New Tetra-dentate Schiff Base Ligand N2O2 and Its Complexes with Some of Metal Ions: Preparation, Identification, and Studying Their Enzymatic and Biological Activities

Main Article Content

Khitam J. Nabhan
Amer S. Mahdi
Basim H. Al-Zaidi
Ahmad H. Ismail
Zaizafoone N. Nasif


In present work, new tetra-dentate ligand, titled 3,5-bis ((E)-5-Bromo-2-hydroxy benzylidene amino) benzoic acid (H3L), was prepared via an acid-catalyzed condensation process. New four metallic ligand complexes with Co(II), Ni(II), Cu(II) and Zn(II) ions, were also prepared from the refluxing of equivalent moles. Ligand's structure and its complexes; were confirmed by numerous characterization methods, including Ultraviolet-Visible, Infrared, Mass Spectrometer, 1H and 13C Nuclear Magnetic Resonance spectra, atomic absorption, magnetic moments, and molar conductivity measurements. The results of the spectroscopic analyzes proved that the prepared ligand acts as tetradentate bi-ionic ligand and it was bonded to the metal ions by two nitrogen atoms of the two azomethine groups and by two oxygen atoms of the two phenolic hydroxyl groups after losing their two protons. Octahedral structure proposed to all prepared complexes. The (anti-bacterial) and (anti-fungal) activities of these compound were screened against (E. coli, S. aureus, Klebsiella spp., S. epidermidis,), and (Candida albicans). The results indicated that these compounds have moderated inhibition behavior. The activity of the prepared compounds against Acetyl Choline Esterase Enzyme (AChE) have also studied and the obtained data indicated the presence of different inhibition behavior.


Download data is not yet available.

Article Details

How to Cite
Nabhan KJ, Mahdi AS, Al-Zaidi BH, Ismail AH, Nasif ZN. New Tetra-dentate Schiff Base Ligand N2O2 and Its Complexes with Some of Metal Ions: Preparation, Identification, and Studying Their Enzymatic and Biological Activities. Baghdad Sci.J [Internet]. [cited 2021Dec.4];19(1):0155. Available from:
Author Biography

Basim H. Al-Zaidi, Department of Chemistry, College of Science, Mustansiriyah University, Baghdad, Iraq.




Moamen SR, Sabry AE, Deo NK, Ahmed SA. Syntheses and characterization of Ru(III) with chelating containing ONNO donor quadridentate Schiff bases. Spectrochim. Acta A. 2008; (70): 898–906.

Basim HA, Mohammed MH, Ahmad HI. New complexes of chelating Schiff base: Synthesis, spectral investigation, antimicrobial, and thermal behavior studies. J. Appl. Pharm. Sci. 2019; 9(04): 045-057.

Shelke VA, Jadhav SM, Patharkar VR, Shankarwar SG, Munde AS, Chondhekar TK. Synthesis, spectroscopic characterization and thermal studies of some rare earth metal complexes of unsymmetrical tetradentate Schiff base ligand. Arab. J. Chem.. 2012; (5): 501–507.

Santos IC, Vilas-Boas M, Piedade MFM, Freire C, Duarte MT, De Castro B. Electrochemical and X-ray studies of Nickel(II) Schiff base complexes derived from salicylaldehyde. Structural effects of bridge substituents on the stabilisation of the +3 oxidation state. Polyhedron. 2000; (19): 655-664.

Basim HA, Asia HA, Fadhel RH, Ali NN. Synthesis, Characterization and Studying the Enzyme Activity of New Benzothiazole Schiff Base Ligand (HL) and Its Complexes with Some of Metal Ions. Ibn Al-Haitham Jour. for Pure & Appl. Sci. 2017; 30(2): 125-140.

Thomas R, Roger K, Sebastian F, Juliane M, Peter K, Michael P. et al. Systematic comparison of the structure of homoleptic tetradentate N2O2-type Schiff base complexes of tetravalent f-elements (M(IV) = Ce, Th, U, Np, and Pu) in solid state and in solution. Dalton Trans. 2020;49: 17559-17570.

Chizoba IE, Oguejiofo TU, Pius OU, Nkechi NU. Complex Formation and Extraction Studies of N,N′-Bis (salicylidene)-3,5-diaminobenzoic Acid on Hg(II) and Ag(I). Chem. Sci. Trans. 2013; 2(4):1118-1125.

Wail A, Farouk K, Mohamad KC. The synthesis of N2O2-Schiff base ligand and bulk liquid membrane transport of Cu2+. Arab. J. Chem. 2016; (9): 626–632.

