| Popis: |
Upon photoexcitation of fixed-distance triads cosisting of zinc-porphyrin (ZnP) or magnesium-porphyrin (MgP), a doubly strapped metal-free porphyrin (SH 2 P), and pyromellitimide (PIm), (ZnP) + SH 2 P(PIm) − and (MgP) + SH 2 P(PIm) − ion pair states are produced in high yields by two-step electron-transfer reactions: (1) charge separation between 1 (SH 2 P)* and PIm and (2) hole transfer from (SH 2 P) + to the metalloporphyrin. A (MgP) + SH 2 P(PIm) − ion pair state is fairly long-lived, while a (ZnP) + SH 2 P(PIm) − state is only short-lived due to a decay pathway to the ground state through a reverse hole transfer to give ZnP(SH 2 P) + (PIm) − followed by charge recombination. |
