A donor-acceptor dyad with a highly Lewis acidic boryl group

A donor - pi - acceptor dyad with a highly electron-deficient B(C6F5)(2) group as the acceptor has been prepared. 5-Diphenylamino-5'-bis(pentafluorophenyl)boryl-2,2'-bithiophene (3) was fully characterized by multinuclear NMR spectroscopy, mass spectrometry, and X-ray crystallography. The solid-state structure of 3 shows the presence of multiple pi-stacking interactions rather than Lewis acid - base bonding between boron and nitrogen. Cocrystallized benzene molecules are incorporated into a channel-like framework of 3. The electronic structure and photophysical properties were investigated by UV - visible absorption and emission spectroscopy and DFT calculations. The absorption and emission maxima experience a strong bathochromic shift relative to the non-fluorinated analogues, the origin of which has been further examined by DFT calculations.