Synthesis, Characterization And Biological Activity Of Metal Complexes With Schiff Bases Derived From [4- Antipyrincarboxaldehyde]With [2-Amino-5-(2- Hydroxy-Phenyl)-1,3,4-Thiadiazole]

Abstract

New metal complexes of type M2(HL1)2.4H2O[M=(M = Co(II), Ni (II), and
Cu (II)] were prepared using the ligand (HL1) 4- [5-(2-hydroxy-phenyl) - [1, 3,
4-thiadiazol-2-ylimino methyl]-1,5–dimethyl–2–phenyl-1,2 – dihydro – pyrazol
–3- one. The Schiff bases were condensed from [4 -antipyrincarboxaldehyde]
with [2-amino–5 - (2-hydroxy-phenyl - 1, 3, 4 -thiadiazole] in alcoholic medium.
The prepared complexes were characterized by FTIR Spectroscopy, Electronic
spectroscopy, elemental analysis, magnetic susceptibility measurements,
thermal analysis, 1H-NMR spectra, and mass spectra. The activation
thermodynamic parameters, such as ΔE*, ΔH*, ΔS* and ΔG* are calculated
from the TGA curve using Coats-Redfern method. From the spectral
measurements, structures for the complexes were proposed. Preliminary in
vitro tests for antimicrobial activity show that all prepared compounds display
good activity toward Staphylococcus aureus, Escherishia coli, Pseudononas
aeroginosa and Candida albicans.
Key Words: Schiff base, Microwave synthesis, Thermodynamic

Full text

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
83
Synthesis, Characterization And Biological Activity Of
Metal Complexes With Schiff Bases Derived From [4-
Antipyrincarboxaldehyde] With [2-Amino-5-(2-
Hydroxy-Phenyl)-1,3,4-Thiadiazole]
N. Shalan )1( , S. Hamo(2) and M. Kh. Chebani(3)
Received 14/03/2013 Accepted 28/10/2013
ABSTRACT
New metal complexes of type M2(HL1)2.4H2O[M=(M = Co(II), Ni (II), and
Cu (II)] were prepared using the ligand (HL1) 4- [5-(2-hydroxy-phenyl) - [1, 3,
4-thiadiazol-2-ylimino methyl]-1,5–dimethyl–2–phenyl-1,2 – dihydro – pyrazol
–3- one. The Schiff bases were condensed from [4 -antipyrincarboxaldehyde]
with [2-amino–5 - (2-hydroxy-phenyl - 1, 3, 4 -thiadiazole] in alcoholic medium.
The prepared complexes were characterized by FTIR Spectroscopy, Electronic
spectroscopy, elemental analysis, magnetic susceptibility measurements,
thermal analysis, 1H-NMR spectra, and mass spectra. The activation
thermodynamic parameters, such as ΔE*, ΔH*, ΔS* and ΔG* are calculated
from the TGA curve using Coats-Redfern method. From the spectral
measurements, structures for the complexes were proposed. Preliminary in
vitro tests for antimicrobial activity show that all prepared compounds display
good activity toward Staphylococcus aureus, Escherishia coli, Pseudononas
aeroginosa and Candida albicans.
Key Words: Schiff base, Microwave synthesis, Thermodynamic
Parameters, Biological activity, Antipyrin.
(1) PhD., Student, (2)Superviser, (3) Associated Superviser, Department of Chemistry, Faculty of Sciences,
Damascus University, Syria.

