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Structure-Function Studies of Modular Aromatics That Form Molecular Organogels

Baddeley, Christopher Peter
http://rave.ohiolink.edu/etdc/view?acc_num=osu1243445872

Abstract Details

2009, Master of Science, Ohio State University, Chemistry.
Three urea-based aromatics 1-3, each with distinct steric and electronic characteristics, have been synthesized and their ability to undergo hierarchical assembly and gel organic solvents investigated. We have found that compound 1 promotes the sol-gel phase transition in primary alcohols (from CH3OH to C10H21OH; CGC < 15 mg/mL), while 2 and 3 do not. IR spectroscopy, X-ray powder diffraction (XRPD), and transmission electron microscopy (TEM) measurements show that 1 organizes into “cylinders” in primary alcohols, using three-centered hydrogen bonds and π-π aromatic interactions. The cylinders further organize into pairs through interdigitation of the methyl groups of the adjacent aromatic rings. Importantly, the lateral packing of the cylinders is enhanced as the bulk solvent polarity increases providing a mechanism for controlling the material’s morphology via the solvophobic effect. Molecular mechanics (Amber) and semiempirical (AM1) calculations suggested similar conformational behavior but distinct electronic properties of 1-3. Thus, π-deficient 2 without the methyl groups and π-rich 3 without aromatic nitrogen fail to promote the sol-gel phase transition in alcohols due to their inability to undergo effective hierarchical assembly, which is necessary for the formation of a 3D fibrillar network. In addition, we have found that the ultrasonication of a supersaturated solution of 1 is necessary for the gelation. Presumably, a fast exchange of the aggregates of 1 is assisted with sonic waves to allow for the effective and “error free” assembly wherein an entangled net of fibers capable of encapsulating solvent molecules is formed.
Jovica Badjic, PhD (Advisor)
Gideon Fraenkel, PhD (Committee Member)
87 p.
Chemistry
Gels; Gelation; Physical Organic; ChemistryGels; Gelation; Physical Organic; Chemistry

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Citations

  • Baddeley, C. P. (2009). Structure-Function Studies of Modular Aromatics That Form Molecular Organogels [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243445872

    APA Style (7th edition)

  • Baddeley, Christopher. Structure-Function Studies of Modular Aromatics That Form Molecular Organogels. 2009. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1243445872.

    MLA Style (8th edition)

  • Baddeley, Christopher. "Structure-Function Studies of Modular Aromatics That Form Molecular Organogels." Master's thesis, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1243445872

    Chicago Manual of Style (17th edition)

osu1243445872
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© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.