Synthesis, characterization and antimicrobial activity of Schiff base Ce(III) complexes

Some novel complexes of Ce(III) Schiff base of type [Ce(III)(Ln) 2 (NO 3 ) 2 ]NO 3 .xH 2 O [where Ln = ligand]2-(2,3-dihydro-1H-indolo[2,3-b] phenazin-4(5H)ylidene)hydrazinecarbothio amide (L 1 ), 3-(ethoxymethylene)-2,3-dihydro-1H-indolo[2,3-b]phenazin-4(5H)-ylidene)hydrazinecarbothioamide (L 2 ), (Z)-3-benzylidene-2,3-dihydro-1H-indolo[2,3-b]phenazin-4(5H)ylidene)hydrazine carbothioamide (L 3 ) have been investigated. The nature of bonding and structure of these complexes have been deduced from elemental analysis, molar conductance, magnetic measurements, thermogravimetric, FT-IR, UV-Vis, 1 H NMR, XRD and SEM studies. These studies revealed that the Ce(III) coordinated by eight donor atoms in all the complexes. Free radical scavenging activity was determined according to the elimination of radicals from 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H 2 O 2 . The ability of these compounds to inhibit the growth of pathogenic organisms Bacillus subtilis, Staplococcus aureus (as gram positive bacteria), Escherichia coli (as gram negative bacteria) and Candida tropicalis and Aspergillus niger (as fungal species) were compared to known antibiotics amoxicillin. The complexes are more potent than ligands as antimicrobial and antioxidant agent.