• Charity W. Dikio Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa
  • Ikechukwu P. Ejidike Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa
  • Fanyana M. Mtunzi Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa
  • Michael J. Klink Department of Biotechnology, Vaal University of Technology, Vanderbijlpark, 1911, South Africa
  • Ezekiel D. Dikio Department of Chemistry, Vaal University of Technology, Vanderbijlpark, 1911, South Africa


Objective: The study was focused on the synthesis and spectroscopic studies of metal acetylacetonates and their complexes using bidentate Schiff-base ligands (NO), evaluation of their in-vitro antibacterial potentials against pathogenic microorganism.

Methods: Acetylacetonate salts of Cobalt(II), Manganese(II) and Magnesium(II) were prepared by reacting their metal hydroxides with acetylacetone. The metal complexes of N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-nitrobenzohydrazide (HL1), N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-methoxybenzohydrazide (HL2) obtained from the condensation reaction of 4-(diethylamino)-2-hydroxybenzaldehyde and 4-nitrobenzohydrazide/ or 4-methoxybenzohydrazide. The synthesized compounds were characterized by fourier transform infrared spectroscopy (FT-IR), proton and carbon-13 nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA). The compounds were screened for their antimicrobial properties against a list of Gram-positive bacterial strains.

Results: The FT-IR spectra revealed that the Schiff bases acts as bidentate chelating ligand via nitrogen of the azomethine and phenolic oxygen atoms. NMR reveal the presence of azomethine (HC=N) and aromatic hydrogens at expected chemical shifts confirming the formation of the Schiff base ligands. Thermal decomposition behaviour was studied by thermogravimetry revealing stability up to 260 °C. The compounds were evaluated for their antibacterial potentials against Staphylococcus aureus and Enterococcus faecalis. The manganese acetylacetonato(N'-{(E)-[4-(diethylamino)-2-hydroxyphenyl]methylidene}-4-methoxybenzohydrazide: Mn(acac)(L2) exhibited antimicrobial activities against both Enterococcus faecalis and Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 398.0 μg/mL.

Conclusion: The prepared compounds showed no inhibition against the selected pathogenic microorganisms except for Mn(acac)(L2) Standard antibacterial compounds: ampicillin and ciprofloxacin were used as positive control. The antibacterial activity of the compound depends on the kind of substituent on the benzo hydrazide rings at the para position, thereby suggesting the compound as promising chemotherapeutic agents for further structural optimization.


Keywords: Metal acetylacetonates, Schiff base complexes, Spectroscopic studies, Thermal studies, Antibacterial


Download data is not yet available.


