Spectral and thermal studies of transition metal complexes of acetamido benzoic acids with hydrazine

Article abstract of DOI:10.14233/ajchem.2013.12895

The metal complexes of isomeric acetamido benzoic acids with Co, Ni, Zn and Cd metals have been prepared and characterized by analytical, spectroscopic (IR, UV reflectance), micro elemental analysis, simultaneous TG-DTA, powder XRD, magnetic susceptibilit

Full text of DOI:10.14233/ajchem.2013.12895

Asian Journal of Chemistry; Vol. 25, No. 1 (2013), 209-216
http://dx.doi.org/10.14233/ajchem.2013.12895
Spectral and Thermal Studies of Transition Metal Complexes of
Acetamido Benzoic Acids with Hydrazine
1
2,*
E. HELEN PRICILLA BAI and S. VAIRAM
1Department of Chemistry, Park College of Engineering and Technology, Coimbatore-641 659, India
2Department of Chemistry, Government College of Technology, Coimbatore-641 013, India
*Corresponding author: E-mail: vamshen@yahoo.com
(Received: 20 October 2011;
Accepted: 16 July 2012)
AJC-11849
The metal complexes of isomeric acetamido benzoic acids with Co, Ni, Zn and Cd metals have been prepared and characterized by
analytical, spectroscopic (IR, UV reflectance), micro elemental analysis, simultaneous TG-DTA, powder XRD, magnetic susceptibility
measurements and SEM-EDS studies: [Ni(2-acamb)2(N2H4)].2H2O; [M(2-acamb)2(N2H4)].H2O, where M = Co, Cd and Zn; [M(3-
acamb)2(N2H4)].H2O, where M = Ni and Co and [M(3-acamb)2(N2H4)].2H2O where M = Cd and Zn; [Co(4-acamb)2(N2H4)].H2O and
[M(4-acamb)2(N2H4)].2H2O where M = Ni, Cd and Zn, 2-acambH = 2-acetamido benzoic acid, 3-acambH = 3-acetamido benzoic acid
and 4-acambH = 4-acetamido benzoic acid. Among them Ni, Co and Cd complexes of 2-acambH and 4-acambH were obtained at pH 5
and 6 respectively, whereas Zn complexes of both acids were formed at pH 3. 3-acambH complexes were prepared at pH 5. The IR spectra
of the compounds display the N-N stretching frequency absorptions in the range of 984-926 cm-1, which reveals the bridging bidentate
coordination of hydrazine. The compounds show ν(C=O) (asym) values in the range 1611-1582 cm-1 and the ν(C=O) (sym) values at
1555-1422 cm-1. The difference of ν(C=O) (asym) and ν(C=O) (sym), which is found to be 48-162 cm-1, indicates that the carboxylate
anion is coordinated to the metal ion in the bidendate fashion. These complexes undergo dehydration in the range of 140-177 ºC first and
then oxidative decomposition showing exotherms in the range of 200-278 ºC and in the range of 400-682 ºC to their respective metal
oxides. Cadmium and zinc complexes show their intermediates as carbonates. The electronic spectra and the magnetic susceptibility
values suggest that the coordination number of the complexes is 6 with distorted octahedral geometry. XRD patterns show isomorphism
among the complexes with similar molecular formulae. The SEM-EDS studies reveal the presence of respective metal oxides.
Key Words: IR, Simultaneous TG-DTA, Acetamido benzoate, Electronic spectra.
INTRODUCTION
structures of the isomeric forms acetamido benzoic acids are
given in the Figs. 1-3.
Hydrazine is the simplest diamine containing two lone
pair of electrons. It forms variety of compounds with more
COOH
COOH
O
C
COOH
number of carboxylic acids, such as simple aliphatic mono
and di carboxylic acids1,2 aromatic mono and di carboxylic
acids3,4 tri and tetra carboxylic acids5,6, which have been
reported in the literature. Many bis-hydrazine and hydrazinium
metal carboxylates are used as precursors for metal oxides
and mixed metal oxides7-15. Though studies have been done
on 4-acetamido benzoate synthesis of lanthanide coordination
polymers using 4-acetamido benzoic acid and various modes
of coordination of 4-acetamido benzoate (monodentate, chela-
ting and multidentate bridging nature)16-20, a detailed study of
transition metal complexes of isomeric acetamido benzoic
acids in the presence of hydrazine has not been attempted so
far. In this paper, we report the synthesis, spectral and thermal
studies of some transition metal complexes of 2-acetamido,
3-acetamido and 4-acetamido benzoates with hydrazine. The
NH
CH
3
O
C
NH
CH
3
O
NH
C
CH
3
Fig. 1. 2-Acetamido benzoic
acid (2-acambH)
Fig. 2. 3-Acetamido benzoic
acid (3-acambH)
Fig. 3. 4-Acetamido benzoic
acid (4-acambH)
EXPERIMENTAL
The chemicals and solvents used were of AR grade
received from Fluka chemicals. The double distilled water was
used for the preparation and chemical analyses. Hydrazine
hydrate 99.99 % pure was used as such.
