A Forty Years' Stroll through the Realms of Organometallic Chemistry

Abstract

Karl Ziegler shares his experience of experimentation with organometallic chemistry over the time period of forty years. Karl shares his moment in one of the last days of November 1927, when Bahr and he observed that the deep red color of phenylisopropylpotassium in ether rapidly changed to a deep yellow on addition of stilbene. This represented the discovery of the first addition of an organo-metallic compound to a C=C double bond. By adding more and more butadiene to the deeply red-colored solution of phenylisopropylpotassium the color rapidly changes, with the first mole of butadiene, to a light orange, and with more butadiene passing over to paler and paler yellows. During his time in Heidelberg around 1936, he found in the course of experiments to distill butyllithium under high vacuum that the lithium alkyl smoothly decomposed into lithium hydride and 1-butene. The observation that organo-lithium compounds often function as “super Grignards,” their ability to metallate other compounds, the famous lithium–halogen exchange, the role organo-lithium compounds play in aryne chemistry, are among some of the most striking developments in this field.