Self-Healing Pd(II) Cage Metallogels for Iodine Capture in Water and Heterogeneous Photocatalysis.

Adaptive multifunctional systems that integrate responsiveness, environmental remediation, and catalysis within a single platform remain exceptionally rare. Herein, two carbazole-derived metal-organic cages (MOCs) were constructed through coordination-driven self-assembly and subsequently transformed into fibrous metallogels (MOC1G and MOC2G) in mixed DMSO/H2O media through cooperative π-π stacking and dynamic supramolecular interactions. The resulting metallogels display reversible gel-sol transitions, interconnected nanofibrous architectures, and pronounced viscoelastic behavior. Rheological analyses revealed dominant elastic characteristics with rapid recovery after large mechanical deformation. Remarkably, the metallogels exhibit autonomous self-healing without external stimuli, restoring their structural integrity within ∼18 min for MOC1G and ∼14 min for MOC2G after mechanical damage. Temperature-dependent DLS and DSC studies further confirmed reversible thermally driven assembly-disassembly processes. Beyond their adaptive soft-matter properties, the discrete MOCs demonstrated highly efficient capture of iodine species from aqueous media, achieving uptake capacities up to 3.01 g g‒1 together with excellent selectivity and fast adsorption kinetics under both static and continuous-flow conditions. In addition, the cages function as visible-light-responsive heterogeneous photocatalysts for aerobic sulfide oxidation, affording sulfoxides under mild conditions. This work establishes the first example of cage-based metallogels that exhibit adaptive and autonomous self-healing behavior while integrating environmental remediation and photocatalytic functionality within a single supramolecular platform.