of
endothermic N-N bond in hydrazine. Hence, metal complexes containing hydrazine
and its derivatives have been utilised and are being exploited as low
temperature precursors to metal oxides with high degree of purity. Aromatic
nitro compounds primarily utilised as explosives. They undergo degradation at
lower temperature when compared to other compounds. The aromatic nitro
compounds such as 3,5-dinitro benzoic acid and 3,5-dinitro salicylic acid are
also used as corrosion inhibitor, photography field and determination of
reducing sugar content respectively.
The coordination complexes containing hydrazine and aromatic
dinitro compounds are expected to perform vigorous thermal decomposition to
yield metal oxides at lower temperatures. A large number of coordination
compounds containing nitro benzoic acid, salicylic acid and their derivatives
have been investigated [1-9]. In spite of a large number of hydrazine complexes
of transition metal carboxylates [10-15] and lanthanide carboxylates [16-18]
have been exhaustively studied. They are mostly limited to aliphatic carboxylic
acids and only few complexes containing aromatic carboxylic acids have been
studied [19-21]. Furthermore, hydrazine metal complexes with nitro benzoates
are scarce in the literature. Hence the present investigation, we wish to
report the preparation, spectral, thermal and X-ray powder diffraction studies
of some bis-hydrazine metal 3,5-dinitro benzoates and 3,5-dinitro salicylates.
EXPERIMENTAL:
Preparation of bis-hydrazine metal 3,5-dinitro benzoates:
Bis-hydrazine metal 3,5-dinitro benzoate complexes were prepared
by adding an aqueous solution containing a mixture of 3,5-dinitro benzoic acid
(12.73 g, 0.06 mol) and hydrazine hydrate (6 mL, 0.12 mol) to an aqueous
solution (50 mL) of respective metal nitrate hydrate (0.03 mol) slowly with
constant stirring. The resultant solution was filtered and allowed to stand at
room temperature. The crystalline complexes settled were collected after six
hours, washed with water and then with alcohol and dried in air.
Preparation of bis-hydrazine metal 3,5-dinitro salicylates:
To an aqueous solution (50 mL) of respective metal nitrate
hydrates (0.03 mol), 3,5-dinitro salicylic acid (13.69 g, 0.06 mol) in 20 mL of
distilled water was added slowly with constant stirring. To this clear solution
an aqueous solution (20 mL) of hydrazine hydrate (6 mL, 0.12 mol) was added
with constant stirring. The clear solution thus obtained was filtered and
allowed for crystallisation. The crystalline precipitates formed after 5-6
hours were filtered, washed with water then with alcohol and dried in air.
Physico-chemical studies:
The compositions of all the complexes were determined by hydrazine
and metal analyses. The hydrazine content in the complexes were determined
volumetrically by titrating against 0.025 mol potassium iodate solution under Andrew’s
condition [22]. The metal content in all the complexes were determined by EDTA
complexometric titrations after decomposing a known amount of the complex with
concentrated nitric acid [22]. Room temperature magnetic measurements were
determined by Gouy’s method using Hg[Co(SCN)4] as a calibrant. The
solid state electronic absorption spectra of the complexes in Nujol mull were
recorded on a Varian Cary 5000 UV-Visible spectrophotometer in the range
200-800 nm. Infrared spectra of the complexes were recorded on a SHIMADZU
spectrophotometer using KBr pellets in the range 4000-400 cm-1. A
Perkin-Elmer CHN analyser (Model 1240) was used for C, H and N analysis. The
simultaneous TG-DTA of the complexes in air was carried out using TG/DTA 6200
Thermal Analyser. The thermal experiments were performed in air with heating
rate of 10 oC min-1 using platinum cups as sample holders.
X-ray powder diffraction pattern of samples were obtained using Bruker D8 Focus
Diffractometer with scan speed 5 seconds per step, using CuKα
radiation (λ= 1.540598 Å) and Scintillation counter as a detector.
