Abstract
Fluorescent double-helical monometallofoldamers [Ag-(1)(2)]-[PF(6)] were constructed by the mononuclear complexation of two bipyridine strands 1 featuring two L-shaped dibenzopyrrolo-[1,2-a]-[1,8]-naphthyridine units at both ends with a Ag-(I) cation. These monometallofoldamers exhibited double-helical/open conformational switching. [(R)-Ag-(1c)(2)]-[PF(6)] with chiral side chains induced a single-handed helix sense and enabled precise control of M/P helicity switching in response to a solvent. This complex also exhibited strong fluorescence and circularly polarized luminescence (CPL) inversion switching upon M/P helicity inversion. For instance, [(R)-Ag-(1c)(2)]-[PF(6)] exhibited positive CPL in CH(2)Cl(2) (φ(F) = 0.69, g (lum) = 1.9 × 10(-3)) and negative CPL in toluene (φ(F) = 0.79, g (lum) = -2.0 × 10(-3)). This double helix also aggregated in polar solvents, which led to CPL inversion switching induced by temperature- and concentration-dependent aggregation.