Copper(II) complexes of 1,2-DI(imino-4′-antipyrinyl)ethane and 4-N-(4′-antipyrylmethylidene)-aminoantipyrine

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COPPER(II) COMPLEXES OF 1,2-DI(IMINO-4′-
ANTIPYRINYL)ETHANE AND 4-N-(4′-
ANTIPYRYLMETHYLIDENE)AMINOANTIPYRINE
N. T. Madhu a & P. K. Radhakrishnan b
a School of Chemical Sciences, Mahatma Gandhi University, Priyadarshini Hills P.O.,
Kottayam, Kerala, 686 560, India
b School of Chemical Sciences, Mahatma Gandhi University, Priyadarshini Hills P.O.,
Kottayam, Kerala, 686 560, India
Version of record first published: 15 Feb 2007.
To cite this article: N. T. Madhu & P. K. Radhakrishnan (2001): COPPER(II) COMPLEXES OF 1,2-DI(IMINO-4′-
ANTIPYRINYL)ETHANE AND 4-N-(4′-ANTIPYRYLMETHYLIDENE)AMINOANTIPYRINE, Synthesis and Reactivity in Inorganic and
Metal-Organic Chemistry, 31:2, 315-330
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SYNTH. REACT. INORG. MET.-ORG. CHEM., 31(2), 315–330 (2001)
COPPER(II) COMPLEXES OF
1,2-DI(IMINO-4ꢀ-ANTIPYRINYL)ETHANE
AND 4-N-(4ꢀ-ANTIPYRYLMETHYLIDENE)-
AMINOANTIPYRINE
N. T. Madhu and P. K. Radhakrishnan∗
School of Chemical Sciences, Mahatma Gandhi University,
Priyadarshini Hills P.O., Kottayam-686 560, Kerala, India
ABSTRACT
Copper(II) complexes of the Schiff bases 1,2-di(imino-4ꢀ-anti-
pyrinyl)ethane (GA) and 4-N-(4ꢀ-antipyrylmethylidene)amino-
antipyrine (AA) have been synthesized and characterized by el-
emental analyses, electrical conductance in non-aqueous solvents,
infrared, electronic and EPR spectra as well as magnetic suscep-
tibility measurements. The complexes have the general formulae
[Cu(GA)]X2 (where X = ClO4 or NO3), [Cu(GA)X2] (where X
= Cl or Br), [Cu(AA)2]X2 (where X = ClO4, NO3 or Cl) and
[Cu(AA)Br]Br. GA acts as a neutral tetradentate ligand coordinat-
ing through both carbonyl oxygens and both azomethine nitrogens.
In the perchlorate and nitrate complexes of GA, both anions re-
main ionic while in the corresponding halide complexes both an-
ions are coordinated to the metal ion. AA acts as a neutral bidentate
ligand coordinating through one of the carbonyl oxygens and the
azomethine nitrogen in the perchlorate, nitrate and chloride com-
plexes, while the coordination of AA occurs in a neutral tridentate
∗Address correspondence to P. K. Radhakrishnan. E-mail: mgu@md2.vsnl.net.in
315
Copyright ꢁ 2001 by Marcel Dekker, Inc.
www.dekker.com
C

