Studies on Metallic Complexes of [(E)-4-{(1-(2-hydroxyphenyl)-ethylidine amino}- 1, 2, 4-triazolidine, 3, 5-dithione]

Triazole Schiff bases play an important role as ligands in coordination chemistry1 and demonstrate substantial pharmacological and biological activities 2 .Specifically 1, 2, 4-triazole and its derivatives exhibit properties of antibacterial 3, antioxidant 4, anticonvulsant5, antifungal6, antiviral7, and antiinflammatory8 agents.Metal complexes of 1,2,4-triazole Schiff bases are used as biocides in controlling many harmful species of fungi that cause infectious diseases in plants and living organisms.Metals complexes of triazole derivatives are also used in stimulating plants growth9 .Based on the above, we pursued synthesis of substituted imino-1,2,4-triazole and its metal complexes.(E) -4-{(1-(2-hydroxyphenyl)-ethylidine amino}-1,2,4-triazolidine,3,5-dithione is multidentate chelating ligand and can exist as thione, thiol tautomer's as shown below.The ligand (LH2) containing mercapto group(>C=S) exists in thione tautomer in acidic medium(Ph6) but in basic medium it can get tautomerise to thiol form(>C-SH).The ligand has donor sites oxygen, nitrogen and sulphur as well and it is expected that it can form strong complexes with class 'a' and class' b' metals ions both.In present chapter I report the complexes of Cr(III),Fe(II),Iron(III),Mn(II),Ni(II),Cobalt(II),Zn(II) and Cd(II) II. EXPERIMENT A. Chromium (III) Complex [CrL(LH)]H2OAbout 0.01 gram mole of hydrated chromium (III) chloride[Cr(H2O)4Cl2]Cl.H2O was dissolved in aqueous methanol and treated with 0.021 gram mole of ligand (LH2) dissolved in 30 ml hot methanol.The mixed solution was refluxed on steam bath for half an hour by raising the pH of solution by adding a few drop triethylamine.The brownish yellow complex of chromium (III) separated gradually.The product was cooled and filtered on small Buckner funnel and was washed several time with aqueous methanol.The complex was dried in a desiccator and product was analysed.The analytical result of complex is recorded in Table A. B. Preparation of [Fe(LH)2]2H2O About 0.01 gram mole of Mohr's salt (NH4)2FeSO4.7H2Owas dissolved in aqueous methanol and treated with 0.021 gram mole of ligand (LH2) dissolved in 30 ml hot methanol.The mixed solution was refluxed on steam bath for half an hour by raising the pH of solution by adding a few drop triethylamine.The brownish yellow complex of Iron(II) separated gradually.The product was cooled and filtered on small Buckner funnel and was washed several time with aqueous methanol.The complex was dried in a desiccator and product was analysed.The analytical result of complex is recorded in Table A