Synthesis, structural characterization and anticancer activity of some new complexes of 6-amino-4-hydroxy-2-thiopyrimidine

New complexes of 6-amino-4-hydroxy-2-thiopyrimidine (Hahtp), [Zn(ahtp)2(H2O)2], [Zn(ahtp)2(PPh3)(H2O)], [Zn(Hahtp)(bpy)Cl2], [Pd(phen)(ahtp]Cl, [Pd(Hahtp)(PPh3)2]Cl2, [Ag(ahtp)(H2O)2], [Ag(ahtp)(PPh3)(H2O)], [Ag(ahtp)L] (L = bpy, phen), have been synthesized and characterized on the basis of spectral (IR, 1H-NMR, ESI-mass and UV–visible), elemental analysis, thermal and molar conductivity measurements. Three modes of chelations have been observed for Hahtp; as a neutral bidentate ligand through cyclic nitrogen and thione sulfur atoms, mononegative bidentate ligand through either the deprotonated cyclic nitrogen and thione sulfur atoms or the deprotonated hydroxy and cyclic nitrogen atoms; all forming four-membered chelating rings. The free Hahtp and its complexes, [Zn(ahtp)2(H2O)2], [Zn(Hahtp)2(PPh3)(H2O)], [Zn(Hahtp)(bpy)Cl2], [Pd(phen)(Hahtp]Cl and [Ag(Hahtp)(PPh3)(H2O)] have been tested against the human breast cancer MDA-MB231 cell line. The [Ag(ahtp)(PPh3)(H2O)] complex exhibits the highest efficacy with a mean IC50 value of 4.7 μM.