Photoinduced electron transfer processes of (E)-9-(4-nitrostyryl)anthracene in non-polar solvent medium: generation of long-lived charge-separated states $$^{\S }$$ §

Abstract

In the present study, photoinduced electron transfer (PET) dynamics between N,N-diethylaniline (DEA) and (E)-9-(4-nitrostyryl)anthracene ( $$\hbox {An-NO}_{2}$$ ) in a non-polar solvent medium {methylcyclohexane (MCH)}, has been investigated. The rate constant of back electron transfer ( $$\hbox {k}_{{\mathrm{BET}}}$$ ) for the $$\hbox {An-NO}_{2}$$ – DEA pair was $$\sim 3.8\times 10^{5}~\hbox {s}^{-1}$$ which is ca. 2 orders of magnitude less compared to the anthracene (An)-DEA (control) system. The results indicate that long-lived charge separated species can be generated using the design strategy used herein by achieving resonance stabilization of the excited state (acceptor) radical via conjugation. SYNOPSIS For N,N-diethylaniline/(E)-9-(4-nitrostyryl)anthracene donor-acceptor pair, the back electron transfer rate constant is $$\sim 2$$ orders of magnitude slower compared to N,N-diethylaniline/anthracene system. The results indicate that organic molecules with extended $$\uppi $$ -conjugation can be utilized for generating long-lived charge separated states via bimolecular PET, due to increased feasibility of charge delocalization.