Mehrorang G, Javad T, Morteza M, Mahdi NB, Batool S. Highly selective and sensitive determination of copper ion by two novel optical sensors. Arab. J. Chem. 2017; (10): S2319–S2326.

Ali O, Bouzid K, Larbi Z. Elaboration of modified poly(NiII-DHS) films as electrodes by the electropolymerization of Ni(II)-[5,50-dihydroxysalen] onto indium tin oxide surface and study of their electrocatalytic behavior toward aliphatic alcohols. Arab. J. Chem. 2017; (10): 914–921.

Abbas A. S. Al-Hamdani and Rehab G. H. Transition Metal Complexes with Tridentate Ligand:

Preparation, Spectroscopic Characterization, Thermal

Analysis and Structural Studies. Baghdad Sci. J. 2016; 13(4): 770-781.

Agarwal U, Singh NP, Kumar A, Kumar K. Synthesis, Spectral Study and Antibacterial Activity of Asymmetrical Tetradentate Schiff Base Complexes. Rasayan J. Chem. 2020; 13(3): 1685 1691.

Singh NP, Kumar K, Kumar A, Agarwal U. Synthesis, Characterization and Antimicrobial Activity of Mn(II),Fe(II), Ni(II),Co(II) AND Zn(II) Complexes of Schiff Base Derived From 2,2- Dimethylpropane 1, 3-Diamine and 5-Chloro Isatin. Rasayan J. Chem. 2020; 13(1): 215-221.

Abhay NS, Netra PS, Chandra KS. In vitro antibacterial and antifungal activities of binuclear transition metal complexes of ONNO Schiff base and 5-methyl-2,6-pyrimidine-dione and their spectroscopic validation. Arab. J. Chem. 2016; (9): 48–6.

Preeti J, Vandna S, Sabir A, Vishwas T, Upendra S. Synthesis, characterization, molecular docking and biological activity of 5,6-bis-(4-fluoro-phenyl)- 3,4,7,8-tetraaza-bicyclo[8.3.1]tetradeca-1 (13),4,6,10(14),11-pentaene-2,9 dione and its transition metal complexes. J. Saudi Chem. Soc. 2018; (22): 546–557.

Panda J, Adhikari L, Pal A, Rout SS, Pattanaik S, Pradhan P. Antioxidant and Anti-microbial Activity Study of Synthesized Copper, Nickel and Zinc Metals Schiff Base Derivative of Salicylaldehyde. Rasayan J. Chem. 2020; 13(1): 556–561.

Kannan B, Periyasamy R, Govindan P, Periyasamy V, Sirichai A, Thayumanavan P. Evaluation of invitro a-amylase and a-glucosidase inhibitory potential of N2O2 schiff base Zn complex. Arab. J. Chem. 2017; (10): 732–738.

Ming-jin X, Ming-rong Z, Chun-Mei L, Yi J, Li-Hui G, Ling L, et al. Synthesis and characterization of oxidovanadium complexes as enzyme inhibitors targeting dipeptidyl peptidase IV. J. Inorg. Biochem. 2017; (175): 29-35.

Adnan A B, Hayam M A A, Yasser S A G, Alaa El-Din A B, Azza B. Synthesis and biological evaluation of some thiazolyl and thiadiazolyl derivatives of 1H-pyrazole as anti-inflammatory antimicrobial agents. Eur. J. Med. Chem. 2008; 43(3): 456-463.

Samina K T, Abhijit A Y, Ratnamala S B. Synthesis and characterization of a novel schiff base of 1,2-diaminopropane with substituted salicyaldehyde and its transition metal complexes: Single crystal structures and biological activities. J. Mol. Struct. 2018; 1152: 223-231.

Linus C, Laura ENA, Juan A, Michael CPW, Tim S, Michael PS. Tuning ligand electronics and peripheral substitution on cobalt salen complexes: structure and polymerisation activity. Dalton Trans. 2014; (43): 4295–4304.

Alekha KS, Yasobanta D, Sasmita P, Nibedita N, Prasanta R, Tungabidya M. Synthesis and structural studies of nickel complex supported by-ONNO-tetra dentate Schiff-base ligand: efficient catalysts for oxidation of phenol. IJMSA. 2013; 2(4): 136-145.