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MADHU AND RADHAKRISHNAN
fashion through both carbonyl oxygens and the azomethine nitro-
gen in the bromide complex. In the perchlorate, nitrate and chloride
complexes of AA both anions remain ionic, while in the bromide
complex, one of the bromides is coordinated to the metal ion. A
square-planar geometry is assigned around the Cu(II) ion in all
these complexes except the chloride and bromide complexes of
GA, which are of distorted-octahedral geometry.
INTRODUCTION
A number of workers have used antipyrine and its derivatives as ligands in
isolating solid complexes with 3d metal ions (1,2). Relatively little is known about
the Schiff base complexes of 4-aminoantipyrine with transition metal ions (3). In
viewofthis, andaspartofourearlierinvestigationsonSchiffbase-metalcomplexes
(4–6), we report here the synthesis and characterization of two new series of Cu(II)
complexes of the ligands 1,2-di(imino-4ꢀ-antipyrinyl)ethane (GA) (Fig. 1) and
4-N-(4ꢀ-antipyrylmethylidene)aminoantipyrine (AA) (Fig. 2). Antipyrine and its
derivatives possess antibacterial and anti-inflammatory properties and, hence, the
present complexes may be of physiological importance (7,8).
RESULTS AND DISCUSSION
The formation of the complexes may be represented by the general equations
shown below.
CuX2 + GA → Cu(GA)X2 (where X = ClO4, NO3, Cl or Br)
CuX2 + 2AA → Cu(AA)2X2 (where X = ClO4, NO3 or Cl)
CuBr2 + AA → Cu(AA)Br2
H
C
H
C
CH3
H3C
C
C
C
C
N
N
N
C
N
C
N
N
O
O
CH3
H3C
Figure 1. 1,2-Di(imino-4ꢀ-antipyrinyl)ethane.

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317
H
CH3
N
H3C
C
C
C
C
C
2
C1
C
N
N
N
N
H3C
CH3
O
O
Figure 2. 4-N-(4ꢀ-Antipyrylmethylidene)aminoantipyrine.
The elemental analyses data (Table I) of the complexes suggest that the
present complexes may be formulated as Cu(GA)X2 (where X = ClO4, NO3, Cl
or Br), Cu(AA)2X2 (where X = ClO4 , NO3 or Cl) and Cu(AA)Br2.
The molar conductance values of the complexes of GA (Table II) in ace-
tonitrile, DMF and nitrobenzene (10−3 M solutions) are in the range expected for
1:2 electrolytes for the perchlorate and nitrate complexes while the correspond-
ing chloride and bromide complexes behave as non-electrolytes (9). Thus, the
complexes may be formulated as [Cu(GA)]X2 (where X = ClO4 or NO3) and
[Cu(GA)X2] (where X = Cl or Br).
The molar conductance values of the complexes of AA (Table II) in acetoni-
trile, DMF and nitrobenzene (10−3 M solutions) are in the range expected for 1:2
electrolytes except the bromide complex which shows a 1:1 electrolytic nature (9).
Thus the complexes may be formulated as [Cu(AA)2]X2 (where X = ClO4 , NO3
or Cl) and [Cu(AA)Br]Br.
Infrared Spectra
GA Complexes
The important infrared spectral data of GA and its complexes are presented
in Table III. The strong band at 1650 cm−1 due to the C O stretching vibra-
==
tion of GA is shifted to the region 1620–1625 cm−1 in the complexes, indicat-
ing coordination of both carbonyl oxygens (4). The strong band at 1576 cm−1
==
attributable to the C N stretching vibration of GA is shifted to the region 1520–
1522 cm−1 in the complexes, indicating coordination of both azomethine nitrogens
(10).
In the perchlorate complex an intense, unsplit band at 1085 cm−1 and a
medium band at 625 cm−1 are observed which are attributed to the ν3 and ν4
vibrations, respectively, of uncoordinated perchlorate (Td) ion (11).

