Docking in Metal-Organic Frameworks
Qiaowei Li,1,*
Wenyu Zhang,1,*
Ognjen 
. Miljani
,1
Chi-Hau Sue,2
Yan-Li Zhao,2
Lihua Liu,2
Carolyn B. Knobler,1
J. Fraser Stoddart,2
Omar M. Yaghi1
The use of metal-organic frameworks (MOFs) so far has largely
relied on nonspecific binding interactions to host small molecular
guests. We used long organic struts (~2 nanometers) incorporating
34- and 36-membered macrocyclic polyethers as recognition modules
in the construction of several crystalline primitive cubic frameworks
that engage in specific binding in a way not observed in passive,
open reticulated geometries. MOF-1001 is capable of docking
paraquat dication (PQT
2+) guests within the macrocycles in a
stereoelectronically controlled fashion. This act of specific
complexation yields quantitatively the corresponding MOF-1001
pseudorotaxanes, as confirmed by x-ray diffraction and by solid-
and solution-state nuclear magnetic resonance spectroscopic
studies performed on MOF-1001, its pseudorotaxanes, and their
molecular strut precursors. A control experiment involving the
attempted inclusion of PQT
2+ inside a framework (MOF-177) devoid
of polyether struts showed negligible uptake of PQT
2+, indicating
the importance of the macrocyclic polyether in PQT
2+ docking.
2 Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
* To whom correspondence should be addressed. E-mail: qwli{at}chem.ucla.edu (Q.L.); wyzhang{at}chem.ucla.edu (W.Z.)