Preparation of [M{(2-),(3-) and (4-) acamb)}2(N2H4)].
xH2O, where 2-acambH =2-acetamido benzoic acid, M =

210 Bai et al.
Asian J. Chem.
Ni and x = 2 and M = Co, Cd and x = 1; where 3-acambH
= 3-acetamido benzoic acid, M = Ni, Co and x = 1 and M =
Cd and x = 2; where 4-acambH = 4-acetamido benzoic acid
M = Ni, Cd and x = 2 and M = Co and x = 1.
organic solvents, the electronic reflectance spectra were
recorded in solid-state. Based on the absorptions term states
4
4
4
3
assigned are T1g (P) → T2g and A2g for cobalt and T2g
→
3T1g and 1Eg for nickel complexes. These assignments evidence
the distorted octahedral geometry of the complexes21. The
magnetic moment values obtained for the cobalt and nickel
complexes were 5.20 and 3.31 BM respectively, which supports
the geometry of cobalt and nickel compounds.
The complexes were prepared by adding an aqueous solu-
tion of metal nitrate [e.g., Ni(NO3)2.6H2O, 0.291 g, 1 mmol in
20 mL of H2O] to a clear solution obtained by mixing hydrazine
hydrate (99.99 % pure, 0.1 g, 2 mmol) with a slurry of acetamido
benzoic acid (0.1792 g, 1 mmol in 60 mL of hot water). Crysta-
lline products of complexes were formed when the solution
mixture was heated over a hot water bath at 80 ºC.
2-Acetamido benzoic acid complexes were formed at pH
5 immediately whereas 3-acetamido and 4-acetamido benzoic
acid complexes formed at pH 5 when the reaction mixture is
heated for 90 min and at pH 6 when heated for 2h 30 min
respectively.
The complexes formed were filtered through filter paper,
washed with distilled water, ethanol then with ether and dried
in a desiccator.
Preparation of [Zn(acamb)2(N2H4)].xH2O, where 2-
acambH = 2-acetamidobenzoic acid and x = 1 and 3-
acambH = 3-acetamido benzoic acid, 4-acambH = 4-
acetamidobenzoic acid and x = 2.
TABLE-1
ELECTRONIC SPECTRA VALUES OF THE COMPLEXES
Complex
[Ni(2-acamb)2N2H4].
2H2O
Absorption maximum (cm-1) Assignment
20534, 16807 and 15408
8313, 7257 and 6725
20000, 16447, 13459 and
12136
8224 and 7257
20000 and 13459
11933
7955 and 6064
21186
11806
8467, 7348 and 6667
23148
11561
8313, 7117, 6489 and 5780
12755
3T1g
3T2g
3T1g
[Ni(3-acamb)2(N2H4)].
H2O
3T2g
3T1g
[Ni(4-acamb)2(N2H4)].
2H2O
1Eg
3T2g
4T1g(P)
4A2g
4T2g
[Co(2-acamb)2(N2H4)].
H2O
4T1g(P)
4A2g
4T2g
[Co(3-acamb)2(N2H4)].
H2O
These complexes were also prepared by the same
procedure in absolute alcohol medium. As mentioned above,
complexes of 2 isomer were formed immediately at pH 3 and
those of 3 and 4 isomers were formed at pH 5 and 3 in 90 min
and 2 h 30 min respectively.
4A2g
4T2g
[Co(4-acamb)2(N2H4)].
H2O
8224, 7184, 6667 and 6017
IR spectra of complexes: The IR spectral data of the
complexes are summarized in Table-2. The pka values of
2-acambH, 3-acambH and 4-acambH were found to be 3.63,
4.07 and 4.28 respectively. These indicate that 4-isomer is least
acidic and the lowest value of ν(C=O) 1672 cm-1 of the same
may be due to its highest pka value.
The complexes were filtered, washed and dried as
mentioned above.
Physico-chemical techniques: The composition was
established by chemical analysis. Hydrazine content was
determined by titrating against standard KIO3 solution (0.025
mol L-1) under Andrew's conditions20. The metal content was
determined by EDTA (0.01 mol L-1) complexometric titration20
after decomposing a known weight of the sample with 1:1 HNO3.
