Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-indolinone were prepared. Their structure was established to be [MLC]Cl-. by using elemental analysis and molar conductivity. as well as AA, FTIR, UV/VIS and H-1-NMR spectroscopic methods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II) complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes were tested for antibacterial activity against Slaphylococcus aureus, Enterococcus D. Proteus mirabilis. Escherichia coli. Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans

Cakic, Z

Konstantinovic, SS

Radovanovic, BC

Vasić, Vesna M.

Journal of the Serbian Chemical Society

Sandra Konstantinovic

Blaga Radovanovic

Zivojin Cakic

Vesna Vasic

Crossref

Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3-salicylidenehydrazono-2-indolinone

Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-indolinone were prepared. Their structure was established to be [MLCl].Cl by using elemental analysis and molar conductivity, as well as AA, FTIR, UV/VIS and 1H-NMR spectroscopic methods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II) complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes were tested for antibacterial activity against Staphylococcus aureus, Enterococcus D, Proteus mirabilis, Escherichia coli, Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans

VESNA VASIC

ZIVOJIN CAKIC

BLAGA C. RADOVANOVIC

SANDRA S. KONSTANTINOVIC

Directory of Open Access Journals

Radovanović, Blaga

Repository of the Vinča Nuclear Institute (VinaR)

J.Serb.Chem.Soc. 68(8–9)641–647(2003) UDC 547.576+546.47+546.56+546.735.74+543.422.25:615.281JSCS – 3072 Original scientific paperSynthesis and characterization of Co(II), Ni(II), Cu(II) andZn(II) complexes with 3-salicylidenehydrazono-2-indolinoneSANDRA S. KONSTANTINOVI]1,*, BLAGA C. RADOVANOVI]2, @IVOJIN CAKI]3 andVESNA VASI]4,#1Faculty of Technology, Bulevar Oslobodjenja 124, 16000 Leskovac, 2Department of Chemistry, Faculty ofScience, ]irila i Metodija 2, 18000 Ni{, 3Institute of Health Protection, 16000 Leskovac and 4INN Vin~a,11000 Belgrade, Serbia and Montenegro(Received 3 December 2002, revised 16 April 2003)Abstract: Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-in-dolinone were prepared. Their structure was established to be MLCl.Cl by using elementalanalysis and molar conductivity, as well as AA, FTIR, UV/VIS and 1H-NMR spectroscopicmethods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II)complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes weretested for antibacterial activity against Staphylococcus aureus, Enterococcus D, Proteusmirabilis, Escherichia coli, Bacillus anthracis, Pseudomonas aeruginosa and Candidaalbicans.Keywords: isatin, salicylaldehyde, transition metal complexes, FTIR, UV/VIS, 1H-NMR,antibacterial activity.INTRODUCTIONThe synthetic versatility of isatin has led to the extensive use of this compound in or-ganic synthesis, which stemmed from the interest in the biological and pharmacologicalproperties of its derivatives.1 It is also known that mono- and bishydrazones find wide ap-plication in medicine as active physiological preparations, due to their antibacterial,tuberculostatic, fungicidal properties2,3 as well as activities against certain types of cancersand microorganisms. Benzylidene derivatives have also found wide application, not onlybecause of their strong activity against some micoorganisms, but also because they can actas free radical scavengers. Many coordinaton compounds of transition metals with Schiffbases show greater activity than the ligands alone.2–5The present paper describes the synthesis of the salicylaldehyde -hydrazone of isatin(L), and the preparation and spectral characteristics of its Co(II), Ni(II), Cu(II) and Zn(II)641* Corresponding author: E-mail: andjelkovic_s@yahoo.com# Serbian Chemical Society active membercomplexes. The synthesized compounds were tested for antibacterial activity againstStaphylococcus aureus ATCC 6538, Enterococcus D, Proteus mirabilis, Escherichia coli95, Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans ATCC 10231 bythe disk method and also by the standard minimum inhibitory concentration (MIC) of se-rial dilution test.EXPERIMENTALMaterials, methods and instrumentsThe chemical used were of AR grade.Microanalysis for carbon, hydrogen and nitrogen was carried out with a Carlo Erba 1106microanalyser. The chloride content was determined by the Mohr method. The metal contents weredetermined using a Virial AA-457 Double beam spectrometer. The molar conductivity of the com-plexes was measured with an Iskra Conductivity Meter 0.67 using 