Enhanced three-photon activity trigged by AIE behavior of a novel terpyridine-based Zn(II) complex bearing thiophene bridge
Multiphoton bioimaging benefits from greater tissue penetration, low phototoxicity and high resolution. As a result, the development of efficient multiphoton imaging agents is highly desirable and remains challenging. Herein, a novel terpyridine-based Zn(II) complex bearing thiophene bridge has been rational designed and fabricated. Thanks to its aggregation induced emission (AIE) characteristic, DZ1 emits bright yellow-green fluorescence (λem = 575 nm) in physiological conditions. The three-photon spectral changes of DZ1 when binding with RNA unambiguously reflect its RNA-specific targeting behavior, resulting in 2.0 times enhancement in three-photon action cross-sections located at the second near-infrared window (NIR-II, 1700 nm).