Synthesis and material properties of supramolecules containing fluorinated organomercurials
MetadataShow full item record
This dissertation details the synthesis and analysis of novel supramolecular species that feature simple fluorinated organomercurials, such as trimeric perfluoroortho- phenylene mercury ([o-C6F4Hg]3). These organomercurials can complex a variety of unsaturated substrates including arenes and alkynes. The major emphasis was on developing molecular architectures that are held together in part by secondary Hg-Calkyne interactions. Diphenylpolyynes, hydrocarbons featuring extended regions of unsaturation, were found to complex with [o-C6F4Hg]3 in a series of adducts. While the internal structures of the hydrocarbons themselves were found to be basically unaltered, within the crystals the polyynes were physically separated from one another by intervening molecules of [o-C6F4Hg]3, preventing them from cross-linking. This leads to a substantial stabilizing effect, for example [o-C6F4Hg]3 and Ph(CC)4Ph form a 2:1 adduct that is stable at temperatures up to 120 ºC above the pure hydrocarbon. Adducts of [o-C6F4Hg]3 and molecules containing a 1,3,5-triethynyl benzene core display a variety of novel properties. 1,3,5-tris(trimethylsilylethynyl) benzene forms binary supramolecular stacks with [o-C6F4Hg]3. The structure also displays large cylindrical 1-dimensional cavities. These cavities are lined with non-polar groups, have an internal diameter of 6.2 Å, and remain stable in the absence of guests. The compound readily interacts with and reversibly adsorbs simple alkanes. 1,3,5-tris(phenylethynyl) benzene forms similar stacks with [o-C6F4Hg]3, albeit without the cavities. Upon irradiation with visible and ultraviolet light, this adduct emits a long-lived emission that was hitherto unreported. From computer calculations and lifetime measurements, it appears this radiation is the phosphorescence of the pure hydrocarbon. Intensive structural studies have also been performed on adducts containing polyaromatic compounds, including phenanthrene, and the organomercurials [o- C6F4Hg]3, pentafluorophenyl mercury chloride and bromide. These experiments were performed to determine if Lewis acid-p complexes could be made with monofunctional mercury compounds. Polyaromatic hydrocarbons, such as phenanthrene and diphenylacetylene, were used as the substrates for these investigations. While all the mercurials formed adducts with the substrates, the photophysical measurements were not uniform and indicate that [o-C6F4Hg]3 has a stronger heavy-atom effect because of the cooperativity of the three mercury atoms.
Taylor, Thomas Jackson (2007). Synthesis and material properties of supramolecules containing fluorinated organomercurials. Doctoral dissertation, Texas A&M University. Available electronically from