Planar and Bent BN-Embedded p‑Quinodimethanes Synthesized by Transmetalation of Bis(trimethylsilyl)-1,4-dihydropyrazines with Chloroborane

Two BN-embedded p-quinodimethane derivatives were synthesized by a reaction of bis­(trimethylsilyl)-1,4-dihydropyrazines, which are known as inorganic-salt-free reductants, with 9-chloro-9-borafluorene. The planar or bent structures of the resulting π-conjugated compounds were revealed by X-ray diffraction analysis. Their photophysical properties relate to their planar or bent structures due to the difference in the distribution of the HOMO.