RESULTS AND DISCUSSION:
Bis-hydrazine metal 3,5-dinitro benzoates were prepared by the
reaction between respective metal nitrate hydrate and 3,5-dinitro benzoate in
the presence of hydrazine hydrate in aqueous medium. The bis-hydrazine metal
3,5-dinitro salicylate complexes were prepared by adding an aqueous solution of
(20 mL) 3,5-dinitro salicylic acid to metal nitrate hydrate followed by excess
of hydrazine hydrate. The chemical reactions are represented as follows.
3 M(NO3)2.nH2O + 6 C6H3(NO2)2COOH
+ 12 N2H4.H2O
3[M(m-C6H3(NO2)2COO)2(N2H4)2]
+ 6 N2H5NO3+ (3n+12) H2O
Where M = Mn, Co, Ni, Zn or Cd
3 M(NO3)2.nH2O
+ 6 C6H2(OH)(NO2)2COOH + 12 N2H4.H2O
3[M(m-C6H2(OH)(NO2)2COO)2(N2H4)2]
+ 6 N2H5NO3+ (3n+12) H2O
These complexes are stable in air, insoluble in water and organic
solvents such as alcohol and ether. The compositions of the complexes were
assigned on the basis of hydrazine and metal analyses. The analytical data of
these complexes are summarised in Table 1.
Table 1- Analytical data of
metal 3, 5-dinitrobenzoate and 3, 5-dinitrosalicylate complexes.
|
S.No
|
Molecular Formula (Mol. Wt)
|
Hydrazine Calc.(Found)
|
CHN Analysis
|
Yield %
|
|
C % Calc.(Found)
|
H % Calc.(Found)
|
N % Calc. (Found)
|
|
1
|
Mn(m-C6H3(NO2)2COO)2(N2H4)2
(541.25)
|
11.84 (11.50)
|
31.33 (30.12)
|
2.98 (3.01)
|
20.7 (20.35)
|
80
|
|
2
|
Co(m-C6H3(NO2)2COO)2(N2H4)2
(545.24)
|
11.75 (11.15)
|
30.84 (30.48)
|
2.59 (2.4)
|
20.55 (20.24)
|
85
|
|
3
|
Ni(m-C6H3(NO2)2COO)2(N2H4)2
(545)
|
11.76 (12.02)
|
30.85 (30.33)
|
2.59 (2.66)
|
20.55 (20.04)
|
90
|
|
4
|
Zn(m-C6H3(NO2)2COO)2(N2H4)2
(551.7)
|
11.62 (11.62)
|
30.48 (30.18)
|
2.56 (2.42)
|
20.31 (20.13)
|
88
|
|
5
|
Cd(m-C6H3(NO2)2COO)2(N2H4)2
(598.72)
|
10.71 (11.10)
|
28.09 (28.13)
|
2.36 (2.12)
|
18.72 (18.22)
|
87
|
|
6
|
Mn(m-C6H2(NO2)2(OH)COO)2(N2H4)2
(573.25)
|
11.24 (11.62)
|
29.58 (28.93)
|
2.81 (2.91)
|
19.55 (19.1)
|
80
|
|
7
|
Co(m-C6H2(NO2)2(OH)COO)2(N2H4)2
(577.24)
|
11.11 (11.27)
|
29.13 (29.44)
|
2.5 (2.71)
|
19.41 (19.13)
|
86
|
|
8
|
Ni(m-C6H2(NO2)2(OH)COO)2(N2H4)2
(577)
|
11.11 (10.74)
|
29.14 (29.81)
|
2.5 (2.42)
|
19.42 (19.09)
|
88
|
|
9
|
Zn(m-C6H2(NO2)2(OH)COO)2(N2H4)2
(583.7)
|
10.97 (10.41)
|
28.81 (28.17)
|
2.42 (2.68)
|
19.2 (19.31)
|
85
|
|
10
|
Cd(m-C6H2(NO2)2(OH)COO)2(N2H4)2
(630.72)
|
10.16 (10.02)
|
26.66 (26.18)
|
2.24 (2.13)
|
17.77 (17.27)
|
84
|
Magnetic moments and Electronic spectra:
The magnetic moment of the manganese, cobalt and nickel complexes
were found to be 5.8, 5.2 and 3.1 BM indicating their high-spin variety. As
expected zinc and cadmium are diamagnetic. The electronic spectra of manganese
complexes shows sharp and week bands corresponding to spin-forbidden
transitions. The bis-hydrazine cobalt 3,5-dinitro benzoate and 3,5-dinitro
salicylate complexes shows a band at 12,660 cm-1 and 12,500 cm-1
respectively which are assigned to 4T1g(F) 4T1g(P)
transition. The bis-hydrazine nickel 3,5-dinitro benzoate shows two bands at
14,160 cm-1, 19,900 cm-1 and corresponding 3,5-dinitro
salicylate complexes shows bands at 12,850 cm-1, 18,480 cm-1
respectively, which are assigned to 3A2g 3T1g(F)
and 3A2g 3T1g(P)
transitions respectively. These spectral results are characteristics of
