Synthesis, spectroscopic, thermal, and photostability studies of 2-aminobenzaldehyde phenylhydrazone (2ABPH) as fluorescent dye and their Cu(II), Co(II), and Mn(II) complexes

Article abstract of DOI:10.1080/15533174.2011.555863

Herein, the 2-aminobenzaldehyde phenylhydrazone (2ABPH) Schiff base and their mononuclear Mn(II), Co(II), and Cu(II) complexes were reported. The structures of the complexes have been elucidated by elemental analysis, molar conductivity, magnetic properties, infrared, electronic, mass spectra, and thermal studies. The stoichiometries of the 2ABPH complexes accordance of the mentioned analysis give the general formula [M(2ABPH)₂(Cl) ₂]·xH₂O (where M is Mn(II), Co(II), Cu(II), and x = 1, 4 and 6). The photo stabilities of the Schiff base and their complexes were examined. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/15533174.2011.555863

This article was downloaded by: [Nipissing University]
On: 17 October 2014, At: 12:27
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer
House, 37-41 Mortimer Street, London W1T 3JH, UK
Synthesis and Reactivity in Inorganic, Metal-Organic,
and Nano-Metal Chemistry
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/lsrt20
Synthesis, Spectroscopic, Thermal, and
Photostability Studies of 2-aminobenzaldehyde
Phenylhydrazone (2ABPH) as Fluorescent Dye and
their Cu(II), Co(II), and Mn(II) Complexes
Moamen S. Refat a b , Hamada M.A. Killa c , Asmaa F. Mansour d & Hammad Fetooh c
a Department of Chemistry, Faculty of Science , Port Said University , Port Said, Egypt
b Department of Chemistry, Faculty of Science , Taif University , Taif, Kingdom Saudi
Arabia
c Department of Chemistry, Faculty of Science , Zagazig University , Zagazig, Egypt
d Department of Physics, Faculty of Science , Zagazig University , Zagazig, Egypt
Published online: 12 Apr 2011.
To cite this article: Moamen S. Refat , Hamada M.A. Killa , Asmaa F. Mansour & Hammad Fetooh (2011) Synthesis,
Spectroscopic, Thermal, and Photostability Studies of 2-aminobenzaldehyde Phenylhydrazone (2ABPH) as Fluorescent
Dye and their Cu(II), Co(II), and Mn(II) Complexes, Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal
Chemistry, 41:3, 295-308
To link to this article: http://dx.doi.org/10.1080/15533174.2011.555863
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of
the Content. Any opinions and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied
upon and should be independently verified with primary sources of information. Taylor and Francis shall
not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other
liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 41:295–308, 2011
Copyright © Taylor & Francis Group, LLC
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533174.2011.555863
Synthesis, Spectroscopic, Thermal, and Photostability
Studies of 2-aminobenzaldehyde Phenylhydrazone (2ABPH)
as Fluorescent Dye and their Cu(II), Co(II), and Mn(II)
Complexes
Moamen S. Refat,1,2 Hamada M. A. Killa,3 Asmaa F. Mansour,4
and Hammad Fetooh3
1Department of Chemistry, Faculty of Science, Port Said University, Port Said, Egypt
2Department of Chemistry, Faculty of Science, Taif University, Taif, Kingdom Saudi Arabia
3Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt
4Department of Physics, Faculty of Science, Zagazig University, Zagazig, Egypt
of their donor atoms.[19−21] Schiff base complexes of trivalent
Herein, the 2-aminobenzaldehyde phenylhydrazone (2ABPH)
Schiff base and their mononuclear Mn(II), Co(II), and Cu(II)
complexes were reported. The structures of the complexes have
been elucidated by elemental analysis, molar conductivity, mag-
netic properties, infrared, electronic, mass spectra, and ther-
mal studies. The stoichiometries of the 2ABPH complexes ac-
cordance of the mentioned analysis give the general formula
[M(2ABPH)2(Cl)2].xH2O (where M is Mn(II), Co(II), Cu(II), and
x = 1, 4 and 6). The photo stabilities of the Schiff base and their
complexes were examined.
lanthanide ions have an important role in the development of
photonic light converting device and sensors,[22,23] sensitizer for
photodynamic therapy, and biomedical diagnostics,[24,25] among
others, show that extensive work with Schiff base complexes
has been done and is still in progress. In view of these findings
and in continuation to the authors’ previous work on the Schiff
bases,[26−31] this piece of work has been devoted with the aim
to synthesize some Mn(II), Co(II), and Cu(II) complexes with
2-aminobenzaldehyde phenylhydrazone (2ABPH) Schiff base
ligand, and examine their physical properties (photo stability of
the Schiff base before and after complexation) involving spectral
behaviors.
Keywords 2-aminobenzaldehyde phenylhydrazone, photo stabili-
ties, Schiff base, thermal studies
INTRODUCTION
MATERIALS AND METHODS
2-aminobenzaldehyde phenylhydrazone, C13H13N3; (MW =
211.27), is called Nitrin. It was prepared by refluxing 2-
nitrobenzaldehyde with phenylhydrazine.[1] This compound is
used in the detection of nitrites and colibacilli in urine.[2]
A large number of publications,[3−10] ranging from purely
synthetic to modern physicochemical and biochemically rel-
evant studies of metal complexes of Schiff bases, reveal
that such complexes have occupied a central role in the de-
velopment of coordination chemistry. These complexes have
been studied toward the behavior,[11] their coordination,[12−14]
stoichiometry,[15] and antibacterial activity.[16−18] Schiff bases
have been widely discussed due to their selective chelation to
certain metal ions depending on the number, kind, and position
The general chemical structure of the synthesized of 2-
aminobenzaldehyde phenyl hydrazone (2ABPH) is given in
(Figure 1).
Synthesized 2-aminobenzaldehyde Phenylhydrazone
(2ABPH)
To 100 ml of distilled water in a 250 ml beaker are added
1 g. of crystalline sodium sulfide nonahydrate and 0.5 gm of
sulfur. The mixture is heated on a water bath for 15–20 minutes
with occasional stirring, and then poured into a 500 ml round-
bottomed flask containing a hot solution of (3.02 g, 0.02 mol) of
o-Nitrobenzaldehyde and (2.20 ml, 0.02 mol) phenyl hydrazine
in 100 ml of methanol. A reflux condenser is attached, and the
mixture is heated under reflux for 3 hours. The solution is rapidly
chilled in an ice bath with occasional vigorous shaking and
stirring to induce crystallization. After 2 hours in the ice bath,
the deep red crystals of 2-aminobenzaldehyde phenylhydrazone
are collected on a Bu¨chner funnel and washed with 50 ml of
Received 17 July 2010; accepted 31 October 2010.
Address correspondence to Moamen S. Refat, Department of Chem-
istry, Faculty of Science, Port Said University, Port Said, Egypt. E-mail:
msrefat@yahoo.com
295

