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Synthesis and Biological activity of some complexes of (2-phenyl-4-arylidine imidazole-5-one) with some transition metal ions

Authors:

Abstract

A novel imidazole analogs of hipuric acids was synthesized by using acetic anhydride and acetic acid, then treated with hydrazine hydrate to give 3a-b. anew compounds were characterized by 1 HNMR,FTIR and UV spectroscopyand then were used as ligand and complication with some metals, these derivatives were investigated for their antimicrobial activity and antifungal. The prepared complexes were identified and their structural geometries were suggested by using elemental analysis (A.A), FT-IR and UV-Vis. spectroscopy, as well as magnetic susceptibility and conductivity measurements. Metal to ligand [M:L] ratio was obtained for all complexes in (ethanol) using molar ratio method, which gave comparable results with those obtained for the solid complexes. Copy Right, IJAR, 2013,. All rights reserved. Introduction: The synthesis of 1,3-oxazoles is of considerableinterest due to their various biological activities. Reported damming these activities were: nervous system depression[1], analgesic[2,3], herbicidal[4], muscle relaxant[5],and tranquilizing[6] activities. The imidazole nucleus appears in a number of naturally occurring products like the amino acids, histidine and purines which comprise many of the most important bases in nucleic acids[7]. Imidazole derivatives possess a broad spectrum of pharmacological activities such as anticonvulsant[8] anti-Parkinson[9].. In medicine, drugs based on benzimidazoles and benzimidazole derivatives have been patented, due to their antiviral and antihelmintic activity [10]. In metallurgy, benzimidazole has been used as a corrosion inhibitor[11]. Metal complexes play an important role in many biological systems [12]. It has been observed that metal ions have considerable effect on the antimicrobial activity of antibiotics [13-15]. Similarly metal ions are known for their antitumor activity [16]. Transition-metal ions play a number of critical roles in biology. However, the size and complexity of the metalloproteins which contain them makes it difficult to determine the properties that are responsible for their function [17-19]. Among these novel metal complexes derivatives which show considerable biological activity may represent an interesting approach for designing new antibacterial drugs. This may be due to the dual possibility of both ligands plus metal ion interacting with different steps of the pathogen life cycle [20]. Experimental All chemicals were of highest purity and were used as received. Physical measurements and analysis: Melting point were determined in open capillary tubes on a Gallen Kamp melting point apparatus and were uncorrected. The FT-IR Spectra were recorded by KBr and CsI discs using a perkin-Elmer 1600FT-IR 8300 Shimadzu spectrometer in range of (4000-200)cm-1. 1 HNMR Spectra were recorded on a Varian-Mercury 200 MHZ Spectrometer. Electronic spectra of ligands and their metal complexes wererecorded for their solution in ethanol at 200-1100 nm and obtained using UV-1650 PC Shimadzu spectrophotometer. The measurements were recorded using a concentration of 10-3 M of the complex in chloroform as a solvent. Atomic absorption analytical data were
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
399
Journal homepage: http://www.journalijar.com INTERNATIONAL JOURNAL
OF ADVANCED RESEARCH
RESEARCH ARTICLE
Synthesis and Biological activity of some complexes of (2-phenyl-4-arylidine imidazole-5-
one) with some transition metal ions
Maysoon A.A. Al-Soodani1 , Abdulwahab H. M. Ali,2 *Mohammed F.Al-Marjani 3, and AbdulJabar K. Atia4
1 ,4 Department of Chemistry - Al-Mustansiriya University, Baghdad/ Iraq.
2 Institute of Technology / Baghdad- Iraq.
3 Department of Biology - Al-Mustansiriya University, Baghdad/ Iraq
Manuscript Info Abstract
Manuscript History:
Received: 10 January 2014
Final Accepted: 23 February 2014
Published Online: March 2014
Key words:
1,3-Oxazole, Imidazole, Schiff’s
bases Complexes
*Corresponding Author
Mohammed F.Al-Marjani
A novel imidazole analogs of hipuric acids was synthesized by using acetic
anhydride and acetic acid, then treated with hydrazine hydrate to give 3a-b.
anew compounds were characterized by1HNMR,FTIR and UV
spectroscopyand then were used as ligand and complication with some
metals, these derivatives were investigated for their antimicrobial activity
and antifungal. The prepared complexes were identified and their structural
geometries were suggested by using elemental analysis (A.A), FT-IR and
UV-Vis. spectroscopy, as well as magnetic susceptibility and conductivity
measurements. Metal to ligand [M:L] ratio was obtained for all complexes in
(ethanol) using molar ratio method, which gave comparable results with
those obtained for the solid complexes.