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
84
ﻟﺍ ﺽﻌﺒ ﺕﺍﺩﻘﻌﻤﻟ ﺔﻴﺠﻭﻟﻭﻴﺒ ﺔﻴﻟﺎﻌﻓﻭ ﺔﻴﻔﻴﻁ ﺭﻴﻀﺤﺘ ﻥﺩﺎﻌﻤﺴﺍﺭﺩﻭﻬﺘ ﺎ
ﻊﻤﺃ لﻋﺎﻔﺘ ﻥﻤ ﺔﻘﺘﺸﻤﻟﺍ ﻑﻴﺸ ﺱﺴ4- ﻲﺴﻜﻭﺒﺭﻜ ﻥﻴﺭﻴﺎﺒ ﻲﺘﻨﺍ
ﻊﻤ ﺩﻴﻫﺩﻟﺍ2-ﻭﻨﻴﻤﺃ- 5-)2-لﻴﻨﻓ ﻲﺴﻜﻭﺭﺩﻴﻫ(4,3,1- لﻭﺯﺎﻴﺩﺎﻴﺘ
ﻥﻼﻌﺸ ﺭﺼﺎﻨ
)1(
ﻭ ﻭﻤﺤ ﺢﻤﺎﺴ
)2 (
ﻭ ﺩﻤﺤﻤﻲﻨﺎﺒﻴﺸﻟﺍ ﺩﻟﺎﺨ
)3(
ﻉﺍﺩﻴﻹﺍ ﺦﻴﺭﺎﺘ14/03/2013
ﻲﻓ ﺭﺸﻨﻠﻟ لﺒﻗ28/10/2013
ﹼﻠﻤﻟﺍﺹﺨ
ﺕﺭﻀﺤ ﻉﻭﻨ ﺓﺩﻴﺩﺠ ﺕﺍﺩﻘﻌﻤ M2(HL1)2.4H2O، M ﺙـﻴﺤ[M=(M = Co(II), Ni (II), and Cu (II)] ﺕﻤﺩﺨﹸﺘﺴﺍﻭ ﺔﻁﺒﺘﺭﻤﻟﺍ (HL1) =4-]5-)2-لﻴﻨﻓ ﻲﺴﻜﻭﺭﺩﻴﻫ(- 4,3,1-لﻭﺯﺎﻴﺍﺩﺎﻴﺎﺜ [ -2- لـﻴ ﻥﻴﻤﻴﺍ لﻴﺜﻤ]5,1- لﻴﺜﻤ ﻲﺌﺎﻨﺜ-2-لﻴﻨﻓ-2,1- ﻭﺭﺩﻴﻫ ﻲﺌﺎﻨﺜ لﻭﺯﺍﺭﻴﺎﺒ -3-ﻥﻭﺍ[
4-[5-(2-hydroxy-phenyl)-[1,3,4-thiadiazol-2-ylimino methylen]-1,5-dimethyl-2-
phenyl-1,2-dihydro-pyrazol-3-one لﻋﺎﻔﺘ ﻥﻤ ﺕﺭﻀﺤ ﻲﺘﻟﺍ5-2-ﻭﻨﻴﻤﺃ)2- لﻴﻨﻓ ﻲﺴﻜﻭﺭﺩﻴﻫ(4,3,1- ﻊﻤ لﻭﺯﺎﻴﺍﺩﻭﻴﺎﺜ4- ﻥﻴﺭﻴﺎـﺒ ﻲـﺘﻨﺍ ﻲﻘﻨﻟﺍ لﻭﺤﻜﻟﺍ ﻲﻓ ﺩﻴﻫﺩﻟﺍ ﻲﺴﻜﻭﺒﺭﻜ . ﻑﺎـﻴﻁﻷﺍﻭ ﺀﺍﺭﻤﺤﻟﺍ ﺕﺤﺘ ﻑﺎﻴﻁﻷﺍ ﺔﻴﻨﻘﺘﺒ ﺓﺭﻀﺤﻤﻟﺍ ﺕﺍﺩﻘﻌﻤﻟﺍ ﺕﺼﺨﺸ ﺔﻴﻨﻭﺭﺘﻜﻟﻹﺍ ﻥﻴﻨﻁﻟﺍﻭ ﺔﻠﺘﻜﻟﺍ ﻑﻴﻁﻭﻱﺭﺍﺭﺤﻟﺍ لﻴﻠﺤﺘﻟﺍﻭ ﻲﻨﻭﺘﻭﺭﺒﻟﺍ ﻲﺴﻴﻁﻨﻐﻤﻟﺍ ﻱﻭﻭﻨﻟﺍ، ﺕﺩﺩـﺤ ﺎﻤﻜ ﺕـﺒﺍﻭﺜﻟﺍ ﺔﻴﻜﻴﻤﺎﻨﻴﺩﻭﻤﺭﺜﻟﺍΔE*, ΔH*, ΔS* ΔG* ﺔـﻟﺩﺎﻌﻤ ﺩﺎﻤﺘﻋﺎﺒ Coats-Red fern لـﻠﺤﺘﻟﺍ ﻑﺎـﻴﻁﺃ ﻥـﻤ ﻱﺭﺍﺭﺤﻟﺍﺍ لﻠﺤﺘﻟﺍ لﺤﺍﺭﻤ ﻥﻤ ﺔﻠﺤﺭﻤ لﻜﻟﻭ ﺕﺎﺒﻜﺭﻤﻠﻟ ﻲﻨﺯﻭﻟ . ﻙﻟﺫﻜﻭﺕﺴﻴِﻗ ﺔﻴﺴـﻴﻁﺎﻨﻐﻤﻟﺍ ﺔﻴﺴﺎﺴـﺤﻟﺍ . ﺎـﻤﻜ ﻱﺭﺼﻨﻌﻟﺍ لﻴﻠﺤﺘﻟﺍ ﻡﺩﺨﺘﺴﺍ ،ﺹﻴﺨﺸﺘﻟﺍ ﺔﻴﻠﻤﻋ ﻲﻓ ﺓﺩﻋﺎﺴﻤﻠﻟ ﺡﺭﹸﺘﻗِﺍ ﹾﺫﺇ ﺕﺍﺩـﻘﻌﻤﻠﻟ ﺔﻴـﺴﺎﺴﻷﺍ ﺔـﻴﻨﺒﻟﺍ لﻜﺸ . ﺕﺴﻴﻗ ﻲـﻓ ﺎـﻬﻴﻠﻋ لﻭﺼـﺤﻟﺍ ﻡﺘ ﻲﺘﻟﺍ ﻙﻠﺘ ﻊﻤ ﺔﻘﺒﺎﻁﻤ ﺞﺌﺎﺘﻨ ﺕﻁﻋﺄﻓ لﻭﻠﺤﻤﻟﺍ ﻲﻓ ﺓﺭﻴﻐﺘﻤﻟﺍ ﺔﻴﻟﻭﻤﻟﺍ ﺏﺴﻨﻟﺍ
ﺒﻠﺼﻟﺍ ﺔﻟﺎﺤﻟﺍﺔ ﻑﺎﻴﻁﻻﺍ ﺞﺌﺎﺘﻨ ﻥﻤﻭ ﺡﺭﹸﺘﻗِﺍ ﺓﺭﻀﺤﻤﻟﺍ ﺕﺍﺩﻘﻌﻤﻟﺍ ﺔﻴﻨﺒ لﻜﺸ . ﺔـﻴﺠﻭﻟﻭﻴﺒﻟﺍ ﺔـﻴﻟﺎﻌﻔﻟﺍ ﺕﺴﺭﺩ ﺎﻤﻜ ﺕﺎﺒﻜﺭﻤﻠﻟﺎﻴﺭﺘﻜﺒﻟﺍ ﻥﻤ ﺔﺒﺨﺘﻨﻤ ﻉﺍﻭﻨﺃ ﺩﻀ.
ﺔﻴﺤﺎﺘﻔﻤﻟﺍ ﺕﺎﻤﻠﻜﻟﺍ: ﻑﻴﺸ ﺱﺴﺃ، ﻲـﻔﻴﻭﻭﺭﻜﻴﻤﻟﺍ ﺭﻴﻀﺤﺘﻟﺍ ،ﺃ ﻑﻴـﺸ ﺱـﺴ، ﺙـﺒﺍﻭﺜﻟﺍ
ﻴﻤﺎﻨﻴﺩﻭﻤﺭﺘﻟﺍﻴﻜ ،ﺔﺔﻴﺠﻭﻟﻭﻴﺒﻟﺍ ﺔﻴﻟﺎﻌﻔﻟﺍ.
)
1
(
ﺏﻟﺎﻁﻩﺍﺭﻭﺘﻜﺩ ،
)
2
(
،ﻑﺭﺸﻤﻟﺍ ﺫﺎﺘﺴﻷﺍ
)
3
(
،ﻙﺭﺎﺸﻤﻟﺍ ﻑﺭﺸﻤﻟﺍ ﺫﺎﺘﺴﻷﺍ ﺀﺎﻴﻤﻴﻜﻟﺍ ﻡﺴﻗ، ﻡﻭـﻠﻌﻟﺍ ﺔﻴﻠﻜ ، ﻕﺸـﻤﺩ ﺔـﻌﻤﺎﺠ ،
ﺔﻴﺭﻭﺴ.

