Light-Driven Molecular Motors Embedded in Covalent Organic Frameworks

04 March 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


The incorporation of molecular machines into the backbone of porous framework structures will facilitate nano actuation, enhanced molecular transport, and other out-of-equilibrium host-guest phenomena in well-defined 3D solid materials. In this work, we detail the synthesis of a diamine-based light-driven molecular motor and its incorporation into a series of imine-based polymers and covalent organic frameworks (COF). We study structural and dynamic properties of the molecular building blocks and derived self-assembled solids with a series of spectroscopic, diffraction, and theoretical methods. Using an acid-catalyzed synthesis approach, we are able to obtain the first crystalline 2D COF with stacked hexagonal layers that contains 20 mol-% molecular motors. The COF features a specific pore volume and surface area of up to 0.45 cm3 g−1 and 604 m2 g−1, respectively. Given the molecular structure and bulkiness of the diamine motor, we study the supramolecular assembly of the COF layers and detail stacking disorders between adjacent layers. We finally probe the motor dynamics with in situ spectroscopic techniques revealing current limitations in the analysis of the these new materials and derive important analysis and design criteria as well as synthetic access to new generations of motorized porous framework materials.


Covalent Organic Frameworks
Molecular Machines
Light-Driven Molecular Motor
Responsive Materials
Porous materials
X-ray Scattering
Pair-Distribution Function

Supplementary materials

Supporting Information: Light-Driven Molecular Motors Embedded in Covalent Organic Frameworks
Synthesis, Materials, Methods, Characterization


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