Preparation, characterization and biological activity of new tridentate imine-oxime ligand (H2L) and Its metal complexes

Article abstract of DOI:10.14233/ajchem.2018.21257

The new tridentate Schiff-oxime ligand 1-[2-(2,4-dihydroxybenzylidene)aminophenyl]ethanone oxime (H2L), prepared via condensation of equal amounts of 1-(2-aminophenyl)ethanone oxime and 4-hydroxysalicylaldehyde. H2L ligand characterized by using FTIR, UV-

Full text of DOI:10.14233/ajchem.2018.21257

Asian Journal of Chemistry; Vol. 30, No. 5 (2018), 1157-1164
A
SIAN
J
OURNAL OF HEMISTRY
C
https://doi.org/10.14233/ajchem.2018.21257
Preparation, Characterization and Biological Activity of New
Tridentate Imine-Oxime Ligand (H L) and Its Metal Complexes
2
1,*
1
2
1
BASIM H. AL-ZAIDI , AHMED H. ISMAIL , ALI N. NASEAF and WESSAL KHAMIS
1
2
Department of Chemistry, College of Science, Al-Mustansiriyah University, Baghdad, Iraq
Department of Chemistry, College of Education Ibn al-Haytham, University of Bahgdad, Baghdad, Iraq
*Corresponding author: E-mail: basimhatim@uomustansiriyah.edu.iq
Received: 30 January 2018; Accepted: 27 February 2018;
Published online: 29 March 2018;
AJC-18858
The new tridentate Schiff-oxime ligand 1-[2-(2,4-dihydroxybenzylidene)aminophenyl]ethanone oxime (H
2
L), prepared via condensation
of equal amounts of 1-(2-aminophenyl)ethanone oxime and 4-hydroxysalicylaldehyde. H L ligand characterized by using FTIR, UV-
2
1
13
3+
2+
2+
2+
2+
visible spectroscopies, H NMR, C NMR spectra and Mass spectrum. Metal ions complexes with Cr , Mn , Co , Ni and Cu ions,
prepared in a M:L (1:2) ratio and characterized by IR, UV-visible spectroscopies, magnetic susceptibility, molar conductivity and flame
atomic absorption measurements. Results of spectral studies proved the chelation behaviour of this ligand, which coordinated to metal
ions as a monobasic NNO tridentate ligand, via imine and oxime nitrogen atoms in addition to phenolic oxygen atom, after losing its
proton. The proposed geometry of all the prepared complexes was octahedral. The minimal inhibition zone against two Gram-positive
(
Staphylococcus aureus and Staphylococcus epidermidis) and two Gram-negative bacteria (E. coli and Klebsella spp.) also determined.
Keywords: NNO tridentate, Schiff-oxime, Metal complexes, o-Aminoacetophenone oxime, 4-Hydroxy-salicylaldehyde,Antibacterial activity.
Auto magnetic susceptibility balance (Sherwood Scientific)
at 300 K has been used to measure magnetic susceptibility of
prepared complexes. Inolab Multi 740, WTW 82362Weilhiem-
Germany at 25 °C has been used to record conductivity measu-
INTRODUCTION
Schiff-oxime ligands characterized by the existence and
participation of iminic- and oximic azomethine groups in
coordination with metal ions [1-3]. Metal complexes of imine-
oxime have various applications in different scientific fields.
It has been used as antimicrobial [4], antibacterial [5], anti-
fungal [5,6] as well as anticancer [7]. Some of Schiff oxime
derivatives have been used in extraction [8] and spectrophoto-
metric determination [9] of metal ions. Imine-oxime complexes
have been also found used as catalysts for selective oxidation
of alcohols to ketones and aldehydes [10].
-3
rements of complexes solutions in DMSO solvent (10 M).
Synthesis of [1-(2-aminophenyl)ethanone oxime] (o-
AOX) [11]: 10 mL Absolute ethanolic solution of o-amino-
acetophenone (o-ACP, 1.352 g, 0.01 mol) gradually added to
a mixed solvent solution EtOH/H
(
(
2
O, (35/15) mL contains
1.042 g, 0.015 mol) of hydroxylamine hydrochloride and
1.23 g, 0.015 mol) of sodium acetate. Final reaction mixture
reflux for 7 h. The white needle precipitate washed with distilled
water, then dried and recrystallized from hot absolute ethanol.