Copy Right, IJAR, 2013,. All rights reserved.
Introduction:
The synthesis of 1,3-oxazoles is of considerableinterest due to their various biological activities. Reported
damming these activities were: nervous system depression[1], analgesic[2,3], herbicidal[4], muscle relaxant[5],and
tranquilizing[6] activities. The imidazole nucleus appears in a number of naturally occurring products like the amino
acids, histidine and purines which comprise many of the most important bases in nucleic acids[7]. Imidazole
derivatives possess a broad spectrum of pharmacological activities such as anticonvulsant[8] anti-Parkinson[9]. . In
medicine, drugs based on benzimidazoles and benzimidazole derivatives have been patented, due to their antiviral
and antihelmintic activity [10]. In metallurgy, benzimidazole has been used as a corrosion inhibitor[11]. Metal
complexes play an important role in many biological systems [12]. It has been observed that metal ions have
considerable effect on the antimicrobial activity of antibiotics [13-15]. Similarly metal ions are known for their
antitumor activity [16]. Transition-metal ions play a number of critical roles in biology. However, the size and
complexity of the metalloproteins which contain them makes it difficult to determine the properties that are
responsible for their function [17-19]. Among these novel metal complexes derivatives which show considerable
biological activity may represent an interesting approach for designing new antibacterial drugs. This may be due to
the dual possibility of both ligands plus metal ion interacting with different steps of the pathogen life cycle [20].
Experimental
All chemicals were of highest purity and were used as received.
Physical measurements and analysis:
Melting point were determined in open capillary tubes on a Gallen Kamp melting point apparatus and were
uncorrected. The FT-IR Spectra were recorded by KBr and CsI discs using a perkin-Elmer 1600FT-IR 8300
Shimadzu spectrometer in range of (4000-200)cm-1. 1HNMR Spectra were recorded on a Varian-Mercury 200 MHZ
Spectrometer. Electronic spectra of ligands and their metal complexes wererecorded for their solution in ethanol at
200-1100 nm and obtained using UV-1650 PC Shimadzu spectrophotometer. The measurements were recorded
using a concentration of 10-3M of the complex in chloroform as a solvent. Atomic absorption analytical data were
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
obtained using AA spectrophotometer phoenix-986. Conductivity measurements were obtained using WTW
conductivity multimeter-740. These measurements were recorded in (DMSO) as a solvent using a concentration of
10-3M of the complex at room temperature. Magnetic susceptibility measurements were obtained at 25°C on the
solid state applying Faraday’s method using Bruler BM6 instrument.
A- Synthesis of[(Phenyl-carbonyl amino]acetic acid (hipuric acid)(1)
To a stirring solution of glycine (0.75 g, 0.01 mol) and sodium hydroxide (10 ml,10% solution), benzoyl
chloride ( 0.01 mol) was added. Then, the reaction mixture was shacked vigorously for 1h. ,a few grams of crushed
ice was added with stirring. After that, the solution was acidified with conc. HCl and the product was collected and
recrystallized from ethanol. (yield 67 %), (m.p, C°)(187-189), ( IR. (KBr) (ν, cm-1) 3280 (NH), 3178 (acid OH),
2983-2821 (C-H alph.) ,1746 (acid C=O),1667 (amide C=O);1HNMR (DMSO-d6) ς (ppm) 4.01 (s, NH), 4.67 ( s,
CO-CH2-NH), 6.84-7.98 (m, Aromatic protons).
B- Synthesis of4-(arylidene)-2-phenyl-1,3-oxazol-5(4H)-one(2a- b)
To a stirring mixture of compound 1 (1.8 g, 0.01 mol) acetic acid (5 ml) acetic anhydride (20 ml),aromatic
aldehyde (0.01 mol) was added. The temperature of reaction was reached to 70 C° for 10 min. , then the mixture was
poured in to crushed ice and stirred for 30 min. the product was collected and recrystallized from ethanol to afforded
the desired compound.
2a. (yield 71 %), (m.p, C°)(143-146), IR. (KBr) (ν, Cm-1) 3070 (C-H ar), 3146 (C-H olifen), 1795 (oxazole C=O),
1646 (oxazole C=N), 1600-1509 (C=CAr), 1245 (C-O) 825 (para substitution); 1HNMR (DMSO-d6) ς(ppm) 8.69 (
s,C=CH-), 6.57 7.88 (m, Aromatic protons).
