A dinuclear copper(II) macrocyclic pyrazole compound catalyses the oxidative polymerisation of 2,6-dimethylphenol

The single crystal X-ray structure of the compound [Cu2(EtPy24Pz)(NO3)2](NO3)2(H2O)7, with EtPy24Pz is 10,24-di(pyridin-2-ylethyl)-1,5,10,15,19,24,29,30,31,32-decaaza-6,14,20,28-tetramethyl)-pentacyclo-[24.2.1.15,8.112,15.119,22]dotriaconta-6,8(30),12(31),13,20,22(32),26(29),27-octaene, shows the copper(II) ions in a square pyramidal N4O environment, crystallographically related by a twofold axis, at a distance of 7.24 Å. EPR data provide evidence that the two copper (II) ions, enclosed in the macrocyclic ligand, can be brought closer together by bridging anions. A similar cooperation with the binding of dehydronated 2,6-dimethylphenol is considered to take place to incite the two-electron transfer which leads to the production of polyphenylene ether through the intermediate formation of a phenoxonium cation.