Metallosupramolecular coordination polyelectrolytes: potential building blocks for molecular-based devices.

Metal-ion-induced self-assembly of ditopic ligands, based on bisterpyridines, and transition metal ions result in formation of metallosupramolecular coordination polyelectrolytes (MEPE). The positive charge of MEPE can be utilized in several ways to process highly ordered architectures. Alternating adsorption of MEPE and oppositely charged polyelectrolytes on solid substrates results in multilayers. The sequential nature of this process allows combining MEPEs with other functional components. This process permits nanometer thickness control, is readily adapted for automated processing, and is applicable to two-dimensional substrates as well as to colloidal templates. The surface chemical properties of MEPE are readily controlled by complexing MEPE with negatively charged amphiphiles. The resulting polyelectrolyte-amphiphile complexes (PAC) are soluble in organic solvents and form liquid crystalline phases. The PAC also spreads at the air-water interface as Langmuir monolayer, which can be transferred onto solid substrates. The resulting Langmuir-Blodgett multilayers are highly ordered and anisotropic. Materials with transition metal ions possess many interesting properties, including spin transitions, magnetism, as well as photochemical assets that are relevant for the construction of functional devices and materials. The presented approach combines principles of supramolecular and colloidal chemistry as well as surface science, is highly modular in nature, and provides extensive control of structure and function from molecular to macroscopic levels.