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
85
Introduction
Increasing physiological importance of nitrogen and sulphur donor organic
compounds [1]. and active role played by coordination certain metal ions to
them[2], have interesting use in synthesizing and studying structural aspects of
metal complexes with some sulphur and nitrogen donor ligands [3].
The aromatic thiadiazole nucleus is associated with a variety of
pharmacological actions, such as fungicidal, and leishmanicides activities.
These activities are probably due to the presence of the – N=C–S group[4,5].
Pyrazole; thiadiazole and its derivatives form an important class of
organic compounds due to their structural chemistry and biological activities
as analgesic, antipyretics and anti-inflammatory [6]. Even the simplest
pyrazolone derivatives like antipyrine and amidopyrine are widely used as
analgesic medicines [7,8]. Pyrazolones are efficient extractants of metal ions
and they have potential to form different types of coordination compounds
due to tautomeric effect of enol and keto form[9]. Pyrazolones, especially
pyrazolone, display several different coordination modes with respect to
classical â-diketonates[10]. Microwave assisted organic reaction
enhancement (MORE) is nowadays a well established technique for
synthesis of various heterocyclic compounds [11-13]. In addition
pyrazolones can form a variety of Schiff bases and are reported to be
superior reagents in biological, clinical and analytical applications [14-20].
In continuation of our work on the metal complexes of Schiff bases, we
report here the study of some new, Co(II), Ni (II) and Cu (II), complexes of
Schiff bases derived from 4-antipyrincarboxaldehyde and 2-amino-5-(2-
hydroxy-phenyl-1,3,4-thiadiazole. Preparation, characterization and
antibacterial activity of the above metal complexes with this Schiff bases are
reported here. Where, HL1 is a Schiff base of 2-amino-5-(2-hydroxy-phenyl-
1,3,4-thiadiazole with 4-antipyrincarboxaldehyde.
The Thermal analysis
From the TGA curves recorded for the successive steps in the
decomposition process of these ligand and complexes it was possible to
determine the following characteristic thermal parameters for each reaction
step: Initial temperature point of decomposition (Ti): the point at which TG
curve starts deviating from its base line. Final temperature point of
decomposition (Tf): the point at which TG curve returns to its base line. Peak
temperature, i.e. temperature of maximum rate of weight loss: the point
obtained from the intersection of tangents to the peak of TG curve. Mass loss
at the decomposition step (Dm): it is the amount of mass that extends from
the point T
i
up to the reaction end point T
f
on the TG curve, i.e. the
magnitude of the ordinate of a TG curve. The material released at each step
of the decomposition is identified by attributing the mass loss (Dm) at a