octahedral geometry around the metal ions [23].
Infrared spectra:
The infrared spectra of the complexes show three bands in the
region 3100-3300 cm-1 which are ascribable for the N-H stretching
frequencies of hydrazine. The N-N stretching frequencies for these complexes
are observed in the region 970-980 cm-1 which is typical for
bridging bidentate nature of neutral hydrazine molecule [24]. All the
bis-hydrazine complexes show two bands in the region 1600-1630 cm-1
and 1380-1390 cm-1 for νasy and νsym
stretching respectively of carboxylate ions with ∆ν separation of
220-240 cm-1 indicating the monodentate coordination of
carboxylate groups [25]. The bands at 1520-1540 cm-1 and 1340-1350
cm-1 were assigned to asymmetric and symmetric vibrations
respectively of the nitro groups. In the case of bis-hydrazine metal
3,5-dinitro salicylate complexes an additional broad band is observed at 3440
cm-1 for O-H stretching of hydroxyl group. The infrared spectra of
bis-hydrazine cadmium 3,5-dinitro benzoate and bis-hydrazine zinc 3,5-dinitro
salicylate complexes are given in Fig.1 and 2 as representative examples.
Fig. 1-Infrared spectrum of bis-hydrazine cadmium 3,5-dinitro
benzoate
Fig. 2- Infrared spectrum of bis-hydrazine zinc 3,5-dinitro
salicylate
Thermal degradation:
The hydrazine complexes are sensitive to heat and known for their
low temperature decomposition due to the endothermic nature of N-N bond in
hydrazine. In the present series of complexes is expected to decompose even at
very low temperature due to the presence of hydrazine molecule as well as the
presence of nitro group. The thermal profile of these complexes also reflects
the same.
Thermal degradation of bis-hydrazine metal 3, 5-dinitro benzoates:
The Manganese complex undergoes decomposition in two stages in the
temperature range 130-180 oC and 390-420 oC. The first
stage corresponds to the loss of one hydrazine molecule to give mono hydrazine
complex which further undergo decomposition to yield Mn2O3
as the final residue. The weight loss obtained is 6 % which is good agreement
with the calculated weight loss 5.9 %. The DTA shows an endotherm at 160oC
corresponding to the elimination of one hydrazine molecule and another exotherm
at 413 oC corresponding to the decomposition of mono hydrazine
complexes. The cobalt complex decomposes in a single step in the temperature
range 200-250 oC results in the formation of Co2O3
as the final residue. DTA shows an exotherm at 220 oC corresponding
to this stage. Similarly the nickel complex shows single step degradation
between 280-320 oC to give NiO. DTA shows an exotherm at 298 oC
corresponding to the above stage. Unlike cobalt and nickel complexes, the zinc
complex shows two stage decomposition in the temperature range 180-250 oC
and 390-430 oC. The DTA shows an exotherm at 238 oC
corresponding to elimination of two hydrazine molecules and another exotherm
observed with peak temperature 410 oC corresponding to ligand
pyrolysis to yield ZnO as the final residue. The cadmium complex exhibit single
step decomposition in the temperature range 280-340 oC and the DTA
shows an exotherm at 310 oC. The final product obtained in this
decomposition is CdO.