296
M. S. REFAT ET AL.
ice water to remove sodium sulfide. The product is immediately Mn(II) complexes isolated as powered materials. At the time
placed in a vacuum desiccator over solid calcium chloride pellets of addition: with respect to Co(II)/2ABPH complex, the color
for 24 hours. Re-crystallization was carried out in methanol. of solution before precipitation was yellowish-orange and af-
The yield of 2-aminobenzaldehyde phenylhydrazone produced ter precipitated, became greenish-brown ppt, the m.p = 136◦C
is 75% with m.p = 130◦C. The procedures of the synthesized and % yield = 0.321g (89%), for Mn(II)/2ABPH complex, the
of (2ABPH) described as follows:
color of complex before precipitation was orange-yellow and so
orange-yellow ppt was formed, with m.p = 134◦C and % yield
= 0.241g (71%). On the other hand, concerning Cu(II)/2ABPH
complex, the color of solution before precipitation process was
faint-yellow and turned to dark-green ppt complex with m.p =
136◦C, % yield = 0.309 g (97.5%).
NH NH2
CHO
H2N
NO2
CH
N
Methanol
Na2S
Microanalytical Techniques
Carbon, hydrogen, and nitrogen contents were determined
using a Perkin-Elmer CHN 2400. The copper(II), cobalt(II),
and manganese(II) contents were determined gravimetrically
by the direct ignition of the complexes at 1000◦C for 3 hours
till constant weight in the forms of metal oxides.
HN
Spectroscopic Investigations
IR spectra were recorded on Bruker FTIR Spectrophotometer
(4000–400 cm−1) in KBr pellets. The UV–vis, spectra were stud-
ied in the DMSO solvent with concentration (1.0 × 10−4 M) for
the 2-aminobenzaldehyde phenyl hydrazone (2ABPH) and their
complexes by help of Jenway 6405 Spectrophotometer with 1cm
quartz cell, in the range 800–200 nm. The solid reflectance spec-
tra were performed on a Shimadzu 3101pc spectrophotometer.
The purity of ligands and complexes were checked from mass
spectra at 70 ev by using AEIMS 30 mass spectrometer with
heating rate 40◦C/min and mass range (50–1000).
Cu(II), Co(II), and Mn(II) Complexes of (2ABPH)
Selected transition metal chloride salts like (CoCl2.6H2O,
MnCl2.4H2O and CuCl2.H2O (Fluka)) and all the used solvents
were of pure or spectroscopic grade.
These complexes were synthesized by dissolving the ap-
propriate amount of 2ABPH ligand (1 mmole, in 25ml 99%
methanol) with stirring and heating on a hot-plate at 60–70◦C
till completely soluble. Then added the metal ions as solid
(0.5 mmole) and continued stirring with heating till all metallic-
salts are dissolved. The volume of the obtained solutions was
reduced to one-half by evaporation followed by adding 20 ml
acetone with stirring and heating carefully till obtaining the
colored solid complexes of 2ABPH. The Cu(II), Co(II), and
Magnetic measurements were carried out on a Sherwood
Scientific magnetic balance using Gouy method.
Two very good solid calibrants are used: Hg[Co(CNS)4] and
[Ni(en)3](S2O3). They are easily prepared pure, do not decom-
pose or absorb moisture, and pack well. Their susceptibilities at
20◦C are 16.44 × 10−6 and 11.03 × 10−6 c.g.s. units, decreas-
ing by 0.05×10−6 and 0.04×10−6 per degree temperature raise,
respectively, near room temperature. The cobalt compound, be-
sides having the higher susceptibility, also packs rather densely
and is suitable for calibrating low fields, while the nickel com-
pound with lower susceptibility and density is suitable for higher
field.[32] Here we were used Hg[Co(CNS)4] only as calibrant.
Molar conductivities of freshly prepared 1.0×10−3
mol/dm−3 DMSO solutions were measured using Jenway 4010
conductivity meter.
H2N
CH
N
HN
Thermogravimetric analysis (TGA and DTG) were carried
out in dynamic nitrogen atmosphere (30 ml/min) with a heating
rate of 10◦C/min using a Schimadzu TGA-50H thermal ana-
lyzer.
Optical Absorption
The absorption spectra were recorded using a perkin-Elmer
Lambda 4B spectrophotometer in the range 200–900 nm.
FIG. 1. Structure of synthesized 2-aminobenzaldehyde phenylhydrazone
(2ABPH).