10–3 mol dm–3 solutions in DMF.The Fourier transformed infrared (FTIR) spectra were recorded using a Michaelson Bomen MB-se-ries spectrophotometer, using the KBr pellet (1 mg/100 mg) technique. The electronic spectra(UV/VIS) were recorded on a Perkin-Elmer Lambda 15 UV/VIS spectrophotometer using 10–3 moldm–3 solutions in DMF. The nuclear magnetic resonance (1H-NMR) spectra were obtained inDMSO solution with a GEMINI-200 “HF NMR” spectrometer.For the disk method, stock solutions of 15 mg cm–3 concentration were made with a solventmixture of 50 % DMF and 50 % 0.1 mol dm–3 NaOH. Onto disks, 210–6 dm3 of stock solution wasdropped, and then dried at room temperature. Suspensions were made from the 24-hour blood agarculture of the bacteria and incubated at 310 K for 3 h. The bacteral suspension was transferred to theantibacterial test medium and the disk was placed on it. After incubation at 310 K for 18 h, the incu-bation zones were measured (mm). The antimicrobial activity was determined by following the bac-terial growth at 37 ºC in the nutrition medium for 24 h. The concentration of the tested compounds atwhich no increase of optical density was observed after an incubation time of 24 h, were accepted asthe minimal inhibitory concentration (MIC).6Synthesis of ligands and complexesSynthesis of salicylaldehyde -hydrazone of isatin. The -hydrazone of isatin (synthesized by astandard procedure4,5) was dissolved in the minimum amount of 95 % ethanol. To this solution,salicylaldehyde was added in an equimolar amount under continuous refluxing for about 45 min.The mixture was acidified with H2SO4 to pH 4 – 4.5. The colored product was filtered, washed withethanol and dried in vacuo over CaCl2.Synthesis of the complexes. For the synthesis of the complexes, the salicylaldehyde -hy-drazone of isatin was dissolved in the minimum amount of 95 % ethanol. To this refluxing solution,metal(II) chloride was added in equimolar amounts. The refluxing was continued for about 2 h. Thecolored products were filtered, washed with ethanol and dried in vacuo over CaCl2.RESULTS AND DISCUSSIONThe results of elemental analysis and some physical characteristics of the obtained com-pounds are given in Table I. The complexes were synthesized using a 1:1 mole ratio of all re-actants. The elemental analysis (Table I) of the complexes indicates a 1:1 metal to ligandstoichiometry, too. The complexes are air-stable, non-hygroscopic, with high melting points,insoluble in H2O, but partly soluble in ethanol. They are also soluble in certain solvents suchas DMF and DMSO. The molar conductivities of 10–3 mol dm–3 solutions of the complexesin DMF (Table I) indicate that the complexes behave as electrolytes6 in DMF.642 KONSTANTINOVI] et al.TABLE I. Analytical and physical data of the investigated compoundsComp. Yield/% Color M.p./ºCAnalysis (%) found (Calcd) Mol. cond.S cm2 mol–1C H N Cl ML 89.65 light- 175 66.90 4.10 15.60 – – –red (67.92) (4.15) (15.84)[CoLCl].Cl 35.12 blue 190 45.65 2.50 10.73 14.85 18.09 89(45.69) (2.54) (10.66) (14.95) (18.02)[CuLCl].Cl 45.63 brown 195 45.00 2.12 10.23 17.65 15.69 90(45.17) (2.51) (10.54) (17.82) (15.93)[NiLCl].Cl 41.25 dark- 184 45.35 2.35 10.45 18.10 15.01 88red (45.72) (2.54) (10.66) (18.02) (14.95)[ZnLCl].Cl 36.06 red 203 45.02 3.00 10.40 17.69 16.69 85(44.95) (2.49) (10.48) (17.73) (16.33)Electronic absorption spectraThe spectral data of the compounds in DMF are presented in Table II. There are two ab-sorption bands, assigned to n–* and –* transitions, in the electronic spectrum of the ligand.These transitions are also found in the spectra of the complexes, but they are shifted towardslower and higher frequencies, confirming the coordination of the ligand to the metallic ions.TABLE II. Electronic spectral data and magnetic moments of the complexes recorded in DMF fre-quency(cm–1)/max.10–3 (mol–1 dm3 cm–1)Compound (103 cm–1)/ geometry eff/BLigand 36.8/1637 – –30.8/1627[CoLCl].Cl 37.7/751 4.5629.9/69816.4/391 Tetrahedral15.9/45115.5/381[CuLCl].Cl 37.7/732 1.8825.9/61421.4/412 Square-planar15.5/384[NiLCl].Cl 37.7/761 diam.28.5/62318.9/596 Square-planar13.5/488[ZnLCl].Cl 37.8/847 –29.5/573 Tetrahedral26.9/514Co(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 643The visible electronic absorption spectrum of the cobalt(II) complex is dominated bythe highest energy 4A2  4T1(P) transition, which is a typical one for tetrahedral Co(II)complexes. The magnetic moment value (Table II) and the blue color of the cobalt(II)complex, also suggest tetrahedral stereochemistry.6,12The electronic spectrum of the copper complex exhibits bands at 21400 cm–1 and15500 