Extended two-dimensional networks adsorbed on surfaces have attracted attention for applications in catalysis and nanotechnology. Traditionally, research has focused on sheet-like polymers such as graphene and boron nitride atop metals and metal oxides using computational and surface science techniques. More recently, however, it was demonstrated that ordered networks of monolayer thickness can also be formed on the surface of liquid water by using metal ions, e.g. Zn2+, to bind together multidentate ligand molecules. This presents a promising route towards producing atomically defined free-standing monolayers with chemical functionality. As such networks are challenging to characterize, computational methods can provide valuable insight into their formation and structure.In this contribution we present large-scale ab-initio molecular dynamics (MD) simulations of the formation of a network of tris-terpyridine-derived molecules (TTPB, Fig. 1a) on a water surface. In particular, we focus on the structure and dynamics of the molecule on the surface, the mechanism of Zn2+ion insertion from the solution and the subsequent linking of molecules into aggregates (Fig. 1b-d). We employ advanced MD methods to quantify the free energy surface of the involved processes. Our results provide detailed insight into on-surface and subsurface diffusion in this system and chemical reactions of TTPB on the surface of water.Figure 1: (a) Structure of the TTPB molecule (b-d) Schematic view of TTPB aggregation into a network atop water upon Zn2+uptake from solution.

Ab-initio simulation of 2D networks on the surface of water

248th National Meeting (2014)

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