Synthesis and photophysical properties of a [60]fullerene compound with dimethylaniline and ferrocene connected through a pyrazolino group: a study by laser flash photolysis

Pyrazolino[60]fullerene covalently-linked to ferrocene and N,N-dimethylaniline groups has been prepared and studied using time-resolved spectroscopic methods. The fluorescence quenching of the C(60) moiety indicates that charge-separation takes place via the singlet excited state of the C(60) moiety in both polar and non-polar solvents. The charge-separated state, in which an electron is localized on the C(60) sphere and a hole is located on the whole donor moieties of ferrocene, pyrazole, and N,N-dimethylaniline groups, has been confirmed by nanosecond transient spectra in the visible and near-IR spectral region. The lifetimes of the radical ion-pairs are as long as 30 - 50 ns in both polar and non-polar solvents.

Liquid-Crystalline [60]Fullerene-TTF Dyads

[structure: see text] [60]Fullerene was functionalized with a TTF derivative and a bis-mesogenic fragment. The synthetic methodology was based on the addition of a malonate derivative to C60 (Bingel-type reaction). Both the malonate and dyad showed smectic B and A phases. The supramolecular organization within the smectic layers was of the monolayer type for the malonate and of the bilayer type for the fullerene derivative. In the latter case, the supramolecular organization was governed by the C60 unit.

Ordering fullerene materials at nanometer dimensions

The combination of the hydrophobic fullerene core with hydrophilic functional groups of both ionic and nonionic nature produces organized structures with sizes that range from nanometer to micrometer length scales. The driving force toward this spontaneous organization is the amphiphilic character of the fullerene derivatives. To control both shape and size of the supramolecular assemblies and ultimately their function, important parameters that must be tuned are (i) the balance between the hydrophobic and the hydrophilic moieties, (ii) the effect of the environment, typically provided by simple solvents, (iii) the interface on which the aggregation occurs or, more precisely, surface templating effects, and (iv) the solvation process.