Photochemical ligand loss as a basis for imaging and microstructure formation in a thin polymeric film

Article abstract of DOI:10.1021/ja00182a007

Ligand loss photochemistry occurs in thin polymeric films of poly[Ru(bpy)₂(vpy)₂]²⁺ (bpy is 2,2′-bipyridine, vpy is 4-vinylpyridine), poly[Ru(Me₂bpy)₂(vpy)₂]²⁺ (Me₂bpy is 4,4′-dimethyl-2,2′-bipyridine), and poly[Ru(Me₄bpy)₂(vpy)₂]²⁺ (Me₄bpy is 4,4′,5,5′-tetramethyl-2,2′-bipyridine). These films were formed by reductive electropolymerization 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 in the exposed regions of the electrode by reductive electropolymerization. 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(vbpy)₃]²⁺ that remained.