Synthesis of 1-[2-(2,4-dihydroxybenzylidene)amino-
EXPERIMENTAL
Chemicals have been procured from Fluka and Sigma-
Aldrich. Shimadzu (FT-IR), 4800S spectrophotometer has
been used to get FTIR spectra of prepared compounds (4000-
phenyl]ethanone oxime (H L): The solution of precursor
2
o-AOX, (1.5 g, 0.01 mol) in 15 mL of hot absolute ethanol
gradually added to solution of 4-hydroxysalicylaldehyde
(2.01 g, 0.01 mol) in 15 mL of hot ethanolic solution. Although
yellow precipitate formed after 3 h, 1 h has been added to
period of reflux. The reaction mixture kept in refrigerator
overnight. Next day the product filtered off, washed with
diethylether and cold absolute ethanol, respectively. The purity
of product tested with TLC technique by using 7:3 mL ratio
of (hexane:ethyl acetate). Scheme-I represents the preparation
-1
4
00 cm , KBr). Cary 100con. spectrophotometer has been used
for electronic spectra of prepared compounds at wavelength
00-800 nm. Stuart digital SMP30 apparatus used for measu-
ring melting points of compounds. Mass spectrum of H L was
performed on GC-MS QP-2010 (Shimadzu). NMR spectra of
L in DMSO-d were recorded by Bruker DMX-500 spec-
2
2
H
2
6
trophotometer (300 MHz). Phoenix-986 AA spectrophoto-
meter has been used to estimate the metal ions percentages.
reaction of H L.
2

1
158 Al-Zaidi et al.
Asian J. Chem.
HO
O
HO
HO
N
Ethanol
N
NH2
OH
H C
3
Refluxed 4 h
-
H O
2
HO
N
H3C
OH
)-1-(2-((E)-(2,4-
Dihydroxybenzylidene)amino)phenyl)
(E
4
-Hydroxy
o
-AOX
salicylaldehyde
ethanone oxide (H L)
2
Scheme-I: Synthesis of 1-(2-(2,4dihydroxybenzylidene)amino)phenyl)ethanone oxime (H L)
2
Synthesis of metal complexes: One similar method has
been followed to synthesis of all metal ion complexes. Metal
chloride salt (0.0005 mol) dissolved in 5 mL of absolute ethanol
TABLE-2
C NMR DATA AND CHEMICAL SHIFTS ASSIGNMENT OF H L
13
2
12
6
13
5
7
11
1
and slowly added to H L (0.270 g, 0.001 mol) dissolved in 15 mL
2
8
N
4
OH
hot absolute ethanol. At mixing time colour change has been
noticed at reaction mixture.All obtained solutions then heated
under reflux for 4 h. All the complexes precipitate collected
after slow evaporation of their solutions at room temperature.
The precipitates washed repeatedly with diethyl ether then
distilled water. Finally all coloured precipitates recrystallized
by hot absolute ethanol solution.
10
2
9
3
14
HO
N
15
O
δ (ppm)
59.20, 156.86
40.93
Assignment
1
(C2-OH), (C4-OH)
CH=N (C7)
1
7
4,23
-CH- (C14)
RESULTS AND DISCUSSION
11.88
CH (C15)
3
1
13
140.64, 131.30
C8, C9
C6, C10
C12, C11
C13, C1
C5, C3
H NMR and C NMR spectra of H L: The chemical
2
1
1
27.47, 125.38
18.25, 116.20
shifts data and their assignments of both NMR spectra were
listed, respectively (Tables 1 and 2).
