Synthesis, Structure, and Complexation Properties of Amide‐Substituted Derivatives of Norbornadiene and Quadricyclane

A molecular grapple with four clamping arms constructed from the quadricyclane⇄norbornadiene system can be controlled with light of two different wavelengths (see picture). In the presence of Na+ the open structure (middle) drops all arms and forms a stable complex (right). All three states of the “molecular grapple” were confirmed by X-ray analysis.