文摘
Diketopyrrolopyrrole (DPP) derivatives are very promising nonlinear optical dyes with excellent thermal resistance and light stability. However, to the best of our knowledge, the fabrication of their organic micro- and/or nanostructures through covalent and/or noncovalent interactions to further adjust their corresponding two-photon absorption (TPA) is rarely reported. In this work, based on previous synthesis method of pyridine-containing ketopyrrolopyrroles, three dipyridyldiketopyrrolopyrroles (dipyridylDPPs) 1, 2, and 3 containing 2-, 3-, and 4-pyridyl substituents, respectively, have been prepared, which exhibit strong orange fluorescence and large TPA action cross-sections in both organic (tetrahydrofuran) and aqueous media. Importantly, fluorescent organic nanoparticles (FONs) of the di(2-pyridyl)DPP 1 prepared by the reprecipitation method displays strong two-photon emission. Meanwhile, the FONs of 1 not only exhibit Ag+ ions mediated self-assembly modulation, but also display low cytotoxicity and allow two-photon bioimaging in HeLa cells.