Spirolactam rhodamines are fluorescent photoswitches that are useful for single molecule localization microscopy, volumetric 3D digital light photoactivatable dye displays, and other applications. Measurement of the photophysical properties, particularly photoswitching kinetics and quantum yields, is challenging and a comprehensive understanding of how molecular structure affects these parameters remains incomplete. In this study, we have synthesized a series of N‐aryl spirolactam rhodamine photoswitches with fluorescent emissions at 585 nm and 518 nm. Extinction coefficients and fluorescence quantum yields of the fluorescent form of the photoswitch have been measured using excess trifluoroacetic acid to drive the equilibrium to the open form. A method to determine photoswitching kinetics and quantum yields was developed by monitoring the kinetics to reach equilibrium between the on‐state and off‐state and fitting this data to a rate equation for a reaction in equilibrium. Trends based on the electronic and steric properties of the aryl substituents were evaluated. Using this information, a proof‐of‐principle demonstration of 3D voxel formation was accomplished using a green (518 nm) emitting photoswitch, setting the foundation for a multi‐colour volumetric 3D display.

中文翻译：

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调节螺内酰胺罗丹明光电开关的光物理性质

螺内酰胺若丹明是荧光光电开关，可用于单分子定位显微镜，体积3D数字光可光活化染料显示器和其他应用。光物理性质，特别是光开关动力学和量子产率的测量是具有挑战性的，并且对分子结构如何影响这些参数的全面理解仍然不完整。在这项研究中，我们合成了一系列N‐芳基螺内酰胺若丹明光敏开关，在585 nm和518 nm处发出荧光。光开关的荧光形式的消光系数和荧光量子产率已使用过量的三氟乙酸驱动平衡达到开放形式进行了测量。通过监测动力学以达到开态和关态之间的平衡并将此数据拟合到平衡中的反应速率方程，从而开发了一种确定光开关动力学和量子产率的方法。评价了基于芳基取代基的电子和空间特性的趋势。利用此信息，使用绿色（518 nm）发射的光电开关完成了3D体素形成的原理证明，从而为多色体积3D显示器奠定了基础。