Metal chelation ability of Protocatechuic acid anion with 210Po84; a theoretical insight

Complexation of 210Po84 with Protocatechuic acid (PCA) anion in various solvents was investigated using the DFT method employed at the B3LYP-GD3/6–311++G(2d,2p)/SDD level of theory. PCA is a secondary metabolite and pharmacologically important compound containing metal-chelating sites. The deprotonated form of PCA interacts with Po2+ and Po4+ ions producing [ML] and [ML]2+ complexes. The structural features and binding energy indicate the higher stability of [ML]2+ complexes. The topology analysis reveals the partially covalent electrostatic interaction between the ligand oxygen atoms and the metal ions. The solvent effect decreases binding energy as solvent polarity increases. The λmax value of PCA and [ML] complexes appear in the UVC wavelength range, whereas that of [ML]2+ complexes appears in the visible region. The solvent effect causes a bathochromic shift in PCA, [ML], and [ML]2+ complexes. Chelation of deprotonated PCA with 210Po84 indicates that it can be used as a bio-indicator or decontaminant of 210Po84.