Impact of the Extended 1,1′-Bipyridinium Structure on the Electron Transfer and π-Dimer Formation. Spectroelectrochemical and Computational Study

Abstract

The electrochemical reduction of the extended 1,1′-bipyridinium dication was investigated in detail by means of semiquantitative in situ electron paramagnetic resonance (EPR), UV–vis–NIR spectroelectrochemistry, and density functional theory (DFT) calculations. It was found that in the extended 1,1′-bipyridinium cation radical the spin density is localized on one of the pyridinium centers, which is in contrast to charge delocalization within the 4,4′-bipyridinium radical cation reported in the literature. The charge and spin density separation in the extended 1,1′-bipyridinium cation radical leads to π-dimer formation in a triplet electronic configuration.

Recent advances in electrochemistry of pyridinium-based electrophores: A structronic approach

“…In this section, case studies of discrete pyridinium assemblies that are electronically loosely coupled such as dendrimeric electrophores, [32] electrophoric foldamers [33] and π-dimers based on oligoviologens [34,35] are not considered.…”