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
86
given step to the component of similar weight calculated from the molecular
formula of the investigated complexes, comparing that with literatures of
relevant compounds considering their temperature. This may assist in
identifying the mechanism of reaction in the decomposition steps taking
place in the complexes under study. Activation energy (E) of the
composition step: the integral method used is the Coats-Redfern
equation[21-23]. for reaction order n≠1or n= 2, which when linearised for a
correctly chosen n yields the activation energy from the slop;
………..…..n≠1
…………n=1
ΔS*= 2.303R[Log(Ah/K Tmax)], ΔH*=E-RTmax, ΔG*= ΔH* -Tmax ΔS* where:
α = fraction of weight loss, T = temperature (ºK), n = order of reaction, A or
Z = pre-exponential factor, R = molar gas constant, E = activation energy
and q = heating rate. Order of reaction (n): it is the one for which a plot of
the Coats-Redfern expression gives the best straight line among various trial
values of n that are examined relative to that estimated by the Horovitz-
Metzger method[24,25].
Experimental
All used chemicals were of reagent grade (supplied by either sigma
Aldrich or fluka) and used as supplied. The FTIR spectra in the range (4000-
400) cm-1 cut were recorded as KBr disc on FTIR.4200 Jasco
Spectrophotometer. The Uv-visible spectra were measured in ethanol using
Shimadzu Uv-vis. 160 A-Ultra-violet Spectrophotometer in the range (200-
1000) nm. Magnetic susceptibility measurement for complexes were
obtained at room temperature using (Magnetic Susceptibility Balance)
Jhonson Mattey catalytic systems division. Gallencamp M.F.B600.010 F
melting point apparatus were used to measure the melting point of all the
prepared compounds. Elemental microanalysis was carried out using
CHNOS elemental analyzer model 5500 Carlo-Erba instruments (Italy).
1- Synthesis of [2-amino-5-(2-hydroxy-phenyl-1,3,4-thiadiazole] [HL]
A mixture of benzoic acid (0.1 mol12.2g), thiosemicarbazide (0.1 mol 9.1 g)
and (40ml) of POCl3 was heated gently for 3 hours. After cooling than (250
ml) of water was added then refluxed for 4 hours. The mixture was cooled
filtered and the filtrate neutralized with KOH and recrystalization solvent
ethanol. M.p. yield, C.H.N.S analysis in Table (1).

