Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of N′-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide

Article abstract of DOI:10.1016/j.saa.2008.09.015

Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of furan-2-carbaldehyde 4-methoxy-N-anilinoacetohydrazone were synthesized and characterized by elemental and thermal (TG and DTA) analyses, IR, UV-vis and ¹H NMR spectra as well as magnetic moment and molar conductivity. Mononuclear complexes are obtained with 1:1 molar ratio except complexes 3 and 9 which are obtained with 1:2 molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand behaves as a neutral bidentate one and coordination occurs via the carbonyl oxygen atom and azomethine nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the enolic oxygen atom, azomethine nitrogen atom and the oxygen atom of furan ring. Moreover, the ligand behaves as a neutral tridentate and coordination occurs via the carbonyl oxygen, azomethine nitrogen and furan oxygen atoms as well as a monobasic bidentate and coordination occurs via the enolic oxygen atom and azomethine nitrogen atom. The electronic spectra and magnetic moment measurements reveal that all complexes possess octahedral geometry except the copper complex 10 possesses a square planar geometry. The thermal studies showed the type of water molecules involved in metal complexes as well as the thermal decomposition of some metal complexes.

Full text of DOI:10.1016/j.saa.2008.09.015

Spectrochimica Acta Part A 72 (2009) 291–297
Contents lists available at ScienceDirect
Spectrochimica Acta Part A: Molecular and
Biomolecular Spectroscopy
journal homepage: www.elsevier.com/locate/saa
Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of
Nꢀ-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide
Sanaa M. Emam, Fathy A. El-Saied∗, Saeyda A. Abou El-Enein, Heba A. El-Shater
Chemistry Department, Faculty of Science, El-Menoufia University, Shebin El-Kom, Egypt
a r t i c l e i n f o
a b s t r a c t
Article history:
Cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) complexes of furan-2-carbaldehyde 4-methoxy-
N-anilinoacetohydrazone were synthesized and characterized by elemental and thermal (TG and DTA)
analyses, IR, UV–vis and 1H NMR spectra as well as magnetic moment and molar conductivity. Mononu-
clear complexes are obtained with 1:1 molar ratio except complexes 3 and 9 which are obtained with 1:2
molar ratios. The IR spectra of ligand and metal complexes reveal various modes of chelation. The ligand
behaves as a neutral bidentate one and coordination occurs via the carbonyl oxygen atom and azomethine
nitrogen atom. The ligand behaves also as a monobasic tridentate one and coordination occurs through the
enolic oxygen atom, azomethine nitrogen atom and the oxygen atom of furan ring. Moreover, the ligand
behaves as a neutral tridentate and coordination occurs via the carbonyl oxygen, azomethine nitrogen
and furan oxygen atoms as well as a monobasic bidentate and coordination occurs via the enolic oxygen
atom and azomethine nitrogen atom. The electronic spectra and magnetic moment measurements reveal
that all complexes possess octahedral geometry except the copper complex 10 possesses a square planar
geometry. The thermal studies showed the type of water molecules involved in metal complexes as well
as the thermal decomposition of some metal complexes.
Received 4 June 2008
Received in revised form
15 September 2008
Accepted 26 September 2008
Keywords:
Transition metal complexes
Acetohydrazide
Furan
Spectral analysis
© 2008 Elsevier B.V. All rights reserved.
1. Introduction
In the present article a number of new metal complexes of
cobalt(II), nickel(II), copper(II), zinc(II) and hafnium(IV) with a new
Hydrazones and their metal complexes possessing pronounced
biological and pharmaceutical activities as antitumor [1–3], antimi-
crobial [4], antituberculosis [5] and antimalarial agents [6].
Hydrazones play an important role in improving the antitumor
selectivity and toxicity profile of antitumor agents by form-
ing drug carrier systems employing suitable carrier proteins [7].
