Mechanically Interlocked Linkers inside Metal鈥揙rganic Frameworks: Effect of Ring Size on Rotational Dynamics

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• 作者：V. Nicholas Vukotic ; Christopher A. O鈥橩eefe ; Kelong Zhu ; Kristopher J. Harris ; Christine To ; Robert W. Schurko ; Stephen J. Loeb
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：August 5, 2015
• 年：2015
• 卷：137
• 期：30
• 页码：9643-9651
• 全文大小：723K
• ISSN：1520-5126

文摘

A series of metal鈥搊rganic 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 ²H 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.