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
87
2-4-[5-(2-hydoxy - phenyl) - [1, 3, 4 - thiadiazol - 2 - ylimino methyl]
- 1,5-dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one [HL1]
Method(1) A mixture of equimolar amounts (0.09 mol) of appropriate (4-
antipyrincarboxaldehyde) and the (2-amino-5-(2-hydroxy-phenyl-1,3,4-
thiadiazole), in absolute ethanol (15 ml) with (2) drops of glacial acetic acid
was refluxed 3 -hours. The reaction mixture was then allowed to cool at
room temperature, and the precipitate was filtered and dried, recrystallized
from ethanol to give yellow powder.
Method(2): A mixture of equimolar amounts (0.09 mol) of appropriate
(4-antipyrincarboxaldehyde) and the (2-amino-5-(2-hydroxy-phenyl-1,3,4-
thiadiazole), were ground with a mortar, mixed, dried and subjected to
microwave irradiation 700W for (30) minutes, after completion the reaction
the mixture was cooled to room temperature and the obtained solid was
recrystallized twice from absolute ethanol, some of physical data for these
four compounds are listed in table. Yield, C.H.N.S analysis in Table (1).
NN
OC
HN
CH3
N
N
S
HO
C
O
OH +H
NCNH2POCl3
Ar H2N
S
H2O/KOH
N
N
S
H2N
HO
C2H5OHref
HL
HL1
N
N
S
H2N
HO
+N
N
O
C
H
O
CH3
HL
CH3COOH
/
H3C
H3C
(Scheme-1) Synthesis of Schiff base ligand
Preparation of complexes
Method(1) :Addition of ethanol solution of the hydrated metal chloride
Ni(II), Co(II) and Cu(II) to an ethanol solution of (HL1) in 1:1 (ligand :
metal) molar ratios. After stirring for 2 hours with heating 50 0C, crystalline
colored precipitates formed then cooling at room temperature, the resulting
solids were filtered off, washed with distilled water, dried and recrystallized
from ethanol and dried at 50 0C
Method(2) : Addition of ethanol solution of the hydrated metal chloride
Ni(II), Zn(II) and Cu(II) to an ethanol solution of (HL1) in 1:1 (ligand :
metal) molar ratios. The reaction mixture was placed in ultrasonic bath for
30 mints crystalline colored precipitates formed when cooled at room
temperature, the resulting solids were filtered off, washed with distilled
water, dried and recrystallized from ethanol and dried at 50 0C. Yield,
C.H.N.S analysis in (Table-1).

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
88
(Table-1) Analysis data of prepared compounds
% element analysis found(calculated)
Molecular formula
(Color)
Yield%
M N H C S
HL
C8H7N3OS 76 - (49.37)
49.51 (3.65)
3.55 (21.75)
21.69 (16.59)
16.63
HL1
C20H17N5O2S 67 - (61.37) (4.38) (17.89) (8.19)
[Ni2(HL1)24H2O] +4 58 (12.07)
12.03 (14.41)
14.39 (4.35)
4.33 (49.41)
49.44 (6.60)
6.57
[Co2(HL1)24H2O] +4 75 (12.12)
12.15 (14.40)
14.44 (4.35)
4.31 (49.39)
49.42 (6.59)
6.56
[Cu2(HL1)24H2O] +4 79 (12.94)
12.89 (14.26)
14.21 (4.32)
4.31 (48.92)
448.95 (6.53)
6.55
Result and discussion
(Table-2) shows the decomposition point, color and electronic Absorption
bands for ligand and complexes. The bands are classified into three distinct
groups: The intermolecular transitions appear in the region, charge transfer
from ligand to metal, and d-d transitions appear in the visible region show in.
These transitions are assigned in relevant to the structures of complexes, and
also Uv-viss spectrum of compound shown in (Fig-1).
1-[2-amino-5-(2-hydroxy-phenyl-1,3,4-thiadiazole] [HL]
The reaction of thiosemicarbazide with benzoic acid in presence of
phosphorus oxychloride afforded 2 – amino – 5 – phenyl-1, 3, 4 - thiadiazole
(P. Coudert, (1994). The structural assignment of the product was based on
it's melting point and spectral (FT-IR, 1H-NMR and Uv/Vis.) data. Besides
the C.H.N.S. analysis (Table-1). The FT-IR spectrum of compound (HL)
(Fig-2) exhibited significant two band in the range (3396–3283)cm-1 which
could be attributed to asymmetric and symmetric stretching vibrations of
NH2 group band in the (3101) stretching vibrations of (OH). Besides this,
band at about (1626 cm-1) due to cyclic (C=N) stretching is also observed.
Bands at (1518 cm-1) and (1484cm-1) are due to the (N-H) bending and (C-N)
stretching vibrations, respectively (Silverstein, R.M. Bassler, G.C. and
Movril, T.C., 1981).
1H-NMR spectrum of compound (HL) shows the following characteristic
chemical shifts (DMSO-d6, ppm). The five aromatic protons appear at:
(δ 7.40-7.94) were due to aromatic protons. Amino protons (NH2) absorbed
at (δ 3.38). Furthermore, the small peak at (δ 2.5) was due to DMSO.

