Metal–organic frameworks utilising an interlocked, hexadentate linker containing a tetra-carboxylate axle and a bis(pyridine) wheel

Abstract

A [2]rotaxane linker was synthesized which combines an H-shaped axle containing four 3-carboxyphenyl groups and a macrocyclic wheel with two 4-pyridyl groups. Metal-organic framework materials were prepared with Cu and Zn ions X-ray structures show that the materials contain unique frameworks that are threaded solely due to the interpenetrated nature of the linker.

Mechanically interlocked molecules in metal–organic frameworks

“…Alternatively, Cu(II) and Zn(II) MORFs were prepared from a tetracarboxylate H-shaped axle and a macrocycle bearing two 4-pyridyl groups. 66 2.1.5. [2]Pseudorotaxane linkers with a Texas-sized molecular box.…”

“…Alternatively, Cu( ii ) and Zn( ii ) MORFs were prepared from a tetracarboxylate H-shaped axle and a macrocycle bearing two 4-pyridyl groups. 66…”

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.…”

Template-Driven Assembly of Rare Hexameric Uranyl-Organic Rotaxane Networks Threaded on Dimeric Uranyl Chains

“…Similar to conventional methods to construct MOFs, multifarious MORFs structures can be successfully prepared by varying metal coordination environments or organic ligands. Up to now, a large amount of MORFs with one-dimensional (1D), two-dimensional (2D), or even three-dimensional (3D) structures have been synthesized through coordination assembly of various pseudorotaxane/rotaxane precursor compounds with different metal centers. − However, in comparison with traditional small-molecule linkers in MOFs, the inherent noncovalent feature of MIMs increases the difficulty to synthesize MORFs, especially those with sophisticated structures and potential applications as required …”