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MADHU AND RADHAKRISHNAN

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319
Table II. Molar Conductance Data of the Copper(II)
Complexes of GA and AA (in ohm−1 cm2 mol−1
)
Molar Conductancea
Complex
C6H5NO2 CH3CN
DMF
[Cu(GA)](ClO4)2
[Cu(GA)](NO3)2
[Cu(GA)Cl2]
53.0
51.1
8.2
232.6
220.16
77.50
144.04
132.96
50.6
[Cu(GA)Br2]
6.2
99.72
56.5
[Cu(AA)2](ClO4)2
[Cu(AA)2](NO3)2
[Cu(AA)2]Cl2
51.09
50.60
45.76
29.21
258.03
243.42
221.16
150.92
131.44
126.58
135.70
77.89
[Cu(AA)Br]Br
a10−3 M solutions used.
In the nitrate complex, the strong band at 1380 cm−1 and a medium band at
820 cm−1 are attributed to the ν3 and ν2 vibrations of uncoordinated nitrate (D3h)
ion (12).
In the far-infrared spectra of the chloride and bromide complexes, the Cu-Cl
and Cu-Br stretching vibrations are at 308 and 233 cm−1 respectively (13) which
are absent in the spectrum of the free ligand. Further, the Cu-O and Cu-N stretching
vibrations occur at about 550 and 460 cm−1, respectively, in the spectra of all of
the complexes (14,15).
The above results are in conformity with the conductance data that both chlo-
rides and both bromides are coordinated to the metal ion while both perchlorates
and both nitrates remain as counter ions in these complexes.
Table III. Important Infrared Spectral Bands (cm−1) of GA and Its Copper(II) Complexesa
GA
[Cu(GA)](ClO4)2 [Cu(GA)](NO3)2 [Cu(GA)Cl2] [Cu(GA)Br2] Assignment
==
ν(C O)
1650 s
1576 s
1620 s
1522 s
1085 s
625 m
–
–
–
–
1620 s
1520 s
–
1625 s
1522 s
–
–
–
–
308 m
–
555 w
460 w
1620 s
1522 s
–
–
–
–
–
233 w
550 w
465 w
==
ν(C N)
–
–
–
–
–
–
–
–
ν3-ionic ClO4
ν4-ionic ClO4
ν3-ionic NO3
ν2-ionic NO3
–
1380 s
820 m
–
–
ν(Cu Cl)
–
ν(Cu Br)
–
–
550 w
460 w
550 w
460 w
ν(Cu O)
–
ν(Cu N)
as = Strong; m = medium; w = weak.

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MADHU AND RADHAKRISHNAN
AA Complexes
The important infrared spectral data of AA and its complexes are presented
in Table IV. AA exhibits two strong bands at 1643 and 1659 cm−1 which are at-
1==
2==
tributed to the C O and C O stretching vibrations, respectively (6,10) (Fig. 2).
−1
1==
In the complexes ν(C O) band of AA is shifted to about 1628 cm in the per-
chlorate, nitrate and chloride complexes indicating the coordination of the oxygen
1==
2==
(4) of C O. However, the band corresponding to ν(C O) remains practically
unaltered at 1656–1660 cm−1, indicating the non-coordination of the oxygen (10)
2==
1==
2==
of C O. But in the bromide complex, the C O and C O stretching vibra-
tions are shifted to 1629 and 1645 cm−1, respectively, indicating the coordination
of both carbonyl oxygens of AA (4). Further, the strong band at 1596 cm−1 at-
−1
==
tributable to C N stretching vibration of AA (16) is shifted to 1606–1608 cm
in all the complexes indicating the coordination of the azomethine nitrogen also
(17).
In the perchlorate complex, the bands at 1085 and 624 cm−1 are attributed
to the ν3 and ν4vibrations of uncoordinated perchlorate of Td symmetry
(11).
In the nitrate complex, a strong band at 1385 cm−1 and a medium band at
830 cm−1 are due to the ν3 and ν2 vibrations of uncoordinated nitrate ion of D3h
symmetry (12).
In the far-infrared spectrum of the bromide complex, the Cu-Br stretching
vibration occurs (13) at 290 cm−1 which is absent in the spectrum of the ligand.
–
–
Further, the ν(Cu O) and ν(Cu N) stretching vibrations are observed at about 550
and 460 cm−1, respectively, in all the complexes (14,15).
Table IV. Important Infrared Spectral Bands (cm−1) of AA and Its Copper(II) Complexesa
[Cu(AA)2] [Cu(AA)2]
AA
(ClO4)2
(NO3)2
[Cu(AA)2]Cl2 [Cu(AA) Br]Br
Assignment
1==
ν(C O)
1643 s
1659 s
1596 s
–
–
–
–
–
–
–
1628 s
1656 s
1608 s
1085 s
624 m
–
1629 s
1656 s
1606 s
–
1630 s
1660 s
1606 s
–
–
–
–
–
1629 s
1645 s
1606 s
–
–
–
ν(C O)
2==
==
ν(C N)
ν3–ionic ClO4
ν4–ionic ClO4
ν3–ionic NO3
ν2–ionic NO3
–
1385 s
830 m
–
555 w
460 w
–
–
–
–
290 m
550 w
455 w
ν(Cu Br)
–
ν(Cu O)
550 w
460 w
550 w
455 w
–
ν(Cu N)
as = strong; m = medium; w = weak.

