Water-soluble two-photon absorption benzoxazole-based pyridinium salts with the planar cationic parts: crystal structures and bio-imaging

摘要

Six new benzoxazole-based compounds 1-6 of the donor-bridge-accepter (D-pi-A) type with different anions were obtained by methylation and anion exchange reaction. The single crystals of 1, 3 and 6 were obtained by slow evaporation of acetonitrile and determined by X-ray crystallography. Ellipsoidal structures of the three compounds showed that the cationic parts all maintained good planarity, which was beneficial for two-photon absorption (2PA) properties and accorded with the results of two-photon excited fluorescence tests. Biological imaging experiments showed water-soluble six compounds had excellent penetrability in living cells and could located in cytoplasm in one- and two-photon cell imaging. Biological imaging result of compound 6 was more excellent than other compounds, which indicated synergy of anions and cations played a very important role in cell imaging. (C) 2017 Elsevier Ltd. All rights reserved.