Synchronized “Click” and Templated Synthesis of a Fluorescent Pyrene Crown Ether

The reaction of methyl 6,8‐bisethynylpyrene‐2‐carboxylate with 1‐azido‐2‐{[2‐(2‐azidoethoxy)ethoxy]ethoxy}ethane using standard “click” chemistry produced a 1+1 crown ether (CPYR). The copper ions used both catalyse the reaction and provide a template for ensuring smooth cyclisation. The X‐ray crystal structure of the compound reveals the two triazole groups are non‐coplanar with the pyrene moiety. The triazole groups are more co‐planar with the pyrene subunit in the first‐excited singlet state as revealed by a density functional theory (DFT) calculated molecular structure (B3LYP, 6‐311G). Partially structured emission observed in acetonitrile is consistent with the calculation result. In acetonitrile solution the macrocycle CPYR interacts with a Na+ ion to form a complex in which the ion binds with the crown and the pyrene residue. A “click” crown ether macrocycle was prepared based around a fluorescent pyrene unit in reasonable yield. The macrocycle binds to a Na+ ion in MeCN, which interacts with oxygen atoms of the crown and the pyrene subunit.