The formation of metal clusters in solution and on biopolymers investigated by first‐principles molecular dynamics

Abstract

AbstractWe investigate the molecular mechanisms of platinum cluster nucleation and growth in solution and on biopolymers by means of first‐principles molecular dynamics. In contrast with a classical picture where clusters nucleate by aggregation of metallic Pt(0) atoms, we find that Pt–Pt bonds can form between dissolved Pt(II) complexes already after a single reduction step. Furthermore, we observe that small clusters grow by addition of unreduced PtCl2(H2O)2complexes, consistently with an autocatalytic growth mechanism. Moreover Pt(II) ions covalently bound to biopolymers are found to act as preferred nucleation sites for the formation of clusters. This is a consequence of the strong donor character of the organic ligands which induce the formation of stronger metal‐metal bonds than those obtained in solution. In fact, in metallization experiments we obtain a clean and purely heterogeneous metallization of single DNA molecules leading to thin and uniform Pt cluster chains extended over several microns.