Synthesis, Structure, and Optoelectronic Properties of BN-Doped Tetraarylethylenes

A series of BN-doped tetraarylethylene (TAE) molecules (BTPE, E-DBDPE, Z-DBDPE, and TBPE) with highly twisted conformations were synthesized and characterized. X-ray crystallographic analysis confirms their propeller-like geometry, and no significant π-π stacking is observed. DFT and UV-vis results indicate that BN substitution affects molecular orbitals and photophysical properties in a manner dependent on the substitution number, orientation, and molecular backbone. While fluorescence is weak in THF, all compounds exhibit greatly enhanced and red-shifted emission in the solid state, with blue-shifts relative to carbon analogues. The AIE characteristics of these BN-doped TAEs were investigated in THF/water mixtures. The isoelectronic BN/CC strategy offers a simple and effective way to modify the properties of the TAE luminogens.