Synthesis, characterization, antimicrobial, and DNA cleavage studies of metal complexes of coumarin Schiff bases

Abstract

Co(II), Ni(II), Cu(II), and Zn(II) complexes of the Schiff bases formed by the condensation of 8-formyl-7-hydroxy-4-methyl-coumarin with 3-amino-pyridine (L 1 ) and 3-amino-2-chloro-pyridine (L 2 ) are synthesized and characterized by various physico-chemical methods. The FAB-mass spectra of the ligand L 1 and its Zn(II) complex are reported herewith. Thermal studies with Co(II) and Ni(II) complexes of both the ligands L 1 and L 2 are also reported. From the above studies, it is concluded that the ligand L 1 acts as a bidentate ligand coordinating through azomethine nitrogen and phenolic oxygen of coumarin moiety via deprotonation, and ligand L 2 acts as a tridentate ligand coordinating through azomethine nitrogen, phenolic oxygen of coumarin, and chlorine of pyridine moiety. All the complexes showed an octahedral geometry with a slight distortion in Cu(II) complexes. The fluorescence studies are carried out for ligand L 1 with its Co(II), Ni(II), Cu(II), and Zn(II) complexes. The ligands and the complexes were screened for antibacterial and antifungal activities in vitro. The antitubercular activities are carried out by middle Brook method for all the compounds. The MIC values, cytotoxicity properties, and DNA cleavage studies are carried out for most active ligand L 2 , Co(II), and Cu(II) complexes.

Ag(I) and Zn(II) isonicotinate complexes: design, characterization, antimicrobial effect, and CT-DNA binding studies

“…Three ligand approaches are suggested [19][20][21][22]: transporters, which provide metal transport to infection, carriers which provide metal transport and its gradual delivery, multifunctional ligands, that can act as transporters, carriers and antibiotics or analgetics simultaneously.…”

SYNTHESIS, SPECTROSCOPIC, ANTICANCER, ANTIMICROBIAL AND ANTIOXIDANT STUDIES OF HOMO-BINUCLEAR Cu(II), Co(II), Ni(II) AND Mn(II) COMPLEXES WITH POLYDENTATE SCHIFF BASE LIGAND.

“…(fig.7). There are several reports were also cited for Co(II) and Cu(II) complexes showing better bioactivities [29]. Moreover, the heterocyclic Schiff bases having the different functional group to interact with nucleoside bases with greater tendency even after complexation with metal ions.…”

Synthesis, characterization and biological activity of Cu(II), Zn(II) and Re(I) complexes derived from S-benzyldithiocarbazate and 3-acetylcoumarin

“…Moreover, previously reported coumarin Schiff bases and their metal complexes were shown to exhibit outstanding luminescence (Datta et al 2011) which may be advantageous for application of related compounds as probes. Other studies revealed that the coumarin derivatives interact strongly with DNA and can cause DNA cleavage (Phaniband et al 2011;Kulkarni et al 2009). …”

“…Another example involves quinoline with 4(N,N)-dimethylthiosemicarbazone which produced a novel water-soluble sulphur-bridged binuclear copper(II) complex (Senthil Raja et al 2011). Coumarin derivatives, such as 3-acetylcoumarin opted for in this work, are attractive because of their wide variety of antioxidant, antibacterial, antifungal and cytotoxic activities (Datta et al 2011;Bagihalli et al 2008;Phaniband et al 2011;Kulkarni et al 2009;Creaven et al 2009). Moreover, previously reported coumarin Schiff bases and their metal complexes were shown to exhibit outstanding luminescence (Datta et al 2011) which may be advantageous for application of related compounds as probes.…”