They also employe as extracting agents in spectrophotometric
determination of some ions [8–10] and spectrophotometric deter-
mination of some species in pharmaceutical formulations [11], as
well as uses in catalytic processes [12,13] and wastewater treat-
ment [14]. Hydrazones, such as pyridoxal isonicotinoylhydrazone,
salicylaldehyde benzoylhydrazone and 2-pyridyl carboxaldehyde-
2-thiophene carboxaldehyde hydrazone, act as orally effective
drugs for the treatment of iron overload diseases or genetic dis-
eases ␤-thalassemia [15,16]. Metal complexes of hydrazones have
found applications in various chemical processes like nonlinear
optics, sensors, etc. [17], and have been used in the separa-
tion and concentration of palladium and platinum in road dust
[18].
hydrazone ligand Nꢀ-(furan-3-ylmethylene)-2-(4-methoxyphe-
nylamino)acetohydrazide (HL). The chemical formulations for
ligand and its metal complexes were characterized using various
analytical, spectroscopic techniques such as infrared, nuclear
magnetic resonance, electronic spectra and magnetic moment
measurements as well as molar conductance measurements and
thermal analyses.
2. Experimental
2.1. Instrumentation and measurements
Elemental microanalyses (C,H) were determined in the micro
analytical unit of Cairo University, Egypt. Metals were determined
by complexmetric methods [19]. The IR spectra were measured
using KBr discs of FT-IR 1650 Perkin-Elmer spectrophotometer.
Electronic spectra were recorded in Nujol mulls using Perkin-
Elmer 550. The molar conductivity measurements of complexes in
(1 × 10−3 M) DMF solution were measured at 25 ◦C with a Bibby
conductometer type MCl. The 1H NMR spectrum of the ligand
was recorded using varian unity-300 MHz spectrometer DMSO-
d6 using. The thermal analyses (DTA and TG) were carried out
in air using a Shimadzu DT-30 thermal analyzer in air from
∗
Corresponding author.
E-mail address: Fathi Elsaied@yahoo.com (F.A. El-Saied).
1386-1425/$ – see front matter © 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.saa.2008.09.015

292
S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
Fig. 1. Infrared spectrum of ligand HL.
room temperature to 800 ◦C at a heating rate of 10 ◦C/min. Mag-
netic susceptibilities were measured at 27 ◦C using the modified
Gouy method with a Johnson Matthey magnetic susceptibility bal-
2.2.3. Preparation of the hydrazone ligand 2-(4-methoxyphenyl-
amino)-Nꢀ-(furan-2-yl-methylene)acetohydrazide
Nꢀ-(furan-3-ylmethylene)-2-(4-methoxyphenylamino)aceto-
hydrazide was prepared by mixing an eqimolar amounts of
ance. Magnetic moments were calculated using equation:ꢀeff
=
ꢀ
2.84 XMcorr
T
2-(4-methoxy
phenylamino)acetohydrazide
with
furan-2-
carbaldehyde. The reaction mixture was heated at 60 ◦C with
stirring for 4 h. The obtained product was filtered off, washed with
ethanol and dried under vacuum over anhydrous CaCl2.
2.2. Preparation of the ligand and its metal complexes
2.2.1. Preparation of ethyl 2-(4-methoxyphenylamino)acetate
4-Methoxyaniline (1.23 g, 1 mmol in 5 mL EtOH) was added to
a solution of ethylchloroacetate (1.22 g, 1 mmol in 10 mL of EtOH).
Sodium acetate trihydrate (1.36 g, 1 mmol) dissolved in 15 mL dis-
tilled water was added to the mixture, then, it was refluxed with
stirring for 6 h. The product was poured on crushed ice, and the
solid precipitate which is formed was filtered off, washed several
times with distilled water and dried over anhydrous CaCl2.
2.2.4. Preparation of metal complexes
The metal complexes were prepared by the addition of a hot
ethanol solution of ligand (HL) to an equimolar amount of the metal
salt. The appropriate reaction mixture was stirred and heated at
80 ◦C for 3 h. The separated complex was filtered off, washed several
times with ethanol, and dried under vacuum in the presence of
anhydrous CaCl2.
2.2.2. Preparation of 2-(4-methoxyphenylamino)acetohydrazide
2.3. Microbiology: bacteria media
Hydrazine hydrate (2.5 g, 5 mmol) was added drop wise to
a
solution of ethyl 2-(4-methoxyphenylamino)acetate (2.09 g,
Nutrient agar medium was prepared (g/L distilled water) with
5 g NaCl, 5 g peptone, 3 g beef extract, 15 g agar. The pH of
the medium at 7, this medium was then sterilized by auto-
claving at 120 ◦C for 15 min. After cooling to 45 ◦C the medium
was poured into 90-mm diameter Petri dishes (approximately
1 mmol) in 30 mL EtOH. The mixture was refluxed with stirring for
3 h, and then left to cool at room temperature. The formed precip-
itate was filtered off, washed several times with EtOH and dried
over anhydrous CaCl2.
