Six porphycenes have been synthesized, bearing one, two, or three fluorine atoms attached directly to the 18‐π‐electron system at the meso positions. These novel compounds have been characterized by structural, electrochemical, and spectral techniques, combined with quantum chemical calculations. In three fluoroporphycenes, the unsymmetric substitution pattern leads to the presence of two nonequivalent trans tautomeric forms. They have been identified using electronic absorption, emission, and magnetic circular dichroism spectroscopies. Their relative energies have been estimated for the ground and lowest excited electronic states. Tautomerization potential is quasi‐symmetric in S₀, but becomes strongly nonsymmetric in S₁. Femtosecond transient absorption studies allowed determination of tautomerization rates, larger and similar for both directions of the double hydrogen transfer in S₀, lower and disparate in S₁. Fluoroporphycenes emerge as good candidates for detailed studies of mechanisms of double hydrogen transfer, as well as processes responsible for rapid radiationless excited state depopulation.

中文翻译：

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氟化卟啉：合成，光谱学，光物理和互变异构

已经合成了六个卟啉，带有一个，两个或三个氟原子，这些氟原子直接连接到内消旋位置的18-π-电子系统上。这些新型化合物已通过结构，电化学和光谱技术与量子化学计算相结合进行了表征。在三个氟卟啉中，不对称取代模式导致存在两种不等价的反式互变异构形式。使用电子吸收，发射和磁性圆二色性光谱法已鉴定出它们。对于基态和最低激发电子态，已估计出它们的相对能量。互变异构电势在S _0中是准对称的，但在S _1中变得很不对称。飞秒瞬态吸收研究允许确定互变异构率，互变速率大且相似，S _0中双氢转移的两个方向，S _1中较低且完全不同。氟卟啉类化合物是详细研究双氢转移机理以及引起快速无辐射激发态人口减少的过程的良好候选者。