Bottom up synthesis of novel 4-connected Boron Imidazolate Frameworks

Papathanasiou Konstantinos.

Abstract: Introduction

In recent years functional porous materials have attracted a tremendous interest based on both their properties and promising applications in gas storage, separation, catalysis, and energy storage and conversion. To date, Metal Organic Frameworks (MOFs) and zeolites consist the most famous families of porous materials. Both categories can exhibit advantages such as the porosity and/or functionality but they suffer drawbacks (e.g. sensitivity to aqueous environments) too. Last decades Zeolitic Imidazolate Frameworks (ZIFs) arose as a special class of porous materials, which have not only the four connected topologies of zeolites, but also the high surface areas of MOFs. More specifically, a novel sub-family of ZIFs based on Boron imidazolates (BIFs) has been developed through the crosslinking of boron imidazolate ligands with tetrahedral cations (Li+ and Cu+). One fundamental feature of BIFs is that both three-connected tripodal ligands and four-connected tetrahedral ligands can be readily synthesized prior to solvothermal synthesis. In these recently reported BIFs with 4-connected zeotype topologies, the coordination mode of each metal center is always tetrahedral. Furthermore, for the synthetic design of neutral zeolitic BIFs, the selection of tetrahedral metal centers is currently still limited to Li+ and Cu+ ions. It is highly desirable to go beyond Li+ and Cu+ to include a much wider variety of metal ions, which might provide access to a broader range of zeolite topologies.

Results

In this presentation we discuss Boron Imidazolate Frameworks based on a battery of pre-synthesized 4-connected boron imidazolates with Cobalt(2+) cations. Using the unsubstituted imidazole as a reference, we explore the relationship between BIFs’ structures and potential properties in the field of catalysis. A systematic substitution (-methyl, -ethyl, -phenyl) of used imidazoles leads us to functionalize the synthesis as well as the properties of final porous products.

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