Cu(II), Co(II), AND Mn(II) COMPLEXES
297
FIG. 2. Spectral emission curves of Xenon arc lamp.
Mass Spectra
Dye Photostability
The most significant m/z peaks in the Figure 3 of mass
spectrum of 2ABPH free ligand were detected and assigned.
The 2-aminobenzaldehyde phenylhydrazone (2ABPH) shows
one peak at m/z 211 assigned to the C13H13N3 molecular
ion. It also shows a series of peaks, i.e., m/z(%); 195(0.5),
167(3), 105(32), 77(100), and 65(54) corresponding to various
fragments; [C13H11N2]+, [C12H9N]+, [C7H7N]+, [C6H5]+ and
[C5H5]+, respectively. Their signals give an idea about the con-
struction of ligand.
Solar simulator Xenon arc lamp "250 w" was used. The
spectrum of lamp is shown in Figure 2, which had the same
spectrum as the sun. The degradation of samples was studied by
analyzing the UV-vis. absorption spectra. The dye photostability
was calculated by dividing the absorbance after exposure to
light by that before exposure. The photostability as a function
of exposure time has been given.
RESULTS AND DISCUSSION
The results of the elemental analysis and physical data of the
2-aminobenzaldehyde phenylhydrazone (2ABPH) Schiff base
and their Mn(II), Co(II), and Cu(II) complexes exist in Table 1.
The complexes are air-stable, with melting points different from
Molar Conductivities of Metal Chelates
The molar conductivity (ꢀm) values for the 2ABPH com-
the free 2ABPH, insoluble in H2O, and most of organic solvents plexes in DMSO solvent (1.0 × 10−3 M) at 30◦C were in the
(like alcohols, benzene, acetonitrile) on cold except for DMSO range of (75–81) ꢁ−1 cm−1M−1 (Table 1), prove that the pres-
and DMF are very soluble.
ence of coordinated counter ions, since the 2ABPH complexes
TABLE 1
Elemental analyses and physical data of 2-aminobenzaldehyde phenylhydrazone (2ABPH) and their Mn(II), Co(II), and Cu(II)
complexes
Content ((calculate) found)
ꢀ
Complexes
Mwt.
% C
% H
% N
%M
—
(S cm2 mol−1
)
2ABPH C13H13N3
211.27 (73.84) 73.77 (6.15) 6.13 (19.88) 19.60
35
77
81
75
[Mn(2ABPH)2(Cl)2].4H2O (C26H34N6Cl2Mn) 620.48 (50.28) 49.98 (5.48) 5.35 (13.54) 13.48 (8.85) 8.78
[Co(2ABPH)2(Cl)2].6H2O C26H38N6Cl2Co) 660.47 (47.24) 47.19 (5.75) 5.66 (12.72) 12.56 (8.92) 8.87
[Cu(2ABPH)2(Cl)2].H2O C26H28N6Cl2Cu)
575.09 (54.25) 54.19 (4.87) 4.83 (14.61) 14.45 (11.05) 10.92

298
M. S. REFAT ET AL.
FIG. 3. Mass spectrum of 2-aminobenzaldehyde phenylhydrazone (2ABPH) ligand.
have a molar ratio (1: 2, M: ligand), and suggesting them to the complexation process between two moieties of ligand and
be slightly-electrolytes nature.[31,33−35] Conductivity measure- mononuclear metal(II) chlorides. In the ligand there are three
ments are in a good agreement with the elemental analysis data, strong intensity bands at 1600, 1572, and 1535 cm−1 attributable
where Cl− ions are detected by addition of AgNO3 solution, in- to ν(C = N), δ(NH2) and δ(NH), respectively.[36] On complexa-
side the coordination sphere of the complexes by the dissolving tion, the bands corresponding to δ(NH2) and δ(NH) are shifted
of the all complexes using nitric acid.
towards lower side (ca. 40–50), which suggest that the ligand
acts as bidentate chelating agent coordinating through the lone
pair of electron for both nitrogen atoms of -NH2 and azomethine
groups, which is further supported by appearance of a medium
intensity band in the region 440–510 cm−1 assignable to ν(M-
N) vibration. Bands appearing at 1490, 1442, 1129, 1069, 821,
784, and 745 cm−1are the usual modes of phenyl ring vibrations.
The previous bands corresponding to phenyl ring reveal small
shifts in the resulted complexes than free ligand; this is usual
due to the expected symmetry and electronic structure changes
upon complexation.
Infrared Spectra
The IR spectra in the (4000–400 cm−1) region provide infor-
mation regarding the coordination mode in the complexes and
were analyzed by comparison with data for ligand (2ABPH).
The most relevant bands and proposed assignments for all com-
plexes along with the ligand are given in Table 2, and the spectra
of ligand and their complexes are shown in Figure 4. The IR
spectrum of ligand shows bands at 3424 and 3293 cm−1, which
may be assigned to the –NH2and –NH groups, respectively. In
the IR spectra of ligand as well as the complexes, the shifted
of band in the region ∼3400 cm−1 corresponding to free pri-
mary amine and the blue shift of –CH = N- group towards
Electronic Spectra and Magnetic Measurements
The diffuse reflectance spectrum of the manganese(II) com-
lower side suggests that the two nitrogen atoms are involved in plex shows three bands at 17,482, 22,222, and 27,397 assignable

