Synthesis, spectroscopic characterization and biological activity of the metal complexes of the Schiff base derived from phenylaminoacetohydrazide and dibenzoylmethane

Article abstract of DOI:10.1016/j.saa.2007.11.011

A new series of mono and binuclear Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), La(III), Ru(III), Hf(IV), ZrO(II) and UO₂(II) complexes of phenylaminodibenzoylhydrazone have been synthesized and characterized by elementals analyses, IR UV-vis spectra, magnetic moments, conductances, thermal analyses (DTA and TGA) and electron spin resonance (ESR) measurements. The IR spectral data show that, the ligand behaves as a neutral bidentate type (15 and 16), monobasic bidentate type (6), or monobasic tridentate type (5, 7, 8, 10, 11, 13, 14, 17-21) or dibasic tridentate type 2-4, 9 and 12 towards the metal ion. Molar conductances in DMF solution indicate that, the complexes are non-electrolytes. The ESR spectra of solid complexes (9 and 10) show axial and non-axial types indicating a d_{(x2 - y2)} ground state with significant covalent bond character. However, complexes (11 and 12), show isotropic type, indicating manganese(II) octahedral geometry. Antibacterial and antifungal tests of the ligand and its metal complexes are also carried out and it has been observed that the complexes are more potent bactericides and fungicides than the ligand.

Full text of DOI:10.1016/j.saa.2007.11.011

Available online at www.sciencedirect.com
Spectrochimica Acta Part A 71 (2008) 90–99
Synthesis, spectroscopic characterization and biological activity
of the metal complexes of the Schiff base derived from
phenylaminoacetohydrazide and dibenzoylmethane
Abdou Saad El-Tabla,∗, Fathey A. El-Saieda,
Winfried Plassb, Ahmed Noman Al-Hakimia
a Department of Chemistry, Faculty of Science, Menoufia University, Gamal Street, Shebin El-Kom 00248, Egypt
b Department of Chemistry, Fridrich Schiller Universita¨t, Jena, Germany
Received 21 September 2007; received in revised form 14 November 2007; accepted 15 November 2007
Abstract
A new series of mono and binuclear Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), La(III), Ru(III), Hf(IV), ZrO(II) and UO2(II) complexes
of phenylaminodibenzoylhydrazone have been synthesized and characterized by elementals analyses, IR UV–vis spectra, magnetic moments,
conductances, thermal analyses (DTA and TGA) and electron spin resonance (ESR) measurements. The IR spectral data show that, the ligand
behaves as a neutral bidentate type (15 and 16), monobasic bidentate type (6), or monobasic tridentate type (5, 7, 8, 10, 11, 13, 14, 17–21) or dibasic
tridentate type 2–4, 9 and 12 towards the metal ion. Molar conductances in DMF solution indicate that, the complexes are non-electrolytes. The
ESR spectra of solid complexes (9 and 10) show axial and non-axial types indicating a d(x −y ) ground state with significant covalent bond character.
2
2
However, complexes (11 and 12), show isotropic type, indicating manganese(II) octahedral geometry. Antibacterial and antifungal tests of the ligand
and its metal complexes are also carried out and it has been observed that the complexes are more potent bactericides and fungicides than the ligand.
© 2007 Elsevier B.V. All rights reserved.
Keywords: Complexes; Spectroscopic studies; Conductivity; Thermal analyses; Syntheses; Magnetism; Biological activity
1. Introduction
[11,12]. These compounds showed antifungal and antibacterial
activities [11–13]. Metal(II) complexes of 2-acetypyridine ben-
zoylhydrazone ligand were synthesized and crystallographically
characterized [14]. Extensive investigations of this kind of com-
plexeshavebeenundertakenrecently, however, wehavereported
the synthesis and characterterization of metal complexes of
phenylaminodibenzoylhydrazone tridentate ligand.
Hydrazones and their coordination compounds are well
known to be biologically important and interest for their antibac-
terial, antitumour and antitubercular activities [1]. Also, it has
been used as analytical reagent [2], polymer-coating, ink, pig-
ment [3] and fluorescent materials [4]. Metal complexes of
a bishydrazone derived from isatin monohydrazone and 2-
hydroxy-1-naphthaldhyde have been reported and they possess
interesting biological properties [5,6]. Transition metal com-
plexes of salicyladehyde thiazolyl hydrazone were prepared and
characterized [7]. Number of copper(II) complexes of acylhy-
drazones had been extensively studied [8–10]. Copper(II) and
iron(III) complexes of phenylhydrazoacetylacetone isonicoti-
noyl hydrazone were synthesized and spectrally characterized
[2]. They were able to mimic bimetallic sites in various enzymes
2. Experimental
Reagent grade chemicals were used. Phenylaminoacetohy-
drazide was prepared by a published method [15]. Elemental
analyses were determined by the Analytical Unit of Cairo,
University of Egypt. Standard methods were used to deter-
mine the metal ion content. All metal complexes were dried
in vacuo over anhydrous CaCl2. The IR (as KBr pellets) spec-
tra were measured using a PerkinElmer 683 spectrophotometer
(4000–200 cm−1). Electronic spectra in DMF solutions were
recorded on a PerkinElmer 550 spectrophotometer. The con-
ductances of 10−3 M solution of the complexes in DMF were
∗
Corresponding author.
