The TICT mechanism in 9,9'-biaryl compounds: Solvatochromism of 9,9'-bianthryl, N-(9-anthryl)carbazole, and N,N'-bicarbazyl

The UV-vis absorption and fluorescence spectra of 9,9'bianthryl (BA), N-(9-anthryl)carbazole (C9A), and N,N-bicarbazyl (BC) in 60 different solvents were precisely recorded. An analysis of the solvatochromic behavior of the three chromophores in terms of the polarity/polarizability of the solvents (SPP) revealed (a) that BC exhibits no TICT mechanism throughout the solvent polarity range studied and (b) that TICT emission prevails;in BA for solvents with SPP > 0.8 and in C9A for solvents with SPP > 0.6. One other interesting conclusion is that BA exhibits structured fluorescence at room temperature in three of the solvents studied. The presence of structure in the fluorescence of the three chromophores was studied also in DMSO solutions at 77 K.