Hydrogen bonding-mediated foldamer-bridged zinc porphyrin-C60 dyads: ideal face-to-face orientation and tunable donor–acceptor interacion

Four porphyrin-bridge-C60 dyads have been synthesized by covalently linking the chromophores at the opposite ends of a hydrogen bonded arylamide-derived foldamer bridge. For comparison, four C60-free porphyrin derivatives of the same frameworks have also been prepared. The fully hydrogen bonded bridges enable the appended porphyrin and C60 moieties to contact in a face-to-face manner. 1H NMR, UV–vis and fluorescent investigations in chloroform indicate that such a structural matching remarkably facilitates the intramolecular energy and electron transfer and charge separation between the two chromophores and also retards the recombination of the charge-separated state. Removing one hydrogen bond considerably reduces the energy and electron transfer. Further removing another one leads to no important interaction between the chromophores to occur.