| Popis: |
The ability of scientists to convert light into stored chemical potential energy has increased over the past ten years.1 A critical component of this development has been the sophistication of the synthesis of multi metal systems.1~2 Conceptually, the design of individual, but coupled, components in supramolecular systems with specific properties such as light absorption, light emission, chemical reaction, charge storage and conductivity are now possible through elaborate synthetic schemes.2 However, little is known about the coupling of these components. Extensive electronic coupling may perturb the desired characteristics of the mononuclear fragments. On the other hand, minimal coupling may preclude energyor electron-transfer processes within the lifetime of the excited state of the molecular ensemble. Our goal in this paper is to outline some of the design constraints present in supramolecular systems in terms of the coupling of metal centers in excited-state, energyand electrontransfer processes. Metal azine systems have been used extensively in the design of multimetal complexes. 13 One reason for this extensive use in the longlived excited state of complexes such as Ru(bpy)$+, where bpy = 2,2’bipyridine. Another reason is that polyazaaromatic ligands form stable, chelating, bridging ligands. The azines used as bridging and terminal ligands in this work are pictured in Figure 1. |
