Soluble porous salt frameworks

• Applicant: Professor Dr. Sebastian Henke
• Subject Area: Solid State and Surface Chemistry, Material Synthesis ; Inorganic Molecular Chemistry - Synthesis and Characterisation ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 415553115

The goal of this research project is to explore the design, synthesis, and characterisation of a novel family of soluble porous materials termed Porous Salt Frameworks (PSFs). These PSFs are composed of alkoxy-chain-functionalized organic building blocks combined with alkali metals (such as Na and Li) or alkaline earth metals (such as Ca). They exhibit a unique set of material properties, including the ability to be processed from aqueous or ethanolic solutions (not suspensions) and the capacity to rapidly crystallise from these solutions into permanently porous framework structures with advantageous gas sorption selectivities. Remarkably, these materials can be cyclically crystallised and dissolved while maintaining their microporous framework structure in the solid state. In the first phase of the project, we successfully developed Na-PSFs and Li-PSFs based on aromatic organic dicarboxylate building blocks. The second phase aims to expand the PSF family by incorporating organic building units with diverse geometries, leading to new PSFs with significantly enhanced porosity and improved chemical and mechanical stability. Additionally, we will systematically investigate the physicochemical parameters governing the PSF solution-processability (such as specific solubilities in different solvents, cyclic assembly and disassembly from solution, and pH-dependent assembly) as well as their functional porosity properties (including pore volume, pore size, and sorption selectivity for technologically relevant hydrocarbons). A key focus of this project is to unravel the assembly mechanism of the organic building blocks with the metal ions from concentrated solutions using advanced X-ray scattering techniques. Through these studies, we aim to establish critical composition-structure-property relationships that will deepen our understanding of this new class of porous materials. Ultimately, this research will pave the way for the practical application of PSFs in molecular separation, catalysis, and other important technological fields.

• DFG Programme: Research Grants