Synthesis, structural investigation and biological application of new mono- and binuclear cobalt (II) mixed-ligand complexes containing 1,10-phenanthroline, acetamide and ethylenediamine

  • Getinet Tamiru
  • Atakilt Abebe
  • Moges Abebe
  • Misganaw Liyew
Keywords: Mixed mono- and binuclear cobalt (II) complex, Bisintercalation, Spectroscopic studies, Antibacterial activity.


The intensive use of antibiotics has led to an increase of drug resistant bacteria against known antibiotics. To overcome the alarming problem of microbial resistance to antibiotics, the discovery of novel active compounds against new targets is a matter of urgency. Based on this, we report three new mixed ligand complexes of cobalt (II)viz. mononuclear ([Co(phen)2(Act)(H2O)]Cl2.H2O and [Co(phen)2(Act)(en)]Cl2), and binuclear [Co2(phen)4(Act)2(en)]Cl4 which were synthesized from CoCl2.6H2O, 1,10-phenanthroline monohydrate, acetamide and ethylenediamine. These complexes were characterized using spectroscopic (ESI-MS, ICP-OES, FT-IR, and UV-Vis), chloride determination as well as melting point and conductance measurement. Invitro antibacterial activity was also tested on two Gram positive (Staphylococcus aureus, Streptococcus pyogenes) and two Gram negative (Escherichia coli and Klebsiella pneumoniae) bacteria using disc diffusion method. The complexes performed well even against the Gram-negative bacteria. The antibacterial result was found comparable with the commercial drug Gentamicin even at lower concentration of complexes. Thus, the synthesized complexes may be considered as potential antibacterial agents after passing cytotoxicity testing.


Atakilt Abebe and Tizazu Hailemariam (2016). Synthesis and assessment of antibacterial activities of ruthenium (III) mixed ligand complexes containing 1, 10-phenanthroline and guanide. Bioinorganic Chemistry and Applications,

Atakilt Abebe and Getinet Tamiru (2018). A hexacationic coordination compound from Co(II) and a cationic ligand derived from 4,4ʹ-bipyridine: Synthesis, characterization and investigation for biological application. Cogent Chemistry 4(1): 1564162.

Al-Resayes, S.I., Shakir, M., Shahid, N., Azam, M and Khan, A.U. (2016). Synthesis, spectroscopic characterization and in vitro antimicrobial studies of Schiff base ligand, H2L derived from glyoxalic acid and 1, 8-diaminonaphthalene and its Co (II), Ni (II), Cu (II) and Zn (II) complexes. Arabian Journal of Chemistry 9(3): 335-343.

Anjaneyulu, Y and Rao, R.P. (1986). Synthesis and antimicrobial studies of some metal complexes. Synthesis and Reactivity in Inorganic and Metal-Organic Chemistry 16: 257-261.

Atkins, P.W. (1994). Physical Chemistry, Oxford University Press, Oxford, UK, 5th edition.

Bencini, A and Lippolis, V. (2010). 1, 10-Phenanthroline: a versatile building block for the construction of ligands for various purposes. Coordination Chemistry Reviews 254(17-18): 2096-2180.

Bharathi Krishnan, R.V. (2016). Synthesis, characterization and study of biological applications of piperazine dithiocarbamate bridged homo binuclear mixed ligand complexes of Co (II) with amino acids. IOSR Journal of Applied Chemistry 9(6): 72-76.

Chandraleka, S., Ramya, K., Chandramohan, G., Dhanasekaran, D., Priyadharshini, A and Panneerselvam, A. (2014). Antimicrobial mechanism of copper (II) 1, 10-phenanthroline and 2, 2′-bipyridyl complex on bacterial and fungal pathogens. Journal of Saudi Chemical Society 18(6): 953-962.

Chang, E.L., Simmers, C and Knight, D.A. (2010). Cobalt complexes as antiviral and antibacterial agents. Pharmaceuticals 3(6): 1711-1728.