Thermal degradation of bis-hydrazine metal 3, 5-dinitro
salicylates:
The manganese complex also shows two stage decomposition in the
temperature range 90-120 oC and 200-230 oC. The DTA shows
an endotherm at 105 oC corresponding to the elimination of one
hydrazine molecule. The weight loss obtained is 6 % which is good agreement
with the calculated weight loss. Another exotherm is observed at 220 oC
corresponding to the decomposition of mono hydrazine compound to yield Mn2O3
as the final residue. The cobalt complex decomposes in single stage in
the temperature range 200-220 oC to yield cobaltic oxide as end
product. This step is exothermic with the peak temperature at 218 oC.
The nickel complex also decomposes in single stage between the temperature
ranges 240-260 oC. DTA shows an exotherm at 256 oC
corresponding to the above step. Unlike manganese, cobalt and nickel complexes,
the zinc complex shows two distinct exotherm at 234 and 345 oC. In
the first stage two hydrazine molecules are lost to give zinc 3,5-dinitro
salicylate as intermediate. This intermediate further undergoes ligand
pyrolysis in the temperature range 330-360 oC to yield ZnO as final
residue. The single step decomposition of cadmium complex resulted in the
formation of CdO. DTA shows an exotherm at 236 oC. The TG mass loss
is observed in the temperature range 220-240 oC. The simultaneous
TG-DTA of bis-hydrazine zinc 3,5-dinitro benzoate and bis-hydrazine cobalt
3,5-dinitro salicylate complexes are given in Fig. 3 and 4 respectively. The
thermal degradation data of the complexes are given in Table 2.
Table 2-Simultaneous TG-DTA
analysis data of metal 3, 5-dinitrobenzoate and 3, 5-dinitrosalicylate
complexes.
|
S.No
|
Compound
|
DTA Peak
Temp(oC)
|
TG-Temp. range (oC)
|
weight loss
Found (Calc.)
|
Residue
|
|
1
|
Mn(m-C6H3(NO2)2COO)2(N2H4)2
|
160 (endo)
|
130-180
|
6 (5.9)
|
Mn(m-C6H3(NO2)2COO)2(N2H4)
|
|
413 (exo)
|
390-420
|
85 (85.42)
|
Mn2O3
|
|
2
|
Co(m-C6H3(NO2)2COO)2(N2H4)2
|
238 (exo)
|
200-250
|
84 (84.8)
|
Co2O3
|
|
3
|
Ni(m-C6H3(NO2)2COO)2(N2H4)2
|
298 (exo)
|
280-320
|
85 (86.3)
|
NiO
|
|
4
|
Zn(m-C6H3(NO2)2COO)2(N2H4)2
|
238 (exo)
|
180-250
|
11 (11.6)
|
Zn(m-C6H3 (NO2)2COO)2
|
|
410 (exo)
|
390-430
|
84 (85.2)
|
ZnO
|
|
5
|
Cd(m-C6H3(NO2)2COO)2(N2H4)2
|
310 (exo)
|
280-340
|
77 (78.6)
|
CdO
|
|
6
|
Mn(m C6H2(NO2)2(OH)COO)2(N2H4)2
|
105 (endo)
|
90-120
|
6 (5.58)
|
Mn(mC6H2(NO2)2(OH)COO)2(N2H4)
|
|
220 (exo)
|
200-230
|
86 (86.23)
|
Mn2O3
|
|
7
|
Co(m-C6H2(NO2)2(OH)COO)2(N2H4)2
|
218 (exo)
|
200-220
|
86 (85.6)
|
Co2O3
|
|
8
|
Ni(m-C6H2(NO2)2(OH)COO)2(N2H4)2
|
256 (exo)
|
240-260
|
85 (87)
|
NiO
|
|
9
|
Zn(m-C6H2(NO2)2(OH)COO)2(N2H4)2
|
234 (exo)
|
200-240
|
11 (10.9)
|
Zn(m-C6H2(NO2)2(OH)COO)2
|
|
345 (exo)
|
330-360
|
85 (86.1)
|
ZnO
|
|
10
|
Cd(m-C6H2(NO2)2(OH)COO)2(N2H4)2
|
236 (exo)
|
220-240
|
80 (79.6)
|
CdO
|
Fig. 3-Simultaneous TG-DTA
of bis-hydrazine zinc 3,5-dinitro benzoate
Fig. 4-Simultaneous TG-DTA
of bis-hydrazine cobalt 3,5-dinitro salicylate
X-ray powder diffraction:
The X-ray powder diffraction patterns of each series of complexes
are super imposable among themselves indicating their structural similarity.
