A new class of pyrenyl solid-state emitters: 1-pyrenyl ynones. Synthesis via the Friedel–Crafts route, molecular and electronic structure and photophysical properties?

RSC Advances Pub Date: 2014-07-15 DOI: 10.1039/C4RA03961K

Abstract

Friedel–Crafts acylation of pyrene with alkynoic acids in the presence of trifluoroacetic anhydride and triflic acid constitutes a direct and efficient route to 1-pyrenyl ynones. These compounds in chloroform solution emit fluorescence at longer wavelengths, with higher quantum yields and longer lifetimes than a typical saturated acylpyrene derivative, 1-acetylpyrene. Moreover, in contrast to 1-acetylpyrene, they are moderate solid-state emitters. Comparative DFT studies revealed strong stabilization of the LUMOs of 1-pyrenyl ynones in comparison to the LUMO of 1-acetylpyrene. The single-crystal X-ray structure of 1-(pyren-1-yl)but-2-yn-1-one showed π-interactions of pyrenyl moieties in the crystal lattice. Investigations of the solid-state fluorescence of this compound revealed emission from long-lived excited states, including excimer species.

Graphical abstract: A new class of pyrenyl solid-state emitters: 1-pyrenyl ynones. Synthesis via the Friedel–Crafts route, molecular and electronic structure and photophysical properties
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