cm–1 which can be assigned to 2B1g  2A1 and 2B1g  2E1g transitions.8,17 Thesetransitions, as well as the measured value of the magnetic moment (eff = 1.88 B) suggesta square-planar stereochemistry of the compound.The electronic spectrum of the nickel complex shows the two bands at 18900 cm–1and 13500 cm–1 which are attributed to 1A1g  1A2g and 1A1g  1B2g transitions.8 Thesetransitions, as well as the measured value of the magnetic moment (eff = 0) suggest asquare-planar stereochemistry of the compound.Since the zinc ion has d10 configuration, the absorption at 26900 cm–1 could be as-signed to a charge transfer transition.4,5 However, taking into account the spectrum and theconfiguration of the zinc(II) ion, a tetrahedral geometry8 could be assumed for its complex.Infrared spectraThe main frequencies and their assignments are presented in Table III.An –OH stretching vibration appears at 	 3541 cm–1 in the spectrum of ligand. Thisband is strong, probably, because of intramolecular hydrogen bond formation between thenitrogen atom of azomethine group and the hydrogen atom of the –OH group. This func-tional group also shows a specific in-plane deformation vibration. The large band at 	 1340cm–1 confirms the intramolecular hydrogen bonding of this group. The salicylaldehyde-hydrazone of isatin also shows a –C(H)=N stretching band at 1585 cm–1,7 and a band at1359 cm–1, assigned to the vibration frequency of the phenolic C–O group.TABLE III. FTIR spectral data of the compounds frequency (cm–1)CompoundAssigment of bandsa(OH) (NH) (C=O) (C=N)1 (CH=N)2 (C-O) M-N M-OL 3541m; l 3400m 1730s 1615m 1585w 1359w – –[CoLCl].Cl – 3400m 1706m 1616w 1545w 1386m 455m 487m[CuLCl].Cl – 3400m 1704m 1618w 1560w 1367m 461m 498m[NiLCl].Cl – 3376m 1698s 1615w 1545w 1378m 440w 498w[ZnLCl].Cl – 3361s 1685s 1616w 1550w 1368m 458m 491maRelative intensity: s–strong, m–medium, w–weak, l–large; 1Vibrations of group from the -hydrazone ofisatine; 2Vibrations of the azomethine groupThe characteristics of the FTIR spectra of all complexes are in agreement with thesuggested structural formulae. The disappearance of the phenolic (OH) bond indicates thedeprotonation of this group and cleavage of the hydrogen bond, with involvement of theoxygen atom in bonding with the metal.7 In the complexes, the band assigned to the vibra-644 KONSTANTINOVI] et al.tion frequency of the phenolic C–O group undergoes positive shifts, indicating that theSchiff base is bonded to the metallic ions through the phenolic oxygen atoms.10 The bandscorresponding to (C=N) are shifted to lower frequencies ( = 5–23 cm–1) in the spec-trum of the complexes. This indicates that the C=N group is a coordination site of theligand. It also can be seen that the bands corresponding to (C=O) are shifted to lower fre-quencies ( = 11–24 cm–1) in the spectra of the complexes. This indicates that the C=Ogroup is also a coordination site of the ligand.5,7,8Thus, knowledge gained from the infrared spectra provides clear evidence that theligand is bonded as a tridentate by the nitrogen and oxygen atom from the isatin as well asthrough the oxygen atom from the salicylaldehyde part of the molecule.Nuclear magnetic resonance1H-NMR data of the ligand and complexes are listed in Table IV.In the spectrum of -HI, the –NH group resonance signal is observed as a singlet at8.234 ppm. The –NH2 group resonance signal appears as a singlet at 10.694 ppm. Thecharacteristic two doublets and two triplets of the substituted phenyl ring in this spectrumare observed at 6.839–7.375 ppm.The signal of the –NH2 group is not found in the spectrum of salicylaldehyde-hydrazone of isatin, but a signal of a hydroxyl group appears at 12.56 ppm. In the spec-trum of the ligand, the –NH group resonance signal is also observed as a singlet at 8.054ppm. The signal of the azomethine HC=N proton is at 8.598 ppm. Thus, the appearance ofthe azomethine proton signal and the disappearance of the –NH2 group resonance signalboth suggest condensation of the -HI and carbonyl components.11,15TABLE IV. 1H-NMR data (/ppm) of the compoundsCompound(OH) (NH2) (NH) (=CH) (phenyl1) (phenyl2)HI – 10.694 8.324 – 6.839–7.375 –(s; 1H) (s; 1H) (m; 4H)L 12.56 – 8.354 8.598 6.853–7.169 7.188–7.391(s; 1H) (s; 1H) (s; 1H) (m; 4H) (m; 4H)[CoLCl].Cl – – 8.250 8.581 6.850–7.195 7.180–7.398(s; 1H) (s; 1H) (m; 4H) (m; 4H)[CuLCl].Cl – – 8.256 8.580 6.849–7.196 7.181–7.399(s; 1H) (s; 1H) (m; 4H) (m; 4H)[NiLCl].Cl – – 8.255 8.581 6.849–7.195 7.180–7.399(s; 1H) (s; 1H) (m; 4H) (m; 4H)[ZnLCl].Cl – – 8.258 8.581 6.850–7.195 7.179–7.399(s; 1H) (s; 1H) (m; 4H) (m; 4H)1phenyl from the isatin part of the