Taking Advantage of the Radical Character of Tris(2,4,6-trichlorophenyl)methyl To Synthesize New Paramagnetic Glassy Molecular Materials

This paper describes the synthesis of the novel bis[4-(N-carbazolyl)-2,6-dichlorophenyl](2,4,6-trichlorophenyl)methyl radical (2*) and tris[4-(N-carbazolyl)-2,6-dichlorophenyl]methyl radical (3*). A Friedel-Crafts reaction on [4-(N-carbazolyl)-2,6-dichlorophenyl)bis(2,4,6-trichlorophenyl]methyl radical (1*), 2*, and 3* leads to the introduction of acyl chains in the 3- and 6-positions of the carbazolyl moiety without impairment of the radical character of the molecule to give radicals 5*, 6*, and 7*. All of these novel radical adducts are thermally stable, 5* and 6* being amorphous solids by differential scanning calorimetry. Electron paramagnetic resonance spectra of them show a multiplet at low temperature due to the electron-coupling with six aromatic hydrogens. They show electrochemical amphotericity being reduced and oxidized to their corresponding stable anionic and cationic species, respectively. These radical adducts have luminescent properties covering the red spectral band of the emission with high intensities.