Complexation studies of calixnaphthalenes and hexahomotrioxacalixnaphthalenes with [60] fullerene

Mizyed, Shehadeh A. (2001) Complexation studies of calixnaphthalenes and hexahomotrioxacalixnaphthalenes with [60] fullerene. Doctoral (PhD) thesis, Memorial University of Newfoundland.

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Abstract

Calixarenes 1-3 are cyclic oligomers of p -substituted phenols and formaldehyde which have been used as hosts in supramolecular chemistry. A related group of molecules are the naphthalene ring-based calixnaphthalenes e.g. (8 and 9 ) and hexahomotrioxacalix[3]arene e.g. 19 . This thesis describes the ability of calixnaphthalenes to form complexes with C60 in different solvents using different methods. It also describes the first synthesis of hexahomotrioxacalix[3]naphthalenes and their complexation properties.* Calix[4]naphthalenes 8 and 9 have deeper cavities than those of the analogous calix[4]arenes and our physiochemical data confirm they do form complexes with C60 . Results obtained for the complexation of C60 with the C4 -symmetrical endo -calix[4] naphthalene 8 and its tert -butyl-substituted derivative 9 using uv-vis spectrophotometry show that they form relatively stable supramolecular 1:1 complexes with C 60 in toluene, benzene and CS2 solution. Thermodynamic parameters have also been determined for the complexation of 8 and 9 with C60 and show that both a solvophobic effect and π-π interactions are major driving forces for the complexation process. The symmetrical hexahomotrioxacalix[3]naphthalene 26 and its tert -butyl-substituted derivative 26a were synthesized via either the cyclization of the linear precursors 48 or 48a respectively, or by the direct cyclization of the monomers 46 or 46a respectively. The unsymmetrical hexahomotrioxacalix[3]naphthalene 27 was also obtained from the cyclization of the linear precursor 48 . Complexation studies showed that the ability of 26 and 26a to bind alkali metal cations was not significant. However, as shown by 1 H NMR studies they do form stable 1:1 complexes with C60 in solution. A crystalline 2:1 complex of 26a with C60 was isolated and its X-ray structure was successfully determined. Using densitometry, partial molar volume changes were determined for the complexation of 8, 9, 26 , or 26a with C 60 in toluene, benzene or CS2 solution. The results are consistent with a solvophobic effect, and some other additional factors which are discussed. Ester derivatives of hexahomotrioxacalix[3]naphthalenes in both the "cone" 49 (or 50 ) and the "partial-cone" 49a (or 50a ) conformations were synthesized and the X-ray crystal structure of 49a was determined. The ability of these esters to bind with alkali metal cations using standard extraction experiments is described. *Please refer to dissertation for diagrams.

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