molecule; 2phenyl from the salicylaldehyde part of the moleculeCo(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 645The main difference in the spectrum of complexes is the absence of the OH proton lo-cated at 12.56 ppm in the free ligand. This indicates deprotonation of this group during co-ordination with metallic ion.6,7 Also, a downfield shift of –NH and =CH group resonancesignal in the complex compounds is related with a decrease of the electron density anddeshielding of both protons, as a result of the participation of the adjacent C=O and C=Ngroups in the coordination.13,14The structural formula of the complexes shown in Fig. 1 is consistent with the abovementioned data.Antimicrobial activityThe experimental inhibition zones (mm) and the MIC values are shown in Table V.As can be seen, all the compounds have different antibacterial activity in vitro against thetested bacterial organisms.15,16The results show that the bis-Schiff base exhibits the best activity against Staphylo-coccus aureus.TABLE V. Range of inhibition zones (mm) and MIC values (g cm–3) of the investigated compoundsCompoundE. coli P. mirabilis S. aureus E. group D B. anthracisP.aeruginosaC. albicansmm MIC mm MIC mm MIC mm MIC mm MIC mm MIC mm MICL 11 50–200 10 200–500 14 50–200 10 200–500 10 200–500 10 200–500 14 20–200[CoLCl].Cl 22 <50 19 <50 22 <50 19 <50 23 <50 22 <50 26 <50[CuLCl].Cl 22 <50 20 < 50 22 < 50 20 < 50 23 < 50 22 < 50 26 < 50[NiLCl].Cl 21 50–200 19 <50 21 < 50 16 50–200 20 < 50 20 < 50 25 < 50[ZnLCl].Cl 22 < 50 21 < 50 22 < 50 20 < 50 23 < 50 21 < 50 27 < 50An influence of the central ion of the complexes in the antimicrobial activity againstthe tested gram-positive and gram-negative organisms and yeast is evident. The results alsoshow that the complexes have an enhanced activity compared to the ligand itself. This is646 KONSTANTINOVI] et al.Fig. 1. The structure of the coordination compounds.especially shown against Candida albicans. The metal activity decreases in the order Zn Cu > Co > Ni.Acknowledgments: This work was supported by the Ministry of Science, Technologies and Develop-ment of the Republic of Serbia.IZVODSINTEZAIKARAKTERIZACIJACo(II),Ni(II),Cu(II)I Zn(II)KOMPLEKSASA3-SALICILIDENHIDRAZONO-2-INDOLINONOMSANDRAS. KONSTANTINOVI]1, BLAGAS. RADOVANOVI]2,@IVOJINCAKI]3 iVESNAVASI]41Tehnolo{kifakultet, BulevarOslobo|ewa 124, 16000 Leskovac, 2Prirodno-matemati~kifakultet,Odsek zahemiju, ]irila iMetodija 2, 18000Ni{, 3Zavod za za{titu zdravqa, 16000 Leskovac i 4INNVin~a, 11000BeogradSintetisani su kompleksiCo(II),Ni(II),Cu(II)iZn(II) sa 3-salicilidenhidrazono-2-indo-linonom. Izolovani kompleksi su okarakterisani elementalnom mikroanalizom, merewemmolarne provodqivosti, magnetne susceptibilnosti, AA, FTIR, UV/VIS i 1H-NMR spektro-skopskim metodama. Utvr|ena je kvadratno-planarna geometrija za Ni(II) i Cu(II), kao itetraedarska geometrija za Co(II) i Zn(II) komplekse. Sintetisanim jediwewima je ispitanabiolo{ka aktivnost u odnosu na Staphylococcus aureus, Enterococcus D, Proteus mirabilis, Esche-richia coli, Bacillus anthracis, Pseudomonas aeruginosa i Candida albicans.(Primqeno 3. decembra 2002, revidirano 16. aprila 2003)REFERENCES1. J. F. da Silva, S. J. Garden, A. C. Pinto, J. Braz. Chem. Soc. 12 (2000) 32. N. M. Samus, T. A. Burdenko, V. V. Gylka, V. I. Tsapkov, J. Chem. Pharma. 12 (1994) 403. V. I. Tsapkov, T. Mianperem, N. M. Samus, Russ. Gen. Chem. 65 (1995) 3204. B. C. Stoj~eva Radovanovi}, S. S. Andjelkovi}, J. Serb. Chem. Soc. 63 (1998) 3795. B. C. Stoj~eva Radovanovi}, S. S. Andjelkovi}, Analytical Laboratory 6 (1997) 1906. S. O. Podunavac-Kuzmanovi}, V. M. Leovac, N. U. Peri{i}-Janji}, J. Rogan, G. Bala{, J. Serb. Chem. Soc.64 (1999) 3817. A. Z. El-Sonbati, Spectroscopy Lett. 30 (1997) 4598. A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier, Amsterdam, 19849. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, Wiley, NewYork, 198610. A. Z. El-Sonbati, A. A. El-Bindary, Polish J. Chem. 74 (2002) 62111. J. Csaszar, J. Moway, O. Herceczeg, Acta Phys. Chem. 31 (1988) 71712. F. A. Cotton, G. Wilkinson, Advanced Inorganic Chemistry, Wiley, New York, 198913. J. M. Daw, W. Henderson, B. K. Nicholson, J. Chem. Soc. Dalton Trans. 45 (1997) 8714. A. M. Hassaan, M. A. Khalifa, A. K. Shehata, Bull. Soc. Chim. Belg. 104 (1995) 12115. N. C. Kasuga, K. Sekino, C. Koumo, N. Shimada, M. Ishikawa, K. Nomiya, J. Inorg. Biochem.84 (2001) 5516. K. Nomiya, K. Tsuda, T. Sudoh, M. Oda, J. Inorg. Biochem. 68 (1997) 3917. L. Larabi, Y. Hared, A. Reguig, M. Mostafa, J. Serb. Chem. Soc. 68 (2003) 85.Co(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 647

