Chemistry – A European Journal

Abstract

In this review, the difference between π-mers (pimers) and π-dimers (pi-dimers) will be discussed. Often interchanged or confused in the literature, these two radical interactions lead to different or even opposite physico-chemical behaviors. This review aims at clarifying the terms π-mers and π-dimers and at describing their main physico-chemical properties to address their differences. Finally, selected literature examples exhibiting the successive formation of π-mers and π-dimers within the same systems will be detailed to emphasize the physico-chemical changes occurring upon conversion.

Graphical Abstract

π-mers and π-dimers are two radical interactions being easily confused on account of their similarities. This tutorial review introduces i) a clear definition of each interaction, ii) their main physico-chemical differences observable by major analytical techniques (X-Ray, UV/Vis/NIR, EPR, NMR and electrochemistry), iii) some of their thermodynamic features, and iii) examples showing strategies to enhance their stability (using a covalent spacer, a confined environment and mechanical bonds).