[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 [CuII2] units facilitates stabilization of S = 1 magnetic subunits that mutually cancel via antiferromagnetic coupling as mediated by the O···Na+···O bridges.