Binding of periodate by non–covalent interaction: Synthesis, characterization, single crystal structure determination, antibacterial and anticancer studies of [Co(bpy)2CO3].IO4

Abstract

The facile and effective synthesis of novel cobalt (III) complex salt of composition [Co(bpy)2CO3].IO4 (where bpy=2,2’-bipyridine, IO4= periodate) was performed in aqueous medium at room temperature. The complex was characterized with wide range of analytical and spectroscopic tools such as CHN, FT-IR, UV–Vis and 1H NMR. The complex salt crystallizes in triclinic space group (P-1) with a=7.17687(12), b= 10.8056(2), c= 14.3822(3)Å, α=83.4356(17)°, β=85.3108(15)°, γ=86.2535(16)°, V=1102.56(4)Å3 and Z=2. The single-crystal X-ray diffraction studies revealed that the complex is six coordinated with the inner coordination sphere of the metal ion comprising of one carbonate and two 2,2’-bipyridine moieties. The crystal has distorted octahedral geometry with hydrogen bonding interactions [C‒Hδ+···Oanionδ−] existing in the crystal lattice. The thermogravimetric studies were performed to further support the coordination structure of the complex. In addition, the complex was tested for in vitro antibacterial activity against Gram-positive (S. aureus) and Gram-negative bacteria (E.coli and P. aeruginosa). The complex showed significant activity against all three bacteria tested, however S. aureus was found to be more sensitive to it, with MIC of 400 µM. Further, the complex showed good anti-cancer potential as it was able to reduce the viability of HeLa cells in a concentration dependent manner with IC50 value corresponding to 60 µM.