Investigation of interaction between the Pt(II) ions and aminosilane-modified silica surface in heterogeneous system

Distribution diagram for the Pt(II) complexes with insoluble diamine ligand immobilized on amorphous silica surface. [Display omitted] •Stability constants and types of complexes in which the ligand is placed on silica surface.•UV–vis show strong interactions between Pt(II) and immobilized ligand on surface.•The potentiometric titration method for qualification of dynamic equilibrium in heterogeneous system. UV–vis spectroscopy measurements confirmed the reaction in heterogeneous system between Pt(II) ions and ethylenediamine type ligand, n-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, immobilized at the silica surface. The formation of complexes is a consequence of interaction between the amine groups from the ligand grafted onto SiO2 and ions of platinum. A potentiometric titration technique was to determine the stability constants of complexes of Pt(II) with immobilized insoluble ligand (SG-L), on the silica gel. The results show the formation of three surface complexes of the same type (PtHSG-L, Pt(HSG-L)2, PtSG-L) with SG-L ligand, in a wide range of pH for different Debye length. The concentration distribution of the complexes in a heterogeneous system is evaluated.