Controlled Assembly of Chiral One-Dimensional Helical Coordination Polymers for Circularly Polarized Luminescence and Polydimethylsiloxane-Assisted Signal Inversion and Amplification

Abstract

The controlled synthesis of circularly polarized luminescence (CPL) materials with high luminescent asymmetry factors (g_lum) and fluorescence quantum efficiency (Φ_PL) remain challenging. Herein, we present a straightforward and versatile approach, termed chiral capping strategy, to predictably construct chiral 1D helical coordination polymers (CPs) that exhibit strong CPL. The assembly of Zn(II), chiral auxiliary ligand [(1R,2R)-(+)/(1S,2S)-(−)-1,2-diphenylethylenediamine] (R/S-DPEDA), and fluorescent linkers 2-hydroxyterephthalic acid (HTA) or 2,6-dihydroxyterephthalic acid, affords two pairs of helical CPs, each demonstrating CPL activity with the highest g_lum and Φ_PL reaching up to 0.02 and 40%. The chiral chelate ligands not only orchestrate the self-assembly but also introduce and transfer chirality from the point-chirality of R/S-DPEDA to metal nodes and subsequently to the helical chains, which facilitate the effective integration of fluorescence and chirality, leading to a good CPL performance. By dispersing R/S-DPEDA-HTA into a polydimethylsiloxane matrix, transparent and flexible films with enhanced and inverted CPL are produced.