Tuning Solid‐State Emission Behavior of Janus‐Type Anthracenes by Addition of Shielding Bridges

Abstract

Traditional π‐face shielding is a useful technique to prepare emissive organic crystals. In this study, clip‐shaped ether bridges with silicon spacers were introduced into Janus‐type anthracenes with one shielded and one free π‐face to tune emission behavior systematically. Single‐crystal X‐ray structure analysis and emission spectra revealed that packing structures, emission color, and responsivity to stimuli depended on the size of the bridges. Anthracene molecules with short bridges resulted in clip‐anthracene and π‐π interactions between anthracene rings, leading to green emission in the solid state. In contrast, anthracenes with long bridges resulted in clip‐clip interactions without π‐π interactions, resulting in blue emission in the solid state. Hirshfeld surface analysis revealed that anthracenes with moderate bridges resulted in weak clip‐clip interactions in the crystal structure, which displayed mechanofluorochromism from blue to green emission.

Probing local structure of glass with orientation-dependent luminescence

“…Macrocycles were prepared by intermolecular annulation of 9,10-bis(triethoxysilyl)anthracene 27 and lithiated tethers, followed by reduction using LiAlH 4 (Fig. 1g and Fig.…”

“…Anthracene shows blue and green luminescence in the monomeric and dimeric states, respectively. 26,27 Moreover, the shift gradually increased from blue to green as the overlap between the anthracene rings increased. 28 The bathochromic shift should facilitate the detection of the intermolecular orientation during glass transition by energy transfer if the green fluorescence is related to the glassy state.…”