E-mail address: asaeltabl@yahoo.com (A.S. El-Tabl).
1386-1425/$ – see front matter © 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2007.11.011

A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
91
measured at 25 ◦C with a Bibby conductometer type MCl. The
1H NMR spectrum of the ligand in DMSO-d6 was recorded
using a 300 MHZ Varian NMR spectrometer. The thermal anal-
yses (DTA and TGA) were carried out in the air on a Shimadzu
DT-30 thermal analyzer from 27 to 800 ◦C at a heating rate of
10 ◦C/min. Magnetic moments were measured by Gouy method
using μeff = 2.84(XMT)1/2. All electron spin resonance (ESR)
measurements of solid complexes at room temperature were
made using a Varian E-109 spectrophotometer. DPPH was used
as a standard material.
bent loop rod. Disks were cut by sterilized cork borer and then
takenbysterilizedneedle. Theresultedpitsaresitesforthetested
compounds. The plates are incubated at 30 ◦C for 24–48 h and
then any clear zones present were detected.
3.2. Bacteria media
Nutrient agar medium was prepared by standard method [16].
E. coli was spread over each dish by using sterile bent loop rod.
Disks were cut by sterilized cork borer and then taken by steril-
ized needle. The resulted pits are sites for the tested compounds.
The plates are incubated at 37 ◦C for 24–48 h and then any clear
zones present were detected.
2.1. Preparation of the ligand (1) [H2L]
Phenylaminoacetohydrazide (1.7 g, 0.01 mol) was dissolved
in 25 mL of EtOH and dibenzoylmethane (2.3 g, 0.01 mol) in
15 mL EtOH was added dropwise. The reaction mixture was
refluxed with stirring for 3 h and, then cooled to room temper-
ature. The product was filtered off, washed several times with
EtOH and dried over anhydrous CaCl2.
4. Results and discussion
The reaction of phenylaminoacetohydrazide with dibenzoyl-
methane in EtOH 1:1, molar ratio, led to the formation of H2L,
as shown in Scheme 1.
The IR spectra of the H2L and its metal complexes show
that, the H2L has tautomeric forms (I–III) as shown below:
2.2. Preparation of metal complexes
(a) 2, 5, 8, 11, 17 and 21
These complexes were prepared by mixing stiochio-
metric ratios (1L:1M) of the ligand (30 mL EtOH)
and metal acetate (50 mL) EtOH. Ni(OAc)2·4H2O (2),
Co(OAc)2·4H2O (5), Cu(OAc)2·H2O (8), Mn(OAc)2·4H2O
(11), Zn(OAc)2·4H2O (17) and UO2(OAc)2 (21). The mix-
ture was refluxed on a hot plate with stirring for 1–2 h, and
then left it to cool to room temperature. Fine crystals which
separated were filtered off, washed several times with EtOH
and dried over anhydrous CaCl2.
(b) 3, 6, 9 and 18
These complexes were prepared by using the above
procedure, using Ni(NO3)2·6H2O (3), Co(NO3)2·6H2O
(6), Cu(NO3)2·3H2O (9) [few drops of TEA] and
Zn(NO3)2·XH2O (18). The mixture was refluxed on a hot
plate with stirring for 1–2 h. The precipitate which formed
was filtered off, washed several times with EtOH and dried
over anhydrous CaCl2.
(c) 4, 7, 10, 12–16, 19 and 20
These complexes were prepared by using the above
procedure, using NiCl2·6H2O (4), CoCl2·6H2O (7),
CuCl2.·XH2O (10), MnCl2·4H2O (12) [few drops of
TEA], FeCl3·6H2O (13), RuCl3 (14), ZrOCl2·8H2O (15),
HfCl4·8H2O (16), ZnCl2·4H2O (19) and LaCl3·7H2O (20).
The mixture was refluxed on a hot plate with stirring for
1–2 h and then left it to cool to room temperature. Fine crys-
tals which separated were filtered off, washed several times
with EtOH and dried over anhydrous CaCl2.
3. Microbiology
3.1. Fungus media
The reaction of the H2L with metal salts using (1:1) or
(2:1) molar ratios, led to the formation of metal complexes
with different geometries. All the compounds are intensely
Czapek Dox agar medium was prepared by standard method
[16]. Aspergillus niger was spread over each dish by using sterile

Table 1
Elemental analyses and physical properties of the H2L and its metal complexes
Comp no.
