Ancillary ligand-regulated Ti(IV)-based metallocalixarene coordination cages for photocatalytic H 2 evolution.

High-valence Ti(IV)-based metallocalixarene coordination cages that are linked by oriented ancillary ligands are unknown so far. Herein, the first family of tunable calixarene-based coordination cages of Ti(IV) with a framework formula [Ti 12 (O i Pr) 12 (TBC[4]) 6 L 6 ] have been assembled from six {Ti 2 (O i Pr) 2 (TBC[4])} 2+ nodes and six pyridinedicarboxylic ligands. Furthermore, the {Ti12L6} cage showed strong photocatalytic H 2 evolution activity, and DFT studies were performed to explore its electronic structure.