Reversible Chiral Memory in Ruthenium Tris(phenanthroline)-Anionic Porphyrin Complexes .

J aggregates of the tetraanionic meso-tetrakis(4-sulfonatophenyl)porphine (H2TPPS4) gain chirality by interaction with ?- or ?-[Ru] ([Ru]=[Ru(1,10-phenanthroline)3]2+). After destroying and reforming the aggregates by changing the pH of the solution, the final species "remember" the initially imprinted chirality, even in the presence of an excess of the ruthenium complex with the opposite chirality to that memorized.