114.77, 113.83
105.85, 103.75
1
H NMR spectrum of H L exhibited signals at (δ = 11.62
2
ppm, 6.19 s, 2H), (δ = 9.39 ppm, s, 1H), (δ = 7.61 ppm, d, 1H)
and (δ = 2.33 ppm, 3H), which were assigned respectively to
phenolic [12] hydroxyl groups (2-OH and 4-OH), oxime [13]
1
3
The C NMR spectrum of H L exhibited chemical shifts
2
at (δ = 159.20, 156.86 ppm), (δ = 140.93 ppm) and (δ = 11.88
hydroxyl group, azomethine (CH=N) [13] and CH
3
group
ppm), which are assigned to C2-OH, C4-OH [11,12], (C=N)
of azomethine carbon (C7) and sp hybridized carbon atom
3
[6,13] protons, respectively. The signals were observed at (δ =
7.34 ppm, d, 1H), (δ = 7.25 ppm, t, 1H), (δ = 6.98 ppm, d, 1H),
related to CH group [11,13], respectively. The spectrum also
3
(
1
δ = 6.85 ppm, d, 1H), (δ = 6.78 ppm, t, 1H), (δ = 6.25 ppm, s,
H) and (δ = 6.11 ppm, d, 1H), assigned to H , H , H , H
revealed new chemical shift at δ = 74.23 ppm due to oxime-
nitroso tautomer [14].
1
2
7
6
,
H
3
,H
5
and H
4
, respectively.
Mass spectrum of H
ion peak of H L at m/z = 270, related to M . The proposal
pathways of H L fragmentation are described in Scheme-II.
Characterization of metal ion complexes: The yield per-
2
L: Fig. 1 clearly reveals the mother
+
2
TABLE-1
2
1
H NMR DATA CHEMICAL SHIFTS ASSIGNMENT OF H L
2
H3
H5
H4
centages, physical properties and metal content of H
metal complexes are tabulated in Table-3.
2
L and its
H6
H2
FTIR study: The FTIR spectrum of H L (Fig. 2) exhibited
2
-1
-1
N
two strong and sharp bands at 3369 cm and 3308 cm , related
to ν(O-H), of phenolic hydroxyl group (4-OH) [15] and oxime
hydroxyl group [11], respectively. These two bands disappea-
OH
H1
HO
H7
N
red in complexes spectra. Except C
2
complex, because it over-
H3C
lapped with each other inside broad band observed at range
OH
-1
3
400-3100 cm , as shown in FTIR spectrum of C
3
complex
δ (ppm)
Assignment
(
Fig. 3). The ν(O-H) of phenolic hydroxyl group (2-OH) in
1
6
1.62 (1H, s)
.19 (1H, s)
2-OH
4-OH
(oxime) (OH)
-1
ligand spectrum observed as broad band at 3174 cm , because
its involvement in hydrogen bonding (intra-ligand hydrogen
bond) with nitrogen atom of azomethine linkage (O–H···N)
[16]. The latter band disappeared [15,16] in complexes spectra,
this proved the involvement of it in coordination with metal
ions. The phenolic ν(C–O) stretching vibration which observed
9.39 (1H, s)
7
.61 (1H, s) 2.33 (3H, s)
(CH=N, CH ) (H)
3
7
6
.34, 6.11 (2H, d)
.98, 6.85 (2H, d)
H , H
1
4
H , H
7
6
7
.25, 6.78 (2H, t)
H , H
2
3
6.25 (1H, s)
H5

Vol. 30, No. 5 (2018)
Preparation and Biological Activity of New Tridentate Imine-Oxime Ligand (H L) and Its Metal Complexes 1159
2
110
160
100
75
50
25
0
1
33
3
9
65
77
116
253
254
270
9
2
143
5
1
1
83
240
1
68
195
211
225
5
0.0
75.0
100.0
125.0
150.0
175.0
200.0
225.0
250.0
Fig. 1 Mass spectrum of 1-(2-(2,4dihydroxybenzylidene)amino)phenyl)ethanone oxime (H L)
2
N
OH
-
OH
N
CH3
OH
N
OH
N
CH
3
OH
m/z=110 (100%)
m/z=253 (24%)
HC N
O
N
CH3
m/z=160 (100%)
3
m/z=270 (22%)
N
C
3
H
C
-
N
m/z=82 (21%)
7
1
O
-
N
O
m/z=211 (2%)
CH3
OH
N
m/z=225 (2%)
N
N
O
C
CH3
-
C
m/z=133 (52%)
m/z=195 (1%)195.22
m/z=51 (15%)
-
O
-
1
6
N
N
O
O
m/z=183 (5%)
3HC
m/z=117 (8%)
O
m/ z=168 (2%)
m/z=92 (23%)
m/z=183 (5%)
C
N
N
m/z=64 (17%)
O
C
O
m/z=150 (68%)
m/z=102 (11%)
m/z=106 (13%)
-
26 -CN
m/ z=168 (2%)
+2
+2H
-
1
m/z=76 (11%)
m/z=82 (22%)
m/z=76 (11%)
Scheme-II: Proposal Pathways of H L fragmentation
2
TABLE-3
YIELD PERCENTAGES, PHYSICAL PROPERTIES AND METAL CONTENT OF COMPOUNDS
-1
Comp.
