AIE‐Active Chiral [3]Rotaxanes with Switchable Circularly Polarized Luminescence

Abstract

The construction of circularly polarized luminescence (CPL) switches with multiple switchable emission states and high dissymmetry factors (glum) has attracted increasing attention due to their broad applications in diverse fields such as the development of smart devices and sensors. Herein, a new family of AIE‐active chiral [3]rotaxanes were designed and synthesized, from which a novel CPL switching system was successfully constructed. The switching process was realized through the controlled motions of the chiral pillar[5]arene macrocycles along the axle through the addition or removal of the acetate anions, which not only modulated the chirality information transfer but also tuned the aggregations of the integrated [3]rotaxanes, thus resulting in reversible transformations between two emission states with both high photoluminescence quantum yields (PLQYs) and high dissymmetry factors (glum) values.

Chiral assembly of organic luminogens with aggregation-induced emission

“…A switchable CPL system based on chiral [3]rotaxanes 26 was developed by Yang. 75 The addition or removal of acetate anions can control the movement of the chiral pillar [5]arene macrocycles along the axle to result in switching between two emissions with high photoluminescence quantum yields (PLQYs) and g em values. Jiang realized multicolor tunable CPL in a single AIE molecule by attaching pyridine-modied cyanostilbene to a chiral unit 27.…”

“…Recently, a novel CPL switching system based on AIE-active chiral [3]rotaxanes 26 was reported by Yang. 75 As shown in Fig. 14, a typical AIEgen 9,10-distyrylanthracene (DSA) was utilized as a core, thiourea moieties were selected as the binding sites and pillar [5]arene macrocycles (DEP[5]A) were chosen as the stereogenic units and wheel components.…”

Chiroptical Properties of Mechanically Interlocked Molecules

“…It is important to emphasize that the quantum yield as well as absorption and emission profiles of the rotaxane were substantially unaffected by this process and that three complete on/off cycles could be performed. On the other hand, He and Wang [104] prepared an anion switch based on a [3]rotaxane containing two planar chiral pillar [5]arenes and an emissive 9,10-distyrylanthracene moiety. In its aggregate state, the j g lum j value increased from 0.21 × 10 À 2 to 1.36 × 10 À 2 in the presence of acetate anions as a result of an enhancement of chirality transfer, since the chiral macrocycles move closer to the emissive group of the rotaxane.…”

AIE‐Active Chiral [3]Rotaxanes with Switchable Circularly Polarized Luminescence

“…Single crystals suitable for crystallographic analysis were obtained by slow diffusion of acetone into the dichloromethane solution of 1. [15] To our surprise,a sr evealed by the resultant single crystal structure,t wo pillar [5]arene wheels,o ne with (pS, pS, pS, pS, pS)conformation and the other with (pR, pR, pR, pR, pR)c onformation, individually encircled the axle, affording [3]rotaxane 1 in the meso form (Detailed discussion of the absolute configurations of 1 will be given below). As expected, attributed to the hydrogen-bonding interactions between the thiourea moiety as well as the trifluoromethyl moiety and the ethoxy group of DEP [5]A, respectively,t he DEP [5]A wheels were located at the thiourea and adjacent methylene moieties,w hich laid the foundation for the investigations of its stimuli-responsive feature discussed in the next section (Figure 2b).…”