Informative secondary chiroptics in binary molecular organogel systems for donor–acceptor energy transfer

Pyrene-doped l-glutamide-based lipidic derivatives with different alkyl lengths (Cn-g-Pyr; n = 4, 8 and 12) were newly synthesized. All of the Cn-g-Pyr dissolved and showed thermotopically and lyotropically-induced excimer formations accompanied by induction of the positive Cotton effect in their CD spectra, indicating chirally ordered stacking. However, when C4-g-Pyr and C12-g-Pyr were mixed in a certain molar ratio, an unusual CD pattern from positive to negative ones was observed. In this study, energy transfer efficiency was investigated in a binary system of Cn-g-Pyr with C12-g-TPP. The results revealed that simple modification of the alkyl length of Cn-g-Pyr enables enhancement of the energy transfer efficiency with C12-g-TPP.