Magnetic measurements were carried out by using Guoy balance
and Gauss meter DGM102 (Besto) keeping Hg[Co(NCS)4] as
calibrant. The electronic spectra for solid state complexes were
obtained using aVarian, Cary 5000 recording spectrophotometer.
Infrared spectra were recorded using KBR disc (4000-400 cm-1)
on a Shimadzu FTIR-8201 (PC)S spectrophotometer. The
simultaneous TG-DTA studies were done on a Perkin Elmer,
Diamond TG/DTA analyzer and the curves were obtained using
5-10 mg of the samples at the heating rate of 10 ºC per min in
air atmosphere. Platinum cups were employed as sample holders
and alumina as reference and the temperature range was ambient
to 700 ºC. The XRD patterns were recorded on a Bruker AXS
D8 advance diffractometer with an X-ray source Cu, wave-
length 1.5406 Å using a Si (Li) PSD detector. The elemental
analysis was carried out using an ElementarVario ELIII CHNS
elemental analyzer. The SEM with EDS analysis was obtained
using JEOL model JSM-6390 LV and JEOL model JED-2300
instrument.
The IR spectra of pure acids show absorption at 1707,
1694 and 1672 cm-1 corresponding to ν(C=O) (acid). But the
spectra of complexes show ν(C=O) asym (acid) at 1582-1611
cm-1 and ν(C=O) sym (acid) in the range 1555-1422 cm-1 with
the difference of 48-162 cm-1 between ν(C=O) (asym) and
ν(C=O) (sym), which supports the bidental coordination of
carboxylate ions to metal. The absorption at 984-926 cm-1
observed in IR spectra of complexes is assigned to ν(N-N)
stretching of hydrazine present in the complexes, which
reveals that N2H4 is coordinated to metal ion in bridged
bidentate fashion. The O-H stretch of water molecules are
noticed at 3543-3304 cm-1 in all complexes.An additional band
observed at 594-518 cm-1 also supports the presence of lattice
water molecules22. The C=O frequency of amide group of the
compounds is observed at 1709-1635 cm-1. The N-H stretching
frequencies of amide and that of hydrazine are found to be a
merged broad band at 3281-3173 cm-1.
Thermal data of all the complexes are given in Table-3.
Thermal data of [M(2-acamb)2(N2H4)2].xH2O complexes,
where M = Ni and x = 2, where M = Co, Cd and Zn and x = 1
The 2-acambH complexes show endothermic dehydration
in the range 140-177 ºC. The high temperature dehydration
reveals that these lattice water molecules are held up strongly22.
Co and Cd complexes show exothermic dehydrazi-nation at
214-275 ºC, whereas the dehydrazination was not clearly visible
in Ni and Zn compounds.
RESULTS AND DISCUSSION
Electronic spectra and magnetic susceptibility: The
absorption maximum and assignments are summarized in
Table-1. Since the complexes were insoluble in water and

Vol. 25, No. 1 (2013)
Studies of Transition Metal Complexes of Acetamido Benzoic Acids with Hydrazine 211
TABLE-2
ANALYTICAL AND IR DATA OF COMPLEXES
Analytical data
IR data (cm-1) b = broad; s = sharp; m = medium
C
Found
(calc.)
H
Found
(calc.)
N
Found
(calc.)
N2H4
Found
(calc.)
M
Found
(calc.)
ν
ν
ν (C=O)
(amido
gp)
ν
ν
(OH)
ν
ρr
ν
m.f.
