William L. Mock and Cucurbituril: The Resurrection of the Behrend Paper of 1905

In 1905, Robert Behrend reported the preparation of a substance that remained a dry powder despite absorbing water and that had the ability to absorb dyes from solution. Over seven decades later, William L. Mock repeated the Behrend synthesis and discovered cucurbituril, a remarkably symmetric molecule with a central cavity welcoming diverse guests. Mock et al. ploughed a lonely furrow in the 1980s, establishing the versatility of cucurbituril in the field of supramolecular chemistry, including a demonstration of the Huisgen click reaction in a molecular cavity.