Diels-alder polymerization of a macrocyclic metal complex with p-benzoquinone

The (hemiporphyrazinato)nickel complexes 1, 2 exhibiting isobenzofuran moieties as diene functionalities are generated in the presence of p-benzoquinone. In case of an excess of p-benzoquinone, the occuiring DA reactions afford the model compounds 3, 4, while polymerization takes place if 1 is generated in the presence of an equimolar amount of p-benzoquinone. The introduction of the carbonyl groups between the two epoxy rings leads to structure fragments which undergo easy dehydration.