Metal complexes of bibracchial Schiff base macrocycles

This article discusses polynuclear metal complexes of Schiff base macrocycles and their potential application to the modelling of metallobiosites, in particular di- and tri-nuclear copper(II)-containing sites. A brief perspective of the area is presented and then the article addresses the development of pyridinyl-derived bibracchial (doubly pendant-armed) Schiff base macrocycles and their metal complexes. The cleft-like configurations of the complexes bear resemblance to the metal-containing pockets present in metalloproteins. A 'first generation' model for the trinuclear copper site in ascorbate oxidase, and a dinuclear manganese(II) complex bearing a single acetato-bridge, and which may have relevance to the modelling of dinuclear manganese biosites, are discussed. An extension of the work to thiophene-derived macrocycles and their dicopper(I) complexes is also presented.