Molecular formula
Colour
Yield (%)
m.p. (◦C)
ꢀ
−1 mol−1 cm2
μeff (μB)
Found (Calc.) (%)
C
H
N
Cl
M
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
[(H2L)][C23H21N3O2]
[(HL)Ni(OAc)]·3H2O
[(L)Ni(H2O)]
Pink
85
79
80
76
78
77
80
81
77
82
75
79
76
77
82
80
79
81
84
75
80
70
170
118
280
105
110
300
245
190
160
115
110
225
–
2.3
2
1.3
2
–
74.1(74.4)
55.7(55.4)
61.8(61.9)
53.4(53.2)
55.4(55.4)
65.9(66.0)
51.7(51.5)
58.9(58.8)
43.3(43.3)
54.5(54.7)
55.9(55.7)
60.5(60.0)
53.1(53.6)
46.1(46.3)
40.7(40.9)
34.6(34.5)
51.3(51.3)
67.1(67.0)
54.5(54.5)
44.9(45.5)
40.5(40.9)
5.7(5.7)
5.5(5.4)
5.3(4.7)
5.2(5.2)
5.6(5.4)
5.3(5.4)
4.9(5.2)
4.7(4.9)
3.8(3.3)
4.5(4.8)
5.7(5.6)
5.6(5.0)
4.5(4.3)
5.1(4.9)
5.3(5.2)
4.1(4.1)
5.5(5.6)
5.1(5.1)
4.7(4.7)
3.8(4.0)
3.8(3.5)
11.0(11.3)
7.8(7.8)
9.0(9.4)
7.9(8.1)
7.9(7.8)
9.6(10.0)
7.6(7.8)
8.3(8.2)
11.0(11.0)
8.5(8.3)
7.4(7.8)
9.0(9.13)
8.2(8.2)
7.0(7.0)
6.8(6.22)
5.3(5.3)
7.2(7.2)
10.2(10.2)
8.3(8.3)
7.0 (6.9)
5.6 (5.7)
–
–
–
–
Yellow
Pale green
Yellow
Black
Pale brown
Brown
Brown
Green
Dark green
Brown
Pale brown
Brown
Black
Dia.
Dia.
2.85
4.8
4.9
3.9
1.73
1.2
1.74
5.96
3.7
5.72
1.73
Dia.
Dia.
Dia.
Dia.
Dia.
Dia.
Dia.
10.2(10.8)
13.0(13.2)
10.9(11.3)
11.0(10.9)
7.0(7.0)
10.8(11.0)
12.3(12.4)
19.7(19.9)
12.6(12.6)
12.6(10.2)
12.2(11.9)
10.9(10.8)
17.0(17.0)
13.5(13.5)
22.3(22.3)
11.2(11.2)
8.0(7.9)
[(HL)NiCl(H2O)2]·(3/2)H2O
[(HL)Co(OAc)(H2O)2]H2O
[(HL)2Co(H2O)2]·(1/2)H2O
[(HL)CoCl(H2O)2]·2H2O
[(HL)Cu(OAc)]·H2O
6.3(6.8)
–
–
6.8(6.6)
–
–
7.0(7.0)
–
–
13.5(13.8)
5.9(6.0)
10.9(10.5)
17.5(17.8)
–
3.2
1.2
1.2
1.2
1.8
1.2
1.4
5.4
2.1
4
3.8
1.82
2.3
1.9
2.8
3.2
[(L)Cu2(NO3)2(H2O)]
[(HL)Cu(Cl)(H2O)2]
[(HL)Mn(OAc)(H2O)2]·(3/2)H2O
[(L)2Mn2(H2O)4]
[(HL)FeCl2(H2O)]
[(HL)Ru(OH)Cl(H2O)]·3H2O
[(H2L)ZrOCl2]·7H2O
[(H2L)HfCl4]6H2O
>300
Yellow
Green
Pink
Pink
Pink
220
240
220
138
145
250
165
[(HL)Zn(OAc)(H2O)2]·3H2O
[(HL)2Zn(H2O)]
–
[(HL)ZnCl(H2O)2]
7.0 (7.0)
8.7(8.8)
–
12.9(12.9)
22.8(22.9)
32.9(32.4)
[(L)(HL)La2Cl3(H2O)]·4H2O
Pale green
Orange
[(HL)UO2(OAc)]·2H2O

Table 2
IR spectra (assignments) of the H2L and its metal complexes
Comp. no. OH/H O
hydr.
/H O
2
coord.