m.f.
m.w. (g mol )
270.28
Colour
Yellow
Light brown
Dark brown
Yellowish brown
Greenish brown
Olive
m.p. (°C)
188-190
214-216
182-184
298-300
225-228
181-183
Yield (%)
M (%): Calc. (found)
–
H L
C H N O
3
93
43
41
47
54
57
2
15 14
2
C1
C2
C
3
C4
C5
C H N O CrCl
626.00
593.49
597.48
597.24
8.31 (7.80)
9.26 (8.76)
9.86 (10.16)
9.83 (9.32)
10.55 (11.87)
30
26
4
6
C H N O Mn
30
26
4
6
C
30
H
26
N O
4 6
Co
C H N O Ni
30
26
4
6
C H N O Cu
602.10
30
26
4
6

1
160 Al-Zaidi et al.
Asian J. Chem.
–
1
-1
-1
in the spectrum of H
2
L at 1257 cm , has been shifted by 2-13
ranges 563-543 cm and 466-462 cm attributed to (M–O)
and (M–N) vibrations, respectively [6]. Characteristic bands
of prepared compounds with their frequencies and assignments
are listed in Table-4.
–1
cm to lower frequencies [16] in complexes spectra. This also
indicated the participation of phenolic oxygen atom in coordi-
nation with metal ions. The azomethine groups of Schiff and
-1
-1
oxime noticed at 1624 cm and 1600 cm in H
2
L, turned into
Absorption spectra and magnetic properties of comp-
lower frequencies in the complexes spectra [15,16]. This
proved the participation of both groups in coordination with
metal ions. The ν(C–N) and ν(C–O) vibrations suffered from
significant changes as a result of coordination. New vibration
bands have been noticed in complexes spectra at wavenumber
lexes: Spectral data and the magnetic moment of H
metal complexes are tabulated in Table-5. Fig. 4 represents
the absorption spectra of H L and its complexes.
The UV-visible spectrum of H L, reveals five absorption
2
L and its
2
2
-1
-1
peaks at (225 nm, 44444 cm ), (240 nm, 41666 cm ), (262
TABLE-4
-
1
FTIR SPECTRAL DATA (cm ) OF H L AND IT’S COMPLEXES
2
ν(C–H)
Arom.
Alph.
ν(C–O)
ν(C–N)
ν(N–O)
ν(C=N) sch.
ν(C=N) ox.
ν(M–O)
ν(M–N)
Comp.
