Multi‐Directional Mechanofluorochromism of Acetyl Pyrenes and Pyrenyl Ynones. Issue 15 (29th June 2021)

• Record Type: Journal Article
• Authors: Hirai, Yuichi; Laize‐Générat, Lucie; Wrona‐Piotrowicz, Anna; Zakrzewski, Janusz; Makal, Anna; Brosseau, Arnaud; Michely, Laurent; Versace, Davy‐Louis; Allain, Clémence; Métivier, Rémi
• Is Part Of: Chemphyschem. Volume 22:Issue 15(2021)
• Page Start: 1638
• Page End: 1644
• Publication Date: 2021-06-29
• Subjects: fluorescence -- pyrene -- organic materials -- mechanofluorochromism -- solid state emission; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.202100294
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: A series of acetyl pyrenes and pyrenyl ynones with and without tert ‐butyl groups showed distinct mechanofluorochromism (MFC). Four pairs of polymorphic solids were found out of six compounds and interestingly, each of them showed hypsochromic, bathochromic or off‐to‐on MFC. The MFC properties were rationalized by categorizing the packing schemes into herringbone, sandwich, beta and gamma motifs depending on the relative contributions of C⋅⋅⋅C (or π‐π) against C⋅⋅⋅H contacts. The bulky tert ‐butyl and trimethylsilyl groups served not only to reduce the number of aggregation patterns but also to prohibit the complete back reactions in solid state. Our results suggest that the simple pyrene derivatives may be promising candidates for a novel group of mechanically‐sensitive materials. Abstract : Mechanically induced solid‐state fluorescence : Acetyl pyrenes and pyrenyl ynones with varied molecular arrangements show distinct emission property change upon mechanical stimuli, so‐called mechanofluorochromism. The direction of emission color change as well as the spontaneous solid‐state back reaction depend on the packing motifs and the steric hindrance of the side groups.