2b. (yield 63 %), (m.p, C°)(167-169), IR. (KBr) (ν,cm-1) 3055 (C-H ar), 3190 (C-H olifen), 1798 (oxazole C=O),
1640 (oxazole C=N), 1606- 1511 (C=C Ar), 1245 (C-O) 860 (para substitution); 1HNMR (DMSO-d6) ς (ppm) 8.46 (
s, C=CH- ), 6.64 7.95 (m, Aromatic protons).
C- Synthesis of 3-amino-5-(arylidene)-2-phenyl-3,5-dihydro-4H-imidazol-4-one (3a b)
To a mixture of compound (2ab) (0.01 mol) in dry pyridine (5ml) hydrazine hydrate (99%) (10ml) was
added. The reaction mixture was refluxed for 20hs. Then, the mixture was allowed to cool to room temperature and
pyridine was removed. The product was recrystallized from ethanol to afford the desired compound.
3a. (yield 53 %), (m.p, C°)(167-168), IR. (KBr) (ν,cm-1) 3350-3289 (NH2), 3088 (C-H ar), 3215 (C-H olifen), 1637
(imidazole C=O), 1589 - 1527 (C=C Ar), 1232 (C-N) 810 (para substitution); 1HNMR (DMSO-d6) ς(ppm) 8.39
(s,C=CH-), 8.82 (s, NH2), 6.76 8.00 (m, Aromatic protons).
3b. (yield 46 %), (m.p, C°)(200-201), IR. (KBr) (ν,cm-1)3277-3223 (NH2), 3061 (C-H ar), 3222 (C-H olifen), 1712
(imidazole C=O), 1604- 1519 (C=C Ar), 1249 (C-N) 823 (para substitution); 1HNMR (DMSO-d6) ς(ppm) 8.19 (s,
C=CH-), 8.77 (s, NH2), 754 7.91 (m, Aromatic protons).
D- Preparation of hipuric acid complexes of L1 (M1-M5) and L2(F1-F5):
Ethanolic solution of each of the following metal ion salts (1mmol) [PdCl2(Na2PdCl4), CoCl2, NiCl2, LaCl3,
CrCl3, PtCl4]; [CuCl2, CoCl2, NiCl2, LaCl3, CrCl3, FeCl3] were added to an ethanolic solution of (0.3074gm, 1mmol)
of L1 and (0.3433 gm, 1mmol) of L2 with stirring. The mixture was heated under reflux for one hour during this time
a precipitate was formed. The product was isolated by filtration, washed several times with distilled water and hot
ethanol then dried in oven. The physical data of the prepared complexes are shown in table (1)& (2).
E- Study of Complexes Formation in Solution :
Complexes of (L) with metal ions were studied in solution using ethanol as solvents in order to determin
[M:L] ratio in the complex following molar ratio method[21]. Series of solutions were prepared having a constant
concentration 10-3M of the metal ion and (L). the [M:L] ratio was determined from the relationship between the
absorption of the absorbed light and the molar ratio of [M:L]. the results of complexes formation in solution were
listed at table (1).
F- Biological activity
1) Microbial isolates:-
Isolates of Esherichia coli, Pseudomonas aeruginosa and Klebsiella pneumonia[Gram (-ve) bacteria] and
Staphylococcus aureus, Enterococcus faecalis [Gram (+ve) bacteria] were collected from different infections
sources from Central Medicine City hospital in Baghdad, and isolate for Candida albicans. Isolates were identified
according to that reported in [22].
2) Antimicrobial activity of (L1,L2) and their complexes against pathogenic isolates:-
Antimicrobial activity of (L1,L2) and their complexes were screened for their inhibitory activity against
[Gram ve bacteria], [Gram +ve bacteria] isolates and Candida albicans, using agar well diffusion method plates
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
were prepared by spreeding Approximately (105 cFu/ml) culture broth of each indicator isolates on Muller- Hinton
agar surface for bacterial isolates and Saboroud - agar surface for Candida albicans Isolate. The agar plates were left
for about (15 mins) before a septically dispensing. The (50 µL) of each compound into the agar wells already bored
in the agar plates. The plates were then incubated at (37 ºC) for (24hs). Zones of inhibition were measured and
recorded in millimeter diameter.
3) Synergism effect of (L1,L2) and their complexes against bacterial isolates:-
Synergism effect of (L1,L2) and their complexes against Staphylococcus aureus and Esherichia coli were
tested by using agar well diffusion Method
Results and discussion
A-Elemental Analysis
The physical analytical data of (L1,L2) and their metal complexes are given in table (1) and table (2). In a
satisfactory agreement with the calculated values, the suggested molecular which are formulas also supported by
subsequent spectral and elemental analysis as well as magnetic moment and conductivity.