VinaR - Repository of the Vinča Institute of Nuclear Sciences

J.Serb.Chem.Soc. 68(8–9)641–647(2003) UDC 547.576+546.47+546.56+546.735.74+543.422.25:615.281
JSCS – 3072 Original scientific paper
Synthesis and characterization of Co(II), Ni(II), Cu(II) and
Zn(II) complexes with 3-salicylidenehydrazono-2-indolinone
SANDRA S. KONSTANTINOVI]1,*, BLAGA C. RADOVANOVI]2, @IVOJIN CAKI]3 and
VESNA VASI]4,#
1Faculty of Technology, Bulevar Oslobodjenja 124, 16000 Leskovac, 2Department of Chemistry, Faculty of
Science, ]irila i Metodija 2, 18000 Ni{, 3Institute of Health Protection, 16000 Leskovac and 4INN Vin~a,
11000 Belgrade, Serbia and Montenegro
(Received 3 December 2002, revised 16 April 2003)
Abstract: Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-in-
dolinone were prepared. Their structure was established to be MLCl.Cl by using elemental
analysis and molar conductivity, as well as AA, FTIR, UV/VIS and 1H-NMR spectroscopic
methods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II)
complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes were
tested for antibacterial activity against Staphylococcus aureus, Enterococcus D, Proteus
mirabilis, Escherichia coli, Bacillus anthracis, Pseudomonas aeruginosa and Candida
albicans.
Keywords: isatin, salicylaldehyde, transition metal complexes, FTIR, UV/VIS, 1H-NMR,
antibacterial activity.
INTRODUCTION
The synthetic versatility of isatin has led to the extensive use of this compound in or-
ganic synthesis, which stemmed from the interest in the biological and pharmacological
properties of its derivatives.1 It is also known that mono- and bishydrazones find wide ap-
plication in medicine as active physiological preparations, due to their antibacterial,
tuberculostatic, fungicidal properties2,3 as well as activities against certain types of cancers
and microorganisms. Benzylidene derivatives have also found wide application, not only
because of their strong activity against some micoorganisms, but also because they can act
as free radical scavengers. Many coordinaton compounds of transition metals with Schiff
bases show greater activity than the ligands alone.2–5
The present paper describes the synthesis of the salicylaldehyde -hydrazone of isatin
(L), and the preparation and spectral characteristics of its Co(II), Ni(II), Cu(II) and Zn(II)
641
* Corresponding author: E-mail: andjelkovic_s@yahoo.com
# Serbian Chemical Society active member
complexes. The synthesized compounds were tested for antibacterial activity against
Staphylococcus aureus ATCC 6538, Enterococcus D, Proteus mirabilis, Escherichia coli
95, Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans ATCC 10231 by
the disk method and also by the standard minimum inhibitory concentration (MIC) of se-
rial dilution test.
EXPERIMENTAL
Materials, methods and instruments
The chemical used were of AR grade.
Microanalysis for carbon, hydrogen and nitrogen was carried out with a Carlo Erba 1106
microanalyser. The chloride content was determined by the Mohr method. The metal contents were
determined using a Virial AA-457 Double beam spectrometer. The molar conductivity of the com-
plexes was measured with an Iskra Conductivity Meter 0.67 using 10–3 mol dm–3 solutions in DMF.
The Fourier transformed infrared (FTIR) spectra were recorded using a Michaelson Bomen MB-se-
ries spectrophotometer, using the KBr pellet (1 mg/100 mg) technique. The electronic spectra
(UV/VIS) were recorded on a Perkin-Elmer Lambda 15 UV/VIS spectrophotometer using 10–3 mol
dm–3 solutions in DMF. The nuclear magnetic resonance (1H-NMR) spectra were obtained in
DMSO solution with a GEMINI-200 “HF NMR” spectrometer.
For the disk method, stock solutions of 15 mg cm–3 concentration were made with a solvent
mixture of 50 % DMF and 50 % 0.1 mol dm–3 NaOH. Onto disks, 210–6 dm3 of stock solution was
dropped, and then dried at room temperature. Suspensions were made from the 24-hour blood agar
culture of the bacteria and incubated at 310 K for 3 h. The bacteral suspension was transferred to the
antibacterial test medium and the disk was placed on it. After incubation at 310 K for 18 h, the incu-
bation zones were measured (mm). The antimicrobial activity was determined by following the bac-
terial growth at 37 ºC in the nutrition medium for 24 h. The concentration of the tested compounds at
which no increase of optical density was observed after an incubation time of 24 h, were accepted as
the minimal inhibitory concentration (MIC).6
Synthesis of ligands and complexes
Synthesis of salicylaldehyde -hydrazone of isatin. The -hydrazone of isatin (synthesized by a
standard procedure4,5) was dissolved in the minimum amount of 95 % ethanol. To this solution,