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
89
(Table-2) Some physical data of electronic spectra for ligand and complexes in
ethanol.
Symbol
Dec.
Point 0C
Cond
uctivity
ohm-
1cm2mol-1
Magnetic
Moment
(B.M) Color
Absorption
Bands
(nm)
Assigned
Transition
295 π → π*
HL 238 - - White-
pink 320 n → π*
250 π → π*
HL1 280 - - Green 370 n → π*
225 π → π*
243 n → π*
320 Charge Transfer
380 4T1g(F) → 4t1g(p)
Co(II)
285 12.34 4.47 Red blue
910 4T1g → 4A2g
235 π → π*
295 n → π*
320 Charge Transfer
633 3A2g → 3t1g(p)
Ni(II)
310 15 2.9 Pale
green
960 3A2g → 3t1g(F)
230 π → π*
295 n → π*
360 Charge Transfer
675 2Eg →2T2g
595 4A2g → 4t1g
Cu(II)
320 11.8 1.84 Dark
Green
655 4A2g(F) → 4t1g(p)
2)4-[5-(2-hydoxy-phenyl)- [1, 3, 4- thiadiazol – 2 - ylimino methyl]-1,5
dimethyl -2-phenyl-1,2-dihydro-pyrazol-3-one [HL1]
The FT-IR spectra (Fig-3), show the disappearance of the two absorption
bands due to (-NH2) stretching of amino thiadiazole [HL] showed all the
suggested bonds for olefinic (C-H), (C=C) aromatic, endocyclic (C=N) and
exocyclic imine group. Stretching vibrations in addition to out of plane
bending of substituted aromatic ring. All the prepared compounds (Schiff
bases) exhibited the stretching band near the region (1213-1253) cm-1 this is
due to (=N-N=C-) cyclic group; 3429 cm-1 (υ OH stretching of alcohol),
1651cm-1 (υ C=N Stretching of imine), 1554 cm-1, 1498 cm-1 (Characteristic
bands of pyrazolone ring) 1432 cm-1, 1267 cm-1 (Characteristic bands of
thiazole ring), 1142 cm-1 (υ C-O Stretching of alcohol).
All the spectral data for other compounds are listed in (Table-3).

