A Binuclear CuII Metallacycle Capable of Discerning between Pyrazine and Its Different Methyl‐Substituted Derivatives Based on Reversible Intracage Metal–Ligand Binding

Abstract
Squashy cage: A flexible, spongelike, and reversible metal-binding Cu2L2 cage that can adjust its internal space in response to pyrazine and its derivatives based on a recognition sequence of pyrazine, 2,5-dimethylpyrazine, and 2-methylpyrazine (see figure) is described.