PHOTOINDUCED ELECTRON TRANSFER IN PORPHYRIN-QUINONE CYCLOPHANES .10. ZINC COMPLEXES OF PORPHYRIN-QUINONE CYCLOPHANES - SYNTHESES, STRUCTURES, AND ELECTRON-TRANSFER-RELATED-PROPERTIES

In order to increase the driving force for photoinduced electron-transfer reactions of porphyrin-quinone cyclophanes, the zinc complexes 3a-e and 4a-e were prepared from the corresponding cyclophanes of the 1 and 2 series. Electron-transfer-related properties like redox potentials and fluorescence spectra were determined for 3a-e and 4a-e. The Xray structure analysis of 4a indicates that for the very fast and solvent-independent electron transfer in these systems a specific mechanism involving an interaction of a quinone carbonyl group with the zinc might be considered as an alternative to through-space electron-transfer.