Cu(II), Co(II), AND Mn(II) COMPLEXES
299
NH
2
CH
N
HN
CH
N
-C5H2
-CH2N
-NH2
NH
NH
m/z(%); 167(3)
m/z(%); 195(0.5)
m/z(%); 211(10)
HN
CH
3
-C
-CH2N
m/z(%); 65(54)
m/z(%); 77(100)
m/z(%); 105(32)
SCH. 1. Fragment patterns of 2-aminobenzaldehyde phenylhydrazone (2ABPH).
4
6
4
6
4
6
is not deprotonated, but the lone pair of electrons on nitro-
gen atoms for both –CH = N- and NH2-Ph participated in the
complexation.
to the T1g → A1g, T2g(G)→ A1g and T1g(D)→ A1g, tran-
sitions, respectively.[37] The magnetic moment value is 5.57
B.M., which proves the presence of Mn(II)/2ABPH com-
plex in octahedral geometry. The electronic spectrum of the
cobalt(II)/2ABPH complex have three transition bands lo-
cated at 15,873, 19,230, and 23,923. These bands are as-
Thermal Analysis
Thermograms (TG/DTG) of the 2ABPH and their Mn(II),
Co(II) and Cu(II) transition metal complexes are discussed
and assigned in Table 3 and referred to in Figure 5 as
follows.
4
4
4
4
signed to the ν1 = T1g(F)→ T2g(F), ν2 = T1g(F)→ A2g(F)
4
4
and ν3 = T1g(F)→ T2g(P), respectively. These transitions cor-
respond to the octahedral geometrical structure.[37] The mag-
netic susceptibility measurements at the room temperature were
carried out according to Gauy method and lie at 4.45 B.M., in-
dicating the presence of three unpaired electrons.[38] Magnetic
moment value of copper(II) complex suggests that the Cu(II)
complex has octahedral structure with planar arrangement of
two ligands molecule around Cu(II)/2ABPH complex and the
chloride ions occupying axial position.
The 2ABPH ligand melts at about 227oC with simultaneous
decomposition. The decomposition steps seem to be consistent
with a mass loss of (obs. = 98.40%, calc. = 100%) due to
evolution of 13/2C2H2+ 3/2N2 gaseous molecules. The differ-
ence between the calculated and observed data devoted to the
residual carbon. From the corresponding DTG curve, only one
endothermic peak is noted.
The spectra of free ligand 2ABPH and its Mn(II), Co(II),
and Cu(II) complexes in DMSO were discussed. There are five
essential peaks at around 220 and 500 nm, which are assigned
to (220, 245, and 290 nm) π − π* and (340 and 400 nm) n-
π* intraligand transitions, respectively. The three bands 220,
245, and 290 nm are probably due to a π − π* of the aromatic
rings, but the other two bands 340 and 400 nm are assigned to
the azomethine and amino groups.[39−42] After complexation,
the absorption bands located at the same place of free ligand,
but with hyperchromically affected. This mean that the ligand
The thermal decomposition of Mn(II)/2ABPH complex oc-
curs within three steps. The first degradation step occurs in the
range of 30–250◦C, and it is corresponds to the eliminated of
3H2O molecules with a weight loss of (obs. = 8.86%, calc. =
8.70%). The second and third steps fall in the range of 250–
800◦C, which are assigned to loss of 2HCl + 2C13H13N3 with
a weight loss (obs = 79.11%, calc = 79.86%). The MnO is the
final product remains stable till 800◦C.
The thermal decomposition of cobalt(II)/2ABPH complex
occurs via four steps. The first step ranged at 30–130◦C

300
M. S. REFAT ET AL.
FIG. 4. Infrared spectra of: (A) 2ABPH, (B) Mn+2/2ABPH, (C) Co+2/2ABPH, and (D) Cu+2/2ABPH.

Cu(II), Co(II), AND Mn(II) COMPLEXES
301
FIG. 4. (Continued)

302
M. S. REFAT ET AL.
TABLE 2
IR spectral data of the 2ABPH ligand and its complexes
Compounds
2ABPH
ν(NH2)
ν(NH)
ν(C = N)
1600
δ(NH2)
δ(NH)
ν(M-N)
Phenyl ring
3424
3293
1572
1535
—
1490
1442
1129
1069
821
784
745
Mn(II)
Co(II)
3419
3405
3295
3297
1595
1595
1530
1527
1489
1491
507 443
1348
1143
1068
808
750
508
446
1347
1143
1097
1069
808
750
Cu(II)
3410
3299
1596
1524
1498
505
1347
1140
1096
1071
808
737
corresponding to the loss of 2H2O molecules representing a The CoO and the residual carbon atoms are the final products
weight loss of (obs. = 5.12%, calc. = 5.45%). The second step remain stable till 800◦C.
occurring at 130–200◦C assignable to the loss of 2H2O with
The thermal degradation of the Cu(II)/2ABPH complex oc-
a weight loss of (obs. = 6.24%, calc. = 5.45%). The third curs in mainly three degradation stages, reveals a mass loss in
and fourth steps take place within the temperature range (200– the temperature range 30–800◦C corresponding to the forma-
800◦C) with the weight loss of (obs. = 69.23%, calc. = 68.58%) tion of CuO. The three endothermic peaks were observed in
TABLE 3
Kinetic parameters using the Coats–Redfern (CR) and Horowitz–Metzger (HM) operated for 2-aminobenzaldehyde
phenylhydrazone (2ABPH) and their Mn(II), Co(II), and Cu(II) complexes
Parameter
Complex Stage Method E (kJ mol−1
)
A (s−1
)
ꢂS (J mol−1 K−1
)
ꢂH (kJ mol−1
)
ꢂG (kJ mol−1
)
R
2ABPH
Mn(II)
Co(II)
Cu(II)
1st
1st
1st
1st
CR
HM
CR
HM
CR
HM
CR
1.20 × 105
1.19 × 105
1.87 × 105
1.80 × 105
1.31 × 105
1.34 × 105
1.02 × 104
1.00 × 105
5.12 × 1010
5.58 × 1010
1.39 × 1022
1.54 × 1023
3.65 × 1020
3.22 × 1020
4.76 × 1011
5.66 × 1012
−1.53 × 101
−1.38 × 101
−1.78 × 101
−2.12 × 101
−7.45 × 101
−8.81 × 101
−7.63 × 101
−7.84 × 101
1.22 × 105
1.02 × 105
1.62 × 105
1.08 × 105
1.34 × 105
1.42 × 105
1.96 × 105
2.81 × 105
1.42 × 104
1.48 × 104
2.00 × 104
2.07 × 104
7.65 × 104
7.86 × 104
8.46 × 104
8.66 × 104
0.9939
0.9998
0.9890
0.9966
0.9988
0.9999
0.9958
0.9939
HM