(C=O) (C=O)
asym sym
(N-N)
(N-H)
H2O (M-O)
2-acambH complexes
[Ni(2-acamb)2 45.6(44.7) 4.4(5.0) 12.0(11.6) 6.4(6.6) 12.9 (12.2) 1595 b 1433 b 964 s 3464 b
N2H4]·2H2O
3233 b 1684 m 527 s 422 m
[Co(2-acamb2
(N2H4)]·H2O
46.0(46.4) 4.3(4.8) 12.1(12.0) 6.4(6.9)
12.4(12.7) 1589 s 1439 s 966 s 3304 m 3175 m
1661 s 594 s 438 s
[Cd(2-acamb)2 41.8(41.6) 4.3(4.3) 10.7(10.8) 6.3(6.2)
(N2H4)]·H2O
[Zn(2-acamb)2 45.3(45.8) 4.5(4.7) 11.8(11.9) 6.8(6.8)
(N2H4)]·H2O
21.3(21.7) 1584 b 1422 b 959 s 3543 s
13.7(13.9) 1599 s 1447 s 970 s 3320 s
3235 b 1676 m 594 s 509 s
3219 b
1661 s 567 s 463 s
3-acambH complexes
[Ni(3-acamb)2 46.5(46.4) 4.5(4.8) 12.0(12.0) 6.7(6.9)
(N2H4)]·H2O
[Co(3-acamb)2 46.4(46.4) 4.7(4.8) 12.1(12.0) 6.9(6.9) (12.6(12.7) 1611 m 1487 s 980 s 3339 s
(N2H4)]·H2O
[Cd(3-acamb)2 41.3(40.2) 4.2(4.5) 10.9(10.4) 6.5(6.0)
(N2H4)]·2H2O
12.4(12.6) 1582 s 1460 s 984 s 3392 b
3227 b
3271 b
3281 s
3215 b
1709 b 525 s 476 m
1635 b 552 s 459 s
1659 s 559 s 459 s
1607 b 559 s 430 s
20.1(20.9) 1611 s 1462 s 926 m 3376 b
14.3(13.4) 1607 s 1487 s 974 s 3305 s
4-acambH complexes
[Zn(3-acamb)2 43.9(44.1) 4.7(4.9) 11.6(11.4) 7.0(6.5)
(N2H4)]·2H2O
[Ni(4-acamb)2 44.4(44.7) 4.5(5.0) 11.8(11.6) 7.4(6.6)
13.2(13.1) 1609 b 1530 b 964 s 3360 m 3183 b 1672 m 544 s 500 s
(N2H4)]·2H2O
[Co(4-acamb)2 46.2(46.4) 4.7(4.8) 12.0(12.0) 6.7(6.9)
(N2H4)]·H2O
[Cd(4-acamb)2 41.2(40.2) 3.8(4.5) 11.3(10.4) 6.2(6.0)
(N2H4)]·2H2O
[Zn(4-acamb)2 44.7(44.1) 4.1(4.9) 12.4(11.4) 7.0(6.5)
(N2H4)·2H2O]
12.8(12.7) 1601 b 1528 b 968 s 3335 b
21.3(20.9) 1603 b 1555 b 964 s 3377 b
14.4(13.4) 1597 s 1521 s 972 s 3315 s
3173 b
3260 b
1680 b 546 s 500 s
1668 b 581 s 500 s
3270 b 1672 m 518 s 503 s
The cadmium complex shows a broad exotherm at 400 ºC
indicating the formation of metal carbonate intermediate23,24
and the corresponding weight loss is observed between 300-
470 ºC in its thermogravimetric curve. It is also inferred that
the complex undergoes oxidative decomposition to form the
metal oxide residue, which is accompanied by an exothermic
doublet at 490 and 556 ºC indicating the weight loss temperature
of 470-700 ºC.
The TG-DTA curves of Ni, Co and Zn complexes show
that the dehydrazinated metal carboxylates decompose to give
the metal oxide as their final residue. As the intermediates are
highly unstable and they could not be isolated. They show
exotherms in the range 420-500 ºC attributing the formation
of metal oxide residue with the mass loss temperature in the
range of 200-700 ºC is observed in their TG.
Thermal data of [M(3-acamb)2(N2H4)2].xH2O; where M =
Ni, Co and x = 1; M = Cd, Zn and x = 2
Similar to 2-acambH complexes, 3-acambH complexes
show an endothermic dehydration at 122-160 ºC. Ni and Co
complexes show exothermic dehydrazination in the range of
230-260 ºC, while Cd and Zn complexes do not. The inter-
mediates of Ni, Co and Zn compounds were unstable and could
not be identified. They further decompose to their respective
metal oxides at 500-600 ºC. In case of cadmium oxidative
decomposition occurs via its carbonate intermediate. Its
decomposition temperature, 494 ºC was comparable to that of
the reported6, with the corresponding weight loss between 400-
700 ºC.