Table 1
Elemental analysis, colour and molar conductivity for ligand and its metal complexes.
No.
Compounds
Colour
Salt and molar ratio (ML)
ꢁaM (ohm−1 cm2 mol−1
)
Elemental analysis (calcd.) (%)
C%
H%
M%
1
2
3
4
5
6
7
8
HL
Pale brown
Dark brown
Dark brown
Brown
–
–
61.0(61.5)
34.8(34.8)
46.6(46.1)
43.7(44.6)
36.7(36.8)
30.9(30.8)
44.4(44.5)
37.0(36.4)
40.4(40.8)
44.5(45.5)
45.2(44.6)
29.1(28.3)
5.3(5.5)
4.4(4.6)
4.8(4.1)
4.8(5.0)
4.6(4.6)
4.6(4.6)
5.3(5.1)
4.0(4.6)
4.6(4.9)
4.7(4.9)
4.9(4.2)
3.2(2.5)
–
[Co(L)Br(H2O)2]·2H2O
CoBr2(1:1)
36.0
10.2
23.0
38.0
38.0
38.5
18.3
38.4
18.4
38.0
27.3
11.8(12.2)
9.0(8.1)
13.2(13.7)
12.4(12.9)
10.2(10.8)
12.4(12.1)
12.9(13.8)
8.3(7.7)
15.2(14.8)
9.2(8.7)
–
[CO(HL)2(NO3)2]
Co(NO3)2(1:1)
Co(OAc)2(1:1)
NiCl2(1:1)
Ni(NO3)2(1:1)
Ni(OAc)2(1:1)
CuCl2(1:1)
Cu(NO3)2(1:1)
Cu(OAc)2(1:1)
Zn(NO3)2(1:1)
HfCl4(1:1)
[Co(L)(OAc)(H2O)2](1/4)H2O
[Ni(HL)Cl2(H2O)2]·H2O
[Ni(HL)(NO3)2(H2O)2]·3H2O
[Ni(HL)(OAc)2(H2O)]·H2O
[Cu(HL)Cl2(H2O)2]·H2O
[Cu(HL)2(NO3)2]·5H2O
[Cu(L)(OAc)(H2O)]·H2O
[Zu(HL)2(NO3)2]·.H2O
[Hf(HL)Cl4]
Brown
Dark brown
Dark brown
Dark brown
Brown
Dark brown
Brown
9
10
11
12
Brown

S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
293
Table 2
Infrared spectral bands for ligand and its metal complexes.
No.
Compounds
ꢂ(H2O)
ꢂ(N–H)
ꢂ(C O)
ꢂ(C N)
ꢂ(OAc/NO3)
ꢂ(furan)
ꢂ(M–O)
ꢂ(M–N)
1
2
3
4
5
6
7
8
HL
–
3390
3388, 3203, 3120
3390, 3196
3390, 3215, 3140
3380, 3217
3380, 3200, 3120
3380, 3250
3380, 3200, 3120
3200, 3120
3350, 3220, 3127,
3135
3390, 3200, 3208
3390, 3230, 3160
1672
–
1619
–
1617
1622
1631
1617
1620
–
1625
1609,1560
1551
1600,1556
1546
1560
1560
1575
1565
1605,1580
1550
–
–
590
561
590
562
590
590
618
590
592
593
591
591
–
531
523
500
525
524
521
510
560
523
523
519
–
450
450
460
426
450
450
470
460
417
440
450
[Co(L)Br(H2O)2]·2H2O
[Co(HL)2(NO3)2]
–
1384, 1305
1585, 1405
–
1383, 1290
1580, 1403
–
1385, 1300
1600, 1396
1385, 1304
–
[Co(L)(OAc)(H2O)2](1/4)H2O 3380
[Ni(HL)Cl2(H2O)2]·H2O
[Ni(HL)(NO3)2(H2O)2]·3H2O
[Ni(HL)(OAc)2(H2O)]·H2O
[Cu(HL)Cl2(H2O)2]·H2O
[Cu(HL)2(NO3)2]·5H2O
[Cu(L)(OAc)(H2O)]·H2O
[Zn(HL)2(NO3)2]·H2O
[Hf(HL)Cl4]
3380
3380
3390
3420
3423
3421
3390
–
9
10
11
12
1622
1655
1615
20 mL for each) and incubated at 37 ◦C. After a few hours, Petri
dishes were stored at 4 ◦C. Esherichia coli was spread over each
dish by using sterile bent loop rod. Disks were cut by steril-
ized cork borer and then taken by sterilized needle. The resulted
pits are sites for the tested compounds. The plates are incu-
bated at 37 ◦C for 48–72 h and then any clear zones present were
detected.