ν(O–H) phenol ν(O–H) oxime
ν(C=C)
1
257 (s)
3
369 (s)
3070 (w)
2976-2901 (w)
1624 (s)
1600 (s)
–
–
H L
2
3308 (s)
1489-1438
1533-1431
1539-1437
1535-1440
1535-1437
1539-1429
1180 (s)
3
174 (br)
1
1
039 (m)
247 (m)
3080 (w)
1608 (s)
1583 (s)
553 (w)
462 (w)
C1
C2
C3
C4
C5
–
–
–
–
–
–
1197 (m)
2
804-2777 (w)
1035 (w)
1
255 (m)
3369 (s)
3086 (w)
2918 (w)
1600 (s)
1539 (w)
545 (w)
466 (w)
1182 (m)
026 (w)
253 (s)
1199 (s)
–
1
1
3
2
064 (w)
914 (w)
1606 (s)
1587 (s)
563 (w)
462 (w)
–
–
–
1035 (w)
1244 (w)
1612 (s)
553 (w)
466 (w)
–
1193 (s)
1
570 (m)
1012 (w)
1
249 (m)
3084 (w)
1610 (s)
1579 (m)
543 (w)
462 (w)
1192 (s)
037 (w)
–
1
75
60
45
30
15
0
4000
3600
3200
2800
2400
2000
1800
1600
1400
1200
1000
800
600
–
1
Wavelength (cm )
Fig. 2. FTIR spectrum of H L
2

Vol. 30, No. 5 (2018)
Preparation and Biological Activity of New Tridentate Imine-Oxime Ligand (H L) and Its Metal Complexes 1161
2
60
45
30
15
0
-15
4000
3600
3200
2800
2400
2000
1800
1600
1
1400
1200
1000
800
600
–
Wavelength (cm )
Fig. 3. FTIR spectrum of C
TABLE-5
3
complex
ABSORPTION DATA OF H L AND PREPARED COMPLEXES
2
Compound symbol
colour in solid state)
Molar
conductance
(S cm mol )
–
1
(
λmax (nm)
25
240
262
296
ν (cm )
Assignment
µeff (BM)
Geometry
2
-1
(colour in EtOH)
2
44444
41666
38167
33783
26666
46511
38022
34013
22988
H L
Yellow)
Yellow)
*
2
π→π
(
(
–
–
–
3
2
2
75
15
63
ILCT
Ligand field
C1
294
(
(
Light Brown)
Light Brown)
4
(F)
4
(P)
3.91
39.4
Oh
Oh
4
5
6
35
59
69
( A g → T g ) (ν ) & CT
2 1 3
4
(F)
4
(F)
17889
14947
( A g → T g ) (ν )
2 1 2
4
(F)
4
(F)
( A g → T g ) (ν ) (10Dq)
2
2
1
2
2
2
3
2
2
2
3
15
36
62
07
14
50
70
25
46511
38022
38167
32573
46728
40000
37037
30769
23474
C2
(
Dark Brown)
Ligand field
Ligand field
5.40
12.12
(
Brown)
C3
(
Yellowish Brown)
Brown)
3.90
8.76
Oh
4
(F)
4
(p)
(
426
( T g → T g ) (ν ) & CT
1 1 3
4
(F)
4
(F)
6
9
70
46
14925
10373
T g → A g (ν2)
1 2
4
(F)
4
(F)
**
( T g → T g ) (ν )
1
2
1
2
2
2
3
14
29
61
12
46728
43668
38314
32051
Ligand field
C4
Greenish Brown)
Brown)
(
2.85
1.79
8.55
Oh
Oh
3
(F)
3
(p)
(
395
25316
A g → T g ) (ν ) & CT
2 1 3
3
(F)
3
(F)
5
6
88
67
17006
14992
A g → T g ) (ν )
2 1 2
3
(F)
3
(F)
A g → T g ) (ν )
2
2
1
2
2
2
3
3
6
14
48
95
30
92
20
46728
40322
33898
30303
25510
16129
C5
Olive)
Light green)
Ligand field
(
12.80
(
CT
Eg→ T g
2
2
2
**Calculated theoretically.

1
162 Al-Zaidi et al.
Asian J. Chem.
1
1
0
.500
.125
.750
1
1
0
0
.500
.125
.750
.375
0
.250
H2L
C1
0.188
0
0
.125
.063
0.375
0
0
3
80
500
600
700
800
Wavelength (nm)
0
2
00
400
600
800
200
400
600
800
Wavelength (nm)
Wavelength (nm)
1
1
0
0
.750
.313
.875
.438
0
1
1
0
.500
.125
.750
0
.200
C2
C
3
0.150
0
0
.100
.050
0.375
0
0
6
00
650
700
750
800
Wavelength (nm)
200
400
600
800
200
400
600
800
Wavelength (nm)
Wavelength (nm)
1
.200
.900
.600
.300
1
0
0
.000
0
.500
C4
0.500
0.375
C5
0
0
0
0.375
.750
.500
0
0
.250
.125
0
0
0
.250
.125
0
500
600
700
800
0.250
0
Wavelength (nm)
500
600
700
800
Wavelength (nm)
0
2
00
400
600
800
200
400
600
800
Wavelength (nm)
Wavelength (nm)
Fig. 4. Absorption spectra of H L and its metal complexes
2
-
1
-1
nm, 38167 cm ), (296 nm, 33783 cm ) and (375 nm, 26666
was 3.91 BM within the normal range of octahedral geometry
[21,23].
