Connecting two C_(60) stoppers to molecular wires:ultrafast intramolecular deactivation reactions

摘要

A new series of soluble dumbbell-type architectures constituted by pi-conjugated oligophenyleneethynylenes (OPEs) and two C_(60) stoppers have been prepared by using a convergent synthetic strategy.In particular,we base our approach on the systematic cross-coupling,palladium catalyzed Hagihara-Sonogashira reaction between aryl iodides and alkynyl derivatives.The cyclic voltammetry of the correspondingly synthesized system reveals amphoteric redox behavior and the lack of significant electronic communication between the oligo-arylalkynyl bridge and the two C_(60) moieties,which behave as two independent units.Excited state studies carried out by fluorescence and transition absorption spectroscopy show that,although a weak competitive electron transfer could operate in the deactivation process of the excited oligo-arylalkynyl bridges,their deactivation is mainly governed by energy transfer.