Cu(II), Co(II), AND Mn(II) COMPLEXES
303
B
A
100
80
60
40
20
0
100
80
60
40
20
0
-20
0
200
400
600
800
0
200
400
600
800
o
o
Temp C
Temp C
D
C
100
80
60
40
20
0
100
80
60
40
20
0
0
200
400
600
800
0
200
400
600
800
o
o
Temp C
Temp C
FIG. 5. TGA curves of: (A) 2ABPH, (B) Mn+2/2ABPH, (C) Co+2/2ABPH, and (D) Cu+2/2ABPH compounds.
DTG curve (Figure 5). The maxima of these peaks are found
to be 245,430, and 550◦C, respectively. The mass loss at the
first stage in the temperature range 30–250◦C corresponds to
the melting point of the 2ABPH ligand because no weight loss
was detected in the TG curve. The second and third peaks at
430 and 550◦C DTGmax, respectively, correspond to decompo-
sition of the ligand and corresponding to the loss of 2ABPH
and 2HCl moieties and the final thermal product obtained at
800◦C is CuO. The overall weight loss (obs. = 87.46%, calc.
= 86.17%) agrees well with the proposed structure. Based on
the essential DTGmax temperatures of the decomposition of 2-
aminobenzaldehyde phenylhydrazone complexes, the thermal
stabilities of the complexes depend on the central metal ions,
the sequence follows: Co2+ (699 ◦C) > Mn2+ (650◦C) > Cu2+
(550◦C).
Kinetic Studies
Most commonly used methods in determining the rate-
dependent parameters of solid-state non-isothermal decompo-
sition reactions by analysis of TG curves are the differential
method of Freeman and Carroll,[43] integral method of Coat and
Redfern,[44] and the approximation method of Horowitz and
Metzger.[45]
Herein, the general thermal behaviors of the 2ABPH com-
plexes in terms of stability ranges, peak temperatures and values
of kinetic parameters, are discussed in Table 4 and Figure 6. The
kinetic parameters have been evaluated using the Coats-Redfern
equation:
ꢀ
ꢀ
α
n
T2
dα
A
E∗
=
exp(−
T1
)dt
[1]
(1 − α)
ϕ
RT
0

304
M. S. REFAT ET AL.
-13.0
-13.1
-13.2
-13.3
-13.4
-13.5
HM
CR
-0.60
-0.66
-0.72
-0.78
-0.84
-0.90
(A)
6.0
(A)
-13.6
-6.0 -4.5 -3.0 -1.5 0.0
1.5
3.0
4.5
1.926 1.932 1.938 1.944 1.950 1.956 1.962 1.968
θ(k)
1000/T(K)
-12.2
-12.4
-12.6
-12.8
-13.0
-13.2
-13.4
-13.6
-0.5
HM
CR
-0.6
-0.7
-0.8
-0.9
-1.0
-1.1
-1.2
(B)
(B)
2.65
-4
-2
0
2
4
6
2.64
2.66
2.67
1000/T(K)
2.68
2.69
2.70
2.71
θ(k)
-11.75
-12.00
-12.25
-12.50
-12.75
-13.00
-13.25
-13.50
-0.45
-0.60
-0.75
-0.90
-1.05
-1.20
-1.35
CR
HM
(C)
4.5
(C)
3.100
3.125
3.150
3.175
3.200
-6.0 -4.5 -3.0 -1.5 0.0
1.5
3.0
6.0
1000/T(K)
θ(k)
FIG. 6. Kinetic data of: (A) 2ABPH, (B) Mn+2/2ABPH, (C) Co+2/2ABPH, and (D) Cu+2/2ABPH compounds.

Cu(II), Co(II), AND Mn(II) COMPLEXES
305
-0.2
-0.3
-0.4
-0.5
-0.6
-0.7
-0.8
-0.9
-11.50
-11.75
-12.00
-12.25
-12.50
CR
HM
(D)
(D)
-12.75
2.825
2.850
2.875
2.900
2.925
-5.0
-2.5
0.0
θ(k)
2.5
5.0
7.5
1000/T(K)
FIG. 6. (Continued)
This equation on integration gives
The Horowitz-Metzger equation is an illustrative of the ap-
proximation methods.
ꢁ
ꢂ
ꢁ
ꢂ
ln(1 − α)
E∗
AR
ϕE∗
ln
−
= −
+ ln
.
[2]
log[{1 − (1 − α)1−n}]/(1 − n)] = E∗θ/2.303RT 2s for n = 1
[4]
T 2
RT
A plot of left-hand side (LHS) against 1/T was drawn. E∗ is
the energy of activation in J mol−1 and calculated from the slop
and A in (s−1) from the intercept value. The entropy of activation
ꢂS∗ in (JK−1mol−1) was calculated by using the equation:
When n = 1, the LHS of equation 4 would be log[− log(1−α)].
For a first-order kinetic process the Horowitz-Metzger equation
may be written in the form:
log[log(wα/wγ )] = E∗θ/2.303RT s2 − log 2.303,
ꢂS∗ = Rln(Ah/kBTs),
[3]
where θ = T − Ts, wγ = wα − w, wα = mass loss at the
where kB is the Boltzmann constant, h is the Plank’s constant completion of the reaction; w = mass loss up to time t. The
and Ts is the DTG peak temperature.[46]
plot of log[log(wα/wγ )] vs θ was drawn and found to be linear
TABLE 4
Thermal data of 2-aminobenzaldehyde phenylhydrazone (2ABPH) and their Mn(II), Co(II), and Cu(II) complexes
TGA weight loss (%)
Compounds
Steps
Temp. range (◦C) DTG peak (◦C) Calc.
Found
Assignments
2ABPH
Mn(II)
1st
1st
30–800
30–250
227
205
100
8.70
98.40
8.86
13/2C2H2 + 3/2N2 + residual carbon
3H2O
2nd , 3rd
250–800
425, 650
79.86
79.11
2C13H13N2 + 2HCl
MnO
Co(II)
Cu(II)
1st
2nd
3rd, 4th
30–130
130–200
200–800
93
145
435, 699
5.45
5.45
68.58
5.12
6.24
69.23
2H2O
2H2O
C21H26N6
CoO + residual carbon
Melting point
2C13H13N2 + 2HCl
CuO
1st
2nd
3rd
30-800
245
430, 550
—
86.17
—
87.46