Reaction Scheme-II
The reaction scheme of 3-acetamidobenzoate complexes
is given as follows:
122-160 ºC
Reaction Scheme-I
The reaction scheme of the 2-acambH complexes is given
below:
140-177 ºC
[M{C6H4(CH3CONH)COO}2(N2H4)]·xH2O
-H2O
[M{C6H4(CH3CONH)COO}2(N2H4)]
where, M = Ni, Co, Cd and Zn
[M{C6H4(CH3CONH)COO}2(N2H4)]·xH2O
-H2O
230-260 ºC
[M{C6H4(CH3CONH)COO}2(N2H4)]
where, M = Ni, Co, Cd and Zn
[M{C6H4(CH3CONH)COO}2(N2H4)]
-N2H4
[M{C6H4(CH3CONH)COO}2]
214-275 ºC
[M{C6H4(CH3CONH)COO}2(N2H4)]
where, M = Ni and Co
-N2H4
446-600 ºC
[M{C6H4(CH3CONH)COO}2)]
where, M = Ni, Co, and Zn and CoO = Co3O4
[MO]
M{C6H4(CH3CONH)COO}2
where, M = Co and Cd
210-317 ºC
420-500 ºC
[Cd{C6H4(CH3CONH)COO}2)]
CdCO3
CdO
M{C6H4(CH3CONH)COO}2
MO
494-700 ºC
where, M = Ni, Co and Zn and CoO = Co3O4)
400 ºC
[Cd{C6H4(CH3CONH)COO}2]
CdCO3
CdO
Thermal data of [M(4-acamb)2(N2H4)2].xH2O; where M =
Ni, Cd, Zn and x = 2; M = Co and x = 1
490-556 ºC

212 Bai et al.
Asian J. Chem.
TABLE-3
THERMAL DATA OF COMPLEXES
Thermogravimetry
Complex
DTA Temp. (ºC)
Nature of the reaction
Weight Loss (%)
Temp. Range
60-200
Obsd.
7.1
Calcd.
7.2
150(+)
278(-)
420(-)
177(+)
214(-)
400(-)
160(+)
275(-)
400(-)
490(-)
556(-)
140(+)
274(-)
500(-)
140(+)
260(-)
500(-)
590(-)
160(+)
230(-)
446(-)
540(-)
600(-)
122(+)
210(-)
317(-)
494(-)
620(-)
145(+)
240(-)
468(-)
553(-)
175(+)
251(-)
401(-)
486(-)
120(+)
239(-)
324(-)
390(-)
450(-)
150(+)
240(-)
401(-)
625(-)
682(-)
145(+)
236(-)
350(-)
533(+)
Dehydration
[Ni(2-acamb)2N2H4]·2H2O
[Co(2-acamb2(N2H4)]·H2O
200-700
60-190
190-300
300-700
40-180
180-300
300-480
480-700
84.3
4.0
10.5
82.6
3.6
9.8
57.1
75.0
84.5
3.9
10.7
82.8
3.5
9.6
57.1
75.2
Formation of nickel oxide
Dehydration
Dehydrazination
Formation of cobalt oxide (Co3O4)
Dehydration
Dehydrazination
[Cd(2-acamb)2(N2H4)]·H2O
Formation of cadmium carbonate
Formation of cadmium oxide
100-180
180-700
3.9
83.0
3.8
82.7
Dehydration
Formation of zinc oxide
[Zn(2-acamb)2(N2H4)]·H2O
[Ni(3-acamb)2(N2H4)]·H2O
100-200
200-400
3.6
10.7
3.9
10.8
Dehydration
Dehydrazination
4000-700
120-200
200-340
84.7
3.8
10.5
84.9
3.9
10.7
Formation of nickel oxide
Dehydration
Dehydrazination
[Co(3-acamb)2(N2H4)]·H2O
[Cd(3-acamb)2(N2H4)]·2H2O
340-700
83.8
83.9
Formation of cobalt oxide
80-200
200-400
6.6
55.2
6.7
55.0
Dehydration
Formation of cadmium carbonate
400-700
100-200
200-700
76.1
7.2
76.0
7.5
Formation of cadmium oxide
Dehydration
[Zn(3-acamb)2(N2H4)]·2H2O
[Ni(4-acamb)2(N2H4)]·2H2O
83.4
83.3
Formation of zinc oxide
50-190
190-390
390-700
7.4
14.0
85.3
7.5
14.1
85.5
Dehydration
Dehydrazination
Formation of nickel oxide
60-180
180-280
4.0
10.6
3.9
10.7
Dehydration
Dehydrazination
[Co(4-acamb)2(N2H4)]·H2O
280-700
50-180
180-320
320-460
460-800
82.6
6.8
12.9
55.0
75.8
82.8
6.7
12.7
55.2
76.0
Formation of cobalt oxide (Co3O4)
Dehydration
Dehydrazination
Formation of cadmium carbonate
Formation of cadmium oxide
[Cd(4-acamb)2(N2H4)]·2H2O
[Zn(4-acamb)2(N2H4)]·2H2O
75-160
7.2
7.4
Dehydration
160-400
400-600
63.8
83.9
64.0
84.0
Formation of zinc carbonate
Formation of zinc oxide
4-acambH complexes show endothermic dehydration at
120-175 ºC. Exothermic dehydrazination is observed between
239-251ºC for Ni, Co and Cd complexes and no distinct step
was observed in case of Zn complex.
diate5,6, which decompose further to their metal oxides showing
broad exotherms in the range of 533-682 ºC showing the mass
loss between 400-800 ºC, to 75.8 % for cadmium and 83.9 %
for zinc.
