Optical absorption and emission, electrochemical, and photochemical properties of peripherally functionalized with flexible and rigid π-extended substituents on A₂ and A₂B₂ type zinc porphyrins is investigated. The significance of rigid π-substituents over flexible ones in governing the spectral properties is unraveled. Flexible π-substituents on the porphyrin ring caused appreciable spectral broadening compared to porphyrin carrying rigid π-substituents. Further, supramolecular dyads are formed by coordinating phenyl imidazole functionalized fullerene, C60Im. The calculated binding constants for the 1:1 complexes is in the order of 2–7 × 10⁵ M−1 suggesting stable complex formation. Free-energy calculations performed according to the Rehm–Weller approach suggested possibility of excited state electron transfer in these dyads. Femtosecond transient absorption studies of the dyads performed in o-dichlorobenzene showed evidence of occurrence of electron transfer from the singlet-excited state that was in competition with the intersystem crossing process to populate the triplet-excited state of porphyrins.

中文翻译：

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A2 和 A2B2 功能化锌卟啉中的激发态电子转移携带刚性和柔性 β-吡咯 π-扩展取代基

具有柔性和刚性的外围功能化的光吸收和发射、电化学和光化学性质π_{研究了 A 2}和 A ₂ B ₂型锌卟啉上的延伸取代基。刚性的意义π- 取代基在控制光谱特性方面优于柔性取代基。灵活的π-与携带刚性的卟啉相比，卟啉环上的取代基引起明显的光谱展宽π-取代基。此外，超分子二元通过配位苯基咪唑官能化富勒烯，C60我是。1:1 复合物的计算结合常数约为 2–7 × 10 ⁵ M-1表明稳定的复合物形成。根据 Rehm-Weller 方法进行的自由能计算表明这些对子中存在激发态电子转移的可能性。飞秒瞬态吸收研究中进行的对子○-二氯苯显示出从单重激发态发生电子转移的证据，该电子转移与系统间交叉过程竞争以填充卟啉的三重激发态。