Antimicrobial and mutagenic properties of organotin(IV) complexes with isatin and N-alkylisatin bisthiocarbonohydrazones

A new series of ligands is synthesised starting from thiocarbonohydrazide and isatin (H(2)itc) or N-alkylisatin (methyl, H(2)mtc; butyl, H(2)btc; pentyl, H(2)ptc); the X-ray structure of H(2)mtc is discussed. The his imine ligands are reacted with diorganotin(IV) compounds, obtaining monometallic complexes. In order to establish unequivocally their coordination geometry, the X-ray structures of (C2H5)(2)Sn(Hmtc)Cl.THF (THF, tetrahydrofuran) and (C6H5)Sn(Hptc)Cl-2 are determined. In (C2H5)(2)Sn(Hmtc)Cl.THF, the ligand results monodeprotonated and, essentially, monodentate through the Sulphur atom, while in (C6H5)Sn(Hptc)Cl-2 the ligand is still monodeprotonated but SNO tridentate. The organotin(IV) complexes of isatin and N-methylisatin exhibit good antibacterial activity, better than that of the corresponding N-butyl and N-pentylisatin derivatives. Gram positive bacteria are the most sensitive microorganisms. No growth inhibition of fungi is detected up to the concentration of 100 mug/ml. H(2)mtc shows mutagenic activity with and without metabolic activation, whereas no mutagenicity is found for its organotin complexes and for the other compounds. (C) 2004 Elsevier Inc. All rights reserved.