[2,2]Paracyclophane Bridged, Thiophene Based Macrocycles: Synthesis and Electronic Properties in Different Redox States

Abstract

AbstractThe study of through‐space electronic coupling in π‐conjugated systems remains an underexplored area. In this work, we present the facile synthesis of two isomeric macrocycles (1 and 2) bridged by [2,2]paracyclophane (pCp) and based on thiophene. The structures of these macrocycles have been confirmed through X‐ray crystallographic analysis. Our investigation centers on their electronic properties across various redox states, with a specific focus on potential through‐space electronic coupling and global aromaticity. Experimental measurements, including UV‐vis‐NIR electronic absorption, NMR, ESR spectra, and X‐ray diffraction, combined with theoretical calculations, reveal that both the neutral compounds and their tetracations exhibit a closed‐shell ground state. However, their dications manifest as diradical dications with a subtle magnetic exchange interaction. Consequently, the through‐space electronic coupling facilitated by the pCp unit in their respective ground states appears to be weak.