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
90
1H-NMR spectrum of compounds [HL1], Fig (4), shows the following
characteristic chemical shift, (CDCl3-D6) ppm. The methyl protons resonate
at [δ= 1.5, 2.4,] (s, 3H, CH3), OH proton rosenate at ,(δ 3.4), five aromatic
ring protons of phenyl and four aromatic ring appeared at (δ 6.9 – 7.6) ppm,
proton C appears at (δ 7.8) Furthermore, the signal at (δ 8.8) attributed to
(CH=N) proton.
(Fig-5)The positive ion mass spectral analysis of (HL1) MS observes at
m/z 392.0 (M+1) (Fig-5), confirms the theoretical molecular weight i.e.
391.11., The series of peaks in the table 2 may be assigned to various
fragments (Scheme-2).
-107
H
N
O
C
N
H3C CH2
NN
SH
OH
C
N
NN
SH
+. M/Z284
M/Z179
M/Z157
-22
-105
(B)
(D)
(C)
N
N
O
C
H
N
3HC CH3
NN
S
O
NN
S
H
N
N
O
C
H
N
H3C CH3
NN
S
OH
+1
M/Z391
(HL1)
OH
H
+.
M/Z392
(A)
Scheme. 2
Infrared spectral analysis of metal complexes
The infrared spectra of the ligands show υO-H (weakly H-bonded) at
3429cm-1. The absence of this band in all the metal complexes indicates the
removal of proton of hydroxyl group of benzene ring during the chelation.
The FT-IR spectra (Fig-6,7) of complexes are further supported by the shift
of C-O frequency from 1342 cm-1 (in ligand) to the higher frequency 1379
cm-1 (in complexes)[26-28]. The sharp intense band at 1651 cm-1 in the
ligands can be assigned to υC=N (azomethine). A downward shift (∆υ = 10-
18 cm-1) in υC=N (azomethine) is observed upon coordination indicating
that the nitrogen of azomethine group is involved in coordination. All the
complexes show broad band in the region (3285-3378) cm-1 which may be
assigned to υ O-H of coordinated water[29-31]. To account for the
octahedral stereochemistry of the metal complexes, the coordination of two
water molecules is expected.
The bands at 476 cm-1 in Co(II) complexes, 498 cm-1 in Ni(II) complexes
and 514cm-1 in Cu(II) complexes may be due to metal-nitrogen stretching
vibration[19,20]. All the metal complexes involved in coordination. In the
free ligand, the band at 1606 cm-1 is assigned to the stretching of C=N
(thiazole ring). on complexation, this band is shifted to a lower frequency
H
3
C
H
3
C

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
91
region. This shift is probably due to the lowering of bond order of the
carbon-nitrogen bond resulted from complexation of the metal to the ligand
through nitrogen in υ C=N compared to its respective ligands. This suggests
that the nitrogen atom of the ring has not participated in the chelation.
However, in water containing chelates, this band is observed as a broad with
structure and this may be due to coupling of the bending mode of
coordinated water molecules with matel[32-35]
.
Table (3) Infrared data of Ligand and its metal complexes (cm-1)
v(M-N)
v (O-H) v (O-H) H2O
ν(M-O)
ν(C-N=N-C)
ν(C=N)
ν(C=O)
Symbol
- 3429 - - 1219-1253 1606 1651(s)
HL1 476(s) - 3292 425(s)
1238-1311 1521 1662(s)
Co(II) 498(s) - 3285 442(s)
1585 1593 1661(s)
Ni(II) 570(s) - 3378 481(s)
1240-1308 1607 1633(s)
Cu(II)
Thermal analysis
To understand thermal decomposition process, Schiff and its metal
complexes were examined by thermo gravimetric analysis in the temperature
range of 35–700 ºC. The obtained thermo analytical results from TGA
curves (Fig-8) for all these compounds are given in (Table-4). The
decomposition was completed at 693 ºC for all the complexes. The data from
the thermo gravimetric analyses indicated that the decomposition of the
complexes and the ligand proceeds in (two – four) steps. The comparison of
ligand and the complexes shows that the complexes. the first step of
decomposition was started at (250 ºC) and completed at 693 ºC for all the
complexes. The final stage of the thermal decomposition of given metal
oxides mixture formed above 598 ºC for the matel[22]. (Fig-9) shows Coats-
Redfern pattern of Ligand and complexes. The thermal data have been
analyzed for thermodynamic parameters by using Coats-Redfern[36,37]
(Table-4).
N
N
O
CH
N
CH3
C
H
3
NN
S
NN
OCH
N
CH3
CH3
N
N
S
M
+2
M
+2
H
2
OOH
2
H
2
O
OH
2
O
O
Scheme the structure of
complex ML :
M=Cu(II),Ni(II) and Co(II)

