Solid-State Emissive Pillar[6]arene Derivatives Having Alternate Methylene and Nitrogen Bridges

Chem Asian J. 2024 Feb 21:e202400106. doi: 10.1002/asia.202400106. Online ahead of print.ABSTRACTMacrocyclic arenes show conformational adaptability, which allows host-guest complexations with the size-matched guest molecules. However, their emission properties are often poor in the solid states due to the self-absorption. Herein, we newly synthesized pillar[6]arene derivatives having alternate methylene and nitrogen bridging structures. Solvatochromic study reveals that the nitrogen-embedding into the cyclic structures can strengthen the intramolecular charge transfer (CT) nature compared to that of the linear nitrogen-bridged precursor. Owing to the large Stokes shift in the solid state, one of the nitrogen-embedded pillar[6]arenes shows high absolute photoluminescence quantum yield (ΦPL = 0.36). Furthermore, it displays a turn-off sensing ability toward nitrobenzene (NB) vapor; a fluorescence quenching is observed when exposed to the NB vapor. From the structural analysis before and after the exposure of NB vapor, the amorphous nitrogen-embedded pillar[6]arene efficiently co-crystallize with NB and formed non-emissive intermolecular CT complexes with NB.PMID:38380963 | DOI:10.1002/asia.202400106

Source: Chemistry, an Asian Journal - February 21, 2024 Category: Chemistry Authors: Shunsuke Ohtani Kazeto Nakaguchi Kenichi Kato Tomoki Ogoshi Source Type: research