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321
The above results are in conformity with the conductance data that both per-
chlorates and both nitrates remain ionic and one of the bromide ion is coordinated
to the metal ion in these complexes.
Electronic Spectra
GA Complexes
The electronic spectral bands of GA and its complexes with their tentative
assignments are presented in Table V. In the complexes, both n → π∗ and π → π∗
bands are found as blue-shifted to the regions 26,385–26,737 cm−1 and 43,859–
45,045 cm−1, respectively, compared to that of GA. The broad structured band
around 18,382 cm−1 in the perchlorate complex and around 18,761 cm−1 in the ni-
2
trate complex is in accordance with the 2B1g → B2g transition indicating a square-
planar geometry around the copper(II) ion (18,19). For the halide complexes, the
broad band around 21,881 cm−1 in the chloride complex and around 19,723 cm−1
in the bromide complex indicate a tetragonal configuration around the copper(II)
Table V. Electronic Spectral Data and Magnetic Moments of the Copper(II) Complexes
of GA
Compound
GA
Abs. Max. (cm−1
)
Tentative Assignments
µeff (BM)
26180
39220
n → π∗
π → π∗
—
[Cu(GA)](ClO4)2
[Cu(GA)](NO3)2
[Cu(GA)Cl2]
26737
44247
35842
18382
n → π∗
1.89
2.19
1.76
1.73
π → π∗
Charge transfer
2
2B1g → B2g
26618
45045
36496
18761
n → π∗
π → π∗
Charge transfer
2B1g
→
2B2g
26525
43859
36363
21881
n → π∗
π → π∗
Charge transfer
d-d transitions
[Cu(GA)Br2]
26385
45045
36231
19723
n → π∗
π → π∗
Charge transfer
d-d transitions

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MADHU AND RADHAKRISHNAN
Table VI. Electronic Spectral Data and Magnetic Moments of the Copper(II) Complexes
of AA
Compound
AA
Abs. Max. (cm−1
)
Tentative Assignments
µeff (BM)
28570
40485
n → π∗
π → π∗
—
[Cu(AA)2](ClO4)2
[Cu(AA)2](NO3)2
[Cu(AA)2]Cl2
24330
40160
33333
14367
n → π∗
1.71
2.12
1.88
1.75
π → π∗
Charge transfer
2
2B1g → A1g
25125
40160
33444
14450
n → π∗
π → π∗
Charge transfer
2
2B1g → A1g
24213
39840
34843
15384
n → π∗
π → π∗
Charge transfer
2
2B1g → A1g
[Cu(AA)Br]Br
24271
39840
34246
16155
n → π∗
π → π∗
Charge transfer
2
2B1g → A1g
ion (20). Further, the spectra of all complexes exhibit an intense absorption band in
the region 35,842–36,496 cm−1, which might be due to charge transfer processes.
AA Complexes
The electronic spectral bands of AA and its complexes with their tenta-
tive assignments are presented in Table VI. In the complexes, both n → π∗ and
π → π∗ bands are found to be red-shifted to the region 24,213–25,125 cm−1 and
39,840–40,160 cm−1, respectively, compared to that of AA. The broad band around
2
14,367-16,155 cm−1 in the present complexes is attributed to the 2B1g → A1g tran-
sition, consistent with a square-planar geometry around the copper(II) ion (21,22).
Further, the spectra of all of the complexes exhibit an intense absorption band in
the region 33,333–34,843 cm−1, which might be due to charge transfer processes.
EPR Spectra
X-band EPR spectra of the complexes of GA and AA were recorded in
1:1 methanol-toluene at liquid nitrogen temperature (Figs. 3 and 4). The various