-
1
*
cm ). The first three absorption peaks assigned to π→π
transitions of benzene rings and oxime azomethine group
17,18], the fourth absorption peak assigned to π→π transition
The ILCT transition of free ligand absent in spectrum of
*
2+
[
Mn (C
2
) complex, as a result of involvement the non-bonding
of Schiff azomethine group [17,19]. The fifth low intensity
absorption peak assigned to intra-ligand charge transfer transi-
tions (ILCT) [20].
lone pairs of azomethine groups nitrogen atoms in coordination
with Mn(II) ion [23]. The spectrum also exhibited four
-1
absorption peaks at (215 nm, 46511 cm ), (236 nm, 38022
3+
-1
-1
-1
Spectrum of Cr (C
peaks [21] at (669 nm, 14947 cm ), (559 nm, 17889 cm )
1
) complex, exhibits three absorption
cm ), (262, 38167 cm ), (307 nm, 32573 cm ), related to
ligand field spectra [21]. Any d→d peak might be assigned to
the manganese(II) center was not observed [24]. The room
temperature magnetic value was 5.4 BM, which confirm the
-1
-1
-
1
and (435 nm, 22988 cm ). First two them assigned to
4
(F)
4
(F)
4
(F)
4
(F)
(
[
(
A
2
g → T
2
g ) (ν
1
) (10Dq) [20] and ( A
2
g → T
1
g ) (ν )
2
21], transitions, respectively. The third peak assigned to
presence of octahedral high spin Mn(II) complex [21].
4
(F)
4
(P)
2+
A
2
g → T
1
g ) (ν
3
) and charge transfer (CT) transitions. The
Ultraviolet region of Co (C
3
) complex, exhibits four peaks
-1
-1
spectrum also exhibits other three peaks at (215 nm, 46511
(214 nm, 46728 cm ), (250 nm , 40000 cm ), (270 nm, 37037
-1
-1
-1
-1
-1
cm ), (263 nm, 38022 cm ) and (294 nm, 34013 cm ), respec-
tively, were ascribed to ligand field spectra [21]. The value of
cm ) and (325 nm, 30769 cm ) which which assigned to ligand
field spectra [21]. The spectrum also shows new low intensity
-1
4
(F)
4
(p)
1
0 Dq is equal to energy of first transition [22]. The Racah
peak at (426 nm, 23474 cm ), attributed to ( T
(ν ) and MLCT transition [25,26]. At high concentration [26]
another new peak has been noticed at (670 nm, 14925 cm ),
1
g → T
1
g )
parameter (β), (B′) and (% Covalency) have been calculated
3
-1
depending upon Tanabe-Sugano diagram and the values were
-1
4
(F)
4
(F)
0
(
.39, 354 cm and 61 %, respectively. The value of Racah
β), indicated the existence of covalence character in bonding
between H L and Cr(III). The value of effective magnetic moment
assigned to T
1
g → A
2
g (ν
2
), transition. The Racah parameter
(β), (B′) and (% Covalency) obtained from Tanabe-Sugano
-1
2
diagram and their values were 0.46, 451 cm and 54 %, respec-

Vol. 30, No. 5 (2018)
Preparation and Biological Activity of New Tridentate Imine-Oxime Ligand (H L) and Its Metal Complexes 1163
2
tively. Moderate covalence character in bonding between
Co(II) and H L has been proved from β value. This confirm in
addition to value of magnetic moment (5.4 BM), the existence
of Co(II) ion in an octahedral geometry [25].
TABLE-6
INHIBITION ZONE (mm) DATA OF PREPARED
COMPOUNDS AGAINST SELECTED BACTERIA
2
Gram-positive bacteria
Gram-negative bacteria
2
+
Compd.
S.
aureus
S.
E.
