Here we report the design of a new coumarin-based photolabile protecting group with enhanced two-photon absorption. Two-photon excited fluorescence (TPEF), color-tuned ultrafast transient absorption spectroscopy and infrared (IR) measurements are employed to photochemically characterize the newly designed ATTO 390-DEACM-cargo triad. Increased two-photon cross-section values of the novel cage in comparison to the widely used protecting group DEACM ([7-(diethylamino)coumarin-4-yl]methyl) are extracted from TPEF experiments. Femtosecond pump–probe experiments reveal a fast intramolecular charge transfer, a finding that is confirmed by quantum chemical calculations. Uncaging of glutamate is monitored in IR measurements by photodecarboxylation of the carbamate linker between the photolabile protecting group and the glutamate, showing the full functionality of the novel two-photon activatable photocage.

中文翻译：

---

香豆素光笼的敏化双光子激活

在这里，我们报告了一种新的基于香豆素的光不稳定保护基的设计，该保护基具有增强的两光子吸收能力。两光子激发荧光（TPEF），颜色调谐的超快速瞬态吸收光谱和红外（IR）测量被用来对新设计的ATTO 390-DEACM货物三重态进行光化学表征。与广泛使用的保护基DEACM（[7-（二乙基氨基）香豆素-4-基]甲基）相比，新型笼的双光子横截面值增加了，是从TPEF实验中提取的。飞秒泵浦-探针实验揭示了分子内电荷的快速转移，这一发现已被量子化学计算所证实。在红外测量中，通过光不稳定的保护基团和谷氨酸之间的氨基甲酸酯连接基的光脱羧作用来监测谷氨酸的解笼。