Synthesis of Axially Chiral 4,4′-Bipyridines and Their Remarkably Selective Self-Assembly into Chiral Metallo-Supramolecular Squares

A preferred choice: Prochiral 3,3′,5,5′‐tetramethyl‐4,4′‐bipyridine can be converted into two types of axially chiral 4,4′‐bipyridine compounds, separable into enantiomers by chiral HPLC. The obtained enantiopure bipyridines were sufficiently stable in solution to be used in the self‐assembly of chiral metallo‐supramolecular squares, which reveal a remarkable preference for one of ten possible structures (shown here).