Self-Assembly of a Pd2L4 Hydrazone Molecular Cage Through Multiple Reaction Pathways

Molecular cages are preorganized molecules with a central cavity, typically formed through the self-assembly of their building blocks. This requires in most cases forming and breaking reversible bonds during the self-assembly reaction pathway for error correction to drive the reaction to the cage product. In this work, we focus on both Pd–ligand and hydrazone bonds implemented in the structure of a Pd2L4 hydrazone molecular cage. As the cage contains two different types of reversible bonds, we envisaged a cage formation comparative study by performing the self-assembly of the cage through 3 different reaction pathways involving the formation of Pd–ligand bonds, hydrazone bonds, or a combination of both. The 3 reaction pathways produce the self-assembly of the cage with yields ranging from 73% to 79%. Despite the complexity of the reaction the cage is formed in a very high yield, even for the reaction pathway that involves the formation of 16 bonds. This research paves the way for more sophisticated cage self-assembly designs.