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323
Figure 3. EPR spectra of copper(II) complexes of GA: A = [Cu(GA)](ClO4)2,
B = [Cu(GA)](NO3)2, C = [Cu(GA)Cl2], and D = [Cu(GA)Br2].
Figure 4. EPR Spectra of copper(II) complexes of AA: A = [Cu(AA)2](ClO4)2,
B = [Cu(AA)2](NO3)2, C = [Cu(AA)2]Cl2, and D = [Cu(AA)Br]Br.

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MADHU AND RADHAKRISHNAN
Table VII. EPR Parameters of Copper(II) Complexes of GA and AA in 1:1 Methanol-
Toluene at Liquid Nitrogen Temperature
Complex
g
g
A
ꢂ
A
⊥
gav
ꢂ
⊥
[Cu(GA)](ClO4)2
[Cu(GA)](NO3)2
[Cu(GA)Cl2]
2.40
2.39
2.40
2.40
2.38
2.37
2.37
2.37
2.16
2.16
2.15
2.15
2.08
2.10
2.09
2.08
111.66
108.33
113.33
108.33
143.33
140.00
140.00
146.66
43.33
46.66
50.00
46.66
36.66
32.50
41.66
45.00
2.24
2.23
2.23
2.23
2.18
2.19
2.18
2.17
[Cu(GA)Br2]
[Cu(AA)2](ClO4)2
[Cu(AA)2](NO3)2
[Cu(AA)2]Cl2
Cu(AA)Br]Br
parameters were computed from the spectra using the DPPH free radical as the ‘g’
marker. All the complexes have a well resolved g and a broadened g region. In
ꢂ
⊥
all of the spectra, no superhyperfine splitting from the ligand is observed.
The various calculated parameters are presented in Table VII. The trend
g > g > 2.0023, observed for these complexes, show that the unpaired electron
ꢂ
⊥
2
2
is localized in the dx −y orbital (23). Further, the shape of the EPR spectra indicate
that the geometry around the Cu(II) ions is square-planar in the perchlorate and
nitrate complexes of GA and in all of the complexes of AA and an elongated
octahedron in the chloride and bromide complexes of GA. This observation is
supported by the less-intense peaks on the low-field side and high-intense peaks
on the high-field side (24).
Magnetic Moment Data
The molar magnetic moments of the complexes of GA and AA are presented
in Tables V and VI. The magnetic moments of the present copper(II) complexes
vary in the range 1.71–2.19 BM. This indicates that the complexes are monomeric
in nature and that any metal-metal interaction is absent in these complexes (24).
Based on the results of the present study, the structures shown in Figs. 5 and
6 may be assigned to the complexes.
EXPERIMENTAL
Materials
The metal salts, Cu(ClO4)2 · 6H2O, Cu(NO3)2 · 6H2O, CuCl2 · 2H2O and
CuBr2 · 4H2O, werepreparedfromAnalarBDHcoppercarbonateandtherespective
50%acidsandcrystallizingoutthesaltsbyevaporatingthesolutiononasteambath.

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325
H
C
H
C
N
N
H3C
CH3
C
C
C
C
Cu
X2
C
N
C
N
N
N
O
O
H3C
CH3
C6H5
C6H5
X = C1O4 or NO3
H
C
H
C
N
N
X
Cu
X
H3C
CH3
C
C
C
C
C
N
C
N
N
N
O
O
H3C
CH3
C6H5
C6H5
X = C1 or Br
Figure 5. Tentative structures of Cu(II) complexes of GA.
Preparation of the Ligands
The ligands 1,2-di(imino-4ꢀ-antipyrinyl)ethane (GA) and 4-N-(4ꢀ-antipyryl-
methylidene)aminoantipyrine (AA) were prepared and characterized as reported
earlier (5).