behave as non-electrolytes, indicating that the anions are directly
attached to the metal ion [20,21].
The most important spectral bands and their assignments for
metal complexes are depicted in Table 2. Table 2 shows that, the
infrared spectra of complexes 3, 5, 6, 8, 9, 11 and 12 (Figs. 4 and 5)
display the bands corresponding to ꢂ(C O) and ꢂ(C N) in the
ranges 1655–1617, 1615–1644 cm−1, respectively, which are lower
than that of the free ligand, indicating that the carbonyl oxygen
atom and the azomethine nitrogen atoms are involved in coordi-
nation. Moreover, the spectra of these complexes show that the
bands corresponding to NH groups and furan ring slightly affected
or remain at the some positions on complexation indicating that
the NH groups and furan oxygen atom do not participate in coordi-
nation. The above arguments indicate that the ligand behaves as a
neutral bidentate one and coordination occurs via the carbonyl oxy-
gen and azomethine nitrogen atoms. The infrared spectra of metal
complexes 2, 4 and 10 reveal that the band due to the carbonyl group
disappears upon complexation. Moreover a band corresponding to
one of the N–H groups also disappears and a new band appears in
the range 1609–1600 cm−1, assigned to ꢂ(O–C N). This could be
explained on the basis that the ligand reacts entirely in its enol
form. The spectra also show that the band due to furan ring does
not show any shift in the spectra of complexes 2 and 4, whereas
in the spectrum of complex 10 this band shows a slight shift. This
indicating that the furan oxygen atom does not participate in the
coordination in the former complexes whereas it is involved in
coordination in the latter complex. Table 2 also shows that the
spectrum of complex 7 shows bands in the ranges 3380–3200
and 3120, 1631, 1560 and 618 cm−1 the first three bands assigned
to uncoordinated NH groups and the latter three bands assigned
to coordinated ꢂ(C O), coordinated ꢂ(C N) and coordinated oxy-
gen furan atom, respectively. This indicates that the ligand in this
complex behaves as a neutral tridentate one, coordinating via the
carbonyl oxygen, azomethine nitrogen and furan oxygen atoms. The
presence of water molecules within the coordination sphere in the
hydrate complexes 2, 4–8 and 10 is supported by the appearance
of infrared spectral bands in the ranges 3423–3380, 960–820 and
670–640 cm−1, assigned to OH stretching, H2O rocking and H2O
wagging, respectively [22]. The absence of the latter two bands
in the spectra of the rest complexes 2, 9 and 11 indicating that
the water in these complexes is lattice rather than coordinated
[23]. Extensive infrared spectral studies reported on metal acetate
complexes, indicate that the acetate ligand may coordinate to a
metal ion in either a monodentate, bidentate or bridging manner.
The ꢂa(COO) and ꢂs(COO) of the free acetate ions are at 1560 and
1416 cm−1, respectively. In monodentate ꢂ(C O) is found at higher
energy than ꢂs(C–O) is lower than ꢂs(CO2). As a result, the separa-
tion between the two ꢂ(C O) bands is much larger in monodentate
complexes than the free ion. The opposite trend is observed in
3. Results and discussion
The most diagnostic infrared spectral bands of the ligand HL are
listed in Table 2. The spectrum of the ligand (Fig. 1) reveals bands
at 3388, 3203, 3120, 1672, 1625 and 590 cm−1. The first three bands
are assigned to ꢂ(NH) groups while the last three bands are assigned
to ꢂ(C O), ꢂ(C N) and furan ring, respectively.
The 1H NMR spectrum of the ligand shows signals at 11.43, 11.36,
8.15, 7.9 and multiple signals within 7.81–6.53 ppm. These signals
are assigned, to ı(H–NCH2), ı(H–N–N), ı(N CH) as well as aromatic
and furan protons, respectively.