El-Reash, Y.G.A., Zaky, R and Yaseen, M.A. (2016). 2-(2-(2-Hydroxybenzyliden) hydrazinyl)-2-oxo-n-(pyridine-2-yl) acetamide complexes: synthesis, characterization and biological studies. Chemical Sciences Journal 7: 145.

Feng, G., Shi, Y., Zhang, L., Shi, R., Huang, W and Wang, R. (2017). Air-oxidation from sulfur to sulfone-bridged Schiff-base macrocyclic complexes showing enhanced antimicrobial activities. Scientific Reports 7(1): 15881.

Gao, Y., van Belkum, M. J and Stiles, M.E. (1999). The outer membrane of gram-negative bacteria inhibits antibacterial activity of brochocin-C. Applied and Environmental Microbiology 65(10): 4329-4333.

Ghatole, A.M., Lanjewar, K.R and Gaidhane, M.K. (2012). Syntheses, characterization, antimicrobial activity of Copper (II), Zinc (II) and Cobalt (II) complexes of the bi-dented substituted 2-((E)-2-((2-chloro-6-ethoxyquinolin-3-yl) methyleneamino) thiazol-4-yl) phenol having ON donor sites. Journal of Pharmacy Research 5(5): 2758-2762.

Golkar, Z., Bagasra, O and Pace, D.G. (2014). Bacteriophage therapy: a potential solution for the antibiotic resistance crisis. The Journal of Infection in Developing Countries 8(2): 129-136.

Gull, Y., Rasool, N., Noreen, M., Altaf, A.A., Musharraf, S.G., Zubair, M., and Zia-Ul-Haq, M. (2016). Synthesis of N-(6-Arylbenzo [d] thiazole-2-acetamide derivatives and their biological activities: an experimental and computational approach. Molecules 21(3): 266.

Gurumoorthy, P., Ravichandran, J and Rahiman, A.K. (2014). Mixed-ligand binuclear copper (II) complex of 5-methylsalicylaldehyde and 2, 2′-bipyridyl: Synthesis, crystal structure, DNA binding and nuclease activity. Journal of Chemical Sciences 126(3): 783-792.

Hast, M.A., Fletcher, S., Cummings, C.G., Pusateri, E.E., Blaskovich, M.A., Rivas, K and Beese, L.S. (2009). Structural basis for binding and selectivity of antimalarial and anticancer ethylenediamine inhibitors to protein farnesyltransferase. Chemistry & Biology 16(2): 181-192.

Housecraft, C.E and Sharpe, A.G. (2005). Inorganic Chemistry, Pearson Education, England, UK, 2nd edition.

Iniama, G.E and Iorkpiligh, T. (2013). Synthesis, characterization and antimicrobial studies of Mn (II) Co (II) and Zn (II) Schiff base complexes derived from L-Arginine and 2-Hydroxy-1-Naphthaldehyde. International Journal of Science and Research 4(8): 979-982.

Kerridge, D.H. (1988). The chemistry of molten acetamide and acetamide complexes. Chemical Society Reviews 17: 181-227.

Khopkar, S.M. (1998). Basic concepts of analytical chemistry. New Age International.

Krishna, P.M., Shankara, B.S and Reddy, N.S. (2013). Synthesis, characterization, and biological studies of binuclear copper (II) complexes of (2E)-2-(2-Hydroxy-3-methoxybenzylidene)-4n-substituted hydrazinecarbothio- amides. International Journal of Inorganic Chemistry,

Li, B and Webster, T.J. (2018). Bacteria antibiotic resistance: New challenges and opportunities for implant‐associated orthopedic infections. Journal of Orthopaedic Research 36(1): 22-32.

Mahalakshmi, R and Raman, N. (2016). A therapeutic journey of mixed ligand complexes containing 1, 10-phenanthroline derivatives: a review. Chemistry 16: 1-6.

Nworie, F.S. (2016). Bis(salicylidene) ethylenediamine (salen) and bis (salicylidene) ethylenediamine-metal complexes: From structure to biological activity. Journal of Analytical & Pharmaceutical Research 3: 76-85.

