Ionic Sal-SG Schiff bases as new synergetic chemotherapeutic candidates: synthesis, metalation with Pd(II) and in vitro pharmacological evaluation

A series of novel N-(salicylidene)-sulfaguanidines (Sal-SG) bearing ionic liquid (IL) terminals (ILSSGH, 4a-f) have been synthesized by Schiff base condensation of IL-functionalized salicylaldehydes (ILSal, 3a-g) and sulfaguanidine (SG). Metalation trials of these ionic Schiff bases with palladium(II) chloride affords the corresponding Pd(II) complexes, [Pd(II)(ILSSG)Cl(H2O)] (5a-g). Further, the antimicrobial profiles of the new compounds against a set of common pathogens have been described. Zone of inhibition (ZOI) and minimal inhibitory concentration (MIC) values revealed that most of the new compounds exhibited significant antibacterial and potential inhibitory activity against Staphylococcus aureus (S. aureus), and this activity is modulated by substituents attached to the ionic liquid core as well as the counter-ion.