Self-assembly of conformation-adaptive dihydrophenazine-based coordination cages

In this study, we designed and synthesized three conformation-adaptive Pd 2 L 4 - and Pd 3 L 6 -type coordination cages based on three dihydrophenazine-based ligands with different lengths. Interestingly, the shorter ligands L1 and L2 self-assembled into Pd 2 L 4 -type coordination cages while the longer ligand L3 formed Pd 3 L 6 -type one, mainly driven by the anion template effect. All coordination cages were confirmed through single-crystal X-ray diffraction, and their structural conformations underwent great changes compared with those of their corresponding ligands. Moreover, the conformational changes also significantly affected their photophysical and electrochemical properties which were distinct from their parent ligands. This work investigates how dihydrophenazine ligands and their conformational changes affect the assembly of coordination cages. Self-assembly, in turn, can tune the conformation of dihydrophenazine units and their photophysical and redox properties.