Electron dopable molecular wires based on the extended viologens

Abstract

Facile electron transfer in molecules with one dimension greatly exceeding the other two is essential in the development of new molecular electronic devices as these molecules can serve as so-called molecular wires. In this communication the electrochemical behavior of a series of molecules with multiple extended viologen moieties has been studied. We show that the electron transfer in the shortest wire is due to reduction of two identical communicating pyridinium moieties leading to a full charge delocalization, whereas the electron transfer in molecules with n ≥ 2 is due to reduction of initially non-communicating centers. This was confirmed by digital simulation of cyclic voltammograms. All studied molecules accept reversibly at least four and up to ten electrons without any long-term chemical changes, which is a prerequisite for their future application. Chemical stability of these molecules after multiple electron transfer was confirmed by in situUV-Vis spectroelectrochemical detection.