Configurational ligand isomerism in conjoined-cages.

Double-decker shaped conjoined-cages of Pd 3 L 4 formulation are prepared via self-assembly of Pd(II) with a set of three regioisomeric tridentate ligands. Alongside the targeted double-decker cage, unprecedented hour-glass shaped conjoined-cages of Pd 3 L 4 formulation are also formed in two cases. The double-decker cage prepared from one ligand system and the hour-glass from another (but with a regioisomeric ligand) are structurally well suited to exemplify configurational ligand isomerism.