306
M. S. REFAT ET AL.
TABLE 5
Rate constants (k) of photodegradation and half life times of doped 2ABPH and their metal complexes in PMMA
Sample
K (min−1
)
t1 (min)
/
2
2ABPH/PMMA
372 nm
4.807 × 10−4
364.3 nm
275.8 nm
3.664 × 10−5
274.6 nm
372 nm
275.8 nm
18915
274.6 nm
20643
1441.65
364.3 nm
2062
2ABPH/Mn2+ complex /PMMA
3.37 × 10−4
3.357 × 10−5
from the slope of which E∗ was calculated. The pre-exponential
Structure of the 2ABPH Complexes
factor, A, was calculated from the following equation:
It can be concluded from the above discussions on the
2ABPH ligand and its Mn(II), Co(II), and Cu(II) complexes us-
ing the elemental analysis, molar conductivity, IR, UV, 1HNMR,
and mass spectra, as well as TG/DTG, that the mode of coordi-
nation occurs through both of nitrogen atoms one of them for
amino ( NH2) group and the other of lone pair of electron of
nitrogen atom specialized to azomethine group (Figure 7).
E∗/RT 2s = A/[ϕ exp −E∗/RT s].
The entropy of activation, ꢂS∗, was calculated from equation
3. The enthalpy activation, ꢂH∗, and Gibbs free energy, ꢂG∗,
were calculated from; ꢂH∗ = E∗ – RT and ꢂG∗ = ꢂH∗–
TꢂS∗, respectively.
Photostabilities of 2ABPH and their Metal Complexes
In case of 2ABPH undoped, highly delocalized bondes (C=C
and C=N) are mainly affected by UV-Vis radiation (photodegra-
dation origin). Also, the photochemical degradation of 2ABPH
doped in PMMA occurs only in the presence of suitable optical
radiation, which produces large local increases in temperature
and thermal destruction of the dye molecules.[48] At the Xenon
arc lamp powers which are used, there is no general consensus
concerning the mechanism responsible for thermal damage of
polymeric materials. It can be seen that dye molecules embed-
ded in the PMMA matrix do not undergo any change in chemical
properties at low powers.[48] 2ABPH doped in PMMA were ex-
posed indoors to UV-Vis radiation and the change in the absorp-
tion spectra was achieved at different times during irradiation
ꢂG is positive for reaction for which ꢂH is positive and
ꢂS is negative. The reaction for which ꢂG is positive and
ꢂS is negative considered as unfavorable or non spontaneous
reactions.
The thermodynamic data obtained with the two methods
are in harmony with each other. The activation energy of
Mn+2/2ABPH complex is expected to increase in relation with
decrease in their radii.[47] The smaller size of the ions permits
a closer approach of the ligand. Hence, the E value for the
Mn+2 complex is higher than that for the other Co+2 and Cu+2
complexes.
The correlation coefficients of the Arrhenius plots of the
thermal decomposition steps were found to lie in the range 0.98
to 0.99, showing a good fit with linear function. It is clear that
the thermal decomposition process of all 2ABPH complexes is
non-spontaneous, i.e., the complexes are thermally stable.
4
t= 8 h
t= 5 h
t= 8 h
3
H2N
2
1
0
CH
N
NH
Cl
HN
N
M
XH2O
Cl
CH
NH2
200
400
600
800
Wavelength (nm)
FIG. 8. Photostability of 2ABPH doped in PMMA before and after exposure
to UV-Vis light. (Figure is provided in color online.)
FIG. 7. The mode of chelation of the 2ABPH complexes, where M = Mn(II),
Co(II), and Cu(II); X = 1, 4 and 6.

