Tris(2,2'-bipyridine)ruthenium(II) complexes, Ru(bpy)32+, were covalently linked to viologen units to afford a model of man-made photoreaction centers. The emission from the ruthenium complex in the photoreaction centers was almost completely quenched by the linked viologen units. The relative quantum yields ( " ) of the photoinduced reduction of viologen units in the presence of the electron donor EDTA were 1-2% of those for the free Ru(bpy)32+-methyl viologen system in aqueous solutions. The ß values, however, remarkably increased in the combined system which consisted of the photoreaction center and the electron relay systems of aligned viologen units (micelle, polymer, and polysoap). The effect was attributed to the enhancement of charge separation of the photoproduced primary ion pair due to electron injection from the photoreaction centers into the electron relay system and the succeeding electron migration.

Polypyridineruthenium(II) complex with linked viologen units was synthesized as the model of man-made photoreaction center. Luminescence quenching of the ruthenium complex by a surfactant-type viologen in micellar or bilayer membrane systems was resolved into inter- and intramolecular processes and it became apparent that the photoinduced charge separation in intramolecular process was more efficient than that in intermolecular process.

Formation of organogels from europium(III) complexes consisting of ligands having an amide or a urea unit has been achieved; the organogels are characterized by strong red-emissions.

Dithia[3.3]metacyclophanes with a urea unit having long alkyl chains have been prepared. It has been found out that some of them give stable organogels in some solvents, and their gelating ability depends on structural properties of both aromatic components in the dithia[3.3]metacyclophane.

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