Amplified circularly polarized luminescence in assembly of terpyridine-ZnII and GTP induced by silver(I) ion

Abstract

The G-quartet, a hydrogen-bonded macrocycle formed by cation-templated assembly of guanosine derivative, plays a vital role in areas ranging from structural biology to supramolecular chemistry and nanotechnology. Herein, we show a zinc-terpyridine derivative (Ftpy) that could form complex with various guanosine phosphates, exhibiting relatively weak circularly polarized luminescence CPL (dissymmetry factor, g_lum ≈ 1 × 10⁻³). Interestingly, when Ag⁺ ions are involved, significantly boosted circularly polarized luminescence (CPL) is obtained in the assemblies of Ftpy with GTP, which the g_lum can reach to 0.15. In contrast, no significant difference is observed in the presence of other cations (Na⁺, K⁺, Rb⁺, NH₄⁺, Cu²⁺, and Sr²⁺). It reveals that CPL signal is amplified due to the formation of G-quartet in the presence of Ag⁺ ions, which further hierarchically self-associate into helically stacked supramolecular aggregates with the cooperation and π-π of Ftpy, contributing to the expression of chirality information. Furthermore, the co-assemblies of Ftpy/GTP/Ag⁺ exhibit an enantioselective recognition of enantiomeric penicillamine by CPL spectra. This work provides a straightforward avenue to fabricate supramolecular assemblies with strong CPL based on G-quartet formation.