Cu(II), Co(II), AND Mn(II) COMPLEXES
307
unusual tridentate coordination mode. J. Mol. Struct. 2007, 826(2-3), 75–
81.
4
3
2
1
0
0 h
5 h
8 h
7. Patel, R.N.; Singh, N.; Gundla, V.L.N. Synthesis, structure and properties
of ternary copper(II) complexes of ONO donor Schiff base, imidazole, 2,2ꢁ-
bipyridine and 1,10-phenanthroline. Polyhedron 2006, 25(17), 3312–3318.
8. Bortoluzzi, M.; Paolucci, G.; Pitteri, B.; Vavasori, A. Metal-assisted synthe-
ses and NMR characterization of square-planar Pd(II) and Pt(II) complexes
with tridentate nitrogen-donor chelate ligands. Inorg. Chem. Comm. 2006,
9(12), 1301–1303.
9. Banerjee, S.; Lassahn, Paul-G.; Janiak, C.; Ghosh, A. Supramolecular ar-
chitecture of cadmium(II)–terephthalate complexes having a tridentate or
tetradentate Schiff base as blocking coligand. Polyhedron 2005, 24(18),
2963–2671.
10. Das, S.; Pal, S. Copper(II) complexes with tridentate N-(benzoyl)-Nꢁ-
(salicylidine)-hydrazine and monodentate N-heterocycles: Investigations
of intermolecular interactions in the solid state. J. Mol. Struct. 2005, 753(1-
3), 68–79.
11. Marcos, M.; Barbera, J.; Ros, M. B.; Serrano, J. L. A contribution to the
study of the nematic-isotropic transition. influence of polar terminal groups.
Mol. Cryst. Liq. Cryst. 1988, 163, 139–155.
200
400
600
800
Wavelength(nm)
12. Marcos, M.; Romero, P.; Serrano, J.L.; Bueno, C.; Cabeza, J.A.; Oro, L.A.
Liquid crystal derivatives of transition metals (I): tetracoordinated copper
(II) complexes derived from Schiffs bases. Mol. Cryst. Liq. Cryst. 1989,
167, 123–134.
FIG. 9. Photostability of 2ABPH/Mn2+ complex doped in PMMA before and
after exposure to UV-Vis light. (Figure is provided in color online.)
13. Billman, J.H.; McDowell, J.W. The reductive acylation of Schiff bases using
trimethylamine borane. IV. J. Org. Chem. 1962, 27, 2640–2643.
14. Metzler, D.E.; Ikawa, M.; Snell, E.E. A general mechanism for vitamin
B6-catalyzed reactions1. J. Am. Chem. Soc. 1954, 76, 648–652.
15. Surati, K.R.; Thaker, B.T. Synthesis, spectral, crystallography and thermal
investigations of novel Schiff base complexes of manganese (III) derived
from heterocyclic β-diketone with aromatic and aliphatic diamine. Spec-
trochim. Acta Part A 2010, 75(1), 235–242.
period (230 min and 480 min, respectively) and shown in Figure
8. Also, 2ABPH/Mn2+ complex was prepared, doped in PMMA,
and shown after exposure to UV-Vis radiation an enhancement
of the photostability, as shown in Figure 9. The increase in pho-
tostability refers to strong chelation (complexation of dye with
metal).
The rate constant of photo-degradation of dyes was estimated
16. Sridhar, S. K.; Saravanan, M.; Ramesh, A. Synthesis and antibacterial
screening of hydrazones, Schiff and Mannich bases of isatin derivatives.
Eur. J. Med. Chem. 2001, 36, 615–625.
according to the following equation:[49]
2.303
A0
A
17. Panneerselvam, P.; Nair, R.R.; Vijayalakshmi, G.; Subramanian, E.H.; Srid-
har, S.K. Synthesis of Schiff bases of 4-(4-aminophenyl)-morpholine as
potential antimicrobial agents. Eur. J. Med. Chem. 2005, 40, 225–229.
18. Pandeya, S.N.; Sriram, D.; Nath, G.; DeClercq, E. Synthesis, antibacterial,
antifungal and anti-HIV activities of Schiff and Mannich bases derived
from isatin derivatives and N-[4-(4ꢁ-chlorophenyl)thiazol-2-yl] thiosemi-
carbazide. Eur. J. Pharm. Sci. 1999, 9, 25–31.
19. Timmons J. C.; Hubin T.J. Preparations and applications of synthetic linked
azamacrocycle ligands and complexes. Coord. Chem. Rev. 2010, 254(15-
16), 1661–1685.
k =
log
[5]
t
Where, A0 & A the absorption before and after irradiation for
time (t). The k value and half life times are listed in Table 5. It is
clear from the degradation data that the complexation modifies
the photostability of dye.[50]
20. Mirkhani, V.; Kia, R.; Vartooni, A.R.; Fun, H.-K. New Re(I)
tricarbonyl-diimine complexes with N,Nꢁ-bis(substituted benzaldehyde)-
1,2-diiminoethane Schiff base ligands: Synthesis, spectroscopic and elec-
trochemical studies and crystal structures. Polyhedron 2010, 29(6), 1600–
1606.
REFERENCES
1. Knopfer, G. Gegenseitige umsetzung von semicarbazonen und phenylhy-
drazonen. Monatsh. Chem. 1910, 31(2), 87–110.
2. Pfeiffer, H. Indirect nitrin test for coli bacilli in the urine. Munch. Med.
Wochenschr. 1950, 92(31-32), 1315–1316.
21. Jia, L.; Jiang, P.; Xu, J.; Hao, Z.-Y.; Xu, X.-M.; Chen, L.-H.; Wu, J.-C.; Tang,
N.; Wang, Q.; Vittal, J.J. Synthesis, crystal structures, DNA-binding proper-
ties, cytotoxic and antioxidation activities of several new ternary copper(II)
complexes of N, Nꢁ-(p-xylylene)di-alanine acid and 1,10-phenanthroline.
Inorg. Chim. Acta 2010, 363(5), 855–865.
22. Parker, D.; Dickins, R.S.; Purschmann, H.; Crossland, C.; Howard, J.A.K.
Being excited by lanthanide coordination complexes:aqua species, chirality,
excited-state chemistry, and exchange dynamics. Chem. Rev. 2002, 102,
1977–2010.
23. Parker, D. Excitement in f block: structure, dynamics and function of nine-
coordinate chiral lanthanide complexes in aqueous media. Chem. Soc. Rev.
2004, 33, 156–165.
24. Williams, L.A.D.; Howell, R.C.; Young, R.; Kahwa, I.A. Neuropharma-
cological actions of some binuclear lanthanide(III) complexes. Comp.
3. Selvakumar, P.M.; Suresh, E.; Subramanian, P.S. Synthesis, spectral charac-
terization and structural investigation on some 4-aminoantipyrine contain-
ing Schiff base Cu(II) complexes and their molecular association. Polyhe-
dron 2007, 26(4), 749–756.
4. Boghaei, D.M.; Farvid, S.S.; Gharagozlou, M. Interaction of cop-
per(II) complex of compartmental Schiff base ligand N,Nꢁ-bis(3-
hydroxysalicylidene)ethylenediamine with bovine serum albumin. Spec-
trochim. Acta A 2007, 66(3), 650–655.
5. Khanmohammadi, H.; Amani, S.; Lang, H.; Ru¨effer, T. Synthesis and char-
acterization of Mg(II), Mn(II), Zn(II) and Cd(II) complexes with a new
heptaaza Schiff base pendant-armed macrocycle: X-ray crystal structure,
NMR and computational study. Inorg. Chim. Acta 2007, 360(2), 579–587.
6. Karmakar, R.; Choudhury, C.R.; Batten, S.R.; Mitra, S. Two new copper(II)
complexes with the shortest (N–N) diazine based rigid ligand: Example of

