Dynamic network of intermolecular interactions in metal-organic frameworks functionalized by molecular machines

Abstract

Molecular machines enable external control of structural and dynamic phenomena at the atomic level. To efficiently transfer their tunable properties into designated functionalities, a detailed understanding of the impact of molecular embedding is needed. In particular, a comprehensive insight is fundamental to design hierarchical multifunctional systems that are inspired by biological cells. Here, we applied an on-the-fly trained force field to perform atomistic simulations of a systematically modified rotaxane functionalized metal-organic framework. Our atomistic studies reveal a symmetric and asymmetric interplay of the mechanically bonded rings (MBRs) within the framework depending on the local environment. As a result, their translational motion is modulated ranging from fast oscillatory behavior to cooperative and potentially directed shuttling. The derived picture of competitive interactions, which influence the operation mechanism of the MBRs embedded in these soft porous materials, promotes the development of responsive functional materials, which is a key step toward intelligent matter.

Substitution and Orientation Effects on the Crystallinity and PFAS Adsorption of Olefin-Linked 2D COFs

“…The existence of a sharp, intense diffraction peak at 5.1° indicated the high crystallinity of COF-I, which is representative of the (100) plane in this new hexagonal olefin-linked 2D COF. To deduce the structure and the configuration of the layers in COF-I, we performed atomistic simulations (Figure b). − Following the previously introduced parametrization approach and studies − and utilizing the Tinker code, we parametrized a force field using quantum-mechanical (QM) reference data (BLYP+D3/cc-pVDZ). − By using these interatomic potentials to optimize both the geometry of the COF and the cell parameters and systematically varying the interlayer arrangement, we could discriminate the three-dimensional structures energetically. These atomistic simulations revealed that, for the solvent-free structure, the energetically most preferred structure is a highly dense slipped layer stacking, which increases the interaction between the layers.…”

Theoretical trends in the dynamics simulations of molecular machines across multiple scales

“…While atomic simulations are indispensable for providing static information and translation rates within hierarchical multifunctional systems at the equilibrium stage, 75 they may fall short when addressing phase transitions in self-assembly that extend beyond equilibrium. In such cases, DPD simulations come to the fore.…”

Functional dynamics in framework materials

“…In contrast, Kolodzeiski et al. investigated cooperative shuttling in a rotaxane-based MOF and the collective behavior that can arise from such a complex system 75 . However, among the most intriguing and thought-after properties is directed activated diffusion (i.e., pumping) via the rotational motion of molecular motors in porous frameworks.…”