Table (1): Physical analytical data of (L1) and their metal complexes (M1-M5)
Comp.
symbol
Colour
Melting
point ºC
Yield
%
M:L in
EtOH
Elemental analysis
Found
Calculate
L1
Greenish-
yellow
(167-
168)
53
M1
Reddish-
brown
190 dec.
79
1:1
17.71
18.45
M2
Deep red
(110-
112)
87
1:1
10.27
11.09
M3
Brownish-
black
(154-
156)
80
1:1
16.36
13.5
M4
Deep brown
216 dec.
48
1:1
12.7
10.37
M5
Reddish-
brown
(225-
226)
75
1:1
27.996
26.5
Table (2): Physical analytical data of (L2) and their metal complexes (F1-F5)
Comp.
symbol
Colour
Melting
point ºC
Yield
%
M:L in
EtOH
Elemental analysis
Suggested formula
Found
Calculate
L2
reddish-
orange
(200-
201)
46
C16H12N2OBr
F1
light-green
160 dec.
73
1:2
5.9
7.7
[Cu(C16H12N2OBr)2.Cl2]
F2
Brown-
gray
172 dec.
81
1:1
12.58
11.31
[Ni(C16H12N2OBr)Cl.EtOH].Cl
F3
Greenish-
gray
(127-
129)
74
1:2
6.56
6.83
[Co(C16H12N2OBr)2Cl.EtOH].Cl
F4
Yellow
150 dec.
54
1:2
6.5
6.4
[Cr(C16H12N2OBr)2Cl2]
F5
Brown-
Black
117 dec.
82
1:2
6.5
8.31
[Fe(C16H12N2OBr)2Cl.EtOH].Cl
B-The Infrared spectra of (L1,L2) and their complexes:
Schemes (1) were summarized the synthesis of different derivatives of hipuric acid (compound 1).
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
[phenyl-carbonyl amino]acetic acid (1) have been
synthesized by the reaction of benzoyl chloride with glycine in the presence of sodium hydroxide. The
reaction is followed by decreasing of absorption band for (υC=O ) at 1741 cm-1 and appearance of new absorption band
at 3280 cm-1 due to NH). Inthe 1H NMR spectra, the proton signals due to (CO-CH2-NH) was recorded at 4.67 ppm
integrating for two protons. The treatment of compound (1) with aryl aldehyde in presence of acetic acid and acetic
anhydride led to the formation of 4-(arylidene)-2-phenyl-1,3-oxazol-5(4H)-one(2a-b). Compounds (2a-b) have been
identified by IR spectrum which it showed the appearance of characteristic absorption bands near 1795-1798 cm-1
which belonged to the oxazol-5(4H)-one carbonyl group (oxazole,υC=O), and at 3146-3190 cm-1 due to (olifinicυCH),
1H NMR spectra showed signals at 8.46-8.69 ppm due to (CH, olifenic) and at 6.57-7.95 ppm which belonged to
aromatic protons.Refluxing compounds (2a-b) with hydrazine hydrate (99%) for 20 hrs offered good yields of the
corresponding derivatives (3a-b). The IR spectra of compounds (3a-b) displaced peaks at 1637-1712 cm-1, 3223-3350
cm-1 for (imidazole, υC=O) and NH2) functions respectively. 1H NMR spectrashowed signals at 8.77-8.82 ppm due to
(NH2), at 8.19-8.89 ppm for (CH, olifenic) and at 6.76 8.00ppm which belonged to aromatic protons.
Important information obtained from the FTIR spectrum of L1 and L2complexes which are summarized in
tables 3 & 4. Some bands which were appeared at 1708(v.sh) in L1 and at 1712(sh) in L2were shifted to lower
frequencies in comparison with ligands were appearing at about 1645(sh) in M1, 1643(w) in M2, 1641(w) in M3,
1640(w) in M4 and at 1645(m) in M5 also bands appeared at 1627(sh) in F1, 1643(sh) in F2, 1637(sh) in F3,
1647(v.sh) in F4 and at 1641(w) in F5 that belong to the typicalυ(C=O) of imidazol ringthat indicated coordination of
ligands with metal ions through the O atom of C=O group[23,24].
The typical υ(N-NH2) band for lactam in L1 appeared at 3327(sh) wasshifted to 3444(br) in M1, 3414(br) in
M2, 3404 in M3, 3383 in M4 and at 3452 in M5 , also the band appeared in L2 at 3277(m) was shifted to 3360(w) in
F1, 3336(br) in F2, 3308(br) in F3, 3327(w) in F4 and at 3329(br) in F5 that indicated coordination of ligands with
metal ions through the N atom of NH2group[25,26].
