Efficient single benzene AIE system: Optical waveguide and invisible ink

The construction of novel aggregation-induced emission luminogens (AIEgens) is beneficial for the derivation of new organic materials and exploration of potential application of AIEgens. Herein, a symmetrical AIE single-benzene derivative MeDHQB which contains two aliphatic rings without typical aromatic rotors of propeller-like AIEgens was designed. Two crystal forms were discovered by controlling the crystallization conditions. It was found that the aliphatic rings weaken the structural rigidity and promote the molecular vibration, which drastically increase the nonradiative transition in solution and can be inhibited in the aggregate states. Meanwhile, the dissimilar polymorphic physicochemical properties of MeDHQB-I and MeDHQB-II were investigated by experimental and theoretical methods. Additionally, the thermal transformation from MeDHQB-I to MeDHQB-II and the potential applications of optical waveguide and invisible ink were carefully discussed. Results presented in this work provide an efficient strategy for the construction of multifunctional AIE fluorophore based on compact single-benzene system.