Deep blue fluorescent 2,5-bis(phenylsilyl)-substituted 3,4-diphenylsiloles: Synthesis, structure and aggregation-induced emission

A series of 2,5-bis(phenylsilyl)-substituted 3,4-diphenylsiloles were synthesized by one pot reaction in moderate yields (47-66%) and characterized by NMR, Mass and elemental analysis. Their crystals were grown from THF/methanol mixtures and analyzed by single-crystal X-ray diffraction. The electronic structures and energy levels were calculated by B3LYP/6-31G(d) basis set. The results show that these new siloles possess a flexible conformation with novel sigma-pi* conjugation. The absorption and fluorescence spectra were measured in the solution and aggregate states. Whereas they are weakly fluorescent in solutions, they are induced to emit strong deep blue light in solid films and crystals, demonstrating an aggregation-induced emission (AIE) characteristic. (C) 2013 Elsevier Ltd. All rights reserved.