The 'd' values for cadmium and zinc 3,5-dinitro benzoate and bis-hydrazine
3,5-dinitro salicylate complexes are given in Table 3 and 4 respectively. The
X-ray powder diffraction patterns of bis-hydrazine zinc 3,5-dinitro benzoate
and bis-hydrazine zinc 3,5-dinitro salicylate complexes are shown in Fig. 5 and
6 respectively.
Table 3-X-ray powder diffraction data of
M(m-C6H3(NO2)2COO)2(N2H4)2
|
Cd
|
Zn
|
|
2θ
|
INTENSITY
|
d VALUE
|
2θ
|
INTENSITY
|
d VALUE
|
|
13.10
|
81.10
|
6.7529
|
10.30
|
50.30
|
8.5814
|
|
13.60
|
79.50
|
6.5057
|
10.95
|
47.90
|
8.0771
|
|
14.05
|
75.80
|
6.2988
|
11.54
|
49.10
|
7.6640
|
|
15.07
|
100.00
|
5.8739
|
12.12
|
45.40
|
7.2990
|
|
15.60
|
87.90
|
5.6758
|
13.60
|
41.70
|
6.5057
|
|
17.19
|
65.90
|
5.1555
|
14.39
|
85.90
|
6.1524
|
|
17.80
|
72.70
|
4.9779
|
15.00
|
100.00
|
5.9023
|
|
21.30
|
60.60
|
4.1681
|
15.50
|
58.90
|
5.7122
|
|
21.77
|
62.90
|
4.0795
|
17.67
|
58.90
|
5.0159
|
|
22.27
|
62.90
|
3.9883
|
18.90
|
60.70
|
4.6909
|
|
23.00
|
69.70
|
3.8637
|
20.76
|
49.10
|
4.2759
|
|
23.80
|
53.80
|
3.7356
|
21.30
|
34.40
|
4.1681
|
|
25.76
|
41.70
|
3.4563
|
21.96
|
36.80
|
4.0441
|
|
27.57
|
53.00
|
3.2332
|
22.40
|
42.30
|
3.9658
|
|
28.44
|
44.70
|
3.1357
|
23.54
|
45.40
|
3.7758
|
|
28.69
|
49.20
|
3.1093
|
24.54
|
52.10
|
3.6245
|
|
34.04
|
47.70
|
2.6314
|
25.10
|
35.00
|
3.5450
|
|
34.53
|
40.20
|
2.5956
|
26.10
|
41.10
|
3.4114
|
|
36.56
|
34.80
|
2.4561
|
26.36
|
42.90
|
3.3783
|
|
39.32
|
34.80
|
2.2897
|
27.12
|
33.70
|
3.2849
|
|
39.82
|
40.90
|
2.2618
|
27.88
|
40.50
|
3.1971
|
|
41.36
|
40.20
|
2.1812
|
28.45
|
30.10
|
3.1346
|
|
41.81
|
34.10
|
2.1590
|
28.80
|
42.30
|
3.0970
|
|
42.19
|
31.10
|
2.1401
|
34.11
|
31.30
|
2.6268
|
|
44.70
|
30.30
|
2.0257
|
34.90
|
31.90
|
2.5685
|
Fig. 5- X-ray powder diffraction pattern of bis-hydrazine zinc
3,5-dinitro benzoate
Fig. 6- X-ray powder diffraction pattern of bis-hydrazine zinc
3,5-dinitro salicylate
REFERENCE:
1.