Panda, N., Tripathy, S.K., Behera, N.K., Panda, A.K., & Das, P.K. (2015). Synthesis, spectroscopic and anti-microbial studies of binuclear Schiff base complexes derived from the ligand prepared from isoniazid and benzilmonohydrazone. International Journal of Innovative Science, Engineering & Technology 2(4): 783-795.

Pasdar, H., Foroughifar, N and Hedayati Saghavaz, B. (2015). Investigation into the antibacterial activity of metal complexes derived from substituted chromone in comparison with tetracycline, and cephradine as standard drugs against Escherichia coli and Staphylococcus aureus. Journal of Medical Microbiology and Infectious Diseases 3(3): 75-79.

Patel, M.N., Chhasatia, M.R and Gandhi, D.S. (2009). Interaction of drug based binuclear mixed-ligand complexes with DNA. Bioorganic & Medicinal Chemistry 17(15): 5648-5655.

Podunavac-Kuzmanović, S.O., Leovac, V.M and Cvetković, D.D. (2008). Antibacterial activity of cobalt (II) complexes with some benzimidazole derivatives. Journal of the Serbian Chemical Society 73(12): 1153-1160.

Rafique, S., Idrees, M., Nasim, A., Akbar, H and Athar, A. (2010). Transition metal complexes as potential therapeutic agents. Biotechnology and Molecular Biology Reviews 5(2): 38-45.

Refat, M.S., El-Deen, I.M., Zein, M.A., Adam, A.M.A and Kobeasy, M. I. (2013). Spectroscopic, structural and electrical conductivity studies of Co (II), Ni (II) and Cu (II) complexes derived from 4-acetylpyridine with thiosemicarbazide. International Journal of Electrochemical Science 8(7): 9894-9917.

Saha, S., Dhanasekaran, D., Chandraleka, S and Panneerselvam, A. (2009). Synthesis, characterization and antimicrobial activity of cobalt metal complex against multi drug resistant bacterial and fungal pathogens. Facta Universitatis-series: Physics, Chemistry and Technology 7(1): 73-80.

Shalash, A.M and Ali, H.I.A. (2017). Synthesis, crystallographic, spectroscopic studies and biological activity of new cobalt (II) complexes with bioactive mixed sulindac and nitrogen-donor ligands. Chemistry Central Journal 11(1): 40.

Stănilă, A., Braicu, C and Stănilă, S. (2011). Antibacterial activity of copper and cobalt amino acids complexes. Notulae Botanicae Horti Agrobotanici Cluj-Napoca 39(2): 124-129.

Getinet Tamiru Tigineh and Liu, L.K. (2014). Studies on mechanochemistry: solid coordination compounds from primary aromatic amines and cobalt (II) chloride hexahydrate. Journal of the Chinese Chemical Society 61(11): 1180-1187.

Tweedy, B.G. (1964). Plant extracts with metal ions as potential antimicrobial agents. Phytopathology 55: 910-914.

US Department of Health and Human Services. (2013). Antibiotic resistance threats in the United States, 2013. Centers for Disease Control and Prevention. Atlanta, GA, 114 p.

Ventola, C.L. (2015). The antibiotic resistance crisis: part 1: causes and threats. Pharmacy and Therapeutics 40(4): 277-283.

Warra, A.A. (2011). Transition metal complexes and their application in drugs and cosmetics-a Review. Journal of Chemical and Pharmaceutical Research 3(4): 951-958.

WHO (World Health Organization) (2012a). Promoting access to medical technologies and innovation: intersections between public health, intellectual property and trade. World Health Organization. Switzerland, 253 p.

WHO (World Health Organization) (2012b) The evolving threat of antimicrobial resistance: options for action. World Health Organization, Geneva, Switzerland, 125 p.

WHO (World Health Organization). (2017). WHO publishes list of bacteria for which new antibiotics are urgently needed. WHO: Geneva, Switzerland; 7 p.

WHO (World Health Organization). (2018). Antibiotic resistance; Geneva, Switzerland; 86.


Journal Identifiers

eISSN: 2312-6019
print ISSN: 1816-3378