A Rotaxane Scaffold for the Construction of Multiporphyrinic Light-Harvesting Devices
Résumé
A sophisticated photoactive molecular device has
been prepared by combining recent concepts for the preparation
of multifunctional nanomolecules (click chemistry on
multifunctional scaffolds) with supramolecular chemistry
(self-assembly to prepare rotaxanes). Specifically, a clickable
[2]rotaxane scaffold incorporating a free-base porphyrin
stopper has been prepared and functionalized with ten peripheral
Zn(II)-porphyrin moieties. Electrochemical investigations
of the final compound revealed a peculiar behavior resulting
from the intramolecular coordination of the Zn(II)
porphyrin moieties to 1,2,3-triazole units. Finally, steady
state investigations of the compound combining Zn(II) and
free-base porphyrin moieties have shown that this compound
is a light-harvesting device capable of channeling the
light energy from the peripheral Zn(II)-porphyrin subunits to
the core by singlet–singlet energy transfer.