Syntheses, spectral properties of novel carbazole derivatives and evaluations of its Ct-DNA interaction

A series of carbazole derivatives were synthesized via reactions of C-N bond formation catalyzed by CuBr·SMe₂, nitration, reduction as well as Pd-catalyzed C-N crossing coupling, respectively. Their UV-Vis and fluorescence spectra in different solvents were investigated, as well as the evaluation of the interaction between compound 2 hydrochloride and Ct-DNA. The results showed that all compounds exhibited distinct solvatochromism effects and among them, compound 4 was the most obvious one. Upon binding with DNA, the fluorescence of compound 2 hydrochloride turned on, instead of quenching, and the minor groove of DNA is the most possible position for the molecule to bind with. The calculated binding constant is around 10⁴L·mol^-1, showing a moderate binding affinity.