Chiroptical rhythmicity, part 1: Description of a novel phenomenon

A novel chiroptical phenomenon named "chiroptical rhythmicity" is described . Chiroptical rhythmicity consists of multiple reversible circular dichrois m Cotton effect sign inversions that follow a rhythmical pattern with respe ct to the continuous addition of a ligand (L-His) to the sample (a septi(p- phenylene)based receptor bound to phosphatidylcholine bilayers). Decrease a nd blue-shift of the L-1(a) absorption of the oligophenylene chromophore in dicated that partial "H" aggregation occurs during chiroptical rhythmicity. Based on stereochemical considerations for monomeric and tetrameric oligop henylenes, a hypothetical mechanism is discussed.