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(center dot)) and tris[4-(N-carbazolyl)-2,6-dichlorophenyl]methyl radical (3(center dot)). A Friedel-Crafts reaction on [4-(N-carbazolyl)-2,6-dichlorophenyl)bis(2,4,6-trichlorophenyl]methyl radical (1(center dot)), 2(center dot), and 3(center dot) 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(center dot), 6(center dot), and 7(center dot). All of these novel radical adducts are thermally stable, 5(center dot) and 6(center dot) 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.