1. Iqbal J, Siddiqui R, Kazmi SU, Khan NA. A simple assay to screen antimicrobial compounds potentiating the activity of current antibiotics. Biomed Res Int 2013. http://dx.doi.org/ 10.1155/2013/927323
2. Ejidike IP, Ajibade PA. Transition metal complexes of symmetrical and asymmetrical schiff bases as antibacterial, antifungal, antioxidant, and anticancer agents: progress and prospects. Rev Inorg Chem 2015;35:191-224.
3. Kajal A, Bala S, Kamboj S, Sharma N, Saini V. Schiff bases: a versatile pharmacophore. J Catal 2013. http://dx.doi.org/ 10.1155/2013/893512
4. Parsaee Z, Mohammadi K. Synthesis, characterization, nano-sized binuclear nickel complexes, DFT calculations and antibacterial evaluation of new macrocyclic schiff base compounds. J Mol Struct 2017;1137:512-23.
5. Bartyzel A. Synthesis, crystal structure and characterization of Manganses(III) complex containing a tetradentate schiff base. J Coord Chem 2013;66:4292-303.
6. Upadhayay N. Synthesis, characterization and biological studies of some Thiocyanato-bridged bimetallic complexes containing Co(II), Cd(II), Hg(II) and N,N Bis(benzylidene)-1,2-phenylene-diamine schiff base. Chem Sci Trans 2013;2:455-60.
7. Bruckner C, Rettig SJ, Dolphin D. 2-PyrrolyLthiones as monoanionic bidentate N,S-chelators: Synthesis and molecular structure of 2-pyrrolthionnato complexes of Nickel(II), Cobalt(III), Mercury(II). Inorg Chem 2000;39:6100-6.
8. Muruganandam L, Kumar KK, Balasubramanian K. Synthesis, characterization, antibacterial, antifungal and anticancer studies of a new antimetabolite: N-[(Diphenylamino) methyl]acetamide and some of its inner transition metal chelates. Chem Sci Trans 2013;2:379-84.
9. Madhavi K, Sree Ramya G. Synthesis, antioxidant and anti-inflammatory activities of ethyl 2-(2-cyano-3-(substituted phenyl)acrylamido)-4,5-dimethylthiophene-3-carboxylates. Asian J Pharm Clin Res 2017;10:95-100.
10. Sahebalzamani S, Ghammamy S, Mehrani K, Salimi F. Synthesis, characterization and thermal analysis of Hg(II) complexes with hydrazide ligands. Chem Sin 2010;1:67-72.
11. Benabid S, Douadi T, Debab H, De Backer M, Sauvage F. Synthesis, spectroscopic, and electrochemical characterization of a schiff base: 4,4-bis[(4-diethylaminosalicylaldehyde)diphenyl methane]diimine and its complexes with copper(II), cobalt(II), and cadmium(II). Synth React Inorg Met Org Chem 2012;42:1-8.
12. Jamuna K, Naik BR, Sreenu B, Seshaiah K. Synthesis, characterization and antibacterial activity of Cu(II) and Fe(III) complexes of a new tridentate schiff base ligand. J Chem Pharm Res 2012;4:4275-82.
13. Kelode SR. Synthesis, characterization and antimicrobial activity Cr(III), Mn(III), Fe(III), VO(IV), Zr(IV) and UO2(VI) metal complexes derived from bidentate thiazole schiff base. J Chem Pharm Res 2013;5:100-3.
14. Ejidike IP, Ajibade PA. Synthesis, spectroscopic, antibacterial and free radical scavenging studies of Cu(II), Ni(II), Zn(II) and Co(II) complexes of 4,4'-{ethane-1,2-diylbis[nitrilo(1E)eth-1-yl-1-ylidene]}dibenzene-1,3-diol Schiff base. J Pharm Sci Res 2017;9:593-600.
15. Pouralimardan O, Anne-Christine C, Janiak C, Hosseinimonfared H. Hydrazone Schiff base manganese(II) complexes: Synthesis, crystal structure and catalytic reactivity. Inorg Chim Acta 2007;360:1599-608.
16. Onal Z, Yildirim I, Kandemirli F, Arslan T. Experimental and theoretical studies on the reactions of 1-amino-5-benzoyl-4-phenyl-1H-pyrimidine-2-one/-thione compounds with ethyl acetoacetate. J Struct Chem 2010;21:809-16.
17. Al-Shaalan NH. Synthesis, characterization and biological activities of Cu(II), Co(II), Mn(II), Fe(II), and UO2(VI) complexes with a new schiff base Hydrazone: O-Hydroxyacetophenone-7-chloro-4-quinoline Hydrazone. Molecules 2011;16:8629-45.
18. Abdel-Rahman LH, Ismail NM, Ismael M, Abu-Dief AM, Ahmed EA. Synthesis, characterization, DFT calculations and biological studies of Mn(II), Fe(II), Co(II) and Cd(II) complexes based on a tetradentate ONNO donor schiff base ligand. J Mol Struct 2017;1134:851-62.
19. Annapure SR. Synthesis and characterization of Ni(II), Cu(II) metal complexes of new tetradentate ligand derived from dehydroacetic acid. Int J Chemtech Res 2017;10:455-60.
20. Thakar AS, Joshi KT. Synthesis, characterization and antibacterial activity of Schiff bases and their metal complexes derived from 4-acyl-1-phenyl-3-methyl-2-pyrazolin-5-ones. J Chem 2010;7:1396-406.
21. Manjula B, Antony SA, Dhanaraj CJ. Synthesis, spectral characterization, and antimicrobial activities of Schiff base complexes derived from 4-Aminoantipyrine. ‎Spectrosc Lett 2014;47:518-26.
22. Makhijani RM, Barhate VD. Synthesis, characterization, and study of microbiological activity of some transition metal ion complexes with [N-(O-methoxy benzaldehyde)-2-aminophenol] (NOMBAP). Int J Curr Pharm Res 2014;6:26-30.
23. Budhwani S, Sharma S, Kalyane N. Synthesis of aryl (5-substituted benzofuran-2-yl) carbamate derivatives as antimicrobial agents. Asian J Pharm Clin Res 2017;10:377-81.
452 Views | 2217 Downloads
How to Cite
Dikio, C. W., I. P. Ejidike, F. M. Mtunzi, M. J. Klink, and E. D. Dikio. “HYDRAZIDE SCHIFF BASES OF ACETYLACETONATE METAL COMPLEXES: SYNTHESIS, SPECTROSCOPIC AND BIOLOGICAL STUDIES”. International Journal of Pharmacy and Pharmaceutical Sciences, Vol. 9, no. 12, Dec. 2017, pp. 257-6, doi:10.22159/ijpps.2017v9i12.22225.
Original Article(s)