Formation of a Polythreaded, Metal–Organic Framework Utilizing an Interlocked Hexadentate, Carboxylate Linker

Abstract

A unique hexacarboxylate linker was prepared on the basis of an interlocked [2]rotaxane motif. The linker contains four carboxylate groups attached to a rigid, H-shaped axle and two carboxylate units appended to a crown ether wheel. The resulting Zn II -based metal-organic framework material has a [a]

Influence of axle length on the rate and mechanism of shuttling in rigid H-shaped [2]rotaxanes

“…During our investigations on incorporating molecular shuttles into solid-state materials by using rotaxanes as linkers for metal–organic frameworks (MOFs), 9 we prepared a series of [2]rotaxane molecular shuttles with a rigid H-shaped axle. 10 We rationalised that it should also be possible to extend this motif by adding an increasing number of phenyl rings, or equally rigid groups, to prepare a series of molecular shuttles with a fairly wide variation in shuttling track length.…”

Mechanically interlocked molecules in metal–organic frameworks

“…First, an hexadentate ligand was synthesized containing four carboxylate groups at the H-shaped thread and two other carboxylate moieties to the crown ether. 65 The resulting MORF was obtained by reaction with zinc nitrate under solvothermal conditions. The network is characterized by three interpenetrated lattices each one built of alternating threads and macrocycles.…”

Integrating the Mechanical Bond into Metal-Organic Frameworks

“…43 Hexadentate linkers have also been prepared using an H-shaped axle and a crown ether wheel (Figure 4C) with four carboxylic acid groups on the axle and either two carboxylic acid or pyridine groups attached to the wheel. 44,45 Coordination to Zn(II) (Figure 4D) and Cu(II) produced MOFs with SBUs that combine coordinating groups from both the axle and wheel, and yield fascinating structures that contain identical but independent lattices woven together as a result of the mechanical bond rather than the more conventional catenation and interpenetration or threading of lattices (Figure 4E). As the binding of the macrocycle about the recognition site is now part of the interpenetration of the two lattices, if a molecular shuttle-based linker was utilized, the separation between the two interpenetrated lattices could vary in a precise and controllable manner.…”