Two dendritic fullerene (DF) monoadducts, 2 and 3, which can carry up to 9 and 18 negative charges, respectively, were examined with respect to electrostatic complexation with Cytochrome c (Cytc). To facilitate comprehensive photophysical investigations, the zinc analogue of Cytc (ZnCytc) was prepared according to a novel, modified procedure. The association of ZnCytc and DF, and consequential photoinduced electron transfer within ZnCytc-DF from the photoexcited protein to the fullerene, was proven by fluorescence spectroscopy and transient absorption spectroscopy. These findings were also supported by circular dichroism as well as by extensive molecular dynamics (MD) simulations.

Redox gradients have been used to tailor the arrangement of photoactive ITO-electrodes at the molecular level.

Biomimetically synthesized silica and conductive activated carbon nanofibers (CNFs) are used in a synergistic manner for the development of a novel electrochemical biosensor system. Poly(L-lysine) templated silica grows and encapsulates the CNF-immobilized enzyme generating a highly stabilizing nanostructured environment for the underlying protein. Concurrently, CNFs provide both the required surface area for the high-capacity enzyme immobilization required in biosensors as well as direct electron transfer to the inner platinum transducer. As a result, this silica/nanofiber superstructure is an ideal architecture for the development of electrochemical biosensor systems that can withstand exposure to extreme operational conditions, such as high temperatures or the presence of proteases. Acetylcholine esterase is used as the model catalyst and with the aid of spectroscopic data it is shown that the observed high operational stability of the biosensor is due to the direct interaction of the protein with the silica backbone, as well as due to the nanostructured enzyme confinement.

The Coulomb complex formation of a dendritic fullerene oligocarboxylate (1 8 - ) and an octapyridinium zinc porphyrin salt (ZnP 8+ ) was investigated. A Job plot obtained by monitoring the Soret absorption of ZnP 8+ upon addition of 1 in a phosphate buffer (pH 7.2, ionic strength = 0.012) indicated the formation of a 1:1 complex, ZnP 8+ /1 8 - , for which an association constant of (3.5 ± 1.0) × 108 M-1 was determined. Parallel fluorescence titration experiments revealed that the ZnP 8+ emission is strongly quenched in the ZnP 8+ /1 8 - complex. In particular, the noted decrease of fluorescence intensity in ZnP 8+ with variation of 1 8 - and evidence for a new short-lived emissive component suggest a static quenching event inside a ZnP 8+ /1 8 - complex. From the fluorescence titration, a value of (1.1 ± 0.1) × 108 M-1 for the association constant of the ZnP 8+ /1 8 - complex at pH 7.2 was derived. The association constant decreased, however, when the ionic strength of the solution was raised. Electron-transfer quenching was confirmed by transient absorption spectroscopy, which showed the fingerprint absorptions of the ZnP 8+ radical cation and the 1 8 - radical anion and a lifetime of 1.1 μs for the charge-separated state. Molecular dynamic simulations offer insight into the supramolecular structure of the fullerene−porphyrin hybrid, ZnP 8+ /1 8 - .

The photocycloaddition of vinylcyclopropanes to C60 yields stereospecifically a five-membered [60]fullerene adduct. These results suggest a biradical intermediate of the [2 + 2] photocycloaddition between dienes or arylalkenes and C60. An electron transfer between the triplet excited state of C60 and the unsaturated substrates precedes the formation of the intermediate.