Synthesis and photophysical properties of doubly β-to-β bridged cyclic ZnII porphyrin arrays

Article abstract of DOI:10.1002/asia.201300035

A series of doubly β-to-β bridged cyclic Zn^II porphyrin arrays were prepared by a stepwise Suzuki-Miyaura coupling reaction of borylated Zn^II porphyrin with different bridge groups. The coupling of the building block of β,β′-diboryl Zn^II porphyrin with different bridges provided the doubly β-to-β carbazole-bridged Zn^II porphyrin array, the fluorene-bridged Zn^II porphyrin array, the fluorenone-bridged Zn^II porphyrin array, and the three-carbazole-bridged Zn^II porphyrin ring. The structural assignment of was confirmed by the X-ray diffraction analysis, which revealed a highly symmetrical and remarkably bent syn-form structure. The incorporation of bridge units with different electronic effects results in different photophysical properties of the cyclic Zn^II porphyrin arrays. Comprehensive photophysical studies demonstrate that the electron-withdrawing bridge fluorenone has the largest electronic interaction with the Zn ^II porphyrin unit among the series, thus resulting in the highest two-photon absorption cross-section values (σ⁽²⁾) of 6570±60 GM for. The present work provides a new strategy for developing porphyrin-based optical materials. Do you cross the bridge or do you fade away: Doubly β-to-β bridged cyclic Zn^II porphyrin arrays with carbazole, fluorene, and fluorenone as bridges were constructed. The incorporation of bridge units with different electronic effects results in different photophysical properties of the cyclic Zn^II porphyrin arrays.