[NaCu^II₄] Cluster from Alkali Template Assembly of Two Asymmetric End-On Azido-Bridged [Cu^II₂] Units

The cluster [NaCu₄L₂(N₃)₂](ClO₄) [1; H₃L is 2-(2‘-hydroxyphenyl)-1,3-bis[3‘-aza-4‘-(2‘ ‘-hydroxyphenyl)prop-4‘-en-1‘-yl]-1,3-imidazolidine] has been synthesized and structurally characterized. Complex 1 is formed by the template assembly of two [Cu₂L(N₃)] neutral fragments through their weak oxophilic interactions with a central Na⁺ cation as observed in metallacrowns. The cluster exhibits a combination of ferro- and antiferromagnetic interactions. End-on N₃^- bridging of copper ions within the [Cu^II₂] units facilitates stabilization of S = 1 magnetic subunits that mutually cancel via antiferromagnetic coupling as mediated by the O···Na⁺···O bridges.