Effect of Triarylamine Structure on the Photoinduced Electron Transfer to Boron Subphthalocyanine

Abstract

The photoinduced electron transfer (PET) reaction between a phenoxy-boronsubphthalocyanine derivative and a series of triarylamine electron donors was investigated. A series of triarylamines ranging in oxidation potentials and number of redox centers were prepared to study the effect of triarylamine structure on the photoinduced electron transfer (PET) reaction. In the case of multiple nitrogen centers, the triarylamines were dendritic in nature and were synthesized by a convergent strategy relying on successive C–N coupling and thermolytic deprotection steps. The efficiency of the PET reaction was found to be exponentially dependent on the oxidation potential of the triarylamine beyond a certain threshold. The free-energy change of the PET reaction was estimated using the Rehm–Weller equation, and this framework could be used to adequately explain the observed behavior of the system. We have concluded that the specific structure of the triarylamine is not important in the PET reaction and that efficiency...