The necessity in heavy metal ion reduction to meet stricter environmental requirements in wastewater treatment, nuclear fuel recycle and their selective recoveries has led to the increasingly attractive development of selective reagents. Knowledge about complexation mechanism of metal ions is essential to design new functional polymer with much higher adsorption efficiency and specificity. Traditional ligand design mostly relies on the HASB principle, but the presence of non-ion-binding moieties might also greatly promote or disrupt the resulting metal bond strengths. Our work shows that introduction of additional hydroxyl group next to the neutral phosphate ligand (P=O) changes its polarizability, leads to significantly different metal ion affinity. Little Pb(II), Cu(II), Cd(II) are adsorbed on neutral phosphonate resin at pH 2, while their complexation is greatly enhanced with pentaerythritol resin phosphorylated with diethylchlorophosphate. Uranium(VI) adsorption at low acid solution proceeds through a coordination process and changes to ion exchange at high acid concentration. The unphosphorylated polyol resins have little metal ion affinity. It is clear that the metal ion complexation is dependent on both ion binding ligands (phosphoryl oxygen) and non-binding ligands (hydroxyl).