At last, the new bands appearing at 542(w), 496(w) and 415(w) in M1; at 532(w), 462(w), 425(w) in M2;
530(w), 470(w), 424(w) in M3, 545(m), 482(w), 403 in M4 and at 561(w), 488(w) and 430(m) in M5and at about
499(sh), 434(m) and 420(w) in F1; at 500(w), 453(w), 435(w) in F2; 501(m), 457(w), 405(m) in F3, 504(m), 447(w),
422(m) in F4 and at 498(sh), 434(m) and 410(m) in F5are attributed to (M-O), (M-N) and (M-Cl) stretching vibration
respectively in complexes of L1&L2 which are absent in ligands spectra[27,28].
Finally there are broad absorption bands appearing at about 3449(br) cm-1 in M1, 3414(br) cm-1 in M2,
3408(br) cm-1 in M3, 3400(br) cm-1 in M5 and about 3335(br) cm-1 in F2, 3377(br) cm-1 in F3, 3379(br) cm-1 in F5
COCl CONHCH2COOH
NH2CH2COOH
NaOH
AC2O/ACOH
ArCHO
X
C -H
O
N
O
X = N(CH3)2 , Br
N2H4X
C -H
N
N
O
NH2
12a - b
3a - b
Scheme 1
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
attributed to the υ(OH), indicate the presence of coordinated solvent molecules (Ethanol) in those complexes[29]. In
addition, the bands appearing at 696(m) cm-1 in M1, 698(m) cm-1 in M2, 692(m) cm-1 in M3, 650(m) in M5 and
692(m) in F2, 690(m) in F3, 694(m) in F5 resulting from δ(OH) bends also supports this conclusion[30,31].
Table (3): Characteristic stretching vibration frequencies (cm-1) located in FT-IR of (L1) and their metal
complexes (M1-M5)
Compound
symbol
νC=Ofor
Imidaol
νC-
NforImidaol
νN-NH2for
lactam
νM-O
νM-N
νM-Cl
L1
1651(s)
1257(m)
3298(sh)
M1
1599(s)
1231(w)
3228(m)
542(w)
496(w)
415(w)
M2
1645
1236(m)
3323(br)
532(w)
462(w)
435(w)
M3
1641
1236(w)
3383(br)
530(w)
470(w)
424(w)
M4
1641(w)
1225(w)
3283(br)
545(m)
482(w)
403(w)
M5
1645(m)
1298(m)
3186(w)
561(w)
488(w)
430(m)
Table (4): Characteristic stretching vibration frequencies (cm-1) located in FT-IR of (L2) and their metal
complexes (F1-F5)
Compound
symbol
νC=Ofor
Imidaol
νC-
NforImidaol
νN-NH2for
lactam
νM-O
νM-N
νM-Cl
L2
1712(sh)
1249(m)
3277(w)
F1
1627(sh)
1273(w)
3360(w)
499(sh)
434(m)
420(w)
F2
1643(m)
1213(m)
3303(br)
500(w)
453(w)
435(vw)
F3
1637(sh)
1213(w)
3308(br)
501(m)
457(vw)
405(m)
F4
1647(sh)
1298(m)
3221(br)
504(m)
447(w)
422(m)
F5
1641(sh)
1250(w)
3329(br)
498(sh)
434(m)
410(m)
Note: sh=sharp, br=broad, m=medium, w=weak
The Electronic spectra of (L1) and their complexes:
The UV spectrum of (L1) showed intense bands at 47619 cm-1 belong to 𝜋 → 𝜋* and at 28735 cm-1 and at
21645 cm-1 belong to 𝑛 → 𝜋* [25], table 5.
[M1]:- The UV-visible spectrum of deep- reddish brown of palladium complex with (L1) exhibited a weak shoulder
at (12658cm-1, 790nm) due to [1A1g→1E1g] transition, which is equal to the value (10Dq) for square planner
configuration[32]. It is also gave another band at (15151cm-1, 660nm) due to [1A1g→1B1g] transition, and another
strong band at (38461cm-1, 260nm) due to charge transfer between metal and ligand[33]. The diamagnetic
propertyof the complex agree well with electronic transition of low spin (d8) of palladium (II) complexes, which is
the only case in square planner environment[34,35]. The conductance measurements indicate that this complex was
to be ionic, table (5).
