title: Mechanically Interlocked Linkers inside Metal-Organic Frameworks: Effect of Ring Size on Rotational Dynamics.
abstract: A series of metal-organic framework (MOF) materials has been prepared, each containing a mechanically interlocked molecule (MIM) as the linker and a copper(II) paddlewheel as the secondary building unit (SBU). The MIM linkers are [2]rotaxanes with varying sizes of crown ether macrocycles ([22]crown-6, 22C6; [24]crown-6, 24C6; [26]crown-6, 26C6; benzo[24]crown-6, B24C6) and an anilinium-based axle containing four carboxylate donor groups. Herein, the X-ray structures of MOFs UWCM-1 (no crown) and UWDM-1(22) are compared and demonstrate the effect of including a macrocycle around the axle of the linker. The rotaxane linkers are linear and result in nbo-type MOFs with void space that allows for motion of the interlocked macrocycle inside the MOF pores, while the macrocycle-free linker is bent and yields a MOF with a novel 12-connected bcc structure. Variable temperature (2)H solid-state nuclear magnetic resonance showed that the macrocycles in UWDM-1(22), UWDM-1(24), and UWDM-1(B24) undergo different degrees and rates of rotation depending on the size and shape of the macrocycle.
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: V Nicholas
authors.initials: VN
authors.lastname: Vukotic
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Christopher A
authors.initials: CA
authors.lastname: O'Keefe
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Kelong
authors.initials: K
authors.lastname: Zhu
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Kristopher J
authors.initials: KJ
authors.lastname: Harris
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Christine
authors.initials: C
authors.lastname: To
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Schurko
authors.affiliation: Department of Chemistry and Biochemistry, University of Windsor, Windsor, Ontario, Canada N9B 3P4.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Loeb