Alan McLeod Sargeson FAA. 13 October 1930 — 29 December 2008

Alan Sargeson was an extraordinarily gifted inorganic chemist who consistently made important and lasting contributions to his discipline. His lifelong interests were in the area of coordination chemistry, especially in the stereochemistry and reactivity of complexes involving the transition element cobalt. Notable discoveries included the elucidation of the mechanisms of substitution reactions of cobalt complexes, the demonstration that amino acid amides and their esters and phosphate esters incorporated in properly designed metal complexes could achieve the high rates of hydrolysis displayed by enzyme reactions, and perhaps most notably the discovery of the ready formation of cage complexes in which the metal is fully encapsulated. His impact on his field was far reaching, his achievements were at the highest level and for more than 30 years he was among the few who dominated the field.