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Part A. Functional modular phenylacetylene units: A 'molecular turnstile.' Part B. Progress towards an electrochemically active 9-phenylcarbazole hyperbranched polymer

Posted on:1998-03-13Degree:Ph.DType:Dissertation
University:University of Illinois at Urbana-ChampaignCandidate:Bedard, Thomas CraigFull Text:PDF
GTID:1461390014478739Subject:Chemistry
Abstract/Summary:
Part A. Macrobicycles 75-77 have been prepared by palladium-catalyzed double macrocyclization. The planar geometry of this system is such that the para axis of the inner ring exactly matches the inner diameter of the macrocycle. Molecular models suggest that the inner ring of 75 should be able to rotate freely about its long axis, acting like the spindle of a turnstile. For large spindle substituents, this rotation will become hindered while for intermediate sized substituents, a pair of energetically equivalent conformational states should rapidly interconvert on an experimentally observable time scale. Substituted derivatives 76 and 77 possess diasterotopic methylene protons which become operationally enantiotopic upon fast rotation. Based on variable temperature {dollar}sp1{dollar} H NMR and longitudinal T{dollar}sb1{dollar} relaxation experiments, examples of what are believed to be freely rotating (76) and conformationally locked (77) spindles are reported. These molecules represent the first iteration in the development of phenylacetylene macrocycles possessing conformational bistability that may eventually lead to new types of solids or liquid crystals which respond rapidly to external electric fields.; Part B. Progress towards a new family of hyperbranched polymers based on the condensation of an AB{dollar}sb2{dollar} 9-phenylcarbazole monomer 169 has been described. Initial condensation reactions have provided material of greater than 100,000 mw as determined by GPC. No estimate of the degree of branching has been made. Evidence for olefinic linkages between carbazole units is provided by an observed red shifting in the absorption spectrum and chemical derivatization with bromine in carbon tetrachloride. These initial observations suggest that an in depth characterization of hyperbranched products from this family of compounds is warranted.
Keywords/Search Tags:Part, Hyperbranched
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