The elemental analyses (Table 1), infrared spectral bands
(Table 2) and 1H NMR data are compatible with the structure of
HL as shown in Fig. 2.
The reaction of the ligand HL with different metal salts: Co(II),
Ni(II), Zn(II) and Hf(IV) ions in 1:1 molar ratio in ethanol pro-
duced 1:1 metal complexes with stoichiometric is shown in Table 1
and chemical formulations are shown in Fig. 3. These air stable
metal complexes are non-hygroscopic, partially soluble in water
and most organic solvents except, in DMF and DMSO are freely sol-
uble. The values of molar conductivities in DMF (10−3 M) solutions
are depicted in Table 1. These values show that all metal complexes
Fig. 2. Nꢀ-(furan-2-ylmethylene)-2-(4-methoxyphenylamino)acetohydrazide.

294
S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
Fig. 3. Structural representation of the complexes.
bidentate acetate coordination; the separation between ꢂ(COO)
bands is smaller than of the free ion. For bridging acetate with
both two oxygen atoms coordinated as in copper(II) acetate, how-
ever the two ꢂ(COO) bands are close to the free ion values [21,24].
The infrared spectra of the acetate complexes reveal two bands in
the ranges 1600–1580 and 1405–1396 cm−1, assignable to ꢂa(COO)
and ꢂs(COO) in monodentate coordination. Further the acetato
complexes exhibit ı(COO) near 720 cm−1 which is considered a
diagnostic for monodentate acetate groups.
3.1. Magnetic moments and electronic spectral data for metal
complexes
The electronic absorption spectral bands as well as the room
temperature magnetic moments (ꢀeff B.M.) per a metal atom of
the metal complexes are listed in Table 3.
Octahedral, tetrahedral and square planar cobalt(II) complexes
show magnetic moment values between 4.7–5.2, 4.2–4.8 and
2.2–2.9 B.M., respectively. The values of ꢀeff of cobalt(II) complexes
2–4 at room temperature were 4.8, 4.9 and 4.5 B.M., respec-
tively. These values are consistent with an octahedral geometry
around the cobalt(II) ion. The considerably high values ruled
out spin–spin interaction between cobalt(II) ions. The electronic
spectra of cobalt(II) complexes display two bands in the ranges
702–700 and 650–602 nm (Fig. 6). These bands may be assigned to
The infrared spectra of nitrato metal complexes 3, 6, 9 and 11
show two bands at 1305–1290 and 1385 cm−1, assigned to ꢂ1 and
ꢂ4 modes of nitrate group, indicating that the nitrate group is ter-
minally bonded monodentate nitrate group. The infrared spectra
of complexes show two new bands at 560–500 and 470–417 cm−1
,
assigned to ꢂ(M–O) and ꢂ(M–N), respectively [21].

S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
295
Fig. 4. Infrared spectrum of complex (3)
4
4
4
4
Table 3
the electronic T1g(F) → T2g(F) and T1g(F) → A2g(F) transitions,
respectively, suggesting a tetragonally distorted octahedral geom-
etry around cobalt(II) ion [22,25].
Magnetic moment values and electronic spectral bands for metal complexes.
No.
Compounds
ꢀeff (B.M.) (per
metal atom)
d–d transitions (nm)
The room temperature magnetic moment values for nickel(II)
complexes 5–7 were 2.85, 2.9 and 3.2 B.M., respectively. These
values are consistent with two unpaired electron configuration.
The considerably high values also ruled out spin–spin interaction
between nickel(II) complexes and ruled out square planar geometry
around nickel(II) ion. The electronic spectra of nickel(II) complexes
(Fig. 7) reveal two bands in the ranges 630–610 and 540–504 nm,
2
3
4
5
6
7
8
9
10
[Co(L)Br(H2O)2]·2H2O
[Co(HL)2(NO3)2]
4.80
4.90
4.50
2.85
2.90
3.20
1.95
1.97
2.31
700(w, br), 650
702(w, br), 602
600, 558
610(br), 518
630(br), 540
615(br), 504
800(br), 605
708, 626, 604
584, 568
[Co(L)(OAc)(H2O)2](1/4)H2O
[Ni(HL)Cl2(H2O)2]·H2O
[Ni(HL)(NO3)2(H2O)2]·3H2O
[Ni(HL)(OAc)2(H2O)]·H2O
[Cu(HL)Cl2(H2O)2]·H2O
[Cu(HL)2(NO3)2]·5H2O
[Cu(L)(OAc)(H2O)]·H2O
assigned to 3A2g(F) → T1g(F)(ꢃ2) and 3A2g(F) → T1g(P)(ꢃ3) transi-
tions, respectively, in pseudo-octahedral nickel(II) complexes [26].
