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Thermally Driven Dynamics of a Rotaxane Wheel about an Imidazolium Axle inside a Metal–Organic Framework
Author(s) -
Farahani Nasim,
Zhu Kelong,
O'Keefe Christopher A.,
Schurko Robert W.,
Loeb Stephen J.
Publication year - 2016
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201600176
Subject(s) - rotaxane , sbus , molecular machine , metal organic framework , linker , isophthalic acid , materials science , metathesis , crystallography , crown ether , chemistry , ion , crystal structure , polymer , nanotechnology , organic chemistry , polyester , composite material , polymerization , operating system , supramolecular chemistry , adsorption , terephthalic acid , computer science
A new mechanically interlocked molecular linker was prepared by using ring‐closing metathesis (Grubbs I) to clip a [24]crown‐6 ether wheel around an axle containing both Y‐shaped diphenylimidazole and isophthalic acid groups. A metal–organic framework (MOF) material was prepared using this linker and Zn II ions. Single‐crystal X‐ray diffraction experiments showed that the MOF contains an imidazolium‐based rotaxane linked by dimeric [Zn 2 (NO 3 )(DEF)] secondary building units (SBUs). Variable‐temperature (VT), 2 H solid‐state NMR spectroscopy was used to characterize the motion of the “soft” wheel component around the rigid “hard” lattice of the framework. At higher temperatures (above 150 °C), it was demonstrated that the 24‐membered, macrocyclic ring of the MOF undergoes rapid, thermally driven rotation about the axle inside the voids of the lattice.