Advisor

Sygula, Andrzej

Committee Member

Mead, Keith T.

Committee Member

Mlsna, Todd E.

Committee Member

Zhang, Dongmao

Committee Member

Foster, Stephen C.

Date of Degree

1-1-2015

Document Type

Dissertation - Open Access

Abstract

The discovery of the new allotropic forms of elemental carbon (e.g. fullerenes and carbon nanotubes) introduced a novel motif in supramolecular chemistry based on dispersion interactions of curved networks of sp2 hybridized carbon atoms. Buckybowls, the curve-shaped polycyclic aromatic hydrocarbons, appear to be ideal candidates for molecular receptors to recognize fullerenes. Corannulene, the smallest and the best studied buckybowl, has been recognized as one of the important pincers in developing molecular receptors for fullerenes. The main goal of our research is to synthesize corannulene-based molecular receptors for fullerenes with high binding affinities with the use of the pincers preorganized on tailor made tethers of proper topology. This dissertation describes the design, synthesis, and testing of two bis-corannulene receptors with Klärner’s tethers. First, molecular mechanics (MM) was employed for the assessment of the binding potential of the receptors with fullerenes. Next, the receptors were synthesized by Diels-Alder cycloaddition reactions with isocorannulenofuran and Klärner’s dienophiles followed by dehydration. Finally, 1H NMR titrations of both molecular tweezers with fullerenes C60 and C70 were performed. While the first receptor exhibits the affinity for fullerenes comparable to the previously reported corannulene based receptors, the other with longer, naphthalene based tether, exceeds the performance of the former systems by ca. two orders of magnitude and, in addition, shows an enhanced preference for C70 over C60. These results are in line with the predictions based on MM modeling. The x-ray crystal structure of the 1:1 complex of the larger receptor with C60 indicates that the tether not only preorganizes the pincers into a proper topology to accept the host, but also contributes to the dispersion based binding with the fullerene guests. Fullerenes and their derivatives are frequently used as electron acceptors in polymer based solar cells. By amalgamation of fullerenes with organic receptors, like the ones reported here, the novel surface bound structures can be constructed with potential applications in nanotechnology and material sciences.

URI

https://hdl.handle.net/11668/18636

Share

COinS