Some five- and six-coordinated di- and tri- n-butyl tin(IV) complexes of the type Bu 2SnL, Bu 2SnL 2 and Bu 3SnL (where L is the anion of a monofunctional bidentate or bifunctional tridentate Schiff base) have been synthesized and characterised on the basis of microanalyses, molecular weight determinations, IR, NMR ( 1H, 13C, 119Sn) and 119Sn Mössbauer spectroscopy. These complexes are highly active towards bacteria.