1,2‐Disubstituted 3,3,4,4,5,5‐Hexafluorocyclopentenes as Bent Light‐Emitting π‐Conjugated Luminophores

Abstract

Herein, a series of 1,2‐disubstituted 3,3,4,4,5,5‐hexafluorocyclopentene derivatives is synthesized from the commercially available octafluorocyclopentene via addition‐elimination reactions, and their photophysical properties are investigated in detail. 1,2‐Bis[2‐(4‐alkoxyaryl)ethyn‐1‐yl]‐3,3,4,4,5,5‐hexafluorocyclopentene exhibits UV‐absorption at 345 nm in CH2Cl2 and deep blue photoluminescence (PL). The PL properties of these derivatives, including color and maximum wavelength (λPL), are strongly affected by the electron‐density distribution induced by the electronic characteristics of the alkoxy‐substituents at the 4‐position of the benzene ring, with more electron‐donating substituents resulting in a larger shift of λPL to longer wavelengths. Note that the present light‐emitting π‐conjugated luminophores also exhibit relatively strong PL in the crystalline state, where λPL shifts can be introduced by modulation of the terminal alkoxy‐chain length, resulting in different PL colors from light‐blue to orange.