ENHANCEMENT OF INTRAMOLECULAR EXCIMER FORMATION OF 1,3-BICHROMOPHORIC PROPANES VIA APPLICATION OF HIGH PRESSURE and VIA COMPLEXATION WITH CYCLODEXTRINS. PROTECTION FROM OXYGEN QUENCHING

Abstract— The emission of several 1,3-bichromophoric(BC) systems has been investigated in aqueous solutions containing various cyclodextrins (CD's). In all cases where molecular models reveal that the correspondence of the size and shape of the eclipsed conformation of the BC system and the cavity CD is high, a stable CD (host)-BC (guest) complex is formed and in these cases, the ratio of excimer to monomer emission intensity UE/IM) is much larger than that found in homogeneous solution. The effect of application of high pressure on the I_E/I_M ratio was investigated, as was the influence of 0₂ quenching of excimer and monomer in homogeneous solutions, in aqueous micellar solutions, and in aqueous solutions of CD complexes. A strong protection from 0₂ quenching is observed in the latter case.