Kumar S P, Vijayaraj A, Vijayalakshmi L, Narayanan V. Electrochemical, Kinetic, Antimicrobial (MIC)

Studies of Acyclic Schiff-Base Nickel(II) Complexes. Chem. Sci. Trans. 2013; 2(S1): S225-S233.

Wan NWI, Mustaffa S. Symmetrical Palladium (II) N,N,O,O-Schiff Base Complex: Efficient Catalyst for Heck and Suzuki Reactions. Cryst. Struct. Theory Appl. 2012; (1): 25-29.

Mohamed IA. Synthesis, characterization and catechol oxidase biomimetic catalytic activity of Cobalt(II) and Copper(II) complexes containing N2O2 donor sets of imine ligands. Arab. J. Chem.. 2016; (9): S1297–S1306.

Ali C, Serhan U, Mehmet S. Synthesis and spectroscopic characterization of new tetradentate Schiff base and its coordination compounds of NOON donor atoms and their antibacterial and antifungal activity. J. Saudi Chem. Soc. 2010; (3): 103–113.

Dhrubajyoti M, Sourav D, Jayanta K B, Monojit M. Synthesis, structure, fluorescent property, and antibacterial activity of new Cd(II) metal complex based on multidentate Schiff base ligand N,N′-Bis(3-

methoxysalicylidenimino)-1,3-diaminopropane. J. Mol. Struct. 2017; 1134: 617-624.

Raymond JA, Jonathan JB, Lee G, Manuel P. H chemical shifts in NMR: Part 23,† the effect of dimethyl sulphoxide versus chloroform solvent on 1H chemical shifts. Magn. Reson. Chem. 2006; (44): 491–509.

Basim HA, Ahmed HI, Ali NN, Wessal K. Preparation, Characterization and Biological Activity of New Tridentate Imine-Oxime Ligand (H2L) and Its Metal Complexes. Asian J Chem. 2018; 30(5): 1157-1164.

Sayed MA, Zayed MA, Gehad GM. Synthesis and spectroscopic characterization of new tetradentate Schiff base and its coordination compounds of NOON donor atoms and their antibacterial and antifungal activity. Arab. J. Chem. 2010; 3(2): 103–113.

Robert MS, Francis XW, David JK. Spectrometric Identification of Organic Compounds, John Wiley & Sons, Inc, Hoboken, New Jersey, 7th ed., 2005.

Barbara M, Nina P, Nina L. Beyond the Simple Copper(II) Coordination Chemistry with Quinaldinate and Secondary Amines. Molecules. 2020; 25(7): 1573.

Kazuo N. Infrared and Raman Spectra of Inorganic and Coordination Compounds, John Wiley & Sons, Inc, Hoboken, New Jersey, 6th ed., 2009.

Ahmad HI, Basim HA, Ahmed NA, Nadir FH. Synthesis and characterization of novel thin films derived from pyrazole 3 one and its metal complex with bivalent nickel ion to improve solar cell efficiency. Chem. Pap. 2020; (74): 2069–2078.

Salam KS, Lekaa KA. Some Metal Ions Complexes Derived From Schiff Base Ligand with Anthranillic Acid: Preparation, Spectroscopic and Biological Studies. Baghdad Sci. J. 2020; 17(1): 99-105.

George LE, Courtney KD, Valentino A, Robert MF. A new and rapid colorimetric determination of acetylcholinesterase activity. Biochem. Pharmacol. 1961;7(2): 88-90.

Zaizafoon N. Kinetics for the Inhibition of Serum Acetylthiocholin Esterase Activity by Some Prepared Phenobarbital Derivatives. Int. J. Biochem. Res. Rev. 2015; 7(2): 100-111.

Işık M, Demir Y, Durgun M, Türkeş C, Necip A, Beydemir Ş. Molecular docking and investigation of 4-(benzylideneamino)- and 4-(benzylamino)-benzenesulfonamide derivatives as potent AChE inhibitors. Chem. Pap. 2020; 74: 1395–1405.

Ahmad M F, Samira S D, Alireza A. Synthesis and Acetylcholinesterase Inhibitory Evaluation of 4-(1,3-Dioxoisoindolin-2-yl)-N-Phenyl Benzamide Derivatives as Potential Anti-Alzheimer Agents. Iran J Pharm Res. 2016; 15(3): 313–320.

Catarina O, Donatella B, Fernando C, JoséT, Ricardo A, Tiago S. et al. Benzoic acid-derived nitrones: A new class of potential acetylcholinesterase inhibitors and neuroprotective agents. Eur. J. Med. Chem. 2019; (174): 116-129.