New fluorescent aryl- or ethynylaryl-boron-substituted indacenes as promising dyes

A generic design principle based on the use of organometallic (Li or Mg) reagents for the substitution of the fluoro ligands in difluoroboradiazaindacene is described. A library of compounds bearing various substituents (butyl, phenyl, naphthyl, pyrenyl, ethynylnaphthyl, ethynylfluorenyl, ethynylcarbazoyl, ethynylperylenyl, ethynylthiophenyl and ethynylterpyridinyl) has been prepared and characterized. Electrochemical and photochemical measurements show that these novel dyes remain redox-active and strongly luminescent. They offer an interesting perspective for applications in labelling and electroluminescence.