Intramolecular Through-Space Interactions Induced Emission of Pillar[4]arene[1]dicyanobenzene

Abstract

Macrocycles modified with donor (D)–acceptor (A) motifs are generally believed as advanced organic fluorophores with exceptional photophysical properties. However, it is still necessary to develop intrinsic D–A-type macrocycles without complicated modifications due to their significant implications in fabricating high-performance emissive materials. Herein, we report on the photoluminescence properties of pillar[4]arene[1]dicyanobenzene (P5-2CN), a pillar[5]arene derivative containing one p-phenylene dicyano unit. The rigid pillar conformation and nonconjugated architecture endow P5-2CN with unanticipated intramolecular through-space charge transfer (TSCT) and aggregation-induced emission properties, by which the ratio of locally excited state emission and TSCT emission can be easily affected by their residing environment. Intriguingly, P5-2CN solid powder displays a profound vaporchromic behavior for common nitrile vapors with different hydrocarbon chain lengths. Experimental and theoretical analyses reveal that intramolecular through-space conjugation is critical for such unusual photoluminescence.