Chiral sign selection on the J‐aggregates of diprotonated tetrakis‐(4‐sulfonatophenyl)porphyrin by traces of unidentified chiral contaminants present in the ultra‐pure water used as solvent

Traces of biological contaminants that cannot be detected, but are expected to be present, in ultra-pure water suffice to select the emerging chiral sign in the spontaneous mirror symmetry breaking that takes place during the formation of the J-aggregates of the amphiphilic diprotonated tetrakis-(4-sulfonatophenyl)porphyrin (H(4)TPPS(4)(2-)). This is demonstrated by competition experiments with a chiral cationic surfactant. The sensitivity of the detection depends on the hierarchical control of the H(4)TPPS(4)(2-) self-aggregation.