[M2]:- The electronic spectrum of deep- red complex of nickel with (L1) exhibited two bands one at (21052cm-1,
475nm) due to [3T1g→3A2g] transition and another band at (15873cm-1, 630nm) due to [3T1g(F)→ 3T2g(P)]
transition[32], which is equal to the value (10Dq) for octahedral configuration[36]. In addition the effective
magnetic moment at room temperature for the prepared complex was found to be (2.2 B.M), that refers to high spin
(d8) of nickel (II) complexes[37].The conductivity measurements in (DMSO) showed a electrolytic behavior for
complex, which is in a good agreement with that reported for tetrahedral geometry[38]. Table (5).
[M3]:- The UV-visible spectrum of brownish-black of cobalt complex with (L1) exhibited a weak shoulder at
(14619cm-1, 684nm) due to [4A2g(F)→4T2g(F)] transition, which is equal to the value (10Dq) for distorted
octahedral configuration[36]. It is also gave another two bands, one at (17985cm-1, 556nm) due to
[4A2g(F)→4T1g(F)] transition, and another band at (21834cm-1, 258nm) due to [4A2g(F)→4T1g(P)] transition[39].
The measured effective magnetic moment at room temperature for this complex was found to be (3.84 B.M), which
refers to high spin (d7) of cobalt (II) complexes[40].The conductivity measurements showed a electrolytic behavior
for complex, which is in a good agreement with that reported for octahedral geometry[41,42].
[M4]:- The electronic spectrum of this deep brown of chromium complex with (L1) gave a shoulder band at
(20833cm-1, 480nm) due to [4A2g(F)→4T2g(F)] transition, which is equal to the value (10Dq) for octahedral
configuration[43]. It is also gave another two bands at (27700cm-1, 361nm) due to [4A2g(F)→4T1g(F)] transition,
(38759cm-1, 258nm) due to [4T2g(F)→4T1g(F)] transition[38]. The measured effective magnetic moment at room
temperature for the prepared complex was found to be (4.23 B.M), which refers to (d3) of chromium (III)
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
complexes[44].The conductivity measurements in (DMSO) showed a non- conductive behavior for this complex,
table (5).
[M5]:- The UV-visible spectrum of this deep brown of platinum complex with (L1) showed three bands, the first one
appeared at (15197cm-1, 658nm) due to (d-d) transition, which is equal to the value (10Dq) for octahedral
configuration[39].The second band appeared at (20533cm-1, 487nm) due to [3A1g(F)→3T2g(F)] transition[45].
While the third one which refers to charge transfer transition appeared at (28653cm-1, 349nm). The effective
magnetic moment at room temperature for this complex showed low spin octahedral (d6) of Platinum (IV)
complexes which found to be (0.0 B.M)[46].The conductivity measurements in (DMSO) showed a a electrolytic
behavior for complex, table (5).
The Electronic spectra of (L2) and their complexes:
The UV spectrum of (L2) showed intense bands at 48780 cm-1 and at 44642cm-1 belong to 𝜋 → 𝜋* and at
33670 cm-1 belong to 𝑛 → 𝜋* [25]. Table 6.
[F1]:- The electronic spectrum of light- green cupper complex with (L2) exhibited only a broad overlapping band at
(12500cm-1, 800nm) due to [2Eg→2T2g] transition[47]. In addition the measured effective magnetic moment at room
temperature for complex was found to be (1.67 B.M), which refers to low spin distorted octahedral (d9) of cupper
(II) complexes[44]. The complex was paramagnetic and the conductance measurements indicate that this complex
was to be a nonionic, table (6).
[F2]:-The electronic spectra of L2 and its brown- red complex of nickel are similar. The complex spectrum exhibited
two bands at (31948cm-1, 313nm) due to [n→π*] transition and at (43290cm-1, 231nm) due to [π→π*] transition that
shifted to upper frequency.Thishypsochromic shifts of about (16&7) nm respectively are caused by the coordination
of N and O atoms of imidazole ring to Ni ion, which can also provide the conclusion evidence for the
coordination[30].The d-d transitions corresponded to [1A1g→1B1g] and [1A1g(F)→ 2B2g(P)] for square planner were
masked by high intensity band of intra-ligand charge transfer (INCT)[48]. The diamagnetic property of complex
agree well with electronic transition of low spin (d8) of nickel (II) complexes, which is the only case in square
planner environment[36,49].The conductance measurements in (DMSO) showed electrolytic behavior in (1:1) ratio.
This data was considered to cooperate with proposed formula [Ni(L2)(EtOH)Cl]Cl, table (6).
