Fig. 6: Effect of excess Pd²⁺ on (poly)MOC assembly.

A Schematic of the MOC-ligand equilibrium in the presence of excess Pd²⁺. The addition of super-stoichiometric Pd²⁺ drives the equilibrium to the right, producing free ligands coordinated to Pd (L1-Pd). B ¹H NMR spectra of MOC-OTf assembled on stoichiometry (1 equiv Pd²⁺), and with super-stoichiometric Pd²⁺ (4 equiv) with and without added DAQ. C Schematic of network degradation in the presence of super-stoichiometric Pd²⁺ and subsequent gelation upon addition of DAQ. Super-stoichiometric Pd²⁺ drives MOC structures into L-Pd₂ structures, lowering cross-linking functionality and ultimately causing network disassembly. Addition of DAQ stabilizes MOC structures in the presence of super-stoichiometric Pd²⁺ and subsequently drives MOC formation and gelation. D Photographs of sol-gel transitions caused by sequential additions of Pd²⁺ and DAQ to poly(OTf⊂MOC). E Phase diagram for gelation with 1 equiv. of each guest and varying super-stoichiometric Pd²⁺. The amount of Pd²⁺ that can be tolerated before gel degradation is proportional to guest binding strength. Gelation was assessed by the vial inversion test.