ν(H-bonding)
ν(NH)
ν(C O) ν(C N)
ν(C C)
ν(CH C)
Al
ν(C O)
ν(OAc)
ν(M O)
ν(M N)
ν(M Cl)
2
Ar
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
–
3450–3200(br), 3100–2600(br)
3280–2850(br), 2800–2460(br)
3000–2830(br), 2820–2400(br)
3300, 3250 (m), (m)
3300, 3240 (m), (m)
3352, 3270 (m), (m)
3275, 3215 (m), (m)
1662(s)
1630(s)
–
1600(m)
1570(s)
1552(s)
1550(s)
1555(s)
1547(s)
1548(s)
1550(s)
1572(s)
1548(s)
1575(s)
1550(s)
1508(s)
1516(s)
1523(s)
1518(s)
1522(s)
1523(s)
1517(s)
1525(s)
1527(s)
1522(s)
1515(s)
1517(s)
1523(s)
1518(s)
1524(s)
1531(s)
1533(s)
1520(s)
1520(s)
1519(s)
1518(s)
1326(s)
1227(m)
1228(m)
1317, 1222 (m), (m)
1316, 1226 (m), (m) 1605, 1388 (m), (m) 689, 619 (m), (m) 514(m)
1308, 1229 (m), (m)
1308, 1226 (m), (m)
1312, 1230 (m), (m) 1600, 1399 (m), (m) 688, 656 (m), (m) 570(m)
1314, 1208 (m), (m)
1311, 1270 (m), (m)
1306, 1224 (m), (m) 1625, 1393 (m)
1310, 1227 (m), (m)
1345(m)
1311, 1230 (m), (m)
1318, 1224 (m), (m)
1321, 1225 (m), (m)
1341, 1225 (m), (m) 1603, 1395 (m), (m) 677, 637 (m), (w) 520(m)
1309, 1225 (m), (m)
1308, (m)
1308, 1223 (m), (m)
1311, 1223 (m), (m) 1600, 1365 (m), (m) 688, 617 (m), (m) 514(m)
–
–
–
–
–
–
–/3570–3300(br)
–/–/3250–3050(br)
3375(s)/3450–3200(br)/3180–2950(br) 3150–2950(br), 2900–2500(br)
–/3560–3250(br)/3200–3030(br)
–/3560–3300(br)/3250–3070(br)
3550(s)/3560–3320(br)/3280–3100(br) 3080–2780(br), 2760–2425(br)
–/3530–3280(br)
–/–/3350–3120(br)
–/–/3380–3190(br)
–/3520–3260(br)/3230–3030(br)
–/–/3350–3100(br)
3380–3190(br)
–/3580–3280(br)/3250–3125(br)
3363(s)/3600–3200(br)
3390/3580–3225(br)
–/3580–3250(br)/3180–3080(br)
–/–/3350–3190(br)
1605, 1599 (m)
1606, 1596 (m)
1629, 1599 (m)
1595(m)
1595(m)
1632(m)
1596(m)
1629, 1595 (m)
1593(m)
1595(m)
1606, 1599 (m), (m) 1553(s)
1600, 1370 (m), (m) 631(m)
–
–
521(m)
525(m)
517(m)
631(m)
693(m)
–
410(m)
–
–
420(m)
–
–
420(m)
–
–
421(m)
410(m)
410(m)
420(m)
–
3000–2820(br), 2800–2380(br) 3334, 2250 (m), (br)
3050–2820(br), 2800–2370(br)
1702(s)
1661(s)
–
1655(s)
-
1726(s)
1650(s)
–
1648(s)
1633(s)
–
3372, 3275 (m), (m)
3400, 3263 (m), (m)
3389, 3175 (m), (m)
3325, 3250 (m), (m)
3265, 3234 (m), (m)
3325, 3245 (m), (m)
3300, 3185 (m), (m)
3325, 3261 (m), (m)
3391, 3260 (m), (m)
3330, 3250 (m), (m)
3296, 3235 (m), (m)
3396, 3286 (m)
–
–
687, 625 (m), (m) 523(m)
692, 625 (m), (m) 519(m)
3100–2800(br), 2780–2380(br)
3100–2820(br), 2800–2450(br)
3150–2960(br), 2950–2520(br)
3000–2800(br), 2780–2450(br)
3080–2820(br), 2800–2450(br)
3150–2850(br), 2825–2450(br)
3100–2780(br), 2770–2380(br)
3180–2720(br), 2700–2380(br)
3170–2720(br), 2700–2380(br)
3070–2850(br), 2830–2480(br)
3180–2860(br), 2850–2450(br)
3190–2870(br), 2850–2460(br)
3170–2930(br), 2900–2450(br)
3200–2800(br), 2780–2400(br)
–
–
689, 636 (m), (m) 566, 523 (m), (m)
692, 630 (m), (m) 538(m)
691, 651 (m), (m) 518(m)
631, 691 (m), (m) 521
686, 649 (m), (w) 617(m)
694, 617 (m), (m) 545(m)
685, 612 (m), (m) 540(w)
685, 613 (m), (m) 542(m)
–
–
–
–
–
1612(m)
1593(m)
1595(m)
1575(s)
1550(s)
1560(s)
–
1612, 1596 (m), (m) 1551(s)
1662(s)
1660(s)
1655(s)
1650(s)
1650(s)
1629(m)
1597(m)
1597(m)
1598(m)
1594(m)
1551(s)
1551(s)
1551(s)
1552(s)
1545(s)
3406, 3289 (m), (m)
3437, 3289 (m), (m)
3406, 3280 (m), (m)
3466, 3190 (m), (m)
–
–
–
686, 625 (m), (m) 532(m)
687, 625 (m), (m) 528(m)
689, 608 (m), (m) 519(w)405, 375 (m), (m)
–
–/–/3325–3200(br)
–/3500–3320(br)/3300–3180(br)
–/3570–3320(br)
407(m)
–
Strong = (s), medium = (m), broad = (br) and weak = (w).