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MADHU AND RADHAKRISHNAN
H5C6
O
H3C
H
N
C2
C
CH3
C
N
N
H3C
N
C
C
C
N
1
C
C6H5
H3C
O
H5C6
Cu
N
O
X2
1
N
C
CH3
N
C
C
H
C
H3C
CH3
C
C
2
C
N
CH3
N
C6H5
O
( X = ClO4, NO3 or Cl)
CH3
C
CH3
C
H3C
H
N
N
CH3
C
N
C
C
N
1
2
C
Br
C
N
H5C6
C6H5
O
Cu
Br
O
Figure 6. Tentative structures of Cu(II) complexes of AA.
Preparation of GA Complexes
One mmol of Cu(ClO4)2 · 6H2O (0.3703 g), Cu(NO3)2 · 6H2O (0.2416 g),
CuCl2 · 2H2O (0.1704 g) or CuBr2 · 4H2O (0.2233 g) in methanol (10 mL) was

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327
added to a boiling suspension of 1.2 mmol of GA (0.4294 g) in ethyl acetate
(100 mL). This mixture was refluxed for about 2 h on a water bath. The precipitated
complex was filtered and washed several times with hot ethyl acetate to remove the
excess ligand. The dark brown complex was then recrystallized from acetonitrile
and dried under vacuum over phosphorus(V) oxide.
Preparation of AA Complexes
Perchlorate, Chloride, and Bromide Complexes
One mmol of Cu(ClO4)2 · 6H2O (0.3703 g), CuCl2 · 2H2O (0.1704 g) or
CuBr2 · 4H2O (0.2233 g) in methanol (10 mL) was added to a boiling suspension of
1.2 mmol of AA (0.4817 g) for the bromide complex and 2.2 mmol of AA (0.8830
g) for the perchlorate and chloride complexes in ethyl acetate (100 mL). This
mixture was refluxed for about 2 h on a steam bath. The precipitated complex was
filtered and washed several times with hot chloroform to remove the excess ligand.
The brownish yellow complex was then recrystallized from methanol and dried
under vacuum over phosphorus(V) oxide.
Nitrate Complex
One mmol of Cu(NO3)2 · 6H2O (0.2416 g) in acetone (10 mL) was added to
a boiling suspension of 2.2 mmol of AA (0.8830 g) in acetone. Then the complex
was separated by the same procedure as described above.
Physical Methods of Analysis
All the complexes were analyzed for metal and halide contents by standard
methods (25) and the perchlorate content by the Kurz method (26). The electrical
conductance of the complexes in nitrobenzene, DMF and acetonitrile (10−3
M
solutions) were measured at room temperature using a Toshniwal conductivity
bridge with a dip-type conductance cell (cell constant 0.9737). The infrared spectra
of the ligands and the complexes were recorded in the range 4000–400 cm−1 on a
Shimadzu IR 470 spectrophotometer in KBr disc and in the range 400–200 cm−1 on
a Perkin Elmer 983 IR spectrophotometer in polyethylene powder. The electronic
spectra of the ligands and the complexes in the solid state (paste with Nujol) were
measured in the range 200–1100 nm on a Shimadzu UV 160 A spectrophotometer.
The EPR spectra of the complexes were recorded in methanol-toluene (1:1) at
liquid nitrogen temperature using a Varian E-112 EPR spectrophotometer. The