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
92
(Table-4) Thermodynamic parameters of the ligand and metal complexes
Sample
(step)
T.range
ºC N R2 T
max ºK
Ea
K.J mol-1
Δ H*
KJ mol-1
ZSec-1
x105 Δ S*
J mol-1 K-1
Δ G*
KJ mol-1
L1(1) 37-390
1 0.99
535 13.1101 8.661971
1.4969
-342.153 192.0284
L1(2) 390-598
1 0.99
798.51
-6.0569 -12.6845
5.84 -353.297 269.4266
Co(1) 37-108
1 0.99
388 91.198 88.393 2.8 -84.2368 116.8635
Co(2) 108-295
0.9
0.99
479.08
29.024 25.0477
9.21 -287.826 162.939
Co(3) 395-479
0.9
0.99
675 -8.0246 -13.6271
5.57 -352.282 224.1636
Co(4) 479-700
0.9
0.99
792.94
-9.98489
-16.5663
3.98 -356.422 266.0552
Ni(1) 37-115
0.9
0.99
342 30.5012 27.6626
0.4155
-272.491 120.8546
Ni(2) 115-289
0.9
0.99
473.3 33.2497 29.3213
0.2126
-285.063 164.242
Ni(3) 289-700
0.9
0.99
669.2 12.19515
-10.843 9.05 -348.184 222.1616
Cu(1) 37-216
0.9
0.99
423 16.49479
12.98389
7.68 -326.581 151.1275
Cu(2) 216-389
0.9
1 554 54.214 49.616 0.5357
-255.25 191.025
Cu(3) 389-700
0.9
0.99
726.35
-8.14044
-14.1691
4.91 -353.949 242.9219
Biological Activity
With a view to explore the possibility of obtaining biologically useful
complexes that contain 1,3,4- thiadizole and pyrazolone ring system, such
biological activity prompt us to prepare some new series containing the
above mentioned units. The antimicrobial activity of these compounds was
determined by the agar diffusion method using Staphylococcus aureus,
Escherishia coli, Pseudononas aeroginosa and Cndida albicans[38,39]. In
this method a standard 5mm diameter sterilized filter paper disc impregnated
with the compound (1 mg per 1 ml dimethyl suffoxied) was placed on an
agar plate seeded with the test organism. The plates were incubated for 24
hours at 37 0C. The zone of formed inhibition was measured in mm and are
represented by (+), (+ +) and (+ + +) depending upon the diameter and
clarity, (Table-5).The preliminary screening result reveal that compound
contained thiadizole and pyrazolone complexes exhibits highest antibacterial
activity against Escherishia coli[40,41].
(Table-5) Antibacterial activity of the prepared compounds.
Symbol Staphylococcus
aureus Escherishia coli
Pseudononas
aeroginosa Cndida
albicans
HL1 - + - -
Co(II) - + + + + +
Ni(II) + + + + - +
Cu(II) + + + + + +
Note (-) = no inhibition, (+) = (5-10) mm, (+ +)=(11-20) mm, (+ + +) = more than (20)mm

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
93
Fig(1)Uv-vis of ligand and complexes
Fig(2) Infrared spectra of HL

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
94
Fig(3) Infrared spectra of HL1
-2-1
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
ppm
0.861
1.275
1.571
2.885
3.437
6.974
7.128
7.284
7.375
7.503
7.573
8.811
0.69
45.29
5.58
5.52
1.70
37.87
1.65
1.71
Current Data Parameters
NAME NSh_DU122
EXPNO 1
PROCNO 1
F2 - Acquisition Parameters
Date_ 20120617
Time 10.15
INSTRUM av400
PROBHD 5 mm BBO BB-1H
PULPROG zg30
TD 65536
SOLVENT CDCl3
NS 100
DS 2
SWH 8278.146 Hz
FIDRES 0.126314 Hz
AQ 3.9584243 sec
RG 14596.5
DW 60.400 usec
DE 6.00 usec
TE 0.0 K
D1 1.00000000 sec
MCREST 0.00000000 sec
MCWRK 0.01500000 sec
======== CHANNEL f1 ========
NUC1 1H
P1 14.25 usec
PL1 0.00 dB
SFO1 400.1324710 MHz
F2 - Processing parameters
SI 32768
SF 400.1300000 MHz
WDW EM
SSB 0
LB 0.30 Hz
GB 0
PC 1.00
Sample 1_03-06-2012
Fig(4) 1HNMR spectra of HL1

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
95
Fig(5) Electron impact mass spectrum of HL1
Fig(6) Infrared spectra of Cu complexes

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
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Fig(7) Infrared spectra of Cu complexes
Ni/ML1
ML1
Co/ML1
Cu/ML1
Fig(8) TGAof Ligand and complexes

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
97

Shalan, Hamo, Chebani - Synthesis, Characterization And Biological Activity…
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Fig(9) Coats-Redfern pattern of Ligand and complexes

Damascus University Journal for BASIC SCIENCES Vol. 30, No2, 2014
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