Multiphoton Absorption Iridium(III)-Organotin(IV) Dimetal Complex with AIE Behavior for Both Sensitive Detection of Tyrosine and Antibacterial Activity.

Multiphoton absorption chromophores have emerged as an attractive class of fluorescent agents for bioimaging in recent years. Here, we first report a cyclometalated Iridium(III)-organotin(IV) dimetal complex, which exhibits efficient multiphoton (from two- to three-photon) fluorescence. The three-photon absorption of IrSn1 is located in the NIR-II (second near-infrared window (900-1700 nm)) region. IrSn1 obtained aggregation-induced emission (AIE), emitting bright orange fluorescence (595 nm). IrSn1 can specifically target tyrosine, which shows an obvious multiphoton fluorescence enhancement under NIR-II region. Importantly, IrSn1 is alsoprovided a visible antibacterial activity toward Staphylococcus aureus in vitro and in vivo. Two-photon fluorescence bioimages and stimulated emission depletion (STED) microscopy indicated that IrSn1 could specifically recognize the nuclear thus leading DNA breaking in Staphylococcus aureus and cancer cells.