The room temperature magnetic moment values for copper(II)
complexes 8–10 were 1.95, 1.97 and 2.31 B.M., respectively. These
values close to the spin-only value for an unpaired spin (∼1.73 B.M.).
The electronic spectra of copper(II) complexes 8 and 9 exhibit a
3
3
Fig. 5. Infrared spectrum of complex (4)

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S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
3.2. ESR spectra of copper(II) complexes
The ESR spectra of the copper(II) complexes 8 and 10 were
recorded in polycrystalline state at room temperature. The ESR
spectrum of the copper(II) complex 10 exhibited unresolved only
one isotropic signal at high field. The isotropic g value of the com-
plex is 2.117 [30]. The ESR spectrum of the copper(II) complex 8
exhibited anisotropic signals with g = 2.379 and g = 2.091, which is
ꢁ
⊥
characteristic for a d9 system with an axial symmetry type of dx
2
2
−y
ground state. The g values for the copper(II) complexes denote
to octahedral geometries around copper(II) ions [31]. The trend
g > g > ge (2.0023) shows that the unpaired electron is localized in
ꢁ
⊥
the dx
orbital [32,33]. In addition exchange coupling interaction
2
2
−y
between two copper(II) ions explained by Hathaway expression
G = (g − 2)/(g − 2). If G > 4.0, the exchange interaction is negligible
ꢁ
which is typically the case for complex 8 (G = 4.2). Kivelson and
Neiman noted that for an ionic environment, g is normally 2.3 or
ꢁ
Fig. 6. The electronic spectrum of complex (3).
larger but for covalent environment, g is less than 2.3. The g value
ꢁ
ꢁ
for copper(II) complexes was larger than 2.3 (2.379) consequently
the environment is essentially ionic [32,33].
3.3. Thermal analysis
The TG–DTA results for some solid complexes 4–9 are depicted
in Table 4. The results are in good agreement with the formulae
shown in Fig. 2.
Table 4 concludes that there is a general decomposition pat-
tern, whereby, the complexes decompose in three main stages. The
first stage for all studied complexes is the loss of hydrated water
molecules at 32–150 ◦C, followed in a second decomposition stage
by the loss of the coordinated water, chloride, nitrate or acetate
ions at 70–420 ◦C, after that, the deligation process started at a tem-
perature range of 180–1000 ◦C, finally metal oxide formation takes
place.
Fig. 7. The electronic spectrum of complex (6).
broad band at 800–708 and a shoulder at 626–605 nm, assigned
3.4. Antibacterial activity
to 2B1 → E and 2B1 → B2 transitions, respectively, indicating a
distorted tetragonal structure [27,28]. The electronic spectrum
of copper(II) complex 10 shows a broad structured bands at
584–568 nm which suggesting a square planar geometry around
the copper(II) ion [29].
2
2
The antibacterial activities of the ligand and its metal complexes
were screened using the disk diffusion method [33,34]. The varia-
tion in the effectiveness of different compounds against different
organisms depends either on the impermeability of the cell of the
Table 4
TGA and DTA data for some metal complexes.
No.
Complex
Temperature range
in TGA (◦C)
Weight loss found
(calcd.) (%)
DTA peaks
Disassociation assignment
4
40–70
150–180
180–630
0.7(1.0)
9.1(8.4)
–
51 ◦C
Loss of 0.25 mole of hydrated water
Loss of 2 mole of coordinated water
Deligation
[Co(L)(OAc)(H2O)2](1/4)H2O
170 ◦C
284, 336, 488, 550 ◦C
5
50–90
90–170
170–270
270–800
3.2(3.9)
7.5(7.9)
15.5(14.3)
–
70 ◦
C
C
Loss of 1 mole of hydrated water
Loss of 2 mole of coordinated water
Loss of two coordinated chloride ions.
