Synthesis and material properties of supramolecules containing fluorinated organomercurials

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Title: Synthesis and material properties of supramolecules containing fluorinated organomercurials
Author: Taylor, Thomas Jackson
Abstract: 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 ?C 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 ? , 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 .
URI: http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1261
Date: 2009-05-15

Citation

Synthesis and material properties of supramolecules containing fluorinated organomercurials. Available electronically from http : / /hdl .handle .net /1969 .1 /ETD -TAMU -1261 .

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