  The synthesis, characterization and metal complexation of a new class of
perylene bisimides (PBIs) being an integral part of ethylenediaminetetraacetic
acid (EDTA) is reported. The simplest representative, namely derivative 1a, was
synthesized both by a convergent as well as a direct approach while the
elongated derivatives, 1b and 1c, were obtained only via a convergent synthetic
pathway. All these new prototypes of water-soluble perylenes are
bolaamphiphiles and were fully characterized by 1H- and 13C-NMR spectroscopy,
matrix assisted laser desorption ionization, time of flight (MALDI-TOF) mass
spectrometry and IR spectroscopy. In order to acquaint for the behaviour in
solution of our PBIs bearing dentritic wedges, the simplest derivative, 1a, was
chosen and tested by means of UV/Vis and fluorescence spectroscopy as well as
by zeta-potential measurements. A photoexcitation induced intramolecular
photo-electron transfer (PET) can be observed in these molecules. Therefore
potential applications as sensor can be imagined. Model compound 1a efficiently
coordinates trivalent metal cations both in water and in dimethyl sulfoxide
(DMSO). Significantly, the effects of the complexation strongly depend on the
aggregation state of the PBI molecules in solution. As a matter of fact, in
water, the presence of M3+ ions triggers the formation of light emitting
supramolecular aggregates (excimers). On the other hand, in DMSO-rich solutions
metal complexation leads to the suppression of the PET and leads to a strong
fluorescence enhancement.