94
A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
Table 3
UV–vis spectra of the H2L and its metal complexes
Comp no. Molecular formula
λmax (nm)
1
[(H2L)]
[C23H21N3O2]
370 (ε = 8.9 × 10−3 mol−1 cm−1
320 (ε = 7.7 × 10−3 mol−1 cm−1
)
)
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
[(HL)Ni(OAc)]·3H2O
550 (ε = 5 × 10−3 mol−1 cm−1), 420 (ε = 2.6 × 10−4 mol−1 cm−1), 350, 315
565 (ε = 1 × 10−2 mol−1 cm−1), 420 (ε = 2.8 × 10−4 mol−1 cm−1), 360, 315
[(L)Ni(H2O)]
[(HL)NiCl(H2O)2]·(3/2)H2O
[(HL)Co(OAc)(H2O)2]H2O
[(HL)2Co(H2O)2]·(1/2)H2O
[(HL)CoCl (H2O)2]·2H2O
[(HL)Cu(OAc)]·H2O
[(L)Cu2(NO3)2(H2O)]
[(HL)Cu(Cl)(H2O)2]
725, ( = 6.2 × 10−4 mol−1 cm−1), 525 (ε = 3.3 × 10−4 mol−1 cm−1), 450, 360, 315
715 (ε = 5 × 10−3 mol−1 cm−1), 560 (ε = 5 × 10−4 mol−1 cm−1), 460, 365, 315
690 (ε = 6.6 × 10−4 mol−1 cm−1), 505 (ε = 3.3 × 10−4 mol−1 cm−1), 410 (ε = 2.3 × 10−5 mol−1 cm−1), 355, 295
695, 500, 420 (ε = 2.5 × 10−4 mol−1 cm−1), 350, 300
580 (ε = 1 × 10−2 mol−1 cm−1), 430 (ε = 1.7 × 10−4 mol−1 cm−1), 390, 345, 300
570 (ε = 6.2 × 10−4 mol−1 cm−1), 480 (ε = 2.5 × 10−4 mol−1 cm−1), 395 (ε = 2.8 × 10−5 mol−1 cm−1), 345, 315
660, 545 (ε = 3.3 × 10−4 mol−1 cm−1), 450 (ε = 4.0 × 10−5 mol−1 cm−1), 340, 315
[(HL)Mn(OAc)(H2O)2]·(3/2)H2O 625, 520 (ε = 3.3 × 10−4 mol−1 cm−1), 470 (ε = 2.3 × 10−5 mol−1 cm−1), 330, 310
[(L)2Mn2(H2O)4]
[(HL)FeCl2(H2O)]
660, 490 (ε = 6.6 × 10−4 mol−1 cm−1), 415 (ε = 3.7 × 10−5 mol−1 cm−1), 340, 305
680, 520 (ε = 2 × 10−3 mol−1 cm−1), 420 (ε = 5.5 × 10−5 mol−1 cm−1), 345, 315
[(HL)Ru(OH)Cl(H2O)]·3H2O
[(H2L)ZrOCl2]·7H2O
[(H2L)HfCl4]·6H2O
620 (ε = 6.6 × 10−5 mol−1 cm−1), 560 (ε = 4.7 × 10−5 mol−1 cm−1), 470 (ε = 2.2 × 10−5 mol−1 cm−1), 360, 305
390, 345, 300
390,350, 300
355, 315
350, 320
350, 315
320, 315
[(HL)Zn(OAc)(H2O)2]·3H2O
[(HL)2Zn(H2O)]
[(HL)ZnCl(H2O)2]
[(L)(HL)La2Cl3(H2O)]·4H2O
[(HL)UO2(OAc)]·2H2O
460 (ε = 2.3 × 10−3 mol−1 cm−1), 330, 310
coordination between the ligand and the metal ion, the IR
spectrum of the H2L is compared with that of the metal com-
plexes. The ν(OH) of complexes (4), (7), (15 and 16) observed
as strong band at 3375, 3550, 3363 and 3390 cm−1, respec-
tively. The complexes show broad bands in the 3250–2720
and 2950–2370 cm−1, ranges are due to intermolecular and
intramolecular hydrogen bondings. Also, the complexes show
a broad band in the 3600–3200 cm−1 range, which is assigned
to hydrated water molecules except complexes (3), (9, 10), (12,
13), (18 and 19). However, the broad band due to the coordi-
nated water molecules appears in the 3380–2950 cm−1 range
except complexes (2), (8), (15, 16) and (21) [27,28]. The ν(NH)
appears medium bands at 3466–3296 and 3289–3175 cm−1
ranges [27,28]. The complexes show a strong band in the
1726–1633 cm−1 range (Table 2), which is assigned to ν(C O)
group except complexes (2–4), (7), (9), (12), (15 and 16) [29,30],
however, the medium and strong bands appear in the 1632–1593,
1575–1545 and 1533–1508 cm−1 ranges is due to ν(C N),
ν(C C)Ar and ν(CH C) vibrations, respectively [25,31]. Com-
plexes (2), (5), (8), (11), (17) and (21) show νa(CO2) = 1600,
1605, 1600, 1625, 1603 and 1602 cm−1 and νs(CO2) = 1370,
1388, 1399, 1393, 1395 and 1365 cm−1, respectively suggesting
monodentate acetate group [32–34]. Complex (9) shows strong
and medium bands at 1410, 1360, 1208, 823 and 763 cm−1
(Table 2), which is assigned to a bridging and terminal nitrate
group[33,35,36]. Themediumbandappearsat1345–1208 cm−1
range corresponds to ν(CO) group [25,27]. The complexes
(4), (7), (10), (13–16), (19 and 20) show a medium band at
421–405 and 390–375 cm−1 ranges, corresponding to termi-
nal and bridging chloride atoms, however, complex (15) shows
a medium band at 760 cm−1 is assigned to ν(ZrO) vibration
[37]. Complex (21) shows a medium band at 940 cm−1 is due to
O U O group [37]. The bonding of the metal ions to the H2L
through the oxygen and nitrogen atoms is further supported by
the presence of new medium and weak bands at 694–608 and
566–514 cm−1ranges, are due to ν(M O) and ν(M N), respec-
tively [33,38]. The above results together with the elemental
analyses indicated that, the hydrazone coordinated to the metal
ion, via the carbonyl oxygen of the hydrazide moiety, carbonyl
oxygen of the dibenzoylmethane moiety in enolic or ketonic
form and azomethine nitrogen atom.
