Synthesis of heteroleptic pentavalent antimonials bearing heterocyclic cinnamate moieties and their biological studies

Abstract

Abstract In the search of new drugs with high therapeutic efficacy, antimony (V) dicarboxylates bearing cinnamate moieties with general formula [SbR3(O2CR′)2] have been synthesized and characterized by spectroscopic techniques like FTIR, multinuclear (1H and 13C) NMR and single crystal X-ray diffraction. The organic moieties (R) in the complexes are phenyl and p-tolyl while the carboxylates are heterocyclic acrylates. In the crystal structure of [Sb(phenyl)3(O2CC2H2C4H3O)2] (1), [Sb(phenyl)3(O2CC2H2C4H3S)2] (3), [Sb(p-tolyl)3(O2CC2H2C4H3S)2] (5) and [Sb(p-tolyl)3(O2CC2H2C4H2O(CH3))2] (6), antimony was found to adopt a distorted trigonal bipyramidal geometry and was monomeric with phenyl or p-tolyl groups at equatorial and carboxylate ligands at axial positions. Furthermore, biological activities of carboxylates and their corresponding complexes were conducted including antileishmanial activity (against Leishmania tropica KWH23 parasite), anticancer (against HepG2 cell line), antibacterial (against Staphylococcus aureus, E. coli, P. aeruginosa and K. pneumoniae) and α-amylase inhibition potentials. Results show that compounds (4), (5) and (6) are significantly cytotoxic against cancer cells (median inhibitory concentration (IC50): 7.44, 4.61, 5.0 µg/mL respectively) and leishmania parasite (IC50: 1.75, 0.03 and 0.02 µg/mL respectively). Results of biological activities suggest these complexes as attractive therapeutic agents for further in vivo studies except α-amylase inhibition.