Controlling Geometrically Frustrated Assembly in Reticular Materials for Strain Induced Reactivity

• Applicant: Professor Dr. Frederik Haase
• Subject Area: Physical Chemistry of Solids and Surfaces, Material Characterisation ; Polymer Materials
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 550297945

The milestone advances in the field of reticular materials can be categorized as enhancements in structural control and enhancements in functionality. These achievements universally improve the appeal of reticular materials for research and applications. Advances have focused on structural control, while functionality is often delegated to predesigned functional groups on linkers and metal centers with little or no cooperativity, leading to material that behave like immobilized molecules. This has led to a situation, where reticular materials are astoundingly versatile scaffolds with little intrinsic functionality besides porosity. This is in stark contrast to typical solid-state chemistry, where almost all functionality is intrinsic. Thus, new approaches are needed that build on the available structural control to obtain intrinsically functional materials. In previous work, we used incompatibilities between linker and framework symmetry to generate frustration, which in turn led to rich and complex chemistry beyond the predesigned linkers, through size limited assembly into nanoscopic entities, sub-stoichiometry and dangling functional groups, and highly distorted metal nodes and organic linkers. These results demonstrated that frustration can be a powerful design principle to generate novel structures and functionalities in the backbone of reticular materials. The proposal aims to investigate the concept of geometric frustration in reticular materials to enhance their structural and functional diversity and generate strain induced reactivity. The research objectives are threefold: to understand the origins of frustration by analyzing linker design and stiffness-frustration relationships; to utilize frustration to introduce high-energy functional groups within reticular materials; to use frustration induced strain to activate functional groups within the material backbone. This involves selectively tuning distortions in metal-organic nodes and linkers and inducing periodic defects, particularly focusing on COFs for their potential for applications. Methodologically, the research entails systematic synthesis of MOFs and COFs, manipulating linker stiffness and introducing incompatible symmetries to induce controlled distortions and strain within the materials. The anticipated impact extends beyond the specific objectives and goals, potentially leading to the development of rationally designed quasicrystals, reticular materials with emergent optoelectronic properties, proton conductivity, and modulated catalytic and adsorption properties. Ultimately, the fine-tuning of properties within frustrated systems is expected to enable the controlled introduction of desired high-energy structural features, facilitating the rational design of reticular materials with tailored properties and emergent functionalities. Through harnessing frustration, this research aims to fundamentally expand the structural and functional possibilities of reticular materials.

• DFG Programme: Independent Junior Research Groups
• Major Instrumentation: Integrated solid and liquid handling robot
• Instrumentation Group: 1060 Dilutoren, Pipettiergeräte, Probennehmer