Self-Assembly at the Air−Water Interface. In-Situ Preparation of Thin Films of Metal Ion Grid Architectures

Abstract

Oriented crystalline films, ∼11−20 Å thick, of metal ion complexes of the grid type [Co4L4]8+·8PF6- and [Ag9L6]9+·9CF3SO3-, based on various ligands L, were prepared in-situ at the air-aqueous solution interface by the interaction of the free ligand molecules spread onto aqueous solutions containing Co2+ or Ag+ ions. The structure of the complex architectures composed of a 2 × 2 Co2+ grid coordinated to four ligand molecules and a 3 × 3 Ag+ grid coordinated to six ligand molecules as well as their molecular organization in thin films were characterized by grazing incidence synchrotron X-ray diffraction (GIXD) and specular X-ray reflectivity (XR) measurements performed at the air-aqueous solution interface and by UV, X-ray photoelectron spectroscopy (XPS), and scanning force microscopy (SFM) after film transfer onto various solid supports. The results open perspectives toward an implementation of the air−water interface for the self-assembly and subsequent deposition of organized arrays of complex inorganic architectures onto solid support.