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MADHU AND RADHAKRISHNAN
elemental analyses (C, H and N) were carried out on a Heraeus CHNO rapid
analyzer. The magnetic moments were measured at room temperature by the Gouy
method using mercury(II)tetrathiocyanatocobaltate(II) as the calibrant.
ACKNOWLEDGMENTS
We thank the Heads of the Regional Sophisticated Instrumentation Cen-
tre, Indian Institute of Technology, Chennai and Indian Institute of Technology,
Mumbai, for some instrumental analyses. We also thank the Mahatma Gandhi
University, Kerala, India, for the award of a Junior Research Fellowship to one of
us (NTM).
REFERENCES
1. Bailey, R. A.; Peterson, T. R. Complexes of Co(II), Ni(II)and Zn(II) with
Pyrazolone Ligands. Can. J. Chem. 1969, 47, 1681–1687.
2. Nair, M. R. G.; Prabhakaran, C. P. Copper(II) and Nickel(II) Complexes
of 1-Phenyl-2,3-dimethyl-4-(2-hydroxynaphthylazo)-5-pyrazolone. J. Inorg.
Nucl. Chem. 1981, 43(12), 3390–3393.
3. Radhakrishnan, T.; Jospeh, P. T.; Prabhakaran, C. P. Copper(II) Complexes
of Salicylal-4-aminoantipyrine and 2-Hydroxy Naphthal-4-aminoantipyrine.
J. Inorg. Nucl. Chem. 1976, 38, 2217–2220.
4. Radhakrishnan, P. K.; Indrasenan, P.; Nair, C. G. R. Complexes of Lanthanide
Nitrateswith4-N-(2ꢀ-HydroxyBenzylidene)-Amionoantipyrine. Polyhedron
1984, 3(1), 67–70.
5. Madhu, N. T.; Radhakrishnan, P. K. Complex of Nickel(II) with 1,2-
Di(imino-4ꢀ-antipyrinyl)ethane and 4-N-(4ꢀ-Antipyrylmethylidene)amino-
antipyrine. Synth. React. Inorg. Met.-Org. Chem. 2000, 30(8), 1561–1579.
6. Joseph, S.; Radhakrishnan, P. K. Yttrium and Lanthanide Perchlorate Com-
plexes of N,Nꢀ-Bis(4-antipyrylmethylidene)ethylenediamine. Synth. React.
Inorg. Met.-Org. Chem. 1998, 28(3), 423– 435.
7. Singh, L.; Mohan, G.; Parashar, R. K.; Tripathi, S. P.; Sharma, R. C. Studies
on Anti-inflammatory Activity of Some Lanthanone Complexes of Bioactive
Organic Molecules. Curr. Sci. 1986, 55, 846–848.
8. Wang, P. H.; Keck, E. J.; Lein, E. J.; Lai, M. C. C. Design, Synthesis, Testing
and Quantitative Structure-Activity Relationship Analysis of Substituted Sal-
icylaldehyde Schiff bases of 1-Amino-3-hydroxyguanidine Tosylate as New
Antiviral Agents against Coronavirus. J. Med. Chem. 1990, 33, 608–614.
9. Geary, W. J. The Use of Conductivity Measurements in Organic Solvents for
the Characterisation of Coordination Compounds. Coord. Chem. Rev. 1971,
7, 81–22.