Deligation
[Ni(HL)Cl2(H2O2)]·H2O
150 ◦
240 ◦C
–
6
7
35–85
85
9.9(9.9)
–
40 ◦C
Loss of 3 mole of hydrated water
Start of deligation
[Ni(HL)(NO3)2(H2O)2]·3H2O
[Ni(HL)(OAc)2(H2O)]·H2O
132, 414 ◦
C
32–70
70–171
173–361
361–520
4.1(3.7)
3.9(3.7)
23.9(24.3)
–
150 ◦
150 ◦
C
C
Loss of 1 mole of hydrated water
Loss of 1 mole of coordinated water
Loss of two coordinated acetate groups
Deligation
210 ◦C
8
9
40–95
3.2(3.9)
8.5(7–8)
14.9(15.4)
–
55 ◦
C
Loss of 1 mole of hydrated water
Loss of 2 mole of coordinated water
Loss of two coordinated chloride ions
Complete deligation
[Cu(HL)Cl2(H2O)2]·H2O
[Cu(HL)2(NO3)2]·5H2O
165–205
205–420
420–100
–
45–150
150–210
210–500
6.0(6.6)
5.0(4.4)
–
77 ◦
C
Loss of 3 mole of hydrated water
Loss of 2 mole of coordinated water
Complete deligation
200 ◦C
321, 350,416,444

S.M. Emam et al. / Spectrochimica Acta Part A 72 (2009) 291–297
297
Table 5
Antimicrobial activities of HL ligand and its metal complexes.
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Hansen, II Farmaco 58 (2003) 1179–1186.
No. Compound
Diameter of inhibition zone (mm)
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[14] M.G. El-Meligy, S.E. El-Rafie, K.M. Abu-Zied, Desalination 173 (2005) 33–44.
[15] T.B. Chaston, D.R. Richardson, Am. J. Hematol. 73 (2003) 200–210.
[16] P.V. Bernhardt, P. Chin, P.C. Sharpe, J.-Y.C. Wang, D.R. Richardson, J. Biol. Inorg.
Chem. 10 (2005) 761–777.
[17] M. Bakir, I. Hassan, J. Johnson, O. Brown, O. Green, C. Gyles, M.D. Coley, J. Mol.
Struct. 688 (2004) 213–222.
[18] X. Ge, I. Wender, P. Schramel, A. Kettrup, React. Funct. Polymer 61 (2004) 1–10.
[19] J. Bassett, R.C. Denney, G.H. Jeffery, J. Mendham, Vogel’s Textbook of Quan-
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edition, Longman Group, London, 1978, pp. 316–322.
Fusarium
Oxysporum
Esherichia coli B. Cereus Candida
1
8
10
11
12
HL
NDa
ND
ND
ND
ND
ND
ND
ND
3.0
2.3
3.9
ND
ND
ND
ND
ND
[Cu(HL)Cl2(H2O)2]·H2O ND
[Cu(L)(OAc)(H2O)]·H2O ND
[Zn(HL)2(NO3)2]·H2O
ND
ND
[Hf(HL)Cl4]
a
ND: non-detected.
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447–453.
[27] E.W. Ainscough, A.M. Brodie, A.J. Dobbs, J.D. Ranford, J.M. Water, Inorg. Chim.
Acta 267 (1998) 27–38.
[28] G. Ertem, D.X. West, J.P. Scovill, Trans. Met. Chem. 10 (1985) 131–134.
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Publishing Company, Amsterdam, 1984.
[30] K.B. Gudasi, S.A. Patil, R.S. Vadavi, R.V. Shenoy, Trans. Met. Chem. 31 (2006)
586–592.
[31] A.S. El-Tabl, Trans. Met. Chem. 27 (2002) 166–170.
[32] S. Chandra, L.K. Gupta, Spectrochim. Acta Part A 60 (2004) 2411–2417.
[33] S. Chandra, L.K. Gupta, Spectrochim. Acta Part A 62 (2005) 1102–1106.
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microbes or difference in ribosome’s of microbial cells [35–37]. The
in vitro antimicrobial activity of the synthesized compounds was
assayed on bacteria. All compounds showed a good antibacterial
activity against Gram negative bacteria (Bacillus cereus) and do not
show any effect on bacteria (E. coli, Candida and Fusarium oxyspo-
rum). Complex 12 proved to be the most effective one (Table 5).
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