Rotational Dynamics of Linkers in Metal–Organic Frameworks

Abstract

Among the numerous fascinating properties of metal–organic frameworks (MOFs), their rotational dynamics is perhaps one of the most intriguing, with clear consequences for adsorption and separation of molecules, as well as for optical and mechanical properties. A closer look at the rotational mobility in MOF linkers reveals that it is not only a considerably widespread phenomenon, but also a fairly diverse one. Still, the impact of these dynamics is often understated. In this review, we address the various mechanisms of linker rotation reported in the growing collection of literature, followed by a highlight of the methods currently used in their study, and we conclude with the impacts that such dynamics have on existing and future applications.

Multiple rotational rates in a guest-loaded, amphidynamic zirconia metal–organic framework

“…The interplay between guest diffusion, linker dynamics and the overall framework exibility has been actively investigated in recent years. 7 Here, we prepared a water-stable MOF, PEPEP-PIZOF-2 ( Fig. 1a), strategically labelled with deuterium atoms to probe the multiple segmental motion in the pristine and guest-loaded materials.…”

The Role of Molecular Modeling & Simulation in the Discovery and Deployment of Metal-Organic Frameworks for Gas Storage and Separation

“…Often, treating the MOF as a rigid "host" is an adequate approximation. 250 Some MOFs however, are known to have flexible backbones 251 or constituents (e.g., rotating ligands 252,253 ) that adopt different ensembles of configurations depending on temperature, the amount of adsorbed gas, and the mechanical stress imposed on the framework; the flexible modes of a MOF can dramatically influence adsorption. 121,247 Even small pore size fluctuations can be important to account for when the (average) pore size is commensurate with the size of the adsorbate.…”

Dielectric Spectroscopy of Water Dynamics in Functionalized UiO-66 Metal-Organic Frameworks

“…Attachment of the functional groups is also expected to influences the linker dynamics in UiO MOFs. In addition to NMR spectroscopy [23,24] and quasi-elastic neutron scattering [25], a method of choice to study such dynamic effects of polar linkers and guest molecules is dielectric spectroscopy [26][27][28][29]. This technique was used to probe the linker dynamics of functionalized UiO-66 with polar −Br, −OH and −NH 2 groups [30].…”