Six new donor‐bridge‐acceptor compounds have been synthesized which contain a long n‐tetradecyl chain attached to the donor or acceptor moiety, or to both of them. Systems 1, 2, and 3 are analogs of the fluorescent probe molecule Fluoroprobe (4). They contain a rigidly extended 4‐methylenepiperidine bridge and show relatively strong charge transfer fluorescence in solvents of low and medium polarity. Systems 1a, 2a, and 3a contain a semiflexible 4‐methylpiperidine bridge, obtained after hydrogenation of the exocyclic double bond of 1, 2 and 3, respectively. These systems undergo a conformational change following photoinduced charge separation (“harpooning”) in nonpolar solvents and probably also in solvents of medium polarity. Both the steady state fluorescence spectra and the fluorescence decay times of the extended charge transfer (ECT) species show that the photoinduced folding process is effectively slowed down by the introduction of the long alkyl tails. This is most pronounced for 1a which has an n‐tetradecyl group attached to both donor and acceptor. In solution a small difference in the rate of folding is observed between 2a and 3a, which have a single n‐tetradecyl chain attached to the acceptor only and to the donor only, respectively.

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Mikrometergroße Billardkugeln oder aber Stäbe können aus vesikelartigen Systemen gebildet werden, die sich um einen Polypropylenimin‐Dendrimerkern aufbauen. Das Design der Dendrimere erlaubt eine Feineinstellung der physikalischen Eigenschaften der Vesikel, sodass sie entweder wie Billardkugeln gegeneinander stoßen oder zu Stabstrukturen verschmelzen (siehe Bild).

The highly solvatochromic probe “Fluoroprobe”, which fluoresces in a wide range of the visible spectrum, was covalently attached to silica and alkylated silica particles to study solvent accessibility and surface micropolarity. A two step attachment method was used which was found to lead to a quite homogeneous distribution of the probes without extensive local clustering. On silica the probe experiences a local dielectric constant of ϵ = 6, while its solvent accessibility is ca. 30%. On alkylated silica this reduces to ϵ = 3.4 and ca. 23% respectively.

Mikrometergroße Billardkugeln oder aber Stäbe können aus vesikelartigen Systemen gebildet werden, die sich um einen Polypropylenimin‐Dendrimerkern aufbauen. Das Design der Dendrimere erlaubt eine Feineinstellung der physikalischen Eigenschaften der Vesikel, sodass sie entweder wie Billardkugeln gegeneinander stoßen oder zu Stabstrukturen verschmelzen (siehe Bild).