Synthesis, spectral characterization, in vitro microbial and cytotoxic studies of lanthanum(III) and thorium(IV) complexes with 1,2,4-triazole Schiff bases

A series of metal complexes of La(III) and Th(IV) have been synthesized with newly derived biologically active ligands. These ligands were synthesized by the condensation of 3-substituted-4-amino-5-hydrazino-1,2,4-triazole with 8-formyl-7-hydroxy-4-methylcoumarin. The structure of the complexes has been proposed by elemental analyses, spectroscopic data i.e. i.r., H-1 nmr, Uv-Vis, FAB-mass and thermal studies. The elemental analyses of the complexes conform to the stoichiometry of the type [La(L)center dot 3H(2)O]center dot 2H(2)O and [Th(L)(NO3)center dot 2H(2)O]center dot 2H(2)O where (L = (LI-LIV)). All the complexes are soluble in DMF and DMSO and are non-electrolytes in DMF and DMSO. All these ligands and their complexes have also been screened for their antibacterial (Escherichia coli, Staphylococcus aureus, Staphylococcus pyogenes and Pseudomonas aeruginosa) and antifungal activities (Aspergillus niger, Aspergillus flavus and cladosporium) by the MIC method. The brine shrimp bioassay was also carried out to study their invitro cytotoxic properties.