Substituent-Dependent Photoexcitation Processes of π-Stacked Ion Pairs

Chemistry. 2023 Mar 7;29(14):e202203957. doi: 10.1002/chem.202203957. Epub 2023 Feb 7.

Abstract

Porphyrin ion pairs, the charge of which is delocalized in core units, form tightly associated structures through i π-i π interactions. 5,10,15-Triphenyl-substituted porphyrin-AuIII complex, which is favorable for forming stacked structures in the form of a stable ion, has been synthesized. Ion-pair metathesis based on the hard and soft acids and bases theory enabled combination with porphyrin anions possessing electronic states controlled by electron-donating and electron-withdrawing groups. Transient absorption spectroscopy suggested that the lifetimes of the radical pairs generated by photoinduced electron transfer of the ion pairs could be controlled by a judicious combination of the anions and cations.

Keywords: charged π-electronic systems; electron transfer; ion pairs; porphyrins; radicals.