Ni and Co complexes undergo oxidative decomposition
to their metal oxide as final residue accompanied by the
exotherms in the range 324-486 ºC with a corresponding
weight loss between 230-700 ºC.
The TG-DTA of [Ni(2-acamb)2(N2H4)].2H2O, [Cd(3-
acamb)2(N2H4)].2H2O and [Zn(4-acamb)2(N2H4)]. 2H2O
complexes are shown as representative examples in Figs. 4-6.
Reaction Scheme-III
In the final step, cadmium and zinc show exothermic
decomposition at 350 and 401 ºC via the carbonate interme-
The reaction scheme of 4-acetamidobenzoate complexes
are given as follows:

Vol. 25, No. 1 (2013)
Studies of Transition Metal Complexes of Acetamido Benzoic Acids with Hydrazine 213
122-175 ºC
All the complexes were found to be crystalline even
though compounds of 2-acambH show more crystallinity.
[M{C6H4(CH3CONH)COO}2(N2H4)]·xH2O
-H2O
[M{C6H4(CH3CONH)COO}2(N2H4)]
SEM-EDX studies: The SEM-EDX images of metal
oxides of the complexes [Co(2-acamb)2(N2H4)]·H2O, [Cd(3-
acamb)2(N2H4)]·2H2O and [Zn(4-acamb)2(N2H4)]·2H2O are
given as representative examples in Figs. 7-12. These metal
oxides are obtained by incinerating the corresponding
complexes at their decomposition temperature followed by
sintering them for 0.5 h. They have yielded probably nanosized
metal oxides.
where, M = Ni, Co, Cd and Zn
239-251 ºC
[M{C6H4(CH3CONH)COO}2(N2H4)]
-N2H4
[M{C6H4(CH3CONH)COO}2]
where, M = Ni and Co
[M{C6H4(CH3CONH)COO}2]
324-486 ºC
[MO]
where, M = Ni and Co and CoO = Co3O4
401 ºC
[Cd{C6H4(CH3CONH)COO}2)]
CdCO3
625-682 ºC
CdO
ZnO
350 ºC
[Zn{C6H4(CH3CONH)COO}2(N2H4)]
ZnCO3
553 ºC
100
90
80
70
60
50
40
30
20
12
10
8
6
4
2
100
200
300
400
500
600
700
Temperature (ºC
Fig. 4. TG-DTA of [Ni(2-acamb)2N2H4·2H2O
Fig. 7. SEM image of CoO obtained from [Co(2-acamb)2(N2H4).H2O
100
80
60
40
20
0
1000
900
800
700
600
500
400
300
200
100
10
8
6
4
2
0
200
400
600
800
0
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
keV
Temperature (ºC
Fig. 5. TG-DTA of [Cd(2-acamb)2N2H4·2H2O
Fig. 8. SEM-EDX picture of CoO
40
100
30
20
10
0
90
80
70
60
50
40
30
20
10
0
-10
-20
-30
100 150 200 250 300 350 400 450 500 0565
Temperature (ºC
Fig. 6. TG-DTA of [Zn(4-acamb)2(N2H4)]·2H2O
XRD-data of complexes: The powder XRD patterns with
their d-spacings are given in Table-4. They imply that each set
of complexes with similar composition possesses isomorphism
among them.
Fig. 9. SEM image of CdO obtained from [Cd(3-acamb)2(N2H4)].2H2O

214 Bai et al.
Asian J. Chem.
1000
900
800
700
600
500
400
300
200
100
0
1; M = Ni, Cd and Zn and x = 2 The NHCOCH3 group is both
larger and less strongly electron donating than the NH2 group
and hence has not involved in complexation.
The IR frequencies reveal the coordination of the hydra-
zine with metal and the coordination mode of the carboxylate
ion to metal. XRD patterns show isomorphism among the
complexes with similar molecular formulae. The SEM-EDS
studies confirm the formation of respective metal oxides. The
thermal data reveals that various steps of decomposition of
the compounds to form their metal oxide. The electronic spectra
and the magnetic susceptibility values reveal the coordination
and geometry. They suggest that Ni, Co, Cd and Zn complexes
possesses distorted octahedral geometry with coordination
number6. The proposed structures of these complexes are repre-
sented in the Figs. 13-15. However, they may be confirmed
by single crystal XRD only.