[F3]:- The electronic spectrum of greenish-gray complex of cobalt with (L2) exhibited three absorption bands. The
first band appeared at (15290cm-1, 654nm) due to [4A2g(F)→4T1g(F)] transition, which is equal to the value (10Dq)
for destroyed octahedral configuration[32]. The second band appeared at (16447cm-1, 608nm) due to
[4T1g(F)→4T1g(P)] transition, while the third band appeared at (17699cm-1, 565nm) due to [4T1g(F)→4T2g(P)]
transition[43]. The position of these bands are in a good agreement with that reported for octahedral geometry[36].
The measured effective magnetic moment at room temperature for complex was found to be (3.77 B.M), which
refers to high spin (d7) of cobalt (II) complexes[47,50]. Conductivity measurements in (DMSO) indicate electrolytic
behavior for complex, Table (6).
[F4]:- The UV-visible spectrum of yellow complex of chromium with (L2) showed a two bands, one appeared at
(16666cm-1, 600nm) due to [4A2g(F)→4T2g(F)] transition, the other broad band appeared at (24937cm-1, 401nm) due
to [4A2g(F)→4T1g(F)] transition[32]. while the third one which refers to charge transfer transition appears at
(25839cm-1, 387nm). The measured effective magnetic moment at room temperature for the prepared complex was
found to be (4.5 B.M), which is in agreement with (d3) octahedral geometry of chromium (III) complexes[44].
Conductivity measurements in (DMSO) showed a non- conductive behavior for this complex, table (6).
[F5]:- The electronic spectrum of black complex of Iron with (L2) showed three absorption bands appeared at
(16051cm-1, 623nm), (16447cm-1, 608nm) and (14164cm-1, 706nm) due to [4A1g→4T1g(G)], [4A1g→4Eg,4A1g(G)]
and [4A1g→4T1g(P)]transition respectively[51]. The paramagnetic property at room temperature of the complex
indicate a low spin octahedral (d5) of ferric (III) complexes and it was found to be (1.8 B.M)[52].The conductivity
measurements in (DMSO) showed anelectrolytic behavior in (1:1) ratio, table (6).
Table (5): Electronic spectra, Conductance in (DMSO) and Magnetic moment (B.M) for (L1) and their metal
complexes (M1-M6)
Compound
symbol
Bands (cm-1)
(nm)
Assignment
Molar
conductivity
(µs.cm-1)
µeff.
(B.M)
Suggested
structure
L1
47619 (210)
28735 (348)
21645 (462)
π→π
n→π
n→π
19.9
M1
38461 (260)
15151 (660)
12658 (790)
C.T.
[1A1g→1B1g]
[1A1g→1E1g]
32.5
0.0
Square planner
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
M2
21052 (475)
15873 (630)
[3A2g→3T1g(F)]
[3T1g(F)→3T1g(P)]
43
2.2
Tetrahedral
M3
21834 (458)
17985 (556)
14619 (684)
[4A2g(F)→4T1g(P)]
[4A2g(F)→4T1g(F)]
[4A2g(F)→4T2g(P)]
42.8
3.9
Distorted
octahedral
M4
17921 (558)
15015 (666)
12771 (783)
C.T.
[4A2g(F)→4T1g(F)]
[4A2g(F)→4T2g(P)]
24.1
4.1
Octahedral
M5
12658 (790)
[3A1g(F)→3T1g(F)]
63.3
0.0
octahedral
Table (6): Electronic spectra, Conductance in (DMSO) and Magnetic moment (B.M) for (L2) and their metal
complexes (F1-F6)
Comp.
symbol
Bands (cm-
1)(nm)
Assignment
Molar
conductivity
(µs.cm-1)
µeff.
(B.M)
Suggested
structure
L2
48780 (205)
44642 (224)
33670 (297)
π→π
π→π
n→π
22.7
F1
12500 (800)
[2Eg→2T2g]
20.2
1.67
Distorted
Octahedral
F2
33783 (296)
11248 (889)
[3A2g→3T1g(F)]
[3T1g(F)→3T1g(P)]
50.8
0.0
Square
planner
F3
17699 (565)
16447 (608)
15290 (654)
[4A2g(F)→4T1g(P)]
[4A2g(F)→4T1g(F)]
[4A2g(F)→4T2g(P)]
44.5
3.77
Octahedral
F4
16666 (600)
13793 (725)
[4A2g(F)→4T1g(F)]
[4A2g(F)→4T2g(F)]
5.7
4.5
Octahedral
F5
16447 (608)
16051 (623)
14164 (706)
[4A1g(F)→4T1g(P)]
[4A1g(F)→4T1g(G)]
[4A1g(F)→4Eg,4A1g(G)]
45.9
1.8
Octahedral
The Antimicrobial Activity of(L1, L2) and their complexes were tested against pathogenic isolates(Esherichia
coli, Pseudomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Enterococcus faecalis and Candida
albicans) using well diffusion technique. The diameter of inhibition zones around each well with (L1, L2) and their
complexes is represented in table (7). The highest Antimicrobial Activity was observed against Pseudomonas
aeruginosa. No inhibition activity was noticed from all prepared compounds against Candida albicans.(Ni+L1) and
(La+L1) complexes were found to be the most effective agent against bacterial isolates, while (Fe+L2) was the
lowest effective agent.
