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A series of arrays for light-driven charge separation is presented, in which perylene tetracarboxylic bisimide is the light-absorbing chromophore and electron acceptor, whereas isoxazolidines are colourless electron donors, the electron-releasing properties of which are increased with respect to the amino group by means of the alpha-effect. Charge separation (CS) in toluene over a distance ranging from approximately 10 to approximately 16 A, with efficiencies of approximately 95 to approximately 50 % and CS lifetimes from 300 ps to 15 ns, are demonstrated. In dichloromethane the charge recombination reaction is faster than charge separation, preventing accumulation of the CS state. The effects of solvent polarity and molecular structure are discussed in the frame of current theories.

Structure D 2000High-Pressure Syntheses and Characterization of the Transition Metal Borates β-MB 4 O 7 (M: Mn 2+ , Ni 2+ , Cu 2+ ). -The title compounds are synthesized from stoichiometric mixtures of B2O3 and MnO2, NiO, or CuO (7.5 GPa, 1000°C (Mn), 1150°C (Ni), 550°C (Cu)). The compounds crystallize isotypically to β-ZnB4O7 in the space group Cmcm with Z = 4 (single crystal XRD). The structures exclusively consist of BO4 tetrahedra, which form a network with channels of four-and six-membered rings. The transition metals are located within the six-ring channels. The compounds are further characterized by magnetic susceptibility measurements and UV/VIS spectroscopy. -(KNYRIM, J. S.; FRIEDRICHS, J.; NEUMAIR, S.; ROESSNER, F.; FLOREDO, Y.; JAKOB, S.; JOHRENDT, D.; GLAUM, R.; HUPPERTZ*, H.; Solid State Sci. 10 (2008) 2, 168-176; Fachbereich Chem. Biochem.,