4.4. Magnetic moments
The room temperature magnetic moments of the complexes
(2–21) are shown in Table 1. Nickel(II) complexes (2 and 3)
show diamagnetic values confirming square planar geometry
around the nickel(II) ion However, complex (4) shows value
2.85 μB., indicating octahedral geometry [33,37–41]. Cobalt(II)
complexes (5–7) show values in the 4.8–3.9 μB range (Table 1),
indicating high-spin octahedral cobalt(II) complexes [16]. The
magnetic moments for the copper(II) complexes (8, 9 and 10)
are 1.73, 1.2 and 1.74 μB, respectively. The value of complex
(9) is well below the spin-only value (1.73μB), indicating spin-
exchange interactions take place between the copper(II) ions
[38]. However, the values of the other complexes correspond to
one unpaired electron in a square planar or octahedral structure
[16]. The magnetic moment values for manganese(II) complexes
(11 and 12) are 5.69 and 3.7 μB, suggest octahedral geom-
etry around the manganese(II) ion [16]. The low moment of
(12) may be ascribed to superexchange takes place between
manganese(II) ions. Iron(III) complex (13) shows value 5.4
μB, indicating a high-spin iron(III) octahedral geometry [5].
Ruthenium(III) complex (14) shows a magnetic value 2.1 μB.,
indicating an octahedral structure [42]. Zirconium(IV) complex
(15), hafnium(IV) complex (16), zinc(II) complexes (17–19),

A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
95
lanthanum(III) complex (20) and uranyl complex (21) show
diamagnetic values.
show two bands in the 295–315 and 330–365 nm ranges which
are assigned to intraligand transition [16,43]. The nickel(II)
complexes(2)and(3)showtwobandsat420and550 nmand420
3
3
and 565 nm are due to 3T1 → T2 and 3T1(F) → T2(P) transi-
tions, indicating square planar environment around the nickel(II)
ion [44,45]. However, complex (4), shows bands at 450, 525
4.5. Electronic spectra
The electronic spectral data of the H2L and its metal
complexes are summarized in Table 3. The H2L shows
two bands at 370 nm (ε = 8.9 × 103 mol−1 cm−1) and 320 nm
(ε = 7.7 × 103 mol−1 cm−1), which may be assigned to the
n → ␲* and ␲ → ␲* transitions, respectively, the complexes
3
and 725 nm, which are attributable to 3A2g(F) → T1g(P) (υ3),
3A2g(F) → T1g(F) (υ2) and A2g(F) → T2g(F) (υ1) transi-
tions, respectively indicating an octahedral nickel(II) complex
[16,46,47]. The υ2/υ1 ratio for the complex is 1.38 which is less
3
3
3
Fig. 1. Structural representation of the complexes.

96
A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
Fig. 1. (Continued ).
than the usual range of 1.5–1.75, indicating distorted octahedral
nickel(II) complexes [33,37,40,48,7]. The cobalt(II) complexes
(5–7) show bands in the 410–460, 500–550 and 690–715 nm
transfer transition while the last band is considered to arise from
6
4
the A1 → T1 transition, these bands suggest, distorted octa-
hedral geometry around the iron(III) [52,54]. Ruthenium(III)
complex (14), shows bands at 470, 560 and 620 nm, respec-
tively, are due to LMCT transition and the last band is assigned
4
4
4
4
ranges, are assigned to T1g (F) → T1g (P), T1g (F) → A2g
4
and 4T1g(F) → T2g(F), transitions, respectively, corresponding
2
2
to high-spin cobalt(II) octahedral complexes [40,49]. The cop-
per(II) complexes (8) and (9) show different bands (Table 3) at
390, 430 and 580 nm and 395, 480 and 570 nm, corresponding to
to T2g → A2g transition. The band position are similar to
those observed for other octahedral ruthenium(III) complexes
[55–58]. Zirconium(IV) complex (15), hafnium(IV) complex
(16), zinc(II) complexes (17–19), lanthanum(III) complex (20)
and uranyl(VI) complex (21) show bands (Table 3) correspond-
ing to intraligand transitions [59,60].
