Steady-state fluorescence measurements and quantum-chemical DFT geometry optimizations are applied to extend the structure–property relationships between the free-base corrole macrocycle conformation and its basicity to the lowest excited S1 and T1 states. Direct basicity estimation in the lowest excited S1 state is demonstrated by means of fluorescence quantum yield measurements. The long wavelength T1 tautomer is found to retain its basicity in the S1 state, whereas the short wavelength T2 tautomer shows a noticeable decrease in basicity in the S1 state, which is related to the in-plane tilting of the pyrrole ring to be protonated. The conformational changes upon going from the ground to the lowest excited T1 state and the influence of the meso-aryl substitution pattern on the overall degree of distortions and tilting of the pyrrole ring to be protonated are also discussed from the point of view of macrocycle basicity.

中文翻译：

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激发态的科罗尔碱度：对结构-性质关系的见解

应用稳态荧光测量和量子化学 DFT 几何优化，将游离碱 corrole 大环构象与其碱度之间的结构-性质关系扩展到最低激发态 S1和T1状态。最低激发 S 中的直接碱度估计1状态通过荧光量子产率测量来证明。发现长波长 T1 互变异构体在 S1状态，而短波长 T2 互变异构体在 S 中的碱度显着降低1状态，这与要质子化的吡咯环的面内倾斜有关。从地面到最低激发 T 时的构象变化1状态和影响中观还从大环碱度的角度讨论了-芳基取代模式对要质子化的吡咯环的整体变形和倾斜程度的影响。