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((OPr)-Pr-i)(12)(TBC[4])(6)L-6] have been assembled from six {Ti-2((OPr)-Pr-i)(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.