Chemical Reduction of a Nanosized [6]Cyclo‐2,7‐naphthylene Macrocycle

Abstract

Chemical reduction of a naphthylene macrocycle, [6]cyclo‐2,7‐naphthylene ([6]CNAP, 1 ), with alkali metals, Li and K, revealed the accessibility of the doubly‐reduced state of 1 . The macrocyclic 1 2− anion was isolated in different coordination environments and crystallographically characterized. The single‐crystal X‐ray diffraction confirmed the formation of contact‐ion complexes with one Li + and two K + ions in THF, and a “naked” dianion in the solvent‐separated ion product with K + ions in the presence of 18‐crown‐6 ether. The detailed structural analysis of 1 2− showed that the π‐conjugation over the biaryl linkages between naphthylene panels were enhanced upon two‐fold reduction, which was rationally explained by theoretical calculations.