2
2
2
2B1g → B2g, 2B1g → Eg and 2B1g → A1g, respectively, sug-
gesting square planar geometry [50,51]. However, copper(II)
complex (10) shows bands at 450, 545 and 660 nm, are assigned
2
2
2
2
to ligand → metal charge transfer, B1 → E and B1 → B2
transitions respectively, indicating a distorted octahedral struc-
ture [10,44,52]. Manganese(II) complexes (11) and (12) show
bands at 470, 520 and 625 nm and 415, 490 and 660 nm,
4.6. Electron spin resonance
The ESR spectra of solid copper(II) complexes (9) and
(10) at room temperature are characteristic of d9, configuration
and having an axial and non-axial types of a d(x2−y2) ground
state [61,62]. The g-values suggest square planar or octahedral
respectivelyarecorrespondingto6A1g → Eg, 6A1g → T2g and
4
4
4
6A1g → T1g transitions which are compatible to an octahedral
geometry around the manganese(II) ion [53]. Iron(III) complex
(13) shows bands at 420, 520 and 680 nm, are due to charge
geometries [30] and the complex (9) shows g > g > 2.0023,
ꢀ
⊥

A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
97
Table 4
Thermal data for the metal complexes
Comp. no.
Temperature (◦C)
DTA (peak)
Endo
TGA (Wt. loss %)
Assignment
Exo
Calc.
Found
4
70
210
370
450
490
65
215
300
350
420
600
90
200
350
450
550
85
220
450
600
75
endo
endo
–
–
–
endo
endo
–
–
–
–
–
exo
exo
exo
–
5.2
14.5
5.0
15.1
Loss of hydrated water (1.5·H2O)
Loss of coordinated water (2H2O) + one chlorine atom
17.78
9.0
13.43
18.1
8.65
13.8
Decomposition with the formation of NiO
Loss of hydrated water (3H2O)
Loss of coordinated water, chloride atom and hydroxyl group
14
15
–
exo
exo
exo
exo
–
–
39.51
18.66
12.92
39.43
19.2
13.2
Decomposition with the formation of Ru2O3
Loss of hydrated water (7H2O)
Loss of chloride atom (2Cl)
endo
endo
–
–
–
endo
endo
–
–
exo
exo
exo
–
25.76
13.5
20.53
25.5
14.0
21.0
Decomposition with the formation of ZrO2
Loss of hydrated water (6H2O)
Loss of, chloride atom (4Cl)
16
17
–
exo
exo
–
–
–
exo
exo
exo
–
38.3
9.24
6.78
11.93
38.1
9.63
6.9
Decomposition with the formation of HfO2
Loss of hydrated water (3H2O)
Loss of coordinated water (2H2O)
Loss of acetate group
endo
endo
endo
–
–
–
140
320
380
450
550
12.0
18.69
18.5
Decomposition with the formation of ZnO
indicating square planar geometry around the copper(II) ion
[21,63,64], however, complex (10) shows non-axial type
gx > gy > gz > 2.0023 with (gy − gz)/(gx − gy) < 1 = 0.23, indi-
cating a d(x2−y2) ground state [21]. The ESR parameters
for complex (9) are g = 2.22, g = 2.09 and giso = 2.13,
4.7. Thermal analyses (DTA and TGA)
The DTA and TGA dehydrating curves for complexes (4,
and 14–17) show that, the complexes are thermally stable
up to 50 ◦C. Dehydration is characterized by endothermic
peaks within the temperature 65–90 ◦C range [58,73,74]. Com-
plexes (4, 14 and 17) show endothermic peak at 210, 215 and
140 ◦C, respectively is due to the loss of coordinated water
molecules. Another endothermic peak was observed around
200 ◦C (Table 4), corresponds to the loss of chlorine atoms,
however complex (17) shows endothermic peak at 320 ◦C, is
due to the loss of acetate group. The results were confirmed by
TGA data (Table 4). The product is stable up to 300 ◦C when
the organic constituents, of the complexes start decomposing,
finally leaving the metal oxides (490–600 ◦C) [75]. The thermal
decomposition of complex (4) can be represented as follows:
ꢀ
⊥
A = 160 G, A = 15 G and Aiso = 63.3 G, G = 2.44, α2 = 0.71,
ꢀ
⊥
g /A = 134.5 cm−1, K = 0.76, K = 1.05 and K = 0.96, β2 =
ꢀ
ꢀ
ꢀ
⊥
1
0.80 and β2 = 1.5, 2B = −156 and a2d = 66% and for complex
(10), are gx = 2.21, gy = 2.08 and gz = 2.05 [65]. Complex (9)
shows G is 2.44, indicating spin-exchange interactions take
place between the copper(II) ions [65]. This is confirmed from
the magnetic moment. The g /A value for complex (9) is
ꢀ
ꢀ
(134.5 cm−1) lies just within the range expected for square
planar complexes [66]. The g -value reported here is 2.22 in
ꢀ
complex (9) indicating considerable covalent bonding charac-
ter [30,63,67]. The calculated value of α2 of complex (9) is
0.71, suggesting considerable covalent bonding [21,68,69]. K-
value for the complex (9) is 0.96, which confirmed covalent
nature [69,70]. Also, the complex (9) shows β12 = 0.8, indicat-
ing a moderate degree of covalancy in the in-plane ␲-bonding,
while B2 = 1.5, indicates the ionic character of the out-of plane
␲-bonding [71,72]. In complex (9) the isotropic coupling con-
stant is Aiso = −63.3 G, and the parallel component of the dipolar
coupling is 2B = −156G, giving orbital population 66%, indicat-
ing a d(x2−y2) ground state [66]. However, the ESR spectrum of
manganese(II) complexes (11 and 12) show isotropic type with
giso = 2.022 and 2.033, respectively typical to manganese(II)
octahedral structure.
