Post‐Assembly Modification of Homochiral Titanium–Organic Cages for Recognition and Separation of Molecular Isomers

Abstract

A chiral metal-organic cage (MOC) was extended and fixed into a porous framework using a post-assembly modification strategy, which made it easier to study the host-guest chemistry of the solidstate MOC using a single-crystal diffraction technique. Anionic Ti 4 L 6 (L = embonate) cage can be used as a 4connecting crystal engineering tecton, and its optical resolution was achieved, thus homochiral ΔΔΔΔ-and ΛΛΛΛ-[Ti 4 L 6 ] cages were obtained. Accordingly, a pair of homochiral cage-based microporous frameworks (PTC-236(Δ) and PTC-236(Λ)) were easily prepared by a post-assembly reaction. PTC-236 has rich recognition sites provided by the Ti 4 L 6 moieties, chiral channels and high framework stability, affording a single-crystal-tosingle-crystal transformation for guest structure analyses. Thus it was successfully utilized for the recognition and separation of isomeric molecules. This study provides a new approach for the orderly combination of well-defined MOCs into functional porous frameworks.

All-catecholate-stabilized black titanium-oxo clusters for efficient photothermal conversion

“…TOCs are oen grown as single crystals for precise structure determination, which is essential for establishing structure-property relationships at the molecular level. [16][17][18] While numerous TOCs with varying nuclearities and structures [19][20][21][22][23][24][25][26] have been discovered, including highnuclearity Ti 42 27 and Ti 52 , 28 many suffer from sensitivity to moisture due to the presence of alkoxy groups (-OR) derived from solvents or Ti(OR) 4 around their TiO cores. These alkoxy groups typically exhibit monodentate or bridging modes and offer insufficient protection.…”