Self-Diffusion of Charged Polycyclic Systems and Their Parent Compounds: A PGSE NMR Study

摘要

Polycyclic anions with conjugated π electron systems have been investigated extensively in the last decades as test cases for Huckel theory. These systems have also been used to study ion-pairing phenomena. Although aggregation of organo-metallic compounds was predicted by theory and detected by experiment, polycyclic dianions with π-conjugation in which the charge is thought to be delocalized over a relatively large organic skeleton have been treated in most studies as isolated species. Streitwieser has shown that lithium salts of conjugated hydrocarbon dianions may exist as "ion triplets" in which the lithium cations are located on opposite faces of the dianion. It is therefore important to gain better insight into the actual species that prevail in the solution after metal reduction of polycyclic systems.