Klebsella
Absorption spectrum of Ni (C
4
) complex revealed four
epidermidis
coli
spp
-1
absorption peak at ultraviolet region (214 nm, 46728 cm ),
229 nm, 43668 cm ), (261 nm, 38314 cm ), (312 nm, 32051
cm ), were assigned to ligand field spectra [21]. This spectrum
exhibited three peaks at visible region (395 nm, 25316 cm ),
(
DMSO) (C)
0
0
11
12
0
0
0
12
13
0
0
15
14
8
0
0
12
14
0
-1
-1
(
H L (1)
2
-
1
C (2)
1
-1
C (3)
2
-1
-1
(
588 nm, 17006 cm ) and (667 nm, 14992 cm ), related to
C
3
(4)
0
3
(F)
3
(p)
3
(F)
3
(F)
C (5)
0
0
0
0
14
12
0
10
[
A
2
2
g → T
1
g ) (ν
3
) & CT], [ A
), respectively [21]. The Racah parameter
β), (B′) and (% Covalency) obtained from Tanabe-Sugano
diagram and their values were 0.38, 389 cm and 62 %, respec-
tively. Strong covalence character between Ni(II) and H L has
2
g → T
1
g ) (ν
2
)] and
4
3
(F)
3
(F)
C (6)
5
A
g → T
2
g ) (ν
1
(
-
4
-1
The concentration (1 × 10 M), didn’t show activity
-3
toward any one of selected bacteria. At 1 × 10 M, the solution
of H L exhibited higher antibacterial activity than its complexes
against growth of E. coli (–) [30]. The prepared ligand H L,
showed no effect against growth of S. aureus (+), S. epidermidis
(+) and Klebsella spp (–) [31], while the prepared complexes
2
2
been proved from small β value. The obtained value of mag-
netic moment was 2.85 BM, consistent with two unpaired electron
without orbital contribution of Ni(II) octahedral system [25].
2
2
+
Absorption spectrum of Cu (C
5
) complex, displays four
-1
(C
which exhibits moderately to high activity and the zone of
inhibition 8-14 mm (Table-6). The prepared complex C , showed
no effect against growth of selected bacteria. C complex showed
1
and C ) showed positive effect against four organisms
2
absorption peaks at ultraviolet region (214 nm, 46728 cm ),
248 nm, 40322 cm ), (295 nm, 33898 cm ) and (330 nm,
0303 cm ), were attributed to ligand field spectra [21]. Two
-1
-1
(
3
-1
3
4
absorption peaks have been noticed in visible region exactly
-
1
-1
high activity with a zone of inhibition 14 mm against growth
of E. coli (–) but not has effectiveness against other bacteria.
C complex showed high activity with inhibited zone (10-12
mm) against growth of Klebsella spp. (–) and E. coli (–),
respectively but not has effectiveness against S. aureus (+)
and S. epidermidis (+).
at (392 nm, 25510 cm ) and (620 nm, 16129 cm ) attributed
2
2
to charge transfer (CT) and Eg→ T g and transitions [27],
2
5
respectively. Magnetic moment was 1.79 BM, consistent with
one electron of distorted octahedral geometry [21].
Molar conductivity measurements: The molar conduc-
2
-1
tance value of C
1
complex in EtOH (39.4 S cm mol ) reveals
electrolyte nature [28] (1:1) ratio. Molar conductivity of (C
2
-1
-
Conclusion
2
5
C ) in EtOH solution were within the range (8-13 S cm mol ),
3+
2+
2+
2+
New chelation complexes of Cr , Mn , Co , Ni and
these proved the non-electrolyte nature [29] of these comp-
lexes. Depending upon all previous results we can proposed
suggested structures for complexes, as shown in Fig. 5.
2+
Cu with a new Schiff-oxime ligand have been prepared in
moderate yields percentages.Analytical and spectroscopic data
showed that the complexes are mononuclear and the Schiff-
oxime ligand acting as a monobasic (NNO) tridentate ligand.
The imine-oxime ligand and its metal complexes exhibited
different inhibition behaviour against selected bacteria.
OH
OH
OH
O
CH
3
OH
N
O
Cr
O
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