Bacteriochlorophyll a: influence of axial co-ordination on reactivity and stability. Design of an improved extraction procedure

Abstract

It is shown that the dehydrogenation of bacteriochlorophyll a is dependent on the co-ordination state of the central Mg atom. It is proposed that this reaction goes via the radical cation which is reactive when five-co-ordinate but stable when six-co-ordinate. These observations help design an extraction procedure which gives reproducibly high yields of indefinitely stable microcrystalline bacteriochlorophyll.