Activity on Leishmania tropica of metal complexes with NNOO tetradentate Schiff base ligand: Kinetic and thermodynamic studies from TG-DTA analysis

In the search for antileishmanial drug,tetradentate schiff base ligand 2-{(e)-[(2-{[(z)-(2-hydroxyphenyl)methylidene]amino}phenyl)imino]methyl}phenol (h2l) was reacted with transition metal ions to yield the complexes of the composition ml [where m = co (ii),ni (ii),cu (ii),& zn (ii)]. the copper based compound 3 (ic50 = 5.857 μm) showed activities even higher than the standard drug. tg and dta analyses under static air in the temperature range 30-1000 °c were also observed for all the compounds. the tg-dta analyses and the subsequent themodynamic and kinetic parameters calculated using the tg-dta curves,have potential relevance for the biological activities. horowitz-metzger method was applied for calculating the activation energies and order of pyrolysis. thermodynamic parameters like δs∗,δh∗ and δg∗ were subsequently calculated using the corresponding expressions. the order of decreasing thermal stability and decreasing activation energy follow the orders ni(ii) >co(ii) >zn(ii) >cu(ii) and e∗ cu>e∗ co>e∗ ni>e∗ zn,respectively.