On the other hand the synergism effect of (L1, L2) and their complexes were tested against Staphylococcus
aureus and Esherichia coli. The results showed non effect for all compound against Staphylococcus aureus. (Ni+L2)
+ (Pd+L1) and (Co+L1) + (Fe+L2) complexes mixtures were effected with Esherichia coli, the inhibitor zone
diameter was (11mm, 10mm) respectively, table (8).
Table (7):- Antimicrobial Activity of (L1, L2) and their complexes
Isolate
compound
s
Inhibition Zone diameters (mm) aganist
Pseudomonas
aeruginosa (G-
ve)
Esherichia
coli (G-ve)
Enterococcus
faecalis
(G+ve)
K.
pneumemae(G-
ve)
Staphylococcus
aureus (G+ve)
Pt+L1
18
14
16
11
Co+L1
22
14
15
11
Cr+L1
21
15
15
Ni+L1
25
15
13
12
La+L1
25
15
13
13
Pd+L1
21
15
13
13
L1
20
15
12
15
15
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
Cu+L2
20
15
14
16
12
La+L2
20
14
12
13
Fe+L2
14
12
Cr+L2
17
14
11
Co+L2
17
14
11
11
Ni+L2
14
15
12
12
L2
13
Table (8):- Synergism Affectof (L1, L2) and their complexes
Mixture
Staphylococcus aureus
Esherichia coli
(Pt+L1)&(Cu+L2)
(Co+L1)&(La+L2)
(Cr+L1)&(Fe+L2)
(Ni+L1)&(Cr+L2)
(La+L1)&(Co+L2)
(Pd+L1)&(Ni+L2)
11mm
(L1)&(L2)
(Co+L1)&(Fe+L2)
10mm
(Ni+L1)&(Cu+L2)
(Pd+L1)&(Cr+L2)
(Ni+L1)&(Fe+L2)
(Pd+L1)&(Cu+L2)
(Pd+L1)&(Fe+L2)
(La+L1)&( Fe+L2)
The suggested stereo geometrical structure of L1& L2 with their metal complexes (M1-M5) and (F1-F5):
(H3C)2N
C -H
N
N
O
NH2
Pt
Cl
Cl HOEt
. 2Cl
EtOH
(H3C)2N
C -H
N
N
O
NH2
M
Cl
HOEt
.Cl.EtOH
M=Pd, Ni
Br
C -H
N
N
O
NH2
Br
C -H
NN
O
NH2
M
Cl
Cl
M=Co, Cr, Fe
Br
C -H
N
N
O
NH2
.Cl
HOEt
Ni+Cl
(H3C)2N
C -H
N
N
O
NH2
Co
Cl
Cl HOEt
.Cl
EtOH
(H3C)2N
C -H
N
N
O
NH2
Cr2+
Cl
EtOH
Cl
Cl
ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 , 399-408
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ISSN 2320-5407 International Journal of Advanced Research (2014), Volume 2, Issue 3 ,
399-408
409
... Then, the mixture was allowed to cool to room temperature and pyridine was removed. The product was recrystallized from ethanol to afford the desired compound (26) . The percent yield, physical parameters, melting point and R f values results are listed in Table (1). ...
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Chapter
The elements of the first transition series are those for which the 3d electron shell contains between one and nine electrons. Copper is included because, although its outer electronic configuration is 3d10 4s1, it has the 3d9 configuration in its commonly occurring +2 oxidation state. Zinc is not normally considered a transition element since in both the element and its compounds the 3d electron shell remains filled. It therefore does not show the characteristic properties of coloured compounds and paramagnetism shown by the other elements in at least one of their oxidation states. Scandium is included by the definition, but so far only the +3 oxidation state has been established with certainty. Its compounds are thus diamagnetic with no colour from d—d transitions, and its chemistry thus resembles that of aluminium rather than that of the other transition elements. We shall not deal specifically with its chemistry here; interested readers should consult Remy.