salicylaldehyde was added in an equimolar amount under continuous refluxing for about 45 min.
The mixture was acidified with H2SO4 to pH 4 – 4.5. The colored product was filtered, washed with
ethanol and dried in vacuo over CaCl2.
Synthesis of the complexes. For the synthesis of the complexes, the salicylaldehyde -hy-
drazone of isatin was dissolved in the minimum amount of 95 % ethanol. To this refluxing solution,
metal(II) chloride was added in equimolar amounts. The refluxing was continued for about 2 h. The
colored products were filtered, washed with ethanol and dried in vacuo over CaCl2.
RESULTS AND DISCUSSION
The results of elemental analysis and some physical characteristics of the obtained com-
pounds are given in Table I. The complexes were synthesized using a 1:1 mole ratio of all re-
actants. The elemental analysis (Table I) of the complexes indicates a 1:1 metal to ligand
stoichiometry, too. The complexes are air-stable, non-hygroscopic, with high melting points,
insoluble in H2O, but partly soluble in ethanol. They are also soluble in certain solvents such
as DMF and DMSO. The molar conductivities of 10–3 mol dm–3 solutions of the complexes
in DMF (Table I) indicate that the complexes behave as electrolytes6 in DMF.
642 KONSTANTINOVI] et al.
TABLE I. Analytical and physical data of the investigated compounds
Comp. Yield/% Color M.p./ºC
Analysis (%) found (Calcd) Mol. cond.
S cm2 mol–1C H N Cl M
L 89.65 light- 175 66.90 4.10 15.60 – – –
red (67.92) (4.15) (15.84)
[CoLCl].Cl 35.12 blue 190 45.65 2.50 10.73 14.85 18.09 89
(45.69) (2.54) (10.66) (14.95) (18.02)
[CuLCl].Cl 45.63 brown 195 45.00 2.12 10.23 17.65 15.69 90
(45.17) (2.51) (10.54) (17.82) (15.93)
[NiLCl].Cl 41.25 dark- 184 45.35 2.35 10.45 18.10 15.01 88
red (45.72) (2.54) (10.66) (18.02) (14.95)
[ZnLCl].Cl 36.06 red 203 45.02 3.00 10.40 17.69 16.69 85
(44.95) (2.49) (10.48) (17.73) (16.33)
Electronic absorption spectra
The spectral data of the compounds in DMF are presented in Table II. There are two ab-
sorption bands, assigned to n–* and –* transitions, in the electronic spectrum of the ligand.
These transitions are also found in the spectra of the complexes, but they are shifted towards
lower and higher frequencies, confirming the coordination of the ligand to the metallic ions.
TABLE II. Electronic spectral data and magnetic moments of the complexes recorded in DMF fre-
quency(cm–1)/max
.10–3 (mol–1 dm3 cm–1)
Compound (103 cm–1)/ geometry eff/B
Ligand 36.8/1637 – –
30.8/1627
[CoLCl].Cl 37.7/751 4.56
29.9/698
16.4/391 Tetrahedral
15.9/451
15.5/381
[CuLCl].Cl 37.7/732 1.88
25.9/614
21.4/412 Square-planar
15.5/384
[NiLCl].Cl 37.7/761 diam.
28.5/623
18.9/596 Square-planar
13.5/488
[ZnLCl].Cl 37.8/847 –
29.5/573 Tetrahedral
26.9/514
Co(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 643
The visible electronic absorption spectrum of the cobalt(II) complex is dominated by
the highest energy 4A2  4T1(P) transition, which is a typical one for tetrahedral Co(II)
complexes. The magnetic moment value (Table II) and the blue color of the cobalt(II)
complex, also suggest tetrahedral stereochemistry.6,12
The electronic spectrum of the copper complex exhibits bands at 21400 cm–1 and
15500 cm–1 which can be assigned to 2B1g  2A1 and 2B1g  2E1g transitions.8,17 These
transitions, as well as the measured value of the magnetic moment (eff = 1.88 B) suggest
a square-planar stereochemistry of the compound.
The electronic spectrum of the nickel complex shows the two bands at 18900 cm–1
and 13500 cm–1 which are attributed to 1A1g  1A2g and 1A1g  1B2g transitions.8 These
transitions, as well as the measured value of the magnetic moment (eff = 0) suggest a
square-planar stereochemistry of the compound.
Since the zinc ion has d10 configuration, the absorption at 26900 cm–1 could be as-
signed to a charge transfer transition.4,5 However, taking into account the spectrum and the
configuration of the zinc(II) ion, a tetrahedral geometry8 could be assumed for its complex.
Infrared spectra
The main frequencies and their assignments are presented in Table III.
An –OH stretching vibration appears at 	 3541 cm–1 in the spectrum of ligand. This
band is strong, probably, because of intramolecular hydrogen bond formation between the
nitrogen atom of azomethine group and the hydrogen atom of the –OH group. This func-
tional group also shows a specific in-plane deformation vibration. The large band at 	 1340
cm–1 confirms the intramolecular hydrogen bonding of this group. The salicylaldehyde
-hydrazone of isatin also shows a –C(H)=N stretching band at 1585 cm–1,7 and a band at
1359 cm–1, assigned to the vibration frequency of the phenolic C–O group.
TABLE III. FTIR spectral data of the compounds frequency (cm–1)
Compound
Assigment of bandsa

