A Series of Imidazole Derivatives: Synthesis, Two-Photon Absorption, and Application for Bioimaging

Abstract

A new series of D-π-A type imidazole derivatives have been synthesized and characterized. Two corresponding imidazolium salts (iodine and hexafluorophosphate) were prepared from the imidazole compound. Their electron-withdrawing ability can be largely tunable by salt formation reaction or ion exchange. UV-vis absorption and single-photon fluorescence spectra have been systematically investigated in different solvents. The two-photon cross sectionsδ2PAof the imidazole derivatives are measured by two-photon excited fluorescence (2PEF) method. Compared with those ofT-1(107 GM) andT-3(96 GM),T-2(imidazolium iodine salt) has a large two-photon absorption (2PA) cross section value of 276 GM. Furthermore, the cytotoxicity and applications in bioimaging for the imidazole derivatives were carried out. The results showed thatT-1can be used as a lysosomal tracker with high stability and water solubility within pHs of 4–6, whileT-2andT-3can be used as probes for cell cytoplasm.