Oxalate-templated synthesis of di-zinc macrocycles

Oxalate serves as a template in the formation of di-zinc Schiff-base macrocycles linked by p- or m-xylylenes. NMR spectroscopy and X-ray crystallography both demonstrate symmetric structures containing μ2-κ2,κ2 oxalate. Treatment of one of the compounds with CaBr2 transforms bridging oxalate into the asymmetric μ2-κ1,κ2 form. The use of HCl enables oxalate removal as observed by ESI-MS.75