Synthesis, structural and spectral properties of diarylamino-functionalized pyrene derivatives via Buchwald–Hartwig amination reaction

A new series of diarylamino-functionalized pyrene derivatives, namely, 1-(N,N-diarylamino)-substituted pyrenes (7), isomer of 1,6-bis- and 1,8-bis(N,N-diarylamino)-substituted pyrenes (8/9) and 1,3,6,8-tetrakis(N,N-diarylamino)-substituted pyrenes (10) have been synthesized. The structures of these synthesized compounds were determined on the basis of spectral data and elemental analysis. All compounds 7–10 have bright fluorescent emissions from sky-blue to green in solution condition (λmax = 464–500 nm in CH2Cl2) and high emission efficiency (Φf = 0.84–0.96 in dichloromethane). All compounds have high thermal stability and good solubility in common organic solvents. The electronic properties of these compounds were determined by spectroscopic methods such as UV–vis absorption spectroscopy and fluorescence emission spectroscopy. Clear evidences were obtained that the longest wavelength bands of these compounds are bathochromically red-shifted as the number of the diarylamino-substituent increased.

► Diarylamino-pyrenes were synthesized by a modified Buchwald–Hartwig amination reaction.
► All compounds emit very bright fluorescent emissions in solution (Φf = 0.84–0.96 in dichloromethane).
► Diarylamino groups suppress π-stacking in the solid state.