ORDER
REPRINTS
COPPER(II) COMPLEXES
329
10. Alice, C. J.; Prabhakaran, C. P. Palladium(II) Complexes of Schiff bases De-
rived from 5-Amino-2,4-(1H,3H)pyrimidinedione(5-Aminouracil) and 1,2-
Dihydro-1,5-dimethyl-2-phenyl-4-amino-3H-pyrazol-3-one.Transition Met.
Chem. 1990, 15, 449–453.
11. Scholer, R. P.; Merbach, A. E. Raman and Infrared Study of Hexamthylphos-
phoramide Complexes of Lanthanide Perchlorates. Inorg. Chim. Acta 1975,
15, 15–20.
12. Gatehouse, B. M.; Livingstone, S. E.; Nyholm, R. S. Infrared Spectra of
Some Nitrato and other Oxy-anion Coordination Complexes. J. Inorg. Nucl.
Chem. 1958, 8, 75–78.
13. Nakamoto, K. Coordination Compounds. In Infrared and Raman Spectra of
Inorganic and Coordination Compounds, 4th Ed.; John Wiley and Sons, Inc.:
New York, 1986; 197–199.
14. Donia, A. M.; El-Saied, F. A. Complexes of Manganese(II),Cobalt(II) and
Nickel(II) with the Keto form of Some Antipyrine Schiff base Derivatives.
Polyhedron 1988, 7(21), 2149–2153.
15. Naik, H. S. B.; Siddaramaiah; Ramappa, P. G. Thermal Degradation Kinetics
of Cobalt(II)-Doxepin Complexes. Thermochim. Acta 1996, 287, 279–286.
16. Silverstein, R. M.; Bassler, G. C.; Morril, T. C. Infrared Spectroscopy. In
Spectrometric Identification of Organic Compounds, 5th Ed.; John Wiley
and Sons, Inc.: New York, 1991; 93.
17. Liu Guofa; Na Chongwu; Li Bin; Mao Kunyuan. Complexes of Lanthanide
Nitrates with a Schiff base derived from o-Vanillin and p-Toluidine. Polyhe-
dron 1990, 9, 2019–2022.
18. Lever, A. B. P. Electronic Spectra of dn Ions. In Inorganic Electronic Spec-
troscopy, 2nd Ed.; Elsevier: Amsterdam, 1984; 570.
19. Misra, S.; Dubey, B. L.; Bahel, S. C. Synthesis, Characterization and Bio-
logical Activity of Co(II), Ni(II), Cu(II) and Zn(II) Complexes with Mer-
captooxadiazole. Synth. React. Inorg. Met.-Org. Chem. 1994, 24(6), 1027–
1042.
20. Sreekala, R.;Yusuff, K. K. M. Synthesis, CharacterisationandCytotoxicityof
New Complexes of Cobalt(II), Nickel(II) and Copper(II) with Quinoxaline-2-
Carboxaldehyde Thiosemicarbazone. Synth. React. Inorg. Met.-Org. Chem.
1994, 24(10), 1773–1788.
21. Usha; Chandra, S. Synthesis and Characterization of Co(II), Ni(II), Cu(II)
and Zn(II) Complexes of Some Thiosemicarbazones. Synth. React. Inorg.
Met.-Org. Chem. 1992, 22(7), 929–940.
22. Sakata, K.; Taziri, H; Yamaura, F.; Hashimoto, M. Studies on Tetraaza[14]
Tetraene Complexes of Nickel(II) and Copper(II). Synth. React. Inorg. Met.-
Org. Chem. 1990, 20(6), 757–771.
23. Singh, B.; Yadava, B. P.; Aggarwal, R. C. Synthesis and Characterization of 1-
Phenyl-5-benzol-4-thiobiuret Complexes with Oxovanadium(IV), Cobalt(II

ORDER
REPRINTS
330
MADHU AND RADHAKRISHNAN
and III), Nickel(II), Copper(II), Cadmium(II) and Mercury(II). Indian J.
Chem. 1984, 23A, 441–444.
24. Shetti, S. N.; Murty, A. S. R.; Tembe, G. L. Synthesis and Spectral Charac-
terization of Copper(II) Complexes of Dithiosemicarbazone. Indian J. Chem.
1993, 32A, 318–322.
25. Bassett, J.; Denney, R. C.; Jeffery, G. H.; Mendham, J. Titrimetric Analysis.
In Vogel’s Text Book of Quantitative Inorganic Analysis, 5th Ed.; ELBS:
London, 1961; 341, 379.
26. Kurz, E.; Kober, G.; Berl, M. Determination of Perchlorates by Fusion with
Nitrite. Anal. Chem. 1958, 30(12), 1983–1986.
Received August 17, 2000
Accepted December 8, 2000
Referee I: A. I. Odom
Referee II: T. S. Barnard

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