PHOTOCHEMICAL LIGAND LOSS AS A BASIS FOR IMAGING AND MICROSTRUCTURE FORMATION IN A THIN POLYMERIC FILM

Ligand loss photochemistry occurs in thin polymeric films of poly[Ru(bby)2(vpy)2]2+ (bpy is 2,2'-bipyridine, vpy is 4-vinylpyridine), poly[Ru(Me2bpy)2(vpy)2]2+ (Me2pby is 4,4'-dimethyl-2,2'-bipyridine), and poly[Ru(Me4bpy)2(vpy)2]2+ (Me2bpy is 4,4',5,5'-tetramethyl-2,2'-bipyridine). These films were formed by reductive eletropolymerization of the corresponding 4-vinylpyridine complexes on Pt disk electrodes. Upon photolysis, the ruthenium-pyridyl bonds were cleaved and the polymer was lost, exposing the underlying substrate. The photochemical reaction was used to transfer an image to the films by using masking techniques. In a subsequent step, poly]Os(vbpy)3[2+ (vbpy is 4-methyl-4'-vinyl-2,2'-bipyridine), which is photochemically stable, was formed selectively n the exposed regions of the electrode by reductive eletropolymerization. This procedure gave a laterally resolved, two-component, film-based structure in which there were discrete, spatially segregated regions of Ru(II)and Os(II). In a final step, the remaining film containing Ru(II) was removed by photolysis. This procedure left an image of the original mask in the poly[Os(vbyp)3]2+ that remained.