Alanes macrocyclic

Alan M. Sargeson is Professor Emeritus at the Research School of Chemistry, Canberra, Australia. His work has involved the synthesis, structure determination and characterization of metal-macrocycle complexes [29-31], Potential applications of his studies are in catalysis, organic synthesis and biology. 

Alan M. Sargeson Caged metal ions (macrocycles in three dimensions)... 

A careful look at the main "pigments of life" (as Professor Sir Alan Battersby from the University of Cambridge calls them), e.g. heme, chlorophyll, bacterio-chlorophyll, and vitamin Bi2, shows that they have several features in common. They all consist of four pyrrole-type rings, with a greater or lesser degree of unsaturation (depending on the macrocycle), and they have a rather unusual pattern of substituents on their peripheral p-carbons. 

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