Synthesis and photoinduced electron transfer characteristic of a bis (zinc porphyrin)-perylene bisimide array

In this article, a donor-acceptor array consisting of two zinc porphyrin (ZnPOR) units attached to the 1,7-positions of perylene-3,4:9,10-bis(dicarboximide) (PDI) was synthesized and characterized. This double-wing molecule exhibits very broad absorption in the region from 300 to 900 nm. Especially, its lower energy absorption feature presumably arises from donor-acceptor interactions. The fluorescence emission spectra confirmed that photoinduced electron transfer occurred from POR to perylene bisimide moiety in this triad. In contrast to previously studied systems incorporating POR and PDI groups, this array shows the evidence of a relatively strong ground-state electronic coupling between the donor and acceptor moieties. Additionally, highest occupied molecular orbital and lowest unoccupied molecular orbital values of the array were acquired by cyclic voltammetry (CV). The results showed that these energy values fulfill the energetic conditions required for the proposed electron transfer. More importantly, the photocurrent measurement showed that this molecule exhibits a high capacity to forma photoinduced charge-separated state and to produce steady and prompt cathodic photocurrent responses. These results confirmed the role of this new array toward harvesting light energy and generating photocurrent during the operation of a photoelectrochemical cell. Copyright (C) 2011 John Wiley & Sons, Ltd.