70 ◦C
3
[(HL)NiCl(H2O)2]32 H2O−→ [(HL)NiCl(H2O)2] + H2O,
2
◦
[(HL)NiCl(H2O) ]2−10→C[(HL)Ni] + 2H2O + Cl,
[(HL)Ni]4−90→CNiO + volatile organic residue
2
◦
The thermal data of the complexes are shown in Table 4.
4.8. Antibacterial and antifungal screening
The results obtained are presented in Table 5. It is observed
that, the activity of the metal complexes increases with increase

98
A.S. El-Tabl et al. / Spectrochimica Acta Part A 71 (2008) 90–99
Table 5
The percent effect of the H2L and its metal complexes on microorganisms at different concentrations
No. of comp
At 250 ␮g/mL
At 200 ␮g/mL
At 175 ␮g/mL
At 150 ␮g/mL
At 125 ␮g/mL
Fungi
Bacteria
Fungi
Bacteria
Fungi
Bacteria
Fungi
Bacteria
Fungi
Bacteria
1
3
5
6
8
9
11
18
25
32
31
32
52
35
29
37
50
43
54
48
35
38
43
52
19
25
26
26
45
28
23
31
41
35
45
39
28
30
35
45
12
18
20
19
37
19
18
25
30
28
39
28
20
24
28
37
0
12
14
13
30
13
13
18
24
20
27
17
15
18
23
29
0
0
0
17
15
20
13
11
13
15
22
0
20
11
0
14
The percent effect = (diameter of zone/diameter of Petri dish) × 100; Fungi, Aspergillus niger; Bacteria, E. coli; DMF was used as antimicrobial inert solvent.
in the concentration of the solutions. All the metal complexes
are more potent bactericides and fungicides than the H2L. This
enhancement in the activity can be explained on the basis of
chelation theory [76,77]. The results showed that, copper(II)
complex (8) shows higher antifungal activity than the other
complexes in all concentrations, however, cobalt(II) complexes
(5) shows higher antibacterial activity than the other complexes
in all concentrations except at low concentration (125 ␮g/mL).
Zn(II) complex (18) shows higher antibacterial at 200 ␮g/mL
and 125 ␮g/mL concentrations. The order of activity of the all
complexes is 18 > 5 > 6 > 8 > 9 > 11 > 3 > 1. The variation in the
activity of different complexes against different microorganisms
depends either on the impermeability of the cells of the microbes
or differences in ribosome’s in microbial cells [78]. The antibac-
terial and antifungal activities of the hydrazone ligands and their
metal complexes are screened using the disk diffusion [79].
[11] A. Bacchi, A. Bonardi, M. Carcelli, P. Mazza, P. Pelagati, C. Pelazzi, G.
Pelizzi, C. Solimano, F. Zani, J. Inorg. Biochem. 69 (1998) 101.
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(2003) 349.
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25.
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[15] M.M. Mohammed, A. Azzam, MSc Thesis, Faculty of Science, Menoufia
University, Egypt, 2005.
[16] A.S. El-Tabl, F.A. El-Saied, A.N. Al-Hakimi, Trans. Met. Chem. 32 (2007)
689.
[17] K.B. Gudasi, S.A. Patil, R.S. Vadvavi, R.V. Shenoy, M. Nethaji, Trans.
Met. Chem. 31 (2006) 586.
[18] K.B. Gudasi, M.S. Patel, R.S. Rashmi, V. Shenoy, S.A. Patil, M. Nethaji,
Trans. Met. Chem. 31 (2006) 580.
[19] R.C. Maurya, R. Verma, D. Sutradha, Synth. React. Inorg. Met. Org. Chem.
33 (2003) 435.
[20] A.S. El-Tabl, R.M. Issa, J. Coord. Chem. 57 (2004) 509.
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73 (1999) 245.
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5. Short conclusion
Metal complexes of new hydrazone derived from diketone
have been prepared and characterized by elemental, spectral,
thermal and magnetic measurements. Modes of coordination
depend into the nature of metal ion and the medium of the reac-
tion. The complexes are non-electrolytes and have covalent bond
character. Antibacterial and antifungal tests have been carried
out.
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