F. Hu, X. Yin, Y. Feng.
Y. Mi and S. Zhang. Acta Cryst., 65,210 (2009)
2.
H. Nacefoglu, W. Clegg
and A.J. Scott, Acta Crys., 57, 472 (2001)
3.
B.R. Srinivasan and
G.K. Rane, J. Chem. Sci., 121, 145 (2009)
4.
A. Arslants, A.K.
Devrim and H.Necefoglue, Int.J.Mol.Sci., 8. 564 (2007)
5.
Ye-Dan Shen and
Jain-Linin, Z.Kristallogr., NCS, 228, 25 (2013)
6.
J. Medvecka, J. Moncol,
V. Jorik and D.Valigura, Acta Chimica Slovaca, 3, 83 (2010)
7.
W. Ferenc, A.W
Dzlewulska, B. Cristovo and J. Sarzyanski, J. Serb. Chem. Soc., 71, 929 (2006)
8.
M. Gembicky, J.Moncol,
K. Lebruskova, L. Martiska and D. Valigura, Acta Chimica Slovaca, 1, 290 (2008)
9.
S.K.Gupta, R.C. Sharma
and A.K. Gupta, Asian Journal of Chem., 4, 234 (1992)
10. B.N. Sivasankar and S.Govindarajan, Synth.
React. Inorg. Met-org. Chem., 25 (1), 31 (1995)
11. B.N. Sivasankar, J. Therm. Anal. and Cal.,
86, 385 (2006)
12. B.N. Sivasankar, J.R. Sharmila and L.
Ragunath, Synth. React. Inorg. Met-org. Chem., 34, 1787 (2004)
13. B.N. Sivasankar, S. Govindarajan, N. Saravanan
and K.K. Mohamed Yusuff, Synth. React. Inorg. Met-org. Chem., 24, 703 (1994)
14. S. Yasodhai and S.Govindarajan, J.Therm.
Anal. and Cal., 62, 737 (2000)
15. B.N. Sivasankar, J.Therm. Anal. and Cal.,
86, 385 (2006)
16. L. Vikram and B.N. Sivasankar, Indian J.
Chem., 47A, 25 (2008)
17. R. Raju and B.N. Sivasankar, J.Therm. Anal.
and Cal., 94(1), 289 (2008)
18. K. Karuppusamy and S.Govindarajan,
Thermochimica Acta, 279, 143 (1996)
19. K. Karuppusamy and S.Govindarajan, Synth.
React. Inorg. Met-org. Chem., 26, 225 (1996)
20. K. Karuppusamy and S. Govindarajan, Eur.
J.Solid State Inorg. Chem., 32, 997 (1995)
21. K. Karuppusamy and S. Govindarajan,
Thermochimica Acta, 274, 125 (1996)
22. I. A. Vogal, A Text Book of Quantitative
Inorganic Analysis, Longmans, London, 2nd Edition, 1951
23. A. B. P. Lever, Inorganic Electronic
Spectroscopy, 2nd Edition, Elsevier, Amsterdam 1984
24. A. Braibanti, F. Dallevalle, M. A.
Pellinghelli and E. Leporati, Inorg. Chem., 7, 1430 (1968)
25. K. Nakamoto, Infrared and Raman spectra of
Inorganic and Coordination Compounds, 3rd Edition,
Wiley/Interscience, New York 1978.