The Missing Link: A 2D Metal-Organic Rotaxane Framework (MORF) with One Rotaxane Linker and One Naked Linker

Abstract

The [2]pseudorotaxane formed between the dicationic axle 1,2-bis-(4,4′-bipyridinium-mono-N-oxide)ethane and dibenzo-24-crown-8 ether (DB24C8) can act as a bridging ligand between metal centers to form metal organic rotaxane frameworks (MORFs). When cadmium(II) is used as the metal center the resulting structure is a network in which two [2]pseudorotaxanes, two ‘naked’ axles and two triflate anions coordinate to the Cd(II) center in a trans,-trans,-trans-arrangement. The two different linking ligands form a 2D ‘square’ net with only one direction comprised of rotaxanes. These nets layer in an A–B–A–B fashion with the crown ether units of one layer blocking the openings of the next layer to eliminate the formation of channels.

Keywords:

• Nitrogen ligands
• Self-assembly
• Coordination polymer
• Metal organic framework
• Rotaxane

Acknowledgements

SJL thanks the Natural Sciences and Engineering Council of Canada for financial support for this research.