Synthesis, characterization, DNA cleavage and in vitro antimicrobial studies of La(III), Th(IV) and VO(IV) complexes with Schiff bases of coumarin derivatives

Physicochemical studies and biological activity of mixed ligand complexes involving bivalent transition metals with a novel Schiff base and glycine as a representative amino acid

“…This band is absent in the spectra of metal(II) complexes, indicating coordination through the deprotonated phenolic OH group [35]. Moreover, it was evidenced by the shift in position of νCO (aromatic carbon and phenolic oxygen) at 1319 cm -1 [36] to the lower frequency region in the spectra of complexes [37]. However, the strong band observed at 1675 cm -1 in the free ATS ligand due to azomehtine group vibration is shifted towards lower frequencies in the complexes by (28-37 cm -1 ), suggesting that azomethine group is involved in coordination [38,39].…”

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.…”

Lanthanide(III) Complexes Incorporating Tridentate ONO-Donor Pyrazolone Ligand: Synthesis, Characterization, Fluorescence and Antimicrobial Studies

“…The higher activity of the complexes compared to free ligand may be attributed to chelation which reduces polarity of the metal ion by partial sharing of the positive charge with donor atoms of the ligand. This increases the lipophilic character of the metal chelates which favours the penetration into the lipid membrane of the cell wall of microorganism, thereby raising the activity of the complex and restricts further growth of the organism [46,47]. Higher activity observed against the Gram-negative bacteria can be explained by considering the effect on lipopolysaccharide (LPS), a major component of the surface of Gram-negative bacteria.…”