308
M. S. REFAT ET AL.
Biochem. Physiol. Part C: Toxicol. Pharmacol. 2001, 128, 119– 37. Lever, A.B.P. Inorganic Electronic Spectroscopy, 1st Ed.; Elsevier: Ams-
125.
terdam, 1968.
25. Woods, M.; Kovacs, Z.; Sherry, A.D. Targeted complexes of lanthanide(III)
ions as therapeutic and diagnostic pharmaceuticals. J. Supramolecular
Chem. 2002, 2, 1–15.
38. Earnshaw, A. Introduction to Magneto Chemistry; Academic press Inc.:
1968.
39. Fasman, G.D. Handbook of Biochemistry and Molecular Biology; Nucleic
Acids, I, 65–215, CRC Press, 1968.
26. Refat, M.S.; El-Deen, I. M.; Ibrahim, H.K.; El-Ghool, S. Synthesis and
spectroscopic studies of some transition metal complexes of a novel Schiff 40. Kasumov, V.T.; Ozalp-Yaman, S.; Tas, E. Synthesis, spectroscopy and elec-
base ligands derived from 5-phenylazo-salicyladehyde and o-amino benzoic
acid. Spectrochim. Acta Part A 2006, 65(5), 1208–1220.
27. Refat, M.S.; Ibrahim, A.A. Synthesis, infrared spectra and thermal studies
trochemical behaviors of nickel(II) complexes with tetradentate Shiff bases
derived from 3,5-But2-salicylaldehyde. Spectrochimica Acta A 2005, 62,
716–720.
of Zn(II), Cd(II) and Hg(II) complexes with 2-aminobenzaldehyde phenyl- 41. Zollezi, S.; Decinti, A.; Spodine, E. Syntheses and characterization of cop-
hydrazone “nitrin” ligand. Spectrochim. Acta Part A 2008, 70(1), 234–242.
28. Refat, M.S.; El-Korashy, S.A.; Kumar, Deo N.; Ahmed, A.S. Syntheses
and characterization of Ru(III) with chelating containing ONNO donor
quadridentate Schiff bases. Spectrochimica Acta A 2008, 70(4), 898–906.
29. Refat, M.S.; Chandra, S.; Tyagi, M. Spectroscopic, thermal and biocidal
studies on Mn(II), Co(II), Ni(II) and Cu(II) complexes of tridentate ligand
per(II) complexes with Schiff-base ligands derived from ethylenediamine,
diphenylethylenediamine and nitro, bromo and methoxy salicylaldehyde.
Polyhedron 1999, 18, 897–904.
42. Tuncel, M.; Serin, S. Synthesis and characterization of Copper(II),
Nickel(II) and Cobalt(II) complexes with Azo-linked Schiff base ligands.
Synth. React. Inorg. Met.-Org. Nano Met. Chem. 2005, 35, 203–212.
having semicarbazone moieties. J. Therm. Anal. Cal. 2010, 100(1), 261– 43. Freeman, E.S.; Carroll, B. The application of thermoanalytical techniques
267.
to reaction kinetics: the thermogravimetric evaluation of the kinetics of the
decomposition of calcium oxalate monohydrate. J. Phys. Chem. 1958, 62,
394–397.
30. Refat, M.S.; El-Deen, I.M. Grabchev, I.; Anwer, Z.M.; El-Ghol, S. Spec-
trochim. Acta A. 2009, 72(4), 772.
31. Refat, M.S.; El-Deen, I.M.; Anwer, Z.M.; El-Ghol, S. Bivalent transition 44. Coats, A.W.; Redfern, J.P. Kinetic parameters from thermogravimetric data.
metal complexes of coumarin-3-yl thiosemicarbazone derivatives: Spec- Nature 1964, 201, 68–9.
troscopic, antibacterial activity and thermogravimetric studies. J. Mol. Str. 45. Horowitz, H.W.; Metzger, G. A new analysis of thermogravimetric traces.
2009, 920, 149–162. Anal. Chem. 1963, 35, 1464–8.
32. Burger, K. Coordination Chemistry: Experimental Methods; Butterworth 46. Flynn, J.H.; Wall, L.A. A quick, direct method for the determination of
group: Britain, 1973.
activation energy from thermogravimetric data. Polym. Lett. 1966, 4, 323–
33. Geary, W.J. The use of conductivity measurements in organic solvents for
8.
the characterisation of coordination compounds. Coord. Chem. Rev. 1971, 47. Tunali, N.K.; Ozkar, S. Inorganic Chemistry; Gazi University Publication,
7, 81–122.
Pub. No. 185, AnKara, 1993.
34. Abd El-Wahed, M.G.; Refat, M.S.; El-Megharbel, S.M. Spectroscopic stud-
ies on the complexation of some transition metals with Chloramphenicol
drug. J. Mol. Str. 2008, 892(1-3), 402–413.
48. Kim, O.; Lee, K.; Huang, Z.; Heuer, W.; Paik-Sung, C. Oligothiophene as
photonic/electronic property modulator. Optical Materials 2003, 21, 559–
564.
35. Refat, M.S.; El-Deen, I.M.; Anwer, Z.M.; El-Ghol, S. Spectroscopic studies
and biological evaluation of some transition metal complexes of Schiff-base
ligands derived from 5-arylazo-salicylaldehyde and thiosemicarbazide. J.
Coord. Chem. 2009, 62(10), 1709–1718.
36. Nakamoto, K. Infrared Spectra of Inorganic and Coordination Compounds;
Wiley Interscience: NY, 1970.
49. Grabchev, I.; Bojinov, V. Synthesis and characterisation of fluorescent poly-
acrylonitrile copolymers with 1,8-naphthalimide side chains. Polym. De-
grad. Stab. 2000, 70(2), 147–153.
50. Esumi, K.; Hayakawa, K.; Yoshimura, T. Morphological change of gold–
dendrimer nanocomposites by laser irradiation. J. Colloid and Interface
Science 2003, 268(2), 501–6.