Département de chimie moléculaire

A series of redox-responsive architectures featuring two bipyridinium units introduced onto the lower rim of a calixarene skeleton has been synthesized. The redox-triggered intramol. dimerization of the reduced bipyridiniums has been investigated by electrochem., spectroelectrochem. and by theor. chem. The spectroscopic signature of the intramol. dimers was found to evolve significantly with the size of the alkyl linker introduced between the calixarene skeleton and the bipyridinium units. On account of exptl. data supported by theor. calcns., these differences have been attributed to the extent of the orbital overlap in the $π$-dimerized species, involving either four or only two of the pyridine rings of the bipyridinium radical cations stacked in eclipsed or staggered conformations, resp. [on SciFinder(R)]