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
keV
Fig. 10. SEM-EDX picture of CdO
N2H4
O
O
O
O
C
C
M
· xH2O
NHCOCH3
H3COCHN
N2H4
Fig. 13. Proposed structures of transition metal complexes of 2-acetamido
benzoate with formula [M(2-acamb)2(N2H4)].xH2O, where M = Ni
and x = 2; M = Co, Cd, Zn and x = 1
Fig. 11. SEM image of ZnO obtained from [Zn(4-acamb)2.N2H4]2H2O
1000
900
800
700
600
500
400
300
200
100
N2H4
O
O
O
O
C
C
M
· xH2O
NHCOCH3
H3COCHN
N2H4
Fig. 14. Proposed structures of transition metal complexes of 3-acetamido
benzoate with formula [M(3-acamb)2(N2H4)].xH2O, where M = Ni,
Co and x = 1; M = Co, Cd, Zn and x = 2
0
0.00 1.00 2.00 3.00 4.00 5.00 6.00 7.00 8.00 9.00 10.00
keV
Fig. 12. SEM-EDX picture of ZnO
N2H4
O
O
O
O
Conclusion
H3COCHN
C
C
NHCOCH3
M
· xH2O
All the three isomeric acetamido benzoic acids have
formed two categories of hydrated neutral hydrazine complexes
with the formulae [M{(2-),(3-) and (4-) acamb)}2 (N2H4)].xH2O
where 2-acambH = 2-acetamido benzoic acid, M = Ni and x =
2; M = Co, Cd and Zn and x = 1, 3-acambH = 3-acetamido
benzoic acid, M = Ni, Co and x = 1; M = Cd and Zn and x = 2
and 4-acambH = 4-acetamido benzoic acid, M = Co and x =
N2H4
Fig. 15. Proposed structures of transition metal complexes of 4-acetamido
benzoate with formula [M(4-acamb)2(N2H4)].xH2O, where M = Ni,
Cd, Zn and x = 2; M = Co and x = 1

Vol. 25, No. 1 (2013)
Studies of Transition Metal Complexes of Acetamido Benzoic Acids with Hydrazine 215
TABLE-4
XRD DATA OF COMPLEXES (d-SPACING IN Å UNITS AND INTENSITY IN PARENTHESES)
[M(2-acamb)2N2H4].xH2O, (where M = Ni
and x = 2 and M=Co, Cd, Zn and x = 1)
2-acambH = 2-acetamido benzoic acid
[M(3-acamb)2N2H4.].xH2O, (where M = Ni,
Co and x = 1 and M = Cd, Zn and x = 2)
3-acambH = 3-acetamido benzoic acid
[M (4-acamb)2N2H4].xH2O, where M = Co and x
=1 and M = Ni, Cd, Zn and x = 2)
4-acambH = 4-acetamido benzoic acid
Ni
Co
Cd
Zn
Ni
Co
Cd
Zn
Ni
Co
Cd
Zn
15.30
(22.20)
13.30
(40.00)
10.12
22.34
(3.23)
11.37
(100.00)
10.25
(12.90)
9.19
(6.45)
7.12
(4.84)
6.47
(6.45)
20.17
(41.67)
11.11
20.57
(65.00)
10.45
21.92
(100.00)
12.44
13.79
(29.10)
10.51
11.35
(5.56)
9.46
(100.00)
9.05
(29.63)
7.48
(94.44)
6.05
(85.19)
5.77
9.43
(33.00)
11.30
(34.00)
(19.00)
(32.00)
(42.00)
(100.00) (100.00)
8.95
(38.20)
8.30
(45.50)
6.40
(54.50)
5.55
8.95
(15.56)
7.47
(35.56)
6.76
(4.44)
6.19
8.00
(10.00)
7.30
(8.33)
6.70
(20.00)
5.65
8.57
(68.00)
7.44
(100.00)
6.44
(19.00)
5.99
7.57
(50.00)
6.18
(12.00)
6.48
7.54
(13.00)
6.91
(9.00)
6.45
6.49
(98.3)
5.64
6.36
(47.00)
5.83
5.73
5.48
(32.70)
5.32
(40.00)
5.41
(29.00)
5.53
(18.52)
(71.19)
(71.67)
5.34
(30.00)
5.37
(10.00)