(OH) 
(NH) 
(C=O) 
(C=N)1 
(CH=N)2 
(C-O) M-N M-O
L 3541m; l 3400m 1730s 1615m 1585w 1359w – –
[CoLCl].Cl – 3400m 1706m 1616w 1545w 1386m 455m 487m
[CuLCl].Cl – 3400m 1704m 1618w 1560w 1367m 461m 498m
[NiLCl].Cl – 3376m 1698s 1615w 1545w 1378m 440w 498w
[ZnLCl].Cl – 3361s 1685s 1616w 1550w 1368m 458m 491m
aRelative intensity: s–strong, m–medium, w–weak, l–large; 1Vibrations of group from the -hydrazone of
isatine; 2Vibrations of the azomethine group
The characteristics of the FTIR spectra of all complexes are in agreement with the
suggested structural formulae. The disappearance of the phenolic (OH) bond indicates the
deprotonation of this group and cleavage of the hydrogen bond, with involvement of the
oxygen atom in bonding with the metal.7 In the complexes, the band assigned to the vibra-
644 KONSTANTINOVI] et al.
tion frequency of the phenolic C–O group undergoes positive shifts, indicating that the
Schiff base is bonded to the metallic ions through the phenolic oxygen atoms.10 The bands
corresponding to 
(C=N) are shifted to lower frequencies (
 = 5–23 cm–1) in the spec-
trum of the complexes. This indicates that the C=N group is a coordination site of the
ligand. It also can be seen that the bands corresponding to 
(C=O) are shifted to lower fre-
quencies (
 = 11–24 cm–1) in the spectra of the complexes. This indicates that the C=O
group is also a coordination site of the ligand.5,7,8
Thus, knowledge gained from the infrared spectra provides clear evidence that the
ligand is bonded as a tridentate by the nitrogen and oxygen atom from the isatin as well as
through the oxygen atom from the salicylaldehyde part of the molecule.
Nuclear magnetic resonance
1H-NMR data of the ligand and complexes are listed in Table IV.
In the spectrum of -HI, the –NH group resonance signal is observed as a singlet at
8.234 ppm. The –NH2 group resonance signal appears as a singlet at 10.694 ppm. The
characteristic two doublets and two triplets of the substituted phenyl ring in this spectrum
are observed at 6.839–7.375 ppm.
The signal of the –NH2 group is not found in the spectrum of salicylaldehyde
-hydrazone of isatin, but a signal of a hydroxyl group appears at 12.56 ppm. In the spec-
trum of the ligand, the –NH group resonance signal is also observed as a singlet at 8.054
ppm. The signal of the azomethine HC=N proton is at 8.598 ppm. Thus, the appearance of
the azomethine proton signal and the disappearance of the –NH2 group resonance signal
both suggest condensation of the -HI and carbonyl components.11,15
TABLE IV. 1H-NMR data (/ppm) of the compounds
Compound
(OH) (NH2) (NH) (=CH) (phenyl
1) (phenyl2)
HI – 10.694 8.324 – 6.839–7.375 –
(s; 1H) (s; 1H) (m; 4H)
L 12.56 – 8.354 8.598 6.853–7.169 7.188–7.391
(s; 1H) (s; 1H) (s; 1H) (m; 4H) (m; 4H)
[CoLCl].Cl – – 8.250 8.581 6.850–7.195 7.180–7.398
(s; 1H) (s; 1H) (m; 4H) (m; 4H)
[CuLCl].Cl – – 8.256 8.580 6.849–7.196 7.181–7.399
(s; 1H) (s; 1H) (m; 4H) (m; 4H)
[NiLCl].Cl – – 8.255 8.581 6.849–7.195 7.180–7.399
(s; 1H) (s; 1H) (m; 4H) (m; 4H)
[ZnLCl].Cl – – 8.258 8.581 6.850–7.195 7.179–7.399
(s; 1H) (s; 1H) (m; 4H) (m; 4H)
1phenyl from the isatin part of the molecule; 2phenyl from the salicylaldehyde part of the molecule
Co(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 645
The main difference in the spectrum of complexes is the absence of the OH proton lo-
cated at 12.56 ppm in the free ligand. This indicates deprotonation of this group during co-
ordination with metallic ion.6,7 Also, a downfield shift of –NH and =CH group resonance
signal in the complex compounds is related with a decrease of the electron density and
deshielding of both protons, as a result of the participation of the adjacent C=O and C=N
groups in the coordination.13,14
The structural formula of the complexes shown in Fig. 1 is consistent with the above
mentioned data.
Antimicrobial activity
The experimental inhibition zones (mm) and the MIC values are shown in Table V.
As can be seen, all the compounds have different antibacterial activity in vitro against the
tested bacterial organisms.15,16
