Photoinduced Electron Transfer within Porphyrin-Anthra-quinone Dyads Connected by Hamilton Hydrogen Bonding†

摘要

AbstractPorphyrin- or zinc-porphyrin-cyanuric acid conjugants (TPP-CA or ZnTPP-CA) and anthraquinone connected with the known "Hamilton receptor" (AQ-H) were synthesized. The supramolecular dyads constructed via the AQ-H and TPP-CA/ZnTPP-CA exhibit six hydrogen bonds, which provide the association constant K_APP approximately (2.8±0.3)×103 mol−1·L in toluene. Selective excitation of the porphyrin/zinc porphyrin chromophores results in an electron transfer between TPP-CA/ZnTPP-CA and AQ-H within the supramolecular assemblies, leading to an efficient quenching of the TPP-CA/ZnTPP-CA fluorescence. The singlet electron transfer from porphyrin/ zinc-porphyrin to anthraquinone proceeds mainly via a 'through space' mechanism with efficiencies of 43%, 58%, and rate constants of 7.6×107, 7.0×108 s−1, respectively.