Abstract
By tuning the steric environment and free porespace in metal−organic frameworks, a large variety of rotordynamics of the organic linkers can appear. NitrofunctionalizedMIL-53 is a terephthalate-linker-based MOF that shows coupledrotor dynamics between the neighboring linkers along the poredirection. Here, we use classical molecular dynamics up to 6 × 2 ×2 supercells to investigate the range of the correlated linkerdynamics. Interestingly, we observe an PNPNPNPN... conforma-tional arrangement (P = nearly planar and N = nonplanar) for theconformations of the linkers in a row along the pore direction inthe MOF. We identified correlated linker dynamics emergingamong the direct and next nearest neighboring linkers along thepore. Due to 180° rotational flips of the planar linkers along the pore, (1) a change in the width of librations in their direct neighbors(PN) is observed; (2) intriguingly, their next nearest planar neighbors (PP) rotate between 0° and ±180° to reattain aligned (0°, 0°)or (±180°, ±180°) conformations. The presence of correlated dynamics in such linkers over long-length scales occurring atnanoseconds time scales is desirable for applications like ferroelectric switching or diffusion control via geared linker rotation, andthis work provides insight into the design for such applications.