The results show that the bis-Schiff base exhibits the best activity against Staphylo-
coccus aureus.
TABLE V. Range of inhibition zones (mm) and MIC values (g cm–3) of the investigated compounds
Compound
E. coli P. mirabilis S. aureus E. group D B. anthracis
P.
aeruginosa
C. albicans
mm MIC mm MIC mm MIC mm MIC mm MIC mm MIC mm MIC
L 11 50–200 10 200–500 14 50–200 10 200–500 10 200–500 10 200–500 14 20–200
[CoLCl].Cl 22 <50 19 <50 22 <50 19 <50 23 <50 22 <50 26 <50
[CuLCl].Cl 22 <50 20 < 50 22 < 50 20 < 50 23 < 50 22 < 50 26 < 50
[NiLCl].Cl 21 50–200 19 <50 21 < 50 16 50–200 20 < 50 20 < 50 25 < 50
[ZnLCl].Cl 22 < 50 21 < 50 22 < 50 20 < 50 23 < 50 21 < 50 27 < 50
An influence of the central ion of the complexes in the antimicrobial activity against
the tested gram-positive and gram-negative organisms and yeast is evident. The results also
show that the complexes have an enhanced activity compared to the ligand itself. This is
646 KONSTANTINOVI] et al.
Fig. 1. The structure of the coordination compounds.
especially shown against Candida albicans. The metal activity decreases in the order Zn 
Cu > Co > Ni.
Acknowledgments: This work was supported by the Ministry of Science, Technologies and Develop-
ment of the Republic of Serbia.
IZVOD
SINTEZAIKARAKTERIZACIJACo(II),Ni(II),Cu(II)I Zn(II)KOMPLEKSASA
3-SALICILIDENHIDRAZONO-2-INDOLINONOM
SANDRAS. KONSTANTINOVI]1, BLAGAS. RADOVANOVI]2,@IVOJINCAKI]3 iVESNAVASI]4
1Tehnolo{kifakultet, BulevarOslobo|ewa 124, 16000 Leskovac, 2Prirodno-matemati~kifakultet,Odsek za
hemiju, ]irila iMetodija 2, 18000Ni{, 3Zavod za za{titu zdravqa, 16000 Leskovac i 4INNVin~a, 11000
Beograd
Sintetisani su kompleksiCo(II),Ni(II),Cu(II)iZn(II) sa 3-salicilidenhidrazono-2-indo-
linonom. Izolovani kompleksi su okarakterisani elementalnom mikroanalizom, merewem
molarne provodqivosti, magnetne susceptibilnosti, AA, FTIR, UV/VIS i 1H-NMR spektro-
skopskim metodama. Utvr|ena je kvadratno-planarna geometrija za Ni(II) i Cu(II), kao i
tetraedarska geometrija za Co(II) i Zn(II) komplekse. Sintetisanim jediwewima je ispitana
biolo{ka aktivnost u odnosu na Staphylococcus aureus, Enterococcus D, Proteus mirabilis, Esche-
richia coli, Bacillus anthracis, Pseudomonas aeruginosa i Candida albicans.
(Primqeno 3. decembra 2002, revidirano 16. aprila 2003)
REFERENCES
1. J. F. da Silva, S. J. Garden, A. C. Pinto, J. Braz. Chem. Soc. 12 (2000) 3
2. N. M. Samus, T. A. Burdenko, V. V. Gylka, V. I. Tsapkov, J. Chem. Pharma. 12 (1994) 40
3. V. I. Tsapkov, T. Mianperem, N. M. Samus, Russ. Gen. Chem. 65 (1995) 320
4. B. C. Stoj~eva Radovanovi}, S. S. Andjelkovi}, J. Serb. Chem. Soc. 63 (1998) 379
5. B. C. Stoj~eva Radovanovi}, S. S. Andjelkovi}, Analytical Laboratory 6 (1997) 190
6. S. O. Podunavac-Kuzmanovi}, V. M. Leovac, N. U. Peri{i}-Janji}, J. Rogan, G. Bala{, J. Serb. Chem. Soc.
64 (1999) 381
7. A. Z. El-Sonbati, Spectroscopy Lett. 30 (1997) 459
8. A. B. P. Lever, Inorganic Electronic Spectroscopy, Elsevier, Amsterdam, 1984
9. K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, Wiley, New
York, 1986
10. A. Z. El-Sonbati, A. A. El-Bindary, Polish J. Chem. 74 (2002) 621
11. J. Csaszar, J. Moway, O. Herceczeg, Acta Phys. Chem. 31 (1988) 717
12. F. A. Cotton, G. Wilkinson, Advanced Inorganic Chemistry, Wiley, New York, 1989
13. J. M. Daw, W. Henderson, B. K. Nicholson, J. Chem. Soc. Dalton Trans. 45 (1997) 87
14. A. M. Hassaan, M. A. Khalifa, A. K. Shehata, Bull. Soc. Chim. Belg. 104 (1995) 121
15. N. C. Kasuga, K. Sekino, C. Koumo, N. Shimada, M. Ishikawa, K. Nomiya, J. Inorg. Biochem.84 (2001) 55
16. K. Nomiya, K. Tsuda, T. Sudoh, M. Oda, J. Inorg. Biochem. 68 (1997) 39
17. L. Larabi, Y. Hared, A. Reguig, M. Mostafa, J. Serb. Chem. Soc. 68 (2003) 85.
Co(II), Ni(II), Cu(II) and Zn(II) COMPLEXES 647


http://vinar.vin.bg.ac.rs//bitstream/id/12289/2667.pdf

Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3-salicylidenehydrazono-2-indolinone

Abstract

Similar works

Full text

Available Versions

Crossref

Directory of Open Access Journals

Repository of the Vinča Nuclear Institute (VinaR)

VinaR - Repository of the Vinča Institute of Nuclear Sciences