(100.00)
5.29
(22.00)
(36.00)
5.35
(38.20)
4.44
(5.50)
(37.78)
5.11
(35.56)
(22.58)
5.07
(16.67)
4.58
(30.00)
4.71
(15.00)
(100.00)
4.73
(48.33)
(63.00)
4.44
(58.00)
(15.00)
4.83
(58.20)
4.42
4.96
(29.63)
4.75
3.32
(87.50)
2.50
4.44
(31.00)
4.56
(38.00)
4.86
4.04
4.25
4.17
(17.78)
4.47
(2.20)
(3.23)
3.95
(3.23)
3.83
(29.63)
4.63
(33.33)
4.39
(100.00) (100.00)
(51.66)
3.96
(40.00)
(28.33)
3.93
(18.30)
(9.00)
4.11
(16.00)
3.95
3.98
(27.30)
3.42
3.78
(42.00)
3.31
3.71
(12.00)
3.32
4.13
3.73
3.69
3.65
(25.50)
(4.44)
3.96
(4.84)
3.72
(3.50)
4.13
(50.00)
3.40
(76.66)
3.42
(13.00)
(53.00)
(20.00)
3.10
(11.00)
3.66
(13.33)
3.59
(8.89)
3.41
(3.23)
3.56(6.45
)
(22.22)
4.05
(16.67)
(46.00)
3.17
(26.66)
2.92
(36.00)
3.17
(70.00)
3.07
(16.00)
2.84
(14.00)
(100.00)
3.40
(60.00)
2.81
(16.40)
2.63
(9.10)
2.50
(7.30)
2.38
3.39
3.94
3.11
(6.67)
3.11
(4.44)
(4.84)
3.21
(3.23)
3.06
(3.23)
(57.41)
3.87
(2.60)
3.76
(2.60)
3.67
(41.67)
2.89
(100.00)
2.81
(18.30)
(33.00)
2.91
(6.60)
2.83
(10.00)
(16.00)
2.99
(11.00)
2.84
(27.27)
2.75
2.66
(47.00)
2.60
2.89
2.72
2.59
(9.10)
(3.23)
(9.26)
3.39
(23.33)
2.60
(15.00)
2.48
(63.00)
2.54
(7.00)
2.58
(57.41)
3.35
(29.63)
(13.33)
2.44
(20.00)
2.24
(18.30)
2.24
(10.00)
2.19
(63.00)
2.30
(47.00)
(7.00)
2.40
(15.00)
3.25
2.14
2.28
(33.33)
3.17
(7.40)
(13.33)
2.17
(20.00)
2.09
(10.00)
2.04
(15.00)
1.85
(37.00)
2.05
(42.00)
(6.00)
2.22(9.00
)
1.90
(14.00)
2.90
1.97
2.17
(11.11)
2.84
(9.26)
(15.00)
2.03
(16.66)
1.96
(5.00)
1.80
(5.00)
1.61
(47.00)
1.91
(74.00)
(7.00)
2.05
(7.00)
1.89
2.49
1.84
(7.40)
2.36
(11.11)
(20.00)
1.87
(23.33)
1.79
(5.00)
(58.00)
1.73
(37.00)
(7.00)
1.82
(4.00)
1.77
2.22
(12.96)
2.18
(7.40)
(6.66)
1.67
(8.33)
1.61
(6.00)
1.65
(4.00)
1.55
1.98
(7.40)
(8.33)
(4.00)
1.56
(5.00)
1.52
1.55
(47.00)
1.46
1.45
(4.00)
(5.00)
(53.00)
1.45
(6.66)
1.42
(53.00)

216 Bai et al.
[M(2-acamb)2N2H4].xH2O, (where M = Ni
Asian J. Chem.
[M(3-acamb)2N2H4.].xH2O, (where M = Ni,
Co and x = 1 and M = Cd, Zn and x = 2)
3-acambH = 3-acetamido benzoic acid
[M (4-acamb)2N2H4].xH2O, where M = Co and x
=1 and M = Ni, Cd, Zn and x = 2)
and x = 2 and M=Co, Cd, Zn and x = 1)
2-acambH = 2-acetamido benzoic acid
4-acambH = 4-acetamido benzoic acid
Ni
Co
Cd
Zn
Ni
Co
Cd
Zn
Ni
Co
Cd
Zn
1.42
(5.00)
1.38
(42.00)
1.37
(32.00)
1.34
(42.00)
1.32
(32.00
1.29
(47.00)
1.27
(53.00)
1.25
(53.00)
1.22
(47.00)
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ACKNOWLEDGEMENTS
The authors acknowledged toAll India Council for Technical
education (AICTE) for granting the financial support for this
work (grant in aid No./8023/BOR/RID/RPS- 2, 2008-2009).
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