Significant advances within coordination chemistry have developed numerous metal-organic frameworks. Metal-organic frameworks consist of multiple transition metals bridged by organic ligands as building blocks for the generation of functional materials. Polyoxometalates (POMs) are anionic clusters of transition metal ions and oxygen atoms, and they represent a unique class of compounds suitable for use as building blocks. One POM of particular interest is hexavanadate ([V6O19]8-), which consists of vanadium ions in their most oxidized form; thus it is a strong oxidizing agent. Coordination of organic triols with hexavanadate yields stable POM-bridged materials. The triol ligand designed in this experiment has three elongated branches that would produce an optimally porous metal-organic framework. This material would allow substrates to interact with the hexavanadate components significantly, and therefore the polyoxometalate's oxidative properties will be maximally utilized. The synthesis of the ligand was achieved through a four-step scheme. First, trimethylsilylacetylene was reacted with 1,3,5-tribromobenzene according to the Sonogashira cross-coupling reaction, and the trimethylsilyl group was removed in the following deprotection step. The Sonogashira coupling with p-bromobenzoate extended the branches. Amidation of the ester with trishydroxymethylaminomethane (TRIS) yields the three-branched triol ligand. After each step flash chromatography and NMR spectroscopy were performed to purify and characterize the compounds. Current steps underway include coordinating the POM to the ligand.

Trisubstituted triol as an organic building block for the preparation of a polyoxometalate-based metal-organic framework

247th National Meeting (2014)

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